1 /*- 2 * Copyright (c) 2002 Luigi Rizzo, Universita` di Pisa 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * $FreeBSD$ 26 */ 27 28 #ifndef _IPFW2_H 29 #define _IPFW2_H 30 #define IPFW2 1 31 32 /* 33 * The kernel representation of ipfw rules is made of a list of 34 * 'instructions' (for all practical purposes equivalent to BPF 35 * instructions), which specify which fields of the packet 36 * (or its metadata) should be analysed. 37 * 38 * Each instruction is stored in a structure which begins with 39 * "ipfw_insn", and can contain extra fields depending on the 40 * instruction type (listed below). 41 * Note that the code is written so that individual instructions 42 * have a size which is a multiple of 32 bits. This means that, if 43 * such structures contain pointers or other 64-bit entities, 44 * (there is just one instance now) they may end up unaligned on 45 * 64-bit architectures, so the must be handled with care. 46 * 47 * "enum ipfw_opcodes" are the opcodes supported. We can have up 48 * to 256 different opcodes. When adding new opcodes, they should 49 * be appended to the end of the opcode list before O_LAST_OPCODE, 50 * this will prevent the ABI from being broken, otherwise users 51 * will have to recompile ipfw(8) when they update the kernel. 52 */ 53 54 enum ipfw_opcodes { /* arguments (4 byte each) */ 55 O_NOP, 56 57 O_IP_SRC, /* u32 = IP */ 58 O_IP_SRC_MASK, /* ip = IP/mask */ 59 O_IP_SRC_ME, /* none */ 60 O_IP_SRC_SET, /* u32=base, arg1=len, bitmap */ 61 62 O_IP_DST, /* u32 = IP */ 63 O_IP_DST_MASK, /* ip = IP/mask */ 64 O_IP_DST_ME, /* none */ 65 O_IP_DST_SET, /* u32=base, arg1=len, bitmap */ 66 67 O_IP_SRCPORT, /* (n)port list:mask 4 byte ea */ 68 O_IP_DSTPORT, /* (n)port list:mask 4 byte ea */ 69 O_PROTO, /* arg1=protocol */ 70 71 O_MACADDR2, /* 2 mac addr:mask */ 72 O_MAC_TYPE, /* same as srcport */ 73 74 O_LAYER2, /* none */ 75 O_IN, /* none */ 76 O_FRAG, /* none */ 77 78 O_RECV, /* none */ 79 O_XMIT, /* none */ 80 O_VIA, /* none */ 81 82 O_IPOPT, /* arg1 = 2*u8 bitmap */ 83 O_IPLEN, /* arg1 = len */ 84 O_IPID, /* arg1 = id */ 85 86 O_IPTOS, /* arg1 = id */ 87 O_IPPRECEDENCE, /* arg1 = precedence << 5 */ 88 O_IPTTL, /* arg1 = TTL */ 89 90 O_IPVER, /* arg1 = version */ 91 O_UID, /* u32 = id */ 92 O_GID, /* u32 = id */ 93 O_ESTAB, /* none (tcp established) */ 94 O_TCPFLAGS, /* arg1 = 2*u8 bitmap */ 95 O_TCPWIN, /* arg1 = desired win */ 96 O_TCPSEQ, /* u32 = desired seq. */ 97 O_TCPACK, /* u32 = desired seq. */ 98 O_ICMPTYPE, /* u32 = icmp bitmap */ 99 O_TCPOPTS, /* arg1 = 2*u8 bitmap */ 100 101 O_VERREVPATH, /* none */ 102 O_VERSRCREACH, /* none */ 103 104 O_PROBE_STATE, /* none */ 105 O_KEEP_STATE, /* none */ 106 O_LIMIT, /* ipfw_insn_limit */ 107 O_LIMIT_PARENT, /* dyn_type, not an opcode. */ 108 109 /* 110 * These are really 'actions'. 111 */ 112 113 O_LOG, /* ipfw_insn_log */ 114 O_PROB, /* u32 = match probability */ 115 116 O_CHECK_STATE, /* none */ 117 O_ACCEPT, /* none */ 118 O_DENY, /* none */ 119 O_REJECT, /* arg1=icmp arg (same as deny) */ 120 O_COUNT, /* none */ 121 O_SKIPTO, /* arg1=next rule number */ 122 O_PIPE, /* arg1=pipe number */ 123 O_QUEUE, /* arg1=queue number */ 124 O_DIVERT, /* arg1=port number */ 125 O_TEE, /* arg1=port number */ 126 O_FORWARD_IP, /* fwd sockaddr */ 127 O_FORWARD_MAC, /* fwd mac */ 128 129 /* 130 * More opcodes. 131 */ 132 O_IPSEC, /* has ipsec history */ 133 O_IP_SRC_LOOKUP, /* arg1=table number, u32=value */ 134 O_IP_DST_LOOKUP, /* arg1=table number, u32=value */ 135 O_ANTISPOOF, /* none */ 136 O_JAIL, /* u32 = id */ 137 O_ALTQ, /* u32 = altq classif. qid */ 138 O_DIVERTED, /* arg1=bitmap (1:loop, 2:out) */ 139 O_TCPDATALEN, /* arg1 = tcp data len */ 140 O_IP6_SRC, /* address without mask */ 141 O_IP6_SRC_ME, /* my addresses */ 142 O_IP6_SRC_MASK, /* address with the mask */ 143 O_IP6_DST, 144 O_IP6_DST_ME, 145 O_IP6_DST_MASK, 146 O_FLOW6ID, /* for flow id tag in the ipv6 pkt */ 147 O_ICMP6TYPE, /* icmp6 packet type filtering */ 148 O_EXT_HDR, /* filtering for ipv6 extension header */ 149 O_IP6, 150 151 /* 152 * actions for ng_ipfw 153 */ 154 O_NETGRAPH, /* send to ng_ipfw */ 155 O_NGTEE, /* copy to ng_ipfw */ 156 157 O_LAST_OPCODE /* not an opcode! */ 158 }; 159 160 /* 161 * The extension header are filtered only for presence using a bit 162 * vector with a flag for each header. 163 */ 164 #define EXT_FRAGMENT 0x1 165 #define EXT_HOPOPTS 0x2 166 #define EXT_ROUTING 0x4 167 #define EXT_AH 0x8 168 #define EXT_ESP 0x10 169 170 /* 171 * Template for instructions. 172 * 173 * ipfw_insn is used for all instructions which require no operands, 174 * a single 16-bit value (arg1), or a couple of 8-bit values. 175 * 176 * For other instructions which require different/larger arguments 177 * we have derived structures, ipfw_insn_*. 178 * 179 * The size of the instruction (in 32-bit words) is in the low 180 * 6 bits of "len". The 2 remaining bits are used to implement 181 * NOT and OR on individual instructions. Given a type, you can 182 * compute the length to be put in "len" using F_INSN_SIZE(t) 183 * 184 * F_NOT negates the match result of the instruction. 185 * 186 * F_OR is used to build or blocks. By default, instructions 187 * are evaluated as part of a logical AND. An "or" block 188 * { X or Y or Z } contains F_OR set in all but the last 189 * instruction of the block. A match will cause the code 190 * to skip past the last instruction of the block. 191 * 192 * NOTA BENE: in a couple of places we assume that 193 * sizeof(ipfw_insn) == sizeof(u_int32_t) 194 * this needs to be fixed. 195 * 196 */ 197 typedef struct _ipfw_insn { /* template for instructions */ 198 enum ipfw_opcodes opcode:8; 199 u_int8_t len; /* numer of 32-byte words */ 200 #define F_NOT 0x80 201 #define F_OR 0x40 202 #define F_LEN_MASK 0x3f 203 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK) 204 205 u_int16_t arg1; 206 } ipfw_insn; 207 208 /* 209 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of 210 * a given type. 211 */ 212 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t)) 213 214 /* 215 * This is used to store an array of 16-bit entries (ports etc.) 216 */ 217 typedef struct _ipfw_insn_u16 { 218 ipfw_insn o; 219 u_int16_t ports[2]; /* there may be more */ 220 } ipfw_insn_u16; 221 222 /* 223 * This is used to store an array of 32-bit entries 224 * (uid, single IPv4 addresses etc.) 225 */ 226 typedef struct _ipfw_insn_u32 { 227 ipfw_insn o; 228 u_int32_t d[1]; /* one or more */ 229 } ipfw_insn_u32; 230 231 /* 232 * This is used to store IP addr-mask pairs. 