674 lines
18 KiB
Go
674 lines
18 KiB
Go
package netlink
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import (
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"fmt"
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"net"
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"strings"
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"syscall"
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"github.com/vishvananda/netlink/nl"
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"github.com/vishvananda/netns"
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)
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// RtAttr is shared so it is in netlink_linux.go
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const (
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SCOPE_UNIVERSE Scope = syscall.RT_SCOPE_UNIVERSE
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SCOPE_SITE Scope = syscall.RT_SCOPE_SITE
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SCOPE_LINK Scope = syscall.RT_SCOPE_LINK
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SCOPE_HOST Scope = syscall.RT_SCOPE_HOST
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SCOPE_NOWHERE Scope = syscall.RT_SCOPE_NOWHERE
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)
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const (
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RT_FILTER_PROTOCOL uint64 = 1 << (1 + iota)
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RT_FILTER_SCOPE
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RT_FILTER_TYPE
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RT_FILTER_TOS
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RT_FILTER_IIF
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RT_FILTER_OIF
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RT_FILTER_DST
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RT_FILTER_SRC
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RT_FILTER_GW
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RT_FILTER_TABLE
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)
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const (
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FLAG_ONLINK NextHopFlag = syscall.RTNH_F_ONLINK
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FLAG_PERVASIVE NextHopFlag = syscall.RTNH_F_PERVASIVE
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)
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var testFlags = []flagString{
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{f: FLAG_ONLINK, s: "onlink"},
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{f: FLAG_PERVASIVE, s: "pervasive"},
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}
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func listFlags(flag int) []string {
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var flags []string
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for _, tf := range testFlags {
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if flag&int(tf.f) != 0 {
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flags = append(flags, tf.s)
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}
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}
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return flags
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}
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func (r *Route) ListFlags() []string {
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return listFlags(r.Flags)
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}
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func (n *NexthopInfo) ListFlags() []string {
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return listFlags(n.Flags)
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}
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type MPLSDestination struct {
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Labels []int
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}
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func (d *MPLSDestination) Family() int {
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return nl.FAMILY_MPLS
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}
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func (d *MPLSDestination) Decode(buf []byte) error {
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d.Labels = nl.DecodeMPLSStack(buf)
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return nil
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}
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func (d *MPLSDestination) Encode() ([]byte, error) {
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return nl.EncodeMPLSStack(d.Labels...), nil
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}
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func (d *MPLSDestination) String() string {
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s := make([]string, 0, len(d.Labels))
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for _, l := range d.Labels {
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s = append(s, fmt.Sprintf("%d", l))
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}
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return strings.Join(s, "/")
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}
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type MPLSEncap struct {
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Labels []int
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}
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func (e *MPLSEncap) Type() int {
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return nl.LWTUNNEL_ENCAP_MPLS
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}
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func (e *MPLSEncap) Decode(buf []byte) error {
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if len(buf) < 4 {
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return fmt.Errorf("Lack of bytes")
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}
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native := nl.NativeEndian()
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l := native.Uint16(buf)
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if len(buf) < int(l) {
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return fmt.Errorf("Lack of bytes")
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}
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buf = buf[:l]
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typ := native.Uint16(buf[2:])
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if typ != nl.MPLS_IPTUNNEL_DST {
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return fmt.Errorf("Unknown MPLS Encap Type: %d", typ)
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}
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e.Labels = nl.DecodeMPLSStack(buf[4:])
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return nil
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}
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func (e *MPLSEncap) Encode() ([]byte, error) {
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s := nl.EncodeMPLSStack(e.Labels...)
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native := nl.NativeEndian()
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hdr := make([]byte, 4)
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native.PutUint16(hdr, uint16(len(s)+4))
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native.PutUint16(hdr[2:], nl.MPLS_IPTUNNEL_DST)
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return append(hdr, s...), nil
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}
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func (e *MPLSEncap) String() string {
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s := make([]string, 0, len(e.Labels))
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for _, l := range e.Labels {
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s = append(s, fmt.Sprintf("%d", l))
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}
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return strings.Join(s, "/")
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}
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// RouteAdd will add a route to the system.
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// Equivalent to: `ip route add $route`
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func RouteAdd(route *Route) error {
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return pkgHandle.RouteAdd(route)
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}
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// RouteAdd will add a route to the system.
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// Equivalent to: `ip route add $route`
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func (h *Handle) RouteAdd(route *Route) error {
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flags := syscall.NLM_F_CREATE | syscall.NLM_F_EXCL | syscall.NLM_F_ACK
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req := h.newNetlinkRequest(syscall.RTM_NEWROUTE, flags)
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return h.routeHandle(route, req, nl.NewRtMsg())
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}
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// RouteReplace will add a route to the system.
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// Equivalent to: `ip route replace $route`
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func RouteReplace(route *Route) error {
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return pkgHandle.RouteReplace(route)
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}
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// RouteReplace will add a route to the system.
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// Equivalent to: `ip route replace $route`
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func (h *Handle) RouteReplace(route *Route) error {
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flags := syscall.NLM_F_CREATE | syscall.NLM_F_REPLACE | syscall.NLM_F_ACK
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req := h.newNetlinkRequest(syscall.RTM_NEWROUTE, flags)
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return h.routeHandle(route, req, nl.NewRtMsg())
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}
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// RouteDel will delete a route from the system.
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// Equivalent to: `ip route del $route`
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func RouteDel(route *Route) error {
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return pkgHandle.RouteDel(route)
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}
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// RouteDel will delete a route from the system.
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// Equivalent to: `ip route del $route`
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func (h *Handle) RouteDel(route *Route) error {
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req := h.newNetlinkRequest(syscall.RTM_DELROUTE, syscall.NLM_F_ACK)
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return h.routeHandle(route, req, nl.NewRtDelMsg())
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}
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func (h *Handle) routeHandle(route *Route, req *nl.NetlinkRequest, msg *nl.RtMsg) error {
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if (route.Dst == nil || route.Dst.IP == nil) && route.Src == nil && route.Gw == nil && route.MPLSDst == nil {
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return fmt.Errorf("one of Dst.IP, Src, or Gw must not be nil")
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}
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family := -1
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var rtAttrs []*nl.RtAttr
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if route.Dst != nil && route.Dst.IP != nil {
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dstLen, _ := route.Dst.Mask.Size()
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msg.Dst_len = uint8(dstLen)
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dstFamily := nl.GetIPFamily(route.Dst.IP)
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family = dstFamily
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var dstData []byte
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if dstFamily == FAMILY_V4 {
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dstData = route.Dst.IP.To4()
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} else {
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dstData = route.Dst.IP.To16()
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}
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rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_DST, dstData))
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} else if route.MPLSDst != nil {
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family = nl.FAMILY_MPLS
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msg.Dst_len = uint8(20)
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msg.Type = syscall.RTN_UNICAST
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rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_DST, nl.EncodeMPLSStack(*route.MPLSDst)))
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}
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if route.NewDst != nil {
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if family != -1 && family != route.NewDst.Family() {
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return fmt.Errorf("new destination and destination are not the same address family")
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}
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buf, err := route.NewDst.Encode()
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if err != nil {
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return err
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}
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rtAttrs = append(rtAttrs, nl.NewRtAttr(nl.RTA_NEWDST, buf))
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}
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if route.Encap != nil {
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buf := make([]byte, 2)
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native.PutUint16(buf, uint16(route.Encap.Type()))
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rtAttrs = append(rtAttrs, nl.NewRtAttr(nl.RTA_ENCAP_TYPE, buf))
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buf, err := route.Encap.Encode()
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if err != nil {
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return err
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}
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rtAttrs = append(rtAttrs, nl.NewRtAttr(nl.RTA_ENCAP, buf))
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}
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if route.Src != nil {
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srcFamily := nl.GetIPFamily(route.Src)
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if family != -1 && family != srcFamily {
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return fmt.Errorf("source and destination ip are not the same IP family")
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}
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family = srcFamily
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var srcData []byte
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if srcFamily == FAMILY_V4 {
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srcData = route.Src.To4()
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} else {
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srcData = route.Src.To16()
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}
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// The commonly used src ip for routes is actually PREFSRC
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rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_PREFSRC, srcData))
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}
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if route.Gw != nil {
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gwFamily := nl.GetIPFamily(route.Gw)
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if family != -1 && family != gwFamily {
