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igmp.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linux NET3: Internet Group Management Protocol [IGMP]
*
* This code implements the IGMP protocol as defined in RFC1112. There has
* been a further revision of this protocol since which is now supported.
*
* If you have trouble with this module be careful what gcc you have used,
* the older version didn't come out right using gcc 2.5.8, the newer one
* seems to fall out with gcc 2.6.2.
*
* Authors:
* Alan Cox <alan@lxorguk.ukuu.org.uk>
*
* Fixes:
*
* Alan Cox : Added lots of __inline__ to optimise
* the memory usage of all the tiny little
* functions.
* Alan Cox : Dumped the header building experiment.
* Alan Cox : Minor tweaks ready for multicast routing
* and extended IGMP protocol.
* Alan Cox : Removed a load of inline directives. Gcc 2.5.8
* writes utterly bogus code otherwise (sigh)
* fixed IGMP loopback to behave in the manner
* desired by mrouted, fixed the fact it has been
* broken since 1.3.6 and cleaned up a few minor
* points.
*
* Chih-Jen Chang : Tried to revise IGMP to Version 2
* Tsu-Sheng Tsao E-mail: chihjenc@scf.usc.edu and tsusheng@scf.usc.edu
* The enhancements are mainly based on Steve Deering's
* ipmulti-3.5 source code.
* Chih-Jen Chang : Added the igmp_get_mrouter_info and
* Tsu-Sheng Tsao igmp_set_mrouter_info to keep track of
* the mrouted version on that device.
* Chih-Jen Chang : Added the max_resp_time parameter to
* Tsu-Sheng Tsao igmp_heard_query(). Using this parameter
* to identify the multicast router version
* and do what the IGMP version 2 specified.
* Chih-Jen Chang : Added a timer to revert to IGMP V2 router
* Tsu-Sheng Tsao if the specified time expired.
* Alan Cox : Stop IGMP from 0.0.0.0 being accepted.
* Alan Cox : Use GFP_ATOMIC in the right places.
* Christian Daudt : igmp timer wasn't set for local group
* memberships but was being deleted,
* which caused a "del_timer() called
* from %p with timer not initialized\n"
* message (960131).
* Christian Daudt : removed del_timer from
* igmp_timer_expire function (960205).
* Christian Daudt : igmp_heard_report now only calls
* igmp_timer_expire if tm->running is
* true (960216).
* Malcolm Beattie : ttl comparison wrong in igmp_rcv made
* igmp_heard_query never trigger. Expiry
* miscalculation fixed in igmp_heard_query
* and random() made to return unsigned to
* prevent negative expiry times.
* Alexey Kuznetsov: Wrong group leaving behaviour, backport
* fix from pending 2.1.x patches.
* Alan Cox: Forget to enable FDDI support earlier.
* Alexey Kuznetsov: Fixed leaving groups on device down.
* Alexey Kuznetsov: Accordance to igmp-v2-06 draft.
* David L Stevens: IGMPv3 support, with help from
* Vinay Kulkarni
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/if_arp.h>
#include <linux/rtnetlink.h>
#include <linux/times.h>
#include <linux/pkt_sched.h>
#include <linux/byteorder/generic.h>
#include <net/net_namespace.h>
#include <net/arp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/sock.h>
#include <net/checksum.h>
#include <net/inet_common.h>
#include <linux/netfilter_ipv4.h>
#ifdef CONFIG_IP_MROUTE
#include <linux/mroute.h>
#endif
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#endif
#ifdef CONFIG_IP_MULTICAST
/* Parameter names and values are taken from igmp-v2-06 draft */
#define IGMP_QUERY_INTERVAL (125*HZ)
#define IGMP_QUERY_RESPONSE_INTERVAL (10*HZ)
#define IGMP_INITIAL_REPORT_DELAY (1)
/* IGMP_INITIAL_REPORT_DELAY is not from IGMP specs!
* IGMP specs require to report membership immediately after
* joining a group, but we delay the first report by a
* small interval. It seems more natural and still does not
* contradict to specs provided this delay is small enough.
*/
#define IGMP_V1_SEEN(in_dev) \
(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 1 || \
IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 1 || \
((in_dev)->mr_v1_seen && \
time_before(jiffies, (in_dev)->mr_v1_seen)))
#define IGMP_V2_SEEN(in_dev) \
(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 2 || \
IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 2 || \
((in_dev)->mr_v2_seen && \
time_before(jiffies, (in_dev)->mr_v2_seen)))
static int unsolicited_report_interval(struct in_device *in_dev)
{
int interval_ms, interval_jiffies;
if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev))
interval_ms = IN_DEV_CONF_GET(
in_dev,
IGMPV2_UNSOLICITED_REPORT_INTERVAL);
else /* v3 */
interval_ms = IN_DEV_CONF_GET(
in_dev,
IGMPV3_UNSOLICITED_REPORT_INTERVAL);
interval_jiffies = msecs_to_jiffies(interval_ms);
/* _timer functions can't handle a delay of 0 jiffies so ensure
* we always return a positive value.
*/
if (interval_jiffies <= 0)
interval_jiffies = 1;
return interval_jiffies;
}
static void igmpv3_add_delrec(struct in_device *in_dev, struct ip_mc_list *im,
gfp_t gfp);
static void igmpv3_del_delrec(struct in_device *in_dev, struct ip_mc_list *im);
static void igmpv3_clear_delrec(struct in_device *in_dev);
static int sf_setstate(struct ip_mc_list *pmc);
static void sf_markstate(struct ip_mc_list *pmc);
#endif
static void ip_mc_clear_src(struct ip_mc_list *pmc);
static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode,
int sfcount, __be32 *psfsrc, int delta);
static void ip_ma_put(struct ip_mc_list *im)
{
if (refcount_dec_and_test(&im->refcnt)) {
in_dev_put(im->interface);
kfree_rcu(im, rcu);
}
}
#define for_each_pmc_rcu(in_dev, pmc) \
for (pmc = rcu_dereference(in_dev->mc_list); \
pmc != NULL; \
pmc = rcu_dereference(pmc->next_rcu))
#define for_each_pmc_rtnl(in_dev, pmc) \
for (pmc = rtnl_dereference(in_dev->mc_list); \
pmc != NULL; \
pmc = rtnl_dereference(pmc->next_rcu))
static void ip_sf_list_clear_all(struct ip_sf_list *psf)
{
struct ip_sf_list *next;
while (psf) {
next = psf->sf_next;
kfree(psf);
psf = next;
}
}
#ifdef CONFIG_IP_MULTICAST
/*
* Timer management
*/
static void igmp_stop_timer(struct ip_mc_list *im)
{
spin_lock_bh(&im->lock);
if (del_timer(&im->timer))
refcount_dec(&im->refcnt);
im->tm_running = 0;
im->reporter = 0;
im->unsolicit_count = 0;
spin_unlock_bh(&im->lock);
}
/* It must be called with locked im->lock */
static void igmp_start_timer(struct ip_mc_list *im, int max_delay)
{
int tv = prandom_u32() % max_delay;
im->tm_running = 1;
if (!mod_timer(&im->timer, jiffies+tv+2))
refcount_inc(&im->refcnt);
}
static void igmp_gq_start_timer(struct in_device *in_dev)
{
int tv = prandom_u32() % in_dev->mr_maxdelay;
unsigned long exp = jiffies + tv + 2;
if (in_dev->mr_gq_running &&
time_after_eq(exp, (in_dev->mr_gq_timer).expires))
return;
in_dev->mr_gq_running = 1;
if (!mod_timer(&in_dev->mr_gq_timer, exp))
in_dev_hold(in_dev);
}
static void igmp_ifc_start_timer(struct in_device *in_dev, int delay)
{
int tv = prandom_u32() % delay;
if (!mod_timer(&in_dev->mr_ifc_timer, jiffies+tv+2))
in_dev_hold(in_dev);
}
static void igmp_mod_timer(struct ip_mc_list *im, int max_delay)
{
spin_lock_bh(&im->lock);
im->unsolicit_count = 0;
if (del_timer(&im->timer)) {
if ((long)(im->timer.expires-jiffies) < max_delay) {
add_timer(&im->timer);
im->tm_running = 1;
spin_unlock_bh(&im->lock);
return;
}
refcount_dec(&im->refcnt);
}
igmp_start_timer(im, max_delay);
spin_unlock_bh(&im->lock);
}
/*
* Send an IGMP report.
