Create DOCKER forward chain on driver init
Docker-DCO-1.1-Signed-off-by: Ian Bishop <ianbishop@pace7.com> (github: porjo)
This commit is contained in:
Porjo
Ian Bishop
parent
79e3a90569
commit
7bcd294c4e
1 changed files with 84 additions and 73 deletions
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@ -13,15 +13,17 @@ import (
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)
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type Action string
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type Table string
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const (
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Append Action = "-A"
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Delete Action = "-D"
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Insert Action = "-I"
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Nat Table = "nat"
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Filter Table = "filter"
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)
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var (
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nat = []string{"-t", "nat"}
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supportsXlock = false
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ErrIptablesNotFound = errors.New("Iptables not found")
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)
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@ -29,6 +31,7 @@ var (
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type Chain struct {
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Name string
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Bridge string
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Table Table
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}
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type ChainError struct {
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@ -44,33 +47,73 @@ func init() {
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supportsXlock = exec.Command("iptables", "--wait", "-L", "-n").Run() == nil
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}
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func NewChain(name, bridge string) (*Chain, error) {
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if output, err := Raw("-t", "nat", "-N", name); err != nil {
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return nil, err
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} else if len(output) != 0 {
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return nil, fmt.Errorf("Error creating new iptables chain: %s", output)
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}
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chain := &Chain{
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func NewChain(name, bridge string, table Table) (*Chain, error) {
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c := &Chain{
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Name: name,
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Bridge: bridge,
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Table: table,
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}
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if err := chain.Prerouting(Append, "-m", "addrtype", "--dst-type", "LOCAL"); err != nil {
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if string(c.Table) == "" {
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c.Table = Filter
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}
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// Add chain if it doesn't exist
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if _, err := Raw("-t", string(c.Table), "-n", "-L", c.Name); err != nil {
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if output, err := Raw("-t", string(c.Table), "-N", c.Name); err != nil {
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return nil, err
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} else if len(output) != 0 {
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return nil, fmt.Errorf("Could not create %s/%s chain: %s", c.Table, c.Name, output)
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}
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}
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switch table {
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case Nat:
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preroute := []string{
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"-m", "addrtype",
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"--dst-type", "LOCAL"}
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if !Exists(preroute...) {
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if err := c.Prerouting(Append, preroute...); err != nil {
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return nil, fmt.Errorf("Failed to inject docker in PREROUTING chain: %s", err)
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}
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if err := chain.Output(Append, "-m", "addrtype", "--dst-type", "LOCAL", "!", "--dst", "127.0.0.0/8"); err != nil {
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}
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output := []string{
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"-m", "addrtype",
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"--dst-type", "LOCAL",
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"!", "--dst", "127.0.0.0/8"}
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if !Exists(output...) {
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if err := c.Output(Append, output...); err != nil {
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return nil, fmt.Errorf("Failed to inject docker in OUTPUT chain: %s", err)
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}
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return chain, nil
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}
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func RemoveExistingChain(name string) error {
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chain := &Chain{
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Name: name,
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}
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return chain.Remove()
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case Filter:
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link := []string{"FORWARD",
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"-o", c.Bridge,
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"-j", c.Name}
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if !Exists(link...) {
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insert := append([]string{string(Insert)}, link...)
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if output, err := Raw(insert...); err != nil {
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return nil, err
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} else if len(output) != 0 {
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return nil, fmt.Errorf("Could not create linking rule to %s/%s: %s", c.Table, c.Name, output)
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}
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}
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}
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return c, nil
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}
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func RemoveExistingChain(name string, table Table) error {
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c := &Chain{
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Name: name,
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Table: table,
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}
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if string(c.Table) == "" {
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c.Table = Filter
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}
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return c.Remove()
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}
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// Add forwarding rule to 'filter' table and corresponding nat rule to 'nat' table
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func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr string, dest_port int) error {
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daddr := ip.String()
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if ip.IsUnspecified() {
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@ -79,7 +122,7 @@ func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr str
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// value" by both iptables and ip6tables.
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daddr = "0/0"
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}
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if output, err := Raw("-t", "nat", string(action), c.Name,
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if output, err := Raw("-t", string(Nat), string(action), c.Name,
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"-p", proto,
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"-d", daddr,
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"--dport", strconv.Itoa(port),
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@ -91,13 +134,7 @@ func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr str
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return &ChainError{Chain: "FORWARD", Output: output}
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}
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if action != Delete {
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if err := c.createForwardChain(); err != nil {
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return err
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}
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}
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if output, err := Raw(string(action), c.Name,
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if output, err := Raw("-t", string(Filter), string(action), c.Name,
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"!", "-i", c.Bridge,
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"-o", c.Bridge,
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"-p", proto,
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@ -112,13 +149,10 @@ func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr str
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return nil
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}
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// Add reciprocal ACCEPT rule for two supplied IP addresses.
