[BACK]Return to ip_input.c CVS log [TXT][DIR] Up to [cvs.NetBSD.org] / src / sys / netinet

Annotation of src/sys/netinet/ip_input.c, Revision 1.27

1.27    ! thorpej     1: /*     $NetBSD: ip_input.c,v 1.26 1996/01/15 21:11:55 thorpej Exp $    */
1.14      cgd         2:
1.1       cgd         3: /*
1.13      mycroft     4:  * Copyright (c) 1982, 1986, 1988, 1993
                      5:  *     The Regents of the University of California.  All rights reserved.
1.1       cgd         6:  *
                      7:  * Redistribution and use in source and binary forms, with or without
                      8:  * modification, are permitted provided that the following conditions
                      9:  * are met:
                     10:  * 1. Redistributions of source code must retain the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer.
                     12:  * 2. Redistributions in binary form must reproduce the above copyright
                     13:  *    notice, this list of conditions and the following disclaimer in the
                     14:  *    documentation and/or other materials provided with the distribution.
                     15:  * 3. All advertising materials mentioning features or use of this software
                     16:  *    must display the following acknowledgement:
                     17:  *     This product includes software developed by the University of
                     18:  *     California, Berkeley and its contributors.
                     19:  * 4. Neither the name of the University nor the names of its contributors
                     20:  *    may be used to endorse or promote products derived from this software
                     21:  *    without specific prior written permission.
                     22:  *
                     23:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     24:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     25:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     26:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     27:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     28:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     29:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     30:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     31:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     32:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     33:  * SUCH DAMAGE.
                     34:  *
1.14      cgd        35:  *     @(#)ip_input.c  8.2 (Berkeley) 1/4/94
1.1       cgd        36:  */
                     37:
1.5       mycroft    38: #include <sys/param.h>
                     39: #include <sys/systm.h>
                     40: #include <sys/malloc.h>
                     41: #include <sys/mbuf.h>
                     42: #include <sys/domain.h>
                     43: #include <sys/protosw.h>
                     44: #include <sys/socket.h>
                     45: #include <sys/errno.h>
                     46: #include <sys/time.h>
                     47: #include <sys/kernel.h>
1.1       cgd        48:
1.5       mycroft    49: #include <net/if.h>
                     50: #include <net/route.h>
1.1       cgd        51:
1.5       mycroft    52: #include <netinet/in.h>
                     53: #include <netinet/in_systm.h>
                     54: #include <netinet/ip.h>
                     55: #include <netinet/in_pcb.h>
                     56: #include <netinet/in_var.h>
                     57: #include <netinet/ip_var.h>
                     58: #include <netinet/ip_icmp.h>
1.1       cgd        59:
                     60: #ifndef        IPFORWARDING
                     61: #ifdef GATEWAY
                     62: #define        IPFORWARDING    1       /* forward IP packets not for us */
                     63: #else /* GATEWAY */
                     64: #define        IPFORWARDING    0       /* don't forward IP packets not for us */
                     65: #endif /* GATEWAY */
                     66: #endif /* IPFORWARDING */
                     67: #ifndef        IPSENDREDIRECTS
                     68: #define        IPSENDREDIRECTS 1
                     69: #endif
1.26      thorpej    70: #ifndef IPFORWSRCRT
                     71: #define        IPFORWSRCRT     1       /* allow source-routed packets */
                     72: #endif
1.27    ! thorpej    73: /*
        !            74:  * Note: DIRECTED_BROADCAST is handled this way so that previous
        !            75:  * configuration using this option will Just Work.
        !            76:  */
        !            77: #ifndef IPDIRECTEDBCAST
        !            78: #ifdef DIRECTED_BROADCAST
        !            79: #define IPDIRECTEDBCAST        1
        !            80: #else
        !            81: #define        IPDIRECTEDBCAST 0
        !            82: #endif /* DIRECTED_BROADCAST */
        !            83: #endif /* IPDIRECTEDBCAST */
1.1       cgd        84: int    ipforwarding = IPFORWARDING;
                     85: int    ipsendredirects = IPSENDREDIRECTS;
1.13      mycroft    86: int    ip_defttl = IPDEFTTL;
1.26      thorpej    87: int    ip_forwsrcrt = IPFORWSRCRT;
1.27    ! thorpej    88: int    ip_directedbcast = IPDIRECTEDBCAST;
1.1       cgd        89: #ifdef DIAGNOSTIC
                     90: int    ipprintfs = 0;
                     91: #endif
                     92:
                     93: extern struct domain inetdomain;
                     94: extern struct protosw inetsw[];
                     95: u_char ip_protox[IPPROTO_MAX];
                     96: int    ipqmaxlen = IFQ_MAXLEN;
1.22      mycroft    97: struct in_ifaddrhead in_ifaddr;
1.13      mycroft    98: struct ifqueue ipintrq;
1.1       cgd        99:
                    100: /*
                    101:  * We need to save the IP options in case a protocol wants to respond
                    102:  * to an incoming packet over the same route if the packet got here
                    103:  * using IP source routing.  This allows connection establishment and
                    104:  * maintenance when the remote end is on a network that is not known
                    105:  * to us.
                    106:  */
                    107: int    ip_nhops = 0;
                    108: static struct ip_srcrt {
                    109:        struct  in_addr dst;                    /* final destination */
                    110:        char    nop;                            /* one NOP to align */
                    111:        char    srcopt[IPOPT_OFFSET + 1];       /* OPTVAL, OLEN and OFFSET */
                    112:        struct  in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
                    113: } ip_srcrt;
                    114:
1.13      mycroft   115: static void save_rte __P((u_char *, struct in_addr));
1.1       cgd       116: /*
                    117:  * IP initialization: fill in IP protocol switch table.
                    118:  * All protocols not implemented in kernel go to raw IP protocol handler.
