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/module.h> 15 #include <linux/netfilter_defs.h> 16 #include <linux/netdevice.h> 17 #include <linux/sockptr.h> 18 #include <net/net_namespace.h> 19 20 static inline int NF_DROP_GETERR(int verdict) 21 { 22 return -(verdict >> NF_VERDICT_QBITS); 23 } 24 25 static __always_inline int 26 NF_DROP_REASON(struct sk_buff *skb, enum skb_drop_reason reason, u32 err) 27 { 28 BUILD_BUG_ON(err > 0xffff); 29 30 kfree_skb_reason(skb, reason); 31 32 return ((err << 16) | NF_STOLEN); 33 } 34 35 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, 36 const union nf_inet_addr *a2) 37 { 38 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 39 const unsigned long *ul1 = (const unsigned long *)a1; 40 const unsigned long *ul2 = (const unsigned long *)a2; 41 42 return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL; 43 #else 44 return a1->all[0] == a2->all[0] && 45 a1->all[1] == a2->all[1] && 46 a1->all[2] == a2->all[2] && 47 a1->all[3] == a2->all[3]; 48 #endif 49 } 50 51 static inline void nf_inet_addr_mask(const union nf_inet_addr *a1, 52 union nf_inet_addr *result, 53 const union nf_inet_addr *mask) 54 { 55 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 56 const unsigned long *ua = (const unsigned long *)a1; 57 unsigned long *ur = (unsigned long *)result; 58 const unsigned long *um = (const unsigned long *)mask; 59 60 ur[0] = ua[0] & um[0]; 61 ur[1] = ua[1] & um[1]; 62 #else 63 result->all[0] = a1->all[0] & mask->all[0]; 64 result->all[1] = a1->all[1] & mask->all[1]; 65 result->all[2] = a1->all[2] & mask->all[2]; 66 result->all[3] = a1->all[3] & mask->all[3]; 67 #endif 68 } 69 70 int netfilter_init(void); 71 72 struct sk_buff; 73 74 struct nf_hook_ops; 75 76 struct sock; 77 78 struct nf_hook_state { 79 u8 hook; 80 u8 pf; 81 struct net_device *in; 82 struct net_device *out; 83 struct sock *sk; 84 struct net *net; 85 int (*okfn)(struct net *, struct sock *, struct sk_buff *); 86 }; 87 88 typedef unsigned int nf_hookfn(void *priv, 89 struct sk_buff *skb, 90 const struct nf_hook_state *state); 91 enum nf_hook_ops_type { 92 NF_HOOK_OP_UNDEFINED, 93 NF_HOOK_OP_NF_TABLES, 94 NF_HOOK_OP_BPF, 95 }; 96 97 struct nf_hook_ops { 98 /* User fills in from here down. */ 99 nf_hookfn *hook; 100 struct net_device *dev; 101 void *priv; 102 u8 pf; 103 enum nf_hook_ops_type hook_ops_type:8; 104 unsigned int hooknum; 105 /* Hooks are ordered in ascending priority. */ 106 int priority; 107 }; 108 109 struct nf_hook_entry { 110 nf_hookfn *hook; 111 void *priv; 112 }; 113 114 struct nf_hook_entries_rcu_head { 115 struct rcu_head head; 116 void *allocation; 117 }; 118 119 struct nf_hook_entries { 120 u16 num_hook_entries; 121 /* padding */ 122 struct nf_hook_entry hooks[]; 123 124 /* trailer: pointers to original orig_ops of each hook, 125 * followed by rcu_head and scratch space used for freeing 126 * the structure via call_rcu. 127 * 128 * This is not part of struct nf_hook_entry since its only 129 * needed in slow path (hook register/unregister): 130 * const struct nf_hook_ops *orig_ops[] 131 * 132 * For the same reason, we store this at end -- its 133 * only needed when a hook is deleted, not during 134 * packet path processing: 135 * struct nf_hook_entries_rcu_head head 136 */ 137 }; 138 139 #ifdef CONFIG_NETFILTER 140 static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e) 141 { 142 unsigned int n = e->num_hook_entries; 143 const void *hook_end; 144 145 hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */ 146 147 return (struct nf_hook_ops **)hook_end; 148 } 149 150 static inline int 151 nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb, 152 struct nf_hook_state *state) 153 { 154 return entry->hook(entry->priv, skb, state); 155 } 156 157 static inline void nf_hook_state_init(struct nf_hook_state *p, 158 unsigned int hook, 159 u_int8_t pf, 160 struct net_device *indev, 161 struct net_device *outdev, 162 struct sock *sk, 163 struct net *net, 164 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 165 { 166 p->hook = hook; 167 p->pf = pf; 168 p->in = indev; 169 p->out = outdev; 170 p->sk = sk; 171 p->net = net; 172 p->okfn = okfn; 173 } 174 175 176 177 struct nf_sockopt_ops { 178 struct list_head list; 179 180 u_int8_t pf; 181 182 /* Non-inclusive ranges: use 0/0/NULL to never get called. */ 183 int set_optmin; 184 int set_optmax; 185 int (*set)(struct sock *sk, int optval, sockptr_t arg, 186 unsigned int len); 187 int get_optmin; 188 int get_optmax; 189 int (*get)(struct sock *sk, int optval, void __user *user, int *len); 190 /* Use the module struct to lock set/get code in place */ 191 struct module *owner; 192 }; 193 194 /* Function to register/unregister hook points. */ 195 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops); 196 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops); 197 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, 198 unsigned int n); 199 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, 200 unsigned int n); 201 202 /* Functions to register get/setsockopt ranges (non-inclusive). You 203 need to check permissions yourself! */ 204 int nf_register_sockopt(struct nf_sockopt_ops *reg); 205 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 206 207 #ifdef CONFIG_JUMP_LABEL 208 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 209 #endif 210 211 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, 212 const struct nf_hook_entries *e, unsigned int i); 213 214 void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state, 215 const struct nf_hook_entries *e); 216 /** 217 * nf_hook - call a netfilter hook 218 * 219 * Returns 1 if the hook has allowed the packet to pass. The function 220 * okfn must be invoked by the caller in this case. Any other return 221 * value indicates the packet has been consumed by the hook. 222 */ 223 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net, 224 struct sock *sk, struct sk_buff *skb, 225 struct net_device *indev, struct net_device *outdev, 226 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 227 { 228 struct nf_hook_entries *hook_head = NULL; 229 int ret = 1; 230 231 #ifdef CONFIG_JUMP_LABEL 232 if (__builtin_constant_p(pf) && 233 __builtin_constant_p(hook) && 234 !static_key_false(&nf_hooks_needed[pf][hook])) 235 return 1; 236 #endif 237 238 rcu_read_lock(); 239 switch (pf) { 240 case NFPROTO_IPV4: 241 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]); 242 break; 243 case NFPROTO_IPV6: 244 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]); 245 break; 246 case NFPROTO_ARP: 247 #ifdef CONFIG_NETFILTER_FAMILY_ARP 248 if (WARN_ON_ONCE(hook >= ARRAY_SIZE(net->nf.hooks_arp))) 249 break; 250 hook_head = rcu_dereference(net->nf.hooks_arp[hook]); 251 #endif 252 break; 253 case NFPROTO_BRIDGE: 254 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE 255 hook_head = rcu_dereference(net->nf.hooks_bridge[hook]); 256 #endif 257 break; 258 default: 259 WARN_ON_ONCE(1); 260 break; 261 } 262 263 if (hook_head) { 264 struct nf_hook_state state; 265 266 nf_hook_state_init(&state, hook, pf, indev, outdev, 267 sk, net, okfn); 268 269 ret = nf_hook_slow(skb, &state, hook_head, 0); 270 } 271 rcu_read_unlock(); 272 273 return ret; 274 } 275 276 /* Activate hook; either okfn or kfree_skb called, unless a hook 277 returns NF_STOLEN (in which case, it's up to the hook to deal with 278 the consequences). 279 280 Returns -ERRNO if packet dropped. Zero means queued, stolen or 281 accepted. 282 */ 283 284 /* RR: 285 > I don't want nf_hook to return anything because people might forget 286 > about async and trust the return value to mean "packet was ok". 287 288 AK: 289 Just document it clearly, then you can expect some sense from kernel 290 coders :) 291 */ 292 293 static inline int 294 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 295 struct sk_buff *skb, struct net_device *in, struct net_device *out, 296 int (*okfn)(struct net *, struct sock *, struct sk_buff *), 297 bool cond) 298 { 299 int ret; 300 301 if (!cond || 302 ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1)) 303 ret = okfn(net, sk, skb); 304 return ret; 305 } 306 307 static inline int 308 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb, 309 struct net_device *in, struct net_device *out, 310 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 311 { 312 int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn); 313 if (ret == 1) 314 ret = okfn(net, sk, skb); 315 return ret; 316 } 317 318 static inline void 319 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 320 struct list_head *head, struct net_device *in, struct net_device *out, 321 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 322 { 323 struct nf_hook_entries *hook_head = NULL; 324 325 #ifdef CONFIG_JUMP_LABEL 326 if (__builtin_constant_p(pf) && 327 __builtin_constant_p(hook) && 328 !static_key_false(&nf_hooks_needed[pf][hook])) 329 return; 330 #endif 331 332 rcu_read_lock(); 333 switch (pf) { 334 case NFPROTO_IPV4: 335 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]); 336 break; 337 case NFPROTO_IPV6: 338 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]); 339 break; 340 default: 341 WARN_ON_ONCE(1); 342 break; 343 } 344 345 if (hook_head) { 346 struct nf_hook_state state; 347 348 nf_hook_state_init(&state, hook, pf, in, out, sk, net, okfn); 349 350 nf_hook_slow_list(head, &state, hook_head); 351 } 352 rcu_read_unlock(); 353 } 354 355 /* Call setsockopt() */ 356 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, sockptr_t opt, 357 unsigned int len); 358 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 359 int *len); 360 361 struct flowi; 362 struct nf_queue_entry; 363 364 __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook, 365 unsigned int dataoff, u_int8_t protocol, 366 unsigned short family); 367 368 __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 369 unsigned int dataoff, unsigned int len, 370 u_int8_t protocol, unsigned short family); 371 int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl, 372 bool strict, unsigned short family); 373 374 #include <net/flow.h> 375 376 struct nf_conn; 377 enum nf_nat_manip_type; 378 struct nlattr; 379 enum ip_conntrack_dir; 380 381 struct nf_nat_hook { 382 int (*parse_nat_setup)(struct nf_conn *ct, enum nf_nat_manip_type manip, 383 const struct nlattr *attr); 384 void (*decode_session)(struct sk_buff *skb, struct flowi *fl); 385 unsigned int (*manip_pkt)(struct sk_buff *skb, struct nf_conn *ct, 386 enum nf_nat_manip_type mtype, 387 enum ip_conntrack_dir dir); 388 void (*remove_nat_bysrc)(struct nf_conn *ct); 389 }; 390 391 extern const struct nf_nat_hook __rcu *nf_nat_hook; 392 393 static inline void 394 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 395 { 396 #if IS_ENABLED(CONFIG_NF_NAT) 397 const struct nf_nat_hook *nat_hook; 398 399 rcu_read_lock(); 400 nat_hook = rcu_dereference(nf_nat_hook); 401 if (nat_hook && nat_hook->decode_session) 402 nat_hook->decode_session(skb, fl); 403 rcu_read_unlock(); 404 #endif 405 } 406 407 #else /* !CONFIG_NETFILTER */ 408 static inline int 409 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 410 struct sk_buff *skb, struct net_device *in, struct net_device *out, 411 int (*okfn)(struct net *, struct sock *, struct sk_buff *), 412 bool cond) 413 { 414 return okfn(net, sk, skb); 415 } 416 417 static inline int 418 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 419 struct sk_buff *skb, struct net_device *in, struct net_device *out, 420 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 421 { 422 return okfn(net, sk, skb); 423 } 424 425 static inline void 426 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 427 struct list_head *head, struct net_device *in, struct net_device *out, 428 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 429 { 430 /* nothing to do */ 431 } 432 433 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net, 434 struct sock *sk, struct sk_buff *skb, 435 struct net_device *indev, struct net_device *outdev, 436 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 437 { 438 return 1; 439 } 440 struct flowi; 441 static inline void 442 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 443 { 444 } 445 #endif /*CONFIG_NETFILTER*/ 446 447 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 448 #include <linux/netfilter/nf_conntrack_zones_common.h> 449 450 void nf_ct_attach(struct sk_buff *, const struct sk_buff *); 451 void nf_ct_set_closing(struct nf_conntrack *nfct); 452 struct nf_conntrack_tuple; 453 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 454 const struct sk_buff *skb); 455 #else 456 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 457 static inline void nf_ct_set_closing(struct nf_conntrack *nfct) {} 458 struct nf_conntrack_tuple; 459 static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 460 const struct sk_buff *skb) 461 { 462 return false; 463 } 464 #endif 465 466 struct nf_conn; 467 enum ip_conntrack_info; 468 469 struct nf_ct_hook { 470 int (*update)(struct net *net, struct sk_buff *skb); 471 void (*destroy)(struct nf_conntrack *); 472 bool (*get_tuple_skb)(struct nf_conntrack_tuple *, 473 const struct sk_buff *); 474 void (*attach)(struct sk_buff *nskb, const struct sk_buff *skb); 475 void (*set_closing)(struct nf_conntrack *nfct); 476 int (*confirm)(struct sk_buff *skb); 477 }; 478 extern const struct nf_ct_hook __rcu *nf_ct_hook; 479 480 struct nlattr; 481 482 struct nfnl_ct_hook { 483 size_t (*build_size)(const struct nf_conn *ct); 484 int (*build)(struct sk_buff *skb, struct nf_conn *ct, 485 enum ip_conntrack_info ctinfo, 486 u_int16_t ct_attr, u_int16_t ct_info_attr); 487 int (*parse)(const struct nlattr *attr, struct nf_conn *ct); 488 int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct, 489 u32 portid, u32 report); 490 void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct, 491 enum ip_conntrack_info ctinfo, s32 off); 492 }; 493 extern const struct nfnl_ct_hook __rcu *nfnl_ct_hook; 494 495 struct nf_defrag_hook { 496 struct module *owner; 497 int (*enable)(struct net *net); 498 void (*disable)(struct net *net); 499 }; 500 501 extern const struct nf_defrag_hook __rcu *nf_defrag_v4_hook; 502 extern const struct nf_defrag_hook __rcu *nf_defrag_v6_hook; 503 504 /* 505 * nf_skb_duplicated - TEE target has sent a packet 506 * 507 * When a xtables target sends a packet, the OUTPUT and POSTROUTING 508 * hooks are traversed again, i.e. nft and xtables are invoked recursively. 509 * 510 * This is used by xtables TEE target to prevent the duplicated skb from 511 * being duplicated again. 512 */ 513 DECLARE_PER_CPU(bool, nf_skb_duplicated); 514 515 /* 516 * Contains bitmask of ctnetlink event subscribers, if any. 517 * Can't be pernet due to NETLINK_LISTEN_ALL_NSID setsockopt flag. 518 */ 519 extern u8 nf_ctnetlink_has_listener; 520 #endif /*__LINUX_NETFILTER_H*/ 521