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/if.h> 9 #include <linux/in.h> 10 #include <linux/in6.h> 11 #include <linux/wait.h> 12 #include <linux/list.h> 13 #endif 14 #include <linux/types.h> 15 #include <linux/compiler.h> 16 17 /* Responses from hook functions. */ 18 #define NF_DROP 0 19 #define NF_ACCEPT 1 20 #define NF_STOLEN 2 21 #define NF_QUEUE 3 22 #define NF_REPEAT 4 23 #define NF_STOP 5 24 #define NF_MAX_VERDICT NF_STOP 25 26 /* we overload the higher bits for encoding auxiliary data such as the queue 27 * number. Not nice, but better than additional function arguments. */ 28 #define NF_VERDICT_MASK 0x0000ffff 29 #define NF_VERDICT_BITS 16 30 31 #define NF_VERDICT_QMASK 0xffff0000 32 #define NF_VERDICT_QBITS 16 33 34 #define NF_QUEUE_NR(x) ((((x) << NF_VERDICT_BITS) & NF_VERDICT_QMASK) | NF_QUEUE) 35 36 /* only for userspace compatibility */ 37 #ifndef __KERNEL__ 38 /* Generic cache responses from hook functions. 39 <= 0x2000 is used for protocol-flags. */ 40 #define NFC_UNKNOWN 0x4000 41 #define NFC_ALTERED 0x8000 42 #endif 43 44 enum nf_inet_hooks { 45 NF_INET_PRE_ROUTING, 46 NF_INET_LOCAL_IN, 47 NF_INET_FORWARD, 48 NF_INET_LOCAL_OUT, 49 NF_INET_POST_ROUTING, 50 NF_INET_NUMHOOKS 51 }; 52 53 enum { 54 NFPROTO_UNSPEC = 0, 55 NFPROTO_IPV4 = 2, 56 NFPROTO_ARP = 3, 57 NFPROTO_BRIDGE = 7, 58 NFPROTO_IPV6 = 10, 59 NFPROTO_DECNET = 12, 60 NFPROTO_NUMPROTO, 61 }; 62 63 union nf_inet_addr { 64 __u32 all[4]; 65 __be32 ip; 66 __be32 ip6[4]; 67 struct in_addr in; 68 struct in6_addr in6; 69 }; 70 71 #ifdef __KERNEL__ 72 #ifdef CONFIG_NETFILTER 73 74 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 75 const union nf_inet_addr *a2) 76 { 77 return a1->all[0] == a2->all[0] && 78 a1->all[1] == a2->all[1] && 79 a1->all[2] == a2->all[2] && 80 a1->all[3] == a2->all[3]; 81 } 82 83 extern void netfilter_init(void); 84 85 /* Largest hook number + 1 */ 86 #define NF_MAX_HOOKS 8 87 88 struct sk_buff; 89 90 typedef unsigned int nf_hookfn(unsigned int hooknum, 91 struct sk_buff *skb, 92 const struct net_device *in, 93 const struct net_device *out, 94 int (*okfn)(struct sk_buff *)); 95 96 struct nf_hook_ops { 97 struct list_head list; 98 99 /* User fills in from here down. */ 100 nf_hookfn *hook; 101 struct module *owner; 102 u_int8_t pf; 103 unsigned int hooknum; 104 /* Hooks are ordered in ascending priority. */ 105 int priority; 106 }; 107 108 struct nf_sockopt_ops { 109 struct list_head list; 110 111 u_int8_t pf; 112 113 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 114 int set_optmin; 115 int set_optmax; 116 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 117 int (*compat_set)(struct sock *sk, int optval, 118 void __user *user, unsigned int len); 119 120 int get_optmin; 121 int get_optmax; 122 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 123 int (*compat_get)(struct sock *sk, int optval, 124 void __user *user, int *len); 125 126 /* Use the module struct to lock set/get code in place */ 127 struct module *owner; 128 }; 129 130 /* Function to register/unregister hook points. */ 131 int nf_register_hook(struct nf_hook_ops *reg); 132 void nf_unregister_hook(struct nf_hook_ops *reg); 133 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 134 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 135 136 /* Functions to register get/setsockopt ranges (non-inclusive). You 137 need to check permissions yourself! */ 138 int nf_register_sockopt(struct nf_sockopt_ops *reg); 139 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 140 141 #ifdef CONFIG_SYSCTL 142 /* Sysctl registration */ 143 extern struct ctl_path nf_net_netfilter_sysctl_path[]; 144 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; 145 #endif /* CONFIG_SYSCTL */ 146 147 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 148 149 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 150 struct net_device *indev, struct net_device *outdev, 151 int (*okfn)(struct sk_buff *), int thresh); 152 153 /** 154 * nf_hook_thresh - call a netfilter hook 155 * 156 * Returns 1 if the hook has allowed the packet to pass. The function 157 * okfn must be invoked by the caller in this case. Any other return 158 * value indicates the packet has been consumed by the hook. 159 */ 160 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 161 struct sk_buff *skb, 162 struct net_device *indev, 163 struct net_device *outdev, 164 int (*okfn)(struct sk_buff *), int thresh, 165 int cond) 166 { 167 if (!cond) 168 return 1; 169 #ifndef CONFIG_NETFILTER_DEBUG 170 if (list_empty(&nf_hooks[pf][hook])) 171 return 1; 172 #endif 173 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 174 } 175 176 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 177 struct net_device *indev, struct net_device *outdev, 178 int (*okfn)(struct sk_buff *)) 179 { 180 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1); 181 } 182 183 /* Activate hook; either okfn or kfree_skb called, unless a hook 184 returns NF_STOLEN (in which case, it's up to the hook to deal with 185 the consequences). 