1 #ifndef __LINUX_NETFILTER_H 2 #define __LINUX_NETFILTER_H 3 4 #ifdef __KERNEL__ 5 #include <linux/init.h> 6 #include <linux/skbuff.h> 7 #include <linux/net.h> 8 #include <linux/netdevice.h> 9 #include <linux/if.h> 10 #include <linux/in.h> 11 #include <linux/in6.h> 12 #include <linux/wait.h> 13 #include <linux/list.h> 14 #include <net/net_namespace.h> 15 #endif 16 #include <linux/types.h> 17 #include <linux/compiler.h> 18 19 /* Responses from hook functions. */ 20 #define NF_DROP 0 21 #define NF_ACCEPT 1 22 #define NF_STOLEN 2 23 #define NF_QUEUE 3 24 #define NF_REPEAT 4 25 #define NF_STOP 5 26 #define NF_MAX_VERDICT NF_STOP 27 28 /* we overload the higher bits for encoding auxiliary data such as the queue 29 * number. Not nice, but better than additional function arguments. */ 30 #define NF_VERDICT_MASK 0x0000ffff 31 #define NF_VERDICT_BITS 16 32 33 #define NF_VERDICT_QMASK 0xffff0000 34 #define NF_VERDICT_QBITS 16 35 36 #define NF_QUEUE_NR(x) ((((x) << NF_VERDICT_BITS) & NF_VERDICT_QMASK) | NF_QUEUE) 37 38 /* only for userspace compatibility */ 39 #ifndef __KERNEL__ 40 /* Generic cache responses from hook functions. 41 <= 0x2000 is used for protocol-flags. */ 42 #define NFC_UNKNOWN 0x4000 43 #define NFC_ALTERED 0x8000 44 #endif 45 46 enum nf_inet_hooks { 47 NF_INET_PRE_ROUTING, 48 NF_INET_LOCAL_IN, 49 NF_INET_FORWARD, 50 NF_INET_LOCAL_OUT, 51 NF_INET_POST_ROUTING, 52 NF_INET_NUMHOOKS 53 }; 54 55 union nf_inet_addr { 56 __u32 all[4]; 57 __be32 ip; 58 __be32 ip6[4]; 59 struct in_addr in; 60 struct in6_addr in6; 61 }; 62 63 #ifdef __KERNEL__ 64 #ifdef CONFIG_NETFILTER 65 66 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 67 const union nf_inet_addr *a2) 68 { 69 return a1->all[0] == a2->all[0] && 70 a1->all[1] == a2->all[1] && 71 a1->all[2] == a2->all[2] && 72 a1->all[3] == a2->all[3]; 73 } 74 75 extern void netfilter_init(void); 76 77 /* Largest hook number + 1 */ 78 #define NF_MAX_HOOKS 8 79 80 struct sk_buff; 81 82 typedef unsigned int nf_hookfn(unsigned int hooknum, 83 struct sk_buff *skb, 84 const struct net_device *in, 85 const struct net_device *out, 86 int (*okfn)(struct sk_buff *)); 87 88 struct nf_hook_ops 89 { 90 struct list_head list; 91 92 /* User fills in from here down. */ 93 nf_hookfn *hook; 94 struct module *owner; 95 int pf; 96 int hooknum; 97 /* Hooks are ordered in ascending priority. */ 98 int priority; 99 }; 100 101 struct nf_sockopt_ops 102 { 103 struct list_head list; 104 105 int pf; 106 107 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 108 int set_optmin; 109 int set_optmax; 110 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 111 int (*compat_set)(struct sock *sk, int optval, 112 void __user *user, unsigned int len); 113 114 int get_optmin; 115 int get_optmax; 116 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 117 int (*compat_get)(struct sock *sk, int optval, 118 void __user *user, int *len); 119 120 /* Use the module struct to lock set/get code in place */ 121 struct module *owner; 122 }; 123 124 /* Function to register/unregister hook points. */ 125 int nf_register_hook(struct nf_hook_ops *reg); 126 void nf_unregister_hook(struct nf_hook_ops *reg); 127 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 128 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 129 130 /* Functions to register get/setsockopt ranges (non-inclusive). You 131 need to check permissions yourself! */ 132 int nf_register_sockopt(struct nf_sockopt_ops *reg); 133 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 134 135 #ifdef CONFIG_SYSCTL 136 /* Sysctl registration */ 137 extern struct ctl_path nf_net_netfilter_sysctl_path[]; 138 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; 139 #endif /* CONFIG_SYSCTL */ 140 141 