/*#define CHASE_CHAIN*/ /* * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998 * The Regents of the University of California. All rights reserved. * * Some portions Copyright (C) 2014 Cisco and/or its affiliates. All rights reserved. * Some portions Copyright (C) 2010-2013 Sourcefire, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #ifndef lint static const char __attribute__ ((unused)) rcsid[] = "@(#) $Header: /usr/cvsroot/sfeng/ims/src/libraries/daq/daq/sfbpf/sf_gencode.c,v 1.6 2014/06/10 13:38:55 cwaxman Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #ifdef WIN32 #include "win32-stdinc.h" #else /* WIN32 */ #if HAVE_INTTYPES_H #include #elif HAVE_STDINT_H #include #endif #ifdef HAVE_SYS_BITYPES_H #include #endif #include #include #endif /* WIN32 */ /* * XXX - why was this included even on UNIX? */ #ifdef __MINGW32__ #include "IP6_misc.h" #endif #ifndef WIN32 #ifdef __NetBSD__ #include #endif #include #include #endif /* WIN32 */ #include #include #include #include #include #include #ifdef MSDOS #include "pcap-dos.h" #endif #include "sfbpf-int.h" #include "ethertype.h" #include "nlpid.h" #include "llc.h" #include "gencode.h" #include "ieee80211.h" #include "atmuni31.h" #include "sunatmpos.h" #include "ppp.h" #include "sll.h" #include "ipnet.h" #include "arcnet.h" #ifdef HAVE_NET_PFVAR_H #include #include #include #include #endif #ifndef offsetof #define offsetof(s, e) ((size_t)&((s *)0)->e) #endif #ifdef INET6 #ifndef WIN32 #include /* for "struct addrinfo" */ #endif /* WIN32 */ #endif /*INET6 */ #include "namedb.h" #define ETHERMTU 1500 #ifndef IPPROTO_SCTP #define IPPROTO_SCTP 132 #endif #define JMP(c) ((c)|BPF_JMP|BPF_K) #if defined(__GNUC__) #pragma GCC diagnostic ignored "-Wunused-value" #endif /* __GNUC__ */ /* Locals */ static __thread jmp_buf top_ctx; static __thread char bpf_error_filter[PCAP_ERRBUF_SIZE + 1]; /* Hack for updating VLAN, MPLS, and PPPoE offsets. */ #ifdef WIN32 static u_int orig_linktype = (u_int) - 1, orig_nl = (u_int) - 1, label_stack_depth = (u_int) - 1; #else static __thread u_int orig_linktype = -1U, orig_nl = -1U, label_stack_depth = -1U; #endif /* XXX */ #ifdef PCAP_FDDIPAD static int pcap_fddipad; #endif /* VARARGS */ void bpf_error(const char *fmt, ...) { va_list ap; va_start(ap, fmt); (void) vsnprintf(bpf_error_filter, PCAP_ERRBUF_SIZE, fmt, ap); va_end(ap); longjmp(top_ctx, 1); /* NOTREACHED */ } static void init_linktype(int); static void init_regs(void); static int alloc_reg(void); static void free_reg(int); static __thread struct block *root; /* * Value passed to gen_load_a() to indicate what the offset argument * is relative to. */ enum e_offrel { OR_PACKET, /* relative to the beginning of the packet */ OR_LINK, /* relative to the beginning of the link-layer header */ OR_MACPL, /* relative to the end of the MAC-layer header */ OR_NET, /* relative to the network-layer header */ OR_NET_NOSNAP, /* relative to the network-layer header, with no SNAP header at the link layer */ OR_TRAN_IPV4, /* relative to the transport-layer header, with IPv4 network layer */ OR_TRAN_IPV6 /* relative to the transport-layer header, with IPv6 network layer */ }; #ifdef INET6 /* * As errors are handled by a longjmp, anything allocated must be freed * in the longjmp handler, so it must be reachable from that handler. * One thing that's allocated is the result of pcap_nametoaddrinfo(); * it must be freed with freeaddrinfo(). This variable points to any * addrinfo structure that would need to be freed. */ static struct addrinfo *ai; #endif /* * We divy out chunks of memory rather than call malloc each time so * we don't have to worry about leaking memory. It's probably * not a big deal if all this memory was wasted but if this ever * goes into a library that would probably not be a good idea. * * XXX - this *is* in a library.... */ #define NCHUNKS 16 #define CHUNK0SIZE 1024 struct chunk { u_int n_left; void *m; }; static __thread struct chunk chunks[NCHUNKS]; static __thread int cur_chunk; static void *newchunk(u_int); static void freechunks(void); static inline struct block *new_block(int); static inline struct slist *new_stmt(int); static struct block *gen_retblk(int); static inline void syntax(void); static void backpatch(struct block *, struct block *); static void merge(struct block *, struct block *); static struct block *gen_cmp(enum e_offrel, u_int, u_int, bpf_int32); static struct block *gen_cmp_gt(enum e_offrel, u_int, u_int, bpf_int32); static struct block *gen_cmp_ge(enum e_offrel, u_int, u_int, bpf_int32); static struct block *gen_cmp_lt(enum e_offrel, u_int, u_int, bpf_int32); static struct block *gen_cmp_le(enum e_offrel, u_int, u_int, bpf_int32); static struct block *gen_mcmp(enum e_offrel, u_int, u_int, bpf_int32, bpf_u_int32); static struct block *gen_bcmp(enum e_offrel, u_int, u_int, const u_char *); static struct block *gen_ncmp(enum e_offrel, bpf_u_int32, bpf_u_int32, bpf_u_int32, bpf_u_int32, int, bpf_int32); static struct slist *gen_load_llrel(u_int, u_int); static struct slist *gen_load_macplrel(u_int, u_int); static struct slist *gen_load_a(enum e_offrel, u_int, u_int); static struct slist *gen_loadx_iphdrlen(void); static struct block *gen_uncond(int); static inline struct block *gen_true(void); static inline struct block *gen_false(void); static struct block *gen_ether_linktype(int); static struct block *gen_ipnet_linktype(int); static struct block *gen_linux_sll_linktype(int); static struct slist *gen_load_prism_llprefixlen(void); static struct slist *gen_load_avs_llprefixlen(void); static struct slist *gen_load_radiotap_llprefixlen(void); static struct slist *gen_load_ppi_llprefixlen(void); static void insert_compute_vloffsets(struct block *); static struct slist *gen_llprefixlen(void); static struct slist *gen_off_macpl(void); static int ethertype_to_ppptype(int); static struct block *gen_linktype(int); static struct block *gen_snap(bpf_u_int32, bpf_u_int32); static struct block *gen_llc_linktype(int); static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int); #ifdef INET6 static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int); #endif static struct block *gen_ahostop(const u_char *, int); static struct block *gen_ehostop(const u_char *, int); static struct block *gen_fhostop(const u_char *, int); static struct block *gen_thostop(const u_char *, int); static struct block *gen_wlanhostop(const u_char *, int); static struct block *gen_ipfchostop(const u_char *, int); static struct block *gen_dnhostop(bpf_u_int32, int); static struct block *gen_mpls_linktype(int); static struct block *gen_host(bpf_u_int32, bpf_u_int32, int, int, int); #ifdef INET6 static struct block *gen_host6(struct in6_addr *, struct in6_addr *, int, int, int); #endif #ifndef INET6 static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int); #endif static struct block *gen_ipfrag(void); static struct block *gen_portatom(int, bpf_int32); static struct block *gen_portrangeatom(int, bpf_int32, bpf_int32); #ifdef INET6 static struct block *gen_portatom6(int, bpf_int32); static struct block *gen_portrangeatom6(int, bpf_int32, bpf_int32); #endif struct block *gen_portop(int, int, int); static struct block *gen_port(int, int, int); struct block *gen_portrangeop(int, int, int, int); static struct block *gen_portrange(int, int, int, int); #ifdef INET6 struct block *gen_portop6(int, int, int); static struct block *gen_port6(int, int, int); struct block *gen_portrangeop6(int, int, int, int); static struct block *gen_portrange6(int, int, int, int); #endif static int lookup_proto(const char *, int); static struct block *gen_protochain(int, int, int); static struct block *gen_proto(int, int, int); static struct slist *xfer_to_x(struct arth *); static struct slist *xfer_to_a(struct arth *); static struct block *gen_mac_multicast(int); static struct block *gen_len(int, int); static struct block *gen_check_802_11_data_frame(void); static struct block *gen_ppi_dlt_check(void); static struct block *gen_msg_abbrev(int type); static void *newchunk(n) u_int n; { struct chunk *cp; int k; size_t size; #ifndef __NetBSD__ /* XXX Round up to nearest long. */ n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1); #else /* XXX Round up to structure boundary. */ n = ALIGN(n); #endif cp = &chunks[cur_chunk]; if (n > cp->n_left) { ++cp, k = ++cur_chunk; if (k >= NCHUNKS) bpf_error("out of memory"); size = CHUNK0SIZE << k; cp->m = (void *) malloc(size); if (cp->m == NULL) bpf_error("out of memory"); memset((char *) cp->m, 0, size); cp->n_left = size; if (n > size) bpf_error("out of memory"); } cp->n_left -= n; return (void *) ((char *) cp->m + cp->n_left); } static void freechunks() { int i; cur_chunk = 0; for (i = 0; i < NCHUNKS; ++i) if (chunks[i].m != NULL) { free(chunks[i].m); chunks[i].m = NULL; } } /* * A strdup whose allocations are freed after code generation is over. */ char *sdup(s) register const char *s; { int n = strlen(s) + 1; char *cp = newchunk(n); strlcpy(cp, s, n); return (cp); } static inline struct block *new_block(code) int code; { struct block *p; p = (struct block *) newchunk(sizeof(*p)); p->s.code = code; p->head = p; return p; } static inline struct slist *new_stmt(code) int code; { struct slist *p; p = (struct slist *) newchunk(sizeof(*p)); p->s.code = code; return p; } static struct block *gen_retblk(v) int v; { struct block *b = new_block(BPF_RET | BPF_K); b->s.k = v; return b; } static inline void syntax() { bpf_error("syntax error in filter expression"); } static __thread bpf_u_int32 netmask; static __thread int snaplen; __thread int no_optimize; DAQ_SO_PUBLIC int pcap_compile(int snaplen_arg, int linktype_arg, struct bpf_program *program, const char *buf, int optimize, bpf_u_int32 mask) { extern __thread int n_errors; const char *volatile xbuf = buf; int len; no_optimize = 0; n_errors = 0; root = NULL; init_regs(); if (setjmp(top_ctx)) { #ifdef INET6 if (ai != NULL) { freeaddrinfo(ai); ai = NULL; } #endif lex_cleanup(); freechunks(); return (-1); } netmask = mask; snaplen = snaplen_arg; if (snaplen == 0) { snprintf(bpf_error_filter, PCAP_ERRBUF_SIZE, "snaplen of 0 rejects all packets"); return -1; } lex_init(xbuf ? xbuf : ""); init_linktype(linktype_arg); (void) pcap_parse(); if (n_errors) syntax(); if (root == NULL) root = gen_retblk(snaplen); if (optimize && !no_optimize) { bpf_optimize(&root); if (root == NULL || (root->s.code == (BPF_RET | BPF_K) && root->s.k == 0)) bpf_error("expression rejects all packets"); } program->bf_insns = icode_to_fcode(root, &len); program->bf_len = len; lex_cleanup(); freechunks(); return (0); } /* * Clean up a "struct bpf_program" by freeing all the memory allocated * in it. */ DAQ_SO_PUBLIC void pcap_freecode(struct bpf_program *program) { program->bf_len = 0; if (program->bf_insns != NULL) { free((char *) program->bf_insns); program->bf_insns = NULL; } } /* * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates * which of the jt and jf fields has been resolved and which is a pointer * back to another unresolved block (or nil). At least one of the fields * in each block is already resolved. */ static void backpatch(list, target) struct block *list, *target; { struct block *next; while (list) { if (!list->sense) { next = JT(list); JT(list) = target; } else { next = JF(list); JF(list) = target; } list = next; } } /* * Merge the lists in b0 and b1, using the 'sense' field to indicate * which of jt and jf is the link. */ static void merge(b0, b1) struct block *b0, *b1; { register struct block **p = &b0; /* Find end of list. */ while (*p) p = !((*p)->sense) ? &JT(*p) : &JF(*p); /* Concatenate the lists. */ *p = b1; } void finish_parse(p) struct block *p; { struct block *ppi_dlt_check; /* * Insert before the statements of the first (root) block any * statements needed to load the lengths of any variable-length * headers into registers. * * XXX - a fancier strategy would be to insert those before the * statements of all blocks that use those lengths and that * have no predecessors that use them, so that we only compute * the lengths if we need them. There might be even better * approaches than that. * * However, those strategies would be more complicated, and * as we don't generate code to compute a length if the * program has no tests that use the length, and as most * tests will probably use those lengths, we would just * postpone computing the lengths so that it's not done * for tests that fail early, and it's not clear that's * worth the effort. */ insert_compute_vloffsets(p->head); /* * For DLT_PPI captures, generate a check of the per-packet * DLT value to make sure it's DLT_IEEE802_11. */ ppi_dlt_check = gen_ppi_dlt_check(); if (ppi_dlt_check != NULL) gen_and(ppi_dlt_check, p); backpatch(p, gen_retblk(snaplen)); p->sense = !p->sense; backpatch(p, gen_retblk(0)); root = p->head; } void gen_and(b0, b1) struct block *b0, *b1; { backpatch(b0, b1->head); b0->sense = !b0->sense; b1->sense = !b1->sense; merge(b1, b0); b1->sense = !b1->sense; b1->head = b0->head; } void gen_or(b0, b1) struct block *b0, *b1; { b0->sense = !b0->sense; backpatch(b0, b1->head); b0->sense = !b0->sense; merge(b1, b0); b1->head = b0->head; } void gen_not(b) struct block *b; { b->sense = !b->sense; } static struct block *gen_cmp(offrel, offset, size, v) enum e_offrel offrel; u_int offset, size; bpf_int32 v; { return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v); } static struct block *gen_cmp_gt(offrel, offset, size, v) enum e_offrel offrel; u_int offset, size; bpf_int32 v; { return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 0, v); } static struct block *gen_cmp_ge(offrel, offset, size, v) enum e_offrel offrel; u_int offset, size; bpf_int32 v; { return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 0, v); } static struct block *gen_cmp_lt(offrel, offset, size, v) enum e_offrel offrel; u_int offset, size; bpf_int32 v; { return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGE, 1, v); } static struct block *gen_cmp_le(offrel, offset, size, v) enum e_offrel offrel; u_int offset, size; bpf_int32 v; { return gen_ncmp(offrel, offset, size, 0xffffffff, BPF_JGT, 1, v); } static struct block *gen_mcmp(offrel, offset, size, v, mask) enum e_offrel offrel; u_int offset, size; bpf_int32 v; bpf_u_int32 mask; { return gen_ncmp(offrel, offset, size, mask, BPF_JEQ, 0, v); } static struct block *gen_bcmp(offrel, offset, size, v) enum e_offrel offrel; register u_int offset, size; register const u_char *v; { register struct block *b, *tmp; b = NULL; while (size >= 4) { register const u_char *p = &v[size - 4]; bpf_int32 w = ((bpf_int32) p[0] << 24) | ((bpf_int32) p[1] << 16) | ((bpf_int32) p[2] << 8) | p[3]; tmp = gen_cmp(offrel, offset + size - 4, BPF_W, w); if (b != NULL) gen_and(b, tmp); b = tmp; size -= 4; } while (size >= 2) { register const u_char *p = &v[size - 2]; bpf_int32 w = ((bpf_int32) p[0] << 8) | p[1]; tmp = gen_cmp(offrel, offset + size - 2, BPF_H, w); if (b != NULL) gen_and(b, tmp); b = tmp; size -= 2; } if (size > 0) { tmp = gen_cmp(offrel, offset, BPF_B, (bpf_int32) v[0]); if (b != NULL) gen_and(b, tmp); b = tmp; } return b; } /* * AND the field of size "size" at offset "offset" relative to the header * specified by "offrel" with "mask", and compare it with the value "v" * with the test specified by "jtype"; if "reverse" is true, the test * should test the opposite of "jtype". */ static struct block *gen_ncmp(offrel, offset, size, mask, jtype, reverse, v) enum e_offrel offrel; bpf_int32 v; bpf_u_int32 offset, size, mask, jtype; int reverse; { struct slist *s, *s2; struct block *b; s = gen_load_a(offrel, offset, size); if (mask != 0xffffffff) { s2 = new_stmt(BPF_ALU | BPF_AND | BPF_K); s2->s.k = mask; sappend(s, s2); } b = new_block(JMP(jtype)); b->stmts = s; b->s.k = v; if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE)) gen_not(b); return b; } /* * Various code constructs need to know the layout of the data link * layer. These variables give the necessary offsets from the beginning * of the packet data. */ /* * This is the offset of the beginning of the link-layer header from * the beginning of the raw packet data. * * It's usually 0, except for 802.11 with a fixed-length radio header. * (For 802.11 with a variable-length radio header, we have to generate * code to compute that offset; off_ll is 0 in that case.) */ static __thread u_int off_ll; /* * If there's a variable-length header preceding the link-layer header, * "reg_off_ll" is the register number for a register containing the * length of that header, and therefore the offset of the link-layer * header from the beginning of the raw packet data. Otherwise, * "reg_off_ll" is -1. */ static __thread int reg_off_ll; /* * This is the offset of the beginning of the MAC-layer header from * the beginning of the link-layer header. * It's usually 0, except for ATM LANE, where it's the offset, relative * to the beginning of the raw packet data, of the Ethernet header. */ static __thread u_int off_mac; /* * This is the offset of the beginning of the MAC-layer payload, * from the beginning of the raw packet data. * * I.e., it's the sum of the length of the link-layer header (without, * for example, any 802.2 LLC header, so it's the MAC-layer * portion of that header), plus any prefix preceding the * link-layer header. */ static __thread u_int off_macpl; /* * This is 1 if the offset of the beginning of the MAC-layer payload * from the beginning of the link-layer header is variable-length. */ static __thread int off_macpl_is_variable; /* * If the link layer has variable_length headers, "reg_off_macpl" * is the register number for a register containing the length of the * link-layer header plus the length of any variable-length header * preceding the link-layer header. Otherwise, "reg_off_macpl" * is -1. */ static __thread int reg_off_macpl; /* * "off_linktype" is the offset to information in the link-layer header * giving the packet type. This offset is relative to the beginning * of the link-layer header (i.e., it doesn't include off_ll). * * For Ethernet, it's the offset of the Ethernet type field. * * For link-layer types that always use 802.2 headers, it's the * offset of the LLC header. * * For PPP, it's the offset of the PPP type field. * * For Cisco HDLC, it's the offset of the CHDLC type field. * * For BSD loopback, it's the offset of the AF_ value. * * For Linux cooked sockets, it's the offset of the type field. * * It's set to -1 for no encapsulation, in which case, IP is assumed. */ static __thread u_int off_linktype; /* * TRUE if "pppoes" appeared in the filter; it causes link-layer type * checks to check the PPP header, assumed to follow a LAN-style link- * layer header and a PPPoE session header. */ static __thread int is_pppoes = 0; /* * TRUE if the link layer includes an ATM pseudo-header. */ static __thread int is_atm = 0; /* * TRUE if "lane" appeared in the filter; it causes us to generate * code that assumes LANE rather than LLC-encapsulated traffic in SunATM. */ static __thread int is_lane = 0; /* * These are offsets for the ATM pseudo-header. */ static __thread u_int off_vpi; static __thread u_int off_vci; static __thread u_int off_proto; /* * These are offsets for the MTP2 fields. */ static __thread u_int off_li; /* * These are offsets for the MTP3 fields. */ static __thread u_int off_sio; static __thread u_int off_opc; static __thread u_int off_dpc; static __thread u_int off_sls; /* * This is the offset of the first byte after the ATM pseudo_header, * or -1 if there is no ATM pseudo-header. */ static __thread u_int off_payload; /* * These are offsets to the beginning of the network-layer header. * They are relative to the beginning of the MAC-layer payload (i.e., * they don't include off_ll or off_macpl). * * If the link layer never uses 802.2 LLC: * * "off_nl" and "off_nl_nosnap" are the same. * * If the link layer always uses 802.2 LLC: * * "off_nl" is the offset if there's a SNAP header following * the 802.2 header; * * "off_nl_nosnap" is the offset if there's no SNAP header. * * If the link layer is Ethernet: * * "off_nl" is the offset if the packet is an Ethernet II packet * (we assume no 802.3+802.2+SNAP); * * "off_nl_nosnap" is the offset if the packet is an 802.3 packet * with an 802.2 header following it. */ static __thread u_int off_nl; static __thread u_int off_nl_nosnap; static __thread int linktype; static void init_linktype(type) int type; { linktype = type; #ifdef PCAP_FDDIPAD pcap_fddipad = p->fddipad; #endif /* * Assume it's not raw ATM with a pseudo-header, for now. */ off_mac = 0; is_atm = 0; is_lane = 0; off_vpi = -1; off_vci = -1; off_proto = -1; off_payload = -1; /* * And that we're not doing PPPoE. */ is_pppoes = 0; /* * And assume we're not doing SS7. */ off_li = -1; off_sio = -1; off_opc = -1; off_dpc = -1; off_sls = -1; /* * Also assume it's not 802.11. */ off_ll = 0; off_macpl = 0; off_macpl_is_variable = 0; orig_linktype = -1; orig_nl = -1; label_stack_depth = 0; reg_off_ll = -1; reg_off_macpl = -1; switch (linktype) { case DLT_ARCNET: off_linktype = 2; off_macpl = 6; off_nl = 0; /* XXX in reality, variable! */ off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_ARCNET_LINUX: off_linktype = 4; off_macpl = 8; off_nl = 0; /* XXX in reality, variable! */ off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_EN10MB: off_linktype = 12; off_macpl = 14; /* Ethernet header length */ off_nl = 0; /* Ethernet II */ off_nl_nosnap = 3; /* 802.3+802.2 */ return; case DLT_SLIP: /* * SLIP doesn't have a link level type. The 16 byte * header is hacked into our SLIP driver. */ off_linktype = -1; off_macpl = 16; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_SLIP_BSDOS: /* XXX this may be the same as the DLT_PPP_BSDOS case */ off_linktype = -1; /* XXX end */ off_macpl = 24; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_NULL: case DLT_LOOP: off_linktype = 0; off_macpl = 4; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_ENC: off_linktype = 0; off_macpl = 12; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_PPP: case DLT_PPP_PPPD: case DLT_C_HDLC: /* BSD/OS Cisco HDLC */ case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */ off_linktype = 2; off_macpl = 4; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_PPP_ETHER: /* * This does no include the Ethernet header, and * only covers session state. */ off_linktype = 6; off_macpl = 8; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_PPP_BSDOS: off_linktype = 5; off_macpl = 24; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_FDDI: /* * FDDI doesn't really have a link-level type field. * We set "off_linktype" to the offset of the LLC header. * * To check for Ethernet types, we assume that SSAP = SNAP * is being used and pick out the encapsulated Ethernet type. * XXX - should we generate code to check for SNAP? */ off_linktype = 13; #ifdef PCAP_FDDIPAD off_linktype += pcap_fddipad; #endif off_macpl = 13; /* FDDI MAC header length */ #ifdef PCAP_FDDIPAD off_macpl += pcap_fddipad; #endif off_nl = 8; /* 802.2+SNAP */ off_nl_nosnap = 3; /* 802.2 */ return; case DLT_IEEE802: /* * Token Ring doesn't really have a link-level type field. * We set "off_linktype" to the offset of the LLC header. * * To check for Ethernet types, we assume that SSAP = SNAP * is being used and pick out the encapsulated Ethernet type. * XXX - should we generate code to check for SNAP? * * XXX - the header is actually variable-length. * Some various Linux patched versions gave 38 * as "off_linktype" and 40 as "off_nl"; however, * if a token ring packet has *no* routing * information, i.e. is not source-routed, the correct * values are 20 and 22, as they are in the vanilla code. * * A packet is source-routed iff the uppermost bit * of the first byte of the source address, at an * offset of 8, has the uppermost bit set. If the * packet is source-routed, the total number of bytes * of routing information is 2 plus bits 0x1F00 of * the 16-bit value at an offset of 14 (shifted right * 8 - figure out which byte that is). */ off_linktype = 14; off_macpl = 14; /* Token Ring MAC header length */ off_nl = 8; /* 802.2+SNAP */ off_nl_nosnap = 3; /* 802.2 */ return; case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: /* * 802.11 doesn't really have a link-level type field. * We set "off_linktype" to the offset of the LLC header. * * To check for Ethernet types, we assume that SSAP = SNAP * is being used and pick out the encapsulated Ethernet type. * XXX - should we generate code to check for SNAP? * * We also handle variable-length radio headers here. * The Prism header is in theory variable-length, but in * practice it's always 144 bytes long. However, some * drivers on Linux use ARPHRD_IEEE80211_PRISM, but * sometimes or always supply an AVS header, so we * have to check whether the radio header is a Prism * header or an AVS header, so, in practice, it's * variable-length. */ off_linktype = 24; off_macpl = 0; /* link-layer header is variable-length */ off_macpl_is_variable = 1; off_nl = 8; /* 802.2+SNAP */ off_nl_nosnap = 3; /* 802.2 */ return; case DLT_PPI: /* * At the moment we treat PPI the same way that we treat * normal Radiotap encoded packets. The difference is in * the function that generates the code at the beginning * to compute the header length. Since this code generator * of PPI supports bare 802.11 encapsulation only (i.e. * the encapsulated DLT should be DLT_IEEE802_11) we * generate code to check for this too. */ off_linktype = 24; off_macpl = 0; /* link-layer header is variable-length */ off_macpl_is_variable = 1; off_nl = 8; /* 802.2+SNAP */ off_nl_nosnap = 3; /* 802.2 */ return; case DLT_ATM_RFC1483: case DLT_ATM_CLIP: /* Linux ATM defines this */ /* * assume routed, non-ISO PDUs * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00) * * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS, * or PPP with the PPP NLPID (e.g., PPPoA)? The * latter would presumably be treated the way PPPoE * should be, so you can do "pppoe and udp port 2049" * or "pppoa and tcp port 80" and have it check for * PPPo{A,E} and a PPP protocol of IP and.... */ off_linktype = 0; off_macpl = 0; /* packet begins with LLC header */ off_nl = 8; /* 802.2+SNAP */ off_nl_nosnap = 3; /* 802.2 */ return; case DLT_SUNATM: /* * Full Frontal ATM; you get AALn PDUs with an ATM * pseudo-header. */ is_atm = 1; off_vpi = SUNATM_VPI_POS; off_vci = SUNATM_VCI_POS; off_proto = PROTO_POS; off_mac = -1; /* assume LLC-encapsulated, so no MAC-layer header */ off_payload = SUNATM_PKT_BEGIN_POS; off_linktype = off_payload; off_macpl = off_payload; /* if LLC-encapsulated */ off_nl = 8; /* 802.2+SNAP */ off_nl_nosnap = 3; /* 802.2 */ return; case DLT_RAW: case DLT_IPV4: case DLT_IPV6: off_linktype = -1; off_macpl = 0; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_LINUX_SLL: /* fake header for Linux cooked socket */ off_linktype = 14; off_macpl = 16; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_LTALK: /* * LocalTalk does have a 1-byte type field in the LLAP header, * but really it just indicates whether there is a "short" or * "long" DDP packet following. */ off_linktype = -1; off_macpl = 0; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_IP_OVER_FC: /* * RFC 2625 IP-over-Fibre-Channel doesn't really have a * link-level type field. We set "off_linktype" to the * offset of the LLC header. * * To check for Ethernet types, we assume that SSAP = SNAP * is being used and pick out the encapsulated Ethernet type. * XXX - should we generate code to check for SNAP? RFC * 2625 says SNAP should be used. */ off_linktype = 16; off_macpl = 16; off_nl = 8; /* 802.2+SNAP */ off_nl_nosnap = 3; /* 802.2 */ return; case DLT_FRELAY: /* * XXX - we should set this to handle SNAP-encapsulated * frames (NLPID of 0x80). */ off_linktype = -1; off_macpl = 0; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; /* * the only BPF-interesting FRF.16 frames are non-control frames; * Frame Relay has a variable length link-layer * so lets start with offset 4 for now and increments later on (FIXME); */ case DLT_MFR: off_linktype = -1; off_macpl = 0; off_nl = 4; off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */ return; case DLT_APPLE_IP_OVER_IEEE1394: off_linktype = 16; off_macpl = 18; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; case DLT_LINUX_IRDA: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_DOCSIS: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_SYMANTEC_FIREWALL: off_linktype = 6; off_macpl = 44; off_nl = 0; /* Ethernet II */ off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */ return; #ifdef HAVE_NET_PFVAR_H case DLT_PFLOG: off_linktype = 0; off_macpl = PFLOG_HDRLEN; off_nl = 0; off_nl_nosnap = 0; /* no 802.2 LLC */ return; #endif case DLT_JUNIPER_MFR: case DLT_JUNIPER_MLFR: case DLT_JUNIPER_MLPPP: case DLT_JUNIPER_PPP: case DLT_JUNIPER_CHDLC: case DLT_JUNIPER_FRELAY: off_linktype = 4; off_macpl = 4; off_nl = 0; off_nl_nosnap = -1; /* no 802.2 LLC */ return; case DLT_JUNIPER_ATM1: off_linktype = 4; /* in reality variable between 4-8 */ off_macpl = 4; /* in reality variable between 4-8 */ off_nl = 0; off_nl_nosnap = 10; return; case DLT_JUNIPER_ATM2: off_linktype = 8; /* in reality variable between 8-12 */ off_macpl = 8; /* in reality variable between 8-12 */ off_nl = 0; off_nl_nosnap = 10; return; /* frames captured on a Juniper PPPoE service PIC * contain raw ethernet frames */ case DLT_JUNIPER_PPPOE: case DLT_JUNIPER_ETHER: off_macpl = 14; off_linktype = 16; off_nl = 18; /* Ethernet II */ off_nl_nosnap = 21; /* 802.3+802.2 */ return; case DLT_JUNIPER_PPPOE_ATM: off_linktype = 4; off_macpl = 6; off_nl = 0; off_nl_nosnap = -1; /* no 802.2 LLC */ return; case DLT_JUNIPER_GGSN: off_linktype = 6; off_macpl = 12; off_nl = 0; off_nl_nosnap = -1; /* no 802.2 LLC */ return; case DLT_JUNIPER_ES: off_linktype = 6; off_macpl = -1; /* not really a network layer but raw IP addresses */ off_nl = -1; /* not really a network layer but raw IP addresses */ off_nl_nosnap = -1; /* no 802.2 LLC */ return; case DLT_JUNIPER_MONITOR: off_linktype = 12; off_macpl = 12; off_nl = 0; /* raw IP/IP6 header */ off_nl_nosnap = -1; /* no 802.2 LLC */ return; case DLT_JUNIPER_SERVICES: off_linktype = 12; off_macpl = -1; /* L3 proto location dep. on cookie type */ off_nl = -1; /* L3 proto location dep. on cookie type */ off_nl_nosnap = -1; /* no 802.2 LLC */ return; case DLT_JUNIPER_VP: off_linktype = 18; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_JUNIPER_ST: off_linktype = 18; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_JUNIPER_ISM: off_linktype = 8; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_MTP2: off_li = 2; off_sio = 3; off_opc = 4; off_dpc = 4; off_sls = 7; off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_MTP2_WITH_PHDR: off_li = 6; off_sio = 7; off_opc = 8; off_dpc = 8; off_sls = 11; off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_ERF: off_li = 22; off_sio = 23; off_opc = 24; off_dpc = 24; off_sls = 27; off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; #ifdef DLT_PFSYNC case DLT_PFSYNC: off_linktype = -1; off_macpl = 4; off_nl = 0; off_nl_nosnap = 0; return; #endif case DLT_LINUX_LAPD: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_USB: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_BLUETOOTH_HCI_H4: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_USB_LINUX: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_CAN20B: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_IEEE802_15_4_LINUX: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_IEEE802_16_MAC_CPS_RADIO: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_IEEE802_15_4: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_SITA: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_RAIF1: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_IPMB: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_BLUETOOTH_HCI_H4_WITH_PHDR: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_AX25_KISS: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; /* variable, min 15, max 71 steps of 7 */ off_macpl = -1; off_nl = -1; /* variable, min 16, max 71 steps of 7 */ off_nl_nosnap = -1; /* no 802.2 LLC */ off_mac = 1; /* step over the kiss length byte */ return; case DLT_IEEE802_15_4_NONASK_PHY: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_MPLS: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_USB_LINUX_MMAPPED: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_CAN_SOCKETCAN: /* * Currently, only raw "link[N:M]" filtering is supported. */ off_linktype = -1; off_macpl = -1; off_nl = -1; off_nl_nosnap = -1; return; case DLT_IPNET: off_linktype = 1; off_macpl = 24; /* ipnet header length */ off_nl = 0; off_nl_nosnap = -1; return; } bpf_error("unknown data link type %d", linktype); /* NOTREACHED */ } /* * Load a value relative to the beginning of the link-layer header. * The link-layer header doesn't necessarily begin at the beginning * of the packet data; there might be a variable-length prefix containing * radio information. */ static struct slist *gen_load_llrel(offset, size) u_int offset, size; { struct slist *s, *s2; s = gen_llprefixlen(); /* * If "s" is non-null, it has code to arrange that the X register * contains the length of the prefix preceding the link-layer * header. * * Otherwise, the length of the prefix preceding the link-layer * header is "off_ll". */ if (s != NULL) { /* * There's a variable-length prefix preceding the * link-layer header. "s" points to a list of statements * that put the length of that prefix into the X register. * do an indirect load, to use the X register as an offset. */ s2 = new_stmt(BPF_LD | BPF_IND | size); s2->s.k = offset; sappend(s, s2); } else { /* * There is no variable-length header preceding the * link-layer header; add in off_ll, which, if there's * a fixed-length header preceding the link-layer header, * is the length of that header. */ s = new_stmt(BPF_LD | BPF_ABS | size); s->s.k = offset + off_ll; } return s; } /* * Load a value relative to the beginning of the MAC-layer payload. */ static struct slist *gen_load_macplrel(offset, size) u_int offset, size; { struct slist *s, *s2; s = gen_off_macpl(); /* * If s is non-null, the offset of the MAC-layer payload is * variable, and s points to a list of instructions that * arrange that the X register contains that offset. * * Otherwise, the offset of the MAC-layer payload is constant, * and is in off_macpl. */ if (s != NULL) { /* * The offset of the MAC-layer payload is in the X * register. Do an indirect load, to use the X register * as an offset. */ s2 = new_stmt(BPF_LD | BPF_IND | size); s2->s.k = offset; sappend(s, s2); } else { /* * The offset of the MAC-layer payload is constant, * and is in off_macpl; load the value at that offset * plus the specified offset. */ s = new_stmt(BPF_LD | BPF_ABS | size); s->s.k = off_macpl + offset; } return s; } /* * Load a value relative to the beginning of the specified header. */ static struct slist *gen_load_a(offrel, offset, size) enum e_offrel offrel; u_int offset, size; { struct slist *s, *s2; switch (offrel) { case OR_PACKET: s = new_stmt(BPF_LD | BPF_ABS | size); s->s.k = offset; break; case OR_LINK: s = gen_load_llrel(offset, size); break; case OR_MACPL: s = gen_load_macplrel(offset, size); break; case OR_NET: s = gen_load_macplrel(off_nl + offset, size); break; case OR_NET_NOSNAP: s = gen_load_macplrel(off_nl_nosnap + offset, size); break; case OR_TRAN_IPV4: /* * Load the X register with the length of the IPv4 header * (plus the offset of the link-layer header, if it's * preceded by a variable-length header such as a radio * header), in bytes. */ s = gen_loadx_iphdrlen(); /* * Load the item at {offset of the MAC-layer payload} + * {offset, relative to the start of the MAC-layer * paylod, of the IPv4 header} + {length of the IPv4 header} + * {specified offset}. * * (If the offset of the MAC-layer payload is variable, * it's included in the value in the X register, and * off_macpl is 0.) */ s2 = new_stmt(BPF_LD | BPF_IND | size); s2->s.k = off_macpl + off_nl + offset; sappend(s, s2); break; case OR_TRAN_IPV6: s = gen_load_macplrel(off_nl + 40 + offset, size); break; default: abort(); return NULL; } return s; } /* * Generate code to load into the X register the sum of the length of * the IPv4 header and any variable-length header preceding the link-layer * header. */ static struct slist *gen_loadx_iphdrlen() { struct slist *s, *s2; s = gen_off_macpl(); if (s != NULL) { /* * There's a variable-length prefix preceding the * link-layer header, or the link-layer header is itself * variable-length. "s" points to a list of statements * that put the offset of the MAC-layer payload into * the X register. * * The 4*([k]&0xf) addressing mode can't be used, as we * don't have a constant offset, so we have to load the * value in question into the A register and add to it * the value from the X register. */ s2 = new_stmt(BPF_LD | BPF_IND | BPF_B); s2->s.k = off_nl; sappend(s, s2); s2 = new_stmt(BPF_ALU | BPF_AND | BPF_K); s2->s.k = 0xf; sappend(s, s2); s2 = new_stmt(BPF_ALU | BPF_LSH | BPF_K); s2->s.k = 2; sappend(s, s2); /* * The A register now contains the length of the * IP header. We need to add to it the offset of * the MAC-layer payload, which is still in the X * register, and move the result into the X register. */ sappend(s, new_stmt(BPF_ALU | BPF_ADD | BPF_X)); sappend(s, new_stmt(BPF_MISC | BPF_TAX)); } else { /* * There is no variable-length header preceding the * link-layer header, and the link-layer header is * fixed-length; load the length of the IPv4 header, * which is at an offset of off_nl from the beginning * of the MAC-layer payload, and thus at an offset * of off_mac_pl + off_nl from the beginning of the * raw packet data. */ s = new_stmt(BPF_LDX | BPF_MSH | BPF_B); s->s.k = off_macpl + off_nl; } return s; } static struct block *gen_uncond(rsense) int rsense; { struct block *b; struct slist *s; s = new_stmt(BPF_LD | BPF_IMM); s->s.k = !rsense; b = new_block(JMP(BPF_JEQ)); b->stmts = s; return b; } static inline struct block *gen_true() { return gen_uncond(1); } static inline struct block *gen_false() { return gen_uncond(0); } /* * Byte-swap a 32-bit number. * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on * big-endian platforms.) */ #define SWAPLONG(y) \ ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) /* * Generate code to match a particular packet type. * * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP * value, if <= ETHERMTU. We use that to determine whether to * match the type/length field or to check the type/length field for * a value <= ETHERMTU to see whether it's a type field and then do * the appropriate test. */ static struct block *gen_ether_linktype(proto) register int proto; { struct block *b0, *b1; switch (proto) { case LLCSAP_ISONS: case LLCSAP_IP: case LLCSAP_NETBEUI: /* * OSI protocols and NetBEUI always use 802.2 encapsulation, * so we check the DSAP and SSAP. * * LLCSAP_IP checks for IP-over-802.2, rather * than IP-over-Ethernet or IP-over-SNAP. * * XXX - should we check both the DSAP and the * SSAP, like this, or should we check just the * DSAP, as we do for other types <= ETHERMTU * (i.e., other SAP values)? */ b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU); gen_not(b0); b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32) ((proto << 8) | proto)); gen_and(b0, b1); return b1; case LLCSAP_IPX: /* * Check for; * * Ethernet_II frames, which are Ethernet * frames with a frame type of ETHERTYPE_IPX; * * Ethernet_802.3 frames, which are 802.3 * frames (i.e., the type/length field is * a length field, <= ETHERMTU, rather than * a type field) with the first two bytes * after the Ethernet/802.3 header being * 0xFFFF; * * Ethernet_802.2 frames, which are 802.3 * frames with an 802.2 LLC header and * with the IPX LSAP as the DSAP in the LLC * header; * * Ethernet_SNAP frames, which are 802.3 * frames with an LLC header and a SNAP * header and with an OUI of 0x000000 * (encapsulated Ethernet) and a protocol * ID of ETHERTYPE_IPX in the SNAP header. * * XXX - should we generate the same code both * for tests for LLCSAP_IPX and for ETHERTYPE_IPX? */ /* * This generates code to check both for the * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3. */ b0 = gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32) LLCSAP_IPX); b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32) 0xFFFF); gen_or(b0, b1); /* * Now we add code to check for SNAP frames with * ETHERTYPE_IPX, i.e. Ethernet_SNAP. */ b0 = gen_snap(0x000000, ETHERTYPE_IPX); gen_or(b0, b1); /* * Now we generate code to check for 802.3 * frames in general. */ b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU); gen_not(b0); /* * Now add the check for 802.3 frames before the * check for Ethernet_802.2 and Ethernet_802.3, * as those checks should only be done on 802.3 * frames, not on Ethernet frames. */ gen_and(b0, b1); /* * Now add the check for Ethernet_II frames, and * do that before checking for the other frame * types. */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) ETHERTYPE_IPX); gen_or(b0, b1); return b1; case ETHERTYPE_ATALK: case ETHERTYPE_AARP: /* * EtherTalk (AppleTalk protocols on Ethernet link * layer) may use 802.2 encapsulation. */ /* * Check for 802.2 encapsulation (EtherTalk phase 2?); * we check for an Ethernet type field less than * 1500, which means it's an 802.3 length field. */ b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU); gen_not(b0); /* * 802.2-encapsulated ETHERTYPE_ATALK packets are * SNAP packets with an organization code of * 0x080007 (Apple, for Appletalk) and a protocol * type of ETHERTYPE_ATALK (Appletalk). * * 802.2-encapsulated ETHERTYPE_AARP packets are * SNAP packets with an organization code of * 0x000000 (encapsulated Ethernet) and a protocol * type of ETHERTYPE_AARP (Appletalk ARP). */ if (proto == ETHERTYPE_ATALK) b1 = gen_snap(0x080007, ETHERTYPE_ATALK); else /* proto == ETHERTYPE_AARP */ b1 = gen_snap(0x000000, ETHERTYPE_AARP); gen_and(b0, b1); /* * Check for Ethernet encapsulation (Ethertalk * phase 1?); we just check for the Ethernet * protocol type. */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) proto); gen_or(b0, b1); return b1; default: if (proto <= ETHERMTU) { /* * This is an LLC SAP value, so the frames * that match would be 802.2 frames. * Check that the frame is an 802.2 frame * (i.e., that the length/type field is * a length field, <= ETHERMTU) and * then check the DSAP. */ b0 = gen_cmp_gt(OR_LINK, off_linktype, BPF_H, ETHERMTU); gen_not(b0); b1 = gen_cmp(OR_LINK, off_linktype + 2, BPF_B, (bpf_int32) proto); gen_and(b0, b1); return b1; } else { /* * This is an Ethernet type, so compare * the length/type field with it (if * the frame is an 802.2 frame, the length * field will be <= ETHERMTU, and, as * "proto" is > ETHERMTU, this test * will fail and the frame won't match, * which is what we want). */ return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) proto); } } } /* * "proto" is an Ethernet type value and for IPNET, if it is not IPv4 * or IPv6 then we have an error. */ static struct block *gen_ipnet_linktype(proto) register int proto; { switch (proto) { case ETHERTYPE_IP: return gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) IPH_AF_INET); /* NOTREACHED */ case ETHERTYPE_IPV6: return gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) IPH_AF_INET6); /* NOTREACHED */ default: break; } return gen_false(); } /* * Generate code to match a particular packet type. * * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP * value, if <= ETHERMTU. We use that to determine whether to * match the type field or to check the type field for the special * LINUX_SLL_P_802_2 value and then do the appropriate test. */ static struct block *gen_linux_sll_linktype(proto) register int proto; { struct block *b0, *b1; switch (proto) { case LLCSAP_ISONS: case LLCSAP_IP: case