Describe the feature you'd like to add to nginx

Add transparent parameter support for the HTTP module's listen directive, similar to the existing implementation in the stream module.

Proposed syntax:

http {
    server {
        listen 80 transparent;
        listen [::]:80 transparent;
        
        location / {
            proxy_bind $remote_addr transparent;
            proxy_pass http://$host;
        }
    }
}

Describe the problem this feature solves

Currently, deploying nginx as a transparent HTTP proxy or Web Application Firewall (WAF) in bridge mode is not possible because the HTTP listen directive lacks transparent support.

The deployment scenario:

Client → [iptables TPROXY] → nginx → upstream/origin server

Additional context

I have reviewed the nginx source code and found that implementing this feature is straightforward, as most of the infrastructure already exists:

1，NGX_HAVE_TRANSPARENT_PROXY feature detection is already in place ( auto/unix )
2，IP_TRANSPARENT / IP_BINDANY / SO_BINDANY socket options are already used in ngx_event_connect.c
3，proxy_bind transparent is already supported in the HTTP upstream module
4，The stream module's implementation can serve as a reference

Final

I have implemented this feature in our internal fork and would be happy to contribute a patch if the nginx team is interested. Please let me know if there are any design considerations or concerns I should be aware of.