[Heimdal-source-changes] [heimdal/heimdal] af018a: Don't stutter in send_diffs

[Nico Williams]

  Branch: refs/heads/heimdal-7-1-branch
  Home:   https://github.com/heimdal/heimdal
  Commit: af018a5aead8b391351ba71bbb85662f780a9a2a
      https://github.com/heimdal/heimdal/commit/af018a5aead8b391351ba71bbb85662f780a9a2a
  Author: Viktor Dukhovni <viktor at twosigma.com>
  Date:   2019-09-14 (Sat, 14 Sep 2019)

  Changed paths:
    M lib/kadm5/ipropd_master.c

  Log Message:
  -----------
  Don't stutter in send_diffs

When the master sees a burst of updates (perhaps sustained), the
slaves "I_HAVE" messages can fall behind the version we've already
sent, and the unpatched code would retransmit already sent diffs!

This can result in substantial amplification (in a local test, 3000
ops turned into 427,000 ops).  Though the number of *messages* sent
was actually somewhat smaller, the ever growing message size
ultimately leads to failure.