Don't support bidirectional shutdown over DTLS.

Bidirectional shutdown doesn't make sense over DTLS; you can't reuse the
underlying channel after receiving close_notify because the channel is
unordered. This removes one caller of dtls1_read_bytes.

Really close_notify makes no sense in DTLS. It can't even protect
against some kind of truncation because it's all unordered. But continue
to send it in case anything is (unreliably since the channel is lossy)
relying on close_notify to signal some kind of session end. This only
makes SSL_shutdown stop trying to wait for one once we've already
decided to shut down the connection.

BUG=526437

Change-Id: I6afad7cb7209c4aba0b96f9246b04c81d90987a9
Reviewed-on: https://boringssl-review.googlesource.com/5770
Reviewed-by: Adam Langley <agl@google.com>
1 file changed