Fix data channel message integrity violation

SCTP message chunks and notifications are being delivered interleaved.
However, the way the code was structured previously, a notification
would interrupt reassembly of a message chunk and hand out the partial
message, thereby violating message integrity. This patch separates the
handling of notifications and reassembly of messages.

Additional changes:

- Remove illegal cast from non-validated u32 to enum (PPID)
- Drop partial messages if the SID has been changed but EOR not yet
  received instead of delivering them. (This should never happen
  anyway.)
- Don't treat TSN as timestamp (wat)

Bug: webrtc:11708
Change-Id: I4e2fe2262feda2a96d2ae3f6ce9b06370d9878ae
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/177527
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Taylor <deadbeef@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31605}

1 files changed, 1 insertions, 0 deletions

diff --git a/AUTHORS b/AUTHORS
index 188503e7f4..689220bb33 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -90,6 +90,7 @@ CZ Theng <cz.theng@gmail.com>
 Miguel Paris <mparisdiaz@gmail.com>
 Raman Budny <budnyjj@gmail.com>
 Stephan Hartmann <stha09@googlemail.com>
+Lennart Grahl <lennart.grahl@gmail.com>
 
 &yet LLC <*@andyet.com>
 8x8 Inc. <*@sip-communicator.org>