Bug: http://curl.haxx.se/mail/lib-2011-01/0079.html
Reported by: Quinn Slack

As the function doesn't really use the connectdata struct but only the
SessionHanadle struct I modified what argument it wants.

Winsock builds clobber some errno.h defines in setup_once.

On Windows, translate WSAGetLastError() to errno values as GNU
TLS does it internally, too. This is necessary because send() and
recv() on Windows don't set errno when they fail but GNU TLS
expects a proper errno value.

Bug: http://curl.haxx.se/bug/view.cgi?id=3110991

When no timeout is set, we call the socket_ready function with a timeout
value of 0 during handshake, which makes it loop too much/fast in this
function. It also made this function return CURLE_OPERATION_TIMEDOUT
wrongly on a slow handshake.

However, the particular bug report that highlighted this problem is not
solved by this fix, as this fix only makes the more proper error get
reported instead.

Bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=594150
Reported by: Johannes Ernst

FTP(S) use two connections that can be set to different recv and
send functions independently, so by introducing recv+send pairs
in the same manner we already have sockets/connections we can
work with FTPS fine.

This commit fixes the FTPS regression introduced in change d64bd82b.

Howard Chu brought the bulk work of this patch that properly
moves out the sending and recving of data to the parts of the
code that are properly responsible for the various ways of doing
so.

Daniel Stenberg assisted with polishing a few bits and fixed some
minor flaws in the original patch.

Another upside of this patch is that we now abuse CURLcodes less
with the "magic" -1 return codes and instead use CURLE_AGAIN more
consistently.

When multi interface is used, the SSL handshake is no longer
blocking when GnuTLS is used.

The recent overhaul of the SSL recv function made this treat a
zero returned from gnutls_record_recv() as an error, and this
caused our HTTPS test cases to fail. We leave it to upper layer
code to detect if an EOF is a problem or not.

  should introduce an option to disable SNI, but as we're in feature freeze
  now I've addressed the obvious bug here (pointed out by Peter Sylvester): we
  shouldn't try to enable SNI when SSLv2 or SSLv3 is explicitly selected.
  Code for OpenSSL and GnuTLS was fixed. NSS doesn't seem to have a particular
  option for SNI, or are we simply not using it?

  (https://bugzilla.novell.com/523919). When looking at the code, I found
  that also the ptr pointer can leak.

one and store the current one, as it makes the code less complex and I'm not
even sure I can check for the same session id using memcmp() like that.

  corresponding fix in the GnuTLS code: make sure to store the new session id
  in case the re-used one is rejected.

  in the gnutls code where we were checking for negative values for errors,
  when the man pages state that GNUTLS_E_SUCCESS is returned on success and
  other values indicate error conditions.

  curl_global_init() function to properly maintain the performing functions
  thread-safe. We've previously (28 April 2007) moved the init to a later time
  just to avoid it to fail very early when libgcrypt dislikes the situation,
  but that move was bad and the fix should rather be in libgcrypt or
  elsewhere.

  (http://curl.haxx.se/bug/view.cgi?id=2255627) which pointed out that a
  program using libcurl's multi interface to download a HTTPS page with a
  libcurl built powered by OpenSSL, would easily get silly and instead hand
  over SSL details as data instead of the actual HTTP headers and body. This
  happened because libcurl would consider the connection handshake done too
  early. This problem was introduced at September 22nd 2008 with my fix of the
  bug #2107377

  The correct fix is now instead done within the GnuTLS-handling code, as both
  the OpenSSL and the NSS code already deal with this situation in similar
  fashion. I added test case 560 in an attempt to verify this fix, but
  unfortunately it didn't trigger it even before this fix!

used in strequal.c so now all test cases run fine for me again.

  (http://curl.haxx.se/bug/view.cgi?id=2154627) which pointed out that libcurl
  uses strcasecmp() in multiple places where it causes failures when the
  Turkish locale is used. This is because 'i' and 'I' isn't the same letter so
  strcasecmp() on those letters are different in Turkish than in English (or
  just about all other languages). I thus introduced a totally new internal
  function in libcurl (called Curl_ascii_equal) for doing case insentive
  comparisons for english-(ascii?) style strings that thus will make "file"
  and "FILE" match even if the Turkish locale is selected.

void *

  OpenSSL, NSS and GnuTLS-built libcurls.

  OpenSSL, NSS and GnuTLS-built libcurls.

Patch submitted by Kaspar Brand.

  forces it to prefer SSLv3.

  better control at the exact state of the connection's SSL status so that we
  know exactly when it has completed the SSL negotiation or not so that there
  won't be accidental re-uses of connections that are wrongly believed to be
  in SSL-completed-negotiate state.

  such as the CURLOPT_SSL_CTX_FUNCTION one treat that as if it was a Location:
  following. The patch that introduced this feature was done for 7.11.0, but
  this code and functionality has been broken since about 7.15.4 (March 2006)
  with the introduction of non-blocking OpenSSL "connects".

  It was a hack to begin with and since it doesn't work and hasn't worked
  correctly for a long time and nobody has even noticed, I consider it a very
  suitable subject for plain removal. And so it was done.

  verification is requested. Previously it would even return failure if gnutls
  failed to get the server cert even though no verification was asked for.

- Fix my Curl_timeleft() leftover mistake in the gnutls code

  (http://curl.haxx.se/bug/view.cgi?id=1889856): When using the gnutls ssl
  layer, cleaning-up and reinitializing curl ends up with https requests
  failing with "ASN1 parser: Element was not found" errors. Obviously a
  regression added in 7.16.3.

  them all use the same (hopefully correct) logic to make it less error-prone
  and easier to introduce library-wide where it should be used.