From 2b31a9c49e8dab2955121a7d748f4a73837e4267 Mon Sep 17 00:00:00 2001
From: Maximilian Hils <git@maximilianhils.com>
Date: Sun, 27 Jul 2014 02:39:17 +0200
Subject: refactor tcp handling, fix #280

---
 libmproxy/protocol/tcp.py | 69 +++++++++++++++++++++++++----------------------
 1 file changed, 37 insertions(+), 32 deletions(-)

(limited to 'libmproxy/protocol/tcp.py')

diff --git a/libmproxy/protocol/tcp.py b/libmproxy/protocol/tcp.py
index 6cdc6581..33c9ff05 100644
--- a/libmproxy/protocol/tcp.py
+++ b/libmproxy/protocol/tcp.py
@@ -1,16 +1,21 @@
 from __future__ import absolute_import
 import select, socket
-from cStringIO import StringIO
 from .primitives import ProtocolHandler
 
-
 class TCPHandler(ProtocolHandler):
     """
     TCPHandler acts as a generic TCP forwarder.
     Data will be .log()ed, but not stored any further.
     """
+
+    chunk_size = 4096
+
     def handle_messages(self):
         self.c.establish_server_connection()
+
+        server = "%s:%s" % self.c.server_conn.address()[:2]
+        buf = memoryview(bytearray(self.chunk_size))
+
         conns = [self.c.client_conn.rfile, self.c.server_conn.rfile]
         while not self.c.close:
             r, _, _ = select.select(conns, [], [], 10)
@@ -18,43 +23,43 @@ class TCPHandler(ProtocolHandler):
                 if self.c.client_conn.rfile == rfile:
                     src, dst = self.c.client_conn, self.c.server_conn
                     direction = "-> tcp ->"
-                    dst_str = "%s:%s" % self.c.server_conn.address()[:2]
+                    src_str, dst_str = "client", server
                 else:
                     dst, src = self.c.client_conn, self.c.server_conn
                     direction = "<- tcp <-"
-                    dst_str = "client"
-
-                data = StringIO()
-                while range(4096):
-                    # Do non-blocking select() to see if there is further data on in the buffer.
-                    r, _, _ = select.select([rfile], [], [], 0)
-                    if len(r):
-                        d = rfile.read(1)
-                        if d == "":  # connection closed
-                            break
-                        data.write(d)
-                        # OpenSSL Connections have an internal buffer that might
-                        # contain data altough everything is read from the socket.
-                        # Thankfully, connection.pending() returns the amount of
-                        # bytes in this buffer, so we can read it completely at
-                        # once.
-                        if src.ssl_established:
-                            data.write(rfile.read(src.connection.pending()))
-                    else:  # no data left, but not closed yet
-                        break
-                data = data.getvalue()
-
-                if data == "":  # no data received, rfile is closed
-                    self.c.log("Close writing connection to %s" % dst_str, "debug")
-                    conns.remove(rfile)
+                    dst_str, src_str = "client", server
+
+                closed = False
+                if src.ssl_established:
+                    # Unfortunately, pyOpenSSL lacks a recv_into function.
+                    contents = src.rfile.read(1)  # We need to read a single byte before .pending() becomes usable
+                    contents += src.rfile.read(src.connection.pending())
+                    if not contents:
+                        closed = True
+                else:
+                    size = src.connection.recv_into(buf)
+                    if not size:
+                        closed = True
+
+                if closed:
+                    conns.remove(src.rfile)
+                    # Shutdown connection to the other peer
                     if dst.ssl_established:
                         dst.connection.shutdown()
                     else:
                         dst.connection.shutdown(socket.SHUT_WR)
+
                     if len(conns) == 0:
                         self.c.close = True
-                    break
+                    continue
 
-                self.c.log("%s %s\r\n%s" % (direction, dst_str, data), "debug")
-                dst.wfile.write(data)
-                dst.wfile.flush()
+                if src.ssl_established or dst.ssl_established:
+                    # if one of the peers is over SSL, we need to send bytes/strings
+                    if not src.ssl_established:  # only ssl to dst, i.e. we revc'd into buf but need bytes/string now.
+                        contents = buf[:size].tobytes()
+                    self.c.log("%s %s\r\n%s" % (direction, dst_str, contents[:100]), "debug")
+                    dst.connection.send(contents)
+                else:
+                    # socket.socket.send supports raw bytearrays/memoryviews
+                    self.c.log("%s %s\r\n%s" % (direction, dst_str, buf[:100]), "debug")
+                    dst.connection.send(buf[:size])
\ No newline at end of file
-- 
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