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Annotation of src/sys/netinet/ip_input.c, Revision 1.57

1.57    ! tls         1: /*     $NetBSD: ip_input.c,v 1.56 1998/01/28 02:36:10 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:  */
1.55      scottr     37:
                     38: #include "opt_mrouting.h"
1.1       cgd        39:
1.5       mycroft    40: #include <sys/param.h>
                     41: #include <sys/systm.h>
                     42: #include <sys/malloc.h>
                     43: #include <sys/mbuf.h>
                     44: #include <sys/domain.h>
                     45: #include <sys/protosw.h>
                     46: #include <sys/socket.h>
1.44      thorpej    47: #include <sys/socketvar.h>
1.5       mycroft    48: #include <sys/errno.h>
                     49: #include <sys/time.h>
                     50: #include <sys/kernel.h>
1.28      christos   51: #include <sys/proc.h>
                     52:
                     53: #include <vm/vm.h>
                     54: #include <sys/sysctl.h>
1.1       cgd        55:
1.5       mycroft    56: #include <net/if.h>
1.44      thorpej    57: #include <net/if_dl.h>
1.5       mycroft    58: #include <net/route.h>
1.45      mrg        59: #include <net/pfil.h>
1.1       cgd        60:
1.5       mycroft    61: #include <netinet/in.h>
                     62: #include <netinet/in_systm.h>
                     63: #include <netinet/ip.h>
                     64: #include <netinet/in_pcb.h>
                     65: #include <netinet/in_var.h>
                     66: #include <netinet/ip_var.h>
                     67: #include <netinet/ip_icmp.h>
1.44      thorpej    68:
1.1       cgd        69: #ifndef        IPFORWARDING
                     70: #ifdef GATEWAY
                     71: #define        IPFORWARDING    1       /* forward IP packets not for us */
                     72: #else /* GATEWAY */
                     73: #define        IPFORWARDING    0       /* don't forward IP packets not for us */
                     74: #endif /* GATEWAY */
                     75: #endif /* IPFORWARDING */
                     76: #ifndef        IPSENDREDIRECTS
                     77: #define        IPSENDREDIRECTS 1
                     78: #endif
1.26      thorpej    79: #ifndef IPFORWSRCRT
1.47      cjs        80: #define        IPFORWSRCRT     1       /* forward source-routed packets */
                     81: #endif
                     82: #ifndef IPALLOWSRCRT
1.48      mrg        83: #define        IPALLOWSRCRT    1       /* allow source-routed packets */
1.26      thorpej    84: #endif
1.53      kml        85: #ifndef IPMTUDISC
                     86: #define IPMTUDISC      0
                     87: #endif
                     88:
1.27      thorpej    89: /*
                     90:  * Note: DIRECTED_BROADCAST is handled this way so that previous
                     91:  * configuration using this option will Just Work.
                     92:  */
                     93: #ifndef IPDIRECTEDBCAST
                     94: #ifdef DIRECTED_BROADCAST
                     95: #define IPDIRECTEDBCAST        1
                     96: #else
                     97: #define        IPDIRECTEDBCAST 0
                     98: #endif /* DIRECTED_BROADCAST */
                     99: #endif /* IPDIRECTEDBCAST */
1.1       cgd       100: int    ipforwarding = IPFORWARDING;
                    101: int    ipsendredirects = IPSENDREDIRECTS;
1.13      mycroft   102: int    ip_defttl = IPDEFTTL;
1.26      thorpej   103: int    ip_forwsrcrt = IPFORWSRCRT;
1.27      thorpej   104: int    ip_directedbcast = IPDIRECTEDBCAST;
1.47      cjs       105: int    ip_allowsrcrt = IPALLOWSRCRT;
1.53      kml       106: int    ip_mtudisc = IPMTUDISC;
1.1       cgd       107: #ifdef DIAGNOSTIC
                    108: int    ipprintfs = 0;
                    109: #endif
                    110:
                    111: extern struct domain inetdomain;
                    112: extern struct protosw inetsw[];
                    113: u_char ip_protox[IPPROTO_MAX];
                    114: int    ipqmaxlen = IFQ_MAXLEN;
1.22      mycroft   115: struct in_ifaddrhead in_ifaddr;
1.57    ! tls       116: struct in_ifaddrhashhead *in_ifaddrhashtbl;
1.13      mycroft   117: struct ifqueue ipintrq;
1.1       cgd       118:
                    119: /*
                    120:  * We need to save the IP options in case a protocol wants to respond
                    121:  * to an incoming packet over the same route if the packet got here
                    122:  * using IP source routing.  This allows connection establishment and
                    123:  * maintenance when the remote end is on a network that is not known
                    124:  * to us.
                    125:  */
                    126: int    ip_nhops = 0;
                    127: static struct ip_srcrt {
                    128:        struct  in_addr dst;                    /* final destination */
                    129:        char    nop;                            /* one NOP to align */
                    130:        char    srcopt[IPOPT_OFFSET + 1];       /* OPTVAL, OLEN and OFFSET */
                    131:        struct  in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
                    132: } ip_srcrt;
                    133:
1.13      mycroft   134: static void save_rte __P((u_char *, struct in_addr));
1.35      mycroft   135:
1.1       cgd       136: /*
                    137:  * IP initialization: fill in IP protocol switch table.
                    138:  * All protocols not implemented in kernel go to raw IP protocol handler.
                    139:  */
1.8       mycroft   140: void
1.1       cgd       141: ip_init()
                    142: {
                    143:        register struct protosw *pr;
                    144:        register int i;
                    145:
                    146:        pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
                    147:        if (pr == 0)
                    148:                panic("ip_init");
                    149:        for (i = 0; i < IPPROTO_MAX; i++)
                    150:                ip_protox[i] = pr - inetsw;
                    151:        for (pr = inetdomain.dom_protosw;
                    152:            pr < inetdomain.dom_protoswNPROTOSW; pr++)
                    153:                if (pr->pr_domain->dom_family == PF_INET &&
                    154:                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
                    155:                        ip_protox[pr->pr_protocol] = pr - inetsw;
1.25      cgd       156:        LIST_INIT(&ipq);
1.1       cgd       157:        ip_id = time.tv_sec & 0xffff;
                    158:        ipintrq.ifq_maxlen = ipqmaxlen;
1.22      mycroft   159:        TAILQ_INIT(&in_ifaddr);
1.57    ! tls       160:        in_ifaddrhashtbl =
        !           161:            hashinit(IN_IFADDR_HASH_SIZE, M_IFADDR, M_WAITOK, &in_ifaddrhash);
1.1       cgd       162: }
                    163:
                    164: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    165: struct route ipforward_rt;
                    166:
                    167: /*
                    168:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    169:  * try to reassemble.  Process options.  Pass to next level.
