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cnilink.go
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cnilink.go
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package main
import (
"fmt"
"net"
"github.com/containernetworking/cni/pkg/ns"
"github.com/vishvananda/netlink"
)
//
// TODO
// Warning!
// Functions in this file are ported over from containernetworking/cni/ip/link.go
// for a reason that we can't use ip.SetupVeth with random hostVeth name.
//
// SetupVeth sets up a pair of virtual ethernet devices.
// Call SetupVeth from inside the container netns. It will create both veth
// devices and move the host-side veth into the provided hostNS namespace.
// On success, SetupVeth returns (hostVeth, containerVeth, nil)
func SetupVeth(contVethName, hostVethName string, mtu int, hostNS ns.NetNS) (net.Interface, net.Interface, error) {
contVeth, err := makeVethPair(contVethName, hostVethName, mtu)
if err != nil {
return net.Interface{}, net.Interface{}, err
}
if err = netlink.LinkSetUp(contVeth); err != nil {
return net.Interface{}, net.Interface{}, fmt.Errorf("failed to set %q up: %v", contVethName, err)
}
hostVeth, err := netlink.LinkByName(hostVethName)
if err != nil {
return net.Interface{}, net.Interface{}, fmt.Errorf("failed to lookup %q: %v", hostVethName, err)
}
if err = netlink.LinkSetNsFd(hostVeth, int(hostNS.Fd())); err != nil {
return net.Interface{}, net.Interface{}, fmt.Errorf("failed to move veth to host netns: %v", err)
}
err = hostNS.Do(func(_ ns.NetNS) error {
hostVeth, err = netlink.LinkByName(hostVethName)
if err != nil {
return fmt.Errorf("failed to lookup %q in %q: %v", hostVethName, hostNS.Path(), err)
}
if err = netlink.LinkSetUp(hostVeth); err != nil {
return fmt.Errorf("failed to set %q up: %v", hostVethName, err)
}
return nil
})
if err != nil {
return net.Interface{}, net.Interface{}, err
}
return ifaceFromNetlinkLink(hostVeth), ifaceFromNetlinkLink(contVeth), nil
}
func makeVethPair(name, peer string, mtu int) (netlink.Link, error) {
veth := &netlink.Veth{
LinkAttrs: netlink.LinkAttrs{
Name: name,
Flags: net.FlagUp,
MTU: mtu,
},
PeerName: peer,
}
if err := netlink.LinkAdd(veth); err != nil {
return nil, err
}
return veth, nil
}
func ifaceFromNetlinkLink(l netlink.Link) net.Interface {
a := l.Attrs()
return net.Interface{
Index: a.Index,
MTU: a.MTU,
Name: a.Name,
HardwareAddr: a.HardwareAddr,
Flags: a.Flags,
}
}