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IGMP functions separated out from nic.c
This commit is contained in:
Michael Brown
parent
698e87277f
commit
e0cf144218
160
src/proto/igmp.c
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160
src/proto/igmp.c
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/*
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* Eric Biederman wrote this code originally.
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*
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*/
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#include "ip.h"
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#include "igmp.h"
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#include "nic.h"
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#include "etherboot.h"
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static unsigned long last_igmpv1 = 0;
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static struct igmptable_t igmptable[MAX_IGMP];
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static long rfc1112_sleep_interval ( long base, int exp ) {
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unsigned long divisor, tmo;
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if ( exp > BACKOFF_LIMIT )
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exp = BACKOFF_LIMIT;
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divisor = RAND_MAX / ( base << exp );
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tmo = random() / divisor;
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return tmo;
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}
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static void send_igmp_reports ( unsigned long now ) {
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struct igmp_ip_t igmp;
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int i;
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for ( i = 0 ; i < MAX_IGMP ; i++ ) {
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if ( ! igmptable[i].time )
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continue;
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if ( now < igmptable[i].time )
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continue;
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igmp.router_alert[0] = 0x94;
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igmp.router_alert[1] = 0x04;
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igmp.router_alert[2] = 0;
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igmp.router_alert[3] = 0;
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build_ip_hdr ( igmptable[i].group.s_addr, 1, IP_IGMP,
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sizeof ( igmp.router_alert ),
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sizeof ( igmp ), &igmp );
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igmp.igmp.type = IGMPv2_REPORT;
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if ( last_igmpv1 &&
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( now < last_igmpv1 + IGMPv1_ROUTER_PRESENT_TIMEOUT ) ) {
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igmp.igmp.type = IGMPv1_REPORT;
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}
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igmp.igmp.response_time = 0;
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igmp.igmp.chksum = 0;
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igmp.igmp.group.s_addr = igmptable[i].group.s_addr;
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igmp.igmp.chksum = ipchksum ( &igmp.igmp,
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sizeof ( igmp.igmp ) );
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ip_transmit ( sizeof ( igmp ), &igmp );
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DBG ( "IGMP sent report to %@\n",
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igmp.igmp.group.s_addr );
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/* Don't send another igmp report until asked */
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igmptable[i].time = 0;
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}
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}
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static void process_igmp ( struct iphdr *ip, unsigned long now ) {
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struct igmp *igmp;
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int i;
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unsigned iplen;
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if ( ( ! ip ) || ( ip->protocol != IP_IGMP ) ||
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( nic.packetlen < ( sizeof ( struct iphdr ) +
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sizeof ( struct igmp ) ) ) ) {
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return;
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}
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iplen = ( ip->verhdrlen & 0xf ) * 4;
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igmp = ( struct igmp * ) &nic.packet[ sizeof( struct iphdr ) ];
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if ( ipchksum ( igmp, ntohs ( ip->len ) - iplen ) != 0 )
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return;
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if ( ( igmp->type == IGMP_QUERY ) &&
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( ip->dest.s_addr == htonl ( GROUP_ALL_HOSTS ) ) ) {
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unsigned long interval = IGMP_INTERVAL;
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if ( igmp->response_time == 0 ) {
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last_igmpv1 = now;
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} else {
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interval = ( igmp->response_time * TICKS_PER_SEC ) /10;
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}
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DBG ( "IGMP received query for %@\n", igmp->group.s_addr );
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for ( i = 0 ; i < MAX_IGMP ; i++ ) {
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uint32_t group = igmptable[i].group.s_addr;
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if ( ( group == 0 ) ||
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( group == igmp->group.s_addr ) ) {
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unsigned long time;
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time = currticks() +
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rfc1112_sleep_interval ( interval, 0 );
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if ( time < igmptable[i].time ) {
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igmptable[i].time = time;
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}
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}
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}
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}
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if ( ( ( igmp->type == IGMPv1_REPORT ) ||
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( igmp->type == IGMPv2_REPORT ) ) &&
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( ip->dest.s_addr == igmp->group.s_addr ) ) {
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DBG ( "IGMP received report for %@\n", igmp->group.s_addr);
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for ( i = 0 ; i < MAX_IGMP ; i++ ) {
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if ( ( igmptable[i].group.s_addr ==
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igmp->group.s_addr ) &&
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( igmptable[i].time != 0 ) ) {
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igmptable[i].time = 0;
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}
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}
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}
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}
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void leave_group ( int slot ) {
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/* Be very stupid and always send a leave group message if
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* I have subscribed. Imperfect but it is standards
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* compliant, easy and reliable to implement.
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*
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* The optimal group leave method is to only send leave when,
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* we were the last host to respond to a query on this group,
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* and igmpv1 compatibility is not enabled.
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*/
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if ( igmptable[slot].group.s_addr ) {
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struct igmp_ip_t igmp;
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igmp.router_alert[0] = 0x94;
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igmp.router_alert[1] = 0x04;
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igmp.router_alert[2] = 0;
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igmp.router_alert[3] = 0;
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build_ip_hdr ( htonl ( GROUP_ALL_HOSTS ), 1, IP_IGMP,
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sizeof ( igmp.router_alert ), sizeof ( igmp ),
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&igmp);
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igmp.igmp.type = IGMP_LEAVE;
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igmp.igmp.response_time = 0;
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igmp.igmp.chksum = 0;
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igmp.igmp.group.s_addr = igmptable[slot].group.s_addr;
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igmp.igmp.chksum = ipchksum ( &igmp.igmp, sizeof ( igmp ) );
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ip_transmit ( sizeof ( igmp ), &igmp );
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DBG ( "IGMP left group %@\n", igmp.igmp.group.s_addr );
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}
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memset ( &igmptable[slot], 0, sizeof ( igmptable[0] ) );
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}
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void join_group ( int slot, unsigned long group ) {
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/* I have already joined */
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if ( igmptable[slot].group.s_addr == group )
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return;
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if ( igmptable[slot].group.s_addr ) {
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leave_group ( slot );
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}
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/* Only join a group if we are given a multicast ip, this way
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* code can be given a non-multicast (broadcast or unicast ip)
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* and still work...
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*/
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if ( ( group & htonl ( MULTICAST_MASK ) ) ==
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htonl ( MULTICAST_NETWORK ) ) {
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igmptable[slot].group.s_addr = group;
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igmptable[slot].time = currticks();
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}
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}
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