                    119:  */
1.8       mycroft   120: void
1.1       cgd       121: ip_init()
                    122: {
                    123:        register struct protosw *pr;
                    124:        register int i;
                    125:
                    126:        pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
                    127:        if (pr == 0)
                    128:                panic("ip_init");
                    129:        for (i = 0; i < IPPROTO_MAX; i++)
                    130:                ip_protox[i] = pr - inetsw;
                    131:        for (pr = inetdomain.dom_protosw;
                    132:            pr < inetdomain.dom_protoswNPROTOSW; pr++)
                    133:                if (pr->pr_domain->dom_family == PF_INET &&
                    134:                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
                    135:                        ip_protox[pr->pr_protocol] = pr - inetsw;
1.25      cgd       136:        LIST_INIT(&ipq);
1.1       cgd       137:        ip_id = time.tv_sec & 0xffff;
                    138:        ipintrq.ifq_maxlen = ipqmaxlen;
1.22      mycroft   139:        TAILQ_INIT(&in_ifaddr);
1.1       cgd       140: }
                    141:
                    142: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    143: struct route ipforward_rt;
                    144:
                    145: /*
                    146:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    147:  * try to reassemble.  Process options.  Pass to next level.
                    148:  */
1.8       mycroft   149: void
1.1       cgd       150: ipintr()
                    151: {
                    152:        register struct ip *ip;
                    153:        register struct mbuf *m;
                    154:        register struct ipq *fp;
                    155:        register struct in_ifaddr *ia;
1.25      cgd       156:        struct ipqent *ipqe;
                    157:        int hlen, mff, s;
1.1       cgd       158:
                    159: next:
                    160:        /*
                    161:         * Get next datagram off input queue and get IP header
                    162:         * in first mbuf.
                    163:         */
                    164:        s = splimp();
                    165:        IF_DEQUEUE(&ipintrq, m);
                    166:        splx(s);
1.13      mycroft   167:        if (m == 0)
1.1       cgd       168:                return;
                    169: #ifdef DIAGNOSTIC
                    170:        if ((m->m_flags & M_PKTHDR) == 0)
                    171:                panic("ipintr no HDR");
                    172: #endif
                    173:        /*
                    174:         * If no IP addresses have been set yet but the interfaces
                    175:         * are receiving, can't do anything with incoming packets yet.
                    176:         */
1.22      mycroft   177:        if (in_ifaddr.tqh_first == 0)
1.1       cgd       178:                goto bad;
                    179:        ipstat.ips_total++;
                    180:        if (m->m_len < sizeof (struct ip) &&
                    181:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    182:                ipstat.ips_toosmall++;
                    183:                goto next;
                    184:        }
                    185:        ip = mtod(m, struct ip *);
1.13      mycroft   186:        if (ip->ip_v != IPVERSION) {
                    187:                ipstat.ips_badvers++;
                    188:                goto bad;
                    189:        }
1.1       cgd       190:        hlen = ip->ip_hl << 2;
                    191:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    192:                ipstat.ips_badhlen++;
                    193:                goto bad;
                    194:        }
                    195:        if (hlen > m->m_len) {
                    196:                if ((m = m_pullup(m, hlen)) == 0) {
                    197:                        ipstat.ips_badhlen++;
                    198:                        goto next;
                    199:                }
                    200:                ip = mtod(m, struct ip *);
                    201:        }
                    202:        if (ip->ip_sum = in_cksum(m, hlen)) {
                    203:                ipstat.ips_badsum++;
                    204:                goto bad;
                    205:        }
                    206:
                    207:        /*
                    208:         * Convert fields to host representation.
                    209:         */
                    210:        NTOHS(ip->ip_len);
                    211:        if (ip->ip_len < hlen) {
                    212:                ipstat.ips_badlen++;
                    213:                goto bad;
                    214:        }
                    215:        NTOHS(ip->ip_id);
                    216:        NTOHS(ip->ip_off);
                    217:
                    218:        /*
                    219:         * Check that the amount of data in the buffers
                    220:         * is as at least much as the IP header would have us expect.
                    221:         * Trim mbufs if longer than we expect.
                    222:         * Drop packet if shorter than we expect.
                    223:         */
                    224:        if (m->m_pkthdr.len < ip->ip_len) {
                    225:                ipstat.ips_tooshort++;
                    226:                goto bad;
                    227:        }
                    228:        if (m->m_pkthdr.len > ip->ip_len) {
                    229:                if (m->m_len == m->m_pkthdr.len) {
                    230:                        m->m_len = ip->ip_len;
                    231:                        m->m_pkthdr.len = ip->ip_len;
                    232:                } else
                    233:                        m_adj(m, ip->ip_len - m->m_pkthdr.len);
                    234:        }
                    235:
                    236:        /*
                    237:         * Process options and, if not destined for us,
                    238:         * ship it on.  ip_dooptions returns 1 when an
                    239:         * error was detected (causing an icmp message
                    240:         * to be sent and the original packet to be freed).
                    241:         */
                    242:        ip_nhops = 0;           /* for source routed packets */
                    243:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    244:                goto next;
                    245:
                    246:        /*
                    247:         * Check our list of addresses, to see if the packet is for us.
                    248:         */
1.22      mycroft   249:        for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
1.20      mycroft   250:                if (ip->ip_dst.s_addr == ia->ia_addr.sin_addr.s_addr)
1.1       cgd       251:                        goto ours;
1.27    ! thorpej   252:                if (((ip_directedbcast == 0) || (ip_directedbcast &&
        !           253:                    ia->ia_ifp == m->m_pkthdr.rcvif)) &&
1.1       cgd       254:                    (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.20      mycroft   255:                        if (ip->ip_dst.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
                    256:                            ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr ||
                    257:                            /*
                    258:                             * Look for all-0's host part (old broadcast addr),
                    259:                             * either for subnet or net.
