Fix some more inthttp

clientapi/routing/admin.go

@@ -110,7 +110,7 @@ func AdminResetPassword(req *http.Request, cfg *config.ClientAPI, device *userap
 			JSON: jsonerror.MissingArgument("Expecting user localpart."),
 		}
 	}
-	if l, s, err := gomatrixserverlib.SplitID('@', localpart); err == nil {
+	if l, s, err := cfg.Matrix.SplitLocalID('@', localpart); err == nil {
 		localpart, serverName = l, s
 	}
 	request := struct {

clientapi/routing/createroom.go

@@ -477,7 +477,7 @@ func createRoom(
 			SendAsServer: roomserverAPI.DoNotSendToOtherServers,
 		})
 	}
-	if err = roomserverAPI.SendInputRoomEvents(ctx, rsAPI, inputs, false); err != nil {
+	if err = roomserverAPI.SendInputRoomEvents(ctx, rsAPI, device.UserDomain(), inputs, false); err != nil {
 		util.GetLogger(ctx).WithError(err).Error("roomserverAPI.SendInputRoomEvents failed")
 		return jsonerror.InternalServerError()
 	}

clientapi/routing/directory.go

@@ -77,7 +77,7 @@ func DirectoryRoom(
 		// If we don't know it locally, do a federation query.
 		// But don't send the query to ourselves.
 		if !cfg.Matrix.IsLocalServerName(domain) {
-			fedRes, fedErr := federation.LookupRoomAlias(req.Context(), domain, roomAlias)
+			fedRes, fedErr := federation.LookupRoomAlias(req.Context(), cfg.Matrix.ServerName, domain, roomAlias)
 			if fedErr != nil {
 				// TODO: Return 502 if the remote server errored.
 				// TODO: Return 504 if the remote server timed out.

clientapi/routing/directory_public.go

@@ -74,7 +74,7 @@ func GetPostPublicRooms(
 	serverName := gomatrixserverlib.ServerName(request.Server)
 	if serverName != "" && !cfg.Matrix.IsLocalServerName(serverName) {
 		res, err := federation.GetPublicRoomsFiltered(
-			req.Context(), serverName,
+			req.Context(), cfg.Matrix.ServerName, serverName,
 			int(request.Limit), request.Since,
 			request.Filter.SearchTerms, false,
 			"",

clientapi/routing/membership.go

@@ -110,6 +110,7 @@ func sendMembership(ctx context.Context, profileAPI userapi.ClientUserAPI, devic
 		ctx, rsAPI,
 		roomserverAPI.KindNew,
 		[]*gomatrixserverlib.HeaderedEvent{event.Event.Headered(roomVer)},
+		device.UserDomain(),
 		serverName,
 		serverName,
 		nil,
@@ -322,7 +323,12 @@ func buildMembershipEvent(
 		return nil, err
 	}
 
-	return eventutil.QueryAndBuildEvent(ctx, &builder, cfg.Matrix, evTime, rsAPI, nil)
+	identity, err := cfg.Matrix.SigningIdentityFor(device.UserDomain())
+	if err != nil {
+		return nil, err
+	}
+
+	return eventutil.QueryAndBuildEvent(ctx, &builder, cfg.Matrix, identity, evTime, rsAPI, nil)
 }
 
 // loadProfile lookups the profile of a given user from the database and returns

clientapi/routing/profile.go

@@ -284,7 +284,7 @@ func updateProfile(
 	}
 
 	events, err := buildMembershipEvents(
-		ctx, res.RoomIDs, *profile, userID, cfg, evTime, rsAPI,
+		ctx, device, res.RoomIDs, *profile, userID, cfg, evTime, rsAPI,
 	)
 	switch e := err.(type) {
 	case nil:
@@ -298,7 +298,7 @@ func updateProfile(
 		return jsonerror.InternalServerError(), e
 	}
 
-	if err := api.SendEvents(ctx, rsAPI, api.KindNew, events, domain, domain, nil, true); err != nil {
+	if err := api.SendEvents(ctx, rsAPI, api.KindNew, events, device.UserDomain(), domain, domain, nil, true); err != nil {
 		util.GetLogger(ctx).WithError(err).Error("SendEvents failed")
 		return jsonerror.InternalServerError(), err
 	}
@@ -321,7 +321,7 @@ func getProfile(
 	}
 
 	if !cfg.Matrix.IsLocalServerName(domain) {
-		profile, fedErr := federation.LookupProfile(ctx, domain, userID, "")
+		profile, fedErr := federation.LookupProfile(ctx, cfg.Matrix.ServerName, domain, userID, "")
 		if fedErr != nil {
 			if x, ok := fedErr.(gomatrix.HTTPError); ok {
 				if x.Code == http.StatusNotFound {
@@ -349,6 +349,7 @@ func getProfile(
 
 func buildMembershipEvents(
 	ctx context.Context,
+	device *userapi.Device,
 	roomIDs []string,
 	newProfile authtypes.Profile, userID string, cfg *config.ClientAPI,
 	evTime time.Time, rsAPI api.ClientRoomserverAPI,
@@ -380,7 +381,12 @@ func buildMembershipEvents(
 			return nil, err
 		}
 
-		event, err := eventutil.QueryAndBuildEvent(ctx, &builder, cfg.Matrix, evTime, rsAPI, nil)
+		identity, err := cfg.Matrix.SigningIdentityFor(device.UserDomain())
+		if err != nil {
+			return nil, err
+		}
+
+		event, err := eventutil.QueryAndBuildEvent(ctx, &builder, cfg.Matrix, identity, evTime, rsAPI, nil)
 		if err != nil {
 			return nil, err
 		}

clientapi/routing/redaction.go

@@ -123,8 +123,13 @@ func SendRedaction(
 		return jsonerror.InternalServerError()
 	}
 
+	identity, err := cfg.Matrix.SigningIdentityFor(device.UserDomain())
+	if err != nil {
+		return jsonerror.InternalServerError()
+	}
+
 	var queryRes roomserverAPI.QueryLatestEventsAndStateResponse
-	e, err := eventutil.QueryAndBuildEvent(req.Context(), &builder, cfg.Matrix, time.Now(), rsAPI, &queryRes)
+	e, err := eventutil.QueryAndBuildEvent(req.Context(), &builder, cfg.Matrix, identity, time.Now(), rsAPI, &queryRes)
 	if err == eventutil.ErrRoomNoExists {
 		return util.JSONResponse{
 			Code: http.StatusNotFound,
@@ -132,7 +137,7 @@ func SendRedaction(
 		}
 	}
 	domain := device.UserDomain()
-	if err = roomserverAPI.SendEvents(context.Background(), rsAPI, roomserverAPI.KindNew, []*gomatrixserverlib.HeaderedEvent{e}, domain, domain, nil, false); err != nil {
+	if err = roomserverAPI.SendEvents(context.Background(), rsAPI, roomserverAPI.KindNew, []*gomatrixserverlib.HeaderedEvent{e}, device.UserDomain(), domain, domain, nil, false); err != nil {
 		util.GetLogger(req.Context()).WithError(err).Errorf("failed to SendEvents")
 		return jsonerror.InternalServerError()
 	}

clientapi/routing/register.go

@@ -211,9 +211,10 @@ var (
 // previous parameters with the ones supplied. This mean you cannot "build up" request params.
 type registerRequest struct {
 	// registration parameters
-	Password string `json:"password"`
-	Username string `json:"username"`
-	Admin    bool   `json:"admin"`
+	Password   string                       `json:"password"`
+	Username   string                       `json:"username"`
+	ServerName gomatrixserverlib.ServerName `json:"-"`
+	Admin      bool                         `json:"admin"`
 	// user-interactive auth params
 	Auth authDict `json:"auth"`
 
@@ -570,11 +571,14 @@ func Register(
 				JSON: response,
 			}
 		}
-
 	}
 	if resErr := httputil.UnmarshalJSON(reqBody, &r); resErr != nil {
 		return *resErr
 	}
+	r.ServerName = cfg.Matrix.ServerName
+	if l, d, err := cfg.Matrix.SplitLocalID('@', r.Username); err == nil {
+		r.Username, r.ServerName = l, d
+	}
 	if req.URL.Query().Get("kind") == "guest" {
 		return handleGuestRegistration(req, r, cfg, userAPI)
 	}
@@ -589,7 +593,7 @@ func Register(
 	// Auto generate a numeric username if r.Username is empty
 	if r.Username == "" {
 		nreq := &userapi.QueryNumericLocalpartRequest{
-			ServerName: cfg.Matrix.ServerName, // TODO: might not be right
+			ServerName: r.ServerName,
 		}
 		nres := &userapi.QueryNumericLocalpartResponse{}
 		if err := userAPI.QueryNumericLocalpart(req.Context(), nreq, nres); err != nil {
@@ -609,7 +613,7 @@ func Register(
 	case r.Type == authtypes.LoginTypeApplicationService && accessTokenErr == nil:
 		// Spec-compliant case (the access_token is specified and the login type
 		// is correctly set, so it's an appservice registration)
-		if resErr := validateApplicationServiceUsername(r.Username, cfg.Matrix.ServerName); resErr != nil {
+		if resErr := validateApplicationServiceUsername(r.Username, r.ServerName); resErr != nil {
 			return *resErr
 		}
 	case accessTokenErr == nil:
@@ -622,7 +626,7 @@ func Register(
 	default:
 		// Spec-compliant case (neither the access_token nor the login type are
 		// specified, so it's a normal user registration)
-		if resErr := validateUsername(r.Username, cfg.Matrix.ServerName); resErr != nil {
+		if resErr := validateUsername(r.Username, r.ServerName); resErr != nil {
 			return *resErr
 		}
 	}
@@ -1023,13 +1027,27 @@ func RegisterAvailable(
 
 	// Squash username to all lowercase letters
 	username = strings.ToLower(username)
+	domain := cfg.Matrix.ServerName
+	if u, l, err := cfg.Matrix.SplitLocalID('@', username); err == nil {
+		username, domain = u, l
+	}
+	for _, v := range cfg.Matrix.VirtualHosts {
+		if v.ServerName == domain && !v.AllowRegistration {
+			return util.JSONResponse{
+				Code: http.StatusForbidden,
+				JSON: jsonerror.Forbidden(
+					fmt.Sprintf("Registration is not allowed on %q", string(v.ServerName)),
+				),
+			}
+		}
+	}
 
-	if err := validateUsername(username, cfg.Matrix.ServerName); err != nil {
+	if err := validateUsername(username, domain); err != nil {
 		return *err
 	}
 
 	// Check if this username is reserved by an application service
-	userID := userutil.MakeUserID(username, cfg.Matrix.ServerName)
+	userID := userutil.MakeUserID(username, domain)
 	for _, appservice := range cfg.Derived.ApplicationServices {
 		if appservice.OwnsNamespaceCoveringUserId(userID) {
 			return util.JSONResponse{
@@ -1041,7 +1059,8 @@ func RegisterAvailable(
 
 	res := &userapi.QueryAccountAvailabilityResponse{}
 	err := registerAPI.QueryAccountAvailability(req.Context(), &userapi.QueryAccountAvailabilityRequest{
-		Localpart: username,
+		Localpart:  username,
+		ServerName: domain,
 	}, res)
 	if err != nil {
 		return util.JSONResponse{

clientapi/routing/sendevent.go

@@ -186,6 +186,7 @@ func SendEvent(
 		[]*gomatrixserverlib.HeaderedEvent{
 			e.Headered(verRes.RoomVersion),
 		},
+		device.UserDomain(),
 		domain,
 		domain,
 		txnAndSessionID,
@@ -275,8 +276,14 @@ func generateSendEvent(
 		return nil, &resErr
 	}
 
+	identity, err := cfg.Matrix.SigningIdentityFor(device.UserDomain())
+	if err != nil {
+		resErr := jsonerror.InternalServerError()
+		return nil, &resErr
+	}
+
 	var queryRes api.QueryLatestEventsAndStateResponse
-	e, err := eventutil.QueryAndBuildEvent(ctx, &builder, cfg.Matrix, evTime, rsAPI, &queryRes)
+	e, err := eventutil.QueryAndBuildEvent(ctx, &builder, cfg.Matrix, identity, evTime, rsAPI, &queryRes)
 	if err == eventutil.ErrRoomNoExists {
 		return nil, &util.JSONResponse{
 			Code: http.StatusNotFound,

clientapi/routing/server_notices.go

@@ -231,6 +231,7 @@ func SendServerNotice(
 		[]*gomatrixserverlib.HeaderedEvent{
 			e.Headered(roomVersion),
 		},
+		device.UserDomain(),
 		cfgClient.Matrix.ServerName,
 		cfgClient.Matrix.ServerName,
 		txnAndSessionID,

clientapi/routing/userdirectory.go

@@ -106,7 +106,7 @@ knownUsersLoop:
 				continue
 			}
 			// TODO: We should probably cache/store this
-			fedProfile, fedErr := federation.LookupProfile(ctx, serverName, userID, "")
+			fedProfile, fedErr := federation.LookupProfile(ctx, localServerName, serverName, userID, "")
 			if fedErr != nil {
 				if x, ok := fedErr.(gomatrix.HTTPError); ok {
 					if x.Code == http.StatusNotFound {

clientapi/threepid/invites.go

@@ -359,8 +359,13 @@ func emit3PIDInviteEvent(
 		return err
 	}
 
+	identity, err := cfg.Matrix.SigningIdentityFor(device.UserDomain())
+	if err != nil {
+		return err
+	}
+
 	queryRes := api.QueryLatestEventsAndStateResponse{}
-	event, err := eventutil.QueryAndBuildEvent(ctx, builder, cfg.Matrix, evTime, rsAPI, &queryRes)
+	event, err := eventutil.QueryAndBuildEvent(ctx, builder, cfg.Matrix, identity, evTime, rsAPI, &queryRes)
 	if err != nil {
 		return err
 	}
@@ -371,6 +376,7 @@ func emit3PIDInviteEvent(
 		[]*gomatrixserverlib.HeaderedEvent{
 			event.Headered(queryRes.RoomVersion),
 		},
+		device.UserDomain(),
 		cfg.Matrix.ServerName,
 		cfg.Matrix.ServerName,
 		nil,

cmd/dendrite-demo-pinecone/conn/client.go

@@ -101,9 +101,7 @@ func CreateFederationClient(
 	base *base.BaseDendrite, s *pineconeSessions.Sessions,
 ) *gomatrixserverlib.FederationClient {
 	return gomatrixserverlib.NewFederationClient(
-		base.Cfg.Global.ServerName,
-		base.Cfg.Global.KeyID,
-		base.Cfg.Global.PrivateKey,
+		base.Cfg.Global.SigningIdentities(),
 		gomatrixserverlib.WithTransport(createTransport(s)),
 	)
 }

cmd/dendrite-demo-pinecone/rooms/rooms.go

@@ -58,13 +58,17 @@ func (p *PineconeRoomProvider) Rooms() []gomatrixserverlib.PublicRoom {
 	for _, k := range p.r.Peers() {
 		list[gomatrixserverlib.ServerName(k.PublicKey)] = struct{}{}
 	}
-	return bulkFetchPublicRoomsFromServers(context.Background(), p.fedClient, list)
+	return bulkFetchPublicRoomsFromServers(
+		context.Background(), p.fedClient,
+		gomatrixserverlib.ServerName(p.r.PublicKey().String()), list,
+	)
 }
 
 // bulkFetchPublicRoomsFromServers fetches public rooms from the list of homeservers.
 // Returns a list of public rooms.
 func bulkFetchPublicRoomsFromServers(
 	ctx context.Context, fedClient *gomatrixserverlib.FederationClient,
+	origin gomatrixserverlib.ServerName,
 	homeservers map[gomatrixserverlib.ServerName]struct{},
 ) (publicRooms []gomatrixserverlib.PublicRoom) {
 	limit := 200
@@ -82,7 +86,7 @@ func bulkFetchPublicRoomsFromServers(
 		go func(homeserverDomain gomatrixserverlib.ServerName) {
 			defer wg.Done()
 			util.GetLogger(reqctx).WithField("hs", homeserverDomain).Info("Querying HS for public rooms")
-			fres, err := fedClient.GetPublicRooms(reqctx, homeserverDomain, int(limit), "", false, "")
+			fres, err := fedClient.GetPublicRooms(reqctx, origin, homeserverDomain, int(limit), "", false, "")
 			if err != nil {
 				util.GetLogger(reqctx).WithError(err).WithField("hs", homeserverDomain).Warn(
 					"bulkFetchPublicRoomsFromServers: failed to query hs",

cmd/dendrite-demo-yggdrasil/yggconn/client.go

@@ -55,8 +55,7 @@ func (n *Node) CreateFederationClient(
 		},
 	)
 	return gomatrixserverlib.NewFederationClient(
-		base.Cfg.Global.ServerName, base.Cfg.Global.KeyID,
-		base.Cfg.Global.PrivateKey,
+		base.Cfg.Global.SigningIdentities(),
 		gomatrixserverlib.WithTransport(tr),
 	)
 }

cmd/dendrite-demo-yggdrasil/yggrooms/yggrooms.go

@@ -43,13 +43,18 @@ func NewYggdrasilRoomProvider(
 }
 
 func (p *YggdrasilRoomProvider) Rooms() []gomatrixserverlib.PublicRoom {
-	return bulkFetchPublicRoomsFromServers(context.Background(), p.fedClient, p.node.KnownNodes())
+	return bulkFetchPublicRoomsFromServers(
+		context.Background(), p.fedClient,
+		gomatrixserverlib.ServerName(p.node.DerivedServerName()),
+		p.node.KnownNodes(),
+	)
 }
 
