tcp, udp: Fix partial success return codes in {tcp,udp}_sock_init()

The comments say we should return 0 on partial success, and an error
code on complete failure. Rationale: if the user configures a port
forwarding, and we succeed to bind that port for IPv4 or IPv6 only,
that might actually be what the user intended.

Adjust the two functions to reflect the comments.

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

2 files changed, 23 insertions, 28 deletions

diff --git a/tcp.c b/tcp.c
index e209483..a29e387 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2993,7 +2993,7 @@ static int tcp_sock_init_af(const struct ctx *c, int af, in_port_t port,
 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, af_ret;
+	int r4 = SOCKET_MAX + 1, r6 = SOCKET_MAX + 1;
 
 	if (af == AF_UNSPEC && c->ifi4 && c->ifi6)
 		/* Attempt to get a dual stack socket */
@@ -3001,19 +3001,16 @@ int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
 			return 0;
 
 	/* Otherwise create a socket per IP version */
-	if ((af == AF_INET  || af == AF_UNSPEC) && c->ifi4) {
-		af_ret = tcp_sock_init_af(c, AF_INET, port, addr, ifname);
-		if (af_ret < 0)
-			ret = af_ret;
-	}
+	if ((af == AF_INET  || af == AF_UNSPEC) && c->ifi4)
+		r4 = tcp_sock_init_af(c, AF_INET, port, addr, ifname);
 
-	if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6) {
-		af_ret = tcp_sock_init_af(c, AF_INET6, port, addr, ifname);
-		if (af_ret < 0)
-			ret = af_ret;
-	}
+	if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6)
+		r6 = tcp_sock_init_af(c, AF_INET6, port, addr, ifname);
 
-	return ret;
+	if (IN_INTERVAL(0, SOCKET_MAX, r4) || IN_INTERVAL(0, SOCKET_MAX, r6))
+		return 0;
+
+	return r4 < 0 ? r4 : r6;
 }
 
 /**
diff --git a/udp.c b/udp.c
index 0ac0a3a..b7bc4f3 100644
--- a/udp.c
+++ b/udp.c
@@ -983,7 +983,7 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 		  const void *addr, const char *ifname, in_port_t port)
 {
 	union udp_epoll_ref uref = { .u32 = 0 };
-	int s, ret = 0;
+	int s, r4 = SOCKET_MAX + 1, r6 = SOCKET_MAX + 1;
 
 	if (ns) {
 		uref.udp.port = (in_port_t)(port +
@@ -999,8 +999,8 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 		uref.udp.orig = true;
 
 		if (!ns) {
-			s = sock_l4(c, AF_INET, IPPROTO_UDP, addr, ifname,
-				    port, uref.u32);
+			r4 = s = sock_l4(c, AF_INET, IPPROTO_UDP, addr,
+					 ifname, port, uref.u32);
 
 			udp_tap_map[V4][uref.udp.port].sock = s < 0 ? -1 : s;
 			udp_splice_init[V4][port].sock = s < 0 ? -1 : s;
@@ -1008,13 +1008,10 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 			struct in_addr loopback = { htonl(INADDR_LOOPBACK) };
 			uref.udp.ns = true;
 
-			s = sock_l4(c, AF_INET, IPPROTO_UDP, &loopback,
-				    ifname, port, uref.u32);
+			r4 = s = sock_l4(c, AF_INET, IPPROTO_UDP, &loopback,
+					 ifname, port, uref.u32);
 			udp_splice_ns[V4][port].sock = s < 0 ? -1 : s;
 		}
-
-		if (s < 0)
-			ret = s;
 	}
 
 	if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6) {
@@ -1023,24 +1020,25 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 		uref.udp.orig = true;
 
 		if (!ns) {
-			s = sock_l4(c, AF_INET6, IPPROTO_UDP, addr, ifname,
-				    port, uref.u32);
+			r6 = s = sock_l4(c, AF_INET6, IPPROTO_UDP, addr,
+					 ifname, port, uref.u32);
 
 			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);
+			r6 = s = sock_l4(c, AF_INET6, IPPROTO_UDP,
+					 &in6addr_loopback,
+					 ifname, port, uref.u32);
 			udp_splice_ns[V6][port].sock = s < 0 ? -1 : s;
 		}
-
-		if (s < 0)
-			ret = s;
 	}
 
-	return ret;
+	if (IN_INTERVAL(0, SOCKET_MAX, r4) || IN_INTERVAL(0, SOCKET_MAX, r6))
+		return 0;
+
+	return r4 < 0 ? r4 : r6;
 }
 
 /**