LLCSAP_NETBEUI: /* * OSI protocols and NetBEUI always use 802.2 encapsulation, * so we check the DSAP and SSAP. * * LLCSAP_IP checks for IP-over-802.2, rather * than IP-over-Ethernet or IP-over-SNAP. * * XXX - should we check both the DSAP and the * SSAP, like this, or should we check just the * DSAP, as we do for other types <= ETHERMTU * (i.e., other SAP values)? */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2); b1 = gen_cmp(OR_MACPL, 0, BPF_H, (bpf_int32) ((proto << 8) | proto)); gen_and(b0, b1); return b1; case LLCSAP_IPX: /* * Ethernet_II frames, which are Ethernet * frames with a frame type of ETHERTYPE_IPX; * * Ethernet_802.3 frames, which have a frame * type of LINUX_SLL_P_802_3; * * Ethernet_802.2 frames, which are 802.3 * frames with an 802.2 LLC header (i.e, have * a frame type of LINUX_SLL_P_802_2) and * with the IPX LSAP as the DSAP in the LLC * header; * * Ethernet_SNAP frames, which are 802.3 * frames with an LLC header and a SNAP * header and with an OUI of 0x000000 * (encapsulated Ethernet) and a protocol * ID of ETHERTYPE_IPX in the SNAP header. * * First, do the checks on LINUX_SLL_P_802_2 * frames; generate the check for either * Ethernet_802.2 or Ethernet_SNAP frames, and * then put a check for LINUX_SLL_P_802_2 frames * before it. */ b0 = gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32) LLCSAP_IPX); b1 = gen_snap(0x000000, ETHERTYPE_IPX); gen_or(b0, b1); b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2); gen_and(b0, b1); /* * Now check for 802.3 frames and OR that with * the previous test. */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_3); gen_or(b0, b1); /* * Now add the check for Ethernet_II frames, and * do that before checking for the other frame * types. */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) ETHERTYPE_IPX); gen_or(b0, b1); return b1; case ETHERTYPE_ATALK: case ETHERTYPE_AARP: /* * EtherTalk (AppleTalk protocols on Ethernet link * layer) may use 802.2 encapsulation. */ /* * Check for 802.2 encapsulation (EtherTalk phase 2?); * we check for the 802.2 protocol type in the * "Ethernet type" field. */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2); /* * 802.2-encapsulated ETHERTYPE_ATALK packets are * SNAP packets with an organization code of * 0x080007 (Apple, for Appletalk) and a protocol * type of ETHERTYPE_ATALK (Appletalk). * * 802.2-encapsulated ETHERTYPE_AARP packets are * SNAP packets with an organization code of * 0x000000 (encapsulated Ethernet) and a protocol * type of ETHERTYPE_AARP (Appletalk ARP). */ if (proto == ETHERTYPE_ATALK) b1 = gen_snap(0x080007, ETHERTYPE_ATALK); else /* proto == ETHERTYPE_AARP */ b1 = gen_snap(0x000000, ETHERTYPE_AARP); gen_and(b0, b1); /* * Check for Ethernet encapsulation (Ethertalk * phase 1?); we just check for the Ethernet * protocol type. */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) proto); gen_or(b0, b1); return b1; default: if (proto <= ETHERMTU) { /* * This is an LLC SAP value, so the frames * that match would be 802.2 frames. * Check for the 802.2 protocol type * in the "Ethernet type" field, and * then check the DSAP. */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, LINUX_SLL_P_802_2); b1 = gen_cmp(OR_LINK, off_macpl, BPF_B, (bpf_int32) proto); gen_and(b0, b1); return b1; } else { /* * This is an Ethernet type, so compare * the length/type field with it (if * the frame is an 802.2 frame, the length * field will be <= ETHERMTU, and, as * "proto" is > ETHERMTU, this test * will fail and the frame won't match, * which is what we want). */ return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) proto); } } } static struct slist *gen_load_prism_llprefixlen() { struct slist *s1, *s2; struct slist *sjeq_avs_cookie; struct slist *sjcommon; /* * This code is not compatible with the optimizer, as * we are generating jmp instructions within a normal * slist of instructions */ no_optimize = 1; /* * Generate code to load the length of the radio header into * the register assigned to hold that length, if one has been * assigned. (If one hasn't been assigned, no code we've * generated uses that prefix, so we don't need to generate any * code to load it.) * * Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes * or always use the AVS header rather than the Prism header. * We load a 4-byte big-endian value at the beginning of the * raw packet data, and see whether, when masked with 0xFFFFF000, * it's equal to 0x80211000. If so, that indicates that it's * an AVS header (the masked-out bits are the version number). * Otherwise, it's a Prism header. * * XXX - the Prism header is also, in theory, variable-length, * but no known software generates headers that aren't 144 * bytes long. */ if (reg_off_ll != -1) { /* * Load the cookie. */ s1 = new_stmt(BPF_LD | BPF_W | BPF_ABS); s1->s.k = 0; /* * AND it with 0xFFFFF000. */ s2 = new_stmt(BPF_ALU | BPF_AND | BPF_K); s2->s.k = 0xFFFFF000; sappend(s1, s2); /* * Compare with 0x80211000. */ sjeq_avs_cookie = new_stmt(JMP(BPF_JEQ)); sjeq_avs_cookie->s.k = 0x80211000; sappend(s1, sjeq_avs_cookie); /* * If it's AVS: * * The 4 bytes at an offset of 4 from the beginning of * the AVS header are the length of the AVS header. * That field is big-endian. */ s2 = new_stmt(BPF_LD | BPF_W | BPF_ABS); s2->s.k = 4; sappend(s1, s2); sjeq_avs_cookie->s.jt = s2; /* * Now jump to the code to allocate a register * into which to save the header length and * store the length there. (The "jump always" * instruction needs to have the k field set; * it's added to the PC, so, as we're jumping * over a single instruction, it should be 1.) */ sjcommon = new_stmt(JMP(BPF_JA)); sjcommon->s.k = 1; sappend(s1, sjcommon); /* * Now for the code that handles the Prism header. * Just load the length of the Prism header (144) * into the A register. Have the test for an AVS * header branch here if we don't have an AVS header. */ s2 = new_stmt(BPF_LD | BPF_W | BPF_IMM); s2->s.k = 144; sappend(s1, s2); sjeq_avs_cookie->s.jf = s2; /* * Now allocate a register to hold that value and store * it. The code for the AVS header will jump here after * loading the length of the AVS header. */ s2 = new_stmt(BPF_ST); s2->s.k = reg_off_ll; sappend(s1, s2); sjcommon->s.jf = s2; /* * Now move it into the X register. */ s2 = new_stmt(BPF_MISC | BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } static struct slist *gen_load_avs_llprefixlen() { struct slist *s1, *s2; /* * Generate code to load the length of the AVS header into * the register assigned to hold that length, if one has been * assigned. (If one hasn't been assigned, no code we've * generated uses that prefix, so we don't need to generate any * code to load it.) */ if (reg_off_ll != -1) { /* * The 4 bytes at an offset of 4 from the beginning of * the AVS header are the length of the AVS header. * That field is big-endian. */ s1 = new_stmt(BPF_LD | BPF_W | BPF_ABS); s1->s.k = 4; /* * Now allocate a register to hold that value and store * it. */ s2 = new_stmt(BPF_ST); s2->s.k = reg_off_ll; sappend(s1, s2); /* * Now move it into the X register. */ s2 = new_stmt(BPF_MISC | BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } static struct slist *gen_load_radiotap_llprefixlen() { struct slist *s1, *s2; /* * Generate code to load the length of the radiotap header into * the register assigned to hold that length, if one has been * assigned. (If one hasn't been assigned, no code we've * generated uses that prefix, so we don't need to generate any * code to load it.) */ if (reg_off_ll != -1) { /* * The 2 bytes at offsets of 2 and 3 from the beginning * of the radiotap header are the length of the radiotap * header; unfortunately, it's little-endian, so we have * to load it a byte at a time and construct the value. */ /* * Load the high-order byte, at an offset of 3, shift it * left a byte, and put the result in the X register. */ s1 = new_stmt(BPF_LD | BPF_B | BPF_ABS); s1->s.k = 3; s2 = new_stmt(BPF_ALU | BPF_LSH | BPF_K); sappend(s1, s2); s2->s.k = 8; s2 = new_stmt(BPF_MISC | BPF_TAX); sappend(s1, s2); /* * Load the next byte, at an offset of 2, and OR the * value from the X register into it. */ s2 = new_stmt(BPF_LD | BPF_B | BPF_ABS); sappend(s1, s2); s2->s.k = 2; s2 = new_stmt(BPF_ALU | BPF_OR | BPF_X); sappend(s1, s2); /* * Now allocate a register to hold that value and store * it. */ s2 = new_stmt(BPF_ST); s2->s.k = reg_off_ll; sappend(s1, s2); /* * Now move it into the X register. */ s2 = new_stmt(BPF_MISC | BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } /* * At the moment we treat PPI as normal Radiotap encoded * packets. The difference is in the function that generates * the code at the beginning to compute the header length. * Since this code generator of PPI supports bare 802.11 * encapsulation only (i.e. the encapsulated DLT should be * DLT_IEEE802_11) we generate code to check for this too; * that's done in finish_parse(). */ static struct slist *gen_load_ppi_llprefixlen() { struct slist *s1, *s2; /* * Generate code to load the length of the radiotap header * into the register assigned to hold that length, if one has * been assigned. */ if (reg_off_ll != -1) { /* * The 2 bytes at offsets of 2 and 3 from the beginning * of the radiotap header are the length of the radiotap * header; unfortunately, it's little-endian, so we have * to load it a byte at a time and construct the value. */ /* * Load the high-order byte, at an offset of 3, shift it * left a byte, and put the result in the X register. */ s1 = new_stmt(BPF_LD | BPF_B | BPF_ABS); s1->s.k = 3; s2 = new_stmt(BPF_ALU | BPF_LSH | BPF_K); sappend(s1, s2); s2->s.k = 8; s2 = new_stmt(BPF_MISC | BPF_TAX); sappend(s1, s2); /* * Load the next byte, at an offset of 2, and OR the * value from the X register into it. */ s2 = new_stmt(BPF_LD | BPF_B | BPF_ABS); sappend(s1, s2); s2->s.k = 2; s2 = new_stmt(BPF_ALU | BPF_OR | BPF_X); sappend(s1, s2); /* * Now allocate a register to hold that value and store * it. */ s2 = new_stmt(BPF_ST); s2->s.k = reg_off_ll; sappend(s1, s2); /* * Now move it into the X register. */ s2 = new_stmt(BPF_MISC | BPF_TAX); sappend(s1, s2); return (s1); } else return (NULL); } /* * Load a value relative to the beginning of the link-layer header after the 802.11 * header, i.e. LLC_SNAP. * The link-layer header doesn't necessarily begin at the beginning * of the packet data; there might be a variable-length prefix containing * radio information. */ static struct slist *gen_load_802_11_header_len(struct slist *s, struct slist *snext) { struct slist *s2; struct slist *sjset_data_frame_1; struct slist *sjset_data_frame_2; struct slist *sjset_qos; struct slist *sjset_radiotap_flags; struct slist *sjset_radiotap_tsft; struct slist *sjset_tsft_datapad, *sjset_notsft_datapad; struct slist *s_roundup; if (reg_off_macpl == -1) { /* * No register has been assigned to the offset of * the MAC-layer payload, which means nobody needs * it; don't bother computing it - just return * what we already have. */ return (s); } /* * This code is not compatible with the optimizer, as * we are generating jmp instructions within a normal * slist of instructions */ no_optimize = 1; /* * If "s" is non-null, it has code to arrange that the X register * contains the length of the prefix preceding the link-layer * header. * * Otherwise, the length of the prefix preceding the link-layer * header is "off_ll". */ if (s == NULL) { /* * There is no variable-length header preceding the * link-layer header. * * Load the length of the fixed-length prefix preceding * the link-layer header (if any) into the X register, * and store it in the reg_off_macpl register. * That length is off_ll. */ s = new_stmt(BPF_LDX | BPF_IMM); s->s.k = off_ll; } /* * The X register contains the offset of the beginning of the * link-layer header; add 24, which is the minimum length * of the MAC header for a data frame, to that, and store it * in reg_off_macpl, and then load the Frame Control field, * which is at the offset in the X register, with an indexed load. */ s2 = new_stmt(BPF_MISC | BPF_TXA); sappend(s, s2); s2 = new_stmt(BPF_ALU | BPF_ADD | BPF_K); s2->s.k = 24; sappend(s, s2); s2 = new_stmt(BPF_ST); s2->s.k = reg_off_macpl; sappend(s, s2); s2 = new_stmt(BPF_LD | BPF_IND | BPF_B); s2->s.k = 0; sappend(s, s2); /* * Check the Frame Control field to see if this is a data frame; * a data frame has the 0x08 bit (b3) in that field set and the * 0x04 bit (b2) clear. */ sjset_data_frame_1 = new_stmt(JMP(BPF_JSET)); sjset_data_frame_1->s.k = 0x08; sappend(s, sjset_data_frame_1); /* * If b3 is set, test b2, otherwise go to the first statement of * the rest of the program. */ sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(JMP(BPF_JSET)); sjset_data_frame_2->s.k = 0x04; sappend(s, sjset_data_frame_2); sjset_data_frame_1->s.jf = snext; /* * If b2 is not set, this is a data frame; test the QoS bit. * Otherwise, go to the first statement of the rest of the * program. */ sjset_data_frame_2->s.jt = snext; sjset_data_frame_2->s.jf = sjset_qos = new_stmt(JMP(BPF_JSET)); sjset_qos->s.k = 0x80; /* QoS bit */ sappend(s, sjset_qos); /* * If it's set, add 2 to reg_off_macpl, to skip the QoS * field. * Otherwise, go to the first statement of the rest of the * program. */ sjset_qos->s.jt = s2 = new_stmt(BPF_LD | BPF_MEM); s2->s.k = reg_off_macpl; sappend(s, s2); s2 = new_stmt(BPF_ALU | BPF_ADD | BPF_IMM); s2->s.k = 2; sappend(s, s2); s2 = new_stmt(BPF_ST); s2->s.k = reg_off_macpl; sappend(s, s2); /* * If we have a radiotap header, look at it to see whether * there's Atheros padding between the MAC-layer header * and the payload. * * Note: all of the fields in the radiotap header are * little-endian, so we byte-swap all of the values * we test against, as they will be loaded as big-endian * values. */ if (linktype == DLT_IEEE802_11_RADIO) { /* * Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set * in the presence flag? */ sjset_qos->s.jf = s2 = new_stmt(BPF_LD | BPF_ABS | BPF_W); s2->s.k = 4; sappend(s, s2); sjset_radiotap_flags = new_stmt(JMP(BPF_JSET)); sjset_radiotap_flags->s.k = SWAPLONG(0x00000002); sappend(s, sjset_radiotap_flags); /* * If not, skip all of this. */ sjset_radiotap_flags->s.jf = snext; /* * Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set? */ sjset_radiotap_tsft = sjset_radiotap_flags->s.jt = new_stmt(JMP(BPF_JSET)); sjset_radiotap_tsft->s.k = SWAPLONG(0x00000001); sappend(s, sjset_radiotap_tsft); /* * If IEEE80211_RADIOTAP_TSFT is set, the flags field is * at an offset of 16 from the beginning of the raw packet * data (8 bytes for the radiotap header and 8 bytes for * the TSFT field). * * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20) * is set. */ sjset_radiotap_tsft->s.jt = s2 = new_stmt(BPF_LD | BPF_ABS | BPF_B); s2->s.k = 16; sappend(s, s2); sjset_tsft_datapad = new_stmt(JMP(BPF_JSET)); sjset_tsft_datapad->s.k = 0x20; sappend(s, sjset_tsft_datapad); /* * If IEEE80211_RADIOTAP_TSFT is not set, the flags field is * at an offset of 8 from the beginning of the raw packet * data (8 bytes for the radiotap header). * * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20) * is set. */ sjset_radiotap_tsft->s.jf = s2 = new_stmt(BPF_LD | BPF_ABS | BPF_B); s2->s.k = 8; sappend(s, s2); sjset_notsft_datapad = new_stmt(JMP(BPF_JSET)); sjset_notsft_datapad->s.k = 0x20; sappend(s, sjset_notsft_datapad); /* * In either case, if IEEE80211_RADIOTAP_F_DATAPAD is * set, round the length of the 802.11 header to * a multiple of 4. Do that by adding 3 and then * dividing by and multiplying by 4, which we do by * ANDing with ~3. */ s_roundup = new_stmt(BPF_LD | BPF_MEM); s_roundup->s.k = reg_off_macpl; sappend(s, s_roundup); s2 = new_stmt(BPF_ALU | BPF_ADD | BPF_IMM); s2->s.k = 3; sappend(s, s2); s2 = new_stmt(BPF_ALU | BPF_AND | BPF_IMM); s2->s.k = ~3; sappend(s, s2); s2 = new_stmt(BPF_ST); s2->s.k = reg_off_macpl; sappend(s, s2); sjset_tsft_datapad->s.jt = s_roundup; sjset_tsft_datapad->s.jf = snext; sjset_notsft_datapad->s.jt = s_roundup; sjset_notsft_datapad->s.jf = snext; } else sjset_qos->s.jf = snext; return s; } static void insert_compute_vloffsets(b) struct block *b; { struct slist *s; /* * For link-layer types that have a variable-length header * preceding the link-layer header, generate code to load * the offset of the link-layer header into the register * assigned to that offset, if any. */ switch (linktype) { case DLT_PRISM_HEADER: s = gen_load_prism_llprefixlen(); break; case DLT_IEEE802_11_RADIO_AVS: s = gen_load_avs_llprefixlen(); break; case DLT_IEEE802_11_RADIO: s = gen_load_radiotap_llprefixlen(); break; case DLT_PPI: s = gen_load_ppi_llprefixlen(); break; default: s = NULL; break; } /* * For link-layer types that have a variable-length link-layer * header, generate code to load the offset of the MAC-layer * payload into the register assigned to that offset, if any. */ switch (linktype) { case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: s = gen_load_802_11_header_len(s, b->stmts); break; } /* * If we have any offset-loading code, append all the * existing statements in the block to those statements, * and make the resulting list the list of statements * for the block. */ if (s != NULL) { sappend(s, b->stmts); b->stmts = s; } } static struct block *gen_ppi_dlt_check(void) { struct slist *s_load_dlt; struct block *b; if (linktype == DLT_PPI) { /* Create the statements that check for the DLT */ s_load_dlt = new_stmt(BPF_LD | BPF_W | BPF_ABS); s_load_dlt->s.k = 4; b = new_block(JMP(BPF_JEQ)); b->stmts = s_load_dlt; b->s.k = SWAPLONG(DLT_IEEE802_11); } else { b = NULL; } return b; } static struct slist *gen_prism_llprefixlen(void) { struct slist *s; if (reg_off_ll == -1) { /* * We haven't yet assigned a register for the length * of the radio header; allocate one. */ reg_off_ll = alloc_reg(); } /* * Load the register containing the radio length * into the X register. */ s = new_stmt(BPF_LDX | BPF_MEM); s->s.k = reg_off_ll; return s; } static struct slist *gen_avs_llprefixlen(void) { struct slist *s; if (reg_off_ll == -1) { /* * We haven't yet assigned a register for the length * of the AVS header; allocate one. */ reg_off_ll = alloc_reg(); } /* * Load the register containing the AVS length * into the X register. */ s = new_stmt(BPF_LDX | BPF_MEM); s->s.k = reg_off_ll; return s; } static struct slist *gen_radiotap_llprefixlen(void) { struct slist *s; if (reg_off_ll == -1) { /* * We haven't yet assigned a register for the length * of the radiotap header; allocate one. */ reg_off_ll = alloc_reg(); } /* * Load the register containing the radiotap length * into the X register. */ s = new_stmt(BPF_LDX | BPF_MEM); s->s.k = reg_off_ll; return s; } /* * At the moment we treat PPI as normal Radiotap encoded * packets. The difference is in the function that generates * the code at the beginning to compute the header length. * Since this code generator of PPI supports bare 802.11 * encapsulation only (i.e. the encapsulated DLT should be * DLT_IEEE802_11) we generate code to check for this too. */ static struct slist *gen_ppi_llprefixlen(void) { struct slist *s; if (reg_off_ll == -1) { /* * We haven't yet assigned a register for the length * of the radiotap header; allocate one. */ reg_off_ll = alloc_reg(); } /* * Load the register containing the PPI length * into the X register. */ s = new_stmt(BPF_LDX | BPF_MEM); s->s.k = reg_off_ll; return s; } /* * Generate code to compute the link-layer header length, if necessary, * putting it into the X register, and to return either a pointer to a * "struct slist" for the list of statements in that code, or NULL if * no code is necessary. */ static struct slist *gen_llprefixlen(void) { switch (linktype) { case DLT_PRISM_HEADER: return gen_prism_llprefixlen(); case DLT_IEEE802_11_RADIO_AVS: return gen_avs_llprefixlen(); case DLT_IEEE802_11_RADIO: return gen_radiotap_llprefixlen(); case DLT_PPI: return gen_ppi_llprefixlen(); default: return NULL; } } /* * Generate code to load the register containing the offset of the * MAC-layer payload into the X register; if no register for that offset * has been allocated, allocate it first. */ static struct slist *gen_off_macpl(void) { struct slist *s; if (off_macpl_is_variable) { if (reg_off_macpl == -1) { /* * We haven't yet assigned a register for the offset * of the MAC-layer payload; allocate one. */ reg_off_macpl = alloc_reg(); } /* * Load the register containing the offset of the MAC-layer * payload into the X register. */ s = new_stmt(BPF_LDX | BPF_MEM); s->s.k = reg_off_macpl; return s; } else { /* * That offset isn't variable, so we don't need to * generate any code. */ return NULL; } } /* * Map an Ethernet type to the equivalent PPP type. */ static int ethertype_to_ppptype(proto) int proto; { switch (proto) { case ETHERTYPE_IP: proto = PPP_IP; break; #ifdef INET6 case ETHERTYPE_IPV6: proto = PPP_IPV6; break; #endif case ETHERTYPE_DN: proto = PPP_DECNET; break; case ETHERTYPE_ATALK: proto = PPP_APPLE; break; case ETHERTYPE_NS: proto = PPP_NS; break; case LLCSAP_ISONS: proto = PPP_OSI; break; case LLCSAP_8021D: /* * I'm assuming the "Bridging PDU"s that go * over PPP are Spanning Tree Protocol * Bridging PDUs. */ proto = PPP_BRPDU; break; case LLCSAP_IPX: proto = PPP_IPX; break; } return (proto); } /* * Generate code to match a particular packet type by matching the * link-layer type field or fields in the 802.2 LLC header. * * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP * value, if <= ETHERMTU. */ static struct block *gen_linktype(proto) register int proto; { struct block *b0, *b1, *b2; /* are we checking MPLS-encapsulated packets? */ if (label_stack_depth > 0) { switch (proto) { case ETHERTYPE_IP: case PPP_IP: /* FIXME add other L3 proto IDs */ return gen_mpls_linktype(Q_IP); case ETHERTYPE_IPV6: case PPP_IPV6: /* FIXME add other L3 proto IDs */ return gen_mpls_linktype(Q_IPV6); default: bpf_error("unsupported protocol over mpls"); /* NOTREACHED */ } } /* * Are we testing PPPoE packets? */ if (is_pppoes) { /* * The PPPoE session header is part of the * MAC-layer payload, so all references * should be relative to the beginning of * that payload. */ /* * We use Ethernet protocol types inside libpcap; * map them to the corresponding PPP protocol types. */ proto = ethertype_to_ppptype(proto); return gen_cmp(OR_MACPL, off_linktype, BPF_H, (bpf_int32) proto); } switch (linktype) { case DLT_EN10MB: return gen_ether_linktype(proto); /*NOTREACHED*/ break; case DLT_C_HDLC: switch (proto) { case LLCSAP_ISONS: proto = (proto << 8 | LLCSAP_ISONS); /* fall through */ default: return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) proto); /*NOTREACHED*/ break; } break; case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: /* * Check that we have a data frame. */ b0 = gen_check_802_11_data_frame(); /* * Now check for the specified link-layer type. */ b1 = gen_llc_linktype(proto); gen_and(b0, b1); return b1; /*NOTREACHED*/ break; case DLT_FDDI: /* * XXX - check for asynchronous frames, as per RFC 1103. */ return gen_llc_linktype(proto); /*NOTREACHED*/ break; case DLT_IEEE802: /* * XXX - check for LLC PDUs, as per IEEE 802.5. */ return gen_llc_linktype(proto); /*NOTREACHED*/ break; case DLT_ATM_RFC1483: case DLT_ATM_CLIP: case DLT_IP_OVER_FC: return gen_llc_linktype(proto); /*NOTREACHED*/ break; case DLT_SUNATM: /* * If "is_lane" is set, check for a LANE-encapsulated * version of this protocol, otherwise check for an * LLC-encapsulated version of this protocol. * * We assume LANE means Ethernet, not Token Ring. */ if (is_lane) { /* * Check that the packet doesn't begin with an * LE Control marker. (We've already generated * a test for LANE.) */ b0 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00); gen_not(b0); /* * Now generate an Ethernet test. */ b1 = gen_ether_linktype(proto); gen_and(b0, b1); return b1; } else { /* * Check for LLC encapsulation and then check the * protocol. */ b0 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0); b1 = gen_llc_linktype(proto); gen_and(b0, b1); return b1; } /*NOTREACHED*/ break; case DLT_LINUX_SLL: return gen_linux_sll_linktype(proto); /*NOTREACHED*/ break; case DLT_SLIP: case DLT_SLIP_BSDOS: case DLT_RAW: /* * These types don't provide any type field; packets * are always IPv4 or IPv6. * * XXX - for IPv4, check for a version number of 4, and, * for IPv6, check for a version number of 6? */ switch (proto) { case ETHERTYPE_IP: /* Check for a version number of 4. */ return gen_mcmp(OR_LINK, 0, BPF_B, 0x40, 0xF0); #ifdef INET6 case ETHERTYPE_IPV6: /* Check for a version number of 6. */ return gen_mcmp(OR_LINK, 0, BPF_B, 0x60, 0xF0); #endif default: return gen_false(); /* always false */ } /*NOTREACHED*/ break; case DLT_IPV4: /* * Raw IPv4, so no type field. */ if (proto == ETHERTYPE_IP) return gen_true(); /* always true */ /* Checking for something other than IPv4; always false */ return gen_false(); /*NOTREACHED*/ break; case DLT_IPV6: /* * Raw IPv6, so no type field. */ #ifdef INET6 if (proto == ETHERTYPE_IPV6) return gen_true(); /* always true */ #endif /* Checking for something other than IPv6; always false */ return gen_false(); /*NOTREACHED*/ break; case DLT_PPP: case DLT_PPP_PPPD: case DLT_PPP_SERIAL: case DLT_PPP_ETHER: /* * We use Ethernet protocol types inside libpcap; * map them to the corresponding PPP protocol types. */ proto = ethertype_to_ppptype(proto); return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) proto); /*NOTREACHED*/ break; case DLT_PPP_BSDOS: /* * We use Ethernet protocol types inside libpcap; * map them to the corresponding PPP protocol types. */ switch (proto) { case ETHERTYPE_IP: /* * Also check for Van Jacobson-compressed IP. * XXX - do this for other forms of PPP? */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_IP); b1 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJC); gen_or(b0, b1); b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, PPP_VJNC); gen_or(b1, b0); return b0; default: proto = ethertype_to_ppptype(proto); return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) proto); } /*NOTREACHED*/ break; case DLT_NULL: case DLT_LOOP: case DLT_ENC: /* * For DLT_NULL, the link-layer header is a 32-bit * word containing an AF_ value in *host* byte order, * and for DLT_ENC, the link-layer header begins * with a 32-bit work containing an AF_ value in * host byte order. * * In addition, if we're reading a saved capture file, * the host byte order in the capture may not be the * same as the host byte order on this machine. * * For DLT_LOOP, the link-layer header is a 32-bit * word containing an AF_ value in *network* byte order. * * XXX - AF_ values may, unfortunately, be platform- * dependent; for example, FreeBSD's AF_INET6 is 24 * whilst NetBSD's and OpenBSD's is 26. * * This means that, when reading a capture file, just * checking for our AF_INET6 value won't work if the * capture file came from another OS. */ switch (proto) { case ETHERTYPE_IP: proto = AF_INET; break; #ifdef INET6 case ETHERTYPE_IPV6: proto = AF_INET6; break; #endif default: /* * Not a type on which we support filtering. * XXX - support those that have AF_ values * #defined on this platform, at least? */ return gen_false(); } if (linktype == DLT_NULL || linktype == DLT_ENC) { /* * The AF_ value is in host byte order, but * the BPF interpreter will convert it to * network byte order. * * If this is a save file, and it's from a * machine with the opposite byte order to * ours, we byte-swap the AF_ value. * * Then we run it through "htonl()", and * generate code to compare against the result. */ //if (bpf_pcap->sf.rfile != NULL && bpf_pcap->sf.swapped) // proto = SWAPLONG(proto); proto = htonl(proto); } return (gen_cmp(OR_LINK, 0, BPF_W, (bpf_int32) proto)); #ifdef HAVE_NET_PFVAR_H case DLT_PFLOG: /* * af field is host byte order in contrast to the rest of * the packet. */ if (proto == ETHERTYPE_IP) return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af), BPF_B, (bpf_int32) AF_INET)); #ifdef INET6 else if (proto == ETHERTYPE_IPV6) return (gen_cmp(OR_LINK, offsetof(struct pfloghdr, af), BPF_B, (bpf_int32) AF_INET6)); #endif /* INET6 */ else return gen_false(); /*NOTREACHED*/ break; #endif /* HAVE_NET_PFVAR_H */ case DLT_ARCNET: case DLT_ARCNET_LINUX: /* * XXX should we check for first fragment if the protocol * uses PHDS? */ switch (proto) { default: return gen_false(); #ifdef INET6 case ETHERTYPE_IPV6: return (gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) ARCTYPE_INET6)); #endif /* INET6 */ case ETHERTYPE_IP: b0 = gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) ARCTYPE_IP); b1 = gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) ARCTYPE_IP_OLD); gen_or(b0, b1); return (b1); case ETHERTYPE_ARP: b0 = gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) ARCTYPE_ARP); b1 = gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) ARCTYPE_ARP_OLD); gen_or(b0, b1); return (b1); case ETHERTYPE_REVARP: return (gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) ARCTYPE_REVARP)); case ETHERTYPE_ATALK: return (gen_cmp(OR_LINK, off_linktype, BPF_B, (bpf_int32) ARCTYPE_ATALK)); } /*NOTREACHED*/ break; case DLT_LTALK: switch (proto) { case ETHERTYPE_ATALK: return gen_true(); default: return gen_false(); } /*NOTREACHED*/ break; case DLT_FRELAY: /* * XXX - assumes a 2-byte Frame Relay header with * DLCI and flags. What if the address is longer? */ switch (proto) { case ETHERTYPE_IP: /* * Check for the special NLPID for IP. */ return gen_cmp(OR_LINK, 2, BPF_H, (0x03 << 8) | 0xcc); #ifdef INET6 case ETHERTYPE_IPV6: /* * Check for the special NLPID for IPv6. */ return gen_cmp(OR_LINK, 2, BPF_H, (0x03 << 8) | 0x8e); #endif case LLCSAP_ISONS: /* * Check for several OSI protocols. * * Frame Relay packets typically have an OSI * NLPID at the beginning; we check for each * of them. * * What we check for is the NLPID and a frame * control field of UI, i.e. 0x03 followed * by the NLPID. */ b0 = gen_cmp(OR_LINK, 2, BPF_H, (0x03 << 8) | ISO8473_CLNP); b1 = gen_cmp(OR_LINK, 2, BPF_H, (0x03 << 8) | ISO9542_ESIS); b2 = gen_cmp(OR_LINK, 2, BPF_H, (0x03 << 8) | ISO10589_ISIS); gen_or(b1, b2); gen_or(b0, b2); return b2; default: return gen_false(); } /*NOTREACHED*/ break; case DLT_MFR: bpf_error("Multi-link Frame Relay link-layer type filtering not implemented"); case DLT_JUNIPER_MFR: case DLT_JUNIPER_MLFR: case DLT_JUNIPER_MLPPP: case DLT_JUNIPER_ATM1: case DLT_JUNIPER_ATM2: case DLT_JUNIPER_PPPOE: case DLT_JUNIPER_PPPOE_ATM: case DLT_JUNIPER_GGSN: case DLT_JUNIPER_ES: case DLT_JUNIPER_MONITOR: case DLT_JUNIPER_SERVICES: case DLT_JUNIPER_ETHER: case DLT_JUNIPER_PPP: case DLT_JUNIPER_FRELAY: case DLT_JUNIPER_CHDLC: case DLT_JUNIPER_VP: case DLT_JUNIPER_ST: case DLT_JUNIPER_ISM: /* just lets verify the magic number for now - * on ATM we may have up to 6 different encapsulations on the wire * and need a lot of heuristics to figure out that the payload * might be; * * FIXME encapsulation specific BPF_ filters */ return gen_mcmp(OR_LINK, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */ case DLT_IPNET: return gen_ipnet_linktype(proto); case DLT_LINUX_IRDA: bpf_error("IrDA link-layer type filtering not implemented"); case DLT_DOCSIS: bpf_error("DOCSIS link-layer type filtering not implemented"); case DLT_MTP2: case DLT_MTP2_WITH_PHDR: bpf_error("MTP2 link-layer type filtering not implemented"); case DLT_ERF: bpf_error("ERF link-layer type filtering not implemented"); #ifdef DLT_PFSYNC case DLT_PFSYNC: bpf_error("PFSYNC link-layer type filtering not implemented"); #endif case DLT_LINUX_LAPD: bpf_error("LAPD link-layer type filtering not implemented"); case DLT_USB: case DLT_USB_LINUX: case DLT_USB_LINUX_MMAPPED: bpf_error("USB link-layer type filtering not implemented"); case DLT_BLUETOOTH_HCI_H4: case DLT_BLUETOOTH_HCI_H4_WITH_PHDR: bpf_error("Bluetooth link-layer type filtering not implemented"); case DLT_CAN20B: case DLT_CAN_SOCKETCAN: bpf_error("CAN link-layer type filtering not implemented"); case DLT_IEEE802_15_4: case DLT_IEEE802_15_4_LINUX: case DLT_IEEE802_15_4_NONASK_PHY: bpf_error("IEEE 802.15.4 link-layer type filtering not implemented"); case DLT_IEEE802_16_MAC_CPS_RADIO: bpf_error("IEEE 802.16 link-layer type filtering not implemented"); case DLT_SITA: bpf_error("SITA link-layer type filtering not implemented"); case DLT_RAIF1: bpf_error("RAIF1 link-layer type filtering not implemented"); case DLT_IPMB: bpf_error("IPMB link-layer type filtering not implemented"); case DLT_AX25_KISS: bpf_error("AX.25 link-layer type filtering not implemented"); } /* * All the types that have no encapsulation should either be * handled as DLT_SLIP, DLT_SLIP_BSDOS, and DLT_RAW are, if * all packets are IP packets, or should be handled in some * special case, if none of them are (if some are and some * aren't, the lack of encapsulation is a problem, as we'd * have to find some other way of determining the packet type). * * Therefore, if "off_linktype" is -1, there's an error. */ if (off_linktype == (u_int) - 1) abort(); /* * Any type not handled above should always have an Ethernet * type at an offset of "off_linktype". */ return gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) proto); } /* * Check for an LLC SNAP packet with a given organization code and * protocol type; we check the entire contents of the 802.2 LLC and * snap headers, checking for DSAP and SSAP of SNAP and a control * field of 0x03 in the LLC header, and for the specified organization * code and protocol type in the SNAP header. */ static struct block *gen_snap(orgcode, ptype) bpf_u_int32 orgcode; bpf_u_int32 ptype; { u_char snapblock[8]; snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */ snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */ snapblock[2] = 0x03; /* control = UI */ snapblock[3] = (orgcode >> 16); /* upper 8 bits of organization code */ snapblock[4] = (orgcode >> 8); /* middle 8 bits of organization code */ snapblock[5] = (orgcode >> 0); /* lower 8 bits of organization code */ snapblock[6] = (ptype >> 8); /* upper 8 bits of protocol type */ snapblock[7] = (ptype >> 0); /* lower 8 bits of protocol type */ return gen_bcmp(OR_MACPL, 0, 8, snapblock); } /* * Generate code to match a particular packet type, for link-layer types * using 802.2 LLC headers. * * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues. * * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP * value, if <= ETHERMTU. We use that to determine whether to * match the DSAP or both DSAP and LSAP or to check the OUI and * protocol ID in a SNAP header. */ static struct block *gen_llc_linktype(proto) int proto; { /* * XXX - handle token-ring variable-length header. */ switch (proto) { case LLCSAP_IP: case LLCSAP_ISONS: case LLCSAP_NETBEUI: /* * XXX - should we check both the DSAP and the * SSAP, like this, or should we check just the * DSAP, as we do for other types <= ETHERMTU * (i.e., other SAP values)? */ return gen_cmp(OR_MACPL, 0, BPF_H, (bpf_u_int32) ((proto << 8) | proto)); case LLCSAP_IPX: /* * XXX - are there ever SNAP frames for IPX on * non-Ethernet 802.x networks? */ return gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32) LLCSAP_IPX); case ETHERTYPE_ATALK: /* * 802.2-encapsulated ETHERTYPE_ATALK packets are * SNAP packets with an organization code of * 0x080007 (Apple, for Appletalk) and a protocol * type of ETHERTYPE_ATALK (Appletalk). * * XXX - check for an organization code of * encapsulated Ethernet as well? */ return gen_snap(0x080007, ETHERTYPE_ATALK); default: /* * XXX - we don't have to check for IPX 802.3 * here, but should we check for the IPX Ethertype? */ if (proto <= ETHERMTU) { /* * This is an LLC SAP value, so check * the DSAP. */ return gen_cmp(OR_MACPL, 0, BPF_B, (bpf_int32) proto); } else { /* * This is an Ethernet type; we assume that it's * unlikely that it'll appear in the right place * at random, and therefore check only the * location that would hold the Ethernet type * in a SNAP frame with an organization code of * 0x000000 (encapsulated Ethernet). * * XXX - if we were to check for the SNAP DSAP and * LSAP, as per XXX, and were also to check for an * organization code of 0x000000 (encapsulated * Ethernet), we'd do * * return gen_snap(0x000000, proto); * * here; for now, we don't, as per the above. * I don't know whether it's worth the extra CPU * time to do the right check or not. */ return gen_cmp(OR_MACPL, 6, BPF_H, (bpf_int32) proto); } } } static struct block *gen_hostop(addr, mask, dir, proto, src_off, dst_off) bpf_u_int32 addr; bpf_u_int32 mask; int dir, proto; u_int src_off, dst_off; { struct block *b0, *b1; u_int offset; switch (dir) { case Q_SRC: offset = src_off; break; case Q_DST: offset = dst_off; break; case Q_AND: b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off); b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off); gen_and(b0, b1); return b1; case Q_OR: case Q_DEFAULT: b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off); b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off); gen_or(b0, b1); return b1; default: abort(); } b0 = gen_linktype(proto); b1 = gen_mcmp(OR_NET, offset, BPF_W, (bpf_int32) addr, mask); gen_and(b0, b1); return b1; } #ifdef INET6 static struct block *gen_hostop6(addr, mask, dir, proto, src_off, dst_off) struct in6_addr *addr; struct in6_addr *mask; int dir, proto; u_int src_off, dst_off; { struct block *b0, *b1; u_int offset; u_int32_t *a, *m; switch (dir) { case Q_SRC: offset = src_off; break; case Q_DST: offset = dst_off; break; case Q_AND: b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off); b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off); gen_and(b0, b1); return b1; case Q_OR: case Q_DEFAULT: b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off); b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off); gen_or(b0, b1); return b1; default: abort(); } /* this order is important */ a = (u_int32_t *) addr; m = (u_int32_t *) mask; b1 = gen_mcmp(OR_NET, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3])); b0 = gen_mcmp(OR_NET, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2])); gen_and(b0, b1); b0 = gen_mcmp(OR_NET, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1])); gen_and(b0, b1); b0 = gen_mcmp(OR_NET, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0])); gen_and(b0, b1); b0 = gen_linktype(proto); gen_and(b0, b1); return b1; } #endif /*INET6 */ static struct block *gen_ehostop(eaddr, dir) register const u_char *eaddr; register int dir; { register struct block *b0, *b1; switch (dir) { case Q_SRC: return gen_bcmp(OR_LINK, off_mac + 6, 6, eaddr); case Q_DST: return gen_bcmp(OR_LINK, off_mac + 0, 6, eaddr); case Q_AND: b0 = gen_ehostop(eaddr, Q_SRC); b1 = gen_ehostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_ehostop(eaddr, Q_SRC); b1 = gen_ehostop(eaddr, Q_DST); gen_or(b0, b1); return b1; } abort(); /* NOTREACHED */ } /* * Like gen_ehostop, but for DLT_FDDI */ static struct block *gen_fhostop(eaddr, dir) register const u_char *eaddr; register int dir; { struct block *b0, *b1; switch (dir) { case Q_SRC: #ifdef PCAP_FDDIPAD return gen_bcmp(OR_LINK, 6 + 1 + pcap_fddipad, 6, eaddr); #else return gen_bcmp(OR_LINK, 6 + 1, 6, eaddr); #endif case Q_DST: #ifdef PCAP_FDDIPAD return gen_bcmp(OR_LINK, 0 + 1 + pcap_fddipad, 6, eaddr); #else return gen_bcmp(OR_LINK, 0 + 1, 6, eaddr); #endif case Q_AND: b0 = gen_fhostop(eaddr, Q_SRC); b1 = gen_fhostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_fhostop(eaddr, Q_SRC); b1 = gen_fhostop(eaddr, Q_DST); gen_or(b0, b1); return b1; } abort(); /* NOTREACHED */ } /* * Like gen_ehostop, but for DLT_IEEE802 (Token Ring) */ static struct block *gen_thostop(eaddr, dir) register const u_char *eaddr; register int dir; { register struct block *b0, *b1; switch (dir) { case Q_SRC: return gen_bcmp(OR_LINK, 8, 6, eaddr); case Q_DST: return gen_bcmp(OR_LINK, 2, 6, eaddr); case Q_AND: b0 = gen_thostop(eaddr, Q_SRC); b1 = gen_thostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_thostop(eaddr, Q_SRC); b1 = gen_thostop(eaddr, Q_DST); gen_or(b0, b1); return b1; } abort(); /* NOTREACHED */ } /* * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and * various 802.11 + radio headers. */ static struct block *gen_wlanhostop(eaddr, dir) register const u_char *eaddr; register int dir; { register struct block *b0, *b1, *b2; register struct slist *s; #ifdef ENABLE_WLAN_FILTERING_PATCH /* * GV 20070613 * We need to disable the optimizer because the optimizer is buggy * and wipes out some LD instructions generated by the below * code to validate the Frame Control bits */ no_optimize = 1; #endif /* ENABLE_WLAN_FILTERING_PATCH */ switch (dir) { case Q_SRC: /* * Oh, yuk. * * For control frames, there is no SA. * * For management frames, SA is at an * offset of 10 from the beginning of * the packet. * * For data frames, SA is at an offset * of 10 from the beginning of the packet * if From DS is clear, at an offset of * 16 from the beginning of the packet * if From DS is set and To DS is clear, * and an offset of 24 from the beginning * of the packet if From DS is set and To DS * is set. */ /* * Generate the tests to be done for data frames * with From DS set. * * First, check for To DS set, i.e. check "link[1] & 0x01". */ s = gen_load_a(OR_LINK, 1, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x01; /* To DS */ b1->stmts = s; /* * If To DS is set, the SA is at 24. */ b0 = gen_bcmp(OR_LINK, 24, 6, eaddr); gen_and(b1, b0); /* * Now, check for To DS not set, i.e. check * "!(link[1] & 0x01)". */ s = gen_load_a(OR_LINK, 1, BPF_B); b2 = new_block(JMP(BPF_JSET)); b2->s.k = 0x01; /* To DS */ b2->stmts = s; gen_not(b2); /* * If To DS is not set, the SA is at 16. */ b1 = gen_bcmp(OR_LINK, 16, 6, eaddr); gen_and(b2, b1); /* * Now OR together the last two checks. That gives * the complete set of checks for data frames with * From DS set. */ gen_or(b1, b0); /* * Now check for From DS being set, and AND that with * the ORed-together checks. */ s = gen_load_a(OR_LINK, 1, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x02; /* From DS */ b1->stmts = s; gen_and(b1, b0); /* * Now check for data frames with From DS not set. */ s = gen_load_a(OR_LINK, 1, BPF_B); b2 = new_block(JMP(BPF_JSET)); b2->s.k = 0x02; /* From DS */ b2->stmts = s; gen_not(b2); /* * If From DS isn't set, the SA is at 10. */ b1 = gen_bcmp(OR_LINK, 10, 6, eaddr); gen_and(b2, b1); /* * Now OR together the checks for data frames with * From DS not set and for data frames with From DS * set; that gives the checks done for data frames. */ gen_or(b1, b0); /* * Now check for a data frame. * I.e, check "link[0] & 0x08". */ s = gen_load_a(OR_LINK, 0, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x08; b1->stmts = s; /* * AND that with the checks done for data frames. */ gen_and(b1, b0); /* * If the high-order bit of the type value is 0, this * is a management frame. * I.e, check "!(link[0] & 0x08)". */ s = gen_load_a(OR_LINK, 0, BPF_B); b2 = new_block(JMP(BPF_JSET)); b2->s.k = 0x08; b2->stmts = s; gen_not(b2); /* * For management frames, the SA is at 10. */ b1 = gen_bcmp(OR_LINK, 10, 6, eaddr); gen_and(b2, b1); /* * OR that with the checks done for data frames. * That gives the checks done for management and * data frames. */ gen_or(b1, b0); /* * If the low-order bit of the type value is 1, * this is either a control frame or a frame * with a reserved type, and thus not a * frame with an SA. * * I.e., check "!(link[0] & 0x04)". */ s = gen_load_a(OR_LINK, 0, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x04; b1->stmts = s; gen_not(b1); /* * AND that with the checks for data and management * frames. */ gen_and(b1, b0); return b0; case Q_DST: /* * Oh, yuk. * * For control frames, there is no DA. * * For management frames, DA is at an * offset of 4 from the beginning of * the packet. * * For data frames, DA is at an offset * of 4 from the beginning of the packet * if To DS is clear and at an offset of * 16 from the beginning of the packet * if To DS is set. */ /* * Generate the tests to be done for data frames. * * First, check for To DS set, i.e. "link[1] & 0x01". */ s = gen_load_a(OR_LINK, 1, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x01; /* To DS */ b1->stmts = s; /* * If To DS is set, the DA is at 16. */ b0 = gen_bcmp(OR_LINK, 16, 6, eaddr); gen_and(b1, b0); /* * Now, check for To DS not set, i.e. check * "!