[NETROM]: Implement G8PZT Circuit reset for NET/ROM

NET/ROM is lacking a connection reset like TCP's RST flag which at times
may result in a connecting having to slowly timing out instead of just being
reset.  An earlier attempt to reset the connection by sending a
NR_CONNACK | NR_CHOKE_FLAG transport was inacceptable as it did result in
crashes of BPQ systems.  An alternative approach of introducing a new
transport type 7 (NR_RESET) has be implemented several years ago in
Paula Jayne Dowie G8PZT's Xrouter.

Implement NR_RESET for Linux's NET/ROM but like any messing with the state
engine consider this experimental for now and thus control it by a sysctl
(net.netrom.reset) which for the time being defaults to off.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 4 deletions

diff --git a/net/netrom/nr_subr.c b/net/netrom/nr_subr.c
index 587bed2674bf..bcb9946b4f56 100644
--- a/net/netrom/nr_subr.c
+++ b/net/netrom/nr_subr.c
@@ -210,10 +210,9 @@ void nr_write_internal(struct sock *sk, int frametype)
 }
 
 /*
- * This routine is called when a Connect Acknowledge with the Choke Flag
- * set is needed to refuse a connection.
+ * This routine is called to send an error reply.
  */
-void nr_transmit_refusal(struct sk_buff *skb, int mine)
+void __nr_transmit_reply(struct sk_buff *skb, int mine, unsigned char cmdflags)
 {
         struct sk_buff *skbn;
         unsigned char *dptr;
@@ -254,7 +253,7 @@ void nr_transmit_refusal(struct sk_buff *skb, int mine)
                 *dptr++ = 0;
         }
 
-        *dptr++ = NR_CONNACK | NR_CHOKE_FLAG;
+        *dptr++ = cmdflags;
         *dptr++ = 0;
 
         if (!nr_route_frame(skbn, NULL))