                    170:  */
1.8       mycroft   171: void
1.1       cgd       172: ipintr()
                    173: {
1.33      mrg       174:        register struct ip *ip = NULL;
1.1       cgd       175:        register struct mbuf *m;
                    176:        register struct ipq *fp;
                    177:        register struct in_ifaddr *ia;
1.57    ! tls       178:        register struct ifaddr *ifa;
1.25      cgd       179:        struct ipqent *ipqe;
1.35      mycroft   180:        int hlen = 0, mff, len, s;
1.36      mrg       181: #ifdef PFIL_HOOKS
1.33      mrg       182:        struct packet_filter_hook *pfh;
                    183:        struct mbuf *m0;
1.43      mrg       184:        int rv;
1.36      mrg       185: #endif /* PFIL_HOOKS */
1.1       cgd       186:
                    187: next:
                    188:        /*
                    189:         * Get next datagram off input queue and get IP header
                    190:         * in first mbuf.
                    191:         */
                    192:        s = splimp();
                    193:        IF_DEQUEUE(&ipintrq, m);
                    194:        splx(s);
1.13      mycroft   195:        if (m == 0)
1.1       cgd       196:                return;
                    197: #ifdef DIAGNOSTIC
                    198:        if ((m->m_flags & M_PKTHDR) == 0)
                    199:                panic("ipintr no HDR");
                    200: #endif
                    201:        /*
                    202:         * If no IP addresses have been set yet but the interfaces
                    203:         * are receiving, can't do anything with incoming packets yet.
                    204:         */
1.22      mycroft   205:        if (in_ifaddr.tqh_first == 0)
1.1       cgd       206:                goto bad;
                    207:        ipstat.ips_total++;
                    208:        if (m->m_len < sizeof (struct ip) &&
                    209:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    210:                ipstat.ips_toosmall++;
                    211:                goto next;
                    212:        }
                    213:        ip = mtod(m, struct ip *);
1.13      mycroft   214:        if (ip->ip_v != IPVERSION) {
                    215:                ipstat.ips_badvers++;
                    216:                goto bad;
                    217:        }
1.1       cgd       218:        hlen = ip->ip_hl << 2;
                    219:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    220:                ipstat.ips_badhlen++;
                    221:                goto bad;
                    222:        }
                    223:        if (hlen > m->m_len) {
                    224:                if ((m = m_pullup(m, hlen)) == 0) {
                    225:                        ipstat.ips_badhlen++;
                    226:                        goto next;
                    227:                }
                    228:                ip = mtod(m, struct ip *);
                    229:        }
1.28      christos  230:        if ((ip->ip_sum = in_cksum(m, hlen)) != 0) {
1.1       cgd       231:                ipstat.ips_badsum++;
                    232:                goto bad;
                    233:        }
                    234:
                    235:        /*
                    236:         * Convert fields to host representation.
                    237:         */
                    238:        NTOHS(ip->ip_len);
                    239:        NTOHS(ip->ip_id);
                    240:        NTOHS(ip->ip_off);
1.35      mycroft   241:        len = ip->ip_len;
1.1       cgd       242:
                    243:        /*
                    244:         * Check that the amount of data in the buffers
                    245:         * is as at least much as the IP header would have us expect.
                    246:         * Trim mbufs if longer than we expect.
                    247:         * Drop packet if shorter than we expect.
                    248:         */
1.35      mycroft   249:        if (m->m_pkthdr.len < len) {
1.1       cgd       250:                ipstat.ips_tooshort++;
                    251:                goto bad;
                    252:        }
1.35      mycroft   253:        if (m->m_pkthdr.len > len) {
1.1       cgd       254:                if (m->m_len == m->m_pkthdr.len) {
1.35      mycroft   255:                        m->m_len = len;
                    256:                        m->m_pkthdr.len = len;
1.1       cgd       257:                } else
1.35      mycroft   258:                        m_adj(m, len - m->m_pkthdr.len);
1.1       cgd       259:        }
                    260:
1.36      mrg       261: #ifdef PFIL_HOOKS
1.33      mrg       262:        /*
                    263:         * Run through list of hooks for input packets.
                    264:         */
                    265:        m0 = m;
                    266:        for (pfh = pfil_hook_get(PFIL_IN); pfh; pfh = pfh->pfil_link.le_next)
                    267:                if (pfh->pfil_func) {
1.43      mrg       268:                        rv = pfh->pfil_func(ip, hlen, m->m_pkthdr.rcvif, 0, &m0);
                    269:                        if (rv)
1.40      veego     270:                                goto next;
1.49      christos  271:                        ip = mtod(m = m0, struct ip *);
1.33      mrg       272:                }
1.36      mrg       273: #endif /* PFIL_HOOKS */
1.33      mrg       274:
1.1       cgd       275:        /*
                    276:         * Process options and, if not destined for us,
                    277:         * ship it on.  ip_dooptions returns 1 when an
                    278:         * error was detected (causing an icmp message
                    279:         * to be sent and the original packet to be freed).
                    280:         */
                    281:        ip_nhops = 0;           /* for source routed packets */
                    282:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    283:                goto next;
                    284:
                    285:        /*
                    286:         * Check our list of addresses, to see if the packet is for us.
                    287:         */
1.57    ! tls       288:        INADDR_TO_IA(ip->ip_dst, ia);
        !           289:        if (ia != NULL) goto ours;
        !           290:        if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
        !           291:                for (ifa = m->m_pkthdr.rcvif->if_addrlist.tqh_first;
        !           292:                    ifa != NULL; ifa = ifa->ifa_list.tqe_next) {
        !           293:                        if (ifa->ifa_addr->sa_family != AF_INET) continue;
        !           294:                        ia = ifatoia(ifa);
1.35      mycroft   295:                        if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
                    296:                            in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
1.20      mycroft   297:                            /*
                    298:                             * Look for all-0's host part (old broadcast addr),
                    299:                             * either for subnet or net.
                    300:                             */
                    301:                            ip->ip_dst.s_addr == ia->ia_subnet ||
1.18      mycroft   302:                            ip->ip_dst.s_addr == ia->ia_net)
1.1       cgd       303:                                goto ours;
1.57    ! tls       304:                        /*
        !           305:                         * An interface with IP address zero accepts
        !           306:                         * all packets that arrive on that interface.
