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moby--moby/daemon/networkdriver/bridge/driver.go
Phil Estes 0c8d17b5c1 Fix bridge initialization for IPv6 if IPv4-only docker0 exists
This fixes the daemon's failure to start when setting --ipv6=true for
the first time without deleting `docker0` bridge from a prior use with
only IPv4 addressing.

The addition of the IPv6 bridge address is factored out into a separate
initialization routine which is called even if the bridge exists but no
IPv6 addresses are found.

Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
2015-01-27 23:54:26 -05:00

721 lines
21 KiB
Go

package bridge
import (
"encoding/hex"
"errors"
"fmt"
"io/ioutil"
"net"
"os"
"strings"
"sync"
log "github.com/Sirupsen/logrus"
"github.com/docker/docker/daemon/networkdriver"
"github.com/docker/docker/daemon/networkdriver/ipallocator"
"github.com/docker/docker/daemon/networkdriver/portmapper"
"github.com/docker/docker/engine"
"github.com/docker/docker/nat"
"github.com/docker/docker/pkg/iptables"
"github.com/docker/docker/pkg/networkfs/resolvconf"
"github.com/docker/docker/pkg/parsers/kernel"
"github.com/docker/libcontainer/netlink"
)
const (
DefaultNetworkBridge = "docker0"
MaxAllocatedPortAttempts = 10
)
// Network interface represents the networking stack of a container
type networkInterface struct {
IP net.IP
IPv6 net.IP
PortMappings []net.Addr // there are mappings to the host interfaces
}
type ifaces struct {
c map[string]*networkInterface
sync.Mutex
}
func (i *ifaces) Set(key string, n *networkInterface) {
i.Lock()
i.c[key] = n
i.Unlock()
}
func (i *ifaces) Get(key string) *networkInterface {
i.Lock()
res := i.c[key]
i.Unlock()
return res
}
var (
addrs = []string{
// Here we don't follow the convention of using the 1st IP of the range for the gateway.
// This is to use the same gateway IPs as the /24 ranges, which predate the /16 ranges.
// In theory this shouldn't matter - in practice there's bound to be a few scripts relying
// on the internal addressing or other stupid things like that.
// They shouldn't, but hey, let's not break them unless we really have to.
"172.17.42.1/16", // Don't use 172.16.0.0/16, it conflicts with EC2 DNS 172.16.0.23
"10.0.42.1/16", // Don't even try using the entire /8, that's too intrusive
"10.1.42.1/16",
"10.42.42.1/16",
"172.16.42.1/24",
"172.16.43.1/24",
"172.16.44.1/24",
"10.0.42.1/24",
"10.0.43.1/24",
"192.168.42.1/24",
"192.168.43.1/24",
"192.168.44.1/24",
}
bridgeIface string
bridgeIPv4Network *net.IPNet
bridgeIPv6Addr net.IP
globalIPv6Network *net.IPNet
defaultBindingIP = net.ParseIP("0.0.0.0")
currentInterfaces = ifaces{c: make(map[string]*networkInterface)}
)
func InitDriver(job *engine.Job) engine.Status {
var (
networkv4 *net.IPNet
networkv6 *net.IPNet
addrv4 net.Addr
addrsv6 []net.Addr
enableIPTables = job.GetenvBool("EnableIptables")
enableIPv6 = job.GetenvBool("EnableIPv6")
icc = job.GetenvBool("InterContainerCommunication")
ipMasq = job.GetenvBool("EnableIpMasq")
ipForward = job.GetenvBool("EnableIpForward")
bridgeIP = job.Getenv("BridgeIP")
bridgeIPv6 = "fe80::1/64"
fixedCIDR = job.Getenv("FixedCIDR")
fixedCIDRv6 = job.Getenv("FixedCIDRv6")
)
if defaultIP := job.Getenv("DefaultBindingIP"); defaultIP != "" {
defaultBindingIP = net.ParseIP(defaultIP)
}
bridgeIface = job.Getenv("BridgeIface")
usingDefaultBridge := false
if bridgeIface == "" {
usingDefaultBridge = true
bridgeIface = DefaultNetworkBridge
}
addrv4, addrsv6, err := networkdriver.GetIfaceAddr(bridgeIface)
if err != nil {
// No Bridge existent. Create one
// If we're not using the default bridge, fail without trying to create it
if !usingDefaultBridge {
return job.Error(err)
}
// If the iface is not found, try to create it
if err := configureBridge(bridgeIP, bridgeIPv6, enableIPv6); err != nil {
return job.Error(err)
}
addrv4, addrsv6, err = networkdriver.GetIfaceAddr(bridgeIface)
if err != nil {
return job.Error(err)
}
if fixedCIDRv6 != "" {
// Setting route to global IPv6 subnet
log.Infof("Adding route to IPv6 network %q via device %q", fixedCIDRv6, bridgeIface)
if err := netlink.AddRoute(fixedCIDRv6, "", "", bridgeIface); err != nil {
log.Fatalf("Could not add route to IPv6 network %q via device %q", fixedCIDRv6, bridgeIface)
}
}
} else {
// Bridge exists already. Getting info...
// validate that the bridge ip matches the ip specified by BridgeIP
if bridgeIP != "" {
networkv4 = addrv4.(*net.IPNet)
bip, _, err := net.ParseCIDR(bridgeIP)
if err != nil {
return job.Error(err)
}
if !networkv4.IP.Equal(bip) {
return job.Errorf("bridge ip (%s) does not match existing bridge configuration %s", networkv4.IP, bip)
}
}
// a bridge might exist but not have any IPv6 addr associated with it yet
// (for example, an existing Docker installation that has only been used
// with IPv4 and docker0 already is set up) In that case, we can perform
// the bridge init for IPv6 here, else we will error out below if --ipv6=true
if len(addrsv6) == 0 && enableIPv6 {
if err := setupIPv6Bridge(bridgeIPv6); err != nil {
return job.Error(err)
}
// recheck addresses now that IPv6 is setup on the bridge
addrv4, addrsv6, err = networkdriver.GetIfaceAddr(bridgeIface)
if err != nil {
return job.Error(err)
}
}
// TODO: Check if route to fixedCIDRv6 is set
}
if enableIPv6 {
bip6, _, err := net.ParseCIDR(bridgeIPv6)
if err != nil {
return job.Error(err)
}
found := false
for _, addrv6 := range addrsv6 {
networkv6 = addrv6.(*net.IPNet)
if networkv6.IP.Equal(bip6) {
found = true
break
}
}
if !found {
return job.Errorf("bridge IPv6 does not match existing bridge configuration %s", bip6)
}
}
networkv4 = addrv4.(*net.IPNet)
log.Infof("enableIPv6 = %t", enableIPv6)
if enableIPv6 {
if len(addrsv6) == 0 {
return job.Error(errors.New("IPv6 enabled but no IPv6 detected"))
}
bridgeIPv6Addr = networkv6.IP
}
// Configure iptables for link support
if enableIPTables {
if err := setupIPTables(addrv4, icc, ipMasq); err != nil {
return job.Error(err)
}
}
if ipForward {
// Enable IPv4 forwarding
if err := ioutil.WriteFile("/proc/sys/net/ipv4/ip_forward", []byte{'1', '\n'}, 0644); err != nil {
job.Logf("WARNING: unable to enable IPv4 forwarding: %s\n", err)
}
if fixedCIDRv6 != "" {
// Enable IPv6 forwarding
if err := ioutil.WriteFile("/proc/sys/net/ipv6/conf/default/forwarding", []byte{'1', '\n'}, 0644); err != nil {
job.Logf("WARNING: unable to enable IPv6 default forwarding: %s\n", err)
}
if err := ioutil.WriteFile("/proc/sys/net/ipv6/conf/all/forwarding", []byte{'1', '\n'}, 0644); err != nil {
job.Logf("WARNING: unable to enable IPv6 all forwarding: %s\n", err)
}
}
}
// We can always try removing the iptables
if err := iptables.RemoveExistingChain("DOCKER", iptables.Nat); err != nil {
return job.Error(err)
}
if enableIPTables {
_, err := iptables.NewChain("DOCKER", bridgeIface, iptables.Nat)
if err != nil {
return job.Error(err)
}
chain, err := iptables.NewChain("DOCKER", bridgeIface, iptables.Filter)
if err != nil {
return job.Error(err)
}
portmapper.SetIptablesChain(chain)
}
bridgeIPv4Network = networkv4
if fixedCIDR != "" {
_, subnet, err := net.ParseCIDR(fixedCIDR)
if err != nil {
return job.Error(err)
}
log.Debugf("Subnet: %v", subnet)
if err := ipallocator.RegisterSubnet(bridgeIPv4Network, subnet); err != nil {
return job.Error(err)
}
}
if fixedCIDRv6 != "" {
_, subnet, err := net.ParseCIDR(fixedCIDRv6)
if err != nil {
return job.Error(err)
}
log.Debugf("Subnet: %v", subnet)
if err := ipallocator.RegisterSubnet(subnet, subnet); err != nil {
return job.Error(err)
}
globalIPv6Network = subnet
}
// Block BridgeIP in IP allocator
ipallocator.RequestIP(bridgeIPv4Network, bridgeIPv4Network.IP)
// https://github.com/docker/docker/issues/2768
job.Eng.Hack_SetGlobalVar("httpapi.bridgeIP", bridgeIPv4Network.IP)
for name, f := range map[string]engine.Handler{
"allocate_interface": Allocate,
"release_interface": Release,
"allocate_port": AllocatePort,
"link": LinkContainers,
} {
if err := job.Eng.Register(name, f); err != nil {
return job.Error(err)
}
}
return engine.StatusOK
}
func setupIPTables(addr net.Addr, icc, ipmasq bool) error {
// Enable NAT
if ipmasq {
natArgs := []string{"POSTROUTING", "-t", "nat", "-s", addr.String(), "!", "-o", bridgeIface, "-j", "MASQUERADE"}
if !iptables.Exists(natArgs...) {
if output, err := iptables.Raw(append([]string{"-I"}, natArgs...)...); err != nil {
return fmt.Errorf("Unable to enable network bridge NAT: %s", err)
} else if len(output) != 0 {
return &iptables.ChainError{Chain: "POSTROUTING", Output: output}
}
}
}
var (
args = []string{"FORWARD", "-i", bridgeIface, "-o", bridgeIface, "-j"}
acceptArgs = append(args, "ACCEPT")
dropArgs = append(args, "DROP")
)
if !icc {
iptables.Raw(append([]string{"-D"}, acceptArgs...)...)
if !iptables.Exists(dropArgs...) {
log.Debugf("Disable inter-container communication")
if output, err := iptables.Raw(append([]string{"-I"}, dropArgs...)...); err != nil {
return fmt.Errorf("Unable to prevent intercontainer communication: %s", err)
} else if len(output) != 0 {
return fmt.Errorf("Error disabling intercontainer communication: %s", output)
}
}
} else {
iptables.Raw(append([]string{"-D"}, dropArgs...)...)
if !iptables.Exists(acceptArgs...) {
log.Debugf("Enable inter-container communication")
if output, err := iptables.Raw(append([]string{"-I"}, acceptArgs...)...); err != nil {
return fmt.Errorf("Unable to allow intercontainer communication: %s", err)
} else if len(output) != 0 {
return fmt.Errorf("Error enabling intercontainer communication: %s", output)
}
}
}
// Accept all non-intercontainer outgoing packets
outgoingArgs := []string{"FORWARD", "-i", bridgeIface, "!", "-o", bridgeIface, "-j", "ACCEPT"}
if !iptables.Exists(outgoingArgs...) {
if output, err := iptables.Raw(append([]string{"-I"}, outgoingArgs...)...); err != nil {
return fmt.Errorf("Unable to allow outgoing packets: %s", err)
} else if len(output) != 0 {
return &iptables.ChainError{Chain: "FORWARD outgoing", Output: output}
}
}
// Accept incoming packets for existing connections
existingArgs := []string{"FORWARD", "-o", bridgeIface, "-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"}
if !iptables.Exists(existingArgs...) {
if output, err := iptables.Raw(append([]string{"-I"}, existingArgs...)...); err != nil {
return fmt.Errorf("Unable to allow incoming packets: %s", err)
} else if len(output) != 0 {
return &iptables.ChainError{Chain: "FORWARD incoming", Output: output}
}
}
return nil
}
// 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 {
log.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)
}
log.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
}
func setupIPv6Bridge(bridgeIPv6 string) error {
iface, err := net.InterfaceByName(bridgeIface)
if err != nil {
return err
}
// Enable IPv6 on the bridge
procFile := "/proc/sys/net/ipv6/conf/" + iface.Name + "/disable_ipv6"
if err := ioutil.WriteFile(procFile, []byte{'0', '\n'}, 0644); err != nil {
return fmt.Errorf("Unable to enable IPv6 addresses on bridge: %v", err)
}
ipAddr6, ipNet6, err := net.ParseCIDR(bridgeIPv6)
if err != nil {
return fmt.Errorf("Unable to parse bridge IPv6 address: %q, error: %v", bridgeIPv6, err)
}
if err := netlink.NetworkLinkAddIp(iface, ipAddr6, ipNet6); err != nil {
return fmt.Errorf("Unable to add private IPv6 network: %v", err)
}
return nil
}
func createBridgeIface(name string) error {
kv, err := kernel.GetKernelVersion()
// only set the bridge's mac address if the kernel version is > 3.3
// before that it was not supported
setBridgeMacAddr := err == nil && (kv.Kernel >= 3 && kv.Major >= 3)
log.Debugf("setting bridge mac address = %v", setBridgeMacAddr)
return netlink.CreateBridge(name, setBridgeMacAddr)
}
// Generate a IEEE802 compliant MAC address from the given IP address.
