So the assignment of proxies is based on the load. The number of clients
is ronded down to 8. Existing proxies that doesn't report the number
of clients will be distributed equaly to new proxies until they get 8
clients, that is okish as the existing proxies do have a maximum
capacity of 10.
Fixes#40048
Update our dependency on pion/sdp from v2 to v3, to match pion/webrtc
v3. This requires some changes in how we parse out addresses from ice
candidates. This will ease tor browser builds of snowflake since we are
now only relying on one version of pion/sdp instead of two different
ones.
This update required two main changes to how we use the library. First,
we had to make sure we created the datachannel on the offering peer side
before creating the offer. Second, we had to make sure we wait for the
gathering of all candidates to complete since trickle-ice is enabled by
default. See the release notes for more details:
https://github.com/pion/webrtc/wiki/Release-WebRTC@v3.0.0.
Rather than having standalone proxies determine their NAT type by
conducting the NAT behaviour checks in RFC 5780, use the remote probe
service instead.
We expect one of these at the end of just about every proxy session, as
the Conns in both directions are closed as soon as the copy loop
finishes in one direction.
Closes#40016.
The client and proxy use the net/http default transport to make round
trip connecitons to the broker. These by default don't time out and can
wait indefinitely for the broker to respond if the broker hangs and
doesn't terminate the connection.
This will allow browser-based proxies that are unable to determine their
NAT type to conservatively label themselves as restricted NATs if they
fail to work with clients that have restricted NATs.
Switch to containing all communication between the proxy and the broker
in the HTTP response body. This will make things easier if we ever use
something other than HTTP communicate between different actors in the
snowflake system.
Other changes to the protocol are as follows:
- requests are accompanied by a version number so the broker can be
backwards compatable if desired in the future
- all responses are 200 OK unless the request was badly formatted
The variable maxNumClients was unused, while connectionsPerClient was
used for spawning multiple proxyPairs. The former is a more appropriate
name for the multiplexing behaviour we use it for.
Multiplexing now just works thanks to implementing ticket #31310.
We don't need it, and already have a function webrtcIsReady that tells
us what we need to know (whether a datachannel was opened before the
timeout period).
The only place it was used was in window.onpageunload, and we have a
better way of determining if the proxy is active there (through the ui).
I also removed that code from the webextension since the proxy won't
stop running unless you close the browser and after testing it looks
like that code doesn't notify the user anyway.
