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Annotation of src/sys/netinet6/mld6.c, Revision 1.4

1.4     ! itojun      1: /*     $NetBSD: mld6.c,v 1.3 1999/07/03 21:30:19 thorpej Exp $ */
1.3       thorpej     2:
1.2       itojun      3: /*
                      4:  * Copyright (C) 1998 WIDE Project.
                      5:  * All rights reserved.
                      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. Neither the name of the project nor the names of its contributors
                     16:  *    may be used to endorse or promote products derived from this software
                     17:  *    without specific prior written permission.
                     18:  *
                     19:  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
                     20:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     21:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     22:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
                     23:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     24:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     25:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     26:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     27:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     28:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     29:  * SUCH DAMAGE.
                     30:  */
                     31:
                     32: /*
                     33:  * Copyright (c) 1988 Stephen Deering.
                     34:  * Copyright (c) 1992, 1993
                     35:  *     The Regents of the University of California.  All rights reserved.
                     36:  *
                     37:  * This code is derived from software contributed to Berkeley by
                     38:  * Stephen Deering of Stanford University.
                     39:  *
                     40:  * Redistribution and use in source and binary forms, with or without
                     41:  * modification, are permitted provided that the following conditions
                     42:  * are met:
                     43:  * 1. Redistributions of source code must retain the above copyright
                     44:  *    notice, this list of conditions and the following disclaimer.
                     45:  * 2. Redistributions in binary form must reproduce the above copyright
                     46:  *    notice, this list of conditions and the following disclaimer in the
                     47:  *    documentation and/or other materials provided with the distribution.
                     48:  * 3. All advertising materials mentioning features or use of this software
                     49:  *    must display the following acknowledgement:
                     50:  *     This product includes software developed by the University of
                     51:  *     California, Berkeley and its contributors.
                     52:  * 4. Neither the name of the University nor the names of its contributors
                     53:  *    may be used to endorse or promote products derived from this software
                     54:  *    without specific prior written permission.
                     55:  *
                     56:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     57:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     58:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     59:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     60:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     61:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     62:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     63:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     64:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     65:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     66:  * SUCH DAMAGE.
                     67:  *
                     68:  *     @(#)igmp.c      8.1 (Berkeley) 7/19/93
                     69:  */
                     70:
                     71: #if (defined(__FreeBSD__) && __FreeBSD__ >= 3) || defined(__NetBSD__)
                     72: #include "opt_inet.h"
                     73: #endif
                     74:
                     75: #include <sys/param.h>
                     76: #include <sys/systm.h>
                     77: #include <sys/mbuf.h>
                     78: #include <sys/socket.h>
                     79: #include <sys/protosw.h>
                     80: #include <sys/syslog.h>
                     81:
                     82: #include <net/if.h>
                     83:
                     84: #include <netinet/in.h>
                     85: #include <netinet/in_var.h>
                     86: #include <netinet6/in6.h>
                     87: #include <netinet6/ip6.h>
                     88: #include <netinet6/ip6_var.h>
                     89: #include <netinet6/icmp6.h>
                     90: #include <netinet6/mld6_var.h>
                     91:
                     92: /*
                     93:  * Protocol constants
                     94:  */
                     95:
                     96: /* denotes that the MLD max response delay field specifies time in milliseconds */
                     97: #define MLD6_TIMER_SCALE       1000
                     98: /*
                     99:  * time between repetitions of a node's initial report of interest in a
                    100:  * multicast address(in seconds)
                    101:  */
                    102: #define MLD6_UNSOLICITED_REPORT_INTERVAL       10
                    103:
                    104: static struct ip6_pktopts ip6_opts;
                    105: static int mld6_timers_are_running;
                    106: /* XXX: These are necessary for KAME's link-local hack */
