AaronFiore/electrum
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Trampoline routing.

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- trampoline is enabled by default in config, to prevent download of `gossip_db`.
   (if disabled, `gossip_db` will be downloaded, regardless of the existence of channels)
 - if trampoline is enabled:
    - the wallet can only open channels with trampoline nodes
    - already-existing channels with non-trampoline nodes are frozen for sending.
 - there are two types of trampoline payments: legacy and end-to-end (e2e).
 - we decide to perform legacy or e2e based on the invoice:
    - we use trampoline_routing_opt in features to detect Eclair and Phoenix invoices
    - we use trampoline_routing_hints to detect Electrum invoices
 - when trying a legacy payment, we add a second trampoline to the path to preserve privacy.
   (we fall back to a single trampoline if the payment fails for all trampolines)
 - the trampoline list is hardcoded, it will remain so until `trampoline_routing_opt` feature flag is in INIT.
 - there are currently only two nodes in the hardcoded list, it would be nice to have more.
 - similar to Phoenix, we find the fee/cltv by trial-and-error.
    - if there is a second trampoline in the path, we use the same fee for both.
    - the final spec should add fee info in error messages, so we will be able to fine-tune fees
This commit is contained in:
ThomasV
2020-11-11 11:03:31 +01:00
parent f4fe80dfd1
commit ded449233e
19 changed files with 541 additions and 107 deletions
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11
electrum/lnaddr.py
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@@ -215,6 +215,10 @@ def lnencode(addr: 'LnAddr', privkey) -> str:
pubkey, channel, feebase, feerate, cltv = step
route.append(bitstring.BitArray(pubkey) + bitstring.BitArray(channel) + bitstring.pack('intbe:32', feebase) + bitstring.pack('intbe:32', feerate) + bitstring.pack('intbe:16', cltv))
data += tagged('r', route)
elif k == 't':
pubkey, feebase, feerate, cltv = v
route = bitstring.BitArray(pubkey) + bitstring.pack('intbe:32', feebase) + bitstring.pack('intbe:32', feerate) + bitstring.pack('intbe:16', cltv)
data += tagged('t', route)
elif k == 'f':
data += encode_fallback(v, addr.currency)
elif k == 'd':
@@ -409,6 +413,13 @@ def lndecode(invoice: str, *, verbose=False, expected_hrp=None) -> LnAddr:
s.read(32).uintbe,
s.read(16).uintbe))
addr.tags.append(('r',route))
elif tag == 't':
s = bitstring.ConstBitStream(tagdata)
e = (s.read(264).tobytes(),
s.read(32).uintbe,
s.read(32).uintbe,
s.read(16).uintbe)
addr.tags.append(('t', e))
elif tag == 'f':
fallback = parse_fallback(tagdata, addr.currency)
if fallback: