1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2001 Charles Mott <[email protected]>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31 /*
32 * Alias_local.h contains the function prototypes for alias.c,
33 * alias_db.c, alias_util.c and alias_ftp.c, alias_irc.c (as well
34 * as any future add-ons). It also includes macros, globals and
35 * struct definitions shared by more than one alias*.c file.
36 *
37 * This include file is intended to be used only within the aliasing
38 * software. Outside world interfaces are defined in alias.h
39 *
40 * This software is placed into the public domain with no restrictions
41 * on its distribution.
42 *
43 * Initial version: August, 1996 (cjm)
44 *
45 * <updated several times by original author and Eivind Eklund>
46 */
47
48 #ifndef _ALIAS_LOCAL_H_
49 #define _ALIAS_LOCAL_H_
50
51 #include <sys/types.h>
52 #include <sys/sysctl.h>
53
54 #ifdef _KERNEL
55 #include <sys/malloc.h>
56 #include <sys/param.h>
57 #include <sys/lock.h>
58 #include <sys/mutex.h>
59
60 /* XXX: LibAliasSetTarget() uses this constant. */
61 #define INADDR_NONE 0xffffffff
62
63 #include <netinet/libalias/alias_sctp.h>
64 #else
65 #include "alias_sctp.h"
66 #endif
67
68 /* Sizes of input and output link tables */
69 #define LINK_TABLE_OUT_SIZE 4001
70 #define LINK_TABLE_IN_SIZE 4001
71
72 #define GET_ALIAS_PORT -1
73 #define GET_ALIAS_ID GET_ALIAS_PORT
74
75 #ifdef _KERNEL
76 #define INET_NTOA_BUF(buf) (buf)
77 #else
78 #define INET_NTOA_BUF(buf) (buf), sizeof(buf)
79 #endif
80
81 struct proxy_entry;
82
83 struct libalias {
84 LIST_ENTRY(libalias) instancelist;
85
86 int packetAliasMode; /* Mode flags */
87 /* - documented in alias.h */
88
89 struct in_addr aliasAddress; /* Address written onto source */
90 /* field of IP packet. */
91
92 struct in_addr targetAddress; /* IP address incoming packets */
93 /* are sent to if no aliasing */
94 /* link already exists */
95
96 struct in_addr nullAddress; /* Used as a dummy parameter for */
97 /* some function calls */
98
99 LIST_HEAD (, alias_link) linkTableOut[LINK_TABLE_OUT_SIZE];
100 /* Lookup table of pointers to */
101 /* chains of link records. Each */
102
103 LIST_HEAD (, alias_link) linkTableIn[LINK_TABLE_IN_SIZE];
104 /* link record is doubly indexed */
105 /* into input and output lookup */
106 /* tables. */
107
108 /* Link statistics */
109 int icmpLinkCount;
110 int udpLinkCount;
111 int tcpLinkCount;
112 int pptpLinkCount;
113 int protoLinkCount;
114 int fragmentIdLinkCount;
115 int fragmentPtrLinkCount;
116 int sockCount;
117
118 int cleanupIndex; /* Index to chain of link table */
119 /* being inspected for old links */
120
121 int timeStamp; /* System time in seconds for */
122 /* current packet */
123
124 int lastCleanupTime; /* Last time
125 * IncrementalCleanup() */
126 /* was called */
127
128 int deleteAllLinks; /* If equal to zero, DeleteLink() */
129 /* will not remove permanent links */
130
131 /* log descriptor */
132 #ifdef _KERNEL
133 char *logDesc;
134 #else
135 FILE *logDesc;
136 #endif
137 /* statistics monitoring */
138
139 int newDefaultLink; /* Indicates if a new aliasing */
140 /* link has been created after a */
141 /* call to PacketAliasIn/Out(). */
142
143 #ifndef NO_FW_PUNCH
144 int fireWallFD; /* File descriptor to be able to */
145 /* control firewall. Opened by */
146 /* PacketAliasSetMode on first */
147 /* setting the PKT_ALIAS_PUNCH_FW */
148 /* flag. */
149 int fireWallBaseNum; /* The first firewall entry
150 * free for our use */
151 int fireWallNumNums; /* How many entries can we
152 * use? */
153 int fireWallActiveNum; /* Which entry did we last
154 * use? */
155 char *fireWallField; /* bool array for entries */
156 #endif
157
158 unsigned int skinnyPort; /* TCP port used by the Skinny */
159 /* protocol. */
160
161 struct proxy_entry *proxyList;
162
163 struct in_addr true_addr; /* in network byte order. */
164 u_short true_port; /* in host byte order. */
165
166 /*
167 * sctp code support
168 */
169
170 /* counts associations that have progressed to UP and not yet removed */
171 int sctpLinkCount;
172 #ifdef _KERNEL
173 /* timing queue for keeping track of association timeouts */
174 struct sctp_nat_timer sctpNatTimer;
175
176 /* size of hash table used in this instance */
177 u_int sctpNatTableSize;
178
179 /*
180 * local look up table sorted by l_vtag/l_port
181 */
182 LIST_HEAD(sctpNatTableL, sctp_nat_assoc) *sctpTableLocal;
183 /*
184 * global look up table sorted by g_vtag/g_port
185 */
186 LIST_HEAD(sctpNatTableG, sctp_nat_assoc) *sctpTableGlobal;
187
188 /*
189 * avoid races in libalias: every public function has to use it.
