1 #ifndef _X_TABLES_H 2 #define _X_TABLES_H 3 4 5 #include <linux/netdevice.h> 6 #include <linux/static_key.h> 7 #include <uapi/linux/netfilter/x_tables.h> 8 9 /** 10 * struct xt_action_param - parameters for matches/targets 11 * 12 * @match: the match extension 13 * @target: the target extension 14 * @matchinfo: per-match data 15 * @targetinfo: per-target data 16 * @net network namespace through which the action was invoked 17 * @in: input netdevice 18 * @out: output netdevice 19 * @fragoff: packet is a fragment, this is the data offset 20 * @thoff: position of transport header relative to skb->data 21 * @hook: hook number given packet came from 22 * @family: Actual NFPROTO_* through which the function is invoked 23 * (helpful when match->family == NFPROTO_UNSPEC) 24 * 25 * Fields written to by extensions: 26 * 27 * @hotdrop: drop packet if we had inspection problems 28 */ 29 struct xt_action_param { 30 union { 31 const struct xt_match *match; 32 const struct xt_target *target; 33 }; 34 union { 35 const void *matchinfo, *targinfo; 36 }; 37 struct net *net; 38 const struct net_device *in, *out; 39 int fragoff; 40 unsigned int thoff; 41 unsigned int hooknum; 42 u_int8_t family; 43 bool hotdrop; 44 }; 45 46 /** 47 * struct xt_mtchk_param - parameters for match extensions' 48 * checkentry functions 49 * 50 * @net: network namespace through which the check was invoked 51 * @table: table the rule is tried to be inserted into 52 * @entryinfo: the family-specific rule data 53 * (struct ipt_ip, ip6t_ip, arpt_arp or (note) ebt_entry) 54 * @match: struct xt_match through which this function was invoked 55 * @matchinfo: per-match data 56 * @hook_mask: via which hooks the new rule is reachable 57 * Other fields as above. 58 */ 59 struct xt_mtchk_param { 60 struct net *net; 61 const char *table; 62 const void *entryinfo; 63 const struct xt_match *match; 64 void *matchinfo; 65 unsigned int hook_mask; 66 u_int8_t family; 67 bool nft_compat; 68 }; 69 70 /** 71 * struct xt_mdtor_param - match destructor parameters 72 * Fields as above. 73 */ 74 struct xt_mtdtor_param { 75 struct net *net; 76 const struct xt_match *match; 77 void *matchinfo; 78 u_int8_t family; 79 }; 80 81 /** 82 * struct xt_tgchk_param - parameters for target extensions' 83 * checkentry functions 84 * 85 * @entryinfo: the family-specific rule data 86 * (struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry) 87 * 88 * Other fields see above. 89 */ 90 struct xt_tgchk_param { 91 struct net *net; 92 const char *table; 93 const void *entryinfo; 94 const struct xt_target *target; 95 void *targinfo; 96 unsigned int hook_mask; 97 u_int8_t family; 98 bool nft_compat; 99 }; 100 101 /* Target destructor parameters */ 102 struct xt_tgdtor_param { 103 struct net *net; 104 const struct xt_target *target; 105 void *targinfo; 106 u_int8_t family; 107 }; 108 109 struct xt_match { 110 struct list_head list; 111 112 const char name[XT_EXTENSION_MAXNAMELEN]; 113 u_int8_t revision; 114 115 /* Return true or false: return FALSE and set *hotdrop = 1 to 116 force immediate packet drop. */ 117 /* Arguments changed since 2.6.9, as this must now handle 118 non-linear skb, using skb_header_pointer and 119 skb_ip_make_writable. */ 120 bool (*match)(const struct sk_buff *skb, 121 struct xt_action_param *); 122 123 /* Called when user tries to insert an entry of this type. */ 124 int (*checkentry)(const struct xt_mtchk_param *); 125 126 /* Called when entry of this type deleted. */ 127 void (*destroy)(const struct xt_mtdtor_param *); 128 #ifdef CONFIG_COMPAT 129 /* Called when userspace align differs from kernel space one */ 130 void (*compat_from_user)(void *dst, const void *src); 131 int (*compat_to_user)(void __user *dst, const void *src); 132 #endif 133 /* Set this to THIS_MODULE if you are a module, otherwise NULL */ 134 struct module *me; 135 136 const char *table; 137 