func routeHandle(route *Route, req *nl.NetlinkRequest) error { if (route.Dst == nil || 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 != nil && 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() ) native.PutUint32(b, uint32(route.LinkIndex)) req.AddData(nl.NewRtAttr(syscall.RTA_OIF, b)) _, err := req.Execute(syscall.NETLINK_ROUTE, 0) return err }
// 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, nl.NewRtMsg()) }