233 */ 234 typedef struct _ipfw_insn_ip { 235 ipfw_insn o; 236 struct in_addr addr; 237 struct in_addr mask; 238 } ipfw_insn_ip; 239 240 /* 241 * This is used to forward to a given address (ip). 242 */ 243 typedef struct _ipfw_insn_sa { 244 ipfw_insn o; 245 struct sockaddr_in sa; 246 } ipfw_insn_sa; 247 248 /* 249 * This is used for MAC addr-mask pairs. 250 */ 251 typedef struct _ipfw_insn_mac { 252 ipfw_insn o; 253 u_char addr[12]; /* dst[6] + src[6] */ 254 u_char mask[12]; /* dst[6] + src[6] */ 255 } ipfw_insn_mac; 256 257 /* 258 * This is used for interface match rules (recv xx, xmit xx). 259 */ 260 typedef struct _ipfw_insn_if { 261 ipfw_insn o; 262 union { 263 struct in_addr ip; 264 int glob; 265 } p; 266 char name[IFNAMSIZ]; 267 } ipfw_insn_if; 268 269 /* 270 * This is used for pipe and queue actions, which need to store 271 * a single pointer (which can have different size on different 272 * architectures. 273 * Note that, because of previous instructions, pipe_ptr might 274 * be unaligned in the overall structure, so it needs to be 275 * manipulated with care. 276 */ 277 typedef struct _ipfw_insn_pipe { 278 ipfw_insn o; 279 void *pipe_ptr; /* XXX */ 280 } ipfw_insn_pipe; 281 282 /* 283 * This is used for storing an altq queue id number. 284 */ 285 typedef struct _ipfw_insn_altq { 286 ipfw_insn o; 287 u_int32_t qid; 288 } ipfw_insn_altq; 289 290 /* 291 * This is used for limit rules. 292 */ 293 typedef struct _ipfw_insn_limit { 294 ipfw_insn o; 295 u_int8_t _pad; 296 u_int8_t limit_mask; /* combination of DYN_* below */ 297 #define DYN_SRC_ADDR 0x1 298 #define DYN_SRC_PORT 0x2 299 #define DYN_DST_ADDR 0x4 300 #define DYN_DST_PORT 0x8 301 302 u_int16_t conn_limit; 303 } ipfw_insn_limit; 304 305 /* 306 * This is used for log instructions. 307 */ 308 typedef struct _ipfw_insn_log { 309 ipfw_insn o; 310 u_int32_t max_log; /* how many do we log -- 0 = all */ 311 u_int32_t log_left; /* how many left to log */ 312 } ipfw_insn_log; 313 314 /* Apply ipv6 mask on ipv6 addr */ 315 #define APPLY_MASK(addr,mask) \ 316 (addr)->__u6_addr.__u6_addr32[0] &= (mask)->__u6_addr.__u6_addr32[0]; \ 317 (addr)->__u6_addr.__u6_addr32[1] &= (mask)->__u6_addr.__u6_addr32[1]; \ 318 (addr)->__u6_addr.__u6_addr32[2] &= (mask)->__u6_addr.__u6_addr32[2]; \ 319 (addr)->__u6_addr.__u6_addr32[3] &= (mask)->__u6_addr.__u6_addr32[3]; 320 321 /* Structure for ipv6 */ 322 typedef struct _ipfw_insn_ip6 { 323 ipfw_insn o; 324 struct in6_addr addr6; 325 struct in6_addr mask6; 326 } ipfw_insn_ip6; 327 328 /* Used to support icmp6 types */ 329 typedef struct _ipfw_insn_icmp6 { 330 ipfw_insn o; 331 uint32_t d[7]; /* XXX This number si related to the netinet/icmp6.h 332 * define ICMP6_MAXTYPE 333 * as follows: n = ICMP6_MAXTYPE/32 + 1 334 * Actually is 203 335 */ 336 } ipfw_insn_icmp6; 337 338 /* 339 * Here we have the structure representing an ipfw rule. 340 * 341 * It starts with a general area (with link fields and counters) 342 * followed by an array of one or more instructions, which the code 343 * accesses as an array of 32-bit values. 344 * 345 * Given a rule pointer r: 346 * 347 * r->cmd is the start of the first instruction. 