Implement Reset{Req,Ack} properly, as per rfc 1962.

(I completely mis-read the rfc last time 'round!)

This means:
  o Better CCP/WARN Reset diagnostics.
  o After we've sent a REQ and before we've received an ACK, we drop
    incoming compressed data and send another REQ.
  o Before sending an ACK, re-sequence all pending PRI_NORMAL data in
    the modem queue so that pending packets won't get to the peer
    *after* the ResetAck.
  o Send ACKs with the `identifier' from the REQ frame.
  o After we've received a correct ACK, duplicate ACKs are ok (and will
    reset our history).
  o Incorrect ACKs (not matching the last REQ) are moaned about and dropped.

Also,

  o Calculate the correct FCS after compressing a packet.  DEFLATE
    *may* produce an mbuf with more than a single link in the chain,
    but HdlcOutput didn't know how to calculate the FCS :-(
  o Make `struct fsm'::reqid a u_char, not an int.
    This fix will prevent us from sending id `255' 2,000,000,000 times
    before wrapping to `0' for another 2,000,000,000 sends :-/
  o Bump the version number a little (it should already have been at 1.6).

The end result:  DEFLATE now works over an unreliable link layer.
                 I can txfr a 1.5Mb kernel over a (rather bad) null-modem
                 cable at an average of 21679 bytes per second using rcp.
Repeat after me: Don't test compression using a loopback ppp/tcp setup as
                 we never lose packets and therefore never have to reset!

9 files changed, 84 insertions, 42 deletions

diff --git a/usr.sbin/ppp/ccp.c b/usr.sbin/ppp/ccp.c
index c0fb3e236f0..6b6a960858c 100644
--- a/usr.sbin/ppp/ccp.c
+++ b/usr.sbin/ppp/ccp.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: ccp.c,v 1.7 1998/01/04 20:29:21 brian Exp $
+ * $Id: ccp.c,v 1.8 1998/01/10 01:55:13 brian Exp $
  *
  *	TODO:
  *		o Support other compression protocols
@@ -43,7 +43,7 @@
 #include "pred.h"
 #include "deflate.h"
 
-struct ccpstate CcpInfo = { -1, -1 };
+struct ccpstate CcpInfo = { -1, -1, -1, -1 };
 
 static void CcpSendConfigReq(struct fsm *);
 static void CcpSendTerminateReq(struct fsm *);
@@ -146,6 +146,7 @@ ccpstateInit(void)
   out_algorithm = -1;
   memset(&CcpInfo, '\0', sizeof CcpInfo);
   CcpInfo.his_proto = CcpInfo.my_proto = -1;
+  CcpInfo.reset_sent = CcpInfo.last_reset = -1;
 }
 
 void
@@ -189,7 +190,9 @@ CcpSendConfigReq(struct fsm *fp)
 void
 CcpSendResetReq(struct fsm *fp)
 {
-  LogPrintf(LogCCP, "CcpSendResetReq\n");
+  LogPrintf(LogCCP, "SendResetReq(%d)\n", fp->reqid);
+  CcpInfo.reset_sent = fp->reqid;
+  CcpInfo.last_reset = -1;
   FsmOutput(fp, CODE_RESETREQ, fp->reqid, NULL, 0);
 }
 
@@ -378,8 +381,24 @@ CcpInput(struct mbuf *bp)
 }
 
 void
-CcpResetInput()
+CcpResetInput(u_char id)
 {
+  if (CcpInfo.reset_sent != -1) {
+    if (id != CcpInfo.reset_sent) {
+      LogPrintf(LogWARN, "CCP: Incorrect ResetAck (id %d, not %d) ignored\n",
+                id, CcpInfo.reset_sent);
+      return;
+    }
+    /* Whaddaya know - a correct reset ack */
+  } else if (id == CcpInfo.last_reset)
+    LogPrintf(LogCCP, "Duplicate ResetAck (resetting again)\n");
+  else {
+    LogPrintf(LogWARN, "CCP: Unexpected ResetAck (id %d) ignored\n", id);
+    return;
+  }
+
+  CcpInfo.last_reset = CcpInfo.reset_sent;
+  CcpInfo.reset_sent = -1;
   if (in_algorithm >= 0 && in_algorithm < NALGORITHMS)
     (*algorithm[in_algorithm]->i.Reset)();
 }
@@ -395,7 +414,12 @@ CcpOutput(int pri, u_short proto, struct mbuf *m)
 struct mbuf *
 CompdInput(u_short *proto, struct mbuf *m)
 {
-  if (in_algorithm >= 0 && in_algorithm < NALGORITHMS)
+  if (CcpInfo.reset_sent != -1) {
+    /* Send another REQ and put the packet in the bit bucket */
+    LogPrintf(LogCCP, "ReSendResetReq(%d)\n", CcpInfo.reset_sent);
+    FsmOutput(&CcpFsm, CODE_RESETREQ, CcpInfo.reset_sent, NULL, 0);
+    pfree(m);
+  } else if (in_algorithm >= 0 && in_algorithm < NALGORITHMS)
     return (*algorithm[in_algorithm]->i.Read)(proto, m);
   return NULL;
 }
diff --git a/usr.sbin/ppp/ccp.h b/usr.sbin/ppp/ccp.h
index 732ccafc3db..b10ad9e8280 100644
--- a/usr.sbin/ppp/ccp.h
+++ b/usr.sbin/ppp/ccp.h
@@ -15,7 +15,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: ccp.h,v 1.3 1998/01/04 20:29:22 brian Exp $
+ * $Id: ccp.h,v 1.4 1998/01/10 01:55:14 brian Exp $
  *
  *	TODO:
  */
@@ -39,6 +39,9 @@ struct ccpstate {
   u_long his_proto;		/* peer's compression protocol */
   u_long my_proto;		/* our compression protocol */
 
+  int reset_sent;		/* If != -1, ignore compressed 'till ack */
+  int last_reset;		/* We can receive more (dups) w/ this id */
+
   u_long his_reject;		/* Request codes rejected by peer */
   u_long my_reject;		/* Request codes I have rejected */
 
@@ -83,7 +86,7 @@ extern void CcpUp(void);
 extern void CcpOpen(void);
 extern void CcpInit(void);
 extern int ReportCcpStatus(struct cmdargs const *);
-extern void CcpResetInput(void);
+extern void CcpResetInput(u_char);
 extern int CcpOutput(int, u_short, struct mbuf *);
 extern struct mbuf *CompdInput(u_short *, struct mbuf *);
 extern void CcpDictSetup(u_short, struct mbuf *);
diff --git a/usr.sbin/ppp/deflate.c b/usr.sbin/ppp/deflate.c
index 5ac759d60b3..6973cdbddab 100644
--- a/usr.sbin/ppp/deflate.c
+++ b/usr.sbin/ppp/deflate.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: deflate.c,v 1.4 1997/12/28 02:16:34 brian Exp $
+ *	$Id: deflate.c,v 1.5 1998/01/10 01:55:14 brian Exp $
  */
 
 #include <sys/param.h>
@@ -50,7 +50,7 @@
 /* Our state */
 struct deflate_state {
     u_short seqno;
-    int dodgy_seqno;
+    int uncomp_rec;
     z_stream cx;
 };
 
@@ -66,7 +66,7 @@ static void
 DeflateResetOutput(void)
 {
   OutputState.seqno = 0;
-  OutputState.dodgy_seqno = 0;
+  OutputState.uncomp_rec = 0;
   deflateReset(&OutputState.cx);
   LogPrintf(LogCCP, "Deflate: Output channel reset\n");
 }
@@ -192,7 +192,7 @@ static void
 DeflateResetInput(void)
 {
   InputState.seqno = 0;
-  InputState.dodgy_seqno = 0;
+  InputState.uncomp_rec = 0;
   inflateReset(&InputState.cx);
   LogPrintf(LogCCP, "Deflate: Input channel reset\n");
 }
@@ -214,7 +214,12 @@ DeflateInput(u_short *proto, struct mbuf *mi)
   seq = (hdr[0] << 8) + hdr[1];
   LogPrintf(LogDEBUG, "DeflateInput: Seq %d\n", seq);
   if (seq != InputState.seqno) {
-    if (InputState.dodgy_seqno && seq < InputState.seqno)
+    if (seq <= InputState.uncomp_rec)
+      /*
+       * So the peer's started at zero again - fine !  If we're wrong,
+       * inflate() will fail.  This is better than getting into a loop
+       * trying to get a ResetReq to a busy sender.
+       */
       InputState.seqno = seq;
     else {
       LogPrintf(LogERROR, "DeflateInput: Seq error: Got %d, expected %d\n",
@@ -225,7 +230,7 @@ DeflateInput(u_short *proto, struct mbuf *mi)
     }
   }
   InputState.seqno++;
-  InputState.dodgy_seqno = 0;
+  InputState.uncomp_rec = 0;
 