        !           307:                         */
        !           308:                        if (in_nullhost(ia->ia_addr.sin_addr))
        !           309:                                goto ours;
1.1       cgd       310:                }
                    311:        }
1.18      mycroft   312:        if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4       hpeyerl   313:                struct in_multi *inm;
                    314: #ifdef MROUTING
                    315:                extern struct socket *ip_mrouter;
1.10      brezak    316:
                    317:                if (m->m_flags & M_EXT) {
                    318:                        if ((m = m_pullup(m, hlen)) == 0) {
                    319:                                ipstat.ips_toosmall++;
                    320:                                goto next;
                    321:                        }
                    322:                        ip = mtod(m, struct ip *);
                    323:                }
1.4       hpeyerl   324:
                    325:                if (ip_mrouter) {
                    326:                        /*
                    327:                         * If we are acting as a multicast router, all
                    328:                         * incoming multicast packets are passed to the
                    329:                         * kernel-level multicast forwarding function.
                    330:                         * The packet is returned (relatively) intact; if
                    331:                         * ip_mforward() returns a non-zero value, the packet
                    332:                         * must be discarded, else it may be accepted below.
                    333:                         *
                    334:                         * (The IP ident field is put in the same byte order
                    335:                         * as expected when ip_mforward() is called from
                    336:                         * ip_output().)
                    337:                         */
                    338:                        ip->ip_id = htons(ip->ip_id);
1.13      mycroft   339:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    340:                                ipstat.ips_cantforward++;
1.4       hpeyerl   341:                                m_freem(m);
                    342:                                goto next;
                    343:                        }
                    344:                        ip->ip_id = ntohs(ip->ip_id);
                    345:
                    346:                        /*
                    347:                         * The process-level routing demon needs to receive
                    348:                         * all multicast IGMP packets, whether or not this
                    349:                         * host belongs to their destination groups.
                    350:                         */
                    351:                        if (ip->ip_p == IPPROTO_IGMP)
                    352:                                goto ours;
1.13      mycroft   353:                        ipstat.ips_forward++;
1.4       hpeyerl   354:                }
                    355: #endif
                    356:                /*
                    357:                 * See if we belong to the destination multicast group on the
                    358:                 * arrival interface.
                    359:                 */
                    360:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    361:                if (inm == NULL) {
1.13      mycroft   362:                        ipstat.ips_cantforward++;
1.4       hpeyerl   363:                        m_freem(m);
                    364:                        goto next;
                    365:                }
                    366:                goto ours;
                    367:        }
1.19      mycroft   368:        if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
1.35      mycroft   369:            in_nullhost(ip->ip_dst))
1.1       cgd       370:                goto ours;
                    371:
                    372:        /*
                    373:         * Not for us; forward if possible and desirable.
                    374:         */
                    375:        if (ipforwarding == 0) {
                    376:                ipstat.ips_cantforward++;
                    377:                m_freem(m);
                    378:        } else
                    379:                ip_forward(m, 0);
                    380:        goto next;
                    381:
                    382: ours:
                    383:        /*
                    384:         * If offset or IP_MF are set, must reassemble.
                    385:         * Otherwise, nothing need be done.
                    386:         * (We could look in the reassembly queue to see
                    387:         * if the packet was previously fragmented,
                    388:         * but it's not worth the time; just let them time out.)
                    389:         */
1.37      perry     390:        if (ip->ip_off & ~(IP_DF|IP_RF)) {
1.1       cgd       391:                /*
                    392:                 * Look for queue of fragments
                    393:                 * of this datagram.
                    394:                 */
1.25      cgd       395:                for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1       cgd       396:                        if (ip->ip_id == fp->ipq_id &&
1.35      mycroft   397:                            in_hosteq(ip->ip_src, fp->ipq_src) &&
                    398:                            in_hosteq(ip->ip_dst, fp->ipq_dst) &&
1.1       cgd       399:                            ip->ip_p == fp->ipq_p)
                    400:                                goto found;
                    401:                fp = 0;
                    402: found:
                    403:
                    404:                /*
                    405:                 * Adjust ip_len to not reflect header,
1.25      cgd       406:                 * set ipqe_mff if more fragments are expected,
1.1       cgd       407:                 * convert offset of this to bytes.
                    408:                 */
                    409:                ip->ip_len -= hlen;
1.25      cgd       410:                mff = (ip->ip_off & IP_MF) != 0;
                    411:                if (mff) {
1.16      cgd       412:                        /*
                    413:                         * Make sure that fragments have a data length
                    414:                         * that's a non-zero multiple of 8 bytes.
                    415:                         */
1.17      cgd       416:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16      cgd       417:                                ipstat.ips_badfrags++;
                    418:                                goto bad;
                    419:                        }
                    420:                }
1.1       cgd       421:                ip->ip_off <<= 3;
                    422:
                    423:                /*
                    424:                 * If datagram marked as having more fragments
                    425:                 * or if this is not the first fragment,
                    426:                 * attempt reassembly; if it succeeds, proceed.
                    427:                 */
1.25      cgd       428:                if (mff || ip->ip_off) {
1.1       cgd       429:                        ipstat.ips_fragments++;
1.25      cgd       430:                        MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent),
                    431:                            M_IPQ, M_NOWAIT);
                    432:                        if (ipqe == NULL) {
                    433:                                ipstat.ips_rcvmemdrop++;
                    434:                                goto bad;
                    435:                        }
                    436:                        ipqe->ipqe_mff = mff;
1.50      thorpej   437:                        ipqe->ipqe_m = m;
1.25      cgd       438:                        ipqe->ipqe_ip = ip;
1.50      thorpej   439:                        m = ip_reass(ipqe, fp);
                    440:                        if (m == 0)
1.1       cgd       441:                                goto next;
1.13      mycroft   442:                        ipstat.ips_reassembled++;
1.50      thorpej   443:                        ip = mtod(m, struct ip *);
1.1       cgd       444:                } else
                    445:                        if (fp)
                    446:                                ip_freef(fp);
                    447:        } else
                    448:                ip->ip_len -= hlen;
                    449:
                    450:        /*
                    451:         * Switch out to protocol's input routine.
                    452:         */
                    453:        ipstat.ips_delivered++;
                    454:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    455:        goto next;
                    456: bad:
                    457:        m_freem(m);
                    458:        goto next;
                    459: }
                    460:
                    461: /*
                    462:  * Take incoming datagram fragment and try to
                    463:  * reassemble it into whole datagram.  If a chain for
                    464:  * reassembly of this datagram already exists, then it
                    465:  * is given as fp; otherwise have to make a chain.
                    466:  */
1.50      thorpej   467: struct mbuf *
1.25      cgd       468: ip_reass(ipqe, fp)
                    469:        register struct ipqent *ipqe;
1.1       cgd       470:        register struct ipq *fp;
                    471: {
1.50      thorpej   472:        register struct mbuf *m = ipqe->ipqe_m;
1.25      cgd       473:        register struct ipqent *nq, *p, *q;
                    474:        struct ip *ip;
1.1       cgd       475:        struct mbuf *t;
1.25      cgd       476:        int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1       cgd       477:        int i, next;
                    478:
                    479:        /*
                    480:         * Presence of header sizes in mbufs
                    481:         * would confuse code below.
                    482:         */
                    483:        m->m_data += hlen;
                    484:        m->m_len -= hlen;
                    485:
                    486:        /*
                    487:         * If first fragment to arrive, create a reassembly queue.
                    488:         */
                    489:        if (fp == 0) {
1.50      thorpej   490:                MALLOC(fp, struct ipq *, sizeof (struct ipq),
                    491:                    M_FTABLE, M_NOWAIT);
                    492:                if (fp == NULL)
1.1       cgd       493:                        goto dropfrag;
1.25      cgd       494:                LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1       cgd       495:                fp->ipq_ttl = IPFRAGTTL;
1.25      cgd       496:                fp->ipq_p = ipqe->ipqe_ip->ip_p;
                    497:                fp->ipq_id = ipqe->ipqe_ip->ip_id;
                    498:                LIST_INIT(&fp->ipq_fragq);
                    499:                fp->ipq_src = ipqe->ipqe_ip->ip_src;
                    500:                fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
                    501:                p = NULL;
1.1       cgd       502:                goto insert;
                    503:        }
                    504:
                    505:        /*
                    506:         * Find a segment which begins after this one does.
                    507:         */
1.25      cgd       508:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    509:            p = q, q = q->ipqe_q.le_next)
                    510:                if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1       cgd       511:                        break;
                    512:
                    513:        /*
                    514:         * If there is a preceding segment, it may provide some of
                    515:         * our data already.  If so, drop the data from the incoming
                    516:         * segment.  If it provides all of our data, drop us.
                    517:         */
1.25      cgd       518:        if (p != NULL) {
                    519:                i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
                    520:                    ipqe->ipqe_ip->ip_off;
1.1       cgd       521:                if (i > 0) {
1.25      cgd       522:                        if (i >= ipqe->ipqe_ip->ip_len)
1.1       cgd       523:                                goto dropfrag;
1.50      thorpej   524:                        m_adj(ipqe->ipqe_m, i);
1.25      cgd       525:                        ipqe->ipqe_ip->ip_off += i;
                    526:                        ipqe->ipqe_ip->ip_len -= i;
1.1       cgd       527:                }
                    528:        }
                    529:
                    530:        /*
                    531:         * While we overlap succeeding segments trim them or,
                    532:         * if they are completely covered, dequeue them.
                    533:         */
1.25      cgd       534:        for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
                    535:            q->ipqe_ip->ip_off; q = nq) {
                    536:                i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
                    537:                    q->ipqe_ip->ip_off;
                    538:                if (i < q->ipqe_ip->ip_len) {
                    539:                        q->ipqe_ip->ip_len -= i;
                    540:                        q->ipqe_ip->ip_off += i;
1.50      thorpej   541:                        m_adj(q->ipqe_m, i);
1.1       cgd       542:                        break;
                    543:                }
1.25      cgd       544:                nq = q->ipqe_q.le_next;
1.50      thorpej   545:                m_freem(q->ipqe_m);
1.25      cgd       546:                LIST_REMOVE(q, ipqe_q);
                    547:                FREE(q, M_IPQ);
1.1       cgd       548:        }
                    549:
                    550: insert:
                    551:        /*
                    552:         * Stick new segment in its place;
                    553:         * check for complete reassembly.
                    554:         */
1.25      cgd       555:        if (p == NULL) {
                    556:                LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
                    557:        } else {
                    558:                LIST_INSERT_AFTER(p, ipqe, ipqe_q);
                    559:        }
1.1       cgd       560:        next = 0;
1.25      cgd       561:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    562:            p = q, q = q->ipqe_q.le_next) {
                    563:                if (q->ipqe_ip->ip_off != next)
1.1       cgd       564:                        return (0);
1.25      cgd       565:                next += q->ipqe_ip->ip_len;
1.1       cgd       566:        }
1.25      cgd       567:        if (p->ipqe_mff)
1.1       cgd       568:                return (0);
                    569:
                    570:        /*
1.41      thorpej   571:         * Reassembly is complete.  Check for a bogus message size and
                    572:         * concatenate fragments.
1.1       cgd       573:         */
1.25      cgd       574:        q = fp->ipq_fragq.lh_first;
                    575:        ip = q->ipqe_ip;
1.41      thorpej   576:        if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) {
                    577:                ipstat.ips_toolong++;
                    578:                ip_freef(fp);
                    579:                return (0);
                    580:        }
1.50      thorpej   581:        m = q->ipqe_m;
1.1       cgd       582:        t = m->m_next;
                    583:        m->m_next = 0;
                    584:        m_cat(m, t);
1.25      cgd       585:        nq = q->ipqe_q.le_next;
                    586:        FREE(q, M_IPQ);
                    587:        for (q = nq; q != NULL; q = nq) {
1.50      thorpej   588:                t = q->ipqe_m;
1.25      cgd       589:                nq = q->ipqe_q.le_next;
                    590:                FREE(q, M_IPQ);
1.1       cgd       591:                m_cat(m, t);
                    592:        }
                    593:
                    594:        /*
                    595:         * Create header for new ip packet by
                    596:         * modifying header of first packet;
                    597:         * dequeue and discard fragment reassembly header.
                    598:         * Make header visible.
                    599:         */
                    600:        ip->ip_len = next;
1.25      cgd       601:        ip->ip_src = fp->ipq_src;
                    602:        ip->ip_dst = fp->ipq_dst;
                    603:        LIST_REMOVE(fp, ipq_q);
1.50      thorpej   604:        FREE(fp, M_FTABLE);
1.1       cgd       605:        m->m_len += (ip->ip_hl << 2);
                    606:        m->m_data -= (ip->ip_hl << 2);
                    607:        /* some debugging cruft by sklower, below, will go away soon */
                    608:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
                    609:                register int plen = 0;
1.50      thorpej   610:                for (t = m; t; t = t->m_next)
                    611:                        plen += t->m_len;
                    612:                m->m_pkthdr.len = plen;
1.1       cgd       613:        }
1.50      thorpej   614:        return (m);
1.1       cgd       615:
                    616: dropfrag:
                    617:        ipstat.ips_fragdropped++;
                    618:        m_freem(m);
1.25      cgd       619:        FREE(ipqe, M_IPQ);
1.1       cgd       620:        return (0);
                    621: }
                    622:
                    623: /*
                    624:  * Free a fragment reassembly header and all
                    625:  * associated datagrams.
