partial merge 2: f321x's "lightning: refactor htlc switch"

split-off from spesmilo#10230

Merge commit '286fc4b86e4d23cb9af15b9061b3d709e7592bcb'

Author: SomberNight

electrum/commands.py

@@ -68,7 +68,7 @@
 )
 from .address_synchronizer import TX_HEIGHT_LOCAL
 from .mnemonic import Mnemonic
-from .lnutil import (channel_id_from_funding_tx, LnFeatures, SENT, MIN_FINAL_CLTV_DELTA_FOR_INVOICE,
+from .lnutil import (channel_id_from_funding_tx, LnFeatures, SENT, MIN_FINAL_CLTV_DELTA_ACCEPTED,
                      PaymentFeeBudget, NBLOCK_CLTV_DELTA_TOO_FAR_INTO_FUTURE)
 from .plugin import run_hook, DeviceMgr, Plugins
 from .version import ELECTRUM_VERSION
@@ -1382,7 +1382,7 @@ async def add_hold_invoice(
             amount: Optional[Decimal] = None,
             memo: str = "",
             expiry: int = 3600,
-            min_final_cltv_expiry_delta: int = MIN_FINAL_CLTV_DELTA_FOR_INVOICE * 2,
+            min_final_cltv_expiry_delta: int = MIN_FINAL_CLTV_DELTA_ACCEPTED * 2,
             wallet: Abstract_Wallet = None
     ) -> dict:
         """
@@ -1399,24 +1399,24 @@ async def add_hold_invoice(
         assert payment_hash not in wallet.lnworker.payment_info, "Payment hash already used!"
         assert payment_hash not in wallet.lnworker.dont_settle_htlcs, "Payment hash already used!"
         assert wallet.lnworker.get_preimage(bfh(payment_hash)) is None, "Already got a preimage for this payment hash!"
-        assert MIN_FINAL_CLTV_DELTA_FOR_INVOICE < min_final_cltv_expiry_delta < 576, "Use a sane min_final_cltv_expiry_delta value"
+        assert MIN_FINAL_CLTV_DELTA_ACCEPTED < min_final_cltv_expiry_delta < 576, "Use a sane min_final_cltv_expiry_delta value"
         amount = amount if amount and satoshis(amount) > 0 else None  # make amount either >0 or None
         inbound_capacity = wallet.lnworker.num_sats_can_receive()
         assert inbound_capacity > satoshis(amount or 0), \
             f"Not enough inbound capacity [{inbound_capacity} sat] to receive this payment"
 
+        wallet.lnworker.add_payment_info_for_hold_invoice(
+            bfh(payment_hash),
+            lightning_amount_sat=satoshis(amount) if amount else None,
+            min_final_cltv_delta=min_final_cltv_expiry_delta,
+            exp_delay=expiry,
+        )
+        info = wallet.lnworker.get_payment_info(bfh(payment_hash))
         lnaddr, invoice = wallet.lnworker.get_bolt11_invoice(
-            payment_hash=bfh(payment_hash),
-            amount_msat=satoshis(amount) * 1000 if amount else None,
+            payment_info=info,
             message=memo,
-            expiry=expiry,
-            min_final_cltv_expiry_delta=min_final_cltv_expiry_delta,
             fallback_address=None
         )
-        wallet.lnworker.add_payment_info_for_hold_invoice(
-            bfh(payment_hash),
-            satoshis(amount) if amount else None,
-        )
         wallet.lnworker.dont_settle_htlcs[payment_hash] = None
         wallet.set_label(payment_hash, memo)
         result = {

electrum/gui/qt/main_window.py

@@ -2758,7 +2758,7 @@ def warning_callback() -> Optional[str]:
         self.closing_warning_callbacks.append(warning_callback)
 
     def _check_ongoing_force_closures(self) -> Optional[str]:
-        from electrum.lnutil import MIN_FINAL_CLTV_DELTA_FOR_INVOICE
+        from electrum.lnutil import MIN_FINAL_CLTV_DELTA_ACCEPTED
         if not self.wallet.has_lightning():
             return None
         if not self.network:
@@ -2767,7 +2767,7 @@ def _check_ongoing_force_closures(self) -> Optional[str]:
         if not force_closes:
             return
         # fixme: this is inaccurate, we need local_height - cltv_of_htlc
-        cltv_delta = MIN_FINAL_CLTV_DELTA_FOR_INVOICE
+        cltv_delta = MIN_FINAL_CLTV_DELTA_ACCEPTED
         msg = '\n\n'.join([
             _("Pending channel force-close"),
             messages.MSG_FORCE_CLOSE_WARNING.format(cltv_delta),

electrum/lnpeer.py

@@ -505,9 +505,10 @@ class LNProtocolWarning(Exception):
 # the minimum cltv_expiry accepted for newly received HTLCs
 # note: when changing, consider Blockchain.is_tip_stale()
 MIN_FINAL_CLTV_DELTA_ACCEPTED = 144
-# set it a tiny bit higher for invoices as blocks could get mined
-# during forward path of payment
-MIN_FINAL_CLTV_DELTA_FOR_INVOICE = MIN_FINAL_CLTV_DELTA_ACCEPTED + 3
+
+# buffer added to min_final_cltv_delta of created bolt11 invoices to make verifying the cltv delta
+# of incoming payment htlcs reliable even if some blocks have been mined during forwarding
+MIN_FINAL_CLTV_DELTA_BUFFER_INVOICE = 3
 
 # the deadline for offered HTLCs:
 # the deadline after which the channel has to be failed and timed out on-chain