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Annotation of src/sys/netinet/ip_input.c, Revision 1.137

1.137   ! thorpej     1: /*     $NetBSD: ip_input.c,v 1.136 2001/08/06 10:25:00 itojun Exp $    */
1.89      itojun      2:
                      3: /*
                      4:  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
                      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:  * 3. Neither the name of the project nor the names of its contributors
                     16:  *    may be used to endorse or promote products derived from this software
                     17:  *    without specific prior written permission.
                     18:  *
                     19:  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
                     20:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     21:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     22:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
                     23:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     24:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     25:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     26:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     27:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     28:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     29:  * SUCH DAMAGE.
                     30:  */
1.76      thorpej    31:
                     32: /*-
                     33:  * Copyright (c) 1998 The NetBSD Foundation, Inc.
                     34:  * All rights reserved.
                     35:  *
                     36:  * This code is derived from software contributed to The NetBSD Foundation
                     37:  * by Public Access Networks Corporation ("Panix").  It was developed under
                     38:  * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
                     39:  *
                     40:  * Redistribution and use in source and binary forms, with or without
                     41:  * modification, are permitted provided that the following conditions
                     42:  * are met:
                     43:  * 1. Redistributions of source code must retain the above copyright
                     44:  *    notice, this list of conditions and the following disclaimer.
                     45:  * 2. Redistributions in binary form must reproduce the above copyright
                     46:  *    notice, this list of conditions and the following disclaimer in the
                     47:  *    documentation and/or other materials provided with the distribution.
                     48:  * 3. All advertising materials mentioning features or use of this software
                     49:  *    must display the following acknowledgement:
                     50:  *     This product includes software developed by the NetBSD
                     51:  *     Foundation, Inc. and its contributors.
                     52:  * 4. Neither the name of The NetBSD Foundation nor the names of its
                     53:  *    contributors may be used to endorse or promote products derived
                     54:  *    from this software without specific prior written permission.
                     55:  *
                     56:  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
                     57:  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
                     58:  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
                     59:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
                     60:  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
                     61:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
                     62:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
                     63:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
                     64:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
                     65:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
                     66:  * POSSIBILITY OF SUCH DAMAGE.
                     67:  */
1.14      cgd        68:
1.1       cgd        69: /*
1.13      mycroft    70:  * Copyright (c) 1982, 1986, 1988, 1993
                     71:  *     The Regents of the University of California.  All rights reserved.
1.1       cgd        72:  *
                     73:  * Redistribution and use in source and binary forms, with or without
                     74:  * modification, are permitted provided that the following conditions
                     75:  * are met:
                     76:  * 1. Redistributions of source code must retain the above copyright
                     77:  *    notice, this list of conditions and the following disclaimer.
                     78:  * 2. Redistributions in binary form must reproduce the above copyright
                     79:  *    notice, this list of conditions and the following disclaimer in the
                     80:  *    documentation and/or other materials provided with the distribution.
                     81:  * 3. All advertising materials mentioning features or use of this software
                     82:  *    must display the following acknowledgement:
                     83:  *     This product includes software developed by the University of
                     84:  *     California, Berkeley and its contributors.
                     85:  * 4. Neither the name of the University nor the names of its contributors
                     86:  *    may be used to endorse or promote products derived from this software
                     87:  *    without specific prior written permission.
                     88:  *
                     89:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     90:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     91:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     92:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     93:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     94:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     95:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     96:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     97:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     98:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     99:  * SUCH DAMAGE.
                    100:  *
1.14      cgd       101:  *     @(#)ip_input.c  8.2 (Berkeley) 1/4/94
1.1       cgd       102:  */
1.55      scottr    103:
1.62      matt      104: #include "opt_gateway.h"
1.69      mrg       105: #include "opt_pfil_hooks.h"
1.91      thorpej   106: #include "opt_ipsec.h"
1.55      scottr    107: #include "opt_mrouting.h"
1.135     thorpej   108: #include "opt_inet_csum.h"
1.1       cgd       109:
1.5       mycroft   110: #include <sys/param.h>
                    111: #include <sys/systm.h>
                    112: #include <sys/malloc.h>
                    113: #include <sys/mbuf.h>
                    114: #include <sys/domain.h>
                    115: #include <sys/protosw.h>
                    116: #include <sys/socket.h>
1.44      thorpej   117: #include <sys/socketvar.h>
1.5       mycroft   118: #include <sys/errno.h>
                    119: #include <sys/time.h>
                    120: #include <sys/kernel.h>
1.28      christos  121: #include <sys/proc.h>
1.72      thorpej   122: #include <sys/pool.h>
1.28      christos  123:
1.115     mrg       124: #include <uvm/uvm_extern.h>
                    125:
1.28      christos  126: #include <sys/sysctl.h>
1.1       cgd       127:
1.5       mycroft   128: #include <net/if.h>
1.44      thorpej   129: #include <net/if_dl.h>
1.5       mycroft   130: #include <net/route.h>
1.45      mrg       131: #include <net/pfil.h>
1.1       cgd       132:
1.5       mycroft   133: #include <netinet/in.h>
                    134: #include <netinet/in_systm.h>
                    135: #include <netinet/ip.h>
                    136: #include <netinet/in_pcb.h>
                    137: #include <netinet/in_var.h>
                    138: #include <netinet/ip_var.h>
                    139: #include <netinet/ip_icmp.h>
1.89      itojun    140: /* just for gif_ttl */
                    141: #include <netinet/in_gif.h>
                    142: #include "gif.h"
1.111     jdolecek  143:
                    144: #ifdef MROUTING
                    145: #include <netinet/ip_mroute.h>
                    146: #endif
1.89      itojun    147:
                    148: #ifdef IPSEC
                    149: #include <netinet6/ipsec.h>
                    150: #include <netkey/key.h>
                    151: #endif
1.44      thorpej   152:
1.1       cgd       153: #ifndef        IPFORWARDING
                    154: #ifdef GATEWAY
                    155: #define        IPFORWARDING    1       /* forward IP packets not for us */
                    156: #else /* GATEWAY */
                    157: #define        IPFORWARDING    0       /* don't forward IP packets not for us */
                    158: #endif /* GATEWAY */
                    159: #endif /* IPFORWARDING */
                    160: #ifndef        IPSENDREDIRECTS
                    161: #define        IPSENDREDIRECTS 1
                    162: #endif
1.26      thorpej   163: #ifndef IPFORWSRCRT
1.47      cjs       164: #define        IPFORWSRCRT     1       /* forward source-routed packets */
                    165: #endif
                    166: #ifndef IPALLOWSRCRT
1.48      mrg       167: #define        IPALLOWSRCRT    1       /* allow source-routed packets */
1.26      thorpej   168: #endif
1.53      kml       169: #ifndef IPMTUDISC
                    170: #define IPMTUDISC      0
                    171: #endif
1.60      kml       172: #ifndef IPMTUDISCTIMEOUT
1.61      kml       173: #define IPMTUDISCTIMEOUT (10 * 60)     /* as per RFC 1191 */
1.60      kml       174: #endif
1.53      kml       175:
1.27      thorpej   176: /*
                    177:  * Note: DIRECTED_BROADCAST is handled this way so that previous
                    178:  * configuration using this option will Just Work.
                    179:  */
                    180: #ifndef IPDIRECTEDBCAST
                    181: #ifdef DIRECTED_BROADCAST
                    182: #define IPDIRECTEDBCAST        1
                    183: #else
                    184: #define        IPDIRECTEDBCAST 0
                    185: #endif /* DIRECTED_BROADCAST */
                    186: #endif /* IPDIRECTEDBCAST */
1.1       cgd       187: int    ipforwarding = IPFORWARDING;
                    188: int    ipsendredirects = IPSENDREDIRECTS;
1.13      mycroft   189: int    ip_defttl = IPDEFTTL;
1.26      thorpej   190: int    ip_forwsrcrt = IPFORWSRCRT;
1.27      thorpej   191: int    ip_directedbcast = IPDIRECTEDBCAST;
1.47      cjs       192: int    ip_allowsrcrt = IPALLOWSRCRT;
1.53      kml       193: int    ip_mtudisc = IPMTUDISC;
1.60      kml       194: u_int  ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
1.1       cgd       195: #ifdef DIAGNOSTIC
                    196: int    ipprintfs = 0;
                    197: #endif
                    198:
1.60      kml       199: struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
                    200:
1.1       cgd       201: extern struct domain inetdomain;
                    202: int    ipqmaxlen = IFQ_MAXLEN;
1.22      mycroft   203: struct in_ifaddrhead in_ifaddr;
1.57      tls       204: struct in_ifaddrhashhead *in_ifaddrhashtbl;
1.13      mycroft   205: struct ifqueue ipintrq;
1.63      matt      206: struct ipstat  ipstat;
                    207: u_int16_t      ip_id;
1.75      thorpej   208:
1.121     thorpej   209: #ifdef PFIL_HOOKS
                    210: struct pfil_head inet_pfil_hook;
                    211: #endif
                    212:
1.63      matt      213: struct ipqhead ipq;
1.75      thorpej   214: int    ipq_locked;
1.131     itojun    215: int    ip_nfragpackets = 0;
1.133     itojun    216: int    ip_maxfragpackets = 200;
1.75      thorpej   217:
                    218: static __inline int ipq_lock_try __P((void));
                    219: static __inline void ipq_unlock __P((void));
                    220:
                    221: static __inline int
                    222: ipq_lock_try()
                    223: {
                    224:        int s;
                    225:
1.132     thorpej   226:        /*
                    227:         * Use splvm() -- we're bloking things that would cause
                    228:         * mbuf allocation.
