netrom: zero length frame filtering in NetRom

A zero length frame filter was recently introduced in ROSE protocole. Previous commit makes the same at AX25 protocole level. This patch has the same purpose for NetRom protocole. The reason is that empty frames have no meaning in NetRom protocole. Signed-off-by: Bernard Pidoux <[email protected]> Signed-off-by: David S. Miller <[email protected]>
GunioRobot · Mar 21, 2009 · a3ac80a · a3ac80a
1 parent f99bcff
commit a3ac80a
Showing 1 changed file with 10 additions and 1 deletion.
diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
@@ -1037,6 +1037,10 @@ static int nr_sendmsg(struct kiocb *iocb, struct socket *sock,
 	unsigned char *asmptr;
 	int size;
 
+	/* Netrom empty data frame has no meaning : don't send */
+	if (len == 0)
+		return 0;
+
 	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_CMSG_COMPAT))
 		return -EINVAL;
 
@@ -1167,6 +1171,11 @@ static int nr_recvmsg(struct kiocb *iocb, struct socket *sock,
 	skb_reset_transport_header(skb);
 	copied     = skb->len;
 
+	/* NetRom empty data frame has no meaning : ignore it */
+	if (copied == 0) {
+		goto out;
+	}
+
 	if (copied > size) {
 		copied = size;
 		msg->msg_flags |= MSG_TRUNC;
@@ -1182,7 +1191,7 @@ static int nr_recvmsg(struct kiocb *iocb, struct socket *sock,
 
 	msg->msg_namelen = sizeof(*sax);
 
-	skb_free_datagram(sk, skb);
+out:	skb_free_datagram(sk, skb);
 
 	release_sock(sk);
 	return copied;