mirror of
https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake.git
synced 2025-10-13 11:11:30 -04:00
904af9cb8a
Formerly we waiting until *both* directions finished. What this meant in practice is that when the remote connection ended, copyLoop would become useless but would continue blocking its caller until something else finally closed the socks connection.
58 lines
1.4 KiB
Go
58 lines
1.4 KiB
Go
package lib
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import (
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"errors"
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"io"
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"log"
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"net"
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"time"
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)
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const (
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ReconnectTimeout = 10 * time.Second
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SnowflakeTimeout = 30 * time.Second
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)
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// Given an accepted SOCKS connection, establish a WebRTC connection to the
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// remote peer and exchange traffic.
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func Handler(socks net.Conn, snowflakes SnowflakeCollector) error {
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// Obtain an available WebRTC remote. May block.
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snowflake := snowflakes.Pop()
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if nil == snowflake {
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return errors.New("handler: Received invalid Snowflake")
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}
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defer snowflake.Close()
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log.Println("---- Handler: snowflake assigned ----")
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go func() {
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// When WebRTC resets, close the SOCKS connection too.
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snowflake.WaitForReset()
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socks.Close()
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}()
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// Begin exchanging data. Either WebRTC or localhost SOCKS will close first.
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// In eithercase, this closes the handler and induces a new handler.
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copyLoop(socks, snowflake)
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log.Println("---- Handler: closed ---")
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return nil
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}
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// Exchanges bytes between two ReadWriters.
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// (In this case, between a SOCKS and WebRTC connection.)
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func copyLoop(socks, webRTC io.ReadWriter) {
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done := make(chan struct{}, 2)
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go func() {
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if _, err := io.Copy(socks, webRTC); err != nil {
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log.Printf("copying WebRTC to SOCKS resulted in error: %v", err)
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}
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done <- struct{}{}
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}()
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go func() {
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if _, err := io.Copy(webRTC, socks); err != nil {
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log.Printf("copying SOCKS to WebRTC resulted in error: %v", err)
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}
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done <- struct{}{}
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}()
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<-done
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log.Println("copy loop ended")
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}
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