1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2004 Andre Oppermann, Internet Business Solutions AG 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_ipfw.h" 33 #include "opt_inet.h" 34 #include "opt_inet6.h" 35 #ifndef INET 36 #error IPFIREWALL requires INET. 37 #endif /* INET */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/malloc.h> 42 #include <sys/mbuf.h> 43 #include <sys/module.h> 44 #include <sys/kernel.h> 45 #include <sys/lock.h> 46 #include <sys/rwlock.h> 47 #include <sys/socket.h> 48 #include <sys/sysctl.h> 49 50 #include <net/if.h> 51 #include <net/if_var.h> 52 #include <net/route.h> 53 #include <net/ethernet.h> 54 #include <net/pfil.h> 55 #include <net/vnet.h> 56 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/ip.h> 60 #include <netinet/ip_var.h> 61 #include <netinet/ip_fw.h> 62 #ifdef INET6 63 #include <netinet/ip6.h> 64 #include <netinet6/ip6_var.h> 65 #include <netinet6/scope6_var.h> 66 #endif 67 68 #include <netgraph/ng_ipfw.h> 69 70 #include <netpfil/ipfw/ip_fw_private.h> 71 72 #include <machine/in_cksum.h> 73 74 VNET_DEFINE_STATIC(int, fw_enable) = 1; 75 #define V_fw_enable VNET(fw_enable) 76 77 #ifdef INET6 78 VNET_DEFINE_STATIC(int, fw6_enable) = 1; 79 #define V_fw6_enable VNET(fw6_enable) 80 #endif 81 82 VNET_DEFINE_STATIC(int, fwlink_enable) = 0; 83 #define V_fwlink_enable VNET(fwlink_enable) 84 85 int ipfw_chg_hook(SYSCTL_HANDLER_ARGS); 86 87 /* Forward declarations. */ 88 static int ipfw_divert(struct mbuf **, int, struct ipfw_rule_ref *, int); 89 90 #ifdef SYSCTL_NODE 91 92 SYSBEGIN(f1) 93 94 SYSCTL_DECL(_net_inet_ip_fw); 95 SYSCTL_PROC(_net_inet_ip_fw, OID_AUTO, enable, 96 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, 97 &VNET_NAME(fw_enable), 0, ipfw_chg_hook, "I", "Enable ipfw"); 98 #ifdef INET6 99 SYSCTL_DECL(_net_inet6_ip6_fw); 100 SYSCTL_PROC(_net_inet6_ip6_fw, OID_AUTO, enable, 101 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, 102 &VNET_NAME(fw6_enable), 0, ipfw_chg_hook, "I", "Enable ipfw+6"); 103 #endif /* INET6 */ 104 105 SYSCTL_DECL(_net_link_ether); 106 SYSCTL_PROC(_net_link_ether, OID_AUTO, ipfw, 107 CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE3, 108 &VNET_NAME(fwlink_enable), 0, ipfw_chg_hook, "I", 109 "Pass ether pkts through firewall"); 110 111 SYSEND 112 113 #endif /* SYSCTL_NODE */ 114 115 /* 116 * The pfilter hook to pass packets to ipfw_chk and then to 117 * dummynet, divert, netgraph or other modules. 118 * The packet may be consumed. 