From b30b7f3422202232ad1c385a7ac0d775151fee2f Mon Sep 17 00:00:00 2001 From: Nayana Bidari Date: Tue, 18 Feb 2020 11:30:42 -0800 Subject: Add nat table support for iptables. Add nat table support for Prerouting hook with Redirect option. Add tests to check redirect of ports. --- test/iptables/iptables_test.go | 12 ++++++++ test/iptables/iptables_util.go | 10 +++++++ test/iptables/nat.go | 64 ++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 84 insertions(+), 2 deletions(-) (limited to 'test') diff --git a/test/iptables/iptables_test.go b/test/iptables/iptables_test.go index 46a7c99b0..7d061acba 100644 --- a/test/iptables/iptables_test.go +++ b/test/iptables/iptables_test.go @@ -196,12 +196,24 @@ func TestNATRedirectUDPPort(t *testing.T) { } } +func TestNATRedirectTCPPort(t *testing.T) { + if err := singleTest(NATRedirectTCPPort{}); err != nil { + t.Fatal(err) + } +} + func TestNATDropUDP(t *testing.T) { if err := singleTest(NATDropUDP{}); err != nil { t.Fatal(err) } } +func TestNATAcceptAll(t *testing.T) { + if err := singleTest(NATAcceptAll{}); err != nil { + t.Fatal(err) + } +} + func TestFilterInputDropTCPDestPort(t *testing.T) { if err := singleTest(FilterInputDropTCPDestPort{}); err != nil { t.Fatal(err) diff --git a/test/iptables/iptables_util.go b/test/iptables/iptables_util.go index 043114c78..5c9199abf 100644 --- a/test/iptables/iptables_util.go +++ b/test/iptables/iptables_util.go @@ -35,6 +35,16 @@ func filterTable(args ...string) error { return nil } +// natTable calls `iptables -t nat` with the given args. +func natTable(args ...string) error { + args = append([]string{"-t", "nat"}, args...) + cmd := exec.Command(iptablesBinary, args...) + if out, err := cmd.CombinedOutput(); err != nil { + return fmt.Errorf("error running iptables with args %v\nerror: %v\noutput: %s", args, err, string(out)) + } + return nil +} + // listenUDP listens on a UDP port and returns the value of net.Conn.Read() for // the first read on that port. func listenUDP(port int, timeout time.Duration) error { diff --git a/test/iptables/nat.go b/test/iptables/nat.go index b5c6f927e..306cbd1b3 100644 --- a/test/iptables/nat.go +++ b/test/iptables/nat.go @@ -25,7 +25,9 @@ const ( func init() { RegisterTestCase(NATRedirectUDPPort{}) + RegisterTestCase(NATRedirectTCPPort{}) RegisterTestCase(NATDropUDP{}) + RegisterTestCase(NATAcceptAll{}) } // NATRedirectUDPPort tests that packets are redirected to different port. @@ -38,13 +40,14 @@ func (NATRedirectUDPPort) Name() string { // ContainerAction implements TestCase.ContainerAction. func (NATRedirectUDPPort) ContainerAction(ip net.IP) error { - if err := filterTable("-t", "nat", "-A", "PREROUTING", "-p", "udp", "-j", "REDIRECT", "--to-ports", fmt.Sprintf("%d", redirectPort)); err != nil { + if err := natTable("-A", "PREROUTING", "-p", "udp", "-j", "REDIRECT", "--to-ports", fmt.Sprintf("%d", redirectPort)); err != nil { return err } if err := listenUDP(redirectPort, sendloopDuration); err != nil { return fmt.Errorf("packets on port %d should be allowed, but encountered an error: %v", redirectPort, err) } + return nil } @@ -53,6 +56,37 @@ func (NATRedirectUDPPort) LocalAction(ip net.IP) error { return sendUDPLoop(ip, acceptPort, sendloopDuration) } +// NATRedirectTCPPort tests that connections are redirected on specified ports. +type NATRedirectTCPPort struct{} + +// Name implements TestCase.Name. +func (NATRedirectTCPPort) Name() string { + return "NATRedirectTCPPort" +} + +// ContainerAction implements TestCase.ContainerAction. +func (NATRedirectTCPPort) ContainerAction(ip net.IP) error { + if err := natTable("-A", "PREROUTING", "-p", "tcp", "-m", "tcp", "--dport", fmt.Sprintf("%d", dropPort), "-j", "REDIRECT", "--to-ports", fmt.Sprintf("%d", redirectPort)); err != nil { + return err + } + + // Listen for TCP packets on redirect port. + if err := listenTCP(redirectPort, sendloopDuration); err != nil { + return fmt.Errorf("connection on port %d should be accepted, but got error %v", redirectPort, err) + } + + return nil +} + +// LocalAction implements TestCase.LocalAction. +func (NATRedirectTCPPort) LocalAction(ip net.IP) error { + if err := connectTCP(ip, dropPort, acceptPort, sendloopDuration); err != nil { + return fmt.Errorf("connection destined to port %d should be accepted, but got error %v", dropPort, err) + } + + return nil +} + // NATDropUDP tests that packets are not received in ports other than redirect port. type NATDropUDP struct{} @@ -63,7 +97,7 @@ func (NATDropUDP) Name() string { // ContainerAction implements TestCase.ContainerAction. func (NATDropUDP) ContainerAction(ip net.IP) error { - if err := filterTable("-t", "nat", "-A", "PREROUTING", "-p", "udp", "-j", "REDIRECT", "--to-ports", fmt.Sprintf("%d", redirectPort)); err != nil { + if err := natTable("-A", "PREROUTING", "-p", "udp", "-j", "REDIRECT", "--to-ports", fmt.Sprintf("%d", redirectPort)); err != nil { return err } @@ -78,3 +112,29 @@ func (NATDropUDP) ContainerAction(ip net.IP) error { func (NATDropUDP) LocalAction(ip net.IP) error { return sendUDPLoop(ip, acceptPort, sendloopDuration) } + +// NATAcceptAll tests that all UDP packets are accepted. +type NATAcceptAll struct{} + +// Name implements TestCase.Name. +func (NATAcceptAll) Name() string { + return "NATAcceptAll" +} + +// ContainerAction implements TestCase.ContainerAction. +func (NATAcceptAll) ContainerAction(ip net.IP) error { + if err := natTable("-A", "PREROUTING", "-p", "udp", "-j", "ACCEPT"); err != nil { + return err + } + + if err := listenUDP(acceptPort, sendloopDuration); err != nil { + return fmt.Errorf("packets on port %d should be allowed, but encountered an error: %v", acceptPort, err) + } + + return nil +} + +// LocalAction implements TestCase.LocalAction. +func (NATAcceptAll) LocalAction(ip net.IP) error { + return sendUDPLoop(ip, acceptPort, sendloopDuration) +} -- cgit v1.2.3