- `bitstring` started depending on `bitarray` in version 4.1 [0]
- that would mean one additional dependency for us (from yet another maintainer), which is not even pure python
- we only use bitstring for bolt11-parsing
- hence this PR rewrites the bolt11-parsing and removes `bitstring` as dependency
- note: I benchmarked lndecode using [1], and the new code performs better,
taking around 80% time needed for old code (when using bitstring 3.1.9, pure python).
Though the variance is quite large in both cases.
[0]: 95ee533ee4/release_notes.txt (L108)
[1]: d7597d96d0
- see comment in lnaddr.py
- Previously we used feature bit 50/51 for trampoline.
The spec subsequently defined fbit 50/51 as option_zeroconf, which
requires fbit 46/47 (option_scid_alias) to also be set.
We moved the non-standard trampoline fbit to a different int.
However, old wallets might have old invoices saved that set fbit 50/51
for trampoline, and those would not have the dependent bit set.
Invoices are parsed at wallet-open, so if the parser ran these checks,
those wallets could not be opened.
- note: we could potentially also run lnaddr.validate_and_compare_features
when saving new invoices into the wallet but this is not done here
We have supported sending to any witness version since Electrum 3.0, using
addresses as specified in BIP-0173 (bech32 encoding).
BIP-0350 makes a breaking change in address encoding, and recommends using
(and using only) a new encoding (bech32m) for sending to witness version 1
and later. The address encoding for currently in use witness v0 addresses
remains the same, as in BIP-0173; following the BIP-0350 spec.
closes https://github.com/spesmilo/electrum/issues/6949
related:
cd3885c0fb/bip-0350.mediawikihttps://github.com/bitcoin/bitcoin/pull/20861
- 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
Previously we failed to decode min_final_cltv_expiry properly if the highest bit was 1:
in practice, we could not pay invoices that had a value in [16-31] or [512-1023].
Many invoices use a value around 144, so this was simply unnoticed.
also update default value to follow BOLT change:
c5693d336d
Internally, we've been using an expiration of 0 to mean "never expires".
For LN invoices, BOLT-11 does not specify what an expiration of 0 means.
Other clients seem to treat it as "0 seconds" (i.e. already expired).
This means there is no way to create a BOLT-11 invoice that "never" expires.
For LN invoices,
- we now treat an expiration of 0, , as "0 seconds",
- when creating an invoice, if the user selected never, we will put 100 years as expiration
