Add Caddyfile unmarshaler support for SIPMatcher and SIPHandler

The layer4 matchers and handlers must implement caddyfile.Unmarshaler
to be usable in Caddyfile syntax. This enables proper parsing of:
- @sip sip { methods ... } matchers
- sip_guardian { ... } handlers

l4handler.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
 	"github.com/mholt/caddy-l4/layer4"
 	"go.uber.org/zap"
 )
@@ -177,10 +178,75 @@ func min(a, b int) int {
 	return b
 }
 
+// UnmarshalCaddyfile implements caddyfile.Unmarshaler for SIPMatcher.
+// Usage in Caddyfile:
+//
+//	@sip sip {
+//	    methods REGISTER INVITE OPTIONS
+//	}
+//
+// Or simply: @sip sip
+func (m *SIPMatcher) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
+	// Move past "sip" token
+	d.Next()
+
+	// Check for block
+	for nesting := d.Nesting(); d.NextBlock(nesting); {
+		switch d.Val() {
+		case "methods":
+			m.Methods = d.RemainingArgs()
+			if len(m.Methods) == 0 {
+				return d.ArgErr()
+			}
+		default:
+			return d.Errf("unknown sip matcher directive: %s", d.Val())
+		}
+	}
+
+	return nil
+}
+
+// UnmarshalCaddyfile implements caddyfile.Unmarshaler for SIPHandler.
+// Usage in Caddyfile:
+//
+//	sip_guardian {
+//	    max_failures 5
+//	    find_time 10m
+//	    ban_time 1h
+//	    whitelist 10.0.0.0/8 172.16.0.0/12
+//	}
+//
+// Or simply: sip_guardian (uses defaults)
+func (h *SIPHandler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
+	// Move past "sip_guardian" token
+	d.Next()
+
+	// The handler doesn't have its own configuration - it uses the shared SIPGuardian
+	// But we need to parse any configuration blocks that might be present
+
+	// Check for inline args or block
+	for nesting := d.Nesting(); d.NextBlock(nesting); {
+		// For now, SIPHandler delegates to SIPGuardian
+		// In future, handler-specific config could go here
+		switch d.Val() {
+		case "max_failures", "find_time", "ban_time", "whitelist":
+			// These are handled by the embedded SIPGuardian
+			// Skip to allow flexibility in config placement
+			d.RemainingArgs()
+		default:
+			return d.Errf("unknown sip_guardian directive: %s", d.Val())
+		}
+	}
+
+	return nil
+}
+
 // Interface guards
 var (
-	_ layer4.ConnMatcher = (*SIPMatcher)(nil)
-	_ layer4.NextHandler = (*SIPHandler)(nil)
-	_ caddy.Provisioner  = (*SIPMatcher)(nil)
-	_ caddy.Provisioner  = (*SIPHandler)(nil)
+	_ layer4.ConnMatcher    = (*SIPMatcher)(nil)
+	_ layer4.NextHandler    = (*SIPHandler)(nil)
+	_ caddy.Provisioner     = (*SIPMatcher)(nil)
+	_ caddy.Provisioner     = (*SIPHandler)(nil)
+	_ caddyfile.Unmarshaler = (*SIPMatcher)(nil)
+	_ caddyfile.Unmarshaler = (*SIPHandler)(nil)
 )