1 #ifndef __LINUX_NETFILTER_H 2 #define __LINUX_NETFILTER_H 3 4 #ifdef __KERNEL__ 5 #include <linux/init.h> 6 #include <linux/types.h> 7 #include <linux/skbuff.h> 8 #include <linux/net.h> 9 #include <linux/if.h> 10 #include <linux/wait.h> 11 #include <linux/list.h> 12 #endif 13 #include <linux/compiler.h> 14 15 /* Responses from hook functions. */ 16 #define NF_DROP 0 17 #define NF_ACCEPT 1 18 #define NF_STOLEN 2 19 #define NF_QUEUE 3 20 #define NF_REPEAT 4 21 #define NF_STOP 5 22 #define NF_MAX_VERDICT NF_STOP 23 24 /* we overload the higher bits for encoding auxiliary data such as the queue 25 * number. Not nice, but better than additional function arguments. */ 26 #define NF_VERDICT_MASK 0x0000ffff 27 #define NF_VERDICT_BITS 16 28 29 #define NF_VERDICT_QMASK 0xffff0000 30 #define NF_VERDICT_QBITS 16 31 32 #define NF_QUEUE_NR(x) (((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK) | NF_QUEUE) 33 34 /* only for userspace compatibility */ 35 #ifndef __KERNEL__ 36 /* Generic cache responses from hook functions. 37 <= 0x2000 is used for protocol-flags. */ 38 #define NFC_UNKNOWN 0x4000 39 #define NFC_ALTERED 0x8000 40 #endif 41 42 #ifdef __KERNEL__ 43 #ifdef CONFIG_NETFILTER 44 45 extern void netfilter_init(void); 46 47 /* Largest hook number + 1 */ 48 #define NF_MAX_HOOKS 8 49 50 struct sk_buff; 51 struct net_device; 52 53 typedef unsigned int nf_hookfn(unsigned int hooknum, 54 struct sk_buff **skb, 55 const struct net_device *in, 56 const struct net_device *out, 57 int (*okfn)(struct sk_buff *)); 58 59 struct nf_hook_ops 60 { 61 struct list_head list; 62 63 /* User fills in from here down. */ 64 nf_hookfn *hook; 65 struct module *owner; 66 int pf; 67 int hooknum; 68 /* Hooks are ordered in ascending priority. */ 69 int priority; 70 }; 71 72 struct nf_sockopt_ops 73 { 74 struct list_head list; 75 76 int pf; 77 78 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 79 int set_optmin; 80 int set_optmax; 81 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 82 int (*compat_set)(struct sock *sk, int optval, 83 void __user *user, unsigned int len); 84 85 int get_optmin; 86 int get_optmax; 87 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 88 int (*compat_get)(struct sock *sk, int optval, 89 void __user *user, int *len); 90 91 /* Use the module struct to lock set/get code in place */ 92 struct module *owner; 93 }; 94 95 /* Each queued (to userspace) skbuff has one of these. */ 96 struct nf_info 97 { 98 /* The ops struct which sent us to userspace. */ 99 struct nf_hook_ops *elem; 100 101 /* If we're sent to userspace, this keeps housekeeping info */ 102 int pf; 103 unsigned int hook; 104 struct net_device *indev, *outdev; 105 int (*okfn)(struct sk_buff *); 106 }; 107 108 /* Function to register/unregister hook points. */ 109 int nf_register_hook(struct nf_hook_ops *reg); 110 void nf_unregister_hook(struct nf_hook_ops *reg); 111 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 112 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 113 114 /* Functions to register get/setsockopt ranges (non-inclusive). You 115 need to check permissions yourself! */ 116 int nf_register_sockopt(struct nf_sockopt_ops *reg); 117 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 118 119 #ifdef CONFIG_SYSCTL 120 /* Sysctl registration */ 121 struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path, 122 struct ctl_table *table); 123 void nf_unregister_sysctl_table(struct ctl_table_header *header, 124 struct ctl_table *table); 125 extern struct ctl_table nf_net_netfilter_sysctl_path[]; 126 extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[]; 127 #endif /* CONFIG_SYSCTL */ 128 129 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 130 131 /* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will 132 * disappear once iptables is replaced with pkttables. Please DO NOT use them 133 * for any new code! */ 134 #define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */ 135 #define NF_LOG_TCPOPT 0x02 /* Log TCP options */ 136 #define NF_LOG_IPOPT 0x04 /* Log IP options */ 137 #define NF_LOG_UID 0x08 /* Log UID owning local socket */ 138 #define NF_LOG_MASK 0x0f 139 140 #define NF_LOG_TYPE_LOG 0x01 141 #define NF_LOG_TYPE_ULOG 0x02 142 143 struct nf_loginfo { 144 u_int8_t type; 145 union { 146 struct { 147 u_int32_t copy_len; 148 u_int16_t group; 149 u_int16_t qthreshold; 150 } ulog; 151 struct { 152 u_int8_t level; 153 u_int8_t logflags; 154 } log; 155 } u; 156 }; 157 158 typedef void nf_logfn(unsigned int pf, 159 unsigned int hooknum, 160 const struct sk_buff *skb, 161 const struct net_device *in, 162 const struct net_device *out, 163 const struct nf_loginfo *li, 164 const char *prefix); 165 166 struct nf_logger { 167 struct module *me; 168 nf_logfn *logfn; 169 char *name; 170 }; 171 172 /* Function to register/unregister log function. */ 173 int nf_log_register(int pf, struct nf_logger *logger); 174 void nf_log_unregister(struct nf_logger *logger); 175 void nf_log_unregister_pf(int pf); 176 177 /* Calls the registered backend logging function */ 178 void nf_log_packet(int pf, 179 unsigned int hooknum, 180 const struct sk_buff *skb, 181 const struct net_device *in, 182 const struct net_device *out, 183 struct nf_loginfo *li, 184 const char *fmt, ...); 185 186 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb, 187 struct net_device *indev, struct net_device *outdev, 188 int (*okfn)(struct sk_buff *), int thresh); 189 190 /** 191 * nf_hook_thresh - call a netfilter hook 192 * 193 * Returns 1 if the hook has allowed the packet to pass. The function 194 * okfn must be invoked by the caller in this case. Any other return 195 * value indicates the packet has been consumed by the hook. 196 */ 197 static inline int nf_hook_thresh(int pf, unsigned int hook, 198 struct sk_buff **pskb, 199 struct net_device *indev, 200 struct net_device *outdev, 201 int (*okfn)(struct sk_buff *), int thresh, 202 int cond) 203 { 204 if (!cond) 205 return 1; 206 #ifndef CONFIG_NETFILTER_DEBUG 207 if (list_empty(&nf_hooks[pf][hook])) 208 return 1; 209 #endif 210 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh); 211 } 212 213 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 214 struct net_device *indev, struct net_device *outdev, 215 int (*okfn)(struct sk_buff *)) 216 { 217 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1); 218 } 219 220 /* Activate hook; either okfn or kfree_skb called, unless a hook 221 returns NF_STOLEN (in which case, it's up to the hook to deal with 222 the consequences). 223 224 Returns -ERRNO if packet dropped. Zero means queued, stolen or 225 accepted. 226 */ 227 228 /* RR: 229 > I don't want nf_hook to return anything because people might forget 230 > about async and trust the return value to mean "packet was ok". 231 232 AK: 233 Just document it clearly, then you can expect some sense from kernel 234 coders :) 235 */ 236 237 /* This is gross, but inline doesn't cut it for avoiding the function 238 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 239 240 /* HX: It's slightly less gross now. */ 241 242 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 243 ({int __ret; \ 244 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\ 245 __ret = (okfn)(skb); \ 246 __ret;}) 247 248 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 249 ({int __ret; \ 250 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 251 __ret = (okfn)(skb); \ 252 __ret;}) 253 254 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 255 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 256 257 /* Call setsockopt() */ 258 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 259 int len); 260 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 261 int *len); 262 263 int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 264 char __user *opt, int len); 265 int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 266 char __user *opt, int *len); 267 268 /* Packet queuing */ 269 struct nf_queue_handler { 270 int (*outfn)(struct sk_buff *skb, struct nf_info *info, 271 unsigned int queuenum, void *data); 272 void *data; 273 char *name; 274 }; 275 extern int nf_register_queue_handler(int pf, 276 struct nf_queue_handler *qh); 277 extern int nf_unregister_queue_handler(int pf, 278 struct nf_queue_handler *qh); 279 extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh); 280 extern void nf_reinject(struct sk_buff *skb, 281 struct nf_info *info, 282 unsigned int verdict); 283 284 /* FIXME: Before cache is ever used, this must be implemented for real. */ 285 extern void nf_invalidate_cache(int pf); 286 287 /* Call this before modifying an existing packet: ensures it is 288 modifiable and linear to the point you care about (writable_len). 