import hashlib import os import secrets import time from base64 import b64decode from datetime import datetime, timedelta import grpc import ring from decouple import config from django.utils import timezone from . import invoices_pb2 as invoicesrpc from . import invoices_pb2_grpc as invoicesstub from . import lightning_pb2 as lnrpc from . import lightning_pb2_grpc as lightningstub from . import router_pb2 as routerrpc from . import router_pb2_grpc as routerstub from . import verrpc_pb2 as verrpc from . import verrpc_pb2_grpc as verrpcstub ####### # Works with LND (c-lightning in the future for multi-vendor resiliance) ####### # Read tls.cert from file or .env variable string encoded as base64 try: CERT = open(os.path.join(config("LND_DIR"), "tls.cert"), "rb").read() except Exception: CERT = b64decode(config("LND_CERT_BASE64")) # Read macaroon from file or .env variable string encoded as base64 try: MACAROON = open( os.path.join(config("LND_DIR"), config("MACAROON_path")), "rb" ).read() except Exception: MACAROON = b64decode(config("LND_MACAROON_BASE64")) LND_GRPC_HOST = config("LND_GRPC_HOST") DISABLE_ONCHAIN = config("DISABLE_ONCHAIN", cast=bool, default=True) MAX_SWAP_AMOUNT = config("MAX_SWAP_AMOUNT", cast=int, default=500000) class LNNode: os.environ["GRPC_SSL_CIPHER_SUITES"] = "HIGH+ECDSA" def metadata_callback(context, callback): callback([("macaroon", MACAROON.hex())], None) ssl_creds = grpc.ssl_channel_credentials(CERT) auth_creds = grpc.metadata_call_credentials(metadata_callback) combined_creds = grpc.composite_channel_credentials(ssl_creds, auth_creds) channel = grpc.secure_channel(LND_GRPC_HOST, combined_creds) lightningstub = lightningstub.LightningStub(channel) invoicesstub = invoicesstub.InvoicesStub(channel) routerstub = routerstub.RouterStub(channel) verrpcstub = verrpcstub.VersionerStub(channel) lnrpc = lnrpc invoicesrpc = invoicesrpc routerrpc = routerrpc verrpc = verrpc payment_failure_context = { 0: "Payment isn't failed (yet)", 1: "There are more routes to try, but the payment timeout was exceeded.", 2: "All possible routes were tried and failed permanently. Or were no routes to the destination at all.", 3: "A non-recoverable error has occured.", 4: "Payment details incorrect (unknown hash, invalid amt or invalid final cltv delta)", 5: "Insufficient local balance.", } @classmethod def get_version(cls): try: request = verrpc.VersionRequest() response = cls.verrpcstub.GetVersion(request) return "v" + response.version except Exception as e: print(e) return None @classmethod def decode_payreq(cls, invoice): """Decodes a lightning payment request (invoice)""" request = lnrpc.PayReqString(pay_req=invoice) response = cls.lightningstub.DecodePayReq(request) return response @classmethod def estimate_fee(cls, amount_sats, target_conf=2, min_confs=1): """Returns estimated fee for onchain payouts""" # We assume segwit. Use hardcoded address as shortcut so there is no need of user inputs yet. request = lnrpc.EstimateFeeRequest( AddrToAmount={"bc1qgxwaqe4m9mypd7ltww53yv3lyxhcfnhzzvy5j3": amount_sats}, target_conf=target_conf, min_confs=min_confs, spend_unconfirmed=False, ) response = cls.lightningstub.EstimateFee(request) return { "mining_fee_sats": response.fee_sat, "mining_fee_rate": response.sat_per_vbyte, } wallet_balance_cache = {} @ring.dict(wallet_balance_cache, expire=10) # keeps in cache for 10 seconds @classmethod def wallet_balance(cls): """Returns onchain balance""" request = lnrpc.WalletBalanceRequest() response = cls.lightningstub.WalletBalance(request) return { "total_balance": response.total_balance, "confirmed_balance": response.confirmed_balance, "unconfirmed_balance": response.unconfirmed_balance, } channel_balance_cache = {} @ring.dict(channel_balance_cache, expire=10) # keeps in cache for 10 seconds @classmethod def channel_balance(cls): """Returns channels balance""" request = lnrpc.ChannelBalanceRequest() response = cls.lightningstub.ChannelBalance(request) return { "local_balance": response.local_balance.sat, "remote_balance": response.remote_balance.sat, "unsettled_local_balance": response.unsettled_local_balance.sat, "unsettled_remote_balance": response.unsettled_remote_balance.sat, } @classmethod def pay_onchain(cls, onchainpayment, queue_code=5, on_mempool_code=2): """Send onchain transaction for buyer payouts""" if DISABLE_ONCHAIN or onchainpayment.sent_satoshis > MAX_SWAP_AMOUNT: return False