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Annotation of src/sys/netinet/ip_input.c, Revision 1.26

1.26    ! thorpej     1: /*     $NetBSD: ip_input.c,v 1.25 1995/11/21 01:07:34 cgd 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
1.26    ! thorpej    70: #ifndef IPFORWSRCRT
        !            71: #define        IPFORWSRCRT     1       /* allow source-routed packets */
        !            72: #endif
1.1       cgd        73: int    ipforwarding = IPFORWARDING;
                     74: int    ipsendredirects = IPSENDREDIRECTS;
1.13      mycroft    75: int    ip_defttl = IPDEFTTL;
1.26    ! thorpej    76: int    ip_forwsrcrt = IPFORWSRCRT;
1.1       cgd        77: #ifdef DIAGNOSTIC
                     78: int    ipprintfs = 0;
                     79: #endif
                     80:
                     81: extern struct domain inetdomain;
                     82: extern struct protosw inetsw[];
                     83: u_char ip_protox[IPPROTO_MAX];
                     84: int    ipqmaxlen = IFQ_MAXLEN;
1.22      mycroft    85: struct in_ifaddrhead in_ifaddr;
1.13      mycroft    86: struct ifqueue ipintrq;
1.1       cgd        87:
                     88: /*
                     89:  * We need to save the IP options in case a protocol wants to respond
                     90:  * to an incoming packet over the same route if the packet got here
                     91:  * using IP source routing.  This allows connection establishment and
                     92:  * maintenance when the remote end is on a network that is not known
                     93:  * to us.
                     94:  */
                     95: int    ip_nhops = 0;
                     96: static struct ip_srcrt {
                     97:        struct  in_addr dst;                    /* final destination */
                     98:        char    nop;                            /* one NOP to align */
                     99:        char    srcopt[IPOPT_OFFSET + 1];       /* OPTVAL, OLEN and OFFSET */
                    100:        struct  in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
                    101: } ip_srcrt;
                    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;
1.25      cgd       124:        LIST_INIT(&ipq);
1.1       cgd       125:        ip_id = time.tv_sec & 0xffff;
                    126:        ipintrq.ifq_maxlen = ipqmaxlen;
1.22      mycroft   127:        TAILQ_INIT(&in_ifaddr);
1.1       cgd       128: }
                    129:
                    130: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    131: struct route ipforward_rt;
                    132:
                    133: /*
                    134:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    135:  * try to reassemble.  Process options.  Pass to next level.
                    136:  */
1.8       mycroft   137: void
1.1       cgd       138: ipintr()
                    139: {
                    140:        register struct ip *ip;
                    141:        register struct mbuf *m;
                    142:        register struct ipq *fp;
                    143:        register struct in_ifaddr *ia;
1.25      cgd       144:        struct ipqent *ipqe;
                    145:        int hlen, mff, s;
1.1       cgd       146:
                    147: next:
                    148:        /*
                    149:         * Get next datagram off input queue and get IP header
                    150:         * in first mbuf.
                    151:         */
                    152:        s = splimp();
                    153:        IF_DEQUEUE(&ipintrq, m);
                    154:        splx(s);
1.13      mycroft   155:        if (m == 0)
1.1       cgd       156:                return;
                    157: #ifdef DIAGNOSTIC
                    158:        if ((m->m_flags & M_PKTHDR) == 0)
                    159:                panic("ipintr no HDR");
                    160: #endif
                    161:        /*
                    162:         * If no IP addresses have been set yet but the interfaces
                    163:         * are receiving, can't do anything with incoming packets yet.
                    164:         */
1.22      mycroft   165:        if (in_ifaddr.tqh_first == 0)
1.1       cgd       166:                goto bad;
                    167:        ipstat.ips_total++;
                    168:        if (m->m_len < sizeof (struct ip) &&
                    169:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    170:                ipstat.ips_toosmall++;
                    171:                goto next;
                    172:        }
                    173:        ip = mtod(m, struct ip *);
1.13      mycroft   174:        if (ip->ip_v != IPVERSION) {
                    175:                ipstat.ips_badvers++;
                    176:                goto bad;
                    177:        }
1.1       cgd       178:        hlen = ip->ip_hl << 2;
                    179:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    180:                ipstat.ips_badhlen++;
                    181:                goto bad;
                    182:        }
                    183:        if (hlen > m->m_len) {
                    184:                if ((m = m_pullup(m, hlen)) == 0) {
                    185:                        ipstat.ips_badhlen++;
                    186:                        goto next;
                    187:                }
                    188:                ip = mtod(m, struct ip *);
                    189:        }
                    190:        if (ip->ip_sum = in_cksum(m, hlen)) {
                    191:                ipstat.ips_badsum++;
                    192:                goto bad;
                    193:        }
                    194:
                    195:        /*
                    196:         * Convert fields to host representation.
                    197:         */
                    198:        NTOHS(ip->ip_len);
                    199:        if (ip->ip_len < hlen) {
                    200:                ipstat.ips_badlen++;
                    201:                goto bad;
                    202:        }
                    203:        NTOHS(ip->ip_id);
                    204:        NTOHS(ip->ip_off);
                    205:
                    206:        /*
                    207:         * Check that the amount of data in the buffers
                    208:         * is as at least much as the IP header would have us expect.
                    209:         * Trim mbufs if longer than we expect.
