Merge pull request #961 from JrCs/fix-iptables-order

Fix bad order of iptables filter rules

Author: Santhosh Manohar

drivers/bridge/setup_ip_tables.go

@@ -140,7 +140,6 @@ func setupIPTablesInternal(bridgeIface string, addr net.Addr, icc, ipmasq, hairp
 		hpNatRule = iptRule{table: iptables.Nat, chain: "POSTROUTING", preArgs: []string{"-t", "nat"}, args: []string{"-m", "addrtype", "--src-type", "LOCAL", "-o", bridgeIface, "-j", "MASQUERADE"}}
 		skipDNAT  = iptRule{table: iptables.Nat, chain: DockerChain, preArgs: []string{"-t", "nat"}, args: []string{"-i", bridgeIface, "-j", "RETURN"}}
 		outRule   = iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-i", bridgeIface, "!", "-o", bridgeIface, "-j", "ACCEPT"}}
-		inRule    = iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-o", bridgeIface, "-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"}}
 	)
 
 	// Set NAT.
@@ -173,11 +172,6 @@ func setupIPTablesInternal(bridgeIface string, addr net.Addr, icc, ipmasq, hairp
 		return err
 	}
 
-	// Set Accept on incoming packets for existing connections.
-	if err := programChainRule(inRule, "ACCEPT INCOMING", enable); err != nil {
-		return err
-	}
-
 	return nil
 }
 

drivers/bridge/setup_ip_tables_test.go

@@ -32,8 +32,8 @@ func TestProgramIPTable(t *testing.T) {
 	}{
 		{iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-d", "127.1.2.3", "-i", "lo", "-o", "lo", "-j", "DROP"}}, "Test Loopback"},
 		{iptRule{table: iptables.Nat, chain: "POSTROUTING", preArgs: []string{"-t", "nat"}, args: []string{"-s", iptablesTestBridgeIP, "!", "-o", DefaultBridgeName, "-j", "MASQUERADE"}}, "NAT Test"},
-		{iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-i", DefaultBridgeName, "!", "-o", DefaultBridgeName, "-j", "ACCEPT"}}, "Test ACCEPT NON_ICC OUTGOING"},
 		{iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-o", DefaultBridgeName, "-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"}}, "Test ACCEPT INCOMING"},
+		{iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-i", DefaultBridgeName, "!", "-o", DefaultBridgeName, "-j", "ACCEPT"}}, "Test ACCEPT NON_ICC OUTGOING"},
 		{iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-i", DefaultBridgeName, "-o", DefaultBridgeName, "-j", "ACCEPT"}}, "Test enable ICC"},
 		{iptRule{table: iptables.Filter, chain: "FORWARD", args: []string{"-i", DefaultBridgeName, "-o", DefaultBridgeName, "-j", "DROP"}}, "Test disable ICC"},
 	}

iptables/iptables.go

@@ -189,6 +189,26 @@ func ProgramChain(c *ChainInfo, bridgeName string, hairpinMode, enable bool) err
 			}
 
 		}
+		establish := []string{
+			"-o", bridgeName,
+			"-m", "conntrack",
+			"--ctstate", "RELATED,ESTABLISHED",
+			"-j", "ACCEPT"}
+		if !Exists(Filter, "FORWARD", establish...) && enable {
+			insert := append([]string{string(Insert), "FORWARD"}, establish...)
+			if output, err := Raw(insert...); err != nil {
+				return err
+			} else if len(output) != 0 {
+				return fmt.Errorf("Could not create establish rule to %s: %s", c.Table, output)
+			}
+		} else if Exists(Filter, "FORWARD", establish...) && !enable {
+			del := append([]string{string(Delete), "FORWARD"}, establish...)
+			if output, err := Raw(del...); err != nil {
+				return err
+			} else if len(output) != 0 {
+				return fmt.Errorf("Could not delete establish rule from %s: %s", c.Table, output)
+			}
+		}
 	}
 	return nil
 }