*/
#define IGMP_SIZE (sizeof(struct igmphdr)+sizeof(struct iphdr)+4)
static int is_in(struct ip_mc_list *pmc, struct ip_sf_list *psf, int type,
int gdeleted, int sdeleted)
{
switch (type) {
case IGMPV3_MODE_IS_INCLUDE:
case IGMPV3_MODE_IS_EXCLUDE:
if (gdeleted || sdeleted)
return 0;
if (!(pmc->gsquery && !psf->sf_gsresp)) {
if (pmc->sfmode == MCAST_INCLUDE)
return 1;
/* don't include if this source is excluded
* in all filters
*/
if (psf->sf_count[MCAST_INCLUDE])
return type == IGMPV3_MODE_IS_INCLUDE;
return pmc->sfcount[MCAST_EXCLUDE] ==
psf->sf_count[MCAST_EXCLUDE];
}
return 0;
case IGMPV3_CHANGE_TO_INCLUDE:
if (gdeleted || sdeleted)
return 0;
return psf->sf_count[MCAST_INCLUDE] != 0;
case IGMPV3_CHANGE_TO_EXCLUDE:
if (gdeleted || sdeleted)
return 0;
if (pmc->sfcount[MCAST_EXCLUDE] == 0 ||
psf->sf_count[MCAST_INCLUDE])
return 0;
return pmc->sfcount[MCAST_EXCLUDE] ==
psf->sf_count[MCAST_EXCLUDE];
case IGMPV3_ALLOW_NEW_SOURCES:
if (gdeleted || !psf->sf_crcount)
return 0;
return (pmc->sfmode == MCAST_INCLUDE) ^ sdeleted;
case IGMPV3_BLOCK_OLD_SOURCES:
if (pmc->sfmode == MCAST_INCLUDE)
return gdeleted || (psf->sf_crcount && sdeleted);
return psf->sf_crcount && !gdeleted && !sdeleted;
}
return 0;
}
static int
igmp_scount(struct ip_mc_list *pmc, int type, int gdeleted, int sdeleted)
{
struct ip_sf_list *psf;
int scount = 0;
for (psf = pmc->sources; psf; psf = psf->sf_next) {
if (!is_in(pmc, psf, type, gdeleted, sdeleted))
continue;
scount++;
}
return scount;
}
/* source address selection per RFC 3376 section 4.2.13 */
static __be32 igmpv3_get_srcaddr(struct net_device *dev,
const struct flowi4 *fl4)
{
struct in_device *in_dev = __in_dev_get_rcu(dev);
const struct in_ifaddr *ifa;
if (!in_dev)
return htonl(INADDR_ANY);
in_dev_for_each_ifa_rcu(ifa, in_dev) {
if (fl4->saddr == ifa->ifa_local)
return fl4->saddr;
}
return htonl(INADDR_ANY);
}
static struct sk_buff *igmpv3_newpack(struct net_device *dev, unsigned int mtu)
{
struct sk_buff *skb;
struct rtable *rt;
struct iphdr *pip;
struct igmpv3_report *pig;
struct net *net = dev_net(dev);
struct flowi4 fl4;
int hlen = LL_RESERVED_SPACE(dev);
int tlen = dev->needed_tailroom;
unsigned int size = mtu;
while (1) {
skb = alloc_skb(size + hlen + tlen,
GFP_ATOMIC | __GFP_NOWARN);
if (skb)
break;
size >>= 1;
if (size < 256)
return NULL;
}
skb->priority = TC_PRIO_CONTROL;
rt = ip_route_output_ports(net, &fl4, NULL, IGMPV3_ALL_MCR, 0,
0, 0,
IPPROTO_IGMP, 0, dev->ifindex);
if (IS_ERR(rt)) {
kfree_skb(skb);
return NULL;
}
skb_dst_set(skb, &rt->dst);
skb->dev = dev;
skb_reserve(skb, hlen);
skb_tailroom_reserve(skb, mtu, tlen);
skb_reset_network_header(skb);
pip = ip_hdr(skb);
skb_put(skb, sizeof(struct iphdr) + 4);
pip->version = 4;
pip->ihl = (sizeof(struct iphdr)+4)>>2;
pip->tos = 0xc0;
pip->frag_off = htons(IP_DF);
pip->ttl = 1;
pip->daddr = fl4.daddr;
rcu_read_lock();
pip->saddr = igmpv3_get_srcaddr(dev, &fl4);
