diff options
Diffstat (limited to 'c/src/libnetworking/netinet/igmp.c')
-rw-r--r-- | c/src/libnetworking/netinet/igmp.c | 479 |
1 files changed, 479 insertions, 0 deletions
diff --git a/c/src/libnetworking/netinet/igmp.c b/c/src/libnetworking/netinet/igmp.c new file mode 100644 index 0000000000..2af8b7038e --- /dev/null +++ b/c/src/libnetworking/netinet/igmp.c @@ -0,0 +1,479 @@ +/* + * Copyright (c) 1988 Stephen Deering. + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Stephen Deering of Stanford University. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)igmp.c 8.1 (Berkeley) 7/19/93 + * $Id$ + */ + +/* + * Internet Group Management Protocol (IGMP) routines. + * + * Written by Steve Deering, Stanford, May 1988. + * Modified by Rosen Sharma, Stanford, Aug 1994. + * Modified by Bill Fenner, Xerox PARC, Feb 1995. + * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995. + * + * MULTICAST Revision: 3.5.1.4 + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/mbuf.h> +#include <sys/socket.h> +#include <sys/protosw.h> +#include <sys/kernel.h> +#include <sys/sysctl.h> + +#include <net/if.h> +#include <net/route.h> + +#include <netinet/in.h> +#include <netinet/in_var.h> +#include <netinet/in_systm.h> +#include <netinet/ip.h> +#include <netinet/ip_var.h> +#include <netinet/igmp.h> +#include <netinet/igmp_var.h> + +static struct router_info * + find_rti __P((struct ifnet *ifp)); + +static struct igmpstat igmpstat; + +SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RD, + &igmpstat, igmpstat, ""); + +static int igmp_timers_are_running; +static u_long igmp_all_hosts_group; +static u_long igmp_all_rtrs_group; +static struct mbuf *router_alert; +static struct router_info *Head; + +static void igmp_sendpkt(struct in_multi *, int, unsigned long); + +void +igmp_init() +{ + struct ipoption *ra; + + /* + * To avoid byte-swapping the same value over and over again. + */ + igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP); + igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP); + + igmp_timers_are_running = 0; + + /* + * Construct a Router Alert option to use in outgoing packets + */ + MGET(router_alert, M_DONTWAIT, MT_DATA); + ra = mtod(router_alert, struct ipoption *); + ra->ipopt_dst.s_addr = 0; + ra->ipopt_list[0] = IPOPT_RA; /* Router Alert Option */ + ra->ipopt_list[1] = 0x04; /* 4 bytes long */ + ra->ipopt_list[2] = 0x00; + ra->ipopt_list[3] = 0x00; + router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1]; + + Head = (struct router_info *) 0; +} + +static struct router_info * +find_rti(ifp) + struct ifnet *ifp; +{ + register struct router_info *rti = Head; + +#ifdef IGMP_DEBUG + printf("[igmp.c, _find_rti] --> entering \n"); +#endif + while (rti) { + if (rti->rti_ifp == ifp) { +#ifdef IGMP_DEBUG + printf("[igmp.c, _find_rti] --> found old entry \n"); +#endif + return rti; + } + rti = rti->rti_next; + } + MALLOC(rti, struct router_info *, sizeof *rti, M_MRTABLE, M_NOWAIT); + rti->rti_ifp = ifp; + rti->rti_type = IGMP_V2_ROUTER; + rti->rti_time = 0; + rti->rti_next = Head; + Head = rti; +#ifdef IGMP_DEBUG + printf("[igmp.c, _find_rti] --> created an entry \n"); +#endif + return rti; +} + +void +igmp_input(m, iphlen) + register struct mbuf *m; + register int iphlen; +{ + register struct igmp *igmp; + register struct ip *ip; + register int igmplen; + register struct ifnet *ifp = m->m_pkthdr.rcvif; + register int minlen; + register struct in_multi *inm; + register struct in_ifaddr *ia; + struct in_multistep step; + struct router_info *rti; + + int timer; /** timer value in the igmp query header **/ + + ++igmpstat.igps_rcv_total; + + ip = mtod(m, struct ip *); + igmplen = ip->ip_len; + + /* + * Validate lengths + */ + if (igmplen < IGMP_MINLEN) { + ++igmpstat.igps_rcv_tooshort; + m_freem(m); + return; + } + minlen = iphlen + IGMP_MINLEN; + if ((m->m_flags & M_EXT || m->m_len < minlen) && + (m = m_pullup(m, minlen)) == 0) { + ++igmpstat.igps_rcv_tooshort; + return; + } + + /* + * Validate checksum + */ + m->m_data += iphlen; + m->m_len -= iphlen; + igmp = mtod(m, struct igmp *); + if (in_cksum(m, igmplen)) { + ++igmpstat.igps_rcv_badsum; + m_freem(m); + return; + } + m->m_data -= iphlen; + m->m_len += iphlen; + + ip = mtod(m, struct ip *); + timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE; + rti = find_rti(ifp); + + /* + * In the IGMPv2 specification, there are 3 states and a flag. + * + * In Non-Member state, we simply don't have a membership record. + * In Delaying Member state, our timer is running (inm->inm_timer) + * In Idle Member state, our timer is not running (inm->inm_timer==0) + * + * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if + * we have heard a report from another member, or IGMP_IREPORTEDLAST + * if I sent the last report. + */ + switch (igmp->igmp_type) { + + case IGMP_MEMBERSHIP_QUERY: + ++igmpstat.igps_rcv_queries; + + if (ifp->if_flags & IFF_LOOPBACK) + break; + + if (igmp->igmp_code == 0) { + /* + * Old router. Remember that the querier on this + * interface is old, and set the timer to the + * value in RFC 1112. + */ + + rti->rti_type = IGMP_V1_ROUTER; + rti->rti_time = 0; + + timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ; + + if (ip->ip_dst.s_addr != igmp_all_hosts_group || + igmp->igmp_group.s_addr != 0) { + ++igmpstat.igps_rcv_badqueries; + m_freem(m); + return; + } + } else { + /* + * New router. Simply do the new validity check. + */ + + if (igmp->igmp_group.s_addr != 0 && + !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { + ++igmpstat.igps_rcv_badqueries; + m_freem(m); + return; + } + } + + /* + * - Start the timers in all of our membership records + * that the query applies to for the interface on + * which the query arrived excl. those that belong + * to the "all-hosts" group (224.0.0.1). + * - Restart any timer that is already running but has + * a value longer than the requested timeout. + * - Use the value specified in the query message as + * the maximum timeout. + */ + IN_FIRST_MULTI(step, inm); + while (inm != NULL) { + if (inm->inm_ifp == ifp && + inm->inm_addr.s_addr != igmp_all_hosts_group && + (igmp->igmp_group.s_addr == 0 || + igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) { + if (inm->inm_timer == 0 || + inm->inm_timer > timer) { + inm->inm_timer = + IGMP_RANDOM_DELAY(timer); + igmp_timers_are_running = 1; + } + } + IN_NEXT_MULTI(step, inm); + } + + break; + + case IGMP_V1_MEMBERSHIP_REPORT: + case IGMP_V2_MEMBERSHIP_REPORT: + /* + * For fast leave to work, we have to know that we are the + * last person to send a report for this group. Reports + * can potentially get looped back if we are a multicast + * router, so discard reports sourced by me. + */ + IFP_TO_IA(ifp, ia); + if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr) + break; + + ++igmpstat.igps_rcv_reports; + + if (ifp->if_flags & IFF_LOOPBACK) + break; + + if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) { + ++igmpstat.igps_rcv_badreports; + m_freem(m); + return; + } + + /* + * KLUDGE: if the IP source address of the report has an + * unspecified (i.e., zero) subnet number, as is allowed for + * a booting host, replace it with the correct subnet number + * so that a process-level multicast routing demon can + * determine which subnet it arrived from. This is necessary + * to compensate for the lack of any way for a process to + * determine the arrival interface of an incoming packet. + */ + if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) + if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet); + + /* + * If we belong to