1 #ifndef _X_TABLES_H 2 #define _X_TABLES_H 3 #include <linux/kernel.h> 4 #include <linux/types.h> 5 6 #define XT_FUNCTION_MAXNAMELEN 30 7 #define XT_EXTENSION_MAXNAMELEN 29 8 #define XT_TABLE_MAXNAMELEN 32 9 10 struct xt_entry_match { 11 union { 12 struct { 13 __u16 match_size; 14 15 /* Used by userspace */ 16 char name[XT_EXTENSION_MAXNAMELEN]; 17 __u8 revision; 18 } user; 19 struct { 20 __u16 match_size; 21 22 /* Used inside the kernel */ 23 struct xt_match *match; 24 } kernel; 25 26 /* Total length */ 27 __u16 match_size; 28 } u; 29 30 unsigned char data[0]; 31 }; 32 33 struct xt_entry_target { 34 union { 35 struct { 36 __u16 target_size; 37 38 /* Used by userspace */ 39 char name[XT_EXTENSION_MAXNAMELEN]; 40 __u8 revision; 41 } user; 42 struct { 43 __u16 target_size; 44 45 /* Used inside the kernel */ 46 struct xt_target *target; 47 } kernel; 48 49 /* Total length */ 50 __u16 target_size; 51 } u; 52 53 unsigned char data[0]; 54 }; 55 56 #define XT_TARGET_INIT(__name, __size) \ 57 { \ 58 .target.u.user = { \ 59 .target_size = XT_ALIGN(__size), \ 60 .name = __name, \ 61 }, \ 62 } 63 64 struct xt_standard_target { 65 struct xt_entry_target target; 66 int verdict; 67 }; 68 69 struct xt_error_target { 70 struct xt_entry_target target; 71 char errorname[XT_FUNCTION_MAXNAMELEN]; 72 }; 73 74 /* The argument to IPT_SO_GET_REVISION_*. Returns highest revision 75 * kernel supports, if >= revision. */ 76 struct xt_get_revision { 77 char name[XT_EXTENSION_MAXNAMELEN]; 78 __u8 revision; 79 }; 80 81 /* CONTINUE verdict for targets */ 82 #define XT_CONTINUE 0xFFFFFFFF 83 84 /* For standard target */ 85 #define XT_RETURN (-NF_REPEAT - 1) 86 87 /* this is a dummy structure to find out the alignment requirement for a struct 88 * containing all the fundamental data types that are used in ipt_entry, 89 * ip6t_entry and arpt_entry. This sucks, and it is a hack. It will be my 90 * personal pleasure to remove it -HW 91 */ 92 struct _xt_align { 93 __u8 u8; 94 __u16 u16; 95 __u32 u32; 96 __u64 u64; 97 }; 98 99 #define XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _xt_align)) 100 101 /* Standard return verdict, or do jump. */ 102 #define XT_STANDARD_TARGET "" 103 /* Error verdict. */ 104 #define XT_ERROR_TARGET "ERROR" 105 106 #define SET_COUNTER(c,b,p) do { (c).bcnt = (b); (c).pcnt = (p); } while(0) 107 #define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0) 108 109 struct xt_counters { 110 __u64 pcnt, bcnt; /* Packet and byte counters */ 111 }; 112 113 /* The argument to IPT_SO_ADD_COUNTERS. */ 114 struct xt_counters_info { 115 /* Which table. */ 116 char name[XT_TABLE_MAXNAMELEN]; 117 118 unsigned int num_counters; 119 120 /* The counters (actually `number' of these). */ 121 struct xt_counters counters[0]; 122 }; 123 124 #define XT_INV_PROTO 0x40 /* Invert the sense of PROTO. */ 125 126 #ifndef __KERNEL__ 127 /* fn returns 0 to continue iteration */ 128 #define XT_MATCH_ITERATE(type, e, fn, args...) \ 129 ({ \ 130 unsigned int __i; \ 131 int __ret = 0; \ 132 struct xt_entry_match *__m; \ 133 \ 134 for (__i = sizeof(type); \ 135 __i < (e)->target_offset; \ 136 __i += __m->u.match_size) { \ 137 __m = (void *)e + __i; \ 138 \ 139 __ret = fn(__m , ## args); \ 140 if (__ret != 0) \ 141 break; \ 142 } \ 143 __ret; \ 144 }) 145 146 /* fn returns 0 to continue iteration */ 147 #define XT_ENTRY_ITERATE_CONTINUE(type, entries, size, n, fn, args...) \ 148 ({ \ 149 unsigned int __i, __n; \ 150 int __ret = 0; \ 151 type *__entry; \ 152 \ 153 for (__i = 0, __n = 0; __i < (size); \ 154 __i += __entry->next_offset, __n++) { \ 155 __entry = (void *)(entries) + __i; \ 156 if (__n < n) \ 157 continue; \ 158 \ 159 __ret = fn(__entry , ## args); \ 160 if (__ret != 0) \ 161 break; \ 162 } \ 163 __ret; \ 164 }) 165 166 /* fn returns 0 to continue iteration */ 167 #define XT_ENTRY_ITERATE(type, entries, size, fn, args...) \ 168 XT_ENTRY_ITERATE_CONTINUE(type, entries, size, 0, fn, args) 169 170 #endif /* !