IGMP functions separated out from nic.c

src/proto/igmp.c

@@ -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();
+	}
+}
+