cluster: Support running multiple instances on the same host

With IP_MULTICAST_LOOP they can see each other. We "just" have to make sure
they use different IP addresses and route metrics to distinguish from each
other.

cluster.c

@@ -38,7 +38,8 @@
  */
 
 // Module variables.
-extern int cluster_sockfd;		// The filedescriptor for the cluster communications port.
+extern int cluster_sockfd;		// The filedescriptor for the cluster communications multicast.
+extern int cluster_sockfd2;		// The filedescriptor for the cluster communications p2p.
 
 in_addr_t my_address = 0;		// The network address of my ethernet port.
 static int walk_session_number = 0;	// The next session to send when doing the slow table walk.
@@ -103,9 +104,10 @@ int cluster_init()
 	memset(&addr, 0, sizeof(addr));
 	addr.sin_family = AF_INET;
 	addr.sin_port = htons(config->cluster_port);
-	addr.sin_addr.s_addr = INADDR_ANY;
+	addr.sin_addr.s_addr = htonl(INADDR_ANY);
 	opt = 1;
 	setsockopt(cluster_sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+	setsockopt(cluster_sockfd, SOL_IP, IP_PKTINFO, &opt, sizeof(opt)); // recvfromto
 
 	opt = fcntl(cluster_sockfd, F_GETFL, 0);
 	fcntl(cluster_sockfd, F_SETFL, opt | O_NONBLOCK);
@@ -117,21 +119,33 @@ int cluster_init()
 	}
 
 	strcpy(ifr.ifr_name, config->cluster_interface);
-	if (ioctl(cluster_sockfd, SIOCGIFADDR, &ifr) < 0)
+	if (ioctl(cluster_sockfd, SIOCGIFADDR, &ifr) == 0)
+	{
+		memcpy(&interface_addr, &ifr.ifr_addr, sizeof(interface_addr));
+		my_address = interface_addr.sin_addr.s_addr;
+	}
+	else
+	{
+		struct in_addr myaddr;
+		if (inet_aton(config->cluster_interface, &myaddr) != 0)
+		{
+			memset(&interface_addr, 0, sizeof(interface_addr));
+			interface_addr.sin_family = AF_INET;
+			interface_addr.sin_addr = myaddr;
+			my_address = myaddr.s_addr;
+		}
+		else
 		{
 			LOG(0, 0, 0, "Failed to get interface address for (%s): %s\n", config->cluster_interface, strerror(errno));
 			return -1;
 		}
-
+	}
-	memcpy(&interface_addr, &ifr.ifr_addr, sizeof(interface_addr));
-	my_address = interface_addr.sin_addr.s_addr;
 
 	// Join multicast group.
 	mreq.imr_multiaddr.s_addr = config->cluster_address;
 	mreq.imr_interface = interface_addr.sin_addr;
 
-
+	opt = 1;	// Turn on multicast loopback.
-	opt = 0;	// Turn off multicast loopback.
 	setsockopt(cluster_sockfd, IPPROTO_IP, IP_MULTICAST_LOOP, &opt, sizeof(opt));
 
 	opt = 7;	// Highest priority to avoid getting hit by high-traffic
@@ -161,6 +175,21 @@ int cluster_init()
 	config->cluster_last_hb = TIME;
 	config->cluster_seq_number = -1;
 
+	cluster_sockfd2 = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+
+	addr.sin_addr.s_addr = my_address;
+	opt = 1;
+	setsockopt(cluster_sockfd2, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+
+	if (bind(cluster_sockfd2, (void *) &addr, sizeof(addr)) < 0)
+	{
+		LOG(0, 0, 0, "Failed to bind cluster socket2: %s\n", strerror(errno));
+		return -1;
+	}
+
+	opt = fcntl(cluster_sockfd2, F_GETFL, 0);
+	fcntl(cluster_sockfd2, F_SETFL, opt | O_NONBLOCK);
+
 	return cluster_sockfd;
 }
 
@@ -173,6 +202,7 @@ int cluster_init()
 static int cluster_send_data(void *data, int datalen)
 {
 	struct sockaddr_in addr = {0};
+	struct in_addr myaddr = { .s_addr = my_address };
 
 	if (!cluster_sockfd) return -1;
 	if (!config->cluster_address) return 0;
@@ -183,7 +213,7 @@ static int cluster_send_data(void *data, int datalen)
 
 	LOG(5, 0, 0, "Cluster send data: %d bytes\n", datalen);
 
