pytest: add SOCKS tests and scoring

[icing]

Configure curl with --with-test-sockd=<path to sockd> for a locally installed dante sockd server and new test_40_* will verify that down- and uploads work via SOCKS.

Invoke scorecard.py with --socks4 or --socks5 to run performance tests with SOCKS. Note that SOCKS is not supported for HTTP/3.

refs #17969

[icing]

Tested on my macOS dev machine with the following results:

Version: curl 8.15.1-DEV (x86_64-apple-darwin24.5.0) libcurl/8.15.1-DEV OpenSSL/3.5.0 zlib/1.2.12 brotli/1.1.0 zstd/1.5.7 libidn2/2.3.8 libpsl/0.21.5 libssh2/1.11.1 nghttp2/1.65.0 ngtcp2/1.12.0 nghttp3/1.10.1 librtmp/2.3 libgsasl/2.2.2
Features: alt-svc AsynchDNS brotli Debug gsasl GSS-API HSTS HTTP2 HTTP3 HTTPS-proxy HTTPSRR IDN IPv6 Kerberos Largefile libz NTLM PSL SPNEGO SSL SSLS-EXPORT threadsafe TLS-SRP TrackMemory UnixSockets zstd


Downloads from httpd/2.4.64
   size    single [cpu/rss]      serial(50) [cpu/rss]      parallel(50x50) [cpu/rss]
    1MB   11 MB/s [82.6%/4MB]      317 MB/s [87.5%/8MB]           261 MB/s [96.8%/17MB]
   10MB  103 MB/s [84.8%/4MB]      774 MB/s [94.4%/11MB]          963 MB/s [99.2%/25MB]
  100MB  506 MB/s [93.7%/8MB]      976 MB/s [98.0%/11MB]         1349 MB/s [99.8%/26MB]
Downloads from httpd/2.4.64via ['--socks4', '127.0.0.1:52517']
   size    single [cpu/rss]      serial(50) [cpu/rss]      parallel(50x50) [cpu/rss]
    1MB   10 MB/s [79.3%/3MB]      312 MB/s [83.8%/8MB]           238 MB/s [91.7%/17MB]
   10MB   98 MB/s [86.6%/4MB]      845 MB/s [93.1%/11MB]          866 MB/s [99.2%/25MB]
  100MB  542 MB/s [92.5%/8MB]     1020 MB/s [95.5%/10MB]         1240 MB/s [99.5%/26MB]
Downloads from httpd/2.4.64via ['--socks5', '127.0.0.1:52840']
   size    single [cpu/rss]      serial(50) [cpu/rss]      parallel(50x50) [cpu/rss]
    1MB   10 MB/s [81.0%/3MB]      318 MB/s [83.3%/8MB]           234 MB/s [92.4%/17MB]
   10MB  101 MB/s [84.9%/3MB]      817 MB/s [92.8%/11MB]          920 MB/s [99.2%/24MB]
  100MB  528 MB/s [93.1%/8MB]      997 MB/s [95.6%/11MB]         1241 MB/s [99.6%/26MB]

Uploads to httpd/2.4.64
   size    single [cpu/rss]      serial(50) [cpu/rss]      parallel(50x50) [cpu/rss]
    1MB   11 MB/s [82.4%/3MB]      306 MB/s [92.3%/8MB]           248 MB/s [97.0%/16MB]
   10MB   98 MB/s [88.3%/4MB]      725 MB/s [97.9%/10MB]          775 MB/s [99.6%/20MB]
  100MB  526 MB/s [96.3%/8MB]      937 MB/s [99.7%/10MB]         1051 MB/s [99.9%/21MB]
Uploads to httpd/2.4.64 via ['--socks4', '127.0.0.1:53329']
   size    single [cpu/rss]      serial(50) [cpu/rss]      parallel(50x50) [cpu/rss]
    1MB   10 MB/s [81.1%/3MB]      297 MB/s [89.4%/8MB]           229 MB/s [94.0%/16MB]
   10MB  102 MB/s [83.0%/3MB]      722 MB/s [97.1%/10MB]          790 MB/s [99.5%/19MB]
  100MB  504 MB/s [96.3%/8MB]      914 MB/s [99.6%/10MB]          978 MB/s [99.8%/21MB]
Uploads to httpd/2.4.64 via ['--socks5', '127.0.0.1:53653']
   size    single [cpu/rss]      serial(50) [cpu/rss]      parallel(50x50) [cpu/rss]
    1MB   10 MB/s [81.8%/3MB]      284 MB/s [90.6%/8MB]           217 MB/s [92.3%/16MB]
   10MB  102 MB/s [85.0%/3MB]      735 MB/s [97.1%/10MB]          790 MB/s [99.3%/20MB]
  100MB  503 MB/s [96.4%/8MB]      900 MB/s [99.6%/10MB]          986 MB/s [99.8%/21MB]

[vszakats]

sockd init logic for CMake (untested):

diff --git a/docs/INSTALL-CMAKE.md b/docs/INSTALL-CMAKE.md
index 6f8a914d73..7fe8d1db2e 100644
--- a/docs/INSTALL-CMAKE.md
+++ b/docs/INSTALL-CMAKE.md
@@ -463,6 +463,7 @@ Details via CMake
 - `CADDY`:                                  Default: `caddy`
 - `HTTPD_NGHTTPX`:                          Default: `nghttpx`
 - `HTTPD`:                                  Default: `apache2`
+- `SOCKD`:                                  Default: `sockd`
 - `TEST_NGHTTPX`:                           Default: `nghttpx`
 - `VSFTPD`:                                 Default: `vsftps`
 
diff --git a/tests/http/CMakeLists.txt b/tests/http/CMakeLists.txt
index 0c2d65f17f..5e415cbe7c 100644
--- a/tests/http/CMakeLists.txt
+++ b/tests/http/CMakeLists.txt
@@ -52,5 +52,11 @@ if(NOT HTTPD_NGHTTPX)
 endif()
 mark_as_advanced(HTTPD_NGHTTPX)
 
-# Consumed variables: APXS, CADDY, HTTPD, HTTPD_NGHTTPX, VSFTPD
+find_program(SOCKD "sockd")
+if(NOT SOCKD)
+  set(SOCKD "")
+endif()
+mark_as_advanced(SOCKD)
+
+# Consumed variables: APXS, CADDY, HTTPD, HTTPD_NGHTTPX, SOCKD, VSFTPD
 configure_file("config.ini.in" "${CMAKE_CURRENT_BINARY_DIR}/config.ini" @ONLY)

[icing]

Thanks, applied.