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Annotation of src/sys/netinet/ip_input.c, Revision 1.25

1.25    ! cgd         1: /*     $NetBSD: ip_input.c,v 1.24 1995/08/12 23:59:36 mycroft Exp $    */
1.14      cgd         2:
1.1       cgd         3: /*
1.13      mycroft     4:  * Copyright (c) 1982, 1986, 1988, 1993
                      5:  *     The Regents of the University of California.  All rights reserved.
1.1       cgd         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. All advertising materials mentioning features or use of this software
                     16:  *    must display the following acknowledgement:
                     17:  *     This product includes software developed by the University of
                     18:  *     California, Berkeley and its contributors.
                     19:  * 4. Neither the name of the University nor the names of its contributors
                     20:  *    may be used to endorse or promote products derived from this software
                     21:  *    without specific prior written permission.
                     22:  *
                     23:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     24:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     25:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     26:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     27:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     28:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     29:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     30:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     31:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     32:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     33:  * SUCH DAMAGE.
                     34:  *
1.14      cgd        35:  *     @(#)ip_input.c  8.2 (Berkeley) 1/4/94
1.1       cgd        36:  */
                     37:
1.5       mycroft    38: #include <sys/param.h>
                     39: #include <sys/systm.h>
                     40: #include <sys/malloc.h>
                     41: #include <sys/mbuf.h>
                     42: #include <sys/domain.h>
                     43: #include <sys/protosw.h>
                     44: #include <sys/socket.h>
                     45: #include <sys/errno.h>
                     46: #include <sys/time.h>
                     47: #include <sys/kernel.h>
1.1       cgd        48:
1.5       mycroft    49: #include <net/if.h>
                     50: #include <net/route.h>
1.1       cgd        51:
1.5       mycroft    52: #include <netinet/in.h>
                     53: #include <netinet/in_systm.h>
                     54: #include <netinet/ip.h>
                     55: #include <netinet/in_pcb.h>
                     56: #include <netinet/in_var.h>
                     57: #include <netinet/ip_var.h>
                     58: #include <netinet/ip_icmp.h>
1.1       cgd        59:
                     60: #ifndef        IPFORWARDING
                     61: #ifdef GATEWAY
                     62: #define        IPFORWARDING    1       /* forward IP packets not for us */
                     63: #else /* GATEWAY */
                     64: #define        IPFORWARDING    0       /* don't forward IP packets not for us */
                     65: #endif /* GATEWAY */
                     66: #endif /* IPFORWARDING */
                     67: #ifndef        IPSENDREDIRECTS
                     68: #define        IPSENDREDIRECTS 1
                     69: #endif
                     70: int    ipforwarding = IPFORWARDING;
                     71: int    ipsendredirects = IPSENDREDIRECTS;
1.13      mycroft    72: int    ip_defttl = IPDEFTTL;
1.1       cgd        73: #ifdef DIAGNOSTIC
                     74: int    ipprintfs = 0;
                     75: #endif
                     76:
                     77: extern struct domain inetdomain;
                     78: extern struct protosw inetsw[];
                     79: u_char ip_protox[IPPROTO_MAX];
                     80: int    ipqmaxlen = IFQ_MAXLEN;
1.22      mycroft    81: struct in_ifaddrhead in_ifaddr;
1.13      mycroft    82: struct ifqueue ipintrq;
1.1       cgd        83:
                     84: /*
                     85:  * We need to save the IP options in case a protocol wants to respond
                     86:  * to an incoming packet over the same route if the packet got here
                     87:  * using IP source routing.  This allows connection establishment and
                     88:  * maintenance when the remote end is on a network that is not known
                     89:  * to us.
                     90:  */
                     91: int    ip_nhops = 0;
                     92: static struct ip_srcrt {
                     93:        struct  in_addr dst;                    /* final destination */
                     94:        char    nop;                            /* one NOP to align */
                     95:        char    srcopt[IPOPT_OFFSET + 1];       /* OPTVAL, OLEN and OFFSET */
                     96:        struct  in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
                     97: } ip_srcrt;
                     98:
1.13      mycroft    99: static void save_rte __P((u_char *, struct in_addr));
1.1       cgd       100: /*
                    101:  * IP initialization: fill in IP protocol switch table.
                    102:  * All protocols not implemented in kernel go to raw IP protocol handler.
                    103:  */
1.8       mycroft   104: void
1.1       cgd       105: ip_init()
                    106: {
                    107:        register struct protosw *pr;
                    108:        register int i;
                    109:
                    110:        pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
                    111:        if (pr == 0)
                    112:                panic("ip_init");
                    113:        for (i = 0; i < IPPROTO_MAX; i++)
                    114:                ip_protox[i] = pr - inetsw;
                    115:        for (pr = inetdomain.dom_protosw;
                    116:            pr < inetdomain.dom_protoswNPROTOSW; pr++)
                    117:                if (pr->pr_domain->dom_family == PF_INET &&
                    118:                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
                    119:                        ip_protox[pr->pr_protocol] = pr - inetsw;
1.25    ! cgd       120:        LIST_INIT(&ipq);
1.1       cgd       121:        ip_id = time.tv_sec & 0xffff;
                    122:        ipintrq.ifq_maxlen = ipqmaxlen;
1.22      mycroft   123:        TAILQ_INIT(&in_ifaddr);
1.1       cgd       124: }
                    125:
                    126: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    127: struct route ipforward_rt;
                    128:
                    129: /*
                    130:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    131:  * try to reassemble.  Process options.  Pass to next level.
