From f2df02f242e23bff6e1ffde848e564aea415550f Mon Sep 17 00:00:00 2001
From: Paul Mackerras <paulus@samba.org>
Date: Thu, 1 Sep 1994 00:14:03 +0000
Subject: [PATCH] fix bug with sending retransmission with id=-1 after seeing
 ack.

---
 pppd/fsm.c | 23 +++++++++++++----------
 pppd/fsm.h |  3 ++-
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/pppd/fsm.c b/pppd/fsm.c
index 902ad64..ea8de82 100644
--- a/pppd/fsm.c
+++ b/pppd/fsm.c
@@ -18,7 +18,7 @@
  */
 
 #ifndef lint
-static char rcsid[] = "$Id: fsm.c,v 1.3 1994/05/24 11:21:10 paulus Exp $";
+static char rcsid[] = "$Id: fsm.c,v 1.4 1994/09/01 00:14:03 paulus Exp $";
 #endif
 
 /*
@@ -446,15 +446,16 @@ fsm_rconfack(f, id, inp, len)
     FSMDEBUG((LOG_INFO, "fsm_rconfack(%s): Rcvd id %d.",
 	      PROTO_NAME(f), id));
 
-    if (id != f->reqid)		/* Expected id? */
-	return;			/* Nope, toss... */
-    if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len): (len == 0)) ){
+    if (id != f->reqid || f->seen_ack)		/* Expected id? */
+	return;					/* Nope, toss... */
+    if( !(f->callbacks->ackci? (*f->callbacks->ackci)(f, inp, len):
+	  (len == 0)) ){
 	/* Ack is bad - ignore it */
 	FSMDEBUG((LOG_INFO, "%s: received bad Ack (length %d)",
 		  PROTO_NAME(f), len));
 	return;
     }
-    f->reqid = -1;
+    f->seen_ack = 1;
 
     switch (f->state) {
     case CLOSED:
@@ -468,7 +469,7 @@ fsm_rconfack(f, id, inp, len)
 	break;
 
     case ACKRCVD:
-	/* Huh? an extra Ack? oh well... */
+	/* Huh? an extra valid Ack? oh well... */
 	fsm_sconfreq(f, 0);
 	f->state = REQSENT;
 	break;
@@ -507,16 +508,16 @@ fsm_rconfnakrej(f, code, id, inp, len)
     FSMDEBUG((LOG_INFO, "fsm_rconfnakrej(%s): Rcvd id %d.",
 	      PROTO_NAME(f), id));
 
-    if (id != f->reqid)		/* Expected id? */
-	return;			/* Nope, toss... */
+    if (id != f->reqid || f->seen_ack)	/* Expected id? */
+	return;				/* Nope, toss... */
     proc = (code == CONFNAK)? f->callbacks->nakci: f->callbacks->rejci;
-    if( !proc || !proc(f, inp, len) ){
+    if (!proc || !proc(f, inp, len)) {
 	/* Nak/reject is bad - ignore it */
 	FSMDEBUG((LOG_INFO, "%s: received bad %s (length %d)",
 		  PROTO_NAME(f), (code==CONFNAK? "Nak": "reject"), len));
 	return;
     }
-    f->reqid = -1;
+    f->seen_ack = 1;
 
     switch (f->state) {
     case CLOSED:
@@ -715,6 +716,8 @@ fsm_sconfreq(f, retransmit)
 	f->reqid = ++f->id;
     }
 
+    f->seen_ack = 0;
+
     /*
      * Make up the request packet
      */
diff --git a/pppd/fsm.h b/pppd/fsm.h
index a12966b..22dbf65 100644
--- a/pppd/fsm.h
+++ b/pppd/fsm.h
@@ -16,7 +16,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: fsm.h,v 1.2 1994/04/11 07:18:35 paulus Exp $
+ * $Id: fsm.h,v 1.3 1994/09/01 00:14:03 paulus Exp $
  */
 
 /*
@@ -66,6 +66,7 @@ typedef struct fsm {
     int flags;			/* Contains option bits */
     u_char id;			/* Current id */
     u_char reqid;		/* Current request id */
+    u_char seen_ack;		/* Have received valid Ack/Nak/Rej to Req */
     int timeouttime;		/* Timeout time in milliseconds */
     int maxconfreqtransmits;	/* Maximum Configure-Request transmissions */
     int retransmits;		/* Number of retransmissions left */
-- 
2.39.2