New connection filter `cf-dns` that manages DNS queries. If hands
out addresses and HTTPS-RR records to anyone interested. Used by
HTTPS and IP happy eyeballing.
Information may become available *before* the libcurl "dns entry"
is complete, e.g. all queries have been answered. The cf-ip-happy
filter uses this information to start connection attempts as soon
as the first address is available.
The multi MSTATE_RESOLVING was removed. A new connection always
goes to MSTATE_CONNECTING. The connectdata bit `dns_resolved`
indicates when DNS information is complete. This is used for
error reporting and starting the progress meter.
Removed dns entries `data->state.dns[i]`, as the `cf-dns` filter
now keeps the reference now.
Many minor tweaks for making this work and pass address information
around safely.
Closes#21027
Delete where unused, include where to used to avoid relying on
side-effect of other headers.
Also: delete "for curlx_nonblock" comments. That's the only symbol
offered by this header.
Closes#20055
Make `port` member in these struct of type `uint16_t`.
add `uint8_t transport` to `struct ip_quadruple
Define TRNSPRT_NONE as 0. By assigning a valid transport only on a
successful connection, it is clear when the ip_quadruple members are
valid. Also, for transports not involving ports, the getinfos for
`CURLINFO_PRIMARY_PORT` and `CURLINFO_LOCAL_PORT` will now always return
-1.
Make all `transport` members and parameters of type `uint8_t`.
Document the return value of `CURLINFO_LOCAL_PORT` and
`CURLINFO_PRIMARY_PORT` in this regard. Add tests that writeout stats
report ports correctly.
Closes#19708
When `CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS` expires, start the next ip
connect attempt, but keep all ongoing attempts alive.
Separate happy-eyeballs connection filter into own source files.
Closes#18105