   /* Allocate an output mbuf */
   mo_head = mo = mballoc(DEFLATE_CHUNK_LEN, MB_IPIN);
@@ -420,6 +425,7 @@ DeflateDictSetup(u_short proto, struct mbuf *mi)
   CcpInfo.uncompin += len;
 
   InputState.seqno++;
+  InputState.uncomp_rec++;
   mbfree(mi_head);		/* lose our allocated ``head'' buf */
 }
 
@@ -533,13 +539,6 @@ DeflateInitInput(void)
   if (inflateInit2(&InputState.cx, -iWindowSize) != Z_OK)
     return 0;
   DeflateResetInput();
-  /*
-   * When we begin, we may start adding to our dictionary before the
-   * peer does.  If `dodgy_seqno' is set, we'll allow the peer to send
-   * us a seqno that's too small and just adjust seqno accordingly -
-   * deflate is a sliding window compressor !
-   */
-  InputState.dodgy_seqno = 1;
   return 1;
 }
 
diff --git a/usr.sbin/ppp/fsm.c b/usr.sbin/ppp/fsm.c
index caf4938fc35..32b2c053263 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 1.4 1997/12/24 09:30:31 brian Exp $
+ * $Id: fsm.c,v 1.5 1998/01/10 01:55:15 brian Exp $
  *
  *  TODO:
  *		o Refer loglevel for log output
@@ -724,18 +724,24 @@ FsmRecvTimeRemain(struct fsm * fp, struct fsmheader * lhp, struct mbuf * bp)
 static void
 FsmRecvResetReq(struct fsm * fp, struct fsmheader * lhp, struct mbuf * bp)
 {
-  LogPrintf(fp->LogLevel, "RecvResetReq\n");
+  LogPrintf(fp->LogLevel, "RecvResetReq(%d)\n", lhp->id);
   CcpRecvResetReq(fp);
-  LogPrintf(fp->LogLevel, "SendResetAck\n");
-  FsmOutput(fp, CODE_RESETACK, fp->reqid, NULL, 0);
+  /*
+   * All sendable compressed packets are queued in the PRI_NORMAL modem
+   * output queue.... dump 'em to the priority queue so that they arrive
+   * at the peer before our ResetAck.
+   */
+  SequenceQueues();
+  LogPrintf(fp->LogLevel, "SendResetAck(%d)\n", lhp->id);
+  FsmOutput(fp, CODE_RESETACK, lhp->id, NULL, 0);
   pfree(bp);
 }
 
 static void
 FsmRecvResetAck(struct fsm * fp, struct fsmheader * lhp, struct mbuf * bp)
 {
-  LogPrintf(fp->LogLevel, "RecvResetAck\n");
-  CcpResetInput();
+  LogPrintf(fp->LogLevel, "RecvResetAck(%d)\n", lhp->id);
+  CcpResetInput(lhp->id);
   fp->reqid++;
   pfree(bp);
 }
diff --git a/usr.sbin/ppp/fsm.h b/usr.sbin/ppp/fsm.h
index cd56347f049..8f17c7b588b 100644
--- a/usr.sbin/ppp/fsm.h
+++ b/usr.sbin/ppp/fsm.h
@@ -15,7 +15,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: fsm.h,v 1.2 1997/12/06 12:08:57 brian Exp $
+ * $Id: fsm.h,v 1.3 1998/01/10 01:55:15 brian Exp $
  *
  *	TODO:
  */
@@ -52,7 +52,7 @@ struct fsm {
   u_short max_code;
   int open_mode;
   int state;			/* State of the machine */
-  int reqid;			/* Next request id */
+  u_char reqid;			/* Next request id */
   int restart;			/* Restart counter value */
   int maxconfig;
 
