141 lines
3.8 KiB
Go
141 lines
3.8 KiB
Go
package ns
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import (
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"fmt"
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"os"
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"os/exec"
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"strings"
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"sync"
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"syscall"
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"time"
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"github.com/sirupsen/logrus"
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"github.com/vishvananda/netlink"
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"github.com/vishvananda/netns"
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)
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var (
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initNs netns.NsHandle
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initNl *netlink.Handle
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initOnce sync.Once
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// NetlinkSocketsTimeout represents the default timeout duration for the sockets
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NetlinkSocketsTimeout = 3 * time.Second
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)
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// Init initializes a new network namespace
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func Init() {
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var err error
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initNs, err = netns.Get()
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if err != nil {
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logrus.Errorf("could not get initial namespace: %v", err)
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}
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initNl, err = netlink.NewHandle(getSupportedNlFamilies()...)
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if err != nil {
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logrus.Errorf("could not create netlink handle on initial namespace: %v", err)
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}
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err = initNl.SetSocketTimeout(NetlinkSocketsTimeout)
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if err != nil {
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logrus.Warnf("Failed to set the timeout on the default netlink handle sockets: %v", err)
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}
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}
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// SetNamespace sets the initial namespace handler
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func SetNamespace() error {
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initOnce.Do(Init)
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if err := netns.Set(initNs); err != nil {
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linkInfo, linkErr := getLink()
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if linkErr != nil {
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linkInfo = linkErr.Error()
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}
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return fmt.Errorf("failed to set to initial namespace, %v, initns fd %d: %v", linkInfo, initNs, err)
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}
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return nil
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}
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// ParseHandlerInt transforms the namespace handler into an integer
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func ParseHandlerInt() int {
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return int(getHandler())
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}
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// GetHandler returns the namespace handler
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func getHandler() netns.NsHandle {
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initOnce.Do(Init)
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return initNs
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}
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func getLink() (string, error) {
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return os.Readlink(fmt.Sprintf("/proc/%d/task/%d/ns/net", os.Getpid(), syscall.Gettid()))
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}
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// NlHandle returns the netlink handler
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func NlHandle() *netlink.Handle {
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initOnce.Do(Init)
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return initNl
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}
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func getSupportedNlFamilies() []int {
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fams := []int{syscall.NETLINK_ROUTE}
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// NETLINK_XFRM test
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if err := loadXfrmModules(); err != nil {
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if checkXfrmSocket() != nil {
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logrus.Warnf("Could not load necessary modules for IPSEC rules: %v", err)
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} else {
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fams = append(fams, syscall.NETLINK_XFRM)
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}
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} else {
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fams = append(fams, syscall.NETLINK_XFRM)
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}
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// NETLINK_NETFILTER test
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if err := loadNfConntrackModules(); err != nil {
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if checkNfSocket() != nil {
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logrus.Warnf("Could not load necessary modules for Conntrack: %v", err)
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} else {
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fams = append(fams, syscall.NETLINK_NETFILTER)
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}
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} else {
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fams = append(fams, syscall.NETLINK_NETFILTER)
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}
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return fams
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}
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func loadXfrmModules() error {
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if out, err := exec.Command("modprobe", "-va", "xfrm_user").CombinedOutput(); err != nil {
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return fmt.Errorf("Running modprobe xfrm_user failed with message: `%s`, error: %v", strings.TrimSpace(string(out)), err)
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}
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if out, err := exec.Command("modprobe", "-va", "xfrm_algo").CombinedOutput(); err != nil {
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return fmt.Errorf("Running modprobe xfrm_algo failed with message: `%s`, error: %v", strings.TrimSpace(string(out)), err)
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}
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return nil
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}
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// API check on required xfrm modules (xfrm_user, xfrm_algo)
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func checkXfrmSocket() error {
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fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, syscall.NETLINK_XFRM)
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if err != nil {
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return err
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}
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syscall.Close(fd)
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return nil
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}
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func loadNfConntrackModules() error {
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if out, err := exec.Command("modprobe", "-va", "nf_conntrack").CombinedOutput(); err != nil {
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return fmt.Errorf("Running modprobe nf_conntrack failed with message: `%s`, error: %v", strings.TrimSpace(string(out)), err)
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}
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if out, err := exec.Command("modprobe", "-va", "nf_conntrack_netlink").CombinedOutput(); err != nil {
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return fmt.Errorf("Running modprobe nf_conntrack_netlink failed with message: `%s`, error: %v", strings.TrimSpace(string(out)), err)
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}
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return nil
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}
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// API check on required nf_conntrack* modules (nf_conntrack, nf_conntrack_netlink)
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func checkNfSocket() error {
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fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, syscall.NETLINK_NETFILTER)
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if err != nil {
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return err
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}
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syscall.Close(fd)
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return nil
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}
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