ⓘ Require websocket routes to opt in with allow_basic_ws before Basic auth is accepted in session mode. Mark linked ws-link routes and no-cookie backend-session routes as allowed, while leaving normal session-backed routes unmarked.
This PR adds general WebSocket proxying for linked Webmin servers, allowing modules such as `xterm` to work when opened through `servers/link.cgi`.
As requested in https://github.com/webmin/webmin/issues/1866.
This PR fixes Webmin IP access control handling for IPv6 CIDR prefixes that are not divisible by 8, such as `/29` as mentioned in this https://github.com/webmin/webmin/issues/1570 ticket.
Before Webmin validation rejected non-byte-aligned IPv6 network sizes, and the runtime matcher compared IPv6 networks only by whole bytes. This meant valid IPv6 CIDR prefixes could not be used safely in access control rules.
Changes:
- Allow IPv6 access-control prefixes from `/0` through `/128`, without requiring divisibility by 8.
- Add bit-accurate IPv6 prefix matching for ACL checks.
- Apply the same matching behavior in both `miniserv.pl` and `webmin/webmin-lib.pl`.
- Fix IPv6 canonicalization for `::` and trailing `::` forms used by the matcher.
- Add regression tests for `/0`, `/29`, `/32`, `/63`, `/64`, `/127`, and `/128`.
