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 * these are really 'actions', and must be last in the list. 105 */ 106 107 O_LOG, /* ipfw_insn_log */ 108 O_PROB, /* u32 = match probability */ 109 110 O_CHECK_STATE, /* none */ 111 O_ACCEPT, /* none */ 112 O_DENY, /* none */ 113 O_REJECT, /* arg1=icmp arg (same as deny) */ 114 O_COUNT, /* none */ 115 O_SKIPTO, /* arg1=next rule number */ 116 O_PIPE, /* arg1=pipe number */ 117 O_QUEUE, /* arg1=queue number */ 118 O_DIVERT, /* arg1=port number */ 119 O_TEE, /* arg1=port number */ 120 O_FORWARD_IP, /* fwd sockaddr */ 121 O_FORWARD_MAC, /* fwd mac */ 122 O_LAST_OPCODE /* not an opcode! */ 123 }; 124 125 /* 126 * Template for instructions. 127 * 128 * ipfw_insn is used for all instructions which require no operands, 129 * a single 16-bit value (arg1), or a couple of 8-bit values. 130 * 131 * For other instructions which require different/larger arguments 132 * we have derived structures, ipfw_insn_*. 133 * 134 * The size of the instruction (in 32-bit words) is in the low 135 * 6 bits of "len". The 2 remaining bits are used to implement 136 * NOT and OR on individual instructions. Given a type, you can 137 * compute the length to be put in "len" using F_INSN_SIZE(t) 138 * 139 * F_NOT negates the match result of the instruction. 140 * 141 * F_OR is used to build or blocks. By default, instructions 142 * are evaluated as part of a logical AND. An "or" block 143 * { X or Y or Z } contains F_OR set in all but the last 144 * instruction of the block. A match will cause the code 145 * to skip past the last instruction of the block. 146 * 147 * NOTA BENE: in a couple of places we assume that 148 * sizeof(ipfw_insn) == sizeof(u_int32_t) 149 * this needs to be fixed. 150 * 151 */ 152 typedef struct _ipfw_insn { /* template for instructions */ 153 enum ipfw_opcodes opcode:8; 154 u_int8_t len; /* numer of 32-byte words */ 155 #define F_NOT 0x80 156 #define F_OR 0x40 157 #define F_LEN_MASK 0x3f 158 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK) 159 160 u_int16_t arg1; 161 } ipfw_insn; 162 163 /* 164 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of 165 * a given type. 166 */ 167 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t)) 168 169 /* 170 * This is used to store an array of 16-bit entries (ports etc.) 171 */ 172 typedef struct _ipfw_insn_u16 { 173 ipfw_insn o; 174 u_int16_t ports[2]; /* there may be more */ 175 } ipfw_insn_u16; 176 177 /* 178 * This is used to store an array of 32-bit entries 179 * (uid, single IPv4 addresses etc.) 180 */ 181 typedef struct _ipfw_insn_u32 { 182 ipfw_insn o; 183 u_int32_t d[1]; /* one or more */ 184 } ipfw_insn_u32; 185 186 /* 187 * This is used to store IP addr-mask pairs. 188 */ 189 typedef struct _ipfw_insn_ip { 190 ipfw_insn o; 191 struct in_addr addr; 192 struct in_addr mask; 193 } ipfw_insn_ip; 194 195 /* 196 * This is used to forward to a given address (ip) 197 */ 198 typedef struct _ipfw_insn_sa { 199 ipfw_insn o; 200 struct sockaddr_in sa; 201 } ipfw_insn_sa; 202 203 /* 204 * This is used for MAC addr-mask pairs. 