FTP: when EPSV gets a 229 but fails to connect, retry with PASV

This is a regression as this logic used to work. It isn't clear when it
broke, but I'm assuming in 7.28.0 when we went all-multi internally.

This likely never worked with the multi interface. As the failed
connection is detected once the multi state has reached DO_MORE, the
Curl_do_more() function was now expanded somewhat so that the
ftp_do_more() function can request to go "back" to the previous state
when it makes another attempt - using PASV.

Added test case 1233 to verify this fix. It has the little issue that it
assumes no service is listening/accepting connections on port 1...

Reported-by: byte_bucket in the #curl IRC channel

1 files changed, 6 insertions, 4 deletions

diff --git a/lib/url.c b/lib/url.c
index d2149abd8..7cec5bccd 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -5841,18 +5841,20 @@ CURLcode Curl_do(struct connectdata **connp, bool *done)
  *
  * TODO: A future libcurl should be able to work away this state.
  *
+ * 'complete' can return 0 for incomplete, 1 for done and -1 for go back to
+ * DOING state there's more work to do!
  */
 
-CURLcode Curl_do_more(struct connectdata *conn, bool *completed)
+CURLcode Curl_do_more(struct connectdata *conn, int *complete)
 {
   CURLcode result=CURLE_OK;
 
-  *completed = FALSE;
+  *complete = 0;
 
   if(conn->handler->do_more)
-    result = conn->handler->do_more(conn, completed);
+    result = conn->handler->do_more(conn, complete);
 
-  if(!result && *completed)
+  if(!result && (*complete == 1))
     /* do_complete must be called after the protocol-specific DO function */
     do_complete(conn);