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Annotation of src/sys/netinet/ip_input.c, Revision 1.21

1.21    ! mycroft     1: /*     $NetBSD: ip_input.c,v 1.20 1995/06/04 05:58:26 mycroft Exp $    */
1.14      cgd         2:
1.1       cgd         3: /*
1.13      mycroft     4:  * Copyright (c) 1982, 1986, 1988, 1993
                      5:  *     The Regents of the University of California.  All rights reserved.
1.1       cgd         6:  *
                      7:  * Redistribution and use in source and binary forms, with or without
                      8:  * modification, are permitted provided that the following conditions
                      9:  * are met:
                     10:  * 1. Redistributions of source code must retain the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer.
                     12:  * 2. Redistributions in binary form must reproduce the above copyright
                     13:  *    notice, this list of conditions and the following disclaimer in the
                     14:  *    documentation and/or other materials provided with the distribution.
                     15:  * 3. All advertising materials mentioning features or use of this software
                     16:  *    must display the following acknowledgement:
                     17:  *     This product includes software developed by the University of
                     18:  *     California, Berkeley and its contributors.
                     19:  * 4. Neither the name of the University nor the names of its contributors
                     20:  *    may be used to endorse or promote products derived from this software
                     21:  *    without specific prior written permission.
                     22:  *
                     23:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     24:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     25:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     26:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     27:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     28:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     29:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     30:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     31:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     32:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     33:  * SUCH DAMAGE.
                     34:  *
1.14      cgd        35:  *     @(#)ip_input.c  8.2 (Berkeley) 1/4/94
1.1       cgd        36:  */
                     37:
1.5       mycroft    38: #include <sys/param.h>
                     39: #include <sys/systm.h>
                     40: #include <sys/malloc.h>
                     41: #include <sys/mbuf.h>
                     42: #include <sys/domain.h>
                     43: #include <sys/protosw.h>
                     44: #include <sys/socket.h>
                     45: #include <sys/errno.h>
                     46: #include <sys/time.h>
                     47: #include <sys/kernel.h>
1.1       cgd        48:
1.5       mycroft    49: #include <net/if.h>
                     50: #include <net/route.h>
1.1       cgd        51:
1.5       mycroft    52: #include <netinet/in.h>
                     53: #include <netinet/in_systm.h>
                     54: #include <netinet/ip.h>
                     55: #include <netinet/in_pcb.h>
                     56: #include <netinet/in_var.h>
                     57: #include <netinet/ip_var.h>
                     58: #include <netinet/ip_icmp.h>
1.1       cgd        59:
                     60: #ifndef        IPFORWARDING
                     61: #ifdef GATEWAY
                     62: #define        IPFORWARDING    1       /* forward IP packets not for us */
                     63: #else /* GATEWAY */
                     64: #define        IPFORWARDING    0       /* don't forward IP packets not for us */
                     65: #endif /* GATEWAY */
                     66: #endif /* IPFORWARDING */
                     67: #ifndef        IPSENDREDIRECTS
                     68: #define        IPSENDREDIRECTS 1
                     69: #endif
                     70: int    ipforwarding = IPFORWARDING;
                     71: int    ipsendredirects = IPSENDREDIRECTS;
1.13      mycroft    72: int    ip_defttl = IPDEFTTL;
1.1       cgd        73: #ifdef DIAGNOSTIC
                     74: int    ipprintfs = 0;
                     75: #endif
                     76:
                     77: extern struct domain inetdomain;
                     78: extern struct protosw inetsw[];
                     79: u_char ip_protox[IPPROTO_MAX];
                     80: int    ipqmaxlen = IFQ_MAXLEN;
                     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:
1.13      mycroft    99: static void save_rte __P((u_char *, struct in_addr));
1.1       cgd       100: /*
                    101:  * IP initialization: fill in IP protocol switch table.
                    102:  * All protocols not implemented in kernel go to raw IP protocol handler.
                    103:  */
1.8       mycroft   104: void
1.1       cgd       105: ip_init()
                    106: {
                    107:        register struct protosw *pr;
                    108:        register int i;
                    109:
                    110:        pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
                    111:        if (pr == 0)
                    112:                panic("ip_init");
                    113:        for (i = 0; i < IPPROTO_MAX; i++)
                    114:                ip_protox[i] = pr - inetsw;
                    115:        for (pr = inetdomain.dom_protosw;
                    116:            pr < inetdomain.dom_protoswNPROTOSW; pr++)
                    117:                if (pr->pr_domain->dom_family == PF_INET &&
                    118:                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
                    119:                        ip_protox[pr->pr_protocol] = pr - inetsw;
                    120:        ipq.next = ipq.prev = &ipq;
                    121:        ip_id = time.tv_sec & 0xffff;
                    122:        ipintrq.ifq_maxlen = ipqmaxlen;
                    123: }
                    124:
                    125: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    126: struct route ipforward_rt;
                    127:
                    128: /*
                    129:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    130:  * try to reassemble.  Process options.  Pass to next level.
                    131:  */
1.8       mycroft   132: void
1.1       cgd       133: ipintr()
                    134: {
                    135:        register struct ip *ip;
                    136:        register struct mbuf *m;
                    137:        register struct ipq *fp;
                    138:        register struct in_ifaddr *ia;
                    139:        int hlen, s;
                    140:
                    141: next:
                    142:        /*
                    143:         * Get next datagram off input queue and get IP header
                    144:         * in first mbuf.
                    145:         */
                    146:        s = splimp();
                    147:        IF_DEQUEUE(&ipintrq, m);
                    148:        splx(s);
1.13      mycroft   149:        if (m == 0)
1.1       cgd       150:                return;
                    151: #ifdef DIAGNOSTIC
                    152:        if ((m->m_flags & M_PKTHDR) == 0)
                    153:                panic("ipintr no HDR");
                    154: #endif
                    155:        /*
                    156:         * If no IP addresses have been set yet but the interfaces
                    157:         * are receiving, can't do anything with incoming packets yet.
                    158:         */
                    159:        if (in_ifaddr == NULL)
                    160:                goto bad;
                    161:        ipstat.ips_total++;
                    162:        if (m->m_len < sizeof (struct ip) &&
                    163:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    164:                ipstat.ips_toosmall++;
                    165:                goto next;
                    166:        }
                    167:        ip = mtod(m, struct ip *);
1.13      mycroft   168:        if (ip->ip_v != IPVERSION) {
                    169:                ipstat.ips_badvers++;
                    170:                goto bad;
                    171:        }
1.1       cgd       172:        hlen = ip->ip_hl << 2;
                    173:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    174:                ipstat.ips_badhlen++;
                    175:                goto bad;
                    176:        }
                    177:        if (hlen > m->m_len) {
                    178:                if ((m = m_pullup(m, hlen)) == 0) {
                    179:                        ipstat.ips_badhlen++;
                    180:                        goto next;
                    181:                }
                    182:                ip = mtod(m, struct ip *);
                    183:        }
                    184:        if (ip->ip_sum = in_cksum(m, hlen)) {
                    185:                ipstat.ips_badsum++;
                    186:                goto bad;
                    187:        }
                    188:
                    189:        /*
                    190:         * Convert fields to host representation.
                    191:         */
                    192:        NTOHS(ip->ip_len);
                    193:        if (ip->ip_len < hlen) {
                    194:                ipstat.ips_badlen++;
                    195:                goto bad;
                    196:        }
                    197:        NTOHS(ip->ip_id);
                    198:        NTOHS(ip->ip_off);
                    199:
                    200:        /*
                    201:         * Check that the amount of data in the buffers
                    202:         * is as at least much as the IP header would have us expect.
                    203:         * Trim mbufs if longer than we expect.
                    204:         * Drop packet if shorter than we expect.
                    205:         */
                    206:        if (m->m_pkthdr.len < ip->ip_len) {
                    207:                ipstat.ips_tooshort++;
                    208:                goto bad;
                    209:        }
                    210:        if (m->m_pkthdr.len > ip->ip_len) {
                    211:                if (m->m_len == m->m_pkthdr.len) {
                    212:                        m->m_len = ip->ip_len;
                    213:                        m->m_pkthdr.len = ip->ip_len;
                    214:                } else
                    215:                        m_adj(m, ip->ip_len - m->m_pkthdr.len);
                    216:        }
                    217:
                    218:        /*
                    219:         * Process options and, if not destined for us,
                    220:         * ship it on.  ip_dooptions returns 1 when an
                    221:         * error was detected (causing an icmp message
                    222:         * to be sent and the original packet to be freed).
                    223:         */
                    224:        ip_nhops = 0;           /* for source routed packets */
                    225:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    226:                goto next;
                    227:
                    228:        /*
                    229:         * Check our list of addresses, to see if the packet is for us.
                    230:         */
                    231:        for (ia = in_ifaddr; ia; ia = ia->ia_next) {
1.20      mycroft   232:                if (ip->ip_dst.s_addr == ia->ia_addr.sin_addr.s_addr)
1.1       cgd       233:                        goto ours;
                    234:                if (
                    235: #ifdef DIRECTED_BROADCAST
                    236:                    ia->ia_ifp == m->m_pkthdr.rcvif &&
                    237: #endif
                    238:                    (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.20      mycroft   239:                        if (ip->ip_dst.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
                    240:                            ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr ||
                    241:                            /*
                    242:                             * Look for all-0's host part (old broadcast addr),
                    243:                             * either for subnet or net.
                    244:                             */
                    245:                            ip->ip_dst.s_addr == ia->ia_subnet ||
1.18      mycroft   246:                            ip->ip_dst.s_addr == ia->ia_net)
1.1       cgd       247:                                goto ours;
                    248:                }
                    249:        }
1.18      mycroft   250:        if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4       hpeyerl   251:                struct in_multi *inm;
                    252: #ifdef MROUTING
                    253:                extern struct socket *ip_mrouter;
1.10      brezak    254:
                    255:                if (m->m_flags & M_EXT) {
                    256:                        if ((m = m_pullup(m, hlen)) == 0) {
                    257:                                ipstat.ips_toosmall++;
                    258:                                goto next;
                    259:                        }
                    260:                        ip = mtod(m, struct ip *);
                    261:                }
1.4       hpeyerl   262:
                    263:                if (ip_mrouter) {
                    264:                        /*
                    265:                         * If we are acting as a multicast router, all
                    266:                         * incoming multicast packets are passed to the
                    267:                         * kernel-level multicast forwarding function.
                    268:                         * The packet is returned (relatively) intact; if
                    269:                         * ip_mforward() returns a non-zero value, the packet
                    270:                         * must be discarded, else it may be accepted below.