119 */ 120 static pfil_return_t 121 ipfw_check_packet(struct mbuf **m0, struct ifnet *ifp, int dir, 122 void *ruleset __unused, struct inpcb *inp) 123 { 124 struct ip_fw_args args; 125 struct m_tag *tag; 126 pfil_return_t ret; 127 int ipfw; 128 129 /* convert dir to IPFW values */ 130 dir = (dir & PFIL_IN) ? DIR_IN : DIR_OUT; 131 args.flags = 0; 132 again: 133 /* 134 * extract and remove the tag if present. If we are left 135 * with onepass, optimize the outgoing path. 136 */ 137 tag = m_tag_locate(*m0, MTAG_IPFW_RULE, 0, NULL); 138 if (tag != NULL) { 139 args.rule = *((struct ipfw_rule_ref *)(tag+1)); 140 m_tag_delete(*m0, tag); 141 if (args.rule.info & IPFW_ONEPASS) 142 return (0); 143 args.flags |= IPFW_ARGS_REF; 144 } 145 146 args.m = *m0; 147 args.oif = dir == DIR_OUT ? ifp : NULL; 148 args.inp = inp; 149 150 ipfw = ipfw_chk(&args); 151 *m0 = args.m; 152 153 KASSERT(*m0 != NULL || ipfw == IP_FW_DENY, ("%s: m0 is NULL", 154 __func__)); 155 156 ret = PFIL_PASS; 157 switch (ipfw) { 158 case IP_FW_PASS: 159 /* next_hop may be set by ipfw_chk */ 160 if ((args.flags & (IPFW_ARGS_NH4 | IPFW_ARGS_NH4PTR | 161 IPFW_ARGS_NH6 | IPFW_ARGS_NH6PTR)) == 0) 162 break; 163 #if (!defined(INET6) && !defined(INET)) 164 ret = PFIL_DROPPED; 165 #else 166 { 167 void *psa; 168 size_t len; 169 #ifdef INET 170 if (args.flags & (IPFW_ARGS_NH4 | IPFW_ARGS_NH4PTR)) { 171 MPASS((args.flags & (IPFW_ARGS_NH4 | 172 IPFW_ARGS_NH4PTR)) != (IPFW_ARGS_NH4 | 173 IPFW_ARGS_NH4PTR)); 174 MPASS((args.flags & (IPFW_ARGS_NH6 | 175 IPFW_ARGS_NH6PTR)) == 0); 176 len = sizeof(struct sockaddr_in); 177 psa = (args.flags & IPFW_ARGS_NH4) ? 178 &args.hopstore : args.next_hop; 179 if (in_localip(satosin(psa)->sin_addr)) 180 (*m0)->m_flags |= M_FASTFWD_OURS; 181 (*m0)->m_flags |= M_IP_NEXTHOP; 182 } 183 #endif /* INET */ 184 #ifdef INET6 185 if (args.flags & (IPFW_ARGS_NH6 | IPFW_ARGS_NH6PTR)) { 186 MPASS((args.flags & (IPFW_ARGS_NH6 | 187 IPFW_ARGS_NH6PTR)) != (IPFW_ARGS_NH6 | 188 IPFW_ARGS_NH6PTR)); 189 MPASS((args.flags & (IPFW_ARGS_NH4 | 190 IPFW_ARGS_NH4PTR)) == 0); 191 len = sizeof(struct sockaddr_in6); 192 psa = args.next_hop6; 193 (*m0)->m_flags |= M_IP6_NEXTHOP; 194 } 195 #endif /* INET6 */ 196 /* 197 * Incoming packets should not be tagged so we do not 198 * m_tag_find. Outgoing packets may be tagged, so we 199 * reuse the tag if present. 200 */ 201 tag = (dir == DIR_IN) ? NULL : 202 m_tag_find(*m0, PACKET_TAG_IPFORWARD, NULL); 203 if (tag != NULL) { 204 m_tag_unlink(*m0, tag); 205 } else { 206 tag = m_tag_get(PACKET_TAG_IPFORWARD, len, 207 M_NOWAIT); 208 if (tag == NULL) { 209 ret = PFIL_DROPPED; 210 break; 211 } 212 } 213 if ((args.flags & IPFW_ARGS_NH6) == 0) 214 bcopy(psa, tag + 1, len); 215 m_tag_prepend(*m0, tag); 216 ret = 0; 217 #ifdef INET6 218 /* IPv6 next hop needs additional handling */ 219 if (args.flags & (IPFW_ARGS_NH6 | IPFW_ARGS_NH6PTR)) { 220 struct sockaddr_in6 *sa6; 221 222 sa6 = satosin6(tag + 1); 223 if (args.flags & IPFW_ARGS_NH6) { 224 sa6->sin6_family = AF_INET6; 225 sa6->sin6_len = sizeof(*sa6); 226 sa6->sin6_addr = args.hopstore6.sin6_addr; 227 sa6->sin6_port = args.hopstore6.sin6_port; 228 sa6->sin6_scope_id = 229 args.hopstore6.sin6_scope_id; 230 } 231 /* 232 * If nh6 address is link-local we should convert 233 * it to kernel internal form before doing any 234 * comparisons. 