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.

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!

1 files changed, 12 insertions, 6 deletions

diff --git a/usr.sbin/ppp/fsm.c b/usr.sbin/ppp/fsm.c
index 3a949f7..1dd5bef 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 1.24 1997/12/13 02:37:23 brian Exp $
+ * $Id: fsm.c,v 1.25 1997/12/24 09:28:58 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);
 }