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Annotation of src/sys/netinet/ip_input.c, Revision 1.13

1.1       cgd         1: /*
1.13    ! mycroft     2:  * Copyright (c) 1982, 1986, 1988, 1993
        !             3:  *     The Regents of the University of California.  All rights reserved.
1.1       cgd         4:  *
                      5:  * Redistribution and use in source and binary forms, with or without
                      6:  * modification, are permitted provided that the following conditions
                      7:  * are met:
                      8:  * 1. Redistributions of source code must retain the above copyright
                      9:  *    notice, this list of conditions and the following disclaimer.
                     10:  * 2. Redistributions in binary form must reproduce the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer in the
                     12:  *    documentation and/or other materials provided with the distribution.
                     13:  * 3. All advertising materials mentioning features or use of this software
                     14:  *    must display the following acknowledgement:
                     15:  *     This product includes software developed by the University of
                     16:  *     California, Berkeley and its contributors.
                     17:  * 4. Neither the name of the University nor the names of its contributors
                     18:  *    may be used to endorse or promote products derived from this software
                     19:  *    without specific prior written permission.
                     20:  *
                     21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     31:  * SUCH DAMAGE.
                     32:  *
1.13    ! mycroft    33:  *     from: @(#)ip_input.c    8.2 (Berkeley) 1/4/94
        !            34:  *     $Id: $
1.1       cgd        35:  */
                     36:
1.5       mycroft    37: #include <sys/param.h>
                     38: #include <sys/systm.h>
                     39: #include <sys/malloc.h>
                     40: #include <sys/mbuf.h>
                     41: #include <sys/domain.h>
                     42: #include <sys/protosw.h>
                     43: #include <sys/socket.h>
                     44: #include <sys/errno.h>
                     45: #include <sys/time.h>
                     46: #include <sys/kernel.h>
1.1       cgd        47:
1.5       mycroft    48: #include <net/if.h>
                     49: #include <net/route.h>
1.1       cgd        50:
1.5       mycroft    51: #include <netinet/in.h>
                     52: #include <netinet/in_systm.h>
                     53: #include <netinet/ip.h>
                     54: #include <netinet/in_pcb.h>
                     55: #include <netinet/in_var.h>
                     56: #include <netinet/ip_var.h>
                     57: #include <netinet/ip_icmp.h>
1.1       cgd        58:
                     59: #ifndef        IPFORWARDING
                     60: #ifdef GATEWAY
                     61: #define        IPFORWARDING    1       /* forward IP packets not for us */
                     62: #else /* GATEWAY */
                     63: #define        IPFORWARDING    0       /* don't forward IP packets not for us */
                     64: #endif /* GATEWAY */
                     65: #endif /* IPFORWARDING */
                     66: #ifndef        IPSENDREDIRECTS
                     67: #define        IPSENDREDIRECTS 1
                     68: #endif
                     69: int    ipforwarding = IPFORWARDING;
                     70: int    ipsendredirects = IPSENDREDIRECTS;
1.13    ! mycroft    71: int    ip_defttl = IPDEFTTL;
1.1       cgd        72: #ifdef DIAGNOSTIC
                     73: int    ipprintfs = 0;
                     74: #endif
                     75:
                     76: extern struct domain inetdomain;
                     77: extern struct protosw inetsw[];
                     78: u_char ip_protox[IPPROTO_MAX];
                     79: int    ipqmaxlen = IFQ_MAXLEN;
                     80: struct in_ifaddr *in_ifaddr;                   /* first inet address */
1.13    ! mycroft    81: struct ifqueue ipintrq;
1.1       cgd        82:
                     83: /*
                     84:  * We need to save the IP options in case a protocol wants to respond
                     85:  * to an incoming packet over the same route if the packet got here
                     86:  * using IP source routing.  This allows connection establishment and
                     87:  * maintenance when the remote end is on a network that is not known
                     88:  * to us.
                     89:  */
                     90: int    ip_nhops = 0;
                     91: static struct ip_srcrt {
                     92:        struct  in_addr dst;                    /* final destination */
                     93:        char    nop;                            /* one NOP to align */
                     94:        char    srcopt[IPOPT_OFFSET + 1];       /* OPTVAL, OLEN and OFFSET */
                     95:        struct  in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
                     96: } ip_srcrt;
                     97:
                     98: #ifdef GATEWAY
                     99: extern int if_index;
                    100: u_long *ip_ifmatrix;
                    101: #endif
                    102:
1.13    ! mycroft   103: static void save_rte __P((u_char *, struct in_addr));
1.1       cgd       104: /*
                    105:  * IP initialization: fill in IP protocol switch table.
                    106:  * All protocols not implemented in kernel go to raw IP protocol handler.
                    107:  */
1.8       mycroft   108: void
1.1       cgd       109: ip_init()
                    110: {
                    111:        register struct protosw *pr;
                    112:        register int i;
                    113:
                    114:        pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
                    115:        if (pr == 0)
                    116:                panic("ip_init");
                    117:        for (i = 0; i < IPPROTO_MAX; i++)
                    118:                ip_protox[i] = pr - inetsw;
                    119:        for (pr = inetdomain.dom_protosw;
                    120:            pr < inetdomain.dom_protoswNPROTOSW; pr++)
                    121:                if (pr->pr_domain->dom_family == PF_INET &&
                    122:                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
                    123:                        ip_protox[pr->pr_protocol] = pr - inetsw;
                    124:        ipq.next = ipq.prev = &ipq;
                    125:        ip_id = time.tv_sec & 0xffff;
                    126:        ipintrq.ifq_maxlen = ipqmaxlen;
                    127: #ifdef GATEWAY
                    128:        i = (if_index + 1) * (if_index + 1) * sizeof (u_long);
1.13    ! mycroft   129:        ip_ifmatrix = (u_long *) malloc(i, M_RTABLE, M_WAITOK);
        !           130:        bzero((char *)ip_ifmatrix, i);
1.1       cgd       131: #endif
                    132: }
                    133:
                    134: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    135: struct route ipforward_rt;
                    136:
                    137: /*
                    138:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    139:  * try to reassemble.  Process options.  Pass to next level.
