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. 48 */ 49 50 enum ipfw_opcodes { /* arguments (4 byte each) */ 51 O_NOP, 52 53 O_IP_SRC, /* u32 = IP */ 54 O_IP_SRC_MASK, /* ip = IP/mask */ 55 O_IP_SRC_ME, /* none */ 56 O_IP_SRC_SET, /* u32=base, arg1=len, bitmap */ 57 58 O_IP_DST, /* u32 = IP */ 59 O_IP_DST_MASK, /* ip = IP/mask */ 60 O_IP_DST_ME, /* none */ 61 O_IP_DST_SET, /* u32=base, arg1=len, bitmap */ 62 63 O_IP_SRCPORT, /* (n)port list:mask 4 byte ea */ 64 O_IP_DSTPORT, /* (n)port list:mask 4 byte ea */ 65 O_PROTO, /* arg1=protocol */ 66 67 O_MACADDR2, /* 2 mac addr:mask */ 68 O_MAC_TYPE, /* same as srcport */ 69 70 O_LAYER2, /* none */ 71 O_IN, /* none */ 72 O_FRAG, /* none */ 73 74 O_RECV, /* none */ 75 O_XMIT, /* none */ 76 O_VIA, /* none */ 77 78 O_IPOPT, /* arg1 = 2*u8 bitmap */ 79 O_IPLEN, /* arg1 = len */ 80 O_IPID, /* arg1 = id */ 81 82 O_IPTOS, /* arg1 = id */ 83 O_IPPRECEDENCE, /* arg1 = precedence << 5 */ 84 O_IPTTL, /* arg1 = TTL */ 85 86 O_IPVER, /* arg1 = version */ 87 O_UID, /* u32 = id */ 88 O_GID, /* u32 = id */ 89 O_ESTAB, /* none (tcp established) */ 90 O_TCPFLAGS, /* arg1 = 2*u8 bitmap */ 91 O_TCPWIN, /* arg1 = desired win */ 92 O_TCPSEQ, /* u32 = desired seq. */ 93 O_TCPACK, /* u32 = desired seq. */ 94 O_ICMPTYPE, /* u32 = icmp bitmap */ 95 O_TCPOPTS, /* arg1 = 2*u8 bitmap */ 96 97 O_VERREVPATH, /* none */ 98 O_VERSRCREACH, /* none */ 99 100 O_PROBE_STATE, /* none */ 101 O_KEEP_STATE, /* none */ 102 O_LIMIT, /* ipfw_insn_limit */ 103 O_LIMIT_PARENT, /* dyn_type, not an opcode. */ 104 105 /* 106 * These are really 'actions'. 107 */ 108 109 O_LOG, /* ipfw_insn_log */ 110 O_PROB, /* u32 = match probability */ 111 112 O_CHECK_STATE, /* none */ 113 O_ACCEPT, /* none */ 114 O_DENY, /* none */ 115 O_REJECT, /* arg1=icmp arg (same as deny) */ 116 O_COUNT, /* none */ 117 O_SKIPTO, /* arg1=next rule number */ 118 O_PIPE, /* arg1=pipe number */ 119 O_QUEUE, /* arg1=queue number */ 120 O_DIVERT, /* arg1=port number */ 121 O_TEE, /* arg1=port number */ 122 O_FORWARD_IP, /* fwd sockaddr */ 123 O_FORWARD_MAC, /* fwd mac */ 124 125 /* 126 * More opcodes. 127 */ 128 O_IPSEC, /* has ipsec history */ 129 O_IP_SRC_LOOKUP, /* arg1=table number, u32=value */ 130 O_IP_DST_LOOKUP, /* arg1=table number, u32=value */ 131 132 O_LAST_OPCODE /* not an opcode! */ 133 }; 134 135 /* 136 * Template for instructions. 137 * 138 * ipfw_insn is used for all instructions which require no operands, 139 * a single 16-bit value (arg1), or a couple of 8-bit values. 140 * 141 * For other instructions which require different/larger arguments 142 * we have derived structures, ipfw_insn_*. 143 * 144 * The size of the instruction (in 32-bit words) is in the low 145 * 6 bits of "len". The 2 remaining bits are used to implement 146 * NOT and OR on individual instructions. Given a type, you can 147 * compute the length to be put in "len" using F_INSN_SIZE(t) 148 * 149 * F_NOT negates the match result of the instruction. 150 * 151 * F_OR is used to build or blocks. By default, instructions 152 * are evaluated as part of a logical AND. An "or" block 153 * { X or Y or Z } contains F_OR set in all but the last 154 * instruction of the block. A match will cause the code 155 * to skip past the last instruction of the block. 156 * 157 * NOTA BENE: in a couple of places we assume that 158 * sizeof(ipfw_insn) == sizeof(u_int32_t) 159 * this needs to be fixed. 160 * 161 */ 162 typedef struct _ipfw_insn { /* template for instructions */ 163 enum ipfw_opcodes opcode:8; 164 u_int8_t len; /* numer of 32-byte words */ 165 #define F_NOT 0x80 166 #define F_OR 0x40 167 #define F_LEN_MASK 0x3f 168 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK) 169 170 u_int16_t arg1; 171 } ipfw_insn; 172 173 /* 174 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of 175 * a given type. 176 */ 177 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t)) 178 179 /* 180 * This is used to store an array of 16-bit entries (ports etc.) 181 */ 182 typedef struct _ipfw_insn_u16 { 183 ipfw_insn o; 184 u_int16_t ports[2]; /* there may be more */ 185 } ipfw_insn_u16; 186 187 /* 188 * This is used to store an array of 32-bit entries 189 * (uid, single IPv4 addresses etc.) 190 */ 191 typedef struct _ipfw_insn_u32 { 192 ipfw_insn o; 193 u_int32_t d[1]; /* one or more */ 194 } ipfw_insn_u32; 195 196 /* 197 * This is used to store IP addr-mask pairs. 