NetBSD/sys/netinet/igmp.c
tls 8cc016b4bc Protect calls to pool_put/pool_get that may occur in interrupt context
with spl used to protect other allocations and frees, or datastructure
element insertion and removal, in adjacent code.

It is almost unquestionably the case that some of the spl()/splx() calls
added here are superfluous, but it really seems wrong to see:

	s=splfoo();
	/* frob data structure */
	splx(s);
	pool_put(x);

and if we think we need to protect the first operation, then it is hard
to see why we should not think we need to protect the next.  "Better
safe than sorry".

It is also almost unquestionably the case that I missed some pool
gets/puts from interrupt context with my strategy for finding these
calls; use of PR_NOWAIT is a strong hint that a pool may be used from
interrupt context but many callers in the kernel pass a "can wait/can't
wait" flag down such that my searches might not have found them.  One
notable area that needs to be looked at is pf.

See also:

http://mail-index.netbsd.org/tech-kern/2006/07/19/0003.html
http://mail-index.netbsd.org/tech-kern/2006/07/19/0009.html
2006-10-05 17:35:19 +00:00

584 lines
14 KiB
C

/* $NetBSD: igmp.c,v 1.43 2006/10/05 17:35:19 tls 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 1.43 2006/10/05 17:35:19 tls Exp $");
#include "opt_mrouting.h"
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/systm.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>
#include <machine/stdarg.h>
#define IP_MULTICASTOPTS 0
POOL_INIT(igmp_rti_pool, sizeof(struct router_info), 0, 0, 0, "igmppl", NULL);
struct igmpstat igmpstat;
int igmp_timers_are_running;
static LIST_HEAD(, router_info) rti_head = LIST_HEAD_INITIALIZER(rti_head);
void igmp_sendpkt(struct in_multi *, int);
static int rti_fill(struct in_multi *);
static struct router_info *rti_find(struct ifnet *);
static void rti_delete(struct ifnet *);
static int
rti_fill(struct in_multi *inm)
{
struct router_info *rti;
/* this function is called at splsoftnet() */
LIST_FOREACH(rti, &rti_head, rti_link) {
if (rti->rti_ifp == inm->inm_ifp) {
inm->inm_rti = rti;
if (rti->rti_type == IGMP_v1_ROUTER)
return (IGMP_v1_HOST_MEMBERSHIP_REPORT);
else
return (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);
}
static struct router_info *
rti_find(struct ifnet *ifp)
{
struct router_info *rti;
int s = splsoftnet();
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) {
splx(s);
return NULL;
}
rti->rti_ifp = ifp;
rti->rti_type = IGMP_v2_ROUTER;
LIST_INSERT_HEAD(&rti_head, rti, rti_link);
splx(s);
return (rti);
}
static void
rti_delete(struct ifnet *ifp) /* MUST be called at splsoftnet */
{
struct router_info *rti;
LIST_FOREACH(rti, &rti_head, rti_link) {
if (rti->rti_ifp == ifp) {
LIST_REMOVE(rti, rti_link);
pool_put(&igmp_rti_pool, rti);
return;
}
}
}
void
igmp_input(struct mbuf *m, ...)
{
int proto;
int iphlen;
struct ifnet *ifp = m->m_pkthdr.rcvif;
struct ip *ip = mtod(m, struct ip *);
struct igmp *igmp;
u_int minlen;
struct in_multi *inm;
struct in_multistep step;
struct router_info *rti;
struct in_ifaddr *ia;
u_int timer;
va_list ap;
u_int16_t ip_len;
va_start(ap, m);
iphlen = va_arg(ap, int);
proto = va_arg(ap, int);
va_end(ap);
++igmpstat.igps_rcv_total;
/*
* Validate lengths
*/
minlen = iphlen + IGMP_MINLEN;
ip_len = ntohs(ip->ip_len);
if (ip_len < minlen) {
++igmpstat.igps_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)) == 0) {
++igmpstat.igps_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)) {
++igmpstat.igps_rcv_badsum;
m_freem(m);
return;
}
m->m_data -= iphlen;
m->m_len += iphlen;
switch (igmp->igmp_type) {
case IGMP_HOST_MEMBERSHIP_QUERY:
++igmpstat.igps_rcv_queries;
if (ifp->if_flags & IFF_LOOPBACK)