(link[1] & 0x01)". */ s = gen_load_a(OR_LINK, 1, BPF_B); b2 = new_block(JMP(BPF_JSET)); b2->s.k = 0x01; /* To DS */ b2->stmts = s; gen_not(b2); /* * If To DS is not set, the DA is at 4. */ b1 = gen_bcmp(OR_LINK, 4, 6, eaddr); gen_and(b2, b1); /* * Now OR together the last two checks. That gives * the complete set of checks for data frames. */ gen_or(b1, b0); /* * Now check for a data frame. * I.e, check "link[0] & 0x08". */ s = gen_load_a(OR_LINK, 0, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x08; b1->stmts = s; /* * AND that with the checks done for data frames. */ gen_and(b1, b0); /* * If the high-order bit of the type value is 0, this * is a management frame. * I.e, check "!(link[0] & 0x08)". */ s = gen_load_a(OR_LINK, 0, BPF_B); b2 = new_block(JMP(BPF_JSET)); b2->s.k = 0x08; b2->stmts = s; gen_not(b2); /* * For management frames, the DA is at 4. */ b1 = gen_bcmp(OR_LINK, 4, 6, eaddr); gen_and(b2, b1); /* * OR that with the checks done for data frames. * That gives the checks done for management and * data frames. */ gen_or(b1, b0); /* * If the low-order bit of the type value is 1, * this is either a control frame or a frame * with a reserved type, and thus not a * frame with an SA. * * I.e., check "!(link[0] & 0x04)". */ s = gen_load_a(OR_LINK, 0, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x04; b1->stmts = s; gen_not(b1); /* * AND that with the checks for data and management * frames. */ gen_and(b1, b0); return b0; /* * XXX - add RA, TA, and BSSID keywords? */ case Q_ADDR1: return (gen_bcmp(OR_LINK, 4, 6, eaddr)); case Q_ADDR2: /* * Not present in CTS or ACK control frames. */ b0 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_TYPE_CTL, IEEE80211_FC0_TYPE_MASK); gen_not(b0); b1 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS, IEEE80211_FC0_SUBTYPE_MASK); gen_not(b1); b2 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK, IEEE80211_FC0_SUBTYPE_MASK); gen_not(b2); gen_and(b1, b2); gen_or(b0, b2); b1 = gen_bcmp(OR_LINK, 10, 6, eaddr); gen_and(b2, b1); return b1; case Q_ADDR3: /* * Not present in control frames. */ b0 = gen_mcmp(OR_LINK, 0, BPF_B, IEEE80211_FC0_TYPE_CTL, IEEE80211_FC0_TYPE_MASK); gen_not(b0); b1 = gen_bcmp(OR_LINK, 16, 6, eaddr); gen_and(b0, b1); return b1; case Q_ADDR4: /* * Present only if the direction mask has both "From DS" * and "To DS" set. Neither control frames nor management * frames should have both of those set, so we don't * check the frame type. */ b0 = gen_mcmp(OR_LINK, 1, BPF_B, IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK); b1 = gen_bcmp(OR_LINK, 24, 6, eaddr); gen_and(b0, b1); return b1; case Q_AND: b0 = gen_wlanhostop(eaddr, Q_SRC); b1 = gen_wlanhostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_wlanhostop(eaddr, Q_SRC); b1 = gen_wlanhostop(eaddr, Q_DST); gen_or(b0, b1); return b1; } abort(); /* NOTREACHED */ } /* * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel. * (We assume that the addresses are IEEE 48-bit MAC addresses, * as the RFC states.) */ static struct block *gen_ipfchostop(eaddr, dir) register const u_char *eaddr; register int dir; { register struct block *b0, *b1; switch (dir) { case Q_SRC: return gen_bcmp(OR_LINK, 10, 6, eaddr); case Q_DST: return gen_bcmp(OR_LINK, 2, 6, eaddr); case Q_AND: b0 = gen_ipfchostop(eaddr, Q_SRC); b1 = gen_ipfchostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_ipfchostop(eaddr, Q_SRC); b1 = gen_ipfchostop(eaddr, Q_DST); gen_or(b0, b1); return b1; } abort(); /* NOTREACHED */ } /* * This is quite tricky because there may be pad bytes in front of the * DECNET header, and then there are two possible data packet formats that * carry both src and dst addresses, plus 5 packet types in a format that * carries only the src node, plus 2 types that use a different format and * also carry just the src node. * * Yuck. * * Instead of doing those all right, we just look for data packets with * 0 or 1 bytes of padding. If you want to look at other packets, that * will require a lot more hacking. * * To add support for filtering on DECNET "areas" (network numbers) * one would want to add a "mask" argument to this routine. That would * make the filter even more inefficient, although one could be clever * and not generate masking instructions if the mask is 0xFFFF. */ static struct block *gen_dnhostop(addr, dir) bpf_u_int32 addr; int dir; { struct block *b0, *b1, *b2, *tmp; u_int offset_lh; /* offset if long header is received */ u_int offset_sh; /* offset if short header is received */ switch (dir) { case Q_DST: offset_sh = 1; /* follows flags */ offset_lh = 7; /* flgs,darea,dsubarea,HIORD */ break; case Q_SRC: offset_sh = 3; /* follows flags, dstnode */ offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */ break; case Q_AND: /* Inefficient because we do our Calvinball dance twice */ b0 = gen_dnhostop(addr, Q_SRC); b1 = gen_dnhostop(addr, Q_DST); gen_and(b0, b1); return b1; case Q_OR: case Q_DEFAULT: /* Inefficient because we do our Calvinball dance twice */ b0 = gen_dnhostop(addr, Q_SRC); b1 = gen_dnhostop(addr, Q_DST); gen_or(b0, b1); return b1; case Q_ISO: bpf_error("ISO host filtering not implemented"); default: abort(); } b0 = gen_linktype(ETHERTYPE_DN); /* Check for pad = 1, long header case */ tmp = gen_mcmp(OR_NET, 2, BPF_H, (bpf_int32) ntohs(0x0681), (bpf_int32) ntohs(0x07FF)); b1 = gen_cmp(OR_NET, 2 + 1 + offset_lh, BPF_H, (bpf_int32) ntohs((u_short) addr)); gen_and(tmp, b1); /* Check for pad = 0, long header case */ tmp = gen_mcmp(OR_NET, 2, BPF_B, (bpf_int32) 0x06, (bpf_int32) 0x7); b2 = gen_cmp(OR_NET, 2 + offset_lh, BPF_H, (bpf_int32) ntohs((u_short) addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Check for pad = 1, short header case */ tmp = gen_mcmp(OR_NET, 2, BPF_H, (bpf_int32) ntohs(0x0281), (bpf_int32) ntohs(0x07FF)); b2 = gen_cmp(OR_NET, 2 + 1 + offset_sh, BPF_H, (bpf_int32) ntohs((u_short) addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Check for pad = 0, short header case */ tmp = gen_mcmp(OR_NET, 2, BPF_B, (bpf_int32) 0x02, (bpf_int32) 0x7); b2 = gen_cmp(OR_NET, 2 + offset_sh, BPF_H, (bpf_int32) ntohs((u_short) addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Combine with test for linktype */ gen_and(b0, b1); return b1; } /* * Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets; * test the bottom-of-stack bit, and then check the version number * field in the IP header. */ static struct block *gen_mpls_linktype(proto) int proto; { struct block *b0, *b1; switch (proto) { case Q_IP: /* match the bottom-of-stack bit */ b0 = gen_mcmp(OR_NET, -2, BPF_B, 0x01, 0x01); /* match the IPv4 version number */ b1 = gen_mcmp(OR_NET, 0, BPF_B, 0x40, 0xf0); gen_and(b0, b1); return b1; case Q_IPV6: /* match the bottom-of-stack bit */ b0 = gen_mcmp(OR_NET, -2, BPF_B, 0x01, 0x01); /* match the IPv4 version number */ b1 = gen_mcmp(OR_NET, 0, BPF_B, 0x60, 0xf0); gen_and(b0, b1); return b1; default: abort(); } } static struct block *gen_host(addr, mask, proto, dir, type) bpf_u_int32 addr; bpf_u_int32 mask; int proto; int dir; int type; { struct block *b0, *b1; const char *typestr; if (type == Q_NET) typestr = "net"; else typestr = "host"; switch (proto) { case Q_DEFAULT: b0 = gen_host(addr, mask, Q_IP, dir, type); /* * Only check for non-IPv4 addresses if we're not * checking MPLS-encapsulated packets. */ if (label_stack_depth == 0) { b1 = gen_host(addr, mask, Q_ARP, dir, type); gen_or(b0, b1); b0 = gen_host(addr, mask, Q_RARP, dir, type); gen_or(b1, b0); } return b0; case Q_IP: return gen_hostop(addr, mask, dir, ETHERTYPE_IP, 12, 16); case Q_RARP: return gen_hostop(addr, mask, dir, ETHERTYPE_REVARP, 14, 24); case Q_ARP: return gen_hostop(addr, mask, dir, ETHERTYPE_ARP, 14, 24); case Q_TCP: bpf_error("'tcp' modifier applied to %s", typestr); case Q_SCTP: bpf_error("'sctp' modifier applied to %s", typestr); case Q_UDP: bpf_error("'udp' modifier applied to %s", typestr); case Q_ICMP: bpf_error("'icmp' modifier applied to %s", typestr); case Q_IGMP: bpf_error("'igmp' modifier applied to %s", typestr); case Q_IGRP: bpf_error("'igrp' modifier applied to %s", typestr); case Q_PIM: bpf_error("'pim' modifier applied to %s", typestr); case Q_VRRP: bpf_error("'vrrp' modifier applied to %s", typestr); case Q_ATALK: bpf_error("ATALK host filtering not implemented"); case Q_AARP: bpf_error("AARP host filtering not implemented"); case Q_DECNET: return gen_dnhostop(addr, dir); case Q_SCA: bpf_error("SCA host filtering not implemented"); case Q_LAT: bpf_error("LAT host filtering not implemented"); case Q_MOPDL: bpf_error("MOPDL host filtering not implemented"); case Q_MOPRC: bpf_error("MOPRC host filtering not implemented"); #ifdef INET6 case Q_IPV6: bpf_error("'ip6' modifier applied to ip host"); case Q_ICMPV6: bpf_error("'icmp6' modifier applied to %s", typestr); #endif /* INET6 */ case Q_AH: bpf_error("'ah' modifier applied to %s", typestr); case Q_ESP: bpf_error("'esp' modifier applied to %s", typestr); case Q_ISO: bpf_error("ISO host filtering not implemented"); case Q_ESIS: bpf_error("'esis' modifier applied to %s", typestr); case Q_ISIS: bpf_error("'isis' modifier applied to %s", typestr); case Q_CLNP: bpf_error("'clnp' modifier applied to %s", typestr); case Q_STP: bpf_error("'stp' modifier applied to %s", typestr); case Q_IPX: bpf_error("IPX host filtering not implemented"); case Q_NETBEUI: bpf_error("'netbeui' modifier applied to %s", typestr); case Q_RADIO: bpf_error("'radio' modifier applied to %s", typestr); default: abort(); } /* NOTREACHED */ } #ifdef INET6 static struct block *gen_host6(addr, mask, proto, dir, type) struct in6_addr *addr; struct in6_addr *mask; int proto; int dir; int type; { const char *typestr; if (type == Q_NET) typestr = "net"; else typestr = "host"; switch (proto) { case Q_DEFAULT: return gen_host6(addr, mask, Q_IPV6, dir, type); case Q_IP: bpf_error("'ip' modifier applied to ip6 %s", typestr); case Q_RARP: bpf_error("'rarp' modifier applied to ip6 %s", typestr); case Q_ARP: bpf_error("'arp' modifier applied to ip6 %s", typestr); case Q_SCTP: bpf_error("'sctp' modifier applied to %s", typestr); case Q_TCP: bpf_error("'tcp' modifier applied to %s", typestr); case Q_UDP: bpf_error("'udp' modifier applied to %s", typestr); case Q_ICMP: bpf_error("'icmp' modifier applied to %s", typestr); case Q_IGMP: bpf_error("'igmp' modifier applied to %s", typestr); case Q_IGRP: bpf_error("'igrp' modifier applied to %s", typestr); case Q_PIM: bpf_error("'pim' modifier applied to %s", typestr); case Q_VRRP: bpf_error("'vrrp' modifier applied to %s", typestr); case Q_ATALK: bpf_error("ATALK host filtering not implemented"); case Q_AARP: bpf_error("AARP host filtering not implemented"); case Q_DECNET: bpf_error("'decnet' modifier applied to ip6 %s", typestr); case Q_SCA: bpf_error("SCA host filtering not implemented"); case Q_LAT: bpf_error("LAT host filtering not implemented"); case Q_MOPDL: bpf_error("MOPDL host filtering not implemented"); case Q_MOPRC: bpf_error("MOPRC host filtering not implemented"); case Q_IPV6: return gen_hostop6(addr, mask, dir, ETHERTYPE_IPV6, 8, 24); case Q_ICMPV6: bpf_error("'icmp6' modifier applied to %s", typestr); case Q_AH: bpf_error("'ah' modifier applied to %s", typestr); case Q_ESP: bpf_error("'esp' modifier applied to %s", typestr); case Q_ISO: bpf_error("ISO host filtering not implemented"); case Q_ESIS: bpf_error("'esis' modifier applied to %s", typestr); case Q_ISIS: bpf_error("'isis' modifier applied to %s", typestr); case Q_CLNP: bpf_error("'clnp' modifier applied to %s", typestr); case Q_STP: bpf_error("'stp' modifier applied to %s", typestr); case Q_IPX: bpf_error("IPX host filtering not implemented"); case Q_NETBEUI: bpf_error("'netbeui' modifier applied to %s", typestr); case Q_RADIO: bpf_error("'radio' modifier applied to %s", typestr); default: abort(); } /* NOTREACHED */ } #endif /*INET6 */ #ifndef INET6 static struct block *gen_gateway(eaddr, alist, proto, dir) const u_char *eaddr; bpf_u_int32 **alist; int proto; int dir; { struct block *b0, *b1, *tmp; if (dir != 0) bpf_error("direction applied to 'gateway'"); switch (proto) { case Q_DEFAULT: case Q_IP: case Q_ARP: case Q_RARP: switch (linktype) { case DLT_EN10MB: b0 = gen_ehostop(eaddr, Q_OR); break; case DLT_FDDI: b0 = gen_fhostop(eaddr, Q_OR); break; case DLT_IEEE802: b0 = gen_thostop(eaddr, Q_OR); break; case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: b0 = gen_wlanhostop(eaddr, Q_OR); break; case DLT_SUNATM: if (!is_lane) bpf_error ("'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); /* * Check that the packet doesn't begin with an * LE Control marker. (We've already generated * a test for LANE.) */ b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00); gen_not(b1); /* * Now check the MAC address. */ b0 = gen_ehostop(eaddr, Q_OR); gen_and(b1, b0); break; case DLT_IP_OVER_FC: b0 = gen_ipfchostop(eaddr, Q_OR); break; default: bpf_error ("'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); } b1 = gen_host(**alist++, 0xffffffff, proto, Q_OR, Q_HOST); while (*alist) { tmp = gen_host(**alist++, 0xffffffff, proto, Q_OR, Q_HOST); gen_or(b1, tmp); b1 = tmp; } gen_not(b1); gen_and(b0, b1); return b1; } bpf_error("illegal modifier of 'gateway'"); /* NOTREACHED */ } #endif struct block *gen_proto_abbrev(proto) int proto; { struct block *b0; struct block *b1; switch (proto) { case Q_SCTP: b1 = gen_proto(IPPROTO_SCTP, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_SCTP, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; case Q_TCP: b1 = gen_proto(IPPROTO_TCP, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_TCP, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; case Q_UDP: b1 = gen_proto(IPPROTO_UDP, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_UDP, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; case Q_ICMP: b1 = gen_proto(IPPROTO_ICMP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_IGMP #define IPPROTO_IGMP 2 #endif case Q_IGMP: b1 = gen_proto(IPPROTO_IGMP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_IGRP #define IPPROTO_IGRP 9 #endif case Q_IGRP: b1 = gen_proto(IPPROTO_IGRP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_PIM #define IPPROTO_PIM 103 #endif case Q_PIM: b1 = gen_proto(IPPROTO_PIM, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_PIM, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; #ifndef IPPROTO_VRRP #define IPPROTO_VRRP 112 #endif case Q_VRRP: b1 = gen_proto(IPPROTO_VRRP, Q_IP, Q_DEFAULT); break; case Q_IP: b1 = gen_linktype(ETHERTYPE_IP); break; case Q_ARP: b1 = gen_linktype(ETHERTYPE_ARP); break; case Q_RARP: b1 = gen_linktype(ETHERTYPE_REVARP); break; case Q_LINK: bpf_error("link layer applied in wrong context"); case Q_ATALK: b1 = gen_linktype(ETHERTYPE_ATALK); break; case Q_AARP: b1 = gen_linktype(ETHERTYPE_AARP); break; case Q_DECNET: b1 = gen_linktype(ETHERTYPE_DN); break; case Q_SCA: b1 = gen_linktype(ETHERTYPE_SCA); break; case Q_LAT: b1 = gen_linktype(ETHERTYPE_LAT); break; case Q_MOPDL: b1 = gen_linktype(ETHERTYPE_MOPDL); break; case Q_MOPRC: b1 = gen_linktype(ETHERTYPE_MOPRC); break; #ifdef INET6 case Q_IPV6: b1 = gen_linktype(ETHERTYPE_IPV6); break; #ifndef IPPROTO_ICMPV6 #define IPPROTO_ICMPV6 58 #endif case Q_ICMPV6: b1 = gen_proto(IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT); break; #endif /* INET6 */ #ifndef IPPROTO_AH #define IPPROTO_AH 51 #endif case Q_AH: b1 = gen_proto(IPPROTO_AH, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_AH, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; #ifndef IPPROTO_ESP #define IPPROTO_ESP 50 #endif case Q_ESP: b1 = gen_proto(IPPROTO_ESP, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_ESP, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; case Q_ISO: b1 = gen_linktype(LLCSAP_ISONS); break; case Q_ESIS: b1 = gen_proto(ISO9542_ESIS, Q_ISO, Q_DEFAULT); break; case Q_ISIS: b1 = gen_proto(ISO10589_ISIS, Q_ISO, Q_DEFAULT); break; case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */ b0 = gen_proto(ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT); b1 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */ gen_or(b0, b1); b0 = gen_proto(ISIS_L1_LSP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */ b0 = gen_proto(ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT); b1 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */ gen_or(b0, b1); b0 = gen_proto(ISIS_L2_LSP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */ b0 = gen_proto(ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT); b1 = gen_proto(ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_LSP: b0 = gen_proto(ISIS_L1_LSP, Q_ISIS, Q_DEFAULT); b1 = gen_proto(ISIS_L2_LSP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_SNP: b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); b1 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); b0 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_CSNP: b0 = gen_proto(ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT); b1 = gen_proto(ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_ISIS_PSNP: b0 = gen_proto(ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT); b1 = gen_proto(ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT); gen_or(b0, b1); break; case Q_CLNP: b1 = gen_proto(ISO8473_CLNP, Q_ISO, Q_DEFAULT); break; case Q_STP: b1 = gen_linktype(LLCSAP_8021D); break; case Q_IPX: b1 = gen_linktype(LLCSAP_IPX); break; case Q_NETBEUI: b1 = gen_linktype(LLCSAP_NETBEUI); break; case Q_RADIO: bpf_error("'radio' is not a valid protocol type"); default: abort(); } return b1; } static struct block *gen_ipfrag() { struct slist *s; struct block *b; /* not ip frag */ s = gen_load_a(OR_NET, 6, BPF_H); b = new_block(JMP(BPF_JSET)); b->s.k = 0x1fff; b->stmts = s; gen_not(b); return b; } /* * Generate a comparison to a port value in the transport-layer header * at the specified offset from the beginning of that header. * * XXX - this handles a variable-length prefix preceding the link-layer * header, such as the radiotap or AVS radio prefix, but doesn't handle * variable-length link-layer headers (such as Token Ring or 802.11 * headers). */ static struct block *gen_portatom(off, v) int off; bpf_int32 v; { return gen_cmp(OR_TRAN_IPV4, off, BPF_H, v); } #ifdef INET6 static struct block *gen_portatom6(off, v) int off; bpf_int32 v; { return gen_cmp(OR_TRAN_IPV6, off, BPF_H, v); } #endif /*INET6 */ struct block *gen_portop(port, proto, dir) int port, proto, dir; { struct block *b0, *b1, *tmp; /* ip proto 'proto' */ tmp = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32) proto); b0 = gen_ipfrag(); gen_and(tmp, b0); switch (dir) { case Q_SRC: b1 = gen_portatom(0, (bpf_int32) port); break; case Q_DST: b1 = gen_portatom(2, (bpf_int32) port); break; case Q_OR: case Q_DEFAULT: tmp = gen_portatom(0, (bpf_int32) port); b1 = gen_portatom(2, (bpf_int32) port); gen_or(tmp, b1); break; case Q_AND: tmp = gen_portatom(0, (bpf_int32) port); b1 = gen_portatom(2, (bpf_int32) port); gen_and(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block *gen_port(port, ip_proto, dir) int port; int ip_proto; int dir; { struct block *b0, *b1, *tmp; /* * ether proto ip * * For FDDI, RFC 1188 says that SNAP encapsulation is used, * not LLC encapsulation with LLCSAP_IP. * * For IEEE 802 networks - which includes 802.5 token ring * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042 * says that SNAP encapsulation is used, not LLC encapsulation * with LLCSAP_IP. * * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and * RFC 2225 say that SNAP encapsulation is used, not LLC * encapsulation with LLCSAP_IP. * * So we always check for ETHERTYPE_IP. */ b0 = gen_linktype(ETHERTYPE_IP); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: case IPPROTO_SCTP: b1 = gen_portop(port, ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portop(port, IPPROTO_TCP, dir); b1 = gen_portop(port, IPPROTO_UDP, dir); gen_or(tmp, b1); tmp = gen_portop(port, IPPROTO_SCTP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } #ifdef INET6 struct block *gen_portop6(port, proto, dir) int port, proto, dir; { struct block *b0, *b1, *tmp; /* ip6 proto 'proto' */ b0 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32) proto); switch (dir) { case Q_SRC: b1 = gen_portatom6(0, (bpf_int32) port); break; case Q_DST: b1 = gen_portatom6(2, (bpf_int32) port); break; case Q_OR: case Q_DEFAULT: tmp = gen_portatom6(0, (bpf_int32) port); b1 = gen_portatom6(2, (bpf_int32) port); gen_or(tmp, b1); break; case Q_AND: tmp = gen_portatom6(0, (bpf_int32) port); b1 = gen_portatom6(2, (bpf_int32) port); gen_and(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block *gen_port6(port, ip_proto, dir) int port; int ip_proto; int dir; { struct block *b0, *b1, *tmp; /* link proto ip6 */ b0 = gen_linktype(ETHERTYPE_IPV6); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: case IPPROTO_SCTP: b1 = gen_portop6(port, ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portop6(port, IPPROTO_TCP, dir); b1 = gen_portop6(port, IPPROTO_UDP, dir); gen_or(tmp, b1); tmp = gen_portop6(port, IPPROTO_SCTP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } #endif /* INET6 */ /* gen_portrange code */ static struct block *gen_portrangeatom(off, v1, v2) int off; bpf_int32 v1, v2; { struct block *b1, *b2; if (v1 > v2) { /* * Reverse the order of the ports, so v1 is the lower one. */ bpf_int32 vtemp; vtemp = v1; v1 = v2; v2 = vtemp; } b1 = gen_cmp_ge(OR_TRAN_IPV4, off, BPF_H, v1); b2 = gen_cmp_le(OR_TRAN_IPV4, off, BPF_H, v2); gen_and(b1, b2); return b2; } struct block *gen_portrangeop(port1, port2, proto, dir) int port1, port2; int proto; int dir; { struct block *b0, *b1, *tmp; /* ip proto 'proto' */ tmp = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32) proto); b0 = gen_ipfrag(); gen_and(tmp, b0); switch (dir) { case Q_SRC: b1 = gen_portrangeatom(0, (bpf_int32) port1, (bpf_int32) port2); break; case Q_DST: b1 = gen_portrangeatom(2, (bpf_int32) port1, (bpf_int32) port2); break; case Q_OR: case Q_DEFAULT: tmp = gen_portrangeatom(0, (bpf_int32) port1, (bpf_int32) port2); b1 = gen_portrangeatom(2, (bpf_int32) port1, (bpf_int32) port2); gen_or(tmp, b1); break; case Q_AND: tmp = gen_portrangeatom(0, (bpf_int32) port1, (bpf_int32) port2); b1 = gen_portrangeatom(2, (bpf_int32) port1, (bpf_int32) port2); gen_and(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block *gen_portrange(port1, port2, ip_proto, dir) int port1, port2; int ip_proto; int dir; { struct block *b0, *b1, *tmp; /* link proto ip */ b0 = gen_linktype(ETHERTYPE_IP); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: case IPPROTO_SCTP: b1 = gen_portrangeop(port1, port2, ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portrangeop(port1, port2, IPPROTO_TCP, dir); b1 = gen_portrangeop(port1, port2, IPPROTO_UDP, dir); gen_or(tmp, b1); tmp = gen_portrangeop(port1, port2, IPPROTO_SCTP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } #ifdef INET6 static struct block *gen_portrangeatom6(off, v1, v2) int off; bpf_int32 v1, v2; { struct block *b1, *b2; if (v1 > v2) { /* * Reverse the order of the ports, so v1 is the lower one. */ bpf_int32 vtemp; vtemp = v1; v1 = v2; v2 = vtemp; } b1 = gen_cmp_ge(OR_TRAN_IPV6, off, BPF_H, v1); b2 = gen_cmp_le(OR_TRAN_IPV6, off, BPF_H, v2); gen_and(b1, b2); return b2; } struct block *gen_portrangeop6(port1, port2, proto, dir) int port1, port2; int proto; int dir; { struct block *b0, *b1, *tmp; /* ip6 proto 'proto' */ b0 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32) proto); switch (dir) { case Q_SRC: b1 = gen_portrangeatom6(0, (bpf_int32) port1, (bpf_int32) port2); break; case Q_DST: b1 = gen_portrangeatom6(2, (bpf_int32) port1, (bpf_int32) port2); break; case Q_OR: case Q_DEFAULT: tmp = gen_portrangeatom6(0, (bpf_int32) port1, (bpf_int32) port2); b1 = gen_portrangeatom6(2, (bpf_int32) port1, (bpf_int32) port2); gen_or(tmp, b1); break; case Q_AND: tmp = gen_portrangeatom6(0, (bpf_int32) port1, (bpf_int32) port2); b1 = gen_portrangeatom6(2, (bpf_int32) port1, (bpf_int32) port2); gen_and(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block *gen_portrange6(port1, port2, ip_proto, dir) int port1, port2; int ip_proto; int dir; { struct block *b0, *b1, *tmp; /* link proto ip6 */ b0 = gen_linktype(ETHERTYPE_IPV6); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: case IPPROTO_SCTP: b1 = gen_portrangeop6(port1, port2, ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portrangeop6(port1, port2, IPPROTO_TCP, dir); b1 = gen_portrangeop6(port1, port2, IPPROTO_UDP, dir); gen_or(tmp, b1); tmp = gen_portrangeop6(port1, port2, IPPROTO_SCTP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } #endif /* INET6 */ static int lookup_proto(name, proto) register const char *name; register int proto; { register int v; switch (proto) { case Q_DEFAULT: case Q_IP: case Q_IPV6: v = pcap_nametoproto(name); if (v == PROTO_UNDEF) bpf_error("unknown ip proto '%s'", name); break; case Q_LINK: /* XXX should look up h/w protocol type based on linktype */ v = pcap_nametoeproto(name); if (v == PROTO_UNDEF) { v = pcap_nametollc(name); if (v == PROTO_UNDEF) bpf_error("unknown ether proto '%s'", name); } break; case Q_ISO: if (strcmp(name, "esis") == 0) v = ISO9542_ESIS; else if (strcmp(name, "isis") == 0) v = ISO10589_ISIS; else if (strcmp(name, "clnp") == 0) v = ISO8473_CLNP; else bpf_error("unknown osi proto '%s'", name); break; default: v = PROTO_UNDEF; break; } return v; } static struct block *gen_protochain(v, proto, dir) int v; int proto; int dir; { #ifdef NO_PROTOCHAIN return gen_proto(v, proto, dir); #else struct block *b0, *b; struct slist *s[100]; int fix2, fix3, fix4, fix5; int ahcheck, again, end; int i, max; int reg2 = alloc_reg(); memset(s, 0, sizeof(s)); fix2 = fix3 = fix4 = fix5 = 0; switch (proto) { case Q_IP: case Q_IPV6: break; case Q_DEFAULT: b0 = gen_protochain(v, Q_IP, dir); b = gen_protochain(v, Q_IPV6, dir); gen_or(b0, b); return b; default: bpf_error("bad protocol applied for 'protochain'"); /*NOTREACHED*/} /* * We don't handle variable-length prefixes before the link-layer * header, or variable-length link-layer headers, here yet. * We might want to add BPF instructions to do the protochain * work, to simplify that and, on platforms that have a BPF * interpreter with the new instructions, let the filtering * be done in the kernel. (We already require a modified BPF * engine to do the protochain stuff, to support backward * branches, and backward branch support is unlikely to appear * in kernel BPF engines.) */ switch (linktype) { case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: bpf_error("'protochain' not supported with 802.11"); } no_optimize = 1; /*this code is not compatible with optimzer yet */ /* * s[0] is a dummy entry to protect other BPF insn from damage * by s[fix] = foo with uninitialized variable "fix". It is somewhat * hard to find interdependency made by jump table fixup. */ i = 0; s[i] = new_stmt(0); /*dummy */ i++; switch (proto) { case Q_IP: b0 = gen_linktype(ETHERTYPE_IP); /* A = ip->ip_p */ s[i] = new_stmt(BPF_LD | BPF_ABS | BPF_B); s[i]->s.k = off_macpl + off_nl + 9; i++; /* X = ip->ip_hl << 2 */ s[i] = new_stmt(BPF_LDX | BPF_MSH | BPF_B); s[i]->s.k = off_macpl + off_nl; i++; break; #ifdef INET6 case Q_IPV6: b0 = gen_linktype(ETHERTYPE_IPV6); /* A = ip6->ip_nxt */ s[i] = new_stmt(BPF_LD | BPF_ABS | BPF_B); s[i]->s.k = off_macpl + off_nl + 6; i++; /* X = sizeof(struct ip6_hdr) */ s[i] = new_stmt(BPF_LDX | BPF_IMM); s[i]->s.k = 40; i++; break; #endif default: bpf_error("unsupported proto to gen_protochain"); /*NOTREACHED*/} /* again: if (A == v) goto end; else fall through; */ again = i; s[i] = new_stmt(BPF_JMP | BPF_JEQ | BPF_K); s[i]->s.k = v; s[i]->s.jt = NULL; /*later */ s[i]->s.jf = NULL; /*update in next stmt */ fix5 = i; i++; #ifndef IPPROTO_NONE #define IPPROTO_NONE 59 #endif /* if (A == IPPROTO_NONE) goto end */ s[i] = new_stmt(BPF_JMP | BPF_JEQ | BPF_K); s[i]->s.jt = NULL; /*later */ s[i]->s.jf = NULL; /*update in next stmt */ s[i]->s.k = IPPROTO_NONE; s[fix5]->s.jf = s[i]; fix2 = i; i++; #ifdef INET6 if (proto == Q_IPV6) { int v6start, v6end, v6advance, j; v6start = i; /* if (A == IPPROTO_HOPOPTS) goto v6advance */ s[i] = new_stmt(BPF_JMP | BPF_JEQ | BPF_K); s[i]->s.jt = NULL; /*later */ s[i]->s.jf = NULL; /*update in next stmt */ s[i]->s.k = IPPROTO_HOPOPTS; s[fix2]->s.jf = s[i]; i++; /* if (A == IPPROTO_DSTOPTS) goto v6advance */ s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP | BPF_JEQ | BPF_K); s[i]->s.jt = NULL; /*later */ s[i]->s.jf = NULL; /*update in next stmt */ s[i]->s.k = IPPROTO_DSTOPTS; i++; /* if (A == IPPROTO_ROUTING) goto v6advance */ s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP | BPF_JEQ | BPF_K); s[i]->s.jt = NULL; /*later */ s[i]->s.jf = NULL; /*update in next stmt */ s[i]->s.k = IPPROTO_ROUTING; i++; /* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */ s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP | BPF_JEQ | BPF_K); s[i]->s.jt = NULL; /*later */ s[i]->s.jf = NULL; /*later */ s[i]->s.k = IPPROTO_FRAGMENT; fix3 = i; v6end = i; i++; /* v6advance: */ v6advance = i; /* * in short, * A = P[X]; * X = X + (P[X + 1] + 1) * 8; */ /* A = X */ s[i] = new_stmt(BPF_MISC | BPF_TXA); i++; /* A = P[X + packet head] */ s[i] = new_stmt(BPF_LD | BPF_IND | BPF_B); s[i]->s.k = off_macpl + off_nl; i++; /* MEM[reg2] = A */ s[i] = new_stmt(BPF_ST); s[i]->s.k = reg2; i++; /* A = X */ s[i] = new_stmt(BPF_MISC | BPF_TXA); i++; /* A += 1 */ s[i] = new_stmt(BPF_ALU | BPF_ADD | BPF_K); s[i]->s.k = 1; i++; /* X = A */ s[i] = new_stmt(BPF_MISC | BPF_TAX); i++; /* A = P[X + packet head]; */ s[i] = new_stmt(BPF_LD | BPF_IND | BPF_B); s[i]->s.k = off_macpl + off_nl; i++; /* A += 1 */ s[i] = new_stmt(BPF_ALU | BPF_ADD | BPF_K); s[i]->s.k = 1; i++; /* A *= 8 */ s[i] = new_stmt(BPF_ALU | BPF_MUL | BPF_K); s[i]->s.k = 8; i++; /* X = A; */ s[i] = new_stmt(BPF_MISC | BPF_TAX); i++; /* A = MEM[reg2] */ s[i] = new_stmt(BPF_LD | BPF_MEM); s[i]->s.k = reg2; i++; /* goto again; (must use BPF_JA for backward jump) */ s[i] = new_stmt(BPF_JMP | BPF_JA); s[i]->s.k = again - i - 1; s[i - 1]->s.jf = s[i]; i++; /* fixup */ for (j = v6start; j <= v6end; j++) s[j]->s.jt = s[v6advance]; } else #endif { /* nop */ s[i] = new_stmt(BPF_ALU | BPF_ADD | BPF_K); s[i]->s.k = 0; s[fix2]->s.jf = s[i]; i++; } /* ahcheck: */ ahcheck = i; /* if (A == IPPROTO_AH) then fall through; else goto end; */ s[i] = new_stmt(BPF_JMP | BPF_JEQ | BPF_K); s[i]->s.jt = NULL; /*later */ s[i]->s.jf = NULL; /*later */ s[i]->s.k = IPPROTO_AH; if (fix3) s[fix3]->s.jf = s[ahcheck]; fix4 = i; i++; /* * in short, * A = P[X]; * X = X + (P[X + 1] + 2) * 4; */ /* A = X */ s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC | BPF_TXA); i++; /* A = P[X + packet head]; */ s[i] = new_stmt(BPF_LD | BPF_IND | BPF_B); s[i]->s.k = off_macpl + off_nl; i++; /* MEM[reg2] = A */ s[i] = new_stmt(BPF_ST); s[i]->s.k = reg2; i++; /* A = X */ s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC | BPF_TXA); i++; /* A += 1 */ s[i] = new_stmt(BPF_ALU | BPF_ADD | BPF_K); s[i]->s.k = 1; i++; /* X = A */ s[i] = new_stmt(BPF_MISC | BPF_TAX); i++; /* A = P[X + packet head] */ s[i] = new_stmt(BPF_LD | BPF_IND | BPF_B); s[i]->s.k = off_macpl + off_nl; i++; /* A += 2 */ s[i] = new_stmt(BPF_ALU | BPF_ADD | BPF_K); s[i]->s.k = 2; i++; /* A *= 4 */ s[i] = new_stmt(BPF_ALU | BPF_MUL | BPF_K); s[i]->s.k = 4; i++; /* X = A; */ s[i] = new_stmt(BPF_MISC | BPF_TAX); i++; /* A = MEM[reg2] */ s[i] = new_stmt(BPF_LD | BPF_MEM); s[i]->s.k = reg2; i++; /* goto again; (must use BPF_JA for backward jump) */ s[i] = new_stmt(BPF_JMP | BPF_JA); s[i]->s.k = again - i - 1; i++; /* end: nop */ end = i; s[i] = new_stmt(BPF_ALU | BPF_ADD | BPF_K); s[i]->s.k = 0; s[fix2]->s.jt = s[end]; s[fix4]->s.jf = s[end]; s[fix5]->s.jt = s[end]; i++; /* * make slist chain */ max = i; for (i = 0; i < max - 1; i++) s[i]->next = s[i + 1]; s[max - 1]->next = NULL; /* * emit final check */ b = new_block(JMP(BPF_JEQ)); b->stmts = s[1]; /*remember, s[0] is dummy */ b->s.k = v; free_reg(reg2); gen_and(b0, b); return b; #endif } static struct block *gen_check_802_11_data_frame() { struct slist *s; struct block *b0, *b1; /* * A data frame has the 0x08 bit (b3) in the frame control field set * and the 0x04 bit (b2) clear. */ s = gen_load_a(OR_LINK, 0, BPF_B); b0 = new_block(JMP(BPF_JSET)); b0->s.k = 0x08; b0->stmts = s; s = gen_load_a(OR_LINK, 0, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x04; b1->stmts = s; gen_not(b1); gen_and(b1, b0); return b0; } /* * Generate code that checks whether the packet is a packet for protocol * and whether the type field in that protocol's header has * the value , e.g. if is Q_IP, it checks whether it's an * IP packet and checks the protocol number in the IP header against . * * If is Q_DEFAULT, i.e. just "proto" was specified, it checks * against Q_IP and Q_IPV6. */ static struct block *gen_proto(v, proto, dir) int v; int proto; int dir; { struct block *b0, *b1; if (dir != Q_DEFAULT) bpf_error("direction applied to 'proto'"); switch (proto) { case Q_DEFAULT: #ifdef INET6 b0 = gen_proto(v, Q_IP, dir); b1 = gen_proto(v, Q_IPV6, dir); gen_or(b0, b1); return b1; #else /*FALLTHROUGH*/ #endif case Q_IP: /* * For FDDI, RFC 1188 says that SNAP encapsulation is used, * not LLC encapsulation with LLCSAP_IP. * * For IEEE 802 networks - which includes 802.5 token ring * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042 * says that SNAP encapsulation is used, not LLC encapsulation * with LLCSAP_IP. * * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and * RFC 2225 say that SNAP encapsulation is used, not LLC * encapsulation with LLCSAP_IP. * * So we always check for ETHERTYPE_IP. */ b0 = gen_linktype(ETHERTYPE_IP); #ifndef CHASE_CHAIN b1 = gen_cmp(OR_NET, 9, BPF_B, (bpf_int32) v); #else b1 = gen_protochain(v, Q_IP); #endif gen_and(b0, b1); return b1; case Q_ISO: switch (linktype) { case DLT_FRELAY: /* * Frame Relay packets typically have an OSI * NLPID at the beginning; "gen_linktype(LLCSAP_ISONS)" * generates code to check for all the OSI * NLPIDs, so calling it and then adding a check * for the particular NLPID for which we're * looking is bogus, as we can just check for * the NLPID. * * What we check for is the NLPID and a frame * control field value of UI, i.e. 0x03 followed * by the NLPID. * * XXX - assumes a 2-byte Frame Relay header with * DLCI and flags. What if the address is longer? * * XXX - what about SNAP-encapsulated frames? */ return gen_cmp(OR_LINK, 2, BPF_H, (0x03 << 8) | v); /*NOTREACHED*/ break; case DLT_C_HDLC: /* * Cisco uses an Ethertype lookalike - for OSI, * it's 0xfefe. */ b0 = gen_linktype(LLCSAP_ISONS << 8 | LLCSAP_ISONS); /* OSI in C-HDLC is stuffed with a fudge byte */ b1 = gen_cmp(OR_NET_NOSNAP, 1, BPF_B, (long) v); gen_and(b0, b1); return b1; default: b0 = gen_linktype(LLCSAP_ISONS); b1 = gen_cmp(OR_NET_NOSNAP, 0, BPF_B, (long) v); gen_and(b0, b1); return b1; } case Q_ISIS: b0 = gen_proto(ISO10589_ISIS, Q_ISO, Q_DEFAULT); /* * 4 is the offset of the PDU type relative to the IS-IS * header. */ b1 = gen_cmp(OR_NET_NOSNAP, 4, BPF_B, (long) v); gen_and(b0, b1); return b1; case Q_ARP: bpf_error("arp does not encapsulate another protocol"); /* NOTREACHED */ case Q_RARP: bpf_error("rarp does not encapsulate another protocol"); /* NOTREACHED */ case Q_ATALK: bpf_error("atalk encapsulation is not specifiable"); /* NOTREACHED */ case Q_DECNET: bpf_error("decnet encapsulation is not specifiable"); /* NOTREACHED */ case Q_SCA: bpf_error("sca does not encapsulate another protocol"); /* NOTREACHED */ case Q_LAT: bpf_error("lat does not encapsulate another protocol"); /* NOTREACHED */ case Q_MOPRC: bpf_error("moprc does not encapsulate another protocol"); /* NOTREACHED */ case Q_MOPDL: bpf_error("mopdl does not encapsulate another protocol"); /* NOTREACHED */ case Q_LINK: return gen_linktype(v); case Q_UDP: bpf_error("'udp proto' is bogus"); /* NOTREACHED */ case Q_TCP: bpf_error("'tcp proto' is bogus"); /* NOTREACHED */ case Q_SCTP: bpf_error("'sctp proto' is bogus"); /* NOTREACHED */ case Q_ICMP: bpf_error("'icmp proto' is bogus"); /* NOTREACHED */ case Q_IGMP: bpf_error("'igmp proto' is bogus"); /* NOTREACHED */ case Q_IGRP: bpf_error("'igrp proto' is bogus"); /* NOTREACHED */ case Q_PIM: bpf_error("'pim proto' is bogus"); /* NOTREACHED */ case Q_VRRP: bpf_error("'vrrp proto' is bogus"); /* NOTREACHED */ #ifdef INET6 case Q_IPV6: b0 = gen_linktype(ETHERTYPE_IPV6); #ifndef CHASE_CHAIN b1 = gen_cmp(OR_NET, 6, BPF_B, (bpf_int32) v); #else b1 = gen_protochain(v, Q_IPV6); #endif gen_and(b0, b1); return b1; case Q_ICMPV6: bpf_error("'icmp6 proto' is bogus"); #endif /* INET6 */ case Q_AH: bpf_error("'ah proto' is bogus"); case Q_ESP: bpf_error("'ah proto' is bogus"); case Q_STP: bpf_error("'stp proto' is bogus"); case Q_IPX: bpf_error("'ipx proto' is bogus"); case Q_NETBEUI: bpf_error("'netbeui proto' is bogus"); case Q_RADIO: bpf_error("'radio proto' is bogus"); default: abort(); /* NOTREACHED */ } /* NOTREACHED */ } struct block *gen_scode(name, q) register const char *name; struct qual q; { int proto = q.proto; int dir = q.dir; int tproto; u_char *eaddr; bpf_u_int32 mask, addr; #ifndef INET6 bpf_u_int32 **alist; #else int tproto6; struct sockaddr_in *sin4; struct sockaddr_in6 *sin6; struct addrinfo *res, *res0; struct in6_addr mask128; #endif /*INET6 */ struct block *b, *tmp; int port, real_proto; int port1, port2; switch (q.addr) { case Q_NET: addr = pcap_nametonetaddr(name); if (addr == 0) bpf_error("unknown network '%s'", name); /* Left justify network addr and calculate its network mask */ mask = 0xffffffff; while (addr && (addr & 0xff000000) == 0) { addr <<= 8; mask <<= 8; } return gen_host(addr, mask, proto, dir, q.addr); case Q_DEFAULT: case Q_HOST: if (proto == Q_LINK) { switch (linktype) { case DLT_EN10MB: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error("unknown ether host '%s'", name); b = gen_ehostop(eaddr, dir); free(eaddr); return b; case DLT_FDDI: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error("unknown FDDI host '%s'", name); b = gen_fhostop(eaddr, dir); free(eaddr); return b; case DLT_IEEE802: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error("unknown token ring host '%s'", name); b = gen_thostop(eaddr, dir); free(eaddr); return b; case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error("unknown 802.11 host '%s'", name); b = gen_wlanhostop(eaddr, dir); free(eaddr); return b; case DLT_IP_OVER_FC: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error("unknown Fibre Channel host '%s'", name); b = gen_ipfchostop(eaddr, dir); free(eaddr); return b; case DLT_SUNATM: if (!is_lane) break; /* * Check that the packet doesn't begin * with an LE Control marker. (We've * already generated a test for LANE.) */ tmp = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00); gen_not(tmp); eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error("unknown ether host '%s'", name); b = gen_ehostop(eaddr, dir); gen_and(tmp, b); free(eaddr); return b; } bpf_error ("only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name"); } else if (proto == Q_DECNET) { unsigned short dn_addr = __pcap_nametodnaddr(name); /* * I don't think DECNET hosts can be multihomed, so * there is no need to build up a list of addresses */ return (gen_host(dn_addr, 0, proto, dir, q.addr)); } else { #ifndef INET6 alist = pcap_nametoaddr(name); if (alist == NULL || *alist == NULL) bpf_error("unknown host '%s'", name); tproto = proto; if (off_linktype == (u_int) - 1 && tproto == Q_DEFAULT) tproto = Q_IP; b = gen_host(**alist++, 0xffffffff, tproto, dir, q.addr); while (*alist) { tmp = gen_host(**alist++, 0xffffffff, tproto, dir, q.addr); gen_or(b, tmp); b = tmp; } return b; #else memset(&mask128, 0xff, sizeof(mask128)); res0 = res = pcap_nametoaddrinfo(name); if (res == NULL) bpf_error("unknown host '%s'", name); ai = res; b = tmp = NULL; tproto = tproto6 = proto; if (off_linktype == -1 && tproto == Q_DEFAULT) { tproto = Q_IP; tproto6 = Q_IPV6; } for (res = res0; res; res = res->ai_next) { switch (res->ai_family) { case AF_INET: if (tproto == Q_IPV6) continue; sin4 = (struct sockaddr_in *) res->ai_addr; tmp = gen_host(ntohl(sin4->sin_addr.s_addr), 0xffffffff, tproto, dir, q.addr); break; case AF_INET6: if (tproto6 == Q_IP) continue; sin6 = (struct sockaddr_in6 *) res->ai_addr; tmp = gen_host6(&sin6->sin6_addr, &mask128, tproto6, dir, q.addr); break; default: continue; } if (b) gen_or(b, tmp); b = tmp; } ai = NULL; freeaddrinfo(res0); if (b == NULL) { bpf_error("unknown host '%s'%s", name, (proto == Q_DEFAULT) ? "" : " for specified address family"); } return b; #endif /*INET6 */ } case Q_PORT: if (proto != Q_DEFAULT && proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP) bpf_error("illegal qualifier of 'port'"); if (pcap_nametoport(name, &port, &real_proto) == 0) bpf_error("unknown port '%s'", name); if (proto == Q_UDP) { if (real_proto == IPPROTO_TCP) bpf_error("port '%s' is tcp", name); else if (real_proto == IPPROTO_SCTP) bpf_error("port '%s' is sctp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_UDP; } if (proto == Q_TCP) { if (real_proto == IPPROTO_UDP) bpf_error("port '%s' is udp", name); else if (real_proto == IPPROTO_SCTP) bpf_error("port '%s' is sctp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_TCP; } if (proto == Q_SCTP) { if (real_proto == IPPROTO_UDP) bpf_error("port '%s' is udp", name); else if (real_proto == IPPROTO_TCP) bpf_error("port '%s' is tcp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_SCTP; } #ifndef INET6 return gen_port(port, real_proto, dir); #else b = gen_port(port, real_proto, dir); gen_or(gen_port6(port, real_proto, dir), b); return b; #endif /* INET6 */ case Q_PORTRANGE: if (proto != Q_DEFAULT && proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP) bpf_error("illegal qualifier of 'portrange'"); if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0) bpf_error("unknown port in range '%s'", name); if (proto == Q_UDP) { if (real_proto == IPPROTO_TCP) bpf_error("port in range '%s' is tcp", name); else if (real_proto == IPPROTO_SCTP) bpf_error("port in range '%s' is sctp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_UDP; } if (proto == Q_TCP) { if (real_proto == IPPROTO_UDP) bpf_error("port in range '%s' is udp", name); else if (real_proto == IPPROTO_SCTP) bpf_error("port in range '%s' is sctp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_TCP; } if (proto == Q_SCTP) { if (real_proto == IPPROTO_UDP) bpf_error("port in range '%s' is udp", name); else if (real_proto == IPPROTO_TCP) bpf_error("port in range '%s' is tcp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_SCTP; } #ifndef INET6 return gen_portrange(port1, port2, real_proto, dir); #else b = gen_portrange(port1, port2, real_proto, dir); gen_or(gen_portrange6(port1, port2, real_proto, dir), b); return b; #endif /* INET6 */ case Q_GATEWAY: #ifndef INET6 eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error("unknown ether host: %s", name); alist = pcap_nametoaddr(name); if (alist == NULL || *alist == NULL) bpf_error("unknown host '%s'", name); b = gen_gateway(eaddr, alist, proto, dir); free(eaddr); return b; #else bpf_error("'gateway' not supported in this configuration"); #endif /*INET6 */ case Q_PROTO: real_proto = lookup_proto(name, proto); if (real_proto >= 0) return gen_proto(real_proto, proto, dir); else bpf_error("unknown protocol: %s", name); case Q_PROTOCHAIN: real_proto = lookup_proto(name, proto); if (real_proto >= 0) return gen_protochain(real_proto, proto, dir); else bpf_error("unknown protocol: %s", name); case Q_UNDEF: syntax(); /* NOTREACHED */ } abort(); /* NOTREACHED */ } struct block *gen_mcode(s1, s2, masklen, q) register const char *s1, *s2; register int masklen; struct qual q; { register int nlen, mlen; bpf_u_int32 n, m; nlen = __pcap_atoin(s1, &n); /* Promote short ipaddr */ n <<= 32 - nlen; if (s2 != NULL) { mlen = __pcap_atoin(s2, &m); /* Promote short ipaddr */ m <<= 32 - mlen; if ((n & ~m) != 0) bpf_error("non-network bits set in \"%s mask %s\"", s1, s2); } else { /* Convert mask len to mask */ if (masklen > 32) bpf_error("mask length must be <= 32"); if (masklen == 0) { /* * X << 32 is not guaranteed by C to be 0; it's * undefined. */ m = 0; } else m = 0xffffffff << (32 - masklen); if ((n & ~m) != 0) bpf_error("non-network bits set in \"%s/%d\"", s1, masklen); } switch (q.addr) { case Q_NET: return gen_host(n, m, q.proto, q.dir, q.addr); default: bpf_error("Mask syntax for networks only"); /* NOTREACHED */ } /* NOTREACHED */ return NULL; } struct block *gen_ncode(s, v, q) register const char *s; bpf_u_int32 v; struct qual q; { bpf_u_int32 mask; int proto = q.proto; int dir = q.dir; register int vlen; if (s == NULL) vlen = 32; else if (q.proto == Q_DECNET) vlen = __pcap_atodn(s, &v); else vlen = __pcap_atoin(s, &v); switch (q.addr) { case Q_DEFAULT: case Q_HOST: case Q_NET: if (proto == Q_DECNET) return gen_host(v, 0, proto, dir, q.addr); else if (proto == Q_LINK) { bpf_error("illegal link layer address"); } else { mask = 0xffffffff; if (s == NULL && q.addr == Q_NET) { /* Promote short net number */ while (v && (v & 0xff000000) == 0) { v <<= 8; mask <<= 8; } } else { /* Promote short ipaddr */ v <<= 32 - vlen; mask <<= 32 - vlen; } return gen_host(v, mask, proto, dir, q.addr); } case Q_PORT: if (proto == Q_UDP) proto = IPPROTO_UDP; else if (proto == Q_TCP) proto = IPPROTO_TCP; else if (proto == Q_SCTP) proto = IPPROTO_SCTP; else if (proto == Q_DEFAULT) proto = PROTO_UNDEF; else bpf_error("illegal qualifier of 'port'"); #ifndef INET6 return gen_port((int) v, proto, dir); #else { struct block *b; b = gen_port((int) v, proto, dir); gen_or(gen_port6((int) v, proto, dir), b); return b; } #endif /* INET6 */ case Q_PORTRANGE: if (proto == Q_UDP) proto = IPPROTO_UDP; else if (proto == Q_TCP) proto = IPPROTO_TCP; else if (proto == Q_SCTP) proto = IPPROTO_SCTP; else if (proto == Q_DEFAULT) proto = PROTO_UNDEF; else bpf_error("illegal qualifier of 'portrange'"); #ifndef INET6 return gen_portrange((int) v, (int) v, proto, dir); #else { struct block *b; b = gen_portrange((int) v, (int) v, proto, dir); gen_or(gen_portrange6((int) v, (int) v, proto, dir), b); return b; } #endif /* INET6 */ case Q_GATEWAY: bpf_error("'gateway' requires a name"); /* NOTREACHED */ case Q_PROTO: return gen_proto((int) v, proto, dir); case Q_PROTOCHAIN: return gen_protochain((int) v, proto, dir); case Q_UNDEF: syntax(); /* NOTREACHED */ default: abort(); /* NOTREACHED */ } /* NOTREACHED */ } #ifdef INET6 struct block *gen_mcode6(s1, s2, masklen, q) register const char *s1, *s2; register int masklen; struct qual q; { struct addrinfo *res; struct in6_addr *addr; struct in6_addr mask; struct block *b; u_int32_t *a, *m; if (s2) bpf_error("no mask %s supported", s2); res = pcap_nametoaddrinfo(s1); if (!res) bpf_error("invalid ip6 address %s", s1); ai = res; if (res->ai_next) bpf_error("%s resolved to multiple address", s1); addr = &((struct sockaddr_in6 *) res->ai_addr)->sin6_addr; if (sizeof(mask) * 8 < masklen) bpf_error("mask length must be <= %u", (unsigned int) (sizeof(mask) * 8)); memset(&mask, 0, sizeof(mask)); memset(&mask, 0xff, masklen / 8); if (masklen % 8) { mask.s6_addr[masklen / 8] = (0xff << (8 - masklen % 8)) & 0xff; } a = (u_int32_t *) addr; m = (u_int32_t *) & mask; if ((a[0] & ~m[0]) || (a[1] & ~m[1]) || (a[2] & ~m[2]) || (a[3] & ~m[3])) { bpf_error("non-network bits set in \"%s/%d\"", s1, masklen); } switch (q.addr) { case Q_DEFAULT: case Q_HOST: if (masklen != 128) bpf_error("Mask syntax for networks only"); /* FALLTHROUGH */ case Q_NET: b = gen_host6(addr, &mask, q.proto, q.dir, q.addr); ai = NULL; freeaddrinfo(res); return b; default: bpf_error("invalid qualifier against IPv6 address"); /* NOTREACHED */ } return NULL; } #endif /*INET6 */ struct block *gen_ecode(eaddr, q) register const u_char *eaddr; struct qual q; { struct block *b, *tmp; if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) { switch (linktype) { case DLT_EN10MB: return gen_ehostop(eaddr, (int) q.dir); case DLT_FDDI: return gen_fhostop(eaddr, (int) q.dir); case DLT_IEEE802: return gen_thostop(eaddr, (int) q.dir); case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: return gen_wlanhostop(eaddr, (int) q.dir); case DLT_SUNATM: if (is_lane) { /* * Check that the packet doesn't begin with an * LE Control marker. (We've already generated * a test for LANE.) */ tmp = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00); gen_not(tmp); /* * Now check the MAC address. */ b = gen_ehostop(eaddr, (int) q.dir); gen_and(tmp, b); return b; } break; case DLT_IP_OVER_FC: return gen_ipfchostop(eaddr, (int) q.dir); default: bpf_error ("ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel"); break; } } bpf_error("ethernet address used in non-ether expression"); /* NOTREACHED */ return NULL; } void sappend(s0, s1) struct slist *s0, *s1; { /* * This is definitely not the best way to do this, but the * lists will rarely get long. */ while (s0->next) s0 = s0->next; s0->next = s1; } static struct slist *xfer_to_x(a) struct arth *a; { struct slist *s; s = new_stmt(BPF_LDX | BPF_MEM); s->s.k = a->regno; return s; } static struct slist *xfer_to_a(a) struct arth *a; { struct slist *s; s = new_stmt(BPF_LD | BPF_MEM); s->s.k = a->regno; return s; } /* * Modify "index" to use the value stored into its register as an * offset relative to the beginning of the header for the protocol * "proto", and allocate a register and put an item "size" bytes long * (1, 2, or 4) at that offset into that register, making it the register * for "index". */ struct arth *gen_load(proto, inst, size) int proto; struct arth *inst; int size; { struct slist *s, *tmp; struct block *b; int regno = alloc_reg(); free_reg(inst->regno); switch (size) { default: bpf_error("data size must be 1, 2, or 4"); case 1: size = BPF_B; break; case 2: size = BPF_H; break; case 4: size = BPF_W; break; } switch (proto) { default: bpf_error("unsupported index operation"); case Q_RADIO: /* * The offset is relative to the beginning of the packet * data, if we have a radio header. (If we don't, this * is an error.) */ if (linktype != DLT_IEEE802_11_RADIO_AVS && linktype != DLT_IEEE802_11_RADIO && linktype != DLT_PRISM_HEADER) bpf_error("radio information not present in capture"); /* * Load into the X register the offset computed into the * register specifed by "index". */ s = xfer_to_x(inst); /* * Load the item at that offset. */ tmp = new_stmt(BPF_LD | BPF_IND | size); sappend(s, tmp); sappend(inst->s, s); break; case Q_LINK: /* * The offset is relative to the beginning of * the link-layer header. * * XXX - what about ATM LANE? Should the index be * relative to the beginning of the AAL5 frame, so * that 0 refers to the beginning of the LE Control * field, or relative to the beginning of the LAN * frame, so that 0 refers, for Ethernet LANE, to * the beginning of the destination address? */ s = gen_llprefixlen(); /* * If "s" is non-null, it has code to arrange that the * X register contains the length of the prefix preceding * the link-layer header. Add to it the offset computed * into the register specified by "index", and move that * into the X register. Otherwise, just load into the X * register the offset computed into the register specifed * by "index". */ if (s != NULL) { sappend(s, xfer_to_a(inst)); sappend(s, new_stmt(BPF_ALU | BPF_ADD | BPF_X)); sappend(s, new_stmt(BPF_MISC | BPF_TAX)); } else s = xfer_to_x(inst); /* * Load the item at the sum of the offset we've put in the * X register and the offset of the start of the link * layer header (which is 0 if the radio header is * variable-length; that header length is what we put * into the X register and then added to the index). */ tmp = new_stmt(BPF_LD | BPF_IND | size); tmp->s.k = off_ll; sappend(s, tmp); sappend(inst->s, s); break; case Q_IP: case Q_ARP: case Q_RARP: case Q_ATALK: case Q_DECNET: case Q_SCA: case Q_LAT: case Q_MOPRC: case Q_MOPDL: #ifdef INET6 case Q_IPV6: #endif /* * The offset is relative to the beginning of * the network-layer header. * XXX - are there any cases where we want * off_nl_nosnap? */ s = gen_off_macpl(); /* * If "s" is non-null, it has code to arrange that the * X register contains the offset of the MAC-layer * payload. Add to it the offset computed into the * register specified by "index", and move that into * the X register. Otherwise, just load into the X * register the offset computed into the register specifed * by "index". */ if (s != NULL) { sappend(s, xfer_to_a(inst)); sappend(s, new_stmt(BPF_ALU | BPF_ADD | BPF_X)); sappend(s, new_stmt(BPF_MISC | BPF_TAX)); } else s = xfer_to_x(inst); /* * Load the item at the sum of the offset we've put in the * X register, the offset of the start of the network * layer header from the beginning of the MAC-layer * payload, and the purported offset of the start of the * MAC-layer payload (which might be 0 if there's a * variable-length prefix before the link-layer header * or the link-layer header itself is variable-length; * the variable-length offset of the start of the * MAC-layer payload is what we put into the X register * and then added to the index). */ tmp = new_stmt(BPF_LD | BPF_IND | size); tmp->s.k = off_macpl + off_nl; sappend(s, tmp); sappend(inst->s, s); /* * Do the computation only if the packet contains * the protocol in question. */ b = gen_proto_abbrev(proto); if (inst->b) gen_and(inst->b, b); inst->b = b; break; case Q_SCTP: case Q_TCP: case Q_UDP: case Q_ICMP: case Q_IGMP: case Q_IGRP: case Q_PIM: case Q_VRRP: /* * The offset is relative to the beginning of * the transport-layer header. * * Load the X register with the length of the IPv4 header * (plus the offset of the link-layer header, if it's * a variable-length header), in bytes. * * XXX - are there any cases where we want * off_nl_nosnap? * XXX - we should, if we're built with * IPv6 support, generate code to load either * IPv4, IPv6, or both, as appropriate. */ s = gen_loadx_iphdrlen(); /* * The X register now contains the sum of the length * of any variable-length header preceding the link-layer * header, any variable-length link-layer header, and the * length of the network-layer header. * * Load into the A register the offset relative to * the beginning of the transport layer header, * add the X register to that, move that to the * X register, and load with an offset from the * X register equal to the offset of the network * layer header relative to the beginning of * the MAC-layer payload plus the fixed-length * portion of the offset of the MAC-layer payload * from the beginning of the raw packet data. */ sappend(s, xfer_to_a(inst)); sappend(s, new_stmt(BPF_ALU | BPF_ADD | BPF_X)); sappend(s, new_stmt(BPF_MISC | BPF_TAX)); sappend(s, tmp = new_stmt(BPF_LD | BPF_IND | size)); tmp->s.k = off_macpl + off_nl; sappend(inst->s, s); /* * Do the computation only if the packet contains * the protocol in question - which is true only * if this is an IP datagram and is the first or * only fragment of that datagram. */ gen_and(gen_proto_abbrev(proto), b = gen_ipfrag()); if (inst->b) gen_and(inst->b, b); #ifdef INET6 gen_and(gen_proto_abbrev(Q_IP), b); #endif inst->b = b; break; #ifdef INET6 case Q_ICMPV6: bpf_error("IPv6 upper-layer protocol is not supported by proto[x]"); /*NOTREACHED*/ #endif } inst->regno = regno; s = new_stmt(BPF_ST); s->s.k = regno; sappend(inst->s, s); return inst; } struct block *gen_relation(code, a0, a1, reversed) int code; struct arth *a0, *a1; int reversed; { struct slist *s0, *s1, *s2; struct block *b, *tmp; s0 = xfer_to_x(a1); s1 = xfer_to_a(a0); if (code == BPF_JEQ) { s2 = new_stmt(BPF_ALU | BPF_SUB | BPF_X); b = new_block(JMP(code)); sappend(s1, s2); } else b = new_block(BPF_JMP | code | BPF_X); if (reversed) gen_not(b); sappend(s0, s1); sappend(a1->s, s0); sappend(a0->s, a1->s); b->stmts = a0->s; free_reg(a0->regno); free_reg(a1->regno); /* 'and' together protocol checks */ if (a0->b) { if (a1->b) { gen_and(a0->b, tmp = a1->b); } else tmp = a0->b; } else tmp = a1->b; if (tmp) gen_and(tmp, b); return b; } struct arth *gen_loadlen() { int regno = alloc_reg(); struct arth *a = (struct arth *) newchunk(sizeof(*a)); struct slist *s; s = new_stmt(BPF_LD | BPF_LEN); s->next = new_stmt(BPF_ST); s->next->s.k = regno; a->s = s; a->regno = regno; return a; } struct arth *gen_loadi(val) int val; { struct arth *a; struct slist *s; int reg; a = (struct arth *) newchunk(sizeof(*a)); reg = alloc_reg(); s = new_stmt(BPF_LD | BPF_IMM); s->s.k = val; s->next = new_stmt(BPF_ST); s->next->s.k = reg; a->s = s; a->regno = reg; return a; } struct arth *gen_neg(a) struct arth *a; { struct slist *s; s = xfer_to_a(a); sappend(a->s, s); s = new_stmt(BPF_ALU | BPF_NEG); s->s.k = 0; sappend(a->s, s); s = new_stmt(BPF_ST); s->s.k = a->regno; sappend(a->s, s); return a; } struct arth *gen_arth(code, a0, a1) int code; struct arth *a0, *a1; { struct slist *s0, *s1, *s2; s0 = xfer_to_x(a1); s1 = xfer_to_a(a0); s2 = new_stmt(BPF_ALU | BPF_X | code); sappend(s1, s2); sappend(s0, s1); sappend(a1->s, s0); sappend(a0->s, a1->s); free_reg(a0->regno); free_reg(a1->regno); s0 = new_stmt(BPF_ST); a0->regno = s0->s.k = alloc_reg(); sappend(a0->s, s0); return a0; } /* * Here we handle simple allocation of the scratch registers. * If too many registers are alloc'd, the allocator punts. */ static __thread int regused[BPF_MEMWORDS]; static __thread int curreg; /* * Initialize the table of used registers and the current register. */ static void init_regs() { curreg = 0; memset(regused, 0, sizeof regused); } /* * Return the next free register. */ static int alloc_reg() { int n = BPF_MEMWORDS; while (--n >= 0) { if (regused[curreg]) curreg = (curreg + 1) % BPF_MEMWORDS; else { regused[curreg] = 1; return curreg; } } bpf_error("too many registers needed to evaluate expression"); /* NOTREACHED */ return 0; } /* * Return a register to the table so it can * be used later. */ static void free_reg(n) int n; { regused[n] = 0; } static struct block *gen_len(jmp, n) int jmp, n; { struct slist *s; struct block *b; s = new_stmt(BPF_LD | BPF_LEN); b = new_block(JMP(jmp)); b->stmts = s; b->s.k = n; return b; } struct block *gen_greater(n) int n; { return gen_len(BPF_JGE, n); } /* * Actually, this is less than or equal. */ struct block *gen_less(n) int n; { struct block *b; b = gen_len(BPF_JGT, n); gen_not(b); return b; } /* * This is for "byte {idx} {op} {val}"; "idx" is treated as relative to * the beginning of the link-layer header. * XXX - that means you can't test values in the radiotap header, but * as that header is difficult if not impossible to parse generally * without a loop, that might not be a severe problem. A new keyword * "radio" could be added for that, although what you'd really want * would be a way of testing particular radio header values, which * would generate code appropriate to the radio header in question. */ struct block *gen_byteop(op, idx, val) int op, idx, val; { struct block *b; struct slist *s; switch (op) { default: abort(); case '=': return gen_cmp(OR_LINK, (u_int) idx, BPF_B, (bpf_int32) val); case '<': b = gen_cmp_lt(OR_LINK, (u_int) idx, BPF_B, (bpf_int32) val); return b; case '>': b = gen_cmp_gt(OR_LINK, (u_int) idx, BPF_B, (bpf_int32) val); return b; case '|': s = new_stmt(BPF_ALU | BPF_OR | BPF_K); break; case '&': s = new_stmt(BPF_ALU | BPF_AND | BPF_K); break; } s->s.k = val; b = new_block(JMP(BPF_JEQ)); b->stmts = s; gen_not(b); return b; } static __thread u_char abroadcast[] = { 0x0 }; struct block *gen_broadcast(proto) int proto; { bpf_u_int32 hostmask; struct block *b0, *b1, *b2; static u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; switch (proto) { case Q_DEFAULT: case Q_LINK: switch (linktype) { case DLT_ARCNET: case DLT_ARCNET_LINUX: return gen_ahostop(abroadcast, Q_DST); case DLT_EN10MB: return gen_ehostop(ebroadcast, Q_DST); case DLT_FDDI: return gen_fhostop(ebroadcast, Q_DST); case DLT_IEEE802: return gen_thostop(ebroadcast, Q_DST); case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: return gen_wlanhostop(ebroadcast, Q_DST); case DLT_IP_OVER_FC: return gen_ipfchostop(ebroadcast, Q_DST); case DLT_SUNATM: if (is_lane) { /* * Check that the packet doesn't begin with an * LE Control marker. (We've already generated * a test for LANE.) */ b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00); gen_not(b1); /* * Now check the MAC address. */ b0 = gen_ehostop(ebroadcast, Q_DST); gen_and(b1, b0); return b0; } break; default: bpf_error("not a broadcast link"); } break; case Q_IP: /* * We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff) * as an indication that we don't know the netmask, and fail * in that case. */ if (netmask == PCAP_NETMASK_UNKNOWN) bpf_error("netmask not known, so 'ip broadcast' not supported"); b0 = gen_linktype(ETHERTYPE_IP); hostmask = ~netmask; b1 = gen_mcmp(OR_NET, 16, BPF_W, (bpf_int32) 0, hostmask); b2 = gen_mcmp(OR_NET, 16, BPF_W, (bpf_int32) (~0 & hostmask), hostmask); gen_or(b1, b2); gen_and(b0, b2); return b2; } bpf_error("only link-layer/IP broadcast filters supported"); /* NOTREACHED */ return NULL; } /* * Generate code to test the low-order bit of a MAC address (that's * the bottom bit of the *first* byte). */ static struct block *gen_mac_multicast(offset) int offset; { register struct block *b0; register struct slist *s; /* link[offset] & 1 != 0 */ s = gen_load_a(OR_LINK, offset, BPF_B); b0 = new_block(JMP(BPF_JSET)); b0->s.k = 1; b0->stmts = s; return b0; } struct block *gen_multicast(proto) int proto; { register struct block *b0, *b1, *b2; register struct slist *s; switch (proto) { case Q_DEFAULT: case Q_LINK: switch (linktype) { case DLT_ARCNET: case DLT_ARCNET_LINUX: /* all ARCnet multicasts use the same address */ return gen_ahostop(abroadcast, Q_DST); case DLT_EN10MB: /* ether[0] & 1 != 0 */ return gen_mac_multicast(0); case DLT_FDDI: /* * XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX * * XXX - was that referring to bit-order issues? */ /* fddi[1] & 1 != 0 */ return gen_mac_multicast(1); case DLT_IEEE802: /* tr[2] & 1 != 0 */ return gen_mac_multicast(2); case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: case DLT_PPI: /* * Oh, yuk. * * For control frames, there is no DA. * * For management frames, DA is at an * offset of 4 from the beginning of * the packet. * * For data frames, DA is at an offset * of 4 from the beginning of the packet * if To DS is clear and at an offset of * 16 from the beginning of the packet * if To DS is set. */ /* * Generate the tests to be done for data frames. * * First, check for To DS set, i.e. "link[1] & 0x01". */ s = gen_load_a(OR_LINK, 1, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x01; /* To DS */ b1->stmts = s; /* * If To DS is set, the DA is at 16. */ b0 = gen_mac_multicast(16); gen_and(b1, b0); /* * Now, check for To DS not set, i.e. check * "!(link[1] & 0x01)". */ s = gen_load_a(OR_LINK, 1, BPF_B); b2 = new_block(JMP(BPF_JSET)); b2->s.k = 0x01; /* To DS */ b2->stmts = s; gen_not(b2); /* * If To DS is not set, the DA is at 4. */ b1 = gen_mac_multicast(4); gen_and(b2, b1); /* * Now OR together the last two checks. That gives * the complete set of checks for data frames. */ gen_or(b1, b0); /* * Now check for a data frame. * I.e, check "link[0] & 0x08". */ s = gen_load_a(OR_LINK, 0, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x08; b1->stmts = s; /* * AND that with the checks done for data frames. */ gen_and(b1, b0); /* * If the high-order bit of the type value is 0, this * is a management frame. * I.e, check "!(link[0] & 0x08)". */ s = gen_load_a(OR_LINK, 0, BPF_B); b2 = new_block(JMP(BPF_JSET)); b2->s.k = 0x08; b2->stmts = s; gen_not(b2); /* * For management frames, the DA is at 4. */ b1 = gen_mac_multicast(4); gen_and(b2, b1); /* * OR that with the checks done for data frames. * That gives the checks done for management and * data frames. */ gen_or(b1, b0); /* * If the low-order bit of the type value is 1, * this is either a control frame or a frame * with a reserved type, and thus not a * frame with an SA. * * I.e., check "!(link[0] & 0x04)". */ s = gen_load_a(OR_LINK, 0, BPF_B); b1 = new_block(JMP(BPF_JSET)); b1->s.k = 0x04; b1->stmts = s; gen_not(b1); /* * AND that with the checks for data and management * frames. */ gen_and(b1, b0); return b0; case DLT_IP_OVER_FC: b0 = gen_mac_multicast(2); return b0; case DLT_SUNATM: if (is_lane) { /* * Check that the packet doesn't begin with an * LE Control marker. (We've already generated * a test for LANE.) */ b1 = gen_cmp(OR_LINK, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00); gen_not(b1); /* ether[off_mac] & 1 != 0 */ b0 = gen_mac_multicast(off_mac); gen_and(b1, b0); return b0; } break; default: break; } /* Link not known to support multicasts */ break; case Q_IP: b0 = gen_linktype(ETHERTYPE_IP); b1 = gen_cmp_ge(OR_NET, 16, BPF_B, (bpf_int32) 224); gen_and(b0, b1); return b1; #ifdef INET6 case Q_IPV6: b0 = gen_linktype(ETHERTYPE_IPV6); b1 = gen_cmp(OR_NET, 24, BPF_B, (bpf_int32) 255); gen_and(b0, b1); return b1; #endif /* INET6 */ } bpf_error ("link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel"); /* NOTREACHED */ return NULL; } /* * generate command for inbound/outbound. It's here so we can * make it link-type specific. 