198 */ 199 typedef struct _ipfw_insn_ip { 200 ipfw_insn o; 201 struct in_addr addr; 202 struct in_addr mask; 203 } ipfw_insn_ip; 204 205 /* 206 * This is used to forward to a given address (ip). 207 */ 208 typedef struct _ipfw_insn_sa { 209 ipfw_insn o; 210 struct sockaddr_in sa; 211 } ipfw_insn_sa; 212 213 /* 214 * This is used for MAC addr-mask pairs. 215 */ 216 typedef struct _ipfw_insn_mac { 217 ipfw_insn o; 218 u_char addr[12]; /* dst[6] + src[6] */ 219 u_char mask[12]; /* dst[6] + src[6] */ 220 } ipfw_insn_mac; 221 222 /* 223 * This is used for interface match rules (recv xx, xmit xx). 224 */ 225 typedef struct _ipfw_insn_if { 226 ipfw_insn o; 227 union { 228 struct in_addr ip; 229 int glob; 230 } p; 231 char name[IFNAMSIZ]; 232 } ipfw_insn_if; 233 234 /* 235 * This is used for pipe and queue actions, which need to store 236 * a single pointer (which can have different size on different 237 * architectures. 238 * Note that, because of previous instructions, pipe_ptr might 239 * be unaligned in the overall structure, so it needs to be 240 * manipulated with care. 241 */ 242 typedef struct _ipfw_insn_pipe { 243 ipfw_insn o; 244 void *pipe_ptr; /* XXX */ 245 } ipfw_insn_pipe; 246 247 /* 248 * This is used for limit rules. 249 */ 250 typedef struct _ipfw_insn_limit { 251 ipfw_insn o; 252 u_int8_t _pad; 253 u_int8_t limit_mask; /* combination of DYN_* below */ 254 #define DYN_SRC_ADDR 0x1 255 #define DYN_SRC_PORT 0x2 256 #define DYN_DST_ADDR 0x4 257 #define DYN_DST_PORT 0x8 258 259 u_int16_t conn_limit; 260 } ipfw_insn_limit; 261 262 /* 263 * This is used for log instructions. 264 */ 265 typedef struct _ipfw_insn_log { 266 ipfw_insn o; 267 u_int32_t max_log; /* how many do we log -- 0 = all */ 268 u_int32_t log_left; /* how many left to log */ 269 } ipfw_insn_log; 270 271 /* 272 * Here we have the structure representing an ipfw rule. 273 * 274 * It starts with a general area (with link fields and counters) 275 * followed by an array of one or more instructions, which the code 276 * accesses as an array of 32-bit values. 277 * 278 * Given a rule pointer r: 279 * 280 * r->cmd is the start of the first instruction. 281 * ACTION_PTR(r) is the start of the first action (things to do 282 * once a rule matched). 283 * 284 * When assembling instruction, remember the following: 285 * 286 * + if a rule has a "keep-state" (or "limit") option, then the 287 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE 288 * + if a rule has a "log" option, then the first action 289 * (at ACTION_PTR(r)) MUST be O_LOG 290 * 291 * NOTE: we use a simple linked list of rules because we never need 292 * to delete a rule without scanning the list. We do not use 293 * queue(3) macros for portability and readability. 294 */ 295 296 struct ip_fw { 297 struct ip_fw *next; /* linked list of rules */ 298 struct ip_fw *next_rule; /* ptr to next [skipto] rule */ 299 /* 'next_rule' is used to pass up 'set_disable' status */ 300 301 u_int16_t act_ofs; /* offset of action in 32-bit units */ 302 u_int16_t cmd_len; /* # of 32-bit words in cmd */ 303 u_int16_t rulenum; /* rule number */ 304 u_int8_t set; /* rule set (0..31) */ 305 #define RESVD_SET 31 /* set for default and persistent rules */ 306 u_int8_t _pad; /* padding */ 307 308 /* These fields are present in all rules. */ 309 u_int64_t pcnt; /* Packet counter */ 310 u_int64_t bcnt; /* Byte counter */ 311 u_int32_t timestamp; /* tv_sec of last match */ 312 313 ipfw_insn cmd[1]; /* storage for commands */ 314 }; 315 316 #define ACTION_PTR(rule) \ 317 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) ) 318 319 #define RULESIZE(rule) (sizeof(struct ip_fw) + \ 320 ((struct ip_fw *)(rule))->cmd_len * 4 - 4) 321 322 /* 323 * This structure is used as a flow mask and a flow id for various 324 * parts of the code. 325 */ 326 struct ipfw_flow_id { 327 u_int32_t dst_ip; 328 u_int32_t src_ip; 329 u_int16_t dst_port; 330 u_int16_t src_port; 331 u_int8_t proto; 332 u_int8_t flags; /* protocol-specific flags */ 333 }; 334 335 /* 336 * Dynamic ipfw rule. 337 */ 338 typedef struct _ipfw_dyn_rule ipfw_dyn_rule; 339 340 struct _ipfw_dyn_rule { 341 ipfw_dyn_rule *next; /* linked list of rules. */ 342 struct ip_fw *rule; /* pointer to rule */ 343 /* 'rule' is used to pass up the rule number (from the parent) */ 344 345 ipfw_dyn_rule *parent; /* pointer to parent rule */ 346 u_int64_t pcnt; /* packet match counter */ 347 u_int64_t bcnt; /* byte match counter */ 348 struct ipfw_flow_id id; /* (masked) flow id */ 349 u_int32_t expire; /* expire time */ 350 u_int32_t bucket; /* which bucket in hash table */ 351 u_int32_t state; /* state of this rule (typically a 352 * combination of TCP flags) 353 */ 354 u_int32_t ack_fwd; /* most recent ACKs in forward */ 355 u_int32_t ack_rev; /* and reverse directions (used */ 356 /* to generate keepalives) */ 357 u_int16_t dyn_type; /* rule type */ 358 u_int16_t count; /* refcount */ 359 }; 360 361 /* 362 * Definitions for IP option names. 363 */ 364 #define IP_FW_IPOPT_LSRR 0x01 365 #define IP_FW_IPOPT_SSRR 0x02 366 #define IP_FW_IPOPT_RR 0x04 367 #define IP_FW_IPOPT_TS 0x08 368 369 /* 370 * Definitions for TCP option names. 371 */ 372 #define IP_FW_TCPOPT_MSS 0x01 373 #define IP_FW_TCPOPT_WINDOW 0x02 374 #define IP_FW_TCPOPT_SACK 0x04 375 #define IP_FW_TCPOPT_TS 0x08 376 #define IP_FW_TCPOPT_CC 0x10 377 378 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */ 379 380 /* 381 * These are used for lookup tables. 382 */ 383 typedef struct _ipfw_table_entry { 384 in_addr_t addr; /* network address */ 385 u_int32_t value; /* value */ 386 u_int16_t tbl; /* table number */ 387 u_int8_t masklen; /* mask length */ 388 } ipfw_table_entry; 389 390 typedef struct _ipfw_table { 391 u_int32_t size; /* size of entries in bytes */ 392 u_int32_t cnt; /* # of entries */ 393 u_int16_t tbl; /* table number */ 394 ipfw_table_entry ent[0]; /* entries */ 395 } ipfw_table; 396 397 /* 398 * Main firewall chains definitions and global var's definitions. 399 */ 400 #ifdef _KERNEL 401 402 #define IP_FW_PORT_DYNT_FLAG 0x10000 403 #define IP_FW_PORT_TEE_FLAG 0x20000 404 #define IP_FW_PORT_DENY_FLAG 0x40000 405 406 /* 407 * Arguments for calling ipfw_chk() and dummynet_io(). We put them 408 * all into a structure because this way it is easier and more 409 * efficient to pass variables around and extend the interface. 410 */ 411 struct ip_fw_args { 412 struct mbuf *m; /* the mbuf chain */ 413 struct ifnet *oif; /* output interface */ 414 struct sockaddr_in *next_hop; /* forward address */ 415 struct ip_fw *rule; /* matching rule */ 416 struct ether_header *eh; /* for bridged packets */ 417 418 struct route *ro; /* for dummynet */ 419 struct sockaddr_in *dst; /* for dummynet */ 420 int flags; /* for dummynet */ 421 422 struct ipfw_flow_id f_id; /* grabbed from IP header */ 423 u_int32_t retval; 424 }; 425 426 /* 427 * Function definitions. 428 */ 429 430 /* Firewall hooks */ 431 struct sockopt; 432 struct dn_flow_set; 433 434 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */ 435 436 typedef int ip_fw_chk_t (struct ip_fw_args *args); 437 typedef int ip_fw_ctl_t (struct sockopt *); 438 extern ip_fw_chk_t *ip_fw_chk_ptr; 439 extern ip_fw_ctl_t *ip_fw_ctl_ptr; 440 extern int fw_one_pass; 441 extern int fw_enable; 442 #define IPFW_LOADED (ip_fw_chk_ptr != NULL) 443 #endif /* _KERNEL */ 444 445 #endif /* _IPFW2_H */ 446