break;
if (igmp->igmp_code == 0) {
rti = rti_find(ifp);
if (rti == NULL)
break;
rti->rti_type = IGMP_v1_ROUTER;
rti->rti_age = 0;
if (ip->ip_dst.s_addr != INADDR_ALLHOSTS_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 a "local" group (224.0.0.X).
*/
IN_FIRST_MULTI(step, inm);
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_are_running = 1;
}
IN_NEXT_MULTI(step, inm);
}
} else {
if (!IN_MULTICAST(ip->ip_dst.s_addr)) {
++igmpstat.igps_rcv_badqueries;
m_freem(m);
return;
}
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_FIRST_MULTI(step, inm);
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_are_running = 1;
break;
case IGMP_SLEEPING_MEMBER:
inm->inm_state =
IGMP_AWAKENING_MEMBER;
break;
}
}
IN_NEXT_MULTI(step, inm);
}
}
break;
case IGMP_v1_HOST_MEMBERSHIP_REPORT:
++igmpstat.igps_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)) {
++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 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) {
IFP_TO_IA(ifp, ia); /* XXX */
if (ia)
ip->ip_src.s_addr = 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;
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;
}
}
break;
case IGMP_v2_HOST_MEMBERSHIP_REPORT:
#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.
*/
IFP_TO_IA(ifp, ia); /* XXX */
if (ia && in_hosteq(ip->ip_src, ia->ia_addr.sin_addr))
break;
#endif
++igmpstat.igps_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)) {
++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 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
IFP_TO_IA(ifp, ia); /* XXX */
#endif
if (ia)
ip->ip_src.s_addr = 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;
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;
}
}
break;
}
/*
* Pass all valid IGMP packets up to any process(es) listening
* on a raw IGMP socket.
*/
rip_input(m, iphlen, proto);
return;
}
int
igmp_joingroup(struct in_multi *inm)
{
int report_type;
int s = splsoftnet();
inm->inm_state = IGMP_IDLE_MEMBER;
if (!IN_LOCAL_GROUP(inm->inm_addr.s_addr) &&
(inm->inm_ifp->if_flags & IFF_LOOPBACK) == 0) {
report_type = rti_fill(inm);
if (report_type == 0) {
splx(s);
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_are_running = 1;
} else
inm->inm_timer = 0;
splx(s);
return 0;
}
void
igmp_leavegroup(struct in_multi *inm)
{
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;
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 = splsoftnet();
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) {
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_are_running = 1;
}
IN_NEXT_MULTI(step, inm);
}
splx(s);
}
void
igmp_slowtimo(void)
{
struct router_info *rti;
int s;
s = splsoftnet();
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;
}
}
splx(s);
}
void
igmp_sendpkt(struct in_multi *inm, int type)
{
struct mbuf *m;
struct igmp *igmp;
struct ip *ip;
struct ip_moptions imo;
#ifdef MROUTING
extern struct socket *ip_mrouter;
#endif /* MROUTING */
MGETHDR(m, M_DONTWAIT, MT_HEADER);
if (m == NULL)
return;
/*
* Assume max_linkhdr + sizeof(struct ip) + IGMP_MINLEN
* is smaller than mbuf size returned by MGETHDR.
*/
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_ifp = inm->inm_ifp;
imo.imo_multicast_ttl = 1;
#ifdef RSVP_ISI
imo.imo_multicast_vif = -1;
#endif
/*
* 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
imo.imo_multicast_loop = (ip_mrouter != NULL);
#else
imo.imo_multicast_loop = 0;
#endif /* MROUTING */
ip_output(m, (struct mbuf *)NULL, (struct route *)NULL,
IP_MULTICASTOPTS, &imo, (struct socket *)NULL);
++igmpstat.igps_snd_reports;
}
void
igmp_purgeif(struct ifnet *ifp) /* MUST be called at splsoftnet() */
{
rti_delete(ifp); /* manipulates pools */
}