334 lines
10 KiB
Go
334 lines
10 KiB
Go
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package tenus
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import (
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"fmt"
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"net"
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"os"
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"syscall"
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"github.com/docker/libcontainer/netlink"
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"github.com/docker/libcontainer/system"
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)
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// LinkOptions allows you to specify network link options.
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type LinkOptions struct {
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// MAC address
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MacAddr string
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// Maximum Transmission Unit
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MTU int
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// Link network flags i.e. FlagUp, FlagLoopback, FlagMulticast
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Flags net.Flags
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// Network namespace in which the network link should be created
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Ns int
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}
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// Linker is a generic Linux network link
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type Linker interface {
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// NetInterface returns the link's logical network interface
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NetInterface() *net.Interface
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// DeleteLink deletes the link from Linux host
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DeleteLink() error
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// SetLinkMTU sets the link's MTU.
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SetLinkMTU(int) error
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// SetLinkMacAddress sets the link's MAC address.
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SetLinkMacAddress(string) error
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// SetLinkUp brings the link up
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SetLinkUp() error
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// SetLinkDown brings the link down
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SetLinkDown() error
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// SetLinkIp configures the link's IP address
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SetLinkIp(net.IP, *net.IPNet) error
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// UnsetLinkIp remove and IP address from the link
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UnsetLinkIp(net.IP, *net.IPNet) error
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// SetLinkDefaultGw configures the link's default gateway
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SetLinkDefaultGw(*net.IP) error
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// SetLinkNetNsPid moves the link to network namespace specified by PID
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SetLinkNetNsPid(int) error
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// SetLinkNetInNs configures network settings of the link in network namespace
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SetLinkNetInNs(int, net.IP, *net.IPNet, *net.IP) error
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}
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// Link has a logical network interface
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type Link struct {
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ifc *net.Interface
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}
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// NewLink creates new network link on Linux host.
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//
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// It is equivalent of running: ip link add name ${ifcName} type dummy
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// NewLink returns Linker which is initialized to a pointer of type Link if the
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// link was created successfully on the Linux host.
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// It returns error if the network link could not be created on Linux host.
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func NewLink(ifcName string) (Linker, error) {
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if ok, err := NetInterfaceNameValid(ifcName); !ok {
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return nil, err
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}
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if _, err := net.InterfaceByName(ifcName); err == nil {
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return nil, fmt.Errorf("Interface name %s already assigned on the host", ifcName)
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}
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if err := netlink.NetworkLinkAdd(ifcName, "dummy"); err != nil {
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return nil, fmt.Errorf("Could not create new link %s: %s", ifcName, err)
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}
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newIfc, err := net.InterfaceByName(ifcName)
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if err != nil {
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return nil, fmt.Errorf("Could not find the new interface: %s", err)
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}
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return &Link{
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ifc: newIfc,
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}, nil
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}
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// NewLinkFrom creates new tenus link on Linux host from an existing interface of given name
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func NewLinkFrom(ifcName string) (Linker, error) {
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if ok, err := NetInterfaceNameValid(ifcName); !ok {
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return nil, err
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}
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newIfc, err := net.InterfaceByName(ifcName)
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if err != nil {
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return nil, fmt.Errorf("Could not find the new interface: %s", err)
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}
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return &Link{
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ifc: newIfc,
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}, nil
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}
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// NewLinkWithOptions creates new network link on Linux host and sets some of its network
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// parameters passed in as LinkOptions
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//
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// Calling NewLinkWithOptions is equivalent of running following commands one after another if
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// particular option is passed in as a parameter:
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// ip link add name ${ifcName} type dummy
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// ip link set dev ${ifcName} address ${MAC address}
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// ip link set dev ${ifcName} mtu ${MTU value}
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// ip link set dev ${ifcName} up
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// NewLinkWithOptions returns Linker which is initialized to a pointer of type Link if the network
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// link with given LinkOptions was created successfully on the Linux host.
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// It attempts to delete the link if any of the LinkOptions are incorrect or if setting the options
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// failed and returns error.
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func NewLinkWithOptions(ifcName string, opts LinkOptions) (Linker, error) {
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if ok, err := NetInterfaceNameValid(ifcName); !ok {
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return nil, err
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}
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if _, err := net.InterfaceByName(ifcName); err == nil {
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return nil, fmt.Errorf("Interface name %s already assigned on the host", ifcName)
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}
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if err := netlink.NetworkLinkAdd(ifcName, "dummy"); err != nil {
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return nil, fmt.Errorf("Could not create new link %s: %s", ifcName, err)
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}
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newIfc, err := net.InterfaceByName(ifcName)
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if err != nil {
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return nil, fmt.Errorf("Could not find the new interface: %s", err)
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}
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if (opts != LinkOptions{}) {
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errOpts := setLinkOptions(newIfc, opts)
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if errOpts != nil {
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if errDel := DeleteLink(newIfc.Name); err != nil {
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return nil, fmt.Errorf("Incorrect options specified: %s. Attempt to delete the link failed: %s",
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errOpts, errDel)
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}
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return nil, fmt.Errorf("Could not set link options: %s", errOpts)
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}
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}
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return &Link{
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ifc: newIfc,
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}, nil
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}
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// DeleteLink deletes netowrk link from Linux Host
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// It is equivalent of running: ip link delete dev ${name}
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func DeleteLink(name string) error {
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return netlink.NetworkLinkDel(name)
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}
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// NetInterface returns link's logical network interface.
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func (l *Link) NetInterface() *net.Interface {
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return l.ifc
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}
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// DeleteLink deletes link interface on Linux host.
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// It is equivalent of running: ip link delete dev ${interface name}
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func (l *Link) DeleteLink() error {
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return netlink.NetworkLinkDel(l.NetInterface().Name)
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}
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// SetLinkMTU sets link's MTU.
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// It is equivalent of running: ip link set dev ${interface name} mtu ${MTU value}
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func (l *Link) SetLinkMTU(mtu int) error {
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return netlink.NetworkSetMTU(l.NetInterface(), mtu)
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}
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// SetLinkMacAddress sets link's MAC address.
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// It is equivalent of running: ip link set dev ${interface name} address ${address}
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func (l *Link) SetLinkMacAddress(macaddr string) error {
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return netlink.NetworkSetMacAddress(l.NetInterface(), macaddr)
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}
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// SetLinkUp brings the link up.
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// It is equivalent of running: ip link set dev ${interface name} up
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func (l *Link) SetLinkUp() error {
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return netlink.NetworkLinkUp(l.NetInterface())
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}
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// SetLinkDown brings the link down.
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// It is equivalent of running: ip link set dev ${interface name} down
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func (l *Link) SetLinkDown() error {
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return netlink.NetworkLinkDown(l.NetInterface())
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}
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// SetLinkIp configures the link's IP address.
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// It is equivalent of running: ip address add ${address}/${mask} dev ${interface name}
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func (l *Link) SetLinkIp(ip net.IP, network *net.IPNet) error {
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return netlink.NetworkLinkAddIp(l.NetInterface(), ip, network)
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}
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// UnsetLinkIp configures the link's IP address.
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// It is equivalent of running: ip address del ${address}/${mask} dev ${interface name}
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func (l *Link) UnsetLinkIp(ip net.IP, network *net.IPNet) error {
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return netlink.NetworkLinkDelIp(l.NetInterface(), ip, network)
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}
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// SetLinkDefaultGw configures the link's default Gateway.
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// It is equivalent of running: ip route add default via ${ip address}
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func (l *Link) SetLinkDefaultGw(gw *net.IP) error {
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return netlink.AddDefaultGw(gw.String(), l.NetInterface().Name)
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}
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// SetLinkNetNsPid moves the link to Network namespace specified by PID.
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func (l *Link) SetLinkNetNsPid(nspid int) error {
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return netlink.NetworkSetNsPid(l.NetInterface(), nspid)
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}
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// SetLinkNetInNs configures network settings of the link in network namespace specified by PID.
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func (l *Link) SetLinkNetInNs(nspid int, ip net.IP, network *net.IPNet, gw *net.IP) error {
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origNs, _ := NetNsHandle(os.Getpid())
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defer syscall.Close(int(origNs))
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defer system.Setns(origNs, syscall.CLONE_NEWNET)
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if err := SetNetNsToPid(nspid); err != nil {
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return fmt.Errorf("Setting network namespace failed: %s", err)
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}
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if err := netlink.NetworkLinkAddIp(l.NetInterface(), ip, network); err != nil {
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return fmt.Errorf("Unable to set IP: %s in pid: %d network namespace", ip.String(), nspid)
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}
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if err := netlink.NetworkLinkUp(l.ifc); err != nil {
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return fmt.Errorf("Unable to bring %s interface UP: %d", l.ifc.Name, nspid)
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}
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if gw != nil {
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if err := netlink.AddDefaultGw(gw.String(), l.NetInterface().Name); err != nil {
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return fmt.Errorf("Unable to set Default gateway: %s in pid: %d network namespace", gw.String(), nspid)
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}
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}
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return nil
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}
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// SetLinkNsFd sets the link's Linux namespace to the one specified by filesystem path.
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func (l *Link) SetLinkNsFd(nspath string) error {
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fd, err := syscall.Open(nspath, syscall.O_RDONLY, 0)
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if err != nil {
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return fmt.Errorf("Could not attach to Network namespace: %s", err)
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}
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return netlink.NetworkSetNsFd(l.NetInterface(), fd)
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}
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// SetLinkNsToDocker sets the link's Linux namespace to a running Docker one specified by Docker name.
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func (l *Link) SetLinkNsToDocker(name string, dockerHost string) error {
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pid, err := DockerPidByName(name, dockerHost)
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if err != nil {
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return fmt.Errorf("Failed to find docker %s : %s", name, err)
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}
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return l.SetLinkNetNsPid(pid)
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}
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// RenameInterfaceByName renames an interface of given name.
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func RenameInterfaceByName(old string, newName string) error {
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iface, err := net.InterfaceByName(old)
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if err != nil {
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return err
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}
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return netlink.NetworkChangeName(iface, newName)
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}
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// setLinkOptions validates and sets link's various options passed in as LinkOptions.
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func setLinkOptions(ifc *net.Interface, opts LinkOptions) error {
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macaddr, mtu, flags, ns := opts.MacAddr, opts.MTU, opts.Flags, opts.Ns
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// if MTU is passed in LinkOptions
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if mtu != 0 {
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if err := validMtu(mtu); err != nil {
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return err
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}
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if err := netlink.NetworkSetMTU(ifc, mtu); err != nil {
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return fmt.Errorf("Unable to set MTU: %s", err)
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}
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}
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// if MacAddress is passed in LinkOptions
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if macaddr != "" {
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if err := validMacAddress(macaddr); err != nil {
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return err
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}
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if err := netlink.NetworkSetMacAddress(ifc, macaddr); err != nil {
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return fmt.Errorf("Unable to set MAC Address: %s", err)
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}
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}
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// if ns is passed in LinkOptions
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if ns != 0 {
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if err := validNs(ns); err != nil {
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return err
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}
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if err := netlink.NetworkSetNsPid(ifc, ns); err != nil {
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return fmt.Errorf("Unable to set Network namespace: %s", err)
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}
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}
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// if flags is passed in LinkOptions
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if flags != 0 {
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if err := validFlags(flags); err != nil {
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return err
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}
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if ns != 0 && (ns != 1 || ns != os.Getpid()) {
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if (flags & syscall.IFF_UP) == syscall.IFF_UP {
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origNs, _ := NetNsHandle(os.Getpid())
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defer syscall.Close(int(origNs))
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defer system.Setns(origNs, syscall.CLONE_NEWNET)
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if err := SetNetNsToPid(ns); err != nil {
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return fmt.Errorf("Switching to %d network namespace failed: %s", ns, err)
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}
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if err := netlink.NetworkLinkUp(ifc); err != nil {
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return fmt.Errorf("Unable to bring %s interface UP: %d", ifc.Name, ns)
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}
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}
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} else {
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if err := netlink.NetworkLinkUp(ifc); err != nil {
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return fmt.Errorf("Could not bring up network link %s: %s", ifc.Name, err)
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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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