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Annotation of XNU/bsd/netns/ns_input.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * The contents of this file constitute Original Code as defined in and
        !             7:  * are subject to the Apple Public Source License Version 1.1 (the
        !             8:  * "License").  You may not use this file except in compliance with the
        !             9:  * License.  Please obtain a copy of the License at
        !            10:  * http://www.apple.com/publicsource and read it before using this file.
        !            11:  * 
        !            12:  * This Original Code and all software distributed under the License are
        !            13:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            14:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            15:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            16:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            17:  * License for the specific language governing rights and limitations
        !            18:  * under the License.
        !            19:  * 
        !            20:  * @APPLE_LICENSE_HEADER_END@
        !            21:  */
        !            22: /*
        !            23:  * Copyright (c) 1984, 1985, 1986, 1987, 1993
        !            24:  *     The Regents of the University of California.  All rights reserved.
        !            25:  *
        !            26:  * Redistribution and use in source and binary forms, with or without
        !            27:  * modification, are permitted provided that the following conditions
        !            28:  * are met:
        !            29:  * 1. Redistributions of source code must retain the above copyright
        !            30:  *    notice, this list of conditions and the following disclaimer.
        !            31:  * 2. Redistributions in binary form must reproduce the above copyright
        !            32:  *    notice, this list of conditions and the following disclaimer in the
        !            33:  *    documentation and/or other materials provided with the distribution.
        !            34:  * 3. All advertising materials mentioning features or use of this software
        !            35:  *    must display the following acknowledgement:
        !            36:  *     This product includes software developed by the University of
        !            37:  *     California, Berkeley and its contributors.
        !            38:  * 4. Neither the name of the University nor the names of its contributors
        !            39:  *    may be used to endorse or promote products derived from this software
        !            40:  *    without specific prior written permission.
        !            41:  *
        !            42:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            43:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            44:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            45:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            46:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            47:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            48:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            49:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            50:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            51:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            52:  * SUCH DAMAGE.
        !            53:  *
        !            54:  *     @(#)ns_input.c  8.1 (Berkeley) 6/10/93
        !            55:  */
        !            56: 
        !            57: #include <sys/param.h>
        !            58: #include <sys/systm.h>
        !            59: #include <sys/malloc.h>
        !            60: #include <sys/mbuf.h>
        !            61: #include <sys/domain.h>
        !            62: #include <sys/protosw.h>
        !            63: #include <sys/socket.h>
        !            64: #include <sys/socketvar.h>
        !            65: #include <sys/errno.h>
        !            66: #include <sys/time.h>
        !            67: #include <sys/kernel.h>
        !            68: 
        !            69: #include <net/if.h>
        !            70: #include <net/route.h>
        !            71: #include <net/raw_cb.h>
        !            72: 
        !            73: #include <netns/ns.h>
        !            74: #include <netns/ns_if.h>
        !            75: #include <netns/ns_pcb.h>
        !            76: #include <netns/idp.h>
        !            77: #include <netns/idp_var.h>
        !            78: #include <netns/ns_error.h>
        !            79: 
        !            80: /*
        !            81:  * NS initialization.
        !            82:  */
        !            83: union ns_host  ns_thishost;
        !            84: union ns_host  ns_zerohost;
        !            85: union ns_host  ns_broadhost;
        !            86: union ns_net   ns_zeronet;
        !            87: union ns_net   ns_broadnet;
        !            88: struct sockaddr_ns ns_netmask, ns_hostmask;
        !            89: 
        !            90: static u_short allones[] = {-1, -1, -1};
        !            91: 
        !            92: struct nspcb nspcb;
        !            93: struct nspcb nsrawpcb;
        !            94: 
        !            95: struct ifqueue nsintrq;
        !            96: int    nsqmaxlen = IFQ_MAXLEN;
        !            97: 
        !            98: int    idpcksum = 1;
        !            99: long   ns_pexseq;
        !           100: 
        !           101: ns_init()
        !           102: {
        !           103:        extern struct timeval time;
        !           104: 
        !           105:        ns_broadhost = * (union ns_host *) allones;
        !           106:        ns_broadnet = * (union ns_net *) allones;
        !           107:        nspcb.nsp_next = nspcb.nsp_prev = &nspcb;
        !           108:        nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb;
        !           109:        nsintrq.ifq_maxlen = nsqmaxlen;
        !           110:        ns_pexseq = time.tv_usec;
        !           111:        ns_netmask.sns_len = 6;
        !           112:        ns_netmask.sns_addr.x_net = ns_broadnet;
        !           113:        ns_hostmask.sns_len = 12;
        !           114:        ns_hostmask.sns_addr.x_net = ns_broadnet;
        !           115:        ns_hostmask.sns_addr.x_host = ns_broadhost;
        !           116: }
        !           117: 
        !           118: /*
        !           119:  * Idp input routine.  Pass to next level.
