Karl M added the CURLOPT_CONNECT_ONLY and CURLINFO_LASTSOCKET options that

an app can use to let libcurl only connect to a remote host and then extract
the socket from libcurl. libcurl will then not attempt to do any transfer at
all after the connect is done.

13 files changed, 115 insertions, 44 deletions

diff --git a/CHANGES b/CHANGES
index 88961d32d..826b02100 100644
--- a/CHANGES
+++ b/CHANGES
@@ -7,6 +7,11 @@
                                   Changelog
 
 Daniel (11 February 2006)
+- Karl M added the CURLOPT_CONNECT_ONLY and CURLINFO_LASTSOCKET options that
+  an app can use to let libcurl only connect to a remote host and then extract
+  the socket from libcurl. libcurl will then not attempt to do any transfer at
+  all after the connect is done.
+
 - Kent Boortz improved the configure check for GnuTLS to properly set LIBS
   instead of LDFLAGS.
 
diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index d7babaab2..5cd89a464 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -2,21 +2,22 @@ Curl and libcurl 7.15.2
 
  Public curl release number:               92
  Releases counted from the very beginning: 119
- Available command line options:           109
- Available curl_easy_setopt() options:     125
+ Available command line options:           111
+ Available curl_easy_setopt() options:     129
  Number of public functions in libcurl:    46
- Amount of public web site mirrors:        30
+ Amount of public web site mirrors:        31
  Number of known libcurl bindings:         32
  Number of contributors:                   474
 
 This release includes the following changes:
 
+ o CURLOPT_CONNECT_ONLY and CURLINFO_LASTSOCKET added
  o CURLOPT_LOCALPORT and CURLOPT_LOCALPORTRANGE (--local-port) added
  o Dropped support for the LPRT ftp command
- o Gopher is now officially abandoned as a protocol (lib)curl tries to support.
+ o Gopher is now officially abandoned as a protocol (lib)curl tries to support
  o curl_global_init() and curl_global_cleanup() are now using a refcount so
    that it is now legal to call them multiple times. See updated info for
-   details.
+   details
 
 This release includes the following bugfixes:
 
@@ -60,7 +61,7 @@ advice from friends like these:
 
  Dov Murik, Jean Jacques Drouin, Andres Garcia, Yang Tse, Gisle Vanem, Dan
  Fandrich, Alexander Lazic, Michael Jahn, Andrew Benham, Bryan Henderson,
- David Shaw, Jon Turner, Duane Cathey, Michal Marek, Philippe Vaucher,
- Kent Boortz
+ David Shaw, Jon Turner, Duane Cathey, Michal Marek, Philippe Vaucher, Kent
+ Boortz, Karl M
  
         Thanks! (and sorry if I forgot to mention someone)
diff --git a/docs/libcurl/curl_easy_getinfo.3 b/docs/libcurl/curl_easy_getinfo.3
index bc4f2063b..2119ea211 100644
--- a/docs/libcurl/curl_easy_getinfo.3
+++ b/docs/libcurl/curl_easy_getinfo.3
@@ -141,6 +141,12 @@ cookies cURL knows (expired ones, too). Don't forget to
 cookies (cookies for the handle have not been enabled or simply none have been
 received) 'struct curl_slist *' will be set to point to NULL. (Added in
 7.14.1)
+.IP CURLINFO_LASTSOCKET
+Pass a pointer to a long to receive the last socket used by this curl
+session. If the socket is no longer valid, -1 is returned. When you finish
+working with the socket, you must call curl_easy_cleanup() as usual and let
+libcurl close the socket and cleanup other resources associated with the
+handle. (Added in 7.15.2)
 .SH TIMES
 .NF
 An overview of the six time values available from curl_easy_getinfo()
diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3
index 25e7e7707..8a152947c 100644
--- a/docs/libcurl/curl_easy_setopt.3
+++ b/docs/libcurl/curl_easy_setopt.3
@@ -1044,6 +1044,14 @@ Resolve to ipv4 addresses.
 .IP CURL_IPRESOLVE_V6
 Resolve to ipv6 addresses.
 .RE
+.SH CURLOPT_CONNECT_ONLY
+Pass a long. A non-zero parameter tells the library to perform any required
+proxy authentication and connection setup, but no data transfer.
+
+This option is useful with the \fICURLINFO_LASTSOCKET\fP option to
+\fIcurl_easy_getinfo(3)\fP. The library can set up the connection and then the
+application can obtain the most recently used socket for special data
+transfers. (Added in 7.15.2)
 .SH SSL and SECURITY OPTIONS
 .IP CURLOPT_SSLCERT
 Pass a pointer to a zero terminated string as parameter. The string should be
diff --git a/include/curl/curl.h b/include/curl/curl.h
index 95c478a07..1ad282df8 100644
--- a/include/curl/curl.h
+++ b/include/curl/curl.h
@@ -923,6 +923,10 @@ typedef enum {
   */
   CINIT(LOCALPORTRANGE, LONG, 140),
 
