Callbacks can ask the caller to, eg, destroy the ss handle now. But some
callback returns are handled and produced inside other helper apis, eg
lws_ss_backoff() may have to had fulfilled the callback request to destroy
the ss... therefore it has to signal to its caller, and its callers have
to check and exit their flow accordingly.
This differentiates between client connections for retry / writeable requests
and explicit lws_ss_client_connect() api calls. The former effectively uses
retry / backoff, and the latter resets the retry / backoff.
If you receive ALL_RETRIES_FAILED due to the retry policy, you can do whatever
you need to do there and call lws_ss_client_connect() to try to connect again
with a fresh, reset retry / backoff state.
- Add low level system message distibution framework
- Add support for local Secure Streams to participate using _lws_smd streamtype
- Add apit test and minimal example
- Add SS proxy support for _lws_smd
See minimal-secure-streams-smd README.md
Sometimes we need to find out the substituted length before we can
allocate and actually store it. Teach strexp that if we set the
output buffer to NULL (and the output length to something big) we
are asking for the substituted length and to not produce output.
It's not safe to destroy objects inside a callback from a parent that
still has references to the object.
Formalize what the user code can indicate by its return code from the
callback functions and provide the implementations at the parents.
- LWSSSSRET_OK: no action, OK
- LWSSSSRET_DISCONNECT_ME: disconnect the underlying connection
- LWSSSSRET_DESTROY_ME: destroy the ss object
- LWSSSSRET_TX_DONT_SEND: for tx, give up the tx opportunity since nothing to send
Some streamtypes do not pass or receive payload meaningfully. Allow them
to just leave their related cb NULL. Ditto for state, although I'm not sure
how useful such a streamtype can be.
Adapt the pt sul owner list to be an array, and define two different lists,
one that acts like before and is the default for existing users, and another
that has the ability to cooperate with systemwide suspend to restrict the
interval spent suspended so that it will wake in time for the earliest
thing on this wake-suspend sul list.
Clean the api a bit and add lws_sul_cancel() that only needs the sul as the
argument.
Add a flag for client creation info to indicate that this client connection
is important enough that, eg, validity checking it to detect silently dead
connections should go on the wake-suspend sul list. That flag is exposed in
secure streams policy so it can be added to a streamtype with
"swake_validity": true
Deprecate out the old vhost timer stuff that predates sul. Add a flag
LWS_WITH_DEPRECATED_THINGS in cmake so users can get it back temporarily
before it will be removed in a v4.2.
Adapt all remaining in-tree users of it to use explicit suls.
There are a few automatic things that look for streamtypes that may or
may not exist now
- captive_portal_detect
- fetch_policy
- api_amazon_com_auth
logging them as notice every startup is pretty intrusive, change to info.
For general OpenSSL case, we leave connection validity to system trust
store bundle to decide; even for mbedtls it may have been passed a
bundle externally and we don't want to have to list the x.509 stack
explicitly for a server we don't have any control over.
Instead of erroring out, allow the case no trust store is specified,
just use vhost[0] and let the system trust store decide if it likes
the server's cert or not.
No ABI change.
The endpoint field in streamtype policy may continue to just be the
hostname, like "warmcat.com".
But it's also possible now to be a url-formatted string, like, eg,
"https://warmcat.com:444/mailman/listinfo"
If so (ie, if it contains a : ) then the decoded elements may override
if tls is enabled, the endpoint address, the port, and the url path.
No ABI change.
Implement Captive Portal detection support in lws, with the actual
detection happening in platform code hooked up by lws_system_ops_t.
Add an implementation using Secure Streams as well, if the policy
defines captive_portal_detect streamtype, a SS using that streamtype
is used to probe if it's behind a captive portal.
Secure Streams is an optional layer on top of lws that separates policy
like endpoint selection and tls cert validation into a device JSON
policy document.
Code that wants to open a client connection just specifies a streamtype name,
and no longer deals with details like the endpoint, the protocol (!) or anything
else other than payloads and optionally generic metadata; the JSON policy
contains all the details for each streamtype. h1, h2, ws and mqtt client
connections are supported.
Logical secure streams outlive any particular connection and supports "nailed-up"
connectivity regardless of underlying connection stability.
