socket: added support for multicast adressing

etc/example.conf

@@ -66,6 +66,7 @@ nodes = {
 		vectorize = 30,				# Receive and sent 30 samples per message (combining).
 		
 		netem = {				# Network emulation settings
+			enabled		= true,
 							# Those settings can be specified for each node invidually!
 			delay		= 100000,	# Additional latency in microseconds
 			jitter		= 30000,	# Jitter in uS
@@ -73,6 +74,15 @@ nodes = {
 			loss		= 10		# Packet loss in percent
 			duplicate	= 10,		# Duplication in percent
 			corrupt 	= 10		# Corruption in percent
+		},
+		
+		multicast = {				# IGMP multicast is only support for layer = (ip|udp)
+			enabled		= true,	
+			
+			group		= "224.1.2.3",	# The multicast group. Must be within 224.0.0.0/4
+			interface	= "1.2.3.4",	# The IP address of the interface which should receive multicast packets.
+			ttl		= 128,		# The time to live for outgoing multicast packets.
+			loop		= false,	# Whether or not to loopback outgoing multicast packets to the local host.
 		}
 	},
 	ethernet_node = {

include/villas/nodes/socket.h

@@ -34,6 +34,7 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <linux/if_packet.h>
+#include <netinet/in.h>
 
 #include "node.h"
 
@@ -73,6 +74,14 @@ struct socket {
 
 	union sockaddr_union local;	/**< Local address of the socket */
 	union sockaddr_union remote;	/**< Remote address of the socket */
+        
+	/* Multicast options */
+	struct multicast {
+		int enabled;		/**< Is multicast enabled? */
+		unsigned char loop;	/** Loopback multicast packets to local host? */
+		unsigned char ttl;	/**< The time to live for multicast packets. */
+		struct ip_mreq mreq;	/**< A multicast group to join. */
+	} multicast;
 
 	struct rtnl_qdisc *tc_qdisc;	/**< libnl3: Network emulator queuing discipline */
 	struct rtnl_cls *tc_classifier;	/**< libnl3: Firewall mark classifier */

lib/nodes/socket.c

@@ -142,6 +142,20 @@ char * socket_print(struct node *n)
 	char *remote = socket_print_addr((struct sockaddr *) &s->remote);
 
 	buf = strf("layer=%s, header=%s, endian=%s, local=%s, remote=%s", layer, header, endian, local, remote);
+	
+	if (s->multicast.enabled) {
+		char group[INET_ADDRSTRLEN];
+		char interface[INET_ADDRSTRLEN];
+		
+		inet_ntop(AF_INET, &s->multicast.mreq.imr_multiaddr, group, sizeof(group));
+		inet_ntop(AF_INET, &s->multicast.mreq.imr_interface, interface, sizeof(interface));
+		
+		strcatf(&buf, ", multicast.enabled=%s", s->multicast.enabled ? "yes" : "no");
+		strcatf(&buf, ", multicast.loop=%s",    s->multicast.loop    ? "yes" : "no");
+		strcatf(&buf, ", multicast.group=%s", group);
+		strcatf(&buf, ", multicast.interface=%s", s->multicast.mreq.imr_interface.s_addr == INADDR_ANY ? "any" : interface);
+		strcatf(&buf, ", multicast.ttl=%u", s->multicast.ttl);
+	}
 
 	free(local);
 	free(remote);
@@ -158,11 +172,16 @@ int socket_start(struct node *n)
 	if (s->local.sa.sa_family != s->remote.sa.sa_family)
 		error("Address families of local and remote must match!");
 	
+	if (s->layer != SOCKET_LAYER_IP && s->layer != SOCKET_LAYER_UDP) {
+		if (s->multicast.enabled)
+			error("Multicast is only supported for the IP / UDP layers");
+	}
+	
 	if (s->layer == SOCKET_LAYER_IP) {
 		if (ntohs(s->local.sin.sin_port) != ntohs(s->remote.sin.sin_port))
 			error("IP protocol numbers of local and remote must match!");
 	}
-	else if(s->layer == SOCKET_LAYER_ETH) {
+	else if (s->layer == SOCKET_LAYER_ETH) {
 		if (ntohs(s->local.sll.sll_protocol) != ntohs(s->remote.sll.sll_protocol))
 			error("Ethertypes of local and remote must match!");
 		