                    626:  */
1.8       mycroft   627: void
1.1       cgd       628: ip_freef(fp)
                    629:        struct ipq *fp;
                    630: {
1.25      cgd       631:        register struct ipqent *q, *p;
1.1       cgd       632:
1.25      cgd       633:        for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
                    634:                p = q->ipqe_q.le_next;
1.50      thorpej   635:                m_freem(q->ipqe_m);
1.25      cgd       636:                LIST_REMOVE(q, ipqe_q);
                    637:                FREE(q, M_IPQ);
1.1       cgd       638:        }
1.25      cgd       639:        LIST_REMOVE(fp, ipq_q);
1.50      thorpej   640:        FREE(fp, M_FTABLE);
1.1       cgd       641: }
                    642:
                    643: /*
                    644:  * IP timer processing;
                    645:  * if a timer expires on a reassembly
                    646:  * queue, discard it.
                    647:  */
1.8       mycroft   648: void
1.1       cgd       649: ip_slowtimo()
                    650: {
1.25      cgd       651:        register struct ipq *fp, *nfp;
1.24      mycroft   652:        int s = splsoftnet();
1.1       cgd       653:
1.25      cgd       654:        for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
                    655:                nfp = fp->ipq_q.le_next;
                    656:                if (--fp->ipq_ttl == 0) {
1.1       cgd       657:                        ipstat.ips_fragtimeout++;
1.25      cgd       658:                        ip_freef(fp);
1.1       cgd       659:                }
                    660:        }
                    661:        splx(s);
                    662: }
                    663:
                    664: /*
                    665:  * Drain off all datagram fragments.
                    666:  */
1.8       mycroft   667: void
1.1       cgd       668: ip_drain()
                    669: {
                    670:
1.25      cgd       671:        while (ipq.lh_first != NULL) {
1.1       cgd       672:                ipstat.ips_fragdropped++;
1.25      cgd       673:                ip_freef(ipq.lh_first);
1.1       cgd       674:        }
                    675: }
                    676:
                    677: /*
                    678:  * Do option processing on a datagram,
                    679:  * possibly discarding it if bad options are encountered,
                    680:  * or forwarding it if source-routed.
                    681:  * Returns 1 if packet has been forwarded/freed,
                    682:  * 0 if the packet should be processed further.
                    683:  */
1.8       mycroft   684: int
1.1       cgd       685: ip_dooptions(m)
                    686:        struct mbuf *m;
                    687: {
                    688:        register struct ip *ip = mtod(m, struct ip *);
                    689:        register u_char *cp;
                    690:        register struct ip_timestamp *ipt;
                    691:        register struct in_ifaddr *ia;
                    692:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13      mycroft   693:        struct in_addr *sin, dst;
1.1       cgd       694:        n_time ntime;
                    695:
1.13      mycroft   696:        dst = ip->ip_dst;
1.1       cgd       697:        cp = (u_char *)(ip + 1);
                    698:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    699:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    700:                opt = cp[IPOPT_OPTVAL];
                    701:                if (opt == IPOPT_EOL)
                    702:                        break;
                    703:                if (opt == IPOPT_NOP)
                    704:                        optlen = 1;
                    705:                else {
                    706:                        optlen = cp[IPOPT_OLEN];
                    707:                        if (optlen <= 0 || optlen > cnt) {
                    708:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    709:                                goto bad;
                    710:                        }
                    711:                }
                    712:                switch (opt) {
                    713:
                    714:                default:
                    715:                        break;
                    716:
                    717:                /*
                    718:                 * Source routing with record.
                    719:                 * Find interface with current destination address.
                    720:                 * If none on this machine then drop if strictly routed,
                    721:                 * or do nothing if loosely routed.
                    722:                 * Record interface address and bring up next address
                    723:                 * component.  If strictly routed make sure next
                    724:                 * address is on directly accessible net.
                    725:                 */
                    726:                case IPOPT_LSRR:
                    727:                case IPOPT_SSRR:
1.47      cjs       728:                        if (ip_allowsrcrt == 0) {
                    729:                                type = ICMP_UNREACH;
                    730:                                code = ICMP_UNREACH_NET_PROHIB;
                    731:                                goto bad;
                    732:                        }
1.1       cgd       733:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    734:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    735:                                goto bad;
                    736:                        }
                    737:                        ipaddr.sin_addr = ip->ip_dst;
1.19      mycroft   738:                        ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1       cgd       739:                        if (ia == 0) {
                    740:                                if (opt == IPOPT_SSRR) {
                    741:                                        type = ICMP_UNREACH;
                    742:                                        code = ICMP_UNREACH_SRCFAIL;
                    743:                                        goto bad;
                    744:                                }
                    745:                                /*
                    746:                                 * Loose routing, and not at next destination
                    747:                                 * yet; nothing to do except forward.
                    748:                                 */
                    749:                                break;
                    750:                        }
                    751:                        off--;                  /* 0 origin */
                    752:                        if (off > optlen - sizeof(struct in_addr)) {
                    753:                                /*
                    754:                                 * End of source route.  Should be for us.
                    755:                                 */
                    756:                                save_rte(cp, ip->ip_src);
                    757:                                break;
                    758:                        }
                    759:                        /*
                    760:                         * locate outgoing interface
                    761:                         */
                    762:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    763:                            sizeof(ipaddr.sin_addr));
                    764:                        if (opt == IPOPT_SSRR) {
                    765: #define        INA     struct in_ifaddr *
                    766: #define        SA      struct sockaddr *
1.29      mrg       767:                            ia = (INA)ifa_ifwithladdr((SA)&ipaddr);
1.1       cgd       768:                        } else
                    769:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    770:                        if (ia == 0) {
                    771:                                type = ICMP_UNREACH;
                    772:                                code = ICMP_UNREACH_SRCFAIL;
                    773:                                goto bad;
                    774:                        }
                    775:                        ip->ip_dst = ipaddr.sin_addr;
1.20      mycroft   776:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       777:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    778:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft   779:                        /*
                    780:                         * Let ip_intr's mcast routing check handle mcast pkts
                    781:                         */
1.18      mycroft   782:                        forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1       cgd       783:                        break;
                    784:
                    785:                case IPOPT_RR:
                    786:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    787:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    788:                                goto bad;
                    789:                        }
                    790:                        /*
                    791:                         * If no space remains, ignore.
                    792:                         */
                    793:                        off--;                  /* 0 origin */
                    794:                        if (off > optlen - sizeof(struct in_addr))
                    795:                                break;
                    796:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    797:                            sizeof(ipaddr.sin_addr));
                    798:                        /*
                    799:                         * locate outgoing interface; if we're the destination,
                    800:                         * use the incoming interface (should be same).
                    801:                         */
                    802:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    803:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    804:                                type = ICMP_UNREACH;
                    805:                                code = ICMP_UNREACH_HOST;
                    806:                                goto bad;
                    807:                        }
1.20      mycroft   808:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       809:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    810:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    811:                        break;
                    812:
                    813:                case IPOPT_TS:
                    814:                        code = cp - (u_char *)ip;
                    815:                        ipt = (struct ip_timestamp *)cp;
                    816:                        if (ipt->ipt_len < 5)
                    817:                                goto bad;
1.15      cgd       818:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1       cgd       819:                                if (++ipt->ipt_oflw == 0)
                    820:                                        goto bad;
                    821:                                break;
                    822:                        }
                    823:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    824:                        switch (ipt->ipt_flg) {
                    825:
                    826:                        case IPOPT_TS_TSONLY:
                    827:                                break;
                    828:
                    829:                        case IPOPT_TS_TSANDADDR:
                    830:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    831:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    832:                                        goto bad;
1.13      mycroft   833:                                ipaddr.sin_addr = dst;
                    834:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
                    835:                                                            m->m_pkthdr.rcvif);
                    836:                                if (ia == 0)
                    837:                                        continue;
1.20      mycroft   838:                                bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       839:                                    (caddr_t)sin, sizeof(struct in_addr));
                    840:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    841:                                break;
                    842:
                    843:                        case IPOPT_TS_PRESPEC:
                    844:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    845:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    846:                                        goto bad;
                    847:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    848:                                    sizeof(struct in_addr));
                    849:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    850:                                        continue;
                    851:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    852:                                break;
                    853:
                    854:                        default:
                    855:                                goto bad;
                    856:                        }
                    857:                        ntime = iptime();
                    858:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    859:                            sizeof(n_time));
                    860:                        ipt->ipt_ptr += sizeof(n_time);
                    861:                }
                    862:        }
                    863:        if (forward) {
1.26      thorpej   864:                if (ip_forwsrcrt == 0) {
                    865:                        type = ICMP_UNREACH;
                    866:                        code = ICMP_UNREACH_SRCFAIL;
                    867:                        goto bad;
                    868:                }
1.1       cgd       869:                ip_forward(m, 1);
                    870:                return (1);
1.13      mycroft   871:        }
                    872:        return (0);
1.1       cgd       873: bad:
1.13      mycroft   874:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
                    875:        icmp_error(m, type, code, 0, 0);
                    876:        ipstat.ips_badoptions++;
1.1       cgd       877:        return (1);
                    878: }
                    879:
                    880: /*
                    881:  * Given address of next destination (final or next hop),
                    882:  * return internet address info of interface to be used to get there.
                    883:  */
                    884: struct in_ifaddr *
                    885: ip_rtaddr(dst)
                    886:         struct in_addr dst;
                    887: {
                    888:        register struct sockaddr_in *sin;
                    889:
1.19      mycroft   890:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd       891:
1.35      mycroft   892:        if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) {
1.1       cgd       893:                if (ipforward_rt.ro_rt) {
                    894:                        RTFREE(ipforward_rt.ro_rt);
                    895:                        ipforward_rt.ro_rt = 0;
                    896:                }
                    897:                sin->sin_family = AF_INET;
                    898:                sin->sin_len = sizeof(*sin);
                    899:                sin->sin_addr = dst;
                    900:
                    901:                rtalloc(&ipforward_rt);
                    902:        }
                    903:        if (ipforward_rt.ro_rt == 0)
                    904:                return ((struct in_ifaddr *)0);
1.19      mycroft   905:        return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1       cgd       906: }
                    907:
                    908: /*
                    909:  * Save incoming source route for use in replies,
                    910:  * to be picked up later by ip_srcroute if the receiver is interested.
                    911:  */
1.13      mycroft   912: void
1.1       cgd       913: save_rte(option, dst)
                    914:        u_char *option;
                    915:        struct in_addr dst;
                    916: {
                    917:        unsigned olen;
                    918:
                    919:        olen = option[IPOPT_OLEN];
                    920: #ifdef DIAGNOSTIC
                    921:        if (ipprintfs)
1.39      christos  922:                printf("save_rte: olen %d\n", olen);
1.1       cgd       923: #endif
                    924:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    925:                return;
                    926:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    927:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    928:        ip_srcrt.dst = dst;
                    929: }
                    930:
                    931: /*
                    932:  * Retrieve incoming source route for use in replies,
                    933:  * in the same form used by setsockopt.
                    934:  * The first hop is placed before the options, will be removed later.
                    935:  */
                    936: struct mbuf *
                    937: ip_srcroute()
                    938: {
                    939:        register struct in_addr *p, *q;
                    940:        register struct mbuf *m;
                    941:
                    942:        if (ip_nhops == 0)
                    943:                return ((struct mbuf *)0);
                    944:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    945:        if (m == 0)
                    946:                return ((struct mbuf *)0);
                    947:
1.13      mycroft   948: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       949:
                    950:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    951:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    952:            OPTSIZ;
                    953: #ifdef DIAGNOSTIC
                    954:        if (ipprintfs)
1.39      christos  955:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
1.1       cgd       956: #endif
                    957:
                    958:        /*
                    959:         * First save first hop for return route
                    960:         */
                    961:        p = &ip_srcrt.route[ip_nhops - 1];
                    962:        *(mtod(m, struct in_addr *)) = *p--;
                    963: #ifdef DIAGNOSTIC
                    964:        if (ipprintfs)
1.39      christos  965:                printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1.1       cgd       966: #endif
                    967:
                    968:        /*
                    969:         * Copy option fields and padding (nop) to mbuf.
                    970:         */
                    971:        ip_srcrt.nop = IPOPT_NOP;
                    972:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    973:        bcopy((caddr_t)&ip_srcrt.nop,
                    974:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    975:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    976:            sizeof(struct in_addr) + OPTSIZ);
                    977: #undef OPTSIZ
                    978:        /*
                    979:         * Record return path as an IP source route,
                    980:         * reversing the path (pointers are now aligned).
                    981:         */
                    982:        while (p >= ip_srcrt.route) {
                    983: #ifdef DIAGNOSTIC
                    984:                if (ipprintfs)
1.39      christos  985:                        printf(" %x", ntohl(q->s_addr));
1.1       cgd       986: #endif
                    987:                *q++ = *p--;
                    988:        }
                    989:        /*
                    990:         * Last hop goes to final destination.
                    991:         */
                    992:        *q = ip_srcrt.dst;
                    993: #ifdef DIAGNOSTIC
                    994:        if (ipprintfs)
1.39      christos  995:                printf(" %x\n", ntohl(q->s_addr));
1.1       cgd       996: #endif
                    997:        return (m);
                    998: }
                    999:
                   1000: /*
                   1001:  * Strip out IP options, at higher
                   1002:  * level protocol in the kernel.
