lib/src: white space edits to comply better with code style

... as checksrc now finds and complains about these.

Closes #14921

lib: remove the final strncpy() calls

wolfssl: use strcpy() as the target buffer is > 40 bytes

gethostname: return failure if the buffer is too small instead

Closes #14830

wolfssl: fix setting tls version

The value CURL_SSLVERSION_TLSv1_0 was unsupported.

Closes #14587

gnutls/wolfssl: improve error message when certificate fails

Give more detailed reasons for certificate failures where available in
gnutls and wolfssi to allow user to understand the cau

gnutls/wolfssl: improve error message when certificate fails

Give more detailed reasons for certificate failures where available in
gnutls and wolfssi to allow user to understand the cause of the failure.

Closes #14501

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vtls: fix static function name collisions between TLS backends

When using CMake Unity build.

- use unique name for `set_ssl_version_min_max()`
Fixes collision between GnuTLS,

vtls: fix static function name collisions between TLS backends

When using CMake Unity build.

- use unique name for `set_ssl_version_min_max()`
Fixes collision between GnuTLS, mbedTLS and SecureTransport.
```
lib\vtls\mbedtls.c(317,1): error C2084: function 'CURLcode set_ssl_version_min_max(Curl_easy *,ssl_peer *,ssl_primary_config *,const char **,const char *)' already has a body
lib\vtls\mbedtls.c(837,49): warning C4133: 'function': incompatible types - from 'Curl_cfilter *' to 'Curl_easy *'
lib\vtls\mbedtls.c(837,53): warning C4133: 'function': incompatible types - from 'Curl_easy *' to 'ssl_peer *'
lib\vtls\mbedtls.c(837,25): error C2198: 'set_ssl_version_min_max': too few arguments for call
```

- use unique name for `do_file_type()`
Fixes collision between GnuTLS, OpenSSL and wolfSSL.
```
lib\vtls\openssl.c(1053,12): error C2084: function 'gnutls_x509_crt_fmt_t do_file_type(const char *)' already has a body
```

Ref: https://github.com/curl/curl/actions/runs/10341162641/job/28622681573?pr=14484#step:10:31
Cherry-picked from #14495
Closes #14516

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wolfssl: fix CURLOPT_SSLVERSION

Before, setting CURLOPT_SSLVERSION with wolfSSL restricted the the tls
proto to just the specified version. Now it properly supports a range.
So it ca

wolfssl: fix CURLOPT_SSLVERSION

Before, setting CURLOPT_SSLVERSION with wolfSSL restricted the the tls
proto to just the specified version. Now it properly supports a range.
So it can set the min and max tls proto (max requires wolfSSL 4.2.0).

Bump the absolute minimum required version of wolfSSL to 3.4.6 (released
2015) because it is needed for the wolfSSL_CTX_SetMinVersion() function.

Closes #14480

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spnego_gssapi: implement TLS channel bindings for openssl

Channel Bindings are used to tie the session context to a specific TLS
channel. This is to provide additional proof of valid ide

spnego_gssapi: implement TLS channel bindings for openssl

Channel Bindings are used to tie the session context to a specific TLS
channel. This is to provide additional proof of valid identity,
mitigating authentication relay attacks.

Major web servers have the ability to require (None/Accept/Require)
GSSAPI channel binding, rendering Curl unable to connect to such
websites unless support for channel bindings is implemented.

IIS calls this feature Extended Protection (EPA), which is used in
Enterprise environments using Kerberos for authentication.

This change require krb5 >= 1.19, otherwise channel bindings won't be
forwarded through SPNEGO.

Co-Authored-By: Steffen Kieß <947515+steffen-kiess@users.noreply.github.com>
Closes #13098

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wolfssl: avoid taking cached x509 store ref if sslctx already using it

Closes #14442

vtls: add SSLSUPP_CIPHER_LIST

Added SSLSUPP_CIPHER_LIST so be able to differniate SSL Backends
that support CURLOPT_SSL_CIPHER_LIST.

Closes #14406

wolfssl: add CURLOPT_TLS13_CIPHERS support

Bring setting ciphers with WolfSSL in line with other SSL backends,
to make the curl interface more consistent across the backends.

No

wolfssl: add CURLOPT_TLS13_CIPHERS support

Bring setting ciphers with WolfSSL in line with other SSL backends,
to make the curl interface more consistent across the backends.

Now the tls1.3 ciphers are set with the --tls13-ciphers option, when
not set the default tls1.3 ciphers are used. The tls1.2 (1.1, 1.0)
ciphers are set with the --ciphers option, when not set the default
tls1.2 ciphers are used. The ciphers available for the connection
are now a union of the tls1.3 and tls1.2 ciphers.