unsigned int matchsize; 138 #ifdef CONFIG_COMPAT 139 unsigned int compatsize; 140 #endif 141 unsigned int hooks; 142 unsigned short proto; 143 144 unsigned short family; 145 }; 146 147 /* Registration hooks for targets. */ 148 struct xt_target { 149 struct list_head list; 150 151 const char name[XT_EXTENSION_MAXNAMELEN]; 152 u_int8_t revision; 153 154 /* Returns verdict. Argument order changed since 2.6.9, as this 155 must now handle non-linear skbs, using skb_copy_bits and 156 skb_ip_make_writable. */ 157 unsigned int (*target)(struct sk_buff *skb, 158 const struct xt_action_param *); 159 160 /* Called when user tries to insert an entry of this type: 161 hook_mask is a bitmask of hooks from which it can be 162 called. */ 163 /* Should return 0 on success or an error code otherwise (-Exxxx). */ 164 int (*checkentry)(const struct xt_tgchk_param *); 165 166 /* Called when entry of this type deleted. */ 167 void (*destroy)(const struct xt_tgdtor_param *); 168 #ifdef CONFIG_COMPAT 169 /* Called when userspace align differs from kernel space one */ 170 void (*compat_from_user)(void *dst, const void *src); 171 int (*compat_to_user)(void __user *dst, const void *src); 172 #endif 173 /* Set this to THIS_MODULE if you are a module, otherwise NULL */ 174 struct module *me; 175 176 const char *table; 177 unsigned int targetsize; 178 #ifdef CONFIG_COMPAT 179 unsigned int compatsize; 180 #endif 181 unsigned int hooks; 182 unsigned short proto; 183 184 unsigned short family; 185 }; 186 187 /* Furniture shopping... */ 188 struct xt_table { 189 struct list_head list; 190 191 /* What hooks you will enter on */ 192 unsigned int valid_hooks; 193 194 /* Man behind the curtain... */ 195 struct xt_table_info *private; 196 197 /* Set this to THIS_MODULE if you are a module, otherwise NULL */ 198 struct module *me; 199 200 u_int8_t af; /* address/protocol family */ 201 int priority; /* hook order */ 202 203 /* called when table is needed in the given netns */ 204 int (*table_init)(struct net *net); 205 206 /* A unique name... */ 207 const char name[XT_TABLE_MAXNAMELEN]; 208 }; 209 210 #include <linux/netfilter_ipv4.h> 211 212 /* The table itself */ 213 struct xt_table_info { 214 /* Size per table */ 215 unsigned int size; 216 /* Number of entries: FIXME. --RR */ 217 unsigned int number; 218 /* Initial number of entries. Needed for module usage count */ 219 unsigned int initial_entries; 220 221 /* Entry points and underflows */ 222 unsigned int hook_entry[NF_INET_NUMHOOKS]; 223 unsigned int underflow[NF_INET_NUMHOOKS]; 224 225 /* 226 * Number of user chains. Since tables cannot have loops, at most 227 * @stacksize jumps (number of user chains) can possibly be made. 228 */ 229 unsigned int stacksize; 230 void ***jumpstack; 231 232 unsigned char entries[0] __aligned(8); 233 }; 234 235 int xt_register_target(struct xt_target *target); 236 void xt_unregister_target(struct xt_target *target); 237 int xt_register_targets(struct xt_target *target, unsigned int n); 238 void xt_unregister_targets(struct xt_target *target, unsigned int n); 239 240 int xt_register_match(struct xt_match *target); 241 void xt_unregister_match(struct xt_match *target); 242 int xt_register_matches(struct xt_match *match, unsigned int n); 243 void xt_unregister_matches(struct xt_match *match, unsigned int n); 244 245 int xt_check_entry_offsets(const void *base, const char *elems, 246 unsigned int target_offset, 247 unsigned int next_offset); 248 249 int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto, 250 bool inv_proto); 251 int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto, 252 bool inv_proto); 253 254 void *xt_copy_counters_from_user(const void __user *user, unsigned int len, 255 struct xt_counters_info *info, bool compat); 256 257 struct xt_table *xt_register_table(struct net *net, 258 const struct xt_table *table, 259 struct xt_table_info *bootstrap, 260 struct xt_table_info *newinfo); 261 void *xt_unregister_table(struct xt_table *table); 262 263 struct xt_table_info *xt_replace_table(struct xt_table *table, 264 unsigned int num_counters, 265 struct xt_table_info *newinfo, 266 int *error); 267 268 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision); 269 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision); 270 struct xt_match *xt_request_find_match(u8 af, const char *name, u8 revision); 271 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision); 272 int xt_find_revision(u8 af, const char *name, u8 revision, int target, 273 int *err); 274 275 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, 276 const char *name); 277 void xt_table_unlock(struct xt_table *t); 278 279 int xt_proto_init(struct net *net, u_int8_t af); 280 void xt_proto_fini(struct net *net, u_int8_t af); 281 282 struct xt_table_info *xt_alloc_table_info(unsigned int size); 283 void xt_free_table_info(struct xt_table_info *info); 284 285 /** 286 * xt_recseq - recursive seqcount for netfilter use 287 * 288 * Packet processing changes the seqcount only if no recursion happened 289 * get_counters() can use read_seqcount_begin()/read_seqcount_retry(), 290 * because we use the normal seqcount convention : 291 * Low order bit set to 1 if a writer is active. 292 */ 293 DECLARE_PER_CPU(seqcount_t, xt_recseq); 294 295 /* xt_tee_enabled - true if x_tables needs to handle reentrancy 296 * 297 * Enabled if current ip(6)tables ruleset has at least one -j TEE rule. 298 */ 299 extern struct static_key xt_tee_enabled; 300 301 /** 302 * xt_write_recseq_begin - start of a write section 303 * 304 * Begin packet processing : all readers must wait the end 305 * 1) Must be called with preemption disabled 306 * 2) softirqs must be disabled too (or we should use this_cpu_add()) 307 * Returns : 308 * 1 if no recursion on this cpu 309 * 0 if recursion detected 310 */ 311 static inline unsigned int xt_write_recseq_begin(void) 312 { 313 unsigned int addend; 314 315 /* 316 * Low order bit of sequence is set if we already 317 * called xt_write_recseq_begin(). 318 */ 319 addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1; 320 321 /* 322 * This is kind of a write_seqcount_begin(), but addend is 0 or 1 323 * We dont check addend value to avoid a test and conditional jump, 324 * since addend is most likely 1 325 */ 326 __this_cpu_add(xt_recseq.sequence, addend); 327 smp_wmb(); 328 329 return addend; 330 } 331 332 /** 333 * xt_write_recseq_end - end of a write section 334 * @addend: return value from previous xt_write_recseq_begin() 335 * 336 * End packet processing : all readers can proceed 337 * 1) Must be called with preemption disabled 338 * 2) softirqs must be disabled too (or we should use this_cpu_add()) 339 */ 340 static inline void xt_write_recseq_end(unsigned int addend) 341 { 342 /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */ 343 smp_wmb(); 344 __this_cpu_add(xt_recseq.sequence, addend); 345 } 346 347 /* 348 * This helper is performance critical and must be inlined 349 */ 350 static inline unsigned long ifname_compare_aligned(const char *_a, 351 const char *_b, 352 const char *_mask) 353 { 354 const unsigned long *a = (const unsigned long *)_a; 355 const unsigned long *b = (const unsigned long *)_b; 356 const unsigned long *mask = (const unsigned long *)_mask; 357 unsigned long ret; 358 359 ret = (a[0] ^ b[0]) & mask[0]; 360 if (IFNAMSIZ > sizeof(unsigned long)) 361 ret |= (a[1] ^ b[1]) & mask[1]; 362 if (IFNAMSIZ > 2 * sizeof(unsigned long)) 363 ret |= (a[2] ^ b[2]) & mask[2]; 364 if (IFNAMSIZ > 3 * sizeof(unsigned long)) 365 ret |= (a[3] ^ b[3]) & mask[3]; 366 BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); 367 return ret; 368 } 369 370 371 /* On SMP, ip(6)t_entry->counters.pcnt holds address of the 372 * real (percpu) counter. On !SMP, its just the packet count, 373 * so nothing needs to be done there. 