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return fmt.Errorf("gateway, source, and destination ip are not the same IP family")
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}
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family = gwFamily
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var gwData []byte
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if gwFamily == FAMILY_V4 {
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gwData = route.Gw.To4()
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} else {
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gwData = route.Gw.To16()
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}
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rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_GATEWAY, gwData))
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}
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if len(route.MultiPath) > 0 {
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buf := []byte{}
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for _, nh := range route.MultiPath {
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rtnh := &nl.RtNexthop{
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RtNexthop: syscall.RtNexthop{
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Hops: uint8(nh.Hops),
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Ifindex: int32(nh.LinkIndex),
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Flags: uint8(nh.Flags),
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},
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}
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children := []nl.NetlinkRequestData{}
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if nh.Gw != nil {
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gwFamily := nl.GetIPFamily(nh.Gw)
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if family != -1 && family != gwFamily {
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return fmt.Errorf("gateway, source, and destination ip are not the same IP family")
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}
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if gwFamily == FAMILY_V4 {
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children = append(children, nl.NewRtAttr(syscall.RTA_GATEWAY, []byte(nh.Gw.To4())))
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} else {
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children = append(children, nl.NewRtAttr(syscall.RTA_GATEWAY, []byte(nh.Gw.To16())))
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}
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}
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if nh.NewDst != nil {
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if family != -1 && family != nh.NewDst.Family() {
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return fmt.Errorf("new destination and destination are not the same address family")
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}
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buf, err := nh.NewDst.Encode()
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if err != nil {
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return err
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}
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children = append(children, nl.NewRtAttr(nl.RTA_NEWDST, buf))
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}
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if nh.Encap != nil {
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buf := make([]byte, 2)
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native.PutUint16(buf, uint16(nh.Encap.Type()))
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rtAttrs = append(rtAttrs, nl.NewRtAttr(nl.RTA_ENCAP_TYPE, buf))
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buf, err := nh.Encap.Encode()
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if err != nil {
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return err
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}
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children = append(children, nl.NewRtAttr(nl.RTA_ENCAP, buf))
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}
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rtnh.Children = children
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buf = append(buf, rtnh.Serialize()...)
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}
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rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_MULTIPATH, buf))
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}
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if route.Table > 0 {
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if route.Table >= 256 {
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msg.Table = syscall.RT_TABLE_UNSPEC
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b := make([]byte, 4)
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native.PutUint32(b, uint32(route.Table))
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rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_TABLE, b))
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} else {
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msg.Table = uint8(route.Table)
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}
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}
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if route.Priority > 0 {
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b := make([]byte, 4)
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native.PutUint32(b, uint32(route.Priority))
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rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_PRIORITY, b))
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}
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if route.Tos > 0 {
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msg.Tos = uint8(route.Tos)
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}
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if route.Protocol > 0 {
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msg.Protocol = uint8(route.Protocol)
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}
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if route.Type > 0 {
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msg.Type = uint8(route.Type)
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}
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msg.Flags = uint32(route.Flags)
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msg.Scope = uint8(route.Scope)
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msg.Family = uint8(family)
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req.AddData(msg)
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for _, attr := range rtAttrs {
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req.AddData(attr)
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}
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var (
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b = make([]byte, 4)
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native = nl.NativeEndian()
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)
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native.PutUint32(b, uint32(route.LinkIndex))
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req.AddData(nl.NewRtAttr(syscall.RTA_OIF, b))
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_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
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return err
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}
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// RouteList gets a list of routes in the system.
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// Equivalent to: `ip route show`.
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// The list can be filtered by link and ip family.
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func RouteList(link Link, family int) ([]Route, error) {
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return pkgHandle.RouteList(link, family)
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}
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// RouteList gets a list of routes in the system.
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// Equivalent to: `ip route show`.
