There are a few build options that are trying to keep and report
various statistics
- DETAILED_LATENCY
- SERVER_STATUS
- WITH_STATS
remove all those and establish a generic rplacement, lws_metrics.
lws_metrics makes its stats available via an lws_system ops function
pointer that the user code can set.
Openmetrics export is supported, for, eg, prometheus scraping.
The various stream transitions for direct ss, SSPC, smd, and
different protocols are all handled in different code, let's
stop hoping for the best and add a state transition validation
function that is used everywhere we pass a state change to a
user callback, and knows what is valid for the user state()
callback to see next, given the last state it was shown.
Let's assert if lws manages to violate that so we can find
where the problem is and provide a stricter guarantee about
what user state handler will see, no matter if ss or sspc
or other cases.
To facilitate that, move the states to start from 1, where
0 indicates the state unset.
This is a huge patch that should be a global NOP.
For unix type platforms it enables -Wconversion to issue warnings (-> error)
for all automatic casts that seem less than ideal but are normally concealed
by the toolchain.
This is things like passing an int to a size_t argument. Once enabled, I
went through all args on my default build (which build most things) and
tried to make the removed default cast explicit.
With that approach it neither change nor bloat the code, since it compiles
to whatever it was doing before, just with the casts made explicit... in a
few cases I changed some length args from int to size_t but largely left
the causes alone.
From now on, new code that is relying on less than ideal casting
will complain and nudge me to improve it by warnings.
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)
RFC6724 defines an ipv6-centric DNS result sorting algorithm, that
takes route and source address route information for the results
given by the DNS resolution, and sorts them in order of preferability,
which defines the order they should be tried in.
If LWS_WITH_NETLINK, then lws takes care about collecting and monitoring
the interface, route and source address information, and uses it to
perform the RFC6724 sorting to re-sort the DNS before trying to make
the connections.
This adds a helper to test if an sa46 is on an sa46-based subnet.
The compare helper is adapted to say that non INET/INET6 addresses with
the same AF match.
If we connect out to an IP address, or we adopt a connected socket,
from now on we want to hold the peer sockaddr in the wsi.
Adapt ACCESS_LOG to use this new copy rather than keep the
stringified version.
With SMP + event lib, extra locking is required when dealing with cross-thread
adoption case, and cross-vhost cases like wsi close, we need to hold the pt or
context lock.
These lock apis are NOPs when LWS_MAX_SMP == 1 which is the default.
For server, if the adoption of the incoming connection proceeds but then
fails early on, eg, tls alert due to hostname mismatch with cert, the
wsi close happens but it doesn't clean up the invalidated reference to
itself in the server ss object... if it became established, that's handled
by the ss protocol callback.
This patch helps the close path to understand there is a related ss object
and to clean up after itself.
Event lib support as it has been isn't scaling well, at the low level
libevent and libev headers have a namespace conflict so they can't
both be built into the same image, and at the distro level, binding
all the event libs to libwebsockets.so makes a bloaty situation for
packaging, lws will drag in all the event libs every time.
This patch implements the plan discussed here
https://github.com/warmcat/libwebsockets/issues/1980
and refactors the event lib support so they are built into isolated
plugins and bound at runtime according to what the application says
it wants to use. The event lib plugins can be packaged individually
so that only the needed sets of support are installed (perhaps none
of them if the user code is OK with the default poll() loop). And
dependent user code can mark the specific event loop plugin package
as required so pieces are added as needed.
The eventlib-foreign example is also refactored to build the selected
lib support isolated.
A readme is added detailing the changes and how to use them.
https://libwebsockets.org/git/libwebsockets/tree/READMEs/README.event-libs.md
Add initial support for defining servers using Secure Streams
policy and api semantics.
Serving h1, h2 and ws should be functional, the new minimal
example shows a combined http + SS server with an incrementing
ws message shown in the browser over tls, in around 200 lines
of user code.
NOP out anything to do with plugins, they're not currently used.
Update the docs correspondingly.
Currently we always reserve a fakewsi per pt so events that don't have a related actual
wsi, like vhost-protocol-init or vhost cert init via protocol callback can make callbacks
that look reasonable to user protocol handler code expecting a valid wsi every time.
This patch splits out stuff that user callbacks often unconditionally expect to be in
a wsi, like context pointer, vhost pointer etc into a substructure, which is composed
into struct lws at the top of it. Internal references (struct lws is opaque, so there
are only internal references) are all updated to go via the substructre, the compiler
should make that a NOP.
Helpers are added when fakewsi is used and referenced.
If not PLAT_FREERTOS, we continue to provide a full fakewsi in the pt as before,
although the helpers improve consistency by zeroing down the substructure. There is
a huge amount of user code out there over the last 10 years that did not always have
the minimal examples to follow, some of it does some unexpected things.
If it is PLAT_FREERTOS, that is a newer thing in lws and users have the benefit of
being able to follow the minimal examples' approach. For PLAT_FREERTOS we don't
reserve the fakewsi in the pt any more, saving around 800 bytes. The helpers then
create a struct lws_a (the substructure) on the stack, zero it down (but it is only
like 4 pointers) and prepare it with whatever we know like the context.
Then we cast it to a struct lws * and use it in the user protocol handler call.
In this case, the remainder of the struct lws is undefined. However the amount of
old protocol handlers that might touch things outside of the substructure in
PLAT_FREERTOS is very limited compared to legacy lws user code and the saving is
significant on constrained devices.
User handlers should not be touching everything in a wsi every time anyway, there
are several cases where there is no valid wsi to do the call with. Dereference of
things outside the substructure should only happen when the callback reason shows
there is a valid wsi bound to the activity (as in all the minimal examples).
There are some minor public api type improvements rather than cast everywhere
inside lws and user code to work around them... these changed from int to
size_t
- lws_buflist_use_segment() return
- lws_tokenize_t .len and .token_len
- lws_tokenize_cstr() length
- lws_get_peer_simple() namelen
- lws_get_peer_simple_fd() namelen, int fd -> lws_sockfd_type fd
- lws_write_numeric_address() len
- lws_sa46_write_numeric_address() len
These changes are typically a NOP for user code
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.
This adds the option to have lws do its own dns resolution on
the event loop, without blocking. Existing implementations get
the name resolution done by the libc, which is blocking. In
the case you are opening client connections but need to carefully
manage latency, another connection opening and doing the name
resolution becomes a big problem.
Currently it supports
- ipv4 / A records
- ipv6 / AAAA records
- ipv4-over-ipv6 ::ffff:1.2.3.4 A record promotion for ipv6
- only one server supported over UDP :53
- nameserver discovery on linux, windows, freertos
It also has some nice advantages
- lws-style paranoid response parsing
- random unique tid generation to increase difficulty of poisoning
- it's really integrated with the lws event loop, it does not spawn
threads or use the libc resolver, and of course no blocking at all
- platform-specific server address capturing (from /etc/resolv.conf
on linux, windows apis on windows)
- it has LRU caching
- piggybacking (multiple requests before the first completes go on
a list on the first request, not spawn multiple requests)
- observes TTL in cache
- TTL and timeout use lws_sul timers on the event loop
- ipv6 pieces only built if cmake LWS_IPV6 enabled
