Propagate XFCC header to the backend

[arkodg]

Description:

Describe the desired behavior, what scenario it enables and how it
would be used.

Propagate the XFCC header to the client after validating the client via mutual TLS
https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/network/http_connection_manager/v3/http_connection_manager.proto#enum-extensions-filters-network-http-connection-manager-v3-httpconnectionmanager-forwardclientcertdetails

Decisions

1. Defaults / Opt in or opt out

2. Where should it live

a) https://gateway.envoyproxy.io/latest/api/extension_types/#headersettings
or
b) https://gateway.envoyproxy.io/latest/api/extension_types/#clientvalidationcontext

• feat: support forward client cert config XFCC header #3202
• Docs: XFCC
• E2E: XFCC

[zufardhiyaulhaq]

how expensive is the computing process if we opt-in for the XFCC?

this can also being used later in the authorization API
#2652

[zufardhiyaulhaq]

@arkodg please assign this to me, thanks

[zirain]

/assign zufardhiyaulhaq

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days.

[zufardhiyaulhaq]

no stale