                    260:                             */
                    261:                            ip->ip_dst.s_addr == ia->ia_subnet ||
1.18      mycroft   262:                            ip->ip_dst.s_addr == ia->ia_net)
1.1       cgd       263:                                goto ours;
                    264:                }
                    265:        }
1.18      mycroft   266:        if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4       hpeyerl   267:                struct in_multi *inm;
                    268: #ifdef MROUTING
                    269:                extern struct socket *ip_mrouter;
1.10      brezak    270:
                    271:                if (m->m_flags & M_EXT) {
                    272:                        if ((m = m_pullup(m, hlen)) == 0) {
                    273:                                ipstat.ips_toosmall++;
                    274:                                goto next;
                    275:                        }
                    276:                        ip = mtod(m, struct ip *);
                    277:                }
1.4       hpeyerl   278:
                    279:                if (ip_mrouter) {
                    280:                        /*
                    281:                         * If we are acting as a multicast router, all
                    282:                         * incoming multicast packets are passed to the
                    283:                         * kernel-level multicast forwarding function.
                    284:                         * The packet is returned (relatively) intact; if
                    285:                         * ip_mforward() returns a non-zero value, the packet
                    286:                         * must be discarded, else it may be accepted below.
                    287:                         *
                    288:                         * (The IP ident field is put in the same byte order
                    289:                         * as expected when ip_mforward() is called from
                    290:                         * ip_output().)
                    291:                         */
                    292:                        ip->ip_id = htons(ip->ip_id);
1.13      mycroft   293:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    294:                                ipstat.ips_cantforward++;
1.4       hpeyerl   295:                                m_freem(m);
                    296:                                goto next;
                    297:                        }
                    298:                        ip->ip_id = ntohs(ip->ip_id);
                    299:
                    300:                        /*
                    301:                         * The process-level routing demon needs to receive
                    302:                         * all multicast IGMP packets, whether or not this
                    303:                         * host belongs to their destination groups.
                    304:                         */
                    305:                        if (ip->ip_p == IPPROTO_IGMP)
                    306:                                goto ours;
1.13      mycroft   307:                        ipstat.ips_forward++;
1.4       hpeyerl   308:                }
                    309: #endif
                    310:                /*
                    311:                 * See if we belong to the destination multicast group on the
                    312:                 * arrival interface.
                    313:                 */
                    314:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    315:                if (inm == NULL) {
1.13      mycroft   316:                        ipstat.ips_cantforward++;
1.4       hpeyerl   317:                        m_freem(m);
                    318:                        goto next;
                    319:                }
                    320:                goto ours;
                    321:        }
1.19      mycroft   322:        if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
                    323:            ip->ip_dst.s_addr == INADDR_ANY)
1.1       cgd       324:                goto ours;
                    325:
                    326:        /*
                    327:         * Not for us; forward if possible and desirable.
                    328:         */
                    329:        if (ipforwarding == 0) {
                    330:                ipstat.ips_cantforward++;
                    331:                m_freem(m);
                    332:        } else
                    333:                ip_forward(m, 0);
                    334:        goto next;
                    335:
                    336: ours:
                    337:        /*
                    338:         * If offset or IP_MF are set, must reassemble.
                    339:         * Otherwise, nothing need be done.
                    340:         * (We could look in the reassembly queue to see
                    341:         * if the packet was previously fragmented,
                    342:         * but it's not worth the time; just let them time out.)
                    343:         */
                    344:        if (ip->ip_off &~ IP_DF) {
                    345:                if (m->m_flags & M_EXT) {               /* XXX */
                    346:                        if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
                    347:                                ipstat.ips_toosmall++;
                    348:                                goto next;
                    349:                        }
                    350:                        ip = mtod(m, struct ip *);
                    351:                }
                    352:                /*
                    353:                 * Look for queue of fragments
                    354:                 * of this datagram.
                    355:                 */
1.25      cgd       356:                for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1       cgd       357:                        if (ip->ip_id == fp->ipq_id &&
                    358:                            ip->ip_src.s_addr == fp->ipq_src.s_addr &&
                    359:                            ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
                    360:                            ip->ip_p == fp->ipq_p)
                    361:                                goto found;
                    362:                fp = 0;
                    363: found:
                    364:
                    365:                /*
                    366:                 * Adjust ip_len to not reflect header,
1.25      cgd       367:                 * set ipqe_mff if more fragments are expected,
1.1       cgd       368:                 * convert offset of this to bytes.
                    369:                 */
                    370:                ip->ip_len -= hlen;
1.25      cgd       371:                mff = (ip->ip_off & IP_MF) != 0;
                    372:                if (mff) {
1.16      cgd       373:                        /*
                    374:                         * Make sure that fragments have a data length
                    375:                         * that's a non-zero multiple of 8 bytes.
                    376:                         */
1.17      cgd       377:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16      cgd       378:                                ipstat.ips_badfrags++;
                    379:                                goto bad;
                    380:                        }
                    381:                }
1.1       cgd       382:                ip->ip_off <<= 3;
                    383:
                    384:                /*
                    385:                 * If datagram marked as having more fragments
                    386:                 * or if this is not the first fragment,
                    387:                 * attempt reassembly; if it succeeds, proceed.
                    388:                 */
1.25      cgd       389:                if (mff || ip->ip_off) {
1.1       cgd       390:                        ipstat.ips_fragments++;
1.25      cgd       391:                        MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent),
                    392:                            M_IPQ, M_NOWAIT);
                    393:                        if (ipqe == NULL) {
                    394:                                ipstat.ips_rcvmemdrop++;
                    395:                                goto bad;
                    396:                        }
                    397:                        ipqe->ipqe_mff = mff;
                    398:                        ipqe->ipqe_ip = ip;
                    399:                        ip = ip_reass(ipqe, fp);
1.1       cgd       400:                        if (ip == 0)
                    401:                                goto next;
1.13      mycroft   402:                        ipstat.ips_reassembled++;
1.1       cgd       403:                        m = dtom(ip);
                    404:                } else
                    405:                        if (fp)
                    406:                                ip_freef(fp);
                    407:        } else
                    408:                ip->ip_len -= hlen;
                    409:
                    410:        /*
                    411:         * Switch out to protocol's input routine.
