1 #ifndef __LINUX_NETFILTER_H 2 #define __LINUX_NETFILTER_H 3 4 #include <linux/init.h> 5 #include <linux/skbuff.h> 6 #include <linux/net.h> 7 #include <linux/if.h> 8 #include <linux/in.h> 9 #include <linux/in6.h> 10 #include <linux/wait.h> 11 #include <linux/list.h> 12 #include <linux/static_key.h> 13 #include <uapi/linux/netfilter.h> 14 #ifdef CONFIG_NETFILTER 15 static inline int NF_DROP_GETERR(int verdict) 16 { 17 return -(verdict >> NF_VERDICT_QBITS); 18 } 19 20 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 21 const union nf_inet_addr *a2) 22 { 23 return a1->all[0] == a2->all[0] && 24 a1->all[1] == a2->all[1] && 25 a1->all[2] == a2->all[2] && 26 a1->all[3] == a2->all[3]; 27 } 28 29 static inline void nf_inet_addr_mask(const union nf_inet_addr *a1, 30 union nf_inet_addr *result, 31 const union nf_inet_addr *mask) 32 { 33 result->all[0] = a1->all[0] & mask->all[0]; 34 result->all[1] = a1->all[1] & mask->all[1]; 35 result->all[2] = a1->all[2] & mask->all[2]; 36 result->all[3] = a1->all[3] & mask->all[3]; 37 } 38 39 int netfilter_init(void); 40 41 /* Largest hook number + 1 */ 42 #define NF_MAX_HOOKS 8 43 44 struct sk_buff; 45 46 struct nf_hook_ops; 47 48 struct sock; 49 50 struct nf_hook_state { 51 unsigned int hook; 52 int thresh; 53 u_int8_t pf; 54 struct net_device *in; 55 struct net_device *out; 56 struct sock *sk; 57 int (*okfn)(struct sock *, struct sk_buff *); 58 }; 59 60 static inline void nf_hook_state_init(struct nf_hook_state *p, 61 unsigned int hook, 62 int thresh, u_int8_t pf, 63 struct net_device *indev, 64 struct net_device *outdev, 65 struct sock *sk, 66 int (*okfn)(struct sock *, struct sk_buff *)) 67 { 68 p->hook = hook; 69 p->thresh = thresh; 70 p->pf = pf; 71 p->in = indev; 72 p->out = outdev; 73 p->sk = sk; 74 p->okfn = okfn; 75 } 76 77 typedef unsigned int nf_hookfn(const struct nf_hook_ops *ops, 78 struct sk_buff *skb, 79 const struct nf_hook_state *state); 80 81 struct nf_hook_ops { 82 struct list_head list; 83 84 /* User fills in from here down. */ 85 nf_hookfn *hook; 86 struct module *owner; 87 void *priv; 88 u_int8_t pf; 89 unsigned int hooknum; 90 /* Hooks are ordered in ascending priority. */ 91 int priority; 92 }; 93 94 struct nf_sockopt_ops { 95 struct list_head list; 96 97 u_int8_t pf; 98 99 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 100 int set_optmin; 101 int set_optmax; 102 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len); 103 #ifdef CONFIG_COMPAT 104 int (*compat_set)(struct sock *sk, int optval, 105 void __user *user, unsigned int len); 106 #endif 107 int get_optmin; 108 int get_optmax; 109 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 110 #ifdef CONFIG_COMPAT 111 int (*compat_get)(struct sock *sk, int optval, 112 void __user *user, int *len); 113 #endif 114 /* Use the module struct to lock set/get code in place */ 115 struct module *owner; 116 }; 117 118 /* Function to register/unregister hook points. */ 119 int nf_register_hook(struct nf_hook_ops *reg); 120 void nf_unregister_hook(struct nf_hook_ops *reg); 121 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); 122 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); 123 124 /* Functions to register get/setsockopt ranges (non-inclusive). You 125 need to check permissions yourself! */ 126 int nf_register_sockopt(struct nf_sockopt_ops *reg); 127 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 128 129 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 130 131 #ifdef HAVE_JUMP_LABEL 132 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 133 134 static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) 135 { 136 if (__builtin_constant_p(pf) && 137 __builtin_constant_p(hook)) 138 return static_key_false(&nf_hooks_needed[pf][hook]); 139 140 return !list_empty(&nf_hooks[pf][hook]); 141 } 142 #else 143 static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) 144 { 145 return !list_empty(&nf_hooks[pf][hook]); 146 } 147 #endif 148 149 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state); 150 151 /** 152 * nf_hook_thresh - call a netfilter hook 153 * 154 * Returns 1 if the hook has allowed the packet to pass. The function 155 * okfn must be invoked by the caller in this case. Any other return 156 * value indicates the packet has been consumed by the hook. 157 */ 158 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 159 struct sock *sk, 160 struct sk_buff *skb, 161 struct net_device *indev, 162 struct net_device *outdev, 163 int (*okfn)(struct sock *, struct sk_buff *), 164 int thresh) 165 { 166 if (nf_hooks_active(pf, hook)) { 167 struct nf_hook_state state; 168 169 nf_hook_state_init(&state, hook, thresh, pf, 170 indev, outdev, sk, okfn); 171 return nf_hook_slow(skb, &state); 172 } 173 return 1; 174 } 175 176 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sock *sk, 177 struct sk_buff *skb, struct net_device *indev, 178 struct net_device *outdev, 179 int (*okfn)(struct sock *, struct sk_buff *)) 180 { 181 return nf_hook_thresh(pf, hook, sk, 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 sock *sk, 203 struct sk_buff *skb, struct net_device *in, 204 struct net_device *out, 205 int (*okfn)(struct sock *, struct sk_buff *), int thresh) 206 { 207 int ret = nf_hook_thresh(pf, hook, sk, skb, in, out, okfn, thresh); 208 if (ret == 1) 209 ret = okfn(sk, skb); 210 return ret; 211 } 212 213 static inline int 214 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sock *sk, 215 struct sk_buff *skb, struct net_device *in, struct net_device *out, 216 int (*okfn)(struct sock *, struct sk_buff *), bool cond) 217 { 218 int ret; 219 220 if (!cond || 221 ((ret = nf_hook_thresh(pf, hook, sk, skb, in, out, okfn, INT_MIN)) == 1)) 222 ret = okfn(sk, skb); 223 return ret; 224 } 225 226 static inline int 227 NF_HOOK(uint8_t pf, unsigned int hook, struct sock *sk, struct sk_buff *skb, 228 struct net_device *in, struct net_device *out, 229 int (*okfn)(struct sock *, struct sk_buff *)) 230 { 231 return NF_HOOK_THRESH(pf, hook, sk, skb, in, out, okfn, INT_MIN); 232 } 233 234 /* Call setsockopt() */ 235 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 236 unsigned int len); 237 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 238 int *len); 239 #ifdef CONFIG_COMPAT 240 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 241 char __user *opt, unsigned int len); 242 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 243 char __user *opt, int *len); 244 #endif 245 246 /* Call this before modifying an existing packet: ensures it is 247 modifiable and linear to the point you care about (writable_len). 248 Returns true or false. */ 249 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 250 251 struct flowi; 252 struct nf_queue_entry; 253 254 struct nf_afinfo { 255 unsigned short family; 256 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, 257 unsigned int dataoff, u_int8_t protocol); 258 __sum16 (*checksum_partial)(struct sk_buff *skb, 259 unsigned int hook, 260 unsigned int dataoff, 261 unsigned int len, 262 u_int8_t protocol); 263 int (*route)(struct net *net, struct dst_entry **dst, 264 struct flowi *fl, bool strict); 265 void (*saveroute)(const struct sk_buff *skb, 266 struct nf_queue_entry *entry); 267 int (*reroute)(struct sk_buff *skb, 268 const struct nf_queue_entry *entry); 269 int route_key_size; 270 }; 271 272 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO]; 273 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) 274 { 275 return rcu_dereference(nf_afinfo[family]); 276 } 277 278 static inline __sum16 279 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 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(skb, hook, dataoff, protocol); 289 rcu_read_unlock(); 290 return csum; 291 } 292 293 static inline __sum16 294 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 295 unsigned int dataoff, unsigned int len, 296 u_int8_t protocol, unsigned short family) 297 { 298 const struct nf_afinfo *afinfo; 299 __sum16 csum = 0; 300 301 rcu_read_lock(); 302 afinfo = nf_get_afinfo(family); 303 if (afinfo) 304 csum = afinfo->checksum_partial(skb, hook, dataoff, len, 305 protocol); 306 rcu_read_unlock(); 307 return csum; 308 } 309 310 int nf_register_afinfo(const struct nf_afinfo *afinfo); 311 void nf_unregister_afinfo(const struct nf_afinfo *afinfo); 312 313 #include <net/flow.h> 314 extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *); 315 316 static inline void 317 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 318 { 319 #ifdef CONFIG_NF_NAT_NEEDED 320 void (*decodefn)(struct sk_buff *, struct flowi *); 321 322 rcu_read_lock(); 323 decodefn = rcu_dereference(nf_nat_decode_session_hook); 324 if (decodefn) 325 decodefn(skb, fl); 326 rcu_read_unlock(); 327 #endif 328 } 329 330 #else /* !CONFIG_NETFILTER */ 331 #define NF_HOOK(pf, hook, sk, skb, indev, outdev, okfn) (okfn)(sk, skb) 332 #define NF_HOOK_COND(pf, hook, sk, skb, indev, outdev, okfn, cond) (okfn)(sk, skb) 333 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, 334 struct sock *sk, 335 struct sk_buff *skb, 336 struct net_device *indev, 337 struct net_device *outdev, 338 int (*okfn)(struct sock *sk, struct sk_buff *), int thresh) 339 { 340 return okfn(sk, skb); 341 } 342 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sock *sk, 343 struct sk_buff *skb, struct net_device *indev, 344 struct net_device *outdev, 345 int (*okfn)(struct sock *, struct sk_buff *)) 346 { 347 return 1; 348 } 349 struct flowi; 350 static inline void 351 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 352 { 353 } 354 #endif /*CONFIG_NETFILTER*/ 355 356 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 357 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu; 358 void nf_ct_attach(struct sk_buff *, const struct sk_buff *); 359 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu; 360 361 struct nf_conn; 362 enum ip_conntrack_info; 363 struct nlattr; 364 365 struct nfq_ct_hook { 366 size_t (*build_size)(const struct nf_conn *ct); 367 int (*build)(struct sk_buff *skb, struct nf_conn *ct); 368 int (*parse)(const struct nlattr *attr, struct nf_conn *ct); 369 int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct, 370 u32 portid, u32 report); 371 void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct, 372 enum ip_conntrack_info ctinfo, s32 off); 373 }; 374 extern struct nfq_ct_hook __rcu *nfq_ct_hook; 375 #else 376 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 377 #endif 378 379 #endif /*__LINUX_NETFILTER_H*/ 380