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Annotation of src/sys/netinet/ip_input.c, Revision 1.56

1.56    ! thorpej     1: /*     $NetBSD: ip_input.c,v 1.55 1998/01/12 03:02:51 scottr 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;
1.13      mycroft   116: struct ifqueue ipintrq;
1.1       cgd       117:
                    118: /*
                    119:  * We need to save the IP options in case a protocol wants to respond
                    120:  * to an incoming packet over the same route if the packet got here
                    121:  * using IP source routing.  This allows connection establishment and
                    122:  * maintenance when the remote end is on a network that is not known
                    123:  * to us.
                    124:  */
                    125: int    ip_nhops = 0;
                    126: static struct ip_srcrt {
                    127:        struct  in_addr dst;                    /* final destination */
                    128:        char    nop;                            /* one NOP to align */
                    129:        char    srcopt[IPOPT_OFFSET + 1];       /* OPTVAL, OLEN and OFFSET */
                    130:        struct  in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
                    131: } ip_srcrt;
                    132:
1.13      mycroft   133: static void save_rte __P((u_char *, struct in_addr));
1.35      mycroft   134:
1.1       cgd       135: /*
                    136:  * IP initialization: fill in IP protocol switch table.
                    137:  * All protocols not implemented in kernel go to raw IP protocol handler.
                    138:  */
1.8       mycroft   139: void
1.1       cgd       140: ip_init()
                    141: {
                    142:        register struct protosw *pr;
                    143:        register int i;
                    144:
                    145:        pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
                    146:        if (pr == 0)
                    147:                panic("ip_init");
                    148:        for (i = 0; i < IPPROTO_MAX; i++)
                    149:                ip_protox[i] = pr - inetsw;
                    150:        for (pr = inetdomain.dom_protosw;
                    151:            pr < inetdomain.dom_protoswNPROTOSW; pr++)
                    152:                if (pr->pr_domain->dom_family == PF_INET &&
                    153:                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
                    154:                        ip_protox[pr->pr_protocol] = pr - inetsw;
1.25      cgd       155:        LIST_INIT(&ipq);
1.1       cgd       156:        ip_id = time.tv_sec & 0xffff;
                    157:        ipintrq.ifq_maxlen = ipqmaxlen;
1.22      mycroft   158:        TAILQ_INIT(&in_ifaddr);
1.1       cgd       159: }
                    160:
                    161: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    162: struct route ipforward_rt;
                    163:
                    164: /*
                    165:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    166:  * try to reassemble.  Process options.  Pass to next level.
                    167:  */
1.8       mycroft   168: void
1.1       cgd       169: ipintr()
                    170: {
1.33      mrg       171:        register struct ip *ip = NULL;
1.1       cgd       172:        register struct mbuf *m;
                    173:        register struct ipq *fp;
                    174:        register struct in_ifaddr *ia;
1.25      cgd       175:        struct ipqent *ipqe;
1.35      mycroft   176:        int hlen = 0, mff, len, s;
1.36      mrg       177: #ifdef PFIL_HOOKS
1.33      mrg       178:        struct packet_filter_hook *pfh;
                    179:        struct mbuf *m0;
1.43      mrg       180:        int rv;
1.36      mrg       181: #endif /* PFIL_HOOKS */
1.1       cgd       182:
                    183: next:
                    184:        /*
                    185:         * Get next datagram off input queue and get IP header
                    186:         * in first mbuf.
                    187:         */
                    188:        s = splimp();
                    189:        IF_DEQUEUE(&ipintrq, m);
                    190:        splx(s);
1.13      mycroft   191:        if (m == 0)
1.1       cgd       192:                return;
                    193: #ifdef DIAGNOSTIC
                    194:        if ((m->m_flags & M_PKTHDR) == 0)
                    195:                panic("ipintr no HDR");
                    196: #endif
                    197:        /*
                    198:         * If no IP addresses have been set yet but the interfaces
                    199:         * are receiving, can't do anything with incoming packets yet.
                    200:         */
1.22      mycroft   201:        if (in_ifaddr.tqh_first == 0)
1.1       cgd       202:                goto bad;
                    203:        ipstat.ips_total++;
                    204:        if (m->m_len < sizeof (struct ip) &&
                    205:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    206:                ipstat.ips_toosmall++;
                    207:                goto next;
                    208:        }
                    209:        ip = mtod(m, struct ip *);
1.13      mycroft   210:        if (ip->ip_v != IPVERSION) {
                    211:                ipstat.ips_badvers++;
                    212:                goto bad;
                    213:        }
1.1       cgd       214:        hlen = ip->ip_hl << 2;
                    215:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    216:                ipstat.ips_badhlen++;
                    217:                goto bad;
                    218:        }
                    219:        if (hlen > m->m_len) {
                    220:                if ((m = m_pullup(m, hlen)) == 0) {
                    221:                        ipstat.ips_badhlen++;
                    222:                        goto next;
                    223:                }
                    224:                ip = mtod(m, struct ip *);
                    225:        }
1.28      christos  226:        if ((ip->ip_sum = in_cksum(m, hlen)) != 0) {
1.1       cgd       227:                ipstat.ips_badsum++;
                    228:                goto bad;
                    229:        }
                    230:
                    231:        /*
                    232:         * Convert fields to host representation.
                    233:         */
                    234:        NTOHS(ip->ip_len);
                    235:        NTOHS(ip->ip_id);
                    236:        NTOHS(ip->ip_off);
1.35      mycroft   237:        len = ip->ip_len;
1.1       cgd       238:
                    239:        /*
                    240:         * Check that the amount of data in the buffers
                    241:         * is as at least much as the IP header would have us expect.
                    242:         * Trim mbufs if longer than we expect.
                    243:         * Drop packet if shorter than we expect.
                    244:         */
1.35      mycroft   245:        if (m->m_pkthdr.len < len) {
1.1       cgd       246:                ipstat.ips_tooshort++;
                    247:                goto bad;
                    248:        }
1.35      mycroft   249:        if (m->m_pkthdr.len > len) {
1.1       cgd       250:                if (m->m_len == m->m_pkthdr.len) {
1.35      mycroft   251:                        m->m_len = len;
                    252:                        m->m_pkthdr.len = len;
1.1       cgd       253:                } else
1.35      mycroft   254:                        m_adj(m, len - m->m_pkthdr.len);
1.1       cgd       255:        }
                    256:
1.36      mrg       257: #ifdef PFIL_HOOKS
1.33      mrg       258:        /*
                    259:         * Run through list of hooks for input packets.
