config: Ensure mcast address/port differs for rrp

When using multiple interfaces, it's necessary to use different
multicast address/port pair for each interface to make
rrp work correctly. This is now checked in parser.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>

exec/totemconfig.c

@@ -1022,8 +1022,9 @@ int totem_config_validate (
 	static char local_error_reason[512];
 	char parse_error[512];
 	const char *error_reason = local_error_reason;
-	int i;
+	int i, j;
 	unsigned int interface_max = INTERFACE_MAX;
+	unsigned int port1, port2;
 
 	if (totem_config->interface_count == 0) {
 		error_reason = "No interfaces defined";
@@ -1083,6 +1084,22 @@ int totem_config_validate (
 			error_reason =  "Not all bind address belong to the same IP family";
 			goto parse_error;
 		}
+
+		/*
+		 * Ensure mcast address/port differs
+		 */
+		if (totem_config->transport_number == TOTEM_TRANSPORT_UDP) {
+			for (j = i + 1; j < totem_config->interface_count; j++) {
+				port1 = totem_config->interfaces[i].ip_port;
+				port2 = totem_config->interfaces[j].ip_port;
+				if (totemip_equal(&totem_config->interfaces[i].mcast_addr,
+				    &totem_config->interfaces[j].mcast_addr) &&
+				    (((port1 > port2 ? port1 : port2)  - (port1 < port2 ? port1 : port2)) <= 1)) {
+					error_reason = "Interfaces multicast address/port pair must differ";
+					goto parse_error;
+				}
+			}
+		}
 	}
 
 	if (totem_config->version != 2) {

man/corosync.conf.5

@@ -213,6 +213,10 @@ be chosen.
 The maximum number of interface directives that is allowed for either 
 modes (active or passive) is 2.
 
+When using multiple interfaces, make sure to use different multicast
+address/port (port for same address must differ by at least two) pair
+for each interface (this is checked by parser) to make rrp works.
+
 .TP
 netmtu
 This specifies the network maximum transmit unit.  To set this value beyond