This changes the approach of tx credit management to set the
initial stream tx credit window to zero. This is the only way
with RFC7540 to gain the ability to selectively precisely rx
flow control incoming streams.
At the time the headers are sent, a WINDOW_UPDATE is sent with
the initial tx credit towards us for that specific stream. By
default, this acts as before with a 256KB window added for both
the stream and the nwsi, and additional window management sent
as stuff is received.
It's now also possible to set a member in the client info
struct and a new option LCCSCF_H2_MANUAL_RXFLOW to precisely
manage both the initial tx credit for a specific stream and
the ongoing rate limit by meting out further tx credit
manually.
Add another minimal example http-client-h2-rxflow demonstrating how
to force a connection's peer's initial budget to transmit to us
and control it during the connection lifetime to restrict the amount
of incoming data we have to buffer.
The %.*s is very handy to print strings where you have a length, but
there is no NUL termination. It's quite widely supported but at least
one vendor RTOS toolchain doesn't have it.
Since there aren't that many uses of it yet, audit all uses and
convert to a new helper lws_strnncpy() which uses the smaller of
two lengths.
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.
Old certs were getting near the end of their life and we switched the
server to use letsencrypt. The root and intermediate needed for the
mbedtls case changed accordingly
wsi timeout, wsi hrtimer, sequencer timeout and vh-protocol timer
all now participate on a single sorted us list.
The whole idea of polling wakes is thrown out, poll waits ignore the
timeout field and always use infinite timeouts.
Introduce a public api that can schedule its own callback from the event
loop with us resolution (usually ms is all the platform can do).
Upgrade timeouts and sequencer timeouts to also be able to use us resolution.
Introduce a prepared fakewsi in the pt, so we don't have to allocate
one on the heap when we need it.
Directly handle vh-protocol timer if LWS_MAX_SMP == 1
An lws context usually contains a processwide fd -> wsi lookup table.
This allows any possible fd returned by a *nix type OS to be immediately
converted to a wsi just by indexing an array of struct lws * the size of
the highest possible fd, as found by ulimit -n or similar.
This works modestly for Linux type systems where the default ulimit -n for
a process is 1024, it means a 4KB or 8KB lookup table for 32-bit or
64-bit systems.
However in the case your lws usage is much simpler, like one outgoing
client connection and no serving, this represents increasing waste. It's
made much worse if the system has a much larger default ulimit -n, eg 1M,
the table is occupying 4MB or 8MB, of which you will only use one.
Even so, because lws can't be sure the OS won't return a socket fd at any
number up to (ulimit -n - 1), it has to allocate the whole lookup table
at the moment.
This patch looks to see if the context creation info is setting
info->fd_limit_per_thread... if it leaves it at the default 0, then
everything is as it was before this patch. However if finds that
(info->fd_limit_per_thread * actual_number_of_service_threads) where
the default number of service threads is 1, is less than the fd limit
set by ulimit -n, lws switches to a slower lookup table scheme, which
only allocates the requested number of slots. Lookups happen then by
iterating the table and comparing rather than indexing the array
directly, which is obviously somewhat of a performance hit.
However in the case where you know lws will only have a very few wsi
maximum, this method can very usefully trade off speed to be able to
avoid the allocation sized by ulimit -n.
minimal examples for client that can make use of this are also modified
by this patch to use the smaller context allocations.
https://libwebsockets.org/pipermail/libwebsockets/2019-April/007937.html
thanks to Bruce Perens for noting it.
This doesn't change the intention or status of the CC0 files, they were
pure CC0 before (ie, public domain) and they are pure CC0 now. It just
gets rid of the (C) part at the top of the dedication which may be read
to be a bit contradictory since the purpose is to make it public domain.
This converts several of the selftests to return a status in their exit code
about whether they 'worked'.
A small bash script framework is added, with a selftest.sh in the mininmal
example dirs that support it, and a ./minimal-examples/selftests.sh script
that can be run from the build dir with no args that discovers and runs all
the selftest.sh scripts underneath.
That is also integrated into travis and the enabled tests must pass now for
travis to pass. Travis does not have a modern libuv so it can't run a
couple of tests which are nulled out if it sees it's running in travis env.
This adds h2 http support for the client api.
The public client api requires no changes, it will detect by
ALPN if the server can handle http/2, if so, it will use it.
Multiple client connections using the lws api will be mapped on
to the same single http/2 + tls socket using http/2 streams
that are serviced simultaneously where possible.
AG: unlike openssl, mbedtls does not load the system trust store.
So this change will make client tls operations that work OK on openssl fail on
mbedtls unless you provide the correct CA cert.
This allows lws to distinguish between untrusted CAs, hostname
mismatches, expired certificates.
NOTE: LCCSCF_ALLOW_SELFSIGNED actually allows for untrusted CAs, and
will also skip hostname verification. This is somewhat a limitiation of
the current lws verification process.
AG: improve error reporting up to the CLIENT_CONNECTION_ERROR argument
and add a note specific to mbedtls in the test client. Adapt the test
client to note the CA requirement if built with mbedTLS. Adapt the
minimal test clients to have the CAs available and use them if mbedTLS.
This adds an lws cmake option that builds all the minimal examples as part of lws,
it's useful for QA.
It adds a macro to examples that depend on a particular lws configuration to understand
they should just null out their project definition in builds where the lws configuration
requirement is not met, and we are building as part of lws.
It also adapts all the example library additions to select the just-built-but-not-yet-installed
library in the case it is built as part of lws. If built standalone, it now uses the cmake
platform-abstracted way to add the library requirement too.
