[unix-history] / usr / src / sys / netinet / igmp.c

/*
 * Copyright (c) 1988 Stephen Deering.
 * Copyright (c) 1992 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Stephen Deering of Stanford University.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)igmp.c	8.1 (Berkeley) %G%
 */

/* Internet Group Management Protocol (IGMP) routines. */


#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/protosw.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>

extern struct ifnet loif;

static int igmp_timers_are_running = 0;
static u_long igmp_all_hosts_group;

static void igmp_sendreport __P((struct in_multi *));

void
igmp_init()
{
	/*
	 * To avoid byte-swapping the same value over and over again.
	 */
	igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
}

void
igmp_input(m, ifp)
	register struct mbuf *m;
	register struct ifnet *ifp;
{
	register struct igmp *igmp;
	register struct ip *ip;
	register int igmplen;
	register int iphlen;
	register int minlen;
	register struct in_multi *inm;
	register struct in_ifaddr *ia;
	struct in_multistep step;

	++igmpstat.igps_rcv_total;

	ip = mtod(m, struct ip *);
	iphlen = ip->ip_hl << 2;
	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 *);

	switch (igmp->igmp_type) {

	case IGMP_HOST_MEMBERSHIP_QUERY:
		++igmpstat.igps_rcv_queries;

		if (ifp == &loif)
			break;

		if (ip->ip_dst.s_addr != igmp_all_hosts_group) {
			++igmpstat.igps_rcv_badqueries;
			m_freem(m);
			return;
		}

		/*
		 * Start the timers in all of our membership records for
		 * the interface on which the query arrived, except those
		 * that are already running and those that belong to the
		 * "all-hosts" group.
		 */
		IN_FIRST_MULTI(step, inm);
		while (inm != NULL) {
			if (inm->inm_ifp == ifp && inm->inm_timer == 0 &&
			    inm->inm_addr.s_addr != igmp_all_hosts_group) {
				inm->inm_timer =
				    IGMP_RANDOM_DELAY(inm->inm_addr);
				igmp_timers_are_running = 1;
			}
			IN_NEXT_MULTI(step, inm);
		}

		break;

	case IGMP_HOST_MEMBERSHIP_REPORT:
		++igmpstat.igps_rcv_reports;

		if (ifp == &loif)
			break;

		if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr)) ||
		    igmp->igmp_group.s_addr != ip->ip_dst.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) {
			IFP_TO_IA(ifp, ia);
			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;
		}

		break;
	}

	/*
	 * Pass all valid IGMP packets up to any process(es) listening
	 * on a raw IGMP socket.
	 */
	rip_input(m);
}

void
igmp_joingroup(inm)
	struct in_multi *inm;
{
	register int s = splnet();

	if (inm->inm_addr.s_addr == igmp_all_hosts_group ||
	    inm->inm_ifp == &loif)
		inm->inm_timer = 0;
	else {
		igmp_sendreport(inm);
		inm->inm_timer = IGMP_RANDOM_DELAY(inm->inm_addr);
		igmp_timers_are_running = 1;
	}
	splx(s);
}

void
igmp_leavegroup(inm)
	struct in_multi *inm;
{
	/*
	 * No action required on leaving a group.
	 */
}

void
igmp_fasttimo()
{
	register struct in_multi *inm;
	register int s;
	struct in_multistep step;

	/*
	 * 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_sendreport(inm);
		} else {
			igmp_timers_are_running = 1;
		}
		IN_NEXT_MULTI(step, inm);
	}
	splx(s);
}

static void
igmp_sendreport(inm)
	register struct in_multi *inm;
{
	register struct mbuf *m;
	register struct igmp *igmp;
	register struct ip *ip;
	register struct ip_moptions *imo;
	struct ip_moptions simo;

	MGETHDR(m, M_DONTWAIT, MT_HEADER);
	if (m == NULL)
		return;
	m->m_data += max_linkhdr;
	m->m_len = sizeof(struct ip) + IGMP_MINLEN;

	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 = inm->inm_addr;

	igmp = (struct igmp *)(ip + 1);
	igmp->igmp_type = IGMP_HOST_MEMBERSHIP_REPORT;
	igmp->igmp_code = 0;
	igmp->igmp_group = inm->inm_addr;
	igmp->igmp_cksum = 0;
	igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);

	imo = &simo;
	bzero((caddr_t)imo, sizeof(*imo));
	imo->imo_multicast_ifp = inm->inm_ifp;
	imo->imo_multicast_ttl = 1;
	/*
	 * Request loopback of the report if we are acting as a multicast
	 * router, so that the process-level routing demon can hear it.
	 */
#ifdef MROUTING
    {
	extern struct socket *ip_mrouter;
	imo->imo_multicast_loop = (ip_mrouter != NULL);
    }
#endif
	ip_output(m, NULL, NULL, 0, imo);

