/*
* 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.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.
*/
#include <asm/segment.h>
#include <asm/system.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/config.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/igmp.h>
#include <net/checksum.h>
#ifdef CONFIG_IP_MULTICAST
/*
* If time expired, change the router type to IGMP_NEW_ROUTER.
*/
static void ip_router_timer_expire(unsigned long data)
{
struct ip_router_info *i=(struct ip_router_info *)data;
del_timer(&i->timer);
i->type=IGMP_NEW_ROUTER; /* Revert to new multicast router */
i->time=0;
}
/*
* Multicast router info manager
*/
struct ip_router_info *ip_router_info_head=(struct ip_router_info *)0;
/*
* Get the multicast router info on that device
*/
static struct ip_router_info *igmp_get_mrouter_info(struct device *dev)
{
register struct ip_router_info *i;
for(i=ip_router_info_head;i!=NULL;i=i->next)
{
if (i->dev == dev)
{
return i;
}
}
/*
* Not found. Create a new entry. The default is IGMP V2 router
*/
i=(struct ip_router_info *)kmalloc(sizeof(*i), GFP_ATOMIC);
if(i==NULL)
return NULL;
i->dev = dev;
i->type = IGMP_NEW_ROUTER;
i->time = IGMP_AGE_THRESHOLD;
i->next = ip_router_info_head;
ip_router_info_head = i;
init_timer(&i->timer);
i->timer.data=(unsigned long)i;
i->timer.function=&ip_router_timer_expire;
return i;
}
/*
* Set the multicast router info on that device
*/
static struct ip_router_info *igmp_set_mrouter_info(struct device *dev,int type,int time)
{
register struct ip_router_info *i;
for(i=ip_router_info_head;i!=NULL;i=i->next)
{
if (i->dev == dev)
{
if(i->type==IGMP_OLD_ROUTER)
{
del_timer(&i->timer);
}
i->type = type;
i->time = time;
if(i->type==IGMP_OLD_ROUTER)
{
i->timer.expires=jiffies+i->time*HZ;
add_timer(&i->timer);
}
return i;
}
}
/*
* Not found. Create a new entry.
*/
i=(struct ip_router_info *)kmalloc(sizeof(*i), GFP_ATOMIC);
if(i==NULL)
return NULL;
i->dev = dev;
i->type = type;
i->time = time;
i->next = ip_router_info_head;
ip_router_info_head = i;
init_timer(&i->timer);
i->timer.data=(unsigned long)i;
i->timer.function=&ip_router_timer_expire;
if(i->type==IGMP_OLD_ROUTER)
{
i->timer.expires=jiffies+i->time*HZ;
add_timer(&i->timer);
}
return i;
}
/*
* Timer management
*/
static void igmp_stop_timer(struct ip_mc_list *im)
{
if (im->tm_running) {
del_timer(&im->timer);
im->tm_running=0;
}
else {
printk(KERN_ERR "igmp_stop_timer() called with timer not running by %p\n",__builtin_return_address(0));
}
}
extern __inline__ unsigned int random(void)
{
static unsigned long seed=152L;
seed=seed*69069L+1;
return seed^jiffies;
}
/*
* Inlined as it's only called once.
*/
static void igmp_start_timer(struct ip_mc_list *im,unsigned char max_resp_time)
{
int tv;
if(im->tm_running)
return;
tv=random()%(max_resp_time*HZ/IGMP_TIMER_SCALE); /* Pick a number any number 8) */
im->timer.expires=jiffies+tv;
im->tm_running=1;
add_timer(&im->timer);
}
/*
* Send an IGMP report.
*/
#define MAX_IGMP_SIZE (sizeof(struct igmphdr)+sizeof(struct iphdr)+64)
static void igmp_send_report(struct device *dev, unsigned long address, int type)
{
struct sk_buff *skb=alloc_skb(MAX_IGMP_SIZE, GFP_ATOMIC);
int tmp;
struct igmphdr *ih;
if(skb==NULL)
return;
tmp=ip_build_header(skb, dev->pa_addr, address, &dev, IPPROTO_IGMP, NULL,
28 , 0, 1, NULL);
if(tmp<0)
{
kfree_skb(skb, FREE_WRITE);
return;
}
ih=(struct igmphdr *)skb_put(skb,sizeof(struct igmphdr));
ih->type=type;
ih->code=0;
ih->csum=0;
ih->group=address;
ih->csum=ip_compute_csum((void *)ih,sizeof(struct igmphdr)); /* Checksum fill */
ip_queue_xmit(NULL,dev,skb,1);
}
static void igmp_timer_expire(unsigned long data)
{
struct ip_mc_list *im=(struct ip_mc_list *)data;
struct ip_router_info *r;
im->tm_running=0;
r=igmp_get_mrouter_info(im->interface);
if(r==NULL)
return;
if(r->type==IGMP_NEW_ROUTER)
igmp_send_report(im->interface, im->multiaddr, IGMP_HOST_NEW_MEMBERSHIP_REPORT);
else
igmp_send_report(im->interface, im->multiaddr, IGMP_HOST_MEMBERSHIP_REPORT);
im->reporter=1;
}
static void igmp_init_timer(struct ip_mc_list *im)
{
im->tm_running=0;
init_timer(&im->timer);
im->timer.data=(unsigned long)im;
im->timer.function=&igmp_timer_expire;
}
static void igmp_heard_report(struct device *dev, __u32 address, __u32 src)
{
struct ip_mc_list *im;
if ((address & IGMP_LOCAL_GROUP_MASK) != IGMP_LOCAL_GROUP)
{
/* Timers are only set for non-local groups */
for(im=dev->ip_mc_list;im!=NULL;im=im->next)
{
if(im->multiaddr==address)
{
if(im->tm_running)
igmp_stop_timer(im);
if(src!=dev->pa_addr)
im->reporter=0;
return;
}
}
}
}
static void igmp_heard_query(struct device *dev,unsigned char max_resp_time)
{
struct ip_mc_list *im;
int mrouter_type;
/*
* The max_resp_time is in units of 1/10 second.
*/
if(max_resp_time>0)
{
mrouter_type=IGMP_NEW_ROUTER;
if(igmp_set_mrouter_info(dev,mrouter_type,0)==NULL)
return;
/*
* - 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
*/
for(im=dev->ip_mc_list;im!=NULL;im=im->next)
{
if(im->tm_running)
{
if(im->timer.expires>jiffies+max_resp_time*HZ/IGMP_TIMER_SCALE)
{
igmp_stop_timer(im);
igmp_start_timer(im,max_resp_time);
}
}
else
{
if((im->multiaddr & IGMP_LOCAL_GROUP_MASK)!=IGMP_LOCAL_GROUP)
igmp_start_timer(im,max_resp_time);
}
}
}
else
{
mrouter_type=IGMP_OLD_ROUTER;
max_resp_time=IGMP_MAX_HOST_REPORT_DELAY*IGMP_TIMER_SCALE;
if(igmp_set_mrouter_info(dev,mrouter_type,IGMP_AGE_THRESHOLD)==NULL)
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).
*/
for(im=dev->ip_mc_list;im!=NULL;im=im->next)
{
if(!im->tm_running && (im->multiaddr & IGMP_LOCAL_GROUP_MASK)!=IGMP_LOCAL_GROUP)
igmp_start_timer(im,max_resp_time);
}
}
}
/*
* Map a multicast IP onto multicast MAC for type ethernet.