                    210:         * Drop packet if shorter than we expect.
                    211:         */
                    212:        if (m->m_pkthdr.len < ip->ip_len) {
                    213:                ipstat.ips_tooshort++;
                    214:                goto bad;
                    215:        }
                    216:        if (m->m_pkthdr.len > ip->ip_len) {
                    217:                if (m->m_len == m->m_pkthdr.len) {
                    218:                        m->m_len = ip->ip_len;
                    219:                        m->m_pkthdr.len = ip->ip_len;
                    220:                } else
                    221:                        m_adj(m, ip->ip_len - m->m_pkthdr.len);
                    222:        }
                    223:
                    224:        /*
                    225:         * Process options and, if not destined for us,
                    226:         * ship it on.  ip_dooptions returns 1 when an
                    227:         * error was detected (causing an icmp message
                    228:         * to be sent and the original packet to be freed).
                    229:         */
                    230:        ip_nhops = 0;           /* for source routed packets */
                    231:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    232:                goto next;
                    233:
                    234:        /*
                    235:         * Check our list of addresses, to see if the packet is for us.
                    236:         */
1.22      mycroft   237:        for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
1.20      mycroft   238:                if (ip->ip_dst.s_addr == ia->ia_addr.sin_addr.s_addr)
1.1       cgd       239:                        goto ours;
                    240:                if (
                    241: #ifdef DIRECTED_BROADCAST
                    242:                    ia->ia_ifp == m->m_pkthdr.rcvif &&
                    243: #endif
                    244:                    (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.20      mycroft   245:                        if (ip->ip_dst.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
                    246:                            ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr ||
                    247:                            /*
                    248:                             * Look for all-0's host part (old broadcast addr),
                    249:                             * either for subnet or net.
                    250:                             */
                    251:                            ip->ip_dst.s_addr == ia->ia_subnet ||
1.18      mycroft   252:                            ip->ip_dst.s_addr == ia->ia_net)
1.1       cgd       253:                                goto ours;
                    254:                }
                    255:        }
1.18      mycroft   256:        if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4       hpeyerl   257:                struct in_multi *inm;
                    258: #ifdef MROUTING
                    259:                extern struct socket *ip_mrouter;
1.10      brezak    260:
                    261:                if (m->m_flags & M_EXT) {
                    262:                        if ((m = m_pullup(m, hlen)) == 0) {
                    263:                                ipstat.ips_toosmall++;
                    264:                                goto next;
                    265:                        }
                    266:                        ip = mtod(m, struct ip *);
                    267:                }
1.4       hpeyerl   268:
                    269:                if (ip_mrouter) {
                    270:                        /*
                    271:                         * If we are acting as a multicast router, all
                    272:                         * incoming multicast packets are passed to the
                    273:                         * kernel-level multicast forwarding function.
                    274:                         * The packet is returned (relatively) intact; if
                    275:                         * ip_mforward() returns a non-zero value, the packet
                    276:                         * must be discarded, else it may be accepted below.
                    277:                         *
                    278:                         * (The IP ident field is put in the same byte order
                    279:                         * as expected when ip_mforward() is called from
                    280:                         * ip_output().)
                    281:                         */
                    282:                        ip->ip_id = htons(ip->ip_id);
1.13      mycroft   283:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    284:                                ipstat.ips_cantforward++;
1.4       hpeyerl   285:                                m_freem(m);
                    286:                                goto next;
                    287:                        }
                    288:                        ip->ip_id = ntohs(ip->ip_id);
                    289:
                    290:                        /*
                    291:                         * The process-level routing demon needs to receive
                    292:                         * all multicast IGMP packets, whether or not this
                    293:                         * host belongs to their destination groups.
                    294:                         */
                    295:                        if (ip->ip_p == IPPROTO_IGMP)
                    296:                                goto ours;
1.13      mycroft   297:                        ipstat.ips_forward++;
1.4       hpeyerl   298:                }
                    299: #endif
                    300:                /*
                    301:                 * See if we belong to the destination multicast group on the
                    302:                 * arrival interface.
                    303:                 */
                    304:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    305:                if (inm == NULL) {
1.13      mycroft   306:                        ipstat.ips_cantforward++;
1.4       hpeyerl   307:                        m_freem(m);
                    308:                        goto next;
                    309:                }
                    310:                goto ours;
                    311:        }
1.19      mycroft   312:        if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
                    313:            ip->ip_dst.s_addr == INADDR_ANY)
1.1       cgd       314:                goto ours;
                    315:
                    316:        /*
                    317:         * Not for us; forward if possible and desirable.
                    318:         */
                    319:        if (ipforwarding == 0) {
                    320:                ipstat.ips_cantforward++;
                    321:                m_freem(m);
                    322:        } else
                    323:                ip_forward(m, 0);
                    324:        goto next;
                    325:
                    326: ours:
                    327:        /*
                    328:         * If offset or IP_MF are set, must reassemble.
                    329:         * Otherwise, nothing need be done.
                    330:         * (We could look in the reassembly queue to see
                    331:         * if the packet was previously fragmented,
                    332:         * but it's not worth the time; just let them time out.)