+  /* no transfer, set up connection and let application use the socket by
+     extracting it with CURLINFO_LASTSOCKET */
+  CINIT(CONNECT_ONLY, LONG, 141),
+
   CURLOPT_LASTENTRY /* the last unused */
 } CURLoption;
 
@@ -1277,9 +1281,10 @@ typedef enum {
   CURLINFO_NUM_CONNECTS     = CURLINFO_LONG   + 26,
   CURLINFO_SSL_ENGINES      = CURLINFO_SLIST  + 27,
   CURLINFO_COOKIELIST       = CURLINFO_SLIST  + 28,
+  CURLINFO_LASTSOCKET       = CURLINFO_LONG   + 29,
   /* Fill in new entries below here! */
 
-  CURLINFO_LASTONE          = 28
+  CURLINFO_LASTONE          = 29
 } CURLINFO;
 
 /* CURLINFO_RESPONSE_CODE is the new name for the option previously known as
diff --git a/lib/easy.c b/lib/easy.c
index 2de18037f..d86b755fb 100644
--- a/lib/easy.c
+++ b/lib/easy.c
@@ -527,6 +527,8 @@ CURL *curl_easy_duphandle(CURL *incurl)
     memset(outcurl->state.connects, 0,
            sizeof(struct connectdata *)*outcurl->state.numconnects);
 
+    outcurl->state.lastconnect = -1;
+
     outcurl->progress.flags    = data->progress.flags;
     outcurl->progress.callback = data->progress.callback;
 
diff --git a/lib/ftp.c b/lib/ftp.c
index ecb717696..02732f452 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -1689,7 +1689,7 @@ static CURLcode ftp_state_pasv_resp(struct connectdata *conn,
     ftp_pasv_verbose(conn, conninfo, newhost, connectport);
 
 #ifndef CURL_DISABLE_HTTP
-  if(conn->bits.tunnel_proxy) {
+  if(conn->bits.tunnel_proxy && conn->bits.httpproxy) {
     /* FIX: this MUST wait for a proper connect first if 'connected' is
      * FALSE */
 
@@ -2786,7 +2786,7 @@ CURLcode Curl_ftp_connect(struct connectdata *conn,
   ftp->response_time = 3600; /* set default response time-out */
 
 #ifndef CURL_DISABLE_HTTP
-  if (conn->bits.tunnel_proxy) {
+  if (conn->bits.tunnel_proxy && conn->bits.httpproxy) {
     /* BLOCKING */
     /* We want "seamless" FTP operations through HTTP proxy tunnel */
 
