def alloc_port(src_ip, src_port, dst_ip, dst_port, switch, switch_port):
"""
Allocate a temporary EIP:port for this flow
"""
handler = DBHandler()
if src_port == 0:
return
nat_rule = handler.get(int_ip=src_ip)
if nat_rule:
eip = nat_rule[0].get('ext_ip')
for port in range(1, 65536):
if port not in used_ports.get(eip).keys():
#get unused flow ID
for flowid in range(0, 999):
if flowid not in used_flowid:
used_flowid.append(flowid)
break
else:
return 'ERROR'
used_ports.get(eip)[port] = (src_ip, src_port, dst_ip, dst_port, flowid)
#set SNAT flow
egress_flow = [src_ip, src_port, dst_ip, dst_port]
of_handler.set_snat(egress_flow, eip, port, 1000 + flowid, switch)
#set DNAT flow
ingress_flow = [dst_ip, dst_port, eip, port]
of_handler.set_dnat(ingress_flow, src_ip, src_port, 2000 + flowid, switch, switch_port)
#set ROUTE flow
of_handler.set_route(ingress_flow, int(switch) + 1, 3000 + flowid, GWID)
return json.dumps([eip, port])
return 'ERROR'
def expire_port(src_ip, src_port, dst_ip, dst_port, switch, switch_port):
"""
Expire a temporary EIP:port for this flow
"""
handler = DBHandler()
nat_rule = handler.get(int_ip=src_ip)
if nat_rule:
eip = nat_rule[0].get('ext_ip')
for port in used_ports.get(eip):
if used_ports.get(eip).get(port)[:4] == (src_ip, src_port, dst_ip, dst_port):
flow = used_ports.get(eip).pop(port)
flowid = flow.pop(4)
#set flowid unused
used_flowid.remove(flowid)
#rm ROUTE flow
ingress_flow = [dst_ip, dst_port, eip, src_port]
of_handler.set_route(ingress_flow, switch + 1, flowid, GWID, method='DELETE')
return 'OK'
