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Annotation of src/sys/netinet/ip_input.c, Revision 1.16

1.16    ! cgd         1: /*     $NetBSD: ip_input.c,v 1.15 1995/04/13 06:33:21 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
                     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;
                     81: struct in_ifaddr *in_ifaddr;                   /* first inet address */
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:
                     99: #ifdef GATEWAY
                    100: extern int if_index;
1.15      cgd       101: u_int32_t *ip_ifmatrix;
1.1       cgd       102: #endif
                    103:
1.13      mycroft   104: static void save_rte __P((u_char *, struct in_addr));
1.1       cgd       105: /*
                    106:  * IP initialization: fill in IP protocol switch table.
                    107:  * All protocols not implemented in kernel go to raw IP protocol handler.
                    108:  */
1.8       mycroft   109: void
1.1       cgd       110: ip_init()
                    111: {
                    112:        register struct protosw *pr;
                    113:        register int i;
                    114:
                    115:        pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
                    116:        if (pr == 0)
                    117:                panic("ip_init");
                    118:        for (i = 0; i < IPPROTO_MAX; i++)
                    119:                ip_protox[i] = pr - inetsw;
                    120:        for (pr = inetdomain.dom_protosw;
                    121:            pr < inetdomain.dom_protoswNPROTOSW; pr++)
                    122:                if (pr->pr_domain->dom_family == PF_INET &&
                    123:                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
                    124:                        ip_protox[pr->pr_protocol] = pr - inetsw;
                    125:        ipq.next = ipq.prev = &ipq;
                    126:        ip_id = time.tv_sec & 0xffff;
                    127:        ipintrq.ifq_maxlen = ipqmaxlen;
                    128: #ifdef GATEWAY
1.15      cgd       129:        i = (if_index + 1) * (if_index + 1) * sizeof (u_int32_t);
                    130:        ip_ifmatrix = (u_int32_t *) malloc(i, M_RTABLE, M_WAITOK);
1.13      mycroft   131:        bzero((char *)ip_ifmatrix, i);
1.1       cgd       132: #endif
                    133: }
                    134:
                    135: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    136: struct route ipforward_rt;
                    137:
                    138: /*
                    139:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    140:  * try to reassemble.  Process options.  Pass to next level.
                    141:  */
1.8       mycroft   142: void
1.1       cgd       143: ipintr()
                    144: {
                    145:        register struct ip *ip;
                    146:        register struct mbuf *m;
                    147:        register struct ipq *fp;
                    148:        register struct in_ifaddr *ia;
                    149:        int hlen, s;
                    150:
                    151: next:
                    152:        /*
                    153:         * Get next datagram off input queue and get IP header
                    154:         * in first mbuf.
                    155:         */
                    156:        s = splimp();
                    157:        IF_DEQUEUE(&ipintrq, m);
                    158:        splx(s);
1.13      mycroft   159:        if (m == 0)
1.1       cgd       160:                return;
                    161: #ifdef DIAGNOSTIC
                    162:        if ((m->m_flags & M_PKTHDR) == 0)
                    163:                panic("ipintr no HDR");
                    164: #endif
                    165:        /*
                    166:         * If no IP addresses have been set yet but the interfaces
                    167:         * are receiving, can't do anything with incoming packets yet.
                    168:         */
                    169:        if (in_ifaddr == NULL)
                    170:                goto bad;
                    171:        ipstat.ips_total++;
                    172:        if (m->m_len < sizeof (struct ip) &&
                    173:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    174:                ipstat.ips_toosmall++;
                    175:                goto next;
                    176:        }
                    177:        ip = mtod(m, struct ip *);
1.13      mycroft   178:        if (ip->ip_v != IPVERSION) {
                    179:                ipstat.ips_badvers++;
                    180:                goto bad;
                    181:        }
1.1       cgd       182:        hlen = ip->ip_hl << 2;
                    183:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    184:                ipstat.ips_badhlen++;
                    185:                goto bad;
                    186:        }
                    187:        if (hlen > m->m_len) {
                    188:                if ((m = m_pullup(m, hlen)) == 0) {
                    189:                        ipstat.ips_badhlen++;
                    190:                        goto next;
                    191:                }
                    192:                ip = mtod(m, struct ip *);
                    193:        }
                    194:        if (ip->ip_sum = in_cksum(m, hlen)) {
                    195:                ipstat.ips_badsum++;
                    196:                goto bad;
                    197:        }
                    198:
                    199:        /*
                    200:         * Convert fields to host representation.
                    201:         */
                    202:        NTOHS(ip->ip_len);
                    203:        if (ip->ip_len < hlen) {
                    204:                ipstat.ips_badlen++;
                    205:                goto bad;
                    206:        }
                    207:        NTOHS(ip->ip_id);
                    208:        NTOHS(ip->ip_off);
                    209:
                    210:        /*
                    211:         * Check that the amount of data in the buffers
                    212:         * is as at least much as the IP header would have us expect.
                    213:         * Trim mbufs if longer than we expect.
                    214:         * Drop packet if shorter than we expect.