        !           120:  */
        !           121: int nsintr_getpck = 0;
        !           122: int nsintr_swtch = 0;
        !           123: nsintr()
        !           124: {
        !           125:        register struct idp *idp;
        !           126:        register struct mbuf *m;
        !           127:        register struct nspcb *nsp;
        !           128:        register int i;
        !           129:        int len, s, error;
        !           130:        char oddpacketp;
        !           131: 
        !           132: next:
        !           133:        /*
        !           134:         * Get next datagram off input queue and get IDP header
        !           135:         * in first mbuf.
        !           136:         */
        !           137:        s = splimp();
        !           138:        IF_DEQUEUE(&nsintrq, m);
        !           139:        splx(s);
        !           140:        nsintr_getpck++;
        !           141:        if (m == 0)
        !           142:                return;
        !           143:        if ((m->m_flags & M_EXT || m->m_len < sizeof (struct idp)) &&
        !           144:            (m = m_pullup(m, sizeof (struct idp))) == 0) {
        !           145:                idpstat.idps_toosmall++;
        !           146:                goto next;
        !           147:        }
        !           148: 
        !           149:        /*
        !           150:         * Give any raw listeners a crack at the packet
        !           151:         */
        !           152:        for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
        !           153:                struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
        !           154:                if (m1) idp_input(m1, nsp);
        !           155:        }
        !           156: 
        !           157:        idp = mtod(m, struct idp *);
        !           158:        len = ntohs(idp->idp_len);
        !           159:        if (oddpacketp = len & 1) {
        !           160:                len++;          /* If this packet is of odd length,
        !           161:                                   preserve garbage byte for checksum */
        !           162:        }
        !           163: 
        !           164:        /*
        !           165:         * Check that the amount of data in the buffers
        !           166:         * is as at least much as the IDP header would have us expect.
        !           167:         * Trim mbufs if longer than we expect.
        !           168:         * Drop packet if shorter than we expect.
        !           169:         */
        !           170:        if (m->m_pkthdr.len < len) {
        !           171:                idpstat.idps_tooshort++;
        !           172:                goto bad;
        !           173:        }
        !           174:        if (m->m_pkthdr.len > len) {
        !           175:                if (m->m_len == m->m_pkthdr.len) {
        !           176:                        m->m_len = len;
        !           177:                        m->m_pkthdr.len = len;
        !           178:                } else
        !           179:                        m_adj(m, len - m->m_pkthdr.len);
        !           180:        }
        !           181:        if (idpcksum && ((i = idp->idp_sum)!=0xffff)) {
        !           182:                idp->idp_sum = 0;
        !           183:                if (i != (idp->idp_sum = ns_cksum(m, len))) {
        !           184:                        idpstat.idps_badsum++;
        !           185:                        idp->idp_sum = i;
        !           186:                        if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host))
        !           187:                                error = NS_ERR_BADSUM;
        !           188:                        else
        !           189:                                error = NS_ERR_BADSUM_T;
        !           190:                        ns_error(m, error, 0);
        !           191:                        goto next;
        !           192:                }
        !           193:        }
        !           194:        /*
        !           195:         * Is this a directed broadcast?
        !           196:         */
        !           197:        if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) {
        !           198:                if ((!ns_neteq(idp->idp_dna, idp->idp_sna)) &&
        !           199:                    (!ns_neteqnn(idp->idp_dna.x_net, ns_broadnet)) &&
        !           200:                    (!ns_neteqnn(idp->idp_sna.x_net, ns_zeronet)) &&
        !           201:                    (!ns_neteqnn(idp->idp_dna.x_net, ns_zeronet)) ) {
        !           202:                        /*
        !           203:                         * Look to see if I need to eat this packet.
        !           204:                         * Algorithm is to forward all young packets
        !           205:                         * and prematurely age any packets which will
        !           206:                         * by physically broadcasted.
