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nic.go
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nic.go
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// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.
package wireguard
import (
"errors"
"fmt"
"os"
current "github.com/containernetworking/cni/pkg/types/100"
cniipam "github.com/containernetworking/plugins/pkg/ipam"
"github.com/containernetworking/plugins/pkg/ns"
"github.com/vishvananda/netlink"
"go.uber.org/multierr"
"github.com/Azure/kube-egress-gateway/pkg/cni/ipam"
"github.com/Azure/kube-egress-gateway/pkg/netlinkwrapper"
"github.com/Azure/kube-egress-gateway/pkg/netnswrapper"
)
type runner struct {
netlink netlinkwrapper.Interface
netns netnswrapper.Interface
}
var nicRunner runner
func init() {
nicRunner = runner{
netlink: netlinkwrapper.NewNetLink(),
netns: netnswrapper.NewNetNS(),
}
}
func WithWireGuardNic(containerID string, podNSPath string, ifName string, ipWrapper ipam.IPProvider, exludedRoute []string, result *current.Result, configFunc func(podNs ns.NetNS, allowedIPNet string) error) (err error) {
podNetNS, err := nicRunner.netns.GetNSByPath(podNSPath)
if err != nil {
return err
}
defer podNetNS.Close()
var wgLink netlink.Link
// get existing interface in target ns
err = podNetNS.Do(func(nn ns.NetNS) error {
wgLink, err = nicRunner.netlink.LinkByName(ifName)
if err != nil {
if _, ok := err.(netlink.LinkNotFoundError); !ok {
return fmt.Errorf("failed to retrieve new WireGuard link: %w", err)
}
}
return nil
})
if err != nil {
return err
}
// if not found create one and move to pod ns
if wgLink == nil {
wgNameInMain := "wg" + containerID[0:8] // avoid name conflict in main ns
linkAttributes := netlink.NewLinkAttrs()
linkAttributes.Name = wgNameInMain
wireguardInterface := &netlink.Wireguard{
LinkAttrs: linkAttributes,
}
defer func() {
if err != nil {
if wgLink, recoverErr := nicRunner.netlink.LinkByName(wgNameInMain); recoverErr != nil {
if _, ok := recoverErr.(netlink.LinkNotFoundError); !ok {
err = multierr.Append(err, recoverErr)
}
} else if recoverErr := nicRunner.netlink.LinkDel(wgLink); recoverErr != nil {
err = multierr.Append(err, recoverErr)
}
recoverErr := podNetNS.Do(func(nn ns.NetNS) error {
var err error
if wgLink, recoverErr := nicRunner.netlink.LinkByName(wgNameInMain); recoverErr != nil {
if _, ok := recoverErr.(netlink.LinkNotFoundError); !ok {
err = multierr.Append(err, recoverErr)
}
} else if recoverErr := nicRunner.netlink.LinkDel(wgLink); recoverErr != nil {
err = multierr.Append(err, recoverErr)
}
if wgLink, recoverErr := nicRunner.netlink.LinkByName(ifName); recoverErr != nil {
if _, ok := recoverErr.(netlink.LinkNotFoundError); !ok {
err = multierr.Append(err, recoverErr)
}
} else if recoverErr := nicRunner.netlink.LinkDel(wgLink); recoverErr != nil {
err = multierr.Append(err, recoverErr)
}
return err
})
if recoverErr != nil {
err = multierr.Append(err, recoverErr)
}
}
}()
err = nicRunner.netlink.LinkAdd(wireguardInterface)
if err != nil {
return fmt.Errorf("failed to add WireGuard link: %w", err)
}
wgLink, err = nicRunner.netlink.LinkByName(wgNameInMain)
if err != nil {
return err
}
err = nicRunner.netlink.LinkSetNsFd(wgLink, int(podNetNS.Fd()))
if err != nil {
return fmt.Errorf("failed to move wireguard link to pod namespace: %w", err)
}
err = podNetNS.Do(func(nn ns.NetNS) error {
wgLink, err = nicRunner.netlink.LinkByName(wgNameInMain)
if err != nil {
return fmt.Errorf("failed to find %q: %v", wgNameInMain, err)
}
// Devices can be renamed only when down
if err = nicRunner.netlink.LinkSetDown(wgLink); err != nil {
return fmt.Errorf("failed to set %q down: %v", wgLink.Attrs().Name, err)
}
// Save host device name into the container device's alias property
if err := nicRunner.netlink.LinkSetAlias(wgLink, wgLink.Attrs().Name); err != nil {
return fmt.Errorf("failed to set alias to %q: %v", wgLink.Attrs().Name, err)
}
// Rename container device to respect args.IfName
if err := nicRunner.netlink.LinkSetName(wgLink, ifName); err != nil {
return fmt.Errorf("failed to rename device %q to %q: %v", wgLink.Attrs().Name, ifName, err)
}
// Bring container device up
if err = nicRunner.netlink.LinkSetUp(wgLink); err != nil {
return fmt.Errorf("failed to set %q up: %v", ifName, err)
}
return nil
})
if err != nil {
return err
}
}
return ipWrapper.WithIP(func(ipamResult *current.Result) error {
if ipamResult == nil || len(ipamResult.IPs) <= 0 {
return errors.New("ipam result is empty")
}
allowedIPNet := ""
err = podNetNS.Do(func(nn ns.NetNS) error {
// Retrieve link again to get up-to-date name and attributes
wgLink, err = nicRunner.netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to find %q: %v", ifName, err)
}
ipamResult.Interfaces = []*current.Interface{
{
Mac: wgLink.Attrs().HardwareAddr.String(),
Name: wgLink.Attrs().Name,
Sandbox: podNSPath,
},
}
result.Interfaces = append(result.Interfaces, ipamResult.Interfaces[0])
for _, item := range ipamResult.IPs {
if item.Address.IP.To4() == nil {
// add ipv6 ip to result
item.Interface = current.Int(0)
result.IPs = append(result.IPs, ¤t.IPConfig{
Interface: current.Int(len(result.Interfaces) - 1),
Address: item.Address,
})
} else {
// pod ipv4 ip should be added in wireguard configuration as allowed ip
allowedIPNet = fmt.Sprintf("%s/32", item.Address.IP.String())
}
}
if os.Getenv("IS_UNIT_TEST_ENV") != "true" {
return cniipam.ConfigureIface(ifName, ipamResult)
} else {
return nil
}
})
if err != nil {
return err
}
if allowedIPNet == "" {
return fmt.Errorf("failed to find pod ipv4 ip")
}
if configFunc != nil {
return configFunc(podNetNS, allowedIPNet)
}
return nil
})
}