348 * ACTION_PTR(r) is the start of the first action (things to do 349 * once a rule matched). 350 * 351 * When assembling instruction, remember the following: 352 * 353 * + if a rule has a "keep-state" (or "limit") option, then the 354 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE 355 * + if a rule has a "log" option, then the first action 356 * (at ACTION_PTR(r)) MUST be O_LOG 357 * + if a rule has an "altq" option, it comes after "log" 358 * 359 * NOTE: we use a simple linked list of rules because we never need 360 * to delete a rule without scanning the list. We do not use 361 * queue(3) macros for portability and readability. 362 */ 363 364 struct ip_fw { 365 struct ip_fw *next; /* linked list of rules */ 366 struct ip_fw *next_rule; /* ptr to next [skipto] rule */ 367 /* 'next_rule' is used to pass up 'set_disable' status */ 368 369 u_int16_t act_ofs; /* offset of action in 32-bit units */ 370 u_int16_t cmd_len; /* # of 32-bit words in cmd */ 371 u_int16_t rulenum; /* rule number */ 372 u_int8_t set; /* rule set (0..31) */ 373 #define RESVD_SET 31 /* set for default and persistent rules */ 374 u_int8_t _pad; /* padding */ 375 376 /* These fields are present in all rules. */ 377 u_int64_t pcnt; /* Packet counter */ 378 u_int64_t bcnt; /* Byte counter */ 379 u_int32_t timestamp; /* tv_sec of last match */ 380 381 ipfw_insn cmd[1]; /* storage for commands */ 382 }; 383 384 #define ACTION_PTR(rule) \ 385 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) ) 386 387 #define RULESIZE(rule) (sizeof(struct ip_fw) + \ 388 ((struct ip_fw *)(rule))->cmd_len * 4 - 4) 389 390 /* 391 * This structure is used as a flow mask and a flow id for various 392 * parts of the code. 393 */ 394 struct ipfw_flow_id { 395 u_int32_t dst_ip; 396 u_int32_t src_ip; 397 u_int16_t dst_port; 398 u_int16_t src_port; 399 u_int8_t proto; 400 u_int8_t flags; /* protocol-specific flags */ 401 uint8_t addr_type; /* 4 = ipv4, 6 = ipv6, 1=ether ? */ 402 struct in6_addr dst_ip6; /* could also store MAC addr! */ 403 struct in6_addr src_ip6; 404 u_int32_t flow_id6; 405 }; 406 407 #define IS_IP6_FLOW_ID(id) ((id)->addr_type == 6) 408 409 /* 410 * Dynamic ipfw rule. 411 */ 412 typedef struct _ipfw_dyn_rule ipfw_dyn_rule; 413 414 struct _ipfw_dyn_rule { 415 ipfw_dyn_rule *next; /* linked list of rules. */ 416 struct ip_fw *rule; /* pointer to rule */ 417 /* 'rule' is used to pass up the rule number (from the parent) */ 418 419 ipfw_dyn_rule *parent; /* pointer to parent rule */ 420 u_int64_t pcnt; /* packet match counter */ 421 u_int64_t bcnt; /* byte match counter */ 422 struct ipfw_flow_id id; /* (masked) flow id */ 423 u_int32_t expire; /* expire time */ 424 u_int32_t bucket; /* which bucket in hash table */ 425 u_int32_t state; /* state of this rule (typically a 426 * combination of TCP flags) 427 */ 428 u_int32_t ack_fwd; /* most recent ACKs in forward */ 429 u_int32_t ack_rev; /* and reverse directions (used */ 430 /* to generate keepalives) */ 431 u_int16_t dyn_type; /* rule type */ 432 u_int16_t count; /* refcount */ 433 }; 434 435 /* 436 * Definitions for IP option names. 437 */ 438 #define IP_FW_IPOPT_LSRR 0x01 439 #define IP_FW_IPOPT_SSRR 0x02 440 #define IP_FW_IPOPT_RR 0x04 441 #define IP_FW_IPOPT_TS 0x08 442 443 /* 444 * Definitions for TCP option names. 