                    140:  */
1.8       mycroft   141: void
1.1       cgd       142: ipintr()
                    143: {
                    144:        register struct ip *ip;
                    145:        register struct mbuf *m;
                    146:        register struct ipq *fp;
                    147:        register struct in_ifaddr *ia;
                    148:        int hlen, s;
                    149:
                    150: next:
                    151:        /*
                    152:         * Get next datagram off input queue and get IP header
                    153:         * in first mbuf.
                    154:         */
                    155:        s = splimp();
                    156:        IF_DEQUEUE(&ipintrq, m);
                    157:        splx(s);
1.13    ! mycroft   158:        if (m == 0)
1.1       cgd       159:                return;
                    160: #ifdef DIAGNOSTIC
                    161:        if ((m->m_flags & M_PKTHDR) == 0)
                    162:                panic("ipintr no HDR");
                    163: #endif
                    164:        /*
                    165:         * If no IP addresses have been set yet but the interfaces
                    166:         * are receiving, can't do anything with incoming packets yet.
                    167:         */
                    168:        if (in_ifaddr == NULL)
                    169:                goto bad;
                    170:        ipstat.ips_total++;
                    171:        if (m->m_len < sizeof (struct ip) &&
                    172:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    173:                ipstat.ips_toosmall++;
                    174:                goto next;
                    175:        }
                    176:        ip = mtod(m, struct ip *);
1.13    ! mycroft   177:        if (ip->ip_v != IPVERSION) {
        !           178:                ipstat.ips_badvers++;
        !           179:                goto bad;
        !           180:        }
1.1       cgd       181:        hlen = ip->ip_hl << 2;
                    182:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    183:                ipstat.ips_badhlen++;
                    184:                goto bad;
                    185:        }
                    186:        if (hlen > m->m_len) {
                    187:                if ((m = m_pullup(m, hlen)) == 0) {
                    188:                        ipstat.ips_badhlen++;
                    189:                        goto next;
                    190:                }
                    191:                ip = mtod(m, struct ip *);
                    192:        }
                    193:        if (ip->ip_sum = in_cksum(m, hlen)) {
                    194:                ipstat.ips_badsum++;
                    195:                goto bad;
                    196:        }
                    197:
                    198:        /*
                    199:         * Convert fields to host representation.
                    200:         */
                    201:        NTOHS(ip->ip_len);
                    202:        if (ip->ip_len < hlen) {
                    203:                ipstat.ips_badlen++;
                    204:                goto bad;
                    205:        }
                    206:        NTOHS(ip->ip_id);
                    207:        NTOHS(ip->ip_off);
                    208:
                    209:        /*
                    210:         * Check that the amount of data in the buffers
                    211:         * is as at least much as the IP header would have us expect.
                    212:         * Trim mbufs if longer than we expect.
                    213:         * Drop packet if shorter than we expect.
                    214:         */
                    215:        if (m->m_pkthdr.len < ip->ip_len) {
                    216:                ipstat.ips_tooshort++;
                    217:                goto bad;
                    218:        }
                    219:        if (m->m_pkthdr.len > ip->ip_len) {
                    220:                if (m->m_len == m->m_pkthdr.len) {
                    221:                        m->m_len = ip->ip_len;
                    222:                        m->m_pkthdr.len = ip->ip_len;
                    223:                } else
                    224:                        m_adj(m, ip->ip_len - m->m_pkthdr.len);
                    225:        }
                    226:
                    227:        /*
                    228:         * Process options and, if not destined for us,
                    229:         * ship it on.  ip_dooptions returns 1 when an
                    230:         * error was detected (causing an icmp message
                    231:         * to be sent and the original packet to be freed).
                    232:         */
                    233:        ip_nhops = 0;           /* for source routed packets */
                    234:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    235:                goto next;
                    236:
                    237:        /*
                    238:         * Check our list of addresses, to see if the packet is for us.
                    239:         */
                    240:        for (ia = in_ifaddr; ia; ia = ia->ia_next) {
                    241: #define        satosin(sa)     ((struct sockaddr_in *)(sa))
                    242:
                    243:                if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr)
                    244:                        goto ours;
                    245:                if (
                    246: #ifdef DIRECTED_BROADCAST
                    247:                    ia->ia_ifp == m->m_pkthdr.rcvif &&
                    248: #endif
                    249:                    (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
                    250:                        u_long t;
                    251:
                    252:                        if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
                    253:                            ip->ip_dst.s_addr)
                    254:                                goto ours;
                    255:                        if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr)
                    256:                                goto ours;
                    257:                        /*
                    258:                         * Look for all-0's host part (old broadcast addr),
                    259:                         * either for subnet or net.
                    260:                         */
                    261:                        t = ntohl(ip->ip_dst.s_addr);
                    262:                        if (t == ia->ia_subnet)
                    263:                                goto ours;
                    264:                        if (t == ia->ia_net)
                    265:                                goto ours;
                    266:                }
                    267:        }
1.4       hpeyerl   268:        if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
                    269:                struct in_multi *inm;
                    270: #ifdef MROUTING
                    271:                extern struct socket *ip_mrouter;
1.10      brezak    272:
                    273:                if (m->m_flags & M_EXT) {
                    274:                        if ((m = m_pullup(m, hlen)) == 0) {
                    275:                                ipstat.ips_toosmall++;
                    276:                                goto next;
                    277:                        }
                    278:                        ip = mtod(m, struct ip *);
                    279:                }
1.4       hpeyerl   280:
                    281:                if (ip_mrouter) {
                    282:                        /*
                    283:                         * If we are acting as a multicast router, all
                    284:                         * incoming multicast packets are passed to the
                    285:                         * kernel-level multicast forwarding function.