                    271:                         *
                    272:                         * (The IP ident field is put in the same byte order
                    273:                         * as expected when ip_mforward() is called from
                    274:                         * ip_output().)
                    275:                         */
                    276:                        ip->ip_id = htons(ip->ip_id);
1.13      mycroft   277:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    278:                                ipstat.ips_cantforward++;
1.4       hpeyerl   279:                                m_freem(m);
                    280:                                goto next;
                    281:                        }
                    282:                        ip->ip_id = ntohs(ip->ip_id);
                    283:
                    284:                        /*
                    285:                         * The process-level routing demon needs to receive
                    286:                         * all multicast IGMP packets, whether or not this
                    287:                         * host belongs to their destination groups.
                    288:                         */
                    289:                        if (ip->ip_p == IPPROTO_IGMP)
                    290:                                goto ours;
1.13      mycroft   291:                        ipstat.ips_forward++;
1.4       hpeyerl   292:                }
                    293: #endif
                    294:                /*
                    295:                 * See if we belong to the destination multicast group on the
                    296:                 * arrival interface.
                    297:                 */
                    298:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    299:                if (inm == NULL) {
1.13      mycroft   300:                        ipstat.ips_cantforward++;
1.4       hpeyerl   301:                        m_freem(m);
                    302:                        goto next;
                    303:                }
                    304:                goto ours;
                    305:        }
1.19      mycroft   306:        if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
                    307:            ip->ip_dst.s_addr == INADDR_ANY)
1.1       cgd       308:                goto ours;
                    309:
                    310:        /*
                    311:         * Not for us; forward if possible and desirable.
                    312:         */
                    313:        if (ipforwarding == 0) {
                    314:                ipstat.ips_cantforward++;
                    315:                m_freem(m);
                    316:        } else
                    317:                ip_forward(m, 0);
                    318:        goto next;
                    319:
                    320: ours:
                    321:        /*
                    322:         * If offset or IP_MF are set, must reassemble.
                    323:         * Otherwise, nothing need be done.
                    324:         * (We could look in the reassembly queue to see
                    325:         * if the packet was previously fragmented,
                    326:         * but it's not worth the time; just let them time out.)
                    327:         */
                    328:        if (ip->ip_off &~ IP_DF) {
                    329:                if (m->m_flags & M_EXT) {               /* XXX */
                    330:                        if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
                    331:                                ipstat.ips_toosmall++;
                    332:                                goto next;
                    333:                        }
                    334:                        ip = mtod(m, struct ip *);
                    335:                }
                    336:                /*
                    337:                 * Look for queue of fragments
                    338:                 * of this datagram.
                    339:                 */
                    340:                for (fp = ipq.next; fp != &ipq; fp = fp->next)
                    341:                        if (ip->ip_id == fp->ipq_id &&
                    342:                            ip->ip_src.s_addr == fp->ipq_src.s_addr &&
                    343:                            ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
                    344:                            ip->ip_p == fp->ipq_p)
                    345:                                goto found;
                    346:                fp = 0;
                    347: found:
                    348:
                    349:                /*
                    350:                 * Adjust ip_len to not reflect header,
                    351:                 * set ip_mff if more fragments are expected,
                    352:                 * convert offset of this to bytes.
                    353:                 */
                    354:                ip->ip_len -= hlen;
1.13      mycroft   355:                ((struct ipasfrag *)ip)->ipf_mff &= ~1;
1.16      cgd       356:                if (ip->ip_off & IP_MF) {
                    357:                        /*
                    358:                         * Make sure that fragments have a data length
                    359:                         * that's a non-zero multiple of 8 bytes.
                    360:                         */
1.17      cgd       361:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16      cgd       362:                                ipstat.ips_badfrags++;
                    363:                                goto bad;
                    364:                        }
1.13      mycroft   365:                        ((struct ipasfrag *)ip)->ipf_mff |= 1;
1.16      cgd       366:                }
1.1       cgd       367:                ip->ip_off <<= 3;
                    368:
                    369:                /*
                    370:                 * If datagram marked as having more fragments
                    371:                 * or if this is not the first fragment,
                    372:                 * attempt reassembly; if it succeeds, proceed.
                    373:                 */
1.13      mycroft   374:                if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) {
1.1       cgd       375:                        ipstat.ips_fragments++;
                    376:                        ip = ip_reass((struct ipasfrag *)ip, fp);
                    377:                        if (ip == 0)
                    378:                                goto next;
1.13      mycroft   379:                        ipstat.ips_reassembled++;
1.1       cgd       380:                        m = dtom(ip);
                    381:                } else
                    382:                        if (fp)
                    383:                                ip_freef(fp);
                    384:        } else
                    385:                ip->ip_len -= hlen;
                    386:
                    387:        /*
                    388:         * Switch out to protocol's input routine.
                    389:         */
                    390:        ipstat.ips_delivered++;
                    391:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    392:        goto next;
                    393: bad:
                    394:        m_freem(m);
                    395:        goto next;
                    396: }
                    397:
                    398: /*
                    399:  * Take incoming datagram fragment and try to
                    400:  * reassemble it into whole datagram.  If a chain for
                    401:  * reassembly of this datagram already exists, then it
                    402:  * is given as fp; otherwise have to make a chain.
