API for WEB: bounded lifecycle and overload observability added

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>

src/config/load/strict_keys.rs

@@ -265,6 +265,7 @@ const WEB_CONFIG_KEYS: &[&str] = &[
     "carriers",
     "carrier_learning",
     "carrier_negotiation_aggressiveness",
+    "http_connection_capacity_action",
     "debug",
     "limits",
     "timeouts",
@@ -278,6 +279,7 @@ const WEB_LIMITS_CONFIG_KEYS: &[&str] = &[
     "carrier_batch_bytes",
     "max_frames_per_body",
     "max_http_connections",
+    "max_http_overload_connections",
     "max_http_handlers",
     "max_lane_open_waits_per_session",
     "pending_bytes_per_lane",
@@ -354,6 +356,7 @@ const WEB_TIMEOUTS_CONFIG_KEYS: &[&str] = &[
     "bootstrap_lifetime_secs",
     "reconnect_grace_secs",
     "http_idle_secs",
+    "http_overload_timeout_ms",
     "shutdown_secs",
     "decoy_header_secs",
 ];

src/config/load/validate_web.rs

@@ -83,9 +83,59 @@ pub(super) fn validate(config: &mut ProxyConfig) -> Result<()> {
     timeouts::validate(&config.web.timeouts)?;
     websocket::validate(&carriers, &config.web.limits, &config.web.timeouts)?;
     validate_vhosts(config)?;
+    validate_decoy_listener_separation(config)?;
     Ok(())
 }
 
+/// Rejects a direct decoy recursion into an effective WEB listener.
+pub(super) fn validate_decoy_listener_separation(config: &ProxyConfig) -> Result<()> {
+    let web_listeners = config
+        .server
+        .listeners
+        .iter()
+        .filter(|listener| listener.transport == ListenerTransport::Web)
+        .filter(|listener| {
+            (listener.ip.is_ipv4() && config.network.ipv4)
+                || (listener.ip.is_ipv6() && config.network.ipv6 != Some(false))
+        })
+        .map(|listener| SocketAddr::new(listener.ip, listener.port.unwrap_or(config.server.port)))
+        .collect::<Vec<_>>();
+    for (vhost_idx, vhost) in config.web.vhosts.iter().enumerate() {
+        let WebDecoyConfig::HttpUpstream { upstream } = &vhost.decoy else {
+            continue;
+        };
+        let parsed = url::Url::parse(upstream).map_err(|error| {
+            ProxyError::Config(format!(
+                "web.vhosts[{vhost_idx}].decoy.upstream is invalid: {error}"
+            ))
+        })?;
+        let Some(port) = parsed.port_or_known_default() else {
+            continue;
+        };
+        let upstream_ip = match parsed.host() {
+            Some(url::Host::Ipv4(ip)) => IpAddr::V4(ip),
+            Some(url::Host::Ipv6(ip)) => IpAddr::V6(ip),
+            _ => continue,
+        };
+        let upstream_addr = SocketAddr::new(upstream_ip, port);
+        if web_listeners
+            .iter()
+            .any(|listener| listener_covers(*listener, upstream_addr))
+        {
+            return config_error(&format!(
+                "web.vhosts[{vhost_idx}].decoy upstream overlaps WEB listener {upstream_addr}"
+            ));
+        }
+    }
+    Ok(())
+}
+
+fn listener_covers(listener: SocketAddr, target: SocketAddr) -> bool {
+    listener.port() == target.port()
+        && (listener.ip() == target.ip()
+            || (listener.ip().is_unspecified() && listener.is_ipv4() == target.is_ipv4()))
+}
+
 fn validate_web_listener(
     config: &ProxyConfig,
     idx: usize,
@@ -169,6 +219,10 @@ fn validate_limits(limits: &WebLimitsConfig) -> Result<()> {
 
     let positive = [
         ("max_http_connections", limits.max_http_connections),
+        (
+            "max_http_overload_connections",
+            limits.max_http_overload_connections,
+        ),
         ("max_http_handlers", limits.max_http_handlers),
         (
             "max_lane_open_waits_per_session",
@@ -222,6 +276,10 @@ fn validate_limits(limits: &WebLimitsConfig) -> Result<()> {
     }
     for (field, value) in [
         ("max_http_connections", limits.max_http_connections),
+        (
+            "max_http_overload_connections",
+            limits.max_http_overload_connections,
+        ),
         ("max_http_handlers", limits.max_http_handlers),
         ("max_body_readers", limits.max_body_readers),
         ("max_body_bytes_global", limits.max_body_bytes_global),

src/config/load/validate_web/memory.rs

@@ -5,6 +5,7 @@ const WEB_DEBUG_STATUS_PAGE_BYTES: usize = 8 * 1024 * 1024;
 const WEB_DEBUG_GROUP_SCRATCH_BYTES: usize = 4 * 1024 * 1024;
 const WEB_CARRIER_LEARNING_ENTRY_BYTES: usize = 512;
 const WEB_LANE_STATE_BYTES: usize = 512;
+const WEB_OVERLOAD_CONNECTION_BYTES: usize = 4 * 1024;
 
 /// Validates process-wide body, header, queue, static, and debug reservations.
 pub(super) fn validate(limits: &WebLimitsConfig) -> Result<()> {
@@ -30,6 +31,12 @@ pub(super) fn validate(limits: &WebLimitsConfig) -> Result<()> {
         .ok_or_else(|| {
             ProxyError::Config("web.limits HTTP header reservations overflow usize".to_string())
         })?;
+    let overload_connection_reservation = limits
+        .max_http_overload_connections
+        .checked_mul(WEB_OVERLOAD_CONNECTION_BYTES)
+        .ok_or_else(|| {
+            ProxyError::Config("web.limits HTTP overload reservations overflow usize".to_string())
+        })?;
     let debug_ring_index = limits
         .debug_records_capacity
         .checked_mul(std::mem::size_of::<usize>())
@@ -77,6 +84,7 @@ pub(super) fn validate(limits: &WebLimitsConfig) -> Result<()> {
         .and_then(|value| value.checked_add(carrier_learning_reservation))
         .and_then(|value| value.checked_add(lane_state_reservation))
         .and_then(|value| value.checked_add(http_header_reservation))
+        .and_then(|value| value.checked_add(overload_connection_reservation))
         .ok_or_else(|| ProxyError::Config("web.limits byte ceilings overflow usize".to_string()))?;
     if reserved > limits.memory_envelope_bytes
         || limits.memory_envelope_bytes > MAX_WEB_MEMORY_ENVELOPE_BYTES

src/config/load/validate_web/timeouts.rs

@@ -2,6 +2,9 @@ use super::*;
 
 /// Validates WEB request, learning, and lifecycle timeouts.
 pub(super) fn validate(timeouts: &WebTimeoutsConfig) -> Result<()> {
+    if !(1..=60_000).contains(&timeouts.http_overload_timeout_ms) {
+        return config_error("web.timeouts.http_overload_timeout_ms must be within [1, 60000]");
+    }
     let values = [
         ("header_secs", timeouts.header_secs),
         ("body_secs", timeouts.body_secs),