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_LAST_OPCODE /* not an opcode! */ 159 }; 160 161 /* 162 * The extension header are filtered only for presence using a bit 163 * vector with a flag for each header. 164 */ 165 #define EXT_FRAGMENT 0x1 166 #define EXT_HOPOPTS 0x2 167 #define EXT_ROUTING 0x4 168 #define EXT_AH 0x8 169 #define EXT_ESP 0x10 170 171 /* 172 * Template for instructions. 173 * 174 * ipfw_insn is used for all instructions which require no operands, 175 * a single 16-bit value (arg1), or a couple of 8-bit values. 176 * 177 * For other instructions which require different/larger arguments 178 * we have derived structures, ipfw_insn_*. 179 * 180 * The size of the instruction (in 32-bit words) is in the low 181 * 6 bits of "len". The 2 remaining bits are used to implement 182 * NOT and OR on individual instructions. Given a type, you can 183 * compute the length to be put in "len" using F_INSN_SIZE(t) 184 * 185 * F_NOT negates the match result of the instruction. 186 * 187 * F_OR is used to build or blocks. By default, instructions 188 * are evaluated as part of a logical AND. An "or" block 189 * { X or Y or Z } contains F_OR set in all but the last 190 * instruction of the block. A match will cause the code 191 * to skip past the last instruction of the block. 192 * 193 * NOTA BENE: in a couple of places we assume that 194 * sizeof(ipfw_insn) == sizeof(u_int32_t) 195 * this needs to be fixed. 196 * 197 */ 198 typedef struct _ipfw_insn { /* template for instructions */ 199 enum ipfw_opcodes opcode:8; 200 u_int8_t len; /* numer of 32-byte words */ 201 #define F_NOT 0x80 202 #define F_OR 0x40 203 #define F_LEN_MASK 0x3f 204 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK) 205 206 u_int16_t arg1; 207 } ipfw_insn; 208 209 /* 210 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of 211 * a given type. 212 */ 213 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t)) 214 215 /* 216 * This is used to store an array of 16-bit entries (ports etc.) 217 */ 218 typedef struct _ipfw_insn_u16 { 219 ipfw_insn o; 220 u_int16_t ports[2]; /* there may be more */ 221 } ipfw_insn_u16; 222 223 /* 224 * This is used to store an array of 32-bit entries 225 * (uid, single IPv4 addresses etc.) 226 */ 227 typedef struct _ipfw_insn_u32 { 228 ipfw_insn o; 229 u_int32_t d[1]; /* one or more */ 230 } ipfw_insn_u32; 231 232 /* 233 * This is used to store IP addr-mask pairs. 234 */ 235 typedef struct _ipfw_insn_ip { 236 ipfw_insn o; 237 struct in_addr addr; 238 struct in_addr mask; 239 } ipfw_insn_ip; 240 241 /* 242 * This is used to forward to a given address (ip). 243 */ 244 typedef struct _ipfw_insn_sa { 245 ipfw_insn o; 246 struct sockaddr_in sa; 247 } ipfw_insn_sa; 248 249 /* 250 * This is used for MAC addr-mask pairs. 251 */ 252 typedef struct _ipfw_insn_mac { 253 ipfw_insn o; 254 u_char addr[12]; /* dst[6] + src[6] */ 255 u_char mask[12]; /* dst[6] + src[6] */ 256 } ipfw_insn_mac; 257 258 /* 259 * This is used for interface match rules (recv xx, xmit xx). 260 */ 261 typedef struct _ipfw_insn_if { 262 ipfw_insn o; 263 union { 264 struct in_addr ip; 265 int glob; 266 } p; 267 char name[IFNAMSIZ]; 268 } ipfw_insn_if; 269 270 /* 271 * This is used for pipe and queue actions, which need to store 272 * a single pointer (which can have different size on different 273 * architectures. 274 * Note that, because of previous instructions, pipe_ptr might 275 * be unaligned in the overall structure, so it needs to be 276 * manipulated with care. 277 */ 278 typedef struct _ipfw_insn_pipe { 279 ipfw_insn o; 280 void *pipe_ptr; /* XXX */ 281 } ipfw_insn_pipe; 282 283 /* 284 * This is used for storing an altq queue id number. 285 */ 286 typedef struct _ipfw_insn_altq { 287 ipfw_insn o; 288 u_int32_t qid; 289 } ipfw_insn_altq; 290 291 /* 292 * This is used for limit rules. 293 */ 294 typedef struct _ipfw_insn_limit { 295 ipfw_insn o; 296 u_int8_t _pad; 297 u_int8_t limit_mask; /* combination of DYN_* below */ 298 #define DYN_SRC_ADDR 0x1 299 #define DYN_SRC_PORT 0x2 300 #define DYN_DST_ADDR 0x4 301 #define DYN_DST_PORT 0x8 302 303 u_int16_t conn_limit; 304 } ipfw_insn_limit; 305 306 /* 307 * This is used for log instructions. 308 */ 309 typedef struct _ipfw_insn_log { 310 ipfw_insn o; 311 u_int32_t max_log; /* how many do we log -- 0 = all */ 312 u_int32_t log_left; /* how many left to log */ 313 } ipfw_insn_log; 314 315 /* Apply ipv6 mask on ipv6 addr */ 316 #define APPLY_MASK(addr,mask) \ 317 (addr)->__u6_addr.__u6_addr32[0] &= (mask)->__u6_addr.__u6_addr32[0]; \ 318 (addr)->__u6_addr.__u6_addr32[1] &= (mask)->__u6_addr.__u6_addr32[1]; \ 319 (addr)->__u6_addr.__u6_addr32[2] &= (mask)->__u6_addr.__u6_addr32[2]; \ 320 (addr)->__u6_addr.__u6_addr32[3] &= (mask)->__u6_addr.__u6_addr32[3]; 321 322 /* Structure for ipv6 */ 323 typedef struct _ipfw_insn_ip6 { 324 ipfw_insn o; 325 struct in6_addr addr6; 326 struct in6_addr mask6; 327 } ipfw_insn_ip6; 328 329 /* Used to support icmp6 types */ 330 typedef struct _ipfw_insn_icmp6 { 331 ipfw_insn o; 332 uint32_t d[7]; /* XXX This number si related to the netinet/icmp6.h 333 * define ICMP6_MAXTYPE 334 * as follows: n = ICMP6_MAXTYPE/32 + 1 335 * Actually is 203 336 */ 337 } ipfw_insn_icmp6; 338 339 /* 340 * Here we have the structure representing an ipfw rule. 341 * 342 * It starts with a general area (with link fields and counters) 343 * followed by an array of one or more instructions, which the code 344 * accesses as an array of 32-bit values. 345 * 346 * Given a rule pointer r: 347 * 348 * r->cmd is the start of the first instruction. 349 * ACTION_PTR(r) is the start of the first action (things to do 350 * once a rule matched). 351 * 352 * When assembling instruction, remember the following: 353 * 354 * + if a rule has a "keep-state" (or "limit") option, then the 355 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE 356 * + if a rule has a "log" option, then the first action 357 * (at ACTION_PTR(r)) MUST be O_LOG 358 * + if a rule has an "altq" option, it comes after "log" 359 * 360 * NOTE: we use a simple linked list of rules because we never need 361 * to delete a rule without scanning the list. We do not use 362 * queue(3) macros for portability and readability. 363 */ 364 365 struct ip_fw { 366 struct ip_fw *next; /* linked list of rules */ 367 struct ip_fw *next_rule; /* ptr to next [skipto] rule */ 368 /* 'next_rule' is used to pass up 'set_disable' status */ 369 370 u_int16_t act_ofs; /* offset of action in 32-bit units */ 371 u_int16_t cmd_len; /* # of 32-bit words in cmd */ 372 u_int16_t rulenum; /* rule number */ 373 u_int8_t set; /* rule set (0..31) */ 374 #define RESVD_SET 31 /* set for default and persistent rules */ 375 u_int8_t _pad; /* padding */ 376 377 /* These fields are present in all rules. */ 378 u_int64_t pcnt; /* Packet counter */ 379 u_int64_t bcnt; /* Byte counter */ 380 u_int32_t timestamp; /* tv_sec of last match */ 381 382 ipfw_insn cmd[1]; /* storage for commands */ 383 }; 384 385 #define ACTION_PTR(rule) \ 386 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) ) 387 388 #define RULESIZE(rule) (sizeof(struct ip_fw) + \ 389 ((struct ip_fw *)(rule))->cmd_len * 4 - 4) 390 391 /* 392 * This structure is used as a flow mask and a flow id for various 393 * parts of the code. 394 */ 395 struct ipfw_flow_id { 396 u_int32_t dst_ip; 397 u_int32_t src_ip; 398 u_int16_t dst_port; 399 u_int16_t src_port; 400 u_int8_t proto; 401 u_int8_t flags; /* protocol-specific flags */ 402 uint8_t addr_type; /* 4 = ipv4, 6 = ipv6, 1=ether ? */ 403 struct in6_addr dst_ip6; /* could also store MAC addr! */ 404 struct in6_addr src_ip6; 405 u_int32_t flow_id6; 406 }; 407 408 #define IS_IP6_FLOW_ID(id) ((id)->addr_type == 6) 409 410 /* 411 * Dynamic ipfw rule. 412 */ 413 typedef struct _ipfw_dyn_rule ipfw_dyn_rule; 414 415 struct _ipfw_dyn_rule { 416 ipfw_dyn_rule *next; /* linked list of rules. */ 417 struct ip_fw *rule; /* pointer to rule */ 418 /* 'rule' is used to pass up the rule number (from the parent) */ 