                    215:         */
                    216:        if (m->m_pkthdr.len < ip->ip_len) {
                    217:                ipstat.ips_tooshort++;
                    218:                goto bad;
                    219:        }
                    220:        if (m->m_pkthdr.len > ip->ip_len) {
                    221:                if (m->m_len == m->m_pkthdr.len) {
                    222:                        m->m_len = ip->ip_len;
                    223:                        m->m_pkthdr.len = ip->ip_len;
                    224:                } else
                    225:                        m_adj(m, ip->ip_len - m->m_pkthdr.len);
                    226:        }
                    227:
                    228:        /*
                    229:         * Process options and, if not destined for us,
                    230:         * ship it on.  ip_dooptions returns 1 when an
                    231:         * error was detected (causing an icmp message
                    232:         * to be sent and the original packet to be freed).
                    233:         */
                    234:        ip_nhops = 0;           /* for source routed packets */
                    235:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    236:                goto next;
                    237:
                    238:        /*
                    239:         * Check our list of addresses, to see if the packet is for us.
                    240:         */
                    241:        for (ia = in_ifaddr; ia; ia = ia->ia_next) {
                    242: #define        satosin(sa)     ((struct sockaddr_in *)(sa))
                    243:
                    244:                if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr)
                    245:                        goto ours;
                    246:                if (
                    247: #ifdef DIRECTED_BROADCAST
                    248:                    ia->ia_ifp == m->m_pkthdr.rcvif &&
                    249: #endif
                    250:                    (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.15      cgd       251:                        u_int32_t t;
1.1       cgd       252:
                    253:                        if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
                    254:                            ip->ip_dst.s_addr)
                    255:                                goto ours;
                    256:                        if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr)
                    257:                                goto ours;
                    258:                        /*
                    259:                         * Look for all-0's host part (old broadcast addr),
                    260:                         * either for subnet or net.
                    261:                         */
                    262:                        t = ntohl(ip->ip_dst.s_addr);
                    263:                        if (t == ia->ia_subnet)
                    264:                                goto ours;
                    265:                        if (t == ia->ia_net)
                    266:                                goto ours;
                    267:                }
                    268:        }
1.4       hpeyerl   269:        if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
                    270:                struct in_multi *inm;
                    271: #ifdef MROUTING
                    272:                extern struct socket *ip_mrouter;
1.10      brezak    273:
                    274:                if (m->m_flags & M_EXT) {
                    275:                        if ((m = m_pullup(m, hlen)) == 0) {
                    276:                                ipstat.ips_toosmall++;
                    277:                                goto next;
                    278:                        }
                    279:                        ip = mtod(m, struct ip *);
                    280:                }
1.4       hpeyerl   281:
                    282:                if (ip_mrouter) {
                    283:                        /*
                    284:                         * If we are acting as a multicast router, all
                    285:                         * incoming multicast packets are passed to the
                    286:                         * kernel-level multicast forwarding function.
                    287:                         * The packet is returned (relatively) intact; if
                    288:                         * ip_mforward() returns a non-zero value, the packet
                    289:                         * must be discarded, else it may be accepted below.
                    290:                         *
                    291:                         * (The IP ident field is put in the same byte order
                    292:                         * as expected when ip_mforward() is called from
                    293:                         * ip_output().)
                    294:                         */
                    295:                        ip->ip_id = htons(ip->ip_id);
1.13      mycroft   296:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    297:                                ipstat.ips_cantforward++;
1.4       hpeyerl   298:                                m_freem(m);
                    299:                                goto next;
                    300:                        }
                    301:                        ip->ip_id = ntohs(ip->ip_id);
                    302:
                    303:                        /*
                    304:                         * The process-level routing demon needs to receive
                    305:                         * all multicast IGMP packets, whether or not this
                    306:                         * host belongs to their destination groups.
                    307:                         */
                    308:                        if (ip->ip_p == IPPROTO_IGMP)
                    309:                                goto ours;
1.13      mycroft   310:                        ipstat.ips_forward++;
1.4       hpeyerl   311:                }
                    312: #endif
                    313:                /*
                    314:                 * See if we belong to the destination multicast group on the
                    315:                 * arrival interface.
                    316:                 */
                    317:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    318:                if (inm == NULL) {
1.13      mycroft   319:                        ipstat.ips_cantforward++;
1.4       hpeyerl   320:                        m_freem(m);
                    321:                        goto next;
                    322:                }
                    323:                goto ours;
                    324:        }
1.15      cgd       325:        if (ip->ip_dst.s_addr == (u_int32_t)INADDR_BROADCAST)
1.1       cgd       326:                goto ours;
                    327:        if (ip->ip_dst.s_addr == INADDR_ANY)
                    328:                goto ours;
                    329:
                    330:        /*
                    331:         * Not for us; forward if possible and desirable.
                    332:         */
                    333:        if (ipforwarding == 0) {
                    334:                ipstat.ips_cantforward++;
                    335:                m_freem(m);
                    336:        } else
                    337:                ip_forward(m, 0);
                    338:        goto next;
                    339:
                    340: ours:
                    341:        /*
                    342:         * If offset or IP_MF are set, must reassemble.
                    343:         * Otherwise, nothing need be done.
