Ejemplo n.º 1
0
// configureBridge attempts to create and configure a network bridge interface named `bridgeIface` on the host
// If bridgeIP is empty, it will try to find a non-conflicting IP from the Docker-specified private ranges
// If the bridge `bridgeIface` already exists, it will only perform the IP address association with the existing
// bridge (fixes issue #8444)
// If an address which doesn't conflict with existing interfaces can't be found, an error is returned.
func configureBridge(bridgeIP string, bridgeIPv6 string, enableIPv6 bool) error {
	nameservers := []string{}
	resolvConf, _ := resolvconf.Get()
	// We don't check for an error here, because we don't really care
	// if we can't read /etc/resolv.conf. So instead we skip the append
	// if resolvConf is nil. It either doesn't exist, or we can't read it
	// for some reason.
	if resolvConf != nil {
		nameservers = append(nameservers, resolvconf.GetNameserversAsCIDR(resolvConf)...)
	}

	var ifaceAddr string
	if len(bridgeIP) != 0 {
		_, _, err := net.ParseCIDR(bridgeIP)
		if err != nil {
			return err
		}
		ifaceAddr = bridgeIP
	} else {
		for _, addr := range addrs {
			_, dockerNetwork, err := net.ParseCIDR(addr)
			if err != nil {
				return err
			}
			if err := networkdriver.CheckNameserverOverlaps(nameservers, dockerNetwork); err == nil {
				if err := networkdriver.CheckRouteOverlaps(dockerNetwork); err == nil {
					ifaceAddr = addr
					break
				} else {
					logrus.Debugf("%s %s", addr, err)
				}
			}
		}
	}

	if ifaceAddr == "" {
		return fmt.Errorf("Could not find a free IP address range for interface '%s'. Please configure its address manually and run 'docker -b %s'", bridgeIface, bridgeIface)
	}
	logrus.Debugf("Creating bridge %s with network %s", bridgeIface, ifaceAddr)

	if err := createBridgeIface(bridgeIface); err != nil {
		// The bridge may already exist, therefore we can ignore an "exists" error
		if !os.IsExist(err) {
			return err
		}
	}

	iface, err := net.InterfaceByName(bridgeIface)
	if err != nil {
		return err
	}

	ipAddr, ipNet, err := net.ParseCIDR(ifaceAddr)
	if err != nil {
		return err
	}

	if err := netlink.NetworkLinkAddIp(iface, ipAddr, ipNet); err != nil {
		return fmt.Errorf("Unable to add private network: %s", err)
	}

	if enableIPv6 {
		if err := setupIPv6Bridge(bridgeIPv6); err != nil {
			return err
		}
	}

	if err := netlink.NetworkLinkUp(iface); err != nil {
		return fmt.Errorf("Unable to start network bridge: %s", err)
	}
	return nil
}
Ejemplo n.º 2
0
func (container *Container) setupContainerDns() error {
	if container.ResolvConfPath != "" {
		// check if this is an existing container that needs DNS update:
		if container.UpdateDns {
			// read the host's resolv.conf, get the hash and call updateResolvConf
			logrus.Debugf("Check container (%s) for update to resolv.conf - UpdateDns flag was set", container.ID)
			latestResolvConf, latestHash := resolvconf.GetLastModified()

			// clean container resolv.conf re: localhost nameservers and IPv6 NS (if IPv6 disabled)
			updatedResolvConf, modified := resolvconf.FilterResolvDns(latestResolvConf, container.daemon.config.Bridge.EnableIPv6)
			if modified {
				// changes have occurred during resolv.conf localhost cleanup: generate an updated hash
				newHash, err := ioutils.HashData(bytes.NewReader(updatedResolvConf))
				if err != nil {
					return err
				}
				latestHash = newHash
			}

			if err := container.updateResolvConf(updatedResolvConf, latestHash); err != nil {
				return err
			}
			// successful update of the restarting container; set the flag off
			container.UpdateDns = false
		}
		return nil
	}

	var (
		config = container.hostConfig
		daemon = container.daemon
	)

	resolvConf, err := resolvconf.Get()
	if err != nil {
		return err
	}
	container.ResolvConfPath, err = container.GetRootResourcePath("resolv.conf")
	if err != nil {
		return err
	}

	if config.NetworkMode != "host" {
		// check configurations for any container/daemon dns settings
		if len(config.Dns) > 0 || len(daemon.config.Dns) > 0 || len(config.DnsSearch) > 0 || len(daemon.config.DnsSearch) > 0 {
			var (
				dns       = resolvconf.GetNameservers(resolvConf)
				dnsSearch = resolvconf.GetSearchDomains(resolvConf)
			)
			if len(config.Dns) > 0 {
				dns = config.Dns
			} else if len(daemon.config.Dns) > 0 {
				dns = daemon.config.Dns
			}
			if len(config.DnsSearch) > 0 {
				dnsSearch = config.DnsSearch
			} else if len(daemon.config.DnsSearch) > 0 {
				dnsSearch = daemon.config.DnsSearch
			}
			return resolvconf.Build(container.ResolvConfPath, dns, dnsSearch)
		}

		// replace any localhost/127.*, and remove IPv6 nameservers if IPv6 disabled in daemon
		resolvConf, _ = resolvconf.FilterResolvDns(resolvConf, daemon.config.Bridge.EnableIPv6)
	}
	//get a sha256 hash of the resolv conf at this point so we can check
	//for changes when the host resolv.conf changes (e.g. network update)
	resolvHash, err := ioutils.HashData(bytes.NewReader(resolvConf))
	if err != nil {
		return err
	}
	resolvHashFile := container.ResolvConfPath + ".hash"
	if err = ioutil.WriteFile(resolvHashFile, []byte(resolvHash), 0644); err != nil {
		return err
	}
	return ioutil.WriteFile(container.ResolvConfPath, resolvConf, 0644)
}