Add lwsac helper api to allow user code to perform constant string folding
easily within an lwsac. After isolating a string or blob that it wants to store in
the lwsac and point to, it can check if the string or blob already exists earlier
in the lwsac first, and if so just point to that without copying it in again.
For some formats with repeated strings like JSON, the saving can add up to
something useful.
The sul callback is allowed to do anything to the sul list, it's
not possible to safely iterate it inbetween calls.
Luckily because it's sorted, we only ever care about the current
head, so switch to iterating it like that.
Handle the situation that we are told to use a CNAME, but the CNAME is not resolved
by the remote server... adapt the query to resolve the CNAME and restart it, while
retaining the original query name for the cache entry generation.
"Recursion" doesn't mean function-calling-a-function type recursion, it remains
completely asynchronous on the event loop.
We overallocate at the start by LWS_PRE so we can use
buflist content directly with lws_write, this has us also
overallocate by 1 at the end. There's a corner case with
cgi where it's receiving bulk POST data to pass on to cgi
stdin and wants to make sure there's a NUL just past the
end... this makes sure we have space for it.
Generic lws_system IPv4 DHCP client
- netif and route control via lib/plat apis
- linux plat pieces implemented
- Uses raw ip socket for UDP broadcast and rx
- security-aware
- usual stuff plus up to 4 x dns server
If it's enabled for build, it holds the system
state at DHCP until at least one registered interface
has acquired a set of IP / mask / router / DNS server
It uses PF_PACKET which is Linux-only atm. But those
areas are isolated into plat code.
TODOs
- lease timing and reacquire
- plat pieces for other than Linux
lws has been able to generate client multipart mime as shown
in minimal-http-client-post, but it requires a lot of user
boilerplate to handle the boundary, related transaction header,
and multipart headers.
This patch adds a client creation flag to indicate it will
carry multipart mime, which autocreates the boundary string
and applies the transaction header with it, and an api to
form the boundary headers between the different mime parts
and the terminating boundary.
This affects max header size since we use the latter half
of the pt_serv_buf to prepare the (possibly huge) auth token.
Adapt the pt_serv_buf_size in the hugeurl example.
Some servers set the tx credit to the absolute max and then add to it... this is illegal
(and checked for in h2spec). Add a quirk flag that works around it by reducing the
initial tx credit size by a factor of 16.
This shouldn't be necessary; just END_HEADERS flag should be enough.
But nghttp2 will not talk to us unless we end the stream from our side.
Unfortunately ending the stream at the time we sent the headers means
we cannot support the long poll half-close scheme. So add a quirk
flag to optionally support this behaviour of nghttp2 when the client
is creating the connection.
h1 and h2 has a bunch of code supporting autobinding outgoing client connections
to be streams in, or queued as pipelined on, the same / existing single network
connection, if it's to the same endpoint.
Adapt this http-specific code and active connection tracking to be usable for
generic muxable protocols the same way.
lws_now_usecs() uses monotonic time now. It's not sync'd with
wallclock time and the two can't be mixed. Switch to
gettimeofday which is nonmonotonic and use also for fractional
time to avoid fractional secs in logs being unrelated to integer
seconds boundary.
Rather than do all switches by hand on the minimal examples,
add a helper that knows some "builtin" ones like -d and
others to set context options you might want to use in
any example.
Introduce a generic lws_state object with notification handlers
that may be registered in a chain.
Implement one of those in the context to manage the "system state".
Allow other pieces of lws and user code to register notification
handlers on a context list. Handlers can object to or take over
responsibility to move forward and retry system state changes if
they know that some dependent action must succeed first.
For example if the system time is invalid, we cannot move on to
a state where anything can do tls until that has been corrected.
Refactor everything around ping / pong handling in ws and h2, so there
is instead a protocol-independent validity lws_sul tracking how long it
has been since the last exchange that confirms the operation of the
network connection in both directions.
Clean out periodic role callback and replace the last two role users
with discrete lws_sul for each pt.
It was already correct but add helpers to isolate and deduplicate
processing adding and closing a generically immortal stream.
Change the default 31s h2 network connection timeout to be settable
by .keepalive_timeout if nonzero.
Add a public api allowing a client h2 stream to transition to
half-closed LOCAL (by sending a 0-byte DATA with END_STREAM) and
mark itself as immortal to create a read-only long-poll stream
if the server allows it.
Add a vhost server option flag LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL
which allows the vhost to treat half-closed remotes as immortal long
poll streams.
There's no longer any reason to come out of sleep for periodic service
which has been eliminated by lws_sul.
With event libs, there is no opportunity to do it anyway since their
event loop is atomic and makes callbacks and sleeps until it is stopped.
But some users are relying on the old poll() service loop as
glue that's difficult to replace. So for now help that happen by
accepting the timeout_ms of -1 as meaning sample poll and service
what's there without any wait.
With http, the protocol doesn't indicate where the headers end and the
next transaction or body begin. Until now, we handled that for client
header response parsing by reading from the tls buffer bytewise.
This modernizes the code to read in up to 256-byte chunks and parse
the chunks in one hit (the parse API is already set up for doing this
elsewhere).
Now we have a generic input buflist, adapt the parser loop to go through
that and arrange that any leftovers are placed on there.
