package netlink import ( "fmt" "net" "syscall" "github.com/vishvananda/netlink/nl" ) // RtAttr is shared so it is in netlink_linux.go // RouteAdd will add a route to the system. // Equivalent to: `ip route add $route` func RouteAdd(route *Route) error { req := nl.NewNetlinkRequest(syscall.RTM_NEWROUTE, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK) return routeHandle(route, req) } // RouteAdd will delete a route from the system. // Equivalent to: `ip route del $route` func RouteDel(route *Route) error { req := nl.NewNetlinkRequest(syscall.RTM_DELROUTE, syscall.NLM_F_ACK) return routeHandle(route, req) } func routeHandle(route *Route, req *nl.NetlinkRequest) error { if route.Dst.IP == nil && route.Src == nil && route.Gw == nil { return fmt.Errorf("one of Dst.IP, Src, or Gw must not be nil") } msg := nl.NewRtMsg() msg.Scope = uint8(route.Scope) family := -1 var rtAttrs []*nl.RtAttr if route.Dst.IP != nil { dstLen, _ := route.Dst.Mask.Size() msg.Dst_len = uint8(dstLen) dstFamily := nl.GetIPFamily(route.Dst.IP) family = dstFamily var dstData []byte if dstFamily == FAMILY_V4 { dstData = route.Dst.IP.To4() } else { dstData = route.Dst.IP.To16() } rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_DST, dstData)) } if route.Src != nil { srcFamily := nl.GetIPFamily(route.Src) if family != -1 && family != srcFamily { return fmt.Errorf("source and destination ip are not the same IP family") } family = srcFamily var srcData []byte if srcFamily == FAMILY_V4 { srcData = route.Src.To4() } else { srcData = route.Src.To16() } // The commonly used src ip for routes is actually PREFSRC rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_PREFSRC, srcData)) } if route.Gw != nil { gwFamily := nl.GetIPFamily(route.Gw) if family != -1 && family != gwFamily { return fmt.Errorf("gateway, source, and destination ip are not the same IP family") } family = gwFamily var gwData []byte if gwFamily == FAMILY_V4 { gwData = route.Gw.To4() } else { gwData = route.Gw.To16() } rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_GATEWAY, gwData)) } msg.Family = uint8(family) req.AddData(msg) for _, attr := range rtAttrs { req.AddData(attr) } var ( b = make([]byte, 4) native = nl.NativeEndian() ) base := route.Link.Attrs() native.PutUint32(b, uint32(base.Index)) req.AddData(nl.NewRtAttr(syscall.RTA_OIF, b)) _, err := req.Execute(syscall.NETLINK_ROUTE, 0) return err } // RouteList gets a list of routes in the system. // Equivalent to: `ip route show`. // The list can be filtered by link and ip family. func RouteList(link Link, family int) ([]Route, error) { req := nl.NewNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_DUMP) msg := nl.NewIfInfomsg(family) req.AddData(msg) msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE) if err != nil { return nil, err } index := 0 if link != nil { base := link.Attrs() ensureIndex(base) index = base.Index } native := nl.NativeEndian() res := make([]Route, 0) for _, m := range msgs { msg := nl.DeserializeRtMsg(m) if msg.Flags&syscall.RTM_F_CLONED != 0 { // Ignore cloned routes continue } if msg.Table != syscall.RT_TABLE_MAIN { // Ignore non-main tables continue } attrs, err := nl.ParseRouteAttr(m[msg.Len():]) if err != nil { return nil, err } route := Route{Scope: Scope(msg.Scope)} for _, attr := range attrs { switch attr.Attr.Type { case syscall.RTA_GATEWAY: route.Gw = net.IP(attr.Value) case syscall.RTA_PREFSRC: route.Src = net.IP(attr.Value) case syscall.RTA_DST: route.Dst = &net.IPNet{ IP: attr.Value, Mask: net.CIDRMask(int(msg.Dst_len), 8*len(attr.Value)), } case syscall.RTA_OIF: routeIndex := int(native.Uint32(attr.Value[0:4])) if link != nil && routeIndex != index { // Ignore routes from other interfaces continue } resLink, _ := LinkByIndex(routeIndex) route.Link = resLink } } res = append(res, route) } return res, nil }