request = lnrpc.SendCoinsRequest( addr=onchainpayment.address, amount=int(onchainpayment.sent_satoshis), sat_per_vbyte=int(onchainpayment.mining_fee_rate), label=str("Payout order #" + str(onchainpayment.order_paid_TX.id)), spend_unconfirmed=config("SPEND_UNCONFIRMED", default=False, cast=bool), ) # Cheap security measure to ensure there has been some non-deterministic time between request and DB check delay = ( secrets.randbelow(2**256) / (2**256) * 10 ) # Random uniform 0 to 5 secs with good entropy time.sleep(3 + delay) if onchainpayment.status == queue_code: # Changing the state to "MEMPO" should be atomic with SendCoins. onchainpayment.status = on_mempool_code onchainpayment.save() response = cls.lightningstub.SendCoins(request) if response.txid: onchainpayment.txid = response.txid onchainpayment.broadcasted = True onchainpayment.save() return True elif onchainpayment.status == on_mempool_code: # Bug, double payment attempted return True @classmethod def cancel_return_hold_invoice(cls, payment_hash): """Cancels or returns a hold invoice""" request = invoicesrpc.CancelInvoiceMsg(payment_hash=bytes.fromhex(payment_hash)) response = cls.invoicesstub.CancelInvoice(request) # Fix this: tricky because canceling sucessfully an invoice has no response. TODO return str(response) == "" # True if no response, false otherwise. @classmethod def settle_hold_invoice(cls, preimage): """settles a hold invoice""" request = invoicesrpc.SettleInvoiceMsg(preimage=bytes.fromhex(preimage)) response = cls.invoicesstub.SettleInvoice(request) # Fix this: tricky because settling sucessfully an invoice has None response. TODO return str(response) == "" # True if no response, false otherwise. @classmethod def gen_hold_invoice( cls, num_satoshis, description, invoice_expiry, cltv_expiry_blocks ): """Generates hold invoice""" hold_payment = {} # The preimage is a random hash of 256 bits entropy preimage = hashlib.sha256(secrets.token_bytes(nbytes=32)).digest() # Its hash is used to generate the hold invoice r_hash = hashlib.sha256(preimage).digest() request = invoicesrpc.AddHoldInvoiceRequest( memo=description, value=num_satoshis, hash=r_hash, expiry=int( invoice_expiry * 1.5 ), # actual expiry is padded by 50%, if tight, wrong client system clock will say invoice is expired. cltv_expiry=cltv_expiry_blocks, ) response = cls.invoicesstub.AddHoldInvoice(request) hold_payment["invoice"] = response.payment_request payreq_decoded = cls.decode_payreq(hold_payment["invoice"]) hold_payment["preimage"] = preimage.hex() hold_payment["payment_hash"] = payreq_decoded.payment_hash hold_payment["created_at"] = timezone.make_aware( datetime.fromtimestamp(payreq_decoded.timestamp) ) hold_payment["expires_at"] = hold_payment["created_at"] + timedelta( seconds=payreq_decoded.expiry ) hold_payment["cltv_expiry"] = cltv_expiry_blocks return hold_payment @classmethod def validate_hold_invoice_locked(cls, lnpayment): """Checks if hold invoice is locked""" from api.models import LNPayment request = invoicesrpc.LookupInvoiceMsg( payment_hash=bytes.fromhex(lnpayment.payment_hash) ) response = cls.invoicesstub.LookupInvoiceV2(request) # Will fail if 'unable to locate invoice'. Happens if invoice expiry # time has passed (but these are 15% padded at the moment). Should catch it # and report back that the invoice has expired (better robustness) if response.state == 0: # OPEN pass if response.state == 1: # SETTLED pass if response.state == 2: # CANCELLED pass if response.state == 3: # ACCEPTED (LOCKED) lnpayment.expiry_height = response.htlcs[0].expiry_height lnpayment.status = LNPayment.Status.LOCKED lnpayment.save() return True @classmethod def lookup_invoice_status(cls, lnpayment): """ Returns the status (as LNpayment.Status) of the given payment_hash If unchanged, returns the previous status """ from api.models import LNPayment status = lnpayment.status lnd_response_state_to_lnpayment_status = { 0: LNPayment.Status.INVGEN, # OPEN 1: LNPayment.Status.SETLED, # SETTLED 2: LNPayment.Status.CANCEL, # CANCELLED 3: LNPayment.Status.LOCKED, # ACCEPTED } try: # this is similar to LNNnode.validate_hold_invoice_locked request = invoicesrpc.LookupInvoiceMsg( payment_hash=bytes.fromhex(lnpayment.payment_hash) ) response = cls.invoicesstub.LookupInvoiceV2(request) # try saving expiry height if hasattr(response, "htlcs"): try: lnpayment.expiry_height = response.htlcs[0].expiry_height except