From a3ac80a130300573de351083cf4a5b46d233e8bf Mon Sep 17 00:00:00 2001 From: Bernard Pidoux Date: Sat, 21 Mar 2009 13:34:20 -0700 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/netrom/af_netrom.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c index cba7849de98..6d9c58ec56a 100644 --- 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; -- 2.20.1