2 3/* 4 * Copyright (C) 2012 by Darren Reed. 5 * 6 * See the IPFILTER.LICENCE file for details on licencing. 7 */ 8#if !defined(lint) 9static const char sccsid[] = "@(#)ip_fil.c 2.41 6/5/96 (C) 1993-2000 Darren Reed"; 10static const char rcsid[] = "@(#)$Id$"; 11#endif 12 13#if defined(KERNEL) || defined(_KERNEL) 14# undef KERNEL 15# undef _KERNEL 16# define KERNEL 1 17# define _KERNEL 1 18#endif 19#if defined(__FreeBSD_version) && (__FreeBSD_version >= 400000) && \ 20 !defined(KLD_MODULE) && !defined(IPFILTER_LKM) 21# include "opt_inet6.h" 22#endif 23#if defined(__FreeBSD_version) && (__FreeBSD_version >= 440000) && \ 24 !defined(KLD_MODULE) && !defined(IPFILTER_LKM) 25# include "opt_random_ip_id.h" 26#endif 27#include <sys/param.h> 28#include <sys/errno.h> 29#include <sys/types.h> 30#include <sys/file.h> 31# include <sys/fcntl.h> 32# include <sys/filio.h> 33#include <sys/time.h> 34#include <sys/systm.h> 35# include <sys/dirent.h> 36# include <sys/mbuf.h> 37# include <sys/sockopt.h> 38#if !defined(__hpux) 39# include <sys/mbuf.h> 40#endif 41#include <sys/socket.h> 42# include <sys/selinfo.h> 43# include <netinet/tcp_var.h> 44 45#include <net/if.h> 46# include <net/if_var.h> 47# include <net/netisr.h> 48#include <net/route.h> 49#include <netinet/in.h> 50#include <netinet/in_var.h> 51#include <netinet/in_systm.h> 52#include <netinet/ip.h> 53#include <netinet/ip_var.h> 54#include <netinet/tcp.h> 55#if defined(__osf__) 56# include <netinet/tcp_timer.h> 57#endif 58#include <netinet/udp.h> 59#include <netinet/tcpip.h> 60#include <netinet/ip_icmp.h> 61#include "netinet/ip_compat.h" 62#ifdef USE_INET6 63# include <netinet/icmp6.h> 64#endif 65#include "netinet/ip_fil.h" 66#include "netinet/ip_nat.h" 67#include "netinet/ip_frag.h" 68#include "netinet/ip_state.h" 69#include "netinet/ip_proxy.h" 70#include "netinet/ip_auth.h" 71#include "netinet/ip_sync.h" 72#include "netinet/ip_lookup.h" 73#include "netinet/ip_dstlist.h" 74#ifdef IPFILTER_SCAN 75#include "netinet/ip_scan.h" 76#endif 77#include "netinet/ip_pool.h" 78# include <sys/malloc.h> 79#include <sys/kernel.h> 80#ifdef CSUM_DATA_VALID 81#include <machine/in_cksum.h> 82#endif 83extern int ip_optcopy __P((struct ip *, struct ip *)); 84 85 86# ifdef IPFILTER_M_IPFILTER 87MALLOC_DEFINE(M_IPFILTER, "ipfilter", "IP Filter packet filter data structures"); 88# endif 89 90 91static u_short ipid = 0; 92static int (*ipf_savep) __P((void *, ip_t *, int, void *, int, struct mbuf **)); 93static int ipf_send_ip __P((fr_info_t *, mb_t *)); 94static void ipf_timer_func __P((void *arg)); 95int ipf_locks_done = 0; 96 97ipf_main_softc_t ipfmain; 98 99# include <sys/conf.h> 100# if defined(NETBSD_PF) 101# include <net/pfil.h> 102# endif /* NETBSD_PF */ 103/* 104 * We provide the ipf_checkp name just to minimize changes later. 105 */ 106int (*ipf_checkp) __P((void *, ip_t *ip, int hlen, void *ifp, int out, mb_t **mp)); 107 108 109static eventhandler_tag ipf_arrivetag, ipf_departtag, ipf_clonetag; 110 111static void ipf_ifevent(void *arg); 112 113static void ipf_ifevent(arg) 114 void *arg; 115{ 116 ipf_sync(arg, NULL); 117} 118 119 120 121static int 122ipf_check_wrapper(void *arg, struct mbuf **mp, struct ifnet *ifp, int dir) 123{ 124 struct ip *ip = mtod(*mp, struct ip *); 125 int rv; 126 127 /* 128 * IPFilter expects evreything in network byte order 129 */ 130#if (__FreeBSD_version < 1000019) 131 ip->ip_len = htons(ip->ip_len); 132 ip->ip_off = htons(ip->ip_off); 133#endif 134 rv = ipf_check(&ipfmain, ip, ip->ip_hl << 2, ifp, (dir == PFIL_OUT), 135 mp); 136#if (__FreeBSD_version < 1000019) 137 if ((rv == 0) && (*mp != NULL)) { 138 ip = mtod(*mp, struct ip *); 139 ip->ip_len = ntohs(ip->ip_len); 140 ip->ip_off = ntohs(ip->ip_off); 141 } 142#endif 143 return rv; 144} 145 146# ifdef USE_INET6 147# include <netinet/ip6.h> 148 149static int 150ipf_check_wrapper6(void *arg, struct mbuf **mp, struct ifnet *ifp, int dir) 151{ 152 return (ipf_check(&ipfmain, mtod(*mp, struct ip *), 153 sizeof(struct ip6_hdr), ifp, (dir == PFIL_OUT), mp)); 154} 155# endif 156#if defined(IPFILTER_LKM) 157int ipf_identify(s) 158 char *s; 159{ 160 if (strcmp(s, "ipl") == 0) 161 return 1; 162 return 0; 163} 164#endif /* IPFILTER_LKM */ 165 166 167static void 168ipf_timer_func(arg) 169 void *arg; 170{ 171 ipf_main_softc_t *softc = arg; 172 SPL_INT(s); 173 174 SPL_NET(s); 175 READ_ENTER(&softc->ipf_global); 176 177 if (softc->ipf_running > 0) 178 ipf_slowtimer(softc); 179 180 if (softc->ipf_running == -1 || softc->ipf_running == 1) { 181#if 0 182 softc->ipf_slow_ch = timeout(ipf_timer_func, softc, hz/2); 183#endif 184 callout_init(&softc->ipf_slow_ch, CALLOUT_MPSAFE); 185 callout_reset(&softc->ipf_slow_ch, 186 (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT, 187 ipf_timer_func, softc); 188 } 189 RWLOCK_EXIT(&softc->ipf_global); 190 SPL_X(s); 191} 192 193 194int 195ipfattach(softc) 196 ipf_main_softc_t *softc; 197{ 198#ifdef USE_SPL 199 int s; 200#endif 201 202 SPL_NET(s); 203 if (softc->ipf_running > 0) { 204 SPL_X(s); 205 return EBUSY; 206 } 207 208 if (ipf_init_all(softc) < 0) { 209 SPL_X(s); 210 return EIO; 211 } 212 213 214 if (ipf_checkp != ipf_check) { 215 ipf_savep = ipf_checkp; 216 ipf_checkp = ipf_check; 217 } 218 219 bzero((char *)ipfmain.ipf_selwait, sizeof(ipfmain.ipf_selwait)); 220 softc->ipf_running = 1; 221 222 if (softc->ipf_control_forwarding & 1) 223 V_ipforwarding = 1; 224 225 ipid = 0; 226 227 SPL_X(s); 228#if 0 229 softc->ipf_slow_ch = timeout(ipf_timer_func, softc, 230 (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT); 231#endif 232 callout_init(&softc->ipf_slow_ch, CALLOUT_MPSAFE); 233 callout_reset(&softc->ipf_slow_ch, (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT, 234 ipf_timer_func, softc); 235 return 0; 236} 237 238 239/* 240 * Disable the filter by removing the hooks from the IP input/output 241 * stream. 242 */ 243int 244ipfdetach(softc) 245 ipf_main_softc_t *softc; 246{ 247#ifdef USE_SPL 248 int s; 249#endif 250 251 if (softc->ipf_control_forwarding & 2) 252 V_ipforwarding = 0; 253 254 SPL_NET(s); 255 256#if 0 257 if (softc->ipf_slow_ch.callout != NULL) 258 untimeout(ipf_timer_func, softc, softc->ipf_slow_ch); 259 bzero(&softc->ipf_slow, sizeof(softc->ipf_slow)); 260#endif 261 callout_drain(&softc->ipf_slow_ch); 262 263#ifndef NETBSD_PF 264 if (ipf_checkp != NULL) 265 ipf_checkp = ipf_savep; 266 ipf_savep = NULL; 267#endif 268 269 ipf_fini_all(softc); 270 271 softc->ipf_running = -2; 272 273 SPL_X(s); 274 275 return 0; 276} 277 278 279/* 280 * Filter ioctl interface. 281 */ 282int 283ipfioctl(dev, cmd, data, mode 284, p) 285 struct thread *p; 286# define p_cred td_ucred 287# define p_uid td_ucred->cr_ruid 288 struct cdev *dev; 289 ioctlcmd_t cmd; 290 caddr_t data; 291 int mode; 292{ 293 int error = 0, unit = 0; 294 SPL_INT(s); 295 296#if (BSD >= 199306) 297 if (securelevel_ge(p->p_cred, 3) && (mode & FWRITE)) 298 { 299 ipfmain.ipf_interror = 130001; 300 return EPERM; 301 } 302#endif 303 304 unit = GET_MINOR(dev); 305 if ((IPL_LOGMAX < unit) || (unit < 0)) { 306 ipfmain.ipf_interror = 130002; 307 return ENXIO; 308 } 309 310 if (ipfmain.ipf_running <= 0) { 311 if (unit != IPL_LOGIPF && cmd != SIOCIPFINTERROR) { 312 ipfmain.ipf_interror = 130003; 313 return EIO; 314 } 315 if (cmd != SIOCIPFGETNEXT && cmd != SIOCIPFGET && 316 cmd != SIOCIPFSET && cmd != SIOCFRENB && 317 cmd != SIOCGETFS && cmd != SIOCGETFF && 318 cmd != SIOCIPFINTERROR) { 319 ipfmain.ipf_interror = 130004; 320 return EIO; 321 } 322 } 323 324 SPL_NET(s); 325 326 error = ipf_ioctlswitch(&ipfmain, unit, data, cmd, mode, p->p_uid, p); 327 if (error != -1) { 328 SPL_X(s); 329 return error; 330 } 331 332 SPL_X(s); 333 334 return error; 335} 336 337 338/* 339 * ipf_send_reset - this could conceivably be a call to tcp_respond(), but that 340 * requires a large amount of setting up and isn't any more efficient. 341 */ 342int 343ipf_send_reset(fin) 344 fr_info_t *fin; 345{ 346 struct tcphdr *tcp, *tcp2; 347 int tlen = 0, hlen; 348 struct mbuf *m; 349#ifdef USE_INET6 350 ip6_t *ip6; 351#endif 352 ip_t *ip; 353 354 tcp = fin->fin_dp; 355 if (tcp->th_flags & TH_RST) 356 return -1; /* feedback loop */ 357 358 if (ipf_checkl4sum(fin) == -1) 359 return -1; 360 361 tlen = fin->fin_dlen - (TCP_OFF(tcp) << 2) + 362 ((tcp->th_flags & TH_SYN) ? 1 : 0) + 363 ((tcp->th_flags & TH_FIN) ? 