                    107: static struct in6_addr mld6_all_nodes_linklocal = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
                    108: static struct in6_addr mld6_all_routers_linklocal = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
                    109:
                    110: static void mld6_sendpkt __P((struct in6_multi *, int, const struct in6_addr *));
                    111:
                    112: void
                    113: mld6_init()
                    114: {
                    115:        static u_int8_t hbh_buf[8];
                    116:        struct ip6_hbh *hbh = (struct ip6_hbh *)hbh_buf;
                    117:        u_int16_t rtalert_code = htons((u_int16_t)IP6OPT_RTALERT_MLD);
                    118:
                    119:        mld6_timers_are_running = 0;
                    120:
                    121:        /* ip6h_nxt will be fill in later */
                    122:        hbh->ip6h_len = 0;      /* (8 >> 3) - 1*/
                    123:
                    124:        /* XXX: grotty hard coding... */
                    125:        hbh_buf[2] = IP6OPT_PADN;       /* 2 byte padding */
                    126:        hbh_buf[3] = 0;
                    127:        hbh_buf[4] = IP6OPT_RTALERT;
                    128:        hbh_buf[5] = IP6OPT_RTALERT_LEN - 2;
                    129:        bcopy((caddr_t)&rtalert_code, &hbh_buf[6], sizeof(u_int16_t));
                    130:
                    131:        ip6_opts.ip6po_hbh = hbh;
                    132:        /* We will specify the hoplimit by a multicast option. */
                    133:        ip6_opts.ip6po_hlim = -1;
                    134: }
                    135:
                    136: void
                    137: mld6_start_listening(in6m)
                    138:        struct in6_multi *in6m;
                    139: {
1.4     ! itojun    140:        int s = splsoftnet();
1.2       itojun    141:
                    142:        /*
                    143:         * (draft-ietf-ipngwg-mld, page 10)
                    144:         * The node never sends a Report or Done for the link-scope all-nodes
                    145:         * address.
                    146:         * MLD messages are never sent for multicast addresses whose scope is 0
                    147:         * (reserved) or 1 (node-local).
                    148:         */
                    149:        mld6_all_nodes_linklocal.s6_addr16[1] =
                    150:                htons(in6m->in6m_ifp->if_index); /* XXX */
                    151:        if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal) ||
                    152:            IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) < IPV6_ADDR_SCOPE_LINKLOCAL) {
                    153:                in6m->in6m_timer = 0;
                    154:                in6m->in6m_state = MLD6_OTHERLISTENER;
                    155:        } else {
                    156:                mld6_sendpkt(in6m, MLD6_LISTENER_REPORT, NULL);
                    157:                in6m->in6m_timer = MLD6_RANDOM_DELAY(
                    158:                        MLD6_UNSOLICITED_REPORT_INTERVAL * PR_FASTHZ);
                    159:                in6m->in6m_state = MLD6_IREPORTEDLAST;
                    160:                mld6_timers_are_running = 1;
                    161:        }
                    162:        splx(s);
                    163: }
                    164:
                    165: void
                    166: mld6_stop_listening(in6m)
                    167:        struct in6_multi *in6m;
                    168: {
                    169:        mld6_all_nodes_linklocal.s6_addr16[1] =
                    170:                htons(in6m->in6m_ifp->if_index); /* XXX */
                    171:        mld6_all_routers_linklocal.s6_addr16[1] =
                    172:                htons(in6m->in6m_ifp->if_index); /* XXX: necessary when mrouting */
                    173:
                    174:        if (in6m->in6m_state == MLD6_IREPORTEDLAST &&
                    175:            (!IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr, &mld6_all_nodes_linklocal)) &&
                    176:            IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) > IPV6_ADDR_SCOPE_NODELOCAL)
                    177:                mld6_sendpkt(in6m, MLD6_LISTENER_DONE,
                    178:                             &mld6_all_routers_linklocal);
                    179: }
                    180:
                    181: void
                    182: mld6_input(m, off)
                    183:        struct mbuf *m;
                    184:        int off;
                    185: {
                    186:        struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
                    187:        struct mld6_hdr *mldh = (struct mld6_hdr *)(mtod(m, caddr_t) + off);
                    188:        struct ifnet *ifp = m->m_pkthdr.rcvif;
                    189:        struct in6_multi *in6m;
                    190:        struct in6_ifaddr *ia;
                    191:        int timer;              /* timer value in the MLD query header */
                    192:
                    193:        /* source address validation */
                    194:        if (!IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src)) {
                    195:                log(LOG_ERR,
                    196:                    "mld6_input: src %s is not link-local\n",
                    197:                    ip6_sprintf(&ip6->ip6_src));
                    198:                /*
                    199:                 * spec(draft-ietf-ipngwg-mld) does not explicitly
                    200:                 * specify to discard the packet from a non link-local
                    201:                 * source address. But we believe it's expected to do so.
