if forwarding_ip != WAN_ip:
dst_ip = forwarding_ip
else:
dst_ip = network.dst_ip
if dst_ip != forwarding_ip:
print('forwaring to', forwarding_table[network.dst_ip])
dst_mac = util.ip2mac(dst_ip)
linklayer.sendto(dst_mac, frame)
elif (network.dst_ip, transport.dst_port) in NAT_in :
network.dst_ip, transport.dst_port = NAT_in[(network.dst_ip, transport.dst_port)]
frame = pack(network, transport)
IP.push(frame)
else:
ICMP.host_unreachable(WAN_ip, network.src_ip)
linklayer = LinkLayer(callback)
# def is_reachable_host(dst_ip):
# '''
# Private method for check if the current dst_ip is legal
# :param dst_ip: dst_ip
# :return: boolean
# '''
# ip_list = [util.get_local_ipv4_address()]
# for ele in NAT_in.keys():
# ip_list.append(ele[0])
# if dst_ip not in forwarding_table.values() or ip_list:
# return False
# return True