                    412:         */
                    413:        ipstat.ips_delivered++;
                    414:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    415:        goto next;
                    416: bad:
                    417:        m_freem(m);
                    418:        goto next;
                    419: }
                    420:
                    421: /*
                    422:  * Take incoming datagram fragment and try to
                    423:  * reassemble it into whole datagram.  If a chain for
                    424:  * reassembly of this datagram already exists, then it
                    425:  * is given as fp; otherwise have to make a chain.
                    426:  */
                    427: struct ip *
1.25      cgd       428: ip_reass(ipqe, fp)
                    429:        register struct ipqent *ipqe;
1.1       cgd       430:        register struct ipq *fp;
                    431: {
1.25      cgd       432:        register struct mbuf *m = dtom(ipqe->ipqe_ip);
                    433:        register struct ipqent *nq, *p, *q;
                    434:        struct ip *ip;
1.1       cgd       435:        struct mbuf *t;
1.25      cgd       436:        int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1       cgd       437:        int i, next;
                    438:
                    439:        /*
                    440:         * Presence of header sizes in mbufs
                    441:         * would confuse code below.
                    442:         */
                    443:        m->m_data += hlen;
                    444:        m->m_len -= hlen;
                    445:
                    446:        /*
                    447:         * If first fragment to arrive, create a reassembly queue.
                    448:         */
                    449:        if (fp == 0) {
                    450:                if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
                    451:                        goto dropfrag;
                    452:                fp = mtod(t, struct ipq *);
1.25      cgd       453:                LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1       cgd       454:                fp->ipq_ttl = IPFRAGTTL;
1.25      cgd       455:                fp->ipq_p = ipqe->ipqe_ip->ip_p;
                    456:                fp->ipq_id = ipqe->ipqe_ip->ip_id;
                    457:                LIST_INIT(&fp->ipq_fragq);
                    458:                fp->ipq_src = ipqe->ipqe_ip->ip_src;
                    459:                fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
                    460:                p = NULL;
1.1       cgd       461:                goto insert;
                    462:        }
                    463:
                    464:        /*
                    465:         * Find a segment which begins after this one does.
                    466:         */
1.25      cgd       467:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    468:            p = q, q = q->ipqe_q.le_next)
                    469:                if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1       cgd       470:                        break;
                    471:
                    472:        /*
                    473:         * If there is a preceding segment, it may provide some of
                    474:         * our data already.  If so, drop the data from the incoming
                    475:         * segment.  If it provides all of our data, drop us.
                    476:         */
1.25      cgd       477:        if (p != NULL) {
                    478:                i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
                    479:                    ipqe->ipqe_ip->ip_off;
1.1       cgd       480:                if (i > 0) {
1.25      cgd       481:                        if (i >= ipqe->ipqe_ip->ip_len)
1.1       cgd       482:                                goto dropfrag;
1.25      cgd       483:                        m_adj(dtom(ipqe->ipqe_ip), i);
                    484:                        ipqe->ipqe_ip->ip_off += i;
                    485:                        ipqe->ipqe_ip->ip_len -= i;
1.1       cgd       486:                }
                    487:        }
                    488:
                    489:        /*
                    490:         * While we overlap succeeding segments trim them or,
                    491:         * if they are completely covered, dequeue them.
                    492:         */
1.25      cgd       493:        for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
                    494:            q->ipqe_ip->ip_off; q = nq) {
                    495:                i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
                    496:                    q->ipqe_ip->ip_off;
                    497:                if (i < q->ipqe_ip->ip_len) {
                    498:                        q->ipqe_ip->ip_len -= i;
                    499:                        q->ipqe_ip->ip_off += i;
                    500:                        m_adj(dtom(q->ipqe_ip), i);
1.1       cgd       501:                        break;
                    502:                }
1.25      cgd       503:                nq = q->ipqe_q.le_next;
                    504:                m_freem(dtom(q->ipqe_ip));
                    505:                LIST_REMOVE(q, ipqe_q);
                    506:                FREE(q, M_IPQ);
1.1       cgd       507:        }
                    508:
                    509: insert:
                    510:        /*
                    511:         * Stick new segment in its place;
                    512:         * check for complete reassembly.
                    513:         */
1.25      cgd       514:        if (p == NULL) {
                    515:                LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
                    516:        } else {
                    517:                LIST_INSERT_AFTER(p, ipqe, ipqe_q);
                    518:        }
1.1       cgd       519:        next = 0;
1.25      cgd       520:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    521:            p = q, q = q->ipqe_q.le_next) {
                    522:                if (q->ipqe_ip->ip_off != next)
1.1       cgd       523:                        return (0);
1.25      cgd       524:                next += q->ipqe_ip->ip_len;
1.1       cgd       525:        }
1.25      cgd       526:        if (p->ipqe_mff)
1.1       cgd       527:                return (0);
                    528:
                    529:        /*
                    530:         * Reassembly is complete; concatenate fragments.
                    531:         */
1.25      cgd       532:        q = fp->ipq_fragq.lh_first;
                    533:        ip = q->ipqe_ip;
                    534:        m = dtom(q->ipqe_ip);
1.1       cgd       535:        t = m->m_next;
                    536:        m->m_next = 0;
                    537:        m_cat(m, t);
1.25      cgd       538:        nq = q->ipqe_q.le_next;
                    539:        FREE(q, M_IPQ);
                    540:        for (q = nq; q != NULL; q = nq) {
                    541:                t = dtom(q->ipqe_ip);
                    542:                nq = q->ipqe_q.le_next;
                    543:                FREE(q, M_IPQ);
1.1       cgd       544:                m_cat(m, t);
                    545:        }
                    546:
                    547:        /*
                    548:         * Create header for new ip packet by
                    549:         * modifying header of first packet;
                    550:         * dequeue and discard fragment reassembly header.