289 Returns true or false. */ 290 extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len); 291 292 static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to) 293 { 294 __be32 diff[] = { ~from, to }; 295 296 *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum))); 297 } 298 299 static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to) 300 { 301 nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to); 302 } 303 304 extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, 305 __be32 from, __be32 to, int pseudohdr); 306 307 static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, 308 __be16 from, __be16 to, int pseudohdr) 309 { 310 nf_proto_csum_replace4(sum, skb, (__force __be32)from, 311 (__force __be32)to, pseudohdr); 312 } 313 314 struct nf_afinfo { 315 unsigned short family; 316 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 317 unsigned int dataoff, u_int8_t protocol); 318 void (*saveroute)(const struct sk_buff *skb, 319 struct nf_info *info); 320 int (*reroute)(struct sk_buff **skb, 321 const struct nf_info *info); 322 int route_key_size; 323 }; 324 325 extern struct nf_afinfo *nf_afinfo[]; 326 static inline struct nf_afinfo *nf_get_afinfo(unsigned short family) 327 { 328 return rcu_dereference(nf_afinfo[family]); 329 } 330 331 static inline __sum16 332 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 333 u_int8_t protocol, unsigned short family) 334 { 335 struct nf_afinfo *afinfo; 336 __sum16 csum = 0; 337 338 rcu_read_lock(); 339 afinfo = nf_get_afinfo(family); 340 if (afinfo) 341 csum = afinfo->checksum(skb, hook, dataoff, protocol); 342 rcu_read_unlock(); 343 return csum; 344 } 345 346 extern int nf_register_afinfo(struct nf_afinfo *afinfo); 347 extern void nf_unregister_afinfo(struct nf_afinfo *afinfo); 348 349 #define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info)) 350 351 #include <net/flow.h> 352 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 353 354 static inline void 355 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 356 { 357 #if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED) 358 void (*decodefn)(struct sk_buff *, struct flowi *); 359 360 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 361 decodefn(skb, fl); 362 #endif 363 } 364 365 #ifdef CONFIG_PROC_FS 366 #include <linux/proc_fs.h> 367 extern struct proc_dir_entry *proc_net_netfilter; 368 #endif 369 370 #else /* !CONFIG_NETFILTER */ 371 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 372 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 373 static inline int nf_hook_thresh(int pf, unsigned int hook, 374 struct sk_buff **pskb, 375 struct net_device *indev, 376 struct net_device *outdev, 377 int (*okfn)(struct sk_buff *), int thresh, 378 int cond) 379 { 380 return okfn(*pskb); 381 } 382 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 383 struct net_device *indev, struct net_device *outdev, 384 int (*okfn)(struct sk_buff *)) 385 { 386 return 1; 387 } 388 struct flowi; 389 static inline void 390 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 391 #endif /*CONFIG_NETFILTER*/ 392 393 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 394 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 395 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 396 extern void (*nf_ct_destroy)(struct nf_conntrack *); 397 #else 398 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 399 #endif 400 401 #endif /*__KERNEL__*/ 402 #endif /*__LINUX_NETFILTER_H*/ 403