435 lines
11 KiB
Go
435 lines
11 KiB
Go
package netlink
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import (
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"fmt"
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"net"
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"syscall"
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"unsafe"
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"github.com/vishvananda/netlink/nl"
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"github.com/vishvananda/netns"
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"golang.org/x/sys/unix"
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)
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const (
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NDA_UNSPEC = iota
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NDA_DST
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NDA_LLADDR
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NDA_CACHEINFO
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NDA_PROBES
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NDA_VLAN
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NDA_PORT
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NDA_VNI
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NDA_IFINDEX
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NDA_MASTER
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NDA_LINK_NETNSID
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NDA_SRC_VNI
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NDA_MAX = NDA_SRC_VNI
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)
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// Neighbor Cache Entry States.
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const (
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NUD_NONE = 0x00
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NUD_INCOMPLETE = 0x01
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NUD_REACHABLE = 0x02
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NUD_STALE = 0x04
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NUD_DELAY = 0x08
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NUD_PROBE = 0x10
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NUD_FAILED = 0x20
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NUD_NOARP = 0x40
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NUD_PERMANENT = 0x80
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)
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// Neighbor Flags
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const (
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NTF_USE = 0x01
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NTF_SELF = 0x02
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NTF_MASTER = 0x04
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NTF_PROXY = 0x08
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NTF_ROUTER = 0x80
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)
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// Ndmsg is for adding, removing or receiving information about a neighbor table entry
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type Ndmsg struct {
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Family uint8
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Index uint32
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State uint16
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Flags uint8
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Type uint8
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}
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func deserializeNdmsg(b []byte) *Ndmsg {
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var dummy Ndmsg
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return (*Ndmsg)(unsafe.Pointer(&b[0:unsafe.Sizeof(dummy)][0]))
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}
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func (msg *Ndmsg) Serialize() []byte {
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return (*(*[unsafe.Sizeof(*msg)]byte)(unsafe.Pointer(msg)))[:]
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}
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func (msg *Ndmsg) Len() int {
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return int(unsafe.Sizeof(*msg))
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}
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// NeighAdd will add an IP to MAC mapping to the ARP table
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// Equivalent to: `ip neigh add ....`
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func NeighAdd(neigh *Neigh) error {
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return pkgHandle.NeighAdd(neigh)
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}
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// NeighAdd will add an IP to MAC mapping to the ARP table
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// Equivalent to: `ip neigh add ....`
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func (h *Handle) NeighAdd(neigh *Neigh) error {
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return h.neighAdd(neigh, unix.NLM_F_CREATE|unix.NLM_F_EXCL)
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}
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// NeighSet will add or replace an IP to MAC mapping to the ARP table
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// Equivalent to: `ip neigh replace....`
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func NeighSet(neigh *Neigh) error {
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return pkgHandle.NeighSet(neigh)
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}
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// NeighSet will add or replace an IP to MAC mapping to the ARP table
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// Equivalent to: `ip neigh replace....`
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func (h *Handle) NeighSet(neigh *Neigh) error {
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return h.neighAdd(neigh, unix.NLM_F_CREATE|unix.NLM_F_REPLACE)
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}
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// NeighAppend will append an entry to FDB
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// Equivalent to: `bridge fdb append...`
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func NeighAppend(neigh *Neigh) error {
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return pkgHandle.NeighAppend(neigh)
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}
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// NeighAppend will append an entry to FDB
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// Equivalent to: `bridge fdb append...`
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func (h *Handle) NeighAppend(neigh *Neigh) error {
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return h.neighAdd(neigh, unix.NLM_F_CREATE|unix.NLM_F_APPEND)
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}
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// NeighAppend will append an entry to FDB
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// Equivalent to: `bridge fdb append...`
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func neighAdd(neigh *Neigh, mode int) error {
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return pkgHandle.neighAdd(neigh, mode)
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}
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// NeighAppend will append an entry to FDB
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// Equivalent to: `bridge fdb append...`
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func (h *Handle) neighAdd(neigh *Neigh, mode int) error {
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req := h.newNetlinkRequest(unix.RTM_NEWNEIGH, mode|unix.NLM_F_ACK)
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return neighHandle(neigh, req)
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}
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// NeighDel will delete an IP address from a link device.
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// Equivalent to: `ip addr del $addr dev $link`
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func NeighDel(neigh *Neigh) error {
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return pkgHandle.NeighDel(neigh)
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}
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// NeighDel will delete an IP address from a link device.
