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Annotation of src/sys/netinet/ip_input.c, Revision 1.54

1.54    ! lukem       1: /*     $NetBSD: ip_input.c,v 1.53 1997/10/18 21:18:31 kml Exp $        */
1.14      cgd         2:
1.1       cgd         3: /*
1.13      mycroft     4:  * Copyright (c) 1982, 1986, 1988, 1993
                      5:  *     The Regents of the University of California.  All rights reserved.
1.1       cgd         6:  *
                      7:  * Redistribution and use in source and binary forms, with or without
                      8:  * modification, are permitted provided that the following conditions
                      9:  * are met:
                     10:  * 1. Redistributions of source code must retain the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer.
                     12:  * 2. Redistributions in binary form must reproduce the above copyright
                     13:  *    notice, this list of conditions and the following disclaimer in the
                     14:  *    documentation and/or other materials provided with the distribution.
                     15:  * 3. All advertising materials mentioning features or use of this software
                     16:  *    must display the following acknowledgement:
                     17:  *     This product includes software developed by the University of
                     18:  *     California, Berkeley and its contributors.
                     19:  * 4. Neither the name of the University nor the names of its contributors
                     20:  *    may be used to endorse or promote products derived from this software
                     21:  *    without specific prior written permission.
                     22:  *
                     23:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     24:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     25:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     26:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     27:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     28:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     29:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     30:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     31:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     32:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     33:  * SUCH DAMAGE.
                     34:  *
1.14      cgd        35:  *     @(#)ip_input.c  8.2 (Berkeley) 1/4/94
1.1       cgd        36:  */
                     37:
1.5       mycroft    38: #include <sys/param.h>
                     39: #include <sys/systm.h>
                     40: #include <sys/malloc.h>
                     41: #include <sys/mbuf.h>
                     42: #include <sys/domain.h>
                     43: #include <sys/protosw.h>
                     44: #include <sys/socket.h>
1.44      thorpej    45: #include <sys/socketvar.h>
1.5       mycroft    46: #include <sys/errno.h>
                     47: #include <sys/time.h>
                     48: #include <sys/kernel.h>
1.28      christos   49: #include <sys/proc.h>
                     50:
                     51: #include <vm/vm.h>
                     52: #include <sys/sysctl.h>
1.1       cgd        53:
1.5       mycroft    54: #include <net/if.h>
1.44      thorpej    55: #include <net/if_dl.h>
1.5       mycroft    56: #include <net/route.h>
1.45      mrg        57: #include <net/pfil.h>
1.1       cgd        58:
1.5       mycroft    59: #include <netinet/in.h>
                     60: #include <netinet/in_systm.h>
                     61: #include <netinet/ip.h>
                     62: #include <netinet/in_pcb.h>
                     63: #include <netinet/in_var.h>
                     64: #include <netinet/ip_var.h>
                     65: #include <netinet/ip_icmp.h>
1.36      mrg        66:
1.44      thorpej    67: /* XXX should really put this in libkern.h */
                     68: #define        offsetof(type, member)  ((size_t)(&((type *)0)->member))
                     69:
1.1       cgd        70: #ifndef        IPFORWARDING
                     71: #ifdef GATEWAY
                     72: #define        IPFORWARDING    1       /* forward IP packets not for us */
                     73: #else /* GATEWAY */
                     74: #define        IPFORWARDING    0       /* don't forward IP packets not for us */
                     75: #endif /* GATEWAY */
                     76: #endif /* IPFORWARDING */
                     77: #ifndef        IPSENDREDIRECTS
                     78: #define        IPSENDREDIRECTS 1
                     79: #endif
1.26      thorpej    80: #ifndef IPFORWSRCRT
1.47      cjs        81: #define        IPFORWSRCRT     1       /* forward source-routed packets */
                     82: #endif
                     83: #ifndef IPALLOWSRCRT
1.48      mrg        84: #define        IPALLOWSRCRT    1       /* allow source-routed packets */
1.26      thorpej    85: #endif
1.53      kml        86: #ifndef IPMTUDISC
                     87: #define IPMTUDISC      0
                     88: #endif
                     89:
1.27      thorpej    90: /*
                     91:  * Note: DIRECTED_BROADCAST is handled this way so that previous
                     92:  * configuration using this option will Just Work.
                     93:  */
                     94: #ifndef IPDIRECTEDBCAST
                     95: #ifdef DIRECTED_BROADCAST
                     96: #define IPDIRECTEDBCAST        1
                     97: #else
                     98: #define        IPDIRECTEDBCAST 0
                     99: #endif /* DIRECTED_BROADCAST */
                    100: #endif /* IPDIRECTEDBCAST */
1.1       cgd       101: int    ipforwarding = IPFORWARDING;
                    102: int    ipsendredirects = IPSENDREDIRECTS;
1.13      mycroft   103: int    ip_defttl = IPDEFTTL;
1.26      thorpej   104: int    ip_forwsrcrt = IPFORWSRCRT;
1.27      thorpej   105: int    ip_directedbcast = IPDIRECTEDBCAST;
1.47      cjs       106: int    ip_allowsrcrt = IPALLOWSRCRT;
1.53      kml       107: int    ip_mtudisc = IPMTUDISC;
1.1       cgd       108: #ifdef DIAGNOSTIC
                    109: int    ipprintfs = 0;
                    110: #endif
                    111:
                    112: extern struct domain inetdomain;
                    113: extern struct protosw inetsw[];
                    114: u_char ip_protox[IPPROTO_MAX];
                    115: int    ipqmaxlen = IFQ_MAXLEN;
1.22      mycroft   116: struct in_ifaddrhead in_ifaddr;
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);
1.1       cgd       160: }
                    161:
                    162: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
                    163: struct route ipforward_rt;
                    164:
                    165: /*
                    166:  * Ip input routine.  Checksum and byte swap header.  If fragmented
                    167:  * try to reassemble.  Process options.  Pass to next level.
                    168:  */
1.8       mycroft   169: void
1.1       cgd       170: ipintr()
                    171: {
1.33      mrg       172:        register struct ip *ip = NULL;
1.1       cgd       173:        register struct mbuf *m;
                    174:        register struct ipq *fp;
                    175:        register struct in_ifaddr *ia;
1.25      cgd       176:        struct ipqent *ipqe;
1.35      mycroft   177:        int hlen = 0, mff, len, s;
1.36      mrg       178: #ifdef PFIL_HOOKS
1.33      mrg       179:        struct packet_filter_hook *pfh;
                    180:        struct mbuf *m0;
1.43      mrg       181:        int rv;
1.36      mrg       182: #endif /* PFIL_HOOKS */
1.1       cgd       183:
                    184: next:
                    185:        /*
                    186:         * Get next datagram off input queue and get IP header
                    187:         * in first mbuf.
                    188:         */
                    189:        s = splimp();
                    190:        IF_DEQUEUE(&ipintrq, m);
                    191:        splx(s);
1.13      mycroft   192:        if (m == 0)
1.1       cgd       193:                return;
                    194: #ifdef DIAGNOSTIC
                    195:        if ((m->m_flags & M_PKTHDR) == 0)
                    196:                panic("ipintr no HDR");
                    197: #endif
                    198:        /*
                    199:         * If no IP addresses have been set yet but the interfaces
                    200:         * are receiving, can't do anything with incoming packets yet.
                    201:         */
1.22      mycroft   202:        if (in_ifaddr.tqh_first == 0)
1.1       cgd       203:                goto bad;
                    204:        ipstat.ips_total++;
                    205:        if (m->m_len < sizeof (struct ip) &&
                    206:            (m = m_pullup(m, sizeof (struct ip))) == 0) {
                    207:                ipstat.ips_toosmall++;
                    208:                goto next;
                    209:        }
                    210:        ip = mtod(m, struct ip *);
1.13      mycroft   211:        if (ip->ip_v != IPVERSION) {
                    212:                ipstat.ips_badvers++;
                    213:                goto bad;
                    214:        }
1.1       cgd       215:        hlen = ip->ip_hl << 2;
                    216:        if (hlen < sizeof(struct ip)) { /* minimum header length */
                    217:                ipstat.ips_badhlen++;
                    218:                goto bad;
                    219:        }
                    220:        if (hlen > m->m_len) {
                    221:                if ((m = m_pullup(m, hlen)) == 0) {
                    222:                        ipstat.ips_badhlen++;
                    223:                        goto next;
                    224:                }
                    225:                ip = mtod(m, struct ip *);
                    226:        }
1.28      christos  227:        if ((ip->ip_sum = in_cksum(m, hlen)) != 0) {
1.1       cgd       228:                ipstat.ips_badsum++;
                    229:                goto bad;
                    230:        }
                    231:
                    232:        /*
                    233:         * Convert fields to host representation.
                    234:         */
                    235:        NTOHS(ip->ip_len);
                    236:        NTOHS(ip->ip_id);
                    237:        NTOHS(ip->ip_off);
1.35      mycroft   238:        len = ip->ip_len;
1.1       cgd       239:
                    240:        /*
                    241:         * Check that the amount of data in the buffers
                    242:         * is as at least much as the IP header would have us expect.
                    243:         * Trim mbufs if longer than we expect.
                    244:         * Drop packet if shorter than we expect.
                    245:         */
1.35      mycroft   246:        if (m->m_pkthdr.len < len) {
1.1       cgd       247:                ipstat.ips_tooshort++;
                    248:                goto bad;
                    249:        }
1.35      mycroft   250:        if (m->m_pkthdr.len > len) {
1.1       cgd       251:                if (m->m_len == m->m_pkthdr.len) {
1.35      mycroft   252:                        m->m_len = len;
                    253:                        m->m_pkthdr.len = len;
1.1       cgd       254:                } else
1.35      mycroft   255:                        m_adj(m, len - m->m_pkthdr.len);
1.1       cgd       256:        }
                    257:
1.36      mrg       258: #ifdef PFIL_HOOKS
1.33      mrg       259:        /*
                    260:         * Run through list of hooks for input packets.
                    261:         */
                    262:        m0 = m;
                    263:        for (pfh = pfil_hook_get(PFIL_IN); pfh; pfh = pfh->pfil_link.le_next)
                    264:                if (pfh->pfil_func) {
1.43      mrg       265:                        rv = pfh->pfil_func(ip, hlen, m->m_pkthdr.rcvif, 0, &m0);
                    266:                        if (rv)
1.40      veego     267:                                goto next;
1.49      christos  268:                        ip = mtod(m = m0, struct ip *);
1.33      mrg       269:                }
1.36      mrg       270: #endif /* PFIL_HOOKS */
1.33      mrg       271:
1.1       cgd       272:        /*
                    273:         * Process options and, if not destined for us,
                    274:         * ship it on.  ip_dooptions returns 1 when an
                    275:         * error was detected (causing an icmp message
                    276:         * to be sent and the original packet to be freed).
                    277:         */
                    278:        ip_nhops = 0;           /* for source routed packets */
                    279:        if (hlen > sizeof (struct ip) && ip_dooptions(m))
                    280:                goto next;
                    281:
                    282:        /*
                    283:         * Check our list of addresses, to see if the packet is for us.
                    284:         */
1.22      mycroft   285:        for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
1.35      mycroft   286:                if (in_hosteq(ip->ip_dst, ia->ia_addr.sin_addr))
1.1       cgd       287:                        goto ours;
1.27      thorpej   288:                if (((ip_directedbcast == 0) || (ip_directedbcast &&
                    289:                    ia->ia_ifp == m->m_pkthdr.rcvif)) &&
1.1       cgd       290:                    (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.35      mycroft   291:                        if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
                    292:                            in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
1.20      mycroft   293:                            /*
                    294:                             * Look for all-0's host part (old broadcast addr),
                    295:                             * either for subnet or net.
                    296:                             */
                    297:                            ip->ip_dst.s_addr == ia->ia_subnet ||
1.18      mycroft   298:                            ip->ip_dst.s_addr == ia->ia_net)
1.1       cgd       299:                                goto ours;
                    300:                }
1.51      gwr       301:                /*
                    302:                 * An interface with IP address zero accepts
                    303:                 * all packets that arrive on that interface.
                    304:                 */
                    305:                if ((ia->ia_ifp == m->m_pkthdr.rcvif) &&
                    306:                    in_nullhost(ia->ia_addr.sin_addr))
                    307:                        goto ours;
1.1       cgd       308:        }
1.18      mycroft   309:        if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4       hpeyerl   310:                struct in_multi *inm;
                    311: #ifdef MROUTING
                    312:                extern struct socket *ip_mrouter;
1.10      brezak    313:
                    314:                if (m->m_flags & M_EXT) {
                    315:                        if ((m = m_pullup(m, hlen)) == 0) {
                    316:                                ipstat.ips_toosmall++;
                    317:                                goto next;
                    318:                        }
                    319:                        ip = mtod(m, struct ip *);
                    320:                }
1.4       hpeyerl   321:
                    322:                if (ip_mrouter) {
                    323:                        /*
                    324:                         * If we are acting as a multicast router, all
                    325:                         * incoming multicast packets are passed to the
                    326:                         * kernel-level multicast forwarding function.
                    327:                         * The packet is returned (relatively) intact; if
                    328:                         * ip_mforward() returns a non-zero value, the packet
                    329:                         * must be discarded, else it may be accepted below.
                    330:                         *
                    331:                         * (The IP ident field is put in the same byte order
                    332:                         * as expected when ip_mforward() is called from
                    333:                         * ip_output().)
                    334:                         */
                    335:                        ip->ip_id = htons(ip->ip_id);
1.13      mycroft   336:                        if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
                    337:                                ipstat.ips_cantforward++;
1.4       hpeyerl   338:                                m_freem(m);
                    339:                                goto next;
                    340:                        }
                    341:                        ip->ip_id = ntohs(ip->ip_id);
                    342:
                    343:                        /*
                    344:                         * The process-level routing demon needs to receive
                    345:                         * all multicast IGMP packets, whether or not this
                    346:                         * host belongs to their destination groups.
                    347:                         */
                    348:                        if (ip->ip_p == IPPROTO_IGMP)
                    349:                                goto ours;
1.13      mycroft   350:                        ipstat.ips_forward++;
1.4       hpeyerl   351:                }
                    352: #endif
                    353:                /*
                    354:                 * See if we belong to the destination multicast group on the
                    355:                 * arrival interface.
                    356:                 */
                    357:                IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
                    358:                if (inm == NULL) {
1.13      mycroft   359:                        ipstat.ips_cantforward++;
1.4       hpeyerl   360:                        m_freem(m);
                    361:                        goto next;
                    362:                }
                    363:                goto ours;
                    364:        }
1.19      mycroft   365:        if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
1.35      mycroft   366:            in_nullhost(ip->ip_dst))
1.1       cgd       367:                goto ours;
                    368:
                    369:        /*
                    370:         * Not for us; forward if possible and desirable.
                    371:         */
                    372:        if (ipforwarding == 0) {
                    373:                ipstat.ips_cantforward++;
                    374:                m_freem(m);
                    375:        } else
                    376:                ip_forward(m, 0);
                    377:        goto next;
                    378:
                    379: ours:
                    380:        /*
                    381:         * If offset or IP_MF are set, must reassemble.
                    382:         * Otherwise, nothing need be done.
                    383:         * (We could look in the reassembly queue to see
                    384:         * if the packet was previously fragmented,
                    385:         * but it's not worth the time; just let them time out.)
                    386:         */
1.37      perry     387:        if (ip->ip_off & ~(IP_DF|IP_RF)) {
1.1       cgd       388:                /*
                    389:                 * Look for queue of fragments
                    390:                 * of this datagram.
                    391:                 */
1.25      cgd       392:                for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1       cgd       393:                        if (ip->ip_id == fp->ipq_id &&
1.35      mycroft   394:                            in_hosteq(ip->ip_src, fp->ipq_src) &&
                    395:                            in_hosteq(ip->ip_dst, fp->ipq_dst) &&
1.1       cgd       396:                            ip->ip_p == fp->ipq_p)
                    397:                                goto found;
                    398:                fp = 0;
                    399: found:
                    400:
                    401:                /*
                    402:                 * Adjust ip_len to not reflect header,
1.25      cgd       403:                 * set ipqe_mff if more fragments are expected,
1.1       cgd       404:                 * convert offset of this to bytes.
                    405:                 */
                    406:                ip->ip_len -= hlen;
1.25      cgd       407:                mff = (ip->ip_off & IP_MF) != 0;
                    408:                if (mff) {
1.16      cgd       409:                        /*
                    410:                         * Make sure that fragments have a data length
                    411:                         * that's a non-zero multiple of 8 bytes.
                    412:                         */
1.17      cgd       413:                        if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16      cgd       414:                                ipstat.ips_badfrags++;
                    415:                                goto bad;
                    416:                        }
                    417:                }
1.1       cgd       418:                ip->ip_off <<= 3;
                    419:
                    420:                /*
                    421:                 * If datagram marked as having more fragments
                    422:                 * or if this is not the first fragment,
                    423:                 * attempt reassembly; if it succeeds, proceed.
                    424:                 */
1.25      cgd       425:                if (mff || ip->ip_off) {
1.1       cgd       426:                        ipstat.ips_fragments++;
1.25      cgd       427:                        MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent),
                    428:                            M_IPQ, M_NOWAIT);
                    429:                        if (ipqe == NULL) {
                    430:                                ipstat.ips_rcvmemdrop++;
                    431:                                goto bad;
                    432:                        }
                    433:                        ipqe->ipqe_mff = mff;
1.50      thorpej   434:                        ipqe->ipqe_m = m;
1.25      cgd       435:                        ipqe->ipqe_ip = ip;
1.50      thorpej   436:                        m = ip_reass(ipqe, fp);
                    437:                        if (m == 0)
1.1       cgd       438:                                goto next;
1.13      mycroft   439:                        ipstat.ips_reassembled++;
1.50      thorpej   440:                        ip = mtod(m, struct ip *);
1.1       cgd       441:                } else
                    442:                        if (fp)
                    443:                                ip_freef(fp);
                    444:        } else
                    445:                ip->ip_len -= hlen;
                    446:
                    447:        /*
                    448:         * Switch out to protocol's input routine.
                    449:         */
                    450:        ipstat.ips_delivered++;
                    451:        (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
                    452:        goto next;
                    453: bad:
                    454:        m_freem(m);
                    455:        goto next;
                    456: }
                    457:
                    458: /*
                    459:  * Take incoming datagram fragment and try to
                    460:  * reassemble it into whole datagram.  If a chain for
                    461:  * reassembly of this datagram already exists, then it
                    462:  * is given as fp; otherwise have to make a chain.
                    463:  */
1.50      thorpej   464: struct mbuf *
1.25      cgd       465: ip_reass(ipqe, fp)
                    466:        register struct ipqent *ipqe;
1.1       cgd       467:        register struct ipq *fp;
                    468: {
1.50      thorpej   469:        register struct mbuf *m = ipqe->ipqe_m;
1.25      cgd       470:        register struct ipqent *nq, *p, *q;
                    471:        struct ip *ip;
1.1       cgd       472:        struct mbuf *t;
1.25      cgd       473:        int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1       cgd       474:        int i, next;
                    475:
                    476:        /*
                    477:         * Presence of header sizes in mbufs
                    478:         * would confuse code below.
                    479:         */
                    480:        m->m_data += hlen;
                    481:        m->m_len -= hlen;
                    482:
                    483:        /*
                    484:         * If first fragment to arrive, create a reassembly queue.
                    485:         */
                    486:        if (fp == 0) {
1.50      thorpej   487:                MALLOC(fp, struct ipq *, sizeof (struct ipq),
                    488:                    M_FTABLE, M_NOWAIT);
                    489:                if (fp == NULL)
1.1       cgd       490:                        goto dropfrag;
1.25      cgd       491:                LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1       cgd       492:                fp->ipq_ttl = IPFRAGTTL;
1.25      cgd       493:                fp->ipq_p = ipqe->ipqe_ip->ip_p;
                    494:                fp->ipq_id = ipqe->ipqe_ip->ip_id;
                    495:                LIST_INIT(&fp->ipq_fragq);
                    496:                fp->ipq_src = ipqe->ipqe_ip->ip_src;
                    497:                fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
                    498:                p = NULL;
1.1       cgd       499:                goto insert;
                    500:        }
                    501:
                    502:        /*
                    503:         * Find a segment which begins after this one does.
                    504:         */
1.25      cgd       505:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    506:            p = q, q = q->ipqe_q.le_next)
                    507:                if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1       cgd       508:                        break;
                    509:
                    510:        /*
                    511:         * If there is a preceding segment, it may provide some of
                    512:         * our data already.  If so, drop the data from the incoming
                    513:         * segment.  If it provides all of our data, drop us.
                    514:         */
1.25      cgd       515:        if (p != NULL) {
                    516:                i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
                    517:                    ipqe->ipqe_ip->ip_off;
1.1       cgd       518:                if (i > 0) {
1.25      cgd       519:                        if (i >= ipqe->ipqe_ip->ip_len)
1.1       cgd       520:                                goto dropfrag;
1.50      thorpej   521:                        m_adj(ipqe->ipqe_m, i);
1.25      cgd       522:                        ipqe->ipqe_ip->ip_off += i;
                    523:                        ipqe->ipqe_ip->ip_len -= i;
1.1       cgd       524:                }
                    525:        }
                    526:
                    527:        /*
                    528:         * While we overlap succeeding segments trim them or,
                    529:         * if they are completely covered, dequeue them.
                    530:         */
1.25      cgd       531:        for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
                    532:            q->ipqe_ip->ip_off; q = nq) {
                    533:                i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
                    534:                    q->ipqe_ip->ip_off;
                    535:                if (i < q->ipqe_ip->ip_len) {
                    536:                        q->ipqe_ip->ip_len -= i;
                    537:                        q->ipqe_ip->ip_off += i;
1.50      thorpej   538:                        m_adj(q->ipqe_m, i);
1.1       cgd       539:                        break;
                    540:                }
1.25      cgd       541:                nq = q->ipqe_q.le_next;
1.50      thorpej   542:                m_freem(q->ipqe_m);
1.25      cgd       543:                LIST_REMOVE(q, ipqe_q);
                    544:                FREE(q, M_IPQ);
1.1       cgd       545:        }
                    546:
                    547: insert:
                    548:        /*
                    549:         * Stick new segment in its place;
                    550:         * check for complete reassembly.
                    551:         */
1.25      cgd       552:        if (p == NULL) {
                    553:                LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
                    554:        } else {
                    555:                LIST_INSERT_AFTER(p, ipqe, ipqe_q);
                    556:        }
1.1       cgd       557:        next = 0;
1.25      cgd       558:        for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
                    559:            p = q, q = q->ipqe_q.le_next) {
                    560:                if (q->ipqe_ip->ip_off != next)
1.1       cgd       561:                        return (0);
1.25      cgd       562:                next += q->ipqe_ip->ip_len;
1.1       cgd       563:        }
1.25      cgd       564:        if (p->ipqe_mff)
1.1       cgd       565:                return (0);
                    566:
                    567:        /*
1.41      thorpej   568:         * Reassembly is complete.  Check for a bogus message size and
                    569:         * concatenate fragments.
1.1       cgd       570:         */
1.25      cgd       571:        q = fp->ipq_fragq.lh_first;
                    572:        ip = q->ipqe_ip;
1.41      thorpej   573:        if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) {
                    574:                ipstat.ips_toolong++;
                    575:                ip_freef(fp);
                    576:                return (0);
                    577:        }
1.50      thorpej   578:        m = q->ipqe_m;
1.1       cgd       579:        t = m->m_next;
                    580:        m->m_next = 0;
                    581:        m_cat(m, t);
1.25      cgd       582:        nq = q->ipqe_q.le_next;
                    583:        FREE(q, M_IPQ);
                    584:        for (q = nq; q != NULL; q = nq) {
1.50      thorpej   585:                t = q->ipqe_m;
1.25      cgd       586:                nq = q->ipqe_q.le_next;
                    587:                FREE(q, M_IPQ);
1.1       cgd       588:                m_cat(m, t);
                    589:        }
                    590:
                    591:        /*
                    592:         * Create header for new ip packet by
                    593:         * modifying header of first packet;
                    594:         * dequeue and discard fragment reassembly header.
                    595:         * Make header visible.
                    596:         */
                    597:        ip->ip_len = next;
1.25      cgd       598:        ip->ip_src = fp->ipq_src;
                    599:        ip->ip_dst = fp->ipq_dst;
                    600:        LIST_REMOVE(fp, ipq_q);
1.50      thorpej   601:        FREE(fp, M_FTABLE);
1.1       cgd       602:        m->m_len += (ip->ip_hl << 2);
                    603:        m->m_data -= (ip->ip_hl << 2);
                    604:        /* some debugging cruft by sklower, below, will go away soon */
                    605:        if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
                    606:                register int plen = 0;
1.50      thorpej   607:                for (t = m; t; t = t->m_next)
                    608:                        plen += t->m_len;
                    609:                m->m_pkthdr.len = plen;
1.1       cgd       610:        }
1.50      thorpej   611:        return (m);
1.1       cgd       612:
                    613: dropfrag:
                    614:        ipstat.ips_fragdropped++;
                    615:        m_freem(m);
1.25      cgd       616:        FREE(ipqe, M_IPQ);
1.1       cgd       617:        return (0);
                    618: }
                    619:
                    620: /*
                    621:  * Free a fragment reassembly header and all
                    622:  * associated datagrams.
                    623:  */
1.8       mycroft   624: void
1.1       cgd       625: ip_freef(fp)
                    626:        struct ipq *fp;
                    627: {
1.25      cgd       628:        register struct ipqent *q, *p;
1.1       cgd       629:
1.25      cgd       630:        for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
                    631:                p = q->ipqe_q.le_next;
1.50      thorpej   632:                m_freem(q->ipqe_m);
1.25      cgd       633:                LIST_REMOVE(q, ipqe_q);
                    634:                FREE(q, M_IPQ);
1.1       cgd       635:        }
1.25      cgd       636:        LIST_REMOVE(fp, ipq_q);
1.50      thorpej   637:        FREE(fp, M_FTABLE);
1.1       cgd       638: }
                    639:
                    640: /*
                    641:  * IP timer processing;
                    642:  * if a timer expires on a reassembly
                    643:  * queue, discard it.
                    644:  */
1.8       mycroft   645: void
1.1       cgd       646: ip_slowtimo()
                    647: {
1.25      cgd       648:        register struct ipq *fp, *nfp;
1.24      mycroft   649:        int s = splsoftnet();
1.1       cgd       650:
1.25      cgd       651:        for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
                    652:                nfp = fp->ipq_q.le_next;
                    653:                if (--fp->ipq_ttl == 0) {
1.1       cgd       654:                        ipstat.ips_fragtimeout++;
1.25      cgd       655:                        ip_freef(fp);
1.1       cgd       656:                }
                    657:        }
                    658:        splx(s);
                    659: }
                    660:
                    661: /*
                    662:  * Drain off all datagram fragments.
