decode onion errors to failure message type

electrum/lnbase.py

@@ -31,7 +31,7 @@ from . import constants
 from . import transaction
 from .util import PrintError, bh2u, print_error, bfh
 from .transaction import opcodes, Transaction
-from .lnonion import new_onion_packet, OnionHopsDataSingle, OnionPerHop, decode_onion_error
+from .lnonion import new_onion_packet, OnionHopsDataSingle, OnionPerHop, decode_onion_error, ONION_FAILURE_CODE_MAP
 from .lnaddr import lndecode
 from .lnhtlc import UpdateAddHtlc, HTLCStateMachine, RevokeAndAck, SettleHtlc
 
@@ -817,25 +817,19 @@ class Peer(PrintError):
         route = self.attempted_route[key]
         failure_msg, sender_idx = decode_onion_error(payload["reason"], [x.node_id for x in route], self.secret_key)
         code = failure_msg.code
+        code_name = ONION_FAILURE_CODE_MAP.get(code, 'unknown_error!!')
         data = failure_msg.data
-        codes = []
-        if code & 0x8000:
-            codes += ["BADONION"]
-        if code & 0x4000:
-            codes += ["PERM"]
-        if code & 0x2000:
-            codes += ["NODE"]
-        if code & 0x1000:
-            codes += ["UPDATE"]
-        print("UPDATE_FAIL_HTLC", codes, code, data)
+        print("UPDATE_FAIL_HTLC", code_name, code, data)
         try:
             short_chan_id = route[sender_idx + 1].short_channel_id
         except IndexError:
             print("payment destination reported error")
         else:
+            # TODO this should depend on the error
+            # also, we need finer blacklisting (directed edges; nodes)
             self.network.path_finder.blacklist.add(short_chan_id)
 
-        self.update_fail_htlc[payload["channel_id"]].put_nowait("HTLC failure with code {} (categories {})".format(code, codes))
+        self.update_fail_htlc[payload["channel_id"]].put_nowait("HTLC failure with code {} ({})".format(code, code_name))
 
     @aiosafe
     async def pay(self, path, chan, amount_msat, payment_hash, pubkey_in_invoice, min_final_cltv_expiry):

electrum/lnonion.py

@@ -297,3 +297,35 @@ def get_failure_msg_from_onion_error(decrypted_error_packet: bytes) -> OnionRout
     failure_code = int.from_bytes(failure_msg[:2], byteorder='big')
     failure_data = failure_msg[2:]
     return OnionRoutingFailureMessage(failure_code, failure_data)
+
+
+ONION_FC_BADONION = BADONION = 0x8000
+ONION_FC_PERM     = PERM     = 0x4000
+ONION_FC_NODE     = NODE     = 0x2000
+ONION_FC_UPDATE   = UPDATE   = 0x1000
+ONION_FAILURE_CODE_MAP = {
+    PERM | 1 : 'invalid_realm',
+    NODE | 2 : 'temporary_node_failure',
+    PERM | NODE | 2 : 'permanent_node_failure',
+    PERM | NODE | 3 : 'required_node_feature_missing',
+    BADONION | PERM | 4 : 'invalid_onion_version',
+    BADONION | PERM | 5 : 'invalid_onion_hmac',
+    BADONION | PERM | 6 : 'invalid_onion_key',
+    UPDATE | 7 : 'temporary_channel_failure',
+    PERM | 8 : 'permanent_channel_failure',
+    PERM | 9 : 'required_channel_feature_missing',
+    PERM | 10 : 'unknown_next_peer',
+    UPDATE | 11 : 'amount_below_minimum',
+    UPDATE | 12 : 'fee_insufficient',
+    UPDATE | 13 : 'incorrect_cltv_expiry',
+    UPDATE | 14 : 'expiry_too_soon',
+    PERM | 15 : 'unknown_payment_hash',
+    PERM | 16 : 'incorrect_payment_amount',
+    17 : 'final_expiry_too_soon',
+    18 : 'final_incorrect_cltv_expiry',
+    19 : 'final_incorrect_htlc_amount',
+    UPDATE | 20 : 'channel_disabled',
+    21 : 'expiry_too_far',
+}
+# don't use these elsewhere, the names are ambiguous without context
+del BADONION; del PERM; del NODE; del UPDATE