When configured with '--without-ssl --with-nss', NTLM authentication
now uses NSS crypto library for MD5 and DES. For MD4 we have a local
implementation in that case. More details are available at
https://bugzilla.redhat.com/603783
In order to get it working, curl_global_init() must be called with
CURL_GLOBAL_SSL or CURL_GLOBAL_ALL. That's necessary because NSS needs
to be initialized globally and we do so only when the NSS library is
actually required by protocol. The mentioned call of curl_global_init()
is responsible for creating of the initialization mutex.
There was also slightly changed the NSS initialization scenario, in
particular, loading of the NSS PEM module. It used to be loaded always
right after the NSS library was initialized. Now the library is
initialized as soon as any SSL or NTLM is required, while the PEM module
is prevented from being loaded until the SSL is actually required.
HTTP Pipelining with libcurl
============================
Background
Since pipelining implies that one or more requests are sent to a server before
the previous response(s) have been received, we only support it for multi
interface use.
Considerations
When using the multi interface, you create one easy handle for each transfer.
Bascially any number of handles can be created, added and used with the multi
interface - simultaneously. It is an interface designed to allow many
simultaneous transfers while still using a single thread. Pipelining does not
change any of these details.
API
We've added a new option to curl_multi_setopt() called CURLMOPT_PIPELINING
that enables "attempted pipelining" and then all easy handles used on that
handle will attempt to use an existing pipeline.
Details
- A pipeline is only created if a previous connection exists to the same IP
address that the new request is being made to use.
- Pipelines are only supported for HTTP(S) as no other currently supported
protocol has features resemembling this, but we still name this feature
plain 'pipelining' to possibly one day support it for other protocols as
well.
- HTTP Pipelining is for GET and HEAD requests only.
- When a pipeline is in use, we must take precautions so that when used easy
handles (i.e those who still wait for a response) are removed from the multi
handle, we must deal with the outstanding response nicely.
- Explicitly asking for pipelining handle X and handle Y won't be supported.
It isn't easy for an app to do this association. The lib should probably
still resolve the second one properly to make sure that they actually _can_
be considered for pipelining. Also, asking for explicit pipelining on handle
X may be tricky when handle X get a closed connection.
- We need options to control max pipeline length, and probably how to behave
if we reach that limit. As was discussed on the list, it can probably be
made very complicated, so perhaps we can think of a way to pass all
variables involved to a callback and let the application decide how to act
in specific situations. Either way, these fancy options are only interesting
to work on when everything is working and we have working apps to test with.
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