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authorOpenShift Merge Robot <openshift-merge-robot@users.noreply.github.com>2022-02-10 12:24:03 -0500
committerGitHub <noreply@github.com>2022-02-10 12:24:03 -0500
commit0144413a5a0c07f8df7e089ce976ec3afa7fb5e9 (patch)
treec6e17077e2c3d1cf41933fb0c06a4d598aeb7861
parent9cf1b1bd2fde4d82864ab8ff96298c4f48e51613 (diff)
parent87cca4e5e302050f0ed6b37f3922c769f278efc0 (diff)
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Merge pull request #13191 from mheon/resolvconf_fixes
Modify /etc/resolv.conf when connecting/disconnecting
-rw-r--r--libpod/container_internal_linux.go134
-rw-r--r--libpod/networking_linux.go48
-rw-r--r--test/e2e/network_connect_disconnect_test.go31
3 files changed, 190 insertions, 23 deletions
diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 95f1634a8..afa351c17 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -2045,19 +2045,8 @@ func (c *Container) generateResolvConf() (string, error) {
}
}
- ipv6 := false
- // If network status is set check for ipv6 and dns namesevers
netStatus := c.getNetworkStatus()
for _, status := range netStatus {
- for _, netInt := range status.Interfaces {
- for _, netAddress := range netInt.Subnets {
- // Note: only using To16() does not work since it also returns a valid ip for ipv4
- if netAddress.IPNet.IP.To4() == nil && netAddress.IPNet.IP.To16() != nil {
- ipv6 = true
- }
- }
- }
-
if status.DNSServerIPs != nil {
for _, nsIP := range status.DNSServerIPs {
networkNameServers = append(networkNameServers, nsIP.String())
@@ -2070,16 +2059,9 @@ func (c *Container) generateResolvConf() (string, error) {
}
}
- if c.config.NetMode.IsSlirp4netns() {
- ctrNetworkSlipOpts := []string{}
- if c.config.NetworkOptions != nil {
- ctrNetworkSlipOpts = append(ctrNetworkSlipOpts, c.config.NetworkOptions["slirp4netns"]...)
- }
- slirpOpts, err := parseSlirp4netnsNetworkOptions(c.runtime, ctrNetworkSlipOpts)
- if err != nil {
- return "", err
- }
- ipv6 = slirpOpts.enableIPv6
+ ipv6, err := c.checkForIPv6(netStatus)
+ if err != nil {
+ return "", err
}
// Ensure that the container's /etc/resolv.conf is compatible with its
@@ -2160,6 +2142,116 @@ func (c *Container) generateResolvConf() (string, error) {
return destPath, nil
}
+// Check if a container uses IPv6.
+func (c *Container) checkForIPv6(netStatus map[string]types.StatusBlock) (bool, error) {
+ for _, status := range netStatus {
+ for _, netInt := range status.Interfaces {
+ for _, netAddress := range netInt.Subnets {
+ // Note: only using To16() does not work since it also returns a valid ip for ipv4
+ if netAddress.IPNet.IP.To4() == nil && netAddress.IPNet.IP.To16() != nil {
+ return true, nil
+ }
+ }
+ }
+ }
+
+ if c.config.NetMode.IsSlirp4netns() {
+ ctrNetworkSlipOpts := []string{}
+ if c.config.NetworkOptions != nil {
+ ctrNetworkSlipOpts = append(ctrNetworkSlipOpts, c.config.NetworkOptions["slirp4netns"]...)
+ }
+ slirpOpts, err := parseSlirp4netnsNetworkOptions(c.runtime, ctrNetworkSlipOpts)
+ if err != nil {
+ return false, err
+ }
+ return slirpOpts.enableIPv6, nil
+ }
+
+ return false, nil
+}
+
+// Add a new nameserver to the container's resolv.conf, ensuring that it is the
+// first nameserver present.
+// Usable only with running containers.
+func (c *Container) addNameserver(ips []string) error {
+ // Take no action if container is not running.
+ if !c.ensureState(define.ContainerStateRunning, define.ContainerStateCreated) {
+ return nil
+ }
+
+ // Do we have a resolv.conf at all?
+ path, ok := c.state.BindMounts["/etc/resolv.conf"]
+ if !ok {
+ return nil
+ }
+
+ // Read in full contents, parse out existing nameservers
+ contents, err := ioutil.ReadFile(path)
+ if err != nil {
+ return err
+ }
+ ns := resolvconf.GetNameservers(contents)
+ options := resolvconf.GetOptions(contents)
+ search := resolvconf.GetSearchDomains(contents)
+
+ // We could verify that it doesn't already exist
+ // but extra nameservers shouldn't harm anything.