1 : 0); 364 365#ifdef USE_INET6 366 hlen = (fin->fin_v == 6) ? sizeof(ip6_t) : sizeof(ip_t); 367#else 368 hlen = sizeof(ip_t); 369#endif 370#ifdef MGETHDR 371 MGETHDR(m, M_NOWAIT, MT_HEADER); 372#else 373 MGET(m, M_NOWAIT, MT_HEADER); 374#endif 375 if (m == NULL) 376 return -1; 377 if (sizeof(*tcp2) + hlen > MLEN) { 378 MCLGET(m, M_NOWAIT); 379 if ((m->m_flags & M_EXT) == 0) { 380 FREE_MB_T(m); 381 return -1; 382 } 383 } 384 385 m->m_len = sizeof(*tcp2) + hlen; 386#if (BSD >= 199103) 387 m->m_data += max_linkhdr; 388 m->m_pkthdr.len = m->m_len; 389 m->m_pkthdr.rcvif = (struct ifnet *)0; 390#endif 391 ip = mtod(m, struct ip *); 392 bzero((char *)ip, hlen); 393#ifdef USE_INET6 394 ip6 = (ip6_t *)ip; 395#endif 396 tcp2 = (struct tcphdr *)((char *)ip + hlen); 397 tcp2->th_sport = tcp->th_dport; 398 tcp2->th_dport = tcp->th_sport; 399 400 if (tcp->th_flags & TH_ACK) { 401 tcp2->th_seq = tcp->th_ack; 402 tcp2->th_flags = TH_RST; 403 tcp2->th_ack = 0; 404 } else { 405 tcp2->th_seq = 0; 406 tcp2->th_ack = ntohl(tcp->th_seq); 407 tcp2->th_ack += tlen; 408 tcp2->th_ack = htonl(tcp2->th_ack); 409 tcp2->th_flags = TH_RST|TH_ACK; 410 } 411 TCP_X2_A(tcp2, 0); 412 TCP_OFF_A(tcp2, sizeof(*tcp2) >> 2); 413 tcp2->th_win = tcp->th_win; 414 tcp2->th_sum = 0; 415 tcp2->th_urp = 0; 416 417#ifdef USE_INET6 418 if (fin->fin_v == 6) { 419 ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow; 420 ip6->ip6_plen = htons(sizeof(struct tcphdr)); 421 ip6->ip6_nxt = IPPROTO_TCP; 422 ip6->ip6_hlim = 0; 423 ip6->ip6_src = fin->fin_dst6.in6; 424 ip6->ip6_dst = fin->fin_src6.in6; 425 tcp2->th_sum = in6_cksum(m, IPPROTO_TCP, 426 sizeof(*ip6), sizeof(*tcp2)); 427 return ipf_send_ip(fin, m); 428 } 429#endif 430 ip->ip_p = IPPROTO_TCP; 431 ip->ip_len = htons(sizeof(struct tcphdr)); 432 ip->ip_src.s_addr = fin->fin_daddr; 433 ip->ip_dst.s_addr = fin->fin_saddr; 434 tcp2->th_sum = in_cksum(m, hlen + sizeof(*tcp2)); 435 ip->ip_len = htons(hlen + sizeof(*tcp2)); 436 return ipf_send_ip(fin, m); 437} 438 439 440/* 441 * ip_len must be in network byte order when called. 442 */ 443static int 444ipf_send_ip(fin, m) 445 fr_info_t *fin; 446 mb_t *m; 447{ 448 fr_info_t fnew; 449 ip_t *ip, *oip; 450 int hlen; 451 452 ip = mtod(m, ip_t *); 453 bzero((char *)&fnew, sizeof(fnew)); 454 fnew.fin_main_soft = fin->fin_main_soft; 455 456 IP_V_A(ip, fin->fin_v); 457 switch (fin->fin_v) 458 { 459 case 4 : 460 oip = fin->fin_ip; 461 hlen = sizeof(*oip); 462 fnew.fin_v = 4; 463 fnew.fin_p = ip->ip_p; 464 fnew.fin_plen = ntohs(ip->ip_len); 465 IP_HL_A(ip, sizeof(*oip) >> 2); 466 ip->ip_tos = oip->ip_tos; 467 ip->ip_id = fin->fin_ip->ip_id; 468#if defined(FreeBSD) && (__FreeBSD_version > 460000) 469 ip->ip_off = htons(path_mtu_discovery ? IP_DF : 0); 470#else 471 ip->ip_off = 0; 472#endif 473 ip->ip_ttl = V_ip_defttl; 474 ip->ip_sum = 0; 475 break; 476#ifdef USE_INET6 477 case 6 : 478 { 479 ip6_t *ip6 = (ip6_t *)ip; 480 481 ip6->ip6_vfc = 0x60; 482 ip6->ip6_hlim = IPDEFTTL; 483 484 hlen = sizeof(*ip6); 485 fnew.fin_p = ip6->ip6_nxt; 486 fnew.fin_v = 6; 487 fnew.fin_plen = ntohs(ip6->ip6_plen) + hlen; 488 break; 489 } 490#endif 491 default : 492 return EINVAL; 493 } 494#ifdef IPSEC 495 m->m_pkthdr.rcvif = NULL; 496#endif 497 498 fnew.fin_ifp = fin->fin_ifp; 499 fnew.fin_flx = FI_NOCKSUM; 500 fnew.fin_m = m; 501 fnew.fin_ip = ip; 502 fnew.fin_mp = &m; 503 fnew.fin_hlen = hlen; 504 fnew.fin_dp = (char *)ip + hlen; 505 (void) ipf_makefrip(hlen, ip, &fnew); 506 507 return ipf_fastroute(m, &m, &fnew, NULL); 508} 509 510 511int 512ipf_send_icmp_err(type, fin, dst) 513 int type; 514 fr_info_t *fin; 515 int dst; 516{ 517 int err, hlen, xtra, iclen, ohlen, avail, code; 518 struct in_addr dst4; 519 struct icmp *icmp; 520 struct mbuf *m; 521 i6addr_t dst6; 522 void *ifp; 523#ifdef USE_INET6 524 ip6_t *ip6; 525#endif 526 ip_t *ip, *ip2; 527 528 if ((type < 0) || (type >= ICMP_MAXTYPE)) 529 return -1; 530 531 code = fin->fin_icode; 532#ifdef USE_INET6 533#if 0 534 /* XXX Fix an off by one error: s/>/>=/ 535 was: 536 if ((code < 0) || (code > sizeof(icmptoicmp6unreach)/sizeof(int))) 537 Fix obtained from NetBSD ip_fil_netbsd.c r1.4: */ 538#endif 539 if ((code < 0) || (code >= sizeof(icmptoicmp6unreach)/sizeof(int))) 540 return -1; 541#endif 542 543 if (ipf_checkl4sum(fin) == -1) 544 return -1; 545#ifdef MGETHDR 546 MGETHDR(m, M_NOWAIT, MT_HEADER); 547#else 548 MGET(m, M_NOWAIT, MT_HEADER); 549#endif 550 if (m == NULL) 551 return -1; 552 avail = MHLEN; 553 554 xtra = 0; 555 hlen = 0; 556 ohlen = 0; 557 dst4.s_addr = 0; 558 ifp = fin->fin_ifp; 559 if (fin->fin_v == 4) { 560 if ((fin->fin_p == IPPROTO_ICMP) && !