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; 142 143 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb, 144 struct net_device *indev, struct net_device *outdev, 145 int (*okfn)(struct sk_buff *), int thresh); 146 147 /** 148 * nf_hook_thresh - call a netfilter hook 149 * 150 * Returns 1 if the hook has allowed the packet to pass. The function 151 * okfn must be invoked by the caller in this case. Any other return 152 * value indicates the packet has been consumed by the hook. 153 */ 154 static inline int nf_hook_thresh(int pf, unsigned int hook, 155 struct sk_buff *skb, 156 struct net_device *indev, 157 struct net_device *outdev, 158 int (*okfn)(struct sk_buff *), int thresh, 159 int cond) 160 { 161 if (!cond) 162 return 1; 163 #ifndef CONFIG_NETFILTER_DEBUG 164 if (list_empty(&nf_hooks[pf][hook])) 165 return 1; 166 #endif 167 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 168 } 169 170 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 171 struct net_device *indev, struct net_device *outdev, 172 int (*okfn)(struct sk_buff *)) 173 { 174 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1); 175 } 176 177 /* Activate hook; either okfn or kfree_skb called, unless a hook 178 returns NF_STOLEN (in which case, it's up to the hook to deal with 179 the consequences). 180 181 Returns -ERRNO if packet dropped. Zero means queued, stolen or 182 accepted. 183 */ 184 185 /* RR: 186 > I don't want nf_hook to return anything because people might forget 187 > about async and trust the return value to mean "packet was ok". 188 189 AK: 190 Just document it clearly, then you can expect some sense from kernel 191 coders :) 192 */ 193 194 /* This is gross, but inline doesn't cut it for avoiding the function 195 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 196 197 /* HX: It's slightly less gross now. */ 198 199 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 200 ({int __ret; \ 201 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\ 202 __ret = (okfn)(skb); \ 203 __ret;}) 204 205 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 206 ({int __ret; \ 207 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 208 __ret = (okfn)(skb); \ 209 __ret;}) 210 211 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 212 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 213 214 /* Call setsockopt() */ 215 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt, 216 int len); 217 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, 218 int *len); 219 220 int compat_nf_setsockopt(struct sock *sk, int pf, int optval, 221 char __user *opt, int len); 222 int compat_nf_getsockopt(struct sock *sk, int pf, int optval, 223 char __user *opt, int *len); 224 225 /* Call this before modifying an existing packet: ensures it is 226 modifiable and linear to the point you care about (writable_len). 227 Returns true or false. */ 228 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 229 230 struct flowi; 231 struct nf_queue_entry; 232 233 struct nf_afinfo { 234 unsigned short family; 235 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 236 unsigned int dataoff, u_int8_t protocol); 237 __sum16 (*checksum_partial)(struct sk_buff *skb, 238 unsigned int hook, 239 unsigned int dataoff, 240 unsigned int len, 241 u_int8_t protocol); 242 int (*route)(struct dst_entry **dst, struct flowi *fl); 243 void (*saveroute)(const struct sk_buff *skb, 244 struct nf_queue_entry *entry); 245 int (*reroute)(struct sk_buff *skb, 246 const struct nf_queue_entry *entry); 247 int route_key_size; 248 }; 249 250 extern const struct nf_afinfo *nf_afinfo[NPROTO]; 251 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 252 { 253 return rcu_dereference(nf_afinfo[family]); 254 } 255 256 static inline __sum16 