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Fee reserve for lightning backends (#557)

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* preparing fees

* fee_limit_msat

* await resp result

* clightning

* fix tests

* fix test

* add fee to test

* mypy

* invoice_status

* checking id fix

* fee reserve error message

* only for external payments
This commit is contained in:
calle
2022-03-16 07:20:15 +01:00
committed by GitHub
parent 911fe92e03
commit 0f97f8f18b
15 changed files with 129 additions and 84 deletions
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lnbits/core/services.py
+23 -24
View File
@@ -85,18 +85,17 @@ async def pay_invoice(
description: str = "",
conn: Optional[Connection] = None,
) -> str:
invoice = bolt11.decode(payment_request)
fee_reserve_msat = fee_reserve(invoice.amount_msat)
async with (db.reuse_conn(conn) if conn else db.connect()) as conn:
temp_id = f"temp_{urlsafe_short_hash()}"
internal_id = f"internal_{urlsafe_short_hash()}"
invoice = bolt11.decode(payment_request)
if invoice.amount_msat == 0:
raise ValueError("Amountless invoices not supported.")
if max_sat and invoice.amount_msat > max_sat * 1000:
raise ValueError("Amount in invoice is too high.")
wallet = await get_wallet(wallet_id, conn=conn)
# put all parameters that don't change here
PaymentKwargs = TypedDict(
"PaymentKwargs",
@@ -134,26 +133,20 @@ async def pay_invoice(
# the balance is enough in the next step
await create_payment(
checking_id=temp_id,
fee=-fee_reserve(invoice.amount_msat),
fee=-fee_reserve_msat,
conn=conn,
**payment_kwargs,
)
# do the balance check if internal payment
if internal_checking_id:
wallet = await get_wallet(wallet_id, conn=conn)
assert wallet
if wallet.balance_msat < 0:
raise PermissionError("Insufficient balance.")
# do the balance check if external payment
else:
if invoice.amount_msat > wallet.balance_msat - (
wallet.balance_msat / 100 * 2
):
raise PermissionError(
"LNbits requires you keep at least 2% reserve to cover potential routing fees."
# do the balance check
wallet = await get_wallet(wallet_id, conn=conn)
assert wallet
if wallet.balance_msat < 0:
if not internal_checking_id and wallet.balance_msat > -fee_reserve_msat:
raise PaymentFailure(
f"You must reserve at least 1% ({round(fee_reserve_msat/1000)} sat) to cover potential routing fees."
)
raise PermissionError("Insufficient balance.")
if internal_checking_id:
# mark the invoice from the other side as not pending anymore
@@ -171,7 +164,9 @@ async def pay_invoice(
await internal_invoice_queue.put(internal_checking_id)
else:
# actually pay the external invoice
payment: PaymentResponse = await WALLET.pay_invoice(payment_request)
payment: PaymentResponse = await WALLET.pay_invoice(
payment_request, fee_reserve_msat
)
if payment.checking_id:
async with db.connect() as conn:
await create_payment(
@@ -286,12 +281,12 @@ async def perform_lnurlauth(
sign_len = 6 + r_len + s_len
signature = BytesIO()
signature.write(0x30 .to_bytes(1, "big", signed=False))
signature.write(0x30.to_bytes(1, "big", signed=False))
signature.write((sign_len - 2).to_bytes(1, "big", signed=False))
signature.write(0x02 .to_bytes(1, "big", signed=False))
signature.write(0x02.to_bytes(1, "big", signed=False))
signature.write(r_len.to_bytes(1, "big", signed=False))
signature.write(r)
signature.write(0x02 .to_bytes(1, "big", signed=False))
signature.write(0x02.to_bytes(1, "big", signed=False))
signature.write(s_len.to_bytes(1, "big", signed=False))
signature.write(s)
@@ -326,7 +321,10 @@ async def check_invoice_status(
payment = await get_wallet_payment(wallet_id, payment_hash, conn=conn)
if not payment:
return PaymentStatus(None)
status = await WALLET.get_invoice_status(payment.checking_id)
if payment.is_out:
status = await WALLET.get_payment_status(payment.checking_id)
else:
status = await WALLET.get_invoice_status(payment.checking_id)
if not payment.pending:
return status
if payment.is_out and status.failed:
@@ -340,5 +338,6 @@ async def check_invoice_status(
return status
# WARN: this same value must be used for balance check and passed to WALLET.pay_invoice(), it may cause a vulnerability if the values differ
def fee_reserve(amount_msat: int) -> int:
return max(1000, int(amount_msat * 0.01))
return max(2000, int(amount_msat * 0.01))