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// The list can be filtered by link and ip family.
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func (h *Handle) RouteList(link Link, family int) ([]Route, error) {
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var routeFilter *Route
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if link != nil {
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routeFilter = &Route{
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LinkIndex: link.Attrs().Index,
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}
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}
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return h.RouteListFiltered(family, routeFilter, RT_FILTER_OIF)
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}
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// RouteListFiltered gets a list of routes in the system filtered with specified rules.
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// All rules must be defined in RouteFilter struct
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func RouteListFiltered(family int, filter *Route, filterMask uint64) ([]Route, error) {
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return pkgHandle.RouteListFiltered(family, filter, filterMask)
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}
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// RouteListFiltered gets a list of routes in the system filtered with specified rules.
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// All rules must be defined in RouteFilter struct
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func (h *Handle) RouteListFiltered(family int, filter *Route, filterMask uint64) ([]Route, error) {
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req := h.newNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_DUMP)
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infmsg := nl.NewIfInfomsg(family)
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req.AddData(infmsg)
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msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE)
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if err != nil {
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return nil, err
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}
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var res []Route
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for _, m := range msgs {
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msg := nl.DeserializeRtMsg(m)
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if msg.Flags&syscall.RTM_F_CLONED != 0 {
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// Ignore cloned routes
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continue
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}
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if msg.Table != syscall.RT_TABLE_MAIN {
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if filter == nil || filter != nil && filterMask&RT_FILTER_TABLE == 0 {
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// Ignore non-main tables
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continue
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}
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}
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route, err := deserializeRoute(m)
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if err != nil {
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return nil, err
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}
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if filter != nil {
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switch {
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case filterMask&RT_FILTER_TABLE != 0 && filter.Table != syscall.RT_TABLE_UNSPEC && route.Table != filter.Table:
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continue
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case filterMask&RT_FILTER_PROTOCOL != 0 && route.Protocol != filter.Protocol:
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continue
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case filterMask&RT_FILTER_SCOPE != 0 && route.Scope != filter.Scope:
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continue
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case filterMask&RT_FILTER_TYPE != 0 && route.Type != filter.Type:
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continue
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case filterMask&RT_FILTER_TOS != 0 && route.Tos != filter.Tos:
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continue
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case filterMask&RT_FILTER_OIF != 0 && route.LinkIndex != filter.LinkIndex:
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continue
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case filterMask&RT_FILTER_IIF != 0 && route.ILinkIndex != filter.ILinkIndex:
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continue
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case filterMask&RT_FILTER_GW != 0 && !route.Gw.Equal(filter.Gw):
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continue
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case filterMask&RT_FILTER_SRC != 0 && !route.Src.Equal(filter.Src):
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continue
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case filterMask&RT_FILTER_DST != 0:
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if filter.MPLSDst == nil || route.MPLSDst == nil || (*filter.MPLSDst) != (*route.MPLSDst) {
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if filter.Dst == nil {
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if route.Dst != nil {
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continue
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}
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} else {
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if route.Dst == nil {
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continue
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}
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aMaskLen, aMaskBits := route.Dst.Mask.Size()
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bMaskLen, bMaskBits := filter.Dst.Mask.Size()
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if !(route.Dst.IP.Equal(filter.Dst.IP) && aMaskLen == bMaskLen && aMaskBits == bMaskBits) {