                    229:         */
                    230:        s = splvm();
1.75      thorpej   231:        if (ipq_locked) {
                    232:                splx(s);
                    233:                return (0);
                    234:        }
                    235:        ipq_locked = 1;
                    236:        splx(s);
                    237:        return (1);
                    238: }
                    239:
                    240: static __inline void
                    241: ipq_unlock()
                    242: {
                    243:        int s;
                    244:
1.132     thorpej   245:        s = splvm();
1.75      thorpej   246:        ipq_locked = 0;
                    247:        splx(s);
                    248: }
                    249:
                    250: #ifdef DIAGNOSTIC
                    251: #define        IPQ_LOCK()                                                      \
                    252: do {                                                                   \
                    253:        if (ipq_lock_try() == 0) {                                      \
                    254:                printf("%s:%d: ipq already locked\n", __FILE__, __LINE__); \
                    255:                panic("ipq_lock");                                      \
                    256:        }                                                               \
                    257: } while (0)
                    258: #define        IPQ_LOCK_CHECK()                                                \
                    259: do {                                                                   \
                    260:        if (ipq_locked == 0) {                                          \
                    261:                printf("%s:%d: ipq lock not held\n", __FILE__, __LINE__); \
                    262:                panic("ipq lock check");                                \
                    263:        }                                                               \
                    264: } while (0)
                    265: #else
                    266: #define        IPQ_LOCK()              (void) ipq_lock_try()
                    267: #define        IPQ_LOCK_CHECK()        /* nothing */
                    268: #endif
                    269:
                    270: #define        IPQ_UNLOCK()            ipq_unlock()
1.1       cgd       271:
1.72      thorpej   272: struct pool ipqent_pool;
                    273:
1.135     thorpej   274: #ifdef INET_CSUM_COUNTERS
                    275: #include <sys/device.h>
                    276:
                    277: struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
                    278:     NULL, "inet", "hwcsum bad");
                    279: struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
                    280:     NULL, "inet", "hwcsum ok");
                    281: struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
                    282:     NULL, "inet", "swcsum");
                    283:
                    284: #define        INET_CSUM_COUNTER_INCR(ev)      (ev)->ev_count++
                    285:
                    286: #else
                    287:
                    288: #define        INET_CSUM_COUNTER_INCR(ev)      /* nothing */
                    289:
                    290: #endif /* INET_CSUM_COUNTERS */
                    291:
1.1       cgd       292: /*
                    293:  * We need to save the IP options in case a protocol wants to respond
                    294:  * to an incoming packet over the same route if the packet got here
                    295:  * using IP source routing.  This allows connection establishment and
                    296:  * maintenance when the remote end is on a network that is not known
                    297:  * to us.
                    298:  */
                    299: int    ip_nhops = 0;
                    300: static struct ip_srcrt {
                    301:        struct  in_addr dst;                    /* final destination */
                    302:        char    nop;                            /* one NOP to align */
                    303:        char    srcopt[IPOPT_OFFSET + 1];       /* OPTVAL, OLEN and OFFSET */
                    304:        struct  in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
                    305: } ip_srcrt;
                    306:
1.13      mycroft   307: static void save_rte __P((u_char *, struct in_addr));
1.35      mycroft   308:
1.1       cgd       309: /*
                    310:  * IP initialization: fill in IP protocol switch table.
                    311:  * All protocols not implemented in kernel go to raw IP protocol handler.
                    312:  */
1.8       mycroft   313: void
1.1       cgd       314: ip_init()
                    315: {
1.109     augustss  316:        struct protosw *pr;
                    317:        int i;
1.1       cgd       318:
1.72      thorpej   319:        pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl",
                    320:            0, NULL, NULL, M_IPQ);
                    321:
1.1       cgd       322:        pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
                    323:        if (pr == 0)
                    324:                panic("ip_init");
                    325:        for (i = 0; i < IPPROTO_MAX; i++)
                    326:                ip_protox[i] = pr - inetsw;
                    327:        for (pr = inetdomain.dom_protosw;
                    328:            pr < inetdomain.dom_protoswNPROTOSW; pr++)
                    329:                if (pr->pr_domain->dom_family == PF_INET &&
                    330:                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
                    331:                        ip_protox[pr->pr_protocol] = pr - inetsw;
1.25      cgd       332:        LIST_INIT(&ipq);
1.1       cgd       333:        ip_id = time.tv_sec & 0xffff;
                    334:        ipintrq.ifq_maxlen = ipqmaxlen;
1.22      mycroft   335:        TAILQ_INIT(&in_ifaddr);
1.120     ad        336:        in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IFADDR,
                    337:            M_WAITOK, &in_ifaddrhash);
1.60      kml       338:        if (ip_mtudisc != 0)
                    339:                ip_mtudisc_timeout_q =
                    340:                    rt_timer_queue_create(ip_mtudisc_timeout);
1.73      thorpej   341: #ifdef GATEWAY
                    342:        ipflow_init();
                    343: #endif
1.121     thorpej   344:
                    345: #ifdef PFIL_HOOKS
                    346:        /* Register our Packet Filter hook. */
1.126     thorpej   347:        inet_pfil_hook.ph_type = PFIL_TYPE_AF;
                    348:        inet_pfil_hook.ph_af   = AF_INET;
1.121     thorpej   349:        i = pfil_head_register(&inet_pfil_hook);
                    350:        if (i != 0)
                    351:                printf("ip_init: WARNING: unable to register pfil hook, "
                    352:                    "error %d\n", i);
                    353: #endif /* PFIL_HOOKS */
1.135     thorpej   354:
                    355: #ifdef INET_CSUM_COUNTERS
                    356:        evcnt_attach_static(&ip_hwcsum_bad);
                    357:        evcnt_attach_static(&ip_hwcsum_ok);
                    358:        evcnt_attach_static(&ip_swcsum);
                    359: #endif /* INET_CSUM_COUNTERS */
1.1       cgd       360: }
                    361:
                    362: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    363: struct route ipforward_rt;
                    364:
                    365: /*
1.89      itojun    366:  * IP software interrupt routine
                    367:  */
                    368: void
                    369: ipintr()
                    370: {
                    371:        int s;
                    372:        struct mbuf *m;
                    373:
                    374:        while (1) {
1.132     thorpej   375:                s = splnet();
1.89      itojun    376:                IF_DEQUEUE(&ipintrq, m);
                    377:                splx(s);
                    378:                if (m == 0)
                    379:                        return;
                    380:                ip_input(m);
                    381:        }
                    382: }
                    383:
                    384: /*
1.1       cgd       385:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    386:  * try to reassemble.  Process options.  Pass to next level.
                    387:  */
1.8       mycroft   388: void
1.89      itojun    389: ip_input(struct mbuf *m)
1.1       cgd       390: {
1.109     augustss  391:        struct ip *ip = NULL;
                    392:        struct ipq *fp;
                    393:        struct in_ifaddr *ia;
                    394:        struct ifaddr *ifa;
1.25      cgd       395:        struct ipqent *ipqe;
1.89      itojun    396:        int hlen = 0, mff, len;
1.100     itojun    397:        int downmatch;
1.1       cgd       398:
                    399: #ifdef DIAGNOSTIC
                    400:        if ((m->m_flags & M_PKTHDR) == 0)
                    401:                panic("ipintr no HDR");
                    402: #endif
1.89      itojun    403: #ifdef IPSEC
                    404:        /*
                    405:         * should the inner packet be considered authentic?
                    406:         * see comment in ah4_input().
                    407:         */
                    408:        if (m) {
                    409:                m->m_flags &= ~M_AUTHIPHDR;
                    410:                m->m_flags &= ~M_AUTHIPDGM;
                    411:        }
                    412: #endif
1.1       cgd       413:        /*
                    414:         * If no IP addresses have been set yet but the interfaces
                    415:         * are receiving, can't do anything with incoming packets yet.
                    416:         */
1.22      mycroft   417:        if (in_ifaddr.tqh_first == 0)
1.1       cgd       418:                goto bad;
                    419:        ipstat.ips_total++;
                    420:        if (m->m_len < sizeof (struct ip) &&
                    421:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    422:                ipstat.ips_toosmall++;
1.89      itojun    423:                return;
1.1       cgd       424:        }
                    425:        ip = mtod(m, struct ip *);
1.13      mycroft   426:        if (ip->ip_v != IPVERSION) {
                    427:                ipstat.ips_badvers++;
                    428:                goto bad;
                    429:        }
1.1       cgd       430:        hlen = ip->ip_hl << 2;
                    431:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    432:                ipstat.ips_badhlen++;
                    433:                goto bad;
                    434:        }
                    435:        if (hlen > m->m_len) {
                    436:                if ((m = m_pullup(m, hlen)) == 0) {
                    437:                        ipstat.ips_badhlen++;
1.89      itojun    438:                        return;
1.1       cgd       439:                }
                    440:                ip = mtod(m, struct ip *);
                    441:        }
1.98      thorpej   442:
1.85      hwr       443:        /*
1.99      thorpej   444:         * RFC1122: packets with a multicast source address are
1.98      thorpej   445:         * not allowed.
1.85      hwr       446:         */
                    447:        if (IN_MULTICAST(ip->ip_src.s_addr)) {
1.130     itojun    448:                ipstat.ips_badaddr++;
1.85      hwr       449:                goto bad;
1.129     itojun    450:        }
                    451:
                    452:        /* 127/8 must not appear on wire - RFC1122 */
                    453:        if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
                    454:            (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
1.130     itojun    455:                if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
                    456:                        ipstat.ips_badaddr++;
1.129     itojun    457:                        goto bad;
1.130     itojun    458:                }
1.85      hwr       459:        }
                    460:
1.135     thorpej   461:        switch (m->m_pkthdr.csum_flags &
1.137   ! thorpej   462:                ((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) |
1.135     thorpej   463:                 M_CSUM_IPv4_BAD)) {
                    464:        case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
                    465:                INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
                    466:                goto badcsum;
                    467:
                    468:        case M_CSUM_IPv4:
                    469:                /* Checksum was okay. */
                    470:                INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
                    471:                break;
                    472:
                    473:        default:
                    474:                /* Must compute it ourselves. */
                    475:                INET_CSUM_COUNTER_INCR(&ip_swcsum);
                    476:                if (in_cksum(m, hlen) != 0)
                    477:                        goto bad;
                    478:                break;
1.1       cgd       479:        }
                    480:
1.121     thorpej   481:        /* Retrieve the packet length. */
                    482:        len = ntohs(ip->ip_len);
1.81      proff     483:
                    484:        /*
                    485:         * Check for additional length bogosity
                    486:         */
1.84      proff     487:        if (len < hlen) {
1.81      proff     488:                ipstat.ips_badlen++;
                    489:                goto bad;
                    490:        }
1.1       cgd       491:
                    492:        /*
                    493:         * Check that the amount of data in the buffers
                    494:         * is as at least much as the IP header would have us expect.
                    495:         * Trim mbufs if longer than we expect.
                    496:         * Drop packet if shorter than we expect.
                    497:         */
1.35      mycroft   498:        if (m->m_pkthdr.len < len) {
1.1       cgd       499:                ipstat.ips_tooshort++;
                    500:                goto bad;
                    501:        }
1.35      mycroft   502:        if (m->m_pkthdr.len > len) {
1.1       cgd       503:                if (m->m_len == m->m_pkthdr.len) {
1.35      mycroft   504:                        m->m_len = len;
                    505:                        m->m_pkthdr.len = len;
1.1       cgd       506:                } else
1.35      mycroft   507:                        m_adj(m, len - m->m_pkthdr.len);
1.1       cgd       508:        }
                    509:
1.94      itojun    510: #ifdef IPSEC
                    511:        /* ipflow (IP fast fowarding) is not compatible with IPsec. */
                    512:        m->m_flags &= ~M_CANFASTFWD;
                    513: #else
1.64      thorpej   514:        /*
                    515:         * Assume that we can create a fast-forward IP flow entry
                    516:         * based on this packet.
                    517:         */
                    518:        m->m_flags |= M_CANFASTFWD;
1.94      itojun    519: #endif
1.64      thorpej   520:
1.36      mrg       521: #ifdef PFIL_HOOKS
1.33      mrg       522:        /*
1.64      thorpej   523:         * Run through list of hooks for input packets.  If there are any
                    524:         * filters which require that additional packets in the flow are
                    525:         * not fast-forwarded, they must clear the M_CANFASTFWD flag.
                    526:         * Note that filters must _never_ set this flag, as another filter
                    527:         * in the list may have previously cleared it.
1.33      mrg       528:         */
1.127     itojun    529:        /*
                    530:         * let ipfilter look at packet on the wire,
                    531:         * not the decapsulated packet.
                    532:         */
                    533: #ifdef IPSEC
1.136     itojun    534:        if (!ipsec_getnhist(m))
1.127     itojun    535: #else
                    536:        if (1)
                    537: #endif
                    538:        {
                    539:                if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif,
                    540:                                   PFIL_IN) != 0)
1.121     thorpej   541:                return;
1.127     itojun    542:                if (m == NULL)
                    543:                        return;
                    544:                ip = mtod(m, struct ip *);
                    545:        }
1.36      mrg       546: #endif /* PFIL_HOOKS */
1.123     thorpej   547:
                    548: #ifdef ALTQ
                    549:        /* XXX Temporary until ALTQ is changed to use a pfil hook */
                    550:        if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) {
                    551:                /* packet dropped by traffic conditioner */
                    552:                return;
                    553:        }
                    554: #endif
1.121     thorpej   555:
                    556:        /*
                    557:         * Convert fields to host representation.
                    558:         */
                    559:        NTOHS(ip->ip_len);
                    560:        NTOHS(ip->ip_off);
1.33      mrg       561:
1.1       cgd       562:        /*
                    563:         * Process options and, if not destined for us,
                    564:         * ship it on.  ip_dooptions returns 1 when an
                    565:         * error was detected (causing an icmp message
                    566:         * to be sent and the original packet to be freed).
                    567:         */
                    568:        ip_nhops = 0;           /* for source routed packets */
                    569:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
1.89      itojun    570:                return;
1.1       cgd       571:
                    572:        /*
                    573:         * Check our list of addresses, to see if the packet is for us.
1.100     itojun    574:         *
                    575:         * Traditional 4.4BSD did not consult IFF_UP at all.
                    576:         * The behavior here is to treat addresses on !IFF_UP interface
                    577:         * as not mine.
1.1       cgd       578:         */
1.100     itojun    579:        downmatch = 0;
1.97      itojun    580:        for (ia = IN_IFADDR_HASH(ip->ip_dst.s_addr).lh_first;
                    581:             ia != NULL;
                    582:             ia = ia->ia_hash.le_next) {
                    583:                if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
                    584:                        if ((ia->ia_ifp->if_flags & IFF_UP) != 0)
                    585:                                break;
1.100     itojun    586:                        else
                    587:                                downmatch++;
1.97      itojun    588:                }
                    589:        }
1.86      thorpej   590:        if (ia != NULL)
                    591:                goto ours;
1.57      tls       592:        if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
                    593:                for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first;
                    594:                    ifa != NULL; ifa = ifa->ifa_list.tqe_next) {
                    595:                        if (ifa->ifa_addr->sa_family != AF_INET) continue;
                    596:                        ia = ifatoia(ifa);
1.35      mycroft   597:                        if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
                    598:                            in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
1.20      mycroft   599:                            /*
                    600:                             * Look for all-0's host part (old broadcast addr),
                    601:                             * either for subnet or net.
                    602:                             */
                    603:                            ip->ip_dst.s_addr == ia->ia_subnet ||
1.18      mycroft   604:                            ip->ip_dst.s_addr == ia->ia_net)
1.1       cgd       605:                                goto ours;
1.57      tls       606:                        /*
                    607:                         * An interface with IP address zero accepts
                    608:                         * all packets that arrive on that interface.
                    609:                         */
                    610:                        if (in_nullhost(ia->ia_addr.sin_addr))
                    611:                                goto ours;
1.1       cgd       612:                }
                    613:        }
1.18      mycroft   614:        if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4       hpeyerl   615:                struct in_multi *inm;
                    616: #ifdef MROUTING
                    617:                extern struct socket *ip_mrouter;
1.10      brezak    618:
                    619:                if (m->m_flags & M_EXT) {
                    620:                        if ((m = m_pullup(m, hlen)) == 0) {
                    621:                                ipstat.ips_toosmall++;
1.89      itojun    622:                                return;
1.10      brezak    623:                        }
                    624:                        ip = mtod(m, struct ip *);
                    625:                }
1.4       hpeyerl   626:
                    627:                if (ip_mrouter) {
                    628:                        /*
                    629:                         * If we are acting as a multicast router, all
                    630:                         * incoming multicast packets are passed to the
                    631:                         * kernel-level multicast forwarding function.
                    632:                         * The packet is returned (relatively) intact; if
                    633:                         * ip_mforward() returns a non-zero value, the packet
                    634:                         * must be discarded, else it may be accepted below.
                    635:                         *
                    636:                         * (The IP ident field is put in the same byte order
                    637:                         * as expected when ip_mforward() is called from
                    638:                         * ip_output().)
                    639:                         */
1.13      mycroft   640:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    641:                                ipstat.ips_cantforward++;
1.4       hpeyerl   642:                                m_freem(m);
1.89      itojun    643:                                return;
1.4       hpeyerl   644:                        }
                    645:
                    646:                        /*
                    647:                         * The process-level routing demon needs to receive
                    648:                         * all multicast IGMP packets, whether or not this
                    649:                         * host belongs to their destination groups.
                    650:                         */
                    651:                        if (ip->ip_p == IPPROTO_IGMP)
                    652:                                goto ours;
1.13      mycroft   653:                        ipstat.ips_forward++;
1.4       hpeyerl   654:                }
                    655: #endif
                    656:                /*
                    657:                 * See if we belong to the destination multicast group on the
                    658:                 * arrival interface.
                    659:                 */
                    660:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    661:                if (inm == NULL) {
1.13      mycroft   662:                        ipstat.ips_cantforward++;
1.4       hpeyerl   663:                        m_freem(m);
1.89      itojun    664:                        return;
1.4       hpeyerl   665:                }
                    666:                goto ours;
                    667:        }
1.19      mycroft   668:        if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
1.35      mycroft   669:            in_nullhost(ip->ip_dst))
1.1       cgd       670:                goto ours;
                    671:
                    672:        /*
                    673:         * Not for us; forward if possible and desirable.
                    674:         */
                    675:        if (ipforwarding == 0) {
                    676:                ipstat.ips_cantforward++;
                    677:                m_freem(m);
1.100     itojun    678:        } else {
                    679:                /*
                    680:                 * If ip_dst matched any of my address on !IFF_UP interface,
                    681:                 * and there's no IFF_UP interface that matches ip_dst,
                    682:                 * send icmp unreach.  Forwarding it will result in in-kernel
                    683:                 * forwarding loop till TTL goes to 0.
                    684:                 */
                    685:                if (downmatch) {
                    686:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
                    687:                        ipstat.ips_cantforward++;
                    688:                        return;
                    689:                }
1.1       cgd       690:                ip_forward(m, 0);
1.100     itojun    691:        }
1.89      itojun    692:        return;
1.1       cgd       693:
                    694: ours:
                    695:        /*
                    696:         * If offset or IP_MF are set, must reassemble.
                    697:         * Otherwise, nothing need be done.
                    698:         * (We could look in the reassembly queue to see
                    699:         * if the packet was previously fragmented,
                    700:         * but it's not worth the time; just let them time out.)
                    701:         */
1.37      perry     702:        if (ip->ip_off & ~(IP_DF|IP_RF)) {
1.1       cgd       703:                /*
                    704:                 * Look for queue of fragments
                    705:                 * of this datagram.
                    706:                 */
1.75      thorpej   707:                IPQ_LOCK();
1.25      cgd       708:                for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1       cgd       709:                        if (ip->ip_id == fp->ipq_id &&
1.35      mycroft   710:                            in_hosteq(ip->ip_src, fp->ipq_src) &&
                    711:                            in_hosteq(ip->ip_dst, fp->ipq_dst) &&
1.1       cgd       712:                            ip->ip_p == fp->ipq_p)
                    713:                                goto found;
                    714:                fp = 0;
                    715: found:
                    716:
                    717:                /*
                    718:                 * Adjust ip_len to not reflect header,
1.25      cgd       719:                 * set ipqe_mff if more fragments are expected,
1.1       cgd       720:                 * convert offset of this to bytes.
                    721:                 */
                    722:                ip->ip_len -= hlen;
1.25      cgd       723:                mff = (ip->ip_off & IP_MF) != 0;
                    724:                if (mff) {
1.16      cgd       725:                        /*
                    726:                         * Make sure that fragments have a data length
                    727:                         * that's a non-zero multiple of 8 bytes.
