Use separate dns cache entries for addresses (A+AAAA) and HTTPS-RR
results. That makes also "negative" results independent of each other.
Dns cache entries, once in use, can no longer be modified safely, as
concurrent use would require each access then to be done under lock. By
using separate entries, we can update a HTTPS entry without needing to
duplicate an existing address entry for the same host+port.
Connection filters can now ask for DNS resolves. This works at any time
during connection setup and while connect is going on.
`Curl_conn_dns_add_addr_resolve()` and
`Curl_conn_dns_add_https_resolve()` are used for that. They check if the
resolve is already ongoing, can be added to a resolve not started yet
or, as last resort, create a new filter instance and add it to the
connection (it's easier to add more filters than making the same filter
handle multiple resolves. Since DNS filters are removed once the
connection is established, there is no later penalty).
HTTPS-RR queries are added by the `HTTPS-CONNECT`, `SSL` and `QUIC`
filters. The latter will only do that when ECH is configured and
supported. That means we trigger HTTPS-RR queries only when the results
matter.
Add test_22_06 for ALPN influenced via HTTPS-RR when tunneling through a
proxy. This did not work before.
Adjust test2100 to use https: as the previous http: URL no longer
triggers HTTPS-RR resolves.
Closes#22216
- enable three checks:
- bugprone-invalid-enum-default-initialization
- bugprone-sizeof-expression
- readability-inconsistent-declaration-parameter-name (strict)
- fix remaining discrepancies with arg names in prototypes
and implementation, in strict mode.
- document reason for some checks tested but not enabled.
Closes#20794
- examples: sync debug output printf masks.
- INSTALL-CMAKE.md: tidy up section for some options.
- curl_sha512_256: delete comment suggesting an optimization.
- vtls/keylog: scope a variable.
- vtls/openssl: make a source code URL a permalink.
- vtls/schannel: drop redundant parentheses.
- test1119.pl: robustify `$1` -> `$s`.
- sync arg names in comments to match the code.
- tidy up and minor fixes to comments.
- fix formatting/indenting/comment/newline/include nits.
- move `UNITTEST` protos next to definitions, sync their argument names.
- make variables static.
- add parentheses to Perl `open()` calls.
- drop unnecessary double quotes in Perl.
- clang-format.
Closes#21000
- allow to specify when they are wanted on starting a resolve
- match dns cache entries accordingly. An entry which never
tried to get HTTPS-RRs is no answer for a resolve that wants
it.
- fix late arrivals of resolve answers to match the "async"
records that started them - if it still exists.
- provide for multiple "async" resolves in a transfer at the
same time. We may need to resolve an IP interface while the
main connection resolve has not finished yet.
- allow lookup of HTTPS-RR information as soon as it is
available, even if A/AAAA queries are still ongoing.
For this, the "async" infrastructure is changed:
- Defined bits for DNS queries `CURL_DNSQ_A`, `CURL_DNSQ_AAAA`
and `CURL_DNSQ_HTTPS`. These replace `ip_version` which says
nothing about HTTPS.
Use them in dns cache entries for matching.
- enhance the `async->id` to be a unique `uint32_t` for
resolves inside one multi. This is weak, as the id may
wrap around. However it is combined with the `mid` of
the easy handle, making collisions highly unlikely.
`data->state.async` is only accessed in few places where
the mid/async-id match is performed.
- vtls: for ECH supporting TLS backends (openssl, rustls, wolfssl),
retrieve the HTTPS-RR information from the dns connection filter.
Delay the connect if the HTTPS-RR is needed, but has not
been resolved yet.
The implementation of all this is complete for the threaded
resolver. c-ares resolver and DoH do not take advantage of
all new async features yet. To be done in separate PRs.
Details:
c-ares: cleanup settings and initialisation. Any ares channel
is only being created on starting a resolve and propagating
operations in setopt.c to the channel are not helpful.
Changed threaded+ares pollset handling so that they do not
overwrite each others `ASYNC_NAME` timeouts.
Add trace name 'threads' for tracing thread queue and
pool used by threaded resolver.
Closes#21175
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
- Rename `Curl_resolv_unlink()` to `Curl_dns_entry_unlink()`.
- Change `Curl_dnscache_get()` to return CURLcode result. Returns
now `CURLE_COULDNT_RESOLVE_HOST` for "negative" cache entries.
- Add `Curl_dnscache_add_negative()` to put a "negative" entry
into the cache.
Closes#20864