257 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 258 u_int8_t protocol, unsigned short family) 259 { 260 const struct nf_afinfo *afinfo; 261 __sum16 csum = 0; 262 263 rcu_read_lock(); 264 afinfo = nf_get_afinfo(family); 265 if (afinfo) 266 csum = afinfo->checksum(skb, hook, dataoff, protocol); 267 rcu_read_unlock(); 268 return csum; 269 } 270 271 static inline __sum16 272 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 273 unsigned int dataoff, unsigned int len, 274 u_int8_t protocol, unsigned short family) 275 { 276 const struct nf_afinfo *afinfo; 277 __sum16 csum = 0; 278 279 rcu_read_lock(); 280 afinfo = nf_get_afinfo(family); 281 if (afinfo) 282 csum = afinfo->checksum_partial(skb, hook, dataoff, len, 283 protocol); 284 rcu_read_unlock(); 285 return csum; 286 } 287 288 extern int nf_register_afinfo(const struct nf_afinfo *afinfo); 289 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 290 291 #include <net/flow.h> 292 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 293 294 static inline void 295 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) 296 { 297 #ifdef CONFIG_NF_NAT_NEEDED 298 void (*decodefn)(struct sk_buff *, struct flowi *); 299 300 if (family == AF_INET) { 301 rcu_read_lock(); 302 decodefn = rcu_dereference(ip_nat_decode_session); 303 if (decodefn) 304 decodefn(skb, fl); 305 rcu_read_unlock(); 306 } 307 #endif 308 } 309 310 #ifdef CONFIG_PROC_FS 311 #include <linux/proc_fs.h> 312 extern struct proc_dir_entry *proc_net_netfilter; 313 #endif 314 315 #else /* !CONFIG_NETFILTER */ 316 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 317 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 318 static inline int nf_hook_thresh(int pf, unsigned int hook, 319 struct sk_buff *skb, 320 struct net_device *indev, 321 struct net_device *outdev, 322 int (*okfn)(struct sk_buff *), int thresh, 323 int cond) 324 { 325 return okfn(skb); 326 } 327 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff *skb, 328 struct net_device *indev, struct net_device *outdev, 329 int (*okfn)(struct sk_buff *)) 330 { 331 return 1; 332 } 333 struct flowi; 334 static inline void 335 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} 336 #endif /*CONFIG_NETFILTER*/ 337 338 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 339 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 340 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 341 extern void (*nf_ct_destroy)(struct nf_conntrack *); 342 #else 343 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 344 #endif 345 346 static inline struct net *nf_pre_routing_net(const struct net_device *in, 347 const struct net_device *out) 348 { 349 #ifdef CONFIG_NET_NS 350 return in->nd_net; 351 #else 352 return &init_net; 353 #endif 354 } 355 356 static inline struct net *nf_local_in_net(const struct net_device *in, 357 const struct net_device *out) 358 { 359 #ifdef CONFIG_NET_NS 360 return in->nd_net; 361 #else 362 return &init_net; 363 #endif 364 } 365 366 static inline struct net *nf_forward_net(const struct net_device *in, 367 const struct net_device *out) 368 { 369 #ifdef CONFIG_NET_NS 370 BUG_ON(in->nd_net != out->nd_net); 371 return in->nd_net; 372 #else 373 return &init_net; 374 #endif 375 } 376 377 static inline struct net *nf_local_out_net(const struct net_device *in, 378 const struct net_device *out) 379 { 380 #ifdef CONFIG_NET_NS 381 return out->nd_net; 382 #else 383 return &init_net; 384 #endif 385 } 386 387 static inline struct net *nf_post_routing_net(const struct net_device *in, 388 const struct net_device *out) 389 { 390 #ifdef CONFIG_NET_NS 391 return out->nd_net; 392 #else 393 return &init_net; 394 #endif 395 } 396 397 #endif /*__KERNEL__*/ 398 #endif /*__LINUX_NETFILTER_H*/ 399