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 31 /* 32 * The kernel representation of ipfw rules is made of a list of 33 * 'instructions' (for all practical purposes equivalent to BPF 34 * instructions), which specify which fields of the packet 35 * (or its metadata) should be analysed. 36 * 37 * Each instruction is stored in a structure which begins with 38 * "ipfw_insn", and can contain extra fields depending on the 39 * instruction type (listed below). 40 * Note that the code is written so that individual instructions 41 * have a size which is a multiple of 32 bits. This means that, if 42 * such structures contain pointers or other 64-bit entities, 43 * (there is just one instance now) they may end up unaligned on 44 * 64-bit architectures, so the must be handled with care. 45 * 46 * "enum ipfw_opcodes" are the opcodes supported. We can have up 47 * to 256 different opcodes. When adding new opcodes, they should 48 * be appended to the end of the opcode list before O_LAST_OPCODE, 49 * this will prevent the ABI from being broken, otherwise users 50 * will have to recompile ipfw(8) when they update the kernel. 51 */ 52 53 enum ipfw_opcodes { /* arguments (4 byte each) */ 54 O_NOP, 55 56 O_IP_SRC, /* u32 = IP */ 57 O_IP_SRC_MASK, /* ip = IP/mask */ 58 O_IP_SRC_ME, /* none */ 59 O_IP_SRC_SET, /* u32=base, arg1=len, bitmap */ 60 61 O_IP_DST, /* u32 = IP */ 62 O_IP_DST_MASK, /* ip = IP/mask */ 63 O_IP_DST_ME, /* none */ 64 O_IP_DST_SET, /* u32=base, arg1=len, bitmap */ 65 66 O_IP_SRCPORT, /* (n)port list:mask 4 byte ea */ 67 O_IP_DSTPORT, /* (n)port list:mask 4 byte ea */ 68 O_PROTO, /* arg1=protocol */ 69 70 O_MACADDR2, /* 2 mac addr:mask */ 71 O_MAC_TYPE, /* same as srcport */ 72 73 O_LAYER2, /* none */ 74 O_IN, /* none */ 75 O_FRAG, /* none */ 76 77 O_RECV, /* none */ 78 O_XMIT, /* none */ 79 O_VIA, /* none */ 80 81 O_IPOPT, /* arg1 = 2*u8 bitmap */ 82 O_IPLEN, /* arg1 = len */ 83 O_IPID, /* arg1 = id */ 84 85 O_IPTOS, /* arg1 = id */ 86 O_IPPRECEDENCE, /* arg1 = precedence << 5 */ 87 O_IPTTL, /* arg1 = TTL */ 88 89 O_IPVER, /* arg1 = version */ 90 O_UID, /* u32 = id */ 91 O_GID, /* u32 = id */ 92 O_ESTAB, /* none (tcp established) */ 93 O_TCPFLAGS, /* arg1 = 2*u8 bitmap */ 94 O_TCPWIN, /* arg1 = desired win */ 95 O_TCPSEQ, /* u32 = desired seq. */ 96 O_TCPACK, /* u32 = desired seq. */ 97 O_ICMPTYPE, /* u32 = icmp bitmap */ 98 O_TCPOPTS, /* arg1 = 2*u8 bitmap */ 99 100 O_VERREVPATH, /* none */ 101 O_VERSRCREACH, /* none */ 102 103 O_PROBE_STATE, /* none */ 104 O_KEEP_STATE, /* none */ 105 O_LIMIT, /* ipfw_insn_limit */ 106 O_LIMIT_PARENT, /* dyn_type, not an opcode. */ 107 108 /* 109 * These are really 'actions'. 110 */ 111 112 O_LOG, /* ipfw_insn_log */ 113 O_PROB, /* u32 = match probability */ 114 115 O_CHECK_STATE, /* none */ 116 O_ACCEPT, /* none */ 117 O_DENY, /* none */ 118 O_REJECT, /* arg1=icmp arg (same as deny) */ 119 O_COUNT, /* none */ 120 O_SKIPTO, /* arg1=next rule number */ 121 O_PIPE, /* arg1=pipe number */ 122 O_QUEUE, /* arg1=queue number */ 123 O_DIVERT, /* arg1=port number */ 124 O_TEE, /* arg1=port number */ 125 O_FORWARD_IP, /* fwd sockaddr */ 126 O_FORWARD_MAC, /* fwd mac */ 127 128 /* 129 * More opcodes. 