432 lines
14 KiB
Go
432 lines
14 KiB
Go
// +build linux
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package bridge
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import (
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"errors"
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"fmt"
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"net"
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"github.com/docker/docker/libnetwork/iptables"
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"github.com/sirupsen/logrus"
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"github.com/vishvananda/netlink"
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)
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// DockerChain: DOCKER iptable chain name
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const (
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DockerChain = "DOCKER"
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// Isolation between bridge networks is achieved in two stages by means
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// of the following two chains in the filter table. The first chain matches
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// on the source interface being a bridge network's bridge and the
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// destination being a different interface. A positive match leads to the
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// second isolation chain. No match returns to the parent chain. The second
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// isolation chain matches on destination interface being a bridge network's
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// bridge. A positive match identifies a packet originated from one bridge
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// network's bridge destined to another bridge network's bridge and will
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// result in the packet being dropped. No match returns to the parent chain.
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IsolationChain1 = "DOCKER-ISOLATION-STAGE-1"
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IsolationChain2 = "DOCKER-ISOLATION-STAGE-2"
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)
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func setupIPChains(config *configuration, version iptables.IPVersion) (*iptables.ChainInfo, *iptables.ChainInfo, *iptables.ChainInfo, *iptables.ChainInfo, error) {
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// Sanity check.
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if !config.EnableIPTables {
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return nil, nil, nil, nil, errors.New("cannot create new chains, EnableIPTable is disabled")
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}
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hairpinMode := !config.EnableUserlandProxy
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iptable := iptables.GetIptable(version)
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natChain, err := iptable.NewChain(DockerChain, iptables.Nat, hairpinMode)
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if err != nil {
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return nil, nil, nil, nil, fmt.Errorf("failed to create NAT chain %s: %v", DockerChain, err)
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}
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defer func() {
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if err != nil {
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if err := iptable.RemoveExistingChain(DockerChain, iptables.Nat); err != nil {
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logrus.Warnf("failed on removing iptables NAT chain %s on cleanup: %v", DockerChain, err)
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}
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}
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}()
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filterChain, err := iptable.NewChain(DockerChain, iptables.Filter, false)
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if err != nil {
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return nil, nil, nil, nil, fmt.Errorf("failed to create FILTER chain %s: %v", DockerChain, err)
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}
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defer func() {
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if err != nil {
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if err := iptable.RemoveExistingChain(DockerChain, iptables.Filter); err != nil {
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logrus.Warnf("failed on removing iptables FILTER chain %s on cleanup: %v", DockerChain, err)
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}
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}
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}()
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isolationChain1, err := iptable.NewChain(IsolationChain1, iptables.Filter, false)
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if err != nil {
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return nil, nil, nil, nil, fmt.Errorf("failed to create FILTER isolation chain: %v", err)
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}
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defer func() {
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if err != nil {
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if err := iptable.RemoveExistingChain(IsolationChain1, iptables.Filter); err != nil {
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logrus.Warnf("failed on removing iptables FILTER chain %s on cleanup: %v", IsolationChain1, err)
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}
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}
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}()
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isolationChain2, err := iptable.NewChain(IsolationChain2, iptables.Filter, false)
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if err != nil {
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return nil, nil, nil, nil, fmt.Errorf("failed to create FILTER isolation chain: %v", err)
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}
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defer func() {
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if err != nil {
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if err := iptable.RemoveExistingChain(IsolationChain2, iptables.Filter); err != nil {
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logrus.Warnf("failed on removing iptables FILTER chain %s on cleanup: %v", IsolationChain2, err)
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}
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}
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}()
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if err := iptable.AddReturnRule(IsolationChain1); err != nil {
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return nil, nil, nil, nil, err
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}
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if err := iptable.AddReturnRule(IsolationChain2); err != nil {
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return nil, nil, nil, nil, err
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}
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return natChain, filterChain, isolationChain1, isolationChain2, nil
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}
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func (n *bridgeNetwork) setupIP4Tables(config *networkConfiguration, i *bridgeInterface) error {
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d := n.driver
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d.Lock()
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driverConfig := d.config
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d.Unlock()
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// Sanity check.
