commit 114df695ceff25d0213200a3368ed7a1bb1c7668
Author: Cecylia Bocovich <[email protected]>
Date: Mon Nov 23 14:02:54 2020 -0500
Create new smux session for each SOCKS connection
Each SOCKS connection has its own set of snowflakes and broker poll
loop. Since the session manager was tied to a single set of snowflakes,
this resulted in a bug where RedialPacketConn would sometimes try to
pull snowflakes from a previously melted pool. The fix is to maintain
separate smux sessions for each SOCKS connection, tied to its own
snowflake pool.
---
client/lib/snowflake.go | 57 ++++++-------------------------------------------
1 file changed, 6 insertions(+), 51 deletions(-)
diff --git a/client/lib/snowflake.go b/client/lib/snowflake.go
index e888160..171e173 100644
--- a/client/lib/snowflake.go
+++ b/client/lib/snowflake.go
@@ -6,7 +6,6 @@ import (
"io"
"log"
"net"
- "sync"
"time"
"git.torproject.org/pluggable-transports/snowflake.git/common/turbotunnel"
@@ -92,54 +91,6 @@ func newSession(snowflakes SnowflakeCollector)
(net.PacketConn, *smux.Session, e
return pconn, sess, err
}
-// sessionManager_ maintains a single global smux.Session that is shared among
-// incoming SOCKS connections.
-type sessionManager_ struct {
- mutex sync.Mutex
- sess *smux.Session
-}
-
-// Get creates and returns a new global smux.Session if none exists yet. If one
-// already exists, it returns the existing one. It monitors the returned
session
-// and if it ever fails, sets things up so the next call to Get will create a
-// new session.
-func (manager *sessionManager_) Get(snowflakes SnowflakeCollector)
(*smux.Session, error) {
- manager.mutex.Lock()
- defer manager.mutex.Unlock()
-
- if manager.sess == nil {
- log.Printf("starting a new session")
- pconn, sess, err := newSession(snowflakes)
- if err != nil {
- return nil, err
- }
- manager.sess = sess
- go func() {
- // If the session dies, set it to be recreated.
- for {
- <-time.After(5 * time.Second)
- if sess.IsClosed() {
- break
- }
- }
- log.Printf("discarding finished session")
- // Close the underlying to force any ongoing WebRTC
- // connection to close as well, and relinquish the
- // SnowflakeCollector.
- pconn.Close()
- manager.mutex.Lock()
- manager.sess = nil
- manager.mutex.Unlock()
- }()
- } else {
- log.Printf("reusing the existing session")
- }
-
- return manager.sess, nil
-}
-
-var sessionManager = sessionManager_{}
-
// Given an accepted SOCKS connection, establish a WebRTC connection to the
// remote peer and exchange traffic.
func Handler(socks net.Conn, tongue Tongue) error {
@@ -155,8 +106,9 @@ func Handler(socks net.Conn, tongue Tongue) error {
log.Printf("---- Handler: begin collecting snowflakes ---")
go connectLoop(snowflakes)
- // Return the global smux.Session.
- sess, err := sessionManager.Get(snowflakes)
+ // Create a new smux session
+ log.Printf("---- Handler: starting a new session ---")
+ pconn, sess, err := newSession(snowflakes)
if err != nil {
return err
}
@@ -174,6 +126,9 @@ func Handler(socks net.Conn, tongue Tongue) error {
log.Printf("---- Handler: closed stream %v ---", stream.ID())
snowflakes.End()
log.Printf("---- Handler: end collecting snowflakes ---")
+ pconn.Close()
+ sess.Close()
+ log.Printf("---- Handler: discarding finished session ---")
return nil
}
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