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 */ 140 141 O_LAST_OPCODE /* not an opcode! */ 142 }; 143 144 /* 145 * Template for instructions. 146 * 147 * ipfw_insn is used for all instructions which require no operands, 148 * a single 16-bit value (arg1), or a couple of 8-bit values. 149 * 150 * For other instructions which require different/larger arguments 151 * we have derived structures, ipfw_insn_*. 152 * 153 * The size of the instruction (in 32-bit words) is in the low 154 * 6 bits of "len". The 2 remaining bits are used to implement 155 * NOT and OR on individual instructions. Given a type, you can 156 * compute the length to be put in "len" using F_INSN_SIZE(t) 157 * 158 * F_NOT negates the match result of the instruction. 159 * 160 * F_OR is used to build or blocks. By default, instructions 161 * are evaluated as part of a logical AND. An "or" block 162 * { X or Y or Z } contains F_OR set in all but the last 163 * instruction of the block. A match will cause the code 164 * to skip past the last instruction of the block. 165 * 166 * NOTA BENE: in a couple of places we assume that 167 * sizeof(ipfw_insn) == sizeof(u_int32_t) 168 * this needs to be fixed. 169 * 170 */ 171 typedef struct _ipfw_insn { /* template for instructions */ 172 enum ipfw_opcodes opcode:8; 173 u_int8_t len; /* numer of 32-byte words */ 174 #define F_NOT 0x80 175 #define F_OR 0x40 176 #define F_LEN_MASK 0x3f 177 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK) 178 179 u_int16_t arg1; 180 } ipfw_insn; 181 182 /* 183 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of 184 * a given type. 185 */ 186 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t)) 187 188 /* 189 * This is used to store an array of 16-bit entries (ports etc.) 190 */ 191 typedef struct _ipfw_insn_u16 { 192 ipfw_insn o; 193 u_int16_t ports[2]; /* there may be more */ 194 } ipfw_insn_u16; 195 196 /* 197 * This is used to store an array of 32-bit entries 198 * (uid, single IPv4 addresses etc.) 199 */ 200 typedef struct _ipfw_insn_u32 { 201 ipfw_insn o; 202 u_int32_t d[1]; /* one or more */ 203 } ipfw_insn_u32; 204 205 /* 206 * This is used to store IP addr-mask pairs. 207 */ 208 typedef struct _ipfw_insn_ip { 209 ipfw_insn o; 210 struct in_addr addr; 211 struct in_addr mask; 212 } ipfw_insn_ip; 213 214 /* 215 * This is used to forward to a given address (ip). 216 */ 217 typedef struct _ipfw_insn_sa { 218 ipfw_insn o; 219 struct sockaddr_in sa; 220 } ipfw_insn_sa; 221 222 /* 223 * This is used for MAC addr-mask pairs. 224 */ 225 typedef struct _ipfw_insn_mac { 226 ipfw_insn o; 227 u_char addr[12]; /* dst[6] + src[6] */ 228 u_char mask[12]; /* dst[6] + src[6] */ 229 } ipfw_insn_mac; 230 231 /* 232 * This is used for interface match rules (recv xx, xmit xx). 233 */ 234 typedef struct _ipfw_insn_if { 235 ipfw_insn o; 236 union { 237 struct in_addr ip; 238 int glob; 239 } p; 240 char name[IFNAMSIZ]; 241 } ipfw_insn_if; 242 243 /* 244 * This is used for pipe and queue actions, which need to store 245 * a single pointer (which can have different size on different 246 * architectures. 247 * Note that, because of previous instructions, pipe_ptr might 248 * be unaligned in the overall structure, so it needs to be 249 * manipulated with care. 250 */ 251 typedef struct _ipfw_insn_pipe { 252 ipfw_insn o; 253 void *pipe_ptr; /* XXX */ 254 } ipfw_insn_pipe; 255 256 /* 257 * This is used for storing an altq queue id number. 