(fin->fin_flx & FI_SHORT)) 561 switch (ntohs(fin->fin_data[0]) >> 8) 562 { 563 case ICMP_ECHO : 564 case ICMP_TSTAMP : 565 case ICMP_IREQ : 566 case ICMP_MASKREQ : 567 break; 568 default : 569 FREE_MB_T(m); 570 return 0; 571 } 572 573 if (dst == 0) { 574 if (ipf_ifpaddr(&ipfmain, 4, FRI_NORMAL, ifp, 575 &dst6, NULL) == -1) { 576 FREE_MB_T(m); 577 return -1; 578 } 579 dst4 = dst6.in4; 580 } else 581 dst4.s_addr = fin->fin_daddr; 582 583 hlen = sizeof(ip_t); 584 ohlen = fin->fin_hlen; 585 iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen; 586 if (fin->fin_hlen < fin->fin_plen) 587 xtra = MIN(fin->fin_dlen, 8); 588 else 589 xtra = 0; 590 } 591 592#ifdef USE_INET6 593 else if (fin->fin_v == 6) { 594 hlen = sizeof(ip6_t); 595 ohlen = sizeof(ip6_t); 596 iclen = hlen + offsetof(struct icmp, icmp_ip) + ohlen; 597 type = icmptoicmp6types[type]; 598 if (type == ICMP6_DST_UNREACH) 599 code = icmptoicmp6unreach[code]; 600 601 if (iclen + max_linkhdr + fin->fin_plen > avail) { 602 MCLGET(m, M_NOWAIT); 603 if ((m->m_flags & M_EXT) == 0) { 604 FREE_MB_T(m); 605 return -1; 606 } 607 avail = MCLBYTES; 608 } 609 xtra = MIN(fin->fin_plen, avail - iclen - max_linkhdr); 610 xtra = MIN(xtra, IPV6_MMTU - iclen); 611 if (dst == 0) { 612 if (ipf_ifpaddr(&ipfmain, 6, FRI_NORMAL, ifp, 613 &dst6, NULL) == -1) { 614 FREE_MB_T(m); 615 return -1; 616 } 617 } else 618 dst6 = fin->fin_dst6; 619 } 620#endif 621 else { 622 FREE_MB_T(m); 623 return -1; 624 } 625 626 avail -= (max_linkhdr + iclen); 627 if (avail < 0) { 628 FREE_MB_T(m); 629 return -1; 630 } 631 if (xtra > avail) 632 xtra = avail; 633 iclen += xtra; 634 m->m_data += max_linkhdr; 635 m->m_pkthdr.rcvif = (struct ifnet *)0; 636 m->m_pkthdr.len = iclen; 637 m->m_len = iclen; 638 ip = mtod(m, ip_t *); 639 icmp = (struct icmp *)((char *)ip + hlen); 640 ip2 = (ip_t *)&icmp->icmp_ip; 641 642 icmp->icmp_type = type; 643 icmp->icmp_code = fin->fin_icode; 644 icmp->icmp_cksum = 0; 645#ifdef icmp_nextmtu 646 if (type == ICMP_UNREACH && fin->fin_icode == ICMP_UNREACH_NEEDFRAG) { 647 if (fin->fin_mtu != 0) { 648 icmp->icmp_nextmtu = htons(fin->fin_mtu); 649 650 } else if (ifp != NULL) { 651 icmp->icmp_nextmtu = htons(GETIFMTU_4(ifp)); 652 653 } else { /* make up a number... */ 654 icmp->icmp_nextmtu = htons(fin->fin_plen - 20); 655 } 656 } 657#endif 658 659 bcopy((char *)fin->fin_ip, (char *)ip2, ohlen); 660 661#ifdef USE_INET6 662 ip6 = (ip6_t *)ip; 663 if (fin->fin_v == 6) { 664 ip6->ip6_flow = ((ip6_t *)fin->fin_ip)->ip6_flow; 665 ip6->ip6_plen = htons(iclen - hlen); 666 ip6->ip6_nxt = IPPROTO_ICMPV6; 667 ip6->ip6_hlim = 0; 668 ip6->ip6_src = dst6.in6; 669 ip6->ip6_dst = fin->fin_src6.in6; 670 if (xtra > 0) 671 bcopy((char *)fin->fin_ip + ohlen, 672 (char *)&icmp->icmp_ip + ohlen, xtra); 673 icmp->icmp_cksum = in6_cksum(m, IPPROTO_ICMPV6, 674 sizeof(*ip6), iclen - hlen); 675 } else 676#endif 677 { 678 ip->ip_p = IPPROTO_ICMP; 679 ip->ip_src.s_addr = dst4.s_addr; 680 ip->ip_dst.s_addr = fin->fin_saddr; 681 682 if (xtra > 0) 683 bcopy((char *)fin->fin_ip + ohlen, 684 (char *)&icmp->icmp_ip + ohlen, xtra); 685 icmp->icmp_cksum = ipf_cksum((u_short *)icmp, 686 sizeof(*icmp) + 8); 687 ip->ip_len = htons(iclen); 688 ip->ip_p = IPPROTO_ICMP; 689 } 690 err = ipf_send_ip(fin, m); 691 return err; 692} 693 694 695 696 697/* 698 * m0 - pointer to mbuf where the IP packet starts 699 * mpp - pointer to the mbuf pointer that is the start of the mbuf chain 700 */ 701int 702ipf_fastroute(m0, mpp, fin, fdp) 703 mb_t *m0, **mpp; 704 fr_info_t *fin; 705 frdest_t *fdp; 706{ 707 register struct ip *ip, *mhip; 708 register struct mbuf *m = *mpp; 709 register struct route *ro; 710 int len, off, error = 0, hlen, code; 711 struct ifnet *ifp, *sifp; 712 struct sockaddr_in *dst; 713 struct route iproute; 714 u_short ip_off; 715 frdest_t node; 716 frentry_t *fr; 717 718 ro = NULL; 719 720#ifdef M_WRITABLE 721 /* 722 * HOT FIX/KLUDGE: 723 * 724 * If the mbuf we're about to send is not writable (because of 725 * a cluster reference, for example) we'll need to make a copy 726 * of it since this routine modifies the contents. 727 * 728 * If you have non-crappy network hardware that can transmit data 729 * from the mbuf, rather than making a copy, this is gonna be a 730 * problem. 731 */ 732 if (M_WRITABLE(m) == 0) { 733 m0 = m_dup(m, M_NOWAIT); 734 if (m0 != 0) { 735 FREE_MB_T(m); 736 m = m0; 737 *mpp = m; 738 } else { 739 error = ENOBUFS; 740 FREE_MB_T(m); 741 goto done; 742 } 743 } 744#endif 745 746#ifdef USE_INET6 747 if (fin->fin_v == 6) { 748 /* 749 * currently "to <if>" and "to <if>:ip#" are not supported 750 * for IPv6 751 */ 752 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 753 } 754#endif 755 756 hlen = fin->fin_hlen; 757 ip = mtod(m0, struct ip *); 758 ifp = NULL; 759 760 /* 761 * Route packet. 