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// Equivalent to: `ip addr del $addr dev $link`
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func (h *Handle) NeighDel(neigh *Neigh) error {
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req := h.newNetlinkRequest(unix.RTM_DELNEIGH, unix.NLM_F_ACK)
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return neighHandle(neigh, req)
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}
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func neighHandle(neigh *Neigh, req *nl.NetlinkRequest) error {
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var family int
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if neigh.Family > 0 {
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family = neigh.Family
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} else {
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family = nl.GetIPFamily(neigh.IP)
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}
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msg := Ndmsg{
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Family: uint8(family),
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Index: uint32(neigh.LinkIndex),
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State: uint16(neigh.State),
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Type: uint8(neigh.Type),
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Flags: uint8(neigh.Flags),
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}
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req.AddData(&msg)
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ipData := neigh.IP.To4()
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if ipData == nil {
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ipData = neigh.IP.To16()
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}
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dstData := nl.NewRtAttr(NDA_DST, ipData)
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req.AddData(dstData)
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if neigh.LLIPAddr != nil {
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llIPData := nl.NewRtAttr(NDA_LLADDR, neigh.LLIPAddr.To4())
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req.AddData(llIPData)
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} else if neigh.Flags != NTF_PROXY || neigh.HardwareAddr != nil {
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hwData := nl.NewRtAttr(NDA_LLADDR, []byte(neigh.HardwareAddr))
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req.AddData(hwData)
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}
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if neigh.Vlan != 0 {
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vlanData := nl.NewRtAttr(NDA_VLAN, nl.Uint16Attr(uint16(neigh.Vlan)))
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req.AddData(vlanData)
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}
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if neigh.VNI != 0 {
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vniData := nl.NewRtAttr(NDA_VNI, nl.Uint32Attr(uint32(neigh.VNI)))
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req.AddData(vniData)
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}
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if neigh.MasterIndex != 0 {
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masterData := nl.NewRtAttr(NDA_MASTER, nl.Uint32Attr(uint32(neigh.MasterIndex)))
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req.AddData(masterData)
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}
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_, err := req.Execute(unix.NETLINK_ROUTE, 0)
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return err
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}
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// NeighList returns a list of IP-MAC mappings in the system (ARP table).
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// Equivalent to: `ip neighbor show`.
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// The list can be filtered by link and ip family.
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func NeighList(linkIndex, family int) ([]Neigh, error) {
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return pkgHandle.NeighList(linkIndex, family)
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}
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// NeighProxyList returns a list of neighbor proxies in the system.
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// Equivalent to: `ip neighbor show proxy`.
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// The list can be filtered by link and ip family.
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func NeighProxyList(linkIndex, family int) ([]Neigh, error) {
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return pkgHandle.NeighProxyList(linkIndex, family)
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}
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// NeighList returns a list of IP-MAC mappings in the system (ARP table).
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// Equivalent to: `ip neighbor show`.
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// The list can be filtered by link and ip family.
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func (h *Handle) NeighList(linkIndex, family int) ([]Neigh, error) {
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return h.NeighListExecute(Ndmsg{
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Family: uint8(family),
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Index: uint32(linkIndex),
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})
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}
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// NeighProxyList returns a list of neighbor proxies in the system.
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// Equivalent to: `ip neighbor show proxy`.
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// The list can be filtered by link, ip family.
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func (h *Handle) NeighProxyList(linkIndex, family int) ([]Neigh, error) {
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return h.NeighListExecute(Ndmsg{
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Family: uint8(family),
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Index: uint32(linkIndex),
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Flags: NTF_PROXY,
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})
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}
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// NeighListExecute returns a list of neighbour entries filtered by link, ip family, flag and state.
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func NeighListExecute(msg Ndmsg) ([]Neigh, error) {
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return pkgHandle.NeighListExecute(msg)
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}
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// NeighListExecute returns a list of neighbour entries filtered by link, ip family, flag and state.
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func (h *Handle) NeighListExecute(msg Ndmsg) ([]Neigh, error) {
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req := h.newNetlinkRequest(unix.RTM_GETNEIGH, unix.NLM_F_DUMP)
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req.AddData(&msg)
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msgs, err := req.Execute(unix.NETLINK_ROUTE, unix.RTM_NEWNEIGH)
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if err != nil {
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return nil, err
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}
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var res []Neigh
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for _, m := range msgs {
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ndm := deserializeNdmsg(m)
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if msg.Index != 0 && ndm.Index != msg.Index {
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// Ignore messages from other interfaces
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continue
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}
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if msg.Family != 0 && ndm.Family != msg.Family {
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continue
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}
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if msg.State != 0 && ndm.State != msg.State {
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continue
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}
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if msg.Type != 0 && ndm.Type != msg.Type {
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continue
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}
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if msg.Flags != 0 && ndm.Flags != msg.Flags {
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continue
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}
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neigh, err := NeighDeserialize(m)
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if err != nil {
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continue
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}
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res = append(res, *neigh)
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}
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return res, nil
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}
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func NeighDeserialize(m []byte) (*Neigh, error) {
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msg := deserializeNdmsg(m)
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neigh := Neigh{
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LinkIndex: int(msg.Index),
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Family: int(msg.Family),
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State: int(msg.State),
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Type: int(msg.Type),
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Flags: int(msg.Flags),
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}
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attrs, err := nl.ParseRouteAttr(m[msg.Len():])
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if err != nil {
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return nil, err
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}
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for _, attr := range attrs {
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switch attr.Attr.Type {
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case NDA_DST:
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neigh.IP = net.IP(attr.Value)
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case NDA_LLADDR:
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// BUG: Is this a bug in the netlink library?