Exception: pass status = lnd_response_state_to_lnpayment_status[response.state] lnpayment.status = status lnpayment.save() except Exception as e: # If it fails at finding the invoice: it has been canceled. # In RoboSats DB we make a distinction between cancelled and returned (LND does not) if "unable to locate invoice" in str(e): print(str(e)) status = LNPayment.Status.CANCEL lnpayment.status = status lnpayment.save() # LND restarted. if "wallet locked, unlock it" in str(e): print(str(timezone.now()) + " :: Wallet Locked") # Other write to logs else: print(str(e)) return status @classmethod def resetmc(cls): request = routerrpc.ResetMissionControlRequest() _ = cls.routerstub.ResetMissionControl(request) return True @classmethod def validate_ln_invoice(cls, invoice, num_satoshis, routing_budget_ppm): """Checks if the submited LN invoice comforms to expectations""" payout = { "valid": False, "context": None, "description": None, "payment_hash": None, "created_at": None, "expires_at": None, } try: payreq_decoded = cls.decode_payreq(invoice) except Exception: payout["context"] = { "bad_invoice": "Does not look like a valid lightning invoice" } return payout # Some wallet providers (e.g. Muun) force routing through a private channel with high fees >1500ppm # These payments will fail. So it is best to let the user know in advance this invoice is not valid. route_hints = payreq_decoded.route_hints # Max amount RoboSats will pay for routing if routing_budget_ppm == 0: max_routing_fee_sats = max( num_satoshis * float(config("PROPORTIONAL_ROUTING_FEE_LIMIT")), float(config("MIN_FLAT_ROUTING_FEE_LIMIT_REWARD")), ) else: max_routing_fee_sats = int( float(num_satoshis) * float(routing_budget_ppm) / 1000000 ) if route_hints: routes_cost = [] # For every hinted route... for hinted_route in route_hints: route_cost = 0 # ...add up the cost of every hinted hop... for hop_hint in hinted_route.hop_hints: route_cost += hop_hint.fee_base_msat / 1000 route_cost += ( hop_hint.fee_proportional_millionths * num_satoshis / 1000000 ) # ...and store the cost of the route to the array routes_cost.append(route_cost) # If the cheapest possible private route is more expensive than what RoboSats is willing to pay if min(routes_cost) >= max_routing_fee_sats: payout["context"] = { "bad_invoice": "The invoice hinted private routes are not payable within the submitted routing budget." } return payout if payreq_decoded.num_satoshis == 0: payout["context"] = { "bad_invoice": "The invoice provided has no explicit amount" } return payout if not payreq_decoded.num_satoshis == num_satoshis: payout["context"] = { "bad_invoice": "The invoice provided is not for " + "{:,}".format(num_satoshis) + " Sats" } return payout payout["created_at"] = timezone.make_aware( datetime.fromtimestamp(payreq_decoded.timestamp) ) payout["expires_at"] = payout["created_at"] + timedelta( seconds=payreq_decoded.expiry ) if payout["expires_at"] < timezone.now(): payout["context"] = { "bad_invoice": "The invoice provided has already expired" } return payout payout["valid"] = True payout["description"] = payreq_decoded.description payout["payment_hash"] = payreq_decoded.payment_hash return payout @classmethod def pay_invoice(cls, lnpayment): """Sends sats. Used for rewards payouts""" from api.models import LNPayment fee_limit_sat = int( max( lnpayment.num_satoshis * float(config("PROPORTIONAL_ROUTING_FEE_LIMIT")), float(config("MIN_FLAT_ROUTING_FEE_LIMIT_REWARD")), ) ) # 200 ppm or 10 sats timeout_seconds = int(config("REWARDS_TIMEOUT_SECONDS")) request = routerrpc.SendPaymentRequest( payment_request=lnpayment.invoice, fee_limit_sat=fee_limit_sat, timeout_seconds=timeout_seconds, ) for response in cls.routerstub.SendPaymentV2(request): if response.status == 0: # Status 0 'UNKNOWN' # Not sure when this status happens pass if response.status == 1: # Status 1 'IN_FLIGHT' pass if response.status == 3: # Status 3 'FAILED' """0 Payment isn't failed (yet). 1 There are more routes to try, but the payment timeout was exceeded. 2 All possible routes were tried and failed permanently. Or were no routes to the destination at all. 3 A non-recoverable error has occured. 