762 */ 763 ro = &iproute; 764 bzero(ro, sizeof (*ro)); 765 dst = (struct sockaddr_in *)&ro->ro_dst; 766 dst->sin_family = AF_INET; 767 dst->sin_addr = ip->ip_dst; 768 769 fr = fin->fin_fr; 770 if ((fr != NULL) && !(fr->fr_flags & FR_KEEPSTATE) && (fdp != NULL) && 771 (fdp->fd_type == FRD_DSTLIST)) { 772 if (ipf_dstlist_select_node(fin, fdp->fd_ptr, NULL, &node) == 0) 773 fdp = &node; 774 } 775 776 if (fdp != NULL) 777 ifp = fdp->fd_ptr; 778 else 779 ifp = fin->fin_ifp; 780 781 if ((ifp == NULL) && ((fr == NULL) || !(fr->fr_flags & FR_FASTROUTE))) { 782 error = -2; 783 goto bad; 784 } 785 786 if ((fdp != NULL) && (fdp->fd_ip.s_addr != 0)) 787 dst->sin_addr = fdp->fd_ip; 788 789 dst->sin_len = sizeof(*dst); 790 in_rtalloc(ro, 0); 791 792 if ((ifp == NULL) && (ro->ro_rt != NULL)) 793 ifp = ro->ro_rt->rt_ifp; 794 795 if ((ro->ro_rt == NULL) || (ifp == NULL)) { 796 if (in_localaddr(ip->ip_dst)) 797 error = EHOSTUNREACH; 798 else 799 error = ENETUNREACH; 800 goto bad; 801 } 802 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 803 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 804 if (ro->ro_rt)
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806 807 /* 808 * For input packets which are being "fastrouted", they won't 809 * go back through output filtering and miss their chance to get 810 * NAT'd and counted. Duplicated packets aren't considered to be 811 * part of the normal packet stream, so do not NAT them or pass 812 * them through stateful checking, etc. 813 */ 814 if ((fdp != &fr->fr_dif) && (fin->fin_out == 0)) { 815 sifp = fin->fin_ifp; 816 fin->fin_ifp = ifp; 817 fin->fin_out = 1; 818 (void) ipf_acctpkt(fin, NULL); 819 fin->fin_fr = NULL; 820 if (!fr || !(fr->fr_flags & FR_RETMASK)) { 821 u_32_t pass; 822 823 (void) ipf_state_check(fin, &pass); 824 } 825 826 switch (ipf_nat_checkout(fin, NULL)) 827 { 828 case 0 : 829 break; 830 case 1 : 831 ip->ip_sum = 0; 832 break; 833 case -1 : 834 error = -1; 835 goto bad; 836 break; 837 } 838 839 fin->fin_ifp = sifp; 840 fin->fin_out = 0; 841 } else 842 ip->ip_sum = 0; 843 /* 844 * If small enough for interface, can just send directly. 845 */ 846 if (ntohs(ip->ip_len) <= ifp->if_mtu) { 847 if (!ip->ip_sum) 848 ip->ip_sum = in_cksum(m, hlen); 849 error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst, 850 ro 851 ); 852 goto done; 853 } 854 /* 855 * Too large for interface; fragment if possible. 856 * Must be able to put at least 8 bytes per fragment. 857 */ 858 ip_off = ntohs(ip->ip_off); 859 if (ip_off & IP_DF) { 860 error = EMSGSIZE; 861 goto bad; 862 } 863 len = (ifp->if_mtu - hlen) &~ 7; 864 if (len < 8) { 865 error = EMSGSIZE; 866 goto bad; 867 } 868 869 { 870 int mhlen, firstlen = len; 871 struct mbuf **mnext = &m->m_act; 872 873 /* 874 * Loop through length of segment after first fragment, 875 * make new header and copy data of each part and link onto chain. 876 */ 877 m0 = m; 878 mhlen = sizeof (struct ip); 879 for (off = hlen + len; off < ntohs(ip->ip_len); off += len) { 880#ifdef MGETHDR 881 MGETHDR(m, M_NOWAIT, MT_HEADER); 882#else 883 MGET(m, M_NOWAIT, MT_HEADER); 884#endif 885 if (m == 0) { 886 m = m0; 887 error = ENOBUFS; 888 goto bad; 889 } 890 m->m_data += max_linkhdr; 891 mhip = mtod(m, struct ip *); 892 bcopy((char *)ip, (char *)mhip, sizeof(*ip)); 893 if (hlen > sizeof (struct ip)) { 894 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 895 IP_HL_A(mhip, mhlen >> 2); 896 } 897 m->m_len = mhlen; 898 mhip->ip_off = ((off - hlen) >> 3) + ip_off; 899 if (off + len >= ntohs(ip->ip_len)) 900 len = ntohs(ip->ip_len) - off; 901 else 902 mhip->ip_off |= IP_MF; 903 mhip->ip_len = htons((u_short)(len + mhlen)); 904 *mnext = m; 905 m->m_next = m_copy(m0, off, len); 906 if (m->m_next == 0) { 907 error = ENOBUFS; /* ??? */ 908 goto sendorfree; 909 } 910 m->m_pkthdr.len = mhlen + len; 911 m->m_pkthdr.rcvif = NULL; 912 mhip->ip_off = htons((u_short)mhip->ip_off); 913 mhip->ip_sum = 0; 914 mhip->ip_sum = in_cksum(m, mhlen); 915 mnext = &m->m_act; 916 } 917 /* 918 * Update first fragment by trimming what's been copied out 919 * and updating header, then send each fragment (in order). 