130 */ 131 O_IPSEC, /* has ipsec history */ 132 O_IP_SRC_LOOKUP, /* arg1=table number, u32=value */ 133 O_IP_DST_LOOKUP, /* arg1=table number, u32=value */ 134 O_ANTISPOOF, /* none */ 135 O_JAIL, /* u32 = id */ 136 O_ALTQ, /* u32 = altq classif. qid */ 137 O_DIVERTED, /* arg1=bitmap (1:loop, 2:out) */ 138 O_TCPDATALEN, /* arg1 = tcp data len */ 139 O_IP6_SRC, /* address without mask */ 140 O_IP6_SRC_ME, /* my addresses */ 141 O_IP6_SRC_MASK, /* address with the mask */ 142 O_IP6_DST, 143 O_IP6_DST_ME, 144 O_IP6_DST_MASK, 145 O_FLOW6ID, /* for flow id tag in the ipv6 pkt */ 146 O_ICMP6TYPE, /* icmp6 packet type filtering */ 147 O_EXT_HDR, /* filtering for ipv6 extension header */ 148 O_IP6, 149 150 /* 151 * actions for ng_ipfw 152 */ 153 O_NETGRAPH, /* send to ng_ipfw */ 154 O_NGTEE, /* copy to ng_ipfw */ 155 156 O_IP4, 157 158 O_UNREACH6, /* arg1=icmpv6 code arg (deny) */ 159 160 O_LAST_OPCODE /* not an opcode! */ 161 }; 162 163 /* 164 * The extension header are filtered only for presence using a bit 165 * vector with a flag for each header. 166 */ 167 #define EXT_FRAGMENT 0x1 168 #define EXT_HOPOPTS 0x2 169 #define EXT_ROUTING 0x4 170 #define EXT_AH 0x8 171 #define EXT_ESP 0x10 172 #define EXT_DSTOPTS 0x20 173 174 /* 175 * Template for instructions. 176 * 177 * ipfw_insn is used for all instructions which require no operands, 178 * a single 16-bit value (arg1), or a couple of 8-bit values. 179 * 180 * For other instructions which require different/larger arguments 181 * we have derived structures, ipfw_insn_*. 182 * 183 * The size of the instruction (in 32-bit words) is in the low 184 * 6 bits of "len". The 2 remaining bits are used to implement 185 * NOT and OR on individual instructions. Given a type, you can 186 * compute the length to be put in "len" using F_INSN_SIZE(t) 187 * 188 * F_NOT negates the match result of the instruction. 189 * 190 * F_OR is used to build or blocks. By default, instructions 191 * are evaluated as part of a logical AND. An "or" block 192 * { X or Y or Z } contains F_OR set in all but the last 193 * instruction of the block. A match will cause the code 194 * to skip past the last instruction of the block. 195 * 196 * NOTA BENE: in a couple of places we assume that 197 * sizeof(ipfw_insn) == sizeof(u_int32_t) 198 * this needs to be fixed. 199 * 200 */ 201 typedef struct _ipfw_insn { /* template for instructions */ 202 enum ipfw_opcodes opcode:8; 203 u_int8_t len; /* numer of 32-byte words */ 204 #define F_NOT 0x80 205 #define F_OR 0x40 206 #define F_LEN_MASK 0x3f 207 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK) 208 209 u_int16_t arg1; 210 } ipfw_insn; 211 212 /* 213 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of 214 * a given type. 215 */ 216 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t)) 217 218 /* 219 * This is used to store an array of 16-bit entries (ports etc.) 220 */ 221 typedef struct _ipfw_insn_u16 { 222 ipfw_insn o; 223 u_int16_t ports[2]; /* there may be more */ 224 } ipfw_insn_u16; 225 226 /* 227 * This is used to store an array of 32-bit entries 228 * (uid, single IPv4 addresses etc.) 229 */ 230 typedef struct _ipfw_insn_u32 { 231 ipfw_insn o; 232 u_int32_t d[1]; /* one or more */ 233 } ipfw_insn_u32; 234 235 /* 236 * This is used to store IP addr-mask pairs. 