@@ -195,6 +214,20 @@ int socket_start(struct node *n)
 		else
 			debug(LOG_SOCKET | 4, "Set FW mark for socket (sd=%u) to %u", s->sd, s->mark);
 	}
+	
+	if (s->multicast.enabled) {
+		ret = setsockopt(s->sd, IPPROTO_IP, IP_MULTICAST_LOOP, &s->multicast.loop, sizeof(s->multicast.loop));
+		if (ret)
+			serror("Failed to set multicast loop option");
+
+	        ret = setsockopt(s->sd, IPPROTO_IP, IP_MULTICAST_TTL, &s->multicast.ttl, sizeof(s->multicast.ttl));
+		if (ret)
+			serror("Failed to set multicast ttl option");
+		
+		ret = setsockopt(s->sd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &s->multicast.mreq, sizeof(s->multicast.mreq));
+		if (ret)
+			serror("Failed to join multicast group");
+	}
 
 	/* Set socket priority, QoS or TOS IP options */
 	int prio;
@@ -234,7 +267,14 @@ int socket_reverse(struct node *n)
 
 int socket_stop(struct node *n)
 {
+	int ret;
 	struct socket *s = n->_vd;
+	
+	if (s->multicast.enabled) {
+		ret = setsockopt(s->sd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &s->multicast.mreq, sizeof(s->multicast.mreq));
+		if (ret)
+			serror("Failed to leave multicast group");
+	}
 
 	if (s->sd >= 0)
 		close(s->sd);
@@ -495,7 +535,7 @@ int socket_write(struct node *n, struct sample *smps[], unsigned cnt)
 
 int socket_parse(struct node *n, config_setting_t *cfg)
 {
-	config_setting_t *cfg_netem;
+	config_setting_t *cfg_netem, *cfg_multicast;
 	const char *local, *remote, *layer, *hdr, *endian;
 	int ret;
 
@@ -560,6 +600,46 @@ int socket_parse(struct node *n, config_setting_t *cfg)
 		cerror(cfg, "Failed to resolve remote address '%s' of node %s: %s",
 			remote, node_name(n), gai_strerror(ret));
 	}
+  
+	cfg_multicast = config_setting_get_member(cfg, "multicast");
+	if (cfg_multicast) {
+		const char *group, *interface;
+
+		if (!config_setting_lookup_bool(cfg_multicast, "enabled", &s->multicast.enabled))
+			s->multicast.enabled = true;
+		
+		if (!config_setting_lookup_string(cfg_multicast, "group", &group))
+			cerror(cfg_multicast, "The multicast group requires a 'group' setting.");
+		else {
+			ret = inet_aton(group, &s->multicast.mreq.imr_multiaddr);	
+			if (!ret) {
+				cerror(cfg_multicast, "Failed to resolve multicast group address '%s' of node %s",
+					group, node_name(n));
+			}
+		}
+		
+		if (!config_setting_lookup_string(cfg_multicast, "interface", &interface))
+			s->multicast.mreq.imr_interface.s_addr = INADDR_ANY;
+		else {
+			ret = inet_aton(group, &s->multicast.mreq.imr_interface);
+			if (!ret) {
+				cerror(cfg_multicast, "Failed to resolve multicast interface address '%s' of node %s",
+					interface, node_name(n));
+			}	
+		}
+		
+		int loop;
+		if (!config_setting_lookup_bool(cfg_multicast, "loop", &loop))
+			s->multicast.loop = 0;
+		else
+			s->multicast.loop = loop;
+	
+		int ttl;
+		if (!config_setting_lookup_int(cfg_multicast, "ttl", &ttl))
+			s->multicast.ttl = 255;
+		else
+			s->multicast.ttl = ttl;
+	} 
 
 	cfg_netem = config_setting_get_member(cfg, "netem");
 	if (cfg_netem) {