the group being reported, stop + * our timer for that group. + */ + IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm); + + if (inm != NULL) { + inm->inm_timer = 0; + ++igmpstat.igps_rcv_ourreports; + + inm->inm_state = IGMP_OTHERMEMBER; + } + + break; + } + + /* + * Pass all valid IGMP packets up to any process(es) listening + * on a raw IGMP socket. + */ + rip_input(m, iphlen); +} + +void +igmp_joingroup(inm) + struct in_multi *inm; +{ + int s = splnet(); + + if (inm->inm_addr.s_addr == igmp_all_hosts_group + || inm->inm_ifp->if_flags & IFF_LOOPBACK) { + inm->inm_timer = 0; + inm->inm_state = IGMP_OTHERMEMBER; + } else { + inm->inm_rti = find_rti(inm->inm_ifp); + igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); + inm->inm_timer = IGMP_RANDOM_DELAY( + IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ); + inm->inm_state = IGMP_IREPORTEDLAST; + igmp_timers_are_running = 1; + } + splx(s); +} + +void +igmp_leavegroup(inm) + struct in_multi *inm; +{ + if (inm->inm_state == IGMP_IREPORTEDLAST && + inm->inm_addr.s_addr != igmp_all_hosts_group && + !(inm->inm_ifp->if_flags & IFF_LOOPBACK) && + inm->inm_rti->rti_type != IGMP_V1_ROUTER) + igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group); +} + +void +igmp_fasttimo() +{ + register struct in_multi *inm; + struct in_multistep step; + int s; + + /* + * Quick check to see if any work needs to be done, in order + * to minimize the overhead of fasttimo processing. + */ + + if (!igmp_timers_are_running) + return; + + s = splnet(); + igmp_timers_are_running = 0; + IN_FIRST_MULTI(step, inm); + while (inm != NULL) { + if (inm->inm_timer == 0) { + /* do nothing */ + } else if (--inm->inm_timer == 0) { + igmp_sendpkt(inm, inm->inm_rti->rti_type, 0); + inm->inm_state = IGMP_IREPORTEDLAST; + } else { + igmp_timers_are_running = 1; + } + IN_NEXT_MULTI(step, inm); + } + splx(s); +} + +void +igmp_slowtimo() +{ + int s = splnet(); + register struct router_info *rti = Head; + +#ifdef IGMP_DEBUG + printf("[igmp.c,_slowtimo] -- > entering \n"); +#endif + while (rti) { + if (rti->rti_type == IGMP_V1_ROUTER) { + rti->rti_time++; + if (rti->rti_time >= IGMP_AGE_THRESHOLD) { + rti->rti_type = IGMP_V2_ROUTER; + } + } + rti = rti->rti_next; + } +#ifdef IGMP_DEBUG + printf("[igmp.c,_slowtimo] -- > exiting \n"); +#endif + splx(s); +} + +static struct route igmprt; + +static void +igmp_sendpkt(inm, type, addr) + struct in_multi *inm; + int type; + unsigned long addr; +{ + struct mbuf *m; + struct igmp *igmp; + struct ip *ip; + struct ip_moptions imo; + + MGETHDR(m, M_DONTWAIT, MT_HEADER); + if (m == NULL) + return; + + m->m_pkthdr.rcvif = loif; + m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN; + MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip)); + m->m_data += sizeof(struct ip); + m->m_len = IGMP_MINLEN; + igmp = mtod(m, struct igmp *); + igmp->igmp_type = type; + igmp->igmp_code = 0; + igmp->igmp_group = inm->inm_addr; + igmp->igmp_cksum = 0; + igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN); + + m->m_data -= sizeof(struct ip); + m->m_len += sizeof(struct ip); + ip = mtod(m, struct ip *); + ip->ip_tos = 0; + ip->ip_len = sizeof(struct ip) + IGMP_MINLEN; + ip->ip_off = 0; + ip->ip_p = IPPROTO_IGMP; + ip->ip_src.s_addr = INADDR_ANY; + ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr; + + imo.imo_multicast_ifp = inm->inm_ifp; + imo.imo_multicast_ttl = 1; + imo.imo_multicast_vif = -1; + /* + * Request loopback of the report if we are acting as a multicast + * router, so that the process-level routing demon can hear it. + */ + imo.imo_multicast_loop = (ip_mrouter != NULL); + + /* + * XXX + * Do we have to worry about reentrancy here? Don't think so. + */ + ip_output(m, router_alert, &igmprt, 0, &imo); + + ++igmpstat.igps_snd_reports; +} |