X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=net.c;h=312a68546f08bc5493699a9ae32d6a4b96164e13;hp=9309ac1f02dc63edcc7af2939686b10b6d9b0599;hb=de9a70360fcd3b5285d280ad1f229f679d453603;hpb=40de1dd2fdbb054444d585aa70e2d50166a66e07

diff --git a/net.c b/net.c
index 9309ac1f..312a6854 100644
--- a/net.c
+++ b/net.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -755,3 +755,142 @@ out:
 	free(buf);
 	return ret;
 }
+
+static int resolve(const char *hostname, unsigned short port,
+		struct sockaddr_in *addr)
+{
+	struct hostent *host;
+
+	assert(hostname);
+	host = gethostbyname(hostname);
+	if (!host)
+		return -ERRNO_TO_PARA_ERROR(h_errno);
+	if (addr) {
+		memcpy(&addr->sin_addr, host->h_addr_list[0], host->h_length);
+		addr->sin_port = port;
+	}
+	return 1;
+}
+
+/*
+ * Create an UDP socket.
+ *
+ * If the given address is a multicast adress, the socket will be set
+ * to use the multicast TTL ttl and sets the datagrams to loop back.
+ *
+ * \return The fd of the socket on success, negative on errors.
+ */
+static int create_udp_socket(struct sockaddr_in *addr,
+		unsigned short port, unsigned char ttl)
+{
+	int ret, fd, yes = 1;
+
+	assert(addr);
+	ret = socket(PF_INET, SOCK_DGRAM, 0);
+	if (ret < 0)
+		return -ERRNO_TO_PARA_ERROR(errno);
+	fd = ret;
+	/* reuse addresses */
+	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
+	if (ret < 0) {
+		ret = -ERRNO_TO_PARA_ERROR(errno);
+		goto err;
+	}
+	addr->sin_family = AF_INET;
+	addr->sin_port = htons(port);
+	/* set the TTL and turn on multicast loop */
+	if (IN_MULTICAST(htonl(addr->sin_addr.s_addr))) {
+		unsigned char loop = 1;
+		ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl,
+			sizeof(ttl));
+		if (ret < 0) {
+			ret = -ERRNO_TO_PARA_ERROR(errno);
+			goto err;
+		}
+		ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &loop,
+			sizeof(loop));
+		if (ret < 0) {
+			ret = -ERRNO_TO_PARA_ERROR(errno);
+			goto err;
+		}
+	}
+	return fd;
+err:
+	close(fd);
+	return ret;
+}
+
+/**
+ * Create and connect a sending UDP socket.
+ *
+ * \param hostname Where to send to (name or IPv4 address).
+ * \param port The udp port to use.
+ * \param ttl Time to live (only relevant for multicast).
+ *
+ * \return The fd of the socket on success, negative on error.
+ */
+int create_udp_send_socket(char *hostname, unsigned short port,
+		unsigned char ttl)
+{
+	struct sockaddr_in addr;
+	int fd, ret = resolve(hostname, port, &addr);
+
+	if (ret < 0)
+		return ret;
+	ret = create_udp_socket(&addr, port, ttl);
+	if (ret < 0)
+		return ret;
+	fd = ret;
+	ret = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
+	if (ret >= 0)
+		return fd;
+	ret = -ERRNO_TO_PARA_ERROR(errno);
+	close(fd);
+	return ret;
+}
+
+/**
+ * Create and bind a receiving UDP socket.
+ *
+ * Bind the created UDP socket to \a hostname, and add multicast membership if
+ * hostname is a multicast hostname.
+ *
+ * \param hostname Name or IPv4 address to receive from.
+ * \param port The udp port.
+ *
+ * \return The fd of the socket on success, negative on errors.
+ */
+int create_udp_recv_socket(char *hostname, unsigned short port)
+{
+	struct sockaddr_in addr;
+	int fd, ret = resolve(hostname, port, &addr);
+
+	if (ret < 0)
+		memset(&addr.sin_addr, 0, sizeof(addr.sin_addr));
+	ret = create_udp_socket(&addr, port, 1);
+	if (ret < 0)
+		return ret;
+	fd = ret;
+	ret = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
+	if (ret < 0) {
+		ret = -ERRNO_TO_PARA_ERROR(errno);
+		goto err;
+	}
+	/* Add multicast membership */
+	if (IN_MULTICAST(htonl(addr.sin_addr.s_addr))) {
+		struct ip_mreq mreq;
+
+		mreq.imr_multiaddr.s_addr = addr.sin_addr.s_addr;
+		mreq.imr_interface.s_addr = htonl(INADDR_ANY);
+		ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+			&mreq, sizeof(mreq));
+		if (ret < 0) {
+			ret = -ERRNO_TO_PARA_ERROR(errno);
+			goto err;
+		}
+	}
+	return fd;
+err:
+	close(fd);
+	return ret;
+}