Create tests for pkg/iptables

Docker-DCO-1.1-Signed-off-by: Ian Bishop <ianbishop@pace7.com> (github: porjo)

iptables/iptables.go

@@ -114,7 +114,7 @@ func RemoveExistingChain(name string, table Table) error {
 }
 
 // Add forwarding rule to 'filter' table and corresponding nat rule to 'nat' table
-func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr string, dest_port int) error {
+func (c *Chain) Forward(action Action, ip net.IP, port int, proto, destAddr string, destPort int) error {
 	daddr := ip.String()
 	if ip.IsUnspecified() {
 		// iptables interprets "0.0.0.0" as "0.0.0.0/32", whereas we
@@ -128,7 +128,7 @@ func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr str
 		"--dport", strconv.Itoa(port),
 		"!", "-i", c.Bridge,
 		"-j", "DNAT",
-		"--to-destination", net.JoinHostPort(dest_addr, strconv.Itoa(dest_port))); err != nil {
+		"--to-destination", net.JoinHostPort(destAddr, strconv.Itoa(destPort))); err != nil {
 		return err
 	} else if len(output) != 0 {
 		return &ChainError{Chain: "FORWARD", Output: output}
@@ -138,14 +138,25 @@ func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr str
 		"!", "-i", c.Bridge,
 		"-o", c.Bridge,
 		"-p", proto,
-		"-d", dest_addr,
+		"-d", destAddr,
-		"--dport", strconv.Itoa(dest_port),
+		"--dport", strconv.Itoa(destPort),
 		"-j", "ACCEPT"); err != nil {
 		return err
 	} else if len(output) != 0 {
 		return &ChainError{Chain: "FORWARD", Output: output}
 	}
 
+	if output, err := Raw("-t", string(Nat), string(action), "POSTROUTING",
+		"-p", proto,
+		"-s", destAddr,
+		"-d", destAddr,
+		"--dport", strconv.Itoa(destPort),
+		"-j", "MASQUERADE"); err != nil {
+		return err
+	} else if len(output) != 0 {
+		return &ChainError{Chain: "FORWARD", Output: output}
+	}
+
 	return nil
 }
 
@@ -156,8 +167,8 @@ func (c *Chain) Link(action Action, ip1, ip2 net.IP, port int, proto string) err
 		"-i", c.Bridge, "-o", c.Bridge,
 		"-p", proto,
 		"-s", ip1.String(),
-		"--dport", strconv.Itoa(port),
 		"-d", ip2.String(),
+		"--dport", strconv.Itoa(port),
 		"-j", "ACCEPT"); err != nil {
 		return err
 	} else if len(output) != 0 {
@@ -167,8 +178,8 @@ func (c *Chain) Link(action Action, ip1, ip2 net.IP, port int, proto string) err
 		"-i", c.Bridge, "-o", c.Bridge,
 		"-p", proto,
 		"-s", ip2.String(),
-		"--dport", strconv.Itoa(port),
 		"-d", ip1.String(),
+		"--sport", strconv.Itoa(port),
 		"-j", "ACCEPT"); err != nil {
 		return err
 	} else if len(output) != 0 {
@@ -206,18 +217,17 @@ func (c *Chain) Output(action Action, args ...string) error {
 }
 
 func (c *Chain) Remove() error {
+	// Ignore errors - This could mean the chains were never set up
 	if c.Table == Nat {
-		// Ignore errors - This could mean the chains were never set up
 		c.Prerouting(Delete, "-m", "addrtype", "--dst-type", "LOCAL")
 		c.Output(Delete, "-m", "addrtype", "--dst-type", "LOCAL", "!", "--dst", "127.0.0.0/8")
 		c.Output(Delete, "-m", "addrtype", "--dst-type", "LOCAL") // Created in versions <= 0.1.6
 
 		c.Prerouting(Delete)
 		c.Output(Delete)
-
-		Raw("-t", string(Nat), "-F", c.Name)
-		Raw("-t", string(Nat), "-X", c.Name)
 	}
+	Raw("-t", string(c.Table), "-F", c.Name)
+	Raw("-t", string(c.Table), "-X", c.Name)
 	return nil
 }
 

