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 creates a role for RFC3549 Netlink monitoring.
If the OS supports it (currently, linux) then each pt creates a wsi
with the netlink role and dumps the current routing table at pt init.
It then maintains a cache of the routing table in each pt.
Upon routing table changes an SMD message is issued as an event, and
Captive Portal Detection is triggered.
All of the pt's current connections are reassessed for routability under
the changed routing table, those that no longer have a valid route or
gateway are closed.
Add a member to the vh init struct allowing control of the overall
connection wait introduced in an earlier patch. Set it to 20s
by default.
The timeout_secs member controls the individual DNS result
connect timeout and is reduced to 5s by default.
Adds client support for MQTT QoS0 and QoS1, compatible with AWS IoT
Supports stream binding where independent client connections to the
same endpoint can mux on a single tcp + tls connection with topic
routing managed internally.
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.
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