        !           207:                         * Any very old packets eaten without forwarding
        !           208:                         * would die anyway.
        !           209:                         *
        !           210:                         * Suggestion of Bill Nesheim, Cornell U.
        !           211:                         */
        !           212:                        if (idp->idp_tc < NS_MAXHOPS) {
        !           213:                                idp_forward(m);
        !           214:                                goto next;
        !           215:                        }
        !           216:                }
        !           217:        /*
        !           218:         * Is this our packet? If not, forward.
        !           219:         */
        !           220:        } else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) {
        !           221:                idp_forward(m);
        !           222:                goto next;
        !           223:        }
        !           224:        /*
        !           225:         * Locate pcb for datagram.
        !           226:         */
        !           227:        nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD);
        !           228:        /*
        !           229:         * Switch out to protocol's input routine.
        !           230:         */
        !           231:        nsintr_swtch++;
        !           232:        if (nsp) {
        !           233:                if (oddpacketp) {
        !           234:                        m_adj(m, -1);
        !           235:                }
        !           236:                if ((nsp->nsp_flags & NSP_ALL_PACKETS)==0)
        !           237:                        switch (idp->idp_pt) {
        !           238: 
        !           239:                            case NSPROTO_SPP:
        !           240:                                    spp_input(m, nsp);
        !           241:                                    goto next;
        !           242: 
        !           243:                            case NSPROTO_ERROR:
        !           244:                                    ns_err_input(m);
        !           245:                                    goto next;
        !           246:                        }
        !           247:                idp_input(m, nsp);
        !           248:        } else {
        !           249:                ns_error(m, NS_ERR_NOSOCK, 0);
        !           250:        }
        !           251:        goto next;
        !           252: 
        !           253: bad:
        !           254:        m_freem(m);
        !           255:        goto next;
        !           256: }
        !           257: 
        !           258: u_char nsctlerrmap[PRC_NCMDS] = {
        !           259:        ECONNABORTED,   ECONNABORTED,   0,              0,
        !           260:        0,              0,              EHOSTDOWN,      EHOSTUNREACH,
        !           261:        ENETUNREACH,    EHOSTUNREACH,   ECONNREFUSED,   ECONNREFUSED,
        !           262:        EMSGSIZE,       0,              0,              0,
        !           263:        0,              0,              0,              0
        !           264: };
        !           265: 
        !           266: int idp_donosocks = 1;
        !           267: 
        !           268: idp_ctlinput(cmd, arg)
        !           269:        int cmd;
        !           270:        caddr_t arg;
        !           271: {
        !           272:        struct ns_addr *ns;
        !           273:        struct nspcb *nsp;
        !           274:        struct ns_errp *errp;
        !           275:        int idp_abort();
        !           276:        extern struct nspcb *idp_drop();
        !           277:        int type;
        !           278: 
        !           279:        if (cmd < 0 || cmd > PRC_NCMDS)
        !           280:                return;
        !           281:        if (nsctlerrmap[cmd] == 0)
        !           282:                return;         /* XXX */
        !           283:        type = NS_ERR_UNREACH_HOST;
        !           284:        switch (cmd) {
        !           285:                struct sockaddr_ns *sns;
        !           286: 
        !           287:        case PRC_IFDOWN:
        !           288:        case PRC_HOSTDEAD:
        !           289:        case PRC_HOSTUNREACH:
        !           290:                sns = (struct sockaddr_ns *)arg;
        !           291:                if (sns->sns_family != AF_NS)
        !           292:                        return;
        !           293:                ns = &sns->sns_addr;
        !           294:                break;
        !           295: 
        !           296:        default:
        !           297:                errp = (struct ns_errp *)arg;
        !           298:                ns = &errp->ns_err_idp.idp_dna;
        !           299:                type = errp->ns_err_num;
        !           300:                type = ntohs((u_short)type);
        !           301:        }
        !           302:        switch (type) {
        !           303: 
        !           304:        case NS_ERR_UNREACH_HOST:
        !           305:                ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, (long)0);
        !           306:                break;
        !           307: 
        !           308:        case NS_ERR_NOSOCK:
        !           309:                nsp = ns_pcblookup(ns, errp->ns_err_idp.idp_sna.x_port,
        !           310:                        NS_WILDCARD);
        !           311:                if(nsp && idp_donosocks && ! ns_nullhost(nsp->nsp_faddr))
        !           312:                        (void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
        !           313:        }
        !           314: }
        !           315: 
        !           316: int    idpprintfs = 0;
        !           317: int    idpforwarding = 1;
        !           318: /*
        !           319:  * Forward a packet.  If some error occurs return the sender
        !           320:  * an error packet.  Note we can't always generate a meaningful
        !           321:  * error message because the NS errors don't have a large enough repetoire
        !           322:  * of codes and types.