__KERNEL__ */ 171 172 /* pos is normally a struct ipt_entry/ip6t_entry/etc. */ 173 #define xt_entry_foreach(pos, ehead, esize) \ 174 for ((pos) = (typeof(pos))(ehead); \ 175 (pos) < (typeof(pos))((char *)(ehead) + (esize)); \ 176 (pos) = (typeof(pos))((char *)(pos) + (pos)->next_offset)) 177 178 /* can only be xt_entry_match, so no use of typeof here */ 179 #define xt_ematch_foreach(pos, entry) \ 180 for ((pos) = (struct xt_entry_match *)entry->elems; \ 181 (pos) < (struct xt_entry_match *)((char *)(entry) + \ 182 (entry)->target_offset); \ 183 (pos) = (struct xt_entry_match *)((char *)(pos) + \ 184 (pos)->u.match_size)) 185 186 #ifdef __KERNEL__ 187 188 #include <linux/netdevice.h> 189 190 /** 191 * struct xt_action_param - parameters for matches/targets 192 * 193 * @match: the match extension 194 * @target: the target extension 195 * @matchinfo: per-match data 196 * @targetinfo: per-target data 197 * @in: input netdevice 198 * @out: output netdevice 199 * @fragoff: packet is a fragment, this is the data offset 200 * @thoff: position of transport header relative to skb->data 201 * @hook: hook number given packet came from 202 * @family: Actual NFPROTO_* through which the function is invoked 203 * (helpful when match->family == NFPROTO_UNSPEC) 204 * 205 * Fields written to by extensions: 206 * 207 * @hotdrop: drop packet if we had inspection problems 208 * Network namespace obtainable using dev_net(in/out) 209 */ 210 struct xt_action_param { 211 union { 212 const struct xt_match *match; 213 const struct xt_target *target; 214 }; 215 union { 216 const void *matchinfo, *targinfo; 217 }; 218 const struct net_device *in, *out; 219 int fragoff; 220 unsigned int thoff; 221 unsigned int hooknum; 222 u_int8_t family; 223 bool hotdrop; 224 }; 225 226 /** 227 * struct xt_mtchk_param - parameters for match extensions' 228 * checkentry functions 229 * 230 * @net: network namespace through which the check was invoked 231 * @table: table the rule is tried to be inserted into 232 * @entryinfo: the family-specific rule data 233 * (struct ipt_ip, ip6t_ip, arpt_arp or (note) ebt_entry) 234 * @match: struct xt_match through which this function was invoked 235 * @matchinfo: per-match data 236 * @hook_mask: via which hooks the new rule is reachable 237 * Other fields as above. 238 */ 239 struct xt_mtchk_param { 240 struct net *net; 241 const char *table; 242 const void *entryinfo; 243 const struct xt_match *match; 244 void *matchinfo; 245 unsigned int hook_mask; 246 u_int8_t family; 247 }; 248 249 /** 250 * struct xt_mdtor_param - match destructor parameters 251 * Fields as above. 252 */ 253 struct xt_mtdtor_param { 254 struct net *net; 255 const struct xt_match *match; 256 void *matchinfo; 257 u_int8_t family; 258 }; 259 260 /** 261 * struct xt_tgchk_param - parameters for target extensions' 262 * checkentry functions 263 * 264 * @entryinfo: the family-specific rule data 265 * (struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry) 266 * 267 * Other fields see above. 