[tor-bugs] #33666 [Circumvention/Snowflake]: Investigate Snowflake proxy failures

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#33666: Investigate Snowflake proxy failures
-------------------------------------+------------------------------
 Reporter:  cohosh                   |          Owner:  (none)
     Type:  defect                   |         Status:  needs_review
 Priority:  High                     |      Milestone:
Component:  Circumvention/Snowflake  |        Version:
 Severity:  Normal                   |     Resolution:
 Keywords:                           |  Actual Points:
Parent ID:  #19001                   |         Points:
 Reviewer:                           |        Sponsor:
-------------------------------------+------------------------------
Changes (by cohosh):

 * status:  new => needs_review


Comment:

 Here's a patch that implements a variation of option (2) above. If the
 proxy fails to open a datachannel more than a threshold number of times
 since the last success, it is disabled with a new missingFeatures message.

 https://github.com/cohosh/snowflake/pull/25

 Let's get some feedback on this idea before moving further.

 I tested this by applying the following patch to the client:
 {{{
 diff --git a/client/lib/rendezvous.go b/client/lib/rendezvous.go
 index 1f98e26..330c90a 100644
 --- a/client/lib/rendezvous.go
 +++ b/client/lib/rendezvous.go
 @@ -11,6 +11,7 @@ package lib
  import (
         "bytes"
         "errors"
 +       "fmt"
         "io"
         "io/ioutil"
         "log"
 @@ -119,8 +120,8 @@ func (bc *BrokerChannel) Negotiate(offer
 *webrtc.SessionDescription) (
                 if nil != err {
                         return nil, err
                 }
 -               answer := util.DeserializeSessionDescription(string(body))
 -               return answer, nil
 +               util.DeserializeSessionDescription(string(body))
 +               return nil, fmt.Errorf("Dummy error")
         case http.StatusServiceUnavailable:
                 return nil, errors.New(BrokerError503)
         case http.StatusBadRequest:
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33666#comment:6>
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