1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_NETFILTER_H 3 #define __LINUX_NETFILTER_H 4 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 #include <linux/static_key.h> 14 #include <linux/netfilter_defs.h> 15 #include <linux/netdevice.h> 16 #include <linux/sockptr.h> 17 #include <net/net_namespace.h> 18 19 static inline int NF_DROP_GETERR(int verdict) 20 { 21 return -(verdict >> NF_VERDICT_QBITS); 22 } 23 24 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 25 const union nf_inet_addr *a2) 26 { 27 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 28 const unsigned long *ul1 = (const unsigned long *)a1; 29 const unsigned long *ul2 = (const unsigned long *)a2; 30 31 return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL; 32 #else 33 return a1->all[0] == a2->all[0] && 34 a1->all[1] == a2->all[1] && 35 a1->all[2] == a2->all[2] && 36 a1->all[3] == a2->all[3]; 37 #endif 38 } 39 40 static inline void nf_inet_addr_mask(const union nf_inet_addr *a1, 41 union nf_inet_addr *result, 42 const union nf_inet_addr *mask) 43 { 44 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 45 const unsigned long *ua = (const unsigned long *)a1; 46 unsigned long *ur = (unsigned long *)result; 47 const unsigned long *um = (const unsigned long *)mask; 48 49 ur[0] = ua[0] & um[0]; 50 ur[1] = ua[1] & um[1]; 51 #else 52 result->all[0] = a1->all[0] & mask->all[0]; 53 result->all[1] = a1->all[1] & mask->all[1]; 54 result->all[2] = a1->all[2] & mask->all[2]; 55 result->all[3] = a1->all[3] & mask->all[3]; 56 #endif 57 } 58 59 int netfilter_init(void); 60 61 struct sk_buff; 62 63 struct nf_hook_ops; 64 65 struct sock; 66 67 struct nf_hook_state { 68 u8 hook; 69 u8 pf; 70 struct net_device *in; 71 struct net_device *out; 72 struct sock *sk; 73 struct net *net; 74 int (*okfn)(struct net *, struct sock *, struct sk_buff *); 75 }; 76 77 typedef unsigned int nf_hookfn(void *priv, 78 struct sk_buff *skb, 79 const struct nf_hook_state *state); 80 enum nf_hook_ops_type { 81 NF_HOOK_OP_UNDEFINED, 82 NF_HOOK_OP_NF_TABLES, 83 NF_HOOK_OP_BPF, 84 }; 85 86 struct nf_hook_ops { 87 /* User fills in from here down. */ 88 nf_hookfn *hook; 89 struct net_device *dev; 90 void *priv; 91 u8 pf; 92 enum nf_hook_ops_type hook_ops_type:8; 93 unsigned int hooknum; 94 /* Hooks are ordered in ascending priority. */ 95 int priority; 96 }; 97 98 struct nf_hook_entry { 99 nf_hookfn *hook; 100 void *priv; 101 }; 102 103 struct nf_hook_entries_rcu_head { 104 struct rcu_head head; 105 void *allocation; 106 }; 107 108 struct nf_hook_entries { 109 u16 num_hook_entries; 110 /* padding */ 111 struct nf_hook_entry hooks[]; 112 113 /* trailer: pointers to original orig_ops of each hook, 114 * followed by rcu_head and scratch space used for freeing 115 * the structure via call_rcu. 116 * 117 * This is not part of struct nf_hook_entry since its only 118 * needed in slow path (hook register/unregister): 119 * const struct nf_hook_ops *orig_ops[] 120 * 121 * For the same reason, we store this at end -- its 122 * only needed when a hook is deleted, not during 123 * packet path processing: 124 * struct nf_hook_entries_rcu_head head 125 */ 126 }; 127 128 #ifdef CONFIG_NETFILTER 129 static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e) 130 { 131 unsigned int n = e->num_hook_entries; 132 const void *hook_end; 133 134 hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */ 135 136 return (struct nf_hook_ops **)hook_end; 137 } 138 139 static inline int 140 nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb, 141 struct nf_hook_state *state) 142 { 143 return entry->hook(entry->priv, skb, state); 144 } 145 146 static inline void nf_hook_state_init(struct nf_hook_state *p, 147 unsigned int hook, 148 u_int8_t pf, 149 struct net_device *indev, 150 struct net_device *outdev, 151 struct sock *sk, 152 struct net *net, 153 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 154 { 155 p->hook = hook; 156 p->pf = pf; 157 p->in = indev; 158 p->out = outdev; 159 p->sk = sk; 160 p->net = net; 161 p->okfn = okfn; 162 } 163 164 165 166 struct nf_sockopt_ops { 167 struct list_head list; 168 169 u_int8_t pf; 170 171 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 172 int set_optmin; 173 int set_optmax; 174 int (*set)(struct sock *sk, int optval, sockptr_t arg, 175 unsigned int len); 176 int get_optmin; 177 int get_optmax; 178 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 179 /* Use the module struct to lock set/get code in place */ 180 struct module *owner; 181 }; 182 183 /* Function to register/unregister hook points. */ 184 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops); 185 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops); 186 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, 187 unsigned int n); 188 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, 189 unsigned int n); 190 191 /* Functions to register get/setsockopt ranges (non-inclusive). You 192 need to check permissions yourself! */ 193 int nf_register_sockopt(struct nf_sockopt_ops *reg); 194 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 195 196 #ifdef CONFIG_JUMP_LABEL 197 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 198 #endif 199 200 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, 201 const struct nf_hook_entries *e, unsigned int i); 202 203 void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state, 204 const struct nf_hook_entries *e); 205 /** 206 * nf_hook - call a netfilter hook 207 * 208 * Returns 1 if the hook has allowed the packet to pass. The function 209 * okfn must be invoked by the caller in this case. Any other return 210 * value indicates the packet has been consumed by the hook. 211 */ 212 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net, 213 struct sock *sk, struct sk_buff *skb, 214 struct net_device *indev, struct net_device *outdev, 215 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 216 { 217 struct nf_hook_entries *hook_head = NULL; 218 int ret = 1; 219 220 #ifdef CONFIG_JUMP_LABEL 221 if (__builtin_constant_p(pf) && 222 __builtin_constant_p(hook) && 223 !static_key_false(&nf_hooks_needed[pf][hook])) 224 return 1; 225 #endif 226 227 rcu_read_lock(); 228 switch (pf) { 229 case NFPROTO_IPV4: 230 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]); 231 break; 232 case NFPROTO_IPV6: 233 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]); 234 break; 235 case NFPROTO_ARP: 236 #ifdef CONFIG_NETFILTER_FAMILY_ARP 237 if (WARN_ON_ONCE(hook >= ARRAY_SIZE(net->nf.hooks_arp))) 238 break; 239 hook_head = rcu_dereference(net->nf.hooks_arp[hook]); 240 #endif 241 break; 242 case NFPROTO_BRIDGE: 243 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE 244 hook_head = rcu_dereference(net->nf.hooks_bridge[hook]); 245 #endif 246 break; 247 default: 248 WARN_ON_ONCE(1); 249 break; 250 } 251 252 if (hook_head) { 253 struct nf_hook_state state; 254 255 nf_hook_state_init(&state, hook, pf, indev, outdev, 256 sk, net, okfn); 257 258 ret = nf_hook_slow(skb, &state, hook_head, 0); 259 } 260 rcu_read_unlock(); 261 262 return ret; 263 } 264 265 /* Activate hook; either okfn or kfree_skb called, unless a hook 266 returns NF_STOLEN (in which case, it's up to the hook to deal with 267 the consequences). 268 269 Returns -ERRNO if packet dropped. Zero means queued, stolen or 270 accepted. 271 */ 272 273 /* RR: 274 > I don't want nf_hook to return anything because people might forget 275 > about async and trust the return value to mean "packet was ok". 276 277 AK: 278 Just document it clearly, then you can expect some sense from kernel 279 coders :) 280 */ 281 282 static inline int 283 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 284 struct sk_buff *skb, struct net_device *in, struct net_device *out, 285 int (*okfn)(struct net *, struct sock *, struct sk_buff *), 286 bool cond) 287 { 288 int ret; 289 290 if (!cond || 291 ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1)) 292 ret = okfn(net, sk, skb); 293 return ret; 294 } 295 296 static inline int 297 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb, 298 struct net_device *in, struct net_device *out, 299 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 300 { 301 int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn); 302 if (ret == 1) 303 ret = okfn(net, sk, skb); 304 return ret; 305 } 306 307 static inline void 308 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 309 struct list_head *head, struct net_device *in, struct net_device *out, 310 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 311 { 312 struct nf_hook_entries *hook_head = NULL; 313 314 #ifdef CONFIG_JUMP_LABEL 315 if (__builtin_constant_p(pf) && 316 __builtin_constant_p(hook) && 317 !static_key_false(&nf_hooks_needed[pf][hook])) 318 return; 319 #endif 320 321 rcu_read_lock(); 322 switch (pf) { 323 case NFPROTO_IPV4: 324 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]); 325 break; 326 case NFPROTO_IPV6: 327 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]); 328 break; 329 default: 330 WARN_ON_ONCE(1); 331 break; 332 } 333 334 if (hook_head) { 335 struct nf_hook_state state; 336 337 nf_hook_state_init(&state, hook, pf, in, out, sk, net, okfn); 338 339 nf_hook_slow_list(head, &state, hook_head); 340 } 341 rcu_read_unlock(); 342 } 343 344 /* Call setsockopt() */ 345 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, sockptr_t opt, 346 unsigned int len); 347 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 348 int *len); 349 350 struct flowi; 351 struct nf_queue_entry; 352 353 __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook, 354 unsigned int dataoff, u_int8_t protocol, 355 unsigned short family); 356 357 __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 358 unsigned int dataoff, unsigned int len, 359 u_int8_t protocol, unsigned short family); 360 int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl, 361 bool strict, unsigned short family); 362 int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry); 363 364 #include <net/flow.h> 365 366 struct nf_conn; 367 enum nf_nat_manip_type; 368 struct nlattr; 369 enum ip_conntrack_dir; 370 371 struct nf_nat_hook { 372 int (*parse_nat_setup)(struct nf_conn *ct, enum nf_nat_manip_type manip, 373 const struct nlattr *attr); 374 void (*decode_session)(struct sk_buff *skb, struct flowi *fl); 375 unsigned int (*manip_pkt)(struct sk_buff *skb, struct nf_conn *ct, 376 enum nf_nat_manip_type mtype, 377 enum ip_conntrack_dir dir); 378 void (*remove_nat_bysrc)(struct nf_conn *ct); 379 }; 380 381 extern const struct nf_nat_hook __rcu *nf_nat_hook; 382 383 static inline void 384 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 385 { 386 #if IS_ENABLED(CONFIG_NF_NAT) 387 const struct nf_nat_hook *nat_hook; 388 389 rcu_read_lock(); 390 nat_hook = rcu_dereference(nf_nat_hook); 391 if (nat_hook && nat_hook->decode_session) 392 nat_hook->decode_session(skb, fl); 393 rcu_read_unlock(); 394 #endif 395 } 396 397 #else /* !CONFIG_NETFILTER */ 398 static inline int 399 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 400 struct sk_buff *skb, struct net_device *in, struct net_device *out, 401 int (*okfn)(struct net *, struct sock *, struct sk_buff *), 402 bool cond) 403 { 404 return okfn(net, sk, skb); 405 } 406 407 static inline int 408 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 409 struct sk_buff *skb, struct net_device *in, struct net_device *out, 410 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 411 { 412 return okfn(net, sk, skb); 413 } 414 415 static inline void 416 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 417 struct list_head *head, struct net_device *in, struct net_device *out, 418 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 419 { 420 /* nothing to do */ 421 } 422 423 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net, 424 struct sock *sk, struct sk_buff *skb, 425 struct net_device *indev, struct net_device *outdev, 426 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 427 { 428 return 1; 429 } 430 struct flowi; 431 static inline void 432 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 433 { 434 } 435 #endif /*CONFIG_NETFILTER*/ 436 437 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 438 #include <linux/netfilter/nf_conntrack_zones_common.h> 439 440 void nf_ct_attach(struct sk_buff *, const struct sk_buff *); 441 void nf_ct_set_closing(struct nf_conntrack *nfct); 442 struct nf_conntrack_tuple; 443 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 444 const struct sk_buff *skb); 445 #else 446 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 447 static inline void nf_ct_set_closing(struct nf_conntrack *nfct) {} 448 struct nf_conntrack_tuple; 449 static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 450 const struct sk_buff *skb) 451 { 452 return false; 453 } 454 #endif 455 456 struct nf_conn; 457 enum ip_conntrack_info; 458 459 struct nf_ct_hook { 460 int (*update)(struct net *net, struct sk_buff *skb); 461 void (*destroy)(struct nf_conntrack *); 462 bool (*get_tuple_skb)(struct nf_conntrack_tuple *, 463 const struct sk_buff *); 464 void (*attach)(struct sk_buff *nskb, const struct sk_buff *skb); 465 void (*set_closing)(struct nf_conntrack *nfct); 466 }; 467 extern const struct nf_ct_hook __rcu *nf_ct_hook; 468 469 struct nlattr; 470 471 struct nfnl_ct_hook { 472 size_t (*build_size)(const struct nf_conn *ct); 473 int (*build)(struct sk_buff *skb, struct nf_conn *ct, 474 enum ip_conntrack_info ctinfo, 475 u_int16_t ct_attr, u_int16_t ct_info_attr); 476 int (*parse)(const struct nlattr *attr, struct nf_conn *ct); 477 int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct, 478 u32 portid, u32 report); 479 void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct, 480 enum ip_conntrack_info ctinfo, s32 off); 481 }; 482 extern const struct nfnl_ct_hook __rcu *nfnl_ct_hook; 483 484 /** 485 * nf_skb_duplicated - TEE target has sent a packet 486 * 487 * When a xtables target sends a packet, the OUTPUT and POSTROUTING 488 * hooks are traversed again, i.e. nft and xtables are invoked recursively. 489 * 490 * This is used by xtables TEE target to prevent the duplicated skb from 491 * being duplicated again. 492 */ 493 DECLARE_PER_CPU(bool, nf_skb_duplicated); 494 495 /** 496 * Contains bitmask of ctnetlink event subscribers, if any. 497 * Can't be pernet due to NETLINK_LISTEN_ALL_NSID setsockopt flag. 498 */ 499 extern u8 nf_ctnetlink_has_listener; 500 #endif /*__LINUX_NETFILTER_H*/ 501