445 */ 446 #define IP_FW_TCPOPT_MSS 0x01 447 #define IP_FW_TCPOPT_WINDOW 0x02 448 #define IP_FW_TCPOPT_SACK 0x04 449 #define IP_FW_TCPOPT_TS 0x08 450 #define IP_FW_TCPOPT_CC 0x10 451 452 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */ 453 454 /* 455 * These are used for lookup tables. 456 */ 457 typedef struct _ipfw_table_entry { 458 in_addr_t addr; /* network address */ 459 u_int32_t value; /* value */ 460 u_int16_t tbl; /* table number */ 461 u_int8_t masklen; /* mask length */ 462 } ipfw_table_entry; 463 464 typedef struct _ipfw_table { 465 u_int32_t size; /* size of entries in bytes */ 466 u_int32_t cnt; /* # of entries */ 467 u_int16_t tbl; /* table number */ 468 ipfw_table_entry ent[0]; /* entries */ 469 } ipfw_table; 470 471 /* 472 * Main firewall chains definitions and global var's definitions. 473 */ 474 #ifdef _KERNEL 475 476 /* Return values from ipfw_chk() */ 477 enum { 478 IP_FW_PASS = 0, 479 IP_FW_DENY, 480 IP_FW_DIVERT, 481 IP_FW_TEE, 482 IP_FW_DUMMYNET, 483 IP_FW_NETGRAPH, 484 IP_FW_NGTEE, 485 }; 486 487 /* flags for divert mtag */ 488 #define IP_FW_DIVERT_LOOPBACK_FLAG 0x00080000 489 #define IP_FW_DIVERT_OUTPUT_FLAG 0x00100000 490 491 /* 492 * Structure for collecting parameters to dummynet for ip6_output forwarding 493 */ 494 struct _ip6dn_args { 495 struct ip6_pktopts *opt_or; 496 struct route_in6 ro_or; 497 int flags_or; 498 struct ip6_moptions *im6o_or; 499 struct ifnet *origifp_or; 500 struct ifnet *ifp_or; 501 struct sockaddr_in6 dst_or; 502 u_long mtu_or; 503 struct route_in6 ro_pmtu_or; 504 }; 505 506 /* 507 * Arguments for calling ipfw_chk() and dummynet_io(). We put them 508 * all into a structure because this way it is easier and more 509 * efficient to pass variables around and extend the interface. 510 */ 511 struct ip_fw_args { 512 struct mbuf *m; /* the mbuf chain */ 513 struct ifnet *oif; /* output interface */ 514 struct sockaddr_in *next_hop; /* forward address */ 515 struct ip_fw *rule; /* matching rule */ 516 struct ether_header *eh; /* for bridged packets */ 517 518 int flags; /* for dummynet */ 519 520 struct ipfw_flow_id f_id; /* grabbed from IP header */ 521 u_int32_t cookie; /* a cookie depending on rule action */ 522 struct inpcb *inp; 523 524 struct _ip6dn_args dummypar; /* dummynet->ip6_output */ 525 }; 526 527 /* 528 * Function definitions. 529 */ 530 531 /* Firewall hooks */ 532 struct sockopt; 533 struct dn_flow_set; 534 535 int ipfw_check_in(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 536 int ipfw_check_out(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 537 538 int ipfw_chk(struct ip_fw_args *); 539 540 int ipfw_init(void); 541 void ipfw_destroy(void); 542 543 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */ 544 545 typedef int ip_fw_ctl_t(struct sockopt *); 546 extern ip_fw_ctl_t *ip_fw_ctl_ptr; 547 extern int fw_one_pass; 548 extern int fw_enable; 549 550 /* For kernel ipfw_ether and ipfw_bridge. */ 551 typedef int ip_fw_chk_t(struct ip_fw_args *args); 552 extern ip_fw_chk_t *ip_fw_chk_ptr; 553 #define IPFW_LOADED (ip_fw_chk_ptr != NULL) 554 555 #endif /* _KERNEL */ 556 #endif /* _IPFW2_H */ 557