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>
diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index cba7849..6d9c58e 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -1037,6 +1037,10 @@
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 @@
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 @@
msg->msg_namelen = sizeof(*sax);
- skb_free_datagram(sk, skb);
+out: skb_free_datagram(sk, skb);
release_sock(sk);
return copied;