                    333:         */
                    334:        if (ip->ip_off &~ IP_DF) {
                    335:                if (m->m_flags & M_EXT) {               /* XXX */
                    336:                        if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
                    337:                                ipstat.ips_toosmall++;
                    338:                                goto next;
                    339:                        }
                    340:                        ip = mtod(m, struct ip *);
                    341:                }
                    342:                /*
                    343:                 * Look for queue of fragments
                    344:                 * of this datagram.
                    345:                 */
1.25      cgd       346:                for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1       cgd       347:                        if (ip->ip_id == fp->ipq_id &&
                    348:                            ip->ip_src.s_addr == fp->ipq_src.s_addr &&
                    349:                            ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
                    350:                            ip->ip_p == fp->ipq_p)
                    351:                                goto found;
                    352:                fp = 0;
                    353: found:
                    354:
                    355:                /*
                    356:                 * Adjust ip_len to not reflect header,
1.25      cgd       357:                 * set ipqe_mff if more fragments are expected,
1.1       cgd       358:                 * convert offset of this to bytes.
                    359:                 */
                    360:                ip->ip_len -= hlen;
1.25      cgd       361:                mff = (ip->ip_off & IP_MF) != 0;
                    362:                if (mff) {
1.16      cgd       363:                        /*
                    364:                         * Make sure that fragments have a data length
                    365:                         * that's a non-zero multiple of 8 bytes.
                    366:                         */
1.17      cgd       367:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16      cgd       368:                                ipstat.ips_badfrags++;
                    369:                                goto bad;
                    370:                        }
                    371:                }
1.1       cgd       372:                ip->ip_off <<= 3;
                    373:
                    374:                /*
                    375:                 * If datagram marked as having more fragments
                    376:                 * or if this is not the first fragment,
                    377:                 * attempt reassembly; if it succeeds, proceed.
                    378:                 */
1.25      cgd       379:                if (mff || ip->ip_off) {
1.1       cgd       380:                        ipstat.ips_fragments++;
1.25      cgd       381:                        MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent),
                    382:                            M_IPQ, M_NOWAIT);
                    383:                        if (ipqe == NULL) {
                    384:                                ipstat.ips_rcvmemdrop++;
                    385:                                goto bad;
                    386:                        }
                    387:                        ipqe->ipqe_mff = mff;
                    388:                        ipqe->ipqe_ip = ip;
                    389:                        ip = ip_reass(ipqe, fp);
1.1       cgd       390:                        if (ip == 0)
                    391:                                goto next;
1.13      mycroft   392:                        ipstat.ips_reassembled++;
1.1       cgd       393:                        m = dtom(ip);
                    394:                } else
                    395:                        if (fp)
                    396:                                ip_freef(fp);
                    397:        } else
                    398:                ip->ip_len -= hlen;
                    399:
                    400:        /*
                    401:         * Switch out to protocol's input routine.
                    402:         */
                    403:        ipstat.ips_delivered++;
                    404:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    405:        goto next;
                    406: bad:
                    407:        m_freem(m);
                    408:        goto next;
                    409: }
                    410:
                    411: /*
                    412:  * Take incoming datagram fragment and try to
                    413:  * reassemble it into whole datagram.  If a chain for
                    414:  * reassembly of this datagram already exists, then it
                    415:  * is given as fp; otherwise have to make a chain.
                    416:  */
                    417: struct ip *
1.25      cgd       418: ip_reass(ipqe, fp)
                    419:        register struct ipqent *ipqe;
1.1       cgd       420:        register struct ipq *fp;
                    421: {
1.25      cgd       422:        register struct mbuf *m = dtom(ipqe->ipqe_ip);
                    423:        register struct ipqent *nq, *p, *q;
                    424:        struct ip *ip;
1.1       cgd       425:        struct mbuf *t;
1.25      cgd       426:        int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1       cgd       427:        int i, next;
                    428:
                    429:        /*
                    430:         * Presence of header sizes in mbufs
                    431:         * would confuse code below.
                    432:         */
                    433:        m->m_data += hlen;
                    434:        m->m_len -= hlen;
                    435:
                    436:        /*
                    437:         * If first fragment to arrive, create a reassembly queue.
                    438:         */
                    439:        if (fp == 0) {
                    440:                if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
                    441:                        goto dropfrag;
                    442:                fp = mtod(t, struct ipq *);
1.25      cgd       443:                LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1       cgd       444:                fp->ipq_ttl = IPFRAGTTL;
1.25      cgd       445:                fp->ipq_p = ipqe->ipqe_ip->ip_p;
                    446:                fp->ipq_id = ipqe->ipqe_ip->ip_id;
                    447:                LIST_INIT(&fp->ipq_fragq);
                    448:                fp->ipq_src = ipqe->ipqe_ip->ip_src;
                    449:                fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
                    450:                p = NULL;
1.1       cgd       451:                goto insert;
                    452:        }
                    453:
                    454:        /*
                    455:         * Find a segment which begins after this one does.
                    456:         */
1.25      cgd       457:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    458:            p = q, q = q->ipqe_q.le_next)
                    459:                if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1       cgd       460:                        break;
                    461:
                    462:        /*
                    463:         * If there is a preceding segment, it may provide some of
                    464:         * our data already.  If so, drop the data from the incoming
                    465:         * segment.  If it provides all of our data, drop us.
