On an error path, we might not have a valid spa / lejp to destroy.
In that case, don't hurl ourselves into calling a
function pointer that can be NULL for the destroy cb.
This adds some new objects and helpers for keeping and logging
info on grouped allocations, a group is, eg, SS handles or client
wsis.
Allocated objects get a context-unique "tag" string intended to replace
%p / wsi pointers etc. Pointers quickly become confusing when
allocations are freed and reused, the tag string won't repeat
until you produce 2^64 objects in a context.
In addition the tag string documents the object group, with prefixes
like "wsi-" or "vh-" and contain object-specific additional
information like the vhost name, address / port or the role of the wsi.
At creation time the lws code can use a format string and args
to add whatever group-specific info makes sense, eg, a wsi bound
to a secure stream can also append the guid of the secure stream,
it's copied into the new object tag and so is still available
cleanly after the stream is destroyed if the wsi outlives it.
A few different places want to create wsis and basically repeat their
own versions of the flow. Let's unify it into one helper in wsi.c
Also require the context lock held (this only impacts LWS_MAX_SMP > 1)
For LWSSSCS_UNREACHABLE state, the additional ord arg has b0 set if the
reason for the unreachability is because the DNS server itself was not
reachable (implying either DNS server is wrongly set, or is not reachable
due to not having connectivity through to it)
If getaddrinfo() is not able to reach the server, there may be
a connectivity problem downstream of the device that has not
been recognized by the Captive Portal Detect pieces yet.
If it looks like that might have happened, used the getaddrinfo()
return to provoke a new CPD scan.
Since client_connect and request_tx can be called from code that expects
the ss handle to be in scope, these calls can't deal with destroying the
ss handle and must pass the lws_ss_state_return_t disposition back to
the caller to handle.
http content-length is not mandatory on POST, making a whole
bunch of difficulties. On h2, the client will set the stream
half-closed by DATA with END_STREAM flag when it is done.
Improve the post data tracking to understand that situation
properly.
With synthetic tests, we can have an h1 connection open to a server
and ask for an h2-specific connection to the same thing... lws will
bind it to the idle h1 connection since the endpoint and tls matches.
This also makes it check that the alpn filtering matches h1 before
allowing that.
