From 8a8d99276fbe426bfd91cf4527394b482fe4404f Mon Sep 17 00:00:00 2001
From: Brian Somers <brian@FreeBSD.org>
Date: Mon, 1 Mar 1999 02:52:39 +0000
Subject: [PATCH] Comment why we do a TLF when we get a ``Down'' event in state
 ``closing''.

Pointed out by: archie

Don't do a TLF when we get a ``Catastrphic Protocol Reject'' event
in state ``closed'' or ``stopped''.

Pointed out but not suggested by: archie

This makes no difference in the current implementation as
LcpLayerFinish() does nothing but log the event, but I disagree
in principle because it unbalances the TLF/TLS calls which
(IMHO) doesn't fit with the intentions of the RFC.

Maybe the RFC author had a reason for this.  It can only happen
in two circumstances:

- if LCP has already been negotiated then stopped or closed and we
  receive a protocol reject, then we must already have done a TLF.
  Why do one again and stay in the same state ?

- if LCP hasn't yet been started and we receive an unsolicted
  protocol reject, why should we TLF when we haven't done a TLS ?
---
 usr.sbin/ppp/fsm.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/usr.sbin/ppp/fsm.c b/usr.sbin/ppp/fsm.c
index b10daeeceb8..149087c496e 100644
--- a/usr.sbin/ppp/fsm.c
+++ b/usr.sbin/ppp/fsm.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: fsm.c,v 1.38 1999/01/28 01:56:31 brian Exp $
+ * $Id: fsm.c,v 1.39 1999/02/26 21:28:11 brian Exp $
  *
  *  TODO:
  */
@@ -302,6 +302,7 @@ fsm_Down(struct fsm *fp)
     NewState(fp, ST_INITIAL);
     break;
   case ST_CLOSING:
+    /* This TLF contradicts the RFC (1661), which ``misses it out'' ! */
     (*fp->fn->LayerFinish)(fp);
     NewState(fp, ST_INITIAL);
     (*fp->parent->LayerFinish)(fp->parent->object, fp);
@@ -841,7 +842,8 @@ FsmRecvProtoRej(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
   case PROTO_CCP:
     if (fp->proto == PROTO_LCP) {
       fp = &fp->link->ccp.fsm;
-      (*fp->fn->LayerFinish)(fp);
+      /* Despite the RFC (1661), don't do an out-of-place TLF */
+      /* (*fp->fn->LayerFinish)(fp); */
       switch (fp->state) {
       case ST_CLOSED:
       case ST_CLOSING:
@@ -850,7 +852,8 @@ FsmRecvProtoRej(struct fsm *fp, struct fsmheader *lhp, struct mbuf *bp)
         NewState(fp, ST_STOPPED);
         break;
       }
-      (*fp->parent->LayerFinish)(fp->parent->object, fp);
+      /* See above */
+      /* (*fp->parent->LayerFinish)(fp->parent->object, fp); */
     }
     break;
   case PROTO_MP: