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