When talking to a SOCKS v5 proxy, default to sending addresses as raw domains rather than IP addresses.

Before, we would default to client-side DNS resolution (sending IP addresses to the proxy) for both v4 and v5. However if you are using a v5 server, it is most likely that you want to do the resolves on the proxy-side. And in fact if you are using a SOCKS 5 proxy to anonymize your browsing, you definitely don't want that as the default policy.

Embedders of the network stack can select the alternate policy by passing a non-NULL Host resolver into SOCKS5ClientSocket.

BUG=29914
TEST=HttpNetworkTransactionTest.SOCKS5_HTTP_GET, HttpNetworkTransactionTest.SOCKS5_SSL_GET

Review URL: http://codereview.chromium.org/507033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@34903 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 19 insertions, 2 deletions

diff --git a/net/socket/socks5_client_socket.h b/net/socket/socks5_client_socket.h
index a5db645..9a05f4a 100644
--- a/net/socket/socks5_client_socket.h
+++ b/net/socket/socks5_client_socket.h
@@ -31,6 +31,21 @@ class SOCKS5ClientSocket : public ClientSocket {
   //
   // |req_info| contains the hostname and port to which the socket above will
   // communicate to via the SOCKS layer.
+  //
+  // SOCKS5 supports three modes of specifying connection endpoints:
+  //  (1) as an IPv4 address.
+  //  (2) as an IPv6 address.
+  //  (3) as a hostname string.
+  //
+  // To select mode (3), pass NULL for |host_resolver|.
+  //
+  // Otherwise if a non-NULL |host_resolver| is given, Connect() will first
+  // try to resolve the hostname using |host_resolver|, and pass that
+  // resolved address to the proxy server. If the resolve failed, Connect()
+  // will fall-back to mode (3) and simply send the unresolved hosname string
+  // to the SOCKS v5 proxy server.
+  //
+  // Passing NULL for |host_resolver| is the recommended default.
   SOCKS5ClientSocket(ClientSocket* transport_socket,
                      const HostResolver::RequestInfo& req_info,
                      HostResolver* host_resolver);
@@ -142,8 +157,10 @@ class SOCKS5ClientSocket : public ClientSocket {
 
   size_t read_header_size;
 
-  // Used to resolve the hostname to which the SOCKS proxy will connect.
-  SingleRequestHostResolver host_resolver_;
+  // If non-NULL, we will use this host resolver to resolve DNS client-side
+  // (and fall back to proxy-side resolving if it fails).
+  // Otherwise, we will do proxy-side DNS resolving.
+  scoped_ptr<SingleRequestHostResolver> host_resolver_;
   AddressList addresses_;
   HostResolver::RequestInfo host_request_info_;