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bridge: Add mac field to specify container iface mac

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Controlling the mac address of the interface (veth peer) in the
container is useful for functionalities that depend on the mac address.
Examples range from dynamic IP allocations based on an identifier (the
mac) and up to firewall rules (e.g. no-mac-spoofing).

Enforcing a mac address at an early stage and not through a chained
plugin assures the configuration does not have wrong intermediate
configuration. This is especially critical when a dynamic IP may be
provided already in this period.
But it also has implications for future abilities that may land on the
bridge plugin, e.g. supporting no-mac-spoofing.

The field name used (`mac`) fits with other plugins which control the
mac address of the container interface.

The mac address may be specified through the following methods:
- CNI_ARGS
- Args
- RuntimeConfig [1]

The list is ordered by priority, from lowest to higher. The higher
priority method overrides any previous settings.
(e.g. if the mac is specified in RuntimeConfig, it will override any
specifications of the mac mentioned in CNI_ARGS or Args)

[1] To use RuntimeConfig, the network configuration should include the
`capabilities` field with `mac` specified (`"capabilities": {"mac": true}`).

Signed-off-by: Edward Haas <edwardh@redhat.com>
This commit is contained in:
Edward Haas
2021-06-07 15:42:12 +03:00
parent 8de0287741
commit a3cde17fc0
5 changed files with 199 additions and 24 deletions
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21
pkg/ip/link_linux.go
View File

@ -33,7 +33,7 @@ var (
ErrLinkNotFound = errors.New("link not found")
)
func makeVethPair(name, peer string, mtu int) (netlink.Link, error) {
func makeVethPair(name, peer string, mtu int, mac string) (netlink.Link, error) {
veth := &netlink.Veth{
LinkAttrs: netlink.LinkAttrs{
Name: name,
@ -42,6 +42,13 @@ func makeVethPair(name, peer string, mtu int) (netlink.Link, error) {
},
PeerName: peer,
}
if mac != "" {
m, err := net.ParseMAC(mac)
if err != nil {
return nil, err
}
veth.LinkAttrs.HardwareAddr = m
}
if err := netlink.LinkAdd(veth); err != nil {
return nil, err
}
@ -62,7 +69,7 @@ func peerExists(name string) bool {
return true
}
func makeVeth(name, vethPeerName string, mtu int) (peerName string, veth netlink.Link, err error) {
func makeVeth(name, vethPeerName string, mtu int, mac string) (peerName string, veth netlink.Link, err error) {
for i := 0; i < 10; i++ {
if vethPeerName != "" {
peerName = vethPeerName
@ -73,7 +80,7 @@ func makeVeth(name, vethPeerName string, mtu int) (peerName string, veth netlink
}
}
veth, err = makeVethPair(name, peerName, mtu)
veth, err = makeVethPair(name, peerName, mtu, mac)
switch {
case err == nil:
return
@ -132,8 +139,8 @@ func ifaceFromNetlinkLink(l netlink.Link) net.Interface {
// devices and move the host-side veth into the provided hostNS namespace.
// hostVethName: If hostVethName is not specified, the host-side veth name will use a random string.
// On success, SetupVethWithName returns (hostVeth, containerVeth, nil)
func SetupVethWithName(contVethName, hostVethName string, mtu int, hostNS ns.NetNS) (net.Interface, net.Interface, error) {
hostVethName, contVeth, err := makeVeth(contVethName, hostVethName, mtu)
func SetupVethWithName(contVethName, hostVethName string, mtu int, contVethMac string, hostNS ns.NetNS) (net.Interface, net.Interface, error) {
hostVethName, contVeth, err := makeVeth(contVethName, hostVethName, mtu, contVethMac)
if err != nil {
return net.Interface{}, net.Interface{}, err
}
@ -175,8 +182,8 @@ func SetupVethWithName(contVethName, hostVethName string, mtu int, hostNS ns.Net
// 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 string, mtu int, hostNS ns.NetNS) (net.Interface, net.Interface, error) {
return SetupVethWithName(contVethName, "", mtu, hostNS)
func SetupVeth(contVethName string, mtu int, contVethMac string, hostNS ns.NetNS) (net.Interface, net.Interface, error) {
return SetupVethWithName(contVethName, "", mtu, contVethMac, hostNS)
}
// DelLinkByName removes an interface link.