                    260:         */
                    261:        m0 = m;
                    262:        for (pfh = pfil_hook_get(PFIL_IN); pfh; pfh = pfh->pfil_link.le_next)
                    263:                if (pfh->pfil_func) {
1.43      mrg       264:                        rv = pfh->pfil_func(ip, hlen, m->m_pkthdr.rcvif, 0, &m0);
                    265:                        if (rv)
1.40      veego     266:                                goto next;
1.49      christos  267:                        ip = mtod(m = m0, struct ip *);
1.33      mrg       268:                }
1.36      mrg       269: #endif /* PFIL_HOOKS */
1.33      mrg       270:
1.1       cgd       271:        /*
                    272:         * Process options and, if not destined for us,
                    273:         * ship it on.  ip_dooptions returns 1 when an
                    274:         * error was detected (causing an icmp message
                    275:         * to be sent and the original packet to be freed).
                    276:         */
                    277:        ip_nhops = 0;           /* for source routed packets */
                    278:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    279:                goto next;
                    280:
                    281:        /*
                    282:         * Check our list of addresses, to see if the packet is for us.
                    283:         */
1.22      mycroft   284:        for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
1.35      mycroft   285:                if (in_hosteq(ip->ip_dst, ia->ia_addr.sin_addr))
1.1       cgd       286:                        goto ours;
1.27      thorpej   287:                if (((ip_directedbcast == 0) || (ip_directedbcast &&
                    288:                    ia->ia_ifp == m->m_pkthdr.rcvif)) &&
1.1       cgd       289:                    (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.35      mycroft   290:                        if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
                    291:                            in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
1.20      mycroft   292:                            /*
                    293:                             * Look for all-0's host part (old broadcast addr),
                    294:                             * either for subnet or net.
                    295:                             */
                    296:                            ip->ip_dst.s_addr == ia->ia_subnet ||
1.18      mycroft   297:                            ip->ip_dst.s_addr == ia->ia_net)
1.1       cgd       298:                                goto ours;
                    299:                }
1.51      gwr       300:                /*
                    301:                 * An interface with IP address zero accepts
                    302:                 * all packets that arrive on that interface.
                    303:                 */
                    304:                if ((ia->ia_ifp == m->m_pkthdr.rcvif) &&
                    305:                    in_nullhost(ia->ia_addr.sin_addr))
                    306:                        goto ours;
1.1       cgd       307:        }
1.18      mycroft   308:        if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4       hpeyerl   309:                struct in_multi *inm;
                    310: #ifdef MROUTING
                    311:                extern struct socket *ip_mrouter;
1.10      brezak    312:
                    313:                if (m->m_flags & M_EXT) {
                    314:                        if ((m = m_pullup(m, hlen)) == 0) {
                    315:                                ipstat.ips_toosmall++;
                    316:                                goto next;
                    317:                        }
                    318:                        ip = mtod(m, struct ip *);
                    319:                }
1.4       hpeyerl   320:
                    321:                if (ip_mrouter) {
                    322:                        /*
                    323:                         * If we are acting as a multicast router, all
                    324:                         * incoming multicast packets are passed to the
                    325:                         * kernel-level multicast forwarding function.
                    326:                         * The packet is returned (relatively) intact; if
                    327:                         * ip_mforward() returns a non-zero value, the packet
                    328:                         * must be discarded, else it may be accepted below.
                    329:                         *
                    330:                         * (The IP ident field is put in the same byte order
                    331:                         * as expected when ip_mforward() is called from
                    332:                         * ip_output().)
                    333:                         */
                    334:                        ip->ip_id = htons(ip->ip_id);
1.13      mycroft   335:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    336:                                ipstat.ips_cantforward++;
1.4       hpeyerl   337:                                m_freem(m);
                    338:                                goto next;
                    339:                        }
                    340:                        ip->ip_id = ntohs(ip->ip_id);
                    341:
                    342:                        /*
                    343:                         * The process-level routing demon needs to receive
                    344:                         * all multicast IGMP packets, whether or not this
                    345:                         * host belongs to their destination groups.
                    346:                         */
                    347:                        if (ip->ip_p == IPPROTO_IGMP)
                    348:                                goto ours;
1.13      mycroft   349:                        ipstat.ips_forward++;
1.4       hpeyerl   350:                }
                    351: #endif
                    352:                /*
                    353:                 * See if we belong to the destination multicast group on the
                    354:                 * arrival interface.
                    355:                 */
                    356:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    357:                if (inm == NULL) {
1.13      mycroft   358:                        ipstat.ips_cantforward++;
1.4       hpeyerl   359:                        m_freem(m);
                    360:                        goto next;
                    361:                }
                    362:                goto ours;
                    363:        }
1.19      mycroft   364:        if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
1.35      mycroft   365:            in_nullhost(ip->ip_dst))
1.1       cgd       366:                goto ours;
                    367:
                    368:        /*
                    369:         * Not for us; forward if possible and desirable.
                    370:         */
                    371:        if (ipforwarding == 0) {
                    372:                ipstat.ips_cantforward++;
                    373:                m_freem(m);
                    374:        } else
                    375:                ip_forward(m, 0);
                    376:        goto next;
                    377:
                    378: ours:
                    379:        /*
                    380:         * If offset or IP_MF are set, must reassemble.
                    381:         * Otherwise, nothing need be done.
                    382:         * (We could look in the reassembly queue to see
                    383:         * if the packet was previously fragmented,
                    384:         * but it's not worth the time; just let them time out.)
                    385:         */
1.37      perry     386:        if (ip->ip_off & ~(IP_DF|IP_RF)) {
1.1       cgd       387:                /*
                    388:                 * Look for queue of fragments
                    389:                 * of this datagram.
