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NetBSD/sys/netinet/igmp.c

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/* $NetBSD: igmp.c,v 1.69 2018/09/14 05:09:51 maxv Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* All rights reserved.
*
* 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.
*/
/*
* 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.
*
* MULTICAST Revision: 1.3
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: igmp.c,v 1.69 2018/09/14 05:09:51 maxv Exp $");
#ifdef _KERNEL_OPT
#include "opt_mrouting.h"
#include "opt_net_mpsafe.h"
#endif
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <sys/cprng.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/net_stats.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>
/*
* Per-interface router version information.
*/
typedef struct router_info {
LIST_ENTRY(router_info) rti_link;
ifnet_t * rti_ifp;
int rti_type; /* type of router on this interface */
int rti_age; /* time since last v1 query */
} router_info_t;
/*
* The router-info list and the timer flag are protected by in_multilock.
*
* Lock order:
*
* softnet_lock ->
* in_multilock
*/
static struct pool igmp_rti_pool __cacheline_aligned;
static LIST_HEAD(, router_info) rti_head __cacheline_aligned;
static int igmp_timers_on __cacheline_aligned;
static percpu_t * igmpstat_percpu __read_mostly;
#define IGMP_STATINC(x) _NET_STATINC(igmpstat_percpu, x)
static void igmp_sendpkt(struct in_multi *, int);
static int rti_fill(struct in_multi *);
static router_info_t * rti_find(struct ifnet *);
static void rti_delete(struct ifnet *);
static void sysctl_net_inet_igmp_setup(struct sysctllog **);
/*
* rti_fill: associate router information with the given multicast group;
* if there is no router information for the interface, then create it.
*/
static int
rti_fill(struct in_multi *inm)
{
router_info_t *rti;
KASSERT(in_multi_lock_held());
LIST_FOREACH(rti, &rti_head, rti_link) {
if (rti->rti_ifp == inm->inm_ifp) {
inm->inm_rti = rti;
return rti->rti_type == IGMP_v1_ROUTER ?
IGMP_v1_HOST_MEMBERSHIP_REPORT :
IGMP_v2_HOST_MEMBERSHIP_REPORT;
}
}
rti = pool_get(&igmp_rti_pool, PR_NOWAIT);
if (rti == NULL) {
return 0;
}
rti->rti_ifp = inm->inm_ifp;
rti->rti_type = IGMP_v2_ROUTER;
LIST_INSERT_HEAD(&rti_head, rti, rti_link);
inm->inm_rti = rti;
return IGMP_v2_HOST_MEMBERSHIP_REPORT;
}
/*
* rti_find: lookup or create router information for the given interface.
*/
static router_info_t *
rti_find(ifnet_t *ifp)
{
router_info_t *rti;
KASSERT(in_multi_lock_held());
LIST_FOREACH(rti, &rti_head, rti_link) {
if (rti->rti_ifp == ifp)
return rti;
}
rti = pool_get(&igmp_rti_pool, PR_NOWAIT);
if (rti == NULL) {
return NULL;
}
rti->rti_ifp = ifp;
rti->rti_type = IGMP_v2_ROUTER;
LIST_INSERT_HEAD(&rti_head, rti, rti_link);
return rti;
}
/*
* rti_delete: remove and free the router information entry for the
* given interface.
