"asyn" is the internal name under which both c-ares and threaded
resolver operate. Make the naming more consistent. Implement the c-ares
resolver in `asyn-ares.*` and the threaded resolver in `asyn-thrdd.*`.
The common functions are in `asyn-base.c`.
When `CURLRES_ASYNCH` is defined, either of the two is used and
`data->state.async` exists. Members of that struct vary for the selected
implementation, but have the fields `hostname`, `port` and `ip_version`
always present. This are populated when the async resolving starts and
eliminate the need to pass them again when checking on the status and
processing the results of the resolving.
Add a `Curl_resolv_blocking()` to `hostip.h` that relieves FTP and SOCKS
from having to repeat the same code.
`Curl_resolv_check()` remains the function to check for status of
ongoing resolving. Now it also performs internally the check if the
needed DNS entry exists in the dnscache and if so, aborts the asnyc
operation. (libcurl right now does not check for duplicate resolve
attempts. an area for future improvements).
The number of functions in `asyn.h` has been reduced. There were subtle
difference in "cancel()" and "kill()" calls, both replaced by
`Curl_async_shutdown()` now. This changes behaviour for threaded
resolver insofar as the resolving thread is now always joined unless
`data->set.quick_exit` is set. Before this was only done on some code
paths. A future improvement would be a thread pool that keeps a limit
and also could handle joins more gracefully.
DoH, not previously tagged under "asny", has its struct `doh_probes` now
also in `data->state.async`, moved there from `data->req` because it
makes more sense. Further integration of DoH underneath the "asyn"
umbrella seems like a good idea.
Closes#16963
when CURLMOPT_MAX_HOST_CONNECTIONS or CURLMOPT_MAX_TOTAL_CONNECTIONS
limits are reached, force close connections in shutdown to go below
limit when possible.
Fixes#17020
Reported-by: Fujii Hironori
Closes#17022
Slight refactoring around dnscache, e.g. hostcache
- eliminate `data->state.hostcache`. Always look up
relevant dnscache at share/multi.
- unify naming to "dnscache", replacing "hostcache"
- use `struct Curl_dnscache`, even though it just
contains a `Curl_hash` for now.
- add `Curl_dnscache_destroy()` for cleanup in
share/multi.
Closes#16941
Further testing with timeouts in event based processing revealed that
our current shutdown handling in the connection pool was not clear
enough. Graceful shutdowns can only happen inside a multi handle and it
was confusing to track in the code which situation actually applies. It
seems better to split the shutdown handling off and have that code
always be part of a multi handle.
Add `cshutdn.[ch]` with its own struct to maintain connections being
shut down. A `cshutdn` always belongs to a multi handle and uses that
for socket/timeout monitoring.
The `cpool`, which can be part of a multi or share, either passes
connections to a `cshutdn` or terminates them with a one-time, best
effort.
Add an `admin` easy handle to each multi and share. This is used to
perform all maintenance operations where no "real" easy handle is
available. This solves the problem that the multi admin handle requires
some additional initialisation (e.g. timeout list).
The share needs its admin handle as it is often cleaned up when no other
transfer or multi handle exists any more. But we need a `data` in almost
every call.
Fix file:// handling of errors when adding a new connection to the pool.
Changes in `curl` itself:
- for parallel transfers, do not set a connection pool in the share,
rely on the multi's connection pool instead. While not a requirement
for the new `cshutdn` to work, this is
a) helpful in testing to trigger graceful shutdowns
b) a broader code coverage of libcurl via the curl tool
- on test_event with uv, cleanup the multi handle before returning from
parallel_event(). The uv struct is on the stack, cleanup of the multi
later will crash when it tries to register sockets. This is a "eat
your own dogfood" related fix.
Closes#16508