                    390:                 */
1.25      cgd       391:                for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1       cgd       392:                        if (ip->ip_id == fp->ipq_id &&
1.35      mycroft   393:                            in_hosteq(ip->ip_src, fp->ipq_src) &&
                    394:                            in_hosteq(ip->ip_dst, fp->ipq_dst) &&
1.1       cgd       395:                            ip->ip_p == fp->ipq_p)
                    396:                                goto found;
                    397:                fp = 0;
                    398: found:
                    399:
                    400:                /*
                    401:                 * Adjust ip_len to not reflect header,
1.25      cgd       402:                 * set ipqe_mff if more fragments are expected,
1.1       cgd       403:                 * convert offset of this to bytes.
                    404:                 */
                    405:                ip->ip_len -= hlen;
1.25      cgd       406:                mff = (ip->ip_off & IP_MF) != 0;
                    407:                if (mff) {
1.16      cgd       408:                        /*
                    409:                         * Make sure that fragments have a data length
                    410:                         * that's a non-zero multiple of 8 bytes.
                    411:                         */
1.17      cgd       412:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16      cgd       413:                                ipstat.ips_badfrags++;
                    414:                                goto bad;
                    415:                        }
                    416:                }
1.1       cgd       417:                ip->ip_off <<= 3;
                    418:
                    419:                /*
                    420:                 * If datagram marked as having more fragments
                    421:                 * or if this is not the first fragment,
                    422:                 * attempt reassembly; if it succeeds, proceed.
                    423:                 */
1.25      cgd       424:                if (mff || ip->ip_off) {
1.1       cgd       425:                        ipstat.ips_fragments++;
1.25      cgd       426:                        MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent),
                    427:                            M_IPQ, M_NOWAIT);
                    428:                        if (ipqe == NULL) {
                    429:                                ipstat.ips_rcvmemdrop++;
                    430:                                goto bad;
                    431:                        }
                    432:                        ipqe->ipqe_mff = mff;
1.50      thorpej   433:                        ipqe->ipqe_m = m;
1.25      cgd       434:                        ipqe->ipqe_ip = ip;
1.50      thorpej   435:                        m = ip_reass(ipqe, fp);
                    436:                        if (m == 0)
1.1       cgd       437:                                goto next;
1.13      mycroft   438:                        ipstat.ips_reassembled++;
1.50      thorpej   439:                        ip = mtod(m, struct ip *);
1.1       cgd       440:                } else
                    441:                        if (fp)
                    442:                                ip_freef(fp);
                    443:        } else
                    444:                ip->ip_len -= hlen;
                    445:
                    446:        /*
                    447:         * Switch out to protocol's input routine.
                    448:         */
                    449:        ipstat.ips_delivered++;
                    450:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    451:        goto next;
                    452: bad:
                    453:        m_freem(m);
                    454:        goto next;
                    455: }
                    456:
                    457: /*
                    458:  * Take incoming datagram fragment and try to
                    459:  * reassemble it into whole datagram.  If a chain for
                    460:  * reassembly of this datagram already exists, then it
                    461:  * is given as fp; otherwise have to make a chain.
                    462:  */
1.50      thorpej   463: struct mbuf *
1.25      cgd       464: ip_reass(ipqe, fp)
                    465:        register struct ipqent *ipqe;
1.1       cgd       466:        register struct ipq *fp;
                    467: {
1.50      thorpej   468:        register struct mbuf *m = ipqe->ipqe_m;
1.25      cgd       469:        register struct ipqent *nq, *p, *q;
                    470:        struct ip *ip;
1.1       cgd       471:        struct mbuf *t;
1.25      cgd       472:        int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1       cgd       473:        int i, next;
                    474:
                    475:        /*
                    476:         * Presence of header sizes in mbufs
                    477:         * would confuse code below.
                    478:         */
                    479:        m->m_data += hlen;
                    480:        m->m_len -= hlen;
                    481:
                    482:        /*
                    483:         * If first fragment to arrive, create a reassembly queue.
                    484:         */
                    485:        if (fp == 0) {
1.50      thorpej   486:                MALLOC(fp, struct ipq *, sizeof (struct ipq),
                    487:                    M_FTABLE, M_NOWAIT);
                    488:                if (fp == NULL)
1.1       cgd       489:                        goto dropfrag;
1.25      cgd       490:                LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1       cgd       491:                fp->ipq_ttl = IPFRAGTTL;
1.25      cgd       492:                fp->ipq_p = ipqe->ipqe_ip->ip_p;
                    493:                fp->ipq_id = ipqe->ipqe_ip->ip_id;
                    494:                LIST_INIT(&fp->ipq_fragq);
                    495:                fp->ipq_src = ipqe->ipqe_ip->ip_src;
                    496:                fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
                    497:                p = NULL;
1.1       cgd       498:                goto insert;
                    499:        }
                    500:
                    501:        /*
                    502:         * Find a segment which begins after this one does.
                    503:         */
1.25      cgd       504:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    505:            p = q, q = q->ipqe_q.le_next)
                    506:                if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1       cgd       507:                        break;
                    508:
                    509:        /*
                    510:         * If there is a preceding segment, it may provide some of
                    511:         * our data already.  If so, drop the data from the incoming
                    512:         * segment.  If it provides all of our data, drop us.
                    513:         */
1.25      cgd       514:        if (p != NULL) {
                    515:                i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
                    516:                    ipqe->ipqe_ip->ip_off;
1.1       cgd       517:                if (i > 0) {
1.25      cgd       518:                        if (i >= ipqe->ipqe_ip->ip_len)
1.1       cgd       519:                                goto dropfrag;
1.50      thorpej   520:                        m_adj(ipqe->ipqe_m, i);
1.25      cgd       521:                        ipqe->ipqe_ip->ip_off += i;
                    522:                        ipqe->ipqe_ip->ip_len -= i;
1.1       cgd       523:                }
                    524:        }
                    525:
                    526:        /*
                    527:         * While we overlap succeeding segments trim them or,
                    528:         * if they are completely covered, dequeue them.