-	if (sendto(cluster_sockfd, data, datalen, MSG_NOSIGNAL, (void *) &addr, sizeof(addr)) < 0)
+	if (sendtofrom(cluster_sockfd, data, datalen, MSG_NOSIGNAL, (void *) &addr, sizeof(addr), &myaddr) < 0)
 	{
 		LOG(0, 0, 0, "sendto: %s\n", strerror(errno));
 		return -1;
@@ -254,8 +284,7 @@ static int peer_send_data(in_addr_t peer, uint8_t *data, int size)
 {
 	struct sockaddr_in addr = {0};
 
-	if (!cluster_sockfd) return -1;
+	if (!cluster_sockfd2) return -1;
-	if (!config->cluster_address) return 0;
 
 	if (!peer)	// Odd??
 		return -1;
@@ -266,7 +295,7 @@ static int peer_send_data(in_addr_t peer, uint8_t *data, int size)
 
 	LOG_HEX(5, "Peer send", data, size);
 
-	if (sendto(cluster_sockfd, data, size, MSG_NOSIGNAL, (void *) &addr, sizeof(addr)) < 0)
+	if (sendto(cluster_sockfd2, data, size, MSG_NOSIGNAL, (void *) &addr, sizeof(addr)) < 0)
 	{
 		LOG(0, 0, 0, "sendto: %s\n", strerror(errno));
 		return -1;

docs/src/html/manual.md

@@ -348,7 +348,12 @@ should be set by a line like: set configstring \"value\" set ipaddress
 
 `cluster_interface` (string)
 
-:   Interface for cluster packets (default: eth0)
+:   Interface for cluster packets (default: eth0).
+    An IPv4 address can also be specified, e.g. to run several l2tpns on the
+    same host (but beware of enabling kernel acceleration only on one instance,
+    to set a different `bind_portremotelns`, and to set a different
+    `route_metric`. It is also useful to set a different `route_protocol`
+    number)
 
 `cluster_mcast_ttl` (int)
 

l2tpns.c

@@ -92,7 +92,8 @@ int daefd = -1;			// Socket listening for DAE connections.
 int snoopfd = -1;		// UDP file handle for sending out intercept data
 int *radfds = NULL;		// RADIUS requests file handles
 int rand_fd = -1;		// Random data source
-int cluster_sockfd = -1;	// Intra-cluster communications socket.
+int cluster_sockfd = -1;	// Intra-cluster multicast communications socket.
+int cluster_sockfd2 = -1;	// Intra-cluster p2p communications socket.
 int epollfd = -1;		// event polling
 time_t basetime = 0;		// base clock
 char hostname[MAXHOSTNAME] = "";	// us.
@@ -2386,6 +2387,9 @@ static void initdae(void)
 	addr.sin_family = AF_INET;
 	addr.sin_port = htons(config->radius_dae_port);
 	daefd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+#ifdef SO_REUSEPORT
+	setsockopt(daefd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
+#endif
 	setsockopt(daefd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
 	setsockopt(daefd, SOL_IP, IP_PKTINFO, &on, sizeof(on)); // recvfromto
 	if (bind(daefd, (struct sockaddr *) &addr, sizeof(addr)) < 0)
@@ -2407,6 +2411,9 @@ static int initudp(int * pudpfd, in_addr_t ip_bind, in_addr_t ip_dest, uint16_t
 	addr.sin_port = htons(L2TPPORT);
 	addr.sin_addr.s_addr = ip_bind;
 	(*pudpfd) = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+#ifdef SO_REUSEPORT
+	setsockopt((*pudpfd), SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
+#endif
 	setsockopt((*pudpfd), SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
 	{
 		int flags = fcntl((*pudpfd), F_GETFL, 0);
@@ -5845,8 +5852,8 @@ static int still_busy(void)
 	return 0;
 }
 
-// the base set of fds polled: cli, cluster, tun, udp (MAX_UDPFD), control, dae, netlink, udplac, pppoedisc, pppoesess, dhcpv6, icmpv6
+// the base set of fds polled: cli, cluster, cluster2, tun, udp (MAX_UDPFD), control, dae, netlink, udplac, pppoedisc, pppoesess, dhcpv6, icmpv6
-#define BASE_FDS	(11 + MAX_UDPFD)
+#define BASE_FDS	(12 + MAX_UDPFD)
 
 // additional polled fds
 #ifdef BGP
@@ -5883,8 +5890,8 @@ static void mainloop(void)
 		exit(1);
 	}
 