*/
extern __inline__ void ip_mc_map(unsigned long addr, char *buf)
{
addr=ntohl(addr);
buf[0]=0x01;
buf[1]=0x00;
buf[2]=0x5e;
buf[5]=addr&0xFF;
addr>>=8;
buf[4]=addr&0xFF;
addr>>=8;
buf[3]=addr&0x7F;
}
/*
* Add a filter to a device
*/
void ip_mc_filter_add(struct device *dev, unsigned long addr)
{
char buf[6];
if(dev->type!=ARPHRD_ETHER && dev->type!=ARPHRD_FDDI)
return; /* Only do ethernet or FDDI for now */
ip_mc_map(addr,buf);
dev_mc_add(dev,buf,ETH_ALEN,0);
}
/*
* Remove a filter from a device
*/
void ip_mc_filter_del(struct device *dev, unsigned long addr)
{
char buf[6];
if(dev->type!=ARPHRD_ETHER && dev->type!=ARPHRD_FDDI)
return; /* Only do ethernet or FDDI for now */
ip_mc_map(addr,buf);
dev_mc_delete(dev,buf,ETH_ALEN,0);
}
extern __inline__ void igmp_group_dropped(struct ip_mc_list *im)
{
del_timer(&im->timer);
igmp_send_report(im->interface, im->multiaddr, IGMP_HOST_LEAVE_MESSAGE);
ip_mc_filter_del(im->interface, im->multiaddr);
}
extern __inline__ void igmp_group_added(struct ip_mc_list *im)
{
struct ip_router_info *r;
igmp_init_timer(im);
ip_mc_filter_add(im->interface, im->multiaddr);
r=igmp_get_mrouter_info(im->interface);
if(r==NULL)
return;
if(r->type==IGMP_NEW_ROUTER)
igmp_send_report(im->interface, im->multiaddr, IGMP_HOST_NEW_MEMBERSHIP_REPORT);
else
igmp_send_report(im->interface, im->multiaddr, IGMP_HOST_MEMBERSHIP_REPORT);
}
int igmp_rcv(struct sk_buff *skb, struct device *dev, struct options *opt,
__u32 daddr, unsigned short len, __u32 saddr, int redo,
struct inet_protocol *protocol)
{
/* This basically follows the spec line by line -- see RFC1112 */
struct igmphdr *ih;
/*
* Mrouted needs to able to query local interfaces. So
* report for the device this was sent at. (Which can
* be the loopback this time)
*/
if(dev->flags&IFF_LOOPBACK)
{
dev=ip_dev_find(saddr);
if(dev==NULL)
dev=&loopback_dev;
}
ih=(struct igmphdr *)skb->h.raw;
if(len <sizeof(struct igmphdr) || skb->ip_hdr->ttl<1 || ip_compute_csum((void *)skb->h.raw,sizeof(struct igmphdr)))
{
kfree_skb(skb, FREE_READ);
return 0;
}
/*
* I have a report that someone does this!
*/
if(saddr==0)
{
printk(KERN_INFO "Broken multicast host using 0.0.0.0 heard on %s\n",
dev->name);
kfree_skb(skb, FREE_READ);
return 0;
}
if(ih->type==IGMP_HOST_MEMBERSHIP_QUERY && daddr==IGMP_ALL_HOSTS)
igmp_heard_query(dev,ih->code);
if(ih->type==IGMP_HOST_MEMBERSHIP_REPORT && daddr==ih->group)
igmp_heard_report(dev,ih->group, saddr);
if(ih->type==IGMP_HOST_NEW_MEMBERSHIP_REPORT && daddr==ih->group)
igmp_heard_report(dev,ih->group, saddr);
kfree_skb(skb, FREE_READ);
return 0;
}
/*
* Multicast list managers
*/
/*
* A socket has joined a multicast group on device dev.
*/
static void ip_mc_inc_group(struct device *dev, unsigned long addr)
{
struct ip_mc_list *i;
for(i=dev->ip_mc_list;i!=NULL;i=i->next)
{
if(i->multiaddr==addr)
{
i->users++;
return;
}
}
i=(struct ip_mc_list *)kmalloc(sizeof(*i), GFP_KERNEL);
if(!i)
return;
i->users=1;
i->interface=dev;
i->multiaddr=addr;
i->next=dev->ip_mc_list;
igmp_group_added(i);
dev->ip_mc_list=i;
}
/*
* A socket has left a multicast group on device dev
*/
static void ip_mc_dec_group(struct device *dev, unsigned long addr)
{
struct ip_mc_list **i;
for(i=&(dev->ip_mc_list);(*i)!=NULL;i=&(*i)->next)
{
if((*i)->multiaddr==addr)
{
if(--((*i)->users) == 0)
{
struct ip_mc_list *tmp= *i;
igmp_group_dropped(tmp);
*i=(*i)->next;
kfree_s(tmp,sizeof(*tmp));
}
return;
}
}
}
/*
* Device going down: Clean up.
