From 70d3f132f12423a43ee5454f747f58fdde4dfb8e Mon Sep 17 00:00:00 2001
From: Tobias Klauser <tklauser@distanz.ch>
Date: Fri, 6 Feb 2015 17:26:41 +0100
Subject: Initial import, still work in progress

---
 socket.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 socket.c

(limited to 'socket.c')

diff --git a/socket.c b/socket.c
new file mode 100644
index 0000000..e00742f
--- /dev/null
+++ b/socket.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2014-2015 Tobias Klauser <tklauser@distanz.ch>
+ *
+ * This file is part of llmnrd.
+ *
+ * llmnrd is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * llmnrd is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with llmnrd.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <arpa/inet.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include "llmnr-packet.h"
+#include "log.h"
+#include "socket.h"
+
+static const int YES = 1;
+static const int NO = 0;
+
+int socket_open_v4(uint16_t port)
+{
+	int sock;
+	struct sockaddr_in sa;
+	struct ip_mreq mreq;
+
+	sock = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sock < 0) {
+		log_err("Failed to open UDP socket: %s\n", strerror(errno));
+		return -1;
+	}
+
+	/* pass pktinfo struct on received packets */
+	if (setsockopt(sock, IPPROTO_IP, IP_PKTINFO, &YES, sizeof(YES)) < 0) {
+		log_err("Failed to set IP_PKTINFO option: %s\n", strerror(errno));
+		goto err;
+	}
+
+	/* bind the socket */
+	memset(&sa, 0, sizeof(sa));
+	sa.sin_family = AF_INET;
+	sa.sin_addr.s_addr = INADDR_ANY;
+	sa.sin_port = htons(port);
+
+	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		log_err("Failed to bind() socket: %s\n", strerror(errno));
+		goto err;
+	}
+
+	/* join the multicast group */
+	memset(&mreq, 0, sizeof(mreq));
+	mreq.imr_multiaddr.s_addr = inet_addr(LLMNR_IPV4_MCAST_ADDR);
+	mreq.imr_interface.s_addr = INADDR_ANY;
+
+	if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) {
+		log_err("Failed to join multicast group: %s\n", strerror(errno));
+		goto err;
+	}
+
+	/* disable multicast loopback */
+	if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_LOOP, &NO, sizeof(NO)) < 0) {
+		log_err("Failed to disable multicast loopback: %s\n", strerror(errno));
+		goto err;
+	}
+
+	return sock;
+err:
+	close(sock);
+	return -1;
+}
+
+int socket_open_rtnl(void)
+{
+	int sock;
+	struct sockaddr_nl sa;
+
+	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (sock < 0) {
+		log_err("Failed to open netlink route socket: %s\n", strerror(errno));
+		return -1;
+	}
+
+	memset(&sa, 0, sizeof(sa));
+	sa.nl_family = AF_NETLINK;
+	/* 
+	 * listen for following events:
+	 * - network interface create/delete/up/down
+	 * - IPv4 address add/delete
+	 * - IPv6 address add/delete
+	 */
+	sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
+
+	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		log_err("Failed to bind() netlink socket: %s\n", strerror(errno));
+		goto err;
+	}
+
+	return sock;
+err:
+	close(sock);
+	return -1;
+}
-- 
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