190 */
191 struct mtx mutex;
192 #endif
193 };
194
195 /* Macros */
196
197 #ifdef _KERNEL
198 #define LIBALIAS_LOCK_INIT(l) \
199 mtx_init(&l->mutex, "per-instance libalias mutex", NULL, MTX_DEF)
200 #define LIBALIAS_LOCK_ASSERT(l) mtx_assert(&l->mutex, MA_OWNED)
201 #define LIBALIAS_LOCK(l) mtx_lock(&l->mutex)
202 #define LIBALIAS_UNLOCK(l) mtx_unlock(&l->mutex)
203 #define LIBALIAS_LOCK_DESTROY(l) mtx_destroy(&l->mutex)
204 #else
205 #define LIBALIAS_LOCK_INIT(l)
206 #define LIBALIAS_LOCK_ASSERT(l)
207 #define LIBALIAS_LOCK(l)
208 #define LIBALIAS_UNLOCK(l)
209 #define LIBALIAS_LOCK_DESTROY(l)
210 #endif
211
212 /*
213 * The following macro is used to update an
214 * internet checksum. "delta" is a 32-bit
215 * accumulation of all the changes to the
216 * checksum (adding in new 16-bit words and
217 * subtracting out old words), and "cksum"
218 * is the checksum value to be updated.
219 */
220 #define ADJUST_CHECKSUM(acc, cksum) \
221 do { \
222 acc += cksum; \
223 if (acc < 0) { \
224 acc = -acc; \
225 acc = (acc >> 16) + (acc & 0xffff); \
226 acc += acc >> 16; \
227 cksum = (u_short) ~acc; \
228 } else { \
229 acc = (acc >> 16) + (acc & 0xffff); \
230 acc += acc >> 16; \
231 cksum = (u_short) acc; \
232 } \
233 } while (0)
234
235
236 /* Prototypes */
237
238 /*
239 * SctpFunction prototypes
240 *
241 */
242 void AliasSctpInit(struct libalias *la);
243 void AliasSctpTerm(struct libalias *la);
244 int SctpAlias(struct libalias *la, struct ip *ip, int direction);
245
246 /*
247 * We do not calculate TCP checksums when libalias is a kernel
248 * module, since it has no idea about checksum offloading.
249 * If TCP data has changed, then we just set checksum to zero,
250 * and caller must recalculate it himself.
251 * In case if libalias will edit UDP data, the same approach
252 * should be used.
253 */
254 #ifndef _KERNEL
255 u_short IpChecksum(struct ip *_pip);
256 u_short TcpChecksum(struct ip *_pip);
257 #endif
258 void
259 DifferentialChecksum(u_short * _cksum, void * _new, void * _old, int _n);
260
261 /* Internal data access */
262 struct alias_link *
263 AddLink(struct libalias *la, struct in_addr src_addr, struct in_addr dst_addr,
264 struct in_addr alias_addr, u_short src_port, u_short dst_port,
265 int alias_param, int link_type);
266 struct alias_link *
267 FindIcmpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
268 u_short _id_alias, int _create);
269 struct alias_link *
270 FindIcmpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
271 u_short _id, int _create);
272 struct alias_link *
273 FindFragmentIn1(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
274 u_short _ip_id);
275 struct alias_link *
276 FindFragmentIn2(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
277 u_short _ip_id);
278 struct alias_link *
279 AddFragmentPtrLink(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
280 struct alias_link *
281 FindFragmentPtr(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
282 struct alias_link *
283 FindProtoIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
284 u_char _proto);
285 struct alias_link *
286 FindProtoOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
287 u_char _proto);
288 struct alias_link *
289 FindUdpTcpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
290 u_short _dst_port, u_short _alias_port, u_char _proto, int _create);
291 struct alias_link *
292 FindUdpTcpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
293 u_short _src_port, u_short _dst_port, u_char _proto, int _create);
294 struct alias_link *
295 AddPptp(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
296 struct in_addr _alias_addr, u_int16_t _src_call_id);
297 struct alias_link *
298 FindPptpOutByCallId(struct libalias *la, struct in_addr _src_addr,
299 struct in_addr _dst_addr, u_int16_t _src_call_id);
300 struct alias_link *
301 FindPptpInByCallId(struct libalias *la, struct in_addr _dst_addr,
302 struct in_addr _alias_addr, u_int16_t _dst_call_id);
303 struct alias_link *
304 FindPptpOutByPeerCallId(struct libalias *la, struct in_addr _src_addr,
