ln gossip: don't put own channels into db; always pass them to fn calls

Previously we would put fake chan announcement and fake outgoing chan upd
for own channels into db (to make path finding work). See Peer.add_own_channel().
Now, instead of above, we pass a "my_channels" param to the relevant ChannelDB methods.

electrum/channel_db.py

@@ -39,9 +39,11 @@ from .util import bh2u, profiler, get_headers_dir, bfh, is_ip_address, list_enab
 from .logging import Logger
 from .lnutil import LN_GLOBAL_FEATURES_KNOWN_SET, LNPeerAddr, format_short_channel_id, ShortChannelID
 from .lnverifier import LNChannelVerifier, verify_sig_for_channel_update
+from .lnmsg import decode_msg
 
 if TYPE_CHECKING:
     from .network import Network
+    from .lnchannel import Channel
 
 
 class UnknownEvenFeatureBits(Exception): pass
@@ -63,7 +65,7 @@ class ChannelInfo(NamedTuple):
     capacity_sat: Optional[int]
 
     @staticmethod
-    def from_msg(payload):
+    def from_msg(payload: dict) -> 'ChannelInfo':
         features = int.from_bytes(payload['features'], 'big')
         validate_features(features)
         channel_id = payload['short_channel_id']
@@ -78,6 +80,11 @@ class ChannelInfo(NamedTuple):
             capacity_sat = capacity_sat
         )
 
+    @staticmethod
+    def from_raw_msg(raw: bytes) -> 'ChannelInfo':
+        payload_dict = decode_msg(raw)[1]
+        return ChannelInfo.from_msg(payload_dict)
+
 
 class Policy(NamedTuple):
     key: bytes
@@ -91,7 +98,7 @@ class Policy(NamedTuple):
     timestamp: int
 
     @staticmethod
-    def from_msg(payload):
+    def from_msg(payload: dict) -> 'Policy':
         return Policy(
             key                         = payload['short_channel_id'] + payload['start_node'],
             cltv_expiry_delta           = int.from_bytes(payload['cltv_expiry_delta'], "big"),
@@ -248,11 +255,11 @@ class ChannelDB(SqlDB):
         self.ca_verifier = LNChannelVerifier(network, self)
         # initialized in load_data
         self._channels = {}  # type: Dict[bytes, ChannelInfo]
-        self._policies = {}
+        self._policies = {}  # type: Dict[Tuple[bytes, bytes], Policy]  # (node_id, scid) -> Policy
         self._nodes = {}
         # node_id -> (host, port, ts)
         self._addresses = defaultdict(set)  # type: Dict[bytes, Set[Tuple[str, int, int]]]
-        self._channels_for_node = defaultdict(set)
+        self._channels_for_node = defaultdict(set)  # type: Dict[bytes, Set[ShortChannelID]]
         self.data_loaded = asyncio.Event()
         self.network = network # only for callback
 
@@ -495,17 +502,6 @@ class ChannelDB(SqlDB):
         self.logger.debug("on_node_announcement: %d/%d"%(len(new_nodes), len(msg_payloads)))
         self.update_counts()
 
-    def get_routing_policy_for_channel(self, start_node_id: bytes,
-                                       short_channel_id: bytes) -> Optional[Policy]:
-        if not start_node_id or not short_channel_id: return None
-        channel_info = self.get_channel_info(short_channel_id)
-        if channel_info is not None:
-            return self.get_policy_for_node(short_channel_id, start_node_id)
-        msg = self._channel_updates_for_private_channels.get((start_node_id, short_channel_id))
-        if not msg:
-            return None
-        return Policy.from_msg(msg) # won't actually be written to DB
-
     def get_old_policies(self, delta):
         now = int(time.time())
         return list(k for k, v in list(self._policies.items()) if v.timestamp <= now - delta)
@@ -587,12 +583,56 @@ class ChannelDB(SqlDB):
                 out.add(short_channel_id)
         self.logger.info(f'semi-orphaned: {len(out)}')
 
-    def get_policy_for_node(self, short_channel_id: bytes, node_id: bytes) -> Optional['Policy']:
-        return self._policies.get((node_id, short_channel_id))
+    def get_policy_for_node(self, short_channel_id: bytes, node_id: bytes, *,
+                            my_channels: Dict[ShortChannelID, 'Channel'] = None) -> Optional['Policy']:
+        channel_info = self.get_channel_info(short_channel_id)
+        if channel_info is not None:  # publicly announced channel
+            policy = self._policies.get((node_id, short_channel_id))
+            if policy:
+                return policy
+        else:  # private channel
+            chan_upd_dict = self._channel_updates_for_private_channels.get((node_id, short_channel_id))
+            if chan_upd_dict:
+                return Policy.from_msg(chan_upd_dict)
+        # check if it's one of our own channels
+        if not my_channels:
+            return
+        chan = my_channels.get(short_channel_id)  # type: Optional[Channel]
+        if not chan:
+            return
+        if node_id == chan.node_id:  # incoming direction (to us)
+            remote_update_raw = chan.get_remote_update()
+            if not remote_update_raw:
+                return
+            now = int(time.time())
+            remote_update_decoded = decode_msg(remote_update_raw)[1]
+            remote_update_decoded['timestamp'] = now.to_bytes(4, byteorder="big")
+            remote_update_decoded['start_node'] = node_id
+            return Policy.from_msg(remote_update_decoded)
+        elif node_id == chan.get_local_pubkey():  # outgoing direction (from us)
+            local_update_decoded = decode_msg(chan.get_outgoing_gossip_channel_update())[1]
+            local_update_decoded['start_node'] = node_id
+            return Policy.from_msg(local_update_decoded)
 
-    def get_channel_info(self, channel_id: bytes) -> ChannelInfo:
-        return self._channels.get(channel_id)
+    def get_channel_info(self, short_channel_id: bytes, *,
+                         my_channels: Dict[ShortChannelID, 'Channel'] = None) -> Optional[ChannelInfo]:
+        ret = self._channels.get(short_channel_id)
+        if ret:
+            return ret
+        # check if it's one of our own channels
+        if not my_channels:
+            return
+        chan = my_channels.get(short_channel_id)  # type: Optional[Channel]
+        ci = ChannelInfo.from_raw_msg(chan.construct_channel_announcement_without_sigs())
+        return ci._replace(capacity_sat=chan.constraints.capacity)
 
-    def get_channels_for_node(self, node_id) -> Set[bytes]:
-        """Returns the set of channels that have node_id as one of the endpoints."""
-        return self._channels_for_node.get(node_id) or set()
+    def get_channels_for_node(self, node_id: bytes, *,
+                              my_channels: Dict[ShortChannelID, 'Channel'] = None) -> Set[bytes]:
+        """Returns the set of short channel IDs where node_id is one of the channel participants."""
+        relevant_channels = self._channels_for_node.get(node_id) or set()
+        relevant_channels = set(relevant_channels)  # copy
+        # add our own channels  # TODO maybe slow?
+        for chan in (my_channels.values() or []):
+            if node_id in (chan.node_id, chan.get_local_pubkey()):
+                relevant_channels.add(chan.short_channel_id)
+        return relevant_channels