rcu_read_unlock();
pip->protocol = IPPROTO_IGMP;
pip->tot_len = 0; /* filled in later */
ip_select_ident(net, skb, NULL);
((u8 *)&pip[1])[0] = IPOPT_RA;
((u8 *)&pip[1])[1] = 4;
((u8 *)&pip[1])[2] = 0;
((u8 *)&pip[1])[3] = 0;
skb->transport_header = skb->network_header + sizeof(struct iphdr) + 4;
skb_put(skb, sizeof(*pig));
pig = igmpv3_report_hdr(skb);
pig->type = IGMPV3_HOST_MEMBERSHIP_REPORT;
pig->resv1 = 0;
pig->csum = 0;
pig->resv2 = 0;
pig->ngrec = 0;
return skb;
}
static int igmpv3_sendpack(struct sk_buff *skb)
{
struct igmphdr *pig = igmp_hdr(skb);
const int igmplen = skb_tail_pointer(skb) - skb_transport_header(skb);
pig->csum = ip_compute_csum(igmp_hdr(skb), igmplen);
return ip_local_out(dev_net(skb_dst(skb)->dev), skb->sk, skb);
}
static int grec_size(struct ip_mc_list *pmc, int type, int gdel, int sdel)
{
return sizeof(struct igmpv3_grec) + 4*igmp_scount(pmc, type, gdel, sdel);
}
static struct sk_buff *add_grhead(struct sk_buff *skb, struct ip_mc_list *pmc,
int type, struct igmpv3_grec **ppgr, unsigned int mtu)
{
struct net_device *dev = pmc->interface->dev;
struct igmpv3_report *pih;
struct igmpv3_grec *pgr;
if (!skb) {
skb = igmpv3_newpack(dev, mtu);
if (!skb)
return NULL;
}
pgr = skb_put(skb, sizeof(struct igmpv3_grec));
pgr->grec_type = type;
pgr->grec_auxwords = 0;
pgr->grec_nsrcs = 0;
pgr->grec_mca = pmc->multiaddr;
pih = igmpv3_report_hdr(skb);
pih->ngrec = htons(ntohs(pih->ngrec)+1);
*ppgr = pgr;
return skb;
}
#define AVAILABLE(skb) ((skb) ? skb_availroom(skb) : 0)
static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
int type, int gdeleted, int sdeleted)
{
struct net_device *dev = pmc->interface->dev;
struct net *net = dev_net(dev);
struct igmpv3_report *pih;
struct igmpv3_grec *pgr = NULL;
struct ip_sf_list *psf, *psf_next, *psf_prev, **psf_list;
int scount, stotal, first, isquery, truncate;
unsigned int mtu;
if (pmc->multiaddr == IGMP_ALL_HOSTS)
return skb;
if (ipv4_is_local_multicast(pmc->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)
return skb;
mtu = READ_ONCE(dev->mtu);
if (mtu < IPV4_MIN_MTU)
return skb;
isquery = type == IGMPV3_MODE_IS_INCLUDE ||
type == IGMPV3_MODE_IS_EXCLUDE;
truncate = type == IGMPV3_MODE_IS_EXCLUDE ||
type == IGMPV3_CHANGE_TO_EXCLUDE;
stotal = scount = 0;
psf_list = sdeleted ? &pmc->tomb : &pmc->sources;
if (!*psf_list)
goto empty_source;
pih = skb ? igmpv3_report_hdr(skb) : NULL;
/* EX and TO_EX get a fresh packet, if needed */
if (truncate) {
if (pih && pih->ngrec &&
AVAILABLE(skb) < grec_size(pmc, type, gdeleted, sdeleted)) {
if (skb)
igmpv3_sendpack(skb);
skb = igmpv3_newpack(dev, mtu);
}
}
first = 1;
psf_prev = NULL;
for (psf = *psf_list; psf; psf = psf_next) {
__be32 *psrc;
psf_next = psf->sf_next;
if (!is_in(pmc, psf, type, gdeleted, sdeleted)) {
psf_prev = psf;
continue;
}
/* Based on RFC3376 5.1. Should not send source-list change
* records when there is a filter mode change.