-	LOG(4, 0, 0, "Beginning of main loop.  clifd=%d, cluster_sockfd=%d, tunfd=%d, udpfd=%d, controlfd=%d, daefd=%d, rtnlfd=%d , udplacfd=%d, pppoefd=%d, pppoesessfd=%d\n",
+	LOG(4, 0, 0, "Beginning of main loop.  clifd=%d, cluster_sockfd=%d, cluster_sockfd=%d, tunfd=%d, udpfd=%d, controlfd=%d, daefd=%d, rtnlfd=%d , udplacfd=%d, pppoefd=%d, pppoesessfd=%d\n",
-		clifd, cluster_sockfd, tunfd, udpfd[0], controlfd, daefd, rtnlfd, udplacfd, pppoediscfd, pppoesessfd);
+		clifd, cluster_sockfd, cluster_sockfd2, tunfd, udpfd[0], controlfd, daefd, rtnlfd, udplacfd, pppoediscfd, pppoesessfd);
 
 	/* setup our fds to poll for input */
 	{
@@ -5905,6 +5912,10 @@ static void mainloop(void)
 		e.data.ptr = &d[i++];
 		epoll_ctl(epollfd, EPOLL_CTL_ADD, cluster_sockfd, &e);
 
+		d[i].type = FD_TYPE_CLUSTER2;
+		e.data.ptr = &d[i++];
+		epoll_ctl(epollfd, EPOLL_CTL_ADD, cluster_sockfd2, &e);
+
 		d[i].type = FD_TYPE_TUN;
 		e.data.ptr = &d[i++];
 		epoll_ctl(epollfd, EPOLL_CTL_ADD, tunfd, &e);
@@ -6009,7 +6020,7 @@ static void mainloop(void)
 			int pppoesess_ready = 0;
 			int pppoesess_pkts = 0;
 			int tun_ready = 0;
-			int cluster_ready = 0;
+			int cluster_ready = 0, cluster_ready2 = 0;
 			int udp_pkts[MAX_UDPFD + 1] = INIT_TABUDPVAR;
 			int tun_pkts = 0;
 			int cluster_pkts = 0;
@@ -6043,6 +6054,7 @@ static void mainloop(void)
 
 				// these are handled below, with multiple interleaved reads
 				case FD_TYPE_CLUSTER:	cluster_ready++; break;
+				case FD_TYPE_CLUSTER2:	cluster_ready2++; break;
 				case FD_TYPE_TUN:	tun_ready++; break;
 				case FD_TYPE_UDP:	udp_ready[d->index]++; break;
 				case FD_TYPE_PPPOESESS:	pppoesess_ready++; break;
@@ -6283,6 +6295,22 @@ static void mainloop(void)
 						n--;
 					}
 				}
+
+				// cluster2
+				if (cluster_ready2)
+				{
+					alen = sizeof(addr);
+					if ((s = recvfrom(cluster_sockfd2, p, size_bufp, MSG_WAITALL, (void *) &addr, &alen)) > 0)
+					{
+						processcluster(p, s, addr.sin_addr.s_addr);
+						cluster_pkts++;
+					}
+					else
+					{
+						cluster_ready2 = 0;
+						n--;
+					}
+				}
 			}
 
 			if (udp_pkts[0] > 1 || tun_pkts > 1 || cluster_pkts > 1)

l2tpns.h

@@ -1119,6 +1119,7 @@ struct event_data {
 	enum {
 		FD_TYPE_CLI,
 		FD_TYPE_CLUSTER,
+		FD_TYPE_CLUSTER2,
 		FD_TYPE_TUN,
 		FD_TYPE_UDP,
 		FD_TYPE_CONTROL,

util.c

@@ -67,7 +67,7 @@ void *shared_malloc(unsigned int size)
 }
 
 extern int forked;
-extern int cluster_sockfd, tunfd, controlfd, daefd, snoopfd, ifrfd, ifr6fd, rand_fd;
+extern int cluster_sockfd, cluster_sockfd2, tunfd, controlfd, daefd, snoopfd, ifrfd, ifr6fd, rand_fd;
 extern int pppoediscfd, pppoesessfd;
 extern int *radfds;
 extern int udpfd[MAX_UDPFD + 1];
@@ -103,6 +103,7 @@ pid_t fork_and_close()
 	// Close sockets
 	if (clifd != -1)	close(clifd);
 	if (cluster_sockfd != -1)	close(cluster_sockfd);
+	if (cluster_sockfd2 != -1)	close(cluster_sockfd2);
 	if (tunfd != -1)	close(tunfd);
 
 	for (i = 0; i < config->nbudpfd; i++)