lib: optimize sockunion_connect()

This function is only called with non-blocking sockets [1], so there's
no need to worry about setting O_NONBLOCK and unsetting it later if the
given fd was a blocking socket. This saves us 4 syscalls per connect,
which is not much but is something.

Also, remove an outdated comment about the return values of this
function. It returns a 'connect_result' enum now, whose values are
self-explanatory (connect_error, connect_success and connect_in_progress).

This also fixes a coverity scan warning where we weren't checking the
return value of the fcntl() syscall.

[1] bgp_connect() and pim_msdp_sock_connect().

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

1 files changed, 2 insertions, 14 deletions

diff --git a/lib/sockunion.c b/lib/sockunion.c
index 559ae37ff..ab8d8be3e 100644
--- a/lib/sockunion.c
+++ b/lib/sockunion.c
@@ -175,15 +175,11 @@ static int sockunion_sizeof(const union sockunion *su)
 	return ret;
 }
 
-/* sockunion_connect returns
-   -1 : error occured
-   0 : connect success
-   1 : connect is in progress */
+/* Performs a non-blocking connect().  */
 enum connect_result sockunion_connect(int fd, const union sockunion *peersu,
 				      unsigned short port, ifindex_t ifindex)
 {
 	int ret;
-	int val;
 	union sockunion su;
 
 	memcpy(&su, peersu, sizeof(union sockunion));
@@ -203,18 +199,12 @@ enum connect_result sockunion_connect(int fd, const union sockunion *peersu,
 		break;
 	}
 
-	/* Make socket non-block. */
-	val = fcntl(fd, F_GETFL, 0);
-	fcntl(fd, F_SETFL, val | O_NONBLOCK);
-
 	/* Call connect function. */
 	ret = connect(fd, (struct sockaddr *)&su, sockunion_sizeof(&su));
 
 	/* Immediate success */
-	if (ret == 0) {
-		fcntl(fd, F_SETFL, val);
+	if (ret == 0)
 		return connect_success;
-	}
 
 	/* If connect is in progress then return 1 else it's real error. */
 	if (ret < 0) {
@@ -227,8 +217,6 @@ enum connect_result sockunion_connect(int fd, const union sockunion *peersu,
 		}
 	}
 
-	fcntl(fd, F_SETFL, val);
-
 	return connect_in_progress;
 }