def parse_fixed(byte_string):
if len(byte_string) != ONION_BYTE_LENGTH:
return None, "onion is the wrong length"
version, remainder, err = Namespace.pop_u8(byte_string)
if err:
return None, "could not pop version byte"
if version != 0:
return None, "unsupported onion packet version"
public_key, remainder, err = Namespace.pop_point(remainder)
if err:
return None, "could not pop public key: %s" % err
hop_payloads, remainder, err = Namespace.pop_bytes(HOP_PAYLOADS_LENGTH,
remainder)
if err:
return None, "could not pop hops_payloads: %s" % err
hmac, remainder, err = Namespace.pop_bytes(HMAC_LENGTH, remainder)
if err:
return None, "could not pop hmac: %s" % err
if len(remainder) != 0:
return None, "unexpected remaining bytes"
# TODO Check hmac for validity, need assocdata
return {'version': version,
'public_key': public_key,
'hop_payloads': hop_payloads,
'hmac': hmac}, None
def parse(byte_string):
scid, remainder, err = Namespace.pop_short_channel_id(byte_string)
if err:
return None, err
#print("scid: %s, remainder: %s\n" % (scid, remainder.hex()))
amt_to_forward, remainder, err = Namespace.pop_u64(remainder)
if err:
return None, err
#print("amt: %s, remainder: %s\n" % (amt_to_forward, remainder.hex()))
outgoing_cltv_value, remainder, err = Namespace.pop_u32(remainder)
if err:
return None, err
#print("outgoing: %s, remainder: %s\n" % (outgoing_cltv_value,
# remainder.hex()))
padding, remainder, err = Namespace.pop_bytes(12, remainder)
if err:
return None, err
#print("padding %s, remainder: %s\n" % (padding, remainder.hex()))
if len(remainder) != 0:
return None, "unexpected remaining bytes"
return {
'format': 'legacy',
'short_channel_id': scid,
'amt_to_forward': amt_to_forward,
'outgoing_cltv_value': outgoing_cltv_value,
'padding': padding
}, None
def parse_pixels(tlv):
pixels = []
if tlv.l % 5 != 0:
return None, "unexpected length"
remainder = tlv.v
while len(remainder) > 0:
pixel_hex, remainder, err = Namespace.pop_bytes(5, remainder)
if err:
return None, err
pixels.append(Pixel.from_bin(h2b(pixel_hex)))
return {'tlv_type_name': "bannerpunk_pixels", 'pixels': pixels}, None
def parse_payment_data(tlv):
payment_secret, remainder, err = Namespace.pop_bytes(32, tlv.v)
if err:
return None, err
total_msat, remainder, err = Namespace.pop_tu64(
len(remainder), remainder)
if err:
return None, err
if len(remainder) != 0:
return None, "unexpected remaining bytes"
return {
'tlv_type_name': 'payment_data',
'payment_secret': payment_secret,
'total_msat': total_msat
}, None