                    202:                 */
                    203:                return;
                    204:        }
                    205:
                    206:        /*
                    207:         * In the MLD6 specification, there are 3 states and a flag.
                    208:         *
                    209:         * In Non-Listener state, we simply don't have a membership record.
                    210:         * In Delaying Listener state, our timer is running (in6m->in6m_timer)
                    211:         * In Idle Listener state, our timer is not running (in6m->in6m_timer==0)
                    212:         *
                    213:         * The flag is in6m->in6m_state, it is set to MLD6_OTHERLISTENER if
                    214:         * we have heard a report from another member, or MLD6_IREPORTEDLAST
                    215:         * if we sent the last report.
                    216:         */
                    217:        switch(mldh->mld6_type) {
                    218:         case MLD6_LISTENER_QUERY:
                    219:                 if (ifp->if_flags & IFF_LOOPBACK)
                    220:                         break;
                    221:
                    222:                 if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld6_addr) &&
                    223:                     !IN6_IS_ADDR_MULTICAST(&mldh->mld6_addr))
                    224:                         break; /* print error or log stat? */
                    225:                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld6_addr))
                    226:                         mldh->mld6_addr.s6_addr16[1] =
                    227:                                 htons(ifp->if_index); /* XXX */
                    228:
                    229:                /*
                    230:                 * - Start the timers in all of our membership records
                    231:                 *   that the query applies to for the interface on
                    232:                 *   which the query arrived excl. those that belong
                    233:                 *   to the "all-nodes" group (ff02::1).
                    234:                 * - Restart any timer that is already running but has
                    235:                 *   A value longer than the requested timeout.
                    236:                 * - Use the value specified in the query message as
                    237:                 *   the maximum timeout.
                    238:                 */
                    239:                 IFP_TO_IA6(ifp, ia);
                    240:                 if (ia == NULL)
                    241:                         break;
                    242:
                    243:                 /*
                    244:                  * XXX: System timer resolution is too low to handle Max
                    245:                  * Response Delay, so set 1 to the internal timer even if
                    246:                  * the calculated value equals to zero when Max Response
                    247:                  * Delay is positive.