235 */ 236 if (sa6_embedscope(sa6, V_ip6_use_defzone) != 0) { 237 ret = PFIL_DROPPED; 238 break; 239 } 240 if (in6_localip(&sa6->sin6_addr)) 241 (*m0)->m_flags |= M_FASTFWD_OURS; 242 } 243 #endif /* INET6 */ 244 } 245 #endif /* INET || INET6 */ 246 break; 247 248 case IP_FW_DENY: 249 ret = PFIL_DROPPED; 250 break; 251 252 case IP_FW_DUMMYNET: 253 if (ip_dn_io_ptr == NULL) { 254 ret = PFIL_DROPPED; 255 break; 256 } 257 MPASS(args.flags & IPFW_ARGS_REF); 258 if (mtod(*m0, struct ip *)->ip_v == 4) 259 (void )ip_dn_io_ptr(m0, dir, &args); 260 else if (mtod(*m0, struct ip *)->ip_v == 6) 261 (void )ip_dn_io_ptr(m0, dir | PROTO_IPV6, &args); 262 else { 263 ret = PFIL_DROPPED; 264 break; 265 } 266 /* 267 * XXX should read the return value. 268 * dummynet normally eats the packet and sets *m0=NULL 269 * unless the packet can be sent immediately. In this 270 * case args is updated and we should re-run the 271 * check without clearing args. 272 */ 273 if (*m0 != NULL) 274 goto again; 275 ret = PFIL_CONSUMED; 276 break; 277 278 case IP_FW_TEE: 279 case IP_FW_DIVERT: 280 if (ip_divert_ptr == NULL) { 281 ret = PFIL_DROPPED; 282 break; 283 } 284 MPASS(args.flags & IPFW_ARGS_REF); 285 (void )ipfw_divert(m0, dir, &args.rule, 286 (ipfw == IP_FW_TEE) ? 1 : 0); 287 /* continue processing for the original packet (tee). */ 288 if (*m0) 289 goto again; 290 ret = PFIL_CONSUMED; 291 break; 292 293 case IP_FW_NGTEE: 294 case IP_FW_NETGRAPH: 295 if (ng_ipfw_input_p == NULL) { 296 ret = PFIL_DROPPED; 297 break; 298 } 299 MPASS(args.flags & IPFW_ARGS_REF); 300 (void )ng_ipfw_input_p(m0, dir, &args, 301 (ipfw == IP_FW_NGTEE) ? 1 : 0); 302 if (ipfw == IP_FW_NGTEE) /* ignore errors for NGTEE */ 303 goto again; /* continue with packet */ 304 ret = PFIL_CONSUMED; 305 break; 306 307 case IP_FW_NAT: 308 /* honor one-pass in case of successful nat */ 309 if (V_fw_one_pass) 310 break; 311 goto again; 312 313 case IP_FW_REASS: 314 goto again; /* continue with packet */ 315 316 default: 317 KASSERT(0, ("%s: unknown retval", __func__)); 318 } 319 320 if (ret != PFIL_PASS) { 321 if (*m0) 322 FREE_PKT(*m0); 323 *m0 = NULL; 324 } 325 326 return (ret); 327 } 328 329 /* 330 * ipfw processing for ethernet packets (in and out). 