324 lines
9.5 KiB
Go
324 lines
9.5 KiB
Go
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/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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IsolationChain = "DOCKER-ISOLATION"
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)
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func setupIPChains(config *configuration) (*iptables.ChainInfo, *iptables.ChainInfo, *iptables.ChainInfo, error) {
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// Sanity check.
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if config.EnableIPTables == false {
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return 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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natChain, err := iptables.NewChain(DockerChain, iptables.Nat, hairpinMode)
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if err != nil {
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return nil, nil, nil, fmt.Errorf("failed to create NAT 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 := iptables.RemoveExistingChain(DockerChain, iptables.Nat); err != nil {
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logrus.Warnf("failed on removing iptables NAT chain on cleanup: %v", err)
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}
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}
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}()
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filterChain, err := iptables.NewChain(DockerChain, iptables.Filter, false)
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if err != nil {
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return nil, nil, nil, fmt.Errorf("failed to create FILTER 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 := iptables.RemoveExistingChain(DockerChain, iptables.Filter); err != nil {
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logrus.Warnf("failed on removing iptables FILTER chain on cleanup: %v", err)
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}
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}
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}()
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isolationChain, err := iptables.NewChain(IsolationChain, iptables.Filter, false)
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if err != nil {
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return nil, nil, nil, fmt.Errorf("failed to create FILTER isolation chain: %v", err)
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}
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if err := iptables.AddReturnRule(IsolationChain); err != nil {
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return nil, nil, nil, err
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}
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return natChain, filterChain, isolationChain, nil
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}
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func (n *bridgeNetwork) setupIPTables(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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// Sanity check.
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if driverConfig.EnableIPTables == false {
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return errors.New("Cannot program chains, EnableIPTable is disabled")
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}
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// Pickup this configuration option from driver
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hairpinMode := !driverConfig.EnableUserlandProxy
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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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if config.Internal {
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if err = setupInternalNetworkRules(config.BridgeName, maskedAddrv4, 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, maskedAddrv4, config.EnableICC, false)
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})
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} else {
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if err = setupIPTablesInternal(config.BridgeName, maskedAddrv4, 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.BridgeName, maskedAddrv4, config.EnableICC, config.EnableIPMasquerade, hairpinMode, false)
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})
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natChain, filterChain, _, err := n.getDriverChains()
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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 = iptables.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 = iptables.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 iptables.ProgramChain(filterChain, config.BridgeName, hairpinMode, false)
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})
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n.portMapper.SetIptablesChain(natChain, n.getNetworkBridgeName())
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}
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d.Lock()
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err = iptables.EnsureJumpRule("FORWARD", IsolationChain)
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d.Unlock()
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if err != nil {
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return err
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}
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return nil
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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(bridgeIface string, addr net.Addr, icc, ipmasq, hairpin, enable bool) error {
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var (
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address = addr.String()
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natRule = iptRule{table: iptables.Nat, chain: "POSTROUTING", preArgs: []string{"-t", "nat"}, args: []string{"-s", address, "!", "-o", bridgeIface, "-j", "MASQUERADE"}}
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hpNatRule = iptRule{table: iptables.Nat, chain: "POSTROUTING", preArgs: []string{"-t", "nat"}, args: []string{"-m", "addrtype", "--src-type", "LOCAL", "-o", bridgeIface, "-j", "MASQUERADE"}}
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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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)
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// Set NAT.
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if ipmasq {
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if err := programChainRule(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(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(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(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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if err := programChainRule(outRule, "ACCEPT NON_ICC OUTGOING", enable); err != nil {
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return err
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}
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return nil
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}
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func programChainRule(rule iptRule, ruleDescr string, insert bool) error {
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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 = iptables.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 := iptables.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(bridgeIface string, iccEnable, insert bool) error {
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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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iptables.Raw(append([]string{"-D", chain}, acceptArgs...)...)
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if !iptables.Exists(table, chain, dropArgs...) {
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if err := iptables.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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iptables.Raw(append([]string{"-D", chain}, dropArgs...)...)
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if !iptables.Exists(table, chain, acceptArgs...) {
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if err := iptables.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 iptables.Exists(table, chain, dropArgs...) {
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iptables.Raw(append([]string{"-D", chain}, dropArgs...)...)
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}
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} else {
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if iptables.Exists(table, chain, acceptArgs...) {
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iptables.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/is present.
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func setINC(iface1, iface2 string, enable bool) error {
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var (
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table = iptables.Filter
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chain = IsolationChain
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args = [2][]string{{"-i", iface1, "-o", iface2, "-j", "DROP"}, {"-i", iface2, "-o", iface1, "-j", "DROP"}}
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)
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if enable {
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for i := 0; i < 2; i++ {
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if iptables.Exists(table, chain, args[i]...) {
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continue
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}
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if err := iptables.RawCombinedOutput(append([]string{"-I", chain}, args[i]...)...); err != nil {
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return fmt.Errorf("unable to add inter-network communication rule: %v", err)
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}
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}
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} else {
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for i := 0; i < 2; i++ {
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if !iptables.Exists(table, chain, args[i]...) {
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continue
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}
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if err := iptables.RawCombinedOutput(append([]string{"-D", chain}, args[i]...)...); err != nil {
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return fmt.Errorf("unable to remove inter-network communication rule: %v", err)
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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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func removeIPChains() {
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for _, chainInfo := range []iptables.ChainInfo{
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{Name: DockerChain, Table: iptables.Nat},
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{Name: DockerChain, Table: iptables.Filter},
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{Name: IsolationChain, Table: iptables.Filter},
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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.Addr, icc, insert bool) error {
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var (
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inDropRule = iptRule{table: iptables.Filter, chain: IsolationChain, args: []string{"-i", bridgeIface, "!", "-d", addr.String(), "-j", "DROP"}}
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outDropRule = iptRule{table: iptables.Filter, chain: IsolationChain, args: []string{"-o", bridgeIface, "!", "-s", addr.String(), "-j", "DROP"}}
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)
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if err := programChainRule(inDropRule, "DROP INCOMING", insert); err != nil {
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return err
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}
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if err := programChainRule(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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if err := setIcc(bridgeIface, icc, insert); err != nil {
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return err
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}
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return nil
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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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