                    403:  */
                    404: struct ip *
                    405: ip_reass(ip, fp)
                    406:        register struct ipasfrag *ip;
                    407:        register struct ipq *fp;
                    408: {
                    409:        register struct mbuf *m = dtom(ip);
                    410:        register struct ipasfrag *q;
                    411:        struct mbuf *t;
                    412:        int hlen = ip->ip_hl << 2;
                    413:        int i, next;
                    414:
                    415:        /*
                    416:         * Presence of header sizes in mbufs
                    417:         * would confuse code below.
                    418:         */
                    419:        m->m_data += hlen;
                    420:        m->m_len -= hlen;
                    421:
                    422:        /*
                    423:         * If first fragment to arrive, create a reassembly queue.
                    424:         */
                    425:        if (fp == 0) {
                    426:                if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
                    427:                        goto dropfrag;
                    428:                fp = mtod(t, struct ipq *);
                    429:                insque(fp, &ipq);
                    430:                fp->ipq_ttl = IPFRAGTTL;
                    431:                fp->ipq_p = ip->ip_p;
                    432:                fp->ipq_id = ip->ip_id;
                    433:                fp->ipq_next = fp->ipq_prev = (struct ipasfrag *)fp;
                    434:                fp->ipq_src = ((struct ip *)ip)->ip_src;
                    435:                fp->ipq_dst = ((struct ip *)ip)->ip_dst;
                    436:                q = (struct ipasfrag *)fp;
                    437:                goto insert;
                    438:        }
                    439:
                    440:        /*
                    441:         * Find a segment which begins after this one does.
                    442:         */
                    443:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next)
                    444:                if (q->ip_off > ip->ip_off)
                    445:                        break;
                    446:
                    447:        /*
                    448:         * If there is a preceding segment, it may provide some of
                    449:         * our data already.  If so, drop the data from the incoming
                    450:         * segment.  If it provides all of our data, drop us.
                    451:         */
                    452:        if (q->ipf_prev != (struct ipasfrag *)fp) {
                    453:                i = q->ipf_prev->ip_off + q->ipf_prev->ip_len - ip->ip_off;
                    454:                if (i > 0) {
                    455:                        if (i >= ip->ip_len)
                    456:                                goto dropfrag;
                    457:                        m_adj(dtom(ip), i);
                    458:                        ip->ip_off += i;
                    459:                        ip->ip_len -= i;
                    460:                }
                    461:        }
                    462:
                    463:        /*
                    464:         * While we overlap succeeding segments trim them or,
                    465:         * if they are completely covered, dequeue them.
                    466:         */
                    467:        while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) {
                    468:                i = (ip->ip_off + ip->ip_len) - q->ip_off;
                    469:                if (i < q->ip_len) {
                    470:                        q->ip_len -= i;
                    471:                        q->ip_off += i;
                    472:                        m_adj(dtom(q), i);
                    473:                        break;
                    474:                }
                    475:                q = q->ipf_next;
                    476:                m_freem(dtom(q->ipf_prev));
                    477:                ip_deq(q->ipf_prev);
                    478:        }
                    479:
                    480: insert:
                    481:        /*
                    482:         * Stick new segment in its place;
                    483:         * check for complete reassembly.
                    484:         */
                    485:        ip_enq(ip, q->ipf_prev);
                    486:        next = 0;
                    487:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) {
                    488:                if (q->ip_off != next)
                    489:                        return (0);
                    490:                next += q->ip_len;
                    491:        }
1.13      mycroft   492:        if (q->ipf_prev->ipf_mff & 1)
1.1       cgd       493:                return (0);
                    494:
                    495:        /*
                    496:         * Reassembly is complete; concatenate fragments.
                    497:         */
                    498:        q = fp->ipq_next;
                    499:        m = dtom(q);
                    500:        t = m->m_next;
                    501:        m->m_next = 0;
                    502:        m_cat(m, t);
                    503:        q = q->ipf_next;
                    504:        while (q != (struct ipasfrag *)fp) {
                    505:                t = dtom(q);
                    506:                q = q->ipf_next;
                    507:                m_cat(m, t);
                    508:        }
                    509:
                    510:        /*
                    511:         * Create header for new ip packet by
                    512:         * modifying header of first packet;
                    513:         * dequeue and discard fragment reassembly header.
                    514:         * Make header visible.
                    515:         */
                    516:        ip = fp->ipq_next;
                    517:        ip->ip_len = next;
1.13      mycroft   518:        ip->ipf_mff &= ~1;
1.1       cgd       519:        ((struct ip *)ip)->ip_src = fp->ipq_src;
                    520:        ((struct ip *)ip)->ip_dst = fp->ipq_dst;
                    521:        remque(fp);
                    522:        (void) m_free(dtom(fp));
                    523:        m = dtom(ip);
                    524:        m->m_len += (ip->ip_hl << 2);
                    525:        m->m_data -= (ip->ip_hl << 2);
                    526:        /* some debugging cruft by sklower, below, will go away soon */
                    527:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
                    528:                register int plen = 0;
                    529:                for (t = m; m; m = m->m_next)
                    530:                        plen += m->m_len;
                    531:                t->m_pkthdr.len = plen;
                    532:        }
                    533:        return ((struct ip *)ip);
                    534:
                    535: dropfrag:
                    536:        ipstat.ips_fragdropped++;
                    537:        m_freem(m);
                    538:        return (0);
                    539: }
                    540:
                    541: /*
                    542:  * Free a fragment reassembly header and all
                    543:  * associated datagrams.