 // bulkFetchPublicRoomsFromServers fetches public rooms from the list of homeservers.
 // Returns a list of public rooms.
 func bulkFetchPublicRoomsFromServers(
 	ctx context.Context, fedClient *gomatrixserverlib.FederationClient,
+	origin gomatrixserverlib.ServerName,
 	homeservers []gomatrixserverlib.ServerName,
 ) (publicRooms []gomatrixserverlib.PublicRoom) {
 	limit := 200
@@ -66,7 +71,7 @@ func bulkFetchPublicRoomsFromServers(
 		go func(homeserverDomain gomatrixserverlib.ServerName) {
 			defer wg.Done()
 			util.GetLogger(ctx).WithField("hs", homeserverDomain).Info("Querying HS for public rooms")
-			fres, err := fedClient.GetPublicRooms(ctx, homeserverDomain, int(limit), "", false, "")
+			fres, err := fedClient.GetPublicRooms(ctx, origin, homeserverDomain, int(limit), "", false, "")
 			if err != nil {
 				util.GetLogger(ctx).WithError(err).WithField("hs", homeserverDomain).Warn(
 					"bulkFetchPublicRoomsFromServers: failed to query hs",

cmd/furl/main.go

@@ -48,10 +48,15 @@ func main() {
 		panic("unexpected key block")
 	}
 
+	serverName := gomatrixserverlib.ServerName(*requestFrom)
 	client := gomatrixserverlib.NewFederationClient(
-		gomatrixserverlib.ServerName(*requestFrom),
-		gomatrixserverlib.KeyID(keyBlock.Headers["Key-ID"]),
-		privateKey,
+		[]*gomatrixserverlib.SigningIdentity{
+			{
+				ServerName: serverName,
+				KeyID:      gomatrixserverlib.KeyID(keyBlock.Headers["Key-ID"]),
+				PrivateKey: privateKey,
+			},
+		},
 	)
 
 	u, err := url.Parse(flag.Arg(0))
@@ -79,6 +84,7 @@ func main() {
 
 	req := gomatrixserverlib.NewFederationRequest(
 		method,
+		serverName,
 		gomatrixserverlib.ServerName(u.Host),
 		u.RequestURI(),
 	)

federationapi/api/api.go

@@ -21,8 +21,8 @@ type FederationInternalAPI interface {
 
 	QueryServerKeys(ctx context.Context, request *QueryServerKeysRequest, response *QueryServerKeysResponse) error
 	LookupServerKeys(ctx context.Context, s gomatrixserverlib.ServerName, keyRequests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp) ([]gomatrixserverlib.ServerKeys, error)
-	MSC2836EventRelationships(ctx context.Context, dst gomatrixserverlib.ServerName, r gomatrixserverlib.MSC2836EventRelationshipsRequest, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.MSC2836EventRelationshipsResponse, err error)
-	MSC2946Spaces(ctx context.Context, dst gomatrixserverlib.ServerName, roomID string, suggestedOnly bool) (res gomatrixserverlib.MSC2946SpacesResponse, err error)
+	MSC2836EventRelationships(ctx context.Context, origin, dst gomatrixserverlib.ServerName, r gomatrixserverlib.MSC2836EventRelationshipsRequest, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.MSC2836EventRelationshipsResponse, err error)
+	MSC2946Spaces(ctx context.Context, origin, dst gomatrixserverlib.ServerName, roomID string, suggestedOnly bool) (res gomatrixserverlib.MSC2946SpacesResponse, err error)
 
 	// Broadcasts an EDU to all servers in rooms we are joined to. Used in the yggdrasil demos.
 	PerformBroadcastEDU(
@@ -60,18 +60,18 @@ type RoomserverFederationAPI interface {
 	// containing only the server names (without information for membership events).
 	// The response will include this server if they are joined to the room.
 	QueryJoinedHostServerNamesInRoom(ctx context.Context, request *QueryJoinedHostServerNamesInRoomRequest, response *QueryJoinedHostServerNamesInRoomResponse) error
-	GetEventAuth(ctx context.Context, s gomatrixserverlib.ServerName, roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string) (res gomatrixserverlib.RespEventAuth, err error)
-	GetEvent(ctx context.Context, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error)
-	LookupMissingEvents(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMissingEvents, err error)
+	GetEventAuth(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string) (res gomatrixserverlib.RespEventAuth, err error)
+	GetEvent(ctx context.Context, origin, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error)
+	LookupMissingEvents(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMissingEvents, err error)
 }
 
 // KeyserverFederationAPI is a subset of gomatrixserverlib.FederationClient functions which the keyserver
 // implements as proxy calls, with built-in backoff/retries/etc. Errors returned from functions in
 // this interface are of type FederationClientError
 type KeyserverFederationAPI interface {
-	GetUserDevices(ctx context.Context, s gomatrixserverlib.ServerName, userID string) (res gomatrixserverlib.RespUserDevices, err error)
-	ClaimKeys(ctx context.Context, s gomatrixserverlib.ServerName, oneTimeKeys map[string]map[string]string) (res gomatrixserverlib.RespClaimKeys, err error)
-	QueryKeys(ctx context.Context, s gomatrixserverlib.ServerName, keys map[string][]string) (res gomatrixserverlib.RespQueryKeys, err error)
+	GetUserDevices(ctx context.Context, origin, s gomatrixserverlib.ServerName, userID string) (res gomatrixserverlib.RespUserDevices, err error)
+	ClaimKeys(ctx context.Context, origin, s gomatrixserverlib.ServerName, oneTimeKeys map[string]map[string]string) (res gomatrixserverlib.RespClaimKeys, err error)
+	QueryKeys(ctx context.Context, origin, s gomatrixserverlib.ServerName, keys map[string][]string) (res gomatrixserverlib.RespQueryKeys, err error)
 }
 
 // an interface for gmsl.FederationClient - contains functions called by federationapi only.
@@ -80,28 +80,28 @@ type FederationClient interface {
 	SendTransaction(ctx context.Context, t gomatrixserverlib.Transaction) (res gomatrixserverlib.RespSend, err error)
 
 	// Perform operations
-	LookupRoomAlias(ctx context.Context, s gomatrixserverlib.ServerName, roomAlias string) (res gomatrixserverlib.RespDirectory, err error)
-	Peek(ctx context.Context, s gomatrixserverlib.ServerName, roomID, peekID string, roomVersions []gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespPeek, err error)
-	MakeJoin(ctx context.Context, s gomatrixserverlib.ServerName, roomID, userID string, roomVersions []gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMakeJoin, err error)
-	SendJoin(ctx context.Context, s gomatrixserverlib.ServerName, event *gomatrixserverlib.Event) (res gomatrixserverlib.RespSendJoin, err error)
-	MakeLeave(ctx context.Context, s gomatrixserverlib.ServerName, roomID, userID string) (res gomatrixserverlib.RespMakeLeave, err error)
-	SendLeave(ctx context.Context, s gomatrixserverlib.ServerName, event *gomatrixserverlib.Event) (err error)
-	SendInviteV2(ctx context.Context, s gomatrixserverlib.ServerName, request gomatrixserverlib.InviteV2Request) (res gomatrixserverlib.RespInviteV2, err error)
+	LookupRoomAlias(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomAlias string) (res gomatrixserverlib.RespDirectory, err error)
+	Peek(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID, peekID string, roomVersions []gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespPeek, err error)
+	MakeJoin(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID, userID string, roomVersions []gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMakeJoin, err error)
+	SendJoin(ctx context.Context, origin, s gomatrixserverlib.ServerName, event *gomatrixserverlib.Event) (res gomatrixserverlib.RespSendJoin, err error)
+	MakeLeave(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID, userID string) (res gomatrixserverlib.RespMakeLeave, err error)
+	SendLeave(ctx context.Context, origin, s gomatrixserverlib.ServerName, event *gomatrixserverlib.Event) (err error)
+	SendInviteV2(ctx context.Context, origin, s gomatrixserverlib.ServerName, request gomatrixserverlib.InviteV2Request) (res gomatrixserverlib.RespInviteV2, err error)
 
-	GetEvent(ctx context.Context, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error)
+	GetEvent(ctx context.Context, origin, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error)
 
-	GetEventAuth(ctx context.Context, s gomatrixserverlib.ServerName, roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string) (res gomatrixserverlib.RespEventAuth, err error)
-	GetUserDevices(ctx context.Context, s gomatrixserverlib.ServerName, userID string) (gomatrixserverlib.RespUserDevices, error)
-	ClaimKeys(ctx context.Context, s gomatrixserverlib.ServerName, oneTimeKeys map[string]map[string]string) (gomatrixserverlib.RespClaimKeys, error)
-	QueryKeys(ctx context.Context, s gomatrixserverlib.ServerName, keys map[string][]string) (gomatrixserverlib.RespQueryKeys, error)
-	Backfill(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, limit int, eventIDs []string) (res gomatrixserverlib.Transaction, err error)
-	MSC2836EventRelationships(ctx context.Context, dst gomatrixserverlib.ServerName, r gomatrixserverlib.MSC2836EventRelationshipsRequest, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.MSC2836EventRelationshipsResponse, err error)
-	MSC2946Spaces(ctx context.Context, dst gomatrixserverlib.ServerName, roomID string, suggestedOnly bool) (res gomatrixserverlib.MSC2946SpacesResponse, err error)
+	GetEventAuth(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string) (res gomatrixserverlib.RespEventAuth, err error)
+	GetUserDevices(ctx context.Context, origin, s gomatrixserverlib.ServerName, userID string) (gomatrixserverlib.RespUserDevices, error)
+	ClaimKeys(ctx context.Context, origin, s gomatrixserverlib.ServerName, oneTimeKeys map[string]map[string]string) (gomatrixserverlib.RespClaimKeys, error)
+	QueryKeys(ctx context.Context, origin, s gomatrixserverlib.ServerName, keys map[string][]string) (gomatrixserverlib.RespQueryKeys, error)
+	Backfill(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, limit int, eventIDs []string) (res gomatrixserverlib.Transaction, err error)
+	MSC2836EventRelationships(ctx context.Context, origin, dst gomatrixserverlib.ServerName, r gomatrixserverlib.MSC2836EventRelationshipsRequest, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.MSC2836EventRelationshipsResponse, err error)
+	MSC2946Spaces(ctx context.Context, origin, dst gomatrixserverlib.ServerName, roomID string, suggestedOnly bool) (res gomatrixserverlib.MSC2946SpacesResponse, err error)
 
-	ExchangeThirdPartyInvite(ctx context.Context, s gomatrixserverlib.ServerName, builder gomatrixserverlib.EventBuilder) (err error)
-	LookupState(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, eventID string, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespState, err error)
-	LookupStateIDs(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, eventID string) (res gomatrixserverlib.RespStateIDs, err error)
-	LookupMissingEvents(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMissingEvents, err error)
+	ExchangeThirdPartyInvite(ctx context.Context, origin, s gomatrixserverlib.ServerName, builder gomatrixserverlib.EventBuilder) (err error)
+	LookupState(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, eventID string, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespState, err error)
+	LookupStateIDs(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, eventID string) (res gomatrixserverlib.RespStateIDs, err error)
+	LookupMissingEvents(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents, roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMissingEvents, err error)
 }
 
 // FederationClientError is returned from FederationClient methods in the event of a problem.

federationapi/federationapi.go

@@ -120,17 +120,7 @@ func NewInternalAPI(
 
 	js, nats := base.NATS.Prepare(base.ProcessContext, &cfg.Matrix.JetStream)
 
-	signingInfo := map[gomatrixserverlib.ServerName]*queue.SigningInfo{}
-	for _, serverName := range append(
-		[]gomatrixserverlib.ServerName{base.Cfg.Global.ServerName},
-		base.Cfg.Global.SecondaryServerNames...,
-	) {
-		signingInfo[serverName] = &queue.SigningInfo{
-			KeyID:      cfg.Matrix.KeyID,
-			PrivateKey: cfg.Matrix.PrivateKey,
-			ServerName: serverName,
-		}
-	}
+	signingInfo := base.Cfg.Global.SigningIdentities()
 
 	queues := queue.NewOutgoingQueues(
 		federationDB, base.ProcessContext,

federationapi/federationapi_keys_test.go

@@ -104,7 +104,7 @@ func TestMain(m *testing.M) {
 
 			// Create the federation client.
 			s.fedclient = gomatrixserverlib.NewFederationClient(
-				s.config.Matrix.ServerName, serverKeyID, testPriv,
+				s.config.Matrix.SigningIdentities(),
 				gomatrixserverlib.WithTransport(transport),
 			)
 

federationapi/federationapi_test.go

@@ -103,7 +103,7 @@ func (f *fedClient) GetServerKeys(ctx context.Context, matrixServer gomatrixserv
 	return keys, nil
 }
 
-func (f *fedClient) MakeJoin(ctx context.Context, s gomatrixserverlib.ServerName, roomID, userID string, roomVersions []gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMakeJoin, err error) {
+func (f *fedClient) MakeJoin(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID, userID string, roomVersions []gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMakeJoin, err error) {
 	for _, r := range f.allowJoins {
 		if r.ID == roomID {
 			res.RoomVersion = r.Version
@@ -127,7 +127,7 @@ func (f *fedClient) MakeJoin(ctx context.Context, s gomatrixserverlib.ServerName
 	}
 	return
 }
-func (f *fedClient) SendJoin(ctx context.Context, s gomatrixserverlib.ServerName, event *gomatrixserverlib.Event) (res gomatrixserverlib.RespSendJoin, err error) {
+func (f *fedClient) SendJoin(ctx context.Context, origin, s gomatrixserverlib.ServerName, event *gomatrixserverlib.Event) (res gomatrixserverlib.RespSendJoin, err error) {
 	f.fedClientMutex.Lock()
 	defer f.fedClientMutex.Unlock()
 	for _, r := range f.allowJoins {
@@ -283,7 +283,7 @@ func TestRoomsV3URLEscapeDoNot404(t *testing.T) {
 	serverName := gomatrixserverlib.ServerName(strings.TrimPrefix(baseURL, "https://"))
 
 	fedCli := gomatrixserverlib.NewFederationClient(
-		serverName, cfg.Global.KeyID, cfg.Global.PrivateKey,
+		cfg.Global.SigningIdentities(),
 		gomatrixserverlib.WithSkipVerify(true),
 	)
 
@@ -326,7 +326,7 @@ func TestRoomsV3URLEscapeDoNot404(t *testing.T) {
 			t.Errorf("failed to create invite v2 request: %s", err)
 			continue
 		}
-		_, err = fedCli.SendInviteV2(context.Background(), serverName, invReq)
+		_, err = fedCli.SendInviteV2(context.Background(), cfg.Global.ServerName, serverName, invReq)
 		if err == nil {
 			t.Errorf("expected an error, got none")
 			continue

federationapi/internal/federationclient.go

@@ -11,13 +11,13 @@ import (
 // client.
 
 func (a *FederationInternalAPI) GetEventAuth(
-	ctx context.Context, s gomatrixserverlib.ServerName,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName,
 	roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string,
 ) (res gomatrixserverlib.RespEventAuth, err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.GetEventAuth(ctx, s, roomVersion, roomID, eventID)
+		return a.federation.GetEventAuth(ctx, origin, s, roomVersion, roomID, eventID)
 	})
 	if err != nil {
 		return gomatrixserverlib.RespEventAuth{}, err
@@ -26,12 +26,12 @@ func (a *FederationInternalAPI) GetEventAuth(
 }
 
 func (a *FederationInternalAPI) GetUserDevices(
-	ctx context.Context, s gomatrixserverlib.ServerName, userID string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, userID string,
 ) (gomatrixserverlib.RespUserDevices, error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.GetUserDevices(ctx, s, userID)
+		return a.federation.GetUserDevices(ctx, origin, s, userID)
 	})
 	if err != nil {
 		return gomatrixserverlib.RespUserDevices{}, err
@@ -40,12 +40,12 @@ func (a *FederationInternalAPI) GetUserDevices(
 }
 
 func (a *FederationInternalAPI) ClaimKeys(
-	ctx context.Context, s gomatrixserverlib.ServerName, oneTimeKeys map[string]map[string]string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, oneTimeKeys map[string]map[string]string,
 ) (gomatrixserverlib.RespClaimKeys, error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.ClaimKeys(ctx, s, oneTimeKeys)
+		return a.federation.ClaimKeys(ctx, origin, s, oneTimeKeys)
 	})
 	if err != nil {
 		return gomatrixserverlib.RespClaimKeys{}, err
@@ -54,10 +54,10 @@ func (a *FederationInternalAPI) ClaimKeys(
 }
 
 func (a *FederationInternalAPI) QueryKeys(
-	ctx context.Context, s gomatrixserverlib.ServerName, keys map[string][]string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, keys map[string][]string,
 ) (gomatrixserverlib.RespQueryKeys, error) {
 	ires, err := a.doRequestIfNotBackingOffOrBlacklisted(s, func() (interface{}, error) {
-		return a.federation.QueryKeys(ctx, s, keys)
+		return a.federation.QueryKeys(ctx, origin, s, keys)
 	})
 	if err != nil {
 		return gomatrixserverlib.RespQueryKeys{}, err
@@ -66,12 +66,12 @@ func (a *FederationInternalAPI) QueryKeys(
 }
 
 func (a *FederationInternalAPI) Backfill(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID string, limit int, eventIDs []string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, limit int, eventIDs []string,
 ) (res gomatrixserverlib.Transaction, err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.Backfill(ctx, s, roomID, limit, eventIDs)
+		return a.federation.Backfill(ctx, origin, s, roomID, limit, eventIDs)
 	})
 	if err != nil {
 		return gomatrixserverlib.Transaction{}, err
@@ -80,12 +80,12 @@ func (a *FederationInternalAPI) Backfill(
 }
 
 func (a *FederationInternalAPI) LookupState(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID, eventID string, roomVersion gomatrixserverlib.RoomVersion,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID, eventID string, roomVersion gomatrixserverlib.RoomVersion,
 ) (res gomatrixserverlib.RespState, err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.LookupState(ctx, s, roomID, eventID, roomVersion)
+		return a.federation.LookupState(ctx, origin, s, roomID, eventID, roomVersion)
 	})
 	if err != nil {
 		return gomatrixserverlib.RespState{}, err
@@ -94,12 +94,12 @@ func (a *FederationInternalAPI) LookupState(
 }
 
 func (a *FederationInternalAPI) LookupStateIDs(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID, eventID string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID, eventID string,
 ) (res gomatrixserverlib.RespStateIDs, err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.LookupStateIDs(ctx, s, roomID, eventID)
+		return a.federation.LookupStateIDs(ctx, origin, s, roomID, eventID)
 	})
 	if err != nil {
 		return gomatrixserverlib.RespStateIDs{}, err
@@ -108,13 +108,13 @@ func (a *FederationInternalAPI) LookupStateIDs(
 }
 
 func (a *FederationInternalAPI) LookupMissingEvents(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string,
 	missing gomatrixserverlib.MissingEvents, roomVersion gomatrixserverlib.RoomVersion,
 ) (res gomatrixserverlib.RespMissingEvents, err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.LookupMissingEvents(ctx, s, roomID, missing, roomVersion)
+		return a.federation.LookupMissingEvents(ctx, origin, s, roomID, missing, roomVersion)
 	})
 	if err != nil {
 		return gomatrixserverlib.RespMissingEvents{}, err
@@ -123,12 +123,12 @@ func (a *FederationInternalAPI) LookupMissingEvents(
 }
 
 func (a *FederationInternalAPI) GetEvent(
-	ctx context.Context, s gomatrixserverlib.ServerName, eventID string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, eventID string,
 ) (res gomatrixserverlib.Transaction, err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.GetEvent(ctx, s, eventID)
+		return a.federation.GetEvent(ctx, origin, s, eventID)
 	})
 	if err != nil {
 		return gomatrixserverlib.Transaction{}, err
@@ -151,13 +151,13 @@ func (a *FederationInternalAPI) LookupServerKeys(
 }
 
 func (a *FederationInternalAPI) MSC2836EventRelationships(
-	ctx context.Context, s gomatrixserverlib.ServerName, r gomatrixserverlib.MSC2836EventRelationshipsRequest,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, r gomatrixserverlib.MSC2836EventRelationshipsRequest,
 	roomVersion gomatrixserverlib.RoomVersion,
 ) (res gomatrixserverlib.MSC2836EventRelationshipsResponse, err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Minute)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.MSC2836EventRelationships(ctx, s, r, roomVersion)
+		return a.federation.MSC2836EventRelationships(ctx, origin, s, r, roomVersion)
 	})
 	if err != nil {
 		return res, err
@@ -166,12 +166,12 @@ func (a *FederationInternalAPI) MSC2836EventRelationships(
 }
 
 func (a *FederationInternalAPI) MSC2946Spaces(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID string, suggestedOnly bool,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, suggestedOnly bool,
 ) (res gomatrixserverlib.MSC2946SpacesResponse, err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Minute)
 	defer cancel()
 	ires, err := a.doRequestIfNotBlacklisted(s, func() (interface{}, error) {
-		return a.federation.MSC2946Spaces(ctx, s, roomID, suggestedOnly)
+		return a.federation.MSC2946Spaces(ctx, origin, s, roomID, suggestedOnly)
 	})
 	if err != nil {
 		return res, err

federationapi/internal/perform.go

@@ -26,6 +26,7 @@ func (r *FederationInternalAPI) PerformDirectoryLookup(
 ) (err error) {
 	dir, err := r.federation.LookupRoomAlias(
 		ctx,
+		r.cfg.Matrix.ServerName,
 		request.ServerName,
 		request.RoomAlias,
 	)
@@ -143,10 +144,16 @@ func (r *FederationInternalAPI) performJoinUsingServer(
 	supportedVersions []gomatrixserverlib.RoomVersion,
 	unsigned map[string]interface{},
 ) error {
+	_, origin, err := r.cfg.Matrix.SplitLocalID('@', userID)
+	if err != nil {
+		return err
+	}
+
 	// Try to perform a make_join using the information supplied in the
 	// request.
 	respMakeJoin, err := r.federation.MakeJoin(
 		ctx,
+		origin,
 		serverName,
 		roomID,
 		userID,
@@ -192,7 +199,7 @@ func (r *FederationInternalAPI) performJoinUsingServer(
 	// Build the join event.
 	event, err := respMakeJoin.JoinEvent.Build(
 		time.Now(),
-		r.cfg.Matrix.ServerName,
+		origin,
 		r.cfg.Matrix.KeyID,
 		r.cfg.Matrix.PrivateKey,
 		respMakeJoin.RoomVersion,
@@ -204,6 +211,7 @@ func (r *FederationInternalAPI) performJoinUsingServer(
 	// Try to perform a send_join using the newly built event.
 	respSendJoin, err := r.federation.SendJoin(
 		context.Background(),
+		origin,
 		serverName,
 		event,
 	)
@@ -246,7 +254,7 @@ func (r *FederationInternalAPI) performJoinUsingServer(
 		respMakeJoin.RoomVersion,
 		r.keyRing,
 		event,
-		federatedAuthProvider(ctx, r.federation, r.keyRing, serverName),
+		federatedAuthProvider(ctx, r.federation, r.keyRing, origin, serverName),
 	)
 	if err != nil {
 		return fmt.Errorf("respSendJoin.Check: %w", err)
@@ -281,6 +289,7 @@ func (r *FederationInternalAPI) performJoinUsingServer(
 	if err = roomserverAPI.SendEventWithState(
 		context.Background(),
 		r.rsAPI,
+		origin,
 		roomserverAPI.KindNew,
 		respState,
 		event.Headered(respMakeJoin.RoomVersion),
@@ -427,6 +436,7 @@ func (r *FederationInternalAPI) performOutboundPeekUsingServer(
 	// request.
 	respPeek, err := r.federation.Peek(
 		ctx,
+		r.cfg.Matrix.ServerName,
 		serverName,
 		roomID,
 		peekID,
@@ -453,7 +463,7 @@ func (r *FederationInternalAPI) performOutboundPeekUsingServer(
 
 	// authenticate the state returned (check its auth events etc)
 	// the equivalent of CheckSendJoinResponse()
-	authEvents, _, err := respState.Check(ctx, respPeek.RoomVersion, r.keyRing, federatedAuthProvider(ctx, r.federation, r.keyRing, serverName))
+	authEvents, _, err := respState.Check(ctx, respPeek.RoomVersion, r.keyRing, federatedAuthProvider(ctx, r.federation, r.keyRing, r.cfg.Matrix.ServerName, serverName))
 	if err != nil {
 		return fmt.Errorf("error checking state returned from peeking: %w", err)
 	}
@@ -475,7 +485,7 @@ func (r *FederationInternalAPI) performOutboundPeekUsingServer(
 	// logrus.Warnf("got respPeek %#v", respPeek)
 	// Send the newly returned state to the roomserver to update our local view.
 	if err = roomserverAPI.SendEventWithState(
-		ctx, r.rsAPI,
+		ctx, r.rsAPI, r.cfg.Matrix.ServerName,
 		roomserverAPI.KindNew,
 		&respState,
 		respPeek.LatestEvent.Headered(respPeek.RoomVersion),
@@ -495,6 +505,11 @@ func (r *FederationInternalAPI) PerformLeave(
 	request *api.PerformLeaveRequest,
 	response *api.PerformLeaveResponse,
 ) (err error) {
+	_, origin, err := r.cfg.Matrix.SplitLocalID('@', request.UserID)
+	if err != nil {
+		return err
+	}
+
 	// Deduplicate the server names we were provided.
 	util.SortAndUnique(request.ServerNames)
 
@@ -505,6 +520,7 @@ func (r *FederationInternalAPI) PerformLeave(
 		// request.
 		respMakeLeave, err := r.federation.MakeLeave(
 			ctx,
+			origin,
 			serverName,
 			request.RoomID,
 			request.UserID,
@@ -546,7 +562,7 @@ func (r *FederationInternalAPI) PerformLeave(
 		// Build the leave event.
 		event, err := respMakeLeave.LeaveEvent.Build(
 			time.Now(),
-			r.cfg.Matrix.ServerName,
+			origin,
 			r.cfg.Matrix.KeyID,
 			r.cfg.Matrix.PrivateKey,
 			respMakeLeave.RoomVersion,
@@ -559,6 +575,7 @@ func (r *FederationInternalAPI) PerformLeave(
 		// Try to perform a send_leave using the newly built event.
 		err = r.federation.SendLeave(
 			ctx,
+			origin,
 			serverName,
 			event,
 		)
@@ -585,6 +602,11 @@ func (r *FederationInternalAPI) PerformInvite(
 	request *api.PerformInviteRequest,
 	response *api.PerformInviteResponse,
 ) (err error) {
+	_, origin, err := r.cfg.Matrix.SplitLocalID('@', request.Event.Sender())
+	if err != nil {
+		return err
+	}
+
 	if request.Event.StateKey() == nil {
 		return errors.New("invite must be a state event")
 	}
@@ -607,7 +629,7 @@ func (r *FederationInternalAPI) PerformInvite(
 		return fmt.Errorf("gomatrixserverlib.NewInviteV2Request: %w", err)
 	}
 
-	inviteRes, err := r.federation.SendInviteV2(ctx, destination, inviteReq)
+	inviteRes, err := r.federation.SendInviteV2(ctx, origin, destination, inviteReq)
 	if err != nil {
 		return fmt.Errorf("r.federation.SendInviteV2: failed to send invite: %w", err)
 	}
@@ -708,7 +730,7 @@ func setDefaultRoomVersionFromJoinEvent(joinEvent gomatrixserverlib.EventBuilder
 // FederatedAuthProvider is an auth chain provider which fetches events from the server provided
 func federatedAuthProvider(
 	ctx context.Context, federation api.FederationClient,
-	keyRing gomatrixserverlib.JSONVerifier, server gomatrixserverlib.ServerName,
+	keyRing gomatrixserverlib.JSONVerifier, origin, server gomatrixserverlib.ServerName,
 ) gomatrixserverlib.AuthChainProvider {
 	// A list of events that we have retried, if they were not included in
 	// the auth events supplied in the send_join.
@@ -738,7 +760,7 @@ func federatedAuthProvider(
 
 			// Try to retrieve the event from the server that sent us the send
 			// join response.
-			tx, txerr := federation.GetEvent(ctx, server, eventID)
+			tx, txerr := federation.GetEvent(ctx, origin, server, eventID)
 			if txerr != nil {
 				return nil, fmt.Errorf("missingAuth r.federation.GetEvent: %w", txerr)
 			}

federationapi/inthttp/client.go

@@ -152,16 +152,18 @@ func (h *httpFederationInternalAPI) PerformBroadcastEDU(
 
 type getUserDevices struct {
 	S      gomatrixserverlib.ServerName
+	Origin gomatrixserverlib.ServerName
 	UserID string
 }
 
 func (h *httpFederationInternalAPI) GetUserDevices(
-	ctx context.Context, s gomatrixserverlib.ServerName, userID string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, userID string,
 ) (gomatrixserverlib.RespUserDevices, error) {
 	return httputil.CallInternalProxyAPI[getUserDevices, gomatrixserverlib.RespUserDevices, *api.FederationClientError](
 		"GetUserDevices", h.federationAPIURL+FederationAPIGetUserDevicesPath, h.httpClient,
 		ctx, &getUserDevices{
 			S:      s,
+			Origin: origin,
 			UserID: userID,
 		},
 	)
@@ -169,52 +171,58 @@ func (h *httpFederationInternalAPI) GetUserDevices(
 
 type claimKeys struct {
 	S           gomatrixserverlib.ServerName
+	Origin      gomatrixserverlib.ServerName
 	OneTimeKeys map[string]map[string]string
 }
 
 func (h *httpFederationInternalAPI) ClaimKeys(
-	ctx context.Context, s gomatrixserverlib.ServerName, oneTimeKeys map[string]map[string]string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, oneTimeKeys map[string]map[string]string,
 ) (gomatrixserverlib.RespClaimKeys, error) {
 	return httputil.CallInternalProxyAPI[claimKeys, gomatrixserverlib.RespClaimKeys, *api.FederationClientError](
 		"ClaimKeys", h.federationAPIURL+FederationAPIClaimKeysPath, h.httpClient,
 		ctx, &claimKeys{
 			S:           s,
+			Origin:      origin,
 			OneTimeKeys: oneTimeKeys,
 		},
 	)
 }
 
 type queryKeys struct {
-	S    gomatrixserverlib.ServerName
-	Keys map[string][]string
+	S      gomatrixserverlib.ServerName
+	Origin gomatrixserverlib.ServerName
+	Keys   map[string][]string
 }
 
 func (h *httpFederationInternalAPI) QueryKeys(
-	ctx context.Context, s gomatrixserverlib.ServerName, keys map[string][]string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, keys map[string][]string,
 ) (gomatrixserverlib.RespQueryKeys, error) {
 	return httputil.CallInternalProxyAPI[queryKeys, gomatrixserverlib.RespQueryKeys, *api.FederationClientError](
 		"QueryKeys", h.federationAPIURL+FederationAPIQueryKeysPath, h.httpClient,
 		ctx, &queryKeys{
-			S:    s,
-			Keys: keys,
+			S:      s,
+			Origin: origin,
+			Keys:   keys,
 		},
 	)
 }
 
 type backfill struct {
 	S        gomatrixserverlib.ServerName
+	Origin   gomatrixserverlib.ServerName
 	RoomID   string
 	Limit    int
 	EventIDs []string
 }
 
 func (h *httpFederationInternalAPI) Backfill(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID string, limit int, eventIDs []string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, limit int, eventIDs []string,
 ) (gomatrixserverlib.Transaction, error) {
 	return httputil.CallInternalProxyAPI[backfill, gomatrixserverlib.Transaction, *api.FederationClientError](
 		"Backfill", h.federationAPIURL+FederationAPIBackfillPath, h.httpClient,
 		ctx, &backfill{
 			S:        s,
+			Origin:   origin,
 			RoomID:   roomID,
 			Limit:    limit,
 			EventIDs: eventIDs,
@@ -224,18 +232,20 @@ func (h *httpFederationInternalAPI) Backfill(
 
 type lookupState struct {
 	S           gomatrixserverlib.ServerName
+	Origin      gomatrixserverlib.ServerName
 	RoomID      string
 	EventID     string
 	RoomVersion gomatrixserverlib.RoomVersion
 }
 
 func (h *httpFederationInternalAPI) LookupState(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID, eventID string, roomVersion gomatrixserverlib.RoomVersion,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID, eventID string, roomVersion gomatrixserverlib.RoomVersion,
 ) (gomatrixserverlib.RespState, error) {
 	return httputil.CallInternalProxyAPI[lookupState, gomatrixserverlib.RespState, *api.FederationClientError](
 		"LookupState", h.federationAPIURL+FederationAPILookupStatePath, h.httpClient,
 		ctx, &lookupState{
 			S:           s,
+			Origin:      origin,
 			RoomID:      roomID,
 			EventID:     eventID,
 			RoomVersion: roomVersion,
@@ -245,17 +255,19 @@ func (h *httpFederationInternalAPI) LookupState(
 
 type lookupStateIDs struct {
 	S       gomatrixserverlib.ServerName
+	Origin  gomatrixserverlib.ServerName
 	RoomID  string
 	EventID string
 }
 
 func (h *httpFederationInternalAPI) LookupStateIDs(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID, eventID string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID, eventID string,
 ) (gomatrixserverlib.RespStateIDs, error) {
 	return httputil.CallInternalProxyAPI[lookupStateIDs, gomatrixserverlib.RespStateIDs, *api.FederationClientError](
 		"LookupStateIDs", h.federationAPIURL+FederationAPILookupStateIDsPath, h.httpClient,
 		ctx, &lookupStateIDs{
 			S:       s,
+			Origin:  origin,
 			RoomID:  roomID,
 			EventID: eventID,
 		},
@@ -264,19 +276,21 @@ func (h *httpFederationInternalAPI) LookupStateIDs(
 
 type lookupMissingEvents struct {
 	S           gomatrixserverlib.ServerName
+	Origin      gomatrixserverlib.ServerName
 	RoomID      string
 	Missing     gomatrixserverlib.MissingEvents
 	RoomVersion gomatrixserverlib.RoomVersion
 }
 
 func (h *httpFederationInternalAPI) LookupMissingEvents(
-	ctx context.Context, s gomatrixserverlib.ServerName, roomID string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string,
 	missing gomatrixserverlib.MissingEvents, roomVersion gomatrixserverlib.RoomVersion,
 ) (res gomatrixserverlib.RespMissingEvents, err error) {
 	return httputil.CallInternalProxyAPI[lookupMissingEvents, gomatrixserverlib.RespMissingEvents, *api.FederationClientError](
 		"LookupMissingEvents", h.federationAPIURL+FederationAPILookupMissingEventsPath, h.httpClient,
 		ctx, &lookupMissingEvents{
 			S:           s,
+			Origin:      origin,
 			RoomID:      roomID,
 			Missing:     missing,
 			RoomVersion: roomVersion,
@@ -286,16 +300,18 @@ func (h *httpFederationInternalAPI) LookupMissingEvents(
 
 type getEvent struct {
 	S       gomatrixserverlib.ServerName
+	Origin  gomatrixserverlib.ServerName
 	EventID string
 }
 
 func (h *httpFederationInternalAPI) GetEvent(
-	ctx context.Context, s gomatrixserverlib.ServerName, eventID string,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, eventID string,
 ) (gomatrixserverlib.Transaction, error) {
 	return httputil.CallInternalProxyAPI[getEvent, gomatrixserverlib.Transaction, *api.FederationClientError](
 		"GetEvent", h.federationAPIURL+FederationAPIGetEventPath, h.httpClient,
 		ctx, &getEvent{
 			S:       s,
+			Origin:  origin,
 			EventID: eventID,
 		},
 	)
@@ -303,19 +319,21 @@ func (h *httpFederationInternalAPI) GetEvent(
 
 type getEventAuth struct {
 	S           gomatrixserverlib.ServerName
+	Origin      gomatrixserverlib.ServerName
 	RoomVersion gomatrixserverlib.RoomVersion
 	RoomID      string
 	EventID     string
 }
 
 func (h *httpFederationInternalAPI) GetEventAuth(
-	ctx context.Context, s gomatrixserverlib.ServerName,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName,
 	roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string,
 ) (gomatrixserverlib.RespEventAuth, error) {
 	return httputil.CallInternalProxyAPI[getEventAuth, gomatrixserverlib.RespEventAuth, *api.FederationClientError](
 		"GetEventAuth", h.federationAPIURL+FederationAPIGetEventAuthPath, h.httpClient,
 		ctx, &getEventAuth{
 			S:           s,
+			Origin:      origin,
 			RoomVersion: roomVersion,
 			RoomID:      roomID,
 			EventID:     eventID,
@@ -351,18 +369,20 @@ func (h *httpFederationInternalAPI) LookupServerKeys(
 
 type eventRelationships struct {
 	S       gomatrixserverlib.ServerName
+	Origin  gomatrixserverlib.ServerName
 	Req     gomatrixserverlib.MSC2836EventRelationshipsRequest
 	RoomVer gomatrixserverlib.RoomVersion
 }
 
 func (h *httpFederationInternalAPI) MSC2836EventRelationships(
-	ctx context.Context, s gomatrixserverlib.ServerName, r gomatrixserverlib.MSC2836EventRelationshipsRequest,
+	ctx context.Context, origin, s gomatrixserverlib.ServerName, r gomatrixserverlib.MSC2836EventRelationshipsRequest,
 	roomVersion gomatrixserverlib.RoomVersion,
 ) (res gomatrixserverlib.MSC2836EventRelationshipsResponse, err error) {
 	return httputil.CallInternalProxyAPI[eventRelationships, gomatrixserverlib.MSC2836EventRelationshipsResponse, *api.FederationClientError](
 		"MSC2836EventRelationships", h.federationAPIURL+FederationAPIEventRelationshipsPath, h.httpClient,
 		ctx, &eventRelationships{
 			S:       s,
+			Origin:  origin,
 			Req:     r,
 			RoomVer: roomVersion,
 		},
@@ -371,17 +391,19 @@ func (h *httpFederationInternalAPI) MSC2836EventRelationships(
 
 type spacesReq struct {
 	S             gomatrixserverlib.ServerName
+	Origin        gomatrixserverlib.ServerName
 	SuggestedOnly bool
 	RoomID        string
 }
 
 func (h *httpFederationInternalAPI) MSC2946Spaces(
-	ctx context.Context, dst gomatrixserverlib.ServerName, roomID string, suggestedOnly bool,
+	ctx context.Context, origin, dst gomatrixserverlib.ServerName, roomID string, suggestedOnly bool,
 ) (res gomatrixserverlib.MSC2946SpacesResponse, err error) {
 	return httputil.CallInternalProxyAPI[spacesReq, gomatrixserverlib.MSC2946SpacesResponse, *api.FederationClientError](
 		"MSC2836EventRelationships", h.federationAPIURL+FederationAPISpacesSummaryPath, h.httpClient,
 		ctx, &spacesReq{
 			S:             dst,
+			Origin:        origin,
 			SuggestedOnly: suggestedOnly,
 			RoomID:        roomID,
 		},

federationapi/inthttp/server.go

@@ -59,7 +59,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPIGetUserDevices",
 			func(ctx context.Context, req *getUserDevices) (*gomatrixserverlib.RespUserDevices, error) {
-				res, err := intAPI.GetUserDevices(ctx, req.S, req.UserID)
+				res, err := intAPI.GetUserDevices(ctx, req.Origin, req.S, req.UserID)
 				return &res, federationClientError(err)
 			},
 		),
@@ -70,7 +70,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPIClaimKeys",
 			func(ctx context.Context, req *claimKeys) (*gomatrixserverlib.RespClaimKeys, error) {
-				res, err := intAPI.ClaimKeys(ctx, req.S, req.OneTimeKeys)
+				res, err := intAPI.ClaimKeys(ctx, req.Origin, req.S, req.OneTimeKeys)
 				return &res, federationClientError(err)
 			},
 		),
@@ -81,7 +81,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPIQueryKeys",
 			func(ctx context.Context, req *queryKeys) (*gomatrixserverlib.RespQueryKeys, error) {
-				res, err := intAPI.QueryKeys(ctx, req.S, req.Keys)
+				res, err := intAPI.QueryKeys(ctx, req.Origin, req.S, req.Keys)
 				return &res, federationClientError(err)
 			},
 		),
@@ -92,7 +92,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPIBackfill",
 			func(ctx context.Context, req *backfill) (*gomatrixserverlib.Transaction, error) {
-				res, err := intAPI.Backfill(ctx, req.S, req.RoomID, req.Limit, req.EventIDs)
+				res, err := intAPI.Backfill(ctx, req.Origin, req.S, req.RoomID, req.Limit, req.EventIDs)
 				return &res, federationClientError(err)
 			},
 		),
@@ -103,7 +103,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPILookupState",
 			func(ctx context.Context, req *lookupState) (*gomatrixserverlib.RespState, error) {
-				res, err := intAPI.LookupState(ctx, req.S, req.RoomID, req.EventID, req.RoomVersion)
+				res, err := intAPI.LookupState(ctx, req.Origin, req.S, req.RoomID, req.EventID, req.RoomVersion)
 				return &res, federationClientError(err)
 			},
 		),
@@ -114,7 +114,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPILookupStateIDs",
 			func(ctx context.Context, req *lookupStateIDs) (*gomatrixserverlib.RespStateIDs, error) {
-				res, err := intAPI.LookupStateIDs(ctx, req.S, req.RoomID, req.EventID)
+				res, err := intAPI.LookupStateIDs(ctx, req.Origin, req.S, req.RoomID, req.EventID)
 				return &res, federationClientError(err)
 			},
 		),
@@ -125,7 +125,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPILookupMissingEvents",
 			func(ctx context.Context, req *lookupMissingEvents) (*gomatrixserverlib.RespMissingEvents, error) {
-				res, err := intAPI.LookupMissingEvents(ctx, req.S, req.RoomID, req.Missing, req.RoomVersion)
+				res, err := intAPI.LookupMissingEvents(ctx, req.Origin, req.S, req.RoomID, req.Missing, req.RoomVersion)
 				return &res, federationClientError(err)
 			},
 		),
@@ -136,7 +136,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPIGetEvent",
 			func(ctx context.Context, req *getEvent) (*gomatrixserverlib.Transaction, error) {
-				res, err := intAPI.GetEvent(ctx, req.S, req.EventID)
+				res, err := intAPI.GetEvent(ctx, req.Origin, req.S, req.EventID)
 				return &res, federationClientError(err)
 			},
 		),
@@ -147,7 +147,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPIGetEventAuth",
 			func(ctx context.Context, req *getEventAuth) (*gomatrixserverlib.RespEventAuth, error) {
-				res, err := intAPI.GetEventAuth(ctx, req.S, req.RoomVersion, req.RoomID, req.EventID)
+				res, err := intAPI.GetEventAuth(ctx, req.Origin, req.S, req.RoomVersion, req.RoomID, req.EventID)
 				return &res, federationClientError(err)
 			},
 		),
@@ -174,7 +174,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPIMSC2836EventRelationships",
 			func(ctx context.Context, req *eventRelationships) (*gomatrixserverlib.MSC2836EventRelationshipsResponse, error) {
-				res, err := intAPI.MSC2836EventRelationships(ctx, req.S, req.Req, req.RoomVer)
+				res, err := intAPI.MSC2836EventRelationships(ctx, req.Origin, req.S, req.Req, req.RoomVer)
 				return &res, federationClientError(err)
 			},
 		),
@@ -185,7 +185,7 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 		httputil.MakeInternalProxyAPI(
 			"FederationAPIMSC2946SpacesSummary",
 			func(ctx context.Context, req *spacesReq) (*gomatrixserverlib.MSC2946SpacesResponse, error) {
-				res, err := intAPI.MSC2946Spaces(ctx, req.S, req.RoomID, req.SuggestedOnly)
+				res, err := intAPI.MSC2946Spaces(ctx, req.Origin, req.S, req.RoomID, req.SuggestedOnly)
 				return &res, federationClientError(err)
 			},
 		),

federationapi/queue/destinationqueue.go

@@ -50,7 +50,7 @@ type destinationQueue struct {
 	queues             *OutgoingQueues
 	db                 storage.Database
 	process            *process.ProcessContext
-	signing            map[gomatrixserverlib.ServerName]*SigningInfo
+	signing            map[gomatrixserverlib.ServerName]*gomatrixserverlib.SigningIdentity
 	rsAPI              api.FederationRoomserverAPI
 	client             fedapi.FederationClient         // federation client
 	origin             gomatrixserverlib.ServerName    // origin of requests

federationapi/queue/queue.go

@@ -15,7 +15,6 @@
 package queue
 
 import (
-	"crypto/ed25519"
 	"encoding/json"
 	"fmt"
 	"sync"
@@ -46,7 +45,7 @@ type OutgoingQueues struct {
 	origin      gomatrixserverlib.ServerName
 	client      fedapi.FederationClient
 	statistics  *statistics.Statistics
-	signing     map[gomatrixserverlib.ServerName]*SigningInfo
+	signing     map[gomatrixserverlib.ServerName]*gomatrixserverlib.SigningIdentity
 	queuesMutex sync.Mutex // protects the below
 	queues      map[gomatrixserverlib.ServerName]*destinationQueue
 }
@@ -91,7 +90,7 @@ func NewOutgoingQueues(
 	client fedapi.FederationClient,
 	rsAPI api.FederationRoomserverAPI,
 	statistics *statistics.Statistics,
-	signing map[gomatrixserverlib.ServerName]*SigningInfo,
+	signing []*gomatrixserverlib.SigningIdentity,
 ) *OutgoingQueues {
 	queues := &OutgoingQueues{
 		disabled:   disabled,
@@ -101,9 +100,12 @@ func NewOutgoingQueues(
 		origin:     origin,
 		client:     client,
 		statistics: statistics,
-		signing:    signing,
+		signing:    map[gomatrixserverlib.ServerName]*gomatrixserverlib.SigningIdentity{},
 		queues:     map[gomatrixserverlib.ServerName]*destinationQueue{},
 	}
+	for _, identity := range signing {
+		queues.signing[identity.ServerName] = identity
+	}
 	// Look up which servers we have pending items for and then rehydrate those queues.
 	if !disabled {
 		serverNames := map[gomatrixserverlib.ServerName]struct{}{}
@@ -135,14 +137,6 @@ func NewOutgoingQueues(
 	return queues
 }
 
-// TODO: Move this somewhere useful for other components as we often need to ferry these 3 variables
-// around together
-type SigningInfo struct {
-	ServerName gomatrixserverlib.ServerName
-	KeyID      gomatrixserverlib.KeyID
-	PrivateKey ed25519.PrivateKey
-}
-
 type queuedPDU struct {
 	receipt *shared.Receipt
 	pdu     *gomatrixserverlib.HeaderedEvent

federationapi/queue/queue_test.go

@@ -350,8 +350,8 @@ func testSetup(failuresUntilBlacklist uint32, shouldTxSucceed bool, t *testing.T
 	}
 	rs := &stubFederationRoomServerAPI{}
 	stats := statistics.NewStatistics(db, failuresUntilBlacklist)
-	signingInfo := map[gomatrixserverlib.ServerName]*SigningInfo{
-		"localhost": {
+	signingInfo := []*gomatrixserverlib.SigningIdentity{
+		{
 			KeyID:      "ed21019:auto",
 			PrivateKey: test.PrivateKeyA,
 			ServerName: "localhost",

federationapi/routing/backfill.go

@@ -82,7 +82,8 @@ func Backfill(
 		BackwardsExtremities: map[string][]string{
 			"": eIDs,
 		},
-		ServerName: request.Origin(),
+		ServerName:  request.Origin(),
+		VirtualHost: request.Destination(),
 	}
 	if req.Limit, err = strconv.Atoi(limit); err != nil {
 		util.GetLogger(httpReq.Context()).WithError(err).Error("strconv.Atoi failed")
@@ -123,7 +124,7 @@ func Backfill(
 	}
 
 	txn := gomatrixserverlib.Transaction{
-		Origin:         cfg.Matrix.ServerName,
+		Origin:         request.Destination(),
 		PDUs:           eventJSONs,
 		OriginServerTS: gomatrixserverlib.AsTimestamp(time.Now()),
 	}

federationapi/routing/invite.go

@@ -140,6 +140,21 @@ func processInvite(
 		}
 	}
 
+	if event.StateKey() == nil {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.BadJSON("The invite event has no state key"),
+		}
+	}
+
+	_, domain, err := cfg.Matrix.SplitLocalID('@', *event.StateKey())
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.InvalidArgumentValue(fmt.Sprintf("The user ID is invalid or domain %q does not belong to this server", domain)),
+		}
+	}
+
 	// Check that the event is signed by the server sending the request.
 	redacted, err := gomatrixserverlib.RedactEventJSON(event.JSON(), event.Version())
 	if err != nil {
@@ -175,7 +190,7 @@ func processInvite(
 
 	// Sign the event so that other servers will know that we have received the invite.
 	signedEvent := event.Sign(
-		string(cfg.Matrix.ServerName), cfg.Matrix.KeyID, cfg.Matrix.PrivateKey,
+		string(domain), cfg.Matrix.KeyID, cfg.Matrix.PrivateKey,
 	)
 
 	// Add the invite event to the roomserver.

federationapi/routing/join.go

@@ -131,10 +131,20 @@ func MakeJoin(
 		return jsonerror.InternalServerError()
 	}
 
+	identity, err := cfg.Matrix.SigningIdentityFor(request.Destination())
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusNotFound,
+			JSON: jsonerror.NotFound(
+				fmt.Sprintf("Server name %q does not exist", request.Destination()),
+			),
+		}
+	}
+
 	queryRes := api.QueryLatestEventsAndStateResponse{
 		RoomVersion: verRes.RoomVersion,
 	}
-	event, err := eventutil.QueryAndBuildEvent(httpReq.Context(), &builder, cfg.Matrix, time.Now(), rsAPI, &queryRes)
+	event, err := eventutil.QueryAndBuildEvent(httpReq.Context(), &builder, cfg.Matrix, identity, time.Now(), rsAPI, &queryRes)
 	if err == eventutil.ErrRoomNoExists {
 		return util.JSONResponse{
 			Code: http.StatusNotFound,

federationapi/routing/keys.go

@@ -16,7 +16,6 @@ package routing
 
 import (
 	"encoding/json"
-	"fmt"
 	"net/http"
 	"time"
 
@@ -136,38 +135,52 @@ func ClaimOneTimeKeys(
 // LocalKeys returns the local keys for the server.
 // See https://matrix.org/docs/spec/server_server/unstable.html#publishing-keys
 func LocalKeys(cfg *config.FederationAPI, serverName gomatrixserverlib.ServerName) util.JSONResponse {
-	keys, err := localKeys(cfg, serverName, time.Now().Add(cfg.Matrix.KeyValidityPeriod))
+	keys, err := localKeys(cfg, serverName)
 	if err != nil {
-		return util.ErrorResponse(err)
+		return util.MessageResponse(http.StatusNotFound, err.Error())
 	}
 	return util.JSONResponse{Code: http.StatusOK, JSON: keys}
 }
 
-func localKeys(cfg *config.FederationAPI, serverName gomatrixserverlib.ServerName, validUntil time.Time) (*gomatrixserverlib.ServerKeys, error) {
+func localKeys(cfg *config.FederationAPI, serverName gomatrixserverlib.ServerName) (*gomatrixserverlib.ServerKeys, error) {
 	var keys gomatrixserverlib.ServerKeys
-	if !cfg.Matrix.IsLocalServerName(serverName) {
-		return nil, fmt.Errorf("server name not known")
-	}
-
-	keys.ServerName = serverName
-	keys.ValidUntilTS = gomatrixserverlib.AsTimestamp(validUntil)
-
-	publicKey := cfg.Matrix.PrivateKey.Public().(ed25519.PublicKey)
-
-	keys.VerifyKeys = map[gomatrixserverlib.KeyID]gomatrixserverlib.VerifyKey{
-		cfg.Matrix.KeyID: {
-			Key: gomatrixserverlib.Base64Bytes(publicKey),
-		},
-	}
-
-	keys.OldVerifyKeys = map[gomatrixserverlib.KeyID]gomatrixserverlib.OldVerifyKey{}
-	for _, oldVerifyKey := range cfg.Matrix.OldVerifyKeys {
-		keys.OldVerifyKeys[oldVerifyKey.KeyID] = gomatrixserverlib.OldVerifyKey{
-			VerifyKey: gomatrixserverlib.VerifyKey{
-				Key: oldVerifyKey.PublicKey,
-			},
-			ExpiredTS: oldVerifyKey.ExpiredAt,
+	var virtualHost *config.VirtualHost
+	for _, v := range cfg.Matrix.VirtualHosts {
+		if v.ServerName != serverName {
+			continue
 		}
+		virtualHost = v
+	}
+
+	if virtualHost == nil {
+		publicKey := cfg.Matrix.PrivateKey.Public().(ed25519.PublicKey)
+		keys.ServerName = cfg.Matrix.ServerName
+		keys.ValidUntilTS = gomatrixserverlib.AsTimestamp(time.Now().Add(cfg.Matrix.KeyValidityPeriod))
+		keys.VerifyKeys = map[gomatrixserverlib.KeyID]gomatrixserverlib.VerifyKey{
+			cfg.Matrix.KeyID: {
+				Key: gomatrixserverlib.Base64Bytes(publicKey),
+			},
+		}
+		keys.OldVerifyKeys = map[gomatrixserverlib.KeyID]gomatrixserverlib.OldVerifyKey{}
+		for _, oldVerifyKey := range cfg.Matrix.OldVerifyKeys {
+			keys.OldVerifyKeys[oldVerifyKey.KeyID] = gomatrixserverlib.OldVerifyKey{
+				VerifyKey: gomatrixserverlib.VerifyKey{
+					Key: oldVerifyKey.PublicKey,
+				},
+				ExpiredTS: oldVerifyKey.ExpiredAt,
+			}
+		}
+	} else {
+		publicKey := virtualHost.PrivateKey.Public().(ed25519.PublicKey)
+		keys.ServerName = virtualHost.ServerName
+		keys.ValidUntilTS = gomatrixserverlib.AsTimestamp(time.Now().Add(virtualHost.KeyValidityPeriod))
+		keys.VerifyKeys = map[gomatrixserverlib.KeyID]gomatrixserverlib.VerifyKey{
+			virtualHost.KeyID: {
+				Key: gomatrixserverlib.Base64Bytes(publicKey),
+			},
+		}
+		// TODO: Virtual hosts probably want to be able to specify old signing
+		// keys too, just in case
 	}
 
 	toSign, err := json.Marshal(keys.ServerKeyFields)
@@ -213,7 +226,7 @@ func NotaryKeys(
 	for serverName, kidToCriteria := range req.ServerKeys {
 		var keyList []gomatrixserverlib.ServerKeys
 		if serverName == cfg.Matrix.ServerName {
-			if k, err := localKeys(cfg, serverName, time.Now().Add(cfg.Matrix.KeyValidityPeriod)); err == nil {
+			if k, err := localKeys(cfg, serverName); err == nil {
 				keyList = append(keyList, *k)
 			} else {
 				return util.ErrorResponse(err)

federationapi/routing/leave.go

@@ -13,6 +13,7 @@
 package routing
 
 import (
+	"fmt"
 	"net/http"
 	"time"
 
@@ -60,8 +61,18 @@ func MakeLeave(
 		return jsonerror.InternalServerError()
 	}
 
+	identity, err := cfg.Matrix.SigningIdentityFor(request.Destination())
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusNotFound,
+			JSON: jsonerror.NotFound(
+				fmt.Sprintf("Server name %q does not exist", request.Destination()),
+			),
+		}
+	}
+
 	var queryRes api.QueryLatestEventsAndStateResponse
-	event, err := eventutil.QueryAndBuildEvent(httpReq.Context(), &builder, cfg.Matrix, time.Now(), rsAPI, &queryRes)
+	event, err := eventutil.QueryAndBuildEvent(httpReq.Context(), &builder, cfg.Matrix, identity, time.Now(), rsAPI, &queryRes)
 	if err == eventutil.ErrRoomNoExists {
 		return util.JSONResponse{
 			Code: http.StatusNotFound,

federationapi/routing/profile.go

@@ -22,7 +22,6 @@ import (
 	"github.com/matrix-org/dendrite/internal/eventutil"
 	"github.com/matrix-org/dendrite/setup/config"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
-	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
 )
 
@@ -42,16 +41,9 @@ func GetProfile(
 		}
 	}
 
-	_, domain, err := gomatrixserverlib.SplitID('@', userID)
+	_, domain, err := cfg.Matrix.SplitLocalID('@', userID)
 	if err != nil {
 		util.GetLogger(httpReq.Context()).WithError(err).Error("gomatrixserverlib.SplitID failed")
-		return util.JSONResponse{
-			Code: http.StatusBadRequest,
-			JSON: jsonerror.MissingArgument(fmt.Sprintf("Format of user ID %q is invalid", userID)),
-		}
-	}
-
-	if domain != cfg.Matrix.ServerName {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
 			JSON: jsonerror.InvalidArgumentValue(fmt.Sprintf("Domain %q does not match this server", domain)),

federationapi/routing/query.go

@@ -83,7 +83,7 @@ func RoomAliasToID(
 			}
 		}
 	} else {
-		resp, err = federation.LookupRoomAlias(httpReq.Context(), domain, roomAlias)
+		resp, err = federation.LookupRoomAlias(httpReq.Context(), domain, cfg.Matrix.ServerName, roomAlias)
 		if err != nil {
 			switch x := err.(type) {
 			case gomatrix.HTTPError:

federationapi/routing/send.go

@@ -197,12 +197,12 @@ type txnReq struct {
 
 // A subset of FederationClient functionality that txn requires. Useful for testing.
 type txnFederationClient interface {
-	LookupState(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
+	LookupState(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
 		res gomatrixserverlib.RespState, err error,
 	)
-	LookupStateIDs(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, eventID string) (res gomatrixserverlib.RespStateIDs, err error)
-	GetEvent(ctx context.Context, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error)
-	LookupMissingEvents(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents,
+	LookupStateIDs(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, eventID string) (res gomatrixserverlib.RespStateIDs, err error)
+	GetEvent(ctx context.Context, origin, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error)
+	LookupMissingEvents(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents,
 		roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMissingEvents, err error)
 }
 
@@ -287,6 +287,7 @@ func (t *txnReq) processTransaction(ctx context.Context) (*gomatrixserverlib.Res
 			[]*gomatrixserverlib.HeaderedEvent{
 				event.Headered(roomVersion),
 			},
+			t.Destination,
 			t.Origin,
 			api.DoNotSendToOtherServers,
 			nil,

federationapi/routing/send_test.go

@@ -147,7 +147,7 @@ type txnFedClient struct {
 	getMissingEvents func(gomatrixserverlib.MissingEvents) (res gomatrixserverlib.RespMissingEvents, err error)
 }
 
-func (c *txnFedClient) LookupState(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
+func (c *txnFedClient) LookupState(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
 	res gomatrixserverlib.RespState, err error,
 ) {
 	fmt.Println("testFederationClient.LookupState", eventID)
@@ -159,7 +159,7 @@ func (c *txnFedClient) LookupState(ctx context.Context, s gomatrixserverlib.Serv
 	res = r
 	return
 }
-func (c *txnFedClient) LookupStateIDs(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, eventID string) (res gomatrixserverlib.RespStateIDs, err error) {
+func (c *txnFedClient) LookupStateIDs(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, eventID string) (res gomatrixserverlib.RespStateIDs, err error) {
 	fmt.Println("testFederationClient.LookupStateIDs", eventID)
 	r, ok := c.stateIDs[eventID]
 	if !ok {
@@ -169,7 +169,7 @@ func (c *txnFedClient) LookupStateIDs(ctx context.Context, s gomatrixserverlib.S
 	res = r
 	return
 }
-func (c *txnFedClient) GetEvent(ctx context.Context, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error) {
+func (c *txnFedClient) GetEvent(ctx context.Context, origin, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error) {
 	fmt.Println("testFederationClient.GetEvent", eventID)
 	r, ok := c.getEvent[eventID]
 	if !ok {
@@ -179,7 +179,7 @@ func (c *txnFedClient) GetEvent(ctx context.Context, s gomatrixserverlib.ServerN
 	res = r
 	return
 }
-func (c *txnFedClient) LookupMissingEvents(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents,
+func (c *txnFedClient) LookupMissingEvents(ctx context.Context, origin, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents,
 	roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMissingEvents, err error) {
 	return c.getMissingEvents(missing)
 }

federationapi/routing/threepid.go

@@ -90,7 +90,17 @@ func CreateInvitesFrom3PIDInvites(
 	}
 
 	// Send all the events
-	if err := api.SendEvents(req.Context(), rsAPI, api.KindNew, evs, "TODO", cfg.Matrix.ServerName, nil, false); err != nil {
+	if err := api.SendEvents(
+		req.Context(),
+		rsAPI,
+		api.KindNew,
+		evs,
+		cfg.Matrix.ServerName, // TODO: which virtual host?
+		"TODO",
+		cfg.Matrix.ServerName,
+		nil,
+		false,
+	); err != nil {
 		util.GetLogger(req.Context()).WithError(err).Error("SendEvents failed")
 		return jsonerror.InternalServerError()
 	}
@@ -126,6 +136,14 @@ func ExchangeThirdPartyInvite(
 		}
 	}
 
+	_, senderDomain, err := cfg.Matrix.SplitLocalID('@', builder.Sender)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.BadJSON("Invalid sender ID: " + err.Error()),
+		}
+	}
+
 	// Check that the state key is correct.
 	_, targetDomain, err := gomatrixserverlib.SplitID('@', *builder.StateKey)
 	if err != nil {
@@ -171,7 +189,7 @@ func ExchangeThirdPartyInvite(
 		util.GetLogger(httpReq.Context()).WithError(err).Error("failed to make invite v2 request")
 		return jsonerror.InternalServerError()
 	}
-	signedEvent, err := federation.SendInviteV2(httpReq.Context(), request.Origin(), inviteReq)
+	signedEvent, err := federation.SendInviteV2(httpReq.Context(), senderDomain, request.Origin(), inviteReq)
 	if err != nil {
 		util.GetLogger(httpReq.Context()).WithError(err).Error("federation.SendInvite failed")
 		return jsonerror.InternalServerError()
@@ -189,6 +207,7 @@ func ExchangeThirdPartyInvite(
 		[]*gomatrixserverlib.HeaderedEvent{
 			inviteEvent.Headered(verRes.RoomVersion),
 		},
+		request.Destination(),
 		request.Origin(),
 		cfg.Matrix.ServerName,
 		nil,
@@ -341,7 +360,7 @@ func buildMembershipEvent(
 // them responded with an error.
 func sendToRemoteServer(
 	ctx context.Context, inv invite,
-	federation federationAPI.FederationClient, _ *config.FederationAPI,
+	federation federationAPI.FederationClient, cfg *config.FederationAPI,
 	builder gomatrixserverlib.EventBuilder,
 ) (err error) {
 	remoteServers := make([]gomatrixserverlib.ServerName, 2)
@@ -357,7 +376,7 @@ func sendToRemoteServer(
 	}
 
 	for _, server := range remoteServers {
-		err = federation.ExchangeThirdPartyInvite(ctx, server, builder)
+		err = federation.ExchangeThirdPartyInvite(ctx, cfg.Matrix.ServerName, server, builder)
 		if err == nil {
 			return
 		}

go.mod

@@ -22,7 +22,7 @@ require (
 	github.com/matrix-org/dugong v0.0.0-20210921133753-66e6b1c67e2e
 	github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91
 	github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530
-	github.com/matrix-org/gomatrixserverlib v0.0.0-20221109092408-715dc88e62e2
+	github.com/matrix-org/gomatrixserverlib v0.0.0-20221111172904-e8fa860b1cdf
 	github.com/matrix-org/pinecone v0.0.0-20221103125849-37f2e9b9ba37
 	github.com/matrix-org/util v0.0.0-20200807132607-55161520e1d4
 	github.com/mattn/go-sqlite3 v1.14.15

go.sum

@@ -348,8 +348,8 @@ github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91 h1:s7fexw
 github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91/go.mod h1:e+cg2q7C7yE5QnAXgzo512tgFh1RbQLC0+jozuegKgo=
 github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530 h1:kHKxCOLcHH8r4Fzarl4+Y3K5hjothkVW5z7T1dUM11U=
 github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530/go.mod h1:/gBX06Kw0exX1HrwmoBibFA98yBk/jxKpGVeyQbff+s=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20221109092408-715dc88e62e2 h1:Bet5n+//Yh+A2SuPHD67N8jrOhC/EIKvEgisfsKhTss=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20221109092408-715dc88e62e2/go.mod h1:Mtifyr8q8htcBeugvlDnkBcNUy5LO8OzUoplAf1+mb4=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20221111172904-e8fa860b1cdf h1:OPM8urHlGC8m1MfusZg6Oi9zxJiDNuSVh3GQuvZeOHw=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20221111172904-e8fa860b1cdf/go.mod h1:Mtifyr8q8htcBeugvlDnkBcNUy5LO8OzUoplAf1+mb4=
 github.com/matrix-org/pinecone v0.0.0-20221103125849-37f2e9b9ba37 h1:CQWFrgH9TJOU2f2qCDhGwaSdAnmgSu3/f+2xcf/Fse4=
 github.com/matrix-org/pinecone v0.0.0-20221103125849-37f2e9b9ba37/go.mod h1:F3GHppRuHCTDeoOmmgjZMeJdbql91+RSGGsATWfC7oc=
 github.com/matrix-org/util v0.0.0-20200807132607-55161520e1d4 h1:eCEHXWDv9Rm335MSuB49mFUK44bwZPFSDde3ORE3syk=

internal/eventutil/events.go

@@ -38,7 +38,8 @@ var ErrRoomNoExists = errors.New("room does not exist")
 // Returns an error if something else went wrong
 func QueryAndBuildEvent(
 	ctx context.Context,
-	builder *gomatrixserverlib.EventBuilder, cfg *config.Global, evTime time.Time,
+	builder *gomatrixserverlib.EventBuilder, cfg *config.Global,
+	identity *gomatrixserverlib.SigningIdentity, evTime time.Time,
 	rsAPI api.QueryLatestEventsAndStateAPI, queryRes *api.QueryLatestEventsAndStateResponse,
 ) (*gomatrixserverlib.HeaderedEvent, error) {
 	if queryRes == nil {
@@ -50,24 +51,24 @@ func QueryAndBuildEvent(
 		// This can pass through a ErrRoomNoExists to the caller
 		return nil, err
 	}
-	return BuildEvent(ctx, builder, cfg, evTime, eventsNeeded, queryRes)
+	return BuildEvent(ctx, builder, cfg, identity, evTime, eventsNeeded, queryRes)
 }
 
 // BuildEvent builds a Matrix event from the builder and QueryLatestEventsAndStateResponse
 // provided.
 func BuildEvent(
 	ctx context.Context,
-	builder *gomatrixserverlib.EventBuilder, cfg *config.Global, evTime time.Time,
+	builder *gomatrixserverlib.EventBuilder, cfg *config.Global,
+	identity *gomatrixserverlib.SigningIdentity, evTime time.Time,
 	eventsNeeded *gomatrixserverlib.StateNeeded, queryRes *api.QueryLatestEventsAndStateResponse,
 ) (*gomatrixserverlib.HeaderedEvent, error) {
-	err := addPrevEventsToEvent(builder, eventsNeeded, queryRes)
-	if err != nil {
+	if err := addPrevEventsToEvent(builder, eventsNeeded, queryRes); err != nil {
 		return nil, err
 	}
 
 	event, err := builder.Build(
-		evTime, cfg.ServerName, cfg.KeyID,
-		cfg.PrivateKey, queryRes.RoomVersion,
+		evTime, identity.ServerName, identity.KeyID,
+		identity.PrivateKey, queryRes.RoomVersion,
 	)
 	if err != nil {
 		return nil, err

keyserver/consumers/devicelistupdate.go

@@ -30,12 +30,12 @@ import (
 
 // DeviceListUpdateConsumer consumes device list updates that came in over federation.
 type DeviceListUpdateConsumer struct {
-	ctx        context.Context
-	jetstream  nats.JetStreamContext
-	durable    string
-	topic      string
-	updater    *internal.DeviceListUpdater
-	serverName gomatrixserverlib.ServerName
+	ctx               context.Context
+	jetstream         nats.JetStreamContext
+	durable           string
+	topic             string
+	updater           *internal.DeviceListUpdater
+	isLocalServerName func(gomatrixserverlib.ServerName) bool
 }
 
 // NewDeviceListUpdateConsumer creates a new DeviceListConsumer. Call Start() to begin consuming from key servers.
@@ -46,12 +46,12 @@ func NewDeviceListUpdateConsumer(
 	updater *internal.DeviceListUpdater,
 ) *DeviceListUpdateConsumer {
 	return &DeviceListUpdateConsumer{
-		ctx:        process.Context(),
-		jetstream:  js,
-		durable:    cfg.Matrix.JetStream.Prefixed("KeyServerInputDeviceListConsumer"),
-		topic:      cfg.Matrix.JetStream.Prefixed(jetstream.InputDeviceListUpdate),
-		updater:    updater,
-		serverName: cfg.Matrix.ServerName,
+		ctx:               process.Context(),
+		jetstream:         js,
+		durable:           cfg.Matrix.JetStream.Prefixed("KeyServerInputDeviceListConsumer"),
+		topic:             cfg.Matrix.JetStream.Prefixed(jetstream.InputDeviceListUpdate),
+		updater:           updater,
+		isLocalServerName: cfg.Matrix.IsLocalServerName,
 	}
 }
 
@@ -75,7 +75,7 @@ func (t *DeviceListUpdateConsumer) onMessage(ctx context.Context, msgs []*nats.M
 	origin := gomatrixserverlib.ServerName(msg.Header.Get("origin"))
 	if _, serverName, err := gomatrixserverlib.SplitID('@', m.UserID); err != nil {
 		return true
-	} else if serverName == t.serverName {
+	} else if t.isLocalServerName(serverName) {
 		return true
 	} else if serverName != origin {
 		return true

keyserver/consumers/signingkeyupdate.go

@@ -31,12 +31,13 @@ import (
 
 // SigningKeyUpdateConsumer consumes signing key updates that came in over federation.
 type SigningKeyUpdateConsumer struct {
-	ctx       context.Context
-	jetstream nats.JetStreamContext
-	durable   string
-	topic     string
-	keyAPI    *internal.KeyInternalAPI
-	cfg       *config.KeyServer
+	ctx               context.Context
+	jetstream         nats.JetStreamContext
+	durable           string
+	topic             string
+	keyAPI            *internal.KeyInternalAPI
+	cfg               *config.KeyServer
+	isLocalServerName func(gomatrixserverlib.ServerName) bool
 }
 
 // NewSigningKeyUpdateConsumer creates a new SigningKeyUpdateConsumer. Call Start() to begin consuming from key servers.
@@ -47,12 +48,13 @@ func NewSigningKeyUpdateConsumer(
 	keyAPI *internal.KeyInternalAPI,
 ) *SigningKeyUpdateConsumer {
 	return &SigningKeyUpdateConsumer{
-		ctx:       process.Context(),
-		jetstream: js,
-		durable:   cfg.Matrix.JetStream.Prefixed("KeyServerSigningKeyConsumer"),
-		topic:     cfg.Matrix.JetStream.Prefixed(jetstream.InputSigningKeyUpdate),
-		keyAPI:    keyAPI,
-		cfg:       cfg,
+		ctx:               process.Context(),
+		jetstream:         js,
+		durable:           cfg.Matrix.JetStream.Prefixed("KeyServerSigningKeyConsumer"),
+		topic:             cfg.Matrix.JetStream.Prefixed(jetstream.InputSigningKeyUpdate),
+		keyAPI:            keyAPI,
+		cfg:               cfg,
+		isLocalServerName: cfg.Matrix.IsLocalServerName,
 	}
 }
 
@@ -77,7 +79,7 @@ func (t *SigningKeyUpdateConsumer) onMessage(ctx context.Context, msgs []*nats.M
 	if _, serverName, err := gomatrixserverlib.SplitID('@', updatePayload.UserID); err != nil {
 		logrus.WithError(err).Error("failed to split user id")
 		return true
-	} else if serverName == t.cfg.Matrix.ServerName {
+	} else if t.isLocalServerName(serverName) {
 		logrus.Warn("dropping device key update from ourself")
 		return true
 	} else if serverName != origin {

keyserver/internal/device_list_update.go

@@ -96,6 +96,7 @@ type DeviceListUpdater struct {
 	producer    KeyChangeProducer
 	fedClient   fedsenderapi.KeyserverFederationAPI
 	workerChans []chan gomatrixserverlib.ServerName
+	thisServer  gomatrixserverlib.ServerName
 
 	// When device lists are stale for a user, they get inserted into this map with a channel which `Update` will
 	// block on or timeout via a select.
@@ -139,6 +140,7 @@ func NewDeviceListUpdater(
 	process *process.ProcessContext, db DeviceListUpdaterDatabase,
 	api DeviceListUpdaterAPI, producer KeyChangeProducer,
 	fedClient fedsenderapi.KeyserverFederationAPI, numWorkers int,
+	thisServer gomatrixserverlib.ServerName,
 ) *DeviceListUpdater {
 	return &DeviceListUpdater{
 		process:        process,
@@ -148,6 +150,7 @@ func NewDeviceListUpdater(
 		api:            api,
 		producer:       producer,
 		fedClient:      fedClient,
+		thisServer:     thisServer,
 		workerChans:    make([]chan gomatrixserverlib.ServerName, numWorkers),
 		userIDToChan:   make(map[string]chan bool),
 		userIDToChanMu: &sync.Mutex{},
@@ -435,8 +438,7 @@ func (u *DeviceListUpdater) processServerUser(ctx context.Context, serverName go
 		"server_name": serverName,
 		"user_id":     userID,
 	})
-
-	res, err := u.fedClient.GetUserDevices(ctx, serverName, userID)
+	res, err := u.fedClient.GetUserDevices(ctx, u.thisServer, serverName, userID)
 	if err != nil {
 		if errors.Is(err, context.DeadlineExceeded) {
 			return time.Minute * 10, err

keyserver/internal/device_list_update_test.go

@@ -129,7 +129,13 @@ func (t *roundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
 func newFedClient(tripper func(*http.Request) (*http.Response, error)) *gomatrixserverlib.FederationClient {
 	_, pkey, _ := ed25519.GenerateKey(nil)
 	fedClient := gomatrixserverlib.NewFederationClient(
-		gomatrixserverlib.ServerName("example.test"), gomatrixserverlib.KeyID("ed25519:test"), pkey,
+		[]*gomatrixserverlib.SigningIdentity{
+			{
+				ServerName: gomatrixserverlib.ServerName("example.test"),
+				KeyID:      gomatrixserverlib.KeyID("ed25519:test"),
+				PrivateKey: pkey,
+			},
+		},
 	)
 	fedClient.Client = *gomatrixserverlib.NewClient(
 		gomatrixserverlib.WithTransport(&roundTripper{tripper}),
@@ -147,7 +153,7 @@ func TestUpdateHavePrevID(t *testing.T) {
 	}
 	ap := &mockDeviceListUpdaterAPI{}
 	producer := &mockKeyChangeProducer{}
-	updater := NewDeviceListUpdater(process.NewProcessContext(), db, ap, producer, nil, 1)
+	updater := NewDeviceListUpdater(process.NewProcessContext(), db, ap, producer, nil, 1, "localhost")
 	event := gomatrixserverlib.DeviceListUpdateEvent{
 		DeviceDisplayName: "Foo Bar",
 		Deleted:           false,
@@ -219,7 +225,7 @@ func TestUpdateNoPrevID(t *testing.T) {
 			`)),
 		}, nil
 	})
-	updater := NewDeviceListUpdater(process.NewProcessContext(), db, ap, producer, fedClient, 2)
+	updater := NewDeviceListUpdater(process.NewProcessContext(), db, ap, producer, fedClient, 2, "example.test")
 	if err := updater.Start(); err != nil {
 		t.Fatalf("failed to start updater: %s", err)
 	}
@@ -288,7 +294,7 @@ func TestDebounce(t *testing.T) {
 		close(incomingFedReq)
 		return <-fedCh, nil
 	})
-	updater := NewDeviceListUpdater(process.NewProcessContext(), db, ap, producer, fedClient, 1)
+	updater := NewDeviceListUpdater(process.NewProcessContext(), db, ap, producer, fedClient, 1, "localhost")
 	if err := updater.Start(); err != nil {
 		t.Fatalf("failed to start updater: %s", err)
 	}

keyserver/internal/internal.go

@@ -146,7 +146,7 @@ func (a *KeyInternalAPI) claimRemoteKeys(
 			defer cancel()
 			defer wg.Done()
 
-			claimKeyRes, err := a.FedClient.ClaimKeys(fedCtx, gomatrixserverlib.ServerName(domain), keysToClaim)
+			claimKeyRes, err := a.FedClient.ClaimKeys(fedCtx, a.Cfg.Matrix.ServerName, gomatrixserverlib.ServerName(domain), keysToClaim)
 
 			mu.Lock()
 			defer mu.Unlock()
@@ -559,7 +559,7 @@ func (a *KeyInternalAPI) queryRemoteKeysOnServer(
 	if len(devKeys) == 0 {
 		return
 	}
-	queryKeysResp, err := a.FedClient.QueryKeys(fedCtx, gomatrixserverlib.ServerName(serverName), devKeys)
+	queryKeysResp, err := a.FedClient.QueryKeys(fedCtx, a.Cfg.Matrix.ServerName, gomatrixserverlib.ServerName(serverName), devKeys)
 	if err == nil {
 		resultCh <- &queryKeysResp
 		return

keyserver/keyserver.go

@@ -58,7 +58,7 @@ func NewInternalAPI(
 		FedClient: fedClient,
 		Producer:  keyChangeProducer,
 	}
-	updater := internal.NewDeviceListUpdater(base.ProcessContext, db, ap, keyChangeProducer, fedClient, 8) // 8 workers TODO: configurable
+	updater := internal.NewDeviceListUpdater(base.ProcessContext, db, ap, keyChangeProducer, fedClient, 8, cfg.Matrix.ServerName) // 8 workers TODO: configurable
 	ap.Updater = updater
 	go func() {
 		if err := updater.Start(); err != nil {

roomserver/api/input.go

@@ -94,8 +94,9 @@ type TransactionID struct {
 
 // InputRoomEventsRequest is a request to InputRoomEvents
 type InputRoomEventsRequest struct {
-	InputRoomEvents []InputRoomEvent `json:"input_room_events"`
-	Asynchronous    bool             `json:"async"`
+	InputRoomEvents []InputRoomEvent             `json:"input_room_events"`
+	Asynchronous    bool                         `json:"async"`
+	VirtualHost     gomatrixserverlib.ServerName `json:"virtual_host"`
 }
 
 // InputRoomEventsResponse is a response to InputRoomEvents

roomserver/api/perform.go

@@ -148,6 +148,8 @@ type PerformBackfillRequest struct {
 	Limit int `json:"limit"`
 	// The server interested in the events.
 	ServerName gomatrixserverlib.ServerName `json:"server_name"`
+	// Which virtual host are we doing this for?
+	VirtualHost gomatrixserverlib.ServerName `json:"virtual_host"`
 }
 
 // PrevEventIDs returns the prev_event IDs of all backwards extremities, de-duplicated in a lexicographically sorted order.

roomserver/api/wrapper.go

@@ -26,7 +26,7 @@ import (
 func SendEvents(
 	ctx context.Context, rsAPI InputRoomEventsAPI,
 	kind Kind, events []*gomatrixserverlib.HeaderedEvent,
-	origin gomatrixserverlib.ServerName,
+	virtualHost, origin gomatrixserverlib.ServerName,
 	sendAsServer gomatrixserverlib.ServerName, txnID *TransactionID,
 	async bool,
 ) error {
@@ -40,14 +40,15 @@ func SendEvents(
 			TransactionID: txnID,
 		}
 	}
-	return SendInputRoomEvents(ctx, rsAPI, ires, async)
+	return SendInputRoomEvents(ctx, rsAPI, virtualHost, ires, async)
 }
 
 // SendEventWithState writes an event with the specified kind to the roomserver
 // with the state at the event as KindOutlier before it. Will not send any event that is
 // marked as `true` in haveEventIDs.
 func SendEventWithState(
-	ctx context.Context, rsAPI InputRoomEventsAPI, kind Kind,
+	ctx context.Context, rsAPI InputRoomEventsAPI,
+	virtualHost gomatrixserverlib.ServerName, kind Kind,
 	state *gomatrixserverlib.RespState, event *gomatrixserverlib.HeaderedEvent,
 	origin gomatrixserverlib.ServerName, haveEventIDs map[string]bool, async bool,
 ) error {
@@ -85,17 +86,19 @@ func SendEventWithState(
 		StateEventIDs: stateEventIDs,
 	})
 
-	return SendInputRoomEvents(ctx, rsAPI, ires, async)
+	return SendInputRoomEvents(ctx, rsAPI, virtualHost, ires, async)
 }
 
 // SendInputRoomEvents to the roomserver.
 func SendInputRoomEvents(
 	ctx context.Context, rsAPI InputRoomEventsAPI,
+	virtualHost gomatrixserverlib.ServerName,
 	ires []InputRoomEvent, async bool,
 ) error {
 	request := InputRoomEventsRequest{
 		InputRoomEvents: ires,
 		Asynchronous:    async,
+		VirtualHost:     virtualHost,
 	}
 	var response InputRoomEventsResponse
 	if err := rsAPI.InputRoomEvents(ctx, &request, &response); err != nil {

roomserver/internal/alias.go

@@ -137,6 +137,11 @@ func (r *RoomserverInternalAPI) RemoveRoomAlias(
 	request *api.RemoveRoomAliasRequest,
 	response *api.RemoveRoomAliasResponse,
 ) error {
+	_, virtualHost, err := r.Cfg.Matrix.SplitLocalID('@', request.UserID)
+	if err != nil {
+		return err
+	}
+
 	roomID, err := r.DB.GetRoomIDForAlias(ctx, request.Alias)
 	if err != nil {
 		return fmt.Errorf("r.DB.GetRoomIDForAlias: %w", err)
@@ -190,6 +195,16 @@ func (r *RoomserverInternalAPI) RemoveRoomAlias(
 				sender = ev.Sender()
 			}
 
+			_, senderDomain, err := r.Cfg.Matrix.SplitLocalID('@', sender)
+			if err != nil {
+				return err
+			}
+
+			identity, err := r.Cfg.Matrix.SigningIdentityFor(senderDomain)
+			if err != nil {
+				return err
+			}
+
 			builder := &gomatrixserverlib.EventBuilder{
 				Sender:   sender,
 				RoomID:   ev.RoomID(),
@@ -211,12 +226,12 @@ func (r *RoomserverInternalAPI) RemoveRoomAlias(
 				return err
 			}
 
-			newEvent, err := eventutil.BuildEvent(ctx, builder, r.Cfg.Matrix, time.Now(), &eventsNeeded, stateRes)
+			newEvent, err := eventutil.BuildEvent(ctx, builder, r.Cfg.Matrix, identity, time.Now(), &eventsNeeded, stateRes)
 			if err != nil {
 				return err
 			}
 
-			err = api.SendEvents(ctx, r, api.KindNew, []*gomatrixserverlib.HeaderedEvent{newEvent}, r.ServerName, r.ServerName, nil, false)
+			err = api.SendEvents(ctx, r, api.KindNew, []*gomatrixserverlib.HeaderedEvent{newEvent}, virtualHost, r.ServerName, r.ServerName, nil, false)
 			if err != nil {
 				return err
 			}

roomserver/internal/api.go

@@ -87,10 +87,10 @@ func NewRoomserverAPI(
 		Durable:                base.Cfg.Global.JetStream.Durable("RoomserverInputConsumer"),
 		ServerACLs:             serverACLs,
 		Queryer: &query.Queryer{
-			DB:         roomserverDB,
-			Cache:      base.Caches,
-			ServerName: base.Cfg.Global.ServerName,
-			ServerACLs: serverACLs,
+			DB:                roomserverDB,
+			Cache:             base.Caches,
+			IsLocalServerName: base.Cfg.Global.IsLocalServerName,
+			ServerACLs:        serverACLs,
 		},
 		// perform-er structs get initialised when we have a federation sender to use
 	}
@@ -127,13 +127,12 @@ func (r *RoomserverInternalAPI) SetFederationAPI(fsAPI fsAPI.RoomserverFederatio
 		Inputer: r.Inputer,
 	}
 	r.Joiner = &perform.Joiner{
-		ServerName: r.Cfg.Matrix.ServerName,
-		Cfg:        r.Cfg,
-		DB:         r.DB,
-		FSAPI:      r.fsAPI,
-		RSAPI:      r,
-		Inputer:    r.Inputer,
-		Queryer:    r.Queryer,
+		Cfg:     r.Cfg,
+		DB:      r.DB,
+		FSAPI:   r.fsAPI,
+		RSAPI:   r,
+		Inputer: r.Inputer,
+		Queryer: r.Queryer,
 	}
 	r.Peeker = &perform.Peeker{
 		ServerName: r.Cfg.Matrix.ServerName,
@@ -163,10 +162,10 @@ func (r *RoomserverInternalAPI) SetFederationAPI(fsAPI fsAPI.RoomserverFederatio
 		DB: r.DB,
 	}
 	r.Backfiller = &perform.Backfiller{
-		ServerName: r.ServerName,
-		DB:         r.DB,
-		FSAPI:      r.fsAPI,
-		KeyRing:    r.KeyRing,
+		IsLocalServerName: r.Cfg.Matrix.IsLocalServerName,
+		DB:                r.DB,
+		FSAPI:             r.fsAPI,
+		KeyRing:           r.KeyRing,
 		// Perspective servers are trusted to not lie about server keys, so we will also
 		// prefer these servers when backfilling (assuming they are in the room) rather
 		// than trying random servers

roomserver/internal/input/input.go

@@ -278,7 +278,11 @@ func (w *worker) _next() {
 	// a string, because we might want to return that to the caller if
 	// it was a synchronous request.
 	var errString string
-	if err = w.r.processRoomEvent(w.r.ProcessContext.Context(), &inputRoomEvent); err != nil {
+	if err = w.r.processRoomEvent(
+		w.r.ProcessContext.Context(),
+		gomatrixserverlib.ServerName(msg.Header.Get("virtual_host")),
+		&inputRoomEvent,
+	); err != nil {
 		switch err.(type) {
 		case types.RejectedError:
 			// Don't send events that were rejected to Sentry
@@ -358,6 +362,7 @@ func (r *Inputer) queueInputRoomEvents(
 		if replyTo != "" {
 			msg.Header.Set("sync", replyTo)
 		}
+		msg.Header.Set("virtual_host", string(request.VirtualHost))
 		msg.Data, err = json.Marshal(e)
 		if err != nil {
 			return nil, fmt.Errorf("json.Marshal: %w", err)

roomserver/internal/input/input_events.go

@@ -69,6 +69,7 @@ var processRoomEventDuration = prometheus.NewHistogramVec(
 // nolint:gocyclo
 func (r *Inputer) processRoomEvent(
 	ctx context.Context,
+	virtualHost gomatrixserverlib.ServerName,
 	input *api.InputRoomEvent,
 ) error {
 	select {
@@ -200,7 +201,7 @@ func (r *Inputer) processRoomEvent(
 	isRejected := false
 	authEvents := gomatrixserverlib.NewAuthEvents(nil)
 	knownEvents := map[string]*types.Event{}
-	if err = r.fetchAuthEvents(ctx, logger, roomInfo, headered, &authEvents, knownEvents, serverRes.ServerNames); err != nil {
+	if err = r.fetchAuthEvents(ctx, logger, roomInfo, virtualHost, headered, &authEvents, knownEvents, serverRes.ServerNames); err != nil {
 		return fmt.Errorf("r.fetchAuthEvents: %w", err)
 	}
 
@@ -265,16 +266,17 @@ func (r *Inputer) processRoomEvent(
 		// processRoomEvent.
 		if len(serverRes.ServerNames) > 0 {
 			missingState := missingStateReq{
-				origin:     input.Origin,
-				inputer:    r,
-				db:         r.DB,
-				roomInfo:   roomInfo,
-				federation: r.FSAPI,
-				keys:       r.KeyRing,
-				roomsMu:    internal.NewMutexByRoom(),
-				servers:    serverRes.ServerNames,
-				hadEvents:  map[string]bool{},
-				haveEvents: map[string]*gomatrixserverlib.Event{},
+				origin:      input.Origin,
+				virtualHost: virtualHost,
+				inputer:     r,
+				db:          r.DB,
+				roomInfo:    roomInfo,
+				federation:  r.FSAPI,
+				keys:        r.KeyRing,
+				roomsMu:     internal.NewMutexByRoom(),
+				servers:     serverRes.ServerNames,
+				hadEvents:   map[string]bool{},
+				haveEvents:  map[string]*gomatrixserverlib.Event{},
 			}
 			var stateSnapshot *parsedRespState
 			if stateSnapshot, err = missingState.processEventWithMissingState(ctx, event, headered.RoomVersion); err != nil {
@@ -555,6 +557,7 @@ func (r *Inputer) fetchAuthEvents(
 	ctx context.Context,
 	logger *logrus.Entry,
 	roomInfo *types.RoomInfo,
+	virtualHost gomatrixserverlib.ServerName,
 	event *gomatrixserverlib.HeaderedEvent,
 	auth *gomatrixserverlib.AuthEvents,
 	known map[string]*types.Event,
@@ -605,7 +608,7 @@ func (r *Inputer) fetchAuthEvents(
 		// Request the entire auth chain for the event in question. This should
 		// contain all of the auth events — including ones that we already know —
 		// so we'll need to filter through those in the next section.
-		res, err = r.FSAPI.GetEventAuth(ctx, serverName, event.RoomVersion, event.RoomID(), event.EventID())
+		res, err = r.FSAPI.GetEventAuth(ctx, virtualHost, serverName, event.RoomVersion, event.RoomID(), event.EventID())
 		if err != nil {
 			logger.WithError(err).Warnf("Failed to get event auth from federation for %q: %s", event.EventID(), err)
 			continue

roomserver/internal/input/input_missing.go

@@ -41,6 +41,7 @@ func (p *parsedRespState) Events() []*gomatrixserverlib.Event {
 
 type missingStateReq struct {
 	log             *logrus.Entry
+	virtualHost     gomatrixserverlib.ServerName
 	origin          gomatrixserverlib.ServerName
 	db              storage.Database
 	roomInfo        *types.RoomInfo
@@ -101,7 +102,7 @@ func (t *missingStateReq) processEventWithMissingState(
 		// we can just inject all the newEvents as new as we may have only missed 1 or 2 events and have filled
 		// in the gap in the DAG
 		for _, newEvent := range newEvents {
-			err = t.inputer.processRoomEvent(ctx, &api.InputRoomEvent{
+			err = t.inputer.processRoomEvent(ctx, t.virtualHost, &api.InputRoomEvent{
 				Kind:         api.KindOld,
 				Event:        newEvent.Headered(roomVersion),
 				Origin:       t.origin,
@@ -157,7 +158,7 @@ func (t *missingStateReq) processEventWithMissingState(
 			})
 		}
 		for _, ire := range outlierRoomEvents {
-			if err = t.inputer.processRoomEvent(ctx, &ire); err != nil {
+			if err = t.inputer.processRoomEvent(ctx, t.virtualHost, &ire); err != nil {
 				if _, ok := err.(types.RejectedError); !ok {
 					return fmt.Errorf("t.inputer.processRoomEvent (outlier): %w", err)
 				}
@@ -180,7 +181,7 @@ func (t *missingStateReq) processEventWithMissingState(
 		stateIDs = append(stateIDs, event.EventID())
 	}
 
-	err = t.inputer.processRoomEvent(ctx, &api.InputRoomEvent{
+	err = t.inputer.processRoomEvent(ctx, t.virtualHost, &api.InputRoomEvent{
 		Kind:          api.KindOld,
 		Event:         backwardsExtremity.Headered(roomVersion),
 		Origin:        t.origin,
@@ -199,7 +200,7 @@ func (t *missingStateReq) processEventWithMissingState(
 	// they will automatically fast-forward based on the room state at the
 	// extremity in the last step.
 	for _, newEvent := range newEvents {
-		err = t.inputer.processRoomEvent(ctx, &api.InputRoomEvent{
+		err = t.inputer.processRoomEvent(ctx, t.virtualHost, &api.InputRoomEvent{
 			Kind:         api.KindOld,
 			Event:        newEvent.Headered(roomVersion),
 			Origin:       t.origin,
@@ -519,7 +520,7 @@ func (t *missingStateReq) getMissingEvents(ctx context.Context, e *gomatrixserve
 	var missingResp *gomatrixserverlib.RespMissingEvents
 	for _, server := range t.servers {
 		var m gomatrixserverlib.RespMissingEvents
-		if m, err = t.federation.LookupMissingEvents(ctx, server, e.RoomID(), gomatrixserverlib.MissingEvents{
+		if m, err = t.federation.LookupMissingEvents(ctx, t.virtualHost, server, e.RoomID(), gomatrixserverlib.MissingEvents{
 			Limit: 20,
 			// The latest event IDs that the sender already has. These are skipped when retrieving the previous events of latest_events.
 			EarliestEvents: latestEvents,
@@ -635,7 +636,7 @@ func (t *missingStateReq) lookupMissingStateViaState(
 	span, ctx := opentracing.StartSpanFromContext(ctx, "lookupMissingStateViaState")
 	defer span.Finish()
 
-	state, err := t.federation.LookupState(ctx, t.origin, roomID, eventID, roomVersion)
+	state, err := t.federation.LookupState(ctx, t.virtualHost, t.origin, roomID, eventID, roomVersion)
 	if err != nil {
 		return nil, err
 	}
@@ -675,7 +676,7 @@ func (t *missingStateReq) lookupMissingStateViaStateIDs(ctx context.Context, roo
 	totalctx, totalcancel := context.WithTimeout(ctx, time.Minute*5)
 	for _, serverName := range t.servers {
 		reqctx, reqcancel := context.WithTimeout(totalctx, time.Second*20)
-		stateIDs, err = t.federation.LookupStateIDs(reqctx, serverName, roomID, eventID)
+		stateIDs, err = t.federation.LookupStateIDs(reqctx, t.virtualHost, serverName, roomID, eventID)
 		reqcancel()
 		if err == nil {
 			break
@@ -855,7 +856,7 @@ func (t *missingStateReq) lookupEvent(ctx context.Context, roomVersion gomatrixs
 	for _, serverName := range t.servers {
 		reqctx, cancel := context.WithTimeout(ctx, time.Second*30)
 		defer cancel()
-		txn, err := t.federation.GetEvent(reqctx, serverName, missingEventID)
+		txn, err := t.federation.GetEvent(reqctx, t.virtualHost, serverName, missingEventID)
 		if err != nil || len(txn.PDUs) == 0 {
 			t.log.WithError(err).WithField("missing_event_id", missingEventID).Warn("Failed to get missing /event for event ID")
 			if errors.Is(err, context.DeadlineExceeded) {

roomserver/internal/perform/perform_admin.go

@@ -139,7 +139,12 @@ func (r *Admin) PerformAdminEvacuateRoom(
 			return nil
 		}
 
-		event, err := eventutil.BuildEvent(ctx, fledglingEvent, r.Cfg.Matrix, time.Now(), &eventsNeeded, latestRes)
+		identity, err := r.Cfg.Matrix.SigningIdentityFor(senderDomain)
+		if err != nil {
+			continue
+		}
+
+		event, err := eventutil.BuildEvent(ctx, fledglingEvent, r.Cfg.Matrix, identity, time.Now(), &eventsNeeded, latestRes)
 		if err != nil {
 			res.Error = &api.PerformError{
 				Code: api.PerformErrorBadRequest,
@@ -242,6 +247,15 @@ func (r *Admin) PerformAdminDownloadState(
 	req *api.PerformAdminDownloadStateRequest,
 	res *api.PerformAdminDownloadStateResponse,
 ) error {
+	_, senderDomain, err := r.Cfg.Matrix.SplitLocalID('@', req.UserID)
+	if err != nil {
+		res.Error = &api.PerformError{
+			Code: api.PerformErrorBadRequest,
+			Msg:  fmt.Sprintf("r.Cfg.Matrix.SplitLocalID: %s", err),
+		}
+		return nil
+	}
+
 	roomInfo, err := r.DB.RoomInfo(ctx, req.RoomID)
 	if err != nil {
 		res.Error = &api.PerformError{
@@ -273,7 +287,7 @@ func (r *Admin) PerformAdminDownloadState(
 
 	for _, fwdExtremity := range fwdExtremities {
 		var state gomatrixserverlib.RespState
-		state, err = r.Inputer.FSAPI.LookupState(ctx, req.ServerName, req.RoomID, fwdExtremity.EventID, roomInfo.RoomVersion)
+		state, err = r.Inputer.FSAPI.LookupState(ctx, r.Inputer.ServerName, req.ServerName, req.RoomID, fwdExtremity.EventID, roomInfo.RoomVersion)
 		if err != nil {
 			res.Error = &api.PerformError{
 				Code: api.PerformErrorBadRequest,
@@ -331,7 +345,12 @@ func (r *Admin) PerformAdminDownloadState(
 		Depth:        depth,
 	}
 
-	ev, err := eventutil.BuildEvent(ctx, builder, r.Cfg.Matrix, time.Now(), &eventsNeeded, queryRes)
+	identity, err := r.Cfg.Matrix.SigningIdentityFor(senderDomain)
+	if err != nil {
+		return err
+	}
+
+	ev, err := eventutil.BuildEvent(ctx, builder, r.Cfg.Matrix, identity, time.Now(), &eventsNeeded, queryRes)
 	if err != nil {
 		res.Error = &api.PerformError{
 			Code: api.PerformErrorBadRequest,

roomserver/internal/perform/perform_backfill.go

@@ -37,10 +37,10 @@ import (
 const maxBackfillServers = 5
 
 type Backfiller struct {
-	ServerName gomatrixserverlib.ServerName
-	DB         storage.Database
-	FSAPI      federationAPI.RoomserverFederationAPI
-	KeyRing    gomatrixserverlib.JSONVerifier
+	IsLocalServerName func(gomatrixserverlib.ServerName) bool
+	DB                storage.Database
+	FSAPI             federationAPI.RoomserverFederationAPI
+	KeyRing           gomatrixserverlib.JSONVerifier
 
 	// The servers which should be preferred above other servers when backfilling
 	PreferServers []gomatrixserverlib.ServerName
@@ -55,7 +55,7 @@ func (r *Backfiller) PerformBackfill(
 	// if we are requesting the backfill then we need to do a federation hit
 	// TODO: we could be more sensible and fetch as many events we already have then request the rest
 	//       which is what the syncapi does already.
-	if request.ServerName == r.ServerName {
+	if r.IsLocalServerName(request.ServerName) {
 		return r.backfillViaFederation(ctx, request, response)
 	}
 	// someone else is requesting the backfill, try to service their request.
@@ -112,16 +112,18 @@ func (r *Backfiller) backfillViaFederation(ctx context.Context, req *api.Perform
 	if info == nil || info.IsStub() {
 		return fmt.Errorf("backfillViaFederation: missing room info for room %s", req.RoomID)
 	}
-	requester := newBackfillRequester(r.DB, r.FSAPI, r.ServerName, req.BackwardsExtremities, r.PreferServers)
+	requester := newBackfillRequester(r.DB, r.FSAPI, req.VirtualHost, r.IsLocalServerName, req.BackwardsExtremities, r.PreferServers)
 	// Request 100 items regardless of what the query asks for.
 	// We don't want to go much higher than this.
 	// We can't honour exactly the limit as some sytests rely on requesting more for tests to pass
 	// (so we don't need to hit /state_ids which the test has no listener for)
 	// Specifically the test "Outbound federation can backfill events"
 	events, err := gomatrixserverlib.RequestBackfill(
-		ctx, requester,
-		r.KeyRing, req.RoomID, info.RoomVersion, req.PrevEventIDs(), 100)
+		ctx, req.VirtualHost, requester,
+		r.KeyRing, req.RoomID, info.RoomVersion, req.PrevEventIDs(), 100,
+	)
 	if err != nil {
+		logrus.WithError(err).Errorf("gomatrixserverlib.RequestBackfill failed")
 		return err
 	}
 	logrus.WithField("room_id", req.RoomID).Infof("backfilled %d events", len(events))
@@ -144,7 +146,7 @@ func (r *Backfiller) backfillViaFederation(ctx context.Context, req *api.Perform
 		var entries []types.StateEntry
 		if entries, err = r.DB.StateEntriesForEventIDs(ctx, stateIDs, true); err != nil {
 			// attempt to fetch the missing events
-			r.fetchAndStoreMissingEvents(ctx, info.RoomVersion, requester, stateIDs)
+			r.fetchAndStoreMissingEvents(ctx, info.RoomVersion, requester, stateIDs, req.VirtualHost)
 			// try again
 			entries, err = r.DB.StateEntriesForEventIDs(ctx, stateIDs, true)
 			if err != nil {
@@ -173,7 +175,7 @@ func (r *Backfiller) backfillViaFederation(ctx context.Context, req *api.Perform
 // fetchAndStoreMissingEvents does a best-effort fetch and store of missing events specified in stateIDs. Returns no error as it is just
 // best effort.
 func (r *Backfiller) fetchAndStoreMissingEvents(ctx context.Context, roomVer gomatrixserverlib.RoomVersion,
-	backfillRequester *backfillRequester, stateIDs []string) {
+	backfillRequester *backfillRequester, stateIDs []string, virtualHost gomatrixserverlib.ServerName) {
 
 	servers := backfillRequester.servers
 
@@ -198,7 +200,7 @@ func (r *Backfiller) fetchAndStoreMissingEvents(ctx context.Context, roomVer gom
 				continue // already found
 			}
 			logger := util.GetLogger(ctx).WithField("server", srv).WithField("event_id", id)
-			res, err := r.FSAPI.GetEvent(ctx, srv, id)
+			res, err := r.FSAPI.GetEvent(ctx, virtualHost, srv, id)
 			if err != nil {
 				logger.WithError(err).Warn("failed to get event from server")
 				continue
@@ -241,11 +243,12 @@ func (r *Backfiller) fetchAndStoreMissingEvents(ctx context.Context, roomVer gom
 
 // backfillRequester implements gomatrixserverlib.BackfillRequester
 type backfillRequester struct {
-	db           storage.Database
-	fsAPI        federationAPI.RoomserverFederationAPI
-	thisServer   gomatrixserverlib.ServerName
-	preferServer map[gomatrixserverlib.ServerName]bool
-	bwExtrems    map[string][]string
+	db                storage.Database
+	fsAPI             federationAPI.RoomserverFederationAPI
+	virtualHost       gomatrixserverlib.ServerName
+	isLocalServerName func(gomatrixserverlib.ServerName) bool
+	preferServer      map[gomatrixserverlib.ServerName]bool
+	bwExtrems         map[string][]string
 
 	// per-request state
 	servers                 []gomatrixserverlib.ServerName
@@ -255,7 +258,9 @@ type backfillRequester struct {
 }
 
 func newBackfillRequester(
-	db storage.Database, fsAPI federationAPI.RoomserverFederationAPI, thisServer gomatrixserverlib.ServerName,
+	db storage.Database, fsAPI federationAPI.RoomserverFederationAPI,
+	virtualHost gomatrixserverlib.ServerName,
+	isLocalServerName func(gomatrixserverlib.ServerName) bool,
 	bwExtrems map[string][]string, preferServers []gomatrixserverlib.ServerName,
 ) *backfillRequester {
 	preferServer := make(map[gomatrixserverlib.ServerName]bool)
@@ -265,7 +270,8 @@ func newBackfillRequester(
 	return &backfillRequester{
 		db:                      db,
 		fsAPI:                   fsAPI,
-		thisServer:              thisServer,
+		virtualHost:             virtualHost,
+		isLocalServerName:       isLocalServerName,
 		eventIDToBeforeStateIDs: make(map[string][]string),
 		eventIDMap:              make(map[string]*gomatrixserverlib.Event),
 		bwExtrems:               bwExtrems,
@@ -450,7 +456,7 @@ FindSuccessor:
 	}
 
 	// possibly return all joined servers depending on history visiblity
-	memberEventsFromVis, visibility, err := joinEventsFromHistoryVisibility(ctx, b.db, roomID, stateEntries, b.thisServer)
+	memberEventsFromVis, visibility, err := joinEventsFromHistoryVisibility(ctx, b.db, roomID, stateEntries, b.virtualHost)
 	b.historyVisiblity = visibility
 	if err != nil {
 		logrus.WithError(err).Error("ServersAtEvent: failed calculate servers from history visibility rules")
@@ -477,7 +483,7 @@ FindSuccessor:
 	}
 	var servers []gomatrixserverlib.ServerName
 	for server := range serverSet {
-		if server == b.thisServer {
+		if b.isLocalServerName(server) {
 			continue
 		}
 		if b.preferServer[server] { // insert at the front
@@ -496,10 +502,10 @@ FindSuccessor:
 
 // Backfill performs a backfill request to the given server.
 // https://matrix.org/docs/spec/server_server/latest#get-matrix-federation-v1-backfill-roomid
-func (b *backfillRequester) Backfill(ctx context.Context, server gomatrixserverlib.ServerName, roomID string,
+func (b *backfillRequester) Backfill(ctx context.Context, origin, server gomatrixserverlib.ServerName, roomID string,
 	limit int, fromEventIDs []string) (gomatrixserverlib.Transaction, error) {
 
-	tx, err := b.fsAPI.Backfill(ctx, server, roomID, limit, fromEventIDs)
+	tx, err := b.fsAPI.Backfill(ctx, origin, server, roomID, limit, fromEventIDs)
 	return tx, err
 }
 

roomserver/internal/perform/perform_join.go

@@ -39,11 +39,10 @@ import (
 )
 
 type Joiner struct {
-	ServerName gomatrixserverlib.ServerName
-	Cfg        *config.RoomServer
-	FSAPI      fsAPI.RoomserverFederationAPI
-	RSAPI      rsAPI.RoomserverInternalAPI
-	DB         storage.Database
+	Cfg   *config.RoomServer
+	FSAPI fsAPI.RoomserverFederationAPI
+	RSAPI rsAPI.RoomserverInternalAPI
+	DB    storage.Database
 
 	Inputer *input.Inputer
 	Queryer *query.Queryer
@@ -197,7 +196,7 @@ func (r *Joiner) performJoinRoomByID(
 
 	// Prepare the template for the join event.
 	userID := req.UserID
-	_, userDomain, err := gomatrixserverlib.SplitID('@', userID)
+	_, userDomain, err := r.Cfg.Matrix.SplitLocalID('@', userID)
 	if err != nil {
 		return "", "", &rsAPI.PerformError{
 			Code: rsAPI.PerformErrorBadRequest,
@@ -283,7 +282,7 @@ func (r *Joiner) performJoinRoomByID(
 	// locally on the homeserver.
 	// TODO: Check what happens if the room exists on the server
 	// but everyone has since left. I suspect it does the wrong thing.
-	event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, &eb)
+	event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, userDomain, &eb)
 
 	switch err {
 	case nil:
@@ -410,7 +409,9 @@ func (r *Joiner) populateAuthorisedViaUserForRestrictedJoin(
 }
 
 func buildEvent(
-	ctx context.Context, db storage.Database, cfg *config.Global, builder *gomatrixserverlib.EventBuilder,
+	ctx context.Context, db storage.Database, cfg *config.Global,
+	senderDomain gomatrixserverlib.ServerName,
+	builder *gomatrixserverlib.EventBuilder,
 ) (*gomatrixserverlib.HeaderedEvent, *rsAPI.QueryLatestEventsAndStateResponse, error) {
 	eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
 	if err != nil {
@@ -438,7 +439,12 @@ func buildEvent(
 		}
 	}
 
-	ev, err := eventutil.BuildEvent(ctx, builder, cfg, time.Now(), &eventsNeeded, &queryRes)
+	identity, err := cfg.SigningIdentityFor(senderDomain)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	ev, err := eventutil.BuildEvent(ctx, builder, cfg, identity, time.Now(), &eventsNeeded, &queryRes)
 	if err != nil {
 		return nil, nil, err
 	}

roomserver/internal/perform/perform_leave.go

@@ -162,21 +162,21 @@ func (r *Leaver) performLeaveRoomByID(
 		return nil, fmt.Errorf("eb.SetUnsigned: %w", err)
 	}
 
+	// Get the sender domain.
+	_, senderDomain, serr := r.Cfg.Matrix.SplitLocalID('@', eb.Sender)
+	if serr != nil {
+		return nil, fmt.Errorf("sender %q is invalid", eb.Sender)
+	}
+
 	// We know that the user is in the room at this point so let's build
 	// a leave event.
 	// TODO: Check what happens if the room exists on the server
 	// but everyone has since left. I suspect it does the wrong thing.
-	event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, &eb)
+	event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, senderDomain, &eb)
 	if err != nil {
 		return nil, fmt.Errorf("eventutil.BuildEvent: %w", err)
 	}
 
-	// Get the sender domain.
-	_, senderDomain, serr := gomatrixserverlib.SplitID('@', event.Sender())
-	if serr != nil {
-		return nil, fmt.Errorf("sender %q is invalid", event.Sender())
-	}
-
 	// Give our leave event to the roomserver input stream. The
 	// roomserver will process the membership change and notify
 	// downstream automatically.

roomserver/internal/perform/perform_upgrade.go

@@ -60,7 +60,7 @@ func (r *Upgrader) performRoomUpgrade(
 ) (string, *api.PerformError) {
 	roomID := req.RoomID
 	userID := req.UserID
-	_, userDomain, err := gomatrixserverlib.SplitID('@', userID)
+	_, userDomain, err := r.Cfg.Matrix.SplitLocalID('@', userID)
 	if err != nil {
 		return "", &api.PerformError{
 			Code: api.PerformErrorNotAllowed,
@@ -558,7 +558,7 @@ func (r *Upgrader) sendInitialEvents(ctx context.Context, evTime time.Time, user
 			SendAsServer: api.DoNotSendToOtherServers,
 		})
 	}
-	if err = api.SendInputRoomEvents(ctx, r.URSAPI, inputs, false); err != nil {
+	if err = api.SendInputRoomEvents(ctx, r.URSAPI, userDomain, inputs, false); err != nil {
 		return &api.PerformError{
 			Msg: fmt.Sprintf("Failed to send new room %q to roomserver: %s", newRoomID, err),
 		}
@@ -595,8 +595,21 @@ func (r *Upgrader) makeHeaderedEvent(ctx context.Context, evTime time.Time, user
 			Msg: fmt.Sprintf("Failed to set new %q event content: %s", builder.Type, err),
 		}
 	}
+	// Get the sender domain.
+	_, senderDomain, serr := r.Cfg.Matrix.SplitLocalID('@', builder.Sender)
+	if serr != nil {
+		return nil, &api.PerformError{
+			Msg: fmt.Sprintf("Failed to split user ID %q: %s", builder.Sender, err),
+		}
+	}
+	identity, err := r.Cfg.Matrix.SigningIdentityFor(senderDomain)
+	if err != nil {
+		return nil, &api.PerformError{
+			Msg: fmt.Sprintf("Failed to get signing identity for %q: %s", senderDomain, err),
+		}
+	}
 	var queryRes api.QueryLatestEventsAndStateResponse
-	headeredEvent, err := eventutil.QueryAndBuildEvent(ctx, &builder, r.Cfg.Matrix, evTime, r.URSAPI, &queryRes)
+	headeredEvent, err := eventutil.QueryAndBuildEvent(ctx, &builder, r.Cfg.Matrix, identity, evTime, r.URSAPI, &queryRes)
 	if err == eventutil.ErrRoomNoExists {
 		return nil, &api.PerformError{
 			Code: api.PerformErrorNoRoom,
@@ -686,7 +699,7 @@ func (r *Upgrader) sendHeaderedEvent(
 		Origin:       serverName,
 		SendAsServer: sendAsServer,
 	})
-	if err := api.SendInputRoomEvents(ctx, r.URSAPI, inputs, false); err != nil {
+	if err := api.SendInputRoomEvents(ctx, r.URSAPI, serverName, inputs, false); err != nil {
 		return &api.PerformError{
 			Msg: fmt.Sprintf("Failed to send new %q event to roomserver: %s", headeredEvent.Type(), err),
 		}

roomserver/internal/query/query.go

@@ -37,10 +37,10 @@ import (
 )
 
 type Queryer struct {
-	DB         storage.Database
-	Cache      caching.RoomServerCaches
-	ServerName gomatrixserverlib.ServerName
-	ServerACLs *acls.ServerACLs
+	DB                storage.Database
+	Cache             caching.RoomServerCaches
+	IsLocalServerName func(gomatrixserverlib.ServerName) bool
+	ServerACLs        *acls.ServerACLs
 }
 
 // QueryLatestEventsAndState implements api.RoomserverInternalAPI
@@ -392,7 +392,7 @@ func (r *Queryer) QueryServerJoinedToRoom(
 	}
 	response.RoomExists = true
 
-	if request.ServerName == r.ServerName || request.ServerName == "" {
+	if r.IsLocalServerName(request.ServerName) || request.ServerName == "" {
 		response.IsInRoom, err = r.DB.GetLocalServerInRoom(ctx, info.RoomNID)
 		if err != nil {
 			return fmt.Errorf("r.DB.GetLocalServerInRoom: %w", err)

roomserver/roomserver_test.go

@@ -44,7 +44,7 @@ func Test_SharedUsers(t *testing.T) {
 		// SetFederationAPI starts the room event input consumer
 		rsAPI.SetFederationAPI(nil, nil)
 		// Create the room
-		if err := api.SendEvents(ctx, rsAPI, api.KindNew, room.Events(), "test", "test", nil, false); err != nil {
+		if err := api.SendEvents(ctx, rsAPI, api.KindNew, room.Events(), "test", "test", "test", nil, false); err != nil {
 			t.Fatalf("failed to send events: %v", err)
 		}
 

setup/base/base.go

@@ -364,10 +364,10 @@ func (b *BaseDendrite) CreateClient() *gomatrixserverlib.Client {
 // CreateFederationClient creates a new federation client. Should only be called
 // once per component.
 func (b *BaseDendrite) CreateFederationClient() *gomatrixserverlib.FederationClient {
+	identities := b.Cfg.Global.SigningIdentities()
 	if b.Cfg.Global.DisableFederation {
 		return gomatrixserverlib.NewFederationClient(
-			b.Cfg.Global.ServerName, b.Cfg.Global.KeyID, b.Cfg.Global.PrivateKey,
-			gomatrixserverlib.WithTransport(noOpHTTPTransport),
+			identities, gomatrixserverlib.WithTransport(noOpHTTPTransport),
 		)
 	}
 	opts := []gomatrixserverlib.ClientOption{
@@ -379,8 +379,7 @@ func (b *BaseDendrite) CreateFederationClient() *gomatrixserverlib.FederationCli
 		opts = append(opts, gomatrixserverlib.WithDNSCache(b.DNSCache))
 	}
 	client := gomatrixserverlib.NewFederationClient(
-		b.Cfg.Global.ServerName, b.Cfg.Global.KeyID,
-		b.Cfg.Global.PrivateKey, opts...,
+		identities, opts...,
 	)
 	client.SetUserAgent(fmt.Sprintf("Dendrite/%s", internal.VersionString()))
 	return client

setup/config/config.go

@@ -231,6 +231,21 @@ func loadConfig(
 		return nil, err
 	}
 
+	for _, v := range c.Global.VirtualHosts {
+		if v.KeyValidityPeriod == 0 {
+			v.KeyValidityPeriod = c.Global.KeyValidityPeriod
+		}
+		if v.PrivateKeyPath == "" {
+			v.KeyID = c.Global.KeyID
+			v.PrivateKey = c.Global.PrivateKey
+			continue
+		}
+		privateKeyPath := absPath(basePath, v.PrivateKeyPath)
+		if v.KeyID, v.PrivateKey, err = LoadMatrixKey(privateKeyPath, readFile); err != nil {
+			return nil, err
+		}
+	}
+
 	for _, key := range c.Global.OldVerifyKeys {
 		switch {
 		case key.PrivateKeyPath != "":

setup/config/config_global.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"fmt"
 	"math/rand"
 	"strconv"
 	"strings"
@@ -15,7 +16,7 @@ type Global struct {
 	ServerName gomatrixserverlib.ServerName `yaml:"server_name"`
 
 	// The secondary server names, used for virtual hosting.
-	SecondaryServerNames []gomatrixserverlib.ServerName `yaml:"-"`
+	VirtualHosts []*VirtualHost `yaml:"virtual_hosts"`
 
 	// Path to the private key which will be used to sign requests and events.
 	PrivateKeyPath Path `yaml:"private_key"`
@@ -114,6 +115,10 @@ func (c *Global) Verify(configErrs *ConfigErrors, isMonolith bool) {
 	checkNotEmpty(configErrs, "global.server_name", string(c.ServerName))
 	checkNotEmpty(configErrs, "global.private_key", string(c.PrivateKeyPath))
 
+	for _, v := range c.VirtualHosts {
+		v.Verify(configErrs)
+	}
+
 	c.JetStream.Verify(configErrs, isMonolith)
 	c.Metrics.Verify(configErrs, isMonolith)
 	c.Sentry.Verify(configErrs, isMonolith)
@@ -127,14 +132,85 @@ func (c *Global) IsLocalServerName(serverName gomatrixserverlib.ServerName) bool
 	if c.ServerName == serverName {
 		return true
 	}
-	for _, secondaryName := range c.SecondaryServerNames {
-		if secondaryName == serverName {
+	for _, v := range c.VirtualHosts {
+		if v.ServerName == serverName {
 			return true
 		}
 	}
 	return false
 }
 
+func (c *Global) SplitLocalID(sigil byte, id string) (string, gomatrixserverlib.ServerName, error) {
+	u, s, err := gomatrixserverlib.SplitID(sigil, id)
+	if err != nil {
+		return u, s, err
+	}
+	if !c.IsLocalServerName(s) {
+		return u, s, fmt.Errorf("server name %q not known", s)
+	}
+	return u, s, nil
+}
+
+func (c *Global) SigningIdentityFor(serverName gomatrixserverlib.ServerName) (*gomatrixserverlib.SigningIdentity, error) {
+	for _, id := range c.SigningIdentities() {
+		if id.ServerName == serverName {
+			return id, nil
+		}
+	}
+	return nil, fmt.Errorf("no signing identity %q", serverName)
+}
+
+func (c *Global) SigningIdentities() []*gomatrixserverlib.SigningIdentity {
+	identities := make([]*gomatrixserverlib.SigningIdentity, 0, len(c.VirtualHosts)+1)
+	identities = append(identities, &gomatrixserverlib.SigningIdentity{
+		ServerName: c.ServerName,
+		KeyID:      c.KeyID,
+		PrivateKey: c.PrivateKey,
+	})
+	for _, v := range c.VirtualHosts {
+		identities = append(identities, v.SigningIdentity())
+	}
+	return identities
+}
+
+type VirtualHost struct {
+	// The server name of the virtual host.
+	ServerName gomatrixserverlib.ServerName `yaml:"server_name"`
+
+	// The key ID of the private key. If not specified, the default global key ID
+	// will be used instead.
+	KeyID gomatrixserverlib.KeyID `yaml:"key_id"`
+
+	// Path to the private key. If not specified, the default global private key
+	// will be used instead.
+	PrivateKeyPath Path `yaml:"private_key"`
+
+	// The private key itself.
+	PrivateKey ed25519.PrivateKey `yaml:"-"`
+
+	// How long a remote server can cache our server key for before requesting it again.
+	// Increasing this number will reduce the number of requests made by remote servers
+	// for our key, but increases the period a compromised key will be considered valid
+	// by remote servers.
+	// Defaults to 24 hours.
+	KeyValidityPeriod time.Duration `yaml:"key_validity_period"`
+
+	// Is registration enabled on this virtual host?
+	AllowRegistration bool `json:"allow_registration"`
+}
+
+func (v *VirtualHost) Verify(configErrs *ConfigErrors) {
+	checkNotEmpty(configErrs, "virtual_host.*.server_name", string(v.ServerName))
+}
+
+func (v *VirtualHost) SigningIdentity() *gomatrixserverlib.SigningIdentity {
+	return &gomatrixserverlib.SigningIdentity{
+		ServerName: v.ServerName,
+		KeyID:      v.KeyID,
+		PrivateKey: v.PrivateKey,
+	}
+}
+
 type OldVerifyKeys struct {
 	// Path to the private key.
 	PrivateKeyPath Path `yaml:"private_key"`

setup/mscs/msc2836/msc2836.go

@@ -397,7 +397,7 @@ func (rc *reqCtx) includeChildren(db Database, parentID string, limit int, recen
 		serversToQuery := rc.getServersForEventID(parentID)
 		var result *MSC2836EventRelationshipsResponse
 		for _, srv := range serversToQuery {
-			res, err := rc.fsAPI.MSC2836EventRelationships(rc.ctx, srv, gomatrixserverlib.MSC2836EventRelationshipsRequest{
+			res, err := rc.fsAPI.MSC2836EventRelationships(rc.ctx, rc.serverName, srv, gomatrixserverlib.MSC2836EventRelationshipsRequest{
 				EventID:     parentID,
 				Direction:   "down",
 				Limit:       100,
@@ -484,7 +484,7 @@ func walkThread(
 
 // MSC2836EventRelationships performs an /event_relationships request to a remote server
 func (rc *reqCtx) MSC2836EventRelationships(eventID string, srv gomatrixserverlib.ServerName, ver gomatrixserverlib.RoomVersion) (*MSC2836EventRelationshipsResponse, error) {
-	res, err := rc.fsAPI.MSC2836EventRelationships(rc.ctx, srv, gomatrixserverlib.MSC2836EventRelationshipsRequest{
+	res, err := rc.fsAPI.MSC2836EventRelationships(rc.ctx, rc.serverName, srv, gomatrixserverlib.MSC2836EventRelationshipsRequest{
 		EventID:     eventID,
 		DepthFirst:  rc.req.DepthFirst,
 		Direction:   rc.req.Direction,
@@ -665,7 +665,7 @@ func (rc *reqCtx) injectResponseToRoomserver(res *MSC2836EventRelationshipsRespo
 		})
 	}
 	// we've got the data by this point so use a background context
-	err := roomserver.SendInputRoomEvents(context.Background(), rc.rsAPI, ires, false)
+	err := roomserver.SendInputRoomEvents(context.Background(), rc.rsAPI, rc.serverName, ires, false)
 	if err != nil {
 		util.GetLogger(rc.ctx).WithError(err).Error("failed to inject MSC2836EventRelationshipsResponse into the roomserver")
 	}

setup/mscs/msc2946/msc2946.go

@@ -433,7 +433,7 @@ func (w *walker) federatedRoomInfo(roomID string, vias []string) *gomatrixserver
 		if serverName == string(w.thisServer) {
 			continue
 		}
-		res, err := w.fsAPI.MSC2946Spaces(ctx, gomatrixserverlib.ServerName(serverName), roomID, w.suggestedOnly)
+		res, err := w.fsAPI.MSC2946Spaces(ctx, w.thisServer, gomatrixserverlib.ServerName(serverName), roomID, w.suggestedOnly)
 		if err != nil {
 			util.GetLogger(w.ctx).WithError(err).Warnf("failed to call MSC2946Spaces on server %s", serverName)
 			continue

syncapi/consumers/keychange.go

@@ -28,22 +28,20 @@ import (
 	"github.com/matrix-org/dendrite/syncapi/storage"
 	"github.com/matrix-org/dendrite/syncapi/streams"
 	"github.com/matrix-org/dendrite/syncapi/types"
-	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/nats-io/nats.go"
 	"github.com/sirupsen/logrus"
 )
 
 // OutputKeyChangeEventConsumer consumes events that originated in the key server.
 type OutputKeyChangeEventConsumer struct {
-	ctx        context.Context
-	jetstream  nats.JetStreamContext
-	durable    string
-	topic      string
-	db         storage.Database
-	notifier   *notifier.Notifier
-	stream     streams.StreamProvider
-	serverName gomatrixserverlib.ServerName // our server name
-	rsAPI      roomserverAPI.SyncRoomserverAPI
+	ctx       context.Context
+	jetstream nats.JetStreamContext
+	durable   string
+	topic     string
+	db        storage.Database
+	notifier  *notifier.Notifier
+	stream    streams.StreamProvider
+	rsAPI     roomserverAPI.SyncRoomserverAPI
 }
 
 // NewOutputKeyChangeEventConsumer creates a new OutputKeyChangeEventConsumer.
@@ -59,15 +57,14 @@ func NewOutputKeyChangeEventConsumer(
 	stream streams.StreamProvider,
 ) *OutputKeyChangeEventConsumer {
 	s := &OutputKeyChangeEventConsumer{
-		ctx:        process.Context(),
-		jetstream:  js,
-		durable:    cfg.Matrix.JetStream.Durable("SyncAPIKeyChangeConsumer"),
-		topic:      topic,
-		db:         store,
-		serverName: cfg.Matrix.ServerName,
-		rsAPI:      rsAPI,
-		notifier:   notifier,
-		stream:     stream,
+		ctx:       process.Context(),
+		jetstream: js,
+		durable:   cfg.Matrix.JetStream.Durable("SyncAPIKeyChangeConsumer"),
+		topic:     topic,
+		db:        store,
+		rsAPI:     rsAPI,
+		notifier:  notifier,
+		stream:    stream,
 	}
 
 	return s

syncapi/consumers/receipts.go

@@ -34,14 +34,13 @@ import (
 
 // OutputReceiptEventConsumer consumes events that originated in the EDU server.
 type OutputReceiptEventConsumer struct {
-	ctx        context.Context
-	jetstream  nats.JetStreamContext
-	durable    string
-	topic      string
-	db         storage.Database
-	stream     streams.StreamProvider
-	notifier   *notifier.Notifier
-	serverName gomatrixserverlib.ServerName
+	ctx       context.Context
+	jetstream nats.JetStreamContext
+	durable   string
+	topic     string
+	db        storage.Database
+	stream    streams.StreamProvider
+	notifier  *notifier.Notifier
 }
 
 // NewOutputReceiptEventConsumer creates a new OutputReceiptEventConsumer.
@@ -55,14 +54,13 @@ func NewOutputReceiptEventConsumer(
 	stream streams.StreamProvider,
 ) *OutputReceiptEventConsumer {
 	return &OutputReceiptEventConsumer{
-		ctx:        process.Context(),
-		jetstream:  js,
-		topic:      cfg.Matrix.JetStream.Prefixed(jetstream.OutputReceiptEvent),
-		durable:    cfg.Matrix.JetStream.Durable("SyncAPIReceiptConsumer"),
-		db:         store,
-		notifier:   notifier,
-		stream:     stream,
-		serverName: cfg.Matrix.ServerName,
+		ctx:       process.Context(),
+		jetstream: js,
+		topic:     cfg.Matrix.JetStream.Prefixed(jetstream.OutputReceiptEvent),
+		durable:   cfg.Matrix.JetStream.Durable("SyncAPIReceiptConsumer"),
+		db:        store,
+		notifier:  notifier,
+		stream:    stream,
 	}
 }
 

syncapi/consumers/roomserver.go

@@ -364,11 +364,7 @@ func (s *OutputRoomEventConsumer) notifyJoinedPeeks(ctx context.Context, ev *gom
 	// TODO: check that it's a join and not a profile change (means unmarshalling prev_content)
 	if membership == gomatrixserverlib.Join {
 		// check it's a local join
-		_, domain, err := gomatrixserverlib.SplitID('@', *ev.StateKey())
-		if err != nil {
-			return sp, fmt.Errorf("gomatrixserverlib.SplitID: %w", err)
-		}
-		if domain != s.cfg.Matrix.ServerName {
+		if _, _, err := s.cfg.Matrix.SplitLocalID('@', *ev.StateKey()); err != nil {
 			return sp, nil
 		}
 
@@ -390,9 +386,7 @@ func (s *OutputRoomEventConsumer) onNewInviteEvent(
 	if msg.Event.StateKey() == nil {
 		return
 	}
-	if _, serverName, err := gomatrixserverlib.SplitID('@', *msg.Event.StateKey()); err != nil {
-		return
-	} else if serverName != s.cfg.Matrix.ServerName {
+	if _, _, err := s.cfg.Matrix.SplitLocalID('@', *msg.Event.StateKey()); err != nil {
 		return
 	}
 	pduPos, err := s.db.AddInviteEvent(ctx, msg.Event)

syncapi/consumers/sendtodevice.go

@@ -37,15 +37,15 @@ import (
 
 // OutputSendToDeviceEventConsumer consumes events that originated in the EDU server.
 type OutputSendToDeviceEventConsumer struct {
-	ctx        context.Context
-	jetstream  nats.JetStreamContext
-	durable    string
-	topic      string
-	db         storage.Database
-	keyAPI     keyapi.SyncKeyAPI
-	serverName gomatrixserverlib.ServerName // our server name
-	stream     streams.StreamProvider
-	notifier   *notifier.Notifier
+	ctx               context.Context
+	jetstream         nats.JetStreamContext
+	durable           string
+	topic             string
+	db                storage.Database
+	keyAPI            keyapi.SyncKeyAPI
+	isLocalServerName func(gomatrixserverlib.ServerName) bool
+	stream            streams.StreamProvider
+	notifier          *notifier.Notifier
 }
 
 // NewOutputSendToDeviceEventConsumer creates a new OutputSendToDeviceEventConsumer.
@@ -60,15 +60,15 @@ func NewOutputSendToDeviceEventConsumer(
 	stream streams.StreamProvider,
 ) *OutputSendToDeviceEventConsumer {
 	return &OutputSendToDeviceEventConsumer{
-		ctx:        process.Context(),
-		jetstream:  js,
-		topic:      cfg.Matrix.JetStream.Prefixed(jetstream.OutputSendToDeviceEvent),
-		durable:    cfg.Matrix.JetStream.Durable("SyncAPISendToDeviceConsumer"),
-		db:         store,
-		keyAPI:     keyAPI,
-		serverName: cfg.Matrix.ServerName,
-		notifier:   notifier,
-		stream:     stream,
+		ctx:               process.Context(),
+		jetstream:         js,
+		topic:             cfg.Matrix.JetStream.Prefixed(jetstream.OutputSendToDeviceEvent),
+		durable:           cfg.Matrix.JetStream.Durable("SyncAPISendToDeviceConsumer"),
+		db:                store,
+		keyAPI:            keyAPI,
+		isLocalServerName: cfg.Matrix.IsLocalServerName,
+		notifier:          notifier,
+		stream:            stream,
 	}
 }
 
@@ -89,7 +89,7 @@ func (s *OutputSendToDeviceEventConsumer) onMessage(ctx context.Context, msgs []
 		log.WithError(err).Errorf("send-to-device: failed to split user id, dropping message")
 		return true
 	}
-	if domain != s.serverName {
+	if !s.isLocalServerName(domain) {
 		log.Tracef("ignoring send-to-device event with destination %s", domain)
 		return true
 	}
@@ -114,7 +114,7 @@ func (s *OutputSendToDeviceEventConsumer) onMessage(ctx context.Context, msgs []
 	if output.Type == "m.room_key_request" {
 		requestingDeviceID := gjson.GetBytes(output.SendToDeviceEvent.Content, "requesting_device_id").Str
 		_, senderDomain, _ := gomatrixserverlib.SplitID('@', output.Sender)
-		if requestingDeviceID != "" && senderDomain != s.serverName {
+		if requestingDeviceID != "" && !s.isLocalServerName(senderDomain) {
 			// Mark the requesting device as stale, if we don't know about it.
 			if err = s.keyAPI.PerformMarkAsStaleIfNeeded(ctx, &keyapi.PerformMarkAsStaleRequest{
 				UserID: output.Sender, Domain: senderDomain, DeviceID: requestingDeviceID,

syncapi/routing/messages.go

@@ -528,6 +528,7 @@ func (r *messagesReq) backfill(roomID string, backwardsExtremities map[string][]
 		BackwardsExtremities: backwardsExtremities,
 		Limit:                limit,
 		ServerName:           r.cfg.Matrix.ServerName,
+		VirtualHost:          r.device.UserDomain(),
 	}, &res)
 	if err != nil {
 		return nil, fmt.Errorf("PerformBackfill failed: %w", err)

syncapi/syncapi_test.go

@@ -433,7 +433,7 @@ func testHistoryVisibility(t *testing.T, dbType test.DBType) {
 				beforeJoinBody := fmt.Sprintf("Before invite in a %s room", tc.historyVisibility)
 				beforeJoinEv := room.CreateAndInsert(t, alice, "m.room.message", map[string]interface{}{"body": beforeJoinBody})
 				eventsToSend := append(room.Events(), beforeJoinEv)
-				if err := api.SendEvents(ctx, rsAPI, api.KindNew, eventsToSend, "test", "test", nil, false); err != nil {
+				if err := api.SendEvents(ctx, rsAPI, api.KindNew, eventsToSend, "test", "test", "test", nil, false); err != nil {
 					t.Fatalf("failed to send events: %v", err)
 				}
 				syncUntil(t, base, aliceDev.AccessToken, false,
@@ -472,7 +472,7 @@ func testHistoryVisibility(t *testing.T, dbType test.DBType) {
 
 				eventsToSend = append([]*gomatrixserverlib.HeaderedEvent{}, inviteEv, afterInviteEv, joinEv, msgEv)
 
-				if err := api.SendEvents(ctx, rsAPI, api.KindNew, eventsToSend, "test", "test", nil, false); err != nil {
+				if err := api.SendEvents(ctx, rsAPI, api.KindNew, eventsToSend, "test", "test", "test", nil, false); err != nil {
 					t.Fatalf("failed to send events: %v", err)
 				}
 				syncUntil(t, base, aliceDev.AccessToken, false,