920 */ 921 m_adj(m0, hlen + firstlen - ip->ip_len); 922 ip->ip_len = htons((u_short)(hlen + firstlen)); 923 ip->ip_off = htons((u_short)IP_MF); 924 ip->ip_sum = 0; 925 ip->ip_sum = in_cksum(m0, hlen); 926sendorfree: 927 for (m = m0; m; m = m0) { 928 m0 = m->m_act; 929 m->m_act = 0; 930 if (error == 0) 931 error = (*ifp->if_output)(ifp, m, 932 (struct sockaddr *)dst, 933 ro 934 ); 935 else 936 FREE_MB_T(m); 937 } 938 } 939done: 940 if (!error) 941 ipfmain.ipf_frouteok[0]++; 942 else 943 ipfmain.ipf_frouteok[1]++; 944 945 if ((ro != NULL) && (ro->ro_rt != NULL)) { 946 RTFREE(ro->ro_rt); 947 } 948 return 0; 949bad: 950 if (error == EMSGSIZE) { 951 sifp = fin->fin_ifp; 952 code = fin->fin_icode; 953 fin->fin_icode = ICMP_UNREACH_NEEDFRAG; 954 fin->fin_ifp = ifp; 955 (void) ipf_send_icmp_err(ICMP_UNREACH, fin, 1); 956 fin->fin_ifp = sifp; 957 fin->fin_icode = code; 958 } 959 FREE_MB_T(m); 960 goto done; 961} 962 963 964int 965ipf_verifysrc(fin) 966 fr_info_t *fin; 967{ 968 struct sockaddr_in *dst; 969 struct route iproute; 970 971 bzero((char *)&iproute, sizeof(iproute)); 972 dst = (struct sockaddr_in *)&iproute.ro_dst; 973 dst->sin_len = sizeof(*dst); 974 dst->sin_family = AF_INET; 975 dst->sin_addr = fin->fin_src; 976 in_rtalloc(&iproute, 0); 977 if (iproute.ro_rt == NULL) 978 return 0; 979 return (fin->fin_ifp == iproute.ro_rt->rt_ifp); 980} 981 982 983/* 984 * return the first IP Address associated with an interface 985 */ 986int 987ipf_ifpaddr(softc, v, atype, ifptr, inp, inpmask) 988 ipf_main_softc_t *softc; 989 int v, atype; 990 void *ifptr; 991 i6addr_t *inp, *inpmask; 992{ 993#ifdef USE_INET6 994 struct in6_addr *inp6 = NULL; 995#endif 996 struct sockaddr *sock, *mask; 997 struct sockaddr_in *sin; 998 struct ifaddr *ifa; 999 struct ifnet *ifp; 1000 1001 if ((ifptr == NULL) || (ifptr == (void *)-1)) 1002 return -1; 1003 1004 sin = NULL; 1005 ifp = ifptr; 1006 1007 if (v == 4) 1008 inp->in4.s_addr = 0; 1009#ifdef USE_INET6 1010 else if (v == 6) 1011 bzero((char *)inp, sizeof(*inp)); 1012#endif 1013 ifa = TAILQ_FIRST(&ifp->if_addrhead); 1014 1015 sock = ifa->ifa_addr; 1016 while (sock != NULL && ifa != NULL) { 1017 sin = (struct sockaddr_in *)sock; 1018 if ((v == 4) && (sin->sin_family == AF_INET)) 1019 break; 1020#ifdef USE_INET6 1021 if ((v == 6) && (sin->sin_family == AF_INET6)) { 1022 inp6 = &((struct sockaddr_in6 *)sin)->sin6_addr; 1023 if (!IN6_IS_ADDR_LINKLOCAL(inp6) && 1024 !IN6_IS_ADDR_LOOPBACK(inp6)) 1025 break; 1026 } 1027#endif 1028 ifa = TAILQ_NEXT(ifa, ifa_link); 1029 if (ifa != NULL) 1030 sock = ifa->ifa_addr; 1031 } 1032 1033 if (ifa == NULL || sin == NULL) 1034 return -1; 1035 1036 mask = ifa->ifa_netmask; 1037 if (atype == FRI_BROADCAST) 1038 sock = ifa->ifa_broadaddr; 1039 else if (atype == FRI_PEERADDR) 1040 sock = ifa->ifa_dstaddr; 1041 1042 if (sock == NULL) 1043 return -1; 1044 1045#ifdef USE_INET6 1046 if (v == 6) { 1047 return ipf_ifpfillv6addr(atype, (struct sockaddr_in6 *)sock, 1048 (struct sockaddr_in6 *)mask, 1049 inp, inpmask); 1050 } 1051#endif 1052 return ipf_ifpfillv4addr(atype, (struct sockaddr_in *)sock, 1053 (struct sockaddr_in *)mask, 1054 &inp->in4, &inpmask->in4); 1055} 1056 1057 1058u_32_t 1059ipf_newisn(fin) 1060 fr_info_t *fin; 1061{ 1062 u_32_t newiss; 1063 newiss = arc4random(); 1064 return newiss; 1065} 1066 1067 1068/* ------------------------------------------------------------------------ */ 1069/* Function: ipf_nextipid */ 1070/* Returns: int - 0 == success, -1 == error (packet should be droppped) */ 1071/* Parameters: fin(I) - pointer to packet information */ 1072/* */ 1073/* Returns the next IPv4 ID to use for this packet. */ 1074/* ------------------------------------------------------------------------ */ 1075u_short 1076ipf_nextipid(fin) 1077 fr_info_t *fin; 1078{ 1079 u_short id; 1080 1081#ifndef RANDOM_IP_ID 1082 MUTEX_ENTER(&ipfmain.ipf_rw); 1083 id = ipid++; 1084 MUTEX_EXIT(&ipfmain.ipf_rw); 1085#else 1086 id = ip_randomid(); 1087#endif 1088 1089 return id; 1090} 1091 1092 1093INLINE int 1094ipf_checkv4sum(fin) 1095 fr_info_t *fin; 1096{ 1097#ifdef CSUM_DATA_VALID 1098 int manual = 0; 1099 u_short sum; 1100 ip_t *ip; 1101 mb_t *m; 1102 1103 if ((fin->fin_flx & FI_NOCKSUM) != 0) 1104 return 0; 1105 1106 if ((fin->fin_flx & FI_SHORT) != 0) 1107 return 1; 1108 1109 if (fin->fin_cksum != FI_CK_NEEDED) 1110 return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1; 1111 1112 m = fin->fin_m; 1113 if (m == NULL) { 1114 manual = 1; 1115 goto skipauto; 1116 } 