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 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 */ 102 103 O_PROBE_STATE, /* none */ 104 O_KEEP_STATE, /* none */ 105 O_LIMIT, /* ipfw_insn_limit */ 106 O_LIMIT_PARENT, /* dyn_type, not an opcode. */ 107 108 /* 109 * These are really 'actions'. 110 */ 111 112 O_LOG, /* ipfw_insn_log */ 113 O_PROB, /* u32 = match probability */ 114 115 O_CHECK_STATE, /* none */ 116 O_ACCEPT, /* none */ 117 O_DENY, /* none */ 118 O_REJECT, /* arg1=icmp arg (same as deny) */ 119 O_COUNT, /* none */ 120 O_SKIPTO, /* arg1=next rule number */ 121 O_PIPE, /* arg1=pipe number */ 122 O_QUEUE, /* arg1=queue number */ 123 O_DIVERT, /* arg1=port number */ 124 O_TEE, /* arg1=port number */ 125 O_FORWARD_IP, /* fwd sockaddr */ 126 O_FORWARD_MAC, /* fwd mac */ 127 O_NAT, /* nope */ 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 O_IP6_SRC, /* address without mask */ 141 O_IP6_SRC_ME, /* my addresses */ 142 O_IP6_SRC_MASK, /* address with the mask */ 143 O_IP6_DST, 144 O_IP6_DST_ME, 145 O_IP6_DST_MASK, 146 O_FLOW6ID, /* for flow id tag in the ipv6 pkt */ 147 O_ICMP6TYPE, /* icmp6 packet type filtering */ 148 O_EXT_HDR, /* filtering for ipv6 extension header */ 149 O_IP6, 150 151 /* 152 * actions for ng_ipfw 153 */ 154 O_NETGRAPH, /* send to ng_ipfw */ 155 O_NGTEE, /* copy to ng_ipfw */ 156 157 O_IP4, 158 159 O_UNREACH6, /* arg1=icmpv6 code arg (deny) */ 160 161 O_TAG, /* arg1=tag number */ 162 O_TAGGED, /* arg1=tag number */ 163 164 O_LAST_OPCODE /* not an opcode! */ 165 }; 166 167 /* 168 * The extension header are filtered only for presence using a bit 169 * vector with a flag for each header. 170 */ 171 #define EXT_FRAGMENT 0x1 172 #define EXT_HOPOPTS 0x2 173 #define EXT_ROUTING 0x4 174 #define EXT_AH 0x8 175 #define EXT_ESP 0x10 176 #define EXT_DSTOPTS 0x20 177 #define EXT_RTHDR0 0x40 178 #define EXT_RTHDR2 0x80 179 180 /* 181 * Template for instructions. 182 * 183 * ipfw_insn is used for all instructions which require no operands, 184 * a single 16-bit value (arg1), or a couple of 8-bit values. 185 * 186 * For other instructions which require different/larger arguments 187 * we have derived structures, ipfw_insn_*. 188 * 189 * The size of the instruction (in 32-bit words) is in the low 190 * 6 bits of "len". The 2 remaining bits are used to implement 191 * NOT and OR on individual instructions. Given a type, you can 192 * compute the length to be put in "len" using F_INSN_SIZE(t) 193 * 194 * F_NOT negates the match result of the instruction. 195 * 196 * F_OR is used to build or blocks. By default, instructions 197 * are evaluated as part of a logical AND. An "or" block 198 * { X or Y or Z } contains F_OR set in all but the last 199 * instruction of the block. A match will cause the code 200 * to skip past the last instruction of the block. 201 * 202 * NOTA BENE: in a couple of places we assume that 203 * sizeof(ipfw_insn) == sizeof(u_int32_t) 204 * this needs to be fixed. 