                    132:  */
1.8       mycroft   133: void
1.1       cgd       134: ipintr()
                    135: {
                    136:        register struct ip *ip;
                    137:        register struct mbuf *m;
                    138:        register struct ipq *fp;
                    139:        register struct in_ifaddr *ia;
1.25    ! cgd       140:        struct ipqent *ipqe;
        !           141:        int hlen, mff, s;
1.1       cgd       142:
                    143: next:
                    144:        /*
                    145:         * Get next datagram off input queue and get IP header
                    146:         * in first mbuf.
                    147:         */
                    148:        s = splimp();
                    149:        IF_DEQUEUE(&ipintrq, m);
                    150:        splx(s);
1.13      mycroft   151:        if (m == 0)
1.1       cgd       152:                return;
                    153: #ifdef DIAGNOSTIC
                    154:        if ((m->m_flags & M_PKTHDR) == 0)
                    155:                panic("ipintr no HDR");
                    156: #endif
                    157:        /*
                    158:         * If no IP addresses have been set yet but the interfaces
                    159:         * are receiving, can't do anything with incoming packets yet.
                    160:         */
1.22      mycroft   161:        if (in_ifaddr.tqh_first == 0)
1.1       cgd       162:                goto bad;
                    163:        ipstat.ips_total++;
                    164:        if (m->m_len < sizeof (struct ip) &&
                    165:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    166:                ipstat.ips_toosmall++;
                    167:                goto next;
                    168:        }
                    169:        ip = mtod(m, struct ip *);
1.13      mycroft   170:        if (ip->ip_v != IPVERSION) {
                    171:                ipstat.ips_badvers++;
                    172:                goto bad;
                    173:        }
1.1       cgd       174:        hlen = ip->ip_hl << 2;
                    175:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    176:                ipstat.ips_badhlen++;
                    177:                goto bad;
                    178:        }
                    179:        if (hlen > m->m_len) {
                    180:                if ((m = m_pullup(m, hlen)) == 0) {
                    181:                        ipstat.ips_badhlen++;
                    182:                        goto next;
                    183:                }
                    184:                ip = mtod(m, struct ip *);
                    185:        }
                    186:        if (ip->ip_sum = in_cksum(m, hlen)) {
                    187:                ipstat.ips_badsum++;
                    188:                goto bad;
                    189:        }
                    190:
                    191:        /*
                    192:         * Convert fields to host representation.
                    193:         */
                    194:        NTOHS(ip->ip_len);
                    195:        if (ip->ip_len < hlen) {
                    196:                ipstat.ips_badlen++;
                    197:                goto bad;
                    198:        }
                    199:        NTOHS(ip->ip_id);
                    200:        NTOHS(ip->ip_off);
                    201:
                    202:        /*
                    203:         * Check that the amount of data in the buffers
                    204:         * is as at least much as the IP header would have us expect.
                    205:         * Trim mbufs if longer than we expect.
                    206:         * Drop packet if shorter than we expect.
                    207:         */
                    208:        if (m->m_pkthdr.len < ip->ip_len) {
                    209:                ipstat.ips_tooshort++;
                    210:                goto bad;
                    211:        }
                    212:        if (m->m_pkthdr.len > ip->ip_len) {
                    213:                if (m->m_len == m->m_pkthdr.len) {
                    214:                        m->m_len = ip->ip_len;
                    215:                        m->m_pkthdr.len = ip->ip_len;
                    216:                } else
                    217:                        m_adj(m, ip->ip_len - m->m_pkthdr.len);
                    218:        }
                    219:
                    220:        /*
                    221:         * Process options and, if not destined for us,
                    222:         * ship it on.  ip_dooptions returns 1 when an
                    223:         * error was detected (causing an icmp message
                    224:         * to be sent and the original packet to be freed).
                    225:         */
                    226:        ip_nhops = 0;           /* for source routed packets */
                    227:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    228:                goto next;
                    229:
                    230:        /*
                    231:         * Check our list of addresses, to see if the packet is for us.
                    232:         */
1.22      mycroft   233:        for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
1.20      mycroft   234:                if (ip->ip_dst.s_addr == ia->ia_addr.sin_addr.s_addr)
1.1       cgd       235:                        goto ours;
                    236:                if (
                    237: #ifdef DIRECTED_BROADCAST
                    238:                    ia->ia_ifp == m->m_pkthdr.rcvif &&
                    239: #endif
                    240:                    (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.20      mycroft   241:                        if (ip->ip_dst.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
                    242:                            ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr ||
                    243:                            /*
                    244:                             * Look for all-0's host part (old broadcast addr),
                    245:                             * either for subnet or net.
                    246:                             */
                    247:                            ip->ip_dst.s_addr == ia->ia_subnet ||
1.18      mycroft   248:                            ip->ip_dst.s_addr == ia->ia_net)
1.1       cgd       249:                                goto ours;
                    250:                }
                    251:        }
1.18      mycroft   252:        if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4       hpeyerl   253:                struct in_multi *inm;
                    254: #ifdef MROUTING
                    255:                extern struct socket *ip_mrouter;
1.10      brezak    256:
                    257:                if (m->m_flags & M_EXT) {
                    258:                        if ((m = m_pullup(m, hlen)) == 0) {
                    259:                                ipstat.ips_toosmall++;
                    260:                                goto next;
                    261:                        }
                    262:                        ip = mtod(m, struct ip *);
                    263:                }
1.4       hpeyerl   264:
                    265:                if (ip_mrouter) {
                    266:                        /*
                    267:                         * If we are acting as a multicast router, all
                    268:                         * incoming multicast packets are passed to the
                    269:                         * kernel-level multicast forwarding function.
                    270:                         * The packet is returned (relatively) intact; if
                    271:                         * ip_mforward() returns a non-zero value, the packet
                    272:                         * must be discarded, else it may be accepted below.
                    273:                         *
                    274:                         * (The IP ident field is put in the same byte order
                    275:                         * as expected when ip_mforward() is called from
                    276:                         * ip_output().)
                    277:                         */
                    278:                        ip->ip_id = htons(ip->ip_id);
1.13      mycroft   279:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    280:                                ipstat.ips_cantforward++;
1.4       hpeyerl   281:                                m_freem(m);
                    282:                                goto next;
                    283:                        }
                    284:                        ip->ip_id = ntohs(ip->ip_id);
                    285:
                    286:                        /*
                    287:                         * The process-level routing demon needs to receive
                    288:                         * all multicast IGMP packets, whether or not this
                    289:                         * host belongs to their destination groups.
                    290:                         */
                    291:                        if (ip->ip_p == IPPROTO_IGMP)
                    292:                                goto ours;
1.13      mycroft   293:                        ipstat.ips_forward++;
1.4       hpeyerl   294:                }
                    295: #endif
                    296:                /*
                    297:                 * See if we belong to the destination multicast group on the
                    298:                 * arrival interface.
                    299:                 */
                    300:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    301:                if (inm == NULL) {
1.13      mycroft   302:                        ipstat.ips_cantforward++;
1.4       hpeyerl   303:                        m_freem(m);
                    304:                        goto next;
                    305:                }
                    306:                goto ours;
                    307:        }
1.19      mycroft   308:        if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
                    309:            ip->ip_dst.s_addr == INADDR_ANY)
1.1       cgd       310:                goto ours;
                    311:
                    312:        /*
                    313:         * Not for us; forward if possible and desirable.
                    314:         */
                    315:        if (ipforwarding == 0) {
                    316:                ipstat.ips_cantforward++;
                    317:                m_freem(m);
                    318:        } else
                    319:                ip_forward(m, 0);
                    320:        goto next;
                    321:
                    322: ours:
                    323:        /*
                    324:         * If offset or IP_MF are set, must reassemble.
                    325:         * Otherwise, nothing need be done.
                    326:         * (We could look in the reassembly queue to see
                    327:         * if the packet was previously fragmented,
                    328:         * but it's not worth the time; just let them time out.)
                    329:         */
                    330:        if (ip->ip_off &~ IP_DF) {
                    331:                if (m->m_flags & M_EXT) {               /* XXX */
                    332:                        if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
                    333:                                ipstat.ips_toosmall++;
                    334:                                goto next;
                    335:                        }
                    336:                        ip = mtod(m, struct ip *);
                    337:                }
                    338:                /*
                    339:                 * Look for queue of fragments
                    340:                 * of this datagram.
                    341:                 */
1.25    ! cgd       342:                for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1       cgd       343:                        if (ip->ip_id == fp->ipq_id &&
                    344:                            ip->ip_src.s_addr == fp->ipq_src.s_addr &&
                    345:                            ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
                    346:                            ip->ip_p == fp->ipq_p)
                    347:                                goto found;
                    348:                fp = 0;
                    349: found:
                    350:
                    351:                /*
                    352:                 * Adjust ip_len to not reflect header,
1.25    ! cgd       353:                 * set ipqe_mff if more fragments are expected,
1.1       cgd       354:                 * convert offset of this to bytes.
                    355:                 */
                    356:                ip->ip_len -= hlen;
1.25    ! cgd       357:                mff = (ip->ip_off & IP_MF) != 0;
        !           358:                if (mff) {
1.16      cgd       359:                        /*
                    360:                         * Make sure that fragments have a data length
                    361:                         * that's a non-zero multiple of 8 bytes.
                    362:                         */
1.17      cgd       363:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16      cgd       364:                                ipstat.ips_badfrags++;
                    365:                                goto bad;
                    366:                        }
                    367:                }
1.1       cgd       368:                ip->ip_off <<= 3;
                    369:
                    370:                /*
                    371:                 * If datagram marked as having more fragments
                    372:                 * or if this is not the first fragment,
                    373:                 * attempt reassembly; if it succeeds, proceed.
                    374:                 */
1.25    ! cgd       375:                if (mff || ip->ip_off) {
1.1       cgd       376:                        ipstat.ips_fragments++;
1.25    ! cgd       377:                        MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent),
        !           378:                            M_IPQ, M_NOWAIT);
        !           379:                        if (ipqe == NULL) {
        !           380:                                ipstat.ips_rcvmemdrop++;
        !           381:                                goto bad;
        !           382:                        }
        !           383:                        ipqe->ipqe_mff = mff;
        !           384:                        ipqe->ipqe_ip = ip;
        !           385:                        ip = ip_reass(ipqe, fp);
1.1       cgd       386:                        if (ip == 0)
                    387:                                goto next;
1.13      mycroft   388:                        ipstat.ips_reassembled++;
1.1       cgd       389:                        m = dtom(ip);
                    390:                } else
                    391:                        if (fp)
                    392:                                ip_freef(fp);
                    393:        } else
                    394:                ip->ip_len -= hlen;
                    395:
                    396:        /*
                    397:         * Switch out to protocol's input routine.
                    398:         */
                    399:        ipstat.ips_delivered++;
                    400:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    401:        goto next;
                    402: bad:
                    403:        m_freem(m);
                    404:        goto next;
                    405: }
                    406:
                    407: /*
                    408:  * Take incoming datagram fragment and try to
                    409:  * reassemble it into whole datagram.  If a chain for
                    410:  * reassembly of this datagram already exists, then it
                    411:  * is given as fp; otherwise have to make a chain.
                    412:  */
                    413: struct ip *
1.25    ! cgd       414: ip_reass(ipqe, fp)
        !           415:        register struct ipqent *ipqe;
1.1       cgd       416:        register struct ipq *fp;
                    417: {
1.25    ! cgd       418:        register struct mbuf *m = dtom(ipqe->ipqe_ip);
        !           419:        register struct ipqent *nq, *p, *q;
        !           420:        struct ip *ip;
1.1       cgd       421:        struct mbuf *t;
1.25    ! cgd       422:        int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1       cgd       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 *);
1.25    ! cgd       439:                LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1       cgd       440:                fp->ipq_ttl = IPFRAGTTL;
1.25    ! cgd       441:                fp->ipq_p = ipqe->ipqe_ip->ip_p;
        !           442:                fp->ipq_id = ipqe->ipqe_ip->ip_id;
        !           443:                LIST_INIT(&fp->ipq_fragq);
        !           444:                fp->ipq_src = ipqe->ipqe_ip->ip_src;
        !           445:                fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
        !           446:                p = NULL;
1.1       cgd       447:                goto insert;
                    448:        }
                    449:
                    450:        /*
                    451:         * Find a segment which begins after this one does.
                    452:         */
1.25    ! cgd       453:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
        !           454:            p = q, q = q->ipqe_q.le_next)
        !           455:                if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1       cgd       456:                        break;
                    457:
                    458:        /*
                    459:         * If there is a preceding segment, it may provide some of
                    460:         * our data already.  If so, drop the data from the incoming
                    461:         * segment.  If it provides all of our data, drop us.
                    462:         */
1.25    ! cgd       463:        if (p != NULL) {
        !           464:                i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
        !           465:                    ipqe->ipqe_ip->ip_off;
1.1       cgd       466:                if (i > 0) {
1.25    ! cgd       467:                        if (i >= ipqe->ipqe_ip->ip_len)
1.1       cgd       468:                                goto dropfrag;
1.25    ! cgd       469:                        m_adj(dtom(ipqe->ipqe_ip), i);
        !           470:                        ipqe->ipqe_ip->ip_off += i;
        !           471:                        ipqe->ipqe_ip->ip_len -= i;
1.1       cgd       472:                }
                    473:        }
                    474:
                    475:        /*
                    476:         * While we overlap succeeding segments trim them or,
                    477:         * if they are completely covered, dequeue them.
                    478:         */
1.25    ! cgd       479:        for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
        !           480:            q->ipqe_ip->ip_off; q = nq) {
        !           481:                i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
        !           482:                    q->ipqe_ip->ip_off;
        !           483:                if (i < q->ipqe_ip->ip_len) {
        !           484:                        q->ipqe_ip->ip_len -= i;
        !           485:                        q->ipqe_ip->ip_off += i;
        !           486:                        m_adj(dtom(q->ipqe_ip), i);
1.1       cgd       487:                        break;
                    488:                }
1.25    ! cgd       489:                nq = q->ipqe_q.le_next;
        !           490:                m_freem(dtom(q->ipqe_ip));
        !           491:                LIST_REMOVE(q, ipqe_q);
        !           492:                FREE(q, M_IPQ);
1.1       cgd       493:        }
                    494:
                    495: insert:
                    496:        /*
                    497:         * Stick new segment in its place;
                    498:         * check for complete reassembly.
                    499:         */
1.25    ! cgd       500:        if (p == NULL) {
        !           501:                LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
        !           502:        } else {
        !           503:                LIST_INSERT_AFTER(p, ipqe, ipqe_q);
        !           504:        }
1.1       cgd       505:        next = 0;
1.25    ! cgd       506:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
        !           507:            p = q, q = q->ipqe_q.le_next) {
        !           508:                if (q->ipqe_ip->ip_off != next)
1.1       cgd       509:                        return (0);
1.25    ! cgd       510:                next += q->ipqe_ip->ip_len;
1.1       cgd       511:        }
1.25    ! cgd       512:        if (p->ipqe_mff)
1.1       cgd       513:                return (0);
                    514:
                    515:        /*
                    516:         * Reassembly is complete; concatenate fragments.
                    517:         */
1.25    ! cgd       518:        q = fp->ipq_fragq.lh_first;
        !           519:        ip = q->ipqe_ip;
        !           520:        m = dtom(q->ipqe_ip);
1.1       cgd       521:        t = m->m_next;
                    522:        m->m_next = 0;
                    523:        m_cat(m, t);
1.25    ! cgd       524:        nq = q->ipqe_q.le_next;
        !           525:        FREE(q, M_IPQ);
        !           526:        for (q = nq; q != NULL; q = nq) {
        !           527:                t = dtom(q->ipqe_ip);
        !           528:                nq = q->ipqe_q.le_next;
        !           529:                FREE(q, M_IPQ);
1.1       cgd       530:                m_cat(m, t);
                    531:        }
                    532:
                    533:        /*
                    534:         * Create header for new ip packet by
                    535:         * modifying header of first packet;
                    536:         * dequeue and discard fragment reassembly header.
                    537:         * Make header visible.