205 */ 206 typedef struct _ipfw_insn_mac { 207 ipfw_insn o; 208 u_char addr[12]; /* dst[6] + src[6] */ 209 u_char mask[12]; /* dst[6] + src[6] */ 210 } ipfw_insn_mac; 211 212 /* 213 * This is used for interface match rules (recv xx, xmit xx) 214 */ 215 typedef struct _ipfw_insn_if { 216 ipfw_insn o; 217 union { 218 struct in_addr ip; 219 int32_t unit; 220 } p; 221 char name[IFNAMSIZ]; 222 } ipfw_insn_if; 223 224 /* 225 * This is used for pipe and queue actions, which need to store 226 * a single pointer (which can have different size on different 227 * architectures. 228 * Note that, because of previous instructions, pipe_ptr might 229 * be unaligned in the overall structure, so it needs to be 230 * manipulated with care. 231 */ 232 typedef struct _ipfw_insn_pipe { 233 ipfw_insn o; 234 void *pipe_ptr; /* XXX */ 235 } ipfw_insn_pipe; 236 237 /* 238 * This is used for limit rules. 239 */ 240 typedef struct _ipfw_insn_limit { 241 ipfw_insn o; 242 u_int8_t _pad; 243 u_int8_t limit_mask; /* combination of DYN_* below */ 244 #define DYN_SRC_ADDR 0x1 245 #define DYN_SRC_PORT 0x2 246 #define DYN_DST_ADDR 0x4 247 #define DYN_DST_PORT 0x8 248 249 u_int16_t conn_limit; 250 } ipfw_insn_limit; 251 252 /* 253 * This is used for log instructions 254 */ 255 typedef struct _ipfw_insn_log { 256 ipfw_insn o; 257 u_int32_t max_log; /* how many do we log -- 0 = all */ 258 u_int32_t log_left; /* how many left to log */ 259 } ipfw_insn_log; 260 261 /* 262 * Here we have the structure representing an ipfw rule. 263 * 264 * It starts with a general area (with link fields and counters) 265 * followed by an array of one or more instructions, which the code 266 * accesses as an array of 32-bit values. 267 * 268 * Given a rule pointer r: 269 * 270 * r->cmd is the start of the first instruction. 271 * ACTION_PTR(r) is the start of the first action (things to do 272 * once a rule matched). 273 * 274 * When assembling instruction, remember the following: 275 * 276 * + if a rule has a "keep-state" (or "limit") option, then the 277 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE 278 * + if a rule has a "log" option, then the first action 279 * (at ACTION_PTR(r)) MUST be O_LOG 280 * 281 * NOTE: we use a simple linked list of rules because we never need 282 * to delete a rule without scanning the list. We do not use 283 * queue(3) macros for portability and readability. 284 */ 285 286 struct ip_fw { 287 struct ip_fw *next; /* linked list of rules */ 288 struct ip_fw *next_rule; /* ptr to next [skipto] rule */ 289 #if 0 /* passed up using 'next_rule' */ 290 u_int32_t set_disable; /* disabled sets (for userland) */ 291 #endif 292 u_int16_t act_ofs; /* offset of action in 32-bit units */ 293 u_int16_t cmd_len; /* # of 32-bit words in cmd */ 294 u_int16_t rulenum; /* rule number */ 295 u_int8_t set; /* rule set (0..31) */ 296 u_int8_t _pad; /* padding */ 297 298 /* These fields are present in all rules. */ 299 u_int64_t pcnt; /* Packet counter */ 300 u_int64_t bcnt; /* Byte counter */ 301 u_int32_t timestamp; /* tv_sec of last match */ 302 303 ipfw_insn cmd[1]; /* storage for commands */ 304 }; 305 306 #define ACTION_PTR(rule) \ 307 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) ) 308 309 #define RULESIZE(rule) (sizeof(struct ip_fw) + \ 310 ((struct ip_fw *)(rule))->cmd_len * 4 - 4) 311 312 /* 313 * This structure is used as a flow mask and a flow id for various 314 * parts of the code. 315 */ 316 struct ipfw_flow_id { 317 u_int32_t dst_ip; 318 u_int32_t src_ip; 319 u_int16_t dst_port; 320 u_int16_t src_port; 321 u_int8_t proto; 322 u_int8_t flags; /* protocol-specific flags */ 323 }; 324 325 /* 326 * dynamic ipfw rule 327 */ 328 typedef struct _ipfw_dyn_rule ipfw_dyn_rule; 329 330 struct _ipfw_dyn_rule { 331 ipfw_dyn_rule *next; /* linked list of rules. */ 332 struct ip_fw *rule; /* pointer to rule */ 333 ipfw_dyn_rule *parent; /* pointer to parent rule */ 334 u_int64_t pcnt; /* packet match counter */ 335 u_int64_t bcnt; /* byte match counter */ 336 struct ipfw_flow_id id; /* (masked) flow id */ 337 u_int32_t expire; /* expire time */ 338 u_int32_t bucket; /* which bucket in hash table */ 339 u_int32_t state; /* state of this rule (typically a 340 * combination of TCP flags) 341 */ 342 u_int32_t ack_fwd; /* most recent ACKs in forward */ 343 u_int32_t ack_rev; /* and reverse directions (used */ 344 /* to generate keepalives) */ 345 u_int16_t dyn_type; /* rule type */ 346 u_int16_t count; /* refcount */ 347 #if 0 /* passed up with 'rule' */ 348 u_int16_t rulenum; /* rule number (for userland) */ 349 #endif 350 }; 351 352 /* 353 * Definitions for IP option names. 354 */ 355 #define IP_FW_IPOPT_LSRR 0x01 356 #define IP_FW_IPOPT_SSRR 0x02 357 #define IP_FW_IPOPT_RR 0x04 358 #define IP_FW_IPOPT_TS 0x08 359 360 /* 361 * Definitions for TCP option names. 362 */ 363 #define IP_FW_TCPOPT_MSS 0x01 364 #define IP_FW_TCPOPT_WINDOW 0x02 365 #define IP_FW_TCPOPT_SACK 0x04 366 #define IP_FW_TCPOPT_TS 0x08 367 #define IP_FW_TCPOPT_CC 0x10 368 369 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */ 370 371 /* 372 * Main firewall chains definitions and global var's definitions. 373 */ 374 #ifdef _KERNEL 375 376 #define IP_FW_PORT_DYNT_FLAG 0x10000 377 #define IP_FW_PORT_TEE_FLAG 0x20000 378 #define IP_FW_PORT_DENY_FLAG 0x40000 379 380 /* 381 * arguments for calling ipfw_chk() and dummynet_io(). We put them 382 * all into a structure because this way it is easier and more 383 * efficient to pass variables around and extend the interface. 384 */ 385 struct ip_fw_args { 386 struct mbuf *m; /* the mbuf chain */ 387 struct ifnet *oif; /* output interface */ 388 struct sockaddr_in *next_hop; /* forward address */ 389 struct ip_fw *rule; /* matching rule */ 390 struct ether_header *eh; /* for bridged packets */ 391 392 struct route *ro; /* for dummynet */ 393 struct sockaddr_in *dst; /* for dummynet */ 394 int flags; /* for dummynet */ 395 396 struct ipfw_flow_id f_id; /* grabbed from IP header */ 397 u_int16_t divert_rule; /* divert cookie */ 398 u_int32_t retval; 399 }; 400 401 /* 402 * Function definitions. 403 */ 404 405 /* Firewall hooks */ 406 struct sockopt; 407 struct dn_flow_set; 408 409 void flush_pipe_ptrs(struct dn_flow_set *match); /* used by dummynet */ 410 411 typedef int ip_fw_chk_t (struct ip_fw_args *args); 412 typedef int ip_fw_ctl_t (struct sockopt *); 413 extern ip_fw_chk_t *ip_fw_chk_ptr; 414 extern ip_fw_ctl_t *ip_fw_ctl_ptr; 415 extern int fw_one_pass; 416 extern int fw_enable; 417 #define IPFW_LOADED (ip_fw_chk_ptr != NULL) 418 #endif /* _KERNEL */ 419 420 #endif /* _IPFW2_H */ 421