*/
if (((gdeleted && pmc->sfmode == MCAST_EXCLUDE) ||
(!gdeleted && pmc->crcount)) &&
(type == IGMPV3_ALLOW_NEW_SOURCES ||
type == IGMPV3_BLOCK_OLD_SOURCES) && psf->sf_crcount)
goto decrease_sf_crcount;
/* clear marks on query responses */
if (isquery)
psf->sf_gsresp = 0;
if (AVAILABLE(skb) < sizeof(__be32) +
first*sizeof(struct igmpv3_grec)) {
if (truncate && !first)
break; /* truncate these */
if (pgr)
pgr->grec_nsrcs = htons(scount);
if (skb)
igmpv3_sendpack(skb);
skb = igmpv3_newpack(dev, mtu);
first = 1;
scount = 0;
}
if (first) {
skb = add_grhead(skb, pmc, type, &pgr, mtu);
first = 0;
}
if (!skb)
return NULL;
psrc = skb_put(skb, sizeof(__be32));
*psrc = psf->sf_inaddr;
scount++; stotal++;
if ((type == IGMPV3_ALLOW_NEW_SOURCES ||
type == IGMPV3_BLOCK_OLD_SOURCES) && psf->sf_crcount) {
decrease_sf_crcount:
psf->sf_crcount--;
if ((sdeleted || gdeleted) && psf->sf_crcount == 0) {
if (psf_prev)
psf_prev->sf_next = psf->sf_next;
else
*psf_list = psf->sf_next;
kfree(psf);
continue;
}
}
psf_prev = psf;
}
empty_source:
if (!stotal) {
if (type == IGMPV3_ALLOW_NEW_SOURCES ||
type == IGMPV3_BLOCK_OLD_SOURCES)
return skb;
if (pmc->crcount || isquery) {
/* make sure we have room for group header */
if (skb && AVAILABLE(skb) < sizeof(struct igmpv3_grec)) {
igmpv3_sendpack(skb);
skb = NULL; /* add_grhead will get a new one */
}
skb = add_grhead(skb, pmc, type, &pgr, mtu);
}
}
if (pgr)
pgr->grec_nsrcs = htons(scount);
if (isquery)
pmc->gsquery = 0; /* clear query state on report */
return skb;
}
static int igmpv3_send_report(struct in_device *in_dev, struct ip_mc_list *pmc)
{
struct sk_buff *skb = NULL;
struct net *net = dev_net(in_dev->dev);
int type;
if (!pmc) {
rcu_read_lock();
for_each_pmc_rcu(in_dev, pmc) {
if (pmc->multiaddr == IGMP_ALL_HOSTS)
continue;
if (ipv4_is_local_multicast(pmc->multiaddr) &&
!net->ipv4.sysctl_igmp_llm_reports)
continue;
spin_lock_bh(&pmc->lock);
if (pmc->sfcount[MCAST_EXCLUDE])
type = IGMPV3_MODE_IS_EXCLUDE;
else
type = IGMPV3_MODE_IS_INCLUDE;
skb = add_grec(skb, pmc, type, 0, 0);
spin_unlock_bh(&pmc->lock);
}
rcu_read_unlock();
} else {
spin_lock_bh(&pmc->lock);
if (pmc->sfcount[MCAST_EXCLUDE])
type = IGMPV3_MODE_IS_EXCLUDE;
else
type = IGMPV3_MODE_IS_INCLUDE;
skb = add_grec(skb, pmc, type, 0, 0);
spin_unlock_bh(&pmc->lock);
}
if (!skb)
return 0;
return igmpv3_sendpack(skb);
}
/*
* remove zero-count source records from a source filter list
*/
static void igmpv3_clear_zeros(struct ip_sf_list **ppsf)
{
struct ip_sf_list *psf_prev, *psf_next, *psf;
psf_prev = NULL;
for (psf = *ppsf; psf; psf = psf_next) {
psf_next = psf->sf_next;
if (psf->sf_crcount == 0) {
if (psf_prev)
psf_prev->sf_next = psf->sf_next;
else
*ppsf = psf->sf_next;
kfree(psf);
} else
psf_prev = psf;
}
}