                    538:         */
                    539:        ip->ip_len = next;
1.25    ! cgd       540:        ip->ip_src = fp->ipq_src;
        !           541:        ip->ip_dst = fp->ipq_dst;
        !           542:        LIST_REMOVE(fp, ipq_q);
1.1       cgd       543:        (void) m_free(dtom(fp));
                    544:        m->m_len += (ip->ip_hl << 2);
                    545:        m->m_data -= (ip->ip_hl << 2);
                    546:        /* some debugging cruft by sklower, below, will go away soon */
                    547:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
                    548:                register int plen = 0;
                    549:                for (t = m; m; m = m->m_next)
                    550:                        plen += m->m_len;
                    551:                t->m_pkthdr.len = plen;
                    552:        }
1.25    ! cgd       553:        return (ip);
1.1       cgd       554:
                    555: dropfrag:
                    556:        ipstat.ips_fragdropped++;
                    557:        m_freem(m);
1.25    ! cgd       558:        FREE(ipqe, M_IPQ);
1.1       cgd       559:        return (0);
                    560: }
                    561:
                    562: /*
                    563:  * Free a fragment reassembly header and all
                    564:  * associated datagrams.
                    565:  */
1.8       mycroft   566: void
1.1       cgd       567: ip_freef(fp)
                    568:        struct ipq *fp;
                    569: {
1.25    ! cgd       570:        register struct ipqent *q, *p;
1.1       cgd       571:
1.25    ! cgd       572:        for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
        !           573:                p = q->ipqe_q.le_next;
        !           574:                m_freem(dtom(q->ipqe_ip));
        !           575:                LIST_REMOVE(q, ipqe_q);
        !           576:                FREE(q, M_IPQ);
1.1       cgd       577:        }
1.25    ! cgd       578:        LIST_REMOVE(fp, ipq_q);
1.1       cgd       579:        (void) m_free(dtom(fp));
                    580: }
                    581:
                    582: /*
                    583:  * IP timer processing;
                    584:  * if a timer expires on a reassembly
                    585:  * queue, discard it.
                    586:  */
1.8       mycroft   587: void
1.1       cgd       588: ip_slowtimo()
                    589: {
1.25    ! cgd       590:        register struct ipq *fp, *nfp;
1.24      mycroft   591:        int s = splsoftnet();
1.1       cgd       592:
1.25    ! cgd       593:        for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
        !           594:                nfp = fp->ipq_q.le_next;
        !           595:                if (--fp->ipq_ttl == 0) {
1.1       cgd       596:                        ipstat.ips_fragtimeout++;
1.25    ! cgd       597:                        ip_freef(fp);
1.1       cgd       598:                }
                    599:        }
                    600:        splx(s);
                    601: }
                    602:
                    603: /*
                    604:  * Drain off all datagram fragments.
                    605:  */
1.8       mycroft   606: void
1.1       cgd       607: ip_drain()
                    608: {
                    609:
1.25    ! cgd       610:        while (ipq.lh_first != NULL) {
1.1       cgd       611:                ipstat.ips_fragdropped++;
1.25    ! cgd       612:                ip_freef(ipq.lh_first);
1.1       cgd       613:        }
                    614: }
                    615:
                    616: /*
                    617:  * Do option processing on a datagram,
                    618:  * possibly discarding it if bad options are encountered,
                    619:  * or forwarding it if source-routed.
                    620:  * Returns 1 if packet has been forwarded/freed,
                    621:  * 0 if the packet should be processed further.
                    622:  */
1.8       mycroft   623: int
1.1       cgd       624: ip_dooptions(m)
                    625:        struct mbuf *m;
                    626: {
                    627:        register struct ip *ip = mtod(m, struct ip *);
                    628:        register u_char *cp;
                    629:        register struct ip_timestamp *ipt;
                    630:        register struct in_ifaddr *ia;
                    631:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13      mycroft   632:        struct in_addr *sin, dst;
1.1       cgd       633:        n_time ntime;
                    634:
1.13      mycroft   635:        dst = ip->ip_dst;
1.1       cgd       636:        cp = (u_char *)(ip + 1);
                    637:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    638:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    639:                opt = cp[IPOPT_OPTVAL];
                    640:                if (opt == IPOPT_EOL)
                    641:                        break;
                    642:                if (opt == IPOPT_NOP)
                    643:                        optlen = 1;
                    644:                else {
                    645:                        optlen = cp[IPOPT_OLEN];
                    646:                        if (optlen <= 0 || optlen > cnt) {
                    647:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    648:                                goto bad;
                    649:                        }
                    650:                }
                    651:                switch (opt) {
                    652:
                    653:                default:
                    654:                        break;
                    655:
                    656:                /*
                    657:                 * Source routing with record.
                    658:                 * Find interface with current destination address.
                    659:                 * If none on this machine then drop if strictly routed,
                    660:                 * or do nothing if loosely routed.
                    661:                 * Record interface address and bring up next address
                    662:                 * component.  If strictly routed make sure next
                    663:                 * address is on directly accessible net.
                    664:                 */
                    665:                case IPOPT_LSRR:
                    666:                case IPOPT_SSRR:
                    667:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    668:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    669:                                goto bad;
                    670:                        }
                    671:                        ipaddr.sin_addr = ip->ip_dst;
1.19      mycroft   672:                        ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1       cgd       673:                        if (ia == 0) {
                    674:                                if (opt == IPOPT_SSRR) {
                    675:                                        type = ICMP_UNREACH;
                    676:                                        code = ICMP_UNREACH_SRCFAIL;
                    677:                                        goto bad;
                    678:                                }
                    679:                                /*
                    680:                                 * Loose routing, and not at next destination
                    681:                                 * yet; nothing to do except forward.