                    286:                         * The packet is returned (relatively) intact; if
                    287:                         * ip_mforward() returns a non-zero value, the packet
                    288:                         * must be discarded, else it may be accepted below.
                    289:                         *
                    290:                         * (The IP ident field is put in the same byte order
                    291:                         * as expected when ip_mforward() is called from
                    292:                         * ip_output().)
                    293:                         */
                    294:                        ip->ip_id = htons(ip->ip_id);
1.13    ! mycroft   295:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
        !           296:                                ipstat.ips_cantforward++;
1.4       hpeyerl   297:                                m_freem(m);
                    298:                                goto next;
                    299:                        }
                    300:                        ip->ip_id = ntohs(ip->ip_id);
                    301:
                    302:                        /*
                    303:                         * The process-level routing demon needs to receive
                    304:                         * all multicast IGMP packets, whether or not this
                    305:                         * host belongs to their destination groups.
                    306:                         */
                    307:                        if (ip->ip_p == IPPROTO_IGMP)
                    308:                                goto ours;
1.13    ! mycroft   309:                        ipstat.ips_forward++;
1.4       hpeyerl   310:                }
                    311: #endif
                    312:                /*
                    313:                 * See if we belong to the destination multicast group on the
                    314:                 * arrival interface.
                    315:                 */
                    316:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    317:                if (inm == NULL) {
1.13    ! mycroft   318:                        ipstat.ips_cantforward++;
1.4       hpeyerl   319:                        m_freem(m);
                    320:                        goto next;
                    321:                }
                    322:                goto ours;
                    323:        }
1.1       cgd       324:        if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
                    325:                goto ours;
                    326:        if (ip->ip_dst.s_addr == INADDR_ANY)
                    327:                goto ours;
                    328:
                    329:        /*
                    330:         * Not for us; forward if possible and desirable.
                    331:         */
                    332:        if (ipforwarding == 0) {
                    333:                ipstat.ips_cantforward++;
                    334:                m_freem(m);
                    335:        } else
                    336:                ip_forward(m, 0);
                    337:        goto next;
                    338:
                    339: ours:
                    340:        /*
                    341:         * If offset or IP_MF are set, must reassemble.
                    342:         * Otherwise, nothing need be done.
                    343:         * (We could look in the reassembly queue to see
                    344:         * if the packet was previously fragmented,
                    345:         * but it's not worth the time; just let them time out.)
                    346:         */
                    347:        if (ip->ip_off &~ IP_DF) {
                    348:                if (m->m_flags & M_EXT) {               /* XXX */
                    349:                        if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
                    350:                                ipstat.ips_toosmall++;
                    351:                                goto next;
                    352:                        }
                    353:                        ip = mtod(m, struct ip *);
                    354:                }
                    355:                /*
                    356:                 * Look for queue of fragments
                    357:                 * of this datagram.
                    358:                 */
                    359:                for (fp = ipq.next; fp != &ipq; fp = fp->next)
                    360:                        if (ip->ip_id == fp->ipq_id &&
                    361:                            ip->ip_src.s_addr == fp->ipq_src.s_addr &&
                    362:                            ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
                    363:                            ip->ip_p == fp->ipq_p)
                    364:                                goto found;
                    365:                fp = 0;
                    366: found:
                    367:
                    368:                /*
                    369:                 * Adjust ip_len to not reflect header,
                    370:                 * set ip_mff if more fragments are expected,
                    371:                 * convert offset of this to bytes.
                    372:                 */
                    373:                ip->ip_len -= hlen;
1.13    ! mycroft   374:                ((struct ipasfrag *)ip)->ipf_mff &= ~1;
1.1       cgd       375:                if (ip->ip_off & IP_MF)
1.13    ! mycroft   376:                        ((struct ipasfrag *)ip)->ipf_mff |= 1;
1.1       cgd       377:                ip->ip_off <<= 3;
                    378:
                    379:                /*
                    380:                 * If datagram marked as having more fragments
                    381:                 * or if this is not the first fragment,
                    382:                 * attempt reassembly; if it succeeds, proceed.
                    383:                 */
1.13    ! mycroft   384:                if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) {
1.1       cgd       385:                        ipstat.ips_fragments++;
                    386:                        ip = ip_reass((struct ipasfrag *)ip, fp);
                    387:                        if (ip == 0)
                    388:                                goto next;
1.13    ! mycroft   389:                        ipstat.ips_reassembled++;
1.1       cgd       390:                        m = dtom(ip);
                    391:                } else
                    392:                        if (fp)
                    393:                                ip_freef(fp);
                    394:        } else
                    395:                ip->ip_len -= hlen;
                    396:
                    397:        /*
                    398:         * Switch out to protocol's input routine.
                    399:         */
                    400:        ipstat.ips_delivered++;
                    401:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    402:        goto next;
                    403: bad:
                    404:        m_freem(m);
                    405:        goto next;
                    406: }
                    407:
                    408: /*
                    409:  * Take incoming datagram fragment and try to
                    410:  * reassemble it into whole datagram.  If a chain for
                    411:  * reassembly of this datagram already exists, then it
                    412:  * is given as fp; otherwise have to make a chain.
