[tor-bugs] #21314 [Circumvention/Snowflake]: snowflake-client needs to stop using my network when I'm not giving it requests

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#21314: snowflake-client needs to stop using my network when I'm not giving it
requests
-------------------------------------------------+-------------------------
 Reporter:  arma                                 |          Owner:  (none)
     Type:  defect                               |         Status:  new
 Priority:  Medium                               |      Milestone:
Component:  Circumvention/Snowflake              |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tor-pt, ex-sponsor19, anti-          |  Actual Points:
  censorship-roadmap                             |
Parent ID:  #21967                               |         Points:  2
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------

Comment (by dcf):

 I think the way to do this is to restructure the code so that the broker-
 polling loop (which keeps the client replenished with fresh proxies)
 happens inside the SOCKS handler, not outside.

 That is, currently the code works like this, with the broker-polling loop
 being global and independent of any SOCKS connection:
 {{{
 func main() {
     snowflakes := sf.NewPeers() // etc.
     go ConnectLoop(snowflakes) // start the background broker-polling loop

     for conn in ln.AcceptSocks() {
         // pass a handle to the snowflake collector to the handler
 function
         go Handler(conn, snowflakes)
     }

     snowflakes.End()
 }

 func Handler(socks net.Conn, snowflakes SnowflakeCollector) {
     snowflake := snowflakes.Pop()
     copyLoop(socks, snowflake)
 }
 }}}

 Instead, it should start a new browser-polling loop specific to each SOCKS
 connection (tor usually has 0 or 1 of these open at a time):
 {{{
 func main() {
     for conn in ln.AcceptSocks() {
         go Handler(conn)
     }
 }

 func Handler(socks net.Conn, snowflakes SnowflakeCollector) {
     snowflakes := sf.NewPeers() // etc.
     go ConnectLoop(snowflakes) // start the background broker-polling loop

     snowflake := snowflakes.Pop()
     copyLoop(socks, snowflake)

     snowflakes.End()
 }
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21314#comment:12>
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