lnpeer: restore "temp save orphan channel updates" functionality

needed to handle race where remote might send chan_upd too soon
(before we save the short channel id for the channel after it reaches funding locked)

electrum/channel_db.py

@@ -188,6 +188,15 @@ class Address(NamedTuple):
     port: int
     last_connected_date: int
 
+
+class CategorizedChannelUpdates(NamedTuple):
+    orphaned: List    # no channel announcement for channel update
+    expired: List     # update older than two weeks
+    deprecated: List  # update older than database entry
+    good: List        # good updates
+    to_delete: List   # database entries to delete
+
+
 create_channel_info = """
 CREATE TABLE IF NOT EXISTS channel_info (
 short_channel_id VARCHAR(64),
@@ -241,7 +250,7 @@ class ChannelDB(SqlDB):
         self._channel_updates_for_private_channels = {}  # type: Dict[Tuple[bytes, bytes], dict]
         self.ca_verifier = LNChannelVerifier(network, self)
         # initialized in load_data
-        self._channels = {}
+        self._channels = {}  # type: Dict[bytes, ChannelInfo]
         self._policies = {}
         self._nodes = {}
         self._addresses = defaultdict(set)
@@ -320,12 +329,12 @@ class ChannelDB(SqlDB):
         if old_policy.channel_flags != new_policy.channel_flags:
             self.logger.info(f'channel_flags: {old_policy.channel_flags} -> {new_policy.channel_flags}')
 
-    def add_channel_updates(self, payloads, max_age=None, verify=True):
-        orphaned = []      # no channel announcement for channel update
-        expired = []       # update older than two weeks
-        deprecated = []    # update older than database entry
-        good = []          # good updates
-        to_delete = []     # database entries to delete
+    def add_channel_updates(self, payloads, max_age=None, verify=True) -> CategorizedChannelUpdates:
+        orphaned = []
+        expired = []
+        deprecated = []
+        good = []
+        to_delete = []
         # filter orphaned and expired first
         known = []
         now = int(time.time())
@@ -333,11 +342,11 @@ class ChannelDB(SqlDB):
             short_channel_id = payload['short_channel_id']
             timestamp = int.from_bytes(payload['timestamp'], "big")
             if max_age and now - timestamp > max_age:
-                expired.append(short_channel_id)
+                expired.append(payload)
                 continue
             channel_info = self._channels.get(short_channel_id)
             if not channel_info:
-                orphaned.append(short_channel_id)
+                orphaned.append(payload)
                 continue
             flags = int.from_bytes(payload['channel_flags'], 'big')
             direction = flags & FLAG_DIRECTION
@@ -352,7 +361,7 @@ class ChannelDB(SqlDB):
             key = (start_node, short_channel_id)
             old_policy = self._policies.get(key)
             if old_policy and timestamp <= old_policy.timestamp:
-                deprecated.append(short_channel_id)
+                deprecated.append(payload)
                 continue
             good.append(payload)
             if verify:
@@ -362,11 +371,17 @@ class ChannelDB(SqlDB):
             self.save_policy(policy)
         #
         self.update_counts()
-        return orphaned, expired, deprecated, good, to_delete
+        return CategorizedChannelUpdates(
+            orphaned=orphaned,
+            expired=expired,
+            deprecated=deprecated,
+            good=good,
+            to_delete=to_delete,
+        )
 
     def add_channel_update(self, payload):
-        orphaned, expired, deprecated, good, to_delete = self.add_channel_updates([payload], verify=False)
-        assert len(good) == 1
+        categorized_chan_upds = self.add_channel_updates([payload], verify=False)
+        assert len(categorized_chan_upds.good) == 1
 
     def create_database(self):
         c = self.conn.cursor()

electrum/lnpeer.py

@@ -266,13 +266,22 @@ class Peer(Logger):
                 self.channel_db.add_node_announcement(node_anns_chunk)
             # channel updates
             for chan_upds_chunk in chunks(chan_upds, 1000):
-                orphaned, expired, deprecated, good, to_delete = self.channel_db.add_channel_updates(
+                categorized_chan_upds = self.channel_db.add_channel_updates(
                     chan_upds_chunk, max_age=self.network.lngossip.max_age)
+                orphaned = categorized_chan_upds.orphaned
                 if orphaned:
                     self.logger.info(f'adding {len(orphaned)} unknown channel ids')
                     await self.network.lngossip.add_new_ids(orphaned)
-                if good:
-                    self.logger.debug(f'on_channel_update: {len(good)}/{len(chan_upds_chunk)}')
+                    # Save (some bounded number of) orphan channel updates for later
+                    # as it might be for our own direct channel with this peer
+                    # (and we might not yet know the short channel id for that)
+                    for chan_upd_payload in orphaned:
+                        short_channel_id = chan_upd_payload['short_channel_id']
+                        self.orphan_channel_updates[short_channel_id] = chan_upd_payload
+                        while len(self.orphan_channel_updates) > 25:
+                            self.orphan_channel_updates.popitem(last=False)
+                if categorized_chan_upds.good:
+                    self.logger.debug(f'on_channel_update: {len(categorized_chan_upds.good)}/{len(chan_upds_chunk)}')
             # refresh gui
             if chan_anns or node_anns or chan_upds:
                 self.network.lngossip.refresh_gui()
@@ -1074,18 +1083,18 @@ class Peer(Logger):
             channel_update = (258).to_bytes(length=2, byteorder="big") + data[offset+2: offset+2+channel_update_len]
             message_type, payload = decode_msg(channel_update)
             payload['raw'] = channel_update
-            orphaned, expired, deprecated, good, to_delete = self.channel_db.add_channel_updates([payload])
+            categorized_chan_upds = self.channel_db.add_channel_updates([payload])
             blacklist = False
-            if good:
+            if categorized_chan_upds.good:
                 self.logger.info("applied channel update on our db")
-            elif orphaned:
+            elif categorized_chan_upds.orphaned:
                 # maybe it is a private channel (and data in invoice was outdated)
                 self.logger.info("maybe channel update is for private channel?")
                 start_node_id = route[sender_idx].node_id
                 self.channel_db.add_channel_update_for_private_channel(payload, start_node_id)
-            elif expired:
+            elif categorized_chan_upds.expired:
                 blacklist = True
-            elif deprecated:
+            elif categorized_chan_upds.deprecated:
                 self.logger.info(f'channel update is not more recent.')
                 blacklist = True
         else: