Websocket to TCP proxy running in a separate thread (only on ChromeOS).

chrome/browser/chromeos/net/webproxy/conn.h

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_CHROMEOS_NET_WEBPROXY_CONN_H_
+#define CHROME_BROWSER_CHROMEOS_NET_WEBPROXY_CONN_H_
+
+#include <sys/socket.h>
+
+#include "base/md5.h"
+#include "chrome/browser/chromeos/net/webproxy/serv.h"
+#include "third_party/libevent/event.h"
+
+namespace chromeos {
+namespace webproxy {
+
+class Conn {

[zel, 2011/04/07 16:54:12]

comments please - what does this class do?

[Denis Lagno, 2011/04/11 23:21:27]

Done.

+ public:
+  enum Phase {
+    // Initial stage of connection.
+    PHASE_WAIT_HANDSHAKE,
+    PHASE_WAIT_DESTFRAME,
+    PHASE_WAIT_DESTCONNECT,
+
+    // Operational stage of connection.
+    PHASE_OUTSIDE_FRAME,
+    PHASE_INSIDE_FRAME_BASE64,
+    PHASE_INSIDE_FRAME_SKIP,
+
+    // Terminal stage of connection.
+    PHASE_SHUT,    // Closing handshake was emitted, buffers may pending.
+    PHASE_DEFUNCT  // Connection was nuked.
+  };
+
+  // Channel structure.
+  struct Chan {
+    int sock;
+    struct bufferevent* bev;
+
+    Chan() : sock(-1), bev(NULL) {}
+
+    ~Chan() {
+      if (bev) {
+        bufferevent_disable(bev, EV_READ | EV_WRITE);
+        bufferevent_free(bev);
+        bev = NULL;
+      }
+      if (sock >= 0) {
+        shutdown(sock, SHUT_RDWR);
+        close(sock);
+        sock = -1;
+      }
+    }
+  };
+
+  // Status of processing incoming data.
+  enum Status {
+    STATUS_OK,
+    STATUS_INCOMPLETE,  // Not all required data is present in buffer yet.
+    STATUS_SKIP,
+    STATUS_ABORT        // Data is invalid.  We must shut connection.
+  };
+
+  // Unfortunately evdns callbacks are uncancellable,
+  // so potentially we can receive callback for a deleted Conn.
+  // Even worse, storage of deleted Conn may be reused
+  // for a new connection and new connection can receive callback
+  // destined for deleted Conn.
+  // Conn::Token is introduced in order to prevent that.
+  typedef void* Token;
+  typedef std::map<Token, Conn*> TokenMap;
+
+  explicit Conn(Serv* master);
+  ~Conn();
+
+  static Conn* Get(Token token);
+
+  void Shut();
+
+  Status ConsumeHeader(struct evbuffer*);
+  Status ConsumeDestframe(struct evbuffer*);
+  Status ConsumeFrameHeader(struct evbuffer*);
+  Status ProcessFrameData(struct evbuffer*);
+
+  // Returns true on success.
+  bool EmitHandshake(struct bufferevent*);
+
+  // Attempts to establish second connection (to remote TCP service).
+  // Returns true on success.
+  bool TryConnectDest(const struct sockaddr*, socklen_t);
+
+  // Used as libevent callbacks.
+  static void OnDestConnectTimeout(int, short, Token);
+  static void OnPrimchanRead(struct bufferevent*, Token);
+  static void OnPrimchanWrite(struct bufferevent*, Token);
+  static void OnPrimchanError(struct bufferevent*, short what, Token);
+  static void OnDestResolutionIPv4(int result, char type, int count,
+                                   int ttl, void* addr_list, Token);
+  static void OnDestResolutionIPv6(int result, char type, int count,
+                                   int ttl, void* addr_list, Token);
+  static void OnDestchanRead(struct bufferevent*, Token);
+  static void OnDestchanWrite(struct bufferevent*, Token);
+  static void OnDestchanError(struct bufferevent*, short what, Token);
+
+  Chan& primchan() { return primchan_; }
+  Token token() const { return token_; }
+
+ private:
+  Serv* master_;
+  Phase phase_;
+
+  // We maintain two channels per Conn:
+  // primary channel is websocket connection.
+  Chan primchan_;
+  // Destination channel is a proxied connection.
+  Chan destchan_;
+
+  Token token_;
+
+  // Header fields supplied by client at initial websocket handshake.
+  std::map<std::string, std::string> header_fields_;
+
+  // Cryptohashed answer for websocket handshake.
+  MD5Digest handshake_response_;
+
+  // Hostname and port of destination socket.
+  // Websocket client supplies them in first data frame (destframe).
+  std::string destname_;
+  uint32 destport_;
+
+  // We try to DNS resolve hostname in both IPv4 and IPv6 domains.
+  // Track resolution failures here.
+  bool destresolution_ipv4_failed_;
+  bool destresolution_ipv6_failed_;
+
+  // Used to schedule a timeout for an initial phase of connection.
+  struct event destconnect_timeout_event_;
+
+  static TokenMap token_map_;
+  static Token last_token_;
+
+  DISALLOW_COPY_AND_ASSIGN(Conn);
+};
+
+}  // namespace chromeos
+}  // namespace webproxy
+
+#endif  // CHROME_BROWSER_CHROMEOS_NET_WEBPROXY_CONN_H_