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 #define NF_DROP_ERR(x) (((-x) << NF_VERDICT_BITS) | NF_DROP) 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 enum { 56 NFPROTO_UNSPEC = 0, 57 NFPROTO_IPV4 = 2, 58 NFPROTO_ARP = 3, 59 NFPROTO_BRIDGE = 7, 60 NFPROTO_IPV6 = 10, 61 NFPROTO_DECNET = 12, 62 NFPROTO_NUMPROTO, 63 }; 64 65 union nf_inet_addr { 66 __u32 all[4]; 67 __be32 ip; 68 __be32 ip6[4]; 69 struct in_addr in; 70 struct in6_addr in6; 71 }; 72 73 #ifdef __KERNEL__ 74 #ifdef CONFIG_NETFILTER 75 76 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 77 const union nf_inet_addr *a2) 78 { 79 return a1->all[0] == a2->all[0] && 80 a1->all[1] == a2->all[1] && 81 a1->all[2] == a2->all[2] && 82 a1->all[3] == a2->all[3]; 83 } 84 85 extern void netfilter_init(void); 86 87 /* Largest hook number + 1 */ 88 #define NF_MAX_HOOKS 8 89 90 struct sk_buff; 91 92 typedef unsigned int nf_hookfn(unsigned int hooknum, 93 struct sk_buff *skb, 94 const struct net_device *in, 95 const struct net_device *out, 96 int (*okfn)(struct sk_buff *)); 97 98 struct nf_hook_ops { 99 struct list_head list; 100 101 /* User fills in from here down. */ 102 nf_hookfn *hook; 103 struct module *owner; 104 u_int8_t pf; 105 unsigned int hooknum; 106 /* Hooks are ordered in ascending priority. */ 107 int priority; 108 }; 109 110 struct nf_sockopt_ops { 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 #ifdef CONFIG_COMPAT 120 int (*compat_set)(struct sock *sk, int optval, 121 void __user *user, unsigned int len); 122 #endif 123 int get_optmin; 124 int get_optmax; 125 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 126 #ifdef CONFIG_COMPAT 127 int (*compat_get)(struct sock *sk, int optval, 128 void __user *user, int *len); 129 #endif 130 /* Use the module struct to lock set/get code in place */ 131 struct module *owner; 132 }; 133 134 /* Function to register/unregister hook points. */ 135 int nf_register_hook(struct nf_hook_ops *reg); 136 void nf_unregister_hook(struct nf_hook_ops *reg); 137 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 138 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 139 140 /* Functions to register get/setsockopt ranges (non-inclusive). You 141 need to check permissions yourself! */ 142 int nf_register_sockopt(struct nf_sockopt_ops *reg); 143 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 144 145 #ifdef CONFIG_SYSCTL 146 /* Sysctl registration */ 147 extern struct ctl_path nf_net_netfilter_sysctl_path[]; 148 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; 149 #endif /* CONFIG_SYSCTL */ 150 151 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 152 153 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 154 struct net_device *indev, struct net_device *outdev, 155 int (*okfn)(struct sk_buff *), int thresh); 156 157 /** 158 * nf_hook_thresh - call a netfilter hook 159 * 160 * Returns 1 if the hook has allowed the packet to pass. The function 161 * okfn must be invoked by the caller in this case. Any other return 162 * value indicates the packet has been consumed by the hook. 163 */ 164 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 165 struct sk_buff *skb, 166 struct net_device *indev, 167 struct net_device *outdev, 168 int (*okfn)(struct sk_buff *), int thresh) 169 { 170 #ifndef CONFIG_NETFILTER_DEBUG 171 if (list_empty(&nf_hooks[pf][hook])) 172 return 1; 173 #endif 174 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 175 } 176 177 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 178 struct net_device *indev, struct net_device *outdev, 179 int (*okfn)(struct sk_buff *)) 180 { 181 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN); 182 } 183 184 /* Activate hook; either okfn or kfree_skb called, unless a hook 185 returns NF_STOLEN (in which case, it's up to the hook to deal with 186 the consequences). 187 188 Returns -ERRNO if packet dropped. Zero means queued, stolen or 189 accepted. 190 */ 191 192 /* RR: 193 > I don't want nf_hook to return anything because people might forget 194 > about async and trust the return value to mean "packet was ok". 