                    344:         * (We could look in the reassembly queue to see
                    345:         * if the packet was previously fragmented,
                    346:         * but it's not worth the time; just let them time out.)
                    347:         */
                    348:        if (ip->ip_off &~ IP_DF) {
                    349:                if (m->m_flags & M_EXT) {               /* XXX */
                    350:                        if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
                    351:                                ipstat.ips_toosmall++;
                    352:                                goto next;
                    353:                        }
                    354:                        ip = mtod(m, struct ip *);
                    355:                }
                    356:                /*
                    357:                 * Look for queue of fragments
                    358:                 * of this datagram.
                    359:                 */
                    360:                for (fp = ipq.next; fp != &ipq; fp = fp->next)
                    361:                        if (ip->ip_id == fp->ipq_id &&
                    362:                            ip->ip_src.s_addr == fp->ipq_src.s_addr &&
                    363:                            ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
                    364:                            ip->ip_p == fp->ipq_p)
                    365:                                goto found;
                    366:                fp = 0;
                    367: found:
                    368:
                    369:                /*
                    370:                 * Adjust ip_len to not reflect header,
                    371:                 * set ip_mff if more fragments are expected,
                    372:                 * convert offset of this to bytes.
                    373:                 */
                    374:                ip->ip_len -= hlen;
1.13      mycroft   375:                ((struct ipasfrag *)ip)->ipf_mff &= ~1;
1.16    ! cgd       376:                if (ip->ip_off & IP_MF) {
        !           377:                        /*
        !           378:                         * Make sure that fragments have a data length
        !           379:                         * that's a non-zero multiple of 8 bytes.
        !           380:                         */
        !           381:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0)
        !           382:                                ipstat.ips_badfrags++;
        !           383:                                goto bad;
        !           384:                        }
1.13      mycroft   385:                        ((struct ipasfrag *)ip)->ipf_mff |= 1;
1.16    ! cgd       386:                }
1.1       cgd       387:                ip->ip_off <<= 3;
                    388:
                    389:                /*
                    390:                 * If datagram marked as having more fragments
                    391:                 * or if this is not the first fragment,
                    392:                 * attempt reassembly; if it succeeds, proceed.
                    393:                 */
1.13      mycroft   394:                if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) {
1.1       cgd       395:                        ipstat.ips_fragments++;
                    396:                        ip = ip_reass((struct ipasfrag *)ip, fp);
                    397:                        if (ip == 0)
                    398:                                goto next;
1.13      mycroft   399:                        ipstat.ips_reassembled++;
1.1       cgd       400:                        m = dtom(ip);
                    401:                } else
                    402:                        if (fp)
                    403:                                ip_freef(fp);
                    404:        } else
                    405:                ip->ip_len -= hlen;
                    406:
                    407:        /*
                    408:         * Switch out to protocol's input routine.
                    409:         */
                    410:        ipstat.ips_delivered++;
                    411:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    412:        goto next;
                    413: bad:
                    414:        m_freem(m);
                    415:        goto next;
                    416: }
                    417:
                    418: /*
                    419:  * Take incoming datagram fragment and try to
                    420:  * reassemble it into whole datagram.  If a chain for
                    421:  * reassembly of this datagram already exists, then it
                    422:  * is given as fp; otherwise have to make a chain.
                    423:  */
                    424: struct ip *
                    425: ip_reass(ip, fp)
                    426:        register struct ipasfrag *ip;
                    427:        register struct ipq *fp;
                    428: {
                    429:        register struct mbuf *m = dtom(ip);
                    430:        register struct ipasfrag *q;
                    431:        struct mbuf *t;
                    432:        int hlen = ip->ip_hl << 2;
                    433:        int i, next;
                    434:
                    435:        /*
                    436:         * Presence of header sizes in mbufs
                    437:         * would confuse code below.
                    438:         */
                    439:        m->m_data += hlen;
                    440:        m->m_len -= hlen;
                    441:
                    442:        /*
                    443:         * If first fragment to arrive, create a reassembly queue.
                    444:         */
                    445:        if (fp == 0) {
                    446:                if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
                    447:                        goto dropfrag;
                    448:                fp = mtod(t, struct ipq *);
                    449:                insque(fp, &ipq);
                    450:                fp->ipq_ttl = IPFRAGTTL;
                    451:                fp->ipq_p = ip->ip_p;
                    452:                fp->ipq_id = ip->ip_id;
                    453:                fp->ipq_next = fp->ipq_prev = (struct ipasfrag *)fp;
                    454:                fp->ipq_src = ((struct ip *)ip)->ip_src;
                    455:                fp->ipq_dst = ((struct ip *)ip)->ip_dst;
                    456:                q = (struct ipasfrag *)fp;
                    457:                goto insert;
                    458:        }
                    459:
                    460:        /*
                    461:         * Find a segment which begins after this one does.
                    462:         */
                    463:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next)
                    464:                if (q->ip_off > ip->ip_off)
                    465:                        break;
                    466:
                    467:        /*
                    468:         * If there is a preceding segment, it may provide some of
                    469:         * our data already.  If so, drop the data from the incoming
                    470:         * segment.  If it provides all of our data, drop us.
                    471:         */
                    472:        if (q->ipf_prev != (struct ipasfrag *)fp) {
                    473:                i = q->ipf_prev->ip_off + q->ipf_prev->ip_len - ip->ip_off;
                    474:                if (i > 0) {
                    475:                        if (i >= ip->ip_len)
                    476:                                goto dropfrag;
                    477:                        m_adj(dtom(ip), i);
                    478:                        ip->ip_off += i;
                    479:                        ip->ip_len -= i;
                    480:                }
                    481:        }
                    482:
                    483:        /*
                    484:         * While we overlap succeeding segments trim them or,
                    485:         * if they are completely covered, dequeue them.
                    486:         */
                    487:        while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) {
                    488:                i = (ip->ip_off + ip->ip_len) - q->ip_off;
                    489:                if (i < q->ip_len) {
                    490:                        q->ip_len -= i;
                    491:                        q->ip_off += i;
                    492:                        m_adj(dtom(q), i);
                    493:                        break;
                    494:                }
                    495:                q = q->ipf_next;
                    496:                m_freem(dtom(q->ipf_prev));
                    497:                ip_deq(q->ipf_prev);
                    498:        }
                    499:
                    500: insert:
                    501:        /*
                    502:         * Stick new segment in its place;
                    503:         * check for complete reassembly.
                    504:         */
                    505:        ip_enq(ip, q->ipf_prev);
                    506:        next = 0;
                    507:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) {
                    508:                if (q->ip_off != next)
                    509:                        return (0);
                    510:                next += q->ip_len;
                    511:        }
1.13      mycroft   512:        if (q->ipf_prev->ipf_mff & 1)
1.1       cgd       513:                return (0);
                    514:
                    515:        /*
                    516:         * Reassembly is complete; concatenate fragments.
                    517:         */
                    518:        q = fp->ipq_next;
                    519:        m = dtom(q);
                    520:        t = m->m_next;
                    521:        m->m_next = 0;
                    522:        m_cat(m, t);
                    523:        q = q->ipf_next;
                    524:        while (q != (struct ipasfrag *)fp) {
                    525:                t = dtom(q);
                    526:                q = q->ipf_next;
                    527:                m_cat(m, t);
                    528:        }
                    529:
                    530:        /*
                    531:         * Create header for new ip packet by
                    532:         * modifying header of first packet;
                    533:         * dequeue and discard fragment reassembly header.
                    534:         * Make header visible.
                    535:         */
                    536:        ip = fp->ipq_next;
                    537:        ip->ip_len = next;
1.13      mycroft   538:        ip->ipf_mff &= ~1;
1.1       cgd       539:        ((struct ip *)ip)->ip_src = fp->ipq_src;
                    540:        ((struct ip *)ip)->ip_dst = fp->ipq_dst;
                    541:        remque(fp);
                    542:        (void) m_free(dtom(fp));
                    543:        m = dtom(ip);
                    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:        }
                    553:        return ((struct ip *)ip);
                    554:
                    555: dropfrag:
                    556:        ipstat.ips_fragdropped++;
                    557:        m_freem(m);
                    558:        return (0);
                    559: }
                    560:
                    561: /*
                    562:  * Free a fragment reassembly header and all
                    563:  * associated datagrams.
                    564:  */
1.8       mycroft   565: void
1.1       cgd       566: ip_freef(fp)
                    567:        struct ipq *fp;
                    568: {
                    569:        register struct ipasfrag *q, *p;
                    570:
                    571:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = p) {
                    572:                p = q->ipf_next;
                    573:                ip_deq(q);
                    574:                m_freem(dtom(q));
                    575:        }
                    576:        remque(fp);
                    577:        (void) m_free(dtom(fp));
                    578: }
                    579:
                    580: /*
                    581:  * Put an ip fragment on a reassembly chain.
                    582:  * Like insque, but pointers in middle of structure.
                    583:  */
1.8       mycroft   584: void
1.1       cgd       585: ip_enq(p, prev)
                    586:        register struct ipasfrag *p, *prev;
                    587: {
                    588:
                    589:        p->ipf_prev = prev;
                    590:        p->ipf_next = prev->ipf_next;
                    591:        prev->ipf_next->ipf_prev = p;
                    592:        prev->ipf_next = p;
                    593: }
                    594:
                    595: /*
                    596:  * To ip_enq as remque is to insque.
                    597:  */
1.8       mycroft   598: void
1.1       cgd       599: ip_deq(p)
                    600:        register struct ipasfrag *p;
                    601: {
                    602:
                    603:        p->ipf_prev->ipf_next = p->ipf_next;
                    604:        p->ipf_next->ipf_prev = p->ipf_prev;
                    605: }
                    606:
                    607: /*
                    608:  * IP timer processing;
                    609:  * if a timer expires on a reassembly
                    610:  * queue, discard it.
                    611:  */
1.8       mycroft   612: void
1.1       cgd       613: ip_slowtimo()
                    614: {
                    615:        register struct ipq *fp;
                    616:        int s = splnet();
                    617:
                    618:        fp = ipq.next;
                    619:        if (fp == 0) {
                    620:                splx(s);
                    621:                return;
                    622:        }
                    623:        while (fp != &ipq) {
                    624:                --fp->ipq_ttl;
                    625:                fp = fp->next;
                    626:                if (fp->prev->ipq_ttl == 0) {
                    627:                        ipstat.ips_fragtimeout++;
                    628:                        ip_freef(fp->prev);
                    629:                }
                    630:        }
                    631:        splx(s);
                    632: }
                    633:
                    634: /*
                    635:  * Drain off all datagram fragments.
