func cmdAdd(args *skel.CmdArgs) error {
n, err := loadNetConf(args.StdinData)
if err != nil {
return err
}
br, err := setupBridge(n)
if err != nil {
return err
}
if err = setupVeth(args.Netns, br, args.IfName, n.MTU); err != nil {
return err
}
// run the IPAM plugin and get back the config to apply
result, err := ipam.ExecAdd(n.IPAM.Type, args.StdinData)
if err != nil {
return err
}
if result.IP4 == nil {
return errors.New("IPAM plugin returned missing IPv4 config")
}
if result.IP4.Gateway == nil && n.IsGW {
result.IP4.Gateway = calcGatewayIP(&result.IP4.IP)
}
err = ns.WithNetNSPath(args.Netns, false, func(hostNS *os.File) error {
return ipam.ConfigureIface(args.IfName, result)
})
if err != nil {
return err
}
if n.IsGW {
gwn := &net.IPNet{
IP: result.IP4.Gateway,
Mask: result.IP4.IP.Mask,
}
if err = ensureBridgeAddr(br, gwn); err != nil {
return err
}
if err := ip.EnableIP4Forward(); err != nil {
return fmt.Errorf("failed to enable forwarding: %v", err)
}
}
if n.IPMasq {
chain := "CNI-" + n.Name
if err = ip.SetupIPMasq(ip.Network(&result.IP4.IP), chain); err != nil {
return err
}
}
return result.Print()
}
func cmdAdd(args *skel.CmdArgs) error {
n, err := loadConf(args.StdinData)
if err != nil {
return err
}
netns, err := os.Open(args.Netns)
if err != nil {
return fmt.Errorf("failed to open netns %q: %v", netns, err)
}
defer netns.Close()
if err = createIpvlan(n, args.IfName, netns); err != nil {
return err
}
// run the IPAM plugin and get back the config to apply
result, err := ipam.ExecAdd(n.IPAM.Type, args.StdinData)
if err != nil {
return err
}
if result.IP4 == nil {
return errors.New("IPAM plugin returned missing IPv4 config")
}
err = ns.WithNetNS(netns, false, func(_ *os.File) error {
return ipam.ConfigureIface(args.IfName, result)
})
if err != nil {
return err
}
return result.Print()
}
func setupContainerVeth(netns, ifName string, mtu int, pr *types.Result) (string, error) {
// The IPAM result will be something like IP=192.168.3.5/24, GW=192.168.3.1.
// What we want is really a point-to-point link but veth does not support IFF_POINTOPONT.
// Next best thing would be to let it ARP but set interface to 192.168.3.5/32 and
// add a route like "192.168.3.0/24 via 192.168.3.1 dev $ifName".
// Unfortunately that won't work as the GW will be outside the interface's subnet.
// Our solution is to configure the interface with 192.168.3.5/24, then delete the
// "192.168.3.0/24 dev $ifName" route that was automatically added. Then we add
// "192.168.3.1/32 dev $ifName" and "192.168.3.0/24 via 192.168.3.1 dev $ifName".
// In other words we force all traffic to ARP via the gateway except for GW itself.
var hostVethName string
err := ns.WithNetNSPath(netns, false, func(hostNS *os.File) error {
hostVeth, _, err := ip.SetupVeth(ifName, mtu, hostNS)
if err != nil {
return err
}
if err = ipam.ConfigureIface(ifName, pr); err != nil {
return err
}
contVeth, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to look up %q: %v", ifName, err)
}
// Delete the route that was automatically added
route := netlink.Route{
LinkIndex: contVeth.Attrs().Index,
Dst: &net.IPNet{
IP: pr.IP4.IP.IP.Mask(pr.IP4.IP.Mask),
Mask: pr.IP4.IP.Mask,
},
Scope: netlink.SCOPE_NOWHERE,
}
if err := netlink.RouteDel(&route); err != nil {
return fmt.Errorf("failed to delete route %v: %v", route, err)
}
for _, r := range []netlink.Route{
netlink.Route{
LinkIndex: contVeth.Attrs().Index,
Dst: &net.IPNet{
IP: pr.IP4.Gateway,
Mask: net.CIDRMask(32, 32),
},
Scope: netlink.SCOPE_LINK,
Src: pr.IP4.IP.IP,
},
netlink.Route{
LinkIndex: contVeth.Attrs().Index,
Dst: &net.IPNet{
IP: pr.IP4.IP.IP.Mask(pr.IP4.IP.Mask),
Mask: pr.IP4.IP.Mask,
},
Scope: netlink.SCOPE_UNIVERSE,
Gw: pr.IP4.Gateway,
Src: pr.IP4.IP.IP,
},
} {
if err := netlink.RouteAdd(&r); err != nil {
return fmt.Errorf("failed to add route %v: %v", r, err)
}
}
hostVethName = hostVeth.Attrs().Name
return nil
})
return hostVethName, err
}