186 187 Returns -ERRNO if packet dropped. Zero means queued, stolen or 188 accepted. 189 */ 190 191 /* RR: 192 > I don't want nf_hook to return anything because people might forget 193 > about async and trust the return value to mean "packet was ok". 194 195 AK: 196 Just document it clearly, then you can expect some sense from kernel 197 coders :) 198 */ 199 200 /* This is gross, but inline doesn't cut it for avoiding the function 201 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 202 203 /* HX: It's slightly less gross now. */ 204 205 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 206 ({int __ret; \ 207 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\ 208 __ret = (okfn)(skb); \ 209 __ret;}) 210 211 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 212 ({int __ret; \ 213 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 214 __ret = (okfn)(skb); \ 215 __ret;}) 216 217 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 218 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 219 220 /* Call setsockopt() */ 221 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 222 unsigned int len); 223 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 224 int *len); 225 226 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 227 char __user *opt, unsigned int len); 228 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 229 char __user *opt, int *len); 230 231 /* Call this before modifying an existing packet: ensures it is 232 modifiable and linear to the point you care about (writable_len). 233 Returns true or false. */ 234 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 235 236 struct flowi; 237 struct nf_queue_entry; 238 239 struct nf_afinfo { 240 unsigned short family; 241 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 242 unsigned int dataoff, u_int8_t protocol); 243 __sum16 (*checksum_partial)(struct sk_buff *skb, 244 unsigned int hook, 245 unsigned int dataoff, 246 unsigned int len, 247 u_int8_t protocol); 248 int (*route)(struct dst_entry **dst, struct flowi *fl); 249 void (*saveroute)(const struct sk_buff *skb, 250 struct nf_queue_entry *entry); 251 int (*reroute)(struct sk_buff *skb, 252 const struct nf_queue_entry *entry); 253 int route_key_size; 254 }; 255 256 extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO]; 257 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 258 { 259 return rcu_dereference(nf_afinfo[family]); 260 } 261 262 static inline __sum16 263 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 264 u_int8_t protocol, unsigned short family) 265 { 266 const struct nf_afinfo *afinfo; 267 __sum16 csum = 0; 268 269 rcu_read_lock(); 270 afinfo = nf_get_afinfo(family); 271 if (afinfo) 272 csum = afinfo->checksum(skb, hook, dataoff, protocol); 273 rcu_read_unlock(); 274 return csum; 275 } 276 277 static inline __sum16 278 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 279 unsigned int dataoff, unsigned int len, 280 u_int8_t protocol, unsigned short family) 281 { 282 const struct nf_afinfo *afinfo; 283 __sum16 csum = 0; 284 285 rcu_read_lock(); 286 afinfo = nf_get_afinfo(family); 287 if (afinfo) 288 csum = afinfo->checksum_partial(skb, hook, dataoff, len, 289 protocol); 290 rcu_read_unlock(); 291 return csum; 292 } 293 294 extern int nf_register_afinfo(const struct nf_afinfo *afinfo); 295 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 296 297 #include <net/flow.h> 298 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 299 300 static inline void 301 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 302 { 303 #ifdef CONFIG_NF_NAT_NEEDED 304 void (*decodefn)(struct sk_buff *, struct flowi *); 305 306 if (family == AF_INET) { 307 rcu_read_lock(); 308 decodefn = rcu_dereference(ip_nat_decode_session); 309 if (decodefn) 310 decodefn(skb, fl); 311 rcu_read_unlock(); 312 } 313 #endif 314 } 315 316 #ifdef CONFIG_PROC_FS 317 #include <linux/proc_fs.h> 318 extern struct proc_dir_entry *proc_net_netfilter; 319 #endif 320 321 #else /* !CONFIG_NETFILTER */ 322 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 323 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 324 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 325 struct sk_buff *skb, 326 struct net_device *indev, 327 struct net_device *outdev, 328 int (*okfn)(struct sk_buff *), int thresh, 329 int cond) 330 { 331 return okfn(skb); 332 } 333 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 334 struct net_device *indev, struct net_device *outdev, 335 int (*okfn)(struct sk_buff *)) 336 { 337 return 1; 338 } 339 struct flowi; 340 static inline void 341 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 342 { 343 } 344 #endif /*CONFIG_NETFILTER*/ 345 346 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 347 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 348 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 349 extern void (*nf_ct_destroy)(struct nf_conntrack *); 350 #else 351 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 352 #endif 353 354 #endif /*__KERNEL__*/ 355 #endif /*__LINUX_NETFILTER_H*/ 356