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Annotation of Net2/netns/ns_input.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1984, 1985, 1986, 1987 Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms, with or without
        !             6:  * modification, are permitted provided that the following conditions
        !             7:  * are met:
        !             8:  * 1. Redistributions of source code must retain the above copyright
        !             9:  *    notice, this list of conditions and the following disclaimer.
        !            10:  * 2. Redistributions in binary form must reproduce the above copyright
        !            11:  *    notice, this list of conditions and the following disclaimer in the
        !            12:  *    documentation and/or other materials provided with the distribution.
        !            13:  * 3. All advertising materials mentioning features or use of this software
        !            14:  *    must display the following acknowledgement:
        !            15:  *     This product includes software developed by the University of
        !            16:  *     California, Berkeley and its contributors.
        !            17:  * 4. Neither the name of the University nor the names of its contributors
        !            18:  *    may be used to endorse or promote products derived from this software
        !            19:  *    without specific prior written permission.
        !            20:  *
        !            21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            31:  * SUCH DAMAGE.
        !            32:  *
        !            33:  *     @(#)ns_input.c  7.8 (Berkeley) 6/27/91
        !            34:  */
        !            35: 
        !            36: #include "param.h"
        !            37: #include "systm.h"
        !            38: #include "malloc.h"
        !            39: #include "mbuf.h"
        !            40: #include "domain.h"
        !            41: #include "protosw.h"
        !            42: #include "socket.h"
        !            43: #include "socketvar.h"
        !            44: #include "errno.h"
        !            45: #include "time.h"
        !            46: #include "kernel.h"
        !            47: 
        !            48: #include "../net/if.h"
        !            49: #include "../net/route.h"
        !            50: #include "../net/raw_cb.h"
        !            51: 
        !            52: #include "ns.h"
        !            53: #include "ns_if.h"
        !            54: #include "ns_pcb.h"
        !            55: #include "idp.h"
        !            56: #include "idp_var.h"
        !            57: #include "ns_error.h"
        !            58: 
        !            59: /*
        !            60:  * NS initialization.
        !            61:  */
        !            62: union ns_host  ns_thishost;
        !            63: union ns_host  ns_zerohost;
        !            64: union ns_host  ns_broadhost;
        !            65: union ns_net   ns_zeronet;
        !            66: union ns_net   ns_broadnet;
        !            67: struct sockaddr_ns ns_netmask, ns_hostmask;
        !            68: 
        !            69: static u_short allones[] = {-1, -1, -1};
        !            70: 
        !            71: struct nspcb nspcb;
        !            72: struct nspcb nsrawpcb;
        !            73: 
        !            74: struct ifqueue nsintrq;
        !            75: int    nsqmaxlen = IFQ_MAXLEN;
        !            76: 
        !            77: int    idpcksum = 1;
        !            78: long   ns_pexseq;
        !            79: 
        !            80: ns_init()
        !            81: {
        !            82:        extern struct timeval time;
        !            83: 
        !            84:        ns_broadhost = * (union ns_host *) allones;
        !            85:        ns_broadnet = * (union ns_net *) allones;
        !            86:        nspcb.nsp_next = nspcb.nsp_prev = &nspcb;
        !            87:        nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb;
        !            88:        nsintrq.ifq_maxlen = nsqmaxlen;
        !            89:        ns_pexseq = time.tv_usec;
        !            90:        ns_netmask.sns_len = 6;
        !            91:        ns_netmask.sns_addr.x_net = ns_broadnet;
        !            92:        ns_hostmask.sns_len = 12;
        !            93:        ns_hostmask.sns_addr.x_net = ns_broadnet;
        !            94:        ns_hostmask.sns_addr.x_host = ns_broadhost;
        !            95: }
        !            96: 
        !            97: /*
        !            98:  * Idp input routine.  Pass to next level.
        !            99:  */
        !           100: int nsintr_getpck = 0;
        !           101: int nsintr_swtch = 0;
        !           102: nsintr()
        !           103: {
        !           104:        register struct idp *idp;
        !           105:        register struct mbuf *m;
        !           106:        register struct nspcb *nsp;
        !           107:        register int i;
        !           108:        int len, s, error;
        !           109:        char oddpacketp;
        !           110: 
        !           111: next:
        !           112:        /*
        !           113:         * Get next datagram off input queue and get IDP header
        !           114:         * in first mbuf.
        !           115:         */
        !           116:        s = splimp();
        !           117:        IF_DEQUEUE(&nsintrq, m);
        !           118:        splx(s);
        !           119:        nsintr_getpck++;
        !           120:        if (m == 0)
        !           121:                return;
        !           122:        if ((m->m_flags & M_EXT || m->m_len < sizeof (struct idp)) &&
        !           123:            (m = m_pullup(m, sizeof (struct idp))) == 0) {
        !           124:                idpstat.idps_toosmall++;
        !           125:                goto next;
        !           126:        }
        !           127: 
        !           128:        /*
        !           129:         * Give any raw listeners a crack at the packet
        !           130:         */
        !           131:        for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
        !           132:                struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
        !           133:                if (m1) idp_input(m1, nsp);
        !           134:        }
        !           135: 
        !           136:        idp = mtod(m, struct idp *);
        !           137:        len = ntohs(idp->idp_len);
        !           138:        if (oddpacketp = len & 1) {
        !           139:                len++;          /* If this packet is of odd length,
        !           140:                                   preserve garbage byte for checksum */
        !           141:        }
        !           142: 
        !           143:        /*
        !           144:         * Check that the amount of data in the buffers
        !           145:         * is as at least much as the IDP header would have us expect.
        !           146:         * Trim mbufs if longer than we expect.
        !           147:         * Drop packet if shorter than we expect.
        !           148:         */
        !           149:        if (m->m_pkthdr.len < len) {
        !           150:                idpstat.idps_tooshort++;
        !           151:                goto bad;
        !           152:        }
        !           153:        if (m->m_pkthdr.len > len) {
        !           154:                if (m->m_len == m->m_pkthdr.len) {
        !           155:                        m->m_len = len;
        !           156:                        m->m_pkthdr.len = len;
        !           157:                } else
        !           158:                        m_adj(m, len - m->m_pkthdr.len);
        !           159:        }
        !           160:        if (idpcksum && ((i = idp->idp_sum)!=0xffff)) {
        !           161:                idp->idp_sum = 0;
        !           162:                if (i != (idp->idp_sum = ns_cksum(m, len))) {
        !           163:                        idpstat.idps_badsum++;
        !           164:                        idp->idp_sum = i;
        !           165:                        if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host))
        !           166:                                error = NS_ERR_BADSUM;
        !           167:                        else
        !           168:                                error = NS_ERR_BADSUM_T;
        !           169:                        ns_error(m, error, 0);
        !           170:                        goto next;
        !           171:                }
        !           172:        }
        !           173:        /*
        !           174:         * Is this a directed broadcast?
        !           175:         */
        !           176:        if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) {
        !           177:                if ((!ns_neteq(idp->idp_dna, idp->idp_sna)) &&
        !           178:                    (!ns_neteqnn(idp->idp_dna.x_net, ns_broadnet)) &&
        !           179:                    (!ns_neteqnn(idp->idp_sna.x_net, ns_zeronet)) &&
        !           180:                    (!ns_neteqnn(idp->idp_dna.x_net, ns_zeronet)) ) {
        !           181:                        /*
        !           182:                         * Look to see if I need to eat this packet.
        !           183:                         * Algorithm is to forward all young packets
        !           184:                         * and prematurely age any packets which will
        !           185:                         * by physically broadcasted.
        !           186:                         * Any very old packets eaten without forwarding
        !           187:                         * would die anyway.
        !           188:                         *
        !           189:                         * Suggestion of Bill Nesheim, Cornell U.
        !           190:                         */
        !           191:                        if (idp->idp_tc < NS_MAXHOPS) {
        !           192:                                idp_forward(m);
        !           193:                                goto next;
        !           194:                        }
        !           195:                }
        !           196:        /*
        !           197:         * Is this our packet? If not, forward.
