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/*
* 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.
*
* Version: $Id: igmp.c,v 1.46 2001/07/27 09:27:29 davem Exp $
*
* Authors:
* Alan Cox <Alan.Cox@linux.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* 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.
*/
#include <linux/config.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.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 <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/sock.h>
#include <net/checksum.h>
#include <linux/netfilter_ipv4.h>
#ifdef CONFIG_IP_MROUTE
#include <linux/mroute.h>
#endif
#define IP_MAX_MEMBERSHIPS 20
#ifdef CONFIG_IP_MULTICAST
/* Parameter names and values are taken from igmp-v2-06 draft */
#define IGMP_V1_Router_Present_Timeout (400*HZ)
#define IGMP_Unsolicited_Report_Interval (10*HZ)
#define IGMP_Query_Response_Interval (10*HZ)
#define IGMP_Unsolicited_Report_Count 2
#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) ((in_dev)->mr_v1_seen && (long)(jiffies - (in_dev)->mr_v1_seen) < 0)
#endif
static void ip_ma_put(struct ip_mc_list *im)
{
if (atomic_dec_and_test(&im->refcnt)) {
in_dev_put(im->interface);
kfree(im);
}
}
#ifdef CONFIG_IP_MULTICAST
/*
* Timer management
*/
static __inline__ void igmp_stop_timer(struct ip_mc_list *im)
{
spin_lock_bh(&im->lock);
if (del_timer(&im->timer))
atomic_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=net_random() % max_delay;
im->tm_running=1;
if (!mod_timer(&im->timer, jiffies+tv+2))
atomic_inc(&im->refcnt);
}
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;
}
atomic_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)
/* Don't just hand NF_HOOK skb->dst->output, in case netfilter hook
changes route */
static inline int
output_maybe_reroute(struct sk_buff *skb)
{
return skb->dst->output(skb);
}
static int igmp_send_report(struct net_device *dev, u32 group, int type)
{
struct sk_buff *skb;
struct iphdr *iph;
struct igmphdr *ih;
struct rtable *rt;
u32 dst;
/* According to IGMPv2 specs, LEAVE messages are
* sent to all-routers group.
*/
dst = group;
if (type == IGMP_HOST_LEAVE_MESSAGE)
dst = IGMP_ALL_ROUTER;
if (ip_route_output(&rt, dst, 0, 0, dev->ifindex))
return -1;
if (rt->rt_src == 0) {
ip_rt_put(rt);
return -1;
}
skb=alloc_skb(IGMP_SIZE+dev->hard_header_len+15, GFP_ATOMIC);
if (skb == NULL) {
ip_rt_put(rt);
return -1;
}
skb->dst = &rt->u.dst;
skb_reserve(skb, (dev->hard_header_len+15)&~15);
skb->nh.iph = iph = (struct iphdr *)skb_put(skb, sizeof(struct iphdr)+4);
iph->version = 4;
iph->ihl = (sizeof(struct iphdr)+4)>>2;
iph->tos = 0;
iph->frag_off = __constant_htons(IP_DF);
iph->ttl = 1;
iph->daddr = dst;
iph->saddr = rt->rt_src;
iph->protocol = IPPROTO_IGMP;
iph->tot_len = htons(IGMP_SIZE);
ip_select_ident(iph, &rt->u.dst, NULL);
((u8*)&iph[1])[0] = IPOPT_RA;
((u8*)&iph[1])[1] = 4;
((u8*)&iph[1])[2] = 0;
((u8*)&iph[1])[3] = 0;
ip_send_check(iph);
ih = (struct igmphdr *)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 NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev,
output_maybe_reroute);
}
static void igmp_timer_expire(unsigned long data)
{
struct ip_mc_list *im=(struct ip_mc_list *)data;