+ // Ensure we are the first entry in resolv.conf though, otherwise we
+ // might be after user-added servers.
+ ns = append(ips, ns...)
+
+ // We're rewriting the container's resolv.conf as part of this, but we
+ // hold the container lock, so there should be no risk of parallel
+ // modification.
+ if _, err := resolvconf.Build(path, ns, search, options); err != nil {
+ return errors.Wrapf(err, "error adding new nameserver to container %s resolv.conf", c.ID())
+ }
+
+ return nil
+}
+
+// Remove an entry from the existing resolv.conf of the container.
+// Usable only with running containers.
+func (c *Container) removeNameserver(ips []string) error {
+ // Take no action if container is not running.
+ if !c.ensureState(define.ContainerStateRunning, define.ContainerStateCreated) {
+ return nil
+ }
+
+ // Do we have a resolv.conf at all?
+ path, ok := c.state.BindMounts["/etc/resolv.conf"]
+ if !ok {
+ return nil
+ }
+
+ // Read in full contents, parse out existing nameservers
+ contents, err := ioutil.ReadFile(path)
+ if err != nil {
+ return err
+ }
+ ns := resolvconf.GetNameservers(contents)
+ options := resolvconf.GetOptions(contents)
+ search := resolvconf.GetSearchDomains(contents)
+
+ toRemove := make(map[string]bool)
+ for _, ip := range ips {
+ toRemove[ip] = true
+ }
+
+ newNS := make([]string, 0, len(ns))
+ for _, server := range ns {
+ if !toRemove[server] {
+ newNS = append(newNS, server)
+ }
+ }
+
+ if _, err := resolvconf.Build(path, newNS, search, options); err != nil {
+ return errors.Wrapf(err, "error removing nameservers from container %s resolv.conf", c.ID())
+ }
+
+ return nil
+}
+
// updateHosts updates the container's hosts file
func (c *Container) updateHosts(path string) error {
var hosts string
diff --git a/libpod/networking_linux.go b/libpod/networking_linux.go
index e55e9d114..19d5c7f76 100644
--- a/libpod/networking_linux.go
+++ b/libpod/networking_linux.go
@@ -1170,6 +1170,7 @@ func (c *Container) NetworkDisconnect(nameOrID, netName string, force bool) erro
}
// update network status if container is running
+ oldStatus, statusExist := networkStatus[netName]
delete(networkStatus, netName)
c.state.NetworkStatus = networkStatus
err = c.save()
@@ -1180,8 +1181,26 @@ func (c *Container) NetworkDisconnect(nameOrID, netName string, force bool) erro
// Reload ports when there are still connected networks, maybe we removed the network interface with the child ip.
// Reloading without connected networks does not make sense, so we can skip this step.
if rootless.IsRootless() && len(networkStatus) > 0 {
- return c.reloadRootlessRLKPortMapping()
+ if err := c.reloadRootlessRLKPortMapping(); err != nil {
+ return err
+ }
+ }
+
+ // Update resolv.conf if required
+ if statusExist {
+ stringIPs := make([]string, 0, len(oldStatus.DNSServerIPs))
+ for _, ip := range oldStatus.DNSServerIPs {
+ stringIPs = append(stringIPs, ip.String())
+ }
+ if len(stringIPs) == 0 {
+ return nil
+ }
+ logrus.Debugf("Removing DNS Servers %v from resolv.conf", stringIPs)
+ if err := c.removeNameserver(stringIPs); err != nil {
+ return err
+ }
}
+
return nil
}
@@ -1263,11 +1282,36 @@ func (c *Container) NetworkConnect(nameOrID, netName string, netOpts types.PerNe
if err != nil {
return err
}
+
// The first network needs a port reload to set the correct child ip for the rootlessport process.
// Adding a second network does not require a port reload because the child ip is still valid.