205 * 206 */ 207 typedef struct _ipfw_insn { /* template for instructions */ 208 enum ipfw_opcodes opcode:8; 209 u_int8_t len; /* numer of 32-byte words */ 210 #define F_NOT 0x80 211 #define F_OR 0x40 212 #define F_LEN_MASK 0x3f 213 #define F_LEN(cmd) ((cmd)->len & F_LEN_MASK) 214 215 u_int16_t arg1; 216 } ipfw_insn; 217 218 /* 219 * The F_INSN_SIZE(type) computes the size, in 4-byte words, of 220 * a given type. 221 */ 222 #define F_INSN_SIZE(t) ((sizeof (t))/sizeof(u_int32_t)) 223 224 #define MTAG_IPFW 1148380143 /* IPFW-tagged cookie */ 225 226 /* 227 * This is used to store an array of 16-bit entries (ports etc.) 228 */ 229 typedef struct _ipfw_insn_u16 { 230 ipfw_insn o; 231 u_int16_t ports[2]; /* there may be more */ 232 } ipfw_insn_u16; 233 234 /* 235 * This is used to store an array of 32-bit entries 236 * (uid, single IPv4 addresses etc.) 237 */ 238 typedef struct _ipfw_insn_u32 { 239 ipfw_insn o; 240 u_int32_t d[1]; /* one or more */ 241 } ipfw_insn_u32; 242 243 /* 244 * This is used to store IP addr-mask pairs. 245 */ 246 typedef struct _ipfw_insn_ip { 247 ipfw_insn o; 248 struct in_addr addr; 249 struct in_addr mask; 250 } ipfw_insn_ip; 251 252 /* 253 * This is used to forward to a given address (ip). 254 */ 255 typedef struct _ipfw_insn_sa { 256 ipfw_insn o; 257 struct sockaddr_in sa; 258 } ipfw_insn_sa; 259 260 /* 261 * This is used for MAC addr-mask pairs. 262 */ 263 typedef struct _ipfw_insn_mac { 264 ipfw_insn o; 265 u_char addr[12]; /* dst[6] + src[6] */ 266 u_char mask[12]; /* dst[6] + src[6] */ 267 } ipfw_insn_mac; 268 269 /* 270 * This is used for interface match rules (recv xx, xmit xx). 271 */ 272 typedef struct _ipfw_insn_if { 273 ipfw_insn o; 274 union { 275 struct in_addr ip; 276 int glob; 277 } p; 278 char name[IFNAMSIZ]; 279 } ipfw_insn_if; 280 281 /* 282 * This is used for storing an altq queue id number. 283 */ 284 typedef struct _ipfw_insn_altq { 285 ipfw_insn o; 286 u_int32_t qid; 287 } ipfw_insn_altq; 288 289 /* 290 * This is used for limit rules. 291 */ 292 typedef struct _ipfw_insn_limit { 293 ipfw_insn o; 294 u_int8_t _pad; 295 u_int8_t limit_mask; /* combination of DYN_* below */ 296 #define DYN_SRC_ADDR 0x1 297 #define DYN_SRC_PORT 0x2 298 #define DYN_DST_ADDR 0x4 299 #define DYN_DST_PORT 0x8 300 301 u_int16_t conn_limit; 302 } ipfw_insn_limit; 303 304 /* 305 * This is used for log instructions. 306 */ 307 typedef struct _ipfw_insn_log { 308 ipfw_insn o; 309 u_int32_t max_log; /* how many do we log -- 0 = all */ 310 u_int32_t log_left; /* how many left to log */ 311 } ipfw_insn_log; 312 313 /* Server pool support (LSNAT). */ 314 struct cfg_spool { 315 LIST_ENTRY(cfg_spool) _next; /* chain of spool instances */ 316 struct in_addr addr; 317 u_short port; 318 }; 319 320 /* Redirect modes id. */ 321 #define REDIR_ADDR 0x01 322 #define REDIR_PORT 0x02 323 #define REDIR_PROTO 0x04 324 325 /* Nat redirect configuration. */ 326 struct cfg_redir { 327 LIST_ENTRY(cfg_redir) _next; /* chain of redir instances */ 328 u_int16_t mode; /* type of redirect mode */ 329 struct in_addr laddr; /* local ip address */ 330 struct in_addr paddr; /* public ip address */ 331 struct