struct in_device *in_dev = im->interface;
int err;
spin_lock(&im->lock);
im->tm_running=0;
if (IGMP_V1_SEEN(in_dev))
err = igmp_send_report(in_dev->dev, im->multiaddr, IGMP_HOST_MEMBERSHIP_REPORT);
else
err = igmp_send_report(in_dev->dev, im->multiaddr, IGMP_HOST_NEW_MEMBERSHIP_REPORT);
/* Failed. Retry later. */
if (err) {
if (!in_dev->dead)
igmp_start_timer(im, IGMP_Unsolicited_Report_Interval);
goto out;
}
if (im->unsolicit_count) {
im->unsolicit_count--;
igmp_start_timer(im, IGMP_Unsolicited_Report_Interval);
}
im->reporter = 1;
out:
spin_unlock(&im->lock);
ip_ma_put(im);
}
static void igmp_heard_report(struct in_device *in_dev, u32 group)
{
struct ip_mc_list *im;
/* Timers are only set for non-local groups */
if (group == IGMP_ALL_HOSTS)
return;
read_lock(&in_dev->lock);
for (im=in_dev->mc_list; im!=NULL; im=im->next) {
if (im->multiaddr == group) {
igmp_stop_timer(im);
break;
}
}
read_unlock(&in_dev->lock);
}
static void igmp_heard_query(struct in_device *in_dev, unsigned char max_resp_time,
u32 group)
{
struct ip_mc_list *im;
int max_delay;
max_delay = max_resp_time*(HZ/IGMP_TIMER_SCALE);
if (max_resp_time == 0) {
/* Alas, old v1 router presents here. */
max_delay = IGMP_Query_Response_Interval;
in_dev->mr_v1_seen = jiffies + IGMP_V1_Router_Present_Timeout;
group = 0;
}
/*
* - 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 a "local" group (224.0.0.X)
* - For timers already running check if they need to
* be reset.
* - Use the igmp->igmp_code field as the maximum
* delay possible
*/
read_lock(&in_dev->lock);
for (im=in_dev->mc_list; im!=NULL; im=im->next) {
if (group && group != im->multiaddr)
continue;
if (im->multiaddr == IGMP_ALL_HOSTS)
continue;
igmp_mod_timer(im, max_delay);
}
read_unlock(&in_dev->lock);
}
int igmp_rcv(struct sk_buff *skb)
{
/* This basically follows the spec line by line -- see RFC1112 */
struct igmphdr *ih = skb->h.igmph;
struct in_device *in_dev = in_dev_get(skb->dev);
int len = skb->len;
if (in_dev==NULL) {
kfree_skb(skb);
return 0;
}
if (skb_is_nonlinear(skb)) {
if (skb_linearize(skb, GFP_ATOMIC) != 0) {
kfree_skb(skb);
return -ENOMEM;
}
ih = skb->h.igmph;
}
if (len < sizeof(struct igmphdr) || ip_compute_csum((void *)ih, len)) {
in_dev_put(in_dev);
kfree_skb(skb);
return 0;
}
switch (ih->type) {
case IGMP_HOST_MEMBERSHIP_QUERY:
igmp_heard_query(in_dev, ih->code, ih->group);
break;
case IGMP_HOST_MEMBERSHIP_REPORT:
case IGMP_HOST_NEW_MEMBERSHIP_REPORT:
/* Is it our report looped back? */
if (((struct rtable*)skb->dst)->key.iif == 0)
break;
igmp_heard_report(in_dev, ih->group);
break;
case IGMP_PIM:
#ifdef CONFIG_IP_PIMSM_V1
in_dev_put(in_dev);
return pim_rcv_v1(skb);
#endif
case IGMP_DVMRP:
case IGMP_TRACE:
case IGMP_HOST_LEAVE_MESSAGE:
case IGMP_MTRACE:
case IGMP_MTRACE_RESP:
break;
default:
NETDEBUG(printk(KERN_DEBUG "New IGMP type=%d, why we do not know about it?\n", ih->type));
}
in_dev_put(in_dev);
kfree_skb(skb);
return 0;
}
#endif
/*
* Add a filter to a device
*/
static void ip_mc_filter_add(struct in_device *in_dev, u32 addr)
{
char buf[MAX_ADDR_LEN];
struct net_device *dev = in_dev->dev;
/* Checking for IFF_MULTICAST here is WRONG-WRONG-WRONG.