1117 ip = fin->fin_ip; 1118 1119 if ((m->m_pkthdr.csum_flags & (CSUM_IP_CHECKED|CSUM_IP_VALID)) == 1120 CSUM_IP_CHECKED) { 1121 fin->fin_cksum = FI_CK_BAD; 1122 fin->fin_flx |= FI_BAD; 1123 return -1; 1124 } 1125 if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) { 1126 if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR) 1127 sum = m->m_pkthdr.csum_data; 1128 else 1129 sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, 1130 htonl(m->m_pkthdr.csum_data + 1131 fin->fin_dlen + fin->fin_p)); 1132 sum ^= 0xffff; 1133 if (sum != 0) { 1134 fin->fin_cksum = FI_CK_BAD; 1135 fin->fin_flx |= FI_BAD; 1136 } else { 1137 fin->fin_cksum = FI_CK_SUMOK; 1138 return 0; 1139 } 1140 } else { 1141 if (m->m_pkthdr.csum_flags == CSUM_DELAY_DATA) { 1142 fin->fin_cksum = FI_CK_L4FULL; 1143 return 0; 1144 } else if (m->m_pkthdr.csum_flags == CSUM_TCP || 1145 m->m_pkthdr.csum_flags == CSUM_UDP) { 1146 fin->fin_cksum = FI_CK_L4PART; 1147 return 0; 1148 } else if (m->m_pkthdr.csum_flags == CSUM_IP) { 1149 fin->fin_cksum = FI_CK_L4PART; 1150 return 0; 1151 } else { 1152 manual = 1; 1153 } 1154 } 1155skipauto: 1156 if (manual != 0) { 1157 if (ipf_checkl4sum(fin) == -1) { 1158 fin->fin_flx |= FI_BAD; 1159 return -1; 1160 } 1161 } 1162#else 1163 if (ipf_checkl4sum(fin) == -1) { 1164 fin->fin_flx |= FI_BAD; 1165 return -1; 1166 } 1167#endif 1168 return 0; 1169} 1170 1171 1172#ifdef USE_INET6 1173INLINE int 1174ipf_checkv6sum(fin) 1175 fr_info_t *fin; 1176{ 1177 if ((fin->fin_flx & FI_NOCKSUM) != 0) 1178 return 0; 1179 1180 if ((fin->fin_flx & FI_SHORT) != 0) 1181 return 1; 1182 1183 if (fin->fin_cksum != FI_CK_NEEDED) 1184 return (fin->fin_cksum > FI_CK_NEEDED) ? 0 : -1; 1185 1186 if (ipf_checkl4sum(fin) == -1) { 1187 fin->fin_flx |= FI_BAD; 1188 return -1; 1189 } 1190 return 0; 1191} 1192#endif /* USE_INET6 */ 1193 1194 1195size_t 1196mbufchainlen(m0) 1197 struct mbuf *m0; 1198 { 1199 size_t len; 1200 1201 if ((m0->m_flags & M_PKTHDR) != 0) { 1202 len = m0->m_pkthdr.len; 1203 } else { 1204 struct mbuf *m; 1205 1206 for (m = m0, len = 0; m != NULL; m = m->m_next) 1207 len += m->m_len; 1208 } 1209 return len; 1210} 1211 1212 1213/* ------------------------------------------------------------------------ */ 1214/* Function: ipf_pullup */ 1215/* Returns: NULL == pullup failed, else pointer to protocol header */ 1216/* Parameters: xmin(I)- pointer to buffer where data packet starts */ 1217/* fin(I) - pointer to packet information */ 1218/* len(I) - number of bytes to pullup */ 1219/* */ 1220/* Attempt to move at least len bytes (from the start of the buffer) into a */ 1221/* single buffer for ease of access. Operating system native functions are */ 1222/* used to manage buffers - if necessary. If the entire packet ends up in */ 1223/* a single buffer, set the FI_COALESCE flag even though ipf_coalesce() has */ 1224/* not been called. Both fin_ip and fin_dp are updated before exiting _IF_ */ 1225/* and ONLY if the pullup succeeds. */ 1226/* */ 1227/* We assume that 'xmin' is a pointer to a buffer that is part of the chain */ 1228/* of buffers that starts at *fin->fin_mp. */ 1229/* ------------------------------------------------------------------------ */ 1230void * 1231ipf_pullup(xmin, fin, len) 1232 mb_t *xmin; 1233 fr_info_t *fin; 1234 int len; 1235{ 1236 int dpoff, ipoff; 1237 mb_t *m = xmin; 1238 char *ip; 1239 1240 if (m == NULL) 1241 return NULL; 1242 1243 ip = (char *)fin->fin_ip; 1244 if ((fin->fin_flx & FI_COALESCE) != 0) 1245 return ip; 1246 1247 ipoff = fin->fin_ipoff; 1248 if (fin->fin_dp != NULL) 1249 dpoff = (char *)fin->fin_dp - (char *)ip; 1250 else 1251 dpoff = 0; 1252 1253 if (M_LEN(m) < len) { 1254 mb_t *n = *fin->fin_mp; 1255 /* 1256 * Assume that M_PKTHDR is set and just work with what is left 1257 * rather than check.. 1258 * Should not make any real difference, anyway. 1259 */ 1260 if (m != n) { 1261 /* 1262 * Record the mbuf that points to the mbuf that we're 1263 * about to go to work on so that we can update the 1264 * m_next appropriately later. 