archives/snowflake
2
0
Fork 0
mirror of https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake.git synced 2025-10-13 11:11:30 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

improvement: use SetIPFilter for local addrs

Browse source 
Closes https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/40271.
Supersedes https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/merge_requests/417.

This simplifies the code and (probably) removes the need for
`StripLocalAddresses`, although makes us more dependent on Pion.

Signed-off-by: Cecylia Bocovich <cohosh@torproject.org>
This commit is contained in:
WofWca 2024-11-25 01:43:29 +04:00 • committed by Cecylia Bocovich
parent 43799819a1
commit ae5bd52821
No known key found for this signature in database
GPG key ID: 009DE379FD9B7B90
6 changed files with 56 additions and 32 deletions
Download patch file Download diff file Expand all files Collapse all files

9
client/lib/rendezvous.go
View file

@ -127,15 +127,6 @@ func newBrokerChannelFromConfig(config ClientConfig) (*BrokerChannel, error) {
func (bc *BrokerChannel) Negotiate(offer *webrtc.SessionDescription) (
*webrtc.SessionDescription, error,
) {
// Ideally, we could specify an `RTCIceTransportPolicy` that would handle
// this for us. However, "public" was removed from the draft spec.
// See https://developer.mozilla.org/en-US/docs/Web/API/RTCConfiguration#RTCIceTransportPolicy_enum
if !bc.keepLocalAddresses {
offer = &webrtc.SessionDescription{
Type: offer.Type,
SDP: util.StripLocalAddresses(offer.SDP),
}
}
offerSDP, err := util.SerializeSessionDescription(offer)
if err != nil {
return nil, err

24
client/lib/webrtc.go
View file

@ -6,6 +6,7 @@ import (
"errors"
"io"
"log"
"net"
"net/url"
"sync"
"time"
@ -17,6 +18,7 @@ import (
"gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/v2/common/event"
"gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/v2/common/proxy"
"gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/v2/common/util"
)
// WebRTCPeer represents a WebRTC connection to a remote snowflake proxy.
@ -166,7 +168,8 @@ func (c *WebRTCPeer) checkForStaleness(timeout time.Duration) {
// receive an answer from broker, and wait for data channel to open
func (c *WebRTCPeer) connect(config *webrtc.Configuration, broker *BrokerChannel) error {
log.Println(c.id, " connecting...")
err := c.preparePeerConnection(config)
err := c.preparePeerConnection(config, broker.keepLocalAddresses)
localDescription := c.pc.LocalDescription()
c.eventsLogger.OnNewSnowflakeEvent(event.EventOnOfferCreated{
WebRTCLocalDescription: localDescription,
@ -207,10 +210,25 @@ func (c *WebRTCPeer) connect(config *webrtc.Configuration, broker *BrokerChannel
// preparePeerConnection creates a new WebRTC PeerConnection and returns it
// after non-trickle ICE candidate gathering is complete.
func (c *WebRTCPeer) preparePeerConnection(config *webrtc.Configuration) error {
func (c *WebRTCPeer) preparePeerConnection(
config *webrtc.Configuration,
keepLocalAddresses bool,
) error {
var err error
s := webrtc.SettingEngine{}
s.SetICEMulticastDNSMode(ice.MulticastDNSModeDisabled)
if !keepLocalAddresses {
s.SetIPFilter(func(ip net.IP) (keep bool) {
// `IsLoopback()` and `IsUnspecified` are likely not neded here,
// but let's keep them just in case.
// FYI there is similar code in other files in this project.
keep = !util.IsLocal(ip) && !ip.IsLoopback() && !ip.IsUnspecified()
return
})
s.SetICEMulticastDNSMode(ice.MulticastDNSModeDisabled)
}
s.SetIncludeLoopbackCandidate(keepLocalAddresses)
// Use the SetNet setting https://pkg.go.dev/github.com/pion/webrtc/v3#SettingEngine.SetNet
// to get snowflake working in shadow (where the AF_NETLINK family is not implemented).
// These two lines of code functionally revert a new change in pion by silently ignoring