237 */ 238 typedef struct _ipfw_insn_ip { 239 ipfw_insn o; 240 struct in_addr addr; 241 struct in_addr mask; 242 } ipfw_insn_ip; 243 244 /* 245 * This is used to forward to a given address (ip). 246 */ 247 typedef struct _ipfw_insn_sa { 248 ipfw_insn o; 249 struct sockaddr_in sa; 250 } ipfw_insn_sa; 251 252 /* 253 * This is used for MAC addr-mask pairs. 254 */ 255 typedef struct _ipfw_insn_mac { 256 ipfw_insn o; 257 u_char addr[12]; /* dst[6] + src[6] */ 258 u_char mask[12]; /* dst[6] + src[6] */ 259 } ipfw_insn_mac; 260 261 /* 262 * This is used for interface match rules (recv xx, xmit xx). 263 */ 264 typedef struct _ipfw_insn_if { 265 ipfw_insn o; 266 union { 267 struct in_addr ip; 268 int glob; 269 } p; 270 char name[IFNAMSIZ]; 271 } ipfw_insn_if; 272 273 /* 274 * This is used for pipe and queue actions, which need to store 275 * a single pointer (which can have different size on different 276 * architectures. 277 * Note that, because of previous instructions, pipe_ptr might 278 * be unaligned in the overall structure, so it needs to be 279 * manipulated with care. 280 */ 281 typedef struct _ipfw_insn_pipe { 282 ipfw_insn o; 283 void *pipe_ptr; /* XXX */ 284 } ipfw_insn_pipe; 285 286 /* 287 * This is used for storing an altq queue id number. 288 */ 289 typedef struct _ipfw_insn_altq { 290 ipfw_insn o; 291 u_int32_t qid; 292 } ipfw_insn_altq; 293 294 /* 295 * This is used for limit rules. 296 */ 297 typedef struct _ipfw_insn_limit { 298 ipfw_insn o; 299 u_int8_t _pad; 300 u_int8_t limit_mask; /* combination of DYN_* below */ 301 #define DYN_SRC_ADDR 0x1 302 #define DYN_SRC_PORT 0x2 303 #define DYN_DST_ADDR 0x4 304 #define DYN_DST_PORT 0x8 305 306 u_int16_t conn_limit; 307 } ipfw_insn_limit; 308 309 /* 310 * This is used for log instructions. 311 */ 312 typedef struct _ipfw_insn_log { 313 ipfw_insn o; 314 u_int32_t max_log; /* how many do we log -- 0 = all */ 315 u_int32_t log_left; /* how many left to log */ 316 } ipfw_insn_log; 317 318 /* Apply ipv6 mask on ipv6 addr */ 319 #define APPLY_MASK(addr,mask) \ 320 (addr)->__u6_addr.__u6_addr32[0] &= (mask)->__u6_addr.__u6_addr32[0]; \ 321 (addr)->__u6_addr.__u6_addr32[1] &= (mask)->__u6_addr.__u6_addr32[1]; \ 322 (addr)->__u6_addr.__u6_addr32[2] &= (mask)->__u6_addr.__u6_addr32[2]; \ 323 (addr)->__u6_addr.__u6_addr32[3] &= (mask)->__u6_addr.__u6_addr32[3]; 324 325 /* Structure for ipv6 */ 326 typedef struct _ipfw_insn_ip6 { 327 ipfw_insn o; 328 struct in6_addr addr6; 329 struct in6_addr mask6; 330 } ipfw_insn_ip6; 331 332 /* Used to support icmp6 types */ 333 typedef struct _ipfw_insn_icmp6 { 334 ipfw_insn o; 335 uint32_t d[7]; /* XXX This number si related to the netinet/icmp6.h 336 * define ICMP6_MAXTYPE 337 * as follows: n = ICMP6_MAXTYPE/32 + 1 338 * Actually is 203 339 */ 340 } ipfw_insn_icmp6; 341 342 /* 343 * Here we have the structure representing an ipfw rule. 344 * 345 * It starts with a general area (with link fields and counters) 346 * followed by an array of one or more instructions, which the code 347 * accesses as an array of 32-bit values. 348 * 349 * Given a rule pointer r: 350 * 351 * r->cmd is the start of the first instruction. 352 * ACTION_PTR(r) is the start of the first action (things to do 353 * once a rule matched). 