268 */ 269 struct xt_tgchk_param { 270 struct net *net; 271 const char *table; 272 const void *entryinfo; 273 const struct xt_target *target; 274 void *targinfo; 275 unsigned int hook_mask; 276 u_int8_t family; 277 }; 278 279 /* Target destructor parameters */ 280 struct xt_tgdtor_param { 281 struct net *net; 282 const struct xt_target *target; 283 void *targinfo; 284 u_int8_t family; 285 }; 286 287 struct xt_match { 288 struct list_head list; 289 290 const char name[XT_EXTENSION_MAXNAMELEN]; 291 u_int8_t revision; 292 293 /* Return true or false: return FALSE and set *hotdrop = 1 to 294 force immediate packet drop. */ 295 /* Arguments changed since 2.6.9, as this must now handle 296 non-linear skb, using skb_header_pointer and 297 skb_ip_make_writable. */ 298 bool (*match)(const struct sk_buff *skb, 299 struct xt_action_param *); 300 301 /* Called when user tries to insert an entry of this type. */ 302 int (*checkentry)(const struct xt_mtchk_param *); 303 304 /* Called when entry of this type deleted. */ 305 void (*destroy)(const struct xt_mtdtor_param *); 306 #ifdef CONFIG_COMPAT 307 /* Called when userspace align differs from kernel space one */ 308 void (*compat_from_user)(void *dst, const void *src); 309 int (*compat_to_user)(void __user *dst, const void *src); 310 #endif 311 /* Set this to THIS_MODULE if you are a module, otherwise NULL */ 312 struct module *me; 313 314 const char *table; 315 unsigned int matchsize; 316 #ifdef CONFIG_COMPAT 317 unsigned int compatsize; 318 #endif 319 unsigned int hooks; 320 unsigned short proto; 321 322 unsigned short family; 323 }; 324 325 /* Registration hooks for targets. */ 326 struct xt_target { 327 struct list_head list; 328 329 const char name[XT_EXTENSION_MAXNAMELEN]; 330 u_int8_t revision; 331 332 /* Returns verdict. Argument order changed since 2.6.9, as this 333 must now handle non-linear skbs, using skb_copy_bits and 334 skb_ip_make_writable. */ 335 unsigned int (*target)(struct sk_buff *skb, 336 const struct xt_action_param *); 337 338 /* Called when user tries to insert an entry of this type: 339 hook_mask is a bitmask of hooks from which it can be 340 called. */ 341 /* Should return 0 on success or an error code otherwise (-Exxxx). */ 342 int (*checkentry)(const struct xt_tgchk_param *); 343 344 /* Called when entry of this type deleted. */ 345 void (*destroy)(const struct xt_tgdtor_param *); 346 #ifdef CONFIG_COMPAT 347 /* Called when userspace align differs from kernel space one */ 348 void (*compat_from_user)(void *dst, const void *src); 349 int (*compat_to_user)(void __user *dst, const void *src); 350 #endif 351 /* Set this to THIS_MODULE if you are a module, otherwise NULL */ 352 struct module *me; 353 354 const char *table; 355 unsigned int targetsize; 356 #ifdef CONFIG_COMPAT 357 unsigned int compatsize; 358 #endif 359 unsigned int hooks; 360 unsigned short proto; 361 362 unsigned short family; 363 }; 364 365 /* Furniture shopping... */ 366 struct xt_table { 367 struct list_head list; 368 369 /* What hooks you will enter on */ 370 unsigned int valid_hooks; 371 372 /* Man behind the curtain... */ 373 struct xt_table_info *private; 374 375 /* Set this to THIS_MODULE if you are a module, otherwise NULL */ 376 struct module *me; 377 378 u_int8_t af; /* address/protocol family */ 379 int priority; /* hook order */ 380 381 /* A unique name... */ 382 const char name[XT_TABLE_MAXNAMELEN]; 383 }; 384 385 #include <linux/netfilter_ipv4.h> 386 387 /* The table itself */ 388 struct xt_table_info { 389 /* Size per table */ 390 unsigned int size; 391 /* Number of entries: FIXME. --RR */ 392 unsigned int number; 393 /* Initial number of entries. Needed for module usage count */ 394 unsigned int initial_entries; 395 396 /* Entry points and underflows */ 397 unsigned int hook_entry[NF_INET_NUMHOOKS]; 398 unsigned int underflow[NF_INET_NUMHOOKS]; 399 400 /* 401 * Number of user chains. Since tables cannot have loops, at most 402 * @stacksize jumps (number of user chains) can possibly be made. 403 */ 404 unsigned int stacksize; 405 unsigned int __percpu *stackptr; 406 void ***jumpstack; 