195 196 AK: 197 Just document it clearly, then you can expect some sense from kernel 198 coders :) 199 */ 200 201 static inline int 202 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb, 203 struct net_device *in, struct net_device *out, 204 int (*okfn)(struct sk_buff *), int thresh) 205 { 206 int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh); 207 if (ret == 1) 208 ret = okfn(skb); 209 return ret; 210 } 211 212 static inline int 213 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb, 214 struct net_device *in, struct net_device *out, 215 int (*okfn)(struct sk_buff *), bool cond) 216 { 217 int ret; 218 219 if (!cond || 220 ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1)) 221 ret = okfn(skb); 222 return ret; 223 } 224 225 static inline int 226 NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb, 227 struct net_device *in, struct net_device *out, 228 int (*okfn)(struct sk_buff *)) 229 { 230 return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN); 231 } 232 233 /* Call setsockopt() */ 234 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 235 unsigned int len); 236 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 237 int *len); 238 #ifdef CONFIG_COMPAT 239 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 240 char __user *opt, unsigned int len); 241 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 242 char __user *opt, int *len); 243 #endif 244 245 /* Call this before modifying an existing packet: ensures it is 246 modifiable and linear to the point you care about (writable_len). 247 Returns true or false. */ 248 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 249 250 struct flowi; 251 struct nf_queue_entry; 252 253 struct nf_afinfo { 254 unsigned short family; 255 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 256 unsigned int dataoff, u_int8_t protocol); 257 __sum16 (*checksum_partial)(struct sk_buff *skb, 258 unsigned int hook, 259 unsigned int dataoff, 260 unsigned int len, 261 u_int8_t protocol); 262 int (*route)(struct dst_entry **dst, struct flowi *fl); 263 void (*saveroute)(const struct sk_buff *skb, 264 struct nf_queue_entry *entry); 265 int (*reroute)(struct sk_buff *skb, 266 const struct nf_queue_entry *entry); 267 int route_key_size; 268 }; 269 270 extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO]; 271 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 272 { 273 return rcu_dereference(nf_afinfo[family]); 274 } 275 276 static inline __sum16 277 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 278 u_int8_t protocol, unsigned short family) 279 { 280 const struct nf_afinfo *afinfo; 281 __sum16 csum = 0; 282 283 rcu_read_lock(); 284 afinfo = nf_get_afinfo(family); 285 if (afinfo) 286 csum = afinfo->checksum(skb, hook, dataoff, protocol); 287 rcu_read_unlock(); 288 return csum; 289 } 290 291 static inline __sum16 292 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 293 unsigned int dataoff, unsigned int len, 294 u_int8_t protocol, unsigned short family) 295 { 296 const struct nf_afinfo *afinfo; 297 __sum16 csum = 0; 298 299 rcu_read_lock(); 300 afinfo = nf_get_afinfo(family); 301 if (afinfo) 302 csum = afinfo->checksum_partial(skb, hook, dataoff, len, 303 protocol); 304 rcu_read_unlock(); 305 return csum; 306 } 307 308 extern int nf_register_afinfo(const struct nf_afinfo *afinfo); 309 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 310 311 #include <net/flow.h> 312 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 313 314 static inline void 315 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 316 { 317 #ifdef CONFIG_NF_NAT_NEEDED 318 void (*decodefn)(struct sk_buff *, struct flowi *); 319 320 if (family == AF_INET) { 321 rcu_read_lock(); 322 decodefn = rcu_dereference(ip_nat_decode_session); 323 if (decodefn) 324 decodefn(skb, fl); 325 rcu_read_unlock(); 326 } 327 #endif 328 } 329 330 #ifdef CONFIG_PROC_FS 331 #include <linux/proc_fs.h> 332 extern struct proc_dir_entry *proc_net_netfilter; 333 #endif 334 335 #else /* !CONFIG_NETFILTER */ 336 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 337 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 338 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 339 struct sk_buff *skb, 340 struct net_device *indev, 341 struct net_device *outdev, 342 int (*okfn)(struct sk_buff *), int thresh) 343 { 344 return okfn(skb); 345 } 346 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 347 struct net_device *indev, struct net_device *outdev, 348 int (*okfn)(struct sk_buff *)) 349 { 350 return 1; 351 } 352 struct flowi; 353 static inline void 354 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 355 { 356 } 357 #endif /*CONFIG_NETFILTER*/ 358 359 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 360 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 361 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 362 extern void (*nf_ct_destroy)(struct nf_conntrack *); 363 #else 364 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 365 #endif 366 367 #endif /*__KERNEL__*/ 368 #endif /*__LINUX_NETFILTER_H*/ 369