diff --git a/lib/getinfo.c b/lib/getinfo.c
index 47828212b..2a4c3aac4 100644
--- a/lib/getinfo.c
+++ b/lib/getinfo.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2005, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2006, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -187,6 +187,14 @@ CURLcode Curl_getinfo(struct SessionHandle *data, CURLINFO info, ...)
   case CURLINFO_COOKIELIST:
     *param_slistp = Curl_cookie_list(data);
     break;
+  case CURLINFO_LASTSOCKET:
+    if((data->state.lastconnect != -1) &&
+       (data->state.connects[data->state.lastconnect] != NULL))
+      *param_longp = data->state.connects[data->state.lastconnect]->
+        sock[FIRSTSOCKET];
+    else
+      *param_longp = -1;
+    break;
   default:
     return CURLE_BAD_FUNCTION_ARGUMENT;
   }
diff --git a/lib/http.c b/lib/http.c
index 39e2940ff..e15054f57 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -1361,7 +1361,7 @@ CURLcode Curl_http_connect(struct connectdata *conn, bool *done)
    * after the connect has occured, can we start talking SSL
    */
 
-  if(conn->bits.tunnel_proxy) {
+  if(conn->bits.tunnel_proxy && conn->bits.httpproxy) {
 
     /* either SSL over proxy, or explicitly asked for */
     result = Curl_proxyCONNECT(conn, FIRSTSOCKET,
diff --git a/lib/multi.c b/lib/multi.c
index a60e1f5a9..a7d1988d6 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2005, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2006, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -522,41 +522,50 @@ CURLMcode curl_multi_perform(CURLM *multi_handle, int *running_handles)
         break;
 
       case CURLM_STATE_DO:
-        /* Perform the protocol's DO action */
-        easy->result = Curl_do(&easy->easy_conn, &dophase_done);
+        if(easy->easy_handle->set.connect_only) {
+          /* keep connection open for application to use the socket */
+          easy->easy_conn->bits.close = FALSE;
+          multistate(easy, CURLM_STATE_DONE);
+          easy->result = CURLE_OK;
+          result = CURLM_OK;
+        }
+        else {
+          /* Perform the protocol's DO action */
+          easy->result = Curl_do(&easy->easy_conn, &dophase_done);
 
-        if(CURLE_OK == easy->result) {
+          if(CURLE_OK == easy->result) {
 
-          if(!dophase_done) {
-            /* DO was not completed in one function call, we must continue
-               DOING... */
-            multistate(easy, CURLM_STATE_DOING);
-            result = CURLM_OK;
-          }
+            if(!dophase_done) {
+              /* DO was not completed in one function call, we must continue
+                 DOING... */
+              multistate(easy, CURLM_STATE_DOING);
+              result = CURLM_OK;
+            }
 
-          /* after DO, go PERFORM... or DO_MORE */
-          else if(easy->easy_conn->bits.do_more) {
-            /* we're supposed to do more, but we need to sit down, relax
-               and wait a little while first */
-            multistate(easy, CURLM_STATE_DO_MORE);
-            result = CURLM_OK;
+            /* after DO, go PERFORM... or DO_MORE */
+            else if(easy->easy_conn->bits.do_more) {
+              /* we're supposed to do more, but we need to sit down, relax
+                 and wait a little while first */
+              multistate(easy, CURLM_STATE_DO_MORE);
+              result = CURLM_OK;
+            }
+            else {
+              /* we're done with the DO, now PERFORM */
+              easy->result = Curl_readwrite_init(easy->easy_conn);
+              if(CURLE_OK == easy->result) {
+                multistate(easy, CURLM_STATE_PERFORM);
+                result = CURLM_CALL_MULTI_PERFORM;
+              }
+            }
           }
           else {
-            /* we're done with the DO, now PERFORM */
-            easy->result = Curl_readwrite_init(easy->easy_conn);
-            if(CURLE_OK == easy->result) {
-              multistate(easy, CURLM_STATE_PERFORM);
-              result = CURLM_CALL_MULTI_PERFORM;
-            }
+            /* failure detected */
+            Curl_posttransfer(easy->easy_handle);
+            Curl_done(&easy->easy_conn, easy->result);
+            Curl_disconnect(easy->easy_conn); /* close the connection */
+            easy->easy_conn = NULL;           /* no more connection */
           }
         }
-        else {
-          /* failure detected */
-          Curl_posttransfer(easy->easy_handle);
-          Curl_done(&easy->easy_conn, easy->result);
-          Curl_disconnect(easy->easy_conn); /* close the connection */
-          easy->easy_conn = NULL;           /* no more connection */
-        }
         break;
 
