mirror of
https://github.com/moby/moby.git
synced 2026-07-13 02:52:20 +00:00
89470a7114
Since964ab7158c, we explicitly set the bridge MTU if it was specified. Unfortunately, kernel <v4.17 have a check preventing us to manually set the MTU to anything greater than 1500 if no links is attached to the bridge, which is how we do things -- create the bridge, set its MTU and later on, attach veths to it. Relevant kernel commit:804b854d37As we still have to support CentOS/RHEL 7 (and their old v3.10 kernels) for a few more months, we need to ignore EINVAL if the MTU is > 1500 (but <= 65535). Signed-off-by: Albin Kerouanton <albinker@gmail.com>
98 lines
3.4 KiB
Go
98 lines
3.4 KiB
Go
package bridge
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"fmt"
|
|
"os"
|
|
"path/filepath"
|
|
"syscall"
|
|
|
|
"github.com/containerd/log"
|
|
"github.com/docker/docker/libnetwork/netutils"
|
|
"github.com/vishvananda/netlink"
|
|
)
|
|
|
|
// SetupDevice create a new bridge interface/
|
|
func setupDevice(config *networkConfiguration, i *bridgeInterface) error {
|
|
// We only attempt to create the bridge when the requested device name is
|
|
// the default one. The default bridge name can be overridden with the
|
|
// DOCKER_TEST_CREATE_DEFAULT_BRIDGE env var. It should be used only for
|
|
// test purpose.
|
|
var defaultBridgeName string
|
|
if defaultBridgeName = os.Getenv("DOCKER_TEST_CREATE_DEFAULT_BRIDGE"); defaultBridgeName == "" {
|
|
defaultBridgeName = DefaultBridgeName
|
|
}
|
|
if config.BridgeName != defaultBridgeName && config.DefaultBridge {
|
|
return NonDefaultBridgeExistError(config.BridgeName)
|
|
}
|
|
|
|
// Set the bridgeInterface netlink.Bridge.
|
|
i.Link = &netlink.Bridge{
|
|
LinkAttrs: netlink.LinkAttrs{
|
|
Name: config.BridgeName,
|
|
},
|
|
}
|
|
|
|
// Set the bridge's MAC address. Requires kernel version 3.3 or up.
|
|
hwAddr := netutils.GenerateRandomMAC()
|
|
i.Link.Attrs().HardwareAddr = hwAddr
|
|
log.G(context.TODO()).Debugf("Setting bridge mac address to %s", hwAddr)
|
|
|
|
if err := i.nlh.LinkAdd(i.Link); err != nil {
|
|
log.G(context.TODO()).WithError(err).Errorf("Failed to create bridge %s via netlink", config.BridgeName)
|
|
return err
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func setupMTU(config *networkConfiguration, i *bridgeInterface) error {
|
|
if err := i.nlh.LinkSetMTU(i.Link, config.Mtu); err != nil {
|
|
// Before Linux v4.17, bridges couldn't be configured "manually" with an MTU greater than 1500, although it
|
|
// could be autoconfigured with such a value when interfaces were added to the bridge. In that case, the
|
|
// bridge MTU would be set automatically by the kernel to the lowest MTU of all interfaces attached. To keep
|
|
// compatibility with older kernels, we need to discard -EINVAL.
|
|
// TODO(aker): remove this once we drop support for CentOS/RHEL 7.
|
|
if config.Mtu > 1500 && config.Mtu <= 0xFFFF && errors.Is(err, syscall.EINVAL) {
|
|
return nil
|
|
}
|
|
log.G(context.TODO()).WithError(err).Errorf("Failed to set bridge MTU %s via netlink", config.BridgeName)
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func setupDefaultSysctl(config *networkConfiguration, i *bridgeInterface) error {
|
|
// Disable IPv6 router advertisements originating on the bridge
|
|
sysPath := filepath.Join("/proc/sys/net/ipv6/conf/", config.BridgeName, "accept_ra")
|
|
if _, err := os.Stat(sysPath); err != nil {
|
|
log.G(context.TODO()).
|
|
WithField("bridge", config.BridgeName).
|
|
WithField("syspath", sysPath).
|
|
Info("failed to read ipv6 net.ipv6.conf.<bridge>.accept_ra")
|
|
return nil
|
|
}
|
|
if err := os.WriteFile(sysPath, []byte{'0', '\n'}, 0o644); err != nil {
|
|
log.G(context.TODO()).WithError(err).Warn("unable to disable IPv6 router advertisement")
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// SetupDeviceUp ups the given bridge interface.
|
|
func setupDeviceUp(config *networkConfiguration, i *bridgeInterface) error {
|
|
err := i.nlh.LinkSetUp(i.Link)
|
|
if err != nil {
|
|
return fmt.Errorf("Failed to set link up for %s: %v", config.BridgeName, err)
|
|
}
|
|
|
|
// Attempt to update the bridge interface to refresh the flags status,
|
|
// ignoring any failure to do so.
|
|
if lnk, err := i.nlh.LinkByName(config.BridgeName); err == nil {
|
|
i.Link = lnk
|
|
} else {
|
|
log.G(context.TODO()).Warnf("Failed to retrieve link for interface (%s): %v", config.BridgeName, err)
|
|
}
|
|
return nil
|
|
}
|