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if !driverConfig.EnableIPTables {
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return errors.New("Cannot program chains, EnableIPTable is disabled")
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}
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maskedAddrv4 := &net.IPNet{
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IP: i.bridgeIPv4.IP.Mask(i.bridgeIPv4.Mask),
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Mask: i.bridgeIPv4.Mask,
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}
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return n.setupIPTables(iptables.IPv4, maskedAddrv4, config, i)
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}
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func (n *bridgeNetwork) setupIP6Tables(config *networkConfiguration, i *bridgeInterface) error {
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d := n.driver
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d.Lock()
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driverConfig := d.config
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d.Unlock()
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// Sanity check.
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if !driverConfig.EnableIP6Tables {
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return errors.New("Cannot program chains, EnableIP6Tables is disabled")
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}
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maskedAddrv6 := &net.IPNet{
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IP: i.bridgeIPv6.IP.Mask(i.bridgeIPv6.Mask),
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Mask: i.bridgeIPv6.Mask,
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}
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return n.setupIPTables(iptables.IPv6, maskedAddrv6, config, i)
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}
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func (n *bridgeNetwork) setupIPTables(ipVersion iptables.IPVersion, maskedAddr *net.IPNet, config *networkConfiguration, i *bridgeInterface) error {
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var err error
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d := n.driver
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d.Lock()
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driverConfig := d.config
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d.Unlock()
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// Pickup this configuration option from driver
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hairpinMode := !driverConfig.EnableUserlandProxy
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iptable := iptables.GetIptable(ipVersion)
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if config.Internal {
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if err = setupInternalNetworkRules(config.BridgeName, maskedAddr, config.EnableICC, true); err != nil {
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return fmt.Errorf("Failed to Setup IP tables: %s", err.Error())
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}
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n.registerIptCleanFunc(func() error {
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return setupInternalNetworkRules(config.BridgeName, maskedAddr, config.EnableICC, false)
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})
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} else {
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if err = setupIPTablesInternal(config.HostIP, config.BridgeName, maskedAddr, config.EnableICC, config.EnableIPMasquerade, hairpinMode, true); err != nil {
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return fmt.Errorf("Failed to Setup IP tables: %s", err.Error())
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}
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n.registerIptCleanFunc(func() error {
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return setupIPTablesInternal(config.HostIP, config.BridgeName, maskedAddr, config.EnableICC, config.EnableIPMasquerade, hairpinMode, false)
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})
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natChain, filterChain, _, _, err := n.getDriverChains(ipVersion)
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if err != nil {
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return fmt.Errorf("Failed to setup IP tables, cannot acquire chain info %s", err.Error())
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}
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err = iptable.ProgramChain(natChain, config.BridgeName, hairpinMode, true)
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if err != nil {
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return fmt.Errorf("Failed to program NAT chain: %s", err.Error())
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}
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err = iptable.ProgramChain(filterChain, config.BridgeName, hairpinMode, true)
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if err != nil {
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return fmt.Errorf("Failed to program FILTER chain: %s", err.Error())
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}
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n.registerIptCleanFunc(func() error {
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return iptable.ProgramChain(filterChain, config.BridgeName, hairpinMode, false)
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})
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if ipVersion == iptables.IPv4 {
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n.portMapper.SetIptablesChain(natChain, n.getNetworkBridgeName())
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} else {
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n.portMapperV6.SetIptablesChain(natChain, n.getNetworkBridgeName())
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}
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}
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d.Lock()
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err = iptable.EnsureJumpRule("FORWARD", IsolationChain1)
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d.Unlock()
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return err
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}
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type iptRule struct {
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table iptables.Table
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chain string
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preArgs []string
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args []string
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}
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func setupIPTablesInternal(hostIP net.IP, bridgeIface string, addr *net.IPNet, icc, ipmasq, hairpin, enable bool) error {
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var (
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address = addr.String()
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skipDNAT = iptRule{table: iptables.Nat, chain: DockerChain, preArgs: []string{"-t", "nat"}, args: []string{"-i", bridgeIface, "-j", "RETURN"}}
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outRule = iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-i", bridgeIface, "!", "-o", bridgeIface, "-j", "ACCEPT"}}
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natArgs []string
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hpNatArgs []string
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)
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// if hostIP is set use this address as the src-ip during SNAT
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if hostIP != nil {