                    728:                         */
1.17      cgd       729:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16      cgd       730:                                ipstat.ips_badfrags++;
1.75      thorpej   731:                                IPQ_UNLOCK();
1.16      cgd       732:                                goto bad;
                    733:                        }
                    734:                }
1.1       cgd       735:                ip->ip_off <<= 3;
                    736:
                    737:                /*
                    738:                 * If datagram marked as having more fragments
                    739:                 * or if this is not the first fragment,
                    740:                 * attempt reassembly; if it succeeds, proceed.
                    741:                 */
1.25      cgd       742:                if (mff || ip->ip_off) {
1.1       cgd       743:                        ipstat.ips_fragments++;
1.72      thorpej   744:                        ipqe = pool_get(&ipqent_pool, PR_NOWAIT);
1.25      cgd       745:                        if (ipqe == NULL) {
                    746:                                ipstat.ips_rcvmemdrop++;
1.75      thorpej   747:                                IPQ_UNLOCK();
1.25      cgd       748:                                goto bad;
                    749:                        }
                    750:                        ipqe->ipqe_mff = mff;
1.50      thorpej   751:                        ipqe->ipqe_m = m;
1.25      cgd       752:                        ipqe->ipqe_ip = ip;
1.50      thorpej   753:                        m = ip_reass(ipqe, fp);
1.75      thorpej   754:                        if (m == 0) {
                    755:                                IPQ_UNLOCK();
1.89      itojun    756:                                return;
1.75      thorpej   757:                        }
1.13      mycroft   758:                        ipstat.ips_reassembled++;
1.50      thorpej   759:                        ip = mtod(m, struct ip *);
1.74      thorpej   760:                        hlen = ip->ip_hl << 2;
1.79      mycroft   761:                        ip->ip_len += hlen;
1.1       cgd       762:                } else
                    763:                        if (fp)
                    764:                                ip_freef(fp);
1.75      thorpej   765:                IPQ_UNLOCK();
1.79      mycroft   766:        }
1.128     itojun    767:
                    768: #ifdef IPSEC
                    769:        /*
                    770:         * enforce IPsec policy checking if we are seeing last header.
                    771:         * note that we do not visit this with protocols with pcb layer
                    772:         * code - like udp/tcp/raw ip.
                    773:         */
                    774:        if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 &&
                    775:            ipsec4_in_reject(m, NULL)) {
                    776:                ipsecstat.in_polvio++;
                    777:                goto bad;
                    778:        }
                    779: #endif
1.1       cgd       780:
                    781:        /*
                    782:         * Switch out to protocol's input routine.
                    783:         */
1.82      aidan     784: #if IFA_STATS
1.122     itojun    785:        if (ia && ip)
                    786:                ia->ia_ifa.ifa_data.ifad_inbytes += ip->ip_len;
1.82      aidan     787: #endif
1.1       cgd       788:        ipstat.ips_delivered++;
1.89      itojun    789:     {
                    790:        int off = hlen, nh = ip->ip_p;
                    791:
                    792:        (*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
                    793:        return;
                    794:     }
1.1       cgd       795: bad:
                    796:        m_freem(m);
1.135     thorpej   797:        return;
                    798:
                    799: badcsum:
                    800:        ipstat.ips_badsum++;
                    801:        m_freem(m);
1.1       cgd       802: }
                    803:
                    804: /*
                    805:  * Take incoming datagram fragment and try to
                    806:  * reassemble it into whole datagram.  If a chain for
                    807:  * reassembly of this datagram already exists, then it
                    808:  * is given as fp; otherwise have to make a chain.
                    809:  */
1.50      thorpej   810: struct mbuf *
1.25      cgd       811: ip_reass(ipqe, fp)
1.109     augustss  812:        struct ipqent *ipqe;
                    813:        struct ipq *fp;
1.1       cgd       814: {
1.109     augustss  815:        struct mbuf *m = ipqe->ipqe_m;
                    816:        struct ipqent *nq, *p, *q;
1.25      cgd       817:        struct ip *ip;
1.1       cgd       818:        struct mbuf *t;
1.25      cgd       819:        int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1       cgd       820:        int i, next;
                    821:
1.75      thorpej   822:        IPQ_LOCK_CHECK();
                    823:
1.1       cgd       824:        /*
                    825:         * Presence of header sizes in mbufs
                    826:         * would confuse code below.
                    827:         */
                    828:        m->m_data += hlen;
                    829:        m->m_len -= hlen;
                    830:
                    831:        /*
                    832:         * If first fragment to arrive, create a reassembly queue.
                    833:         */
                    834:        if (fp == 0) {
1.131     itojun    835:                /*
                    836:                 * Enforce upper bound on number of fragmented packets
                    837:                 * for which we attempt reassembly;
                    838:                 * If maxfrag is 0, never accept fragments.
                    839:                 * If maxfrag is -1, accept all fragments without limitation.
                    840:                 */
                    841:                if (ip_maxfragpackets < 0)
                    842:                        ;
                    843:                else if (ip_nfragpackets >= ip_maxfragpackets)
                    844:                        goto dropfrag;
                    845:                ip_nfragpackets++;
1.50      thorpej   846:                MALLOC(fp, struct ipq *, sizeof (struct ipq),
                    847:                    M_FTABLE, M_NOWAIT);
                    848:                if (fp == NULL)
1.1       cgd       849:                        goto dropfrag;
1.25      cgd       850:                LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1       cgd       851:                fp->ipq_ttl = IPFRAGTTL;
1.25      cgd       852:                fp->ipq_p = ipqe->ipqe_ip->ip_p;
                    853:                fp->ipq_id = ipqe->ipqe_ip->ip_id;
                    854:                LIST_INIT(&fp->ipq_fragq);
                    855:                fp->ipq_src = ipqe->ipqe_ip->ip_src;
                    856:                fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
                    857:                p = NULL;
1.1       cgd       858:                goto insert;
                    859:        }
                    860:
                    861:        /*
                    862:         * Find a segment which begins after this one does.
                    863:         */
1.25      cgd       864:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    865:            p = q, q = q->ipqe_q.le_next)
                    866:                if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1       cgd       867:                        break;
                    868:
                    869:        /*
                    870:         * If there is a preceding segment, it may provide some of
                    871:         * our data already.  If so, drop the data from the incoming
                    872:         * segment.  If it provides all of our data, drop us.
                    873:         */
1.25      cgd       874:        if (p != NULL) {
                    875:                i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
                    876:                    ipqe->ipqe_ip->ip_off;
1.1       cgd       877:                if (i > 0) {
1.25      cgd       878:                        if (i >= ipqe->ipqe_ip->ip_len)
1.1       cgd       879:                                goto dropfrag;
1.50      thorpej   880:                        m_adj(ipqe->ipqe_m, i);
1.25      cgd       881:                        ipqe->ipqe_ip->ip_off += i;
                    882:                        ipqe->ipqe_ip->ip_len -= i;
1.1       cgd       883:                }
                    884:        }
                    885:
                    886:        /*
                    887:         * While we overlap succeeding segments trim them or,
                    888:         * if they are completely covered, dequeue them.
                    889:         */
1.25      cgd       890:        for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
                    891:            q->ipqe_ip->ip_off; q = nq) {
                    892:                i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
                    893:                    q->ipqe_ip->ip_off;
                    894:                if (i < q->ipqe_ip->ip_len) {
                    895:                        q->ipqe_ip->ip_len -= i;
                    896:                        q->ipqe_ip->ip_off += i;
1.50      thorpej   897:                        m_adj(q->ipqe_m, i);
1.1       cgd       898:                        break;
                    899:                }
1.25      cgd       900:                nq = q->ipqe_q.le_next;
1.50      thorpej   901:                m_freem(q->ipqe_m);
1.25      cgd       902:                LIST_REMOVE(q, ipqe_q);
1.72      thorpej   903:                pool_put(&ipqent_pool, q);
1.1       cgd       904:        }
                    905:
                    906: insert:
                    907:        /*
                    908:         * Stick new segment in its place;
                    909:         * check for complete reassembly.
                    910:         */
1.25      cgd       911:        if (p == NULL) {
                    912:                LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
                    913:        } else {
                    914:                LIST_INSERT_AFTER(p, ipqe, ipqe_q);
                    915:        }
1.1       cgd       916:        next = 0;
1.25      cgd       917:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    918:            p = q, q = q->ipqe_q.le_next) {
                    919:                if (q->ipqe_ip->ip_off != next)
1.1       cgd       920:                        return (0);
1.25      cgd       921:                next += q->ipqe_ip->ip_len;
1.1       cgd       922:        }
1.25      cgd       923:        if (p->ipqe_mff)
1.1       cgd       924:                return (0);
                    925:
                    926:        /*
1.41      thorpej   927:         * Reassembly is complete.  Check for a bogus message size and
                    928:         * concatenate fragments.
1.1       cgd       929:         */
1.25      cgd       930:        q = fp->ipq_fragq.lh_first;
                    931:        ip = q->ipqe_ip;
1.41      thorpej   932:        if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) {
                    933:                ipstat.ips_toolong++;
                    934:                ip_freef(fp);
                    935:                return (0);
                    936:        }
1.50      thorpej   937:        m = q->ipqe_m;
1.1       cgd       938:        t = m->m_next;
                    939:        m->m_next = 0;
                    940:        m_cat(m, t);
1.25      cgd       941:        nq = q->ipqe_q.le_next;
1.72      thorpej   942:        pool_put(&ipqent_pool, q);
1.25      cgd       943:        for (q = nq; q != NULL; q = nq) {
1.50      thorpej   944:                t = q->ipqe_m;
1.25      cgd       945:                nq = q->ipqe_q.le_next;
1.72      thorpej   946:                pool_put(&ipqent_pool, q);
1.1       cgd       947:                m_cat(m, t);
                    948:        }
                    949:
                    950:        /*
                    951:         * Create header for new ip packet by
                    952:         * modifying header of first packet;
                    953:         * dequeue and discard fragment reassembly header.
                    954:         * Make header visible.