                    663:  */
1.8       mycroft   664: void
1.1       cgd       665: ip_drain()
                    666: {
                    667:
1.25      cgd       668:        while (ipq.lh_first != NULL) {
1.1       cgd       669:                ipstat.ips_fragdropped++;
1.25      cgd       670:                ip_freef(ipq.lh_first);
1.1       cgd       671:        }
                    672: }
                    673:
                    674: /*
                    675:  * Do option processing on a datagram,
                    676:  * possibly discarding it if bad options are encountered,
                    677:  * or forwarding it if source-routed.
                    678:  * Returns 1 if packet has been forwarded/freed,
                    679:  * 0 if the packet should be processed further.
                    680:  */
1.8       mycroft   681: int
1.1       cgd       682: ip_dooptions(m)
                    683:        struct mbuf *m;
                    684: {
                    685:        register struct ip *ip = mtod(m, struct ip *);
                    686:        register u_char *cp;
                    687:        register struct ip_timestamp *ipt;
                    688:        register struct in_ifaddr *ia;
                    689:        int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13      mycroft   690:        struct in_addr *sin, dst;
1.1       cgd       691:        n_time ntime;
                    692:
1.13      mycroft   693:        dst = ip->ip_dst;
1.1       cgd       694:        cp = (u_char *)(ip + 1);
                    695:        cnt = (ip->ip_hl << 2) - sizeof (struct ip);
                    696:        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                    697:                opt = cp[IPOPT_OPTVAL];
                    698:                if (opt == IPOPT_EOL)
                    699:                        break;
                    700:                if (opt == IPOPT_NOP)
                    701:                        optlen = 1;
                    702:                else {
                    703:                        optlen = cp[IPOPT_OLEN];
                    704:                        if (optlen <= 0 || optlen > cnt) {
                    705:                                code = &cp[IPOPT_OLEN] - (u_char *)ip;
                    706:                                goto bad;
                    707:                        }
                    708:                }
                    709:                switch (opt) {
                    710:
                    711:                default:
                    712:                        break;
                    713:
                    714:                /*
                    715:                 * Source routing with record.
                    716:                 * Find interface with current destination address.
                    717:                 * If none on this machine then drop if strictly routed,
                    718:                 * or do nothing if loosely routed.
                    719:                 * Record interface address and bring up next address
                    720:                 * component.  If strictly routed make sure next
                    721:                 * address is on directly accessible net.
                    722:                 */
                    723:                case IPOPT_LSRR:
                    724:                case IPOPT_SSRR:
1.47      cjs       725:                        if (ip_allowsrcrt == 0) {
                    726:                                type = ICMP_UNREACH;
                    727:                                code = ICMP_UNREACH_NET_PROHIB;
                    728:                                goto bad;
                    729:                        }
1.1       cgd       730:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    731:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    732:                                goto bad;
                    733:                        }
                    734:                        ipaddr.sin_addr = ip->ip_dst;
1.19      mycroft   735:                        ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1       cgd       736:                        if (ia == 0) {
                    737:                                if (opt == IPOPT_SSRR) {
                    738:                                        type = ICMP_UNREACH;
                    739:                                        code = ICMP_UNREACH_SRCFAIL;
                    740:                                        goto bad;
                    741:                                }
                    742:                                /*
                    743:                                 * Loose routing, and not at next destination
                    744:                                 * yet; nothing to do except forward.
                    745:                                 */
                    746:                                break;
                    747:                        }
                    748:                        off--;                  /* 0 origin */
                    749:                        if (off > optlen - sizeof(struct in_addr)) {
                    750:                                /*
                    751:                                 * End of source route.  Should be for us.
                    752:                                 */
                    753:                                save_rte(cp, ip->ip_src);
                    754:                                break;
                    755:                        }
                    756:                        /*
                    757:                         * locate outgoing interface
                    758:                         */
                    759:                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
                    760:                            sizeof(ipaddr.sin_addr));
                    761:                        if (opt == IPOPT_SSRR) {
                    762: #define        INA     struct in_ifaddr *
                    763: #define        SA      struct sockaddr *
1.29      mrg       764:                            ia = (INA)ifa_ifwithladdr((SA)&ipaddr);
1.1       cgd       765:                        } else
                    766:                                ia = ip_rtaddr(ipaddr.sin_addr);
                    767:                        if (ia == 0) {
                    768:                                type = ICMP_UNREACH;
                    769:                                code = ICMP_UNREACH_SRCFAIL;
                    770:                                goto bad;
                    771:                        }
                    772:                        ip->ip_dst = ipaddr.sin_addr;
1.20      mycroft   773:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       774:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    775:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13      mycroft   776:                        /*
                    777:                         * Let ip_intr's mcast routing check handle mcast pkts
                    778:                         */
1.18      mycroft   779:                        forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1       cgd       780:                        break;
                    781:
                    782:                case IPOPT_RR:
                    783:                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
                    784:                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;
                    785:                                goto bad;
                    786:                        }
                    787:                        /*
                    788:                         * If no space remains, ignore.
                    789:                         */
                    790:                        off--;                  /* 0 origin */
                    791:                        if (off > optlen - sizeof(struct in_addr))
                    792:                                break;
                    793:                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
                    794:                            sizeof(ipaddr.sin_addr));
                    795:                        /*
                    796:                         * locate outgoing interface; if we're the destination,
                    797:                         * use the incoming interface (should be same).
