Correctly handle FTP servers which unexpectedly close the control connection.

net/ftp/ftp_network_transaction.cc

Index: net/ftp/ftp_network_transaction.cc
diff --git a/net/ftp/ftp_network_transaction.cc b/net/ftp/ftp_network_transaction.cc
index 03a12916a38e6b58363dc46befb22298e996ac82..a4d0a734a0087d8a760441bb764565b921349f14 100644
--- a/net/ftp/ftp_network_transaction.cc
+++ b/net/ftp/ftp_network_transaction.cc
@@ -522,6 +522,14 @@ int FtpNetworkTransaction::DoCtrlRead() {
 }
 
 int FtpNetworkTransaction::DoCtrlReadComplete(int result) {
+  if (result == 0) {
+    // Some servers (for example Pure-FTPd) apparently close the control
+    // connection when anonymous login is not permitted. For more details
+    // see http://crbug.com/25023.
+    if (command_sent_ == COMMAND_USER && username_ == L"anonymous")
+      response_.needs_auth = true;
+    return Stop(ERR_EMPTY_RESPONSE);

[wtc, 2009/10/31 15:16:48]

I think ERR_EMPTY_RESPONSE is fine.  We can also add an
FTP error code for this condition (ERR_FTP_CONTROL_CONNECTION_CLOSED?).

+  }
   if (result < 0)
     return Stop(result);