                    544:  */
1.8       mycroft   545: void
1.1       cgd       546: ip_freef(fp)
                    547:        struct ipq *fp;
                    548: {
                    549:        register struct ipasfrag *q, *p;
                    550:
                    551:        for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = p) {
                    552:                p = q->ipf_next;
                    553:                ip_deq(q);
                    554:                m_freem(dtom(q));
                    555:        }
                    556:        remque(fp);
                    557:        (void) m_free(dtom(fp));
                    558: }
                    559:
                    560: /*
                    561:  * Put an ip fragment on a reassembly chain.
                    562:  * Like insque, but pointers in middle of structure.
                    563:  */
1.8       mycroft   564: void
1.1       cgd       565: ip_enq(p, prev)
                    566:        register struct ipasfrag *p, *prev;
                    567: {
                    568:
                    569:        p->ipf_prev = prev;
                    570:        p->ipf_next = prev->ipf_next;
                    571:        prev->ipf_next->ipf_prev = p;
                    572:        prev->ipf_next = p;
                    573: }
                    574:
                    575: /*
                    576:  * To ip_enq as remque is to insque.
                    577:  */
1.8       mycroft   578: void
1.1       cgd       579: ip_deq(p)
                    580:        register struct ipasfrag *p;
                    581: {
                    582:
                    583:        p->ipf_prev->ipf_next = p->ipf_next;
                    584:        p->ipf_next->ipf_prev = p->ipf_prev;
                    585: }
                    586:
                    587: /*
                    588:  * IP timer processing;
                    589:  * if a timer expires on a reassembly
                    590:  * queue, discard it.
                    591:  */
1.8       mycroft   592: void
1.1       cgd       593: ip_slowtimo()
                    594: {
                    595:        register struct ipq *fp;
                    596:        int s = splnet();
                    597:
                    598:        fp = ipq.next;
                    599:        if (fp == 0) {
                    600:                splx(s);
                    601:                return;
                    602:        }
                    603:        while (fp != &ipq) {
                    604:                --fp->ipq_ttl;
                    605:                fp = fp->next;
                    606:                if (fp->prev->ipq_ttl == 0) {
                    607:                        ipstat.ips_fragtimeout++;
                    608:                        ip_freef(fp->prev);
                    609:                }
                    610:        }
                    611:        splx(s);
                    612: }
                    613:
                    614: /*
                    615:  * Drain off all datagram fragments.
                    616:  */
1.8       mycroft   617: void
1.1       cgd       618: ip_drain()
                    619: {
                    620:
                    621:        while (ipq.next != &ipq) {
                    622:                ipstat.ips_fragdropped++;
                    623:                ip_freef(ipq.next);
                    624:        }
                    625: }
                    626:
                    627: /*
                    628:  * Do option processing on a datagram,
                    629:  * possibly discarding it if bad options are encountered,
                    630:  * or forwarding it if source-routed.
                    631:  * Returns 1 if packet has been forwarded/freed,
                    632:  * 0 if the packet should be processed further.
                    633:  */
1.8       mycroft   634: int
1.1       cgd       635: ip_dooptions(m)
                    636:        struct mbuf *m;
                    637: {
                    638:        register struct ip *ip = mtod(m, struct ip *);
                    639:        register u_char *cp;
                    640:        register struct ip_timestamp *ipt;
                    641:        register struct in_ifaddr *ia;
                    642:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13      mycroft   643:        struct in_addr *sin, dst;
1.1       cgd       644:        n_time ntime;
                    645:
1.13      mycroft   646:        dst = ip->ip_dst;
1.1       cgd       647:        cp = (u_char *)(ip + 1);
                    648:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    649:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    650:                opt = cp[IPOPT_OPTVAL];
                    651:                if (opt == IPOPT_EOL)
                    652:                        break;
                    653:                if (opt == IPOPT_NOP)
                    654:                        optlen = 1;
                    655:                else {
                    656:                        optlen = cp[IPOPT_OLEN];
                    657:                        if (optlen <= 0 || optlen > cnt) {
                    658:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    659:                                goto bad;
                    660:                        }
                    661:                }
                    662:                switch (opt) {
                    663:
                    664:                default:
                    665:                        break;
                    666:
                    667:                /*
                    668:                 * Source routing with record.
                    669:                 * Find interface with current destination address.
                    670:                 * If none on this machine then drop if strictly routed,
                    671:                 * or do nothing if loosely routed.
                    672:                 * Record interface address and bring up next address
                    673:                 * component.  If strictly routed make sure next
                    674:                 * address is on directly accessible net.
                    675:                 */
                    676:                case IPOPT_LSRR:
                    677:                case IPOPT_SSRR:
                    678:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    679:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    680:                                goto bad;
                    681:                        }
                    682:                        ipaddr.sin_addr = ip->ip_dst;
1.19      mycroft   683:                        ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1       cgd       684:                        if (ia == 0) {
                    685:                                if (opt == IPOPT_SSRR) {
                    686:                                        type = ICMP_UNREACH;
                    687:                                        code = ICMP_UNREACH_SRCFAIL;
                    688:                                        goto bad;
                    689:                                }
                    690:                                /*
                    691:                                 * Loose routing, and not at next destination
                    692:                                 * yet; nothing to do except forward.
                    693:                                 */
                    694:                                break;
                    695:                        }
                    696:                        off--;                  /* 0 origin */
                    697:                        if (off > optlen - sizeof(struct in_addr)) {
                    698:                                /*
                    699:                                 * End of source route.  Should be for us.
                    700:                                 */
                    701:                                save_rte(cp, ip->ip_src);
                    702:                                break;
                    703:                        }
                    704:                        /*
                    705:                         * locate outgoing interface
                    706:                         */
                    707:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    708:                            sizeof(ipaddr.sin_addr));
                    709:                        if (opt == IPOPT_SSRR) {
                    710: #define        INA     struct in_ifaddr *
                    711: #define        SA      struct sockaddr *
                    712:                            if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
1.13      mycroft   713:                                ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1.1       cgd       714:                        } else
                    715:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    716:                        if (ia == 0) {
                    717:                                type = ICMP_UNREACH;
                    718:                                code = ICMP_UNREACH_SRCFAIL;
                    719:                                goto bad;
                    720:                        }
                    721:                        ip->ip_dst = ipaddr.sin_addr;
1.20      mycroft   722:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       723:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    724:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft   725:                        /*
                    726:                         * Let ip_intr's mcast routing check handle mcast pkts
                    727:                         */
1.18      mycroft   728:                        forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1       cgd       729:                        break;
                    730:
                    731:                case IPOPT_RR:
                    732:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    733:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    734:                                goto bad;
                    735:                        }
                    736:                        /*
                    737:                         * If no space remains, ignore.
                    738:                         */
                    739:                        off--;                  /* 0 origin */
                    740:                        if (off > optlen - sizeof(struct in_addr))
                    741:                                break;
                    742:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    743:                            sizeof(ipaddr.sin_addr));
                    744:                        /*
                    745:                         * locate outgoing interface; if we're the destination,
                    746:                         * use the incoming interface (should be same).
                    747:                         */
                    748:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    749:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    750:                                type = ICMP_UNREACH;
                    751:                                code = ICMP_UNREACH_HOST;
                    752:                                goto bad;
                    753:                        }
1.20      mycroft   754:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       755:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    756:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    757:                        break;
                    758:
                    759:                case IPOPT_TS:
                    760:                        code = cp - (u_char *)ip;
                    761:                        ipt = (struct ip_timestamp *)cp;
                    762:                        if (ipt->ipt_len < 5)
                    763:                                goto bad;
1.15      cgd       764:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1       cgd       765:                                if (++ipt->ipt_oflw == 0)
                    766:                                        goto bad;
                    767:                                break;
                    768:                        }
                    769:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    770:                        switch (ipt->ipt_flg) {
                    771:
                    772:                        case IPOPT_TS_TSONLY:
                    773:                                break;
                    774:
                    775:                        case IPOPT_TS_TSANDADDR:
                    776:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    777:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    778:                                        goto bad;
1.13      mycroft   779:                                ipaddr.sin_addr = dst;
                    780:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
                    781:                                                            m->m_pkthdr.rcvif);
                    782:                                if (ia == 0)
                    783:                                        continue;
1.20      mycroft   784:                                bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       785:                                    (caddr_t)sin, sizeof(struct in_addr));
                    786:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    787:                                break;
                    788:
                    789:                        case IPOPT_TS_PRESPEC:
                    790:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    791:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    792:                                        goto bad;
                    793:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    794:                                    sizeof(struct in_addr));
                    795:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    796:                                        continue;
                    797:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    798:                                break;
                    799:
                    800:                        default:
                    801:                                goto bad;
                    802:                        }
                    803:                        ntime = iptime();
                    804:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    805:                            sizeof(n_time));
                    806:                        ipt->ipt_ptr += sizeof(n_time);
                    807:                }
                    808:        }
                    809:        if (forward) {
                    810:                ip_forward(m, 1);
                    811:                return (1);
1.13      mycroft   812:        }
                    813:        return (0);
1.1       cgd       814: bad:
1.13      mycroft   815:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
                    816:        icmp_error(m, type, code, 0, 0);
                    817:        ipstat.ips_badoptions++;
1.1       cgd       818:        return (1);
                    819: }
                    820:
                    821: /*
                    822:  * Given address of next destination (final or next hop),
                    823:  * return internet address info of interface to be used to get there.
                    824:  */
                    825: struct in_ifaddr *
                    826: ip_rtaddr(dst)
                    827:         struct in_addr dst;
                    828: {
                    829:        register struct sockaddr_in *sin;
                    830:
1.19      mycroft   831:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd       832:
                    833:        if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
                    834:                if (ipforward_rt.ro_rt) {
                    835:                        RTFREE(ipforward_rt.ro_rt);
                    836:                        ipforward_rt.ro_rt = 0;
                    837:                }
                    838:                sin->sin_family = AF_INET;
                    839:                sin->sin_len = sizeof(*sin);
                    840:                sin->sin_addr = dst;
                    841:
                    842:                rtalloc(&ipforward_rt);
                    843:        }
                    844:        if (ipforward_rt.ro_rt == 0)
                    845:                return ((struct in_ifaddr *)0);
1.19      mycroft   846:        return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1       cgd       847: }
                    848:
                    849: /*
                    850:  * Save incoming source route for use in replies,
                    851:  * to be picked up later by ip_srcroute if the receiver is interested.