                    682:                                 */
                    683:                                break;
                    684:                        }
                    685:                        off--;                  /* 0 origin */
                    686:                        if (off > optlen - sizeof(struct in_addr)) {
                    687:                                /*
                    688:                                 * End of source route.  Should be for us.
                    689:                                 */
                    690:                                save_rte(cp, ip->ip_src);
                    691:                                break;
                    692:                        }
                    693:                        /*
                    694:                         * locate outgoing interface
                    695:                         */
                    696:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    697:                            sizeof(ipaddr.sin_addr));
                    698:                        if (opt == IPOPT_SSRR) {
                    699: #define        INA     struct in_ifaddr *
                    700: #define        SA      struct sockaddr *
                    701:                            if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
1.13      mycroft   702:                                ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1.1       cgd       703:                        } else
                    704:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    705:                        if (ia == 0) {
                    706:                                type = ICMP_UNREACH;
                    707:                                code = ICMP_UNREACH_SRCFAIL;
                    708:                                goto bad;
                    709:                        }
                    710:                        ip->ip_dst = ipaddr.sin_addr;
1.20      mycroft   711:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       712:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    713:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft   714:                        /*
                    715:                         * Let ip_intr's mcast routing check handle mcast pkts
                    716:                         */
1.18      mycroft   717:                        forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1       cgd       718:                        break;
                    719:
                    720:                case IPOPT_RR:
                    721:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    722:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    723:                                goto bad;
                    724:                        }
                    725:                        /*
                    726:                         * If no space remains, ignore.
                    727:                         */
                    728:                        off--;                  /* 0 origin */
                    729:                        if (off > optlen - sizeof(struct in_addr))
                    730:                                break;
                    731:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    732:                            sizeof(ipaddr.sin_addr));
                    733:                        /*
                    734:                         * locate outgoing interface; if we're the destination,
                    735:                         * use the incoming interface (should be same).
                    736:                         */
                    737:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    738:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    739:                                type = ICMP_UNREACH;
                    740:                                code = ICMP_UNREACH_HOST;
                    741:                                goto bad;
                    742:                        }
1.20      mycroft   743:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       744:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    745:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    746:                        break;
                    747:
                    748:                case IPOPT_TS:
                    749:                        code = cp - (u_char *)ip;
                    750:                        ipt = (struct ip_timestamp *)cp;
                    751:                        if (ipt->ipt_len < 5)
                    752:                                goto bad;
1.15      cgd       753:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1       cgd       754:                                if (++ipt->ipt_oflw == 0)
                    755:                                        goto bad;
                    756:                                break;
                    757:                        }
                    758:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    759:                        switch (ipt->ipt_flg) {
                    760:
                    761:                        case IPOPT_TS_TSONLY:
                    762:                                break;
                    763:
                    764:                        case IPOPT_TS_TSANDADDR:
                    765:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    766:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    767:                                        goto bad;
1.13      mycroft   768:                                ipaddr.sin_addr = dst;
                    769:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
                    770:                                                            m->m_pkthdr.rcvif);
                    771:                                if (ia == 0)
                    772:                                        continue;
1.20      mycroft   773:                                bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       774:                                    (caddr_t)sin, sizeof(struct in_addr));
                    775:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    776:                                break;
                    777:
                    778:                        case IPOPT_TS_PRESPEC:
                    779:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    780:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    781:                                        goto bad;
                    782:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    783:                                    sizeof(struct in_addr));
                    784:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    785:                                        continue;
                    786:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    787:                                break;
                    788:
                    789:                        default:
                    790:                                goto bad;
                    791:                        }
                    792:                        ntime = iptime();
                    793:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    794:                            sizeof(n_time));
                    795:                        ipt->ipt_ptr += sizeof(n_time);
                    796:                }
                    797:        }
                    798:        if (forward) {
                    799:                ip_forward(m, 1);
                    800:                return (1);
1.13      mycroft   801:        }
                    802:        return (0);
1.1       cgd       803: bad:
1.13      mycroft   804:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
                    805:        icmp_error(m, type, code, 0, 0);
                    806:        ipstat.ips_badoptions++;
1.1       cgd       807:        return (1);
                    808: }
                    809:
                    810: /*
                    811:  * Given address of next destination (final or next hop),
                    812:  * return internet address info of interface to be used to get there.
                    813:  */
                    814: struct in_ifaddr *
                    815: ip_rtaddr(dst)
                    816:         struct in_addr dst;
                    817: {
                    818:        register struct sockaddr_in *sin;
                    819:
1.19      mycroft   820:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd       821:
                    822:        if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
                    823:                if (ipforward_rt.ro_rt) {
                    824:                        RTFREE(ipforward_rt.ro_rt);
                    825:                        ipforward_rt.ro_rt = 0;
                    826:                }
                    827:                sin->sin_family = AF_INET;
                    828:                sin->sin_len = sizeof(*sin);
                    829:                sin->sin_addr = dst;
                    830:
                    831:                rtalloc(&ipforward_rt);
                    832:        }
                    833:        if (ipforward_rt.ro_rt == 0)
                    834:                return ((struct in_ifaddr *)0);
1.19      mycroft   835:        return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1       cgd       836: }
                    837:
                    838: /*
                    839:  * Save incoming source route for use in replies,
                    840:  * to be picked up later by ip_srcroute if the receiver is interested.