This changes the behaviour for WolfSSL when --ciphers is set, but
--tls13-ciphers is not set. Now the ciphers set with --ciphers
are combined with the default tls1.3 ciphers, whereas before solely
the ciphers of --ciphers were used.

Thus before when no tls1.3 ciphers were specified in --ciphers,
tls1.3 was completely disabled. This might not be what the user
expected, especially as this does not happen with OpenSSL.

Closes #14385

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wolfssl: improve shutdown handling

Improve handling of shutdown when sending gets blocked.

Add workaround for <https://github.com/wolfSSL/wolfssl/issues/7784>
where wolfSSL keep

wolfssl: improve shutdown handling

Improve handling of shutdown when sending gets blocked.

Add workaround for <https://github.com/wolfSSL/wolfssl/issues/7784>
where wolfSSL keeps on adding close notify messages to its outgoing
buffer on ever attempt.

Closes #14376

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wolfssl: add support for ssl cert blob / ssl key blob options

wolfSSL supports setting certificates/private keys from memory blobs
which allow us to implement both CURLOPT_SSLCERT_BLOB a

wolfssl: add support for ssl cert blob / ssl key blob options

wolfSSL supports setting certificates/private keys from memory blobs
which allow us to implement both CURLOPT_SSLCERT_BLOB and
CURLOPT_SSLKEY_BLOB options.

Closes #14018

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lib: add eos flag to send methods

Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will

lib: add eos flag to send methods

Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers
are not yet fully flushed.

Closes #14220

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url: dns_entry related improvements

Replace Curl_resolv_unlock() with Curl_resolv_unlink():

-replace inuse member with refcount in Curl_dns_entry

- pass Curl_dns_entry ** t

url: dns_entry related improvements

Replace Curl_resolv_unlock() with Curl_resolv_unlink():

-replace inuse member with refcount in Curl_dns_entry

- pass Curl_dns_entry ** to unlink, so it gets always cleared

- solve potential (but unlikley) UAF in FTP's handling of looked up
Curl_dns_entry. Esp. do not use addr information after unlinking an entry.
In reality, the unlink will not free memory, as the dns entry is still
referenced by the hostcache. But this is not safe and relying on no other
code pruning the cache in the meantime.

- pass permanent flag when adding a dns entry instead of fixing timestamp
afterwards.

url.c: fold several static *resolve_* functions into one.

Closes #14195

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wolfssl: avoid calling get_cached_x509_store if store is uncachable

There's no need for get_cached_x509_store call if the return value won't
be used for caching anyway.

Closes #

wolfssl: avoid calling get_cached_x509_store if store is uncachable

There's no need for get_cached_x509_store call if the return value won't
be used for caching anyway.

Closes #14306

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wolfssl: CA store share fix

When sharing the x509 store in wolfSSL, always use an explicitly
constructed one, as the SSLCTX might have "only" an internal one which
is not obeying ref

wolfssl: CA store share fix

When sharing the x509 store in wolfSSL, always use an explicitly
constructed one, as the SSLCTX might have "only" an internal one which
is not obeying reference count lifetimes.

Fixes #14278
Reported-by: Alex Snast
Closes #14279

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wolfSSL: allow wolfSSL's implementation of kyber to be used

Closes #14268

Revert "lib: send eos flag"

This reverts commit be93299f10ef0b2bf7fe5c82140120073831867a.

lib: send eos flag

Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol

lib: send eos flag

Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers are
not yet fully flushed.

Closes #14220

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GHA/windows: add MSVC wolfSSL job with test

