Browse Source
- trampoline node is the final recipient of MPP - each trampoline receives a bucket of HTLCs - if a HTLC from a bucket fails, wait for the entire bucket to fail - move trampoline route and onion code into trampoline modulepatch-4
ThomasV
4 years ago
4 changed files with 406 additions and 282 deletions
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import os |
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import bitstring |
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from .lnutil import LnFeatures |
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from .lnonion import calc_hops_data_for_payment, new_onion_packet |
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from .lnrouter import RouteEdge, TrampolineEdge, LNPaymentRoute, is_route_sane_to_use |
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from .lnutil import NoPathFound |
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from .logging import get_logger, Logger |
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_logger = get_logger(__name__) |
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# trampoline nodes are supposed to advertise their fee and cltv in node_update message |
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TRAMPOLINE_FEES = [ |
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{ |
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'fee_base_msat': 0, |
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'fee_proportional_millionths': 0, |
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'cltv_expiry_delta': 576, |
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}, |
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{ |
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'fee_base_msat': 1000, |
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'fee_proportional_millionths': 100, |
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'cltv_expiry_delta': 576, |
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}, |
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{ |
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'fee_base_msat': 3000, |
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'fee_proportional_millionths': 100, |
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'cltv_expiry_delta': 576, |
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}, |
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{ |
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'fee_base_msat': 5000, |
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'fee_proportional_millionths': 500, |
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'cltv_expiry_delta': 576, |
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}, |
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{ |
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'fee_base_msat': 7000, |
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'fee_proportional_millionths': 1000, |
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'cltv_expiry_delta': 576, |
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}, |
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{ |
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'fee_base_msat': 12000, |
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'fee_proportional_millionths': 3000, |
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'cltv_expiry_delta': 576, |
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}, |
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{ |
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'fee_base_msat': 100000, |
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'fee_proportional_millionths': 3000, |
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'cltv_expiry_delta': 576, |
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}, |
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] |
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def encode_routing_info(r_tags): |
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result = bitstring.BitArray() |
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for route in r_tags: |
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result.append(bitstring.pack('uint:8', len(route))) |
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for step in route: |
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pubkey, channel, feebase, feerate, cltv = step |
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result.append(bitstring.BitArray(pubkey) + bitstring.BitArray(channel) + bitstring.pack('intbe:32', feebase) + bitstring.pack('intbe:32', feerate) + bitstring.pack('intbe:16', cltv)) |
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return result.tobytes() |
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def create_trampoline_route( |
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amount_msat:int, |
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bucket_amount_msat:int, |
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min_cltv_expiry:int, |
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invoice_pubkey:bytes, |
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invoice_features:int, |
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trampoline_node_id, |
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r_tags, t_tags, |
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trampoline_fee_level, |
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trampoline2_list) -> LNPaymentRoute: |
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invoice_features = LnFeatures(invoice_features) |
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# We do not set trampoline_routing_opt in our invoices, because the spec is not ready |
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# Do not use t_tags if the flag is set, because we the format is not decided yet |
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if invoice_features.supports(LnFeatures.OPTION_TRAMPOLINE_ROUTING_OPT): |
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is_legacy = False |
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if len(r_tags) > 0 and len(r_tags[0]) == 1: |
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pubkey, scid, feebase, feerate, cltv = r_tags[0][0] |
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t_tag = pubkey, feebase, feerate, cltv |
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else: |
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t_tag = None |
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elif len(t_tags) > 0: |
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is_legacy = False |
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t_tag = t_tags[0] |
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else: |
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is_legacy = True |
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# fee level. the same fee is used for all trampolines |
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if trampoline_fee_level < len(TRAMPOLINE_FEES): |
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params = TRAMPOLINE_FEES[trampoline_fee_level] |
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else: |
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raise NoPathFound() |
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# add optional second trampoline |
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trampoline2 = None |
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if is_legacy: |
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for node_id in trampoline2_list: |
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if node_id != trampoline_node_id: |
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trampoline2 = node_id |
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break |
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# node_features is only used to determine is_tlv |
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trampoline_features = LnFeatures.VAR_ONION_OPT |
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# hop to trampoline |
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route = [] |
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# trampoline hop |
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route.append( |
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TrampolineEdge( |
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node_id=trampoline_node_id, |
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fee_base_msat=params['fee_base_msat'], |
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fee_proportional_millionths=params['fee_proportional_millionths'], |
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cltv_expiry_delta=params['cltv_expiry_delta'], |
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node_features=trampoline_features)) |
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if trampoline2: |
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route.append( |
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TrampolineEdge( |
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node_id=trampoline2, |
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fee_base_msat=params['fee_base_msat'], |
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fee_proportional_millionths=params['fee_proportional_millionths'], |