                    798:                         */
                    799:                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
                    800:                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
                    801:                                type = ICMP_UNREACH;
                    802:                                code = ICMP_UNREACH_HOST;
                    803:                                goto bad;
                    804:                        }
1.20      mycroft   805:                        bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       806:                            (caddr_t)(cp + off), sizeof(struct in_addr));
                    807:                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);
                    808:                        break;
                    809:
                    810:                case IPOPT_TS:
                    811:                        code = cp - (u_char *)ip;
                    812:                        ipt = (struct ip_timestamp *)cp;
                    813:                        if (ipt->ipt_len < 5)
                    814:                                goto bad;
1.15      cgd       815:                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1       cgd       816:                                if (++ipt->ipt_oflw == 0)
                    817:                                        goto bad;
                    818:                                break;
                    819:                        }
                    820:                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
                    821:                        switch (ipt->ipt_flg) {
                    822:
                    823:                        case IPOPT_TS_TSONLY:
                    824:                                break;
                    825:
                    826:                        case IPOPT_TS_TSANDADDR:
                    827:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    828:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    829:                                        goto bad;
1.13      mycroft   830:                                ipaddr.sin_addr = dst;
                    831:                                ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
                    832:                                                            m->m_pkthdr.rcvif);
                    833:                                if (ia == 0)
                    834:                                        continue;
1.20      mycroft   835:                                bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1       cgd       836:                                    (caddr_t)sin, sizeof(struct in_addr));
                    837:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    838:                                break;
                    839:
                    840:                        case IPOPT_TS_PRESPEC:
                    841:                                if (ipt->ipt_ptr + sizeof(n_time) +
                    842:                                    sizeof(struct in_addr) > ipt->ipt_len)
                    843:                                        goto bad;
                    844:                                bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
                    845:                                    sizeof(struct in_addr));
                    846:                                if (ifa_ifwithaddr((SA)&ipaddr) == 0)
                    847:                                        continue;
                    848:                                ipt->ipt_ptr += sizeof(struct in_addr);
                    849:                                break;
                    850:
                    851:                        default:
                    852:                                goto bad;
                    853:                        }
                    854:                        ntime = iptime();
                    855:                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
                    856:                            sizeof(n_time));
                    857:                        ipt->ipt_ptr += sizeof(n_time);
                    858:                }
                    859:        }
                    860:        if (forward) {
1.26      thorpej   861:                if (ip_forwsrcrt == 0) {
                    862:                        type = ICMP_UNREACH;
                    863:                        code = ICMP_UNREACH_SRCFAIL;
                    864:                        goto bad;
                    865:                }
1.1       cgd       866:                ip_forward(m, 1);
                    867:                return (1);
1.13      mycroft   868:        }
                    869:        return (0);
1.1       cgd       870: bad:
1.13      mycroft   871:        ip->ip_len -= ip->ip_hl << 2;   /* XXX icmp_error adds in hdr length */
                    872:        icmp_error(m, type, code, 0, 0);
                    873:        ipstat.ips_badoptions++;
1.1       cgd       874:        return (1);
                    875: }
                    876:
                    877: /*
                    878:  * Given address of next destination (final or next hop),
                    879:  * return internet address info of interface to be used to get there.
                    880:  */
                    881: struct in_ifaddr *
                    882: ip_rtaddr(dst)
                    883:         struct in_addr dst;
                    884: {
                    885:        register struct sockaddr_in *sin;
                    886:
1.19      mycroft   887:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd       888:
1.35      mycroft   889:        if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) {
1.1       cgd       890:                if (ipforward_rt.ro_rt) {
                    891:                        RTFREE(ipforward_rt.ro_rt);
                    892:                        ipforward_rt.ro_rt = 0;
                    893:                }
                    894:                sin->sin_family = AF_INET;
                    895:                sin->sin_len = sizeof(*sin);
                    896:                sin->sin_addr = dst;
                    897:
                    898:                rtalloc(&ipforward_rt);
                    899:        }
                    900:        if (ipforward_rt.ro_rt == 0)
                    901:                return ((struct in_ifaddr *)0);
1.19      mycroft   902:        return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1       cgd       903: }
                    904:
                    905: /*
                    906:  * Save incoming source route for use in replies,
                    907:  * to be picked up later by ip_srcroute if the receiver is interested.
                    908:  */
1.13      mycroft   909: void
1.1       cgd       910: save_rte(option, dst)
                    911:        u_char *option;
                    912:        struct in_addr dst;
                    913: {
                    914:        unsigned olen;
                    915:
                    916:        olen = option[IPOPT_OLEN];
                    917: #ifdef DIAGNOSTIC
                    918:        if (ipprintfs)
1.39      christos  919:                printf("save_rte: olen %d\n", olen);
1.1       cgd       920: #endif
                    921:        if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
                    922:                return;
                    923:        bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
                    924:        ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
                    925:        ip_srcrt.dst = dst;
                    926: }
                    927:
                    928: /*
                    929:  * Retrieve incoming source route for use in replies,
                    930:  * in the same form used by setsockopt.
                    931:  * The first hop is placed before the options, will be removed later.
                    932:  */
                    933: struct mbuf *
                    934: ip_srcroute()
                    935: {
                    936:        register struct in_addr *p, *q;
                    937:        register struct mbuf *m;
                    938:
                    939:        if (ip_nhops == 0)
                    940:                return ((struct mbuf *)0);
                    941:        m = m_get(M_DONTWAIT, MT_SOOPTS);
                    942:        if (m == 0)
                    943:                return ((struct mbuf *)0);
                    944:
1.13      mycroft   945: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1       cgd       946:
                    947:        /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
                    948:        m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
                    949:            OPTSIZ;
                    950: #ifdef DIAGNOSTIC
                    951:        if (ipprintfs)
1.39      christos  952:                printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
1.1       cgd       953: #endif
                    954:
                    955:        /*
                    956:         * First save first hop for return route
                    957:         */
                    958:        p = &ip_srcrt.route[ip_nhops - 1];
                    959:        *(mtod(m, struct in_addr *)) = *p--;
                    960: #ifdef DIAGNOSTIC
                    961:        if (ipprintfs)
1.39      christos  962:                printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1.1       cgd       963: #endif
                    964:
                    965:        /*
                    966:         * Copy option fields and padding (nop) to mbuf.
                    967:         */
                    968:        ip_srcrt.nop = IPOPT_NOP;
                    969:        ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
                    970:        bcopy((caddr_t)&ip_srcrt.nop,
                    971:            mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
                    972:        q = (struct in_addr *)(mtod(m, caddr_t) +
                    973:            sizeof(struct in_addr) + OPTSIZ);
                    974: #undef OPTSIZ
                    975:        /*
                    976:         * Record return path as an IP source route,
                    977:         * reversing the path (pointers are now aligned).
                    978:         */
                    979:        while (p >= ip_srcrt.route) {
                    980: #ifdef DIAGNOSTIC
                    981:                if (ipprintfs)
1.39      christos  982:                        printf(" %x", ntohl(q->s_addr));
1.1       cgd       983: #endif
                    984:                *q++ = *p--;
                    985:        }
                    986:        /*
                    987:         * Last hop goes to final destination.
                    988:         */
                    989:        *q = ip_srcrt.dst;
                    990: #ifdef DIAGNOSTIC
                    991:        if (ipprintfs)
1.39      christos  992:                printf(" %x\n", ntohl(q->s_addr));
1.1       cgd       993: #endif
                    994:        return (m);
                    995: }
                    996:
                    997: /*
                    998:  * Strip out IP options, at higher
                    999:  * level protocol in the kernel.
                   1000:  * Second argument is buffer to which options
                   1001:  * will be moved, and return value is their length.
                   1002:  * XXX should be deleted; last arg currently ignored.
                   1003:  */
1.8       mycroft  1004: void
1.1       cgd      1005: ip_stripoptions(m, mopt)
                   1006:        register struct mbuf *m;
                   1007:        struct mbuf *mopt;
                   1008: {
                   1009:        register int i;
                   1010:        struct ip *ip = mtod(m, struct ip *);
                   1011:        register caddr_t opts;
                   1012:        int olen;
                   1013:
                   1014:        olen = (ip->ip_hl<<2) - sizeof (struct ip);
                   1015:        opts = (caddr_t)(ip + 1);
                   1016:        i = m->m_len - (sizeof (struct ip) + olen);
                   1017:        bcopy(opts  + olen, opts, (unsigned)i);
                   1018:        m->m_len -= olen;
                   1019:        if (m->m_flags & M_PKTHDR)
                   1020:                m->m_pkthdr.len -= olen;
                   1021:        ip->ip_hl = sizeof(struct ip) >> 2;
                   1022: }
                   1023:
1.23      mycroft  1024: int inetctlerrmap[PRC_NCMDS] = {
1.1       cgd      1025:        0,              0,              0,              0,
                   1026:        0,              EMSGSIZE,       EHOSTDOWN,      EHOSTUNREACH,
                   1027:        EHOSTUNREACH,   EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
                   1028:        EMSGSIZE,       EHOSTUNREACH,   0,              0,
                   1029:        0,              0,              0,              0,
                   1030:        ENOPROTOOPT
                   1031: };
                   1032:
                   1033: /*
                   1034:  * Forward a packet.  If some error occurs return the sender
                   1035:  * an icmp packet.  Note we can't always generate a meaningful
                   1036:  * icmp message because icmp doesn't have a large enough repertoire
                   1037:  * of codes and types.
                   1038:  *
                   1039:  * If not forwarding, just drop the packet.  This could be confusing
                   1040:  * if ipforwarding was zero but some routing protocol was advancing
                   1041:  * us as a gateway to somewhere.  However, we must let the routing
                   1042:  * protocol deal with that.
                   1043:  *
                   1044:  * The srcrt parameter indicates whether the packet is being forwarded
                   1045:  * via a source route.
                   1046:  */
1.13      mycroft  1047: void
1.1       cgd      1048: ip_forward(m, srcrt)
                   1049:        struct mbuf *m;
                   1050:        int srcrt;
                   1051: {
                   1052:        register struct ip *ip = mtod(m, struct ip *);
                   1053:        register struct sockaddr_in *sin;
                   1054:        register struct rtentry *rt;
1.28      christos 1055:        int error, type = 0, code = 0;
1.1       cgd      1056:        struct mbuf *mcopy;
1.13      mycroft  1057:        n_long dest;
                   1058:        struct ifnet *destifp;
1.1       cgd      1059:
1.13      mycroft  1060:        dest = 0;
1.1       cgd      1061: #ifdef DIAGNOSTIC
                   1062:        if (ipprintfs)
1.39      christos 1063:                printf("forward: src %x dst %x ttl %x\n",
1.35      mycroft  1064:                    ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl);
1.1       cgd      1065: #endif
                   1066:        if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
                   1067:                ipstat.ips_cantforward++;
                   1068:                m_freem(m);
                   1069:                return;
                   1070:        }
                   1071:        HTONS(ip->ip_id);
                   1072:        if (ip->ip_ttl <= IPTTLDEC) {
1.13      mycroft  1073:                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1       cgd      1074:                return;
                   1075:        }
                   1076:        ip->ip_ttl -= IPTTLDEC;
                   1077:
1.19      mycroft  1078:        sin = satosin(&ipforward_rt.ro_dst);
1.1       cgd      1079:        if ((rt = ipforward_rt.ro_rt) == 0 ||
1.35      mycroft  1080:            !in_hosteq(ip->ip_dst, sin->sin_addr)) {
1.1       cgd      1081:                if (ipforward_rt.ro_rt) {
                   1082:                        RTFREE(ipforward_rt.ro_rt);
                   1083:                        ipforward_rt.ro_rt = 0;
                   1084:                }
                   1085:                sin->sin_family = AF_INET;
1.35      mycroft  1086:                sin->sin_len = sizeof(struct sockaddr_in);
1.1       cgd      1087:                sin->sin_addr = ip->ip_dst;
                   1088:
                   1089:                rtalloc(&ipforward_rt);
                   1090:                if (ipforward_rt.ro_rt == 0) {
1.13      mycroft  1091:                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1       cgd      1092:                        return;
                   1093:                }
                   1094:                rt = ipforward_rt.ro_rt;
                   1095:        }
                   1096:
                   1097:        /*
1.34      mycroft  1098:         * Save at most 68 bytes of the packet in case
1.1       cgd      1099:         * we need to generate an ICMP message to the src.
                   1100:         */
1.34      mycroft  1101:        mcopy = m_copy(m, 0, imin((int)ip->ip_len, 68));
1.1       cgd      1102:
                   1103:        /*
                   1104:         * If forwarding packet using same interface that it came in on,
                   1105:         * perhaps should send a redirect to sender to shortcut a hop.
                   1106:         * Only send redirect if source is sending directly to us,
                   1107:         * and if packet was not source routed (or has any options).
                   1108:         * Also, don't send redirect if forwarding using a default route
                   1109:         * or a route modified by a redirect.
                   1110:         */
                   1111:        if (rt->rt_ifp == m->m_pkthdr.rcvif &&
                   1112:            (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1.35      mycroft  1113:            !in_nullhost(satosin(rt_key(rt))->sin_addr) &&
1.1       cgd      1114:            ipsendredirects && !srcrt) {
1.19      mycroft  1115:                if (rt->rt_ifa &&
                   1116:                    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
                   1117:                    ifatoia(rt->rt_ifa)->ia_subnet) {
1.1       cgd      1118:                    if (rt->rt_flags & RTF_GATEWAY)
1.13      mycroft  1119:                        dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1       cgd      1120:                    else
1.13      mycroft  1121:                        dest = ip->ip_dst.s_addr;
                   1122:                    /* Router requirements says to only send host redirects */
1.1       cgd      1123:                    type = ICMP_REDIRECT;
1.13      mycroft  1124:                    code = ICMP_REDIRECT_HOST;
1.1       cgd      1125: #ifdef DIAGNOSTIC
                   1126:                    if (ipprintfs)
1.39      christos 1127:                        printf("redirect (%d) to %x\n", code, (u_int32_t)dest);
1.1       cgd      1128: #endif
                   1129:                }
                   1130:        }
                   1131:
1.27      thorpej  1132:        error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
                   1133:            (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0);
1.1       cgd      1134:        if (error)
                   1135:                ipstat.ips_cantforward++;
                   1136:        else {
                   1137:                ipstat.ips_forward++;
                   1138:                if (type)
                   1139:                        ipstat.ips_redirectsent++;
                   1140:                else {
                   1141:                        if (mcopy)
                   1142:                                m_freem(mcopy);
                   1143:                        return;
                   1144:                }
                   1145:        }
                   1146:        if (mcopy == NULL)
                   1147:                return;
1.13      mycroft  1148:        destifp = NULL;
                   1149:
1.1       cgd      1150:        switch (error) {
                   1151:
                   1152:        case 0:                         /* forwarded, but need redirect */
                   1153:                /* type, code set above */
                   1154:                break;
                   1155:
                   1156:        case ENETUNREACH:               /* shouldn't happen, checked above */
                   1157:        case EHOSTUNREACH:
                   1158:        case ENETDOWN:
                   1159:        case EHOSTDOWN:
                   1160:        default:
                   1161:                type = ICMP_UNREACH;
                   1162:                code = ICMP_UNREACH_HOST;
                   1163:                break;
                   1164:
                   1165:        case EMSGSIZE:
                   1166:                type = ICMP_UNREACH;
                   1167:                code = ICMP_UNREACH_NEEDFRAG;
1.13      mycroft  1168:                if (ipforward_rt.ro_rt)
                   1169:                        destifp = ipforward_rt.ro_rt->rt_ifp;
1.1       cgd      1170:                ipstat.ips_cantfrag++;
                   1171:                break;
                   1172:
                   1173:        case ENOBUFS:
                   1174:                type = ICMP_SOURCEQUENCH;
                   1175:                code = 0;
                   1176:                break;
                   1177:        }
1.13      mycroft  1178:        icmp_error(mcopy, type, code, dest, destifp);
1.44      thorpej  1179: }
                   1180:
                   1181: void
                   1182: ip_savecontrol(inp, mp, ip, m)
                   1183:        register struct inpcb *inp;
                   1184:        register struct mbuf **mp;
                   1185:        register struct ip *ip;
                   1186:        register struct mbuf *m;
                   1187: {
                   1188:
                   1189:        if (inp->inp_socket->so_options & SO_TIMESTAMP) {
                   1190:                struct timeval tv;
                   1191:
                   1192:                microtime(&tv);
                   1193:                *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
                   1194:                    SCM_TIMESTAMP, SOL_SOCKET);
                   1195:                if (*mp)
                   1196:                        mp = &(*mp)->m_next;
                   1197:        }
                   1198:        if (inp->inp_flags & INP_RECVDSTADDR) {
                   1199:                *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
                   1200:                    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
                   1201:                if (*mp)
                   1202:                        mp = &(*mp)->m_next;
                   1203:        }
                   1204: #ifdef notyet
                   1205:        /*
                   1206:         * XXX
                   1207:         * Moving these out of udp_input() made them even more broken
                   1208:         * than they already were.