                    413:  */
                    414: struct ip *
                    415: ip_reass(ip, fp)
                    416:        register struct ipasfrag *ip;
                    417:        register struct ipq *fp;
                    418: {
                    419:        register struct mbuf *m = dtom(ip);
                    420:        register struct ipasfrag *q;
                    421:        struct mbuf *t;
                    422:        int hlen = ip->ip_hl << 2;
                    423:        int i, next;
                    424:
                    425:        /*
                    426:         * Presence of header sizes in mbufs
                    427:         * would confuse code below.
                    428:         */
                    429:        m->m_data += hlen;
                    430:        m->m_len -= hlen;
                    431:
                    432:        /*
                    433:         * If first fragment to arrive, create a reassembly queue.
                    434:         */
                    435:        if (fp == 0) {
                    436:                if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
                    437:                        goto dropfrag;
                    438:                fp = mtod(t, struct ipq *);
                    439:                insque(fp, &ipq);
                    440:                fp->ipq_ttl = IPFRAGTTL;
                    441:                fp->ipq_p = ip->ip_p;
                    442:                fp->ipq_id = ip->ip_id;
                    443:                fp->ipq_next = fp->ipq_prev = (struct ipasfrag *)fp;
                    444:                fp->ipq_src = ((struct ip *)ip)->ip_src;
                    445:                fp->ipq_dst = ((struct ip *)ip)->ip_dst;
                    446:                q = (struct ipasfrag *)fp;
                    447:                goto insert;
                    448:        }
                    449:
                    450:        /*
                    451:         * Find a segment which begins after this one does.
                    452:         */
                    453:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next)
                    454:                if (q->ip_off > ip->ip_off)
                    455:                        break;
                    456:
                    457:        /*
                    458:         * If there is a preceding segment, it may provide some of
                    459:         * our data already.  If so, drop the data from the incoming
                    460:         * segment.  If it provides all of our data, drop us.
                    461:         */
                    462:        if (q->ipf_prev != (struct ipasfrag *)fp) {
                    463:                i = q->ipf_prev->ip_off + q->ipf_prev->ip_len - ip->ip_off;
                    464:                if (i > 0) {
                    465:                        if (i >= ip->ip_len)
                    466:                                goto dropfrag;
                    467:                        m_adj(dtom(ip), i);
                    468:                        ip->ip_off += i;
                    469:                        ip->ip_len -= i;
                    470:                }
                    471:        }
                    472:
                    473:        /*
                    474:         * While we overlap succeeding segments trim them or,
                    475:         * if they are completely covered, dequeue them.
                    476:         */
                    477:        while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) {
                    478:                i = (ip->ip_off + ip->ip_len) - q->ip_off;
                    479:                if (i < q->ip_len) {
                    480:                        q->ip_len -= i;
                    481:                        q->ip_off += i;
                    482:                        m_adj(dtom(q), i);
                    483:                        break;
                    484:                }
                    485:                q = q->ipf_next;
                    486:                m_freem(dtom(q->ipf_prev));
                    487:                ip_deq(q->ipf_prev);
                    488:        }
                    489:
                    490: insert:
                    491:        /*
                    492:         * Stick new segment in its place;
                    493:         * check for complete reassembly.
                    494:         */
                    495:        ip_enq(ip, q->ipf_prev);
                    496:        next = 0;
                    497:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) {
                    498:                if (q->ip_off != next)
                    499:                        return (0);
                    500:                next += q->ip_len;
                    501:        }
1.13    ! mycroft   502:        if (q->ipf_prev->ipf_mff & 1)
1.1       cgd       503:                return (0);
                    504:
                    505:        /*
                    506:         * Reassembly is complete; concatenate fragments.
                    507:         */
                    508:        q = fp->ipq_next;
                    509:        m = dtom(q);
                    510:        t = m->m_next;
                    511:        m->m_next = 0;
                    512:        m_cat(m, t);
                    513:        q = q->ipf_next;
                    514:        while (q != (struct ipasfrag *)fp) {
                    515:                t = dtom(q);
                    516:                q = q->ipf_next;
                    517:                m_cat(m, t);
                    518:        }
                    519:
                    520:        /*
                    521:         * Create header for new ip packet by
                    522:         * modifying header of first packet;
                    523:         * dequeue and discard fragment reassembly header.
                    524:         * Make header visible.
                    525:         */
                    526:        ip = fp->ipq_next;
                    527:        ip->ip_len = next;
1.13    ! mycroft   528:        ip->ipf_mff &= ~1;
1.1       cgd       529:        ((struct ip *)ip)->ip_src = fp->ipq_src;
                    530:        ((struct ip *)ip)->ip_dst = fp->ipq_dst;
                    531:        remque(fp);
                    532:        (void) m_free(dtom(fp));
                    533:        m = dtom(ip);
                    534:        m->m_len += (ip->ip_hl << 2);
                    535:        m->m_data -= (ip->ip_hl << 2);
                    536:        /* some debugging cruft by sklower, below, will go away soon */
                    537:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
                    538:                register int plen = 0;
                    539:                for (t = m; m; m = m->m_next)
                    540:                        plen += m->m_len;
                    541:                t->m_pkthdr.len = plen;
                    542:        }
                    543:        return ((struct ip *)ip);
                    544:
                    545: dropfrag:
                    546:        ipstat.ips_fragdropped++;
                    547:        m_freem(m);
                    548:        return (0);
                    549: }
                    550:
                    551: /*
                    552:  * Free a fragment reassembly header and all
                    553:  * associated datagrams.
