nonblocking connect() - part 1

connection.c

@@ -44,6 +44,8 @@ static struct connection * create_connection()
 
 static int destroy_connection(struct connection *con)
 {
+	// TODO: detroy connect-timeout?
+
 	if (con->src_fd != -1) {
 		close(con->src_fd);
 		event_remove_fd(con->src_fd);
@@ -81,6 +83,24 @@ static int forward_handler(int fd, void *privdata)
 	return 0;
 }
 
+static int connect_handler(int fd, void *privdata)
+{
+	struct connection *con = (struct connection *)privdata;
+
+	if (tcp_connect_error(fd)) {
+		list_del(&con->list);
+		destroy_connection(con);
+		return -1;
+	}
+
+	log_print(LOG_INFO, "forwarding to %s", get_sockaddr_buf(&con->dst_addr));
+	event_add_readfd(con->dst_fd, forward_handler, con);
+	event_add_readfd(con->src_fd, forward_handler, con);
+
+	/* dismiss connect_handler */
+	return -1;
+}
+
 static int client_handler(int fd, void *privdata)
 {
 	struct connection *con = (struct connection *)privdata;
@@ -107,9 +127,10 @@ static int client_handler(int fd, void *privdata)
 		return -1;
 	}
 
-	log_print(LOG_INFO, "forwarding to %s", get_sockaddr_buf(&con->dst_addr));
-	event_add_readfd(con->dst_fd, forward_handler, con);
-	event_add_readfd(con->src_fd, forward_handler, con);
+	// TODO: start connect timeout, callback destroys connection
+
+	log_print(LOG_INFO, "connecting to %s", get_sockaddr_buf(&con->dst_addr));
+	event_add_writefd(con->dst_fd, connect_handler, con);
 
 	/* dismiss client_handler */
 	return -1;

network.c

@@ -4,6 +4,8 @@
 #include <string.h>
 #include <netinet/ip.h>
 #include <arpa/inet.h>
+#include <fcntl.h>
+#include <errno.h>
 
 #include "logging.h"
 
@@ -85,10 +87,54 @@ int tcp_connect_socket(struct sockaddr_in *sa)
 		return -1;
 	}
 
-	if (connect(sock, (struct sockaddr *)sa, sizeof(*sa))) {
+	int flags = fcntl(sock, F_GETFL, 0);
+	if (flags < 0) {
+		log_print(LOG_ERROR, "tcp_connect_socket(): fcntl(F_GETFL)");
+		close(sock);
+		return -1;
+	}
+
+	/* non-blocking */
+	if (fcntl(sock, F_SETFL, flags | O_NONBLOCK)) {
+		log_print(LOG_ERROR, "tcp_connect_socket(): fcntl(F_SETFL)");
+		close(sock);
+		return -1;
+	}
+
+	int ret = connect(sock, (struct sockaddr *)sa, sizeof(*sa));
+	if (ret && errno != EINPROGRESS) {
 		log_print(LOG_ERROR, "tcp_connect_socket(): bind(%s)", get_sockaddr_buf(sa));
 		close(sock);
 		return -1;
 	}
+
+	/* reset EINPROGRESS */
+	errno = 0;
+
+	/* blocking */
+	if (fcntl(sock, F_SETFL, flags)) {
+		log_print(LOG_ERROR, "tcp_connect_socket(): fcntl(F_SETFL)");
+		close(sock);
+		return -1;
+	}
+
 	return sock;
 }
+
+int tcp_connect_error(int fd)
+{
+	int err;
+	unsigned int err_size = sizeof(err);
+	if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &err_size)) {
+		log_print(LOG_ERROR, "tcp_connect_error(): getsockopt(SO_ERROR)");
+		return -1;
+	}
+
+	if (err) {
+		errno = err;
+		log_print(LOG_ERROR, "tcp_connect_error()");
+		return -1;
+	}
+
+	return 0;
+}

network.h

@@ -6,6 +6,7 @@
 int parse_saddr(const char *addr, struct sockaddr_in *sa);
 int tcp_listen_socket(struct sockaddr_in *sa);
 int tcp_connect_socket(struct sockaddr_in *sa);
+int tcp_connect_error(int fd);
 
 int get_sockaddr(struct sockaddr_in *sa, char *buf, int size);
 char * get_sockaddr_buf(struct sockaddr_in *sa);