def ip_checksum(buf):
sum = 0
if len(buf) & 0x01:
- buf += '\0x00'
+ buf += '\x00'
for i in range(0, len(buf), 2):
val, = struct.unpack('H', buf[i:i+2])
sum += val
def build_dhcp_ack(dst_ll, src_ll, ip_src, ip_dst, yiaddr, chaddr,
subnet_mask="255.255.255.0", truncated_opt=False,
- wrong_magic=False, force_tot_len=None, no_dhcp=False):
+ wrong_magic=False, force_tot_len=None, no_dhcp=False,
+ udp_checksum=True):
_dst_ll = binascii.unhexlify(dst_ll.replace(':',''))
_src_ll = binascii.unhexlify(src_ll.replace(':',''))
proto = '\x08\x00'
payload = struct.pack('>BBBBL3BB', 2, 1, 6, 0, 12345, 0, 0, 0, 0)
payload += _ciaddr + _yiaddr + _siaddr + _giaddr + _chaddr + 192*'\x00'
- udp = struct.pack('>HHHH', 67, 68, 8 + len(payload), 0) + payload
+ if udp_checksum:
+ pseudohdr = _ip_src + _ip_dst + struct.pack('>BBH', 0, 17,
+ 8 + len(payload))
+ udphdr = struct.pack('>HHHH', 67, 68, 8 + len(payload), 0)
+ checksum, = struct.unpack('>H', ip_checksum(pseudohdr + udphdr + payload))
+ else:
+ checksum = 0
+ udp = struct.pack('>HHHH', 67, 68, 8 + len(payload), checksum) + payload
if force_tot_len:
tot_len = force_tot_len
# Change address and verify unicast
pkt = build_dhcp_ack(dst_ll=addr0, src_ll=bssid,
ip_src="192.168.1.1", ip_dst="255.255.255.255",
- yiaddr="192.168.1.123", chaddr=addr0)
+ yiaddr="192.168.1.123", chaddr=addr0,
+ udp_checksum=False)
if "OK" not in hapd.request("DATA_TEST_FRAME ifname=ap-br0 " + binascii.hexlify(pkt)):
raise Exception("DATA_TEST_FRAME failed")