Add nftables implementation of ipmasq
Signed-off-by: Dan Winship <danwinship@redhat.com>
This commit is contained in:
Dan Winship
committed by
Casey Callendrello
Casey Callendrello
parent
729dd23c40
commit
61d078645a
@ -15,111 +15,78 @@
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package ip
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import (
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"errors"
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"fmt"
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"net"
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"strings"
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"github.com/coreos/go-iptables/iptables"
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"github.com/containernetworking/cni/pkg/types"
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"github.com/containernetworking/plugins/pkg/utils"
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)
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// SetupIPMasq installs iptables rules to masquerade traffic
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// coming from ip of ipn and going outside of ipn
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func SetupIPMasq(ipn *net.IPNet, chain string, comment string) error {
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isV6 := ipn.IP.To4() == nil
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var ipt *iptables.IPTables
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var err error
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var multicastNet string
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if isV6 {
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ipt, err = iptables.NewWithProtocol(iptables.ProtocolIPv6)
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multicastNet = "ff00::/8"
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} else {
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ipt, err = iptables.NewWithProtocol(iptables.ProtocolIPv4)
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multicastNet = "224.0.0.0/4"
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}
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if err != nil {
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return fmt.Errorf("failed to locate iptables: %v", err)
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}
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// Create chain if doesn't exist
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exists := false
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chains, err := ipt.ListChains("nat")
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if err != nil {
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return fmt.Errorf("failed to list chains: %v", err)
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}
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for _, ch := range chains {
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if ch == chain {
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exists = true
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break
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}
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}
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if !exists {
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if err = ipt.NewChain("nat", chain); err != nil {
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return err
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// SetupIPMasqForNetwork installs rules to masquerade traffic coming from ip of ipn and
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// going outside of ipn, using a chain name based on network, ifname, and containerID. The
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// backend can be either "iptables" or "nftables"; if it is nil, then a suitable default
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// implementation will be used.
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func SetupIPMasqForNetwork(backend *string, ipn *net.IPNet, network, ifname, containerID string) error {
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if backend == nil {
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// Prefer iptables, unless only nftables is available
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defaultBackend := "iptables"
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if !utils.SupportsIPTables() && utils.SupportsNFTables() {
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defaultBackend = "nftables"
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}
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backend = &defaultBackend
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}
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// Packets to this network should not be touched
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if err := ipt.AppendUnique("nat", chain, "-d", ipn.String(), "-j", "ACCEPT", "-m", "comment", "--comment", comment); err != nil {
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return err
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switch *backend {
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case "iptables":
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return setupIPMasqIPTables(ipn, network, ifname, containerID)
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case "nftables":
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return setupIPMasqNFTables(ipn, network, ifname, containerID)
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default:
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return fmt.Errorf("unknown ipmasq backend %q", *backend)
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}
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// Don't masquerade multicast - pods should be able to talk to other pods
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// on the local network via multicast.
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if err := ipt.AppendUnique("nat", chain, "!", "-d", multicastNet, "-j", "MASQUERADE", "-m", "comment", "--comment", comment); err != nil {
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return err
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}
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// Packets from the specific IP of this network will hit the chain
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return ipt.AppendUnique("nat", "POSTROUTING", "-s", ipn.IP.String(), "-j", chain, "-m", "comment", "--comment", comment)
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}
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// TeardownIPMasq undoes the effects of SetupIPMasq
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func TeardownIPMasq(ipn *net.IPNet, chain string, comment string) error {
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isV6 := ipn.IP.To4() == nil
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// TeardownIPMasqForNetwork undoes the effects of SetupIPMasqForNetwork
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func TeardownIPMasqForNetwork(ipn *net.IPNet, network, ifname, containerID string) error {
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var errs []string
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var ipt *iptables.IPTables
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var err error
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// Do both the iptables and the nftables cleanup, since the pod may have been
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// created with a different version of this plugin or a different configuration.
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if isV6 {
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ipt, err = iptables.NewWithProtocol(iptables.ProtocolIPv6)
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} else {
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ipt, err = iptables.NewWithProtocol(iptables.ProtocolIPv4)
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}
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if err != nil {
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return fmt.Errorf("failed to locate iptables: %v", err)
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err := teardownIPMasqIPTables(ipn, network, ifname, containerID)
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if err != nil && utils.SupportsIPTables() {
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errs = append(errs, err.Error())
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}
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err = ipt.Delete("nat", "POSTROUTING", "-s", ipn.IP.String(), "-j", chain, "-m", "comment", "--comment", comment)
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if err != nil && !isNotExist(err) {
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return err
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err = teardownIPMasqNFTables(ipn, network, ifname, containerID)
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if err != nil && utils.SupportsNFTables() {
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errs = append(errs, err.Error())
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}
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// for downward compatibility
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err = ipt.Delete("nat", "POSTROUTING", "-s", ipn.String(), "-j", chain, "-m", "comment", "--comment", comment)
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if err != nil && !isNotExist(err) {
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return err
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if errs == nil {
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return nil
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}
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err = ipt.ClearChain("nat", chain)
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if err != nil && !isNotExist(err) {
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return err
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}
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err = ipt.DeleteChain("nat", chain)
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if err != nil && !isNotExist(err) {
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return err
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}
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return nil
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return errors.New(strings.Join(errs, "\n"))
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}
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// isNotExist returnst true if the error is from iptables indicating
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// that the target does not exist.
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func isNotExist(err error) bool {
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e, ok := err.(*iptables.Error)
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if !ok {
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return false
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// GCIPMasqForNetwork garbage collects stale IPMasq entries for network
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func GCIPMasqForNetwork(network string, attachments []types.GCAttachment) error {
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var errs []string
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err := gcIPMasqIPTables(network, attachments)
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if err != nil && utils.SupportsIPTables() {
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errs = append(errs, err.Error())
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}
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return e.IsNotExist()
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err = gcIPMasqNFTables(network, attachments)
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if err != nil && utils.SupportsNFTables() {
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errs = append(errs, err.Error())
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}
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if errs == nil {
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return nil
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}
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return errors.New(strings.Join(errs, "\n"))
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}
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