                    955:         */
                    956:        ip->ip_len = next;
1.25      cgd       957:        ip->ip_src = fp->ipq_src;
                    958:        ip->ip_dst = fp->ipq_dst;
                    959:        LIST_REMOVE(fp, ipq_q);
1.50      thorpej   960:        FREE(fp, M_FTABLE);
1.131     itojun    961:        ip_nfragpackets--;
1.1       cgd       962:        m->m_len += (ip->ip_hl << 2);
                    963:        m->m_data -= (ip->ip_hl << 2);
                    964:        /* some debugging cruft by sklower, below, will go away soon */
                    965:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
1.109     augustss  966:                int plen = 0;
1.50      thorpej   967:                for (t = m; t; t = t->m_next)
                    968:                        plen += t->m_len;
                    969:                m->m_pkthdr.len = plen;
1.1       cgd       970:        }
1.50      thorpej   971:        return (m);
1.1       cgd       972:
                    973: dropfrag:
                    974:        ipstat.ips_fragdropped++;
                    975:        m_freem(m);
1.72      thorpej   976:        pool_put(&ipqent_pool, ipqe);
1.1       cgd       977:        return (0);
                    978: }
                    979:
                    980: /*
                    981:  * Free a fragment reassembly header and all
                    982:  * associated datagrams.
                    983:  */
1.8       mycroft   984: void
1.1       cgd       985: ip_freef(fp)
                    986:        struct ipq *fp;
                    987: {
1.109     augustss  988:        struct ipqent *q, *p;
1.1       cgd       989:
1.75      thorpej   990:        IPQ_LOCK_CHECK();
                    991:
1.25      cgd       992:        for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
                    993:                p = q->ipqe_q.le_next;
1.50      thorpej   994:                m_freem(q->ipqe_m);
1.25      cgd       995:                LIST_REMOVE(q, ipqe_q);
1.72      thorpej   996:                pool_put(&ipqent_pool, q);
1.1       cgd       997:        }
1.25      cgd       998:        LIST_REMOVE(fp, ipq_q);
1.50      thorpej   999:        FREE(fp, M_FTABLE);
1.131     itojun   1000:        ip_nfragpackets--;
1.1       cgd      1001: }
                   1002:
                   1003: /*
                   1004:  * IP timer processing;
                   1005:  * if a timer expires on a reassembly
                   1006:  * queue, discard it.
                   1007:  */
1.8       mycroft  1008: void
1.1       cgd      1009: ip_slowtimo()
                   1010: {
1.109     augustss 1011:        struct ipq *fp, *nfp;
1.24      mycroft  1012:        int s = splsoftnet();
1.1       cgd      1013:
1.75      thorpej  1014:        IPQ_LOCK();
1.25      cgd      1015:        for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
                   1016:                nfp = fp->ipq_q.le_next;
                   1017:                if (--fp->ipq_ttl == 0) {
1.1       cgd      1018:                        ipstat.ips_fragtimeout++;
1.25      cgd      1019:                        ip_freef(fp);
1.1       cgd      1020:                }
                   1021:        }
1.131     itojun   1022:        /*
                   1023:         * If we are over the maximum number of fragments
                   1024:         * (due to the limit being lowered), drain off
                   1025:         * enough to get down to the new limit.
                   1026:         */
                   1027:        if (ip_maxfragpackets < 0)
                   1028:                ;
                   1029:        else {
                   1030:                while (ip_nfragpackets > ip_maxfragpackets && ipq.lh_first)
                   1031:                        ip_freef(ipq.lh_first);
                   1032:        }
1.75      thorpej  1033:        IPQ_UNLOCK();
1.63      matt     1034: #ifdef GATEWAY
                   1035:        ipflow_slowtimo();
                   1036: #endif
1.1       cgd      1037:        splx(s);
                   1038: }
                   1039:
                   1040: /*
                   1041:  * Drain off all datagram fragments.
                   1042:  */
1.8       mycroft  1043: void
1.1       cgd      1044: ip_drain()
                   1045: {
                   1046:
1.75      thorpej  1047:        /*
                   1048:         * We may be called from a device's interrupt context.  If
                   1049:         * the ipq is already busy, just bail out now.
                   1050:         */
                   1051:        if (ipq_lock_try() == 0)
                   1052:                return;
                   1053:
1.25      cgd      1054:        while (ipq.lh_first != NULL) {
1.1       cgd      1055:                ipstat.ips_fragdropped++;
1.25      cgd      1056:                ip_freef(ipq.lh_first);
1.1       cgd      1057:        }
1.75      thorpej  1058:
                   1059:        IPQ_UNLOCK();
1.1       cgd      1060: }
                   1061:
                   1062: /*
                   1063:  * Do option processing on a datagram,
                   1064:  * possibly discarding it if bad options are encountered,
                   1065:  * or forwarding it if source-routed.
                   1066:  * Returns 1 if packet has been forwarded/freed,
                   1067:  * 0 if the packet should be processed further.
                   1068:  */
1.8       mycroft  1069: int
1.1       cgd      1070: ip_dooptions(m)
                   1071:        struct mbuf *m;
                   1072: {
1.109     augustss 1073:        struct ip *ip = mtod(m, struct ip *);
                   1074:        u_char *cp, *cp0;
                   1075:        struct ip_timestamp *ipt;
                   1076:        struct in_ifaddr *ia;
1.1       cgd      1077:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.104     thorpej  1078:        struct in_addr dst;
1.1       cgd      1079:        n_time ntime;
                   1080:
1.13      mycroft  1081:        dst = ip->ip_dst;
1.1       cgd      1082:        cp = (u_char *)(ip + 1);
                   1083:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                   1084:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                   1085:                opt = cp[IPOPT_OPTVAL];
                   1086:                if (opt == IPOPT_EOL)
                   1087:                        break;
                   1088:                if (opt == IPOPT_NOP)
                   1089:                        optlen = 1;
                   1090:                else {
1.113     itojun   1091:                        if (cnt < IPOPT_OLEN + sizeof(*cp)) {
                   1092:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                   1093:                                goto bad;
                   1094:                        }
1.1       cgd      1095:                        optlen = cp[IPOPT_OLEN];
1.114     itojun   1096:                        if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
1.1       cgd      1097:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                   1098:                                goto bad;
                   1099:                        }
                   1100:                }
                   1101:                switch (opt) {
                   1102:
                   1103:                default:
                   1104:                        break;
                   1105:
                   1106:                /*
                   1107:                 * Source routing with record.
                   1108:                 * Find interface with current destination address.
                   1109:                 * If none on this machine then drop if strictly routed,
                   1110:                 * or do nothing if loosely routed.
                   1111:                 * Record interface address and bring up next address
                   1112:                 * component.  If strictly routed make sure next
                   1113:                 * address is on directly accessible net.
                   1114:                 */
                   1115:                case IPOPT_LSRR:
                   1116:                case IPOPT_SSRR:
1.47      cjs      1117:                        if (ip_allowsrcrt == 0) {
                   1118:                                type = ICMP_UNREACH;
                   1119:                                code = ICMP_UNREACH_NET_PROHIB;
                   1120:                                goto bad;
                   1121:                        }
1.114     itojun   1122:                        if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
                   1123:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                   1124:                                goto bad;
                   1125:                        }
1.1       cgd      1126:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                   1127:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                   1128:                                goto bad;
                   1129:                        }
                   1130:                        ipaddr.sin_addr = ip->ip_dst;
1.19      mycroft  1131:                        ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1       cgd      1132:                        if (ia == 0) {
                   1133:                                if (opt == IPOPT_SSRR) {
                   1134:                                        type = ICMP_UNREACH;
                   1135:                                        code = ICMP_UNREACH_SRCFAIL;
                   1136:                                        goto bad;
                   1137:                                }
                   1138:                                /*
                   1139:                                 * Loose routing, and not at next destination
                   1140:                                 * yet; nothing to do except forward.
                   1141:                                 */
                   1142:                                break;
                   1143:                        }
                   1144:                        off--;                  /* 0 origin */
1.112     sommerfe 1145:                        if ((off + sizeof(struct in_addr)) > optlen) {
1.1       cgd      1146:                                /*
                   1147:                                 * End of source route.  Should be for us.
                   1148:                                 */
                   1149:                                save_rte(cp, ip->ip_src);
                   1150:                                break;
                   1151:                        }
                   1152:                        /*
                   1153:                         * locate outgoing interface
                   1154:                         */
                   1155:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                   1156:                            sizeof(ipaddr.sin_addr));
1.96      thorpej  1157:                        if (opt == IPOPT_SSRR)
                   1158:                                ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
                   1159:                        else
1.1       cgd      1160:                                ia = ip_rtaddr(ipaddr.sin_addr);
                   1161:                        if (ia == 0) {
                   1162:                                type = ICMP_UNREACH;
                   1163:                                code = ICMP_UNREACH_SRCFAIL;
                   1164:                                goto bad;
                   1165:                        }
                   1166:                        ip->ip_dst = ipaddr.sin_addr;
1.20      mycroft  1167:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd      1168:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                   1169:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft  1170:                        /*
                   1171:                         * Let ip_intr's mcast routing check handle mcast pkts
                   1172:                         */
1.18      mycroft  1173:                        forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1       cgd      1174:                        break;
                   1175:
                   1176:                case IPOPT_RR:
1.114     itojun   1177:                        if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
                   1178:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                   1179:                                goto bad;
                   1180:                        }
1.1       cgd      1181:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                   1182:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                   1183:                                goto bad;
                   1184:                        }
                   1185:                        /*
                   1186:                         * If no space remains, ignore.
                   1187:                         */
                   1188:                        off--;                  /* 0 origin */
1.112     sommerfe 1189:                        if ((off + sizeof(struct in_addr)) > optlen)
1.1       cgd      1190:                                break;
                   1191:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                   1192:                            sizeof(ipaddr.sin_addr));
                   1193:                        /*
                   1194:                         * locate outgoing interface; if we're the destination,
                   1195:                         * use the incoming interface (should be same).
                   1196:                         */
1.96      thorpej  1197:                        if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))))
                   1198:                            == NULL &&
                   1199:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) {
1.1       cgd      1200:                                type = ICMP_UNREACH;
                   1201:                                code = ICMP_UNREACH_HOST;
                   1202:                                goto bad;
                   1203:                        }
1.20      mycroft  1204:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd      1205:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                   1206:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                   1207:                        break;
                   1208:
                   1209:                case IPOPT_TS:
                   1210:                        code = cp - (u_char *)ip;
                   1211:                        ipt = (struct ip_timestamp *)cp;
1.114     itojun   1212:                        if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
                   1213:                                code = (u_char *)&ipt->ipt_len - (u_char *)ip;
1.1       cgd      1214:                                goto bad;
1.114     itojun   1215:                        }
                   1216:                        if (ipt->ipt_ptr < 5) {
                   1217:                                code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
                   1218:                                goto bad;
                   1219:                        }
1.15      cgd      1220:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.114     itojun   1221:                                if (++ipt->ipt_oflw == 0) {
                   1222:                                        code = (u_char *)&ipt->ipt_ptr -
                   1223:                                            (u_char *)ip;
1.1       cgd      1224:                                        goto bad;
1.114     itojun   1225:                                }
1.1       cgd      1226:                                break;
                   1227:                        }
1.104     thorpej  1228:                        cp0 = (cp + ipt->ipt_ptr - 1);
1.1       cgd      1229:                        switch (ipt->ipt_flg) {
                   1230:
                   1231:                        case IPOPT_TS_TSONLY:
                   1232:                                break;
                   1233:
                   1234:                        case IPOPT_TS_TSANDADDR:
1.66      thorpej  1235:                                if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1.114     itojun   1236:                                    sizeof(struct in_addr) > ipt->ipt_len) {
                   1237:                                        code = (u_char *)&ipt->ipt_ptr -
                   1238:                                            (u_char *)ip;
1.1       cgd      1239:                                        goto bad;
1.114     itojun   1240:                                }
1.13      mycroft  1241:                                ipaddr.sin_addr = dst;
1.96      thorpej  1242:                                ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr),
                   1243:                                    m->m_pkthdr.rcvif));
1.13      mycroft  1244:                                if (ia == 0)
                   1245:                                        continue;
1.104     thorpej  1246:                                bcopy(&ia->ia_addr.sin_addr,
                   1247:                                    cp0, sizeof(struct in_addr));
1.1       cgd      1248:                                ipt->ipt_ptr += sizeof(struct in_addr);
                   1249:                                break;
                   1250:
                   1251:                        case IPOPT_TS_PRESPEC:
1.66      thorpej  1252:                                if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1.114     itojun   1253:                                    sizeof(struct in_addr) > ipt->ipt_len) {
                   1254:                                        code = (u_char *)&ipt->ipt_ptr -
                   1255:                                            (u_char *)ip;
1.1       cgd      1256:                                        goto bad;
1.114     itojun   1257:                                }
1.104     thorpej  1258:                                bcopy(cp0, &ipaddr.sin_addr,
1.1       cgd      1259:                                    sizeof(struct in_addr));
1.96      thorpej  1260:                                if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))
                   1261:                                    == NULL)
1.1       cgd      1262:                                        continue;
                   1263:                                ipt->ipt_ptr += sizeof(struct in_addr);
                   1264:                                break;
                   1265:
                   1266:                        default:
1.114     itojun   1267:                                /* XXX can't take &ipt->ipt_flg */
                   1268:                                code = (u_char *)&ipt->ipt_ptr -
                   1269:                                    (u_char *)ip + 1;
1.1       cgd      1270:                                goto bad;
                   1271:                        }
                   1272:                        ntime = iptime();
1.107     thorpej  1273:                        cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
                   1274:                        bcopy(cp0, (caddr_t)cp + ipt->ipt_ptr - 1,
1.1       cgd      1275:                            sizeof(n_time));
                   1276:                        ipt->ipt_ptr += sizeof(n_time);
                   1277:                }
                   1278:        }
                   1279:        if (forward) {
1.26      thorpej  1280:                if (ip_forwsrcrt == 0) {
                   1281:                        type = ICMP_UNREACH;
                   1282:                        code = ICMP_UNREACH_SRCFAIL;
                   1283:                        goto bad;
                   1284:                }
1.1       cgd      1285:                ip_forward(m, 1);
                   1286:                return (1);
1.13      mycroft  1287:        }
                   1288:        return (0);
1.1       cgd      1289: bad:
1.13      mycroft  1290:        icmp_error(m, type, code, 0, 0);
                   1291:        ipstat.ips_badoptions++;
1.1       cgd      1292:        return (1);
                   1293: }
                   1294:
                   1295: /*
                   1296:  * Given address of next destination (final or next hop),
                   1297:  * return internet address info of interface to be used to get there.
                   1298:  */
                   1299: struct in_ifaddr *
                   1300: ip_rtaddr(dst)
                   1301:         struct in_addr dst;
                   1302: {
1.109     augustss 1303:        struct sockaddr_in *sin;
1.1       cgd      1304:
1.19      mycroft  1305:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1306:
1.35      mycroft  1307:        if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) {
1.1       cgd      1308:                if (ipforward_rt.ro_rt) {
                   1309:                        RTFREE(ipforward_rt.ro_rt);
                   1310:                        ipforward_rt.ro_rt = 0;
                   1311:                }
                   1312:                sin->sin_family = AF_INET;
                   1313:                sin->sin_len = sizeof(*sin);
                   1314:                sin->sin_addr = dst;
                   1315:
                   1316:                rtalloc(&ipforward_rt);
                   1317:        }
                   1318:        if (ipforward_rt.ro_rt == 0)
                   1319:                return ((struct in_ifaddr *)0);
1.19      mycroft  1320:        return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1       cgd      1321: }
                   1322:
                   1323: /*
                   1324:  * Save incoming source route for use in replies,
                   1325:  * to be picked up later by ip_srcroute if the receiver is interested.
                   1326:  */
1.13      mycroft  1327: void
1.1       cgd      1328: save_rte(option, dst)
                   1329:        u_char *option;
                   1330:        struct in_addr dst;
                   1331: {
                   1332:        unsigned olen;
                   1333:
                   1334:        olen = option[IPOPT_OLEN];
                   1335: #ifdef DIAGNOSTIC
                   1336:        if (ipprintfs)
1.39      christos 1337:                printf("save_rte: olen %d\n", olen);
1.89      itojun   1338: #endif /* 0 */
1.1       cgd      1339:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                   1340:                return;
                   1341:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                   1342:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                   1343:        ip_srcrt.dst = dst;
                   1344: }
                   1345:
                   1346: /*
                   1347:  * Retrieve incoming source route for use in replies,
                   1348:  * in the same form used by setsockopt.
                   1349:  * The first hop is placed before the options, will be removed later.
                   1350:  */
                   1351: struct mbuf *
                   1352: ip_srcroute()
                   1353: {
1.109     augustss 1354:        struct in_addr *p, *q;
                   1355:        struct mbuf *m;
1.1       cgd      1356:
                   1357:        if (ip_nhops == 0)
                   1358:                return ((struct mbuf *)0);
                   1359:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                   1360:        if (m == 0)
                   1361:                return ((struct mbuf *)0);
                   1362:
1.13      mycroft  1363: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd      1364:
                   1365:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                   1366:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                   1367:            OPTSIZ;
                   1368: #ifdef DIAGNOSTIC
                   1369:        if (ipprintfs)
1.39      christos 1370:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
1.1       cgd      1371: #endif
                   1372:
                   1373:        /*
                   1374:         * First save first hop for return route
                   1375:         */
                   1376:        p = &ip_srcrt.route[ip_nhops - 1];
                   1377:        *(mtod(m, struct in_addr *)) = *p--;
                   1378: #ifdef DIAGNOSTIC
                   1379:        if (ipprintfs)
1.39      christos 1380:                printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1.1       cgd      1381: #endif
                   1382:
                   1383:        /*
                   1384:         * Copy option fields and padding (nop) to mbuf.
                   1385:         */
                   1386:        ip_srcrt.nop = IPOPT_NOP;
                   1387:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                   1388:        bcopy((caddr_t)&ip_srcrt.nop,
                   1389:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                   1390:        q = (struct in_addr *)(mtod(m, caddr_t) +
                   1391:            sizeof(struct in_addr) + OPTSIZ);
                   1392: #undef OPTSIZ
                   1393:        /*
                   1394:         * Record return path as an IP source route,
                   1395:         * reversing the path (pointers are now aligned).
                   1396:         */
                   1397:        while (p >= ip_srcrt.route) {
                   1398: #ifdef DIAGNOSTIC
                   1399:                if (ipprintfs)
1.39      christos 1400:                        printf(" %x", ntohl(q->s_addr));
1.1       cgd      1401: #endif
                   1402:                *q++ = *p--;
                   1403:        }
                   1404:        /*
                   1405:         * Last hop goes to final destination.
                   1406:         */
                   1407:        *q = ip_srcrt.dst;
                   1408: #ifdef DIAGNOSTIC
                   1409:        if (ipprintfs)
1.39      christos 1410:                printf(" %x\n", ntohl(q->s_addr));
1.1       cgd      1411: #endif
                   1412:        return (m);
                   1413: }
                   1414:
                   1415: /*
                   1416:  * Strip out IP options, at higher
                   1417:  * level protocol in the kernel.
                   1418:  * Second argument is buffer to which options
                   1419:  * will be moved, and return value is their length.
                   1420:  * XXX should be deleted; last arg currently ignored.
                   1421:  */
1.8       mycroft  1422: void
1.1       cgd      1423: ip_stripoptions(m, mopt)
1.109     augustss 1424:        struct mbuf *m;
1.1       cgd      1425:        struct mbuf *mopt;
                   1426: {
1.109     augustss 1427:        int i;
1.1       cgd      1428:        struct ip *ip = mtod(m, struct ip *);
1.109     augustss 1429:        caddr_t opts;
1.1       cgd      1430:        int olen;
                   1431:
1.79      mycroft  1432:        olen = (ip->ip_hl << 2) - sizeof (struct ip);
1.1       cgd      1433:        opts = (caddr_t)(ip + 1);
                   1434:        i = m->m_len - (sizeof (struct ip) + olen);
                   1435:        bcopy(opts  + olen, opts, (unsigned)i);
                   1436:        m->m_len -= olen;
                   1437:        if (m->m_flags & M_PKTHDR)
                   1438:                m->m_pkthdr.len -= olen;
1.79      mycroft  1439:        ip->ip_len -= olen;
                   1440:        ip->ip_hl = sizeof (struct ip) >> 2;
1.1       cgd      1441: }
                   1442:
1.23      mycroft  1443: int inetctlerrmap[PRC_NCMDS] = {
1.1       cgd      1444:        0,              0,              0,              0,
                   1445:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                   1446:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                   1447:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                   1448:        0,              0,              0,              0,
                   1449:        ENOPROTOOPT
                   1450: };
                   1451:
                   1452: /*
                   1453:  * Forward a packet.  If some error occurs return the sender
                   1454:  * an icmp packet.  Note we can't always generate a meaningful
                   1455:  * icmp message because icmp doesn't have a large enough repertoire
                   1456:  * of codes and types.
                   1457:  *
                   1458:  * If not forwarding, just drop the packet.  This could be confusing
                   1459:  * if ipforwarding was zero but some routing protocol was advancing
                   1460:  * us as a gateway to somewhere.  However, we must let the routing
                   1461:  * protocol deal with that.
                   1462:  *
                   1463:  * The srcrt parameter indicates whether the packet is being forwarded
                   1464:  * via a source route.
                   1465:  */
1.13      mycroft  1466: void
1.1       cgd      1467: ip_forward(m, srcrt)
                   1468:        struct mbuf *m;
                   1469:        int srcrt;
                   1470: {
1.109     augustss 1471:        struct ip *ip = mtod(m, struct ip *);
                   1472:        struct sockaddr_in *sin;
                   1473:        struct rtentry *rt;
1.28      christos 1474:        int error, type = 0, code = 0;
1.1       cgd      1475:        struct mbuf *mcopy;
1.13      mycroft  1476:        n_long dest;
                   1477:        struct ifnet *destifp;
1.89      itojun   1478: #ifdef IPSEC
                   1479:        struct ifnet dummyifp;
                   1480: #endif
1.135     thorpej  1481:
                   1482:        /*
                   1483:         * Clear any in-bound checksum flags for this packet.
                   1484:         */
                   1485:        m->m_pkthdr.csum_flags = 0;
1.1       cgd      1486:
1.13      mycroft  1487:        dest = 0;
1.1       cgd      1488: #ifdef DIAGNOSTIC
                   1489:        if (ipprintfs)
1.70      thorpej  1490:                printf("forward: src %2.2x dst %2.2x ttl %x\n",
                   1491:                    ntohl(ip->ip_src.s_addr),
                   1492:                    ntohl(ip->ip_dst.s_addr), ip->ip_ttl);
1.1       cgd      1493: #endif
1.93      sommerfe 1494:        if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1.1       cgd      1495:                ipstat.ips_cantforward++;
                   1496:                m_freem(m);
                   1497:                return;
                   1498:        }
                   1499:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1500:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1501:                return;
                   1502:        }
                   1503:        ip->ip_ttl -= IPTTLDEC;
                   1504:
1.19      mycroft  1505:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1506:        if ((rt = ipforward_rt.ro_rt) == 0 ||
1.35      mycroft  1507:            !in_hosteq(ip->ip_dst, sin->sin_addr)) {
1.1       cgd      1508:                if (ipforward_rt.ro_rt) {
                   1509:                        RTFREE(ipforward_rt.ro_rt);
                   1510:                        ipforward_rt.ro_rt = 0;
                   1511:                }
                   1512:                sin->sin_family = AF_INET;
1.35      mycroft  1513:                sin->sin_len = sizeof(struct sockaddr_in);
1.1       cgd      1514:                sin->sin_addr = ip->ip_dst;
                   1515:
                   1516:                rtalloc(&ipforward_rt);
                   1517:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1518:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1519:                        return;
                   1520:                }
                   1521:                rt = ipforward_rt.ro_rt;
                   1522:        }
                   1523:
                   1524:        /*
1.34      mycroft  1525:         * Save at most 68 bytes of the packet in case
1.1       cgd      1526:         * we need to generate an ICMP message to the src.
1.119     itojun   1527:         * Pullup to avoid sharing mbuf cluster between m and mcopy.
1.1       cgd      1528:         */
1.119     itojun   1529:        mcopy = m_copym(m, 0, imin((int)ip->ip_len, 68), M_DONTWAIT);
                   1530:        if (mcopy)
                   1531:                mcopy = m_pullup(mcopy, ip->ip_hl << 2);
1.1       cgd      1532:
                   1533:        /*
                   1534:         * If forwarding packet using same interface that it came in on,
                   1535:         * perhaps should send a redirect to sender to shortcut a hop.
                   1536:         * Only send redirect if source is sending directly to us,
                   1537:         * and if packet was not source routed (or has any options).
                   1538:         * Also, don't send redirect if forwarding using a default route
                   1539:         * or a route modified by a redirect.
                   1540:         */
                   1541:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1542:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1.35      mycroft  1543:            !in_nullhost(satosin(rt_key(rt))->sin_addr) &&
1.1       cgd      1544:            ipsendredirects && !srcrt) {
1.19      mycroft  1545:                if (rt->rt_ifa &&
                   1546:                    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
                   1547:                    ifatoia(rt->rt_ifa)->ia_subnet) {
1.77      thorpej  1548:                        if (rt->rt_flags & RTF_GATEWAY)
                   1549:                                dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
                   1550:                        else
                   1551:                                dest = ip->ip_dst.s_addr;
                   1552:                        /*
                   1553:                         * Router requirements says to only send host
                   1554:                         * redirects.
                   1555:                         */
                   1556:                        type = ICMP_REDIRECT;
                   1557:                        code = ICMP_REDIRECT_HOST;
1.1       cgd      1558: #ifdef DIAGNOSTIC
1.77      thorpej  1559:                        if (ipprintfs)
                   1560:                                printf("redirect (%d) to %x\n", code,
                   1561:                                    (u_int32_t)dest);
1.1       cgd      1562: #endif
                   1563:                }
                   1564:        }
                   1565:
1.89      itojun   1566: #ifdef IPSEC
1.134     lukem    1567:        /* Don't lookup socket in forwarding case */
1.127     itojun   1568:        (void)ipsec_setsocket(m, NULL);
1.103     itojun   1569: #endif
1.27      thorpej  1570:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
                   1571:            (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0);
1.1       cgd      1572:        if (error)
                   1573:                ipstat.ips_cantforward++;
                   1574:        else {
                   1575:                ipstat.ips_forward++;
                   1576:                if (type)
                   1577:                        ipstat.ips_redirectsent++;
                   1578:                else {
1.63      matt     1579:                        if (mcopy) {
                   1580: #ifdef GATEWAY
1.64      thorpej  1581:                                if (mcopy->m_flags & M_CANFASTFWD)
                   1582:                                        ipflow_create(&ipforward_rt, mcopy);
1.63      matt     1583: #endif
1.1       cgd      1584:                                m_freem(mcopy);
1.63      matt     1585:                        }
1.1       cgd      1586:                        return;
                   1587:                }
                   1588:        }
                   1589:        if (mcopy == NULL)
                   1590:                return;
1.13      mycroft  1591:        destifp = NULL;
                   1592:
1.1       cgd      1593:        switch (error) {
                   1594:
                   1595:        case 0:                         /* forwarded, but need redirect */
                   1596:                /* type, code set above */
                   1597:                break;
                   1598:
                   1599:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1600:        case EHOSTUNREACH:
                   1601:        case ENETDOWN:
                   1602:        case EHOSTDOWN:
                   1603:        default:
                   1604:                type = ICMP_UNREACH;
                   1605:                code = ICMP_UNREACH_HOST;
                   1606:                break;
                   1607:
                   1608:        case EMSGSIZE:
                   1609:                type = ICMP_UNREACH;
                   1610:                code = ICMP_UNREACH_NEEDFRAG;
1.89      itojun   1611: #ifndef IPSEC
1.13      mycroft  1612:                if (ipforward_rt.ro_rt)
                   1613:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.89      itojun   1614: #else
                   1615:                /*
                   1616:                 * If the packet is routed over IPsec tunnel, tell the
                   1617:                 * originator the tunnel MTU.
                   1618:                 *      tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
                   1619:                 * XXX quickhack!!!
                   1620:                 */
                   1621:                if (ipforward_rt.ro_rt) {
                   1622:                        struct secpolicy *sp;
                   1623:                        int ipsecerror;
1.95      itojun   1624:                        size_t ipsechdr;
1.89      itojun   1625:                        struct route *ro;
                   1626:
                   1627:                        sp = ipsec4_getpolicybyaddr(mcopy,
1.95      itojun   1628:                                                    IPSEC_DIR_OUTBOUND,
                   1629:                                                    IP_FORWARDING,
                   1630:                                                    &ipsecerror);
1.89      itojun   1631:
                   1632:                        if (sp == NULL)
                   1633:                                destifp = ipforward_rt.ro_rt->rt_ifp;
                   1634:                        else {
                   1635:                                /* count IPsec header size */
1.95      itojun   1636:                                ipsechdr = ipsec4_hdrsiz(mcopy,
                   1637:                                                         IPSEC_DIR_OUTBOUND,
                   1638:                                                         NULL);
1.89      itojun   1639:
                   1640:                                /*
                   1641:                                 * find the correct route for outer IPv4
                   1642:                                 * header, compute tunnel MTU.
                   1643:                                 *
                   1644:                                 * XXX BUG ALERT
                   1645:                                 * The "dummyifp" code relies upon the fact
                   1646:                                 * that icmp_error() touches only ifp->if_mtu.