331 */ 332 static pfil_return_t 333 ipfw_check_frame(struct mbuf **m0, struct ifnet *ifp, int dir, 334 void *ruleset __unused, struct inpcb *inp) 335 { 336 struct ip_fw_args args; 337 struct ether_header save_eh; 338 struct ether_header *eh; 339 struct m_tag *mtag; 340 struct mbuf *m; 341 pfil_return_t ret; 342 int i; 343 344 args.flags = IPFW_ARGS_ETHER; 345 again: 346 /* fetch start point from rule, if any. remove the tag if present. */ 347 mtag = m_tag_locate(*m0, MTAG_IPFW_RULE, 0, NULL); 348 if (mtag != NULL) { 349 args.rule = *((struct ipfw_rule_ref *)(mtag+1)); 350 m_tag_delete(*m0, mtag); 351 if (args.rule.info & IPFW_ONEPASS) 352 return (0); 353 args.flags |= IPFW_ARGS_REF; 354 } 355 356 /* I need some amt of data to be contiguous */ 357 m = *m0; 358 i = min(m->m_pkthdr.len, max_protohdr); 359 if (m->m_len < i) { 360 m = m_pullup(m, i); 361 if (m == NULL) { 362 *m0 = m; 363 return (0); 364 } 365 } 366 eh = mtod(m, struct ether_header *); 367 save_eh = *eh; /* save copy for restore below */ 368 m_adj(m, ETHER_HDR_LEN); /* strip ethernet header */ 369 370 args.m = m; /* the packet we are looking at */ 371 args.oif = dir & PFIL_OUT ? ifp: NULL; /* destination, if any */ 372 args.eh = &save_eh; /* MAC header for bridged/MAC packets */ 373 args.inp = inp; /* used by ipfw uid/gid/jail rules */ 374 i = ipfw_chk(&args); 375 m = args.m; 376 if (m != NULL) { 377 /* 378 * Restore Ethernet header, as needed, in case the 379 * mbuf chain was replaced by ipfw. 380 */ 381 M_PREPEND(m, ETHER_HDR_LEN, M_NOWAIT); 382 if (m == NULL) { 383 *m0 = NULL; 384 return (0); 385 } 386 if (eh != mtod(m, struct ether_header *)) 387 bcopy(&save_eh, mtod(m, struct ether_header *), 388 ETHER_HDR_LEN); 389 } 390 *m0 = m; 391 392 ret = PFIL_PASS; 393 /* Check result of ipfw_chk() */ 394 switch (i) { 395 case IP_FW_PASS: 396 break; 397 398 case IP_FW_DENY: 399 ret = PFIL_DROPPED; 400 break; 401 402 case IP_FW_DUMMYNET: 403 if (ip_dn_io_ptr == NULL) { 404 ret = PFIL_DROPPED; 405 break; 406 } 407 *m0 = NULL; 408 dir = (dir & PFIL_IN) ? DIR_IN : DIR_OUT; 409 MPASS(args.flags & IPFW_ARGS_REF); 410 ip_dn_io_ptr(&m, dir | PROTO_LAYER2, &args); 411 return (PFIL_CONSUMED); 412 413 case IP_FW_NGTEE: 414 case IP_FW_NETGRAPH: 415 if (ng_ipfw_input_p == NULL) { 416 ret = PFIL_DROPPED; 417 break; 418 } 419 MPASS(args.flags & IPFW_ARGS_REF); 420 (void )ng_ipfw_input_p(m0, (dir & PFIL_IN) ? DIR_IN : DIR_OUT, 421 &args, (i == IP_FW_NGTEE) ? 1 : 0); 422 if (i == IP_FW_NGTEE) /* ignore errors for NGTEE */ 423 goto again; /* continue with packet */ 424 ret = PFIL_CONSUMED; 425 break; 426 427 default: 428 KASSERT(0, ("%s: unknown retval", __func__)); 429 } 430 431 if (ret != PFIL_PASS) { 432 if (*m0) 433 FREE_PKT(*m0); 434 *m0 = NULL; 435 } 436 437 return (ret); 438 } 439 440 /* do the divert, return 1 on error 0 on success */ 441 static int 442 ipfw_divert(struct mbuf **m0, int incoming, struct ipfw_rule_ref *rule, 443 int tee) 444 { 445 /* 446 * ipfw_chk() has already tagged the packet with the divert tag. 447 * If tee is set, copy packet and return original. 