258 */ 259 typedef struct _ipfw_insn_altq { 260 ipfw_insn o; 261 u_int32_t qid; 262 } ipfw_insn_altq; 263 264 /* 265 * This is used for limit rules. 266 */ 267 typedef struct _ipfw_insn_limit { 268 ipfw_insn o; 269 u_int8_t _pad; 270 u_int8_t limit_mask; /* combination of DYN_* below */ 271 #define DYN_SRC_ADDR 0x1 272 #define DYN_SRC_PORT 0x2 273 #define DYN_DST_ADDR 0x4 274 #define DYN_DST_PORT 0x8 275 276 u_int16_t conn_limit; 277 } ipfw_insn_limit; 278 279 /* 280 * This is used for log instructions. 281 */ 282 typedef struct _ipfw_insn_log { 283 ipfw_insn o; 284 u_int32_t max_log; /* how many do we log -- 0 = all */ 285 u_int32_t log_left; /* how many left to log */ 286 } ipfw_insn_log; 287 288 /* 289 * Here we have the structure representing an ipfw rule. 290 * 291 * It starts with a general area (with link fields and counters) 292 * followed by an array of one or more instructions, which the code 293 * accesses as an array of 32-bit values. 294 * 295 * Given a rule pointer r: 296 * 297 * r->cmd is the start of the first instruction. 298 * ACTION_PTR(r) is the start of the first action (things to do 299 * once a rule matched). 300 * 301 * When assembling instruction, remember the following: 302 * 303 * + if a rule has a "keep-state" (or "limit") option, then the 304 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE 305 * + if a rule has a "log" option, then the first action 306 * (at ACTION_PTR(r)) MUST be O_LOG 307 * + if a rule has an "altq" option, it comes after "log" 308 * 309 * NOTE: we use a simple linked list of rules because we never need 310 * to delete a rule without scanning the list. We do not use 311 * queue(3) macros for portability and readability. 312 */ 313 314 struct ip_fw { 315 struct ip_fw *next; /* linked list of rules */ 316 struct ip_fw *next_rule; /* ptr to next [skipto] rule */ 317 /* 'next_rule' is used to pass up 'set_disable' status */ 318 319 u_int16_t act_ofs; /* offset of action in 32-bit units */ 320 u_int16_t cmd_len; /* # of 32-bit words in cmd */ 321 u_int16_t rulenum; /* rule number */ 322 u_int8_t set; /* rule set (0..31) */ 323 #define RESVD_SET 31 /* set for default and persistent rules */ 324 u_int8_t _pad; /* padding */ 325 326 /* These fields are present in all rules. */ 327 u_int64_t pcnt; /* Packet counter */ 328 u_int64_t bcnt; /* Byte counter */ 329 u_int32_t timestamp; /* tv_sec of last match */ 330 331 ipfw_insn cmd[1]; /* storage for commands */ 332 }; 333 334 #define ACTION_PTR(rule) \ 335 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) ) 336 337 #define RULESIZE(rule) (sizeof(struct ip_fw) + \ 338 ((struct ip_fw *)(rule))->cmd_len * 4 - 4) 339 340 /* 341 * This structure is used as a flow mask and a flow id for various 342 * parts of the code. 343 */ 344 struct ipfw_flow_id { 345 u_int32_t dst_ip; 346 u_int32_t src_ip; 347 u_int16_t dst_port; 348 u_int16_t src_port; 349 u_int8_t proto; 350 u_int8_t flags; /* protocol-specific flags */ 351 }; 352 353 /* 354 * Dynamic ipfw rule. 355 */ 356 typedef struct _ipfw_dyn_rule ipfw_dyn_rule; 357 358 struct _ipfw_dyn_rule { 359 ipfw_dyn_rule *next; /* linked list of rules. */ 360 struct ip_fw *rule; /* pointer to rule */ 361 /* 'rule' is used to pass up the rule number (from the parent) */ 362 363 ipfw_dyn_rule *parent; /* pointer to parent rule */ 364 u_int64_t pcnt; /* packet match counter */ 365 u_int64_t