We will get multicast token leakage, when IFF_MULTICAST
is changed. This check should be done in dev->set_multicast_list
routine. Something sort of:
if (dev->mc_list && dev->flags&IFF_MULTICAST) { do it; }
--ANK
*/
if (arp_mc_map(addr, buf, dev, 0) == 0)
dev_mc_add(dev,buf,dev->addr_len,0);
}
/*
* Remove a filter from a device
*/
static void ip_mc_filter_del(struct in_device *in_dev, u32 addr)
{
char buf[MAX_ADDR_LEN];
struct net_device *dev = in_dev->dev;
if (arp_mc_map(addr, buf, dev, 0) == 0)
dev_mc_delete(dev,buf,dev->addr_len,0);
}
static void igmp_group_dropped(struct ip_mc_list *im)
{
#ifdef CONFIG_IP_MULTICAST
int reporter;
#endif
if (im->loaded) {
im->loaded = 0;
ip_mc_filter_del(im->interface, im->multiaddr);
}
#ifdef CONFIG_IP_MULTICAST
if (im->multiaddr == IGMP_ALL_HOSTS)
return;
reporter = im->reporter;
igmp_stop_timer(im);
if (reporter && !IGMP_V1_SEEN(im->interface))
igmp_send_report(im->interface->dev, im->multiaddr, IGMP_HOST_LEAVE_MESSAGE);
#endif
}
static void igmp_group_added(struct ip_mc_list *im)
{
if (im->loaded == 0) {
im->loaded = 1;
ip_mc_filter_add(im->interface, im->multiaddr);
}
#ifdef CONFIG_IP_MULTICAST
if (im->multiaddr == IGMP_ALL_HOSTS)
return;
spin_lock_bh(&im->lock);
igmp_start_timer(im, IGMP_Initial_Report_Delay);
spin_unlock_bh(&im->lock);
#endif
}
/*
* Multicast list managers
*/
/*
* A socket has joined a multicast group on device dev.
*/
void ip_mc_inc_group(struct in_device *in_dev, u32 addr)
{
struct ip_mc_list *im;
ASSERT_RTNL();
for (im=in_dev->mc_list; im; im=im->next) {
if (im->multiaddr == addr) {
im->users++;
goto out;
}
}
im = (struct ip_mc_list *)kmalloc(sizeof(*im), GFP_KERNEL);
if (!im)
goto out;
im->users=1;
im->interface=in_dev;
in_dev_hold(in_dev);
im->multiaddr=addr;
atomic_set(&im->refcnt, 1);
spin_lock_init(&im->lock);
#ifdef CONFIG_IP_MULTICAST
im->tm_running=0;
init_timer(&im->timer);
im->timer.data=(unsigned long)im;
im->timer.function=&igmp_timer_expire;
im->unsolicit_count = IGMP_Unsolicited_Report_Count;
im->reporter = 0;
#endif
im->loaded = 0;
write_lock_bh(&in_dev->lock);
im->next=in_dev->mc_list;
in_dev->mc_list=im;
write_unlock_bh(&in_dev->lock);
igmp_group_added(im);
if (in_dev->dev->flags & IFF_UP)
ip_rt_multicast_event(in_dev);
out:
return;
}
/*
* A socket has left a multicast group on device dev
*/
int ip_mc_dec_group(struct in_device *in_dev, u32 addr)
{
int err = -ESRCH;
struct ip_mc_list *i, **ip;
ASSERT_RTNL();
for (ip=&in_dev->mc_list; (i=*ip)!=NULL; ip=&i->next) {
if (i->multiaddr==addr) {
if (--i->users == 0) {
write_lock_bh(&in_dev->lock);
*ip = i->next;
write_unlock_bh(&in_dev->lock);
igmp_group_dropped(i);
if (in_dev->dev->flags & IFF_UP)
ip_rt_multicast_event(in_dev);
ip_ma_put(i);
return 0;
}
err = 0;
break;
}
}
return -ESRCH;
}
/* Device going down */
void ip_mc_down(struct in_device *in_dev)
{
struct ip_mc_list *i;
ASSERT_RTNL();
for (i=in_dev->mc_list; i; i=i->next)
igmp_group_dropped(i);
ip_mc_dec_group(in_dev, IGMP_ALL_HOSTS);
}
/* Device going up */
void ip_mc_up(struct in_device *in_dev)
{
struct ip_mc_list *i;
ASSERT_RTNL();
ip_mc_inc_group(in_dev, IGMP_ALL_HOSTS);
for (i=in_dev->mc_list; i; i=i->next)
igmp_group_added(i);
}
/*
* Device is about to be destroyed: clean up.
*/
void ip_mc_destroy_dev(struct in_device *in_dev)
{
struct ip_mc_list *i;
ASSERT_RTNL();
write_lock_bh(&in_dev->lock);
while ((i = in_dev->mc_list) != NULL) {
in_dev->mc_list = i->next;
write_unlock_bh(&in_dev->lock);
igmp_group_dropped(i);
ip_ma_put(i);
write_lock_bh(&in_dev->lock);
}
write_unlock_bh(&in_dev->lock);
}
static struct in_device * ip_mc_find_dev(struct ip_mreqn *imr)
{
struct rtable *rt;
struct net_device *dev = NULL;
struct in_device *idev = NULL;
if (imr->imr_address.s_addr) {
dev = ip_dev_find(imr->imr_address.s_addr);
if (!dev)
return NULL;
__dev_put(dev);
}
if (!dev && !ip_route_output(&rt, imr->imr_multiaddr.s_addr, 0, 0, 0)) {
dev = rt->u.dst.dev;
ip_rt_put(rt);
}
if (dev) {
imr->imr_ifindex = dev->ifindex;
idev = __in_dev_get(dev);
}
return idev;
}
/*
* Join a socket to a group
*/
int sysctl_igmp_max_memberships = IP_MAX_MEMBERSHIPS;
int ip_mc_join_group(struct sock *sk , struct ip_mreqn *imr)
{
int err;
u32 addr = imr->imr_multiaddr.s_addr;
struct ip_mc_socklist *iml, *i;
struct in_device *in_dev;
int count = 0;
if (!MULTICAST(addr))
return -EINVAL;
rtnl_shlock();
if (!imr->imr_ifindex)
in_dev = ip_mc_find_dev(imr);
else {
in_dev = inetdev_by_index(imr->imr_ifindex);
if (in_dev)
__in_dev_put(in_dev);
}
if (!in_dev) {
iml = NULL;
err = -ENODEV;
goto done;
}
iml = (struct ip_mc_socklist *)sock_kmalloc(sk, sizeof(*iml), GFP_KERNEL);
err = -EADDRINUSE;
for (i=sk->protinfo.af_inet.mc_list; i; i=i->next) {
if (memcmp(&i->multi, imr, sizeof(*imr)) == 0) {
/* New style additions are reference counted */
if (imr->imr_address.s_addr == 0) {
i->count++;
err = 0;
}
goto done;
}
count++;
}
err = -ENOBUFS;
if (iml == NULL || count >= sysctl_igmp_max_memberships)
goto done;
memcpy(&iml->multi, imr, sizeof(*imr));
iml->next = sk->protinfo.af_inet.mc_list;
iml->count = 1;
sk->protinfo.af_inet.mc_list = iml;
ip_mc_inc_group(in_dev, addr);
iml = NULL;
err = 0;
done:
rtnl_shunlock();
if (iml)
sock_kfree_s(sk, iml, sizeof(*iml));
return err;
}
/*
* Ask a socket to leave a group.
*/
int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr)
{
struct ip_mc_socklist *iml, **imlp;
rtnl_lock();
for (imlp=&sk->protinfo.af_inet.mc_list; (iml=*imlp)!=NULL; imlp=&iml->next) {
if (iml->multi.imr_multiaddr.s_addr==imr->imr_multiaddr.s_addr &&
iml->multi.imr_address.s_addr==imr->imr_address.s_addr &&
(!imr->imr_ifindex || iml->multi.imr_ifindex==imr->imr_ifindex)) {
struct in_device *in_dev;
if (--iml->count) {
rtnl_unlock();
return 0;
}
*imlp = iml->next;
in_dev = inetdev_by_index(iml->multi.imr_ifindex);
if (in_dev) {
ip_mc_dec_group(in_dev, imr->imr_multiaddr.s_addr);
in_dev_put(in_dev);
}
rtnl_unlock();
sock_kfree_s(sk, iml, sizeof(*iml));
return 0;
}
}
rtnl_unlock();
return -EADDRNOTAVAIL;
}
/*
* A socket is closing.
*/
void ip_mc_drop_socket(struct sock *sk)
{
struct ip_mc_socklist *iml;
if (sk->protinfo.af_inet.mc_list == NULL)
return;
rtnl_lock();
while ((iml=sk->protinfo.af_inet.mc_list) != NULL) {
struct in_device *in_dev;
sk->protinfo.af_inet.mc_list = iml->next;
if ((in_dev = inetdev_by_index(iml->multi.imr_ifindex)) != NULL) {
ip_mc_dec_group(in_dev, iml->multi.imr_multiaddr.s_addr);
in_dev_put(in_dev);
}
sock_kfree_s(sk, iml, sizeof(*iml));
}
rtnl_unlock();
}
int ip_check_mc(struct in_device *in_dev, u32 mc_addr)
{
struct ip_mc_list *im;
read_lock(&in_dev->lock);
for (im=in_dev->mc_list; im; im=im->next) {
if (im->multiaddr == mc_addr) {
read_unlock(&in_dev->lock);
return 1;
}
}
read_unlock(&in_dev->lock);
return 0;
}
#ifdef CONFIG_IP_MULTICAST
int ip_mc_procinfo(char *buffer, char **start, off_t offset, int length)
{
off_t pos=0, begin=0;
struct ip_mc_list *im;
int len=0;
struct net_device *dev;
len=sprintf(buffer,"Idx\tDevice : Count Querier\tGroup Users Timer\tReporter\n");
read_lock(&dev_base_lock);
for(dev = dev_base; dev; dev = dev->next) {
struct in_device *in_dev = in_dev_get(dev);
char *querier = "NONE";
if (in_dev == NULL)
continue;
querier = IGMP_V1_SEEN(in_dev) ? "V1" : "V2";
len+=sprintf(buffer+len,"%d\t%-10s: %5d %7s\n",
dev->ifindex, dev->name, dev->mc_count, querier);
read_lock(&in_dev->lock);
for (im = in_dev->mc_list; im; im = im->next) {
len+=sprintf(buffer+len,
"\t\t\t\t%08lX %5d %d:%08lX\t\t%d\n",
im->multiaddr, im->users,
im->tm_running, im->timer.expires-jiffies, im->reporter);
pos=begin+len;
if(pos<offset)
{
len=0;
begin=pos;
}
if(pos>offset+length) {
read_unlock(&in_dev->lock);
in_dev_put(in_dev);
goto done;
}
}
read_unlock(&in_dev->lock);
in_dev_put(in_dev);
}
done:
read_unlock(&dev_base_lock);
*start=buffer+(offset-begin);
len-=(offset-begin);
if(len>length)
len=length;
if(len<0)
len=0;
return len;
}
#endif
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