tree 1cc2e8ef33060e430b818d94202358e6325b37bf
parent e3e326d9f048a001bc848ca0638faf3d806e8b04
author Willy Tarreau <w@1wt.eu> 1485349942 +0100
committer Willy Tarreau <w@1wt.eu> 1485366361 +0100
encoding latin1

BUG/MEDIUM: tcp: don't poll for write when connect() succeeds

While testing a tcp_fastopen related change, it appeared that in the rare
case where connect() can immediately succeed, we still subscribe to write
notifications on the socket, causing the conn_fd_handler() to immediately
be called and a second call to connect() to be attempted to double-check
the connection.

In fact this issue had already been met with unix sockets (which often
respond immediately) and partially addressed but incorrect so another
patch will follow. But for TCP nothing was done.

The fix consists in removing the WAIT_L4_CONN flag if connect() succeeds
and to subscribe for writes only if some handshakes or L4_CONN are still
needed. In addition in order not to fail raw TCP health checks, we have
to continue to enable polling for data when nothing is scheduled for
leaving and the connection is already established, otherwise the caller
will never be notified.

This fix should be backported to 1.7 and 1.6.