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 /* Number of users inside set() or get(). */ 92 unsigned int use; 93 struct task_struct *cleanup_task; 94 }; 95 96 /* Each queued (to userspace) skbuff has one of these. */ 97 struct nf_info 98 { 99 /* The ops struct which sent us to userspace. */ 100 struct nf_hook_ops *elem; 101 102 /* If we're sent to userspace, this keeps housekeeping info */ 103 int pf; 104 unsigned int hook; 105 struct net_device *indev, *outdev; 106 int (*okfn)(struct sk_buff *); 107 }; 108 109 /* Function to register/unregister hook points. */ 110 int nf_register_hook(struct nf_hook_ops *reg); 111 void nf_unregister_hook(struct nf_hook_ops *reg); 112 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 113 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 114 115 /* Functions to register get/setsockopt ranges (non-inclusive). You 116 need to check permissions yourself! */ 117 int nf_register_sockopt(struct nf_sockopt_ops *reg); 118 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 119 120 #ifdef CONFIG_SYSCTL 121 /* Sysctl registration */ 122 struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path, 123 struct ctl_table *table); 124 void nf_unregister_sysctl_table(struct ctl_table_header *header, 125 struct ctl_table *table); 126 extern struct ctl_table nf_net_netfilter_sysctl_path[]; 127 extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[]; 128 #endif /* CONFIG_SYSCTL */ 129 130 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 131 132 /* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will 133 * disappear once iptables is replaced with pkttables. Please DO NOT use them 134 * for any new code! */ 135 #define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */ 136 #define NF_LOG_TCPOPT 0x02 /* Log TCP options */ 137 #define NF_LOG_IPOPT 0x04 /* Log IP options */ 138 #define NF_LOG_UID 0x08 /* Log UID owning local socket */ 139 #define NF_LOG_MASK 0x0f 140 141 #define NF_LOG_TYPE_LOG 0x01 142 #define NF_LOG_TYPE_ULOG 0x02 143 144 struct nf_loginfo { 145 u_int8_t type; 146 union { 147 struct { 148 u_int32_t copy_len; 149 u_int16_t group; 150 u_int16_t qthreshold; 151 } ulog; 152 struct { 153 u_int8_t level; 154 u_int8_t logflags; 155 } log; 156 } u; 157 }; 158 159 typedef void nf_logfn(unsigned int pf, 160 unsigned int hooknum, 161 const struct sk_buff *skb, 162 const struct net_device *in, 163 const struct net_device *out, 164 const struct nf_loginfo *li, 165 const char *prefix); 166 167 struct nf_logger { 168 struct module *me; 169 nf_logfn *logfn; 170 char *name; 171 }; 172 173 /* Function to register/unregister log function. */ 174 int nf_log_register(int pf, struct nf_logger *logger); 175 void nf_log_unregister(struct nf_logger *logger); 176 void nf_log_unregister_pf(int pf); 177 178 /* Calls the registered backend logging function */ 179 void nf_log_packet(int pf, 180 unsigned int hooknum, 181 const struct sk_buff *skb, 182 const struct net_device *in, 183 const struct net_device *out, 184 struct nf_loginfo *li, 185 const char *fmt, ...); 186 187 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb, 188 struct net_device *indev, struct net_device *outdev, 189 int (*okfn)(struct sk_buff *), int thresh); 190 191 /** 192 * nf_hook_thresh - call a netfilter hook 193 * 194 * Returns 1 if the hook has allowed the packet to pass. The function 195 * okfn must be invoked by the caller in this case. Any other return 196 * value indicates the packet has been consumed by the hook. 197 */ 198 static inline int nf_hook_thresh(int pf, unsigned int hook, 199 struct sk_buff **pskb, 200 struct net_device *indev, 201 struct net_device *outdev, 202 int (*okfn)(struct sk_buff *), int thresh, 203 int cond) 204 { 205 if (!cond) 206 return 1; 207 #ifndef CONFIG_NETFILTER_DEBUG 208 if (list_empty(&nf_hooks[pf][hook])) 209 return 1; 210 #endif 211 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh); 212 } 213 214 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 215 struct net_device *indev, struct net_device *outdev, 216 int (*okfn)(struct sk_buff *)) 217 { 218 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1); 219 } 220 221 /* Activate hook; either okfn or kfree_skb called, unless a hook 222 returns NF_STOLEN (in which case, it's up to the hook to deal with 223 the consequences). 224 225 Returns -ERRNO if packet dropped. Zero means queued, stolen or 226 accepted. 227 */ 228 229 /* RR: 230 > I don't want nf_hook to return anything because people might forget 231 > about async and trust the return value to mean "packet was ok". 