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// Traffic is allowed from ip1 to ip2 and vice-versa
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func (c *Chain) Link(action Action, ip1, ip2 net.IP, port int, proto string) error {
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if action != Delete {
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if err := c.createForwardChain(); err != nil {
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return err
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}
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}
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if output, err := Raw(string(action), c.Name,
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if output, err := Raw("-t", string(Filter), string(action), c.Name,
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"-i", c.Bridge, "-o", c.Bridge,
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"-p", proto,
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"-s", ip1.String(),
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@ -127,10 +161,9 @@ func (c *Chain) Link(action Action, ip1, ip2 net.IP, port int, proto string) err
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"-j", "ACCEPT"); err != nil {
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return err
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} else if len(output) != 0 {
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return fmt.Errorf("Error toggle iptables forward: %s", output)
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return fmt.Errorf("Error iptables forward: %s", output)
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}
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if output, err := Raw(string(action), c.Name,
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if output, err := Raw("-t", string(Filter), string(action), c.Name,
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"-i", c.Bridge, "-o", c.Bridge,
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"-p", proto,
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"-s", ip2.String(),
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@ -139,14 +172,14 @@ func (c *Chain) Link(action Action, ip1, ip2 net.IP, port int, proto string) err
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"-j", "ACCEPT"); err != nil {
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return err
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} else if len(output) != 0 {
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return fmt.Errorf("Error toggle iptables forward: %s", output)
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return fmt.Errorf("Error iptables forward: %s", output)
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}
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return nil
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}
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// Add linking rule to nat/PREROUTING chain.
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func (c *Chain) Prerouting(action Action, args ...string) error {
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a := append(nat, fmt.Sprint(action), "PREROUTING")
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a := []string{"-t", string(Nat), string(action), "PREROUTING"}
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if len(args) > 0 {
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a = append(a, args...)
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}
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@ -158,8 +191,9 @@ func (c *Chain) Prerouting(action Action, args ...string) error {
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return nil
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}
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// Add linking rule to an OUTPUT chain
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func (c *Chain) Output(action Action, args ...string) error {
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a := append(nat, fmt.Sprint(action), "OUTPUT")
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a := []string{"-t", string(c.Table), string(action), "OUTPUT"}
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if len(args) > 0 {
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a = append(a, args...)
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}
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@ -172,6 +206,7 @@ func (c *Chain) Output(action Action, args ...string) error {
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}
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func (c *Chain) Remove() error {
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if c.Table == Nat {
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// Ignore errors - This could mean the chains were never set up
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c.Prerouting(Delete, "-m", "addrtype", "--dst-type", "LOCAL")
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c.Output(Delete, "-m", "addrtype", "--dst-type", "LOCAL", "!", "--dst", "127.0.0.0/8")
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@ -180,13 +215,13 @@ func (c *Chain) Remove() error {
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c.Prerouting(Delete)
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c.Output(Delete)
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Raw("-t", "nat", "-F", c.Name)
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Raw("-t", "nat", "-X", c.Name)
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Raw("-t", string(Nat), "-F", c.Name)
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Raw("-t", string(Nat), "-X", c.Name)
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}
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return nil
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}
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// Check if an existing rule exists
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// Check if a rule exists
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func Exists(args ...string) bool {
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// iptables -C, --check option was added in v.1.4.11
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// http://ftp.netfilter.org/pub/iptables/changes-iptables-1.4.11.txt
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@ -211,6 +246,7 @@ func Exists(args ...string) bool {
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)
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}
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// Call 'iptables' system command, passing supplied arguments
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func Raw(args ...string) ([]byte, error) {
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path, err := exec.LookPath("iptables")
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if err != nil {
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@ -235,28 +271,3 @@ func Raw(args ...string) ([]byte, error) {
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return output, err
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}
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func (c *Chain) createForwardChain() error {
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// Add chain if doesn't exist
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if _, err := Raw("-n", "-L", c.Name); err != nil {
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output, err := Raw("-N", c.Name)
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if err != nil {
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return err
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} else if len(output) != 0 {
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return fmt.Errorf("Error iptables forward: %s", output)
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}
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}
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// Add linking rule if it doesn't exist
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if !Exists("FORWARD",
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"-o", c.Bridge,
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"-j", c.Name) {
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if output2, err := Raw(string(Insert), "FORWARD",
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"-o", c.Bridge,
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"-j", c.Name); err != nil {
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return err
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} else if len(output2) != 0 {
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return fmt.Errorf("Error iptables forward: %s", output2)
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}
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}
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return nil
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}
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