407 /* ipt_entry tables: one per CPU */ 408 /* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */ 409 void *entries[1]; 410 }; 411 412 #define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \ 413 + nr_cpu_ids * sizeof(char *)) 414 extern int xt_register_target(struct xt_target *target); 415 extern void xt_unregister_target(struct xt_target *target); 416 extern int xt_register_targets(struct xt_target *target, unsigned int n); 417 extern void xt_unregister_targets(struct xt_target *target, unsigned int n); 418 419 extern int xt_register_match(struct xt_match *target); 420 extern void xt_unregister_match(struct xt_match *target); 421 extern int xt_register_matches(struct xt_match *match, unsigned int n); 422 extern void xt_unregister_matches(struct xt_match *match, unsigned int n); 423 424 extern int xt_check_match(struct xt_mtchk_param *, 425 unsigned int size, u_int8_t proto, bool inv_proto); 426 extern int xt_check_target(struct xt_tgchk_param *, 427 unsigned int size, u_int8_t proto, bool inv_proto); 428 429 extern struct xt_table *xt_register_table(struct net *net, 430 const struct xt_table *table, 431 struct xt_table_info *bootstrap, 432 struct xt_table_info *newinfo); 433 extern void *xt_unregister_table(struct xt_table *table); 434 435 extern struct xt_table_info *xt_replace_table(struct xt_table *table, 436 unsigned int num_counters, 437 struct xt_table_info *newinfo, 438 int *error); 439 440 extern struct xt_match *xt_find_match(u8 af, const char *name, u8 revision); 441 extern struct xt_target *xt_find_target(u8 af, const char *name, u8 revision); 442 extern struct xt_match *xt_request_find_match(u8 af, const char *name, 443 u8 revision); 444 extern struct xt_target *xt_request_find_target(u8 af, const char *name, 445 u8 revision); 446 extern int xt_find_revision(u8 af, const char *name, u8 revision, 447 int target, int *err); 448 449 extern struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, 450 const char *name); 451 extern void xt_table_unlock(struct xt_table *t); 452 453 extern int xt_proto_init(struct net *net, u_int8_t af); 454 extern void xt_proto_fini(struct net *net, u_int8_t af); 455 456 extern struct xt_table_info *xt_alloc_table_info(unsigned int size); 457 extern void xt_free_table_info(struct xt_table_info *info); 458 459 /** 460 * xt_recseq - recursive seqcount for netfilter use 461 * 462 * Packet processing changes the seqcount only if no recursion happened 463 * get_counters() can use read_seqcount_begin()/read_seqcount_retry(), 464 * because we use the normal seqcount convention : 465 * Low order bit set to 1 if a writer is active. 466 */ 467 DECLARE_PER_CPU(seqcount_t, xt_recseq); 468 469 /** 470 * xt_write_recseq_begin - start of a write section 471 * 472 * Begin packet processing : all readers must wait the end 473 * 1) Must be called with preemption disabled 474 * 2) softirqs must be disabled too (or we should use this_cpu_add()) 475 * Returns : 476 * 1 if no recursion on this cpu 477 * 0 if recursion detected 478 */ 479 static inline unsigned int xt_write_recseq_begin(void) 480 { 481 unsigned int addend; 482 483 /* 484 * Low order bit of sequence is set if we already 485 * called xt_write_recseq_begin(). 