                    466:         */
1.25      cgd       467:        if (p != NULL) {
                    468:                i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
                    469:                    ipqe->ipqe_ip->ip_off;
1.1       cgd       470:                if (i > 0) {
1.25      cgd       471:                        if (i >= ipqe->ipqe_ip->ip_len)
1.1       cgd       472:                                goto dropfrag;
1.25      cgd       473:                        m_adj(dtom(ipqe->ipqe_ip), i);
                    474:                        ipqe->ipqe_ip->ip_off += i;
                    475:                        ipqe->ipqe_ip->ip_len -= i;
1.1       cgd       476:                }
                    477:        }
                    478:
                    479:        /*
                    480:         * While we overlap succeeding segments trim them or,
                    481:         * if they are completely covered, dequeue them.
                    482:         */
1.25      cgd       483:        for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
                    484:            q->ipqe_ip->ip_off; q = nq) {
                    485:                i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
                    486:                    q->ipqe_ip->ip_off;
                    487:                if (i < q->ipqe_ip->ip_len) {
                    488:                        q->ipqe_ip->ip_len -= i;
                    489:                        q->ipqe_ip->ip_off += i;
                    490:                        m_adj(dtom(q->ipqe_ip), i);
1.1       cgd       491:                        break;
                    492:                }
1.25      cgd       493:                nq = q->ipqe_q.le_next;
                    494:                m_freem(dtom(q->ipqe_ip));
                    495:                LIST_REMOVE(q, ipqe_q);
                    496:                FREE(q, M_IPQ);
1.1       cgd       497:        }
                    498:
                    499: insert:
                    500:        /*
                    501:         * Stick new segment in its place;
                    502:         * check for complete reassembly.
                    503:         */
1.25      cgd       504:        if (p == NULL) {
                    505:                LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
                    506:        } else {
                    507:                LIST_INSERT_AFTER(p, ipqe, ipqe_q);
                    508:        }
1.1       cgd       509:        next = 0;
1.25      cgd       510:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    511:            p = q, q = q->ipqe_q.le_next) {
                    512:                if (q->ipqe_ip->ip_off != next)
1.1       cgd       513:                        return (0);
1.25      cgd       514:                next += q->ipqe_ip->ip_len;
1.1       cgd       515:        }
1.25      cgd       516:        if (p->ipqe_mff)
1.1       cgd       517:                return (0);
                    518:
                    519:        /*
                    520:         * Reassembly is complete; concatenate fragments.
                    521:         */
1.25      cgd       522:        q = fp->ipq_fragq.lh_first;
                    523:        ip = q->ipqe_ip;
                    524:        m = dtom(q->ipqe_ip);
1.1       cgd       525:        t = m->m_next;
                    526:        m->m_next = 0;
                    527:        m_cat(m, t);
1.25      cgd       528:        nq = q->ipqe_q.le_next;
                    529:        FREE(q, M_IPQ);
                    530:        for (q = nq; q != NULL; q = nq) {
                    531:                t = dtom(q->ipqe_ip);
                    532:                nq = q->ipqe_q.le_next;
                    533:                FREE(q, M_IPQ);
1.1       cgd       534:                m_cat(m, t);
                    535:        }
                    536:
                    537:        /*
                    538:         * Create header for new ip packet by
                    539:         * modifying header of first packet;
                    540:         * dequeue and discard fragment reassembly header.
                    541:         * Make header visible.
                    542:         */
                    543:        ip->ip_len = next;
1.25      cgd       544:        ip->ip_src = fp->ipq_src;
                    545:        ip->ip_dst = fp->ipq_dst;
                    546:        LIST_REMOVE(fp, ipq_q);
1.1       cgd       547:        (void) m_free(dtom(fp));
                    548:        m->m_len += (ip->ip_hl << 2);
                    549:        m->m_data -= (ip->ip_hl << 2);
                    550:        /* some debugging cruft by sklower, below, will go away soon */
                    551:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
                    552:                register int plen = 0;
                    553:                for (t = m; m; m = m->m_next)
                    554:                        plen += m->m_len;
                    555:                t->m_pkthdr.len = plen;
                    556:        }
1.25      cgd       557:        return (ip);
1.1       cgd       558:
                    559: dropfrag:
                    560:        ipstat.ips_fragdropped++;
                    561:        m_freem(m);
1.25      cgd       562:        FREE(ipqe, M_IPQ);
1.1       cgd       563:        return (0);
                    564: }
                    565:
                    566: /*
                    567:  * Free a fragment reassembly header and all
                    568:  * associated datagrams.
                    569:  */
1.8       mycroft   570: void
1.1       cgd       571: ip_freef(fp)
                    572:        struct ipq *fp;
                    573: {
1.25      cgd       574:        register struct ipqent *q, *p;
1.1       cgd       575:
1.25      cgd       576:        for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
                    577:                p = q->ipqe_q.le_next;
                    578:                m_freem(dtom(q->ipqe_ip));
                    579:                LIST_REMOVE(q, ipqe_q);
                    580:                FREE(q, M_IPQ);
1.1       cgd       581:        }
1.25      cgd       582:        LIST_REMOVE(fp, ipq_q);
1.1       cgd       583:        (void) m_free(dtom(fp));
                    584: }
                    585:
                    586: /*
                    587:  * IP timer processing;
                    588:  * if a timer expires on a reassembly
                    589:  * queue, discard it.
