aljaz/plugins
1
0
Fork 0
mirror of https://github.com/aljazceru/plugins.git synced 2026-01-05 14:24:21 +01:00
Code Issues Packages Projects Releases Wiki Activity

rebalance: round HTLC fees up

Browse Source 
BOLT#7 requires that nodes "SHOULD accept HTLCs that pay a fee equal to or greater than:
fee_base_msat + ( amount_to_forward * fee_proportional_millionths / 1000000 )".

The code in rebalance.py:setup_routing_fees was not strictly meeting the above requirement, as it was using truncating integer division to calculate the proportional part of the fee, which typically results in a fee that is strictly less than the theoretical, infinite-precision, required fee. Some node implementations may allow rounding down here, but some do not, resulting in sporadic WIRE_FEE_INSUFFICIENT errors.

This commit changes the fee calculation in setup_routing_fees so that it always rounds up to the next whole millisatoshi, thereby eliminating many WIRE_FEE_INSUFFICIENT errors and improving the success rate of the rebalance command.
This commit is contained in:
Matt Whitlock
2019-08-18 13:38:37 -04:00
committed by Christian Decker
parent 9e25aad3d1
commit 477bdd8f61
1 changed files with 2 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
rebalance/rebalance.py
View File

@@ -15,7 +15,8 @@ def setup_routing_fees(plugin, route, msatoshi):
channels = plugin.rpc.listchannels(r['channel'])
ch = next(c for c in channels.get('channels') if c['destination'] == r['id'])
fee = Millisatoshi(ch['base_fee_millisatoshi'])
fee += msatoshi * ch['fee_per_millionth'] // 10**6
# BOLT #7 requires fee >= fee_base_msat + ( amount_to_forward * fee_proportional_millionths / 1000000 )
fee += (msatoshi * ch['fee_per_millionth'] + 999_999) // 1_000_000 # integer math trick to round up
msatoshi += fee
delay += ch['delay']