                   1003:  * Second argument is buffer to which options
                   1004:  * will be moved, and return value is their length.
                   1005:  * XXX should be deleted; last arg currently ignored.
                   1006:  */
1.8       mycroft  1007: void
1.1       cgd      1008: ip_stripoptions(m, mopt)
                   1009:        register struct mbuf *m;
                   1010:        struct mbuf *mopt;
                   1011: {
                   1012:        register int i;
                   1013:        struct ip *ip = mtod(m, struct ip *);
                   1014:        register caddr_t opts;
                   1015:        int olen;
                   1016:
                   1017:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                   1018:        opts = (caddr_t)(ip + 1);
                   1019:        i = m->m_len - (sizeof (struct ip) + olen);
                   1020:        bcopy(opts  + olen, opts, (unsigned)i);
                   1021:        m->m_len -= olen;
                   1022:        if (m->m_flags & M_PKTHDR)
                   1023:                m->m_pkthdr.len -= olen;
                   1024:        ip->ip_hl = sizeof(struct ip) >> 2;
                   1025: }
                   1026:
1.23      mycroft  1027: int inetctlerrmap[PRC_NCMDS] = {
1.1       cgd      1028:        0,              0,              0,              0,
                   1029:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                   1030:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                   1031:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                   1032:        0,              0,              0,              0,
                   1033:        ENOPROTOOPT
                   1034: };
                   1035:
                   1036: /*
                   1037:  * Forward a packet.  If some error occurs return the sender
                   1038:  * an icmp packet.  Note we can't always generate a meaningful
                   1039:  * icmp message because icmp doesn't have a large enough repertoire
                   1040:  * of codes and types.
                   1041:  *
                   1042:  * If not forwarding, just drop the packet.  This could be confusing
                   1043:  * if ipforwarding was zero but some routing protocol was advancing
                   1044:  * us as a gateway to somewhere.  However, we must let the routing
                   1045:  * protocol deal with that.
                   1046:  *
                   1047:  * The srcrt parameter indicates whether the packet is being forwarded
                   1048:  * via a source route.
                   1049:  */
1.13      mycroft  1050: void
1.1       cgd      1051: ip_forward(m, srcrt)
                   1052:        struct mbuf *m;
                   1053:        int srcrt;
                   1054: {
                   1055:        register struct ip *ip = mtod(m, struct ip *);
                   1056:        register struct sockaddr_in *sin;
                   1057:        register struct rtentry *rt;
1.28      christos 1058:        int error, type = 0, code = 0;
1.1       cgd      1059:        struct mbuf *mcopy;
1.13      mycroft  1060:        n_long dest;
                   1061:        struct ifnet *destifp;
1.1       cgd      1062:
1.13      mycroft  1063:        dest = 0;
1.1       cgd      1064: #ifdef DIAGNOSTIC
                   1065:        if (ipprintfs)
1.39      christos 1066:                printf("forward: src %x dst %x ttl %x\n",
1.35      mycroft  1067:                    ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl);
1.1       cgd      1068: #endif
                   1069:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1070:                ipstat.ips_cantforward++;
                   1071:                m_freem(m);
                   1072:                return;
                   1073:        }
                   1074:        HTONS(ip->ip_id);
                   1075:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1076:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1077:                return;
                   1078:        }
                   1079:        ip->ip_ttl -= IPTTLDEC;
                   1080:
1.19      mycroft  1081:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1082:        if ((rt = ipforward_rt.ro_rt) == 0 ||
1.35      mycroft  1083:            !in_hosteq(ip->ip_dst, sin->sin_addr)) {
1.1       cgd      1084:                if (ipforward_rt.ro_rt) {
                   1085:                        RTFREE(ipforward_rt.ro_rt);
                   1086:                        ipforward_rt.ro_rt = 0;
                   1087:                }
                   1088:                sin->sin_family = AF_INET;
1.35      mycroft  1089:                sin->sin_len = sizeof(struct sockaddr_in);
1.1       cgd      1090:                sin->sin_addr = ip->ip_dst;
                   1091:
                   1092:                rtalloc(&ipforward_rt);
                   1093:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1094:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1095:                        return;
                   1096:                }
                   1097:                rt = ipforward_rt.ro_rt;
                   1098:        }
                   1099:
                   1100:        /*
1.34      mycroft  1101:         * Save at most 68 bytes of the packet in case
1.1       cgd      1102:         * we need to generate an ICMP message to the src.
                   1103:         */
1.34      mycroft  1104:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 68));
1.1       cgd      1105:
                   1106:        /*
                   1107:         * If forwarding packet using same interface that it came in on,
                   1108:         * perhaps should send a redirect to sender to shortcut a hop.
                   1109:         * Only send redirect if source is sending directly to us,
                   1110:         * and if packet was not source routed (or has any options).
                   1111:         * Also, don't send redirect if forwarding using a default route
                   1112:         * or a route modified by a redirect.
                   1113:         */
                   1114:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1115:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1.35      mycroft  1116:            !in_nullhost(satosin(rt_key(rt))->sin_addr) &&
1.1       cgd      1117:            ipsendredirects && !srcrt) {
1.19      mycroft  1118:                if (rt->rt_ifa &&
                   1119:                    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
                   1120:                    ifatoia(rt->rt_ifa)->ia_subnet) {
1.1       cgd      1121:                    if (rt->rt_flags & RTF_GATEWAY)
1.13      mycroft  1122:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1123:                    else
1.13      mycroft  1124:                        dest = ip->ip_dst.s_addr;
                   1125:                    /* Router requirements says to only send host redirects */
1.1       cgd      1126:                    type = ICMP_REDIRECT;
1.13      mycroft  1127:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1128: #ifdef DIAGNOSTIC
                   1129:                    if (ipprintfs)
1.39      christos 1130:                        printf("redirect (%d) to %x\n", code, (u_int32_t)dest);
1.1       cgd      1131: #endif
                   1132:                }
                   1133:        }
                   1134:
1.27      thorpej  1135:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
                   1136:            (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0);
1.1       cgd      1137:        if (error)
                   1138:                ipstat.ips_cantforward++;
                   1139:        else {
                   1140:                ipstat.ips_forward++;
                   1141:                if (type)
                   1142:                        ipstat.ips_redirectsent++;
                   1143:                else {
                   1144:                        if (mcopy)
                   1145:                                m_freem(mcopy);
                   1146:                        return;
                   1147:                }
                   1148:        }
                   1149:        if (mcopy == NULL)
                   1150:                return;
1.13      mycroft  1151:        destifp = NULL;
                   1152:
1.1       cgd      1153:        switch (error) {
                   1154:
                   1155:        case 0:                         /* forwarded, but need redirect */
                   1156:                /* type, code set above */
                   1157:                break;
                   1158:
                   1159:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1160:        case EHOSTUNREACH:
                   1161:        case ENETDOWN:
                   1162:        case EHOSTDOWN:
                   1163:        default:
                   1164:                type = ICMP_UNREACH;
                   1165:                code = ICMP_UNREACH_HOST;
                   1166:                break;
                   1167:
                   1168:        case EMSGSIZE:
                   1169:                type = ICMP_UNREACH;
                   1170:                code = ICMP_UNREACH_NEEDFRAG;
1.13      mycroft  1171:                if (ipforward_rt.ro_rt)
                   1172:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1173:                ipstat.ips_cantfrag++;
                   1174:                break;
                   1175:
                   1176:        case ENOBUFS:
                   1177:                type = ICMP_SOURCEQUENCH;
                   1178:                code = 0;
                   1179:                break;
                   1180:        }
1.13      mycroft  1181:        icmp_error(mcopy, type, code, dest, destifp);
1.44      thorpej  1182: }
                   1183:
                   1184: void
                   1185: ip_savecontrol(inp, mp, ip, m)
                   1186:        register struct inpcb *inp;
                   1187:        register struct mbuf **mp;
                   1188:        register struct ip *ip;
                   1189:        register struct mbuf *m;
                   1190: {
                   1191:
                   1192:        if (inp->inp_socket->so_options & SO_TIMESTAMP) {
                   1193:                struct timeval tv;
                   1194:
                   1195:                microtime(&tv);
                   1196:                *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
                   1197:                    SCM_TIMESTAMP, SOL_SOCKET);
                   1198:                if (*mp)
                   1199:                        mp = &(*mp)->m_next;
                   1200:        }
                   1201:        if (inp->inp_flags & INP_RECVDSTADDR) {
                   1202:                *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
                   1203:                    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
                   1204:                if (*mp)
                   1205:                        mp = &(*mp)->m_next;
                   1206:        }
                   1207: #ifdef notyet
                   1208:        /*
                   1209:         * XXX
                   1210:         * Moving these out of udp_input() made them even more broken
                   1211:         * than they already were.
                   1212:         *      - fenner@parc.xerox.com
                   1213:         */
                   1214:        /* options were tossed already */
                   1215:        if (inp->inp_flags & INP_RECVOPTS) {
                   1216:                *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
                   1217:                    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
                   1218:                if (*mp)
                   1219:                        mp = &(*mp)->m_next;
                   1220:        }
                   1221:        /* ip_srcroute doesn't do what we want here, need to fix */
                   1222:        if (inp->inp_flags & INP_RECVRETOPTS) {
                   1223:                *mp = sbcreatecontrol((caddr_t) ip_srcroute(),
                   1224:                    sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
                   1225:                if (*mp)
                   1226:                        mp = &(*mp)->m_next;
                   1227:        }
                   1228: #endif
                   1229:        if (inp->inp_flags & INP_RECVIF) {
                   1230:                struct sockaddr_dl sdl;
                   1231:
                   1232:                sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]);
                   1233:                sdl.sdl_family = AF_LINK;
                   1234:                sdl.sdl_index = m->m_pkthdr.rcvif ?
                   1235:                    m->m_pkthdr.rcvif->if_index : 0;
                   1236:                sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0;
                   1237:                *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len,
                   1238:                    IP_RECVIF, IPPROTO_IP);
                   1239:                if (*mp)
                   1240:                        mp = &(*mp)->m_next;
                   1241:        }
1.13      mycroft  1242: }
                   1243:
                   1244: int
                   1245: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1246:        int *name;
                   1247:        u_int namelen;
                   1248:        void *oldp;
                   1249:        size_t *oldlenp;
                   1250:        void *newp;
                   1251:        size_t newlen;
                   1252: {
1.52      thorpej  1253:        extern int subnetsarelocal;
                   1254:
1.54      lukem    1255:        int error, old;
                   1256:
1.13      mycroft  1257:        /* All sysctl names at this level are terminal. */
                   1258:        if (namelen != 1)
                   1259:                return (ENOTDIR);
                   1260:
                   1261:        switch (name[0]) {
                   1262:        case IPCTL_FORWARDING:
                   1263:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
                   1264:        case IPCTL_SENDREDIRECTS:
                   1265:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1266:                        &ipsendredirects));
                   1267:        case IPCTL_DEFTTL:
                   1268:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
                   1269: #ifdef notyet
                   1270:        case IPCTL_DEFMTU:
                   1271:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
                   1272: #endif
1.26      thorpej  1273:        case IPCTL_FORWSRCRT:
1.47      cjs      1274:                /* Don't allow this to change in a secure environment.  */
1.26      thorpej  1275:                if (securelevel > 0)
1.46      cjs      1276:                        return (sysctl_rdint(oldp, oldlenp, newp,
                   1277:                            ip_forwsrcrt));
                   1278:                else
                   1279:                        return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1280:                            &ip_forwsrcrt));
1.27      thorpej  1281:        case IPCTL_DIRECTEDBCAST:
                   1282:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1283:                    &ip_directedbcast));
1.47      cjs      1284:        case IPCTL_ALLOWSRCRT:
                   1285:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1286:                    &ip_allowsrcrt));
1.52      thorpej  1287:        case IPCTL_SUBNETSARELOCAL:
                   1288:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1289:                    &subnetsarelocal));
1.53      kml      1290:        case IPCTL_MTUDISC:
1.54      lukem    1291:                return (sysctl_int(oldp, oldlenp, newp, newlen,
1.53      kml      1292:                    &ip_mtudisc));
1.54      lukem    1293:        case IPCTL_ANONPORTMIN:
                   1294:                old = anonportmin;
                   1295:                error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmin);
                   1296:                if (anonportmin >= anonportmax || anonportmin > 65535
                   1297: #ifndef IPNOPRIVPORTS
                   1298:                    || anonportmin < IPPORT_RESERVED
                   1299: #endif
                   1300:                    ) {
                   1301:                        anonportmin = old;
                   1302:                        return (EINVAL);
                   1303:                }
                   1304:                return (error);
                   1305:        case IPCTL_ANONPORTMAX:
                   1306:                old = anonportmax;
                   1307:                error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmax);
                   1308:                if (anonportmin >= anonportmax || anonportmax > 65535
                   1309: #ifndef IPNOPRIVPORTS
                   1310:                    || anonportmax < IPPORT_RESERVED
                   1311: #endif
                   1312:                    ) {
                   1313:                        anonportmax = old;
                   1314:                        return (EINVAL);
                   1315:                }
                   1316:                return (error);
1.13      mycroft  1317:        default:
                   1318:                return (EOPNOTSUPP);
                   1319:        }
                   1320:        /* NOTREACHED */
1.1       cgd      1321: }

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