From 8f71f17cc087fc80f1cbe9b71852b95916a9afbc Mon Sep 17 00:00:00 2001
From: Stefano Brivio <sbrivio@redhat.com>
Date: Wed, 8 Mar 2023 12:38:39 +0100
Subject: [PATCH 14/20] 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>
(cherry picked from commit 5aea2f88ab5f63f01885109a4afb1271607fc06b)
---
 tcp.c | 21 +++++++++------------
 udp.c | 30 ++++++++++++++----------------
 2 files changed, 23 insertions(+), 28 deletions(-)

diff --git a/tcp.c b/tcp.c
index 482c2f9..001fa50 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2929,7 +2929,7 @@ 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 */
@@ -2937,19 +2937,16 @@ 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 9a43835..20ee0f2 100644
--- a/udp.c
+++ b/udp.c
@@ -962,7 +962,7 @@ 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 +
@@ -978,8 +978,8 @@ 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;
@@ -987,13 +987,10 @@ 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) {
@@ -1002,24 +999,25 @@ 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;
 }
 
 /**
-- 
2.39.2