X-Git-Url: https://git.sesse.net/?p=cubemap;a=blobdiff_plain;f=udpinput.cpp;h=5e39d6632c9b72ca6916816283df44ffa8ef1820;hp=6b1779989f26d4a55abe928d6af7ae9553525f3b;hb=70c47a998c5aa2eb536c3c8f71f3178cd217a14d;hpb=a2f189dc473049aec372f2b26930d19b54025a9d

diff --git a/udpinput.cpp b/udpinput.cpp
index 6b17799..5e39d66 100644
--- a/udpinput.cpp
+++ b/udpinput.cpp
@@ -22,13 +22,91 @@ using namespace std;
 
 extern ServerPool *servers;
 
+namespace {
+
+// Similar to parse_hostport(), but only parses the IP address,
+// and does not use mapped-v4 addresses, since multicast seems
+// to not like that too much.
+bool parse_ip_address(const string &ip, sockaddr_storage *addr)
+{
+	memset(addr, 0, sizeof(*addr));
+
+	assert(!ip.empty());
+	if (ip[0] == '[') {
+		sockaddr_in6 *addr6 = (sockaddr_in6 *)addr;
+		addr6->sin6_family = AF_INET6;
+		if (ip[ip.size() - 1] != ']') {
+			log(ERROR, "address '%s' is malformed; must be either [ipv6addr] or ipv4addr",
+				ip.c_str());
+			return false;
+		}
+		if (inet_pton(AF_INET6, ip.c_str(), &addr6->sin6_addr) != 1) {
+			log(ERROR, "'%s' is not a valid IPv6 address");
+			return false;
+		}
+	} else {
+		sockaddr_in *addr4 = (sockaddr_in *)addr;
+		addr4->sin_family = AF_INET;
+		if (inet_pton(AF_INET, ip.c_str(), &addr4->sin_addr) != 1) {
+			log(ERROR, "'%s' is not a valid IPv4 address");
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool maybe_join_multicast_group(int sock, const string &group, const string &source)
+{
+	if (group.empty()) {
+		// Not multicast.
+		return true;
+	}
+
+	// Join the given multicast group (ASM or SSM).
+	// TODO: Also support sources apart from multicast groups,
+	// e.g. udp://[::1]:1234 for only receiving from localhost.
+	if (!source.empty()) {
+		// Single-Source Multicast (SSM).
+		group_source_req gsr;
+		memset(&gsr, 0, sizeof(gsr));
+		if (!parse_ip_address(group, &gsr.gsr_group)) {
+			return false;
+		}
+		if (!parse_ip_address(source, &gsr.gsr_source)) {
+			return false;
+		}
+		int level = (gsr.gsr_group.ss_family == AF_INET) ? SOL_IP : SOL_IPV6;
+		if (setsockopt(sock, level, MCAST_JOIN_SOURCE_GROUP, &gsr, sizeof(gsr)) == -1) {
+			log_perror("setsockopt(MCAST_JOIN_SOURCE_GROUP)");
+			return false;
+		}
+	} else {
+		// Any-Source Multicast (ASM).
+		group_req gr;
+		memset(&gr, 0, sizeof(gr));
+		if (!parse_ip_address(group, &gr.gr_group)) {
+			return false;
+		}
+		int level = (gr.gr_group.ss_family == AF_INET) ? SOL_IP : SOL_IPV6;
+		if (setsockopt(sock, level, MCAST_JOIN_GROUP, &gr, sizeof(gr)) == -1) {
+			log_perror("setsockopt(MCAST_JOIN_GROUP)");
+			return false;
+		}
+	}
+
+	return true;
+}
+
+}  // namespace
+
 UDPInput::UDPInput(const string &url)
 	: url(url),
 	  sock(-1)
 {
 	// Should be verified by the caller.
 	string protocol;
-	bool ok = parse_url(url, &protocol, &host, &port, &path);
+	bool ok = parse_url(url, &protocol, &user, &host, &port, &path);
 	assert(ok);
 
 	construct_header();
@@ -46,7 +124,7 @@ UDPInput::UDPInput(const InputProto &serialized)
 {
 	// Should be verified by the caller.
 	string protocol;
-	bool ok = parse_url(url, &protocol, &host, &port, &path);
+	bool ok = parse_url(url, &protocol, &user, &host, &port, &path);
 	assert(ok);
 
 	construct_header();
@@ -108,6 +186,18 @@ void UDPInput::do_work()
 				usleep(200000);
 				continue;
 			}
+
+			// The syntax udp://source@group (abusing the username field
+			// to store the sender in SSM) seems to be a VLC invention.
+			// We mimic it.
+			if (!maybe_join_multicast_group(sock, host, user)) {
+				log(WARNING, "[%s] Multicast join failed. Waiting 0.2 seconds and trying again...",
+				             url.c_str());
+				safe_close(sock);
+				sock = -1;
+				usleep(200000);
+				continue;
+			}
 		}
 
 		// Wait for a packet, or a wakeup.