                    554:  */
1.8       mycroft   555: void
1.1       cgd       556: ip_freef(fp)
                    557:        struct ipq *fp;
                    558: {
                    559:        register struct ipasfrag *q, *p;
                    560:
                    561:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = p) {
                    562:                p = q->ipf_next;
                    563:                ip_deq(q);
                    564:                m_freem(dtom(q));
                    565:        }
                    566:        remque(fp);
                    567:        (void) m_free(dtom(fp));
                    568: }
                    569:
                    570: /*
                    571:  * Put an ip fragment on a reassembly chain.
                    572:  * Like insque, but pointers in middle of structure.
                    573:  */
1.8       mycroft   574: void
1.1       cgd       575: ip_enq(p, prev)
                    576:        register struct ipasfrag *p, *prev;
                    577: {
                    578:
                    579:        p->ipf_prev = prev;
                    580:        p->ipf_next = prev->ipf_next;
                    581:        prev->ipf_next->ipf_prev = p;
                    582:        prev->ipf_next = p;
                    583: }
                    584:
                    585: /*
                    586:  * To ip_enq as remque is to insque.
                    587:  */
1.8       mycroft   588: void
1.1       cgd       589: ip_deq(p)
                    590:        register struct ipasfrag *p;
                    591: {
                    592:
                    593:        p->ipf_prev->ipf_next = p->ipf_next;
                    594:        p->ipf_next->ipf_prev = p->ipf_prev;
                    595: }
                    596:
                    597: /*
                    598:  * IP timer processing;
                    599:  * if a timer expires on a reassembly
                    600:  * queue, discard it.
                    601:  */
1.8       mycroft   602: void
1.1       cgd       603: ip_slowtimo()
                    604: {
                    605:        register struct ipq *fp;
                    606:        int s = splnet();
                    607:
                    608:        fp = ipq.next;
                    609:        if (fp == 0) {
                    610:                splx(s);
                    611:                return;
                    612:        }
                    613:        while (fp != &ipq) {
                    614:                --fp->ipq_ttl;
                    615:                fp = fp->next;
                    616:                if (fp->prev->ipq_ttl == 0) {
                    617:                        ipstat.ips_fragtimeout++;
                    618:                        ip_freef(fp->prev);
                    619:                }
                    620:        }
                    621:        splx(s);
                    622: }
                    623:
                    624: /*
                    625:  * Drain off all datagram fragments.
                    626:  */
1.8       mycroft   627: void
1.1       cgd       628: ip_drain()
                    629: {
                    630:
                    631:        while (ipq.next != &ipq) {
                    632:                ipstat.ips_fragdropped++;
                    633:                ip_freef(ipq.next);
                    634:        }
                    635: }
                    636:
                    637: /*
                    638:  * Do option processing on a datagram,
                    639:  * possibly discarding it if bad options are encountered,
                    640:  * or forwarding it if source-routed.
                    641:  * Returns 1 if packet has been forwarded/freed,
                    642:  * 0 if the packet should be processed further.
                    643:  */
1.8       mycroft   644: int
1.1       cgd       645: ip_dooptions(m)
                    646:        struct mbuf *m;
                    647: {
                    648:        register struct ip *ip = mtod(m, struct ip *);
                    649:        register u_char *cp;
                    650:        register struct ip_timestamp *ipt;
                    651:        register struct in_ifaddr *ia;
                    652:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13    ! mycroft   653:        struct in_addr *sin, dst;
1.1       cgd       654:        n_time ntime;
                    655:
1.13    ! mycroft   656:        dst = ip->ip_dst;
1.1       cgd       657:        cp = (u_char *)(ip + 1);
                    658:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    659:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    660:                opt = cp[IPOPT_OPTVAL];
                    661:                if (opt == IPOPT_EOL)
                    662:                        break;
                    663:                if (opt == IPOPT_NOP)
                    664:                        optlen = 1;
                    665:                else {
                    666:                        optlen = cp[IPOPT_OLEN];
                    667:                        if (optlen <= 0 || optlen > cnt) {
                    668:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    669:                                goto bad;
                    670:                        }
                    671:                }
                    672:                switch (opt) {
                    673:
                    674:                default:
                    675:                        break;
                    676:
                    677:                /*
                    678:                 * Source routing with record.
                    679:                 * Find interface with current destination address.
                    680:                 * If none on this machine then drop if strictly routed,
                    681:                 * or do nothing if loosely routed.
                    682:                 * Record interface address and bring up next address
                    683:                 * component.  If strictly routed make sure next
                    684:                 * address is on directly accessible net.
                    685:                 */
                    686:                case IPOPT_LSRR:
                    687:                case IPOPT_SSRR:
                    688:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    689:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    690:                                goto bad;
                    691:                        }
                    692:                        ipaddr.sin_addr = ip->ip_dst;
                    693:                        ia = (struct in_ifaddr *)
                    694:                                ifa_ifwithaddr((struct sockaddr *)&ipaddr);
                    695:                        if (ia == 0) {
                    696:                                if (opt == IPOPT_SSRR) {
                    697:                                        type = ICMP_UNREACH;
                    698:                                        code = ICMP_UNREACH_SRCFAIL;
                    699:                                        goto bad;
                    700:                                }
                    701:                                /*
                    702:                                 * Loose routing, and not at next destination
                    703:                                 * yet; nothing to do except forward.
                    704:                                 */
                    705:                                break;
                    706:                        }
                    707:                        off--;                  /* 0 origin */
                    708:                        if (off > optlen - sizeof(struct in_addr)) {
                    709:                                /*
                    710:                                 * End of source route.  Should be for us.
