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/*
* Eric Biederman wrote this code originally.
*
*/
#include "ip.h"
#include "igmp.h"
#include "background.h"
#include "nic.h"
#include "etherboot.h"
static unsigned long last_igmpv1 = 0;
static struct igmptable_t igmptable[MAX_IGMP];
static long rfc1112_sleep_interval ( long base, int exp ) {
unsigned long divisor, tmo;
if ( exp > BACKOFF_LIMIT )
exp = BACKOFF_LIMIT;
divisor = RAND_MAX / ( base << exp );
tmo = random() / divisor;
return tmo;
}
static void send_igmp_reports ( unsigned long now ) {
struct igmp_ip_t igmp;
int i;
for ( i = 0 ; i < MAX_IGMP ; i++ ) {
if ( ! igmptable[i].time )
continue;
if ( now < igmptable[i].time )
continue;
igmp.router_alert[0] = 0x94;
igmp.router_alert[1] = 0x04;
igmp.router_alert[2] = 0;
igmp.router_alert[3] = 0;
build_ip_hdr ( igmptable[i].group.s_addr, 1, IP_IGMP,
sizeof ( igmp.router_alert ),
sizeof ( igmp ), &igmp );
igmp.igmp.type = IGMPv2_REPORT;
if ( last_igmpv1 &&
( now < last_igmpv1 + IGMPv1_ROUTER_PRESENT_TIMEOUT ) ) {
igmp.igmp.type = IGMPv1_REPORT;
}
igmp.igmp.response_time = 0;
igmp.igmp.chksum = 0;
igmp.igmp.group.s_addr = igmptable[i].group.s_addr;
igmp.igmp.chksum = ipchksum ( &igmp.igmp,
sizeof ( igmp.igmp ) );
ip_transmit ( sizeof ( igmp ), &igmp );
DBG ( "IGMP sent report to %@\n",
igmp.igmp.group.s_addr );
/* Don't send another igmp report until asked */
igmptable[i].time = 0;
}
}
static void process_igmp ( unsigned long now, unsigned short ptype __unused,
struct iphdr *ip ) {
struct igmp *igmp;
int i;
unsigned iplen;
if ( ( ! ip ) || ( ip->protocol != IP_IGMP ) ||
( nic.packetlen < ( sizeof ( struct iphdr ) +
sizeof ( struct igmp ) ) ) ) {
return;
}
iplen = ( ip->verhdrlen & 0xf ) * 4;
igmp = ( struct igmp * ) &nic.packet[ sizeof( struct iphdr ) ];
if ( ipchksum ( igmp, ntohs ( ip->len ) - iplen ) != 0 )
return;
if ( ( igmp->type == IGMP_QUERY ) &&
( ip->dest.s_addr == htonl ( GROUP_ALL_HOSTS ) ) ) {
unsigned long interval = IGMP_INTERVAL;
if ( igmp->response_time == 0 ) {
last_igmpv1 = now;
} else {
interval = ( igmp->response_time * TICKS_PER_SEC ) /10;
}
DBG ( "IGMP received query for %@\n", igmp->group.s_addr );
for ( i = 0 ; i < MAX_IGMP ; i++ ) {
uint32_t group = igmptable[i].group.s_addr;
if ( ( group == 0 ) ||
( group == igmp->group.s_addr ) ) {
unsigned long time;
time = currticks() +
rfc1112_sleep_interval ( interval, 0 );
if ( time < igmptable[i].time ) {
igmptable[i].time = time;
}
}
}
}
if ( ( ( igmp->type == IGMPv1_REPORT ) ||
( igmp->type == IGMPv2_REPORT ) ) &&
( ip->dest.s_addr == igmp->group.s_addr ) ) {
DBG ( "IGMP received report for %@\n", igmp->group.s_addr);
for ( i = 0 ; i < MAX_IGMP ; i++ ) {
if ( ( igmptable[i].group.s_addr ==
igmp->group.s_addr ) &&
( igmptable[i].time != 0 ) ) {
igmptable[i].time = 0;
}
}
}
}
static struct background igmp_background __background = {
.send = send_igmp_reports,
.process = process_igmp,
};
void leave_group ( int slot ) {
/* Be very stupid and always send a leave group message if
* I have subscribed. Imperfect but it is standards
* compliant, easy and reliable to implement.
*
* The optimal group leave method is to only send leave when,
* we were the last host to respond to a query on this group,
* and igmpv1 compatibility is not enabled.
*/
if ( igmptable[slot].group.s_addr ) {
struct igmp_ip_t igmp;
igmp.router_alert[0] = 0x94;
igmp.router_alert[1] = 0x04;
igmp.router_alert[2] = 0;
igmp.router_alert[3] = 0;
build_ip_hdr ( htonl ( GROUP_ALL_HOSTS ), 1, IP_IGMP,
sizeof ( igmp.router_alert ), sizeof ( igmp ),
&igmp);
igmp.igmp.type = IGMP_LEAVE;
igmp.igmp.response_time = 0;
igmp.igmp.chksum = 0;
igmp.igmp.group.s_addr = igmptable[slot].group.s_addr;
igmp.igmp.chksum = ipchksum ( &igmp.igmp, sizeof ( igmp ) );
ip_transmit ( sizeof ( igmp ), &igmp );
DBG ( "IGMP left group %@\n", igmp.igmp.group.s_addr );
}
memset ( &igmptable[slot], 0, sizeof ( igmptable[0] ) );
}
void join_group ( int slot, unsigned long group ) {
/* I have already joined */
if ( igmptable[slot].group.s_addr == group )
return;
if ( igmptable[slot].group.s_addr ) {
leave_group ( slot );
}
/* Only join a group if we are given a multicast ip, this way
* code can be given a non-multicast (broadcast or unicast ip)
* and still work...
*/
if ( ( group & htonl ( MULTICAST_MASK ) ) ==
htonl ( MULTICAST_NETWORK ) ) {
igmptable[slot].group.s_addr = group;
igmptable[slot].time = currticks();
}
}
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