                   1209:         *      - fenner@parc.xerox.com
                   1210:         */
                   1211:        /* options were tossed already */
                   1212:        if (inp->inp_flags & INP_RECVOPTS) {
                   1213:                *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
                   1214:                    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
                   1215:                if (*mp)
                   1216:                        mp = &(*mp)->m_next;
                   1217:        }
                   1218:        /* ip_srcroute doesn't do what we want here, need to fix */
                   1219:        if (inp->inp_flags & INP_RECVRETOPTS) {
                   1220:                *mp = sbcreatecontrol((caddr_t) ip_srcroute(),
                   1221:                    sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
                   1222:                if (*mp)
                   1223:                        mp = &(*mp)->m_next;
                   1224:        }
                   1225: #endif
                   1226:        if (inp->inp_flags & INP_RECVIF) {
                   1227:                struct sockaddr_dl sdl;
                   1228:
                   1229:                sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]);
                   1230:                sdl.sdl_family = AF_LINK;
                   1231:                sdl.sdl_index = m->m_pkthdr.rcvif ?
                   1232:                    m->m_pkthdr.rcvif->if_index : 0;
                   1233:                sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0;
                   1234:                *mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len,
                   1235:                    IP_RECVIF, IPPROTO_IP);
                   1236:                if (*mp)
                   1237:                        mp = &(*mp)->m_next;
                   1238:        }
1.13      mycroft  1239: }
                   1240:
                   1241: int
                   1242: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
                   1243:        int *name;
                   1244:        u_int namelen;
                   1245:        void *oldp;
                   1246:        size_t *oldlenp;
                   1247:        void *newp;
                   1248:        size_t newlen;
                   1249: {
1.52      thorpej  1250:        extern int subnetsarelocal;
                   1251:
1.54    ! lukem    1252:        int error, old;
        !          1253:
1.13      mycroft  1254:        /* All sysctl names at this level are terminal. */
                   1255:        if (namelen != 1)
                   1256:                return (ENOTDIR);
                   1257:
                   1258:        switch (name[0]) {
                   1259:        case IPCTL_FORWARDING:
                   1260:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
                   1261:        case IPCTL_SENDREDIRECTS:
                   1262:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1263:                        &ipsendredirects));
                   1264:        case IPCTL_DEFTTL:
                   1265:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
                   1266: #ifdef notyet
                   1267:        case IPCTL_DEFMTU:
                   1268:                return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
                   1269: #endif
1.26      thorpej  1270:        case IPCTL_FORWSRCRT:
1.47      cjs      1271:                /* Don't allow this to change in a secure environment.  */
1.26      thorpej  1272:                if (securelevel > 0)
1.46      cjs      1273:                        return (sysctl_rdint(oldp, oldlenp, newp,
                   1274:                            ip_forwsrcrt));
                   1275:                else
                   1276:                        return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1277:                            &ip_forwsrcrt));
1.27      thorpej  1278:        case IPCTL_DIRECTEDBCAST:
                   1279:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1280:                    &ip_directedbcast));
1.47      cjs      1281:        case IPCTL_ALLOWSRCRT:
                   1282:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1283:                    &ip_allowsrcrt));
1.52      thorpej  1284:        case IPCTL_SUBNETSARELOCAL:
                   1285:                return (sysctl_int(oldp, oldlenp, newp, newlen,
                   1286:                    &subnetsarelocal));
1.53      kml      1287:        case IPCTL_MTUDISC:
1.54    ! lukem    1288:                return (sysctl_int(oldp, oldlenp, newp, newlen,
1.53      kml      1289:                    &ip_mtudisc));
1.54    ! lukem    1290:        case IPCTL_ANONPORTMIN:
        !          1291:                old = anonportmin;
        !          1292:                error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmin);
        !          1293:                if (anonportmin >= anonportmax || anonportmin > 65535
        !          1294: #ifndef IPNOPRIVPORTS
        !          1295:                    || anonportmin < IPPORT_RESERVED
        !          1296: #endif
        !          1297:                    ) {
        !          1298:                        anonportmin = old;
        !          1299:                        return (EINVAL);
        !          1300:                }
        !          1301:                return (error);
        !          1302:        case IPCTL_ANONPORTMAX:
        !          1303:                old = anonportmax;
        !          1304:                error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmax);
        !          1305:                if (anonportmin >= anonportmax || anonportmax > 65535
        !          1306: #ifndef IPNOPRIVPORTS
        !          1307:                    || anonportmax < IPPORT_RESERVED
        !          1308: #endif
        !          1309:                    ) {
        !          1310:                        anonportmax = old;
        !          1311:                        return (EINVAL);
        !          1312:                }
        !          1313:                return (error);
1.13      mycroft  1314:        default:
                   1315:                return (EOPNOTSUPP);
                   1316:        }
                   1317:        /* NOTREACHED */
1.1       cgd      1318: }

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