	++igmpstat.igps_snd_reports;
}
Commit	Line	Data
0720a479 KS	1	/*
	2	* Copyright (c) 1988 Stephen Deering.
	3	* Copyright (c) 1992 Regents of the University of California.
	4	* All rights reserved.
	5	*
	6	* This code is derived from software contributed to Berkeley by
	7	* Stephen Deering of Stanford University.
	8	*
	9	* %sccs.include.redist.c%
	10	*
e7a3707f	11	* @(#)igmp.c 8.1 (Berkeley) %G%
0720a479 KS	12	*/
	13
	14	/* Internet Group Management Protocol (IGMP) routines. */
	15
0720a479	16
5548a02f KB	17	#include <sys/param.h>
	18	#include <sys/mbuf.h>
	19	#include <sys/socket.h>
	20	#include <sys/protosw.h>
	21
	22	#include <net/if.h>
	23	#include <net/route.h>
	24
	25	#include <netinet/in.h>
	26	#include <netinet/in_var.h>
	27	#include <netinet/in_systm.h>
	28	#include <netinet/ip.h>
	29	#include <netinet/ip_var.h>
	30	#include <netinet/igmp.h>
	31	#include <netinet/igmp_var.h>
0720a479 KS	32
	33	extern struct ifnet loif;
	34
	35	static int igmp_timers_are_running = 0;
	36	static u_long igmp_all_hosts_group;
	37
	38	static void igmp_sendreport __P((struct in_multi *));
	39
	40	void
	41	igmp_init()
	42	{
	43	/*
	44	* To avoid byte-swapping the same value over and over again.
	45	*/
	46	igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
	47	}
	48
	49	void
	50	igmp_input(m, ifp)
	51	register struct mbuf *m;
	52	register struct ifnet *ifp;
	53	{
	54	register struct igmp *igmp;
	55	register struct ip *ip;
	56	register int igmplen;
	57	register int iphlen;
	58	register int minlen;
	59	register struct in_multi *inm;
	60	register struct in_ifaddr *ia;
	61	struct in_multistep step;
	62
	63	++igmpstat.igps_rcv_total;
	64
	65	ip = mtod(m, struct ip *);
	66	iphlen = ip->ip_hl << 2;
	67	igmplen = ip->ip_len;
	68
	69	/*
	70	* Validate lengths
	71	*/
	72	if (igmplen < IGMP_MINLEN) {
	73	++igmpstat.igps_rcv_tooshort;
	74	m_freem(m);
	75	return;
	76	}
	77	minlen = iphlen + IGMP_MINLEN;
	78	if ((m->m_flags & M_EXT \|\| m->m_len < minlen) &&
	79	(m = m_pullup(m, minlen)) == 0) {
	80	++igmpstat.igps_rcv_tooshort;
	81	return;
	82	}
	83
	84	/*
	85	* Validate checksum
	86	*/
	87	m->m_data += iphlen;
	88	m->m_len -= iphlen;
	89	igmp = mtod(m, struct igmp *);
	90	if (in_cksum(m, igmplen)) {
	91	++igmpstat.igps_rcv_badsum;
	92	m_freem(m);
	93	return;
	94	}
	95	m->m_data -= iphlen;
96	m->m_len += iphlen;
97	ip = mtod(m, struct ip *);
98
99	switch (igmp->igmp_type) {
100
101	case IGMP_HOST_MEMBERSHIP_QUERY:
102	++igmpstat.igps_rcv_queries;
103
104	if (ifp == &loif)
105	break;
106
107	if (ip->ip_dst.s_addr != igmp_all_hosts_group) {
108	++igmpstat.igps_rcv_badqueries;
109	m_freem(m);
110	return;
111	}
112
113	/*
114	* Start the timers in all of our membership records for
115	* the interface on which the query arrived, except those
116	* that are already running and those that belong to the
117	* "all-hosts" group.
118	*/
119	IN_FIRST_MULTI(step, inm);
120	while (inm != NULL) {
121	if (inm->inm_ifp == ifp && inm->inm_timer == 0 &&
122	inm->inm_addr.s_addr != igmp_all_hosts_group) {
123	inm->inm_timer =
124	IGMP_RANDOM_DELAY(inm->inm_addr);
125	igmp_timers_are_running = 1;
126	}
127	IN_NEXT_MULTI(step, inm);
128	}
129
130	break;
131
132	case IGMP_HOST_MEMBERSHIP_REPORT:
133	++igmpstat.igps_rcv_reports;
134
135	if (ifp == &loif)
136	break;
137
138	if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr)) \|\|
139	igmp->igmp_group.s_addr != ip->ip_dst.s_addr) {
140	++igmpstat.igps_rcv_badreports;
141	m_freem(m);
142	return;
143	}
144
145	/*
146	* KLUDGE: if the IP source address of the report has an