                    636:  */
1.8       mycroft   637: void
1.1       cgd       638: ip_drain()
                    639: {
                    640:
                    641:        while (ipq.next != &ipq) {
                    642:                ipstat.ips_fragdropped++;
                    643:                ip_freef(ipq.next);
                    644:        }
                    645: }
                    646:
                    647: /*
                    648:  * Do option processing on a datagram,
                    649:  * possibly discarding it if bad options are encountered,
                    650:  * or forwarding it if source-routed.
                    651:  * Returns 1 if packet has been forwarded/freed,
                    652:  * 0 if the packet should be processed further.
                    653:  */
1.8       mycroft   654: int
1.1       cgd       655: ip_dooptions(m)
                    656:        struct mbuf *m;
                    657: {
                    658:        register struct ip *ip = mtod(m, struct ip *);
                    659:        register u_char *cp;
                    660:        register struct ip_timestamp *ipt;
                    661:        register struct in_ifaddr *ia;
                    662:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13      mycroft   663:        struct in_addr *sin, dst;
1.1       cgd       664:        n_time ntime;
                    665:
1.13      mycroft   666:        dst = ip->ip_dst;
1.1       cgd       667:        cp = (u_char *)(ip + 1);
                    668:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    669:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    670:                opt = cp[IPOPT_OPTVAL];
                    671:                if (opt == IPOPT_EOL)
                    672:                        break;
                    673:                if (opt == IPOPT_NOP)
                    674:                        optlen = 1;
                    675:                else {
                    676:                        optlen = cp[IPOPT_OLEN];
                    677:                        if (optlen <= 0 || optlen > cnt) {
                    678:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    679:                                goto bad;
                    680:                        }
                    681:                }
                    682:                switch (opt) {
                    683:
                    684:                default:
                    685:                        break;
                    686:
                    687:                /*
                    688:                 * Source routing with record.
                    689:                 * Find interface with current destination address.
                    690:                 * If none on this machine then drop if strictly routed,
                    691:                 * or do nothing if loosely routed.
                    692:                 * Record interface address and bring up next address
                    693:                 * component.  If strictly routed make sure next
                    694:                 * address is on directly accessible net.
                    695:                 */
                    696:                case IPOPT_LSRR:
                    697:                case IPOPT_SSRR:
                    698:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    699:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    700:                                goto bad;
                    701:                        }
                    702:                        ipaddr.sin_addr = ip->ip_dst;
                    703:                        ia = (struct in_ifaddr *)
                    704:                                ifa_ifwithaddr((struct sockaddr *)&ipaddr);
                    705:                        if (ia == 0) {
                    706:                                if (opt == IPOPT_SSRR) {
                    707:                                        type = ICMP_UNREACH;
                    708:                                        code = ICMP_UNREACH_SRCFAIL;
                    709:                                        goto bad;
                    710:                                }
                    711:                                /*
                    712:                                 * Loose routing, and not at next destination
                    713:                                 * yet; nothing to do except forward.
                    714:                                 */
                    715:                                break;
                    716:                        }
                    717:                        off--;                  /* 0 origin */
                    718:                        if (off > optlen - sizeof(struct in_addr)) {
                    719:                                /*
                    720:                                 * End of source route.  Should be for us.
                    721:                                 */
                    722:                                save_rte(cp, ip->ip_src);
                    723:                                break;
                    724:                        }
                    725:                        /*
                    726:                         * locate outgoing interface
                    727:                         */
                    728:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    729:                            sizeof(ipaddr.sin_addr));
                    730:                        if (opt == IPOPT_SSRR) {
                    731: #define        INA     struct in_ifaddr *
                    732: #define        SA      struct sockaddr *
                    733:                            if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
1.13      mycroft   734:                                ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1.1       cgd       735:                        } else
                    736:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    737:                        if (ia == 0) {
                    738:                                type = ICMP_UNREACH;
                    739:                                code = ICMP_UNREACH_SRCFAIL;
                    740:                                goto bad;
                    741:                        }
                    742:                        ip->ip_dst = ipaddr.sin_addr;
                    743:                        bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
                    744:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    745:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft   746:                        /*
                    747:                         * Let ip_intr's mcast routing check handle mcast pkts
                    748:                         */
                    749:                        forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
1.1       cgd       750:                        break;
                    751:
                    752:                case IPOPT_RR:
                    753:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    754:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    755:                                goto bad;
                    756:                        }
                    757:                        /*
                    758:                         * If no space remains, ignore.
                    759:                         */
                    760:                        off--;                  /* 0 origin */
                    761:                        if (off > optlen - sizeof(struct in_addr))
                    762:                                break;
                    763:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    764:                            sizeof(ipaddr.sin_addr));
                    765:                        /*
                    766:                         * locate outgoing interface; if we're the destination,
                    767:                         * use the incoming interface (should be same).