static void kfree_pmc(struct ip_mc_list *pmc)
{
ip_sf_list_clear_all(pmc->sources);
ip_sf_list_clear_all(pmc->tomb);
kfree(pmc);
}
static void igmpv3_send_cr(struct in_device *in_dev)
{
struct ip_mc_list *pmc, *pmc_prev, *pmc_next;
struct sk_buff *skb = NULL;
int type, dtype;
rcu_read_lock();
spin_lock_bh(&in_dev->mc_tomb_lock);
/* deleted MCA's */
pmc_prev = NULL;
for (pmc = in_dev->mc_tomb; pmc; pmc = pmc_next) {
pmc_next = pmc->next;
if (pmc->sfmode == MCAST_INCLUDE) {
type = IGMPV3_BLOCK_OLD_SOURCES;
dtype = IGMPV3_BLOCK_OLD_SOURCES;
skb = add_grec(skb, pmc, type, 1, 0);
skb = add_grec(skb, pmc, dtype, 1, 1);
}
if (pmc->crcount) {
if (pmc->sfmode == MCAST_EXCLUDE) {
type = IGMPV3_CHANGE_TO_INCLUDE;
skb = add_grec(skb, pmc, type, 1, 0);
}
pmc->crcount--;
if (pmc->crcount == 0) {
igmpv3_clear_zeros(&pmc->tomb);
igmpv3_clear_zeros(&pmc->sources);
}
}
if (pmc->crcount == 0 && !pmc->tomb && !pmc->sources) {
if (pmc_prev)
pmc_prev->next = pmc_next;
else
in_dev->mc_tomb = pmc_next;
in_dev_put(pmc->interface);
kfree_pmc(pmc);
} else
pmc_prev = pmc;
}
spin_unlock_bh(&in_dev->mc_tomb_lock);
/* change recs */
for_each_pmc_rcu(in_dev, pmc) {
spin_lock_bh(&pmc->lock);
if (pmc->sfcount[MCAST_EXCLUDE]) {
type = IGMPV3_BLOCK_OLD_SOURCES;
dtype = IGMPV3_ALLOW_NEW_SOURCES;
} else {
type = IGMPV3_ALLOW_NEW_SOURCES;
dtype = IGMPV3_BLOCK_OLD_SOURCES;
}
skb = add_grec(skb, pmc, type, 0, 0);
skb = add_grec(skb, pmc, dtype, 0, 1); /* deleted sources */
/* filter mode changes */
if (pmc->crcount) {
if (pmc->sfmode == MCAST_EXCLUDE)
type = IGMPV3_CHANGE_TO_EXCLUDE;
else
type = IGMPV3_CHANGE_TO_INCLUDE;
skb = add_grec(skb, pmc, type, 0, 0);
pmc->crcount--;
}
spin_unlock_bh(&pmc->lock);
}
rcu_read_unlock();
if (!skb)
return;
(void) igmpv3_sendpack(skb);
}
static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
int type)
{
struct sk_buff *skb;
struct iphdr *iph;
struct igmphdr *ih;
struct rtable *rt;
struct net_device *dev = in_dev->dev;
struct net *net = dev_net(dev);
__be32 group = pmc ? pmc->multiaddr : 0;
struct flowi4 fl4;
__be32 dst;
int hlen, tlen;
if (type == IGMPV3_HOST_MEMBERSHIP_REPORT)
return igmpv3_send_report(in_dev, pmc);
if (ipv4_is_local_multicast(group) && !net->ipv4.sysctl_igmp_llm_reports)
return 0;
if (type == IGMP_HOST_LEAVE_MESSAGE)
dst = IGMP_ALL_ROUTER;
else
dst = group;
rt = ip_route_output_ports(net, &fl4, NULL, dst, 0,
0, 0,
IPPROTO_IGMP, 0, dev->ifindex);
if (IS_ERR(rt))
return -1;
hlen = LL_RESERVED_SPACE(dev);
tlen = dev->needed_tailroom;
skb = alloc_skb(IGMP_SIZE + hlen + tlen, GFP_ATOMIC);
if (!skb) {
ip_rt_put(rt);
return -1;
}
skb->priority = TC_PRIO_CONTROL;
skb_dst_set(skb, &rt->dst);
skb_reserve(skb, hlen);
skb_reset_network_header(skb);
iph = ip_hdr(skb);