in_addr raddr; /* remote ip address */ 332 u_short lport; /* local port */ 333 u_short pport; /* public port */ 334 u_short rport; /* remote port */ 335 u_short pport_cnt; /* number of public ports */ 336 u_short rport_cnt; /* number of remote ports */ 337 int proto; /* protocol: tcp/udp */ 338 struct alias_link **alink; 339 /* num of entry in spool chain */ 340 u_int16_t spool_cnt; 341 /* chain of spool instances */ 342 LIST_HEAD(spool_chain, cfg_spool) spool_chain; 343 }; 344 345 #define NAT_BUF_LEN 1024 346 /* Nat configuration data struct. */ 347 struct cfg_nat { 348 /* chain of nat instances */ 349 LIST_ENTRY(cfg_nat) _next; 350 int id; /* nat id */ 351 struct in_addr ip; /* nat ip address */ 352 char if_name[IF_NAMESIZE]; /* interface name */ 353 int mode; /* aliasing mode */ 354 struct libalias *lib; /* libalias instance */ 355 /* number of entry in spool chain */ 356 int redir_cnt; 357 /* chain of redir instances */ 358 LIST_HEAD(redir_chain, cfg_redir) redir_chain; 359 }; 360 361 #define SOF_NAT sizeof(struct cfg_nat) 362 #define SOF_REDIR sizeof(struct cfg_redir) 363 #define SOF_SPOOL sizeof(struct cfg_spool) 364 365 /* Nat command. */ 366 typedef struct _ipfw_insn_nat { 367 ipfw_insn o; 368 struct cfg_nat *nat; 369 } ipfw_insn_nat; 370 371 /* Apply ipv6 mask on ipv6 addr */ 372 #define APPLY_MASK(addr,mask) \ 373 (addr)->__u6_addr.__u6_addr32[0] &= (mask)->__u6_addr.__u6_addr32[0]; \ 374 (addr)->__u6_addr.__u6_addr32[1] &= (mask)->__u6_addr.__u6_addr32[1]; \ 375 (addr)->__u6_addr.__u6_addr32[2] &= (mask)->__u6_addr.__u6_addr32[2]; \ 376 (addr)->__u6_addr.__u6_addr32[3] &= (mask)->__u6_addr.__u6_addr32[3]; 377 378 /* Structure for ipv6 */ 379 typedef struct _ipfw_insn_ip6 { 380 ipfw_insn o; 381 struct in6_addr addr6; 382 struct in6_addr mask6; 383 } ipfw_insn_ip6; 384 385 /* Used to support icmp6 types */ 386 typedef struct _ipfw_insn_icmp6 { 387 ipfw_insn o; 388 uint32_t d[7]; /* XXX This number si related to the netinet/icmp6.h 389 * define ICMP6_MAXTYPE 390 * as follows: n = ICMP6_MAXTYPE/32 + 1 391 * Actually is 203 392 */ 393 } ipfw_insn_icmp6; 394 395 /* 396 * Here we have the structure representing an ipfw rule. 397 * 398 * It starts with a general area (with link fields and counters) 399 * followed by an array of one or more instructions, which the code 400 * accesses as an array of 32-bit values. 401 * 402 * Given a rule pointer r: 403 * 404 * r->cmd is the start of the first instruction. 405 * ACTION_PTR(r) is the start of the first action (things to do 406 * once a rule matched). 407 * 408 * When assembling instruction, remember the following: 409 * 410 * + if a rule has a "keep-state" (or "limit") option, then the 411 * first instruction (at r->cmd) MUST BE an O_PROBE_STATE 412 * + if a rule has a "log" option, then the first action 413 * (at ACTION_PTR(r)) MUST be O_LOG 414 * + if a rule has an "altq" option, it comes after "log" 415 * + if a rule has an O_TAG option, it comes after "log" and "altq" 416 * 417 * NOTE: we use a simple linked list of rules because we never need 418 * to delete a rule without scanning the list. We do not use 419 * queue(3) macros for portability and readability. 