305 struct in_addr _dst_addr, u_int16_t _dst_call_id);
306 struct alias_link *
307 FindPptpInByPeerCallId(struct libalias *la, struct in_addr _dst_addr,
308 struct in_addr _alias_addr, u_int16_t _alias_call_id);
309 struct alias_link *
310 FindRtspOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
311 u_short _src_port, u_short _alias_port, u_char _proto);
312 struct in_addr
313 FindOriginalAddress(struct libalias *la, struct in_addr _alias_addr);
314 struct in_addr
315 FindAliasAddress(struct libalias *la, struct in_addr _original_addr);
316 struct in_addr
317 FindSctpRedirectAddress(struct libalias *la, struct sctp_nat_msg *sm);
318
319 /* External data access/modification */
320 int
321 FindNewPortGroup(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
322 u_short _src_port, u_short _dst_port, u_short _port_count,
323 u_char _proto, u_char _align);
324 void GetFragmentAddr(struct alias_link *_lnk, struct in_addr *_src_addr);
325 void SetFragmentAddr(struct alias_link *_lnk, struct in_addr _src_addr);
326 void GetFragmentPtr(struct alias_link *_lnk, char **_fptr);
327 void SetFragmentPtr(struct alias_link *_lnk, char *fptr);
328 void SetStateIn(struct alias_link *_lnk, int _state);
329 void SetStateOut(struct alias_link *_lnk, int _state);
330 int GetStateIn (struct alias_link *_lnk);
331 int GetStateOut(struct alias_link *_lnk);
332 struct in_addr
333 GetOriginalAddress(struct alias_link *_lnk);
334 struct in_addr
335 GetDestAddress(struct alias_link *_lnk);
336 struct in_addr
337 GetAliasAddress(struct alias_link *_lnk);
338 struct in_addr
339 GetDefaultAliasAddress(struct libalias *la);
340 void SetDefaultAliasAddress(struct libalias *la, struct in_addr _alias_addr);
341 u_short GetOriginalPort(struct alias_link *_lnk);
342 u_short GetAliasPort(struct alias_link *_lnk);
343 struct in_addr
344 GetProxyAddress(struct alias_link *_lnk);
345 void SetProxyAddress(struct alias_link *_lnk, struct in_addr _addr);
346 u_short GetProxyPort(struct alias_link *_lnk);
347 void SetProxyPort(struct alias_link *_lnk, u_short _port);
348 void SetAckModified(struct alias_link *_lnk);
349 int GetAckModified(struct alias_link *_lnk);
350 int GetDeltaAckIn(u_long, struct alias_link *_lnk);
351 int GetDeltaSeqOut(u_long, struct alias_link *lnk);
352 void AddSeq(struct alias_link *lnk, int delta, u_int ip_hl,
353 u_short ip_len, u_long th_seq, u_int th_off);
354 void SetExpire (struct alias_link *_lnk, int _expire);
355 void ClearCheckNewLink(struct libalias *la);
356 void SetProtocolFlags(struct alias_link *_lnk, int _pflags);
357 int GetProtocolFlags(struct alias_link *_lnk);
358 void SetDestCallId(struct alias_link *_lnk, u_int16_t _cid);
359
360 #ifndef NO_FW_PUNCH
361 void PunchFWHole(struct alias_link *_lnk);
362
363 #endif
364
365 /* Housekeeping function */
366 void HouseKeeping(struct libalias *);
367
368 /* Tcp specific routines */
369 /* lint -save -library Suppress flexelint warnings */
370
371 /* Transparent proxy routines */
372 int
373 ProxyCheck(struct libalias *la, struct in_addr *proxy_server_addr,
374 u_short * proxy_server_port, struct in_addr src_addr,
375 struct in_addr dst_addr, u_short dst_port, u_char ip_p);
376 void
377 ProxyModify(struct libalias *la, struct alias_link *_lnk, struct ip *_pip,
378 int _maxpacketsize, int _proxy_type);
379
380 enum alias_tcp_state {
381 ALIAS_TCP_STATE_NOT_CONNECTED,
382 ALIAS_TCP_STATE_CONNECTED,
383 ALIAS_TCP_STATE_DISCONNECTED
384 };
385
386 #if defined(_NETINET_IP_H_)
387 static __inline void *
ip_next(struct ip * iphdr)388 ip_next(struct ip *iphdr)
389 {
390 char *p = (char *)iphdr;
391 return (&p[iphdr->ip_hl * 4]);
392 }
393 #endif
394
395 #if defined(_NETINET_TCP_H_)
396 static __inline void *
tcp_next(struct tcphdr * tcphdr)397 tcp_next(struct tcphdr *tcphdr)
398 {
399 char *p = (char *)tcphdr;
400 return (&p[tcphdr->th_off * 4]);
401 }
402 #endif
403
404 #if defined(_NETINET_UDP_H_)
405 static __inline void *
udp_next(struct udphdr * udphdr)406 udp_next(struct udphdr *udphdr)
407 {
408 return ((void *)(udphdr + 1));
409 }
410 #endif
411
412 #endif /* !_ALIAS_LOCAL_H_ */
413