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continue
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}
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}
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}
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}
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}
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res = append(res, route)
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}
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return res, nil
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}
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// deserializeRoute decodes a binary netlink message into a Route struct
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func deserializeRoute(m []byte) (Route, error) {
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msg := nl.DeserializeRtMsg(m)
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attrs, err := nl.ParseRouteAttr(m[msg.Len():])
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if err != nil {
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return Route{}, err
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}
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route := Route{
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Scope: Scope(msg.Scope),
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Protocol: int(msg.Protocol),
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Table: int(msg.Table),
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Type: int(msg.Type),
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Tos: int(msg.Tos),
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Flags: int(msg.Flags),
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}
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native := nl.NativeEndian()
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var encap, encapType syscall.NetlinkRouteAttr
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for _, attr := range attrs {
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switch attr.Attr.Type {
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case syscall.RTA_GATEWAY:
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route.Gw = net.IP(attr.Value)
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case syscall.RTA_PREFSRC:
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route.Src = net.IP(attr.Value)
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case syscall.RTA_DST:
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if msg.Family == nl.FAMILY_MPLS {
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stack := nl.DecodeMPLSStack(attr.Value)
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if len(stack) == 0 || len(stack) > 1 {
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return route, fmt.Errorf("invalid MPLS RTA_DST")
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}
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route.MPLSDst = &stack[0]
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} else {
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route.Dst = &net.IPNet{
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IP: attr.Value,
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Mask: net.CIDRMask(int(msg.Dst_len), 8*len(attr.Value)),
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}
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}
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case syscall.RTA_OIF:
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route.LinkIndex = int(native.Uint32(attr.Value[0:4]))
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case syscall.RTA_IIF:
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route.ILinkIndex = int(native.Uint32(attr.Value[0:4]))
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case syscall.RTA_PRIORITY:
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route.Priority = int(native.Uint32(attr.Value[0:4]))
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case syscall.RTA_TABLE:
|
|
route.Table = int(native.Uint32(attr.Value[0:4]))
|
|
case syscall.RTA_MULTIPATH:
|
|
parseRtNexthop := func(value []byte) (*NexthopInfo, []byte, error) {
|
|
if len(value) < syscall.SizeofRtNexthop {
|
|
return nil, nil, fmt.Errorf("Lack of bytes")
|
|
}
|
|
nh := nl.DeserializeRtNexthop(value)
|
|
if len(value) < int(nh.RtNexthop.Len) {
|
|
return nil, nil, fmt.Errorf("Lack of bytes")
|
|
}
|
|
info := &NexthopInfo{
|
|
LinkIndex: int(nh.RtNexthop.Ifindex),
|
|
Hops: int(nh.RtNexthop.Hops),
|
|
Flags: int(nh.RtNexthop.Flags),
|
|
}
|
|
attrs, err := nl.ParseRouteAttr(value[syscall.SizeofRtNexthop:int(nh.RtNexthop.Len)])
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
var encap, encapType syscall.NetlinkRouteAttr
|
|
for _, attr := range attrs {
|
|
switch attr.Attr.Type {
|
|
case syscall.RTA_GATEWAY:
|
|
info.Gw = net.IP(attr.Value)
|
|
case nl.RTA_NEWDST:
|
|
var d Destination
|
|
switch msg.Family {
|
|
case nl.FAMILY_MPLS:
|
|
d = &MPLSDestination{}
|
|
}
|
|
if err := d.Decode(attr.Value); err != nil {
|
|
return nil, nil, err
|
|
}
|
|
info.NewDst = d
|
|
case nl.RTA_ENCAP_TYPE:
|
|
encapType = attr
|
|
case nl.RTA_ENCAP:
|
|
encap = attr
|
|
}
|
|
}
|
|
|
|
if len(encap.Value) != 0 && len(encapType.Value) != 0 {
|
|
typ := int(native.Uint16(encapType.Value[0:2]))
|
|
var e Encap
|
|
switch typ {
|
|
case nl.LWTUNNEL_ENCAP_MPLS:
|
|
e = &MPLSEncap{}
|
|
if err := e.Decode(encap.Value); err != nil {
|
|
return nil, nil, err
|
|
}
|
|
}
|
|
info.Encap = e
|
|
}
|
|
|
|
return info, value[int(nh.RtNexthop.Len):], nil
|
|
}
|
|
rest := attr.Value
|
|
for len(rest) > 0 {
|
|
info, buf, err := parseRtNexthop(rest)
|
|
if err != nil {
|
|
return route, err
|
|
}
|
|
route.MultiPath = append(route.MultiPath, info)
|
|
rest = buf
|
|
}
|
|
case nl.RTA_NEWDST:
|
|
var d Destination
|
|
switch msg.Family {
|
|
case nl.FAMILY_MPLS:
|
|
d = &MPLSDestination{}
|
|
}
|
|
if err := d.Decode(attr.Value); err != nil {
|
|
return route, err
|
|
}
|
|
route.NewDst = d
|
|
case nl.RTA_ENCAP_TYPE:
|
|
encapType = attr
|
|
case nl.RTA_ENCAP:
|
|
encap = attr
|
|
}
|
|
}
|
|
|
|
if len(encap.Value) != 0 && len(encapType.Value) != 0 {
|
|
typ := int(native.Uint16(encapType.Value[0:2]))
|
|
var e Encap
|
|
switch typ {
|
|
case nl.LWTUNNEL_ENCAP_MPLS:
|
|
e = &MPLSEncap{}
|
|
if err := e.Decode(encap.Value); err != nil {
|
|
return route, err
|
|
}
|
|
}
|
|
route.Encap = e
|
|
}
|
|
|
|
return route, nil
|
|
}
|
|
|
|
// RouteGet gets a route to a specific destination from the host system.
|
|
// Equivalent to: 'ip route get'.
|
|
func RouteGet(destination net.IP) ([]Route, error) {
|
|
return pkgHandle.RouteGet(destination)
|
|
}
|
|
|
|
// RouteGet gets a route to a specific destination from the host system.
|
|
// Equivalent to: 'ip route get'.
|
|
func (h *Handle) RouteGet(destination net.IP) ([]Route, error) {
|
|
req := h.newNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_REQUEST)
|
|
family := nl.GetIPFamily(destination)
|
|
var destinationData []byte
|
|
var bitlen uint8
|
|
if family == FAMILY_V4 {
|
|
destinationData = destination.To4()
|
|
bitlen = 32
|
|
} else {
|
|
destinationData = destination.To16()
|
|
bitlen = 128
|
|
}
|
|
msg := &nl.RtMsg{}
|
|
msg.Family = uint8(family)
|
|
msg.Dst_len = bitlen
|
|
req.AddData(msg)
|
|
|
|
rtaDst := nl.NewRtAttr(syscall.RTA_DST, destinationData)
|
|
req.AddData(rtaDst)
|
|
|
|
msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var res []Route
|
|
for _, m := range msgs {
|
|
route, err := deserializeRoute(m)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
res = append(res, route)
|
|
}
|
|
return res, nil
|
|
|
|
}
|
|
|
|
// RouteSubscribe takes a chan down which notifications will be sent
|
|
// when routes are added or deleted. Close the 'done' chan to stop subscription.
|
|
func RouteSubscribe(ch chan<- RouteUpdate, done <-chan struct{}) error {
|
|
return routeSubscribeAt(netns.None(), netns.None(), ch, done)
|
|
}
|
|
|
|
// RouteSubscribeAt works like RouteSubscribe plus it allows the caller
|
|
// to choose the network namespace in which to subscribe (ns).
|
|
func RouteSubscribeAt(ns netns.NsHandle, ch chan<- RouteUpdate, done <-chan struct{}) error {
|
|
return routeSubscribeAt(ns, netns.None(), ch, done)
|
|
}
|
|
|
|
func routeSubscribeAt(newNs, curNs netns.NsHandle, ch chan<- RouteUpdate, done <-chan struct{}) error {
|
|
s, err := nl.SubscribeAt(newNs, curNs, syscall.NETLINK_ROUTE, syscall.RTNLGRP_IPV4_ROUTE, syscall.RTNLGRP_IPV6_ROUTE)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if done != nil {
|
|
go func() {
|
|
<-done
|
|
s.Close()
|
|
}()
|
|
}
|
|
go func() {
|
|
defer close(ch)
|
|
for {
|
|
msgs, err := s.Receive()
|
|
if err != nil {
|
|
return
|
|
}
|
|
for _, m := range msgs {
|
|
route, err := deserializeRoute(m.Data)
|
|
if err != nil {
|
|
return
|
|
}
|
|
ch <- RouteUpdate{Type: m.Header.Type, Route: route}
|
|
}
|
|
}
|
|
}()
|
|
|
|
return nil
|
|
}
|