4 Payment details incorrect (unknown hash, invalid amt or invalid final cltv delta) 5 Insufficient local balance. """ failure_reason = cls.payment_failure_context[response.failure_reason] lnpayment.failure_reason = response.failure_reason lnpayment.status = LNPayment.Status.FAILRO lnpayment.save() return False, failure_reason if response.status == 2: # STATUS 'SUCCEEDED' lnpayment.status = LNPayment.Status.SUCCED lnpayment.fee = float(response.fee_msat) / 1000 lnpayment.preimage = response.payment_preimage lnpayment.save() return True, None return False @classmethod def follow_send_payment(cls, lnpayment, fee_limit_sat, timeout_seconds): """ Sends sats to buyer, continuous update. Has a lot of boilerplate to correctly handle every possible condition and failure case. """ from api.models import LNPayment, Order hash = lnpayment.payment_hash request = cls.routerrpc.SendPaymentRequest( payment_request=lnpayment.invoice, fee_limit_sat=fee_limit_sat, timeout_seconds=timeout_seconds, allow_self_payment=True, ) order = lnpayment.order_paid_LN if order.trade_escrow.num_satoshis < lnpayment.num_satoshis: print(f"Order: {order.id} Payout is larger than collateral !?") return def handle_response(response, was_in_transit=False): lnpayment.status = LNPayment.Status.FLIGHT lnpayment.in_flight = True lnpayment.save() order.status = Order.Status.PAY order.save() if response.status == 0: # Status 0 'UNKNOWN' # Not sure when this status happens print(f"Order: {order.id} UNKNOWN. Hash {hash}") lnpayment.in_flight = False lnpayment.save() if response.status == 1: # Status 1 'IN_FLIGHT' print(f"Order: {order.id} IN_FLIGHT. Hash {hash}") # If payment was already "payment is in transition" we do not # want to spawn a new thread every 3 minutes to check on it. # in case this thread dies, let's move the last_routing_time # 20 minutes in the future so another thread spawns. if was_in_transit: lnpayment.last_routing_time = timezone.now() + timedelta(minutes=20) lnpayment.save() if response.status == 3: # Status 3 'FAILED' lnpayment.status = LNPayment.Status.FAILRO lnpayment.last_routing_time = timezone.now() lnpayment.routing_attempts += 1 lnpayment.failure_reason = response.failure_reason lnpayment.in_flight = False if lnpayment.routing_attempts > 2: lnpayment.status = LNPayment.Status.EXPIRE lnpayment.routing_attempts = 0 lnpayment.save() order.status = Order.Status.FAI order.expires_at = timezone.now() + timedelta( seconds=order.t_to_expire(Order.Status.FAI) ) order.save() print( f"Order: {order.id} FAILED. Hash: {hash} Reason: {cls.payment_failure_context[response.failure_reason]}" ) return { "succeded": False, "context": f"payment failure reason: {cls.payment_failure_context[response.failure_reason]}", } if response.status == 2: # Status 2 'SUCCEEDED' print(f"Order: {order.id} SUCCEEDED. Hash: {hash}") lnpayment.status = LNPayment.Status.SUCCED lnpayment.fee = float(response.fee_msat) / 1000 lnpayment.preimage = response.payment_preimage lnpayment.save() order.status = Order.Status.SUC order.expires_at = timezone.now() + timedelta( seconds=order.t_to_expire(Order.Status.SUC) ) order.save() results = {"succeded": True} return results try: for response in cls.routerstub.SendPaymentV2(request): handle_response(response) except Exception as e: if "invoice expired" in str(e): print(f"Order: {order.id}. INVOICE EXPIRED. Hash: {hash}") lnpayment.status = LNPayment.Status.EXPIRE lnpayment.last_routing_time = timezone.now() lnpayment.in_flight = False lnpayment.save() order.status = Order.Status.FAI order.expires_at = timezone.now() + timedelta( seconds=order.t_to_expire(Order.Status.FAI) ) order.save() results = { "succeded": False, "context": "The payout invoice has expired", } return results elif "payment is in transition" in str(e): print(f"Order: {order.id} ALREADY IN TRANSITION. Hash: {hash}.") request = routerrpc.TrackPaymentRequest( payment_hash=bytes.fromhex(hash) ) for response in cls.routerstub.TrackPaymentV2(request): handle_response(response, was_in_transit=True) elif "invoice is already paid" in str(e): print(f"Order: {order.id} ALREADY PAID. Hash: {hash}.") request = routerrpc.TrackPaymentRequest( payment_hash=bytes.fromhex(hash) ) for response in cls.routerstub.TrackPaymentV2(request): handle_response(response) else: print(str(e)) @classmethod def double_check_htlc_is_settled(cls, payment_hash): """Just as it sounds. Better safe than sorry!""" request = invoicesrpc.LookupInvoiceMsg(payment_hash=bytes.fromhex(payment_hash)) response = cls.invoicesstub.LookupInvoiceV2(request) return ( response.state == 1 ) # LND states: 0 OPEN, 1 SETTLED, 3 ACCEPTED, GRPC_ERROR status 5 when cancelled/returned