                    248:                  */
                    249:                 timer = ntohs(mldh->mld6_maxdelay)*PR_FASTHZ/MLD6_TIMER_SCALE;
                    250:                 if (timer == 0 && mldh->mld6_maxdelay)
                    251:                         timer = 1;
                    252:                 mld6_all_nodes_linklocal.s6_addr16[1] =
                    253:                         htons(ifp->if_index); /* XXX */
                    254:
                    255:                 for (in6m = ia->ia6_multiaddrs.lh_first;
                    256:                      in6m;
                    257:                      in6m = in6m->in6m_entry.le_next) {
                    258:                         if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
                    259:                                                &mld6_all_nodes_linklocal) ||
                    260:                             IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
                    261:                             IPV6_ADDR_SCOPE_LINKLOCAL)
                    262:                             continue;
                    263:
                    264:                         if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld6_addr) ||
                    265:                             IN6_ARE_ADDR_EQUAL(&mldh->mld6_addr,
                    266:                                                &in6m->in6m_addr)) {
                    267:                                 if (timer == 0) {
                    268:                                         /* send a report immediately */
                    269:                                         mld6_sendpkt(in6m, MLD6_LISTENER_REPORT,
                    270:                                                      NULL);
                    271:                                         in6m->in6m_timer = 0; /* reset timer */
                    272:                                         in6m->in6m_state = MLD6_IREPORTEDLAST;
                    273:                                 }
                    274:                                 else if (in6m->in6m_timer == 0 || /*idle state*/
                    275:                                          in6m->in6m_timer > timer) {
                    276:                                         in6m->in6m_timer =
                    277:                                                 MLD6_RANDOM_DELAY(timer);
                    278:                                         mld6_timers_are_running = 1;
                    279:                                 }
                    280:                         }
                    281:                 }
                    282:
                    283:                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld6_addr))
                    284:                         mldh->mld6_addr.s6_addr16[1] = 0; /* XXX */
                    285:                 break;
                    286:         case MLD6_LISTENER_REPORT:
                    287:                /*
                    288:                 * For fast leave to work, we have to know that we are the
                    289:                 * last person to send a report for this group.  Reports
                    290:                 * can potentially get looped back if we are a multicast
                    291:                 * router, so discard reports sourced by me.
                    292:                 * Note that it is impossible to check IFF_LOOPBACK flag of
                    293:                 * ifp for this purpose, since ip6_mloopback pass the physical
                    294:                 * interface to looutput.
                    295:                 */
                    296:                 if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
                    297:                         break;
                    298:
                    299:                 if (!IN6_IS_ADDR_MULTICAST(&mldh->mld6_addr))
                    300:                         break;
                    301:
                    302:                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld6_addr))
                    303:                         mldh->mld6_addr.s6_addr16[1] =
                    304:                                 htons(ifp->if_index); /* XXX */
                    305:                /*
                    306:                 * If we belong to the group being reported, stop
                    307:                 * our timer for that group.
                    308:                 */
                    309:                 IN6_LOOKUP_MULTI(mldh->mld6_addr, ifp, in6m);
                    310:                 if (in6m) {
                    311:                         in6m->in6m_timer = 0; /* transit to idle state */
                    312:                         in6m->in6m_state = MLD6_OTHERLISTENER; /* clear flag */
                    313:                 }
                    314:
                    315:                 if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld6_addr))
                    316:                         mldh->mld6_addr.s6_addr16[1] = 0; /* XXX */
                    317:                 break;
                    318:         default:               /* this is impossible */
                    319:                 log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld6_type);
                    320:                 break;
                    321:        }
                    322: }
                    323:
                    324: void
                    325: mld6_fasttimeo()
                    326: {
                    327:        register struct in6_multi *in6m;
                    328:        struct in6_multistep step;
                    329:        int s;
                    330:
                    331:        /*
                    332:         * Quick check to see if any work needs to be done, in order
                    333:         * to minimize the overhead of fasttimo processing.
                    334:         */
                    335:        if (!mld6_timers_are_running)
                    336:                return;
                    337:
1.4     ! itojun    338:        s = splsoftnet();
1.2       itojun    339:        mld6_timers_are_running = 0;
                    340:        IN6_FIRST_MULTI(step, in6m);
                    341:        while (in6m != NULL) {
                    342:                if (in6m->in6m_timer == 0) {
                    343:                        /* do nothing */
                    344:                } else if (--in6m->in6m_timer == 0) {
                    345:                        mld6_sendpkt(in6m, MLD6_LISTENER_REPORT, NULL);
                    346:                        in6m->in6m_state = MLD6_IREPORTEDLAST;
                    347:                } else {
                    348:                        mld6_timers_are_running = 1;
                    349:                }
                    350:                IN6_NEXT_MULTI(step, in6m);
                    351:        }
                    352:        splx(s);
                    353: }
                    354:
                    355: static void
                    356: mld6_sendpkt(in6m, type, dst)
                    357:        struct in6_multi *in6m;
                    358:        int type;
                    359:        const struct in6_addr *dst;
                    360: {
                    361:        struct mbuf *mh, *md;
                    362:        struct mld6_hdr *mldh;
                    363:        struct ip6_hdr *ip6;
                    364:        struct ip6_moptions im6o;
                    365:        struct in6_ifaddr *ia;
                    366:        struct ifnet *ifp = in6m->in6m_ifp;
                    367:
                    368:        /*
                    369:         * At first, find a link local address on the outgoing interface
                    370:         * to use as the source address of the MLD packet.