                    551:         * Make header visible.
                    552:         */
                    553:        ip->ip_len = next;
1.25      cgd       554:        ip->ip_src = fp->ipq_src;
                    555:        ip->ip_dst = fp->ipq_dst;
                    556:        LIST_REMOVE(fp, ipq_q);
1.1       cgd       557:        (void) m_free(dtom(fp));
                    558:        m->m_len += (ip->ip_hl << 2);
                    559:        m->m_data -= (ip->ip_hl << 2);
                    560:        /* some debugging cruft by sklower, below, will go away soon */
                    561:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
                    562:                register int plen = 0;
                    563:                for (t = m; m; m = m->m_next)
                    564:                        plen += m->m_len;
                    565:                t->m_pkthdr.len = plen;
                    566:        }
1.25      cgd       567:        return (ip);
1.1       cgd       568:
                    569: dropfrag:
                    570:        ipstat.ips_fragdropped++;
                    571:        m_freem(m);
1.25      cgd       572:        FREE(ipqe, M_IPQ);
1.1       cgd       573:        return (0);
                    574: }
                    575:
                    576: /*
                    577:  * Free a fragment reassembly header and all
                    578:  * associated datagrams.
                    579:  */
1.8       mycroft   580: void
1.1       cgd       581: ip_freef(fp)
                    582:        struct ipq *fp;
                    583: {
1.25      cgd       584:        register struct ipqent *q, *p;
1.1       cgd       585:
1.25      cgd       586:        for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
                    587:                p = q->ipqe_q.le_next;
                    588:                m_freem(dtom(q->ipqe_ip));
                    589:                LIST_REMOVE(q, ipqe_q);
                    590:                FREE(q, M_IPQ);
1.1       cgd       591:        }
1.25      cgd       592:        LIST_REMOVE(fp, ipq_q);
1.1       cgd       593:        (void) m_free(dtom(fp));
                    594: }
                    595:
                    596: /*
                    597:  * IP timer processing;
                    598:  * if a timer expires on a reassembly
                    599:  * queue, discard it.
                    600:  */
1.8       mycroft   601: void
1.1       cgd       602: ip_slowtimo()
                    603: {
1.25      cgd       604:        register struct ipq *fp, *nfp;
1.24      mycroft   605:        int s = splsoftnet();
1.1       cgd       606:
1.25      cgd       607:        for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
                    608:                nfp = fp->ipq_q.le_next;
                    609:                if (--fp->ipq_ttl == 0) {
1.1       cgd       610:                        ipstat.ips_fragtimeout++;
1.25      cgd       611:                        ip_freef(fp);
1.1       cgd       612:                }
                    613:        }
                    614:        splx(s);
                    615: }
                    616:
                    617: /*
                    618:  * Drain off all datagram fragments.
                    619:  */
1.8       mycroft   620: void
1.1       cgd       621: ip_drain()
                    622: {
                    623:
1.25      cgd       624:        while (ipq.lh_first != NULL) {
1.1       cgd       625:                ipstat.ips_fragdropped++;
1.25      cgd       626:                ip_freef(ipq.lh_first);
1.1       cgd       627:        }
                    628: }
                    629:
                    630: /*
                    631:  * Do option processing on a datagram,
                    632:  * possibly discarding it if bad options are encountered,
                    633:  * or forwarding it if source-routed.
                    634:  * Returns 1 if packet has been forwarded/freed,
                    635:  * 0 if the packet should be processed further.
                    636:  */
1.8       mycroft   637: int
1.1       cgd       638: ip_dooptions(m)
                    639:        struct mbuf *m;
                    640: {
                    641:        register struct ip *ip = mtod(m, struct ip *);
                    642:        register u_char *cp;
                    643:        register struct ip_timestamp *ipt;
                    644:        register struct in_ifaddr *ia;
                    645:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13      mycroft   646:        struct in_addr *sin, dst;
1.1       cgd       647:        n_time ntime;
                    648:
1.13      mycroft   649:        dst = ip->ip_dst;
1.1       cgd       650:        cp = (u_char *)(ip + 1);
                    651:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    652:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    653:                opt = cp[IPOPT_OPTVAL];
                    654:                if (opt == IPOPT_EOL)
                    655:                        break;
                    656:                if (opt == IPOPT_NOP)
                    657:                        optlen = 1;
                    658:                else {
                    659:                        optlen = cp[IPOPT_OLEN];
                    660:                        if (optlen <= 0 || optlen > cnt) {
                    661:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    662:                                goto bad;
                    663:                        }
                    664:                }
                    665:                switch (opt) {
                    666:
                    667:                default:
                    668:                        break;
                    669:
                    670:                /*
                    671:                 * Source routing with record.
                    672:                 * Find interface with current destination address.
                    673:                 * If none on this machine then drop if strictly routed,
                    674:                 * or do nothing if loosely routed.
                    675:                 * Record interface address and bring up next address
                    676:                 * component.  If strictly routed make sure next
                    677:                 * address is on directly accessible net.
                    678:                 */
                    679:                case IPOPT_LSRR:
                    680:                case IPOPT_SSRR:
                    681:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    682:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    683:                                goto bad;
                    684:                        }
                    685:                        ipaddr.sin_addr = ip->ip_dst;
1.19      mycroft   686:                        ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1       cgd       687:                        if (ia == 0) {
                    688:                                if (opt == IPOPT_SSRR) {
                    689:                                        type = ICMP_UNREACH;
                    690:                                        code = ICMP_UNREACH_SRCFAIL;
                    691:                                        goto bad;
                    692:                                }
                    693:                                /*
                    694:                                 * Loose routing, and not at next destination
                    695:                                 * yet; nothing to do except forward.