354 * 355 * When assembling instruction, remember the following: 356 * 357 * + if a rule has a "keep-state" (or "limit") option, then the 358 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE 359 * + if a rule has a "log" option, then the first action 360 * (at ACTION_PTR(r)) MUST be O_LOG 361 * + if a rule has an "altq" option, it comes after "log" 362 * 363 * NOTE: we use a simple linked list of rules because we never need 364 * to delete a rule without scanning the list. We do not use 365 * queue(3) macros for portability and readability. 366 */ 367 368 struct ip_fw { 369 struct ip_fw *next; /* linked list of rules */ 370 struct ip_fw *next_rule; /* ptr to next [skipto] rule */ 371 /* 'next_rule' is used to pass up 'set_disable' status */ 372 373 u_int16_t act_ofs; /* offset of action in 32-bit units */ 374 u_int16_t cmd_len; /* # of 32-bit words in cmd */ 375 u_int16_t rulenum; /* rule number */ 376 u_int8_t set; /* rule set (0..31) */ 377 #define RESVD_SET 31 /* set for default and persistent rules */ 378 u_int8_t _pad; /* padding */ 379 380 /* These fields are present in all rules. */ 381 u_int64_t pcnt; /* Packet counter */ 382 u_int64_t bcnt; /* Byte counter */ 383 u_int32_t timestamp; /* tv_sec of last match */ 384 385 ipfw_insn cmd[1]; /* storage for commands */ 386 }; 387 388 #define ACTION_PTR(rule) \ 389 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) ) 390 391 #define RULESIZE(rule) (sizeof(struct ip_fw) + \ 392 ((struct ip_fw *)(rule))->cmd_len * 4 - 4) 393 394 /* 395 * This structure is used as a flow mask and a flow id for various 396 * parts of the code. 397 */ 398 struct ipfw_flow_id { 399 u_int32_t dst_ip; 400 u_int32_t src_ip; 401 u_int16_t dst_port; 402 u_int16_t src_port; 403 u_int8_t proto; 404 u_int8_t flags; /* protocol-specific flags */ 405 uint8_t addr_type; /* 4 = ipv4, 6 = ipv6, 1=ether ? */ 406 struct in6_addr dst_ip6; /* could also store MAC addr! */ 407 struct in6_addr src_ip6; 408 u_int32_t flow_id6; 409 u_int32_t frag_id6; 410 }; 411 412 #define IS_IP6_FLOW_ID(id) ((id)->addr_type == 6) 413 414 /* 415 * Dynamic ipfw rule. 416 */ 417 typedef struct _ipfw_dyn_rule ipfw_dyn_rule; 418 419 struct _ipfw_dyn_rule { 420 ipfw_dyn_rule *next; /* linked list of rules. */ 421 struct ip_fw *rule; /* pointer to rule */ 422 /* 'rule' is used to pass up the rule number (from the parent) */ 423 424 ipfw_dyn_rule *parent; /* pointer to parent rule */ 425 u_int64_t pcnt; /* packet match counter */ 426 u_int64_t bcnt; /* byte match counter */ 427 struct ipfw_flow_id id; /* (masked) flow id */ 428 u_int32_t expire; /* expire time */ 429 u_int32_t bucket; /* which bucket in hash table */ 430 u_int32_t state; /* state of this rule (typically a 431 * combination of TCP flags) 432 */ 433 u_int32_t ack_fwd; /* most recent ACKs in forward */ 434 u_int32_t ack_rev; /* and reverse directions (used */ 435 /* to generate keepalives) */ 436 u_int16_t dyn_type; /* rule type */ 437 u_int16_t count; /* refcount */ 438 }; 439 440 /* 441 * Definitions for IP option names. 442 */ 443 #define IP_FW_IPOPT_LSRR 0x01 444 #define IP_FW_IPOPT_SSRR 0x02 445 #define IP_FW_IPOPT_RR 0x04 446 #define IP_FW_IPOPT_TS 0x08 447 448 /* 449 * Definitions for TCP option names. 