                    852:  */
1.13      mycroft   853: void
1.1       cgd       854: save_rte(option, dst)
                    855:        u_char *option;
                    856:        struct in_addr dst;
                    857: {
                    858:        unsigned olen;
                    859:
                    860:        olen = option[IPOPT_OLEN];
                    861: #ifdef DIAGNOSTIC
                    862:        if (ipprintfs)
                    863:                printf("save_rte: olen %d\n", olen);
                    864: #endif
                    865:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    866:                return;
                    867:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    868:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    869:        ip_srcrt.dst = dst;
                    870: }
                    871:
                    872: /*
                    873:  * Retrieve incoming source route for use in replies,
                    874:  * in the same form used by setsockopt.
                    875:  * The first hop is placed before the options, will be removed later.
                    876:  */
                    877: struct mbuf *
                    878: ip_srcroute()
                    879: {
                    880:        register struct in_addr *p, *q;
                    881:        register struct mbuf *m;
                    882:
                    883:        if (ip_nhops == 0)
                    884:                return ((struct mbuf *)0);
                    885:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    886:        if (m == 0)
                    887:                return ((struct mbuf *)0);
                    888:
1.13      mycroft   889: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       890:
                    891:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    892:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    893:            OPTSIZ;
                    894: #ifdef DIAGNOSTIC
                    895:        if (ipprintfs)
                    896:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
                    897: #endif
                    898:
                    899:        /*
                    900:         * First save first hop for return route
                    901:         */
                    902:        p = &ip_srcrt.route[ip_nhops - 1];
                    903:        *(mtod(m, struct in_addr *)) = *p--;
                    904: #ifdef DIAGNOSTIC
                    905:        if (ipprintfs)
                    906:                printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr));
                    907: #endif
                    908:
                    909:        /*
                    910:         * Copy option fields and padding (nop) to mbuf.
                    911:         */
                    912:        ip_srcrt.nop = IPOPT_NOP;
                    913:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    914:        bcopy((caddr_t)&ip_srcrt.nop,
                    915:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    916:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    917:            sizeof(struct in_addr) + OPTSIZ);
                    918: #undef OPTSIZ
                    919:        /*
                    920:         * Record return path as an IP source route,
                    921:         * reversing the path (pointers are now aligned).
                    922:         */
                    923:        while (p >= ip_srcrt.route) {
                    924: #ifdef DIAGNOSTIC
                    925:                if (ipprintfs)
                    926:                        printf(" %lx", ntohl(q->s_addr));
                    927: #endif
                    928:                *q++ = *p--;
                    929:        }
                    930:        /*
                    931:         * Last hop goes to final destination.
                    932:         */
                    933:        *q = ip_srcrt.dst;
                    934: #ifdef DIAGNOSTIC
                    935:        if (ipprintfs)
                    936:                printf(" %lx\n", ntohl(q->s_addr));
                    937: #endif
                    938:        return (m);
                    939: }
                    940:
                    941: /*
                    942:  * Strip out IP options, at higher
                    943:  * level protocol in the kernel.
                    944:  * Second argument is buffer to which options
                    945:  * will be moved, and return value is their length.
                    946:  * XXX should be deleted; last arg currently ignored.
                    947:  */
1.8       mycroft   948: void
1.1       cgd       949: ip_stripoptions(m, mopt)
                    950:        register struct mbuf *m;
                    951:        struct mbuf *mopt;
                    952: {
                    953:        register int i;
                    954:        struct ip *ip = mtod(m, struct ip *);
                    955:        register caddr_t opts;
                    956:        int olen;
                    957:
                    958:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                    959:        opts = (caddr_t)(ip + 1);
                    960:        i = m->m_len - (sizeof (struct ip) + olen);
                    961:        bcopy(opts  + olen, opts, (unsigned)i);
                    962:        m->m_len -= olen;
                    963:        if (m->m_flags & M_PKTHDR)
                    964:                m->m_pkthdr.len -= olen;
                    965:        ip->ip_hl = sizeof(struct ip) >> 2;
                    966: }
                    967:
                    968: u_char inetctlerrmap[PRC_NCMDS] = {
                    969:        0,              0,              0,              0,
                    970:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                    971:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                    972:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                    973:        0,              0,              0,              0,
                    974:        ENOPROTOOPT
                    975: };
                    976:
                    977: /*
                    978:  * Forward a packet.  If some error occurs return the sender
                    979:  * an icmp packet.  Note we can't always generate a meaningful
                    980:  * icmp message because icmp doesn't have a large enough repertoire
                    981:  * of codes and types.
                    982:  *
                    983:  * If not forwarding, just drop the packet.  This could be confusing
                    984:  * if ipforwarding was zero but some routing protocol was advancing
                    985:  * us as a gateway to somewhere.  However, we must let the routing
                    986:  * protocol deal with that.
                    987:  *
                    988:  * The srcrt parameter indicates whether the packet is being forwarded
                    989:  * via a source route.