diff --git a/usr.sbin/ppp/hdlc.c b/usr.sbin/ppp/hdlc.c
index e1c5a578df5..3f9b797d28a 100644
--- a/usr.sbin/ppp/hdlc.c
+++ b/usr.sbin/ppp/hdlc.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: hdlc.c,v 1.5 1998/01/06 01:03:01 brian Exp $
+ * $Id: hdlc.c,v 1.6 1998/01/10 01:55:16 brian Exp $
  *
  *	TODO:
  */
@@ -223,12 +223,13 @@ HdlcOutput(int pri, u_short proto, struct mbuf * bp)
     LqrChangeOrder(lqr, (struct lqrdata *) (MBUF_CTOP(bp)));
   }
   if (!DEV_IS_SYNC) {
-    fcs = HdlcFcs(INITFCS, MBUF_CTOP(mhp), mhp->cnt);
-    fcs = HdlcFcs(fcs, MBUF_CTOP(bp), bp->cnt);
+    mfcs->cnt = 0;
+    fcs = HdlcFcsBuf(INITFCS, mhp);
     fcs = ~fcs;
     cp = MBUF_CTOP(mfcs);
     *cp++ = fcs & 0377;		/* Low byte first!! */
     *cp++ = fcs >> 8;
+    mfcs->cnt = 2;
   }
   LogDumpBp(LogHDLC, "HdlcOutput", mhp);
   for (statp = ProtocolStat; statp->number; statp++)
@@ -381,11 +382,11 @@ DecodePacket(u_short proto, struct mbuf * bp)
    * If proto isn't PROTO_COMPD, we still want to pass it to the
    * decompression routines so that the dictionary's updated
    */
-  if (proto == PROTO_COMPD) {
-    if ((bp = CompdInput(&proto, bp)) == NULL)
-      return;
-  } else if ((proto & 0xfff1) == 0x21)		/* Network Layer protocol */
-    if (CcpFsm.state == ST_OPENED)
+  if (CcpFsm.state == ST_OPENED)
+    if (proto == PROTO_COMPD) {
+      if ((bp = CompdInput(&proto, bp)) == NULL)
+        return;
+    } else if ((proto & 0xfff1) == 0x21)	/* Network Layer protocol */
       CcpDictSetup(proto, bp);
 
   switch (proto) {
diff --git a/usr.sbin/ppp/modem.c b/usr.sbin/ppp/modem.c
index e4b8d98e95c..b1bb7808b4a 100644
--- a/usr.sbin/ppp/modem.c
+++ b/usr.sbin/ppp/modem.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: modem.c,v 1.7 1997/12/30 23:22:37 brian Exp $
+ * $Id: modem.c,v 1.8 1998/01/10 01:55:16 brian Exp $
  *
  *  TODO:
  */
@@ -94,7 +94,7 @@ Enqueue(struct mqueue * queue, struct mbuf * bp)
 }
 
 struct mbuf *
-Dequeue(struct mqueue * queue)
+Dequeue(struct mqueue *queue)
 {
   struct mbuf *bp;
 
@@ -112,6 +112,14 @@ Dequeue(struct mqueue * queue)
   return (bp);
 }
 
+void
+SequenceQueues()
+{
+  LogPrintf(LogDEBUG, "SequenceQueues\n");
+  while (OutputQueues[PRI_NORMAL].qlen)
+    Enqueue(OutputQueues + PRI_LINK, Dequeue(OutputQueues + PRI_NORMAL));
+}
+
 static struct speeds {
   int nspeed;
   speed_t speed;
diff --git a/usr.sbin/ppp/modem.h b/usr.sbin/ppp/modem.h
index 0fd81148090..7112096582d 100644
--- a/usr.sbin/ppp/modem.h
+++ b/usr.sbin/ppp/modem.h
@@ -15,7 +15,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: modem.h,v 1.1 1997/11/23 20:27:35 brian Exp $
+ * $Id: modem.h,v 1.2 1998/01/10 01:55:17 brian Exp $
  *
  *	TODO:
  */
@@ -38,5 +38,6 @@ extern void HangupModem(int);
 extern int ShowModemStatus(struct cmdargs const *);
 extern void Enqueue(struct mqueue *, struct mbuf *);
 extern struct mbuf *Dequeue(struct mqueue *);
+extern void SequenceQueues(void);
 extern void ModemAddInOctets(int);
 extern void ModemAddOutOctets(int);
diff --git a/usr.sbin/ppp/vars.c b/usr.sbin/ppp/vars.c
index ad3ddb5bf65..beb4cf451b5 100644
--- a/usr.sbin/ppp/vars.c
+++ b/usr.sbin/ppp/vars.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: vars.c,v 1.4 1997/12/29 22:23:08 brian Exp $
+ * $Id: vars.c,v 1.5 1998/01/10 01:55:17 brian Exp $
  *
  */
 #include <sys/param.h>
@@ -38,8 +38,8 @@
 #include "vars.h"
 #include "auth.h"
 
-char VarVersion[] = "PPP Version 1.5";
-char VarLocalVersion[] = "$Date: 1997/12/29 22:23:08 $";
+char VarVersion[] = "PPP Version 1.65";
+char VarLocalVersion[] = "$Date: 1998/01/10 01:55:17 $";
 int Utmp = 0;
 int ipInOctets = 0;
 int ipOutOctets = 0;