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