450 */ 451 #define IP_FW_TCPOPT_MSS 0x01 452 #define IP_FW_TCPOPT_WINDOW 0x02 453 #define IP_FW_TCPOPT_SACK 0x04 454 #define IP_FW_TCPOPT_TS 0x08 455 #define IP_FW_TCPOPT_CC 0x10 456 457 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */ 458 #define ICMP6_UNREACH_RST 0x100 /* fake ICMPv6 code (send a TCP RST) */ 459 460 /* 461 * These are used for lookup tables. 462 */ 463 typedef struct _ipfw_table_entry { 464 in_addr_t addr; /* network address */ 465 u_int32_t value; /* value */ 466 u_int16_t tbl; /* table number */ 467 u_int8_t masklen; /* mask length */ 468 } ipfw_table_entry; 469 470 typedef struct _ipfw_table { 471 u_int32_t size; /* size of entries in bytes */ 472 u_int32_t cnt; /* # of entries */ 473 u_int16_t tbl; /* table number */ 474 ipfw_table_entry ent[0]; /* entries */ 475 } ipfw_table; 476 477 /* 478 * Main firewall chains definitions and global var's definitions. 479 */ 480 #ifdef _KERNEL 481 482 /* Return values from ipfw_chk() */ 483 enum { 484 IP_FW_PASS = 0, 485 IP_FW_DENY, 486 IP_FW_DIVERT, 487 IP_FW_TEE, 488 IP_FW_DUMMYNET, 489 IP_FW_NETGRAPH, 490 IP_FW_NGTEE, 491 }; 492 493 /* flags for divert mtag */ 494 #define IP_FW_DIVERT_LOOPBACK_FLAG 0x00080000 495 #define IP_FW_DIVERT_OUTPUT_FLAG 0x00100000 496 497 /* 498 * Structure for collecting parameters to dummynet for ip6_output forwarding 499 */ 500 struct _ip6dn_args { 501 struct ip6_pktopts *opt_or; 502 struct route_in6 ro_or; 503 int flags_or; 504 struct ip6_moptions *im6o_or; 505 struct ifnet *origifp_or; 506 struct ifnet *ifp_or; 507 struct sockaddr_in6 dst_or; 508 u_long mtu_or; 509 struct route_in6 ro_pmtu_or; 510 }; 511 512 /* 513 * Arguments for calling ipfw_chk() and dummynet_io(). We put them 514 * all into a structure because this way it is easier and more 515 * efficient to pass variables around and extend the interface. 516 */ 517 struct ip_fw_args { 518 struct mbuf *m; /* the mbuf chain */ 519 struct ifnet *oif; /* output interface */ 520 struct sockaddr_in *next_hop; /* forward address */ 521 struct ip_fw *rule; /* matching rule */ 522 struct ether_header *eh; /* for bridged packets */ 523 524 int flags; /* for dummynet */ 525 526 struct ipfw_flow_id f_id; /* grabbed from IP header */ 527 u_int32_t cookie; /* a cookie depending on rule action */ 528 struct inpcb *inp; 529 530 struct _ip6dn_args dummypar; /* dummynet->ip6_output */ 531 }; 532 533 /* 534 * Function definitions. 535 */ 536 537 /* Firewall hooks */ 538 struct sockopt; 539 struct dn_flow_set; 540 541 int ipfw_check_in(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 542 int ipfw_check_out(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 543 544 int ipfw_chk(struct ip_fw_args *); 545 546 int ipfw_init(void); 547 void ipfw_destroy(void); 548 549 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */ 550 551 typedef int ip_fw_ctl_t(struct sockopt *); 552 extern ip_fw_ctl_t *ip_fw_ctl_ptr; 553 extern int fw_one_pass; 554 extern int fw_enable; 555 556 /* For kernel ipfw_ether and ipfw_bridge. */ 557 typedef int ip_fw_chk_t(struct ip_fw_args *args); 558 extern ip_fw_chk_t *ip_fw_chk_ptr; 559 #define IPFW_LOADED (ip_fw_chk_ptr != NULL) 560 561 #endif /* _KERNEL */ 562 #endif /* _IPFW2_H */ 563