Initial support for multiple server names (#2829)

This PR is the first step towards virtual hosting by laying the
groundwork for multiple server names being configured.

3 files changed, 17 insertions, 2 deletions

diff --git a/setup/config/config_global.go b/setup/config/config_global.go
index 784893d2..82577282 100644
--- a/setup/config/config_global.go
+++ b/setup/config/config_global.go
@@ -14,6 +14,9 @@ type Global struct {
 	// The name of the server. This is usually the domain name, e.g 'matrix.org', 'localhost'.
 	ServerName gomatrixserverlib.ServerName `yaml:"server_name"`
 
+	// The secondary server names, used for virtual hosting.
+	SecondaryServerNames []gomatrixserverlib.ServerName `yaml:"-"`
+
 	// Path to the private key which will be used to sign requests and events.
 	PrivateKeyPath Path `yaml:"private_key"`
 
@@ -120,6 +123,18 @@ func (c *Global) Verify(configErrs *ConfigErrors, isMonolith bool) {
 	c.Cache.Verify(configErrs, isMonolith)
 }
 
+func (c *Global) IsLocalServerName(serverName gomatrixserverlib.ServerName) bool {
+	if c.ServerName == serverName {
+		return true
+	}
+	for _, secondaryName := range c.SecondaryServerNames {
+		if secondaryName == serverName {
+			return true
+		}
+	}
+	return false
+}
+
 type OldVerifyKeys struct {
 	// Path to the private key.
 	PrivateKeyPath Path `yaml:"private_key"`
diff --git a/setup/mscs/msc2836/msc2836.go b/setup/mscs/msc2836/msc2836.go
index 452b1458..98502f5c 100644
--- a/setup/mscs/msc2836/msc2836.go
+++ b/setup/mscs/msc2836/msc2836.go
@@ -132,7 +132,7 @@ func Enable(
 	base.PublicFederationAPIMux.Handle("/unstable/event_relationships", httputil.MakeExternalAPI(
 		"msc2836_event_relationships", func(req *http.Request) util.JSONResponse {
 			fedReq, errResp := gomatrixserverlib.VerifyHTTPRequest(
-				req, time.Now(), base.Cfg.Global.ServerName, keyRing,
+				req, time.Now(), base.Cfg.Global.ServerName, base.Cfg.Global.IsLocalServerName, keyRing,
 			)
 			if fedReq == nil {
 				return errResp
diff --git a/setup/mscs/msc2946/msc2946.go b/setup/mscs/msc2946/msc2946.go
index a92a16a2..bc9df0f9 100644
--- a/setup/mscs/msc2946/msc2946.go
+++ b/setup/mscs/msc2946/msc2946.go
@@ -64,7 +64,7 @@ func Enable(
 	fedAPI := httputil.MakeExternalAPI(
 		"msc2946_fed_spaces", func(req *http.Request) util.JSONResponse {
 			fedReq, errResp := gomatrixserverlib.VerifyHTTPRequest(
-				req, time.Now(), base.Cfg.Global.ServerName, keyRing,
+				req, time.Now(), base.Cfg.Global.ServerName, base.Cfg.Global.IsLocalServerName, keyRing,
 			)
 			if fedReq == nil {
 				return errResp