From: Guus Sliepen <guus@meshlink.io>
Date: Sun, 15 Mar 2020 15:08:44 +0000 (+0100)
Subject: Fix the order of socket operations when setting up listening sockets.
X-Git-Url: http://git.meshlink.io/?p=meshlink;a=commitdiff_plain;h=097f88088e00923b74bc4c38e67feceb162ba4ef

Fix the order of socket operations when setting up listening sockets.

Commit db8e6e4 caused calls to setsockopt() for setting up socket parameters
to be called after the call to bind().
---

diff --git a/src/net.h b/src/net.h
index 63fb922f..cdb0cca5 100644
--- a/src/net.h
+++ b/src/net.h
@@ -84,8 +84,6 @@ extern void handle_incoming_vpn_data(struct event_loop_t *loop, void *, int);
 extern void finish_connecting(struct meshlink_handle *mesh, struct connection_t *);
 extern void do_outgoing_connection(struct meshlink_handle *mesh, struct outgoing_t *);
 extern void handle_new_meta_connection(struct event_loop_t *loop, void *, int);
-extern bool setup_listen_socket(struct meshlink_handle *mesh, int fd, int sa_family) __attribute__((__warn_unused_result__));
-extern bool setup_vpn_in_socket(struct meshlink_handle *mesh, int fd, int sa_family) __attribute__((__warn_unused_result__));
 extern bool send_sptps_data(void *handle, uint8_t type, const void *data, size_t len);
 extern bool receive_sptps_record(void *handle, uint8_t type, const void *data, uint16_t len) __attribute__((__warn_unused_result__));
 extern void send_packet(struct meshlink_handle *mesh, struct node_t *, struct vpn_packet_t *);
diff --git a/src/net_setup.c b/src/net_setup.c
index 4cff1a5e..d0e45003 100644
--- a/src/net_setup.c
+++ b/src/net_setup.c
@@ -301,6 +301,117 @@ static bool load_node(meshlink_handle_t *mesh, const char *name, void *priv) {
 	return true;
 }
 
+static int setup_tcp_listen_socket(meshlink_handle_t *mesh, const struct addrinfo *aip) {
+	int nfd = socket(aip->ai_family, SOCK_STREAM, IPPROTO_TCP);
+
+	if(nfd == -1) {
+		return -1;
+	}
+
+#ifdef FD_CLOEXEC
+	fcntl(nfd, F_SETFD, FD_CLOEXEC);
+#endif
+
+	int option = 1;
+	setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
+
+#if defined(IPV6_V6ONLY)
+
+	if(aip->ai_family == AF_INET6) {
+		setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
+	}
+
+#else
+#warning IPV6_V6ONLY not defined
+#endif
+
+	if(bind(nfd, aip->ai_addr, aip->ai_addrlen)) {
+		closesocket(nfd);
+		return -1;
+	}
+
+	if(listen(nfd, 3)) {
+		logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
+		closesocket(nfd);
+		return -1;
+	}
+
+	return nfd;
+}
+
+static int setup_udp_socket(meshlink_handle_t *mesh, const struct addrinfo *aip) {
+	int nfd = socket(aip->ai_family, SOCK_DGRAM, IPPROTO_UDP);
+
+	if(nfd == -1) {
+		return -1;
+	}
+
+#ifdef FD_CLOEXEC
+	fcntl(nfd, F_SETFD, FD_CLOEXEC);
+#endif
+
+#ifdef O_NONBLOCK
+	int flags = fcntl(nfd, F_GETFL);
+
+	if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
+		closesocket(nfd);
+		logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl", strerror(errno));
+		return -1;
+	}
+
+#elif defined(WIN32)
+	unsigned long arg = 1;
+
+	if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
+		closesocket(nfd);
+		logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
+		return -1;
+	}
+
+#endif
+
+	int option = 1;
+	setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
+	setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
+
+#if defined(IPV6_V6ONLY)
+
+	if(aip->ai_family == AF_INET6) {
+		setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
+	}
+
+#endif
+
+#if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
+#define IP_DONTFRAGMENT IP_DONTFRAG
+#endif
+
+#if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
+	option = IP_PMTUDISC_DO;
+	setsockopt(nfd, IPPROTO_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
+#elif defined(IP_DONTFRAGMENT)
+	option = 1;
+	setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
+#endif
+
+	if(aip->ai_family == AF_INET6) {
+#if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
+		option = IPV6_PMTUDISC_DO;
+		setsockopt(nfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
+#elif defined(IPV6_DONTFRAG)
+		option = 1;
+		setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
+#endif
+	}
+
+	if(bind(nfd, aip->ai_addr, aip->ai_addrlen)) {
+		closesocket(nfd);
+		return -1;
+	}
+
+	return nfd;
+}
+
 /*
   Add listening sockets.
 */
@@ -345,15 +456,9 @@ static bool add_listen_sockets(meshlink_handle_t *mesh) {
 