                   1647:                                 */
                   1648:                                /*XXX*/
                   1649:                                destifp = NULL;
                   1650:                                if (sp->req != NULL
1.95      itojun   1651:                                 && sp->req->sav != NULL
                   1652:                                 && sp->req->sav->sah != NULL) {
                   1653:                                        ro = &sp->req->sav->sah->sa_route;
1.89      itojun   1654:                                        if (ro->ro_rt && ro->ro_rt->rt_ifp) {
                   1655:                                                dummyifp.if_mtu =
                   1656:                                                    ro->ro_rt->rt_ifp->if_mtu;
                   1657:                                                dummyifp.if_mtu -= ipsechdr;
                   1658:                                                destifp = &dummyifp;
                   1659:                                        }
                   1660:                                }
                   1661:
                   1662:                                key_freesp(sp);
                   1663:                        }
                   1664:                }
                   1665: #endif /*IPSEC*/
1.1       cgd      1666:                ipstat.ips_cantfrag++;
                   1667:                break;
                   1668:
                   1669:        case ENOBUFS:
                   1670:                type = ICMP_SOURCEQUENCH;
                   1671:                code = 0;
                   1672:                break;
                   1673:        }
1.13      mycroft  1674:        icmp_error(mcopy, type, code, dest, destifp);
1.44      thorpej  1675: }
                   1676:
                   1677: void
                   1678: ip_savecontrol(inp, mp, ip, m)
1.109     augustss 1679:        struct inpcb *inp;
                   1680:        struct mbuf **mp;
                   1681:        struct ip *ip;
                   1682:        struct mbuf *m;
1.44      thorpej  1683: {
                   1684:
                   1685:        if (inp->inp_socket->so_options & SO_TIMESTAMP) {
                   1686:                struct timeval tv;
                   1687:
                   1688:                microtime(&tv);
                   1689:                *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
                   1690:                    SCM_TIMESTAMP, SOL_SOCKET);
                   1691:                if (*mp)
                   1692:                        mp = &(*mp)->m_next;
                   1693:        }
                   1694:        if (inp->inp_flags & INP_RECVDSTADDR) {
                   1695:                *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
                   1696:                    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
                   1697:                if (*mp)
                   1698:                        mp = &(*mp)->m_next;
                   1699:        }
                   1700: #ifdef notyet
                   1701:        /*
                   1702:         * XXX
                   1703:         * Moving these out of udp_input() made them even more broken
                   1704:         * than they already were.
                   1705:         *      - fenner@parc.xerox.com
                   1706:         */
                   1707:        /* options were tossed already */
                   1708:        if (inp->inp_flags & INP_RECVOPTS) {
                   1709:                *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
                   1710:                    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
                   1711:                if (*mp)
                   1712:                        mp = &(*mp)->m_next;
                   1713:        }
                   1714:        /* ip_srcroute doesn't do what we want here, need to fix */
                   1715:        if (inp->inp_flags & INP_RECVRETOPTS) {
                   1716:                *mp = sbcreatecontrol((caddr_t) ip_srcroute(),
                   1717:                    sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
                   1718:                if (*mp)
                   1719:                        mp = &(*mp)->m_next;
                   1720:        }
                   1721: #endif
                   1722:        if (inp->inp_flags & INP_RECVIF) {
                   1723:                struct sockaddr_dl sdl;
                   1724:
                   1725:                sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]);
                   1726:                sdl.sdl_family = AF_LINK;
                   1727:                sdl.sdl_index = m->m_pkthdr.rcvif ?
                   1728:                    m->m_pkthdr.rcvif->if_index : 0;
                   1729:                sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0;
                   1730:                *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len,
                   1731:                    IP_RECVIF, IPPROTO_IP);
                   1732:                if (*mp)
                   1733:                        mp = &(*mp)->m_next;
                   1734:        }
1.13      mycroft  1735: }
                   1736:
                   1737: int
                   1738: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1739:        int *name;
                   1740:        u_int namelen;
                   1741:        void *oldp;
                   1742:        size_t *oldlenp;
                   1743:        void *newp;
                   1744:        size_t newlen;
                   1745: {
1.88      sommerfe 1746:        extern int subnetsarelocal, hostzeroisbroadcast;
1.52      thorpej  1747:
1.54      lukem    1748:        int error, old;
                   1749:
1.13      mycroft  1750:        /* All sysctl names at this level are terminal. */
                   1751:        if (namelen != 1)
                   1752:                return (ENOTDIR);
                   1753:
                   1754:        switch (name[0]) {
                   1755:        case IPCTL_FORWARDING:
                   1756:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
                   1757:        case IPCTL_SENDREDIRECTS:
                   1758:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1759:                        &ipsendredirects));
                   1760:        case IPCTL_DEFTTL:
                   1761:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
                   1762: #ifdef notyet
                   1763:        case IPCTL_DEFMTU:
                   1764:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
                   1765: #endif
1.26      thorpej  1766:        case IPCTL_FORWSRCRT:
1.47      cjs      1767:                /* Don't allow this to change in a secure environment.  */
1.26      thorpej  1768:                if (securelevel > 0)
1.46      cjs      1769:                        return (sysctl_rdint(oldp, oldlenp, newp,
                   1770:                            ip_forwsrcrt));
                   1771:                else
                   1772:                        return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1773:                            &ip_forwsrcrt));
1.27      thorpej  1774:        case IPCTL_DIRECTEDBCAST:
                   1775:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1776:                    &ip_directedbcast));
1.47      cjs      1777:        case IPCTL_ALLOWSRCRT:
                   1778:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1779:                    &ip_allowsrcrt));
1.52      thorpej  1780:        case IPCTL_SUBNETSARELOCAL:
                   1781:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1782:                    &subnetsarelocal));
1.53      kml      1783:        case IPCTL_MTUDISC:
1.60      kml      1784:                error = sysctl_int(oldp, oldlenp, newp, newlen,
                   1785:                    &ip_mtudisc);
                   1786:                if (ip_mtudisc != 0 && ip_mtudisc_timeout_q == NULL) {
                   1787:                        ip_mtudisc_timeout_q =
                   1788:                            rt_timer_queue_create(ip_mtudisc_timeout);
                   1789:                } else if (ip_mtudisc == 0 && ip_mtudisc_timeout_q != NULL) {
                   1790:                        rt_timer_queue_destroy(ip_mtudisc_timeout_q, TRUE);
                   1791:                        ip_mtudisc_timeout_q = NULL;
                   1792:                }
                   1793:                return error;
1.54      lukem    1794:        case IPCTL_ANONPORTMIN:
                   1795:                old = anonportmin;
                   1796:                error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmin);
1.118     itojun   1797:                if (anonportmin >= anonportmax || anonportmin < 0
                   1798:                    || anonportmin > 65535
1.54      lukem    1799: #ifndef IPNOPRIVPORTS
                   1800:                    || anonportmin < IPPORT_RESERVED
                   1801: #endif
                   1802:                    ) {
                   1803:                        anonportmin = old;
                   1804:                        return (EINVAL);
                   1805:                }
                   1806:                return (error);
                   1807:        case IPCTL_ANONPORTMAX:
                   1808:                old = anonportmax;
                   1809:                error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmax);
1.118     itojun   1810:                if (anonportmin >= anonportmax || anonportmax < 0
                   1811:                    || anonportmax > 65535
1.54      lukem    1812: #ifndef IPNOPRIVPORTS
                   1813:                    || anonportmax < IPPORT_RESERVED
                   1814: #endif
                   1815:                    ) {
                   1816:                        anonportmax = old;
                   1817:                        return (EINVAL);
                   1818:                }
1.60      kml      1819:                return (error);
                   1820:        case IPCTL_MTUDISCTIMEOUT:
                   1821:                error = sysctl_int(oldp, oldlenp, newp, newlen,
                   1822:                   &ip_mtudisc_timeout);
                   1823:                if (ip_mtudisc_timeout_q != NULL)
                   1824:                        rt_timer_queue_change(ip_mtudisc_timeout_q,
                   1825:                                              ip_mtudisc_timeout);
1.54      lukem    1826:                return (error);
1.65      matt     1827: #ifdef GATEWAY
                   1828:        case IPCTL_MAXFLOWS:
1.67      thorpej  1829:            {
                   1830:                int s;
                   1831:
1.65      matt     1832:                error = sysctl_int(oldp, oldlenp, newp, newlen,
                   1833:                   &ip_maxflows);
1.67      thorpej  1834:                s = splsoftnet();
1.65      matt     1835:                ipflow_reap(0);
1.67      thorpej  1836:                splx(s);
1.65      matt     1837:                return (error);
1.67      thorpej  1838:            }
1.89      itojun   1839: #endif
1.90      itojun   1840:        case IPCTL_HOSTZEROBROADCAST:
                   1841:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1842:                    &hostzeroisbroadcast));
1.89      itojun   1843: #if NGIF > 0
                   1844:        case IPCTL_GIF_TTL:
                   1845:                return(sysctl_int(oldp, oldlenp, newp, newlen,
1.90      itojun   1846:                                  &ip_gif_ttl));
1.117     tron     1847: #endif
                   1848:
                   1849: #ifndef IPNOPRIVPORTS
                   1850:        case IPCTL_LOWPORTMIN:
                   1851:                old = lowportmin;
                   1852:                error = sysctl_int(oldp, oldlenp, newp, newlen, &lowportmin);
                   1853:                if (lowportmin >= lowportmax
                   1854:                    || lowportmin > IPPORT_RESERVEDMAX
                   1855:                    || lowportmin < IPPORT_RESERVEDMIN
                   1856:                    ) {
                   1857:                        lowportmin = old;
                   1858:                        return (EINVAL);
                   1859:                }
                   1860:                return (error);
                   1861:        case IPCTL_LOWPORTMAX:
                   1862:                old = lowportmax;
                   1863:                error = sysctl_int(oldp, oldlenp, newp, newlen, &lowportmax);
                   1864:                if (lowportmin >= lowportmax
                   1865:                    || lowportmax > IPPORT_RESERVEDMAX
                   1866:                    || lowportmax < IPPORT_RESERVEDMIN
                   1867:                    ) {
                   1868:                        lowportmax = old;
                   1869:                        return (EINVAL);
                   1870:                }
                   1871:                return (error);
1.65      matt     1872: #endif
1.131     itojun   1873:
                   1874:        case IPCTL_MAXFRAGPACKETS:
                   1875:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1876:                    &ip_maxfragpackets));
1.88      sommerfe 1877:
1.13      mycroft  1878:        default:
                   1879:                return (EOPNOTSUPP);
                   1880:        }
                   1881:        /* NOTREACHED */
1.1       cgd      1882: }

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