420 */ 421 422 struct ip_fw { 423 struct ip_fw *next; /* linked list of rules */ 424 struct ip_fw *next_rule; /* ptr to next [skipto] rule */ 425 /* 'next_rule' is used to pass up 'set_disable' status */ 426 427 u_int16_t act_ofs; /* offset of action in 32-bit units */ 428 u_int16_t cmd_len; /* # of 32-bit words in cmd */ 429 u_int16_t rulenum; /* rule number */ 430 u_int8_t set; /* rule set (0..31) */ 431 #define RESVD_SET 31 /* set for default and persistent rules */ 432 u_int8_t _pad; /* padding */ 433 434 /* These fields are present in all rules. */ 435 u_int64_t pcnt; /* Packet counter */ 436 u_int64_t bcnt; /* Byte counter */ 437 u_int32_t timestamp; /* tv_sec of last match */ 438 439 ipfw_insn cmd[1]; /* storage for commands */ 440 }; 441 442 #define ACTION_PTR(rule) \ 443 (ipfw_insn *)( (u_int32_t *)((rule)->cmd) + ((rule)->act_ofs) ) 444 445 #define RULESIZE(rule) (sizeof(struct ip_fw) + \ 446 ((struct ip_fw *)(rule))->cmd_len * 4 - 4) 447 448 /* 449 * This structure is used as a flow mask and a flow id for various 450 * parts of the code. 451 */ 452 struct ipfw_flow_id { 453 u_int32_t dst_ip; 454 u_int32_t src_ip; 455 u_int16_t dst_port; 456 u_int16_t src_port; 457 u_int8_t proto; 458 u_int8_t flags; /* protocol-specific flags */ 459 uint8_t addr_type; /* 4 = ipv4, 6 = ipv6, 1=ether ? */ 460 struct in6_addr dst_ip6; /* could also store MAC addr! */ 461 struct in6_addr src_ip6; 462 u_int32_t flow_id6; 463 u_int32_t frag_id6; 464 }; 465 466 #define IS_IP6_FLOW_ID(id) ((id)->addr_type == 6) 467 468 /* 469 * Dynamic ipfw rule. 470 */ 471 typedef struct _ipfw_dyn_rule ipfw_dyn_rule; 472 473 struct _ipfw_dyn_rule { 474 ipfw_dyn_rule *next; /* linked list of rules. */ 475 struct ip_fw *rule; /* pointer to rule */ 476 /* 'rule' is used to pass up the rule number (from the parent) */ 477 478 ipfw_dyn_rule *parent; /* pointer to parent rule */ 479 u_int64_t pcnt; /* packet match counter */ 480 u_int64_t bcnt; /* byte match counter */ 481 struct ipfw_flow_id id; /* (masked) flow id */ 482 u_int32_t expire; /* expire time */ 483 u_int32_t bucket; /* which bucket in hash table */ 484 u_int32_t state; /* state of this rule (typically a 485 * combination of TCP flags) 486 */ 487 u_int32_t ack_fwd; /* most recent ACKs in forward */ 488 u_int32_t ack_rev; /* and reverse directions (used */ 489 /* to generate keepalives) */ 490 u_int16_t dyn_type; /* rule type */ 491 u_int16_t count; /* refcount */ 492 }; 493 494 /* 495 * Definitions for IP option names. 496 */ 497 #define IP_FW_IPOPT_LSRR 0x01 498 #define IP_FW_IPOPT_SSRR 0x02 499 #define IP_FW_IPOPT_RR 0x04 500 #define IP_FW_IPOPT_TS 0x08 501 502 /* 503 * Definitions for TCP option names. 504 */ 505 #define IP_FW_TCPOPT_MSS 0x01 506 #define IP_FW_TCPOPT_WINDOW 0x02 507 #define IP_FW_TCPOPT_SACK 0x04 508 #define IP_FW_TCPOPT_TS 0x08 509 #define IP_FW_TCPOPT_CC 0x10 510 511 #define ICMP_REJECT_RST 0x100 /* fake ICMP code (send a TCP RST) */ 512 #define ICMP6_UNREACH_RST 0x100 /* fake ICMPv6 code (send a TCP RST) */ 513 514 /* 515 * These are used for lookup tables. 