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hostAddr := hostIP.String()
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natArgs = []string{"-s", address, "!", "-o", bridgeIface, "-j", "SNAT", "--to-source", hostAddr}
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hpNatArgs = []string{"-m", "addrtype", "--src-type", "LOCAL", "-o", bridgeIface, "-j", "SNAT", "--to-source", hostAddr}
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// Else use MASQUERADE which picks the src-ip based on NH from the route table
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} else {
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natArgs = []string{"-s", address, "!", "-o", bridgeIface, "-j", "MASQUERADE"}
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hpNatArgs = []string{"-m", "addrtype", "--src-type", "LOCAL", "-o", bridgeIface, "-j", "MASQUERADE"}
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}
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natRule := iptRule{table: iptables.Nat, chain: "POSTROUTING", preArgs: []string{"-t", "nat"}, args: natArgs}
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hpNatRule := iptRule{table: iptables.Nat, chain: "POSTROUTING", preArgs: []string{"-t", "nat"}, args: hpNatArgs}
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ipVersion := iptables.IPv4
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if addr.IP.To4() == nil {
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ipVersion = iptables.IPv6
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}
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// Set NAT.
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if ipmasq {
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if err := programChainRule(ipVersion, natRule, "NAT", enable); err != nil {
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return err
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}
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}
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if ipmasq && !hairpin {
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if err := programChainRule(ipVersion, skipDNAT, "SKIP DNAT", enable); err != nil {
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return err
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}
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}
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// In hairpin mode, masquerade traffic from localhost
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if hairpin {
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if err := programChainRule(ipVersion, hpNatRule, "MASQ LOCAL HOST", enable); err != nil {
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return err
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}
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}
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// Set Inter Container Communication.
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if err := setIcc(ipVersion, bridgeIface, icc, enable); err != nil {
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return err
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}
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// Set Accept on all non-intercontainer outgoing packets.
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return programChainRule(ipVersion, outRule, "ACCEPT NON_ICC OUTGOING", enable)
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}
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func programChainRule(version iptables.IPVersion, rule iptRule, ruleDescr string, insert bool) error {
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iptable := iptables.GetIptable(version)
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var (
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prefix []string
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operation string
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condition bool
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doesExist = iptable.Exists(rule.table, rule.chain, rule.args...)
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)
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if insert {
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condition = !doesExist
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prefix = []string{"-I", rule.chain}
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operation = "enable"
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} else {
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condition = doesExist
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prefix = []string{"-D", rule.chain}
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operation = "disable"
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}
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if rule.preArgs != nil {
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prefix = append(rule.preArgs, prefix...)
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}
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if condition {
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if err := iptable.RawCombinedOutput(append(prefix, rule.args...)...); err != nil {
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return fmt.Errorf("Unable to %s %s rule: %s", operation, ruleDescr, err.Error())
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}
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}
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return nil
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}
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func setIcc(version iptables.IPVersion, bridgeIface string, iccEnable, insert bool) error {
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iptable := iptables.GetIptable(version)
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var (
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table = iptables.Filter
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chain = "FORWARD"
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args = []string{"-i", bridgeIface, "-o", bridgeIface, "-j"}
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acceptArgs = append(args, "ACCEPT")
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dropArgs = append(args, "DROP")
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)
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if insert {
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if !iccEnable {
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iptable.Raw(append([]string{"-D", chain}, acceptArgs...)...)
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if !iptable.Exists(table, chain, dropArgs...) {
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if err := iptable.RawCombinedOutput(append([]string{"-A", chain}, dropArgs...)...); err != nil {
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return fmt.Errorf("Unable to prevent intercontainer communication: %s", err.Error())
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}
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}
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} else {
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iptable.Raw(append([]string{"-D", chain}, dropArgs...)...)
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if !iptable.Exists(table, chain, acceptArgs...) {
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if err := iptable.RawCombinedOutput(append([]string{"-I", chain}, acceptArgs...)...); err != nil {
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return fmt.Errorf("Unable to allow intercontainer communication: %s", err.Error())
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}
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}
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}
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} else {
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// Remove any ICC rule.
