def _api_handle_path_request(self, msg, meta):
"""
Path request:
| \x00 (1B) | ISD (12bits) | AS (20bits) |
Reply:
|p1_len(1B)|p1((p1_len*8)B)|fh_type(1B)|fh_IP(?B)|fh_port(2B)|mtu(2B)|
p1_if_count(1B)|p1_if_1(5B)|...|p1_if_n(5B)|
p2_len(1B)|...
or b"" when no path found.
"""
dst_ia = ISD_AS(msg[1:ISD_AS.LEN + 1])
thread = threading.current_thread()
thread.name = "SCIONDaemon API id:%s %s -> %s" % (
thread.ident, self.addr.isd_as, dst_ia)
paths = self.get_paths(dst_ia)
reply = []
logging.debug("Replying to api request for %s with %d paths", dst_ia,
len(paths))
for path in paths:
raw_path = path.pack()
fwd_if = path.get_fwd_if()
# Set dummy host addr if path is empty.
if fwd_if == 0:
haddr, port = HostAddrNone(), SCION_UDP_EH_DATA_PORT
else:
br = self.ifid2br[fwd_if]
haddr, port = br.addr, br.port
path_len = len(raw_path) // 8
reply.append(
struct.pack("!B", path_len) + raw_path +
struct.pack("!B", haddr.TYPE) + haddr.pack() +
struct.pack("!H", port) + struct.pack("!H", path.mtu) +
struct.pack("!B", len(path.interfaces)))
for interface in path.interfaces:
isd_as, link = interface
reply.append(isd_as.pack())
reply.append(struct.pack("!H", link))
self.send_meta(b"".join(reply), meta)
def _build_packet(self, dst_host=None, path=None, ext_hdrs=(),
dst_ia=None, payload=None, dst_port=0):
if dst_host is None:
dst_host = HostAddrNone()
if dst_ia is None:
dst_ia = self.addr.isd_as
if path is None:
path = SCIONPath()
if payload is None:
payload = PayloadRaw()
dst_addr = SCIONAddr.from_values(dst_ia, dst_host)
cmn_hdr, addr_hdr = build_base_hdrs(dst_addr, self.addr)
udp_hdr = SCIONUDPHeader.from_values(
self.addr, self._port, dst_addr, dst_port)
return SCIONL4Packet.from_values(
cmn_hdr, addr_hdr, path, ext_hdrs, udp_hdr, payload)