448 * If not tee, consume packet and send it to divert socket. 449 */ 450 struct mbuf *clone; 451 struct ip *ip = mtod(*m0, struct ip *); 452 struct m_tag *tag; 453 454 /* Cloning needed for tee? */ 455 if (tee == 0) { 456 clone = *m0; /* use the original mbuf */ 457 *m0 = NULL; 458 } else { 459 clone = m_dup(*m0, M_NOWAIT); 460 /* If we cannot duplicate the mbuf, we sacrifice the divert 461 * chain and continue with the tee-ed packet. 462 */ 463 if (clone == NULL) 464 return 1; 465 } 466 467 /* 468 * Divert listeners can normally handle non-fragmented packets, 469 * but we can only reass in the non-tee case. 470 * This means that listeners on a tee rule may get fragments, 471 * and have to live with that. 472 * Note that we now have the 'reass' ipfw option so if we care 473 * we can do it before a 'tee'. 474 */ 475 if (!tee) switch (ip->ip_v) { 476 case IPVERSION: 477 if (ntohs(ip->ip_off) & (IP_MF | IP_OFFMASK)) { 478 int hlen; 479 struct mbuf *reass; 480 481 reass = ip_reass(clone); /* Reassemble packet. */ 482 if (reass == NULL) 483 return 0; /* not an error */ 484 /* if reass = NULL then it was consumed by ip_reass */ 485 /* 486 * IP header checksum fixup after reassembly and leave header 487 * in network byte order. 488 */ 489 ip = mtod(reass, struct ip *); 490 hlen = ip->ip_hl << 2; 491 ip->ip_sum = 0; 492 if (hlen == sizeof(struct ip)) 493 ip->ip_sum = in_cksum_hdr(ip); 494 else 495 ip->ip_sum = in_cksum(reass, hlen); 496 clone = reass; 497 } 498 break; 499 #ifdef INET6 500 case IPV6_VERSION >> 4: 501 { 502 struct ip6_hdr *const ip6 = mtod(clone, struct ip6_hdr *); 503 504 if (ip6->ip6_nxt == IPPROTO_FRAGMENT) { 505 int nxt, off; 506 507 off = sizeof(struct ip6_hdr); 508 nxt = frag6_input(&clone, &off, 0); 509 if (nxt == IPPROTO_DONE) 510 return (0); 511 } 512 break; 513 } 514 #endif 515 } 516 517 /* attach a tag to the packet with the reinject info */ 518 tag = m_tag_alloc(MTAG_IPFW_RULE, 0, 519 sizeof(struct ipfw_rule_ref), M_NOWAIT); 520 if (tag == NULL) { 521 FREE_PKT(clone); 522 return 1; 523 } 524 *((struct ipfw_rule_ref *)(tag+1)) = *rule; 525 m_tag_prepend(clone, tag); 526 527 /* Do the dirty job... */ 528 ip_divert_ptr(clone, incoming); 529 return 0; 530 } 531 532 /* 533 * attach or detach hooks for a given protocol family 534 */ 535 VNET_DEFINE_STATIC(pfil_hook_t, ipfw_inet_hook); 536 #define V_ipfw_inet_hook VNET(ipfw_inet_hook) 537 #ifdef INET6 538 VNET_DEFINE_STATIC(pfil_hook_t, ipfw_inet6_hook); 539 #define V_ipfw_inet6_hook VNET(ipfw_inet6_hook) 540 #endif 541 VNET_DEFINE_STATIC(pfil_hook_t, ipfw_link_hook); 542 #define V_ipfw_link_hook VNET(ipfw_link_hook) 543 544 static int 545 ipfw_hook(int onoff, int pf) 546 { 547 struct pfil_hook_args pha; 548 struct pfil_link_args pla; 549 pfil_hook_t *h; 550 551 pha.pa_version = PFIL_VERSION; 552 pha.pa_flags = PFIL_IN | PFIL_OUT; 553 pha.pa_modname = "ipfw"; 554 pha.pa_ruleset = NULL; 555 556 pla.pa_version = PFIL_VERSION; 557 pla.pa_flags = PFIL_IN | PFIL_OUT | 558 PFIL_HEADPTR | PFIL_HOOKPTR; 559 560 switch (pf) { 561 case AF_INET: 562 pha.pa_func = ipfw_check_packet; 563 pha.pa_type = PFIL_TYPE_IP4; 564 pha.pa_rulname = "default"; 565 h = &V_ipfw_inet_hook; 566 pla.pa_head = V_inet_pfil_head; 567 break; 568 #ifdef INET6 569 case AF_INET6: 570 pha.pa_func = ipfw_check_packet; 571 pha.pa_type = PFIL_TYPE_IP6; 572 pha.pa_rulname = "default6"; 573 h = &V_ipfw_inet6_hook; 574 pla.pa_head = V_inet6_pfil_head; 575 break; 576 #endif 577 case AF_LINK: 578 pha.pa_func = ipfw_check_frame; 579 pha.pa_type = PFIL_TYPE_ETHERNET; 580 pha.pa_rulname = "default-link"; 581 h = &V_ipfw_link_hook; 582 pla.pa_head = V_link_pfil_head; 583 break; 584 } 585 586 if (onoff) { 587 *h = pfil_add_hook(&pha); 588 pla.pa_hook = *h; 589 (void)pfil_link(&pla); 590 } else 591 if (*h != NULL) 592 pfil_remove_hook(*h); 593 594 return 0; 595 } 596 597 int 598 ipfw_attach_hooks(int arg) 599 { 600 int error = 0; 601 602 if (arg == 0) /* detach */ 603 ipfw_hook(0, AF_INET); 604 else if (V_fw_enable && ipfw_hook(1, AF_INET) != 0) { 605 error = ENOENT; /* see ip_fw_pfil.c::ipfw_hook() */ 606 printf("ipfw_hook() error\n"); 607 } 608 #ifdef INET6 609 if (arg == 0) /* detach */ 610 ipfw_hook(0, AF_INET6); 611 else if (V_fw6_enable && ipfw_hook(1, AF_INET6) != 0) { 612 error = ENOENT; 613 printf("ipfw6_hook() error\n"); 614 } 615 #endif 616 if (arg == 0) /* detach */ 617 ipfw_hook(0, AF_LINK); 618 else if (V_fwlink_enable && ipfw_hook(1, AF_LINK) != 0) { 619 error = ENOENT; 620 printf("ipfw_link_hook() error\n"); 621 } 622 return error; 623 } 624 625 int 626 ipfw_chg_hook(SYSCTL_HANDLER_ARGS) 627 { 628 int newval; 629 int error; 630 int af; 631 632 if (arg1 == &V_fw_enable) 633 af = AF_INET; 634 #ifdef INET6 635 else if (arg1 == &V_fw6_enable) 636 af = AF_INET6; 637 #endif 638 else if (arg1 == &V_fwlink_enable) 639 af = AF_LINK; 640 else 641 return (EINVAL); 642 643 newval = *(int *)arg1; 644 /* Handle sysctl change */ 645 error = sysctl_handle_int(oidp, &newval, 0, req); 646 647 if (error) 648 return (error); 649 650 /* Formalize new value */ 651 newval = (newval) ? 1 : 0; 652 653 if (*(int *)arg1 == newval) 654 return (0); 655 656 error = ipfw_hook(newval, af); 657 if (error) 658 return (error); 659 *(int *)arg1 = newval; 660 661 return (0); 662 } 663 /* end of file */ 664