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// #define RTA_LENGTH(len) (RTA_ALIGN(sizeof(struct rtattr)) + (len))
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// #define RTA_PAYLOAD(rta) ((int)((rta)->rta_len) - RTA_LENGTH(0))
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attrLen := attr.Attr.Len - unix.SizeofRtAttr
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if attrLen == 4 {
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neigh.LLIPAddr = net.IP(attr.Value)
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} else if attrLen == 16 {
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// Can be IPv6 or FireWire HWAddr
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link, err := LinkByIndex(neigh.LinkIndex)
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if err == nil && link.Attrs().EncapType == "tunnel6" {
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neigh.IP = net.IP(attr.Value)
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} else {
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neigh.HardwareAddr = net.HardwareAddr(attr.Value)
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}
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} else {
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neigh.HardwareAddr = net.HardwareAddr(attr.Value)
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}
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case NDA_VLAN:
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neigh.Vlan = int(native.Uint16(attr.Value[0:2]))
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case NDA_VNI:
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neigh.VNI = int(native.Uint32(attr.Value[0:4]))
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case NDA_MASTER:
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neigh.MasterIndex = int(native.Uint32(attr.Value[0:4]))
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}
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}
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return &neigh, nil
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}
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// NeighSubscribe takes a chan down which notifications will be sent
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// when neighbors are added or deleted. Close the 'done' chan to stop subscription.
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func NeighSubscribe(ch chan<- NeighUpdate, done <-chan struct{}) error {
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return neighSubscribeAt(netns.None(), netns.None(), ch, done, nil, false)
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}
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// NeighSubscribeAt works like NeighSubscribe plus it allows the caller
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// to choose the network namespace in which to subscribe (ns).
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func NeighSubscribeAt(ns netns.NsHandle, ch chan<- NeighUpdate, done <-chan struct{}) error {
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return neighSubscribeAt(ns, netns.None(), ch, done, nil, false)
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}
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// NeighSubscribeOptions contains a set of options to use with
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// NeighSubscribeWithOptions.
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type NeighSubscribeOptions struct {
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Namespace *netns.NsHandle
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ErrorCallback func(error)
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ListExisting bool
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}
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// NeighSubscribeWithOptions work like NeighSubscribe but enable to
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// provide additional options to modify the behavior. Currently, the
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// namespace can be provided as well as an error callback.
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func NeighSubscribeWithOptions(ch chan<- NeighUpdate, done <-chan struct{}, options NeighSubscribeOptions) error {
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if options.Namespace == nil {
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none := netns.None()
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options.Namespace = &none
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}
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return neighSubscribeAt(*options.Namespace, netns.None(), ch, done, options.ErrorCallback, options.ListExisting)
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}
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func neighSubscribeAt(newNs, curNs netns.NsHandle, ch chan<- NeighUpdate, done <-chan struct{}, cberr func(error), listExisting bool) error {
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s, err := nl.SubscribeAt(newNs, curNs, unix.NETLINK_ROUTE, unix.RTNLGRP_NEIGH)
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makeRequest := func(family int) error {
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req := pkgHandle.newNetlinkRequest(unix.RTM_GETNEIGH,
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unix.NLM_F_DUMP)
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infmsg := nl.NewIfInfomsg(family)
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req.AddData(infmsg)
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if err := s.Send(req); err != nil {
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return err
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}
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return nil
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}
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if err != nil {
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return err
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}
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if done != nil {
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go func() {
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<-done
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s.Close()
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}()
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}
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if listExisting {
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if err := makeRequest(unix.AF_UNSPEC); err != nil {
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return err
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}
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// We have to wait for NLMSG_DONE before making AF_BRIDGE request
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}
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go func() {
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defer close(ch)
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for {
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msgs, from, err := s.Receive()
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if err != nil {
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if cberr != nil {
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cberr(err)
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}
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return
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}
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if from.Pid != nl.PidKernel {
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if cberr != nil {
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cberr(fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, nl.PidKernel))
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}
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continue
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}
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for _, m := range msgs {
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if m.Header.Type == unix.NLMSG_DONE {
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if listExisting {
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// This will be called after handling AF_UNSPEC
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// list request, we have to wait for NLMSG_DONE
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// before making another request
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if err := makeRequest(unix.AF_BRIDGE); err != nil {
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if cberr != nil {
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cberr(err)
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}
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return
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}
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listExisting = false
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}
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continue
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}
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if m.Header.Type == unix.NLMSG_ERROR {
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native := nl.NativeEndian()
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error := int32(native.Uint32(m.Data[0:4]))
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if error == 0 {
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continue
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}
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if cberr != nil {
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cberr(syscall.Errno(-error))
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}
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return
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}
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neigh, err := NeighDeserialize(m.Data)
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if err != nil {
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if cberr != nil {
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cberr(err)
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}
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return
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}
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ch <- NeighUpdate{Type: m.Header.Type, Neigh: *neigh}
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}
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}
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}()
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return nil
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}
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