onion_message: generalize get_blinded_reply_paths to get_blinded_paths_to_me

Author: accumulator

electrum/onion_message.py

@@ -59,6 +59,7 @@ def now():
 
 
 REQUEST_REPLY_PATHS_MAX = 3
+PAYMENT_PATHS_MAX = 3
 
 
 class NoRouteFound(Exception):
@@ -364,33 +365,53 @@ def get_blinded_reply_paths(
         max_paths: int = REQUEST_REPLY_PATHS_MAX,
         preferred_node_id: bytes = None
 ) -> Sequence[dict]:
-    """construct a list of blinded reply_paths.
+    """construct a list of blinded reply-paths for onion message.
+    """
+    mydata = {'path_id': {'data': path_id}}  # same path_id used in every reply path
+    return get_blinded_paths_to_me(lnwallet, mydata, max_paths=max_paths,
+                                   preferred_node_id=preferred_node_id, onion_message=True)
+
+
+def get_blinded_paths_to_me(
+        lnwallet: 'LNWallet',
+        final_recipient_data: dict = {},
+        *,
+        max_paths: int = PAYMENT_PATHS_MAX,
+        preferred_node_id: bytes = None,
+        onion_message: bool = False
+) -> Sequence[dict]:
+    """construct a list of blinded paths.
        current logic:
-       - uses current onion_message capable channel peers if exist
-       - otherwise, uses current onion_message capable peers
+       - uses channels peers if not onion_message
+       - uses current onion_message capable channel peers if exist and if onion_message
+       - otherwise, uses current onion_message capable peers if onion_message
        - prefers preferred_node_id if given
-       - reply_path introduction points are direct peers only (TODO: longer reply paths)"""
+       - reply_path introduction points are direct peers only (TODO: longer paths)"""
     # TODO: build longer paths and/or add dummy hops to increase privacy
     my_active_channels = [chan for chan in lnwallet.channels.values() if chan.is_active()]
-    my_onionmsg_channels = [chan for chan in my_active_channels if lnwallet.peers.get(chan.node_id) and
-                            lnwallet.peers.get(chan.node_id).their_features.supports(LnFeatures.OPTION_ONION_MESSAGE_OPT)]
-    my_onionmsg_peers = [peer for peer in lnwallet.peers.values() if peer.their_features.supports(LnFeatures.OPTION_ONION_MESSAGE_OPT)]
+    my_channels = my_active_channels
+    if onion_message:
+        my_channels = [chan for chan in my_active_channels if lnwallet.peers.get(chan.node_id) and
+                       lnwallet.peers.get(chan.node_id).their_features.supports(LnFeatures.OPTION_ONION_MESSAGE_OPT)]
 
     result = []
     mynodeid = lnwallet.node_keypair.pubkey
-    mydata = {'path_id': {'data': path_id}}  # same path_id used in every reply path
-    if len(my_onionmsg_channels):
+    if len(my_channels):
         # randomize list, but prefer preferred_node_id
-        rchans = sorted(my_onionmsg_channels, key=lambda x: random() if x.node_id != preferred_node_id else 0)
+        rchans = sorted(my_channels, key=lambda x: random() if x.node_id != preferred_node_id else 0)
         for chan in rchans[:max_paths]:
-            blinded_path = create_blinded_path(os.urandom(32), [chan.node_id, mynodeid], mydata)
-            result.append(blinded_path)
-    elif len(my_onionmsg_peers):
-        # randomize list, but prefer preferred_node_id
-        rpeers = sorted(my_onionmsg_peers, key=lambda x: random() if x.pubkey != preferred_node_id else 0)
-        for peer in rpeers[:max_paths]:
-            blinded_path = create_blinded_path(os.urandom(32), [peer.pubkey, mynodeid], mydata)
+            blinded_path = create_blinded_path(os.urandom(32), [chan.node_id, mynodeid], final_recipient_data)
             result.append(blinded_path)
+    elif onion_message:
+        # we can use peers even without channels for onion messages
+        my_onionmsg_peers = [peer for peer in lnwallet.peers.values() if
+                             peer.their_features.supports(LnFeatures.OPTION_ONION_MESSAGE_OPT)]
+        if len(my_onionmsg_peers):
+            # randomize list, but prefer preferred_node_id
+            rpeers = sorted(my_onionmsg_peers, key=lambda x: random() if x.pubkey != preferred_node_id else 0)
+            for peer in rpeers[:max_paths]:
+                blinded_path = create_blinded_path(os.urandom(32), [peer.pubkey, mynodeid], final_recipient_data)
+                result.append(blinded_path)
 
     return result
 
@@ -645,10 +666,15 @@ def on_onion_message_received_unsolicited(self, recipient_data: dict, payload: d
         # e.g. via a decorator, something like
         # @onion_message_request_handler(payload_key='invoice_request') for BOLT12 invoice requests.
 
-        if 'message' not in payload:
+        if 'message' not in payload and 'invoice_request' not in payload:
             self.logger.error('Unsupported onion message payload')
             return
 
+        if 'invoice_request' in payload:
+            self.lnwallet.on_bolt12_invoice_request(recipient_data, payload)
+            return
+
+        # log 'message' payload
         if 'text' not in payload['message'] or not isinstance(payload['message']['text'], bytes):
             self.logger.error('Malformed \'message\' payload')
             return