                    371:         */
                    372:        if ((ia = in6ifa_ifpforlinklocal(ifp)) == NULL)
                    373:                return;
                    374:
                    375:        /*
                    376:         * Allocate mbufs to store ip6 header and MLD header.
                    377:         * We allocate 2 mbufs and make chain in advance because
                    378:         * it is more convenient when inserting the hop-by-hop option later.
                    379:         */
                    380:        MGETHDR(mh, M_DONTWAIT, MT_HEADER);
                    381:        if (mh == NULL)
                    382:                return;
                    383:        MGET(md, M_DONTWAIT, MT_DATA);
                    384:        if (md == NULL) {
                    385:                m_free(mh);
                    386:                return;
                    387:        }
                    388:        mh->m_next = md;
                    389:
                    390: #ifdef IPSEC
                    391:        mh->m_pkthdr.rcvif = NULL;
                    392: #endif
                    393:        mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld6_hdr);
                    394:        mh->m_len = sizeof(struct ip6_hdr);
                    395:        MH_ALIGN(mh, sizeof(struct ip6_hdr));
                    396:
                    397:        /* fill in the ip6 header */
                    398:        ip6 = mtod(mh, struct ip6_hdr *);
                    399:        ip6->ip6_flow = 0;
                    400:        ip6->ip6_vfc = IPV6_VERSION;
                    401:        /* ip6_plen will be set later */
                    402:        ip6->ip6_nxt = IPPROTO_ICMPV6;
                    403:        /* ip6_hlim will be set by im6o.im6o_multicast_hlim */
                    404:        ip6->ip6_src = ia->ia_addr.sin6_addr;
                    405:        ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;
                    406:
                    407:        /* fill in the MLD header */
                    408:        md->m_len = sizeof(struct mld6_hdr);
                    409:        mldh = mtod(md, struct mld6_hdr *);
                    410:        mldh->mld6_type = type;
                    411:        mldh->mld6_code = 0;
                    412:        mldh->mld6_cksum = 0;
                    413:        /* XXX: we assume the function will not be called for query messages */
                    414:        mldh->mld6_maxdelay = 0;
                    415:        mldh->mld6_reserved = 0;
                    416:        mldh->mld6_addr = in6m->in6m_addr;
                    417:        if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld6_addr))
                    418:                mldh->mld6_addr.s6_addr16[1] = 0; /* XXX */
                    419:        mldh->mld6_cksum = in6_cksum(mh, IPPROTO_ICMPV6, sizeof(struct ip6_hdr),
                    420:                                     sizeof(struct mld6_hdr));
                    421:
                    422:        /* construct multicast option */
                    423:        bzero(&im6o, sizeof(im6o));
                    424:        im6o.im6o_multicast_ifp = ifp;
                    425:        im6o.im6o_multicast_hlim = 1;
                    426:
                    427:        /*
                    428:         * Request loopback of the report if we are acting as a multicast
                    429:         * router, so that the process-level routing daemon can hear it.
                    430:         */
                    431:        im6o.im6o_multicast_loop = (ip6_mrouter != NULL);
                    432:
                    433:        /* increment output statictics */
                    434:        icmp6stat.icp6s_outhist[type]++;
                    435:
                    436:        ip6_output(mh, &ip6_opts, NULL, 0, &im6o);
                    437: }

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