                    711:                                 */
                    712:                                save_rte(cp, ip->ip_src);
                    713:                                break;
                    714:                        }
                    715:                        /*
                    716:                         * locate outgoing interface
                    717:                         */
                    718:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    719:                            sizeof(ipaddr.sin_addr));
                    720:                        if (opt == IPOPT_SSRR) {
                    721: #define        INA     struct in_ifaddr *
                    722: #define        SA      struct sockaddr *
                    723:                            if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
1.13    ! mycroft   724:                                ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1.1       cgd       725:                        } else
                    726:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    727:                        if (ia == 0) {
                    728:                                type = ICMP_UNREACH;
                    729:                                code = ICMP_UNREACH_SRCFAIL;
                    730:                                goto bad;
                    731:                        }
                    732:                        ip->ip_dst = ipaddr.sin_addr;
                    733:                        bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
                    734:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    735:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13    ! mycroft   736:                        /*
        !           737:                         * Let ip_intr's mcast routing check handle mcast pkts
        !           738:                         */
        !           739:                        forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
1.1       cgd       740:                        break;
                    741:
                    742:                case IPOPT_RR:
                    743:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    744:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    745:                                goto bad;
                    746:                        }
                    747:                        /*
                    748:                         * If no space remains, ignore.
                    749:                         */
                    750:                        off--;                  /* 0 origin */
                    751:                        if (off > optlen - sizeof(struct in_addr))
                    752:                                break;
                    753:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    754:                            sizeof(ipaddr.sin_addr));
                    755:                        /*
                    756:                         * locate outgoing interface; if we're the destination,
                    757:                         * use the incoming interface (should be same).
                    758:                         */
                    759:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    760:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    761:                                type = ICMP_UNREACH;
                    762:                                code = ICMP_UNREACH_HOST;
                    763:                                goto bad;
                    764:                        }
                    765:                        bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
                    766:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    767:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    768:                        break;
                    769:
                    770:                case IPOPT_TS:
                    771:                        code = cp - (u_char *)ip;
                    772:                        ipt = (struct ip_timestamp *)cp;
                    773:                        if (ipt->ipt_len < 5)
                    774:                                goto bad;
                    775:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (long)) {
                    776:                                if (++ipt->ipt_oflw == 0)
                    777:                                        goto bad;
                    778:                                break;
                    779:                        }
                    780:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    781:                        switch (ipt->ipt_flg) {
                    782:
                    783:                        case IPOPT_TS_TSONLY:
                    784:                                break;
                    785:
                    786:                        case IPOPT_TS_TSANDADDR:
                    787:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    788:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    789:                                        goto bad;
1.13    ! mycroft   790:                                ipaddr.sin_addr = dst;
        !           791:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
        !           792:                                                            m->m_pkthdr.rcvif);
        !           793:                                if (ia == 0)
        !           794:                                        continue;
1.1       cgd       795:                                bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
                    796:                                    (caddr_t)sin, sizeof(struct in_addr));
                    797:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    798:                                break;
                    799:
                    800:                        case IPOPT_TS_PRESPEC:
                    801:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    802:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    803:                                        goto bad;
                    804:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    805:                                    sizeof(struct in_addr));
                    806:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    807:                                        continue;
                    808:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    809:                                break;
                    810:
                    811:                        default:
                    812:                                goto bad;
                    813:                        }
                    814:                        ntime = iptime();
                    815:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    816:                            sizeof(n_time));
                    817:                        ipt->ipt_ptr += sizeof(n_time);
                    818:                }
                    819:        }
                    820:        if (forward) {
                    821:                ip_forward(m, 1);
                    822:                return (1);
1.13    ! mycroft   823:        }
        !           824:        return (0);
1.1       cgd       825: bad:
1.13    ! mycroft   826:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
        !           827:        icmp_error(m, type, code, 0, 0);
        !           828:        ipstat.ips_badoptions++;
1.1       cgd       829:        return (1);
                    830: }
                    831:
                    832: /*
                    833:  * Given address of next destination (final or next hop),
                    834:  * return internet address info of interface to be used to get there.
                    835:  */
                    836: struct in_ifaddr *
                    837: ip_rtaddr(dst)
                    838:         struct in_addr dst;
                    839: {
                    840:        register struct sockaddr_in *sin;
                    841:
                    842:        sin = (struct sockaddr_in *) &ipforward_rt.ro_dst;
                    843:
                    844:        if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
                    845:                if (ipforward_rt.ro_rt) {
                    846:                        RTFREE(ipforward_rt.ro_rt);
                    847:                        ipforward_rt.ro_rt = 0;
                    848:                }
                    849:                sin->sin_family = AF_INET;
                    850:                sin->sin_len = sizeof(*sin);
                    851:                sin->sin_addr = dst;
                    852:
                    853:                rtalloc(&ipforward_rt);
                    854:        }
                    855:        if (ipforward_rt.ro_rt == 0)
                    856:                return ((struct in_ifaddr *)0);
                    857:        return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa);
                    858: }
                    859:
                    860: /*
                    861:  * Save incoming source route for use in replies,
                    862:  * to be picked up later by ip_srcroute if the receiver is interested.
                    863:  */
1.13    ! mycroft   864: void
1.1       cgd       865: save_rte(option, dst)
                    866:        u_char *option;
                    867:        struct in_addr dst;
                    868: {
                    869:        unsigned olen;
                    870:
                    871:        olen = option[IPOPT_OLEN];
                    872: #ifdef DIAGNOSTIC
                    873:        if (ipprintfs)
                    874:                printf("save_rte: olen %d\n", olen);
                    875: #endif
                    876:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    877:                return;
                    878:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    879:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    880:        ip_srcrt.dst = dst;
                    881: }
                    882:
                    883: /*
                    884:  * Retrieve incoming source route for use in replies,
                    885:  * in the same form used by setsockopt.
                    886:  * The first hop is placed before the options, will be removed later.