'dir' = 0 implies "inbound", * = 1 implies "outbound". */ struct block *gen_inbound(dir) int dir; { register struct block *b0; /* * Only some data link types support inbound/outbound qualifiers. */ switch (linktype) { case DLT_SLIP: b0 = gen_relation(BPF_JEQ, gen_load(Q_LINK, gen_loadi(0), 1), gen_loadi(0), dir); break; case DLT_IPNET: if (dir) { /* match outgoing packets */ b0 = gen_cmp(OR_LINK, 2, BPF_H, IPNET_OUTBOUND); } else { /* match incoming packets */ b0 = gen_cmp(OR_LINK, 2, BPF_H, IPNET_INBOUND); } break; case DLT_LINUX_SLL: if (dir) { /* * Match packets sent by this machine. */ b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_OUTGOING); } else { /* * Match packets sent to this machine. * (No broadcast or multicast packets, or * packets sent to some other machine and * received promiscuously.) * * XXX - packets sent to other machines probably * shouldn't be matched, but what about broadcast * or multicast packets we received? */ b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_HOST); } break; #ifdef HAVE_NET_PFVAR_H case DLT_PFLOG: b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, dir), BPF_B, (bpf_int32) ((dir == 0) ? PF_IN : PF_OUT)); break; #endif case DLT_PPP_PPPD: if (dir) { /* match outgoing packets */ b0 = gen_cmp(OR_LINK, 0, BPF_B, PPP_PPPD_OUT); } else { /* match incoming packets */ b0 = gen_cmp(OR_LINK, 0, BPF_B, PPP_PPPD_IN); } break; case DLT_JUNIPER_MFR: case DLT_JUNIPER_MLFR: case DLT_JUNIPER_MLPPP: case DLT_JUNIPER_ATM1: case DLT_JUNIPER_ATM2: case DLT_JUNIPER_PPPOE: case DLT_JUNIPER_PPPOE_ATM: case DLT_JUNIPER_GGSN: case DLT_JUNIPER_ES: case DLT_JUNIPER_MONITOR: case DLT_JUNIPER_SERVICES: case DLT_JUNIPER_ETHER: case DLT_JUNIPER_PPP: case DLT_JUNIPER_FRELAY: case DLT_JUNIPER_CHDLC: case DLT_JUNIPER_VP: case DLT_JUNIPER_ST: case DLT_JUNIPER_ISM: /* juniper flags (including direction) are stored * the byte after the 3-byte magic number */ if (dir) { /* match outgoing packets */ b0 = gen_mcmp(OR_LINK, 3, BPF_B, 0, 0x01); } else { /* match incoming packets */ b0 = gen_mcmp(OR_LINK, 3, BPF_B, 1, 0x01); } break; default: bpf_error("inbound/outbound not supported on linktype %d", linktype); b0 = NULL; /* NOTREACHED */ } return (b0); } #ifdef HAVE_NET_PFVAR_H /* PF firewall log matched interface */ struct block *gen_pf_ifname(const char *ifname) { struct block *b0; u_int len, off; if (linktype != DLT_PFLOG) { bpf_error("ifname supported only on PF linktype"); /* NOTREACHED */ } len = sizeof(((struct pfloghdr *) 0)->ifname); off = offsetof(struct pfloghdr, ifname); if (strlen(ifname) >= len) { bpf_error("ifname interface names can only be %d characters", len - 1); /* NOTREACHED */ } b0 = gen_bcmp(OR_LINK, off, strlen(ifname), (const u_char *) ifname); return (b0); } /* PF firewall log ruleset name */ struct block *gen_pf_ruleset(char *ruleset) { struct block *b0; if (linktype != DLT_PFLOG) { bpf_error("ruleset supported only on PF linktype"); /* NOTREACHED */ } if (strlen(ruleset) >= sizeof(((struct pfloghdr *) 0)->ruleset)) { bpf_error("ruleset names can only be %ld characters", (long) (sizeof(((struct pfloghdr *) 0)->ruleset) - 1)); /* NOTREACHED */ } b0 = gen_bcmp(OR_LINK, offsetof(struct pfloghdr, ruleset), strlen(ruleset), (const u_char *) ruleset); return (b0); } /* PF firewall log rule number */ struct block *gen_pf_rnr(int rnr) { struct block *b0; if (linktype != DLT_PFLOG) { bpf_error("rnr supported only on PF linktype"); /* NOTREACHED */ } b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, rulenr), BPF_W, (bpf_int32) rnr); return (b0); } /* PF firewall log sub-rule number */ struct block *gen_pf_srnr(int srnr) { struct block *b0; if (linktype != DLT_PFLOG) { bpf_error("srnr supported only on PF linktype"); /* NOTREACHED */ } b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, subrulenr), BPF_W, (bpf_int32) srnr); return (b0); } /* PF firewall log reason code */ struct block *gen_pf_reason(int reason) { struct block *b0; if (linktype != DLT_PFLOG) { bpf_error("reason supported only on PF linktype"); /* NOTREACHED */ } b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, reason), BPF_B, (bpf_int32) reason); return (b0); } /* PF firewall log action */ struct block *gen_pf_action(int action) { struct block *b0; if (linktype != DLT_PFLOG) { bpf_error("action supported only on PF linktype"); /* NOTREACHED */ } b0 = gen_cmp(OR_LINK, offsetof(struct pfloghdr, action), BPF_B, (bpf_int32) action); return (b0); } #else /* !HAVE_NET_PFVAR_H */ struct block *gen_pf_ifname(const char *ifname) { bpf_error("libpcap was compiled without pf support"); /* NOTREACHED */ return (NULL); } struct block *gen_pf_ruleset(char *ruleset) { bpf_error("libpcap was compiled on a machine without pf support"); /* NOTREACHED */ return (NULL); } struct block *gen_pf_rnr(int rnr) { bpf_error("libpcap was compiled on a machine without pf support"); /* NOTREACHED */ return (NULL); } struct block *gen_pf_srnr(int srnr) { bpf_error("libpcap was compiled on a machine without pf support"); /* NOTREACHED */ return (NULL); } struct block *gen_pf_reason(int reason) { bpf_error("libpcap was compiled on a machine without pf support"); /* NOTREACHED */ return (NULL); } struct block *gen_pf_action(int action) { bpf_error("libpcap was compiled on a machine without pf support"); /* NOTREACHED */ return (NULL); } #endif /* HAVE_NET_PFVAR_H */ /* IEEE 802.11 wireless header */ struct block *gen_p80211_type(int type, int mask) { struct block *b0; switch (linktype) { case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: b0 = gen_mcmp(OR_LINK, 0, BPF_B, (bpf_int32) type, (bpf_int32) mask); break; default: bpf_error("802.11 link-layer types supported only on 802.11"); /* NOTREACHED */ } return (b0); } struct block *gen_p80211_fcdir(int fcdir) { struct block *b0; switch (linktype) { case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_IEEE802_11_RADIO_AVS: case DLT_IEEE802_11_RADIO: break; default: bpf_error("frame direction supported only with 802.11 headers"); /* NOTREACHED */ } b0 = gen_mcmp(OR_LINK, 1, BPF_B, (bpf_int32) fcdir, (bpf_u_int32) IEEE80211_FC1_DIR_MASK); return (b0); } struct block *gen_acode(eaddr, q) register const u_char *eaddr; struct qual q; { switch (linktype) { case DLT_ARCNET: case DLT_ARCNET_LINUX: if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) return (gen_ahostop(eaddr, (int) q.dir)); else { bpf_error("ARCnet address used in non-arc expression"); /* NOTREACHED */ } break; default: bpf_error("aid supported only on ARCnet"); /* NOTREACHED */ } bpf_error("ARCnet address used in non-arc expression"); /* NOTREACHED */ return NULL; } static struct block *gen_ahostop(eaddr, dir) register const u_char *eaddr; register int dir; { register struct block *b0, *b1; switch (dir) { /* src comes first, different from Ethernet */ case Q_SRC: return gen_bcmp(OR_LINK, 0, 1, eaddr); case Q_DST: return gen_bcmp(OR_LINK, 1, 1, eaddr); case Q_AND: b0 = gen_ahostop(eaddr, Q_SRC); b1 = gen_ahostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_ahostop(eaddr, Q_SRC); b1 = gen_ahostop(eaddr, Q_DST); gen_or(b0, b1); return b1; } abort(); /* NOTREACHED */ } /* * support IEEE 802.1Q VLAN trunk over ethernet */ struct block *gen_vlan(vlan_num) int vlan_num; { struct block *b0, *b1; /* can't check for VLAN-encapsulated packets inside MPLS */ if (label_stack_depth > 0) bpf_error("no VLAN match after MPLS"); /* * Check for a VLAN packet, and then change the offsets to point * to the type and data fields within the VLAN packet. Just * increment the offsets, so that we can support a hierarchy, e.g. * "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within * VLAN 100. * * XXX - this is a bit of a kludge. If we were to split the * compiler into a parser that parses an expression and * generates an expression tree, and a code generator that * takes an expression tree (which could come from our * parser or from some other parser) and generates BPF code, * we could perhaps make the offsets parameters of routines * and, in the handler for an "AND" node, pass to subnodes * other than the VLAN node the adjusted offsets. * * This would mean that "vlan" would, instead of changing the * behavior of *all* tests after it, change only the behavior * of tests ANDed with it. That would change the documented * semantics of "vlan", which might break some expressions. * However, it would mean that "(vlan and ip) or ip" would check * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than * checking only for VLAN-encapsulated IP, so that could still * be considered worth doing; it wouldn't break expressions * that are of the form "vlan and ..." or "vlan N and ...", * which I suspect are the most common expressions involving * "vlan". "vlan or ..." doesn't necessarily do what the user * would really want, now, as all the "or ..." tests would * be done assuming a VLAN, even though the "or" could be viewed * as meaning "or, if this isn't a VLAN packet...". */ orig_nl = off_nl; switch (linktype) { case DLT_EN10MB: /* check for VLAN */ b0 = gen_cmp(OR_LINK, off_linktype, BPF_H, (bpf_int32) ETHERTYPE_8021Q); /* If a specific VLAN is requested, check VLAN id */ if (vlan_num >= 0) { b1 = gen_mcmp(OR_MACPL, 0, BPF_H, (bpf_int32) vlan_num, 0x0fff); gen_and(b0, b1); b0 = b1; } off_macpl += 4; off_linktype += 4; break; default: bpf_error("no VLAN support for data link type %d", linktype); /*NOTREACHED*/} return (b0); } /* * support for MPLS */ struct block *gen_mpls(label_num) int label_num; { struct block *b0, *b1; /* * Change the offsets to point to the type and data fields within * the MPLS packet. Just increment the offsets, so that we * can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to * capture packets with an outer label of 100000 and an inner * label of 1024. * * XXX - this is a bit of a kludge. See comments in gen_vlan(). */ orig_nl = off_nl; if (label_stack_depth > 0) { /* just match the bottom-of-stack bit clear */ b0 = gen_mcmp(OR_MACPL, orig_nl - 2, BPF_B, 0, 0x01); } else { /* * Indicate that we're checking MPLS-encapsulated headers, * to make sure higher level code generators don't try to * match against IP-related protocols such as Q_ARP, Q_RARP * etc. */ switch (linktype) { case DLT_C_HDLC: /* fall through */ case DLT_EN10MB: b0 = gen_linktype(ETHERTYPE_MPLS); break; case DLT_PPP: b0 = gen_linktype(PPP_MPLS_UCAST); break; /* FIXME add other DLT_s ... * for Frame-Relay/and ATM this may get messy due to SNAP headers * leave it for now */ default: bpf_error("no MPLS support for data link type %d", linktype); b0 = NULL; /*NOTREACHED*/ break; } } /* If a specific MPLS label is requested, check it */ if (label_num >= 0) { label_num = label_num << 12; /* label is shifted 12 bits on the wire */ b1 = gen_mcmp(OR_MACPL, orig_nl, BPF_W, (bpf_int32) label_num, 0xfffff000); /* only compare the first 20 bits */ gen_and(b0, b1); b0 = b1; } off_nl_nosnap += 4; off_nl += 4; label_stack_depth++; return (b0); } /* * Support PPPOE discovery and session. */ struct block *gen_pppoed() { /* check for PPPoE discovery */ return gen_linktype((bpf_int32) ETHERTYPE_PPPOED); } struct block *gen_pppoes() { struct block *b0; /* * Test against the PPPoE session link-layer type. */ b0 = gen_linktype((bpf_int32) ETHERTYPE_PPPOES); /* * Change the offsets to point to the type and data fields within * the PPP packet, and note that this is PPPoE rather than * raw PPP. * * XXX - this is a bit of a kludge. If we were to split the * compiler into a parser that parses an expression and * generates an expression tree, and a code generator that * takes an expression tree (which could come from our * parser or from some other parser) and generates BPF code, * we could perhaps make the offsets parameters of routines * and, in the handler for an "AND" node, pass to subnodes * other than the PPPoE node the adjusted offsets. * * This would mean that "pppoes" would, instead of changing the * behavior of *all* tests after it, change only the behavior * of tests ANDed with it. That would change the documented * semantics of "pppoes", which might break some expressions. * However, it would mean that "(pppoes and ip) or ip" would check * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than * checking only for VLAN-encapsulated IP, so that could still * be considered worth doing; it wouldn't break expressions * that are of the form "pppoes and ..." which I suspect are the * most common expressions involving "pppoes". "pppoes or ..." * doesn't necessarily do what the user would really want, now, * as all the "or ..." tests would be done assuming PPPoE, even * though the "or" could be viewed as meaning "or, if this isn't * a PPPoE packet...". */ orig_linktype = off_linktype; /* save original values */ orig_nl = off_nl; is_pppoes = 1; /* * The "network-layer" protocol is PPPoE, which has a 6-byte * PPPoE header, followed by a PPP packet. * * There is no HDLC encapsulation for the PPP packet (it's * encapsulated in PPPoES instead), so the link-layer type * starts at the first byte of the PPP packet. For PPPoE, * that offset is relative to the beginning of the total * link-layer payload, including any 802.2 LLC header, so * it's 6 bytes past off_nl. */ off_linktype = off_nl + 6; /* * The network-layer offsets are relative to the beginning * of the MAC-layer payload; that's past the 6-byte * PPPoE header and the 2-byte PPP header. */ off_nl = 6 + 2; off_nl_nosnap = 6 + 2; return b0; } struct block *gen_atmfield_code(atmfield, jvalue, jtype, reverse) int atmfield; bpf_int32 jvalue; bpf_u_int32 jtype; int reverse; { struct block *b0; switch (atmfield) { case A_VPI: if (!is_atm) bpf_error("'vpi' supported only on raw ATM"); if (off_vpi == (u_int) - 1) abort(); b0 = gen_ncmp(OR_LINK, off_vpi, BPF_B, 0xffffffff, jtype, reverse, jvalue); break; case A_VCI: if (!is_atm) bpf_error("'vci' supported only on raw ATM"); if (off_vci == (u_int) - 1) abort(); b0 = gen_ncmp(OR_LINK, off_vci, BPF_H, 0xffffffff, jtype, reverse, jvalue); break; case A_PROTOTYPE: if (off_proto == (u_int) - 1) abort(); /* XXX - this isn't on FreeBSD */ b0 = gen_ncmp(OR_LINK, off_proto, BPF_B, 0x0f, jtype, reverse, jvalue); break; case A_MSGTYPE: if (off_payload == (u_int) - 1) abort(); b0 = gen_ncmp(OR_LINK, off_payload + MSG_TYPE_POS, BPF_B, 0xffffffff, jtype, reverse, jvalue); break; case A_CALLREFTYPE: if (!is_atm) bpf_error("'callref' supported only on raw ATM"); if (off_proto == (u_int) - 1) abort(); b0 = gen_ncmp(OR_LINK, off_proto, BPF_B, 0xffffffff, jtype, reverse, jvalue); break; default: abort(); } return b0; } struct block *gen_atmtype_abbrev(type) int type; { struct block *b0, *b1; switch (type) { case A_METAC: /* Get all packets in Meta signalling Circuit */ if (!is_atm) bpf_error("'metac' supported only on raw ATM"); b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code(A_VCI, 1, BPF_JEQ, 0); gen_and(b0, b1); break; case A_BCC: /* Get all packets in Broadcast Circuit */ if (!is_atm) bpf_error("'bcc' supported only on raw ATM"); b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code(A_VCI, 2, BPF_JEQ, 0); gen_and(b0, b1); break; case A_OAMF4SC: /* Get all cells in Segment OAM F4 circuit */ if (!is_atm) bpf_error("'oam4sc' supported only on raw ATM"); b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code(A_VCI, 3, BPF_JEQ, 0); gen_and(b0, b1); break; case A_OAMF4EC: /* Get all cells in End-to-End OAM F4 Circuit */ if (!is_atm) bpf_error("'oam4ec' supported only on raw ATM"); b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code(A_VCI, 4, BPF_JEQ, 0); gen_and(b0, b1); break; case A_SC: /* Get all packets in connection Signalling Circuit */ if (!is_atm) bpf_error("'sc' supported only on raw ATM"); b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code(A_VCI, 5, BPF_JEQ, 0); gen_and(b0, b1); break; case A_ILMIC: /* Get all packets in ILMI Circuit */ if (!is_atm) bpf_error("'ilmic' supported only on raw ATM"); b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); b1 = gen_atmfield_code(A_VCI, 16, BPF_JEQ, 0); gen_and(b0, b1); break; case A_LANE: /* Get all LANE packets */ if (!is_atm) bpf_error("'lane' supported only on raw ATM"); b1 = gen_atmfield_code(A_PROTOTYPE, PT_LANE, BPF_JEQ, 0); /* * Arrange that all subsequent tests assume LANE * rather than LLC-encapsulated packets, and set * the offsets appropriately for LANE-encapsulated * Ethernet. * * "off_mac" is the offset of the Ethernet header, * which is 2 bytes past the ATM pseudo-header * (skipping the pseudo-header and 2-byte LE Client * field). The other offsets are Ethernet offsets * relative to "off_mac". */ is_lane = 1; off_mac = off_payload + 2; /* MAC header */ off_linktype = off_mac + 12; off_macpl = off_mac + 14; /* Ethernet */ off_nl = 0; /* Ethernet II */ off_nl_nosnap = 3; /* 802.3+802.2 */ break; case A_LLC: /* Get all LLC-encapsulated packets */ if (!is_atm) bpf_error("'llc' supported only on raw ATM"); b1 = gen_atmfield_code(A_PROTOTYPE, PT_LLC, BPF_JEQ, 0); is_lane = 0; break; default: abort(); } return b1; } /* * Filtering for MTP2 messages based on li value * FISU, length is null * LSSU, length is 1 or 2 * MSU, length is 3 or more */ struct block *gen_mtp2type_abbrev(type) int type; { struct block *b0, *b1; switch (type) { case M_FISU: if ((linktype != DLT_MTP2) && (linktype != DLT_ERF) && (linktype != DLT_MTP2_WITH_PHDR)) bpf_error("'fisu' supported only on MTP2"); /* gen_ncmp(offrel, offset, size, mask, jtype, reverse, value) */ b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0); break; case M_LSSU: if ((linktype != DLT_MTP2) && (linktype != DLT_ERF) && (linktype != DLT_MTP2_WITH_PHDR)) bpf_error("'lssu' supported only on MTP2"); b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 1, 2); b1 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 0, 0); gen_and(b1, b0); break; case M_MSU: if ((linktype != DLT_MTP2) && (linktype != DLT_ERF) && (linktype != DLT_MTP2_WITH_PHDR)) bpf_error("'msu' supported only on MTP2"); b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 0, 2); break; default: abort(); } return b0; } struct block *gen_mtp3field_code(mtp3field, jvalue, jtype, reverse) int mtp3field; bpf_u_int32 jvalue; bpf_u_int32 jtype; int reverse; { struct block *b0; bpf_u_int32 val1, val2, val3; switch (mtp3field) { case M_SIO: if (off_sio == (u_int) - 1) bpf_error("'sio' supported only on SS7"); /* sio coded on 1 byte so max value 255 */ if (jvalue > 255) bpf_error("sio value %u too big; max value = 255", jvalue); b0 = gen_ncmp(OR_PACKET, off_sio, BPF_B, 0xffffffff, (u_int) jtype, reverse, (u_int) jvalue); break; case M_OPC: if (off_opc == (u_int) - 1) bpf_error("'opc' supported only on SS7"); /* opc coded on 14 bits so max value 16383 */ if (jvalue > 16383) bpf_error("opc value %u too big; max value = 16383", jvalue); /* the following instructions are made to convert jvalue * to the form used to write opc in an ss7 message*/ val1 = jvalue & 0x00003c00; val1 = val1 >> 10; val2 = jvalue & 0x000003fc; val2 = val2 << 6; val3 = jvalue & 0x00000003; val3 = val3 << 22; jvalue = val1 + val2 + val3; b0 = gen_ncmp(OR_PACKET, off_opc, BPF_W, 0x00c0ff0f, (u_int) jtype, reverse, (u_int) jvalue); break; case M_DPC: if (off_dpc == (u_int) - 1) bpf_error("'dpc' supported only on SS7"); /* dpc coded on 14 bits so max value 16383 */ if (jvalue > 16383) bpf_error("dpc value %u too big; max value = 16383", jvalue); /* the following instructions are made to convert jvalue * to the forme used to write dpc in an ss7 message*/ val1 = jvalue & 0x000000ff; val1 = val1 << 24; val2 = jvalue & 0x00003f00; val2 = val2 << 8; jvalue = val1 + val2; b0 = gen_ncmp(OR_PACKET, off_dpc, BPF_W, 0xff3f0000, (u_int) jtype, reverse, (u_int) jvalue); break; case M_SLS: if (off_sls == (u_int) - 1) bpf_error("'sls' supported only on SS7"); /* sls coded on 4 bits so max value 15 */ if (jvalue > 15) bpf_error("sls value %u too big; max value = 15", jvalue); /* the following instruction is made to convert jvalue * to the forme used to write sls in an ss7 message*/ jvalue = jvalue << 4; b0 = gen_ncmp(OR_PACKET, off_sls, BPF_B, 0xf0, (u_int) jtype, reverse, (u_int) jvalue); break; default: abort(); } return b0; } static struct block *gen_msg_abbrev(type) int type; { struct block *b1; /* * Q.2931 signalling protocol messages for handling virtual circuits * establishment and teardown */ switch (type) { case A_SETUP: b1 = gen_atmfield_code(A_MSGTYPE, SETUP, BPF_JEQ, 0); break; case A_CALLPROCEED: b1 = gen_atmfield_code(A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0); break; case A_CONNECT: b1 = gen_atmfield_code(A_MSGTYPE, CONNECT, BPF_JEQ, 0); break; case A_CONNECTACK: b1 = gen_atmfield_code(A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0); break; case A_RELEASE: b1 = gen_atmfield_code(A_MSGTYPE, RELEASE, BPF_JEQ, 0); break; case A_RELEASE_DONE: b1 = gen_atmfield_code(A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0); break; default: abort(); } return b1; } struct block *gen_atmmulti_abbrev(type) int type; { struct block *b0, *b1; switch (type) { case A_OAM: if (!is_atm) bpf_error("'oam' supported only on raw ATM"); b1 = gen_atmmulti_abbrev(A_OAMF4); break; case A_OAMF4: if (!is_atm) bpf_error("'oamf4' supported only on raw ATM"); /* OAM F4 type */ b0 = gen_atmfield_code(A_VCI, 3, BPF_JEQ, 0); b1 = gen_atmfield_code(A_VCI, 4, BPF_JEQ, 0); gen_or(b0, b1); b0 = gen_atmfield_code(A_VPI, 0, BPF_JEQ, 0); gen_and(b0, b1); break; case A_CONNECTMSG: /* * Get Q.2931 signalling messages for switched * virtual connection */ if (!is_atm) bpf_error("'connectmsg' supported only on raw ATM"); b0 = gen_msg_abbrev(A_SETUP); b1 = gen_msg_abbrev(A_CALLPROCEED); gen_or(b0, b1); b0 = gen_msg_abbrev(A_CONNECT); gen_or(b0, b1); b0 = gen_msg_abbrev(A_CONNECTACK); gen_or(b0, b1); b0 = gen_msg_abbrev(A_RELEASE); gen_or(b0, b1); b0 = gen_msg_abbrev(A_RELEASE_DONE); gen_or(b0, b1); b0 = gen_atmtype_abbrev(A_SC); gen_and(b0, b1); break; case A_METACONNECT: if (!is_atm) bpf_error("'metaconnect' supported only on raw ATM"); b0 = gen_msg_abbrev(A_SETUP); b1 = gen_msg_abbrev(A_CALLPROCEED); gen_or(b0, b1); b0 = gen_msg_abbrev(A_CONNECT); gen_or(b0, b1); b0 = gen_msg_abbrev(A_RELEASE); gen_or(b0, b1); b0 = gen_msg_abbrev(A_RELEASE_DONE); gen_or(b0, b1); b0 = gen_atmtype_abbrev(A_METAC); gen_and(b0, b1); break; default: abort(); } return b1; }