[Pkg-privacy-commits] [obfs4proxy] 10/151: Remove support for Write deadlines since it wasn't working.

[Ximin Luo]

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infinity0 pushed a commit to branch master
in repository obfs4proxy.

commit 8a1f58cd5a1e2345b7321259c074c044a0ecbefd
Author: Yawning Angel <yawning at schwanenlied.me>
Date:   Mon May 12 02:37:40 2014 +0000

    Remove support for Write deadlines since it wasn't working.
    
    Write timeouts are obnoxious to handle as the frame encoder state
    already is updated to cover the entire payload for the Write() call
    that timed out.  In theory it is possible to buffer the pending data,
    but that causes Write() to voilate the semantics of the interface.
---
 obfs4.go | 37 +++++++++++++------------------------
 1 file changed, 13 insertions(+), 24 deletions(-)

diff --git a/obfs4.go b/obfs4.go
index d26d3e3..9a0fbbd 100644
--- a/obfs4.go
+++ b/obfs4.go
@@ -42,7 +42,7 @@ const (
 	defaultReadSize   = framing.MaximumSegmentLength
 	connectionTimeout = time.Duration(15) * time.Second
 
-	minCloseThreshold = framing.MaximumSegmentLength
+	minCloseThreshold = 0
 	maxCloseThreshold = framing.MaximumSegmentLength * 5
 	minCloseInterval  = 0
 	maxCloseInterval  = 60
@@ -199,8 +199,6 @@ func (c *Obfs4Conn) serverHandshake(nodeID *ntor.NodeID, keypair *ntor.Keypair)
 		return err
 	}
 
-	// TODO: Generate/send the PRNG seed.
-
 	err = c.conn.SetDeadline(time.Time{})
 	if err != nil {
 		return err
@@ -208,6 +206,8 @@ func (c *Obfs4Conn) serverHandshake(nodeID *ntor.NodeID, keypair *ntor.Keypair)
 
 	c.isOk = true
 
+	// TODO: Generate/send the PRNG seed.
+
 	return nil
 }
 
@@ -262,10 +262,7 @@ func (c *Obfs4Conn) Read(b []byte) (int, error) {
 			if err == framing.ErrAgain {
 				break
 			} else if err != nil {
-				// Any non-timeout frame decoder errors are fatal.
-				if neterr, ok := err.(net.Error); ok && !neterr.Timeout() {
-					c.isOk = false
-				}
+				// Any other frame decoder errors are fatal.
 				return 0, err
 			}
 
@@ -286,8 +283,6 @@ func (c *Obfs4Conn) Write(b []byte) (int, error) {
 	var frameBuf bytes.Buffer
 
 	for chopBuf.Len() > 0 {
-		// TODO: Support randomly padding frames.
-
 		// Send maximum sized frames.
 		n, err := chopBuf.Read(buf)
 		if err != nil {
@@ -312,13 +307,15 @@ func (c *Obfs4Conn) Write(b []byte) (int, error) {
 		nSent += n
 	}
 
-	// Send the frame.
+	// TODO: Insert random padding.
+
+	// Send the frame(s).
 	_, err := c.conn.Write(frameBuf.Bytes())
 	if err != nil {
-		// Non-timeout write errors as fatal.
-		if neterr, ok := err.(net.Error); ok && !neterr.Timeout() {
-			c.isOk = false
-		}
+		// Partial writes are fatal because the frame encoder state is advanced
+		// at this point.  It's possible to keep frameBuf around, but fuck it.
+		// Someone that wants write timeouts can change this.
+		c.isOk = false
 		return nSent, err
 	}
 
@@ -352,11 +349,7 @@ func (c *Obfs4Conn) RemoteAddr() net.Addr {
 }
 
 func (c *Obfs4Conn) SetDeadline(t time.Time) error {
-	if !c.isOk {
-		return syscall.EINVAL
-	}
-
-	return c.conn.SetDeadline(t)
+	return syscall.ENOTSUP
 }
 
 func (c *Obfs4Conn) SetReadDeadline(t time.Time) error {
@@ -368,11 +361,7 @@ func (c *Obfs4Conn) SetReadDeadline(t time.Time) error {
 }
 
 func (c *Obfs4Conn) SetWriteDeadline(t time.Time) error {
-	if !c.isOk {
-		return syscall.EINVAL
-	}
-
-	return c.conn.SetWriteDeadline(t)
+	return syscall.ENOTSUP
 }
 
 func Dial(network, address, nodeID, publicKey string) (net.Conn, error) {

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