                    590:  */
1.8       mycroft   591: void
1.1       cgd       592: ip_slowtimo()
                    593: {
1.25      cgd       594:        register struct ipq *fp, *nfp;
1.24      mycroft   595:        int s = splsoftnet();
1.1       cgd       596:
1.25      cgd       597:        for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
                    598:                nfp = fp->ipq_q.le_next;
                    599:                if (--fp->ipq_ttl == 0) {
1.1       cgd       600:                        ipstat.ips_fragtimeout++;
1.25      cgd       601:                        ip_freef(fp);
1.1       cgd       602:                }
                    603:        }
                    604:        splx(s);
                    605: }
                    606:
                    607: /*
                    608:  * Drain off all datagram fragments.
                    609:  */
1.8       mycroft   610: void
1.1       cgd       611: ip_drain()
                    612: {
                    613:
1.25      cgd       614:        while (ipq.lh_first != NULL) {
1.1       cgd       615:                ipstat.ips_fragdropped++;
1.25      cgd       616:                ip_freef(ipq.lh_first);
1.1       cgd       617:        }
                    618: }
                    619:
                    620: /*
                    621:  * Do option processing on a datagram,
                    622:  * possibly discarding it if bad options are encountered,
                    623:  * or forwarding it if source-routed.
                    624:  * Returns 1 if packet has been forwarded/freed,
                    625:  * 0 if the packet should be processed further.
                    626:  */
1.8       mycroft   627: int
1.1       cgd       628: ip_dooptions(m)
                    629:        struct mbuf *m;
                    630: {
                    631:        register struct ip *ip = mtod(m, struct ip *);
                    632:        register u_char *cp;
                    633:        register struct ip_timestamp *ipt;
                    634:        register struct in_ifaddr *ia;
                    635:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13      mycroft   636:        struct in_addr *sin, dst;
1.1       cgd       637:        n_time ntime;
                    638:
1.13      mycroft   639:        dst = ip->ip_dst;
1.1       cgd       640:        cp = (u_char *)(ip + 1);
                    641:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    642:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    643:                opt = cp[IPOPT_OPTVAL];
                    644:                if (opt == IPOPT_EOL)
                    645:                        break;
                    646:                if (opt == IPOPT_NOP)
                    647:                        optlen = 1;
                    648:                else {
                    649:                        optlen = cp[IPOPT_OLEN];
                    650:                        if (optlen <= 0 || optlen > cnt) {
                    651:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    652:                                goto bad;
                    653:                        }
                    654:                }
                    655:                switch (opt) {
                    656:
                    657:                default:
                    658:                        break;
                    659:
                    660:                /*
                    661:                 * Source routing with record.
                    662:                 * Find interface with current destination address.
                    663:                 * If none on this machine then drop if strictly routed,
                    664:                 * or do nothing if loosely routed.
                    665:                 * Record interface address and bring up next address
                    666:                 * component.  If strictly routed make sure next
                    667:                 * address is on directly accessible net.
                    668:                 */
                    669:                case IPOPT_LSRR:
                    670:                case IPOPT_SSRR:
                    671:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    672:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    673:                                goto bad;
                    674:                        }
                    675:                        ipaddr.sin_addr = ip->ip_dst;
1.19      mycroft   676:                        ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1       cgd       677:                        if (ia == 0) {
                    678:                                if (opt == IPOPT_SSRR) {
                    679:                                        type = ICMP_UNREACH;
                    680:                                        code = ICMP_UNREACH_SRCFAIL;
                    681:                                        goto bad;
                    682:                                }
                    683:                                /*
                    684:                                 * Loose routing, and not at next destination
                    685:                                 * yet; nothing to do except forward.
                    686:                                 */
                    687:                                break;
                    688:                        }
                    689:                        off--;                  /* 0 origin */
                    690:                        if (off > optlen - sizeof(struct in_addr)) {
                    691:                                /*
                    692:                                 * End of source route.  Should be for us.
                    693:                                 */
                    694:                                save_rte(cp, ip->ip_src);
                    695:                                break;
                    696:                        }
                    697:                        /*
                    698:                         * locate outgoing interface
                    699:                         */
                    700:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    701:                            sizeof(ipaddr.sin_addr));
                    702:                        if (opt == IPOPT_SSRR) {
                    703: #define        INA     struct in_ifaddr *
                    704: #define        SA      struct sockaddr *
                    705:                            if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
1.13      mycroft   706:                                ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1.1       cgd       707:                        } else
                    708:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    709:                        if (ia == 0) {
                    710:                                type = ICMP_UNREACH;
                    711:                                code = ICMP_UNREACH_SRCFAIL;
                    712:                                goto bad;
                    713:                        }
                    714:                        ip->ip_dst = ipaddr.sin_addr;
1.20      mycroft   715:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       716:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    717:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft   718:                        /*
                    719:                         * Let ip_intr's mcast routing check handle mcast pkts
                    720:                         */
1.18      mycroft   721:                        forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1       cgd       722:                        break;
                    723:
                    724:                case IPOPT_RR:
                    725:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    726:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    727:                                goto bad;
                    728:                        }
                    729:                        /*
                    730:                         * If no space remains, ignore.
                    731:                         */
                    732:                        off--;                  /* 0 origin */
                    733:                        if (off > optlen - sizeof(struct in_addr))
                    734:                                break;
                    735:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    736:                            sizeof(ipaddr.sin_addr));
                    737:                        /*
                    738:                         * locate outgoing interface; if we're the destination,
                    739:                         * use the incoming interface (should be same).
                    740:                         */
                    741:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    742:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    743:                                type = ICMP_UNREACH;
                    744:                                code = ICMP_UNREACH_HOST;
                    745:                                goto bad;
                    746:                        }
1.20      mycroft   747:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       748:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    749:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    750:                        break;
                    751:
                    752:                case IPOPT_TS:
                    753:                        code = cp - (u_char *)ip;
                    754:                        ipt = (struct ip_timestamp *)cp;
                    755:                        if (ipt->ipt_len < 5)
                    756:                                goto bad;
1.15      cgd       757:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1       cgd       758:                                if (++ipt->ipt_oflw == 0)
                    759:                                        goto bad;
                    760:                                break;
                    761:                        }
                    762:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    763:                        switch (ipt->ipt_flg) {
                    764:
                    765:                        case IPOPT_TS_TSONLY:
                    766:                                break;
                    767:
                    768:                        case IPOPT_TS_TSANDADDR:
                    769:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    770:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    771:                                        goto bad;
1.13      mycroft   772:                                ipaddr.sin_addr = dst;
                    773:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
                    774:                                                            m->m_pkthdr.rcvif);
                    775:                                if (ia == 0)
                    776:                                        continue;
1.20      mycroft   777:                                bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       778:                                    (caddr_t)sin, sizeof(struct in_addr));
                    779:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    780:                                break;
                    781:
                    782:                        case IPOPT_TS_PRESPEC:
                    783:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    784:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    785:                                        goto bad;
                    786:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    787:                                    sizeof(struct in_addr));
                    788:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    789:                                        continue;
                    790:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    791:                                break;
                    792:
                    793:                        default:
                    794:                                goto bad;
                    795:                        }
                    796:                        ntime = iptime();
                    797:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    798:                            sizeof(n_time));
                    799:                        ipt->ipt_ptr += sizeof(n_time);
                    800:                }
                    801:        }
                    802:        if (forward) {
1.26    ! thorpej   803:                if (ip_forwsrcrt == 0) {
        !           804:                        type = ICMP_UNREACH;
        !           805:                        code = ICMP_UNREACH_SRCFAIL;
        !           806:                        goto bad;
        !           807:                }
1.1       cgd       808:                ip_forward(m, 1);
                    809:                return (1);
1.13      mycroft   810:        }
                    811:        return (0);
1.1       cgd       812: bad:
1.13      mycroft   813:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
                    814:        icmp_error(m, type, code, 0, 0);
                    815:        ipstat.ips_badoptions++;
1.1       cgd       816:        return (1);
                    817: }
                    818:
                    819: /*
                    820:  * Given address of next destination (final or next hop),
                    821:  * return internet address info of interface to be used to get there.
                    822:  */
                    823: struct in_ifaddr *
                    824: ip_rtaddr(dst)
                    825:         struct in_addr dst;
                    826: {
                    827:        register struct sockaddr_in *sin;
                    828:
1.19      mycroft   829:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd       830:
                    831:        if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
                    832:                if (ipforward_rt.ro_rt) {
                    833:                        RTFREE(ipforward_rt.ro_rt);
                    834:                        ipforward_rt.ro_rt = 0;
                    835:                }
                    836:                sin->sin_family = AF_INET;
                    837:                sin->sin_len = sizeof(*sin);
                    838:                sin->sin_addr = dst;
                    839:
                    840:                rtalloc(&ipforward_rt);
                    841:        }
                    842:        if (ipforward_rt.ro_rt == 0)
                    843:                return ((struct in_ifaddr *)0);
1.19      mycroft   844:        return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1       cgd       845: }
                    846:
                    847: /*
                    848:  * Save incoming source route for use in replies,
                    849:  * to be picked up later by ip_srcroute if the receiver is interested.
                    850:  */
1.13      mycroft   851: void
1.1       cgd       852: save_rte(option, dst)
                    853:        u_char *option;
                    854:        struct in_addr dst;
                    855: {
                    856:        unsigned olen;
                    857:
                    858:        olen = option[IPOPT_OLEN];
                    859: #ifdef DIAGNOSTIC
                    860:        if (ipprintfs)
                    861:                printf("save_rte: olen %d\n", olen);
                    862: #endif
                    863:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    864:                return;
                    865:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    866:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    867:        ip_srcrt.dst = dst;
                    868: }
                    869:
                    870: /*
                    871:  * Retrieve incoming source route for use in replies,
                    872:  * in the same form used by setsockopt.
                    873:  * The first hop is placed before the options, will be removed later.
                    874:  */
                    875: struct mbuf *
                    876: ip_srcroute()
                    877: {
                    878:        register struct in_addr *p, *q;
                    879:        register struct mbuf *m;
                    880:
                    881:        if (ip_nhops == 0)
                    882:                return ((struct mbuf *)0);
                    883:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    884:        if (m == 0)
                    885:                return ((struct mbuf *)0);
                    886:
1.13      mycroft   887: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       888:
                    889:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    890:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    891:            OPTSIZ;
                    892: #ifdef DIAGNOSTIC
                    893:        if (ipprintfs)
                    894:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
                    895: #endif
                    896:
                    897:        /*
                    898:         * First save first hop for return route
                    899:         */
                    900:        p = &ip_srcrt.route[ip_nhops - 1];
                    901:        *(mtod(m, struct in_addr *)) = *p--;
                    902: #ifdef DIAGNOSTIC
                    903:        if (ipprintfs)
                    904:                printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr));
                    905: #endif
                    906:
                    907:        /*
                    908:         * Copy option fields and padding (nop) to mbuf.