 		/* Try to bind to TCP */
 
-		int tcp_fd = socket(aip->ai_family, SOCK_STREAM, IPPROTO_TCP);
+		int tcp_fd = setup_tcp_listen_socket(mesh, aip);
 
 		if(tcp_fd == -1) {
-			continue;
-		}
-
-		if(bind(tcp_fd, aip->ai_addr, aip->ai_addrlen)) {
-			closesocket(tcp_fd);
-
 			if(errno == EADDRINUSE) {
 				/* If this port is in use for any address family, avoid it. */
 				success = false;
@@ -363,15 +468,9 @@ static bool add_listen_sockets(meshlink_handle_t *mesh) {
 			}
 		}
 
-		if(!setup_listen_socket(mesh, tcp_fd, aip->ai_family)) {
-			closesocket(tcp_fd);
-			success = false;
-			break;
-		}
-
 		/* If TCP worked, then we require that UDP works as well. */
 
-		int udp_fd = socket(aip->ai_family, SOCK_DGRAM, IPPROTO_UDP);
+		int udp_fd = setup_udp_socket(mesh, aip);
 
 		if(udp_fd == -1) {
 			closesocket(tcp_fd);
@@ -379,13 +478,6 @@ static bool add_listen_sockets(meshlink_handle_t *mesh) {
 			break;
 		}
 
-		if(bind(udp_fd, aip->ai_addr, aip->ai_addrlen) || !setup_vpn_in_socket(mesh, udp_fd, aip->ai_family)) {
-			closesocket(tcp_fd);
-			closesocket(udp_fd);
-			success = false;
-			break;
-		}
-
 		io_add(&mesh->loop, &mesh->listen_socket[mesh->listen_sockets].tcp, handle_new_meta_connection, &mesh->listen_socket[mesh->listen_sockets], tcp_fd, IO_READ);
 		io_add(&mesh->loop, &mesh->listen_socket[mesh->listen_sockets].udp, handle_incoming_vpn_data, &mesh->listen_socket[mesh->listen_sockets], udp_fd, IO_READ);
 
diff --git a/src/net_socket.c b/src/net_socket.c
index 931f21d1..fcadd90c 100644
--- a/src/net_socket.c
+++ b/src/net_socket.c
@@ -72,95 +72,6 @@ static void configure_tcp(connection_t *c) {
 #endif
 }
 
-bool setup_listen_socket(meshlink_handle_t *mesh, int nfd, int sa_family) {
-#ifdef FD_CLOEXEC
-	fcntl(nfd, F_SETFD, FD_CLOEXEC);
-#endif
-
-	int option = 1;
-	setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
-
-#if defined(IPV6_V6ONLY)
-
-	if(sa_family == AF_INET6) {
-		setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
-	}
-
-#else
-#warning IPV6_V6ONLY not defined
-#endif
-
-	if(listen(nfd, 3)) {
-		logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
-		return false;
-	}
-
-	return true;
-}
-
-bool setup_vpn_in_socket(meshlink_handle_t *mesh, int nfd, int sa_family) {
-#ifdef FD_CLOEXEC
-	fcntl(nfd, F_SETFD, FD_CLOEXEC);
-#endif
-
-#ifdef O_NONBLOCK
-	{
-		int flags = fcntl(nfd, F_GETFL);
-
-		if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
-			closesocket(nfd);
-			logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl",
-			       strerror(errno));
-			return false;
-		}
-	}
-#elif defined(WIN32)
-	{
-		unsigned long arg = 1;
-
-		if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
-			closesocket(nfd);
-			logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
-			return false;
-		}
-	}
-#endif
-
-	int option = 1;
-	setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
-	setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
-
-#if defined(IPV6_V6ONLY)
-
-	if(sa_family == AF_INET6) {
-		setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
-	}
-
-#endif
-
-#if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
-#define IP_DONTFRAGMENT IP_DONTFRAG
-#endif
-
-#if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
-	option = IP_PMTUDISC_DO;
-	setsockopt(nfd, IPPROTO_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
-#elif defined(IP_DONTFRAGMENT)
-	option = 1;
-	setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
-#endif
-
-#if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
-	option = IPV6_PMTUDISC_DO;
-	setsockopt(nfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
-#elif defined(IPV6_DONTFRAG)
-	option = 1;
-	setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
-#endif
-
-	return true;
-} /* int setup_vpn_in_socket */
-
 static void retry_outgoing_handler(event_loop_t *loop, void *data) {
 	assert(data);