[PATCH v4 3/5] tcp: Correct error code handling from tcp_flow_repair_socket()

[David Gibson <david@gibson.dropbear.id.au>]

There are two small bugs in error returns from tcp_low_repair_socket(),
which is supposed to return a negative errno code:

1) On bind() failures, wedirectly pass on the return code from bind(),
   which is just 0 or -1, instead of an error code.

2) In the caller, tcp_flow_migrate_target() we call strerror_() directly
   on the negative error code, but strerror() requires a positive error
   code.

Correct both of these.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 tcp.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tcp.c b/tcp.c
index e3c0a53b..8528ee35 100644
--- a/tcp.c
+++ b/tcp.c
@@ -3280,7 +3280,8 @@ int tcp_flow_repair_socket(struct ctx *c, struct tcp_tap_conn *conn)
 
 	tcp_sock_set_nodelay(s);
 
-	if ((rc = bind(s, &a.sa, sizeof(a)))) {
+	if (bind(s, &a.sa, sizeof(a))) {
+		rc = -errno;
 		err_perror("Failed to bind socket for migrated flow");
 		goto err;
 	}
@@ -3375,7 +3376,7 @@ int tcp_flow_migrate_target(struct ctx *c, int fd)
 	conn->seq_init_from_tap		= ntohl(t.seq_init_from_tap);
 
 	if ((rc = tcp_flow_repair_socket(c, conn))) {
-		flow_err(flow, "Can't set up socket: %s, drop", strerror_(rc));
+		flow_err(flow, "Can't set up socket: %s, drop", strerror_(-rc));
 		flow_alloc_cancel(flow);
 		return 0;
 	}
-- 
@@ -3280,7 +3280,8 @@ int tcp_flow_repair_socket(struct ctx *c, struct tcp_tap_conn *conn)
 
 	tcp_sock_set_nodelay(s);
 
-	if ((rc = bind(s, &a.sa, sizeof(a)))) {
+	if (bind(s, &a.sa, sizeof(a))) {
+		rc = -errno;
 		err_perror("Failed to bind socket for migrated flow");
 		goto err;
 	}
@@ -3375,7 +3376,7 @@ int tcp_flow_migrate_target(struct ctx *c, int fd)
 	conn->seq_init_from_tap		= ntohl(t.seq_init_from_tap);
 
 	if ((rc = tcp_flow_repair_socket(c, conn))) {
-		flow_err(flow, "Can't set up socket: %s, drop", strerror_(rc));
+		flow_err(flow, "Can't set up socket: %s, drop", strerror_(-rc));
 		flow_alloc_cancel(flow);
 		return 0;
 	}
-- 
2.48.1