                    696:                                 */
                    697:                                break;
                    698:                        }
                    699:                        off--;                  /* 0 origin */
                    700:                        if (off > optlen - sizeof(struct in_addr)) {
                    701:                                /*
                    702:                                 * End of source route.  Should be for us.
                    703:                                 */
                    704:                                save_rte(cp, ip->ip_src);
                    705:                                break;
                    706:                        }
                    707:                        /*
                    708:                         * locate outgoing interface
                    709:                         */
                    710:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    711:                            sizeof(ipaddr.sin_addr));
                    712:                        if (opt == IPOPT_SSRR) {
                    713: #define        INA     struct in_ifaddr *
                    714: #define        SA      struct sockaddr *
                    715:                            if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
1.13      mycroft   716:                                ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1.1       cgd       717:                        } else
                    718:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    719:                        if (ia == 0) {
                    720:                                type = ICMP_UNREACH;
                    721:                                code = ICMP_UNREACH_SRCFAIL;
                    722:                                goto bad;
                    723:                        }
                    724:                        ip->ip_dst = ipaddr.sin_addr;
1.20      mycroft   725:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       726:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    727:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft   728:                        /*
                    729:                         * Let ip_intr's mcast routing check handle mcast pkts
                    730:                         */
1.18      mycroft   731:                        forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1       cgd       732:                        break;
                    733:
                    734:                case IPOPT_RR:
                    735:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    736:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    737:                                goto bad;
                    738:                        }
                    739:                        /*
                    740:                         * If no space remains, ignore.
                    741:                         */
                    742:                        off--;                  /* 0 origin */
                    743:                        if (off > optlen - sizeof(struct in_addr))
                    744:                                break;
                    745:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    746:                            sizeof(ipaddr.sin_addr));
                    747:                        /*
                    748:                         * locate outgoing interface; if we're the destination,
                    749:                         * use the incoming interface (should be same).
                    750:                         */
                    751:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    752:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    753:                                type = ICMP_UNREACH;
                    754:                                code = ICMP_UNREACH_HOST;
                    755:                                goto bad;
                    756:                        }
1.20      mycroft   757:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       758:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    759:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    760:                        break;
                    761:
                    762:                case IPOPT_TS:
                    763:                        code = cp - (u_char *)ip;
                    764:                        ipt = (struct ip_timestamp *)cp;
                    765:                        if (ipt->ipt_len < 5)
                    766:                                goto bad;
1.15      cgd       767:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1       cgd       768:                                if (++ipt->ipt_oflw == 0)
                    769:                                        goto bad;
                    770:                                break;
                    771:                        }
                    772:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    773:                        switch (ipt->ipt_flg) {
                    774:
                    775:                        case IPOPT_TS_TSONLY:
                    776:                                break;
                    777:
                    778:                        case IPOPT_TS_TSANDADDR:
                    779:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    780:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    781:                                        goto bad;
1.13      mycroft   782:                                ipaddr.sin_addr = dst;
                    783:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
                    784:                                                            m->m_pkthdr.rcvif);
                    785:                                if (ia == 0)
                    786:                                        continue;
1.20      mycroft   787:                                bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       788:                                    (caddr_t)sin, sizeof(struct in_addr));
                    789:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    790:                                break;
                    791:
                    792:                        case IPOPT_TS_PRESPEC:
                    793:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    794:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    795:                                        goto bad;
                    796:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    797:                                    sizeof(struct in_addr));
                    798:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    799:                                        continue;
                    800:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    801:                                break;
                    802:
                    803:                        default:
                    804:                                goto bad;
                    805:                        }
                    806:                        ntime = iptime();
                    807:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    808:                            sizeof(n_time));
                    809:                        ipt->ipt_ptr += sizeof(n_time);
                    810:                }
                    811:        }
                    812:        if (forward) {
1.26      thorpej   813:                if (ip_forwsrcrt == 0) {
                    814:                        type = ICMP_UNREACH;
                    815:                        code = ICMP_UNREACH_SRCFAIL;
                    816:                        goto bad;
                    817:                }
1.1       cgd       818:                ip_forward(m, 1);
                    819:                return (1);
1.13      mycroft   820:        }
                    821:        return (0);
1.1       cgd       822: bad:
1.13      mycroft   823:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
                    824:        icmp_error(m, type, code, 0, 0);
                    825:        ipstat.ips_badoptions++;
1.1       cgd       826:        return (1);
                    827: }
                    828:
                    829: /*
                    830:  * Given address of next destination (final or next hop),
                    831:  * return internet address info of interface to be used to get there.
                    832:  */
                    833: struct in_ifaddr *
                    834: ip_rtaddr(dst)
                    835:         struct in_addr dst;
                    836: {
                    837:        register struct sockaddr_in *sin;
                    838:
1.19      mycroft   839:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd       840:
                    841:        if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
                    842:                if (ipforward_rt.ro_rt) {
                    843:                        RTFREE(ipforward_rt.ro_rt);
                    844:                        ipforward_rt.ro_rt = 0;
                    845:                }
                    846:                sin->sin_family = AF_INET;
                    847:                sin->sin_len = sizeof(*sin);
                    848:                sin->sin_addr = dst;
                    849:
                    850:                rtalloc(&ipforward_rt);
                    851:        }
                    852:        if (ipforward_rt.ro_rt == 0)
                    853:                return ((struct in_ifaddr *)0);
1.19      mycroft   854:        return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1       cgd       855: }
                    856:
                    857: /*
                    858:  * Save incoming source route for use in replies,
                    859:  * to be picked up later by ip_srcroute if the receiver is interested.