skb_put(skb, sizeof(struct iphdr) + 4);
iph->version = 4;
iph->ihl = (sizeof(struct iphdr)+4)>>2;
iph->tos = 0xc0;
iph->frag_off = htons(IP_DF);
iph->ttl = 1;
iph->daddr = dst;
iph->saddr = fl4.saddr;
iph->protocol = IPPROTO_IGMP;
ip_select_ident(net, skb, NULL);
((u8 *)&iph[1])[0] = IPOPT_RA;
((u8 *)&iph[1])[1] = 4;
((u8 *)&iph[1])[2] = 0;
((u8 *)&iph[1])[3] = 0;
ih = skb_put(skb, sizeof(struct igmphdr));
ih->type = type;
ih->code = 0;
ih->csum = 0;
ih->group = group;
ih->csum = ip_compute_csum((void *)ih, sizeof(struct igmphdr));
return ip_local_out(net, skb->sk, skb);
}
static void igmp_gq_timer_expire(struct timer_list *t)
{
struct in_device *in_dev = from_timer(in_dev, t, mr_gq_timer);
in_dev->mr_gq_running = 0;
igmpv3_send_report(in_dev, NULL);
in_dev_put(in_dev);
}
static void igmp_ifc_timer_expire(struct timer_list *t)
{
struct in_device *in_dev = from_timer(in_dev, t, mr_ifc_timer);
u32 mr_ifc_count;
igmpv3_send_cr(in_dev);
restart:
mr_ifc_count = READ_ONCE(in_dev->mr_ifc_count);
if (mr_ifc_count) {
if (cmpxchg(&in_dev->mr_ifc_count,
mr_ifc_count,
mr_ifc_count - 1) != mr_ifc_count)
goto restart;
igmp_ifc_start_timer(in_dev,
unsolicited_report_interval(in_dev));
}
in_dev_put(in_dev);
}
static void igmp_ifc_event(struct in_device *in_dev)
{
struct net *net = dev_net(in_dev->dev);
if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev))
return;
WRITE_ONCE(in_dev->mr_ifc_count, in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv);
igmp_ifc_start_timer(in_dev, 1);
}
static void igmp_timer_expire(struct timer_list *t)
{
struct ip_mc_list *im = from_timer(im, t, timer);
struct in_device *in_dev = im->interface;
spin_lock(&im->lock);
im->tm_running = 0;
if (im->unsolicit_count && --im->unsolicit_count)
igmp_start_timer(im, unsolicited_report_interval(in_dev));
im->reporter = 1;
spin_unlock(&im->lock);
if (IGMP_V1_SEEN(in_dev))
igmp_send_report(in_dev, im, IGMP_HOST_MEMBERSHIP_REPORT);
else if (IGMP_V2_SEEN(in_dev))
igmp_send_report(in_dev, im, IGMPV2_HOST_MEMBERSHIP_REPORT);
else
igmp_send_report(in_dev, im, IGMPV3_HOST_MEMBERSHIP_REPORT);
ip_ma_put(im);
}
/* mark EXCLUDE-mode sources */
static int igmp_xmarksources(struct ip_mc_list *pmc, int nsrcs, __be32 *srcs)
{
struct ip_sf_list *psf;
int i, scount;
scount = 0;
for (psf = pmc->sources; psf; psf = psf->sf_next) {
if (scount == nsrcs)
break;
for (i = 0; i < nsrcs; i++) {
/* skip inactive filters */
if (psf->sf_count[MCAST_INCLUDE] ||
pmc->sfcount[MCAST_EXCLUDE] !=
psf->sf_count[MCAST_EXCLUDE])
break;
if (srcs[i] == psf->sf_inaddr) {
scount++;
break;
}
}
}
pmc->gsquery = 0;
if (scount == nsrcs) /* all sources excluded */
return 0;
return 1;
}
static int igmp_marksources(struct ip_mc_list *pmc, int nsrcs, __be32 *srcs)
{
struct ip_sf_list *psf;