                    909:         */
                    910:        ip_srcrt.nop = IPOPT_NOP;
                    911:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    912:        bcopy((caddr_t)&ip_srcrt.nop,
                    913:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    914:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    915:            sizeof(struct in_addr) + OPTSIZ);
                    916: #undef OPTSIZ
                    917:        /*
                    918:         * Record return path as an IP source route,
                    919:         * reversing the path (pointers are now aligned).
                    920:         */
                    921:        while (p >= ip_srcrt.route) {
                    922: #ifdef DIAGNOSTIC
                    923:                if (ipprintfs)
                    924:                        printf(" %lx", ntohl(q->s_addr));
                    925: #endif
                    926:                *q++ = *p--;
                    927:        }
                    928:        /*
                    929:         * Last hop goes to final destination.
                    930:         */
                    931:        *q = ip_srcrt.dst;
                    932: #ifdef DIAGNOSTIC
                    933:        if (ipprintfs)
                    934:                printf(" %lx\n", ntohl(q->s_addr));
                    935: #endif
                    936:        return (m);
                    937: }
                    938:
                    939: /*
                    940:  * Strip out IP options, at higher
                    941:  * level protocol in the kernel.
                    942:  * Second argument is buffer to which options
                    943:  * will be moved, and return value is their length.
                    944:  * XXX should be deleted; last arg currently ignored.
                    945:  */
1.8       mycroft   946: void
1.1       cgd       947: ip_stripoptions(m, mopt)
                    948:        register struct mbuf *m;
                    949:        struct mbuf *mopt;
                    950: {
                    951:        register int i;
                    952:        struct ip *ip = mtod(m, struct ip *);
                    953:        register caddr_t opts;
                    954:        int olen;
                    955:
                    956:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                    957:        opts = (caddr_t)(ip + 1);
                    958:        i = m->m_len - (sizeof (struct ip) + olen);
                    959:        bcopy(opts  + olen, opts, (unsigned)i);
                    960:        m->m_len -= olen;
                    961:        if (m->m_flags & M_PKTHDR)
                    962:                m->m_pkthdr.len -= olen;
                    963:        ip->ip_hl = sizeof(struct ip) >> 2;
                    964: }
                    965:
1.23      mycroft   966: int inetctlerrmap[PRC_NCMDS] = {
1.1       cgd       967:        0,              0,              0,              0,
                    968:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                    969:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                    970:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                    971:        0,              0,              0,              0,
                    972:        ENOPROTOOPT
                    973: };
                    974:
                    975: /*
                    976:  * Forward a packet.  If some error occurs return the sender
                    977:  * an icmp packet.  Note we can't always generate a meaningful
                    978:  * icmp message because icmp doesn't have a large enough repertoire
                    979:  * of codes and types.
                    980:  *
                    981:  * If not forwarding, just drop the packet.  This could be confusing
                    982:  * if ipforwarding was zero but some routing protocol was advancing
                    983:  * us as a gateway to somewhere.  However, we must let the routing
                    984:  * protocol deal with that.
                    985:  *
                    986:  * The srcrt parameter indicates whether the packet is being forwarded
                    987:  * via a source route.
                    988:  */
1.13      mycroft   989: void
1.1       cgd       990: ip_forward(m, srcrt)
                    991:        struct mbuf *m;
                    992:        int srcrt;
                    993: {
                    994:        register struct ip *ip = mtod(m, struct ip *);
                    995:        register struct sockaddr_in *sin;
                    996:        register struct rtentry *rt;
                    997:        int error, type = 0, code;
                    998:        struct mbuf *mcopy;
1.13      mycroft   999:        n_long dest;
                   1000:        struct ifnet *destifp;
1.1       cgd      1001:
1.13      mycroft  1002:        dest = 0;
1.1       cgd      1003: #ifdef DIAGNOSTIC
                   1004:        if (ipprintfs)
                   1005:                printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
                   1006:                        ip->ip_dst, ip->ip_ttl);
                   1007: #endif
                   1008:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1009:                ipstat.ips_cantforward++;
                   1010:                m_freem(m);
                   1011:                return;
                   1012:        }
                   1013:        HTONS(ip->ip_id);
                   1014:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1015:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1016:                return;
                   1017:        }
                   1018:        ip->ip_ttl -= IPTTLDEC;
                   1019:
1.19      mycroft  1020:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1021:        if ((rt = ipforward_rt.ro_rt) == 0 ||
                   1022:            ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
                   1023:                if (ipforward_rt.ro_rt) {
                   1024:                        RTFREE(ipforward_rt.ro_rt);
                   1025:                        ipforward_rt.ro_rt = 0;
                   1026:                }
                   1027:                sin->sin_family = AF_INET;
                   1028:                sin->sin_len = sizeof(*sin);
                   1029:                sin->sin_addr = ip->ip_dst;
                   1030:
                   1031:                rtalloc(&ipforward_rt);
                   1032:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1033:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1034:                        return;
                   1035:                }
                   1036:                rt = ipforward_rt.ro_rt;
                   1037:        }
                   1038:
                   1039:        /*
                   1040:         * Save at most 64 bytes of the packet in case
                   1041:         * we need to generate an ICMP message to the src.
                   1042:         */
                   1043:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
                   1044:
                   1045:        /*
                   1046:         * If forwarding packet using same interface that it came in on,
                   1047:         * perhaps should send a redirect to sender to shortcut a hop.
                   1048:         * Only send redirect if source is sending directly to us,
                   1049:         * and if packet was not source routed (or has any options).
                   1050:         * Also, don't send redirect if forwarding using a default route
                   1051:         * or a route modified by a redirect.
                   1052:         */
                   1053:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1054:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
                   1055:            satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
                   1056:            ipsendredirects && !srcrt) {
1.19      mycroft  1057:                if (rt->rt_ifa &&
                   1058:                    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
                   1059:                    ifatoia(rt->rt_ifa)->ia_subnet) {
1.1       cgd      1060:                    if (rt->rt_flags & RTF_GATEWAY)
1.13      mycroft  1061:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1062:                    else
1.13      mycroft  1063:                        dest = ip->ip_dst.s_addr;
                   1064:                    /* Router requirements says to only send host redirects */
1.1       cgd      1065:                    type = ICMP_REDIRECT;
1.13      mycroft  1066:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1067: #ifdef DIAGNOSTIC
                   1068:                    if (ipprintfs)
1.15      cgd      1069:                        printf("redirect (%d) to %lx\n", code, (u_int32_t)dest);
1.1       cgd      1070: #endif
                   1071:                }
                   1072:        }
                   1073:
1.13      mycroft  1074:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt, IP_FORWARDING
1.9       mycroft  1075: #ifdef DIRECTED_BROADCAST
1.13      mycroft  1076:                            | IP_ALLOWBROADCAST
1.9       mycroft  1077: #endif
1.13      mycroft  1078:                                                , 0);
1.1       cgd      1079:        if (error)
                   1080:                ipstat.ips_cantforward++;
                   1081:        else {
                   1082:                ipstat.ips_forward++;
                   1083:                if (type)
                   1084:                        ipstat.ips_redirectsent++;
                   1085:                else {
                   1086:                        if (mcopy)
                   1087:                                m_freem(mcopy);
                   1088:                        return;
                   1089:                }
                   1090:        }
                   1091:        if (mcopy == NULL)
                   1092:                return;
1.13      mycroft  1093:        destifp = NULL;
                   1094:
1.1       cgd      1095:        switch (error) {
                   1096:
                   1097:        case 0:                         /* forwarded, but need redirect */
                   1098:                /* type, code set above */
                   1099:                break;
                   1100:
                   1101:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1102:        case EHOSTUNREACH:
                   1103:        case ENETDOWN:
                   1104:        case EHOSTDOWN:
                   1105:        default:
                   1106:                type = ICMP_UNREACH;
                   1107:                code = ICMP_UNREACH_HOST;
                   1108:                break;
                   1109:
                   1110:        case EMSGSIZE:
                   1111:                type = ICMP_UNREACH;
                   1112:                code = ICMP_UNREACH_NEEDFRAG;
1.13      mycroft  1113:                if (ipforward_rt.ro_rt)
                   1114:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1115:                ipstat.ips_cantfrag++;
                   1116:                break;
                   1117:
                   1118:        case ENOBUFS:
                   1119:                type = ICMP_SOURCEQUENCH;
                   1120:                code = 0;
                   1121:                break;
                   1122:        }
1.13      mycroft  1123:        icmp_error(mcopy, type, code, dest, destifp);
                   1124: }
                   1125:
                   1126: int
                   1127: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1128:        int *name;
                   1129:        u_int namelen;
                   1130:        void *oldp;
                   1131:        size_t *oldlenp;
                   1132:        void *newp;
                   1133:        size_t newlen;
                   1134: {
1.26    ! thorpej  1135:        int temp;
        !          1136:
1.13      mycroft  1137:        /* All sysctl names at this level are terminal. */
                   1138:        if (namelen != 1)
                   1139:                return (ENOTDIR);
                   1140:
                   1141:        switch (name[0]) {
                   1142:        case IPCTL_FORWARDING:
                   1143:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
                   1144:        case IPCTL_SENDREDIRECTS:
                   1145:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1146:                        &ipsendredirects));
                   1147:        case IPCTL_DEFTTL:
                   1148:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
                   1149: #ifdef notyet
                   1150:        case IPCTL_DEFMTU:
                   1151:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
                   1152: #endif
1.26    ! thorpej  1153:        case IPCTL_FORWSRCRT:
        !          1154:                /*
        !          1155:                 * Don't allow this to change in a secure environment.
        !          1156:                 */
        !          1157:                if (securelevel > 0)
        !          1158:                        return (EPERM);
        !          1159:                return (sysctl_int(oldp, oldlenp, newp, newlen,
        !          1160:                    &ip_forwsrcrt));
1.13      mycroft  1161:        default:
                   1162:                return (EOPNOTSUPP);
                   1163:        }
                   1164:        /* NOTREACHED */
1.1       cgd      1165: }

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