                    529:         */
1.25      cgd       530:        for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
                    531:            q->ipqe_ip->ip_off; q = nq) {
                    532:                i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
                    533:                    q->ipqe_ip->ip_off;
                    534:                if (i < q->ipqe_ip->ip_len) {
                    535:                        q->ipqe_ip->ip_len -= i;
                    536:                        q->ipqe_ip->ip_off += i;
1.50      thorpej   537:                        m_adj(q->ipqe_m, i);
1.1       cgd       538:                        break;
                    539:                }
1.25      cgd       540:                nq = q->ipqe_q.le_next;
1.50      thorpej   541:                m_freem(q->ipqe_m);
1.25      cgd       542:                LIST_REMOVE(q, ipqe_q);
                    543:                FREE(q, M_IPQ);
1.1       cgd       544:        }
                    545:
                    546: insert:
                    547:        /*
                    548:         * Stick new segment in its place;
                    549:         * check for complete reassembly.
                    550:         */
1.25      cgd       551:        if (p == NULL) {
                    552:                LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
                    553:        } else {
                    554:                LIST_INSERT_AFTER(p, ipqe, ipqe_q);
                    555:        }
1.1       cgd       556:        next = 0;
1.25      cgd       557:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    558:            p = q, q = q->ipqe_q.le_next) {
                    559:                if (q->ipqe_ip->ip_off != next)
1.1       cgd       560:                        return (0);
1.25      cgd       561:                next += q->ipqe_ip->ip_len;
1.1       cgd       562:        }
1.25      cgd       563:        if (p->ipqe_mff)
1.1       cgd       564:                return (0);
                    565:
                    566:        /*
1.41      thorpej   567:         * Reassembly is complete.  Check for a bogus message size and
                    568:         * concatenate fragments.
1.1       cgd       569:         */
1.25      cgd       570:        q = fp->ipq_fragq.lh_first;
                    571:        ip = q->ipqe_ip;
1.41      thorpej   572:        if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) {
                    573:                ipstat.ips_toolong++;
                    574:                ip_freef(fp);
                    575:                return (0);
                    576:        }
1.50      thorpej   577:        m = q->ipqe_m;
1.1       cgd       578:        t = m->m_next;
                    579:        m->m_next = 0;
                    580:        m_cat(m, t);
1.25      cgd       581:        nq = q->ipqe_q.le_next;
                    582:        FREE(q, M_IPQ);
                    583:        for (q = nq; q != NULL; q = nq) {
1.50      thorpej   584:                t = q->ipqe_m;
1.25      cgd       585:                nq = q->ipqe_q.le_next;
                    586:                FREE(q, M_IPQ);
1.1       cgd       587:                m_cat(m, t);
                    588:        }
                    589:
                    590:        /*
                    591:         * Create header for new ip packet by
                    592:         * modifying header of first packet;
                    593:         * dequeue and discard fragment reassembly header.
                    594:         * Make header visible.
                    595:         */
                    596:        ip->ip_len = next;
1.25      cgd       597:        ip->ip_src = fp->ipq_src;
                    598:        ip->ip_dst = fp->ipq_dst;
                    599:        LIST_REMOVE(fp, ipq_q);
1.50      thorpej   600:        FREE(fp, M_FTABLE);
1.1       cgd       601:        m->m_len += (ip->ip_hl << 2);
                    602:        m->m_data -= (ip->ip_hl << 2);
                    603:        /* some debugging cruft by sklower, below, will go away soon */
                    604:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
                    605:                register int plen = 0;
1.50      thorpej   606:                for (t = m; t; t = t->m_next)
                    607:                        plen += t->m_len;
                    608:                m->m_pkthdr.len = plen;
1.1       cgd       609:        }
1.50      thorpej   610:        return (m);
1.1       cgd       611:
                    612: dropfrag:
                    613:        ipstat.ips_fragdropped++;
                    614:        m_freem(m);
1.25      cgd       615:        FREE(ipqe, M_IPQ);
1.1       cgd       616:        return (0);
                    617: }
                    618:
                    619: /*
                    620:  * Free a fragment reassembly header and all
                    621:  * associated datagrams.
                    622:  */
1.8       mycroft   623: void
1.1       cgd       624: ip_freef(fp)
                    625:        struct ipq *fp;
                    626: {
1.25      cgd       627:        register struct ipqent *q, *p;
1.1       cgd       628:
1.25      cgd       629:        for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
                    630:                p = q->ipqe_q.le_next;
1.50      thorpej   631:                m_freem(q->ipqe_m);
1.25      cgd       632:                LIST_REMOVE(q, ipqe_q);
                    633:                FREE(q, M_IPQ);
1.1       cgd       634:        }
1.25      cgd       635:        LIST_REMOVE(fp, ipq_q);
1.50      thorpej   636:        FREE(fp, M_FTABLE);
1.1       cgd       637: }
                    638:
                    639: /*
                    640:  * IP timer processing;
                    641:  * if a timer expires on a reassembly
                    642:  * queue, discard it.
                    643:  */
1.8       mycroft   644: void
1.1       cgd       645: ip_slowtimo()
                    646: {
1.25      cgd       647:        register struct ipq *fp, *nfp;
1.24      mycroft   648:        int s = splsoftnet();
1.1       cgd       649:
1.25      cgd       650:        for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
                    651:                nfp = fp->ipq_q.le_next;
                    652:                if (--fp->ipq_ttl == 0) {
1.1       cgd       653:                        ipstat.ips_fragtimeout++;
1.25      cgd       654:                        ip_freef(fp);
1.1       cgd       655:                }
                    656:        }
                    657:        splx(s);
                    658: }
                    659:
                    660: /*
                    661:  * Drain off all datagram fragments.
                    662:  */
1.8       mycroft   663: void
1.1       cgd       664: ip_drain()
                    665: {
                    666:
1.25      cgd       667:        while (ipq.lh_first != NULL) {
1.1       cgd       668:                ipstat.ips_fragdropped++;
1.25      cgd       669:                ip_freef(ipq.lh_first);
1.1       cgd       670:        }
                    671: }
                    672:
                    673: /*
                    674:  * Do option processing on a datagram,
                    675:  * possibly discarding it if bad options are encountered,
                    676:  * or forwarding it if source-routed.
                    677:  * Returns 1 if packet has been forwarded/freed,
                    678:  * 0 if the packet should be processed further.