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if !iccEnable {
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if iptable.Exists(table, chain, dropArgs...) {
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iptable.Raw(append([]string{"-D", chain}, dropArgs...)...)
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}
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} else {
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if iptable.Exists(table, chain, acceptArgs...) {
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iptable.Raw(append([]string{"-D", chain}, acceptArgs...)...)
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}
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}
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}
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return nil
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}
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// Control Inter Network Communication. Install[Remove] only if it is [not] present.
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func setINC(version iptables.IPVersion, iface string, enable bool) error {
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iptable := iptables.GetIptable(version)
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var (
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action = iptables.Insert
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actionMsg = "add"
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chains = []string{IsolationChain1, IsolationChain2}
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rules = [][]string{
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{"-i", iface, "!", "-o", iface, "-j", IsolationChain2},
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{"-o", iface, "-j", "DROP"},
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}
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)
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if !enable {
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action = iptables.Delete
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actionMsg = "remove"
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}
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for i, chain := range chains {
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if err := iptable.ProgramRule(iptables.Filter, chain, action, rules[i]); err != nil {
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msg := fmt.Sprintf("unable to %s inter-network communication rule: %v", actionMsg, err)
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if enable {
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if i == 1 {
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// Rollback the rule installed on first chain
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if err2 := iptable.ProgramRule(iptables.Filter, chains[0], iptables.Delete, rules[0]); err2 != nil {
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logrus.Warnf("Failed to rollback iptables rule after failure (%v): %v", err, err2)
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}
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}
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return fmt.Errorf(msg)
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}
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logrus.Warn(msg)
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}
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}
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return nil
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}
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// Obsolete chain from previous docker versions
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const oldIsolationChain = "DOCKER-ISOLATION"
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func removeIPChains(version iptables.IPVersion) {
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ipt := iptables.IPTable{Version: version}
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// Remove obsolete rules from default chains
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ipt.ProgramRule(iptables.Filter, "FORWARD", iptables.Delete, []string{"-j", oldIsolationChain})
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// Remove chains
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for _, chainInfo := range []iptables.ChainInfo{
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{Name: DockerChain, Table: iptables.Nat, IPTable: ipt},
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{Name: DockerChain, Table: iptables.Filter, IPTable: ipt},
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{Name: IsolationChain1, Table: iptables.Filter, IPTable: ipt},
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{Name: IsolationChain2, Table: iptables.Filter, IPTable: ipt},
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{Name: oldIsolationChain, Table: iptables.Filter, IPTable: ipt},
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} {
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if err := chainInfo.Remove(); err != nil {
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logrus.Warnf("Failed to remove existing iptables entries in table %s chain %s : %v", chainInfo.Table, chainInfo.Name, err)
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}
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}
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}
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func setupInternalNetworkRules(bridgeIface string, addr *net.IPNet, icc, insert bool) error {
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var (
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inDropRule = iptRule{table: iptables.Filter, chain: IsolationChain1, args: []string{"-i", bridgeIface, "!", "-d", addr.String(), "-j", "DROP"}}
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outDropRule = iptRule{table: iptables.Filter, chain: IsolationChain1, args: []string{"-o", bridgeIface, "!", "-s", addr.String(), "-j", "DROP"}}
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)
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version := iptables.IPv4
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if addr.IP.To4() == nil {
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version = iptables.IPv6
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}
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if err := programChainRule(version, inDropRule, "DROP INCOMING", insert); err != nil {
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return err
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}
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if err := programChainRule(version, outDropRule, "DROP OUTGOING", insert); err != nil {
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return err
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}
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// Set Inter Container Communication.
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return setIcc(version, bridgeIface, icc, insert)
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}
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func clearEndpointConnections(nlh *netlink.Handle, ep *bridgeEndpoint) {
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var ipv4List []net.IP
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var ipv6List []net.IP
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if ep.addr != nil {
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ipv4List = append(ipv4List, ep.addr.IP)
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}
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if ep.addrv6 != nil {
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ipv6List = append(ipv6List, ep.addrv6.IP)
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}
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iptables.DeleteConntrackEntries(nlh, ipv4List, ipv6List)
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}
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