iptables/iptables_test.go

@@ -0,0 +1,204 @@
+package iptables
+
+import (
+	"net"
+	"os/exec"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+const chainName = "DOCKERTEST"
+
+var natChain *Chain
+var filterChain *Chain
+
+func TestNewChain(t *testing.T) {
+	var err error
+
+	natChain, err = NewChain(chainName, "lo", Nat)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	filterChain, err = NewChain(chainName, "lo", Filter)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestForward(t *testing.T) {
+	ip := net.ParseIP("192.168.1.1")
+	port := 1234
+	dstAddr := "172.17.0.1"
+	dstPort := 4321
+	proto := "tcp"
+
+	err := natChain.Forward(Insert, ip, port, proto, dstAddr, dstPort)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	dnatRule := []string{natChain.Name,
+		"-t", string(natChain.Table),
+		"!", "-i", filterChain.Bridge,
+		"-d", ip.String(),
+		"-p", proto,
+		"--dport", strconv.Itoa(port),
+		"-j", "DNAT",
+		"--to-destination", dstAddr + ":" + strconv.Itoa(dstPort),
+	}
+
+	if !Exists(dnatRule...) {
+		t.Fatalf("DNAT rule does not exist")
+	}
+
+	filterRule := []string{filterChain.Name,
+		"-t", string(filterChain.Table),
+		"!", "-i", filterChain.Bridge,
+		"-o", filterChain.Bridge,
+		"-d", dstAddr,
+		"-p", proto,
+		"--dport", strconv.Itoa(dstPort),
+		"-j", "ACCEPT",
+	}
+
+	if !Exists(filterRule...) {
+		t.Fatalf("filter rule does not exist")
+	}
+
+	masqRule := []string{"POSTROUTING",
+		"-t", string(natChain.Table),
+		"-d", dstAddr,
+		"-s", dstAddr,
+		"-p", proto,
+		"--dport", strconv.Itoa(dstPort),
+		"-j", "MASQUERADE",
+	}
+
+	if !Exists(masqRule...) {
+		t.Fatalf("MASQUERADE rule does not exist")
+	}
+}
+
+func TestLink(t *testing.T) {
+	var err error
+
+	ip1 := net.ParseIP("192.168.1.1")
+	ip2 := net.ParseIP("192.168.1.2")
+	port := 1234
+	proto := "tcp"
+
+	err = filterChain.Link(Append, ip1, ip2, port, proto)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rule1 := []string{filterChain.Name,
+		"-t", string(filterChain.Table),
+		"-i", filterChain.Bridge,
+		"-o", filterChain.Bridge,
+		"-p", proto,
+		"-s", ip1.String(),
+		"-d", ip2.String(),
+		"--dport", strconv.Itoa(port),
+		"-j", "ACCEPT"}
+
+	if !Exists(rule1...) {
+		t.Fatalf("rule1 does not exist")
+	}
+
+	rule2 := []string{filterChain.Name,
+		"-t", string(filterChain.Table),
+		"-i", filterChain.Bridge,
+		"-o", filterChain.Bridge,
+		"-p", proto,
+		"-s", ip2.String(),
+		"-d", ip1.String(),
+		"--sport", strconv.Itoa(port),
+		"-j", "ACCEPT"}
+
+	if !Exists(rule2...) {
+		t.Fatalf("rule2 does not exist")
+	}
+}
+
+func TestPrerouting(t *testing.T) {
+	args := []string{
+		"-i", "lo",
+		"-d", "192.168.1.1"}
+
+	err := natChain.Prerouting(Insert, args...)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rule := []string{"PREROUTING",
+		"-t", string(Nat),
+		"-j", natChain.Name}
+
+	rule = append(rule, args...)
+
+	if !Exists(rule...) {
+		t.Fatalf("rule does not exist")
+	}
+
+	delRule := append([]string{"-D"}, rule...)
+	if _, err = Raw(delRule...); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestOutput(t *testing.T) {
+	args := []string{
+		"-o", "lo",
+		"-d", "192.168.1.1"}
+
+	err := natChain.Output(Insert, args...)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rule := []string{"OUTPUT",
+		"-t", string(natChain.Table),
+		"-j", natChain.Name}
+
+	rule = append(rule, args...)
+
+	if !Exists(rule...) {
+		t.Fatalf("rule does not exist")
+	}
+
+	delRule := append([]string{"-D"}, rule...)
+	if _, err = Raw(delRule...); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestCleanup(t *testing.T) {
+	var err error
+	var rules []byte
+
+	// Cleanup filter/FORWARD first otherwise output of iptables-save is dirty
+	link := []string{"-t", string(filterChain.Table),
+		string(Delete), "FORWARD",
+		"-o", filterChain.Bridge,
+		"-j", filterChain.Name}
+	if _, err = Raw(link...); err != nil {
+		t.Fatal(err)
+	}
+	filterChain.Remove()
+
+	err = RemoveExistingChain(chainName, Nat)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rules, err = exec.Command("iptables-save").Output()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(string(rules), chainName) {
+		t.Fatalf("Removing chain failed. %s found in iptables-save", chainName)
+	}
+}