374 * 375 * xt_percpu_counter_alloc returns the address of the percpu 376 * counter, or 0 on !SMP. We force an alignment of 16 bytes 377 * so that bytes/packets share a common cache line. 378 * 379 * Hence caller must use IS_ERR_VALUE to check for error, this 380 * allows us to return 0 for single core systems without forcing 381 * callers to deal with SMP vs. NONSMP issues. 382 */ 383 static inline unsigned long xt_percpu_counter_alloc(void) 384 { 385 if (nr_cpu_ids > 1) { 386 void __percpu *res = __alloc_percpu(sizeof(struct xt_counters), 387 sizeof(struct xt_counters)); 388 389 if (res == NULL) 390 return -ENOMEM; 391 392 return (__force unsigned long) res; 393 } 394 395 return 0; 396 } 397 static inline void xt_percpu_counter_free(u64 pcnt) 398 { 399 if (nr_cpu_ids > 1) 400 free_percpu((void __percpu *) (unsigned long) pcnt); 401 } 402 403 static inline struct xt_counters * 404 xt_get_this_cpu_counter(struct xt_counters *cnt) 405 { 406 if (nr_cpu_ids > 1) 407 return this_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt); 408 409 return cnt; 410 } 411 412 static inline struct xt_counters * 413 xt_get_per_cpu_counter(struct xt_counters *cnt, unsigned int cpu) 414 { 415 if (nr_cpu_ids > 1) 416 return per_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt, cpu); 417 418 return cnt; 419 } 420 421 struct nf_hook_ops *xt_hook_ops_alloc(const struct xt_table *, nf_hookfn *); 422 423 #ifdef CONFIG_COMPAT 424 #include <net/compat.h> 425 426 struct compat_xt_entry_match { 427 union { 428 struct { 429 u_int16_t match_size; 430 char name[XT_FUNCTION_MAXNAMELEN - 1]; 431 u_int8_t revision; 432 } user; 433 struct { 434 u_int16_t match_size; 435 compat_uptr_t match; 436 } kernel; 437 u_int16_t match_size; 438 } u; 439 unsigned char data[0]; 440 }; 441 442 struct compat_xt_entry_target { 443 union { 444 struct { 445 u_int16_t target_size; 446 char name[XT_FUNCTION_MAXNAMELEN - 1]; 447 u_int8_t revision; 448 } user; 449 struct { 450 u_int16_t target_size; 451 compat_uptr_t target; 452 } kernel; 453 u_int16_t target_size; 454 } u; 455 unsigned char data[0]; 456 }; 457 458 /* FIXME: this works only on 32 bit tasks 459 * need to change whole approach in order to calculate align as function of 460 * current task alignment */ 461 462 struct compat_xt_counters { 463 compat_u64 pcnt, bcnt; /* Packet and byte counters */ 464 }; 465 466 struct compat_xt_counters_info { 467 char name[XT_TABLE_MAXNAMELEN]; 468 compat_uint_t num_counters; 469 struct compat_xt_counters counters[0]; 470 }; 471 472 struct _compat_xt_align { 473 __u8 u8; 474 __u16 u16; 475 __u32 u32; 476 compat_u64 u64; 477 }; 478 479 #define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align)) 480 481 void xt_compat_lock(u_int8_t af); 482 void xt_compat_unlock(u_int8_t af); 483 484 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta); 485 void xt_compat_flush_offsets(u_int8_t af); 486 void xt_compat_init_offsets(u_int8_t af, unsigned int number); 487 int xt_compat_calc_jump(u_int8_t af, unsigned int offset); 488 489 int xt_compat_match_offset(const struct xt_match *match); 490 void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, 491 unsigned int *size); 492 int xt_compat_match_to_user(const struct xt_entry_match *m, 493 void __user **dstptr, unsigned int *size); 494 495 int xt_compat_target_offset(const struct xt_target *target); 496 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 497 unsigned int *size); 498 int xt_compat_target_to_user(const struct xt_entry_target *t, 499 void __user **dstptr, unsigned int *size); 500 int xt_compat_check_entry_offsets(const void *base, const char *elems, 501 unsigned int target_offset, 502 unsigned int next_offset); 503 504 #endif /* CONFIG_COMPAT */ 505 #endif /* _X_TABLES_H */ 506
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