                    841:  */
1.13      mycroft   842: void
1.1       cgd       843: save_rte(option, dst)
                    844:        u_char *option;
                    845:        struct in_addr dst;
                    846: {
                    847:        unsigned olen;
                    848:
                    849:        olen = option[IPOPT_OLEN];
                    850: #ifdef DIAGNOSTIC
                    851:        if (ipprintfs)
                    852:                printf("save_rte: olen %d\n", olen);
                    853: #endif
                    854:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    855:                return;
                    856:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    857:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    858:        ip_srcrt.dst = dst;
                    859: }
                    860:
                    861: /*
                    862:  * Retrieve incoming source route for use in replies,
                    863:  * in the same form used by setsockopt.
                    864:  * The first hop is placed before the options, will be removed later.
                    865:  */
                    866: struct mbuf *
                    867: ip_srcroute()
                    868: {
                    869:        register struct in_addr *p, *q;
                    870:        register struct mbuf *m;
                    871:
                    872:        if (ip_nhops == 0)
                    873:                return ((struct mbuf *)0);
                    874:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    875:        if (m == 0)
                    876:                return ((struct mbuf *)0);
                    877:
1.13      mycroft   878: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       879:
                    880:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    881:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    882:            OPTSIZ;
                    883: #ifdef DIAGNOSTIC
                    884:        if (ipprintfs)
                    885:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
                    886: #endif
                    887:
                    888:        /*
                    889:         * First save first hop for return route
                    890:         */
                    891:        p = &ip_srcrt.route[ip_nhops - 1];
                    892:        *(mtod(m, struct in_addr *)) = *p--;
                    893: #ifdef DIAGNOSTIC
                    894:        if (ipprintfs)
                    895:                printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr));
                    896: #endif
                    897:
                    898:        /*
                    899:         * Copy option fields and padding (nop) to mbuf.
                    900:         */
                    901:        ip_srcrt.nop = IPOPT_NOP;
                    902:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    903:        bcopy((caddr_t)&ip_srcrt.nop,
                    904:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    905:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    906:            sizeof(struct in_addr) + OPTSIZ);
                    907: #undef OPTSIZ
                    908:        /*
                    909:         * Record return path as an IP source route,
                    910:         * reversing the path (pointers are now aligned).
                    911:         */
                    912:        while (p >= ip_srcrt.route) {
                    913: #ifdef DIAGNOSTIC
                    914:                if (ipprintfs)
                    915:                        printf(" %lx", ntohl(q->s_addr));
                    916: #endif
                    917:                *q++ = *p--;
                    918:        }
                    919:        /*
                    920:         * Last hop goes to final destination.
                    921:         */
                    922:        *q = ip_srcrt.dst;
                    923: #ifdef DIAGNOSTIC
                    924:        if (ipprintfs)
                    925:                printf(" %lx\n", ntohl(q->s_addr));
                    926: #endif
                    927:        return (m);
                    928: }
                    929:
                    930: /*
                    931:  * Strip out IP options, at higher
                    932:  * level protocol in the kernel.
                    933:  * Second argument is buffer to which options
                    934:  * will be moved, and return value is their length.
                    935:  * XXX should be deleted; last arg currently ignored.
                    936:  */
1.8       mycroft   937: void
1.1       cgd       938: ip_stripoptions(m, mopt)
                    939:        register struct mbuf *m;
                    940:        struct mbuf *mopt;
                    941: {
                    942:        register int i;
                    943:        struct ip *ip = mtod(m, struct ip *);
                    944:        register caddr_t opts;
                    945:        int olen;
                    946:
                    947:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                    948:        opts = (caddr_t)(ip + 1);
                    949:        i = m->m_len - (sizeof (struct ip) + olen);
                    950:        bcopy(opts  + olen, opts, (unsigned)i);
                    951:        m->m_len -= olen;
                    952:        if (m->m_flags & M_PKTHDR)
                    953:                m->m_pkthdr.len -= olen;
                    954:        ip->ip_hl = sizeof(struct ip) >> 2;
                    955: }
                    956:
1.23      mycroft   957: int inetctlerrmap[PRC_NCMDS] = {
1.1       cgd       958:        0,              0,              0,              0,
                    959:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                    960:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                    961:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                    962:        0,              0,              0,              0,
                    963:        ENOPROTOOPT
                    964: };
                    965:
                    966: /*
                    967:  * Forward a packet.  If some error occurs return the sender
                    968:  * an icmp packet.  Note we can't always generate a meaningful
                    969:  * icmp message because icmp doesn't have a large enough repertoire
                    970:  * of codes and types.
                    971:  *
                    972:  * If not forwarding, just drop the packet.  This could be confusing
                    973:  * if ipforwarding was zero but some routing protocol was advancing
                    974:  * us as a gateway to somewhere.  However, we must let the routing
                    975:  * protocol deal with that.
                    976:  *
                    977:  * The srcrt parameter indicates whether the packet is being forwarded
                    978:  * via a source route.
