github.com/adityamillind98/moby@v23.0.0-rc.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. 20 if config.BridgeName != DefaultBridgeName && config.DefaultBridge { 21 return NonDefaultBridgeExistError(config.BridgeName) 22 } 23 24 // Set the bridgeInterface netlink.Bridge. 25 i.Link = &netlink.Bridge{ 26 LinkAttrs: netlink.LinkAttrs{ 27 Name: config.BridgeName, 28 }, 29 } 30 31 // Set the bridge's MAC address. Requires kernel version 3.3 or up. 32 hwAddr := netutils.GenerateRandomMAC() 33 i.Link.Attrs().HardwareAddr = hwAddr 34 logrus.Debugf("Setting bridge mac address to %s", hwAddr) 35 36 if err := i.nlh.LinkAdd(i.Link); err != nil { 37 logrus.Debugf("Failed to create bridge %s via netlink. Trying ioctl", config.BridgeName) 38 return ioctlCreateBridge(config.BridgeName, hwAddr.String()) 39 } 40 41 return nil 42 } 43 44 func setupDefaultSysctl(config *networkConfiguration, i *bridgeInterface) error { 45 // Disable IPv6 router advertisements originating on the bridge 46 sysPath := filepath.Join("/proc/sys/net/ipv6/conf/", config.BridgeName, "accept_ra") 47 if _, err := os.Stat(sysPath); err != nil { 48 logrus. 49 WithField("bridge", config.BridgeName). 50 WithField("syspath", sysPath). 51 Info("failed to read ipv6 net.ipv6.conf.<bridge>.accept_ra") 52 return nil 53 } 54 if err := os.WriteFile(sysPath, []byte{'0', '\n'}, 0644); err != nil { 55 logrus.WithError(err).Warn("unable to disable IPv6 router advertisement") 56 } 57 return nil 58 } 59 60 // SetupDeviceUp ups the given bridge interface. 61 func setupDeviceUp(config *networkConfiguration, i *bridgeInterface) error { 62 err := i.nlh.LinkSetUp(i.Link) 63 if err != nil { 64 return fmt.Errorf("Failed to set link up for %s: %v", config.BridgeName, err) 65 } 66 67 // Attempt to update the bridge interface to refresh the flags status, 68 // ignoring any failure to do so. 69 if lnk, err := i.nlh.LinkByName(config.BridgeName); err == nil { 70 i.Link = lnk 71 } else { 72 logrus.Warnf("Failed to retrieve link for interface (%s): %v", config.BridgeName, err) 73 } 74 return nil 75 }