IGMP functions separated out from nic.c
authorMichael Brown <mcb30@etherboot.org>
Wed, 1 Jun 2005 21:18:31 +0000 (21:18 +0000)
committerMichael Brown <mcb30@etherboot.org>
Wed, 1 Jun 2005 21:18:31 +0000 (21:18 +0000)
src/proto/igmp.c [new file with mode: 0644]

diff --git a/src/proto/igmp.c b/src/proto/igmp.c
new file mode 100644 (file)
index 0000000..17dae33
--- /dev/null
@@ -0,0 +1,160 @@
+/*
+ * Eric Biederman wrote this code originally.
+ *
+ */
+
+#include "ip.h"
+#include "igmp.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 ( struct iphdr *ip, unsigned long now ) {
+       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;
+                       }
+               }
+       }
+}
+
+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();
+       }
+}
+