516 */ 517 typedef struct _ipfw_table_entry { 518 in_addr_t addr; /* network address */ 519 u_int32_t value; /* value */ 520 u_int16_t tbl; /* table number */ 521 u_int8_t masklen; /* mask length */ 522 } ipfw_table_entry; 523 524 typedef struct _ipfw_table { 525 u_int32_t size; /* size of entries in bytes */ 526 u_int32_t cnt; /* # of entries */ 527 u_int16_t tbl; /* table number */ 528 ipfw_table_entry ent[0]; /* entries */ 529 } ipfw_table; 530 531 #define IP_FW_TABLEARG 65535 532 533 /* 534 * Main firewall chains definitions and global var's definitions. 535 */ 536 #ifdef _KERNEL 537 538 /* Return values from ipfw_chk() */ 539 enum { 540 IP_FW_PASS = 0, 541 IP_FW_DENY, 542 IP_FW_DIVERT, 543 IP_FW_TEE, 544 IP_FW_DUMMYNET, 545 IP_FW_NETGRAPH, 546 IP_FW_NGTEE, 547 IP_FW_NAT, 548 }; 549 550 /* flags for divert mtag */ 551 #define IP_FW_DIVERT_LOOPBACK_FLAG 0x00080000 552 #define IP_FW_DIVERT_OUTPUT_FLAG 0x00100000 553 554 /* 555 * Structure for collecting parameters to dummynet for ip6_output forwarding 556 */ 557 struct _ip6dn_args { 558 struct ip6_pktopts *opt_or; 559 struct route_in6 ro_or; 560 int flags_or; 561 struct ip6_moptions *im6o_or; 562 struct ifnet *origifp_or; 563 struct ifnet *ifp_or; 564 struct sockaddr_in6 dst_or; 565 u_long mtu_or; 566 struct route_in6 ro_pmtu_or; 567 }; 568 569 /* 570 * Arguments for calling ipfw_chk() and dummynet_io(). We put them 571 * all into a structure because this way it is easier and more 572 * efficient to pass variables around and extend the interface. 573 */ 574 struct ip_fw_args { 575 struct mbuf *m; /* the mbuf chain */ 576 struct ifnet *oif; /* output interface */ 577 struct sockaddr_in *next_hop; /* forward address */ 578 struct ip_fw *rule; /* matching rule */ 579 struct ether_header *eh; /* for bridged packets */ 580 581 struct ipfw_flow_id f_id; /* grabbed from IP header */ 582 u_int32_t cookie; /* a cookie depending on rule action */ 583 struct inpcb *inp; 584 585 struct _ip6dn_args dummypar; /* dummynet->ip6_output */ 586 struct sockaddr_in hopstore; /* store here if cannot use a pointer */ 587 }; 588 589 /* 590 * Function definitions. 591 */ 592 593 /* Firewall hooks */ 594 struct sockopt; 595 struct dn_flow_set; 596 597 int ipfw_check_in(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 598 int ipfw_check_out(void *, struct mbuf **, struct ifnet *, int, struct inpcb *inp); 599 600 int ipfw_chk(struct ip_fw_args *); 601 602 int ipfw_init(void); 603 void ipfw_destroy(void); 604 605 typedef int ip_fw_ctl_t(struct sockopt *); 606 extern ip_fw_ctl_t *ip_fw_ctl_ptr; 607 extern int fw_one_pass; 608 extern int fw_enable; 609 #ifdef INET6 610 extern int fw6_enable; 611 #endif 612 613 /* For kernel ipfw_ether and ipfw_bridge. */ 614 typedef int ip_fw_chk_t(struct ip_fw_args *args); 615 extern ip_fw_chk_t *ip_fw_chk_ptr; 616 #define IPFW_LOADED (ip_fw_chk_ptr != NULL) 617 618 #endif /* _KERNEL */ 619 #endif /* _IPFW2_H */ 620