                    860:  */
1.13      mycroft   861: void
1.1       cgd       862: save_rte(option, dst)
                    863:        u_char *option;
                    864:        struct in_addr dst;
                    865: {
                    866:        unsigned olen;
                    867:
                    868:        olen = option[IPOPT_OLEN];
                    869: #ifdef DIAGNOSTIC
                    870:        if (ipprintfs)
                    871:                printf("save_rte: olen %d\n", olen);
                    872: #endif
                    873:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    874:                return;
                    875:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    876:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    877:        ip_srcrt.dst = dst;
                    878: }
                    879:
                    880: /*
                    881:  * Retrieve incoming source route for use in replies,
                    882:  * in the same form used by setsockopt.
                    883:  * The first hop is placed before the options, will be removed later.
                    884:  */
                    885: struct mbuf *
                    886: ip_srcroute()
                    887: {
                    888:        register struct in_addr *p, *q;
                    889:        register struct mbuf *m;
                    890:
                    891:        if (ip_nhops == 0)
                    892:                return ((struct mbuf *)0);
                    893:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    894:        if (m == 0)
                    895:                return ((struct mbuf *)0);
                    896:
1.13      mycroft   897: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       898:
                    899:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    900:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    901:            OPTSIZ;
                    902: #ifdef DIAGNOSTIC
                    903:        if (ipprintfs)
                    904:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
                    905: #endif
                    906:
                    907:        /*
                    908:         * First save first hop for return route
                    909:         */
                    910:        p = &ip_srcrt.route[ip_nhops - 1];
                    911:        *(mtod(m, struct in_addr *)) = *p--;
                    912: #ifdef DIAGNOSTIC
                    913:        if (ipprintfs)
                    914:                printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr));
                    915: #endif
                    916:
                    917:        /*
                    918:         * Copy option fields and padding (nop) to mbuf.
                    919:         */
                    920:        ip_srcrt.nop = IPOPT_NOP;
                    921:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    922:        bcopy((caddr_t)&ip_srcrt.nop,
                    923:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    924:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    925:            sizeof(struct in_addr) + OPTSIZ);
                    926: #undef OPTSIZ
                    927:        /*
                    928:         * Record return path as an IP source route,
                    929:         * reversing the path (pointers are now aligned).
                    930:         */
                    931:        while (p >= ip_srcrt.route) {
                    932: #ifdef DIAGNOSTIC
                    933:                if (ipprintfs)
                    934:                        printf(" %lx", ntohl(q->s_addr));
                    935: #endif
                    936:                *q++ = *p--;
                    937:        }
                    938:        /*
                    939:         * Last hop goes to final destination.
                    940:         */
                    941:        *q = ip_srcrt.dst;
                    942: #ifdef DIAGNOSTIC
                    943:        if (ipprintfs)
                    944:                printf(" %lx\n", ntohl(q->s_addr));
                    945: #endif
                    946:        return (m);
                    947: }
                    948:
                    949: /*
                    950:  * Strip out IP options, at higher
                    951:  * level protocol in the kernel.
                    952:  * Second argument is buffer to which options
                    953:  * will be moved, and return value is their length.
                    954:  * XXX should be deleted; last arg currently ignored.
                    955:  */
1.8       mycroft   956: void
1.1       cgd       957: ip_stripoptions(m, mopt)
                    958:        register struct mbuf *m;
                    959:        struct mbuf *mopt;
                    960: {
                    961:        register int i;
                    962:        struct ip *ip = mtod(m, struct ip *);
                    963:        register caddr_t opts;
                    964:        int olen;
                    965:
                    966:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                    967:        opts = (caddr_t)(ip + 1);
                    968:        i = m->m_len - (sizeof (struct ip) + olen);
                    969:        bcopy(opts  + olen, opts, (unsigned)i);
                    970:        m->m_len -= olen;
                    971:        if (m->m_flags & M_PKTHDR)
                    972:                m->m_pkthdr.len -= olen;
                    973:        ip->ip_hl = sizeof(struct ip) >> 2;
                    974: }
                    975:
1.23      mycroft   976: int inetctlerrmap[PRC_NCMDS] = {
1.1       cgd       977:        0,              0,              0,              0,
                    978:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                    979:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                    980:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                    981:        0,              0,              0,              0,
                    982:        ENOPROTOOPT
                    983: };
                    984:
                    985: /*
                    986:  * Forward a packet.  If some error occurs return the sender
                    987:  * an icmp packet.  Note we can't always generate a meaningful
                    988:  * icmp message because icmp doesn't have a large enough repertoire
                    989:  * of codes and types.
                    990:  *
                    991:  * If not forwarding, just drop the packet.  This could be confusing
                    992:  * if ipforwarding was zero but some routing protocol was advancing
                    993:  * us as a gateway to somewhere.  However, we must let the routing
                    994:  * protocol deal with that.
                    995:  *
                    996:  * The srcrt parameter indicates whether the packet is being forwarded
                    997:  * via a source route.
                    998:  */
1.13      mycroft   999: void
1.1       cgd      1000: ip_forward(m, srcrt)
                   1001:        struct mbuf *m;
                   1002:        int srcrt;
                   1003: {
                   1004:        register struct ip *ip = mtod(m, struct ip *);
                   1005:        register struct sockaddr_in *sin;
                   1006:        register struct rtentry *rt;
                   1007:        int error, type = 0, code;
                   1008:        struct mbuf *mcopy;
1.13      mycroft  1009:        n_long dest;
                   1010:        struct ifnet *destifp;
1.1       cgd      1011:
1.13      mycroft  1012:        dest = 0;
1.1       cgd      1013: #ifdef DIAGNOSTIC
                   1014:        if (ipprintfs)
                   1015:                printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
                   1016:                        ip->ip_dst, ip->ip_ttl);
                   1017: #endif
                   1018:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1019:                ipstat.ips_cantforward++;
                   1020:                m_freem(m);
                   1021:                return;
                   1022:        }
                   1023:        HTONS(ip->ip_id);
                   1024:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1025:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1026:                return;
                   1027:        }
                   1028:        ip->ip_ttl -= IPTTLDEC;
                   1029:
1.19      mycroft  1030:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1031:        if ((rt = ipforward_rt.ro_rt) == 0 ||
                   1032:            ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
                   1033:                if (ipforward_rt.ro_rt) {
                   1034:                        RTFREE(ipforward_rt.ro_rt);
                   1035:                        ipforward_rt.ro_rt = 0;
                   1036:                }
                   1037:                sin->sin_family = AF_INET;
                   1038:                sin->sin_len = sizeof(*sin);
                   1039:                sin->sin_addr = ip->ip_dst;
                   1040:
                   1041:                rtalloc(&ipforward_rt);
                   1042:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1043:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1044:                        return;
                   1045:                }
                   1046:                rt = ipforward_rt.ro_rt;
                   1047:        }
                   1048:
                   1049:        /*
                   1050:         * Save at most 64 bytes of the packet in case
                   1051:         * we need to generate an ICMP message to the src.
