tcp, udp, util: Pass socket creation errors all the way up

...starting from sock_l4(), pass negative error (errno) codes instead
of -1. They will only be used in two commits from now, no functional
changes intended here.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

3 files changed, 39 insertions, 32 deletions

diff --git a/tcp.c b/tcp.c
index 96ca5c7..e209483 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2955,7 +2955,7 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
  * @addr:	Pointer to address for binding, NULL if not configured
  * @ifname:	Name of interface to bind to, NULL if not configured
  *
- * Return: fd for the new listening socket, or -1 on failure
+ * Return: fd for the new listening socket, negative error code on failure
  */
 static int tcp_sock_init_af(const struct ctx *c, int af, in_port_t port,
 			    const struct in_addr *addr, const char *ifname)
@@ -2968,13 +2968,13 @@ static int tcp_sock_init_af(const struct ctx *c, int af, in_port_t port,
 
 	if (c->tcp.fwd_in.mode == FWD_AUTO) {
 		if (af == AF_INET  || af == AF_UNSPEC)
-			tcp_sock_init_ext[port][V4] = s;
+			tcp_sock_init_ext[port][V4] = s < 0 ? -1 : s;
 		if (af == AF_INET6 || af == AF_UNSPEC)
-			tcp_sock_init_ext[port][V6] = s;
+			tcp_sock_init_ext[port][V6] = s < 0 ? -1 : s;
 	}
 
 	if (s < 0)
-		return -1;
+		return s;
 
 	tcp_sock_set_bufsize(c, s);
 	return s;
@@ -2988,12 +2988,12 @@ static int tcp_sock_init_af(const struct ctx *c, int af, in_port_t port,
  * @ifname:	Name of interface to bind to, NULL if not configured
  * @port:	Port, host order
  *
- * Return: 0 on (partial) success, -1 on (complete) failure
+ * Return: 0 on (partial) success, negative error code on (complete) failure
  */
 int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
 		  const char *ifname, in_port_t port)
 {
-	int ret = 0;
+	int ret = 0, af_ret;
 
 	if (af == AF_UNSPEC && c->ifi4 && c->ifi6)
 		/* Attempt to get a dual stack socket */
@@ -3002,13 +3002,15 @@ int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
 
 	/* Otherwise create a socket per IP version */
 	if ((af == AF_INET  || af == AF_UNSPEC) && c->ifi4) {
-		if (tcp_sock_init_af(c, AF_INET, port, addr, ifname) < 0)
-			ret = -1;
+		af_ret = tcp_sock_init_af(c, AF_INET, port, addr, ifname);
+		if (af_ret < 0)
+			ret = af_ret;
 	}
 
 	if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6) {
-		if (tcp_sock_init_af(c, AF_INET6, port, addr, ifname) < 0)
-			ret = -1;
+		af_ret = tcp_sock_init_af(c, AF_INET6, port, addr, ifname);
+		if (af_ret < 0)
+			ret = af_ret;
 	}
 
 	return ret;
diff --git a/udp.c b/udp.c
index 0a711f6..0ac0a3a 100644
--- a/udp.c
+++ b/udp.c
@@ -977,7 +977,7 @@ int udp_tap_handler(struct ctx *c, int af, const void *addr,
  * @ifname:	Name of interface to bind to, NULL if not configured
  * @port:	Port, host order
  *
- * Return: 0 on (partial) success, -1 on (complete) failure
+ * Return: 0 on (partial) success, negative error code on (complete) failure
  */
 int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 		  const void *addr, const char *ifname, in_port_t port)
@@ -1002,19 +1002,19 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 			s = sock_l4(c, AF_INET, IPPROTO_UDP, addr, ifname,
 				    port, uref.u32);
 
-			udp_tap_map[V4][uref.udp.port].sock = s;
-			udp_splice_init[V4][port].sock = s;
+			udp_tap_map[V4][uref.udp.port].sock = s < 0 ? -1 : s;
+			udp_splice_init[V4][port].sock = s < 0 ? -1 : s;
 		} else {
 			struct in_addr loopback = { htonl(INADDR_LOOPBACK) };
 			uref.udp.ns = true;
 
 			s = sock_l4(c, AF_INET, IPPROTO_UDP, &loopback,
 				    ifname, port, uref.u32);
-			udp_splice_ns[V4][port].sock = s;
+			udp_splice_ns[V4][port].sock = s < 0 ? -1 : s;
 		}
 
 		if (s < 0)
-			ret = -1;
+			ret = s;
 	}
 
 	if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6) {
@@ -1026,18 +1026,18 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 			s = sock_l4(c, AF_INET6, IPPROTO_UDP, addr, ifname,
 				    port, uref.u32);
 
