transfer origin and proxy handling

[icing]

transfer origin and proxy handling

Add data->state.origin as the origin the transfer is sending the current request to/gets the response from. Use it for request specific properties like authentication, hsts and cookie handling, etc.

Unless talking to a forwarding HTTP proxy (e.g. not tunneling), data->state.origin and conn->origin are the same. With a forwarding HTTP proxy in play, conn->origin is set to conn->http_proxy.peer and conn->bits.origin_is_proxy (a new bit) is set.

Remove the connection bits, now replaced with:

• conn->bits.socksproxy -> conn->socks_proy.peer
• conn->bits.httpproxy -> conn->http_proy.peer
• conn->bits.proxy -> (conn->socks_proy.peer || conn->http_proy.peer)
• conn->bits.tunnel_proxy -> (conn->http_proy.peer && !conn->bits.origin_is_proxy)
• (conn->bits.httpproxy && !conn->bits.tunnel_proxy) -> conn->bits.origin_is_proxy

Rename noproxy.[ch] to proxy.[ch]. Move the connection proxy setup code from url.c to proxy.c.

Remove data->info.conn_remote_port as no one uses it.

Add test_40_02b for a SOCKS connection to a forwarding HTTPS proxy.

Update internal documentation about peers and creds.

[Copilot]

Pull request overview

This PR refactors how libcurl models “where a request is going” vs “where a connection is established” by introducing data->state.origin (per-request origin) and reworking proxy handling so forwarding HTTP proxies become the connection origin while still preserving the transfer origin for request-scoped logic (auth, HSTS, cookies, etc.).

Changes:

• Add data->state.origin and update request-scoped features (auth/SPN, HSTS upgrades, cookies, alt-svc, AWS SigV4, etc.) to use it instead of conn->origin.
• Consolidate proxy configuration/NO_PROXY parsing into new lib/proxy.[ch], replacing several conn->bits.*proxy* flags with conn->(socks|http)_proxy.peer and conn->bits.origin_is_proxy.
• Add Curl_conn_is_tunneling() and expand tests/docs, including a new SOCKS→forwarding HTTPS-proxy test.

Reviewed changes

Copilot reviewed 30 out of 30 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/unit/unit1614.c	Switch unit test to include proxy.h and call proxy_check_noproxy().
tests/http/test_40_socks.py	Add test coverage for SOCKS to forwarding HTTPS proxy (no tunnel).
lib/vquic/vquic.c	Update SOCKS proxy detection to use conn->socks_proxy.peer.
lib/vauth/vauth.c	Use data->state.origin when deciding if auth is allowed to the current host.
lib/vauth/digest.c	Build SPN from data->state.origin->hostname.
lib/vauth/digest_sspi.c	Build SPN from data->state.origin->hostname (SSPI).
lib/urldata.h	Add data->state.origin, remove legacy proxy bits, move proxy_info to proxy.h.
lib/url.c	Introduce url_set_data_origin_and_creds(), refactor connection/needle setup around data->state.origin, and integrate Curl_proxy_init_conn().
lib/transfer.c	Clear data->state.origin at pretransfer start.
lib/proxy.h	New internal proxy API/types/macros and Curl_proxy_init_conn() declaration.
lib/proxy.c	New consolidated proxy/no_proxy parsing + connection proxy initialization logic.
lib/peer.c	Replace IS_HTTPS_PROXY() with CURL_PROXY_IS_HTTPS().
lib/noproxy.c	Remove old no_proxy implementation (superseded by proxy.c).
lib/Makefile.inc	Swap noproxy.[ch] for proxy.[ch] in build lists.
lib/http2.c	Use data->state.origin for authority checks; treat forwarding proxy via origin_is_proxy.
lib/http.c	Rebase proxy/auth/host/cookie/HSTS/alt-svc behaviors onto data->state.origin + origin_is_proxy.
lib/http_proxy.h	Remove IS_HTTPS_PROXY/IS_QUIC_PROXY macros (moved/replaced).
lib/http_proxy.c	Use origin_is_proxy to select proxy vs server header behavior.
lib/http_ntlm.c	Use data->state.origin->hostname for NTLM host calculations.
lib/http_negotiate.c	Use data->state.origin->hostname for negotiate host calculations.
lib/http_digest.c	Use data->state.origin in digest state flushing.
lib/http_aws_sigv4.c	Use data->state.origin->hostname for signing.
lib/ftp.c	Replace proxy-bit checks with Curl_conn_is_tunneling().
lib/connect.c	Rework proxy filter setup using proxy peers + origin_is_proxy.
lib/cfilters.h	Declare new Curl_conn_is_tunneling().
lib/cfilters.c	Implement Curl_conn_is_tunneling() by checking for CF_TYPE_PROXY filters.
lib/cf-socket.c	Remove unused data->info.conn_remote_port updates.
lib/cf-ip-happy.c	Update proxy-peer selection and peer equality checks.
docs/internals/PEERS.md	Document data->state.origin and forwarding vs tunneling proxy semantics.
docs/internals/CREDENTIALS.md	Update description to use data->state.origin rather than conn->origin.

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