486 */ 487 addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1; 488 489 /* 490 * This is kind of a write_seqcount_begin(), but addend is 0 or 1 491 * We dont check addend value to avoid a test and conditional jump, 492 * since addend is most likely 1 493 */ 494 __this_cpu_add(xt_recseq.sequence, addend); 495 smp_wmb(); 496 497 return addend; 498 } 499 500 /** 501 * xt_write_recseq_end - end of a write section 502 * @addend: return value from previous xt_write_recseq_begin() 503 * 504 * End packet processing : all readers can proceed 505 * 1) Must be called with preemption disabled 506 * 2) softirqs must be disabled too (or we should use this_cpu_add()) 507 */ 508 static inline void xt_write_recseq_end(unsigned int addend) 509 { 510 /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */ 511 smp_wmb(); 512 __this_cpu_add(xt_recseq.sequence, addend); 513 } 514 515 /* 516 * This helper is performance critical and must be inlined 517 */ 518 static inline unsigned long ifname_compare_aligned(const char *_a, 519 const char *_b, 520 const char *_mask) 521 { 522 const unsigned long *a = (const unsigned long *)_a; 523 const unsigned long *b = (const unsigned long *)_b; 524 const unsigned long *mask = (const unsigned long *)_mask; 525 unsigned long ret; 526 527 ret = (a[0] ^ b[0]) & mask[0]; 528 if (IFNAMSIZ > sizeof(unsigned long)) 529 ret |= (a[1] ^ b[1]) & mask[1]; 530 if (IFNAMSIZ > 2 * sizeof(unsigned long)) 531 ret |= (a[2] ^ b[2]) & mask[2]; 532 if (IFNAMSIZ > 3 * sizeof(unsigned long)) 533 ret |= (a[3] ^ b[3]) & mask[3]; 534 BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); 535 return ret; 536 } 537 538 extern struct nf_hook_ops *xt_hook_link(const struct xt_table *, nf_hookfn *); 539 extern void xt_hook_unlink(const struct xt_table *, struct nf_hook_ops *); 540 541 #ifdef CONFIG_COMPAT 542 #include <net/compat.h> 543 544 struct compat_xt_entry_match { 545 union { 546 struct { 547 u_int16_t match_size; 548 char name[XT_FUNCTION_MAXNAMELEN - 1]; 549 u_int8_t revision; 550 } user; 551 struct { 552 u_int16_t match_size; 553 compat_uptr_t match; 554 } kernel; 555 u_int16_t match_size; 556 } u; 557 unsigned char data[0]; 558 }; 559 560 struct compat_xt_entry_target { 561 union { 562 struct { 563 u_int16_t target_size; 564 char name[XT_FUNCTION_MAXNAMELEN - 1]; 565 u_int8_t revision; 566 } user; 567 struct { 568 u_int16_t target_size; 569 compat_uptr_t target; 570 } kernel; 571 u_int16_t target_size; 572 } u; 573 unsigned char data[0]; 574 }; 575 576 /* FIXME: this works only on 32 bit tasks 577 * need to change whole approach in order to calculate align as function of 578 * current task alignment */ 579 580 struct compat_xt_counters { 581 compat_u64 pcnt, bcnt; /* Packet and byte counters */ 582 }; 583 584 struct compat_xt_counters_info { 585 char name[XT_TABLE_MAXNAMELEN]; 586 compat_uint_t num_counters; 587 struct compat_xt_counters counters[0]; 588 }; 589 590 struct _compat_xt_align { 591 __u8 u8; 592 __u16 u16; 593 __u32 u32; 594 compat_u64 u64; 595 }; 596 597 #define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align)) 598 599 extern void xt_compat_lock(u_int8_t af); 600 extern void xt_compat_unlock(u_int8_t af); 601 602 extern int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta); 603 extern void xt_compat_flush_offsets(u_int8_t af); 604 extern void xt_compat_init_offsets(u_int8_t af, unsigned int number); 605 extern int xt_compat_calc_jump(u_int8_t af, unsigned int offset); 606 607 extern int xt_compat_match_offset(const struct xt_match *match); 608 extern int xt_compat_match_from_user(struct xt_entry_match *m, 609 void **dstptr, unsigned int *size); 610 extern int xt_compat_match_to_user(const struct xt_entry_match *m, 611 void __user **dstptr, unsigned int *size); 612 613 extern int xt_compat_target_offset(const struct xt_target *target); 614 extern void xt_compat_target_from_user(struct xt_entry_target *t, 615 void **dstptr, unsigned int *size); 616 extern int xt_compat_target_to_user(const struct xt_entry_target *t, 617 void __user **dstptr, unsigned int *size); 618 619 #endif /* CONFIG_COMPAT */ 620 #endif /* __KERNEL__ */ 621 622 #endif /* _X_TABLES_H */ 623