                    768:                         */
                    769:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    770:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    771:                                type = ICMP_UNREACH;
                    772:                                code = ICMP_UNREACH_HOST;
                    773:                                goto bad;
                    774:                        }
                    775:                        bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
                    776:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    777:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    778:                        break;
                    779:
                    780:                case IPOPT_TS:
                    781:                        code = cp - (u_char *)ip;
                    782:                        ipt = (struct ip_timestamp *)cp;
                    783:                        if (ipt->ipt_len < 5)
                    784:                                goto bad;
1.15      cgd       785:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1       cgd       786:                                if (++ipt->ipt_oflw == 0)
                    787:                                        goto bad;
                    788:                                break;
                    789:                        }
                    790:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    791:                        switch (ipt->ipt_flg) {
                    792:
                    793:                        case IPOPT_TS_TSONLY:
                    794:                                break;
                    795:
                    796:                        case IPOPT_TS_TSANDADDR:
                    797:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    798:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    799:                                        goto bad;
1.13      mycroft   800:                                ipaddr.sin_addr = dst;
                    801:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
                    802:                                                            m->m_pkthdr.rcvif);
                    803:                                if (ia == 0)
                    804:                                        continue;
1.1       cgd       805:                                bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
                    806:                                    (caddr_t)sin, sizeof(struct in_addr));
                    807:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    808:                                break;
                    809:
                    810:                        case IPOPT_TS_PRESPEC:
                    811:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    812:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    813:                                        goto bad;
                    814:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    815:                                    sizeof(struct in_addr));
                    816:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    817:                                        continue;
                    818:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    819:                                break;
                    820:
                    821:                        default:
                    822:                                goto bad;
                    823:                        }
                    824:                        ntime = iptime();
                    825:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    826:                            sizeof(n_time));
                    827:                        ipt->ipt_ptr += sizeof(n_time);
                    828:                }
                    829:        }
                    830:        if (forward) {
                    831:                ip_forward(m, 1);
                    832:                return (1);
1.13      mycroft   833:        }
                    834:        return (0);
1.1       cgd       835: bad:
1.13      mycroft   836:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
                    837:        icmp_error(m, type, code, 0, 0);
                    838:        ipstat.ips_badoptions++;
1.1       cgd       839:        return (1);
                    840: }
                    841:
                    842: /*
                    843:  * Given address of next destination (final or next hop),
                    844:  * return internet address info of interface to be used to get there.
                    845:  */
                    846: struct in_ifaddr *
                    847: ip_rtaddr(dst)
                    848:         struct in_addr dst;
                    849: {
                    850:        register struct sockaddr_in *sin;
                    851:
                    852:        sin = (struct sockaddr_in *) &ipforward_rt.ro_dst;
                    853:
                    854:        if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
                    855:                if (ipforward_rt.ro_rt) {
                    856:                        RTFREE(ipforward_rt.ro_rt);
                    857:                        ipforward_rt.ro_rt = 0;
                    858:                }
                    859:                sin->sin_family = AF_INET;
                    860:                sin->sin_len = sizeof(*sin);
                    861:                sin->sin_addr = dst;
                    862:
                    863:                rtalloc(&ipforward_rt);
                    864:        }
                    865:        if (ipforward_rt.ro_rt == 0)
                    866:                return ((struct in_ifaddr *)0);
                    867:        return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa);
                    868: }
                    869:
                    870: /*
                    871:  * Save incoming source route for use in replies,
                    872:  * to be picked up later by ip_srcroute if the receiver is interested.
                    873:  */
1.13      mycroft   874: void
1.1       cgd       875: save_rte(option, dst)
                    876:        u_char *option;
                    877:        struct in_addr dst;
                    878: {
                    879:        unsigned olen;
                    880:
                    881:        olen = option[IPOPT_OLEN];
                    882: #ifdef DIAGNOSTIC
                    883:        if (ipprintfs)
                    884:                printf("save_rte: olen %d\n", olen);
                    885: #endif
                    886:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    887:                return;
                    888:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    889:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    890:        ip_srcrt.dst = dst;
                    891: }
                    892:
                    893: /*
                    894:  * Retrieve incoming source route for use in replies,
                    895:  * in the same form used by setsockopt.
                    896:  * The first hop is placed before the options, will be removed later.
                    897:  */
                    898: struct mbuf *
                    899: ip_srcroute()
                    900: {
                    901:        register struct in_addr *p, *q;
                    902:        register struct mbuf *m;
                    903:
                    904:        if (ip_nhops == 0)
                    905:                return ((struct mbuf *)0);
                    906:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    907:        if (m == 0)
                    908:                return ((struct mbuf *)0);
                    909:
1.13      mycroft   910: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       911:
                    912:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    913:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    914:            OPTSIZ;
                    915: #ifdef DIAGNOSTIC
                    916:        if (ipprintfs)
                    917:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
                    918: #endif
                    919:
                    920:        /*
                    921:         * First save first hop for return route
                    922:         */
                    923:        p = &ip_srcrt.route[ip_nhops - 1];
                    924:        *(mtod(m, struct in_addr *)) = *p--;
                    925: #ifdef DIAGNOSTIC
                    926:        if (ipprintfs)
                    927:                printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr));
                    928: #endif
                    929:
                    930:        /*
                    931:         * Copy option fields and padding (nop) to mbuf.