                    887:  */
                    888: struct mbuf *
                    889: ip_srcroute()
                    890: {
                    891:        register struct in_addr *p, *q;
                    892:        register struct mbuf *m;
                    893:
                    894:        if (ip_nhops == 0)
                    895:                return ((struct mbuf *)0);
                    896:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    897:        if (m == 0)
                    898:                return ((struct mbuf *)0);
                    899:
1.13    ! mycroft   900: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       901:
                    902:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    903:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    904:            OPTSIZ;
                    905: #ifdef DIAGNOSTIC
                    906:        if (ipprintfs)
                    907:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
                    908: #endif
                    909:
                    910:        /*
                    911:         * First save first hop for return route
                    912:         */
                    913:        p = &ip_srcrt.route[ip_nhops - 1];
                    914:        *(mtod(m, struct in_addr *)) = *p--;
                    915: #ifdef DIAGNOSTIC
                    916:        if (ipprintfs)
                    917:                printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr));
                    918: #endif
                    919:
                    920:        /*
                    921:         * Copy option fields and padding (nop) to mbuf.
                    922:         */
                    923:        ip_srcrt.nop = IPOPT_NOP;
                    924:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    925:        bcopy((caddr_t)&ip_srcrt.nop,
                    926:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    927:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    928:            sizeof(struct in_addr) + OPTSIZ);
                    929: #undef OPTSIZ
                    930:        /*
                    931:         * Record return path as an IP source route,
                    932:         * reversing the path (pointers are now aligned).
                    933:         */
                    934:        while (p >= ip_srcrt.route) {
                    935: #ifdef DIAGNOSTIC
                    936:                if (ipprintfs)
                    937:                        printf(" %lx", ntohl(q->s_addr));
                    938: #endif
                    939:                *q++ = *p--;
                    940:        }
                    941:        /*
                    942:         * Last hop goes to final destination.
                    943:         */
                    944:        *q = ip_srcrt.dst;
                    945: #ifdef DIAGNOSTIC
                    946:        if (ipprintfs)
                    947:                printf(" %lx\n", ntohl(q->s_addr));
                    948: #endif
                    949:        return (m);
                    950: }
                    951:
                    952: /*
                    953:  * Strip out IP options, at higher
                    954:  * level protocol in the kernel.
                    955:  * Second argument is buffer to which options
                    956:  * will be moved, and return value is their length.
                    957:  * XXX should be deleted; last arg currently ignored.
                    958:  */
1.8       mycroft   959: void
1.1       cgd       960: ip_stripoptions(m, mopt)
                    961:        register struct mbuf *m;
                    962:        struct mbuf *mopt;
                    963: {
                    964:        register int i;
                    965:        struct ip *ip = mtod(m, struct ip *);
                    966:        register caddr_t opts;
                    967:        int olen;
                    968:
                    969:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                    970:        opts = (caddr_t)(ip + 1);
                    971:        i = m->m_len - (sizeof (struct ip) + olen);
                    972:        bcopy(opts  + olen, opts, (unsigned)i);
                    973:        m->m_len -= olen;
                    974:        if (m->m_flags & M_PKTHDR)
                    975:                m->m_pkthdr.len -= olen;
                    976:        ip->ip_hl = sizeof(struct ip) >> 2;
                    977: }
                    978:
                    979: u_char inetctlerrmap[PRC_NCMDS] = {
                    980:        0,              0,              0,              0,
                    981:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                    982:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                    983:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                    984:        0,              0,              0,              0,
                    985:        ENOPROTOOPT
                    986: };
                    987:
                    988: /*
                    989:  * Forward a packet.  If some error occurs return the sender
                    990:  * an icmp packet.  Note we can't always generate a meaningful
                    991:  * icmp message because icmp doesn't have a large enough repertoire
                    992:  * of codes and types.
                    993:  *
                    994:  * If not forwarding, just drop the packet.  This could be confusing
                    995:  * if ipforwarding was zero but some routing protocol was advancing
                    996:  * us as a gateway to somewhere.  However, we must let the routing
                    997:  * protocol deal with that.
                    998:  *
                    999:  * The srcrt parameter indicates whether the packet is being forwarded
                   1000:  * via a source route.
                   1001:  */
1.13    ! mycroft  1002: void
1.1       cgd      1003: ip_forward(m, srcrt)
                   1004:        struct mbuf *m;
                   1005:        int srcrt;
                   1006: {
                   1007:        register struct ip *ip = mtod(m, struct ip *);
                   1008:        register struct sockaddr_in *sin;
                   1009:        register struct rtentry *rt;
                   1010:        int error, type = 0, code;
                   1011:        struct mbuf *mcopy;
1.13    ! mycroft  1012:        n_long dest;
        !          1013:        struct ifnet *destifp;
1.1       cgd      1014:
1.13    ! mycroft  1015:        dest = 0;
1.1       cgd      1016: #ifdef DIAGNOSTIC
                   1017:        if (ipprintfs)
                   1018:                printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
                   1019:                        ip->ip_dst, ip->ip_ttl);
                   1020: #endif
                   1021:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1022:                ipstat.ips_cantforward++;
                   1023:                m_freem(m);
                   1024:                return;
                   1025:        }
                   1026:        HTONS(ip->ip_id);
                   1027:        if (ip->ip_ttl <= IPTTLDEC) {
1.13    ! mycroft  1028:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1029:                return;
                   1030:        }
                   1031:        ip->ip_ttl -= IPTTLDEC;
                   1032:
                   1033:        sin = (struct sockaddr_in *)&ipforward_rt.ro_dst;
                   1034:        if ((rt = ipforward_rt.ro_rt) == 0 ||
                   1035:            ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
                   1036:                if (ipforward_rt.ro_rt) {
                   1037:                        RTFREE(ipforward_rt.ro_rt);
                   1038:                        ipforward_rt.ro_rt = 0;
                   1039:                }
                   1040:                sin->sin_family = AF_INET;
                   1041:                sin->sin_len = sizeof(*sin);
                   1042:                sin->sin_addr = ip->ip_dst;
                   1043:
                   1044:                rtalloc(&ipforward_rt);
                   1045:                if (ipforward_rt.ro_rt == 0) {
1.13    ! mycroft  1046:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1047:                        return;
                   1048:                }
                   1049:                rt = ipforward_rt.ro_rt;
                   1050:        }
                   1051:
                   1052:        /*
                   1053:         * Save at most 64 bytes of the packet in case
                   1054:         * we need to generate an ICMP message to the src.