                    979:  */
1.13      mycroft   980: void
1.1       cgd       981: ip_forward(m, srcrt)
                    982:        struct mbuf *m;
                    983:        int srcrt;
                    984: {
                    985:        register struct ip *ip = mtod(m, struct ip *);
                    986:        register struct sockaddr_in *sin;
                    987:        register struct rtentry *rt;
                    988:        int error, type = 0, code;
                    989:        struct mbuf *mcopy;
1.13      mycroft   990:        n_long dest;
                    991:        struct ifnet *destifp;
1.1       cgd       992:
1.13      mycroft   993:        dest = 0;
1.1       cgd       994: #ifdef DIAGNOSTIC
                    995:        if (ipprintfs)
                    996:                printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
                    997:                        ip->ip_dst, ip->ip_ttl);
                    998: #endif
                    999:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1000:                ipstat.ips_cantforward++;
                   1001:                m_freem(m);
                   1002:                return;
                   1003:        }
                   1004:        HTONS(ip->ip_id);
                   1005:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1006:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1007:                return;
                   1008:        }
                   1009:        ip->ip_ttl -= IPTTLDEC;
                   1010:
1.19      mycroft  1011:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1012:        if ((rt = ipforward_rt.ro_rt) == 0 ||
                   1013:            ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
                   1014:                if (ipforward_rt.ro_rt) {
                   1015:                        RTFREE(ipforward_rt.ro_rt);
                   1016:                        ipforward_rt.ro_rt = 0;
                   1017:                }
                   1018:                sin->sin_family = AF_INET;
                   1019:                sin->sin_len = sizeof(*sin);
                   1020:                sin->sin_addr = ip->ip_dst;
                   1021:
                   1022:                rtalloc(&ipforward_rt);
                   1023:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1024:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1025:                        return;
                   1026:                }
                   1027:                rt = ipforward_rt.ro_rt;
                   1028:        }
                   1029:
                   1030:        /*
                   1031:         * Save at most 64 bytes of the packet in case
                   1032:         * we need to generate an ICMP message to the src.
                   1033:         */
                   1034:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
                   1035:
                   1036:        /*
                   1037:         * If forwarding packet using same interface that it came in on,
                   1038:         * perhaps should send a redirect to sender to shortcut a hop.
                   1039:         * Only send redirect if source is sending directly to us,
                   1040:         * and if packet was not source routed (or has any options).
                   1041:         * Also, don't send redirect if forwarding using a default route
                   1042:         * or a route modified by a redirect.
                   1043:         */
                   1044:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1045:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
                   1046:            satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
                   1047:            ipsendredirects && !srcrt) {
1.19      mycroft  1048:                if (rt->rt_ifa &&
                   1049:                    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
                   1050:                    ifatoia(rt->rt_ifa)->ia_subnet) {
1.1       cgd      1051:                    if (rt->rt_flags & RTF_GATEWAY)
1.13      mycroft  1052:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1053:                    else
1.13      mycroft  1054:                        dest = ip->ip_dst.s_addr;
                   1055:                    /* Router requirements says to only send host redirects */
1.1       cgd      1056:                    type = ICMP_REDIRECT;
1.13      mycroft  1057:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1058: #ifdef DIAGNOSTIC
                   1059:                    if (ipprintfs)
1.15      cgd      1060:                        printf("redirect (%d) to %lx\n", code, (u_int32_t)dest);
1.1       cgd      1061: #endif
                   1062:                }
                   1063:        }
                   1064:
1.13      mycroft  1065:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt, IP_FORWARDING
1.9       mycroft  1066: #ifdef DIRECTED_BROADCAST
1.13      mycroft  1067:                            | IP_ALLOWBROADCAST
1.9       mycroft  1068: #endif
1.13      mycroft  1069:                                                , 0);
1.1       cgd      1070:        if (error)
                   1071:                ipstat.ips_cantforward++;
                   1072:        else {
                   1073:                ipstat.ips_forward++;
                   1074:                if (type)
                   1075:                        ipstat.ips_redirectsent++;
                   1076:                else {
                   1077:                        if (mcopy)
                   1078:                                m_freem(mcopy);
                   1079:                        return;
                   1080:                }
                   1081:        }
                   1082:        if (mcopy == NULL)
                   1083:                return;
1.13      mycroft  1084:        destifp = NULL;
                   1085:
1.1       cgd      1086:        switch (error) {
                   1087:
                   1088:        case 0:                         /* forwarded, but need redirect */
                   1089:                /* type, code set above */
                   1090:                break;
                   1091:
                   1092:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1093:        case EHOSTUNREACH:
                   1094:        case ENETDOWN:
                   1095:        case EHOSTDOWN:
                   1096:        default:
                   1097:                type = ICMP_UNREACH;
                   1098:                code = ICMP_UNREACH_HOST;
                   1099:                break;
                   1100:
                   1101:        case EMSGSIZE:
                   1102:                type = ICMP_UNREACH;
                   1103:                code = ICMP_UNREACH_NEEDFRAG;
1.13      mycroft  1104:                if (ipforward_rt.ro_rt)
                   1105:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1106:                ipstat.ips_cantfrag++;
                   1107:                break;
                   1108:
                   1109:        case ENOBUFS:
                   1110:                type = ICMP_SOURCEQUENCH;
                   1111:                code = 0;
                   1112:                break;
                   1113:        }
1.13      mycroft  1114:        icmp_error(mcopy, type, code, dest, destifp);
                   1115: }
                   1116:
                   1117: int
                   1118: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1119:        int *name;
                   1120:        u_int namelen;
                   1121:        void *oldp;
                   1122:        size_t *oldlenp;
                   1123:        void *newp;
                   1124:        size_t newlen;
                   1125: {
                   1126:        /* All sysctl names at this level are terminal. */
                   1127:        if (namelen != 1)
                   1128:                return (ENOTDIR);
                   1129:
                   1130:        switch (name[0]) {
                   1131:        case IPCTL_FORWARDING:
                   1132:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
                   1133:        case IPCTL_SENDREDIRECTS:
                   1134:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1135:                        &ipsendredirects));
                   1136:        case IPCTL_DEFTTL:
                   1137:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
                   1138: #ifdef notyet
                   1139:        case IPCTL_DEFMTU:
                   1140:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
                   1141: #endif
                   1142:        default:
                   1143:                return (EOPNOTSUPP);
                   1144:        }
                   1145:        /* NOTREACHED */
1.1       cgd      1146: }

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