147	* unspecified (i.e., zero) subnet number, as is allowed for
148	* a booting host, replace it with the correct subnet number
149	* so that a process-level multicast routing demon can
150	* determine which subnet it arrived from. This is necessary
151	* to compensate for the lack of any way for a process to
152	* determine the arrival interface of an incoming packet.
153	*/
154	if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0) {
155	IFP_TO_IA(ifp, ia);
156	if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
157	}
158
159	/*
160	* If we belong to the group being reported, stop
161	* our timer for that group.
162	*/
163	IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
164	if (inm != NULL) {
165	inm->inm_timer = 0;
166	++igmpstat.igps_rcv_ourreports;
167	}
168
169	break;
170	}
171
172	/*
173	* Pass all valid IGMP packets up to any process(es) listening
174	* on a raw IGMP socket.
175	*/
176	rip_input(m);
177	}
178
179	void
180	igmp_joingroup(inm)
181	struct in_multi *inm;
182	{
183	register int s = splnet();
184
185	if (inm->inm_addr.s_addr == igmp_all_hosts_group \|\|
186	inm->inm_ifp == &loif)
187	inm->inm_timer = 0;
188	else {
189	igmp_sendreport(inm);
190	inm->inm_timer = IGMP_RANDOM_DELAY(inm->inm_addr);
191	igmp_timers_are_running = 1;
192	}
193	splx(s);
194	}
195
196	void
197	igmp_leavegroup(inm)
198	struct in_multi *inm;
199	{
200	/*
201	* No action required on leaving a group.
202	*/
203	}
204
205	void
206	igmp_fasttimo()
207	{
208	register struct in_multi *inm;
209	register int s;
210	struct in_multistep step;
211
212	/*
213	* Quick check to see if any work needs to be done, in order
214	* to minimize the overhead of fasttimo processing.
215	*/
216	if (!igmp_timers_are_running)
217	return;
218
219	s = splnet();
220	igmp_timers_are_running = 0;
221	IN_FIRST_MULTI(step, inm);
222	while (inm != NULL) {
223	if (inm->inm_timer == 0) {
224	/* do nothing */
225	} else if (--inm->inm_timer == 0) {
226	igmp_sendreport(inm);
227	} else {
228	igmp_timers_are_running = 1;
229	}
230	IN_NEXT_MULTI(step, inm);
231	}
232	splx(s);
233	}
234
235	static void
236	igmp_sendreport(inm)
237	register struct in_multi *inm;
238	{
239	register struct mbuf *m;
240	register struct igmp *igmp;
241	register struct ip *ip;
242	register struct ip_moptions *imo;
243	struct ip_moptions simo;
0720a479 KS	244
	245	MGETHDR(m, M_DONTWAIT, MT_HEADER);
	246	if (m == NULL)
	247	return;
	248	m->m_data += max_linkhdr;
	249	m->m_len = sizeof(struct ip) + IGMP_MINLEN;
	250
	251	ip = mtod(m, struct ip *);
	252	ip->ip_tos = 0;
	253	ip->ip_len = sizeof(struct ip) + IGMP_MINLEN;
	254	ip->ip_off = 0;
	255	ip->ip_p = IPPROTO_IGMP;
	256	ip->ip_src.s_addr = INADDR_ANY;
	257	ip->ip_dst = inm->inm_addr;
	258
	259	igmp = (struct igmp *)(ip + 1);
	260	igmp->igmp_type = IGMP_HOST_MEMBERSHIP_REPORT;
	261	igmp->igmp_code = 0;
	262	igmp->igmp_group = inm->inm_addr;
	263	igmp->igmp_cksum = 0;
	264	igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);
	265
	266	imo = &simo;
	267	bzero((caddr_t)imo, sizeof(*imo));
	268	imo->imo_multicast_ifp = inm->inm_ifp;
	269	imo->imo_multicast_ttl = 1;
	270	/*
	271	* Request loopback of the report if we are acting as a multicast
	272	* router, so that the process-level routing demon can hear it.
	273	*/
80fb1f7c KS	274	#ifdef MROUTING
	275	{
	276	extern struct socket *ip_mrouter;
0720a479	277	imo->imo_multicast_loop = (ip_mrouter != NULL);
80fb1f7c KS	278	}
80fb1f7c KS	279	#endif
0720a479 KS	280	ip_output(m, NULL, NULL, 0, imo);
	281
	282	++igmpstat.igps_snd_reports;
	283	}