X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fnet_socket.c;h=30b36a747a0a8759dde1b9f8057cee7c29a5b062;hp=1b49aeeb4090865dd357cc235e1dffc24fe0de72;hb=38adc8bf548c2c465d5f4147866c3d3f9112d3a8;hpb=5b07039b0712bee0f19749d63116a10fb08a2d8b

diff --git a/src/net_socket.c b/src/net_socket.c
index 1b49aeeb..30b36a74 100644
--- a/src/net_socket.c
+++ b/src/net_socket.c
@@ -45,6 +45,7 @@ int maxtimeout = 900;
 int seconds_till_retry = 5;
 int udp_rcvbuf = 0;
 int udp_sndbuf = 0;
+int max_connection_burst = 100;
 
 listen_socket_t listen_socket[MAXSOCKETS];
 int listen_sockets;
@@ -112,6 +113,34 @@ static bool bind_to_interface(int sd) {
 	return true;
 }
 
+static bool bind_to_address(connection_t *c) {
+	int s = -1;
+
+	for(int i = 0; i < listen_sockets && listen_socket[i].bindto; i++) {
+		if(listen_socket[i].sa.sa.sa_family != c->address.sa.sa_family)
+			continue;
+		if(s >= 0)
+			return false;
+		s = i;
+	}
+
+	if(s < 0)
+		return false;
+
+	sockaddr_t sa = listen_socket[s].sa;
+	if(sa.sa.sa_family == AF_INET)
+		sa.in.sin_port = 0;
+	else if(sa.sa.sa_family == AF_INET6)
+		sa.in6.sin6_port = 0;
+
+	if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
+		logger(DEBUG_CONNECTIONS, LOG_WARNING, "Can't bind outgoing socket: %s", strerror(errno));
+		return false;
+	}
+
+	return true;
+}
+
 int setup_listen_socket(const sockaddr_t *sa) {
 	int nfd;
 	char *addrstr;
@@ -480,6 +509,7 @@ begin:
 #endif
 
 		bind_to_interface(c->socket);
+		bind_to_address(c);
 	}
 
 	/* Connect */
@@ -561,6 +591,57 @@ void handle_new_meta_connection(void *data, int flags) {
 
 	sockaddrunmap(&sa);
 
+	// Check if we get many connections from the same host
+
+	static sockaddr_t prev_sa;
+	static int tarpit = -1;
+
+	if(tarpit >= 0) {
+		closesocket(tarpit);
+		tarpit = -1;
+	}
+
+	if(!sockaddrcmp_noport(&sa, &prev_sa)) {
+		static int samehost_burst;
+		static int samehost_burst_time;
+
+		if(now.tv_sec - samehost_burst_time > samehost_burst)
+			samehost_burst = 0;
+		else
+			samehost_burst -= now.tv_sec - samehost_burst_time;
+
+		samehost_burst_time = now.tv_sec;
+		samehost_burst++;
+
+		if(samehost_burst > max_connection_burst) {
+			tarpit = fd;
+			return;
+		}
+	}
+
+	memcpy(&prev_sa, &sa, sizeof sa);
+
+	// Check if we get many connections from different hosts
+
+	static int connection_burst;
+	static int connection_burst_time;
+
+	if(now.tv_sec - connection_burst_time > connection_burst)
+		connection_burst = 0;
+	else
+		connection_burst -= now.tv_sec - connection_burst_time;
+
+	connection_burst_time = now.tv_sec;
+	connection_burst++;
+
+	if(connection_burst >= max_connection_burst) {
+		connection_burst = max_connection_burst;
+		tarpit = fd;
+		return;
+	}
+
+	// Accept the new connection
+
 	c = new_connection();
 	c->name = xstrdup("<unknown>");
 	c->outcipher = myself->connection->outcipher;