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Merge pull request #553 from aojea/conntrack

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Delete stale UDP conntrack entries when adding new Portmaps to containers
This commit is contained in:
Casey Callendrello
2020-11-25 17:09:43 +01:00
committed by GitHub
parent cccf5395e8 108c2aebd4
commit 509d645ee9
188 changed files with 9512 additions and 4781 deletions
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14
plugins/meta/portmap/main.go
View File

@ -28,12 +28,14 @@ package main
import (
"encoding/json"
"fmt"
"log"
"net"
"github.com/containernetworking/cni/pkg/skel"
"github.com/containernetworking/cni/pkg/types"
"github.com/containernetworking/cni/pkg/types/current"
"github.com/containernetworking/cni/pkg/version"
"golang.org/x/sys/unix"
bv "github.com/containernetworking/plugins/pkg/utils/buildversion"
)
@ -89,12 +91,24 @@ func cmdAdd(args *skel.CmdArgs) error {
if err := forwardPorts(netConf, netConf.ContIPv4); err != nil {
return err
}
// Delete conntrack entries for UDP to avoid conntrack blackholing traffic
// due to stale connections. We do that after the iptables rules are set, so
// the new traffic uses them. Failures are informative only.
if err := deletePortmapStaleConnections(netConf.RuntimeConfig.PortMaps, unix.AF_INET); err != nil {
log.Printf("failed to delete stale UDP conntrack entries for %s: %v", netConf.ContIPv4.IP, err)
}
}
if netConf.ContIPv6.IP != nil {
if err := forwardPorts(netConf, netConf.ContIPv6); err != nil {
return err
}
// Delete conntrack entries for UDP to avoid conntrack blackholing traffic
// due to stale connections. We do that after the iptables rules are set, so
// the new traffic uses them. Failures are informative only.
if err := deletePortmapStaleConnections(netConf.RuntimeConfig.PortMaps, unix.AF_INET6); err != nil {
log.Printf("failed to delete stale UDP conntrack entries for %s: %v", netConf.ContIPv6.IP, err)
}
}
// Pass through the previous result

34
plugins/meta/portmap/portmap.go
View File

@ -19,10 +19,12 @@ import (
"net"
"sort"
"strconv"
"strings"
"github.com/containernetworking/plugins/pkg/utils"
"github.com/containernetworking/plugins/pkg/utils/sysctl"
"github.com/coreos/go-iptables/iptables"
"github.com/vishvananda/netlink"
)
// This creates the chains to be added to iptables. The basic structure is
@ -42,10 +44,12 @@ import (
// The names of the top-level summary chains.
// These should never be changed, or else upgrading will require manual
// intervention.
const TopLevelDNATChainName = "CNI-HOSTPORT-DNAT"
const SetMarkChainName = "CNI-HOSTPORT-SETMARK"
const MarkMasqChainName = "CNI-HOSTPORT-MASQ"
const OldTopLevelSNATChainName = "CNI-HOSTPORT-SNAT"
const (
TopLevelDNATChainName = "CNI-HOSTPORT-DNAT"
SetMarkChainName = "CNI-HOSTPORT-SETMARK"
MarkMasqChainName = "CNI-HOSTPORT-MASQ"
OldTopLevelSNATChainName = "CNI-HOSTPORT-SNAT"
)
// forwardPorts establishes port forwarding to a given container IP.
// containerNet.IP can be either v4 or v6.
@ -113,7 +117,6 @@ func forwardPorts(config *PortMapConf, containerNet net.IPNet) error {
}
func checkPorts(config *PortMapConf, containerNet net.IPNet) error {
dnatChain := genDnatChain(config.Name, config.ContainerID)
fillDnatRules(&dnatChain, config, containerNet)
@ -189,7 +192,7 @@ func fillDnatRules(c *chain, config *PortMapConf, containerNet net.IPNet) {
setMarkChainName = *config.ExternalSetMarkChain
}
//Generate the dnat entry rules. We'll use multiport, but it ony accepts
// Generate the dnat entry rules. We'll use multiport, but it ony accepts
// up to 15 rules, so partition the list if needed.
// Do it in a stable order for testing
protoPorts := groupByProto(entries)
@ -243,7 +246,8 @@ func fillDnatRules(c *chain, config *PortMapConf, containerNet net.IPNet) {
ruleBase := []string{
"-p", entry.Protocol,
"--dport", strconv.Itoa(entry.HostPort)}
"--dport", strconv.Itoa(entry.HostPort),
}
if addRuleBaseDst {
ruleBase = append(ruleBase,
"-d", entry.HostIP)
@ -406,3 +410,19 @@ func maybeGetIptables(isV6 bool) *iptables.IPTables {
return ipt
}
// deletePortmapStaleConnections delete the UDP conntrack entries on the specified IP family
// from the ports mapped to the container
func deletePortmapStaleConnections(portMappings []PortMapEntry, family netlink.InetFamily) error {
for _, pm := range portMappings {
// skip if is not UDP
if strings.ToLower(pm.Protocol) != "udp" {
continue
}
err := utils.DeleteConntrackEntriesForDstPort(uint16(pm.HostPort), utils.PROTOCOL_UDP, family)
if err != nil {
return err
}
}
return nil
}

209
plugins/meta/portmap/portmap_integ_test.go
View File

@ -184,16 +184,16 @@ var _ = Describe("portmap integration tests", func() {
Expect(cmd.Run()).To(Succeed())
// Sanity check: verify that the container is reachable directly
contOK := testEchoServer(contIP.String(), containerPort, "")
contOK := testEchoServer(contIP.String(), "tcp", containerPort, "")
// Verify that a connection to the forwarded port works
dnatOK := testEchoServer(hostIP, hostPort, "")
dnatOK := testEchoServer(hostIP, "tcp", hostPort, "")
// Verify that a connection to localhost works
snatOK := testEchoServer("127.0.0.1", hostPort, "")
snatOK := testEchoServer("127.0.0.1", "tcp", hostPort, "")
// verify that hairpin works
hairpinOK := testEchoServer(hostIP, hostPort, targetNS.Path())
hairpinOK := testEchoServer(hostIP, "tcp", hostPort, targetNS.Path())
// Cleanup
session.Terminate()
@ -219,21 +219,216 @@ var _ = Describe("portmap integration tests", func() {
}
close(done)
}, TIMEOUT*9)
It("forwards a UDP port on ipv4 and keep working after creating a second container with the same HostPort", func(done Done) {
var err error
hostPort := rand.Intn(10000) + 1025
runtimeConfig := libcni.RuntimeConf{
ContainerID: fmt.Sprintf("unit-test-%d", hostPort),
NetNS: targetNS.Path(),
IfName: "eth0",
CapabilityArgs: map[string]interface{}{
"portMappings": []map[string]interface{}{
{
"hostPort": hostPort,
"containerPort": containerPort,
"protocol": "udp",
},
},
},
}
// Make delete idempotent, so we can clean up on failure
netDeleted := false
deleteNetwork := func() error {
if netDeleted {
return nil
}
netDeleted = true
return cniConf.DelNetworkList(context.TODO(), configList, &runtimeConfig)
}
// Create the network
resI, err := cniConf.AddNetworkList(context.TODO(), configList, &runtimeConfig)
Expect(err).NotTo(HaveOccurred())
defer deleteNetwork()
// Undo Docker's forwarding policy
cmd := exec.Command("iptables", "-t", "filter",
"-P", "FORWARD", "ACCEPT")
cmd.Stderr = GinkgoWriter
err = cmd.Run()
Expect(err).NotTo(HaveOccurred())
result, err := current.GetResult(resI)
Expect(err).NotTo(HaveOccurred())
var contIP net.IP
for _, ip := range result.IPs {
intfIndex := *ip.Interface
if result.Interfaces[intfIndex].Sandbox == "" {
continue
}
contIP = ip.Address.IP
}
if contIP == nil {
Fail("could not determine container IP")
}
hostIP := getLocalIP()
fmt.Fprintf(GinkgoWriter, "First container hostIP: %s:%d, contIP: %s:%d\n",
hostIP, hostPort, contIP, containerPort)
// dump iptables-save output for debugging
cmd = exec.Command("iptables-save")
cmd.Stderr = GinkgoWriter
cmd.Stdout = GinkgoWriter
Expect(cmd.Run()).To(Succeed())
// dump ip routes output for debugging
cmd = exec.Command("ip", "route")
cmd.Stderr = GinkgoWriter
cmd.Stdout = GinkgoWriter
Expect(cmd.Run()).To(Succeed())
// dump ip addresses output for debugging
cmd = exec.Command("ip", "addr")
cmd.Stderr = GinkgoWriter
cmd.Stdout = GinkgoWriter
Expect(cmd.Run()).To(Succeed())
// Sanity check: verify that the container is reachable directly
fmt.Fprintln(GinkgoWriter, "Connect to container:", contIP.String(), containerPort)
contOK := testEchoServer(contIP.String(), "udp", containerPort, "")
// Verify that a connection to the forwarded port works
fmt.Fprintln(GinkgoWriter, "Connect to host:", hostIP, hostPort)
dnatOK := testEchoServer(hostIP, "udp", hostPort, "")
// Cleanup
session.Terminate()
err = deleteNetwork()
Expect(err).NotTo(HaveOccurred())
// Check that everything succeeded *after* we clean up the network
if !contOK {
Fail("connection direct to " + contIP.String() + " failed")
}
if !dnatOK {
Fail("Connection to " + hostIP + " was not forwarded")
}
// Create a second container
targetNS2, err := testutils.NewNS()
Expect(err).NotTo(HaveOccurred())
fmt.Fprintln(GinkgoWriter, "namespace:", targetNS2.Path())
// Start an echo server and get the port
containerPort, session2, err := StartEchoServerInNamespace(targetNS2)
Expect(err).NotTo(HaveOccurred())
runtimeConfig2 := libcni.RuntimeConf{
ContainerID: fmt.Sprintf("unit-test2-%d", hostPort),
NetNS: targetNS2.Path(),
IfName: "eth0",
CapabilityArgs: map[string]interface{}{
"portMappings": []map[string]interface{}{
{
"hostPort": hostPort,
"containerPort": containerPort,
"protocol": "udp",
},
},
},
}
// Make delete idempotent, so we can clean up on failure
net2Deleted := false
deleteNetwork2 := func() error {
if net2Deleted {
return nil
}
net2Deleted = true
return cniConf.DelNetworkList(context.TODO(), configList, &runtimeConfig2)
}
// Create the network
resI2, err := cniConf.AddNetworkList(context.TODO(), configList, &runtimeConfig2)
Expect(err).NotTo(HaveOccurred())
defer deleteNetwork2()
result2, err := current.GetResult(resI2)
Expect(err).NotTo(HaveOccurred())
var contIP2 net.IP
for _, ip := range result2.IPs {
intfIndex := *ip.Interface
if result2.Interfaces[intfIndex].Sandbox == "" {
continue
}
contIP2 = ip.Address.IP
}
if contIP2 == nil {
Fail("could not determine container IP")
}
fmt.Fprintf(GinkgoWriter, "Second container: hostIP: %s:%d, contIP: %s:%d\n",
hostIP, hostPort, contIP2, containerPort)
// dump iptables-save output for debugging
cmd = exec.Command("iptables-save")
cmd.Stderr = GinkgoWriter
cmd.Stdout = GinkgoWriter
Expect(cmd.Run()).To(Succeed())
// dump ip routes output for debugging
cmd = exec.Command("ip", "route")
cmd.Stderr = GinkgoWriter
cmd.Stdout = GinkgoWriter
Expect(cmd.Run()).To(Succeed())
// dump ip addresses output for debugging
cmd = exec.Command("ip", "addr")
cmd.Stderr = GinkgoWriter
cmd.Stdout = GinkgoWriter
Expect(cmd.Run()).To(Succeed())
// Sanity check: verify that the container is reachable directly
fmt.Fprintln(GinkgoWriter, "Connect to container:", contIP2.String(), containerPort)
cont2OK := testEchoServer(contIP2.String(), "udp", containerPort, "")
// Verify that a connection to the forwarded port works
fmt.Fprintln(GinkgoWriter, "Connect to host:", hostIP, hostPort)
dnat2OK := testEchoServer(hostIP, "udp", hostPort, "")
// Cleanup
session2.Terminate()
err = deleteNetwork2()
Expect(err).NotTo(HaveOccurred())
// Check that everything succeeded *after* we clean up the network
if !cont2OK {
Fail("connection direct to " + contIP2.String() + " failed")
}
if !dnat2OK {
Fail("Connection to " + hostIP + " was not forwarded")
}
close(done)
}, TIMEOUT*9)
})
})
// testEchoServer returns true if we found an echo server on the port
func testEchoServer(address string, port int, netns string) bool {
func testEchoServer(address, protocol string, port int, netns string) bool {
message := "'Aliquid melius quam pessimum optimum non est.'"
var cmd *exec.Cmd
if netns != "" {
netns = filepath.Base(netns)
cmd = exec.Command("ip", "netns", "exec", netns, echoClientBinaryPath, "--target", fmt.Sprintf("%s:%d", address, port), "--message", message)
cmd = exec.Command("ip", "netns", "exec", netns, echoClientBinaryPath, "--target", fmt.Sprintf("%s:%d", address, port), "--message", message, "--protocol", protocol)
} else {
cmd = exec.Command(echoClientBinaryPath, "--target", fmt.Sprintf("%s:%d", address, port), "--message", message)
cmd = exec.Command(echoClientBinaryPath, "--target", fmt.Sprintf("%s:%d", address, port), "--message", message, "--protocol", protocol)
}
cmd.Stdin = bytes.NewBufferString(message)
cmd.Stderr = GinkgoWriter