                    679:  */
1.8       mycroft   680: int
1.1       cgd       681: ip_dooptions(m)
                    682:        struct mbuf *m;
                    683: {
                    684:        register struct ip *ip = mtod(m, struct ip *);
                    685:        register u_char *cp;
                    686:        register struct ip_timestamp *ipt;
                    687:        register struct in_ifaddr *ia;
                    688:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13      mycroft   689:        struct in_addr *sin, dst;
1.1       cgd       690:        n_time ntime;
                    691:
1.13      mycroft   692:        dst = ip->ip_dst;
1.1       cgd       693:        cp = (u_char *)(ip + 1);
                    694:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    695:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    696:                opt = cp[IPOPT_OPTVAL];
                    697:                if (opt == IPOPT_EOL)
                    698:                        break;
                    699:                if (opt == IPOPT_NOP)
                    700:                        optlen = 1;
                    701:                else {
                    702:                        optlen = cp[IPOPT_OLEN];
                    703:                        if (optlen <= 0 || optlen > cnt) {
                    704:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    705:                                goto bad;
                    706:                        }
                    707:                }
                    708:                switch (opt) {
                    709:
                    710:                default:
                    711:                        break;
                    712:
                    713:                /*
                    714:                 * Source routing with record.
                    715:                 * Find interface with current destination address.
                    716:                 * If none on this machine then drop if strictly routed,
                    717:                 * or do nothing if loosely routed.
                    718:                 * Record interface address and bring up next address
                    719:                 * component.  If strictly routed make sure next
                    720:                 * address is on directly accessible net.
                    721:                 */
                    722:                case IPOPT_LSRR:
                    723:                case IPOPT_SSRR:
1.47      cjs       724:                        if (ip_allowsrcrt == 0) {
                    725:                                type = ICMP_UNREACH;
                    726:                                code = ICMP_UNREACH_NET_PROHIB;
                    727:                                goto bad;
                    728:                        }
1.1       cgd       729:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    730:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    731:                                goto bad;
                    732:                        }
                    733:                        ipaddr.sin_addr = ip->ip_dst;
1.19      mycroft   734:                        ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1       cgd       735:                        if (ia == 0) {
                    736:                                if (opt == IPOPT_SSRR) {
                    737:                                        type = ICMP_UNREACH;
                    738:                                        code = ICMP_UNREACH_SRCFAIL;
                    739:                                        goto bad;
                    740:                                }
                    741:                                /*
                    742:                                 * Loose routing, and not at next destination
                    743:                                 * yet; nothing to do except forward.
                    744:                                 */
                    745:                                break;
                    746:                        }
                    747:                        off--;                  /* 0 origin */
                    748:                        if (off > optlen - sizeof(struct in_addr)) {
                    749:                                /*
                    750:                                 * End of source route.  Should be for us.
                    751:                                 */
                    752:                                save_rte(cp, ip->ip_src);
                    753:                                break;
                    754:                        }
                    755:                        /*
                    756:                         * locate outgoing interface
                    757:                         */
                    758:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    759:                            sizeof(ipaddr.sin_addr));
                    760:                        if (opt == IPOPT_SSRR) {
                    761: #define        INA     struct in_ifaddr *
                    762: #define        SA      struct sockaddr *
1.29      mrg       763:                            ia = (INA)ifa_ifwithladdr((SA)&ipaddr);
1.1       cgd       764:                        } else
                    765:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    766:                        if (ia == 0) {
                    767:                                type = ICMP_UNREACH;
                    768:                                code = ICMP_UNREACH_SRCFAIL;
                    769:                                goto bad;
                    770:                        }
                    771:                        ip->ip_dst = ipaddr.sin_addr;
1.20      mycroft   772:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       773:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    774:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft   775:                        /*
                    776:                         * Let ip_intr's mcast routing check handle mcast pkts
                    777:                         */
1.18      mycroft   778:                        forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1       cgd       779:                        break;
                    780:
                    781:                case IPOPT_RR:
                    782:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    783:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    784:                                goto bad;
                    785:                        }
                    786:                        /*
                    787:                         * If no space remains, ignore.
                    788:                         */
                    789:                        off--;                  /* 0 origin */
                    790:                        if (off > optlen - sizeof(struct in_addr))
                    791:                                break;
                    792:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    793:                            sizeof(ipaddr.sin_addr));
                    794:                        /*
                    795:                         * locate outgoing interface; if we're the destination,
                    796:                         * use the incoming interface (should be same).
                    797:                         */
                    798:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    799:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    800:                                type = ICMP_UNREACH;
                    801:                                code = ICMP_UNREACH_HOST;
                    802:                                goto bad;
                    803:                        }
1.20      mycroft   804:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       805:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    806:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    807:                        break;
                    808:
                    809:                case IPOPT_TS:
                    810:                        code = cp - (u_char *)ip;
                    811:                        ipt = (struct ip_timestamp *)cp;
                    812:                        if (ipt->ipt_len < 5)
                    813:                                goto bad;
1.15      cgd       814:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1       cgd       815:                                if (++ipt->ipt_oflw == 0)
                    816:                                        goto bad;
                    817:                                break;
                    818:                        }
                    819:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    820:                        switch (ipt->ipt_flg) {
                    821:
                    822:                        case IPOPT_TS_TSONLY:
                    823:                                break;
                    824:
                    825:                        case IPOPT_TS_TSANDADDR:
                    826:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    827:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    828:                                        goto bad;
1.13      mycroft   829:                                ipaddr.sin_addr = dst;
                    830:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
                    831:                                                            m->m_pkthdr.rcvif);
                    832:                                if (ia == 0)
                    833:                                        continue;
1.20      mycroft   834:                                bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       835:                                    (caddr_t)sin, sizeof(struct in_addr));
                    836:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    837:                                break;
                    838:
                    839:                        case IPOPT_TS_PRESPEC:
                    840:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    841:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    842:                                        goto bad;
                    843:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    844:                                    sizeof(struct in_addr));
                    845:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    846:                                        continue;
                    847:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    848:                                break;
                    849:
                    850:                        default:
                    851:                                goto bad;
                    852:                        }
                    853:                        ntime = iptime();
                    854:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    855:                            sizeof(n_time));
                    856:                        ipt->ipt_ptr += sizeof(n_time);
                    857:                }
                    858:        }
                    859:        if (forward) {
1.26      thorpej   860:                if (ip_forwsrcrt == 0) {
                    861:                        type = ICMP_UNREACH;
                    862:                        code = ICMP_UNREACH_SRCFAIL;
                    863:                        goto bad;
                    864:                }
1.1       cgd       865:                ip_forward(m, 1);
                    866:                return (1);
1.13      mycroft   867:        }
                    868:        return (0);
1.1       cgd       869: bad:
1.13      mycroft   870:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
                    871:        icmp_error(m, type, code, 0, 0);
                    872:        ipstat.ips_badoptions++;
1.1       cgd       873:        return (1);
                    874: }
                    875:
                    876: /*
                    877:  * Given address of next destination (final or next hop),
                    878:  * return internet address info of interface to be used to get there.
                    879:  */
                    880: struct in_ifaddr *
                    881: ip_rtaddr(dst)
                    882:         struct in_addr dst;
                    883: {
                    884:        register struct sockaddr_in *sin;
                    885:
1.19      mycroft   886:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd       887:
1.35      mycroft   888:        if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) {
1.1       cgd       889:                if (ipforward_rt.ro_rt) {
                    890:                        RTFREE(ipforward_rt.ro_rt);
                    891:                        ipforward_rt.ro_rt = 0;
                    892:                }
                    893:                sin->sin_family = AF_INET;
                    894:                sin->sin_len = sizeof(*sin);
                    895:                sin->sin_addr = dst;
                    896:
                    897:                rtalloc(&ipforward_rt);
                    898:        }
                    899:        if (ipforward_rt.ro_rt == 0)
                    900:                return ((struct in_ifaddr *)0);
1.19      mycroft   901:        return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1       cgd       902: }
                    903:
                    904: /*
                    905:  * Save incoming source route for use in replies,
                    906:  * to be picked up later by ip_srcroute if the receiver is interested.
                    907:  */
1.13      mycroft   908: void
1.1       cgd       909: save_rte(option, dst)
                    910:        u_char *option;
                    911:        struct in_addr dst;
                    912: {
                    913:        unsigned olen;
                    914:
                    915:        olen = option[IPOPT_OLEN];
                    916: #ifdef DIAGNOSTIC
                    917:        if (ipprintfs)
1.39      christos  918:                printf("save_rte: olen %d\n", olen);
1.1       cgd       919: #endif
                    920:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    921:                return;
                    922:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    923:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    924:        ip_srcrt.dst = dst;
                    925: }
                    926:
                    927: /*
                    928:  * Retrieve incoming source route for use in replies,
                    929:  * in the same form used by setsockopt.
                    930:  * The first hop is placed before the options, will be removed later.
                    931:  */
                    932: struct mbuf *
                    933: ip_srcroute()
                    934: {
                    935:        register struct in_addr *p, *q;
                    936:        register struct mbuf *m;
                    937:
                    938:        if (ip_nhops == 0)
                    939:                return ((struct mbuf *)0);
                    940:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    941:        if (m == 0)
                    942:                return ((struct mbuf *)0);
                    943:
1.13      mycroft   944: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       945:
                    946:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    947:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    948:            OPTSIZ;
                    949: #ifdef DIAGNOSTIC
                    950:        if (ipprintfs)
1.39      christos  951:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
1.1       cgd       952: #endif
                    953:
                    954:        /*
                    955:         * First save first hop for return route
                    956:         */
                    957:        p = &ip_srcrt.route[ip_nhops - 1];
                    958:        *(mtod(m, struct in_addr *)) = *p--;
                    959: #ifdef DIAGNOSTIC
                    960:        if (ipprintfs)
1.39      christos  961:                printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1.1       cgd       962: #endif
                    963:
                    964:        /*
                    965:         * Copy option fields and padding (nop) to mbuf.
                    966:         */
                    967:        ip_srcrt.nop = IPOPT_NOP;
                    968:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    969:        bcopy((caddr_t)&ip_srcrt.nop,
                    970:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    971:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    972:            sizeof(struct in_addr) + OPTSIZ);
                    973: #undef OPTSIZ
                    974:        /*
                    975:         * Record return path as an IP source route,
                    976:         * reversing the path (pointers are now aligned).
                    977:         */
                    978:        while (p >= ip_srcrt.route) {
                    979: #ifdef DIAGNOSTIC
                    980:                if (ipprintfs)
1.39      christos  981:                        printf(" %x", ntohl(q->s_addr));
1.1       cgd       982: #endif
                    983:                *q++ = *p--;
                    984:        }
                    985:        /*
                    986:         * Last hop goes to final destination.
                    987:         */
                    988:        *q = ip_srcrt.dst;
                    989: #ifdef DIAGNOSTIC
                    990:        if (ipprintfs)
1.39      christos  991:                printf(" %x\n", ntohl(q->s_addr));
1.1       cgd       992: #endif
                    993:        return (m);
                    994: }
                    995:
                    996: /*
                    997:  * Strip out IP options, at higher
                    998:  * level protocol in the kernel.
                    999:  * Second argument is buffer to which options
                   1000:  * will be moved, and return value is their length.
                   1001:  * XXX should be deleted; last arg currently ignored.
                   1002:  */
1.8       mycroft  1003: void
1.1       cgd      1004: ip_stripoptions(m, mopt)
                   1005:        register struct mbuf *m;
                   1006:        struct mbuf *mopt;
                   1007: {
                   1008:        register int i;
                   1009:        struct ip *ip = mtod(m, struct ip *);
                   1010:        register caddr_t opts;
                   1011:        int olen;
                   1012:
                   1013:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                   1014:        opts = (caddr_t)(ip + 1);
                   1015:        i = m->m_len - (sizeof (struct ip) + olen);
                   1016:        bcopy(opts  + olen, opts, (unsigned)i);
                   1017:        m->m_len -= olen;
                   1018:        if (m->m_flags & M_PKTHDR)
                   1019:                m->m_pkthdr.len -= olen;
                   1020:        ip->ip_hl = sizeof(struct ip) >> 2;
                   1021: }
                   1022:
1.23      mycroft  1023: int inetctlerrmap[PRC_NCMDS] = {
1.1       cgd      1024:        0,              0,              0,              0,
                   1025:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                   1026:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                   1027:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                   1028:        0,              0,              0,              0,
                   1029:        ENOPROTOOPT
                   1030: };
                   1031:
                   1032: /*
                   1033:  * Forward a packet.  If some error occurs return the sender
                   1034:  * an icmp packet.  Note we can't always generate a meaningful
                   1035:  * icmp message because icmp doesn't have a large enough repertoire
                   1036:  * of codes and types.
