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| type rtInfo struct { Dst net.IPNet Gateway, PrefSrc net.IP OutputIface uint32 Priority uint32 } type GateWay struct { InterfaceName string `json:"interface_name"` GateWay string `json:"gate_way"` Ip string `json:"ip"` } type routeSlice []*rtInfo
type router struct { ifaces []net.Interface addrs []net.IP v4 routeSlice }
func getRouteInfo() (*router, error) { rtr := &router{}
tab, err := syscall.NetlinkRIB(syscall.RTM_GETROUTE, syscall.AF_INET) if err != nil { return nil, err }
msgs, err := syscall.ParseNetlinkMessage(tab) if err != nil { return nil, err }
for _, m := range msgs { switch m.Header.Type { case syscall.NLMSG_DONE: break case syscall.RTM_NEWROUTE: rtmsg := (*syscall.RtMsg)(unsafe.Pointer(&m.Data[0])) attrs, err := syscall.ParseNetlinkRouteAttr(&m) if err != nil { return nil, err } routeInfo := rtInfo{} rtr.v4 = append(rtr.v4, &routeInfo) for _, attr:= range attrs { switch attr.Attr.Type { case syscall.RTA_DST: routeInfo.Dst.IP = net.IP(attr.Value) routeInfo.Dst.Mask = net.CIDRMask(int(rtmsg.Dst_len), len(attr.Value)*8) case syscall.RTA_GATEWAY: routeInfo.Gateway = net.IPv4(attr.Value[0], attr.Value[1], attr.Value[2], attr.Value[3]) case syscall.RTA_OIF: routeInfo.OutputIface = *(*uint32)(unsafe.Pointer(&attr.Value[0])) case syscall.RTA_PRIORITY: routeInfo.Priority = *(*uint32)(unsafe.Pointer(&attr.Value[0])) case syscall.RTA_PREFSRC: routeInfo.PrefSrc = net.IPv4(attr.Value[0], attr.Value[1], attr.Value[2], attr.Value[3]) } } } }
sort.Slice(rtr.v4, func(i, j int) bool { return rtr.v4[i].Priority < rtr.v4[j].Priority })
ifaces, err := net.Interfaces() if err != nil { return nil, err }
for i, iface := range ifaces {
if i != iface.Index - 1 { break }
if iface.Flags & net.FlagUp == 0{ continue } rtr.ifaces = append(rtr.ifaces, iface) ifaceAddrs, err := iface.Addrs() if err != nil { return nil, err } var addrs net.IP for _, addr := range ifaceAddrs { if inet, ok := addr.(*net.IPNet); ok { if v4 := inet.IP.To4(); v4 != nil { if addrs == nil { addrs = v4 } } } } rtr.addrs = append(rtr.addrs, addrs) } return rtr, nil }
func getGateWay() []GateWay { newRoute, err := getRouteInfo() if err != nil { fmt.Println(err) return nil } var gateWays []GateWay for _, rt := range newRoute.v4 { var gateway GateWay if rt.Gateway != nil { gateway.InterfaceName = newRoute.ifaces[rt.OutputIface-1].Name gateway.GateWay = rt.Gateway.String() gateway.Ip = newRoute.addrs[rt.OutputIface-1].String() gateWays = append(gateWays, gateway) } } return gateWays }
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