Uploaded image for project: 'Traffic Server'
  1. Traffic Server
  2. TS-3456

SSL blind tunnel sometimes not created


    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 6.0.0
    • Component/s: Plugins, SSL
    • Labels:



      I made a simple plugin that sets up TS_SSL_SNI_HOOK and creates a
      blind tunnel from a separate thread. With low load everything works
      fine, but with moderate load (100 simultaneous users, each user sends
      200 HTTPS requests) I see somewhat strange behavior.

      On a client side I use Tsung, which creates users and sends number of
      requests per user. For each user Tsung waits for a response before
      sending a new request, so if response never arrives, a particular user
      (and the whole test) stalls.

      So, with load mentioned above I see few 'stalled' connections on both
      client and proxy – netstat shows them as ”established”, ATS seems to
      have data structures for those (checked
      proxy.process.net.connections_currently_open value), but no traffic
      goes between proxy and client.

      Client side (.175):

      tcp 0 0 ESTABLISHED 14332/beam.smp
      (more similar connections here)

      Proxy side (.250 is a server):
      tcp 0 0 ESTABLISHED 28117/traffic_serve
      (more similar connections here)

      I checked traffic.out log and found out that
      ”SSLNextProtocolAccept:mainEvent” does not get called as many times as
      it should. This can probably be explained by the fact that client does
      not send requests for given user anymore if response to previous
      request hasn't been received. Which, in turn, may indicate that at
      some point tunnel has not been created.

      The interesting thing is that everything works fine if a tunnel is
      created directly from TS_SSL_SNI_HOOK but not from the separate

      The plugin code is very simple – I set up TS_SSL_SNI_HOOK and start a
      thread with TSThreadCreate. When hook got called, I push TSVConn to a
      thread-safe queue. The thread wakes up when item has been pushed,
      calls TSVConnTunnel / TSVConnReenable for given vconn and then waits
      for the next item. I have attached the code.


        1. ts-tls.cc
          2 kB
          Lev Stipakov
        2. ts-3456-2.diff
          1 kB
          Susan Hinrichs



            • Assignee:
              shinrich Susan Hinrichs
              lstipakov Lev Stipakov
            • Votes:
              0 Vote for this issue
              3 Start watching this issue


              • Created: