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