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 #ifdef CONFIG_COMPAT 118 int (*compat_set)(struct sock *sk, int optval, 119 void __user *user, unsigned int len); 120 #endif 121 int get_optmin; 122 int get_optmax; 123 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 124 #ifdef CONFIG_COMPAT 125 int (*compat_get)(struct sock *sk, int optval, 126 void __user *user, int *len); 127 #endif 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 { 168 #ifndef CONFIG_NETFILTER_DEBUG 169 if (list_empty(&nf_hooks[pf][hook])) 170 return 1; 171 #endif 172 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); 173 } 174 175 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 176 struct net_device *indev, struct net_device *outdev, 177 int (*okfn)(struct sk_buff *)) 178 { 179 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN); 180 } 181 182 /* Activate hook; either okfn or kfree_skb called, unless a hook 183 returns NF_STOLEN (in which case, it's up to the hook to deal with 184 the consequences). 185 186 Returns -ERRNO if packet dropped. Zero means queued, stolen or 187 accepted. 188 */ 189 190 /* RR: 191 > I don't want nf_hook to return anything because people might forget 192 > about async and trust the return value to mean "packet was ok". 193 194 AK: 195 Just document it clearly, then you can expect some sense from kernel 196 coders :) 197 */ 198 199 static inline int 200 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb, 201 struct net_device *in, struct net_device *out, 202 int (*okfn)(struct sk_buff *), int thresh) 203 { 204 int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh); 205 if (ret == 1) 206 ret = okfn(skb); 207 return ret; 208 } 209 210 static inline int 211 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb, 212 struct net_device *in, struct net_device *out, 213 int (*okfn)(struct sk_buff *), bool cond) 214 { 215 int ret; 216 217 if (!cond || 218 ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1)) 219 ret = okfn(skb); 220 return ret; 221 } 222 223 static inline int 224 NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb, 225 struct net_device *in, struct net_device *out, 226 int (*okfn)(struct sk_buff *)) 227 { 228 return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN); 229 } 230 231 /* Call setsockopt() */ 232 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 233 unsigned int len); 234 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 235 int *len); 236 #ifdef CONFIG_COMPAT 237 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 238 char __user *opt, unsigned int len); 239 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 240 char __user *opt, int *len); 241 #endif 242 243 /* Call this before modifying an existing packet: ensures it is 244 modifiable and linear to the point you care about (writable_len). 245 Returns true or false. */ 246 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 247 248 struct flowi; 249 struct nf_queue_entry; 250 251 struct nf_afinfo { 252 unsigned short family; 253 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 254 unsigned int dataoff, u_int8_t protocol); 255 __sum16 (*checksum_partial)(struct sk_buff *skb, 256 unsigned int hook, 257 unsigned int dataoff, 258 unsigned int len, 259 u_int8_t protocol); 260 int (*route)(struct dst_entry **dst, struct flowi *fl); 261 void (*saveroute)(const struct sk_buff *skb, 262 struct nf_queue_entry *entry); 263 int (*reroute)(struct sk_buff *skb, 264 const struct nf_queue_entry *entry); 265 int route_key_size; 266 }; 267 268 extern const struct nf_afinfo *nf_afinfo[NFPROTO_NUMPROTO]; 269 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 270 { 271 return rcu_dereference(nf_afinfo[family]); 272 } 273 274 static inline __sum16 275 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 276 u_int8_t protocol, unsigned short family) 277 { 278 const struct nf_afinfo *afinfo; 279 __sum16 csum = 0; 280 281 rcu_read_lock(); 282 afinfo = nf_get_afinfo(family); 283 if (afinfo) 284 csum = afinfo->checksum(skb, hook, dataoff, protocol); 285 rcu_read_unlock(); 286 return csum; 287 } 288 289 static inline __sum16 290 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 291 unsigned int dataoff, unsigned int len, 292 u_int8_t protocol, unsigned short family) 293 { 294 const struct nf_afinfo *afinfo; 295 __sum16 csum = 0; 296 297 rcu_read_lock(); 298 afinfo = nf_get_afinfo(family); 299 if (afinfo) 300 csum = afinfo->checksum_partial(skb, hook, dataoff, len, 301 protocol); 302 rcu_read_unlock(); 303 return csum; 304 } 305 306 extern int nf_register_afinfo(const struct nf_afinfo *afinfo); 307 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 308 309 #include <net/flow.h> 310 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); 311 312 static inline void 313 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 314 { 315 #ifdef CONFIG_NF_NAT_NEEDED 316 void (*decodefn)(struct sk_buff *, struct flowi *); 317 318 if (family == AF_INET) { 319 rcu_read_lock(); 320 decodefn = rcu_dereference(ip_nat_decode_session); 321 if (decodefn) 322 decodefn(skb, fl); 323 rcu_read_unlock(); 324 } 325 #endif 326 } 327 328 #ifdef CONFIG_PROC_FS 329 #include <linux/proc_fs.h> 330 extern struct proc_dir_entry *proc_net_netfilter; 331 #endif 332 333 #else /* !CONFIG_NETFILTER */ 334 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) 335 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) 336 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 337 struct sk_buff *skb, 338 struct net_device *indev, 339 struct net_device *outdev, 340 int (*okfn)(struct sk_buff *), int thresh) 341 { 342 return okfn(skb); 343 } 344 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 345 struct net_device *indev, struct net_device *outdev, 346 int (*okfn)(struct sk_buff *)) 347 { 348 return 1; 349 } 350 struct flowi; 351 static inline void 352 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 353 { 354 } 355 #endif /*CONFIG_NETFILTER*/ 356 357 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 358 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *); 359 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); 360 extern void (*nf_ct_destroy)(struct nf_conntrack *); 361 #else 362 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 363 #endif 364 365 #endif /*__KERNEL__*/ 366 #endif /*__LINUX_NETFILTER_H*/ 367
