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 /* A unique name... */ 204 const char name[XT_TABLE_MAXNAMELEN]; 205 }; 206 207 #include <linux/netfilter_ipv4.h> 208 209 /* The table itself */ 210 struct xt_table_info { 211 /* Size per table */ 212 unsigned int size; 213 /* Number of entries: FIXME. --RR */ 214 unsigned int number; 215 /* Initial number of entries. Needed for module usage count */ 216 unsigned int initial_entries; 217 218 /* Entry points and underflows */ 219 unsigned int hook_entry[NF_INET_NUMHOOKS]; 220 unsigned int underflow[NF_INET_NUMHOOKS]; 221 222 /* 223 * Number of user chains. Since tables cannot have loops, at most 224 * @stacksize jumps (number of user chains) can possibly be made. 225 */ 226 unsigned int stacksize; 227 void ***jumpstack; 228 229 unsigned char entries[0] __aligned(8); 230 }; 231 232 int xt_register_target(struct xt_target *target); 233 void xt_unregister_target(struct xt_target *target); 234 int xt_register_targets(struct xt_target *target, unsigned int n); 235 void xt_unregister_targets(struct xt_target *target, unsigned int n); 236 237 int xt_register_match(struct xt_match *target); 238 void xt_unregister_match(struct xt_match *target); 239 int xt_register_matches(struct xt_match *match, unsigned int n); 240 void xt_unregister_matches(struct xt_match *match, unsigned int n); 241 242 int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto, 243 bool inv_proto); 244 int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto, 245 bool inv_proto); 246 247 struct xt_table *xt_register_table(struct net *net, 248 const struct xt_table *table, 249 struct xt_table_info *bootstrap, 250 struct xt_table_info *newinfo); 251 void *xt_unregister_table(struct xt_table *table); 252 253 struct xt_table_info *xt_replace_table(struct xt_table *table, 254 unsigned int num_counters, 255 struct xt_table_info *newinfo, 256 int *error); 257 258 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision); 259 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision); 260 struct xt_match *xt_request_find_match(u8 af, const char *name, u8 revision); 261 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision); 262 int xt_find_revision(u8 af, const char *name, u8 revision, int target, 263 int *err); 264 265 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, 266 const char *name); 267 void xt_table_unlock(struct xt_table *t); 268 269 int xt_proto_init(struct net *net, u_int8_t af); 270 void xt_proto_fini(struct net *net, u_int8_t af); 271 272 struct xt_table_info *xt_alloc_table_info(unsigned int size); 273 void xt_free_table_info(struct xt_table_info *info); 274 275 /** 276 * xt_recseq - recursive seqcount for netfilter use 277 * 278 * Packet processing changes the seqcount only if no recursion happened 279 * get_counters() can use read_seqcount_begin()/read_seqcount_retry(), 280 * because we use the normal seqcount convention : 281 * Low order bit set to 1 if a writer is active. 282 */ 283 DECLARE_PER_CPU(seqcount_t, xt_recseq); 284 285 /* xt_tee_enabled - true if x_tables needs to handle reentrancy 286 * 287 * Enabled if current ip(6)tables ruleset has at least one -j TEE rule. 288 */ 289 extern struct static_key xt_tee_enabled; 290 291 /** 292 * xt_write_recseq_begin - start of a write section 293 * 294 * Begin packet processing : all readers must wait the end 295 * 1) Must be called with preemption disabled 296 * 2) softirqs must be disabled too (or we should use this_cpu_add()) 297 * Returns : 298 * 1 if no recursion on this cpu 299 * 0 if recursion detected 300 */ 301 static inline unsigned int xt_write_recseq_begin(void) 302 { 303 unsigned int addend; 304 305 /* 306 * Low order bit of sequence is set if we already 307 * called xt_write_recseq_begin(). 308 */ 309 addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1; 310 311 /* 312 * This is kind of a write_seqcount_begin(), but addend is 0 or 1 313 * We dont check addend value to avoid a test and conditional jump, 314 * since addend is most likely 1 315 */ 316 __this_cpu_add(xt_recseq.sequence, addend); 317 smp_wmb(); 318 319 return addend; 320 } 321 322 /** 323 * xt_write_recseq_end - end of a write section 324 * @addend: return value from previous xt_write_recseq_begin() 325 * 326 * End packet processing : all readers can proceed 327 * 1) Must be called with preemption disabled 328 * 2) softirqs must be disabled too (or we should use this_cpu_add()) 329 */ 330 static inline void xt_write_recseq_end(unsigned int addend) 331 { 332 /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */ 333 smp_wmb(); 334 __this_cpu_add(xt_recseq.sequence, addend); 