        !           323:  */
        !           324: struct route idp_droute;
        !           325: struct route idp_sroute;
        !           326: 
        !           327: idp_forward(m)
        !           328: struct mbuf *m;
        !           329: {
        !           330:        register struct idp *idp = mtod(m, struct idp *);
        !           331:        register int error, type, code;
        !           332:        struct mbuf *mcopy = NULL;
        !           333:        int agedelta = 1;
        !           334:        int flags = NS_FORWARDING;
        !           335:        int ok_there = 0;
        !           336:        int ok_back = 0;
        !           337: 
        !           338:        if (idpprintfs) {
        !           339:                printf("forward: src ");
        !           340:                ns_printhost(&idp->idp_sna);
        !           341:                printf(", dst ");
        !           342:                ns_printhost(&idp->idp_dna);
        !           343:                printf("hop count %d\n", idp->idp_tc);
        !           344:        }
        !           345:        if (idpforwarding == 0) {
        !           346:                /* can't tell difference between net and host */
        !           347:                type = NS_ERR_UNREACH_HOST, code = 0;
        !           348:                goto senderror;
        !           349:        }
        !           350:        idp->idp_tc++;
        !           351:        if (idp->idp_tc > NS_MAXHOPS) {
        !           352:                type = NS_ERR_TOO_OLD, code = 0;
        !           353:                goto senderror;
        !           354:        }
        !           355:        /*
        !           356:         * Save at most 42 bytes of the packet in case
        !           357:         * we need to generate an NS error message to the src.
        !           358:         */
        !           359:        mcopy = m_copy(m, 0, imin((int)ntohs(idp->idp_len), 42));
        !           360: 
        !           361:        if ((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) {
        !           362:                type = NS_ERR_UNREACH_HOST, code = 0;
        !           363:                goto senderror;
        !           364:        }
        !           365:        /*
        !           366:         * Here we think about  forwarding  broadcast packets,
        !           367:         * so we try to insure that it doesn't go back out
        !           368:         * on the interface it came in on.  Also, if we
        !           369:         * are going to physically broadcast this, let us
        !           370:         * age the packet so we can eat it safely the second time around.
        !           371:         */
        !           372:        if (idp->idp_dna.x_host.c_host[0] & 0x1) {
        !           373:                struct ns_ifaddr *ia = ns_iaonnetof(&idp->idp_dna);
        !           374:                struct ifnet *ifp;
        !           375:                if (ia) {
        !           376:                        /* I'm gonna hafta eat this packet */
        !           377:                        agedelta += NS_MAXHOPS - idp->idp_tc;
        !           378:                        idp->idp_tc = NS_MAXHOPS;
        !           379:                }
        !           380:                if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) {
        !           381:                        /* error = ENETUNREACH; He'll never get it! */
        !           382:                        m_freem(m);
        !           383:                        goto cleanup;
        !           384:                }
        !           385:                if (idp_droute.ro_rt &&
        !           386:                    (ifp=idp_droute.ro_rt->rt_ifp) &&
        !           387:                    idp_sroute.ro_rt &&
        !           388:                    (ifp!=idp_sroute.ro_rt->rt_ifp)) {
        !           389:                        flags |= NS_ALLOWBROADCAST;
        !           390:                } else {
        !           391:                        type = NS_ERR_UNREACH_HOST, code = 0;
        !           392:                        goto senderror;
        !           393:                }
        !           394:        }
        !           395:        /* need to adjust checksum */
        !           396:        if (idp->idp_sum!=0xffff) {
        !           397:                union bytes {
        !           398:                        u_char c[4];
        !           399:                        u_short s[2];
        !           400:                        long l;
        !           401:                } x;
        !           402:                register int shift;
        !           403:                x.l = 0; x.c[0] = agedelta;
        !           404:                shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf;
        !           405:                x.l = idp->idp_sum + (x.s[0] << shift);
        !           406:                x.l = x.s[0] + x.s[1];
        !           407:                x.l = x.s[0] + x.s[1];
        !           408:                if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l;
        !           409:        }