                   1055:         */
                   1056:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
                   1057:
                   1058: #ifdef GATEWAY
                   1059:        ip_ifmatrix[rt->rt_ifp->if_index +
                   1060:             if_index * m->m_pkthdr.rcvif->if_index]++;
                   1061: #endif
                   1062:        /*
                   1063:         * If forwarding packet using same interface that it came in on,
                   1064:         * perhaps should send a redirect to sender to shortcut a hop.
                   1065:         * Only send redirect if source is sending directly to us,
                   1066:         * and if packet was not source routed (or has any options).
                   1067:         * Also, don't send redirect if forwarding using a default route
                   1068:         * or a route modified by a redirect.
                   1069:         */
                   1070: #define        satosin(sa)     ((struct sockaddr_in *)(sa))
                   1071:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1072:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
                   1073:            satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
                   1074:            ipsendredirects && !srcrt) {
1.13    ! mycroft  1075: #define        RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1.1       cgd      1076:                u_long src = ntohl(ip->ip_src.s_addr);
                   1077:
1.13    ! mycroft  1078:                if (RTA(rt) &&
        !          1079:                    (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1.1       cgd      1080:                    if (rt->rt_flags & RTF_GATEWAY)
1.13    ! mycroft  1081:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1082:                    else
1.13    ! mycroft  1083:                        dest = ip->ip_dst.s_addr;
        !          1084:                    /* Router requirements says to only send host redirects */
1.1       cgd      1085:                    type = ICMP_REDIRECT;
1.13    ! mycroft  1086:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1087: #ifdef DIAGNOSTIC
                   1088:                    if (ipprintfs)
1.13    ! mycroft  1089:                        printf("redirect (%d) to %lx\n", code, (u_long)dest);
1.1       cgd      1090: #endif
                   1091:                }
                   1092:        }
                   1093:
1.13    ! mycroft  1094:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt, IP_FORWARDING
1.9       mycroft  1095: #ifdef DIRECTED_BROADCAST
1.13    ! mycroft  1096:                            | IP_ALLOWBROADCAST
1.9       mycroft  1097: #endif
1.13    ! mycroft  1098:                                                , 0);
1.1       cgd      1099:        if (error)
                   1100:                ipstat.ips_cantforward++;
                   1101:        else {
                   1102:                ipstat.ips_forward++;
                   1103:                if (type)
                   1104:                        ipstat.ips_redirectsent++;
                   1105:                else {
                   1106:                        if (mcopy)
                   1107:                                m_freem(mcopy);
                   1108:                        return;
                   1109:                }
                   1110:        }
                   1111:        if (mcopy == NULL)
                   1112:                return;
1.13    ! mycroft  1113:        destifp = NULL;
        !          1114:
1.1       cgd      1115:        switch (error) {
                   1116:
                   1117:        case 0:                         /* forwarded, but need redirect */
                   1118:                /* type, code set above */
                   1119:                break;
                   1120:
                   1121:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1122:        case EHOSTUNREACH:
                   1123:        case ENETDOWN:
                   1124:        case EHOSTDOWN:
                   1125:        default:
                   1126:                type = ICMP_UNREACH;
                   1127:                code = ICMP_UNREACH_HOST;
                   1128:                break;
                   1129:
                   1130:        case EMSGSIZE:
                   1131:                type = ICMP_UNREACH;
                   1132:                code = ICMP_UNREACH_NEEDFRAG;
1.13    ! mycroft  1133:                if (ipforward_rt.ro_rt)
        !          1134:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1135:                ipstat.ips_cantfrag++;
                   1136:                break;
                   1137:
                   1138:        case ENOBUFS:
                   1139:                type = ICMP_SOURCEQUENCH;
                   1140:                code = 0;
                   1141:                break;
                   1142:        }
1.13    ! mycroft  1143:        icmp_error(mcopy, type, code, dest, destifp);
        !          1144: }
        !          1145:
        !          1146: int
        !          1147: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
        !          1148:        int *name;
        !          1149:        u_int namelen;
        !          1150:        void *oldp;
        !          1151:        size_t *oldlenp;
        !          1152:        void *newp;
        !          1153:        size_t newlen;
        !          1154: {
        !          1155:        /* All sysctl names at this level are terminal. */
        !          1156:        if (namelen != 1)
        !          1157:                return (ENOTDIR);
        !          1158:
        !          1159:        switch (name[0]) {
        !          1160:        case IPCTL_FORWARDING:
        !          1161:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
        !          1162:        case IPCTL_SENDREDIRECTS:
        !          1163:                return (sysctl_int(oldp, oldlenp, newp, newlen,
        !          1164:                        &ipsendredirects));
        !          1165:        case IPCTL_DEFTTL:
        !          1166:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
        !          1167: #ifdef notyet
        !          1168:        case IPCTL_DEFMTU:
        !          1169:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
        !          1170: #endif
        !          1171:        default:
        !          1172:                return (EOPNOTSUPP);
        !          1173:        }
        !          1174:        /* NOTREACHED */
1.1       cgd      1175: }

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