232 233 AK: 234 Just document it clearly, then you can expect some sense from kernel 235 coders :) 236 */ 237 238 /* This is gross, but inline doesn't cut it for avoiding the function 239 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 240 241 /* HX: It's slightly less gross now. */ 242 243 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 244 ({int __ret; \ 245 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\ 246 __ret = (okfn)(skb); \ 247 __ret;}) 248 249 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 250 ({int __ret; \ 251 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 252 __ret = (okfn)(skb); \ 253 __ret;}) 254 255 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 256 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 257 258 /* Call setsockopt() */ 259 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 260 int len); 261 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 262 int *len); 263 264 int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 265 char __user *opt, int len); 266 int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 267 char __user *opt, int *len); 268 269 /* Packet queuing */ 270 struct nf_queue_handler { 271 int (*outfn)(struct sk_buff *skb, struct nf_info *info, 272 unsigned int queuenum, void *data); 273 void *data; 274 char *name; 275 }; 276 extern int nf_register_queue_handler(int pf, 277 struct nf_queue_handler *qh); 278 extern int nf_unregister_queue_handler(int pf); 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 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 285 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 286 287 /* FIXME: Before cache is ever used, this must be implemented for real. */ 288 extern void nf_invalidate_cache(int pf); 289 290 /* Call this before modifying an existing packet: ensures it is 291 modifiable and linear to the point you care about (writable_len). 292 Returns true or false. */ 293 extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len); 294 295 static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to) 296 { 297 __be32 diff[] = { ~from, to }; 298 299 *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum))); 300 } 301 302 static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to) 303 { 304 nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to); 305 } 306 307 extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, 308 __be32 from, __be32 to, int pseudohdr); 309 310 static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, 311 __be16 from, __be16 to, int pseudohdr) 312 { 313 nf_proto_csum_replace4(sum, skb, (__force __be32)from, 314 (__force __be32)to, pseudohdr); 315 } 316 317 struct nf_afinfo { 318 unsigned short family; 319 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 320 unsigned int dataoff, u_int8_t protocol); 321 void (*saveroute)(const struct sk_buff *skb, 322 struct nf_info *info); 323 int (*reroute)(struct sk_buff **skb, 324 const struct nf_info *info); 325 int route_key_size; 326 }; 327 328 extern struct nf_afinfo *nf_afinfo[]; 329 static inline struct nf_afinfo *nf_get_afinfo(unsigned short family) 330 { 331 return rcu_dereference(nf_afinfo[family]); 332 } 333 334 static inline __sum16 335 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 336 u_int8_t protocol, unsigned short family) 337 { 338 struct nf_afinfo *afinfo; 339 __sum16 csum = 0; 340 341 rcu_read_lock(); 342 afinfo = nf_get_afinfo(family); 343 if (afinfo) 344 csum = afinfo->checksum(skb, hook, dataoff, protocol); 345 rcu_read_unlock(); 346 return csum; 347 } 348 349 extern int nf_register_afinfo(struct nf_afinfo *afinfo); 350 extern void nf_unregister_afinfo(struct nf_afinfo *afinfo); 351 352 #define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info)) 353 354 #include <net/flow.h> 355 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 356 357 static inline void 358 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 359 { 360 #if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED) 361 void (*decodefn)(struct sk_buff *, struct flowi *); 362 363 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) 364 decodefn(skb, fl); 365 #endif 366 } 367 368 #ifdef CONFIG_PROC_FS 369 #include <linux/proc_fs.h> 370 extern struct proc_dir_entry *proc_net_netfilter; 371 #endif 372 373 #else /* !CONFIG_NETFILTER */ 374 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 375 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 376 static inline int nf_hook_thresh(int pf, unsigned int hook, 377 struct sk_buff **pskb, 378 struct net_device *indev, 379 struct net_device *outdev, 380 int (*okfn)(struct sk_buff *), int thresh, 381 int cond) 382 { 383 return okfn(*pskb); 384 } 385 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb, 386 struct net_device *indev, struct net_device *outdev, 387 int (*okfn)(struct sk_buff *)) 388 { 389 return 1; 390 } 391 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 392 struct flowi; 393 static inline void 394 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 395 #endif /*CONFIG_NETFILTER*/ 396 397 #endif /*__KERNEL__*/ 398 #endif /*__LINUX_NETFILTER_H*/ 399