335 } 336 337 /* 338 * This helper is performance critical and must be inlined 339 */ 340 static inline unsigned long ifname_compare_aligned(const char *_a, 341 const char *_b, 342 const char *_mask) 343 { 344 const unsigned long *a = (const unsigned long *)_a; 345 const unsigned long *b = (const unsigned long *)_b; 346 const unsigned long *mask = (const unsigned long *)_mask; 347 unsigned long ret; 348 349 ret = (a[0] ^ b[0]) & mask[0]; 350 if (IFNAMSIZ > sizeof(unsigned long)) 351 ret |= (a[1] ^ b[1]) & mask[1]; 352 if (IFNAMSIZ > 2 * sizeof(unsigned long)) 353 ret |= (a[2] ^ b[2]) & mask[2]; 354 if (IFNAMSIZ > 3 * sizeof(unsigned long)) 355 ret |= (a[3] ^ b[3]) & mask[3]; 356 BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); 357 return ret; 358 } 359 360 361 /* On SMP, ip(6)t_entry->counters.pcnt holds address of the 362 * real (percpu) counter. On !SMP, its just the packet count, 363 * so nothing needs to be done there. 364 * 365 * xt_percpu_counter_alloc returns the address of the percpu 366 * counter, or 0 on !SMP. We force an alignment of 16 bytes 367 * so that bytes/packets share a common cache line. 368 * 369 * Hence caller must use IS_ERR_VALUE to check for error, this 370 * allows us to return 0 for single core systems without forcing 371 * callers to deal with SMP vs. NONSMP issues. 372 */ 373 static inline u64 xt_percpu_counter_alloc(void) 374 { 375 if (nr_cpu_ids > 1) { 376 void __percpu *res = __alloc_percpu(sizeof(struct xt_counters), 377 sizeof(struct xt_counters)); 378 379 if (res == NULL) 380 return (u64) -ENOMEM; 381 382 return (u64) (__force unsigned long) res; 383 } 384 385 return 0; 386 } 387 static inline void xt_percpu_counter_free(u64 pcnt) 388 { 389 if (nr_cpu_ids > 1) 390 free_percpu((void __percpu *) (unsigned long) pcnt); 391 } 392 393 static inline struct xt_counters * 394 xt_get_this_cpu_counter(struct xt_counters *cnt) 395 { 396 if (nr_cpu_ids > 1) 397 return this_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt); 398 399 return cnt; 400 } 401 402 static inline struct xt_counters * 403 xt_get_per_cpu_counter(struct xt_counters *cnt, unsigned int cpu) 404 { 405 if (nr_cpu_ids > 1) 406 return per_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt, cpu); 407 408 return cnt; 409 } 410 411 struct nf_hook_ops *xt_hook_link(const struct xt_table *, nf_hookfn *); 412 void xt_hook_unlink(const struct xt_table *, struct nf_hook_ops *); 413 414 #ifdef CONFIG_COMPAT 415 #include <net/compat.h> 416 417 struct compat_xt_entry_match { 418 union { 419 struct { 420 u_int16_t match_size; 421 char name[XT_FUNCTION_MAXNAMELEN - 1]; 422 u_int8_t revision; 423 } user; 424 struct { 425 u_int16_t match_size; 426 compat_uptr_t match; 427 } kernel; 428 u_int16_t match_size; 429 } u; 430 unsigned char data[0]; 431 }; 432 433 struct compat_xt_entry_target { 434 union { 435 struct { 436 u_int16_t target_size; 437 char name[XT_FUNCTION_MAXNAMELEN - 1]; 438 u_int8_t revision; 439 } user; 440 struct { 441 u_int16_t target_size; 442 compat_uptr_t target; 443 } kernel; 444 u_int16_t target_size; 445 } u; 446 unsigned char data[0]; 447 }; 448 449 /* FIXME: this works only on 32 bit tasks 450 * need to change whole approach in order to calculate align as function of 451 * current task alignment */ 452 453 struct compat_xt_counters { 454 compat_u64 pcnt, bcnt; /* Packet and byte counters */ 455 }; 456 457 struct compat_xt_counters_info { 458 char name[XT_TABLE_MAXNAMELEN]; 459 compat_uint_t num_counters; 460 struct compat_xt_counters counters[0]; 461 }; 462 463 struct _compat_xt_align { 464 __u8 u8; 465 __u16 u16; 466 __u32 u32; 467 compat_u64 u64; 468 }; 469 470 #define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align)) 471 472 void xt_compat_lock(u_int8_t af); 473 void xt_compat_unlock(u_int8_t af); 474 475 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta); 476 void xt_compat_flush_offsets(u_int8_t af); 477 void xt_compat_init_offsets(u_int8_t af, unsigned int number); 478 int xt_compat_calc_jump(u_int8_t af, unsigned int offset); 479 480 int xt_compat_match_offset(const struct xt_match *match); 481 int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, 482 unsigned int *size); 483 int xt_compat_match_to_user(const struct xt_entry_match *m, 484 void __user **dstptr, unsigned int *size); 485 486 int xt_compat_target_offset(const struct xt_target *target); 487 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 488 unsigned int *size); 489 int xt_compat_target_to_user(const struct xt_entry_target *t, 490 void __user **dstptr, unsigned int *size); 491 492 #endif /* CONFIG_COMPAT */ 493 #endif /* _X_TABLES_H */ 494