                    932:         */
                    933:        ip_srcrt.nop = IPOPT_NOP;
                    934:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    935:        bcopy((caddr_t)&ip_srcrt.nop,
                    936:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    937:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    938:            sizeof(struct in_addr) + OPTSIZ);
                    939: #undef OPTSIZ
                    940:        /*
                    941:         * Record return path as an IP source route,
                    942:         * reversing the path (pointers are now aligned).
                    943:         */
                    944:        while (p >= ip_srcrt.route) {
                    945: #ifdef DIAGNOSTIC
                    946:                if (ipprintfs)
                    947:                        printf(" %lx", ntohl(q->s_addr));
                    948: #endif
                    949:                *q++ = *p--;
                    950:        }
                    951:        /*
                    952:         * Last hop goes to final destination.
                    953:         */
                    954:        *q = ip_srcrt.dst;
                    955: #ifdef DIAGNOSTIC
                    956:        if (ipprintfs)
                    957:                printf(" %lx\n", ntohl(q->s_addr));
                    958: #endif
                    959:        return (m);
                    960: }
                    961:
                    962: /*
                    963:  * Strip out IP options, at higher
                    964:  * level protocol in the kernel.
                    965:  * Second argument is buffer to which options
                    966:  * will be moved, and return value is their length.
                    967:  * XXX should be deleted; last arg currently ignored.
                    968:  */
1.8       mycroft   969: void
1.1       cgd       970: ip_stripoptions(m, mopt)
                    971:        register struct mbuf *m;
                    972:        struct mbuf *mopt;
                    973: {
                    974:        register int i;
                    975:        struct ip *ip = mtod(m, struct ip *);
                    976:        register caddr_t opts;
                    977:        int olen;
                    978:
                    979:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                    980:        opts = (caddr_t)(ip + 1);
                    981:        i = m->m_len - (sizeof (struct ip) + olen);
                    982:        bcopy(opts  + olen, opts, (unsigned)i);
                    983:        m->m_len -= olen;
                    984:        if (m->m_flags & M_PKTHDR)
                    985:                m->m_pkthdr.len -= olen;
                    986:        ip->ip_hl = sizeof(struct ip) >> 2;
                    987: }
                    988:
                    989: u_char inetctlerrmap[PRC_NCMDS] = {
                    990:        0,              0,              0,              0,
                    991:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                    992:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                    993:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                    994:        0,              0,              0,              0,
                    995:        ENOPROTOOPT
                    996: };
                    997:
                    998: /*
                    999:  * Forward a packet.  If some error occurs return the sender
                   1000:  * an icmp packet.  Note we can't always generate a meaningful
                   1001:  * icmp message because icmp doesn't have a large enough repertoire
                   1002:  * of codes and types.
                   1003:  *
                   1004:  * If not forwarding, just drop the packet.  This could be confusing
                   1005:  * if ipforwarding was zero but some routing protocol was advancing
                   1006:  * us as a gateway to somewhere.  However, we must let the routing
                   1007:  * protocol deal with that.
                   1008:  *
                   1009:  * The srcrt parameter indicates whether the packet is being forwarded
                   1010:  * via a source route.
                   1011:  */
1.13      mycroft  1012: void
1.1       cgd      1013: ip_forward(m, srcrt)
                   1014:        struct mbuf *m;
                   1015:        int srcrt;
                   1016: {
                   1017:        register struct ip *ip = mtod(m, struct ip *);
                   1018:        register struct sockaddr_in *sin;
                   1019:        register struct rtentry *rt;
                   1020:        int error, type = 0, code;
                   1021:        struct mbuf *mcopy;
1.13      mycroft  1022:        n_long dest;
                   1023:        struct ifnet *destifp;
1.1       cgd      1024:
1.13      mycroft  1025:        dest = 0;
1.1       cgd      1026: #ifdef DIAGNOSTIC
                   1027:        if (ipprintfs)
                   1028:                printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
                   1029:                        ip->ip_dst, ip->ip_ttl);
                   1030: #endif
                   1031:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1032:                ipstat.ips_cantforward++;
                   1033:                m_freem(m);
                   1034:                return;
                   1035:        }
                   1036:        HTONS(ip->ip_id);
                   1037:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1038:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1039:                return;
                   1040:        }
                   1041:        ip->ip_ttl -= IPTTLDEC;
                   1042:
                   1043:        sin = (struct sockaddr_in *)&ipforward_rt.ro_dst;
                   1044:        if ((rt = ipforward_rt.ro_rt) == 0 ||
                   1045:            ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
                   1046:                if (ipforward_rt.ro_rt) {
                   1047:                        RTFREE(ipforward_rt.ro_rt);
                   1048:                        ipforward_rt.ro_rt = 0;
                   1049:                }
                   1050:                sin->sin_family = AF_INET;
                   1051:                sin->sin_len = sizeof(*sin);
                   1052:                sin->sin_addr = ip->ip_dst;
                   1053:
                   1054:                rtalloc(&ipforward_rt);
                   1055:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1056:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1057:                        return;
                   1058:                }
                   1059:                rt = ipforward_rt.ro_rt;
                   1060:        }
                   1061:
                   1062:        /*
                   1063:         * Save at most 64 bytes of the packet in case
                   1064:         * we need to generate an ICMP message to the src.