int i, scount;
if (pmc->sfmode == MCAST_EXCLUDE)
return igmp_xmarksources(pmc, nsrcs, srcs);
/* mark INCLUDE-mode sources */
scount = 0;
for (psf = pmc->sources; psf; psf = psf->sf_next) {
if (scount == nsrcs)
break;
for (i = 0; i < nsrcs; i++)
if (srcs[i] == psf->sf_inaddr) {
psf->sf_gsresp = 1;
scount++;
break;
}
}
if (!scount) {
pmc->gsquery = 0;
return 0;
}
pmc->gsquery = 1;
return 1;
}
/* return true if packet was dropped */
static bool igmp_heard_report(struct in_device *in_dev, __be32 group)
{
struct ip_mc_list *im;
struct net *net = dev_net(in_dev->dev);
/* Timers are only set for non-local groups */
if (group == IGMP_ALL_HOSTS)
return false;
if (ipv4_is_local_multicast(group) && !net->ipv4.sysctl_igmp_llm_reports)
return false;
rcu_read_lock();
for_each_pmc_rcu(in_dev, im) {
if (im->multiaddr == group) {
igmp_stop_timer(im);
break;
}
}
rcu_read_unlock();
return false;
}
/* return true if packet was dropped */
static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,
int len)
{
struct igmphdr *ih = igmp_hdr(skb);
struct igmpv3_query *ih3 = igmpv3_query_hdr(skb);
struct ip_mc_list *im;
__be32 group = ih->group;
int max_delay;
int mark = 0;
struct net *net = dev_net(in_dev->dev);
if (len == 8) {
if (ih->code == 0) {
/* Alas, old v1 router presents here. */
max_delay = IGMP_QUERY_RESPONSE_INTERVAL;
in_dev->mr_v1_seen = jiffies +
(in_dev->mr_qrv * in_dev->mr_qi) +
in_dev->mr_qri;
group = 0;
} else {
/* v2 router present */
max_delay = ih->code*(HZ/IGMP_TIMER_SCALE);
in_dev->mr_v2_seen = jiffies +
(in_dev->mr_qrv * in_dev->mr_qi) +
in_dev->mr_qri;
}
/* cancel the interface change timer */
WRITE_ONCE(in_dev->mr_ifc_count, 0);
if (del_timer(&in_dev->mr_ifc_timer))
__in_dev_put(in_dev);
/* clear deleted report items */
igmpv3_clear_delrec(in_dev);
} else if (len < 12) {
return true; /* ignore bogus packet; freed by caller */
} else if (IGMP_V1_SEEN(in_dev)) {
/* This is a v3 query with v1 queriers present */
max_delay = IGMP_QUERY_RESPONSE_INTERVAL;
group = 0;
} else if (IGMP_V2_SEEN(in_dev)) {
/* this is a v3 query with v2 queriers present;
* Interpretation of the max_delay code is problematic here.
* A real v2 host would use ih_code directly, while v3 has a
* different encoding. We use the v3 encoding as more likely
* to be intended in a v3 query.
*/
max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE);
if (!max_delay)
max_delay = 1; /* can't mod w/ 0 */
} else { /* v3 */
if (!pskb_may_pull(skb, sizeof(struct igmpv3_query)))
return true;
ih3 = igmpv3_query_hdr(skb);
if (ih3->nsrcs) {
if (!pskb_may_pull(skb, sizeof(struct igmpv3_query)
+ ntohs(ih3->nsrcs)*sizeof(__be32)))
return true;
ih3 = igmpv3_query_hdr(skb);
}
max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE);