fix trampoline forwarding: add_received_htlc must be indexed by payment_secret

electrum/lnpeer.py

@@ -1536,13 +1536,14 @@ class Peer(Logger):
             # TODO fail here if invoice has set PAYMENT_SECRET_REQ
             payment_secret_from_onion = None
 
-        mpp_status = self.lnworker.add_received_htlc(chan.short_channel_id, htlc, total_msat)
-        if mpp_status is None:
-            return None, None
-        if mpp_status is False:
-            log_fail_reason(f"MPP_TIMEOUT")
-            raise OnionRoutingFailure(code=OnionFailureCode.MPP_TIMEOUT, data=b'')
-        assert mpp_status is True
+        if total_msat > amt_to_forward:
+            mpp_status = self.lnworker.add_received_htlc(payment_secret_from_onion, chan.short_channel_id, htlc, total_msat)
+            if mpp_status is None:
+                return None, None
+            if mpp_status is False:
+                log_fail_reason(f"MPP_TIMEOUT")
+                raise OnionRoutingFailure(code=OnionFailureCode.MPP_TIMEOUT, data=b'')
+            assert mpp_status is True
 
         # if there is a trampoline_onion, maybe_fulfill_htlc will be called again
         if processed_onion.trampoline_onion_packet:

electrum/lnworker.py

@@ -1594,28 +1594,33 @@ class LNWallet(LNWorker):
             self.payments[key] = info.amount_msat, info.direction, info.status
         self.wallet.save_db()
 
-    def add_received_htlc(self, short_channel_id, htlc: UpdateAddHtlc, expected_msat: int) -> Optional[bool]:
+    def add_received_htlc(self, payment_secret, short_channel_id, htlc: UpdateAddHtlc, expected_msat: int) -> Optional[bool]:
         """ return MPP status: True (accepted), False (expired) or None """
         payment_hash = htlc.payment_hash
-        is_accepted = (self.get_payment_status(payment_hash) == PR_PAID)
-        is_expired, htlc_set = self.received_htlcs.get(payment_hash, (False, set()))
+        is_expired, is_accepted, htlc_set = self.received_htlcs.get(payment_secret, (False, False, set()))
+        if self.get_payment_status(payment_hash) == PR_PAID:
+            # payment_status is persisted
+            is_accepted = True
+            is_expired = False
         key = (short_channel_id, htlc)
         if key not in htlc_set:
             htlc_set.add(key)
         if not is_accepted and not is_expired:
             total = sum([_htlc.amount_msat for scid, _htlc in htlc_set])
             first_timestamp = min([_htlc.timestamp for scid, _htlc in htlc_set])
-            is_expired = time.time() - first_timestamp > MPP_EXPIRY
-            if not is_expired and total == expected_msat:
+            if time.time() - first_timestamp > MPP_EXPIRY:
+                is_expired = True
+            elif total == expected_msat:
                 is_accepted = True
-                self.set_payment_status(payment_hash, PR_PAID)
-                util.trigger_callback('request_status', self.wallet, payment_hash.hex(), PR_PAID)
+                if self.get_payment_info(payment_hash) is not None:
+                    self.set_payment_status(payment_hash, PR_PAID)
+                    util.trigger_callback('request_status', self.wallet, payment_hash.hex(), PR_PAID)
         if is_accepted or is_expired:
             htlc_set.remove(key)
         if len(htlc_set) > 0:
-            self.received_htlcs[payment_hash] = is_expired, htlc_set
-        elif payment_hash in self.received_htlcs:
-            self.received_htlcs.pop(payment_hash)
+            self.received_htlcs[payment_secret] = is_expired, is_accepted, htlc_set
+        elif payment_secret in self.received_htlcs:
+            self.received_htlcs.pop(payment_secret)
         return True if is_accepted else (False if is_expired else None)
 
     def get_payment_status(self, payment_hash):