github.com/rawahars/moby@v24.0.4+incompatible/libnetwork/drivers/bridge/setup_device.go (about) 1 //go:build linux 2 // +build linux 3 4 package bridge 5 6 import ( 7 "fmt" 8 "os" 9 "path/filepath" 10 11 "github.com/docker/docker/libnetwork/netutils" 12 "github.com/sirupsen/logrus" 13 "github.com/vishvananda/netlink" 14 ) 15 16 // SetupDevice create a new bridge interface/ 17 func setupDevice(config *networkConfiguration, i *bridgeInterface) error { 18 // We only attempt to create the bridge when the requested device name is 19 // the default one. The default bridge name can be overridden with the 20 // DOCKER_TEST_CREATE_DEFAULT_BRIDGE env var. It should be used only for 21 // test purpose. 22 var defaultBridgeName string 23 if defaultBridgeName = os.Getenv("DOCKER_TEST_CREATE_DEFAULT_BRIDGE"); defaultBridgeName == "" { 24 defaultBridgeName = DefaultBridgeName 25 } 26 if config.BridgeName != defaultBridgeName && config.DefaultBridge { 27 return NonDefaultBridgeExistError(config.BridgeName) 28 } 29 30 // Set the bridgeInterface netlink.Bridge. 31 i.Link = &netlink.Bridge{ 32 LinkAttrs: netlink.LinkAttrs{ 33 Name: config.BridgeName, 34 }, 35 } 36 37 // Set the bridge's MAC address. Requires kernel version 3.3 or up. 38 hwAddr := netutils.GenerateRandomMAC() 39 i.Link.Attrs().HardwareAddr = hwAddr 40 logrus.Debugf("Setting bridge mac address to %s", hwAddr) 41 42 if err := i.nlh.LinkAdd(i.Link); err != nil { 43 logrus.WithError(err).Errorf("Failed to create bridge %s via netlink", config.BridgeName) 44 return err 45 } 46 47 return nil 48 } 49 50 func setupDefaultSysctl(config *networkConfiguration, i *bridgeInterface) error { 51 // Disable IPv6 router advertisements originating on the bridge 52 sysPath := filepath.Join("/proc/sys/net/ipv6/conf/", config.BridgeName, "accept_ra") 53 if _, err := os.Stat(sysPath); err != nil { 54 logrus. 55 WithField("bridge", config.BridgeName). 56 WithField("syspath", sysPath). 57 Info("failed to read ipv6 net.ipv6.conf.<bridge>.accept_ra") 58 return nil 59 } 60 if err := os.WriteFile(sysPath, []byte{'0', '\n'}, 0644); err != nil { 61 logrus.WithError(err).Warn("unable to disable IPv6 router advertisement") 62 } 63 return nil 64 } 65 66 // SetupDeviceUp ups the given bridge interface. 67 func setupDeviceUp(config *networkConfiguration, i *bridgeInterface) error { 68 err := i.nlh.LinkSetUp(i.Link) 69 if err != nil { 70 return fmt.Errorf("Failed to set link up for %s: %v", config.BridgeName, err) 71 } 72 73 // Attempt to update the bridge interface to refresh the flags status, 74 // ignoring any failure to do so. 75 if lnk, err := i.nlh.LinkByName(config.BridgeName); err == nil { 76 i.Link = lnk 77 } else { 78 logrus.Warnf("Failed to retrieve link for interface (%s): %v", config.BridgeName, err) 79 } 80 return nil 81 }