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
Add helpers to parse and print ipv4 and ipv6 numeric addresses
in all the canonical formats.
Expose internal lws_sockaddr46 union and add helper wrappers
to directly operate on sa46.
Improve the code around stash, getting rid of the strdups for a net
code reduction. Remove the special destroy helper for stash since
it becomes a one-liner.
Trade several stack allocs in the client reset function for a single
sized brief heap alloc to reduce peak stack alloc by around 700 bytes.
External poll support generates a lot of messages on a busy system
for no value unless you're one of the few people using it. It's
not recommended for new users and is there for backwards compatibility.
Make it not built by default and selectable by cmake option.
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
There are quite a few linked-lists of things that want events after
some period. This introduces a type binding an lws_dll2 for the
list and a lws_usec_t for the duration.
The wsi timeouts, the hrtimer and the sequencer timeouts are converted
to use these, also in the common event wait calculation.
lws_dll2 removes the downsides of lws_dll and adds new features like a
running member count and explicit owner type... it's cleaner and more
robust (eg, nodes know their owner, so they can casually switch between
list owners and remove themselves without the code knowing the owner).
This deprecates lws_dll, but since it's public it allows it to continue
to be built for 4.0 release if you give cmake LWS_WITH_DEPRECATED_LWS_DLL.
All remaining internal users of lws_dll are migrated to lws_dll2.
Adapt service loops and event libs to use microsecond waits
internally, for hrtimer and sequencer. Reduce granularity
according to platform / event lib wait.
Add a helper so there's a single place to extend it.
Since the messages are queued and then read in order from the event loop
thread, it's not generally safe to pass pointers to argument structs,
since there's no guarantee the lifetime of the thing sending the message
lasted until the sequencer read the message.
This puts pressure on the single void * argument-passed-as-value... this patch
adds a second void * argument-passed-as-value so it's more possible to put
what's needed directly in the argument.
It's also possible to alloc the argument on the heap and have the sequencer
callback free it after it has read it.
Add a generic table-based backoff scheme and a helper to track the
try count and calculate the next delay in ms.
Allow lws_sequencer_t to be given one of these at creation time...
since the number of creation args is getting a bit too much
convert that to an info struct at the same time.
The logic in the loops for insertion and deletion from the
mini, forced to non ulimit max fds in the pt mode was not
quite right.
It showed up in hard to reproduce problem with the ws client
spam test that uses the mini mode, on travis. This should
fix the root cause.