//
// The generator is guaranteed to be consistent: the same IP will always yield the same
// MAC address. This is to avoid ARP cache issues.
func generateMacAddr(ip net.IP) net.HardwareAddr {
hw := make(net.HardwareAddr, 6)
// The first byte of the MAC address has to comply with these rules:
// 1. Unicast: Set the least-significant bit to 0.
// 2. Address is locally administered: Set the second-least-significant bit (U/L) to 1.
// 3. As "small" as possible: The veth address has to be "smaller" than the bridge address.
hw[0] = 0x02
// The first 24 bits of the MAC represent the Organizationally Unique Identifier (OUI).
// Since this address is locally administered, we can do whatever we want as long as
// it doesn't conflict with other addresses.
hw[1] = 0x42
// Insert the IP address into the last 32 bits of the MAC address.
// This is a simple way to guarantee the address will be consistent and unique.
copy(hw[2:], ip.To4())
return hw
}
func linkLocalIPv6FromMac(mac string) (string, error) {
hx := strings.Replace(mac, ":", "", -1)
hw, err := hex.DecodeString(hx)
if err != nil {
return "", errors.New("Could not parse MAC address " + mac)
}
hw[0] ^= 0x2
return fmt.Sprintf("fe80::%x%x:%xff:fe%x:%x%x/64", hw[0], hw[1], hw[2], hw[3], hw[4], hw[5]), nil
}
// Allocate a network interface
func Allocate(job *engine.Job) engine.Status {
var (
ip net.IP
mac net.HardwareAddr
err error
id = job.Args[0]
requestedIP = net.ParseIP(job.Getenv("RequestedIP"))
requestedIPv6 = net.ParseIP(job.Getenv("RequestedIPv6"))
globalIPv6 net.IP
)
if requestedIP != nil {
ip, err = ipallocator.RequestIP(bridgeIPv4Network, requestedIP)
} else {
ip, err = ipallocator.RequestIP(bridgeIPv4Network, nil)
}
if err != nil {
return job.Error(err)
}
// If no explicit mac address was given, generate a random one.
if mac, err = net.ParseMAC(job.Getenv("RequestedMac")); err != nil {
mac = generateMacAddr(ip)
}
if globalIPv6Network != nil {
// if globalIPv6Network Size is at least a /80 subnet generate IPv6 address from MAC address
netmask_ones, _ := globalIPv6Network.Mask.Size()
if requestedIPv6 == nil && netmask_ones <= 80 {
requestedIPv6 = globalIPv6Network.IP
for i, h := range mac {
requestedIPv6[i+10] = h
}
}
globalIPv6, err = ipallocator.RequestIP(globalIPv6Network, requestedIPv6)
if err != nil {
log.Errorf("Allocator: RequestIP v6: %s", err.Error())
return job.Error(err)
}
log.Infof("Allocated IPv6 %s", globalIPv6)
}
out := engine.Env{}
out.Set("IP", ip.String())
out.Set("Mask", bridgeIPv4Network.Mask.String())
out.Set("Gateway", bridgeIPv4Network.IP.String())
out.Set("MacAddress", mac.String())
out.Set("Bridge", bridgeIface)
size, _ := bridgeIPv4Network.Mask.Size()
out.SetInt("IPPrefixLen", size)
// if linklocal IPv6
localIPv6Net, err := linkLocalIPv6FromMac(mac.String())
if err != nil {
return job.Error(err)
}
localIPv6, _, _ := net.ParseCIDR(localIPv6Net)
out.Set("LinkLocalIPv6", localIPv6.String())
out.Set("MacAddress", mac.String())
if globalIPv6Network != nil {
out.Set("GlobalIPv6", globalIPv6.String())
sizev6, _ := globalIPv6Network.Mask.Size()
out.SetInt("GlobalIPv6PrefixLen", sizev6)
out.Set("IPv6Gateway", bridgeIPv6Addr.String())
}
currentInterfaces.Set(id, &networkInterface{
IP: ip,
IPv6: globalIPv6,
})
out.WriteTo(job.Stdout)
return engine.StatusOK
}
// release an interface for a select ip