*/
void ip_mc_drop_device(struct device *dev)
{
struct ip_mc_list *i;
struct ip_mc_list *j;
for(i=dev->ip_mc_list;i!=NULL;i=j)
{
j=i->next;
kfree_s(i,sizeof(*i));
}
dev->ip_mc_list=NULL;
}
/*
* Device going up. Make sure it is in all hosts
*/
void ip_mc_allhost(struct device *dev)
{
struct ip_mc_list *i;
for(i=dev->ip_mc_list;i!=NULL;i=i->next)
if(i->multiaddr==IGMP_ALL_HOSTS)
return;
i=(struct ip_mc_list *)kmalloc(sizeof(*i), GFP_KERNEL);
if(!i)
return;
i->users=1;
i->interface=dev;
i->multiaddr=IGMP_ALL_HOSTS;
i->tm_running=0;
i->next=dev->ip_mc_list;
dev->ip_mc_list=i;
ip_mc_filter_add(i->interface, i->multiaddr);
}
/*
* Join a socket to a group
*/
int ip_mc_join_group(struct sock *sk , struct device *dev, unsigned long addr)
{
int unused= -1;
int i;
if(!MULTICAST(addr))
return -EINVAL;
if(!(dev->flags&IFF_MULTICAST))
return -EADDRNOTAVAIL;
if(sk->ip_mc_list==NULL)
{
if((sk->ip_mc_list=(struct ip_mc_socklist *)kmalloc(sizeof(*sk->ip_mc_list), GFP_KERNEL))==NULL)
return -ENOMEM;
memset(sk->ip_mc_list,'\0',sizeof(*sk->ip_mc_list));
}
for(i=0;i<IP_MAX_MEMBERSHIPS;i++)
{
if(sk->ip_mc_list->multiaddr[i]==addr && sk->ip_mc_list->multidev[i]==dev)
return -EADDRINUSE;
if(sk->ip_mc_list->multidev[i]==NULL)
unused=i;
}
if(unused==-1)
return -ENOBUFS;
sk->ip_mc_list->multiaddr[unused]=addr;
sk->ip_mc_list->multidev[unused]=dev;
ip_mc_inc_group(dev,addr);
return 0;
}
/*
* Ask a socket to leave a group.
*/
int ip_mc_leave_group(struct sock *sk, struct device *dev, unsigned long addr)
{
int i;
if(!MULTICAST(addr))
return -EINVAL;
if(!(dev->flags&IFF_MULTICAST))
return -EADDRNOTAVAIL;
if(sk->ip_mc_list==NULL)
return -EADDRNOTAVAIL;
for(i=0;i<IP_MAX_MEMBERSHIPS;i++)
{
if(sk->ip_mc_list->multiaddr[i]==addr && sk->ip_mc_list->multidev[i]==dev)
{
sk->ip_mc_list->multidev[i]=NULL;
ip_mc_dec_group(dev,addr);
return 0;
}
}
return -EADDRNOTAVAIL;
}
/*
* A socket is closing.
*/
void ip_mc_drop_socket(struct sock *sk)
{
int i;
if(sk->ip_mc_list==NULL)
return;
for(i=0;i<IP_MAX_MEMBERSHIPS;i++)
{
if(sk->ip_mc_list->multidev[i])
{
ip_mc_dec_group(sk->ip_mc_list->multidev[i], sk->ip_mc_list->multiaddr[i]);
sk->ip_mc_list->multidev[i]=NULL;
}
}
kfree_s(sk->ip_mc_list,sizeof(*sk->ip_mc_list));
sk->ip_mc_list=NULL;
}
#endif