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cltv_expiry_delta=params['cltv_expiry_delta'], |
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node_features=trampoline_features)) |
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# add routing info |
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if is_legacy: |
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invoice_routing_info = encode_routing_info(r_tags) |
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route[-1].invoice_routing_info = invoice_routing_info |
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route[-1].invoice_features = invoice_features |
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else: |
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if t_tag: |
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pubkey, feebase, feerate, cltv = t_tag |
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if route[-1].node_id != pubkey: |
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route.append( |
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TrampolineEdge( |
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node_id=pubkey, |
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fee_base_msat=feebase, |
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fee_proportional_millionths=feerate, |
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cltv_expiry_delta=cltv, |
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node_features=trampoline_features)) |
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# Fake edge (not part of actual route, needed by calc_hops_data) |
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route.append( |
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TrampolineEdge( |
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node_id=invoice_pubkey, |
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fee_base_msat=0, |
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fee_proportional_millionths=0, |
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cltv_expiry_delta=0, |
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node_features=trampoline_features)) |
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# check that we can pay amount and fees |
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for edge in route[::-1]: |
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amount_msat += edge.fee_for_edge(amount_msat) |
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if not is_route_sane_to_use(route, amount_msat, min_cltv_expiry): |
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raise NoPathFound() |
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_logger.info(f'created route with trampoline: fee_level={trampoline_fee_level}, is legacy: {is_legacy}') |
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_logger.info(f'first trampoline: {trampoline_node_id.hex()}') |
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_logger.info(f'second trampoline: {trampoline2.hex() if trampoline2 else None}') |
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_logger.info(f'params: {params}') |
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return route |
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def create_trampoline_onion(route, amount_msat, final_cltv, total_msat, payment_hash, payment_secret): |
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# all edges are trampoline |
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hops_data, amount_msat, cltv = calc_hops_data_for_payment( |
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route, |
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amount_msat, |
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final_cltv, |
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total_msat=total_msat, |
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payment_secret=payment_secret) |
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# detect trampoline hops. |
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payment_path_pubkeys = [x.node_id for x in route] |
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num_hops = len(payment_path_pubkeys) |
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for i in range(num_hops-1): |
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route_edge = route[i] |
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next_edge = route[i+1] |
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assert route_edge.is_trampoline() |
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assert next_edge.is_trampoline() |
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hops_data[i].payload["outgoing_node_id"] = {"outgoing_node_id":next_edge.node_id} |
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if route_edge.invoice_features: |
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hops_data[i].payload["invoice_features"] = {"invoice_features":route_edge.invoice_features} |
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if route_edge.invoice_routing_info: |
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hops_data[i].payload["invoice_routing_info"] = {"invoice_routing_info":route_edge.invoice_routing_info} |
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# only for final, legacy |
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if i == num_hops - 2: |
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hops_data[i].payload["payment_data"] = { |
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"payment_secret":payment_secret, |
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"total_msat": total_msat, |
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} |
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trampoline_session_key = os.urandom(32) |
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trampoline_onion = new_onion_packet(payment_path_pubkeys, trampoline_session_key, hops_data, associated_data=payment_hash, trampoline=True) |
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return trampoline_onion, amount_msat, cltv |
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def create_trampoline_route_and_onion( |
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*, |
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amount_msat, |
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bucket_amount_msat, |
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min_cltv_expiry, |
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invoice_pubkey, |
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invoice_features, |
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node_id, |
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r_tags, t_tags, |
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payment_hash, |
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payment_secret, |
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local_height:int, |
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trampoline_fee_level, |
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trampoline2_list): |
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# create route for the trampoline_onion |
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trampoline_route = create_trampoline_route( |
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amount_msat, |
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bucket_amount_msat, |
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min_cltv_expiry, |
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invoice_pubkey, |
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invoice_features, |
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node_id, |
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r_tags, t_tags, |
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trampoline_fee_level, |
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trampoline2_list) |
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# compute onion and fees |
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final_cltv = local_height + min_cltv_expiry |
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trampoline_onion, bucket_amount_with_fees, bucket_cltv = create_trampoline_onion( |
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trampoline_route, |
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bucket_amount_msat, |
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final_cltv, |
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amount_msat, |
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payment_hash, |
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payment_secret) |
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bucket_cltv_delta = bucket_cltv - local_height |
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bucket_cltv_delta += trampoline_route[0].cltv_expiry_delta |
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# trampoline fee for this very trampoline |
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trampoline_fee = trampoline_route[0].fee_for_edge(bucket_amount_with_fees) |
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return trampoline_onion, trampoline_fee, bucket_amount_with_fees, bucket_cltv_delta |
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