func Release(job *engine.Job) engine.Status {
var (
id = job.Args[0]
containerInterface = currentInterfaces.Get(id)
)
if containerInterface == nil {
return job.Errorf("No network information to release for %s", id)
}
for _, nat := range containerInterface.PortMappings {
if err := portmapper.Unmap(nat); err != nil {
log.Infof("Unable to unmap port %s: %s", nat, err)
}
}
if err := ipallocator.ReleaseIP(bridgeIPv4Network, containerInterface.IP); err != nil {
log.Infof("Unable to release IPv4 %s", err)
}
if globalIPv6Network != nil {
if err := ipallocator.ReleaseIP(globalIPv6Network, containerInterface.IPv6); err != nil {
log.Infof("Unable to release IPv6 %s", err)
}
}
return engine.StatusOK
}
// Allocate an external port and map it to the interface
func AllocatePort(job *engine.Job) engine.Status {
var (
err error
ip = defaultBindingIP
id = job.Args[0]
hostIP = job.Getenv("HostIP")
hostPort = job.GetenvInt("HostPort")
containerPort = job.GetenvInt("ContainerPort")
proto = job.Getenv("Proto")
network = currentInterfaces.Get(id)
)
if hostIP != "" {
ip = net.ParseIP(hostIP)
if ip == nil {
return job.Errorf("Bad parameter: invalid host ip %s", hostIP)
}
}
// host ip, proto, and host port
var container net.Addr
switch proto {
case "tcp":
container = &net.TCPAddr{IP: network.IP, Port: containerPort}
case "udp":
container = &net.UDPAddr{IP: network.IP, Port: containerPort}
default:
return job.Errorf("unsupported address type %s", proto)
}
//
// Try up to 10 times to get a port that's not already allocated.
//
// In the event of failure to bind, return the error that portmapper.Map
// yields.
//
var host net.Addr
for i := 0; i < MaxAllocatedPortAttempts; i++ {
if host, err = portmapper.Map(container, ip, hostPort); err == nil {
break
}
// There is no point in immediately retrying to map an explicitly
// chosen port.
if hostPort != 0 {
job.Logf("Failed to allocate and map port %d: %s", hostPort, err)
break
}
job.Logf("Failed to allocate and map port: %s, retry: %d", err, i+1)
}
if err != nil {
return job.Error(err)
}
network.PortMappings = append(network.PortMappings, host)
out := engine.Env{}
switch netAddr := host.(type) {
case *net.TCPAddr:
out.Set("HostIP", netAddr.IP.String())
out.SetInt("HostPort", netAddr.Port)
case *net.UDPAddr:
out.Set("HostIP", netAddr.IP.String())
out.SetInt("HostPort", netAddr.Port)
}
if _, err := out.WriteTo(job.Stdout); err != nil {
return job.Error(err)
}
return engine.StatusOK
}
func LinkContainers(job *engine.Job) engine.Status {
var (
action = job.Args[0]
nfAction iptables.Action
childIP = job.Getenv("ChildIP")
parentIP = job.Getenv("ParentIP")
ignoreErrors = job.GetenvBool("IgnoreErrors")
ports = job.GetenvList("Ports")
)
switch action {
case "-A":
nfAction = iptables.Append
case "-I":
nfAction = iptables.Insert
case "-D":
nfAction = iptables.Delete
default:
return job.Errorf("Invalid action '%s' specified", action)
}
ip1 := net.ParseIP(parentIP)
if ip1 == nil {
return job.Errorf("parent IP '%s' is invalid", parentIP)
}
ip2 := net.ParseIP(childIP)
if ip2 == nil {
return job.Errorf("child IP '%s' is invalid", childIP)
}
chain := iptables.Chain{Name: "DOCKER", Bridge: bridgeIface}
for _, p := range ports {
port := nat.Port(p)
if err := chain.Link(nfAction, ip1, ip2, port.Int(), port.Proto()); !ignoreErrors && err != nil {
return job.Error(err)
}
}
return engine.StatusOK
}