httpserver: Fix address display and routing for IPv6 IPs/wildcards

caddyhttp/httpserver/plugin.go

@@ -428,11 +428,12 @@ func (a Address) String() string {
 	if s != "" {
 		s += "://"
 	}
-	s += a.Host
 	if a.Port != "" &&
 		((scheme == "https" && a.Port != DefaultHTTPSPort) ||
 			(scheme == "http" && a.Port != DefaultHTTPPort)) {
-		s += ":" + a.Port
+		s += net.JoinHostPort(a.Host, a.Port)
+	} else {
+		s += a.Host
 	}
 	if a.Path != "" {
 		s += a.Path

caddyhttp/httpserver/vhosttrie.go

@@ -32,7 +32,12 @@ type vhostTrie struct {
 
 // newVHostTrie returns a new vhostTrie.
 func newVHostTrie() *vhostTrie {
-	return &vhostTrie{edges: make(map[string]*vhostTrie), fallbackHosts: []string{"0.0.0.0", ""}}
+	// TODO: fallbackHosts doesn't discriminate between network interfaces;
+	// i.e. if there is a host "0.0.0.0", it could match a request coming
+	// in to "[::1]" (and vice-versa) even though the IP versions differ.
+	// This might be OK, or maybe it's not desirable. The 'bind' directive
+	// can be used to restrict what interface a listener binds to.
+	return &vhostTrie{edges: make(map[string]*vhostTrie), fallbackHosts: []string{"0.0.0.0", "[::]", ""}}
 }
 
 // Insert adds stack to t keyed by key. The key should be