                   1037:  *
                   1038:  * If not forwarding, just drop the packet.  This could be confusing
                   1039:  * if ipforwarding was zero but some routing protocol was advancing
                   1040:  * us as a gateway to somewhere.  However, we must let the routing
                   1041:  * protocol deal with that.
                   1042:  *
                   1043:  * The srcrt parameter indicates whether the packet is being forwarded
                   1044:  * via a source route.
                   1045:  */
1.13      mycroft  1046: void
1.1       cgd      1047: ip_forward(m, srcrt)
                   1048:        struct mbuf *m;
                   1049:        int srcrt;
                   1050: {
                   1051:        register struct ip *ip = mtod(m, struct ip *);
                   1052:        register struct sockaddr_in *sin;
                   1053:        register struct rtentry *rt;
1.28      christos 1054:        int error, type = 0, code = 0;
1.1       cgd      1055:        struct mbuf *mcopy;
1.13      mycroft  1056:        n_long dest;
                   1057:        struct ifnet *destifp;
1.1       cgd      1058:
1.13      mycroft  1059:        dest = 0;
1.1       cgd      1060: #ifdef DIAGNOSTIC
                   1061:        if (ipprintfs)
1.39      christos 1062:                printf("forward: src %x dst %x ttl %x\n",
1.35      mycroft  1063:                    ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl);
1.1       cgd      1064: #endif
                   1065:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1066:                ipstat.ips_cantforward++;
                   1067:                m_freem(m);
                   1068:                return;
                   1069:        }
                   1070:        HTONS(ip->ip_id);
                   1071:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1072:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1073:                return;
                   1074:        }
                   1075:        ip->ip_ttl -= IPTTLDEC;
                   1076:
1.19      mycroft  1077:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1078:        if ((rt = ipforward_rt.ro_rt) == 0 ||
1.35      mycroft  1079:            !in_hosteq(ip->ip_dst, sin->sin_addr)) {
1.1       cgd      1080:                if (ipforward_rt.ro_rt) {
                   1081:                        RTFREE(ipforward_rt.ro_rt);
                   1082:                        ipforward_rt.ro_rt = 0;
                   1083:                }
                   1084:                sin->sin_family = AF_INET;
1.35      mycroft  1085:                sin->sin_len = sizeof(struct sockaddr_in);
1.1       cgd      1086:                sin->sin_addr = ip->ip_dst;
                   1087:
                   1088:                rtalloc(&ipforward_rt);
                   1089:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1090:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1091:                        return;
                   1092:                }
                   1093:                rt = ipforward_rt.ro_rt;
                   1094:        }
                   1095:
                   1096:        /*
1.34      mycroft  1097:         * Save at most 68 bytes of the packet in case
1.1       cgd      1098:         * we need to generate an ICMP message to the src.
                   1099:         */
1.34      mycroft  1100:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 68));
1.1       cgd      1101:
                   1102:        /*
                   1103:         * If forwarding packet using same interface that it came in on,
                   1104:         * perhaps should send a redirect to sender to shortcut a hop.
                   1105:         * Only send redirect if source is sending directly to us,
                   1106:         * and if packet was not source routed (or has any options).
                   1107:         * Also, don't send redirect if forwarding using a default route
                   1108:         * or a route modified by a redirect.
                   1109:         */
                   1110:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1111:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1.35      mycroft  1112:            !in_nullhost(satosin(rt_key(rt))->sin_addr) &&
1.1       cgd      1113:            ipsendredirects && !srcrt) {
1.19      mycroft  1114:                if (rt->rt_ifa &&
                   1115:                    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
                   1116:                    ifatoia(rt->rt_ifa)->ia_subnet) {
1.1       cgd      1117:                    if (rt->rt_flags & RTF_GATEWAY)
1.13      mycroft  1118:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1119:                    else
1.13      mycroft  1120:                        dest = ip->ip_dst.s_addr;
                   1121:                    /* Router requirements says to only send host redirects */
1.1       cgd      1122:                    type = ICMP_REDIRECT;
1.13      mycroft  1123:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1124: #ifdef DIAGNOSTIC
                   1125:                    if (ipprintfs)
1.39      christos 1126:                        printf("redirect (%d) to %x\n", code, (u_int32_t)dest);
1.1       cgd      1127: #endif
                   1128:                }
                   1129:        }
                   1130:
1.27      thorpej  1131:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
                   1132:            (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0);
1.1       cgd      1133:        if (error)
                   1134:                ipstat.ips_cantforward++;
                   1135:        else {
                   1136:                ipstat.ips_forward++;
                   1137:                if (type)
                   1138:                        ipstat.ips_redirectsent++;
                   1139:                else {
                   1140:                        if (mcopy)
                   1141:                                m_freem(mcopy);
                   1142:                        return;
                   1143:                }
                   1144:        }
                   1145:        if (mcopy == NULL)
                   1146:                return;
1.13      mycroft  1147:        destifp = NULL;
                   1148:
1.1       cgd      1149:        switch (error) {
                   1150:
                   1151:        case 0:                         /* forwarded, but need redirect */
                   1152:                /* type, code set above */
                   1153:                break;
                   1154:
                   1155:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1156:        case EHOSTUNREACH:
                   1157:        case ENETDOWN:
                   1158:        case EHOSTDOWN:
                   1159:        default:
                   1160:                type = ICMP_UNREACH;
                   1161:                code = ICMP_UNREACH_HOST;
                   1162:                break;
                   1163:
                   1164:        case EMSGSIZE:
                   1165:                type = ICMP_UNREACH;
                   1166:                code = ICMP_UNREACH_NEEDFRAG;
1.13      mycroft  1167:                if (ipforward_rt.ro_rt)
                   1168:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1169:                ipstat.ips_cantfrag++;
                   1170:                break;
                   1171:
                   1172:        case ENOBUFS:
                   1173:                type = ICMP_SOURCEQUENCH;
                   1174:                code = 0;
                   1175:                break;
                   1176:        }
1.13      mycroft  1177:        icmp_error(mcopy, type, code, dest, destifp);
1.44      thorpej  1178: }
                   1179:
                   1180: void
                   1181: ip_savecontrol(inp, mp, ip, m)
                   1182:        register struct inpcb *inp;
                   1183:        register struct mbuf **mp;
                   1184:        register struct ip *ip;
                   1185:        register struct mbuf *m;
                   1186: {
                   1187:
                   1188:        if (inp->inp_socket->so_options & SO_TIMESTAMP) {
                   1189:                struct timeval tv;
                   1190:
                   1191:                microtime(&tv);
                   1192:                *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
                   1193:                    SCM_TIMESTAMP, SOL_SOCKET);
                   1194:                if (*mp)
                   1195:                        mp = &(*mp)->m_next;
                   1196:        }
                   1197:        if (inp->inp_flags & INP_RECVDSTADDR) {
                   1198:                *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
                   1199:                    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
                   1200:                if (*mp)
                   1201:                        mp = &(*mp)->m_next;
                   1202:        }
                   1203: #ifdef notyet
                   1204:        /*
                   1205:         * XXX
                   1206:         * Moving these out of udp_input() made them even more broken
                   1207:         * than they already were.
