Re-request Megolm sessions if they don't arrive on time

crypto.go

@@ -201,6 +201,15 @@ func (helper *CryptoHelper) WaitForSession(roomID id.RoomID, senderKey id.Sender
 	return helper.mach.WaitForSession(roomID, senderKey, sessionID, timeout)
 }
 
+func (helper *CryptoHelper) RequestSession(roomID id.RoomID, senderKey id.SenderKey, sessionID id.SessionID, userID id.UserID, deviceID id.DeviceID) {
+	err := helper.mach.SendRoomKeyRequest(roomID, senderKey, sessionID, "", map[id.UserID][]id.DeviceID{userID: {deviceID}})
+	if err != nil {
+		helper.log.Warnfln("Failed to send key request to %s/%s for %s in %s: %v", userID, deviceID, sessionID, roomID, err)
+	} else {
+		helper.log.Debugfln("Sent key request to %s/%s for %s in %s", userID, deviceID, sessionID, roomID)
+	}
+}
+
 func (helper *CryptoHelper) ResetSession(roomID id.RoomID) {
 	err := helper.mach.CryptoStore.RemoveOutboundGroupSession(roomID)
 	if err != nil {

go.mod

@@ -14,7 +14,7 @@ require (
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 	maunium.net/go/mauflag v1.0.0
 	maunium.net/go/maulogger/v2 v2.3.1
-	maunium.net/go/mautrix v0.10.3
+	maunium.net/go/mautrix v0.10.5-0.20211203161903-f556aff31562
 )
 
 require (

go.sum

@@ -221,5 +221,5 @@ maunium.net/go/mauflag v1.0.0 h1:YiaRc0tEI3toYtJMRIfjP+jklH45uDHtT80nUamyD4M=
 maunium.net/go/mauflag v1.0.0/go.mod h1:nLivPOpTpHnpzEh8jEdSL9UqO9+/KBJFmNRlwKfkPeA=
 maunium.net/go/maulogger/v2 v2.3.1 h1:fwBYJne0pHvJrrIPHK+TAPfyxxbBEz46oVGez2x0ODE=
 maunium.net/go/maulogger/v2 v2.3.1/go.mod h1:TYWy7wKwz/tIXTpsx8G3mZseIRiC5DoMxSZazOHy68A=
-maunium.net/go/mautrix v0.10.3 h1:TNRhlpXnYcvPEDo0tnAvLoewQ4Zc4mhFHU4k4AipsOc=
-maunium.net/go/mautrix v0.10.3/go.mod h1:k4Ng5oci83MEbqPL6KOjPdbU7f8v01KlMjR/zTQ+7mA=
+maunium.net/go/mautrix v0.10.5-0.20211203161903-f556aff31562 h1:SjfM0TBdClR/RIFPCY3Ufz+QCbvC/qwjiHzN/Z2JuaM=
+maunium.net/go/mautrix v0.10.5-0.20211203161903-f556aff31562/go.mod h1:k4Ng5oci83MEbqPL6KOjPdbU7f8v01KlMjR/zTQ+7mA=

main.go

@@ -194,6 +194,7 @@ type Crypto interface {
 	Decrypt(*event.Event) (*event.Event, error)
 	Encrypt(id.RoomID, event.Type, event.Content) (*event.EncryptedEventContent, error)
 	WaitForSession(id.RoomID, id.SenderKey, id.SessionID, time.Duration) bool
+	RequestSession(id.RoomID, id.SenderKey, id.SessionID, id.UserID, id.DeviceID)
 	ResetSession(id.RoomID)
 	Init() error
 	Start()

matrix.go

@@ -342,7 +342,7 @@ func (mx *MatrixHandler) HandleEncrypted(evt *event.Event) {
 			mx.log.Debugfln("Got session %s after waiting, trying to decrypt %s again", content.SessionID, evt.ID)
 			decrypted, err = mx.bridge.Crypto.Decrypt(evt)
 		} else {
-			mx.as.SendErrorMessageSendCheckpoint(evt, appservice.StepDecrypted, err, false)
+			mx.as.SendErrorMessageSendCheckpoint(evt, appservice.StepDecrypted, fmt.Errorf("didn't receive encryption keys"), false)
 			go mx.waitLongerForSession(evt)
 			return
 		}
@@ -360,12 +360,14 @@ func (mx *MatrixHandler) HandleEncrypted(evt *event.Event) {
 }
 
 func (mx *MatrixHandler) waitLongerForSession(evt *event.Event) {
-	const extendedTimeout = sessionWaitTimeout * 2
+	const extendedTimeout = sessionWaitTimeout * 3
 
 	content := evt.Content.AsEncrypted()
 	mx.log.Debugfln("Couldn't find session %s trying to decrypt %s, waiting %d more seconds...",
 		content.SessionID, evt.ID, int(extendedTimeout.Seconds()))
 
+	go mx.bridge.Crypto.RequestSession(evt.RoomID, content.SenderKey, content.SessionID, evt.Sender, content.DeviceID)
+
 	resp, err := mx.bridge.Bot.SendNotice(evt.RoomID, fmt.Sprintf(
 		"\u26a0 Your message was not bridged: the bridge hasn't received the decryption keys. "+
 			"The bridge will retry for %d seconds. If this error keeps happening, try restarting your client.",
@@ -388,11 +390,10 @@ func (mx *MatrixHandler) waitLongerForSession(evt *event.Event) {
 		mx.as.SendErrorMessageSendCheckpoint(evt, appservice.StepDecrypted, err, true)
 		update.Body = fmt.Sprintf("\u26a0 Your message was not bridged: %v", err)
 	} else {
-		errMsg := fmt.Sprintf("Didn't get %s, giving up on %s", content.SessionID, evt.ID)
-		mx.log.Debugfln(errMsg)
-		mx.as.SendErrorMessageSendCheckpoint(evt, appservice.StepDecrypted, fmt.Errorf(errMsg), true)
+		mx.log.Debugfln("Didn't get %s, giving up on %s", content.SessionID, evt.ID)
+		mx.as.SendErrorMessageSendCheckpoint(evt, appservice.StepDecrypted, fmt.Errorf("didn't receive encryption keys"), true)
 		update.Body = "\u26a0 Your message was not bridged: the bridge hasn't received the decryption keys. " +
-			"If this keeps happening, try restarting your client."
+			"If this error keeps happening, try restarting your client."
 	}
 
 	newContent := update