if rootless.IsRootless() && len(networks) == 0 {
- return c.reloadRootlessRLKPortMapping()
+ if err := c.reloadRootlessRLKPortMapping(); err != nil {
+ return err
+ }
}
+
+ ipv6, err := c.checkForIPv6(networkStatus)
+ if err != nil {
+ return err
+ }
+
+ // Update resolv.conf if required
+ stringIPs := make([]string, 0, len(results[netName].DNSServerIPs))
+ for _, ip := range results[netName].DNSServerIPs {
+ if (ip.To4() == nil) && !ipv6 {
+ continue
+ }
+ stringIPs = append(stringIPs, ip.String())
+ }
+ if len(stringIPs) == 0 {
+ return nil
+ }
+ logrus.Debugf("Adding DNS Servers %v to resolv.conf", stringIPs)
+ if err := c.addNameserver(stringIPs); err != nil {
+ return err
+ }
+
return nil
}
diff --git a/test/e2e/network_connect_disconnect_test.go b/test/e2e/network_connect_disconnect_test.go
index baef142ba..a0716c84d 100644
--- a/test/e2e/network_connect_disconnect_test.go
+++ b/test/e2e/network_connect_disconnect_test.go
@@ -2,6 +2,7 @@ package integration
import (
"os"
+ "strings"
. "github.com/containers/podman/v4/test/utils"
"github.com/containers/storage/pkg/stringid"
@@ -77,6 +78,11 @@ var _ = Describe("Podman network connect and disconnect", func() {
Expect(session).Should(Exit(0))
defer podmanTest.removeNetwork(netName)
+ gw := podmanTest.Podman([]string{"network", "inspect", netName, "--format", "{{(index .Subnets 0).Gateway}}"})
+ gw.WaitWithDefaultTimeout()
+ Expect(gw).Should(Exit(0))
+ ns := gw.OutputToString()
+
ctr := podmanTest.Podman([]string{"run", "-dt", "--name", "test", "--network", netName, ALPINE, "top"})
ctr.WaitWithDefaultTimeout()
Expect(ctr).Should(Exit(0))
@@ -85,6 +91,11 @@ var _ = Describe("Podman network connect and disconnect", func() {
exec.WaitWithDefaultTimeout()
Expect(exec).Should(Exit(0))
+ exec2 := podmanTest.Podman([]string{"exec", "-it", "test", "cat", "/etc/resolv.conf"})
+ exec2.WaitWithDefaultTimeout()
+ Expect(exec2).Should(Exit(0))
+ Expect(strings.Contains(exec2.OutputToString(), ns)).To(BeTrue())
+
dis := podmanTest.Podman([]string{"network", "disconnect", netName, "test"})
dis.WaitWithDefaultTimeout()
Expect(dis).Should(Exit(0))
@@ -98,6 +109,11 @@ var _ = Describe("Podman network connect and disconnect", func() {
exec = podmanTest.Podman([]string{"exec", "-it", "test", "ip", "addr", "show", "eth0"})
exec.WaitWithDefaultTimeout()
Expect(exec).Should(ExitWithError())
+
+ exec3 := podmanTest.Podman([]string{"exec", "-it", "test", "cat", "/etc/resolv.conf"})
+ exec3.WaitWithDefaultTimeout()
+ Expect(exec3).Should(Exit(0))
+ Expect(strings.Contains(exec3.OutputToString(), ns)).To(BeFalse())
})
It("bad network name in connect should result in error", func() {
@@ -182,6 +198,16 @@ var _ = Describe("Podman network connect and disconnect", func() {
Expect(session).Should(Exit(0))
defer podmanTest.removeNetwork(newNetName)
+ gw := podmanTest.Podman([]string{"network", "inspect", newNetName, "--format", "{{(index .Subnets 0).Gateway}}"})
+ gw.WaitWithDefaultTimeout()
+ Expect(gw).Should(Exit(0))
+ ns := gw.OutputToString()
+
+ exec2 := podmanTest.Podman([]string{"exec", "-it", "test", "cat", "/etc/resolv.conf"})
+ exec2.WaitWithDefaultTimeout()
+ Expect(exec2).Should(Exit(0))
+ Expect(strings.Contains(exec2.OutputToString(), ns)).To(BeFalse())
+
ip := "10.11.100.99"
mac := "44:11:44:11:44:11"
connect := podmanTest.Podman([]string{"network", "connect", "--ip", ip, "--mac-address", mac, newNetName, "test"})
@@ -206,6 +232,11 @@ var _ = Describe("Podman network connect and disconnect", func() {
Expect(exec.OutputToString()).Should(ContainSubstring(ip))
Expect(exec.OutputToString()).Should(ContainSubstring(mac))
+ exec3 := podmanTest.Podman([]string{"exec", "-it", "test", "cat", "/etc/resolv.conf"})
+ exec3.WaitWithDefaultTimeout()
+ Expect(exec3).Should(Exit(0))
+ Expect(strings.Contains(exec3.OutputToString(), ns)).To(BeTrue())
+
// make sure no logrus errors are shown https://github.com/containers/podman/issues/9602
rm := podmanTest.Podman([]string{"rm", "--time=0", "-f", "test"})
rm.WaitWithDefaultTimeout()