                   1208:         *      - fenner@parc.xerox.com
                   1209:         */
                   1210:        /* options were tossed already */
                   1211:        if (inp->inp_flags & INP_RECVOPTS) {
                   1212:                *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
                   1213:                    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
                   1214:                if (*mp)
                   1215:                        mp = &(*mp)->m_next;
                   1216:        }
                   1217:        /* ip_srcroute doesn't do what we want here, need to fix */
                   1218:        if (inp->inp_flags & INP_RECVRETOPTS) {
                   1219:                *mp = sbcreatecontrol((caddr_t) ip_srcroute(),
                   1220:                    sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
                   1221:                if (*mp)
                   1222:                        mp = &(*mp)->m_next;
                   1223:        }
                   1224: #endif
                   1225:        if (inp->inp_flags & INP_RECVIF) {
                   1226:                struct sockaddr_dl sdl;
                   1227:
                   1228:                sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]);
                   1229:                sdl.sdl_family = AF_LINK;
                   1230:                sdl.sdl_index = m->m_pkthdr.rcvif ?
                   1231:                    m->m_pkthdr.rcvif->if_index : 0;
                   1232:                sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0;
                   1233:                *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len,
                   1234:                    IP_RECVIF, IPPROTO_IP);
                   1235:                if (*mp)
                   1236:                        mp = &(*mp)->m_next;
                   1237:        }
1.13      mycroft  1238: }
                   1239:
                   1240: int
                   1241: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1242:        int *name;
                   1243:        u_int namelen;
                   1244:        void *oldp;
                   1245:        size_t *oldlenp;
                   1246:        void *newp;
                   1247:        size_t newlen;
                   1248: {
1.52      thorpej  1249:        extern int subnetsarelocal;
                   1250:
1.54      lukem    1251:        int error, old;
                   1252:
1.13      mycroft  1253:        /* All sysctl names at this level are terminal. */
                   1254:        if (namelen != 1)
                   1255:                return (ENOTDIR);
                   1256:
                   1257:        switch (name[0]) {
                   1258:        case IPCTL_FORWARDING:
                   1259:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
                   1260:        case IPCTL_SENDREDIRECTS:
                   1261:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1262:                        &ipsendredirects));
                   1263:        case IPCTL_DEFTTL:
                   1264:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
                   1265: #ifdef notyet
                   1266:        case IPCTL_DEFMTU:
                   1267:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
                   1268: #endif
1.26      thorpej  1269:        case IPCTL_FORWSRCRT:
1.47      cjs      1270:                /* Don't allow this to change in a secure environment.  */
1.26      thorpej  1271:                if (securelevel > 0)
1.46      cjs      1272:                        return (sysctl_rdint(oldp, oldlenp, newp,
                   1273:                            ip_forwsrcrt));
                   1274:                else
                   1275:                        return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1276:                            &ip_forwsrcrt));
1.27      thorpej  1277:        case IPCTL_DIRECTEDBCAST:
                   1278:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1279:                    &ip_directedbcast));
1.47      cjs      1280:        case IPCTL_ALLOWSRCRT:
                   1281:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1282:                    &ip_allowsrcrt));
1.52      thorpej  1283:        case IPCTL_SUBNETSARELOCAL:
                   1284:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1285:                    &subnetsarelocal));
1.53      kml      1286:        case IPCTL_MTUDISC:
1.54      lukem    1287:                return (sysctl_int(oldp, oldlenp, newp, newlen,
1.53      kml      1288:                    &ip_mtudisc));
1.54      lukem    1289:        case IPCTL_ANONPORTMIN:
                   1290:                old = anonportmin;
                   1291:                error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmin);
                   1292:                if (anonportmin >= anonportmax || anonportmin > 65535
                   1293: #ifndef IPNOPRIVPORTS
                   1294:                    || anonportmin < IPPORT_RESERVED
                   1295: #endif
                   1296:                    ) {
                   1297:                        anonportmin = old;
                   1298:                        return (EINVAL);
                   1299:                }
                   1300:                return (error);
                   1301:        case IPCTL_ANONPORTMAX:
                   1302:                old = anonportmax;
                   1303:                error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmax);
                   1304:                if (anonportmin >= anonportmax || anonportmax > 65535
                   1305: #ifndef IPNOPRIVPORTS
                   1306:                    || anonportmax < IPPORT_RESERVED
                   1307: #endif
                   1308:                    ) {
                   1309:                        anonportmax = old;
                   1310:                        return (EINVAL);
                   1311:                }
                   1312:                return (error);
1.13      mycroft  1313:        default:
                   1314:                return (EOPNOTSUPP);
                   1315:        }
                   1316:        /* NOTREACHED */
1.1       cgd      1317: }

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