                   1065:         */
                   1066:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
                   1067:
                   1068: #ifdef GATEWAY
                   1069:        ip_ifmatrix[rt->rt_ifp->if_index +
                   1070:             if_index * m->m_pkthdr.rcvif->if_index]++;
                   1071: #endif
                   1072:        /*
                   1073:         * If forwarding packet using same interface that it came in on,
                   1074:         * perhaps should send a redirect to sender to shortcut a hop.
                   1075:         * Only send redirect if source is sending directly to us,
                   1076:         * and if packet was not source routed (or has any options).
                   1077:         * Also, don't send redirect if forwarding using a default route
                   1078:         * or a route modified by a redirect.
                   1079:         */
                   1080: #define        satosin(sa)     ((struct sockaddr_in *)(sa))
                   1081:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1082:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
                   1083:            satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
                   1084:            ipsendredirects && !srcrt) {
1.13      mycroft  1085: #define        RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1.15      cgd      1086:                u_int32_t src = ntohl(ip->ip_src.s_addr);
1.1       cgd      1087:
1.13      mycroft  1088:                if (RTA(rt) &&
                   1089:                    (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1.1       cgd      1090:                    if (rt->rt_flags & RTF_GATEWAY)
1.13      mycroft  1091:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1092:                    else
1.13      mycroft  1093:                        dest = ip->ip_dst.s_addr;
                   1094:                    /* Router requirements says to only send host redirects */
1.1       cgd      1095:                    type = ICMP_REDIRECT;
1.13      mycroft  1096:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1097: #ifdef DIAGNOSTIC
                   1098:                    if (ipprintfs)
1.15      cgd      1099:                        printf("redirect (%d) to %lx\n", code, (u_int32_t)dest);
1.1       cgd      1100: #endif
                   1101:                }
                   1102:        }
                   1103:
1.13      mycroft  1104:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt, IP_FORWARDING
1.9       mycroft  1105: #ifdef DIRECTED_BROADCAST
1.13      mycroft  1106:                            | IP_ALLOWBROADCAST
1.9       mycroft  1107: #endif
1.13      mycroft  1108:                                                , 0);
1.1       cgd      1109:        if (error)
                   1110:                ipstat.ips_cantforward++;
                   1111:        else {
                   1112:                ipstat.ips_forward++;
                   1113:                if (type)
                   1114:                        ipstat.ips_redirectsent++;
                   1115:                else {
                   1116:                        if (mcopy)
                   1117:                                m_freem(mcopy);
                   1118:                        return;
                   1119:                }
                   1120:        }
                   1121:        if (mcopy == NULL)
                   1122:                return;
1.13      mycroft  1123:        destifp = NULL;
                   1124:
1.1       cgd      1125:        switch (error) {
                   1126:
                   1127:        case 0:                         /* forwarded, but need redirect */
                   1128:                /* type, code set above */
                   1129:                break;
                   1130:
                   1131:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1132:        case EHOSTUNREACH:
                   1133:        case ENETDOWN:
                   1134:        case EHOSTDOWN:
                   1135:        default:
                   1136:                type = ICMP_UNREACH;
                   1137:                code = ICMP_UNREACH_HOST;
                   1138:                break;
                   1139:
                   1140:        case EMSGSIZE:
                   1141:                type = ICMP_UNREACH;
                   1142:                code = ICMP_UNREACH_NEEDFRAG;
1.13      mycroft  1143:                if (ipforward_rt.ro_rt)
                   1144:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1145:                ipstat.ips_cantfrag++;
                   1146:                break;
                   1147:
                   1148:        case ENOBUFS:
                   1149:                type = ICMP_SOURCEQUENCH;
                   1150:                code = 0;
                   1151:                break;
                   1152:        }
1.13      mycroft  1153:        icmp_error(mcopy, type, code, dest, destifp);
                   1154: }
                   1155:
                   1156: int
                   1157: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1158:        int *name;
                   1159:        u_int namelen;
                   1160:        void *oldp;
                   1161:        size_t *oldlenp;
                   1162:        void *newp;
                   1163:        size_t newlen;
                   1164: {
                   1165:        /* All sysctl names at this level are terminal. */
                   1166:        if (namelen != 1)
                   1167:                return (ENOTDIR);
                   1168:
                   1169:        switch (name[0]) {
                   1170:        case IPCTL_FORWARDING:
                   1171:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
                   1172:        case IPCTL_SENDREDIRECTS:
                   1173:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1174:                        &ipsendredirects));
                   1175:        case IPCTL_DEFTTL:
                   1176:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
                   1177: #ifdef notyet
                   1178:        case IPCTL_DEFMTU:
                   1179:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
                   1180: #endif
                   1181:        default:
                   1182:                return (EOPNOTSUPP);
                   1183:        }
                   1184:        /* NOTREACHED */
1.1       cgd      1185: }

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