bcnt; /* byte match counter */ 366 struct ipfw_flow_id id; /* (masked) flow id */ 367 u_int32_t expire; /* expire time */ 368 u_int32_t bucket; /* which bucket in hash table */ 369 u_int32_t state; /* state of this rule (typically a 370 * combination of TCP flags) 371 */ 372 u_int32_t ack_fwd; /* most recent ACKs in forward */ 373 u_int32_t ack_rev; /* and reverse directions (used */ 374 /* to generate keepalives) */ 375 u_int16_t dyn_type; /* rule type */ 376 u_int16_t count; /* refcount */ 377 }; 378 379 /* 380 * Definitions for IP option names. 381 */ 382 #define IP_FW_IPOPT_LSRR 0x01 383 #define IP_FW_IPOPT_SSRR 0x02 384 #define IP_FW_IPOPT_RR 0x04 385 #define IP_FW_IPOPT_TS 0x08 386 387 /* 388 * Definitions for TCP option names. 389 */ 390 #define IP_FW_TCPOPT_MSS 0x01 391 #define IP_FW_TCPOPT_WINDOW 0x02 392 #define IP_FW_TCPOPT_SACK 0x04 393 #define IP_FW_TCPOPT_TS 0x08 394 #define IP_FW_TCPOPT_CC 0x10 395 396 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */ 397 398 /* 399 * These are used for lookup tables. 400 */ 401 typedef struct _ipfw_table_entry { 402 in_addr_t addr; /* network address */ 403 u_int32_t value; /* value */ 404 u_int16_t tbl; /* table number */ 405 u_int8_t masklen; /* mask length */ 406 } ipfw_table_entry; 407 408 typedef struct _ipfw_table { 409 u_int32_t size; /* size of entries in bytes */ 410 u_int32_t cnt; /* # of entries */ 411 u_int16_t tbl; /* table number */ 412 ipfw_table_entry ent[0]; /* entries */ 413 } ipfw_table; 414 415 /* 416 * Main firewall chains definitions and global var's definitions. 417 */ 418 #ifdef _KERNEL 419 420 /* Return values from ipfw_chk() */ 421 enum { 422 IP_FW_PASS = 0, 423 IP_FW_DENY, 424 IP_FW_DIVERT, 425 IP_FW_TEE, 426 IP_FW_DUMMYNET, 427 IP_FW_NETGRAPH, 428 }; 429 430 /* flags for divert mtag */ 431 #define IP_FW_DIVERT_LOOPBACK_FLAG 0x00080000 432 #define IP_FW_DIVERT_OUTPUT_FLAG 0x00100000 433 434 /* 435 * Arguments for calling ipfw_chk() and dummynet_io(). We put them 436 * all into a structure because this way it is easier and more 437 * efficient to pass variables around and extend the interface. 438 */ 439 struct ip_fw_args { 440 struct mbuf *m; /* the mbuf chain */ 441 struct ifnet *oif; /* output interface */ 442 struct sockaddr_in *next_hop; /* forward address */ 443 struct ip_fw *rule; /* matching rule */ 444 struct ether_header *eh; /* for bridged packets */ 445 446 int flags; /* for dummynet */ 447 448 struct ipfw_flow_id f_id; /* grabbed from IP header */ 449 u_int32_t cookie; /* a cookie depending on rule action */ 450 struct inpcb *inp; 451 }; 452 453 /* 454 * Function definitions. 455 */ 456 457 /* Firewall hooks */ 458 struct sockopt; 459 struct dn_flow_set; 460 461 int ipfw_check_in(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 462 int ipfw_check_out(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 463 464 int ipfw_chk(struct ip_fw_args *); 465 466 int ipfw_init(void); 467 void ipfw_destroy(void); 468 469 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */ 470 471 typedef int ip_fw_ctl_t(struct sockopt *); 472 extern ip_fw_ctl_t *ip_fw_ctl_ptr; 473 extern int fw_one_pass; 474 extern int fw_enable; 475 476 /* For kernel ipfw_ether and ipfw_bridge. */ 477 typedef int ip_fw_chk_t(struct ip_fw_args *args); 478 extern ip_fw_chk_t *ip_fw_chk_ptr; 479 #define IPFW_LOADED (ip_fw_chk_ptr != NULL) 480 481 #endif /* _KERNEL */ 482 #endif /* _IPFW2_H */ 483