                    990:  */
1.13      mycroft   991: void
1.1       cgd       992: ip_forward(m, srcrt)
                    993:        struct mbuf *m;
                    994:        int srcrt;
                    995: {
                    996:        register struct ip *ip = mtod(m, struct ip *);
                    997:        register struct sockaddr_in *sin;
                    998:        register struct rtentry *rt;
                    999:        int error, type = 0, code;
                   1000:        struct mbuf *mcopy;
1.13      mycroft  1001:        n_long dest;
                   1002:        struct ifnet *destifp;
1.1       cgd      1003:
1.13      mycroft  1004:        dest = 0;
1.1       cgd      1005: #ifdef DIAGNOSTIC
                   1006:        if (ipprintfs)
                   1007:                printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
                   1008:                        ip->ip_dst, ip->ip_ttl);
                   1009: #endif
                   1010:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1011:                ipstat.ips_cantforward++;
                   1012:                m_freem(m);
                   1013:                return;
                   1014:        }
                   1015:        HTONS(ip->ip_id);
                   1016:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1017:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1018:                return;
                   1019:        }
                   1020:        ip->ip_ttl -= IPTTLDEC;
                   1021:
1.19      mycroft  1022:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1023:        if ((rt = ipforward_rt.ro_rt) == 0 ||
                   1024:            ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
                   1025:                if (ipforward_rt.ro_rt) {
                   1026:                        RTFREE(ipforward_rt.ro_rt);
                   1027:                        ipforward_rt.ro_rt = 0;
                   1028:                }
                   1029:                sin->sin_family = AF_INET;
                   1030:                sin->sin_len = sizeof(*sin);
                   1031:                sin->sin_addr = ip->ip_dst;
                   1032:
                   1033:                rtalloc(&ipforward_rt);
                   1034:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1035:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1036:                        return;
                   1037:                }
                   1038:                rt = ipforward_rt.ro_rt;
                   1039:        }
                   1040:
                   1041:        /*
                   1042:         * Save at most 64 bytes of the packet in case
                   1043:         * we need to generate an ICMP message to the src.
                   1044:         */
                   1045:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
                   1046:
                   1047:        /*
                   1048:         * If forwarding packet using same interface that it came in on,
                   1049:         * perhaps should send a redirect to sender to shortcut a hop.
                   1050:         * Only send redirect if source is sending directly to us,
                   1051:         * and if packet was not source routed (or has any options).
                   1052:         * Also, don't send redirect if forwarding using a default route
                   1053:         * or a route modified by a redirect.
                   1054:         */
                   1055:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1056:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
                   1057:            satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
                   1058:            ipsendredirects && !srcrt) {
1.19      mycroft  1059:                if (rt->rt_ifa &&
                   1060:                    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
                   1061:                    ifatoia(rt->rt_ifa)->ia_subnet) {
1.1       cgd      1062:                    if (rt->rt_flags & RTF_GATEWAY)
1.13      mycroft  1063:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1064:                    else
1.13      mycroft  1065:                        dest = ip->ip_dst.s_addr;
                   1066:                    /* Router requirements says to only send host redirects */
1.1       cgd      1067:                    type = ICMP_REDIRECT;
1.13      mycroft  1068:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1069: #ifdef DIAGNOSTIC
                   1070:                    if (ipprintfs)
1.15      cgd      1071:                        printf("redirect (%d) to %lx\n", code, (u_int32_t)dest);
1.1       cgd      1072: #endif
                   1073:                }
                   1074:        }
                   1075:
1.13      mycroft  1076:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt, IP_FORWARDING
1.9       mycroft  1077: #ifdef DIRECTED_BROADCAST
1.13      mycroft  1078:                            | IP_ALLOWBROADCAST
1.9       mycroft  1079: #endif
1.13      mycroft  1080:                                                , 0);
1.1       cgd      1081:        if (error)
                   1082:                ipstat.ips_cantforward++;
                   1083:        else {
                   1084:                ipstat.ips_forward++;
                   1085:                if (type)
                   1086:                        ipstat.ips_redirectsent++;
                   1087:                else {
                   1088:                        if (mcopy)
                   1089:                                m_freem(mcopy);
                   1090:                        return;
                   1091:                }
                   1092:        }
                   1093:        if (mcopy == NULL)
                   1094:                return;
1.13      mycroft  1095:        destifp = NULL;
                   1096:
1.1       cgd      1097:        switch (error) {
                   1098:
                   1099:        case 0:                         /* forwarded, but need redirect */
                   1100:                /* type, code set above */
                   1101:                break;
                   1102:
                   1103:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1104:        case EHOSTUNREACH:
                   1105:        case ENETDOWN:
                   1106:        case EHOSTDOWN:
                   1107:        default:
                   1108:                type = ICMP_UNREACH;
                   1109:                code = ICMP_UNREACH_HOST;
                   1110:                break;
                   1111:
                   1112:        case EMSGSIZE:
                   1113:                type = ICMP_UNREACH;
                   1114:                code = ICMP_UNREACH_NEEDFRAG;
1.13      mycroft  1115:                if (ipforward_rt.ro_rt)
                   1116:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1117:                ipstat.ips_cantfrag++;
                   1118:                break;
                   1119:
                   1120:        case ENOBUFS:
                   1121:                type = ICMP_SOURCEQUENCH;
                   1122:                code = 0;
                   1123:                break;
                   1124:        }
1.13      mycroft  1125:        icmp_error(mcopy, type, code, dest, destifp);
                   1126: }
                   1127:
                   1128: int
                   1129: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1130:        int *name;
                   1131:        u_int namelen;
                   1132:        void *oldp;
                   1133:        size_t *oldlenp;
                   1134:        void *newp;
                   1135:        size_t newlen;
                   1136: {
                   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
                   1153:        default:
                   1154:                return (EOPNOTSUPP);
                   1155:        }
                   1156:        /* NOTREACHED */
1.1       cgd      1157: }

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