-			udp_tap_map[V6][uref.udp.port].sock = s;
-			udp_splice_init[V6][port].sock = s;
+			udp_tap_map[V6][uref.udp.port].sock = s < 0 ? -1 : s;
+			udp_splice_init[V6][port].sock = s < 0 ? -1 : s;
 		} else {
 			uref.udp.ns = true;
 
 			s = sock_l4(c, AF_INET6, IPPROTO_UDP, &in6addr_loopback,
 				    ifname, port, uref.u32);
-			udp_splice_ns[V6][port].sock = s;
+			udp_splice_ns[V6][port].sock = s < 0 ? -1 : s;
 		}
 
 		if (s < 0)
-			ret = -1;
+			ret = s;
 	}
 
 	return ret;
diff --git a/util.c b/util.c
index 484889b..fddb5ed 100644
--- a/util.c
+++ b/util.c
@@ -96,7 +96,7 @@ found:
  * @port:	Port, host order
  * @data:	epoll reference portion for protocol handlers
  *
- * Return: newly created socket, -1 on error
+ * Return: newly created socket, negative error code on failure
  */
 int sock_l4(const struct ctx *c, int af, uint8_t proto,
 	    const void *bind_addr, const char *ifname, uint16_t port,
@@ -115,16 +115,16 @@ int sock_l4(const struct ctx *c, int af, uint8_t proto,
 	};
 	const struct sockaddr *sa;
 	bool dual_stack = false;
+	int fd, sl, y = 1, ret;
 	struct epoll_event ev;
-	int fd, sl, y = 1;
 
 	if (proto != IPPROTO_TCP && proto != IPPROTO_UDP &&
 	    proto != IPPROTO_ICMP && proto != IPPROTO_ICMPV6)
-		return -1;	/* Not implemented. */
+		return -EPFNOSUPPORT;	/* Not implemented. */
 
 	if (af == AF_UNSPEC) {
 		if (!DUAL_STACK_SOCKETS || bind_addr)
-			return -1;
+			return -EINVAL;
 		dual_stack = true;
 		af = AF_INET6;
 	}
@@ -134,14 +134,15 @@ int sock_l4(const struct ctx *c, int af, uint8_t proto,
 	else
 		fd = socket(af, SOCK_DGRAM | SOCK_NONBLOCK, proto);
 
+	ret = -errno;
 	if (fd < 0) {
-		warn("L4 socket: %s", strerror(errno));
-		return -1;
+		warn("L4 socket: %s", strerror(-ret));
+		return ret;
 	}
 
 	if (fd > SOCKET_MAX) {
 		close(fd);
-		return -1;
+		return -EBADF;
 	}
 
 	ref.r.s = fd;
@@ -186,10 +187,11 @@ int sock_l4(const struct ctx *c, int af, uint8_t proto,
 		 */
 		if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
 			       ifname, strlen(ifname))) {
+			ret = -errno;
 			warn("Can't bind socket for %s port %u to %s, closing",
 			     ip_proto_str[proto], port, ifname);
 			close(fd);
-			return -1;
+			return ret;
 		}
 	}
 
@@ -200,22 +202,25 @@ int sock_l4(const struct ctx *c, int af, uint8_t proto,
 		 * broken SELinux policy, see icmp_tap_handler().
 		 */
 		if (proto != IPPROTO_ICMP && proto != IPPROTO_ICMPV6) {
+			ret = -errno;
 			close(fd);
-			return -1;
+			return ret;
 		}
 	}
 
 	if (proto == IPPROTO_TCP && listen(fd, 128) < 0) {
-		warn("TCP socket listen: %s", strerror(errno));
+		ret = -errno;
+		warn("TCP socket listen: %s", strerror(-ret));
 		close(fd);
-		return -1;
+		return ret;
 	}
 
 	ev.events = EPOLLIN;
 	ev.data.u64 = ref.u64;
 	if (epoll_ctl(c->epollfd, EPOLL_CTL_ADD, fd, &ev) == -1) {
-		warn("L4 epoll_ctl: %s", strerror(errno));
-		return -1;
+		ret = -errno;
+		warn("L4 epoll_ctl: %s", strerror(-ret));
+		return ret;
 	}
 
 	return fd;