X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=udp_send.c;h=8eee7e61ac83bd60d56c171bdf01986492e4526b;hb=82ec559332572814f76a8db3ed6751792687570d;hp=3804c39c1b96571e6a6553c97ed5dd690284c47f;hpb=7e254dc5041cc79249bf5307a19c9e04882cb3bf;p=paraslash.git

diff --git a/udp_send.c b/udp_send.c
index 3804c39c..8eee7e61 100644
--- a/udp_send.c
+++ b/udp_send.c
@@ -68,6 +68,62 @@ static void udp_delete_target(struct udp_target *ut, const char *msg)
 	free(ut);
 }
 
+/**
+ * Perform AF-independent multicast sender setup.
+ *
+ * \param fd	The connected socket descriptor.
+ * \param ttl	UDPv4 multicast TTL or UDPv6 multicast number of hops.
+ *		Use -1 to mean default, 0..255 otherwise.
+
+ ** \return Zero if okay, negative on error.
+ */
+static int mcast_sender_setup(struct udp_target *ut, int ttl)
+{
+	struct sockaddr_storage ss;
+	socklen_t sslen = sizeof(ss);
+
+	const int on = 1;
+
+	if (getpeername(ut->fd, (struct sockaddr *)&ss, &sslen) < 0)
+		goto err;
+
+	/* RFC 3493, 5.2: -1 means 'use kernel default' */
+	if (ttl < 0 || ttl > 255)
+		ttl = -1;
+
+	switch (ss.ss_family) {
+	case AF_INET:
+		if (!IN_MULTICAST(htonl(((struct sockaddr_in *)&ss)->sin_addr.s_addr)))
+			return 0;
+		/*
+		 * Enable receiving multicast messages generated on the local host
+		 * At least on Linux, this is enabled by default.
+		 */
+		if (setsockopt(ut->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &on, sizeof(on)) < 0)
+			break;
+
+		/* Default: use local subnet (do not flood out into the WAN) */
+		if (ttl == -1)
+			ttl = 1;
+		if (setsockopt(ut->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
+			break;
+		return 0;
+	case AF_INET6:
+		if (!IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)&ss)->sin6_addr))
+			return 0;
+		if (setsockopt(ut->fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &on, sizeof(on)) < 0)
+			break;
+		if (setsockopt(ut->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0)
+			break;
+		return 0;
+	default:
+		PARA_ERROR_LOG("address family %d not supported", ss.ss_family);
+		return -E_ADDRESS_LOOKUP;
+	}
+err:
+	return -ERRNO_TO_PARA_ERROR(errno);
+}
+
 /** The maximal size of the per-target chunk queue. */
 #define UDP_CQ_BYTES 40000
 
@@ -77,11 +133,18 @@ static int udp_init_session(struct udp_target *ut)
 
 	if (ut->fd >= 0) /* nothing to do */
 		return 0;
-	ret = create_udp_send_socket(TARGET_ADDR(ut), ut->port,
-		conf.udp_ttl_arg);
+
+	ret = makesock(AF_UNSPEC, IPPROTO_UDP, 0, TARGET_ADDR(ut), ut->port);
 	if (ret < 0)
 		return ret;
 	ut->fd = ret;
+
+	ret = mcast_sender_setup(ut, conf.udp_ttl_arg);
+	if (ret < 0) {
+		close(ut->fd);
+		return ret;
+	}
+
 	ret = mark_fd_nonblocking(ut->fd);
 	if (ret < 0) {
 		close(ut->fd);