        !           198:         */
        !           199:        } else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) {
        !           200:                idp_forward(m);
        !           201:                goto next;
        !           202:        }
        !           203:        /*
        !           204:         * Locate pcb for datagram.
        !           205:         */
        !           206:        nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD);
        !           207:        /*
        !           208:         * Switch out to protocol's input routine.
        !           209:         */
        !           210:        nsintr_swtch++;
        !           211:        if (nsp) {
        !           212:                if (oddpacketp) {
        !           213:                        m_adj(m, -1);
        !           214:                }
        !           215:                if ((nsp->nsp_flags & NSP_ALL_PACKETS)==0)
        !           216:                        switch (idp->idp_pt) {
        !           217: 
        !           218:                            case NSPROTO_SPP:
        !           219:                                    spp_input(m, nsp);
        !           220:                                    goto next;
        !           221: 
        !           222:                            case NSPROTO_ERROR:
        !           223:                                    ns_err_input(m);
        !           224:                                    goto next;
        !           225:                        }
        !           226:                idp_input(m, nsp);
        !           227:        } else {
        !           228:                ns_error(m, NS_ERR_NOSOCK, 0);
        !           229:        }
        !           230:        goto next;
        !           231: 
        !           232: bad:
        !           233:        m_freem(m);
        !           234:        goto next;
        !           235: }
        !           236: 
        !           237: u_char nsctlerrmap[PRC_NCMDS] = {
        !           238:        ECONNABORTED,   ECONNABORTED,   0,              0,
        !           239:        0,              0,              EHOSTDOWN,      EHOSTUNREACH,
        !           240:        ENETUNREACH,    EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
        !           241:        EMSGSIZE,       0,              0,              0,
        !           242:        0,              0,              0,              0
        !           243: };
        !           244: 
        !           245: int idp_donosocks = 1;
        !           246: 
        !           247: idp_ctlinput(cmd, arg)
        !           248:        int cmd;
        !           249:        caddr_t arg;
        !           250: {
        !           251:        struct ns_addr *ns;
        !           252:        struct nspcb *nsp;
        !           253:        struct ns_errp *errp;
        !           254:        int idp_abort();
        !           255:        extern struct nspcb *idp_drop();
        !           256:        int type;
        !           257: 
        !           258:        if (cmd < 0 || cmd > PRC_NCMDS)
        !           259:                return;
        !           260:        if (nsctlerrmap[cmd] == 0)
        !           261:                return;         /* XXX */
        !           262:        type = NS_ERR_UNREACH_HOST;
        !           263:        switch (cmd) {
        !           264:                struct sockaddr_ns *sns;
        !           265: 
        !           266:        case PRC_IFDOWN:
        !           267:        case PRC_HOSTDEAD:
        !           268:        case PRC_HOSTUNREACH:
        !           269:                sns = (struct sockaddr_ns *)arg;
        !           270:                if (sns->sns_family != AF_NS)
        !           271:                        return;
        !           272:                ns = &sns->sns_addr;
        !           273:                break;
        !           274: 
        !           275:        default:
        !           276:                errp = (struct ns_errp *)arg;
        !           277:                ns = &errp->ns_err_idp.idp_dna;
        !           278:                type = errp->ns_err_num;
        !           279:                type = ntohs((u_short)type);
        !           280:        }
        !           281:        switch (type) {
        !           282: 
        !           283:        case NS_ERR_UNREACH_HOST:
        !           284:                ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, (long)0);
        !           285:                break;
        !           286: 
        !           287:        case NS_ERR_NOSOCK:
        !           288:                nsp = ns_pcblookup(ns, errp->ns_err_idp.idp_sna.x_port,
        !           289:                        NS_WILDCARD);
        !           290:                if(nsp && idp_donosocks && ! ns_nullhost(nsp->nsp_faddr))
        !           291:                        (void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
        !           292:        }
        !           293: }
        !           294: 
        !           295: int    idpprintfs = 0;
        !           296: int    idpforwarding = 1;
        !           297: /*
        !           298:  * Forward a packet.  If some error occurs return the sender
        !           299:  * an error packet.  Note we can't always generate a meaningful
        !           300:  * error message because the NS errors don't have a large enough repetoire
        !           301:  * of codes and types.
