package router import ( "fmt" "hash/fnv" "strings" "github.com/olekukonko/tablewriter" ) var ( // DefaultLocalMetric is default route cost for local network DefaultLocalMetric = 1 // DefaultNetworkMetric is default route cost for micro network DefaultNetworkMetric = 10 ) // RoutePolicy defines routing table addition policy type RoutePolicy int const ( // AddIfNotExist adds the route if it does not exist AddIfNotExists RoutePolicy = iota // OverrideIfExists overrides route if it already exists OverrideIfExists // IgnoreIfExists instructs to not modify existing route IgnoreIfExists ) // String returns human reprensentation of policy func (p RoutePolicy) String() string { switch p { case AddIfNotExists: return "ADD_IF_NOT_EXISTS" case OverrideIfExists: return "OVERRIDE_IF_EXISTS" case IgnoreIfExists: return "IGNORE_IF_EXISTS" default: return "UNKNOWN" } } // Route is network route type Route struct { // Destination is destination address Destination string // Gateway is route gateway Gateway string // Router is the network router address Router string // Network is micro network address Network string // Metric is the route cost metric Metric int // Policy defines route policy Policy RoutePolicy } // Hash returns route hash sum. func (r *Route) Hash() uint64 { h := fnv.New64() h.Reset() h.Write([]byte(r.Destination + r.Gateway + r.Network)) return h.Sum64() } // String allows to print the route func (r Route) String() string { // this will help us build routing table string sb := &strings.Builder{} // create nice table printing structure table := tablewriter.NewWriter(sb) table.SetHeader([]string{"Destination", "Gateway", "Router", "Network", "Metric"}) strRoute := []string{ r.Destination, r.Gateway, r.Router, r.Network, fmt.Sprintf("%d", r.Metric), } table.Append(strRoute) // render table into sb table.Render() return sb.String() }