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 { 98 struct list_head list; 99 100 /* User fills in from here down. */ 101 nf_hookfn *hook; 102 struct module *owner; 103 u_int8_t pf; 104 unsigned int hooknum; 105 /* Hooks are ordered in ascending priority. */ 106 int priority; 107 }; 108 109 struct nf_sockopt_ops 110 { 111 struct list_head list; 112 113 u_int8_t pf; 114 115 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 116 int set_optmin; 117 int set_optmax; 118 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 119 int (*compat_set)(struct sock *sk, int optval, 120 void __user *user, unsigned int len); 121 122 int get_optmin; 123 int get_optmax; 124 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 125 int (*compat_get)(struct sock *sk, int optval, 126 void __user *user, int *len); 127 128 /* Use the module struct to lock set/get code in place */ 129 struct module *owner; 130 }; 131 132 /* Function to register/unregister hook points. */ 133 int nf_register_hook(struct nf_hook_ops *reg); 134 void nf_unregister_hook(struct nf_hook_ops *reg); 135 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 136 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 137 138 /* Functions to register get/setsockopt ranges (non-inclusive). You 139 need to check permissions yourself! */ 140 int nf_register_sockopt(struct nf_sockopt_ops *reg); 141 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 142 143 #ifdef CONFIG_SYSCTL 144 /* Sysctl registration */ 145 extern struct ctl_path nf_net_netfilter_sysctl_path[]; 146 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; 147 #endif /* CONFIG_SYSCTL */ 148 149 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 150 151 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 152 struct net_device *indev, struct net_device *outdev, 153 int (*okfn)(struct sk_buff *), int thresh); 154 155 /** 156 * nf_hook_thresh - call a netfilter hook 157 * 158 * Returns 1 if the hook has allowed the packet to pass. The function 159 * okfn must be invoked by the caller in this case. Any other return 160 * value indicates the packet has been consumed by the hook. 161 */ 162 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 163 struct sk_buff *skb, 164 struct net_device *indev, 165 struct net_device *outdev, 166 int (*okfn)(struct sk_buff *), int thresh, 167 int cond) 168 { 169 if (!cond) 170 return 1; 171 #ifndef CONFIG_NETFILTER_DEBUG 172 if (list_empty(&nf_hooks[pf][hook])) 173 return 1; 174 #endif 175 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 176 } 177 178 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 179 struct net_device *indev, struct net_device *outdev, 180 int (*okfn)(struct sk_buff *)) 181 { 182 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN, 1); 183 } 184 185 /* Activate hook; either okfn or kfree_skb called, unless a hook 186 returns NF_STOLEN (in which case, it's up to the hook to deal with 187 the consequences). 188 189 Returns -ERRNO if packet dropped. Zero means queued, stolen or 190 accepted. 191 */ 192 193 /* RR: 194 > I don't want nf_hook to return anything because people might forget 195 > about async and trust the return value to mean "packet was ok". 196 197 AK: 198 Just document it clearly, then you can expect some sense from kernel 199 coders :) 200 */ 201 202 /* This is gross, but inline doesn't cut it for avoiding the function 203 call in fast path: gcc doesn't inline (needs value tracking?). --RR */ 204 205 /* HX: It's slightly less gross now. */ 206 207 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \ 208 ({int __ret; \ 209 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, thresh, 1)) == 1)\ 210 __ret = (okfn)(skb); \ 211 __ret;}) 212 213 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \ 214 ({int __ret; \ 215 if ((__ret=nf_hook_thresh(pf, hook, (skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\ 216 __ret = (okfn)(skb); \ 217 __ret;}) 218 219 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \ 220 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN) 221 222 /* Call setsockopt() */ 223 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 224 int len); 225 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 226 int *len); 227 228 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 229 char __user *opt, int len); 230 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 231 char __user *opt, int *len); 232 233 /* Call this before modifying an existing packet: ensures it is 234 modifiable and linear to the point you care about (writable_len). 235 Returns true or false. */ 236 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 237 238 struct flowi; 239 struct nf_queue_entry; 240 241 struct nf_afinfo { 242 unsigned short family; 243 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 244 unsigned int dataoff, u_int8_t protocol); 245 __sum16 (*checksum_partial)(struct sk_buff *skb, 246 unsigned int hook, 247 unsigned int dataoff, 248 unsigned int len, 249 u_int8_t protocol); 250 int (*route)(struct dst_entry **dst, struct flowi *fl); 251 void (*saveroute)(const struct sk_buff *skb, 252 struct nf_queue_entry *entry); 253 int (*reroute)(struct sk_buff *skb, 254 const struct nf_queue_entry *entry); 255 int route_key_size; 256 }; 257 258 extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO]; 259 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 260 { 261 return rcu_dereference(nf_afinfo[family]); 262 } 263 264 static inline __sum16 265 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 266 u_int8_t protocol, unsigned short family) 267 { 268 const struct nf_afinfo *afinfo; 269 __sum16 csum = 0; 270 271 rcu_read_lock(); 272 afinfo = nf_get_afinfo(family); 273 if (afinfo) 274 csum = afinfo->checksum(skb, hook, dataoff, protocol); 275 rcu_read_unlock(); 276 return csum; 277 } 278 279 static inline __sum16 280 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 281 unsigned int dataoff, unsigned int len, 282 u_int8_t protocol, unsigned short family) 283 { 284 const struct nf_afinfo *afinfo; 285 __sum16 csum = 0; 286 287 rcu_read_lock(); 288 afinfo = nf_get_afinfo(family); 289 if (afinfo) 290 csum = afinfo->checksum_partial(skb, hook, dataoff, len, 291 protocol); 292 rcu_read_unlock(); 293 return csum; 294 } 295 296 extern int nf_register_afinfo(const struct nf_afinfo *afinfo); 297 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 298 299 #include <net/flow.h> 300 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 301 302 static inline void 303 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 304 { 305 #ifdef CONFIG_NF_NAT_NEEDED 306 void (*decodefn)(struct sk_buff *, struct flowi *); 307 308 if (family == AF_INET) { 309 rcu_read_lock(); 310 decodefn = rcu_dereference(ip_nat_decode_session); 311 if (decodefn) 312 decodefn(skb, fl); 313 rcu_read_unlock(); 314 } 315 #endif 316 } 317 318 #ifdef CONFIG_PROC_FS 319 #include <linux/proc_fs.h> 320 extern struct proc_dir_entry *proc_net_netfilter; 321 #endif 322 323 #else /* !CONFIG_NETFILTER */ 324 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 325 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 326 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 327 struct sk_buff *skb, 328 struct net_device *indev, 329 struct net_device *outdev, 330 int (*okfn)(struct sk_buff *), int thresh, 331 int cond) 332 { 333 return okfn(skb); 334 } 335 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 336 struct net_device *indev, struct net_device *outdev, 337 int (*okfn)(struct sk_buff *)) 338 { 339 return 1; 340 } 341 struct flowi; 342 static inline void 343 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 344 { 345 } 346 #endif /*CONFIG_NETFILTER*/ 347 348 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 349 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 350 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 351 extern void (*nf_ct_destroy)(struct nf_conntrack *); 352 #else 353 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 354 #endif 355 356 #endif /*__KERNEL__*/ 357 #endif /*__LINUX_NETFILTER_H*/ 358