104 lines
2.2 KiB
Go
104 lines
2.2 KiB
Go
package netlink
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import (
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"antoine-roux.tk/projects/go/firecracker-netns/internal/netns"
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"crypto/rand"
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"fmt"
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"github.com/vishvananda/netlink"
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)
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// inspired by https://github.com/containernetworking/plugins/blob/main/pkg/ip/link_linux.go#L57
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type Peer struct {
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link netlink.Link
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netNs netns.NsHandle
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}
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type PairLink struct {
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host Peer
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guest Peer
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}
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func NewVethPair(ns netns.NsHandle) (pair *PairLink, error error) {
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origins, err := netns.Get()
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if err != nil {
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return nil, err
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}
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err = netns.Set(ns)
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if err != nil {
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return nil, err
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}
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name, err := randomVethName()
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if err != nil {
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return nil, err
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}
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peerName, err := randomVethName()
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if err != nil {
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return nil, err
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}
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attrs := netlink.NewLinkAttrs()
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attrs.Name = name
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veth := &netlink.Veth{
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LinkAttrs: attrs,
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PeerName: peerName,
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PeerNamespace: netlink.NsFd(origins.Fd),
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}
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if err := netlink.LinkAdd(veth); err != nil {
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return nil, err
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}
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// Re-fetch the container link to get its creation-time parameters, e.g. index and mac
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fmt.Println(name)
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veth2, err := netlink.LinkByName(name)
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if err != nil {
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netlink.LinkDel(veth)
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return nil, err
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}
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err = netns.Set(origins)
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if err != nil {
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return nil, err
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}
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fmt.Println(peerName)
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veth1, err := netlink.LinkByName(peerName)
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if err != nil {
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netlink.LinkDel(veth)
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return nil, err
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}
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return &PairLink{host: Peer{veth1, origins}, guest: Peer{veth2, ns}}, nil
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}
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// DeleteLink removes an interface link.
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func (p *PairLink) DeleteLink() error {
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err := netns.Set(p.host.netNs)
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if err != nil {
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return fmt.Errorf("set original Ns for deleting veth %q: %v", p.host.link.Attrs().Name, err)
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}
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if err := netlink.LinkDel(p.host.link); err != nil {
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return fmt.Errorf("failed to delete %q: %v", p.host.link.Attrs().Name, err)
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}
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return nil
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}
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// randomVethName returns string "veth" with random prefix (hashed from entropy)
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func randomVethName() (string, error) {
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entropy := make([]byte, 4)
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_, err := rand.Read(entropy)
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if err != nil {
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return "", fmt.Errorf("failed to generate random veth name: %v", err)
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}
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// NetworkManager (recent versions) will ignore veth devices that start with "veth"
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return fmt.Sprintf("veth%x", entropy), nil
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}
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