*/
static void
rti_delete(ifnet_t *ifp)
{
router_info_t *rti;
KASSERT(in_multi_lock_held());
LIST_FOREACH(rti, &rti_head, rti_link) {
if (rti->rti_ifp == ifp) {
LIST_REMOVE(rti, rti_link);
pool_put(&igmp_rti_pool, rti);
break;
}
}
}
void
igmp_init(void)
{
pool_init(&igmp_rti_pool, sizeof(router_info_t), 0, 0, 0,
"igmppl", NULL, IPL_SOFTNET);
igmpstat_percpu = percpu_alloc(sizeof(uint64_t) * IGMP_NSTATS);
sysctl_net_inet_igmp_setup(NULL);
LIST_INIT(&rti_head);
}
void
igmp_input(struct mbuf *m, int off, int proto)
{
ifnet_t *ifp;
struct ip *ip = mtod(m, struct ip *);
struct igmp *igmp;
u_int minlen, timer;
struct in_multi *inm;
struct in_ifaddr *ia;
int ip_len, iphlen;
struct psref psref;
iphlen = off;
IGMP_STATINC(IGMP_STAT_RCV_TOTAL);
/*
* Validate lengths
*/
minlen = iphlen + IGMP_MINLEN;
ip_len = ntohs(ip->ip_len);
if (ip_len < minlen) {
IGMP_STATINC(IGMP_STAT_RCV_TOOSHORT);
m_freem(m);
return;
}
if (((m->m_flags & M_EXT) && (ip->ip_src.s_addr & IN_CLASSA_NET) == 0)
|| m->m_len < minlen) {
if ((m = m_pullup(m, minlen)) == NULL) {
IGMP_STATINC(IGMP_STAT_RCV_TOOSHORT);
return;
}
ip = mtod(m, struct ip *);
}
/*
* Validate checksum
*/
m->m_data += iphlen;
m->m_len -= iphlen;
igmp = mtod(m, struct igmp *);
/* No need to assert alignment here. */
if (in_cksum(m, ip_len - iphlen)) {
IGMP_STATINC(IGMP_STAT_RCV_BADSUM);
m_freem(m);
return;
}
m->m_data -= iphlen;
m->m_len += iphlen;
ifp = m_get_rcvif_psref(m, &psref);
if (__predict_false(ifp == NULL))
goto drop;
switch (igmp->igmp_type) {
case IGMP_HOST_MEMBERSHIP_QUERY:
IGMP_STATINC(IGMP_STAT_RCV_QUERIES);
if (ifp->if_flags & IFF_LOOPBACK)
break;
if (igmp->igmp_code == 0) {
struct in_multistep step;
router_info_t *rti;
if (ip->ip_dst.s_addr != INADDR_ALLHOSTS_GROUP) {
IGMP_STATINC(IGMP_STAT_RCV_BADQUERIES);
goto drop;
}
in_multi_lock(RW_WRITER);
rti = rti_find(ifp);
if (rti == NULL) {
in_multi_unlock();
break;
}
rti->rti_type = IGMP_v1_ROUTER;
rti->rti_age = 0;
/*
* 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 a "local" group (224.0.0.X).
*/
inm = in_first_multi(&step);
while (inm != NULL) {
if (inm->inm_ifp == ifp &&
inm->inm_timer == 0 &&
!IN_LOCAL_GROUP(inm->inm_addr.s_addr)) {
inm->inm_state = IGMP_DELAYING_MEMBER;
inm->inm_timer = IGMP_RANDOM_DELAY(
IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ);
igmp_timers_on = true;
}
inm = in_next_multi(&step);
}
in_multi_unlock();
} else {
struct in_multistep step;
if (!IN_MULTICAST(ip->ip_dst.s_addr)) {
IGMP_STATINC(IGMP_STAT_RCV_BADQUERIES);
goto drop;
}
timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
if (timer == 0)
timer = 1;
/*
* 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 a "local" group (224.0.0.X). For
* timers already running, check if they need to be
* reset.
*/
in_multi_lock(RW_WRITER);
inm = in_first_multi(&step);
while (inm != NULL) {
if (inm->inm_ifp == ifp &&
!IN_LOCAL_GROUP(inm->inm_addr.s_addr) &&
(ip->ip_dst.s_addr == INADDR_ALLHOSTS_GROUP ||
in_hosteq(ip->ip_dst, inm->inm_addr))) {
switch (inm->inm_state) {
case IGMP_DELAYING_MEMBER:
if (inm->inm_timer <= timer)
break;
/* FALLTHROUGH */
case IGMP_IDLE_MEMBER:
case IGMP_LAZY_MEMBER:
case IGMP_AWAKENING_MEMBER:
inm->inm_state =
IGMP_DELAYING_MEMBER;
inm->inm_timer =
IGMP_RANDOM_DELAY(timer);
igmp_timers_on = true;
break;
case IGMP_SLEEPING_MEMBER:
inm->inm_state =
IGMP_AWAKENING_MEMBER;
break;
}
}
inm = in_next_multi(&step);
}
in_multi_unlock();
}
break;
case IGMP_v1_HOST_MEMBERSHIP_REPORT:
IGMP_STATINC(IGMP_STAT_RCV_REPORTS);
if (ifp->if_flags & IFF_LOOPBACK)
break;
if (!IN_MULTICAST(igmp->igmp_group.s_addr) ||
!in_hosteq(igmp->igmp_group, ip->ip_dst)) {
IGMP_STATINC(IGMP_STAT_RCV_BADREPORTS);
goto drop;
}
/*
* 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 daemon 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 ((ip->ip_src.s_addr & IN_CLASSA_NET) == 0) {
int s = pserialize_read_enter();
ia = in_get_ia_from_ifp(ifp); /* XXX */
if (ia)
ip->ip_src.s_addr = ia->ia_subnet;
pserialize_read_exit(s);
}
/*
* If we belong to the group being reported, stop
* our timer for that group.
*/
in_multi_lock(RW_WRITER);
inm = in_lookup_multi(igmp->igmp_group, ifp);
if (inm != NULL) {
inm->inm_timer = 0;
IGMP_STATINC(IGMP_STAT_RCV_OURREPORTS);
switch (inm->inm_state) {
case IGMP_IDLE_MEMBER:
case IGMP_LAZY_MEMBER:
case IGMP_AWAKENING_MEMBER:
case IGMP_SLEEPING_MEMBER:
inm->inm_state = IGMP_SLEEPING_MEMBER;
break;
case IGMP_DELAYING_MEMBER:
if (inm->inm_rti->rti_type == IGMP_v1_ROUTER)
inm->inm_state = IGMP_LAZY_MEMBER;
else
inm->inm_state = IGMP_SLEEPING_MEMBER;
break;
}
}
in_multi_unlock();
break;
case IGMP_v2_HOST_MEMBERSHIP_REPORT: {
int s = pserialize_read_enter();
#ifdef MROUTING
/*
* Make sure we don't hear our own membership report. Fast
* leave requires knowing that we are the only member of a
* group.
*/
ia = in_get_ia_from_ifp(ifp); /* XXX */
if (ia && in_hosteq(ip->ip_src, ia->ia_addr.sin_addr)) {
pserialize_read_exit(s);
break;
}
#endif
IGMP_STATINC(IGMP_STAT_RCV_REPORTS);
if (ifp->if_flags & IFF_LOOPBACK) {
pserialize_read_exit(s);
break;
}
if (!IN_MULTICAST(igmp->igmp_group.s_addr) ||
!in_hosteq(igmp->igmp_group, ip->ip_dst)) {
IGMP_STATINC(IGMP_STAT_RCV_BADREPORTS);
pserialize_read_exit(s);
goto drop;
}
/*
* 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 daemon 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 ((ip->ip_src.s_addr & IN_CLASSA_NET) == 0) {
#ifndef MROUTING
ia = in_get_ia_from_ifp(ifp); /* XXX */
#endif
if (ia)
ip->ip_src.s_addr = ia->ia_subnet;
}
pserialize_read_exit(s);
/*
* If we belong to the group being reported, stop
* our timer for that group.
*/
in_multi_lock(RW_WRITER);
inm = in_lookup_multi(igmp->igmp_group, ifp);
if (inm != NULL) {
inm->inm_timer = 0;
IGMP_STATINC(IGMP_STAT_RCV_OURREPORTS);
switch (inm->inm_state) {
case IGMP_DELAYING_MEMBER:
case IGMP_IDLE_MEMBER:
case IGMP_AWAKENING_MEMBER:
inm->inm_state = IGMP_LAZY_MEMBER;
break;
case IGMP_LAZY_MEMBER:
case IGMP_SLEEPING_MEMBER:
break;
}
}
in_multi_unlock();
break;
}
}
m_put_rcvif_psref(ifp, &psref);
/*
* Pass all valid IGMP packets up to any process(es) listening
* on a raw IGMP socket.
*/
/*
* Currently, igmp_input() is always called holding softnet_lock
* by ipintr()(!NET_MPSAFE) or PR_INPUT_WRAP()(NET_MPSAFE).
*/
KASSERT(mutex_owned(softnet_lock));
rip_input(m, iphlen, proto);
return;
drop:
m_put_rcvif_psref(ifp, &psref);
m_freem(m);
return;
}
int
igmp_joingroup(struct in_multi *inm)
{
KASSERT(in_multi_lock_held());
inm->inm_state = IGMP_IDLE_MEMBER;
if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) &&
(inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0) {
int report_type;
report_type = rti_fill(inm);
if (report_type == 0) {
return ENOMEM;
}
igmp_sendpkt(inm, report_type);
inm->inm_state = IGMP_DELAYING_MEMBER;
inm->inm_timer = IGMP_RANDOM_DELAY(
IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ);
igmp_timers_on = true;
} else
inm->inm_timer = 0;
return 0;
}
void
igmp_leavegroup(struct in_multi *inm)
{
KASSERT(in_multi_lock_held());
switch (inm->inm_state) {
case IGMP_DELAYING_MEMBER:
case IGMP_IDLE_MEMBER:
if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) &&
(inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0)
if (inm->inm_rti->rti_type != IGMP_v1_ROUTER)
igmp_sendpkt(inm, IGMP_HOST_LEAVE_MESSAGE);
break;
case IGMP_LAZY_MEMBER:
case IGMP_AWAKENING_MEMBER:
case IGMP_SLEEPING_MEMBER:
break;
}
}
void
igmp_fasttimo(void)
{
struct in_multi *inm;
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_on) {
return;
}
/* XXX: Needed for ip_output(). */
SOFTNET_LOCK_UNLESS_NET_MPSAFE();
in_multi_lock(RW_WRITER);
igmp_timers_on = false;
inm = in_first_multi(&step);
while (inm != NULL) {
if (inm->inm_timer == 0) {
/* do nothing */
} else if (--inm->inm_timer == 0) {
if (inm->inm_state == IGMP_DELAYING_MEMBER) {
if (inm->inm_rti->rti_type == IGMP_v1_ROUTER)
igmp_sendpkt(inm,
IGMP_v1_HOST_MEMBERSHIP_REPORT);
else
igmp_sendpkt(inm,
IGMP_v2_HOST_MEMBERSHIP_REPORT);
inm->inm_state = IGMP_IDLE_MEMBER;
}
} else {
igmp_timers_on = true;
}
inm = in_next_multi(&step);
}
in_multi_unlock();
SOFTNET_UNLOCK_UNLESS_NET_MPSAFE();
}
void
igmp_slowtimo(void)
{
router_info_t *rti;
in_multi_lock(RW_WRITER);
LIST_FOREACH(rti, &rti_head, rti_link) {
if (rti->rti_type == IGMP_v1_ROUTER &&
++rti->rti_age >= IGMP_AGE_THRESHOLD) {
rti->rti_type = IGMP_v2_ROUTER;
}
}
in_multi_unlock();
}
/*
* igmp_sendpkt: construct an IGMP packet, given the multicast structure
* and the type, and send the datagram.
*/
static void
igmp_sendpkt(struct in_multi *inm, int type)
{
struct mbuf *m;
struct igmp *igmp;
struct ip *ip;
struct ip_moptions imo;
KASSERT(in_multi_lock_held());
MGETHDR(m, M_DONTWAIT, MT_HEADER);
if (m == NULL)
return;
KASSERT(max_linkhdr + sizeof(struct ip) + IGMP_MINLEN <= MHLEN);
m->m_data += max_linkhdr;
m->m_len = sizeof(struct ip) + IGMP_MINLEN;
m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
ip = mtod(m, struct ip *);
ip->ip_tos = 0;
ip->ip_len = htons(sizeof(struct ip) + IGMP_MINLEN);
ip->ip_off = htons(0);
ip->ip_p = IPPROTO_IGMP;
ip->ip_src = zeroin_addr;
ip->ip_dst = inm->inm_addr;
m->m_data += sizeof(struct ip);
m->m_len -= sizeof(struct ip);
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);
imo.imo_multicast_if_index = if_get_index(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);
#else
imo.imo_multicast_loop = 0;
#endif
/*
* Note: IP_IGMP_MCAST indicates that in_multilock is held.
* The caller must still acquire softnet_lock for ip_output().
*/
#ifndef NET_MPSAFE
KASSERT(mutex_owned(softnet_lock));
#endif
ip_output(m, NULL, NULL, IP_IGMP_MCAST, &imo, NULL);
IGMP_STATINC(IGMP_STAT_SND_REPORTS);
}
void
igmp_purgeif(ifnet_t *ifp)
{
in_multi_lock(RW_WRITER);
rti_delete(ifp);
in_multi_unlock();
}
static int
sysctl_net_inet_igmp_stats(SYSCTLFN_ARGS)
{
return NETSTAT_SYSCTL(igmpstat_percpu, IGMP_NSTATS);
}
static void
sysctl_net_inet_igmp_setup(struct sysctllog **clog)
{
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "inet", NULL,
NULL, 0, NULL, 0,
CTL_NET, PF_INET, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "igmp",
SYSCTL_DESCR("Internet Group Management Protocol"),
NULL, 0, NULL, 0,
CTL_NET, PF_INET, IPPROTO_IGMP, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRUCT, "stats",
SYSCTL_DESCR("IGMP statistics"),
sysctl_net_inet_igmp_stats, 0, NULL, 0,
CTL_NET, PF_INET, IPPROTO_IGMP, CTL_CREATE, CTL_EOL);
}
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