Struct HostFilter 

pub struct HostFilter { /* private fields */ }

A filter for host-based network access control.

Supports exact domain match and wildcard subdomains (*.googleapis.com).

Cloud metadata endpoints are always denied and cannot be overridden. The allowlist determines which hosts are permitted; everything else is denied by default.

Implementations

impl HostFilter

pub fn new(allowed_hosts: &[String]) -> Self

Create a new host filter with the given allowed hosts.

Cloud metadata endpoints are automatically denied and cannot be removed.

Hosts starting with *. are treated as wildcard subdomain patterns. All other entries are exact matches. Matching is case-insensitive.

pub fn allow_all() -> Self

Create a host filter that allows everything (no filtering).

Cloud metadata endpoints are still blocked.

pub fn check_host(&self, host: &str, resolved_ips: &[IpAddr]) -> FilterResult

Check a host against the filter.

resolved_ips should contain the DNS-resolved IP addresses for the host. The caller is responsible for performing DNS resolution before calling this method. This prevents DNS rebinding attacks: the proxy resolves once, checks the resolved IPs here, then connects to the same resolved IP.

Check Order

1. Deny hosts (exact match against cloud metadata hostnames)
2. Link-local IP check (resolved IPs in 169.254.0.0/16 or fe80::/10)
3. Allowlist (exact host match, then wildcard subdomain match)
4. Default deny (if not in allowlist and allowlist is non-empty)

pub fn allowed_count(&self) -> usize

Number of allowed hosts (exact + wildcard)

Trait Implementations

impl Clone for HostFilter

fn clone(&self) -> HostFilter

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HostFilter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.