        !           302:  */
        !           303: struct route idp_droute;
        !           304: struct route idp_sroute;
        !           305: 
        !           306: idp_forward(m)
        !           307: struct mbuf *m;
        !           308: {
        !           309:        register struct idp *idp = mtod(m, struct idp *);
        !           310:        register int error, type, code;
        !           311:        struct mbuf *mcopy = NULL;
        !           312:        int agedelta = 1;
        !           313:        int flags = NS_FORWARDING;
        !           314:        int ok_there = 0;
        !           315:        int ok_back = 0;
        !           316: 
        !           317:        if (idpprintfs) {
        !           318:                printf("forward: src ");
        !           319:                ns_printhost(&idp->idp_sna);
        !           320:                printf(", dst ");
        !           321:                ns_printhost(&idp->idp_dna);
        !           322:                printf("hop count %d\n", idp->idp_tc);
        !           323:        }
        !           324:        if (idpforwarding == 0) {
        !           325:                /* can't tell difference between net and host */
        !           326:                type = NS_ERR_UNREACH_HOST, code = 0;
        !           327:                goto senderror;
        !           328:        }
        !           329:        idp->idp_tc++;
        !           330:        if (idp->idp_tc > NS_MAXHOPS) {
        !           331:                type = NS_ERR_TOO_OLD, code = 0;
        !           332:                goto senderror;
        !           333:        }
        !           334:        /*
        !           335:         * Save at most 42 bytes of the packet in case
        !           336:         * we need to generate an NS error message to the src.
        !           337:         */
        !           338:        mcopy = m_copy(m, 0, imin((int)ntohs(idp->idp_len), 42));
        !           339: 
        !           340:        if ((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) {
        !           341:                type = NS_ERR_UNREACH_HOST, code = 0;
        !           342:                goto senderror;
        !           343:        }
        !           344:        /*
        !           345:         * Here we think about  forwarding  broadcast packets,
        !           346:         * so we try to insure that it doesn't go back out
        !           347:         * on the interface it came in on.  Also, if we
        !           348:         * are going to physically broadcast this, let us
        !           349:         * age the packet so we can eat it safely the second time around.
        !           350:         */
        !           351:        if (idp->idp_dna.x_host.c_host[0] & 0x1) {
        !           352:                struct ns_ifaddr *ia = ns_iaonnetof(&idp->idp_dna);
        !           353:                struct ifnet *ifp;
        !           354:                if (ia) {
        !           355:                        /* I'm gonna hafta eat this packet */
        !           356:                        agedelta += NS_MAXHOPS - idp->idp_tc;
        !           357:                        idp->idp_tc = NS_MAXHOPS;
        !           358:                }
        !           359:                if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) {
        !           360:                        /* error = ENETUNREACH; He'll never get it! */
        !           361:                        m_freem(m);
        !           362:                        goto cleanup;
        !           363:                }
        !           364:                if (idp_droute.ro_rt &&
        !           365:                    (ifp=idp_droute.ro_rt->rt_ifp) &&
        !           366:                    idp_sroute.ro_rt &&
        !           367:                    (ifp!=idp_sroute.ro_rt->rt_ifp)) {
        !           368:                        flags |= NS_ALLOWBROADCAST;
        !           369:                } else {
        !           370:                        type = NS_ERR_UNREACH_HOST, code = 0;
        !           371:                        goto senderror;
        !           372:                }
        !           373:        }
        !           374:        /* need to adjust checksum */
        !           375:        if (idp->idp_sum!=0xffff) {
        !           376:                union bytes {
        !           377:                        u_char c[4];
        !           378:                        u_short s[2];
        !           379:                        long l;
        !           380:                } x;
        !           381:                register int shift;
        !           382:                x.l = 0; x.c[0] = agedelta;
        !           383:                shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf;
        !           384:                x.l = idp->idp_sum + (x.s[0] << shift);
        !           385:                x.l = x.s[0] + x.s[1];
        !           386:                x.l = x.s[0] + x.s[1];
        !           387:                if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l;
        !           388:        }
        !           389:        if ((error = ns_output(m, &idp_droute, flags)) && 
        !           390:            (mcopy!=NULL)) {
        !           391:                idp = mtod(mcopy, struct idp *);
        !           392:                type = NS_ERR_UNSPEC_T, code = 0;
        !           393:                switch (error) {
        !           394: 
        !           395:                case ENETUNREACH:
        !           396:                case EHOSTDOWN:
        !           397:                case EHOSTUNREACH:
        !           398:                case ENETDOWN:
        !           399:                case EPERM:
        !           400:                        type = NS_ERR_UNREACH_HOST;
        !           401:                        break;
        !           402: 
        !           403:                case EMSGSIZE:
        !           404:                        type = NS_ERR_TOO_BIG;
        !           405:                        code = 576; /* too hard to figure out mtu here */
        !           406:                        break;
        !           407: 
        !           408:                case ENOBUFS:
        !           409:                        type = NS_ERR_UNSPEC_T;
        !           410:                        break;
        !           411:                }
        !           412:                mcopy = NULL;
        !           413:        senderror:
        !           414:                ns_error(m, type, code);
        !           415:        }
        !           416: cleanup:
        !           417:        if (ok_there)
        !           418:                idp_undo_route(&idp_droute);
        !           419:        if (ok_back)
        !           420:                idp_undo_route(&idp_sroute);
        !           421:        if (mcopy != NULL)
        !           422:                m_freem(mcopy);
        !           423: }
        !           424: 
        !           425: idp_do_route(src, ro)
        !           426: struct ns_addr *src;
        !           427: struct route *ro;
        !           428: {
        !           429:        
        !           430:        struct sockaddr_ns *dst;
        !           431: 
        !           432:        bzero((caddr_t)ro, sizeof (*ro));
        !           433:        dst = (struct sockaddr_ns *)&ro->ro_dst;
        !           434: 
        !           435:        dst->sns_len = sizeof(*dst);
        !           436:        dst->sns_family = AF_NS;
        !           437:        dst->sns_addr = *src;
        !           438:        dst->sns_addr.x_port = 0;
        !           439:        rtalloc(ro);
        !           440:        if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) {
        !           441:                return (0);
        !           442:        }
        !           443:        ro->ro_rt->rt_use++;
        !           444:        return (1);
        !           445: }
        !           446: 
        !           447: idp_undo_route(ro)
        !           448: register struct route *ro;
        !           449: {
        !           450:        if (ro->ro_rt) {RTFREE(ro->ro_rt);}
        !           451: }
        !           452: 
        !           453: ns_watch_output(m, ifp)
        !           454: struct mbuf *m;
        !           455: struct ifnet *ifp;
        !           456: {
        !           457:        register struct nspcb *nsp;
        !           458:        register struct ifaddr *ifa;
        !           459:        /*
        !           460:         * Give any raw listeners a crack at the packet
        !           461:         */
        !           462:        for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
        !           463:                struct mbuf *m0 = m_copy(m, 0, (int)M_COPYALL);
        !           464:                if (m0) {
        !           465:                        register struct idp *idp;
        !           466: 
        !           467:                        M_PREPEND(m0, sizeof (*idp), M_DONTWAIT);
        !           468:                        if (m0 == NULL)
        !           469:                                continue;
        !           470:                        idp = mtod(m0, struct idp *);
        !           471:                        idp->idp_sna.x_net = ns_zeronet;
        !           472:                        idp->idp_sna.x_host = ns_thishost;
        !           473:                        if (ifp && (ifp->if_flags & IFF_POINTOPOINT))
        !           474:                            for(ifa = ifp->if_addrlist; ifa;
        !           475:                                                ifa = ifa->ifa_next) {
        !           476:                                if (ifa->ifa_addr->sa_family==AF_NS) {
        !           477:                                    idp->idp_sna = IA_SNS(ifa)->sns_addr;
        !           478:                                    break;
        !           479:                                }
        !           480:                            }
        !           481:                        idp->idp_len = ntohl(m0->m_pkthdr.len);
        !           482:                        idp_input(m0, nsp);
        !           483:                }
        !           484:        }
        !           485: }

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