                   1052:         */
                   1053:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
                   1054:
                   1055:        /*
                   1056:         * If forwarding packet using same interface that it came in on,
                   1057:         * perhaps should send a redirect to sender to shortcut a hop.
                   1058:         * Only send redirect if source is sending directly to us,
                   1059:         * and if packet was not source routed (or has any options).
                   1060:         * Also, don't send redirect if forwarding using a default route
                   1061:         * or a route modified by a redirect.
                   1062:         */
                   1063:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1064:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
                   1065:            satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
                   1066:            ipsendredirects && !srcrt) {
1.19      mycroft  1067:                if (rt->rt_ifa &&
                   1068:                    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
                   1069:                    ifatoia(rt->rt_ifa)->ia_subnet) {
1.1       cgd      1070:                    if (rt->rt_flags & RTF_GATEWAY)
1.13      mycroft  1071:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1072:                    else
1.13      mycroft  1073:                        dest = ip->ip_dst.s_addr;
                   1074:                    /* Router requirements says to only send host redirects */
1.1       cgd      1075:                    type = ICMP_REDIRECT;
1.13      mycroft  1076:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1077: #ifdef DIAGNOSTIC
                   1078:                    if (ipprintfs)
1.15      cgd      1079:                        printf("redirect (%d) to %lx\n", code, (u_int32_t)dest);
1.1       cgd      1080: #endif
                   1081:                }
                   1082:        }
                   1083:
1.27    ! thorpej  1084:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
        !          1085:            (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0);
1.1       cgd      1086:        if (error)
                   1087:                ipstat.ips_cantforward++;
                   1088:        else {
                   1089:                ipstat.ips_forward++;
                   1090:                if (type)
                   1091:                        ipstat.ips_redirectsent++;
                   1092:                else {
                   1093:                        if (mcopy)
                   1094:                                m_freem(mcopy);
                   1095:                        return;
                   1096:                }
                   1097:        }
                   1098:        if (mcopy == NULL)
                   1099:                return;
1.13      mycroft  1100:        destifp = NULL;
                   1101:
1.1       cgd      1102:        switch (error) {
                   1103:
                   1104:        case 0:                         /* forwarded, but need redirect */
                   1105:                /* type, code set above */
                   1106:                break;
                   1107:
                   1108:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1109:        case EHOSTUNREACH:
                   1110:        case ENETDOWN:
                   1111:        case EHOSTDOWN:
                   1112:        default:
                   1113:                type = ICMP_UNREACH;
                   1114:                code = ICMP_UNREACH_HOST;
                   1115:                break;
                   1116:
                   1117:        case EMSGSIZE:
                   1118:                type = ICMP_UNREACH;
                   1119:                code = ICMP_UNREACH_NEEDFRAG;
1.13      mycroft  1120:                if (ipforward_rt.ro_rt)
                   1121:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1122:                ipstat.ips_cantfrag++;
                   1123:                break;
                   1124:
                   1125:        case ENOBUFS:
                   1126:                type = ICMP_SOURCEQUENCH;
                   1127:                code = 0;
                   1128:                break;
                   1129:        }
1.13      mycroft  1130:        icmp_error(mcopy, type, code, dest, destifp);
                   1131: }
                   1132:
                   1133: int
                   1134: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1135:        int *name;
                   1136:        u_int namelen;
                   1137:        void *oldp;
                   1138:        size_t *oldlenp;
                   1139:        void *newp;
                   1140:        size_t newlen;
                   1141: {
1.26      thorpej  1142:        int temp;
                   1143:
1.13      mycroft  1144:        /* All sysctl names at this level are terminal. */
                   1145:        if (namelen != 1)
                   1146:                return (ENOTDIR);
                   1147:
                   1148:        switch (name[0]) {
                   1149:        case IPCTL_FORWARDING:
                   1150:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
                   1151:        case IPCTL_SENDREDIRECTS:
                   1152:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1153:                        &ipsendredirects));
                   1154:        case IPCTL_DEFTTL:
                   1155:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
                   1156: #ifdef notyet
                   1157:        case IPCTL_DEFMTU:
                   1158:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
                   1159: #endif
1.26      thorpej  1160:        case IPCTL_FORWSRCRT:
                   1161:                /*
                   1162:                 * Don't allow this to change in a secure environment.
                   1163:                 */
                   1164:                if (securelevel > 0)
                   1165:                        return (EPERM);
                   1166:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1167:                    &ip_forwsrcrt));
1.27    ! thorpej  1168:        case IPCTL_DIRECTEDBCAST:
        !          1169:                return (sysctl_int(oldp, oldlenp, newp, newlen,
        !          1170:                    &ip_directedbcast));
1.13      mycroft  1171:        default:
                   1172:                return (EOPNOTSUPP);
                   1173:        }
                   1174:        /* NOTREACHED */
1.1       cgd      1175: }

CVSweb <webmaster@jp.NetBSD.org>