package nat import ( "sort" "strconv" "strings" ) type portSorter struct { ports []Port by func(i, j Port) bool } func (s *portSorter) Len() int { return len(s.ports) } func (s *portSorter) Swap(i, j int) { s.ports[i], s.ports[j] = s.ports[j], s.ports[i] } func (s *portSorter) Less(i, j int) bool { ip := s.ports[i] jp := s.ports[j] return s.by(ip, jp) } // Sort sorts a list of ports using the provided predicate // This function should compare `i` and `j`, returning true if `i` is // considered to be less than `j` func Sort(ports []Port, predicate func(i, j Port) bool) { s := &portSorter{ports, predicate} sort.Sort(s) } type portMapEntry struct { port Port binding PortBinding } type portMapSorter []portMapEntry func (s portMapSorter) Len() int { return len(s) } func (s portMapSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] } // sort the port so that the order is: // 1. port with larger specified bindings // 2. larger port // 3. port with tcp protocol func (s portMapSorter) Less(i, j int) bool { pi, pj := s[i].port, s[j].port hpi, hpj := toInt(s[i].binding.HostPort), toInt(s[j].binding.HostPort) return hpi > hpj || pi.Int() > pj.Int() || (pi.Int() == pj.Int() && strings.ToLower(pi.Proto()) == "tcp") } // SortPortMap sorts the list of ports and their respected mapping. The ports // will explicit HostPort will be placed first. func SortPortMap(ports []Port, bindings PortMap) { s := portMapSorter{} for _, p := range ports { if binding, ok := bindings[p]; ok { for _, b := range binding { s = append(s, portMapEntry{port: p, binding: b}) } bindings[p] = []PortBinding{} } else { s = append(s, portMapEntry{port: p}) } } sort.Sort(s) var ( i int pm = make(map[Port]struct{}) ) // reorder ports for _, entry := range s { if _, ok := pm[entry.port]; !ok { ports[i] = entry.port pm[entry.port] = struct{}{} i++ } // reorder bindings for this port if _, ok := bindings[entry.port]; ok { bindings[entry.port] = append(bindings[entry.port], entry.binding) } } } func toInt(s string) int64 { i, err := strconv.ParseInt(s, 10, 64) if err != nil { i = 0 } return i }