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00bf437d84
A recent change to the vishvananda/netlink package exposes NLM_F_DUMP_INTR in some netlink responses as an EINTR (with no data). Retry the requests when that happens, up to five times, before returning the error. The limit of five is arbitrary, on most systems a single retry will be rare but, there's no guarantee that a retry will succeed. So, on a very busy or misbehaving system the error may still be returned. In most cases, this will lead to failure of the operation being attempted (which may lead to daemon startup failure, network initialisation failure etc). Signed-off-by: Rob Murray <rob.murray@docker.com>
110 lines
2.9 KiB
Go
110 lines
2.9 KiB
Go
package ns
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import (
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"context"
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"fmt"
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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/containerd/log"
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"github.com/docker/docker/internal/nlwrap"
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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 nlwrap.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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log.G(context.TODO()).Errorf("could not get initial namespace: %v", err)
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}
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initNl, err = nlwrap.NewHandle(getSupportedNlFamilies()...)
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if err != nil {
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log.G(context.TODO()).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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log.G(context.TODO()).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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// 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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// NlHandle returns the netlink handler
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func NlHandle() nlwrap.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 := checkXfrmSocket(); err != nil {
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log.G(context.TODO()).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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// NETLINK_NETFILTER test
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if err := loadNfConntrackModules(); err != nil {
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if checkNfSocket() != nil {
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log.G(context.TODO()).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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// 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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