Fix the file of wolfssl.c because of this warning/error:
```
curl\lib\vtls\wolfssl.c(1017,42): error C2220: the following warning is treat

GHA/windows: add MSVC wolfSSL job with test

Fix the file of wolfssl.c because of this warning/error:
```
curl\lib\vtls\wolfssl.c(1017,42): error C2220: the following warning is treated as an error [curl\bld\lib\libcurl_object.vcxproj]
curl\lib\vtls\wolfssl.c(1017,42): warning C4267: 'function': conversion from 'size_t' to 'unsigned long', possible loss of data [curl\bld\lib\libcurl_object.vcxproj]
```

`size_t` in MSVC is different. Change it to `unsigned long` because
`wolfSSL_ERR_error_string_n` last argument is defined as
`unsigned long`.

Closes #14193

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tidy-up: adjust casing of project names

Mostly TLS/SSH project name.

Closes #14160

wolfssl: use larger error buffer when formatting errors

Currently we're using WOLFSSL_MAX_ERROR_SZ to define the error buffer
size, this value is user defined which means it can be overw

wolfssl: use larger error buffer when formatting errors

Currently we're using WOLFSSL_MAX_ERROR_SZ to define the error buffer
size, this value is user defined which means it can be overwritten with
-DWOLFSSL_MAX_ERROR_SZ=512 when building wolfssl and this overwrite is
not exported to the users of wolfssl.

Instead of relying on WOLFSSL_MAX_ERROR_SZ we'll just use a 256 bytes
error buffer and use wolfSSL_ERR_error_string_n to fill it thus dropping
the dependency on WOLFSSL_MAX_ERROR_SZ altogether.

Closes #14114

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vtls: replace addsessionid with set_sessionid

- deduplicate the code in many tls backends that check
for an existing id and delete it before adding the new one
- rename ssl_primary

vtls: replace addsessionid with set_sessionid

- deduplicate the code in many tls backends that check
for an existing id and delete it before adding the new one
- rename ssl_primary_config's `sessionid` bool to `cache_session`

Closes #14121

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code: language cleanup in comments

Based on the standards and guidelines we use for our documentation.

- expand contractions (they're => they are etc)
- host name = > hostname

code: language cleanup in comments

Based on the standards and guidelines we use for our documentation.

- expand contractions (they're => they are etc)
- host name = > hostname
- file name => filename
- user name = username
- man page => manpage
- run-time => runtime
- set-up => setup
- back-end => backend
- a HTTP => an HTTP
- Two spaces after a period => one space after period

Closes #14073

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lib: graceful connection shutdown

When libcurl discards a connection there are two phases this may go
through: "shutdown" and "closing". If a connection is aborted, the
shutdown phas

lib: graceful connection shutdown

When libcurl discards a connection there are two phases this may go
through: "shutdown" and "closing". If a connection is aborted, the
shutdown phase is skipped and it is closed right away.

The connection filters attached to the connection implement the phases
in their `do_shutdown()` and `do_close()` callbacks. Filters carry now a
`shutdown` flags next to `connected` to keep track of the shutdown
operation.

Filters are shut down from top to bottom. If a filter is not connected,
its shutdown is skipped. Notable filters that *do* something during
shutdown are HTTP/2 and TLS. HTTP/2 sends the GOAWAY frame. TLS sends
its close notify and expects to receive a close notify from the server.

As sends and receives may EAGAIN on the network, a shutdown is often not
successful right away and needs to poll the connection's socket(s). To
facilitate this, such connections are placed on a new shutdown list
inside the connection cache.

Since managing this list requires the cooperation of a multi handle,
only the connection cache belonging to a multi handle is used. If a
connection was in another cache when being discarded, it is removed
there and added to the multi's cache. If no multi handle is available at
that time, the connection is shutdown and closed in a one-time,
best-effort attempt.

When a multi handle is destroyed, all connection still on the shutdown
list are discarded with a final shutdown attempt and close. In curl
debug builds, the environment variable `CURL_GRACEFUL_SHUTDOWN` can be
set to make this graceful with a timeout in milliseconds given by the
variable.

The shutdown list is limited to the max number of connections configured
for a multi cache. Set via CURLMOPT_MAX_TOTAL_CONNECTIONS. When the
limit is reached, the oldest connection on the shutdown list is
discarded.

- In multi_wait() and multi_waitfds(), collect all connection caches
involved (each transfer might carry its own) into a temporary list.
Let each connection cache on the list contribute sockets and
POLLIN/OUT events it's connections are waiting for.

- in multi_perform() collect the connection caches the same way and let
them peform their maintenance. This will make another non-blocking
attempt to shutdown all connections on its shutdown list.

- for event based multis (multi->socket_cb set), add the sockets and
their poll events via the callback. When `multi_socket()` is invoked
for a socket not known by an active transfer, forward this to the
multi's cache for processing. On closing a connection, remove its
socket(s) via the callback.

TLS connection filters MUST NOT send close nofity messages in their
`do_close()` implementation. The reason is that a TLS close notify
signals a success. When a connection is aborted and skips its shutdown
phase, the server needs to see a missing close notify to detect
something has gone wrong.

A graceful shutdown of FTP's data connection is performed implicitly
before regarding the upload/download as complete and continuing on the
control connection. For FTP without TLS, there is just the socket close
happening. But with TLS, the sent/received close notify signals that the
transfer is complete and healthy. Servers like `vsftpd` verify that and
reject uploads without a TLS close notify.

- added test_19_* for shutdown related tests
- test_19_01 and test_19_02 test for TCP RST packets
which happen without a graceful shutdown and should
no longer appear otherwise.
- add test_19_03 for handling shutdowns by the server
- add test_19_04 for handling shutdowns by curl
- add test_19_05 for event based shutdowny by server
- add test_30_06/07 and test_31_06/07 for shutdown checks
on FTP up- and downloads.

Closes #13976

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