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 * 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 O_ANTISPOOF, /* 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_JAIL, /* u32 = id */ 136 137 O_LAST_OPCODE /* not an opcode! */ 138 }; 139 140 /* 141 * Template for instructions. 142 * 143 * ipfw_insn is used for all instructions which require no operands, 144 * a single 16-bit value (arg1), or a couple of 8-bit values. 145 * 146 * For other instructions which require different/larger arguments 147 * we have derived structures, ipfw_insn_*. 148 * 149 * The size of the instruction (in 32-bit words) is in the low 150 * 6 bits of "len". The 2 remaining bits are used to implement 151 * NOT and OR on individual instructions. Given a type, you can 152 * compute the length to be put in "len" using F_INSN_SIZE(t) 153 * 154 * F_NOT negates the match result of the instruction. 155 * 156 * F_OR is used to build or blocks. By default, instructions 157 * are evaluated as part of a logical AND. An "or" block 158 * { X or Y or Z } contains F_OR set in all but the last 159 * instruction of the block. A match will cause the code 160 * to skip past the last instruction of the block. 161 * 162 * NOTA BENE: in a couple of places we assume that 163 * sizeof(ipfw_insn) == sizeof(u_int32_t) 164 * this needs to be fixed. 165 * 166 */ 167 typedef struct _ipfw_insn { /* template for instructions */ 168 enum ipfw_opcodes opcode:8; 169 u_int8_t len; /* numer of 32-byte words */ 170 #define F_NOT 0x80 171 #define F_OR 0x40 172 #define F_LEN_MASK 0x3f 173 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK) 174 175 u_int16_t arg1; 176 } ipfw_insn; 177 178 /* 179 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of 180 * a given type. 181 */ 182 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t)) 183 184 /* 185 * This is used to store an array of 16-bit entries (ports etc.) 186 */ 187 typedef struct _ipfw_insn_u16 { 188 ipfw_insn o; 189 u_int16_t ports[2]; /* there may be more */ 190 } ipfw_insn_u16; 191 192 /* 193 * This is used to store an array of 32-bit entries 194 * (uid, single IPv4 addresses etc.) 195 */ 196 typedef struct _ipfw_insn_u32 { 197 ipfw_insn o; 198 u_int32_t d[1]; /* one or more */ 199 } ipfw_insn_u32; 200 201 /* 202 * This is used to store IP addr-mask pairs. 203 */ 204 typedef struct _ipfw_insn_ip { 205 ipfw_insn o; 206 struct in_addr addr; 207 struct in_addr mask; 208 } ipfw_insn_ip; 209 210 /* 211 * This is used to forward to a given address (ip). 212 */ 213 typedef struct _ipfw_insn_sa { 214 ipfw_insn o; 215 struct sockaddr_in sa; 216 } ipfw_insn_sa; 217 218 /* 219 * This is used for MAC addr-mask pairs. 220 */ 221 typedef struct _ipfw_insn_mac { 222 ipfw_insn o; 223 u_char addr[12]; /* dst[6] + src[6] */ 224 u_char mask[12]; /* dst[6] + src[6] */ 225 } ipfw_insn_mac; 226 227 /* 228 * This is used for interface match rules (recv xx, xmit xx). 229 */ 230 typedef struct _ipfw_insn_if { 231 ipfw_insn o; 232 union { 233 struct in_addr ip; 234 int glob; 235 } p; 236 char name[IFNAMSIZ]; 237 } ipfw_insn_if; 238 239 /* 240 * This is used for pipe and queue actions, which need to store 241 * a single pointer (which can have different size on different 242 * architectures. 243 * Note that, because of previous instructions, pipe_ptr might 244 * be unaligned in the overall structure, so it needs to be 245 * manipulated with care. 246 */ 247 typedef struct _ipfw_insn_pipe { 248 ipfw_insn o; 249 void *pipe_ptr; /* XXX */ 250 } ipfw_insn_pipe; 251 252 /* 253 * This is used for limit rules. 254 */ 255 typedef struct _ipfw_insn_limit { 256 ipfw_insn o; 257 u_int8_t _pad; 258 u_int8_t limit_mask; /* combination of DYN_* below */ 259 #define DYN_SRC_ADDR 0x1 260 #define DYN_SRC_PORT 0x2 261 #define DYN_DST_ADDR 0x4 262 #define DYN_DST_PORT 0x8 263 264 u_int16_t conn_limit; 265 } ipfw_insn_limit; 266 267 /* 268 * This is used for log instructions. 269 */ 270 typedef struct _ipfw_insn_log { 271 ipfw_insn o; 272 u_int32_t max_log; /* how many do we log -- 0 = all */ 273 u_int32_t log_left; /* how many left to log */ 274 } ipfw_insn_log; 275 276 /* 277 * Here we have the structure representing an ipfw rule. 278 * 279 * It starts with a general area (with link fields and counters) 280 * followed by an array of one or more instructions, which the code 281 * accesses as an array of 32-bit values. 282 * 283 * Given a rule pointer r: 284 * 285 * r->cmd is the start of the first instruction. 286 * ACTION_PTR(r) is the start of the first action (things to do 287 * once a rule matched). 288 * 289 * When assembling instruction, remember the following: 290 * 291 * + if a rule has a "keep-state" (or "limit") option, then the 292 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE 293 * + if a rule has a "log" option, then the first action 294 * (at ACTION_PTR(r)) MUST be O_LOG 295 * 296 * NOTE: we use a simple linked list of rules because we never need 297 * to delete a rule without scanning the list. We do not use 298 * queue(3) macros for portability and readability. 299 */ 300 301 struct ip_fw { 302 struct ip_fw *next; /* linked list of rules */ 303 struct ip_fw *next_rule; /* ptr to next [skipto] rule */ 304 /* 'next_rule' is used to pass up 'set_disable' status */ 305 306 u_int16_t act_ofs; /* offset of action in 32-bit units */ 307 u_int16_t cmd_len; /* # of 32-bit words in cmd */ 308 u_int16_t rulenum; /* rule number */ 309 u_int8_t set; /* rule set (0..31) */ 310 #define RESVD_SET 31 /* set for default and persistent rules */ 311 u_int8_t _pad; /* padding */ 312 313 /* These fields are present in all rules. */ 314 u_int64_t pcnt; /* Packet counter */ 315 u_int64_t bcnt; /* Byte counter */ 316 u_int32_t timestamp; /* tv_sec of last match */ 317 318 ipfw_insn cmd[1]; /* storage for commands */ 319 }; 320 321 #define ACTION_PTR(rule) \ 322 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) ) 323 324 #define RULESIZE(rule) (sizeof(struct ip_fw) + \ 325 ((struct ip_fw *)(rule))->cmd_len * 4 - 4) 326 327 /* 328 * This structure is used as a flow mask and a flow id for various 329 * parts of the code. 330 */ 331 struct ipfw_flow_id { 332 u_int32_t dst_ip; 333 u_int32_t src_ip; 334 u_int16_t dst_port; 335 u_int16_t src_port; 336 u_int8_t proto; 337 u_int8_t flags; /* protocol-specific flags */ 338 }; 339 340 /* 341 * Dynamic ipfw rule. 342 */ 343 typedef struct _ipfw_dyn_rule ipfw_dyn_rule; 344 345 struct _ipfw_dyn_rule { 346 ipfw_dyn_rule *next; /* linked list of rules. */ 347 struct ip_fw *rule; /* pointer to rule */ 348 /* 'rule' is used to pass up the rule number (from the parent) */ 349 350 ipfw_dyn_rule *parent; /* pointer to parent rule */ 351 u_int64_t pcnt; /* packet match counter */ 352 u_int64_t bcnt; /* byte match counter */ 353 struct ipfw_flow_id id; /* (masked) flow id */ 354 u_int32_t expire; /* expire time */ 355 u_int32_t bucket; /* which bucket in hash table */ 356 u_int32_t state; /* state of this rule (typically a 357 * combination of TCP flags) 358 */ 359 u_int32_t ack_fwd; /* most recent ACKs in forward */ 360 u_int32_t ack_rev; /* and reverse directions (used */ 361 /* to generate keepalives) */ 362 u_int16_t dyn_type; /* rule type */ 363 u_int16_t count; /* refcount */ 364 }; 365 366 /* 367 * Definitions for IP option names. 368 */ 369 #define IP_FW_IPOPT_LSRR 0x01 370 #define IP_FW_IPOPT_SSRR 0x02 371 #define IP_FW_IPOPT_RR 0x04 372 #define IP_FW_IPOPT_TS 0x08 373 374 /* 375 * Definitions for TCP option names. 376 */ 377 #define IP_FW_TCPOPT_MSS 0x01 378 #define IP_FW_TCPOPT_WINDOW 0x02 379 #define IP_FW_TCPOPT_SACK 0x04 380 #define IP_FW_TCPOPT_TS 0x08 381 #define IP_FW_TCPOPT_CC 0x10 382 383 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */ 384 385 /* 386 * These are used for lookup tables. 387 */ 388 typedef struct _ipfw_table_entry { 389 in_addr_t addr; /* network address */ 390 u_int32_t value; /* value */ 391 u_int16_t tbl; /* table number */ 392 u_int8_t masklen; /* mask length */ 393 } ipfw_table_entry; 394 395 typedef struct _ipfw_table { 396 u_int32_t size; /* size of entries in bytes */ 397 u_int32_t cnt; /* # of entries */ 398 u_int16_t tbl; /* table number */ 399 ipfw_table_entry ent[0]; /* entries */ 400 } ipfw_table; 401 402 /* 403 * Main firewall chains definitions and global var's definitions. 404 */ 405 #ifdef _KERNEL 406 407 #define IP_FW_PORT_DYNT_FLAG 0x10000 408 #define IP_FW_PORT_TEE_FLAG 0x20000 409 #define IP_FW_PORT_DENY_FLAG 0x40000 410 411 /* 412 * Arguments for calling ipfw_chk() and dummynet_io(). We put them 413 * all into a structure because this way it is easier and more 414 * efficient to pass variables around and extend the interface. 415 */ 416 struct ip_fw_args { 417 struct mbuf *m; /* the mbuf chain */ 418 struct ifnet *oif; /* output interface */ 419 struct sockaddr_in *next_hop; /* forward address */ 420 struct ip_fw *rule; /* matching rule */ 421 struct ether_header *eh; /* for bridged packets */ 422 423 struct route *ro; /* for dummynet */ 424 struct sockaddr_in *dst; /* for dummynet */ 425 int flags; /* for dummynet */ 426 427 struct ipfw_flow_id f_id; /* grabbed from IP header */ 428 u_int32_t retval; 429 }; 430 431 /* 432 * Function definitions. 433 */ 434 435 /* Firewall hooks */ 436 struct sockopt; 437 struct dn_flow_set; 438 439 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */ 440 441 typedef int ip_fw_chk_t (struct ip_fw_args *args); 442 typedef int ip_fw_ctl_t (struct sockopt *); 443 extern ip_fw_chk_t *ip_fw_chk_ptr; 444 extern ip_fw_ctl_t *ip_fw_ctl_ptr; 445 extern int fw_one_pass; 446 extern int fw_enable; 447 #define IPFW_LOADED (ip_fw_chk_ptr != NULL) 448 #endif /* _KERNEL */ 449 450 #endif /* _IPFW2_H */ 451