tcp_splice: Use unsigned to represent side

Currently, we use 'int' values to represent the "side" of a connection,
which must always be 0 or 1.  This turns out to be dangerous.

In some cases we're going to want to put the side into a 1-bit bitfield.
However, if that bitfield has type 'int', when we copy it out to a regular
'int' variable, it will be sign-extended and so have values 0 and -1,
instead of 0 and 1.

To avoid this, always use unsigned variables for the side.

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

1 files changed, 4 insertions, 3 deletions

diff --git a/tcp_splice.c b/tcp_splice.c
index 081ce9c..4ab0813 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -249,7 +249,7 @@ void tcp_splice_conn_update(const struct ctx *c, struct tcp_splice_conn *new)
 void tcp_splice_destroy(struct ctx *c, union flow *flow)
 {
 	struct tcp_splice_conn *conn = &flow->tcp_splice;
-	int side;
+	unsigned side;
 
 	for (side = 0; side < SIDES; side++) {
 		if (conn->events & SPLICE_ESTABLISHED) {
@@ -286,8 +286,8 @@ void tcp_splice_destroy(struct ctx *c, union flow *flow)
 static int tcp_splice_connect_finish(const struct ctx *c,
 				     struct tcp_splice_conn *conn)
 {
+	unsigned side;
 	int i = 0;
-	int side;
 
 	for (side = 0; side < SIDES; side++) {
 		conn->pipe[side][0] = conn->pipe[side][1] = -1;
@@ -490,7 +490,8 @@ void tcp_splice_sock_handler(struct ctx *c, struct tcp_splice_conn *conn,
 			     int s, uint32_t events)
 {
 	uint8_t lowat_set_flag, lowat_act_flag;
-	int fromside, eof, never_read;
+	int eof, never_read;
+	unsigned fromside;
 
 	if (conn->events == SPLICE_CLOSED)
 		return;