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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 <f6bvp@amsat.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bernard Pidoux 16 年之前
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當前提交
a3ac80a130
共有 1 個文件被更改,包括 10 次插入1 次删除
  1. 10 1
      net/netrom/af_netrom.c

+ 10 - 1
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;