419 420 ipfw_dyn_rule *parent; /* pointer to parent rule */ 421 u_int64_t pcnt; /* packet match counter */ 422 u_int64_t bcnt; /* byte match counter */ 423 struct ipfw_flow_id id; /* (masked) flow id */ 424 u_int32_t expire; /* expire time */ 425 u_int32_t bucket; /* which bucket in hash table */ 426 u_int32_t state; /* state of this rule (typically a 427 * combination of TCP flags) 428 */ 429 u_int32_t ack_fwd; /* most recent ACKs in forward */ 430 u_int32_t ack_rev; /* and reverse directions (used */ 431 /* to generate keepalives) */ 432 u_int16_t dyn_type; /* rule type */ 433 u_int16_t count; /* refcount */ 434 }; 435 436 /* 437 * Definitions for IP option names. 438 */ 439 #define IP_FW_IPOPT_LSRR 0x01 440 #define IP_FW_IPOPT_SSRR 0x02 441 #define IP_FW_IPOPT_RR 0x04 442 #define IP_FW_IPOPT_TS 0x08 443 444 /* 445 * Definitions for TCP option names. 446 */ 447 #define IP_FW_TCPOPT_MSS 0x01 448 #define IP_FW_TCPOPT_WINDOW 0x02 449 #define IP_FW_TCPOPT_SACK 0x04 450 #define IP_FW_TCPOPT_TS 0x08 451 #define IP_FW_TCPOPT_CC 0x10 452 453 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */ 454 455 /* 456 * These are used for lookup tables. 457 */ 458 typedef struct _ipfw_table_entry { 459 in_addr_t addr; /* network address */ 460 u_int32_t value; /* value */ 461 u_int16_t tbl; /* table number */ 462 u_int8_t masklen; /* mask length */ 463 } ipfw_table_entry; 464 465 typedef struct _ipfw_table { 466 u_int32_t size; /* size of entries in bytes */ 467 u_int32_t cnt; /* # of entries */ 468 u_int16_t tbl; /* table number */ 469 ipfw_table_entry ent[0]; /* entries */ 470 } ipfw_table; 471 472 /* 473 * Main firewall chains definitions and global var's definitions. 474 */ 475 #ifdef _KERNEL 476 477 /* Return values from ipfw_chk() */ 478 enum { 479 IP_FW_PASS = 0, 480 IP_FW_DENY, 481 IP_FW_DIVERT, 482 IP_FW_TEE, 483 IP_FW_DUMMYNET, 484 IP_FW_NETGRAPH, 485 IP_FW_NGTEE, 486 }; 487 488 /* flags for divert mtag */ 489 #define IP_FW_DIVERT_LOOPBACK_FLAG 0x00080000 490 #define IP_FW_DIVERT_OUTPUT_FLAG 0x00100000 491 492 /* 493 * Structure for collecting parameters to dummynet for ip6_output forwarding 494 */ 495 struct _ip6dn_args { 496 struct ip6_pktopts *opt_or; 497 struct route_in6 ro_or; 498 int flags_or; 499 struct ip6_moptions *im6o_or; 500 struct ifnet *origifp_or; 501 struct ifnet *ifp_or; 502 struct sockaddr_in6 dst_or; 503 u_long mtu_or; 504 struct route_in6 ro_pmtu_or; 505 }; 506 507 /* 508 * Arguments for calling ipfw_chk() and dummynet_io(). We put them 509 * all into a structure because this way it is easier and more 510 * efficient to pass variables around and extend the interface. 511 */ 512 struct ip_fw_args { 513 struct mbuf *m; /* the mbuf chain */ 514 struct ifnet *oif; /* output interface */ 515 struct sockaddr_in *next_hop; /* forward address */ 516 struct ip_fw *rule; /* matching rule */ 517 struct ether_header *eh; /* for bridged packets */ 518 519 int flags; /* for dummynet */ 520 521 struct ipfw_flow_id f_id; /* grabbed from IP header */ 522 u_int32_t cookie; /* a cookie depending on rule action */ 523 struct inpcb *inp; 524 525 struct _ip6dn_args dummypar; /* dummynet->ip6_output */ 526 }; 527 528 /* 529 * Function definitions. 530 */ 531 532 /* Firewall hooks */ 533 struct sockopt; 534 struct dn_flow_set; 535 536 int ipfw_check_in(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 537 int ipfw_check_out(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 538 539 int ipfw_chk(struct ip_fw_args *); 540 541 int ipfw_init(void); 542 void ipfw_destroy(void); 543 544 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */ 545 546 typedef int ip_fw_ctl_t(struct sockopt *); 547 extern ip_fw_ctl_t *ip_fw_ctl_ptr; 548 extern int fw_one_pass; 549 extern int fw_enable; 550 551 /* For kernel ipfw_ether and ipfw_bridge. */ 552 typedef int ip_fw_chk_t(struct ip_fw_args *args); 553 extern ip_fw_chk_t *ip_fw_chk_ptr; 554 #define IPFW_LOADED (ip_fw_chk_ptr != NULL) 555 556 #endif /* _KERNEL */ 557 #endif /* _IPFW2_H */ 558