       case CURLM_STATE_DOING:
diff --git a/lib/transfer.c b/lib/transfer.c
index 50a8bae98..2fbc2c615 100644
--- a/lib/transfer.c
+++ b/lib/transfer.c
@@ -2159,6 +2159,12 @@ CURLcode Curl_perform(struct SessionHandle *data)
 
     if(res == CURLE_OK) {
       bool do_done;
+      if(data->set.connect_only) {
+        /* keep connection open for application to use the socket */
+        conn->bits.close = FALSE;
+        res = Curl_done(&conn, CURLE_OK);
+        break;
+      }
       res = Curl_do(&conn, &do_done);
 
       /* for non 3rd party transfer only */
diff --git a/lib/url.c b/lib/url.c
index f17213f79..49e7c1cbf 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -352,6 +352,9 @@ CURLcode Curl_open(struct SessionHandle **curl)
       memset(data->state.connects, 0,
              sizeof(struct connectdata *)*data->state.numconnects);
 
+    /* most recent connection is not yet defined */
+    data->state.lastconnect = -1;
+
     /*
      * libcurl 7.10 introduced SSL verification *by default*! This needs to be
      * switched off unless wanted.
@@ -432,6 +435,10 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
            are being removed! */
         for(i=newconnects; i< data->state.numconnects; i++)
           Curl_disconnect(data->state.connects[i]);
+
+        /* If the most recent connection is no longer valid, mark it invalid. */
+        if(data->state.lastconnect <= newconnects)
+          data->state.lastconnect = -1;
       }
       if(newconnects) {
         newptr= (struct connectdata **)
@@ -453,8 +460,9 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
         /* zero makes NO cache at all */
         if(data->state.connects)
           free(data->state.connects);
-        data->state.connects=NULL;
-        data->state.numconnects=0;
+        data->state.connects = NULL;
+        data->state.numconnects = 0;
+        data->state.lastconnect = -1;
       }
     }
     break;
@@ -1471,6 +1479,13 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
     data->set.ignorecl = va_arg(param, long)?TRUE:FALSE;
     break;
 
+  case CURLOPT_CONNECT_ONLY:
+    /*
+     * No data transfer, set up connection and let application use the socket
+     */
+    data->set.connect_only = va_arg(param, long)?TRUE:FALSE;
+    break;
+
   default:
     /* unknown tag and its companion, just ignore: */
     result = CURLE_FAILED_INIT; /* correct this */
@@ -3811,10 +3826,14 @@ CURLcode Curl_done(struct connectdata **connp,
     if(!result && res2)
       result = res2;
   }
-  else
+  else {
+    /* remember the most recently used connection */
+    data->state.lastconnect = conn->connectindex;
+
     infof(data, "Connection #%ld to host %s left intact\n",
           conn->connectindex,
           conn->bits.httpproxy?conn->proxy.dispname:conn->host.dispname);
+  }
 
   return result;
 }
diff --git a/lib/urldata.h b/lib/urldata.h
index 96494a7ce..a3802b7c3 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -856,6 +856,7 @@ struct UrlState {
      set, it holds an allocated connection. */
   struct connectdata **connects;
   long numconnects; /* size of the 'connects' array */
+  int lastconnect;  /* index of most recent connect or -1 if undefined */
 
   char *headerbuff; /* allocated buffer to store headers in */
   size_t headersize;   /* size of the allocation */
@@ -1083,6 +1084,7 @@ struct UserDefined {
   bool ignorecl;         /* ignore content length */
   bool ftp_skip_ip;      /* skip the IP address the FTP server passes on to
                             us */
+  bool connect_only;     /* make connection, let application use the socket */
 };
 
 /*