        !           410:        if ((error = ns_output(m, &idp_droute, flags)) && 
        !           411:            (mcopy!=NULL)) {
        !           412:                idp = mtod(mcopy, struct idp *);
        !           413:                type = NS_ERR_UNSPEC_T, code = 0;
        !           414:                switch (error) {
        !           415: 
        !           416:                case ENETUNREACH:
        !           417:                case EHOSTDOWN:
        !           418:                case EHOSTUNREACH:
        !           419:                case ENETDOWN:
        !           420:                case EPERM:
        !           421:                        type = NS_ERR_UNREACH_HOST;
        !           422:                        break;
        !           423: 
        !           424:                case EMSGSIZE:
        !           425:                        type = NS_ERR_TOO_BIG;
        !           426:                        code = 576; /* too hard to figure out mtu here */
        !           427:                        break;
        !           428: 
        !           429:                case ENOBUFS:
        !           430:                        type = NS_ERR_UNSPEC_T;
        !           431:                        break;
        !           432:                }
        !           433:                mcopy = NULL;
        !           434:        senderror:
        !           435:                ns_error(m, type, code);
        !           436:        }
        !           437: cleanup:
        !           438:        if (ok_there)
        !           439:                idp_undo_route(&idp_droute);
        !           440:        if (ok_back)
        !           441:                idp_undo_route(&idp_sroute);
        !           442:        if (mcopy != NULL)
        !           443:                m_freem(mcopy);
        !           444: }
        !           445: 
        !           446: idp_do_route(src, ro)
        !           447: struct ns_addr *src;
        !           448: struct route *ro;
        !           449: {
        !           450:        
        !           451:        struct sockaddr_ns *dst;
        !           452: 
        !           453:        bzero((caddr_t)ro, sizeof (*ro));
        !           454:        dst = (struct sockaddr_ns *)&ro->ro_dst;
        !           455: 
        !           456:        dst->sns_len = sizeof(*dst);
        !           457:        dst->sns_family = AF_NS;
        !           458:        dst->sns_addr = *src;
        !           459:        dst->sns_addr.x_port = 0;
        !           460:        rtalloc(ro);
        !           461:        if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) {
        !           462:                return (0);
        !           463:        }
        !           464:        ro->ro_rt->rt_use++;
        !           465:        return (1);
        !           466: }
        !           467: 
        !           468: idp_undo_route(ro)
        !           469: register struct route *ro;
        !           470: {
        !           471:        if (ro->ro_rt) {RTFREE(ro->ro_rt);}
        !           472: }
        !           473: 
        !           474: ns_watch_output(m, ifp)
        !           475: struct mbuf *m;
        !           476: struct ifnet *ifp;
        !           477: {
        !           478:        register struct nspcb *nsp;
        !           479:        register struct ifaddr *ifa;
        !           480:        /*
        !           481:         * Give any raw listeners a crack at the packet
        !           482:         */
        !           483:        for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
        !           484:                struct mbuf *m0 = m_copy(m, 0, (int)M_COPYALL);
        !           485:                if (m0) {
        !           486:                        register struct idp *idp;
        !           487: 
        !           488:                        M_PREPEND(m0, sizeof (*idp), M_DONTWAIT);
        !           489:                        if (m0 == NULL)
        !           490:                                continue;
        !           491:                        idp = mtod(m0, struct idp *);
        !           492:                        idp->idp_sna.x_net = ns_zeronet;
        !           493:                        idp->idp_sna.x_host = ns_thishost;
        !           494:                        if (ifp && (ifp->if_flags & IFF_POINTOPOINT))
        !           495:                            for(ifa = ifp->if_addrlist; ifa;
        !           496:                                                ifa = ifa->ifa_next) {
        !           497:                                if (ifa->ifa_addr->sa_family==AF_NS) {
        !           498:                                    idp->idp_sna = IA_SNS(ifa)->sns_addr;
        !           499:                                    break;
        !           500:                                }
        !           501:                            }
        !           502:                        idp->idp_len = ntohl(m0->m_pkthdr.len);
        !           503:                        idp_input(m0, nsp);
        !           504:                }
        !           505:        }
        !           506: }

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