zoreide/vendor/github.com/milosgajdos/tenus/veth_linux.go

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2022-07-01 09:46:31 -04:00
package tenus
import (
"fmt"
"net"
"os"
"syscall"
"github.com/docker/libcontainer/netlink"
"github.com/docker/libcontainer/system"
)
// VethOptions allows you to specify options for veth link.
type VethOptions struct {
// Veth pair's peer interface name
PeerName string
// TX queue length
TxQueueLen int
}
// Vether embeds Linker interface and adds few more functions mostly to handle peer link interface
type Vether interface {
// Linker interface
Linker
// PeerNetInterface returns peer network interface
PeerNetInterface() *net.Interface
// SetPeerLinkUp sets peer link up - which also brings up the other peer in VethPair
SetPeerLinkUp() error
// DeletePeerLink deletes peer link - this also deletes the other peer in VethPair
DeletePeerLink() error
// SetPeerLinkIp configures peer link's IP address
SetPeerLinkIp(net.IP, *net.IPNet) error
// SetPeerLinkNsToDocker sends peer link into Docker
SetPeerLinkNsToDocker(string, string) error
// SetPeerLinkNsPid sends peer link into container specified by PID
SetPeerLinkNsPid(int) error
// SetPeerLinkNsFd sends peer link into container specified by path
SetPeerLinkNsFd(string) error
// SetPeerLinkNetInNs configures peer link's IP network in network namespace specified by PID
SetPeerLinkNetInNs(int, net.IP, *net.IPNet, *net.IP) error
}
// VethPair is a Link. Veth links are created in pairs called peers.
type VethPair struct {
Link
// Peer network interface
peerIfc *net.Interface
}
// NewVethPair creates a pair of veth network links.
//
// It is equivalent of running:
// ip link add name veth${RANDOM STRING} type veth peer name veth${RANDOM STRING}.
// NewVethPair returns Vether which is initialized to a pointer of type VethPair if the
// veth link was successfully created on Linux host. Newly created pair of veth links
// are assigned random names starting with "veth".
// NewVethPair returns error if the veth pair could not be created.
func NewVethPair() (Vether, error) {
ifcName := makeNetInterfaceName("veth")
peerName := makeNetInterfaceName("veth")
if err := netlink.NetworkCreateVethPair(ifcName, peerName, 0); err != nil {
return nil, err
}
newIfc, err := net.InterfaceByName(ifcName)
if err != nil {
return nil, fmt.Errorf("Could not find the new interface: %s", err)
}
peerIfc, err := net.InterfaceByName(peerName)
if err != nil {
return nil, fmt.Errorf("Could not find the new interface: %s", err)
}
return &VethPair{
Link: Link{
ifc: newIfc,
},
peerIfc: peerIfc,
}, nil
}
// NewVethPairWithOptions creates a pair of veth network links.
//
// It is equivalent of running:
// ip link add name ${first device name} type veth peer name ${second device name}
// NewVethPairWithOptions returns Vether which is initialized to a pointer of type VethPair if the
// veth link was successfully created on the Linux host. It accepts VethOptions which allow you to set
// peer interface name. It returns error if the veth pair could not be created.
func NewVethPairWithOptions(ifcName string, opts VethOptions) (Vether, error) {
peerName := opts.PeerName
txQLen := opts.TxQueueLen
if ok, err := NetInterfaceNameValid(ifcName); !ok {
return nil, err
}
if _, err := net.InterfaceByName(ifcName); err == nil {
return nil, fmt.Errorf("Interface name %s already assigned on the host", ifcName)
}
if peerName != "" {
if ok, err := NetInterfaceNameValid(peerName); !ok {
return nil, err
}
if _, err := net.InterfaceByName(peerName); err == nil {
return nil, fmt.Errorf("Interface name %s already assigned on the host", peerName)
}
} else {
peerName = makeNetInterfaceName("veth")
}
if txQLen < 0 {
return nil, fmt.Errorf("TX queue length must be a positive integer: %d", txQLen)
}
if err := netlink.NetworkCreateVethPair(ifcName, peerName, txQLen); err != nil {
return nil, err
}
newIfc, err := net.InterfaceByName(ifcName)
if err != nil {
return nil, fmt.Errorf("Could not find the new interface: %s", err)
}
peerIfc, err := net.InterfaceByName(peerName)
if err != nil {
return nil, fmt.Errorf("Could not find the new interface: %s", err)
}
return &VethPair{
Link: Link{
ifc: newIfc,
},
peerIfc: peerIfc,
}, nil
}
// NetInterface returns veth link's primary network interface
func (veth *VethPair) NetInterface() *net.Interface {
return veth.ifc
}
// NetInterface returns veth link's peer network interface
func (veth *VethPair) PeerNetInterface() *net.Interface {
return veth.peerIfc
}
// SetPeerLinkUp sets peer link up
func (veth *VethPair) SetPeerLinkUp() error {
return netlink.NetworkLinkUp(veth.peerIfc)
}
// DeletePeerLink deletes peer link. It also deletes the other peer interface in VethPair
func (veth *VethPair) DeletePeerLink() error {
return netlink.NetworkLinkDel(veth.peerIfc.Name)
}
// SetPeerLinkIp configures peer link's IP address
func (veth *VethPair) SetPeerLinkIp(ip net.IP, nw *net.IPNet) error {
return netlink.NetworkLinkAddIp(veth.peerIfc, ip, nw)
}
// SetPeerLinkNsToDocker sends peer link into Docker
func (veth *VethPair) SetPeerLinkNsToDocker(name string, dockerHost string) error {
pid, err := DockerPidByName(name, dockerHost)
if err != nil {
return fmt.Errorf("Failed to find docker %s : %s", name, err)
}
return netlink.NetworkSetNsPid(veth.peerIfc, pid)
}
// SetPeerLinkNsPid sends peer link into container specified by PID
func (veth *VethPair) SetPeerLinkNsPid(nspid int) error {
return netlink.NetworkSetNsPid(veth.peerIfc, nspid)
}
// SetPeerLinkNsFd sends peer link into container specified by path
func (veth *VethPair) SetPeerLinkNsFd(nspath string) error {
fd, err := syscall.Open(nspath, syscall.O_RDONLY, 0)
if err != nil {
return fmt.Errorf("Could not attach to Network namespace: %s", err)
}
return netlink.NetworkSetNsFd(veth.peerIfc, fd)
}
// SetPeerLinkNetInNs configures peer link's IP network in network namespace specified by PID
func (veth *VethPair) SetPeerLinkNetInNs(nspid int, ip net.IP, network *net.IPNet, gw *net.IP) error {
origNs, _ := NetNsHandle(os.Getpid())
defer syscall.Close(int(origNs))
defer system.Setns(origNs, syscall.CLONE_NEWNET)
if err := SetNetNsToPid(nspid); err != nil {
return fmt.Errorf("Setting network namespace failed: %s", err)
}
if err := netlink.NetworkLinkAddIp(veth.peerIfc, ip, network); err != nil {
return fmt.Errorf("Unable to set IP: %s in pid: %d network namespace", ip.String(), nspid)
}
if err := netlink.NetworkLinkUp(veth.peerIfc); err != nil {
return fmt.Errorf("Unable to bring %s interface UP: %d", veth.peerIfc.Name, nspid)
}
if gw != nil {
if err := netlink.AddDefaultGw(gw.String(), veth.peerIfc.Name); err != nil {
return fmt.Errorf("Unable to set Default gateway: %s in pid: %d network namespace", gw.String(), nspid)
}
}
return nil
}