1265 */ 1266 for (; n->m_next != m; n = n->m_next) 1267 ; 1268 } else { 1269 n = NULL; 1270 } 1271 1272#ifdef MHLEN 1273 if (len > MHLEN) 1274#else 1275 if (len > MLEN) 1276#endif 1277 { 1278#ifdef HAVE_M_PULLDOWN 1279 if (m_pulldown(m, 0, len, NULL) == NULL) 1280 m = NULL; 1281#else 1282 FREE_MB_T(*fin->fin_mp); 1283 m = NULL; 1284 n = NULL; 1285#endif 1286 } else 1287 { 1288 m = m_pullup(m, len); 1289 } 1290 if (n != NULL) 1291 n->m_next = m; 1292 if (m == NULL) { 1293 /* 1294 * When n is non-NULL, it indicates that m pointed to 1295 * a sub-chain (tail) of the mbuf and that the head 1296 * of this chain has not yet been free'd. 1297 */ 1298 if (n != NULL) { 1299 FREE_MB_T(*fin->fin_mp); 1300 } 1301 1302 *fin->fin_mp = NULL; 1303 fin->fin_m = NULL; 1304 return NULL; 1305 } 1306 1307 if (n == NULL) 1308 *fin->fin_mp = m; 1309 1310 while (M_LEN(m) == 0) { 1311 m = m->m_next; 1312 } 1313 fin->fin_m = m; 1314 ip = MTOD(m, char *) + ipoff; 1315 1316 fin->fin_ip = (ip_t *)ip; 1317 if (fin->fin_dp != NULL) 1318 fin->fin_dp = (char *)fin->fin_ip + dpoff; 1319 if (fin->fin_fraghdr != NULL) 1320 fin->fin_fraghdr = (char *)ip + 1321 ((char *)fin->fin_fraghdr - 1322 (char *)fin->fin_ip); 1323 } 1324 1325 if (len == fin->fin_plen) 1326 fin->fin_flx |= FI_COALESCE; 1327 return ip; 1328} 1329 1330 1331int 1332ipf_inject(fin, m) 1333 fr_info_t *fin; 1334 mb_t *m; 1335{ 1336 int error = 0; 1337 1338 if (fin->fin_out == 0) { 1339 netisr_dispatch(NETISR_IP, m); 1340 } else { 1341 fin->fin_ip->ip_len = ntohs(fin->fin_ip->ip_len); 1342 fin->fin_ip->ip_off = ntohs(fin->fin_ip->ip_off); 1343 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 1344 } 1345 1346 return error; 1347} 1348 1349int ipf_pfil_unhook(void) { 1350#if defined(NETBSD_PF) && (__FreeBSD_version >= 500011) 1351 struct pfil_head *ph_inet; 1352# ifdef USE_INET6 1353 struct pfil_head *ph_inet6; 1354# endif 1355#endif 1356 1357#ifdef NETBSD_PF 1358 ph_inet = pfil_head_get(PFIL_TYPE_AF, AF_INET); 1359 if (ph_inet != NULL) 1360 pfil_remove_hook((void *)ipf_check_wrapper, NULL, 1361 PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet); 1362# ifdef USE_INET6 1363 ph_inet6 = pfil_head_get(PFIL_TYPE_AF, AF_INET6); 1364 if (ph_inet6 != NULL) 1365 pfil_remove_hook((void *)ipf_check_wrapper6, NULL, 1366 PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet6); 1367# endif 1368#endif 1369 1370 return (0); 1371} 1372 1373int ipf_pfil_hook(void) { 1374#if defined(NETBSD_PF) && (__FreeBSD_version >= 500011) 1375 struct pfil_head *ph_inet; 1376# ifdef USE_INET6 1377 struct pfil_head *ph_inet6; 1378# endif 1379#endif 1380 1381# ifdef NETBSD_PF 1382 ph_inet = pfil_head_get(PFIL_TYPE_AF, AF_INET); 1383# ifdef USE_INET6 1384 ph_inet6 = pfil_head_get(PFIL_TYPE_AF, AF_INET6); 1385# endif 1386 if (ph_inet == NULL 1387# ifdef USE_INET6 1388 && ph_inet6 == NULL 1389# endif 1390 ) { 1391 return ENODEV; 1392 } 1393 1394 if (ph_inet != NULL) 1395 pfil_add_hook((void *)ipf_check_wrapper, NULL, 1396 PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet); 1397# ifdef USE_INET6 1398 if (ph_inet6 != NULL) 1399 pfil_add_hook((void *)ipf_check_wrapper6, NULL, 1400 PFIL_IN|PFIL_OUT|PFIL_WAITOK, ph_inet6); 1401# endif 1402# endif 1403 return (0); 1404} 1405 1406void 1407ipf_event_reg(void) 1408{ 1409 ipf_arrivetag = EVENTHANDLER_REGISTER(ifnet_arrival_event, \ 1410 ipf_ifevent, &ipfmain, \ 1411 EVENTHANDLER_PRI_ANY); 1412 ipf_departtag = EVENTHANDLER_REGISTER(ifnet_departure_event, \ 1413 ipf_ifevent, &ipfmain, \ 1414 EVENTHANDLER_PRI_ANY); 1415 ipf_clonetag = EVENTHANDLER_REGISTER(if_clone_event, ipf_ifevent, \ 1416 &ipfmain, EVENTHANDLER_PRI_ANY); 1417} 1418 1419void 1420ipf_event_dereg(void) 1421{ 1422 if (ipf_arrivetag != NULL) { 1423 EVENTHANDLER_DEREGISTER(ifnet_arrival_event, ipf_arrivetag); 1424 } 1425 if (ipf_departtag != NULL) { 1426 EVENTHANDLER_DEREGISTER(ifnet_departure_event, ipf_departtag); 1427 } 1428 if (ipf_clonetag != NULL) { 1429 EVENTHANDLER_DEREGISTER(if_clone_event, ipf_clonetag); 1430 } 1431} 1432 1433 1434u_32_t 1435ipf_random() 1436{ 1437 return arc4random(); 1438} 1439 1440 1441u_int 1442ipf_pcksum(fin, hlen, sum) 1443 fr_info_t *fin; 1444 int hlen; 1445 u_int sum; 1446{ 1447 struct mbuf *m; 1448 u_int sum2; 1449 int off; 1450 1451 m = fin->fin_m; 1452 off = (char *)fin->fin_dp - (char *)fin->fin_ip; 1453 m->m_data += hlen; 1454 m->m_len -= hlen; 1455 sum2 = in_cksum(fin->fin_m, fin->fin_plen - off); 1456 m->m_len += hlen; 1457 m->m_data -= hlen; 1458 1459 /* 1460 * Both sum and sum2 are partial sums, so combine them together. 1461 */ 1462 sum += ~sum2 & 0xffff; 1463 while (sum > 0xffff) 1464 sum = (sum & 0xffff) + (sum >> 16); 1465 sum2 = ~sum & 0xffff; 1466 return sum2; 1467}
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