ipsec: support UDP encap/decap for NAT traversal

Change-Id: I65c12617ad49e4d5ef242e53988782f0cefa5684
Signed-off-by: Klement Sekera <ksekera@cisco.com>

1 files changed, 260 insertions, 0 deletions

diff --git a/test/test_ipsec_nat.py b/test/test_ipsec_nat.py
new file mode 100644
index 00000000000..9c22fbb559a
--- /dev/null
+++ b/test/test_ipsec_nat.py
@@ -0,0 +1,260 @@
+#!/usr/bin/env python
+
+import socket
+
+from scapy.layers.l2 import Ether
+from scapy.layers.inet import ICMP, IP, TCP, UDP
+from scapy.layers.ipsec import SecurityAssociation, ESP
+from util import ppp, ppc
+from framework import VppTestCase
+
+
+class IPSecNATTestCase(VppTestCase):
+    """ IPSec/NAT
+
+    TRANSPORT MODE:
+
+     ---   encrypt   ---
+    |pg2| <-------> |VPP|
+     ---   decrypt   ---
+
+    TUNNEL MODE:
+
+
+     public network  |   private network
+     ---   encrypt  ---   plain   ---
+    |pg0| <------- |VPP| <------ |pg1|
+     ---            ---           ---
+
+     ---   decrypt  ---   plain   ---
+    |pg0| -------> |VPP| ------> |pg1|
+     ---            ---           ---
+    """
+
+    remote_pg0_client_addr = '1.1.1.1'
+
+    @classmethod
+    def setUpClass(cls):
+        super(IPSecNATTestCase, cls).setUpClass()
+        cls.create_pg_interfaces(range(2))
+        for i in cls.pg_interfaces:
+            i.configure_ipv4_neighbors()
+            i.admin_up()
+            i.config_ip4()
+            i.resolve_arp()
+
+        cls.tcp_port_in = 6303
+        cls.tcp_port_out = 6303
+        cls.udp_port_in = 6304
+        cls.udp_port_out = 6304
+        cls.icmp_id_in = 6305
+        cls.icmp_id_out = 6305
+        cls.config_esp_tun()
+        cls.logger.info(cls.vapi.ppcli("show ipsec"))
+
+    def create_stream_plain(self, src_mac, dst_mac, src_ip, dst_ip):
+        return [
+            # TCP
+            Ether(src=src_mac, dst=dst_mac) /
+            IP(src=src_ip, dst=dst_ip) /
+            TCP(sport=self.tcp_port_in, dport=20),
+            # UDP
+            Ether(src=src_mac, dst=dst_mac) /
+            IP(src=src_ip, dst=dst_ip) /
+            UDP(sport=self.udp_port_in, dport=20),
+            # ICMP
+            Ether(src=src_mac, dst=dst_mac) /
+            IP(src=src_ip, dst=dst_ip) /
+            ICMP(id=self.icmp_id_in, type='echo-request')
+        ]
+
+    def create_stream_encrypted(self, src_mac, dst_mac, src_ip, dst_ip, sa):
+        return [
+            # TCP
+            Ether(src=src_mac, dst=dst_mac) /
+            sa.encrypt(IP(src=src_ip, dst=dst_ip) /
+                       TCP(dport=self.tcp_port_out, sport=20)),
+            # UDP
+            Ether(src=src_mac, dst=dst_mac) /
+            sa.encrypt(IP(src=src_ip, dst=dst_ip) /
+                       UDP(dport=self.udp_port_out, sport=20)),
+            # ICMP
+            Ether(src=src_mac, dst=dst_mac) /
+            sa.encrypt(IP(src=src_ip, dst=dst_ip) /
+                       ICMP(id=self.icmp_id_out, type='echo-request'))
+        ]
+
+    def check_checksum(self, pkt, layer):
+        """ Check checksum of the packet on given layer """
+        new = pkt.__class__(str(pkt))
+        del new[layer].chksum
+        new = new.__class__(str(new))
+        self.assertEqual(new[layer].chksum, pkt[layer].chksum)
+
+    def check_ip_checksum(self, pkt):
+        return self.check_checksum(pkt, 'IP')
+
+    def check_tcp_checksum(self, pkt):
+        return self.check_checksum(pkt, 'TCP')
+
+    def check_udp_checksum(self, pkt):
+        return self.check_checksum(pkt, 'UDP')
+
+    def check_icmp_checksum(self, pkt):
+        return self.check_checksum(pkt, 'ICMP')
+
+    def verify_capture_plain(self, capture):
+        for packet in capture:
+            try:
+                self.check_ip_checksum(packet)
+                self.assert_equal(packet[IP].src, self.pg0.remote_ip4,
+                                  "decrypted packet source address")
+                self.assert_equal(packet[IP].dst, self.pg1.remote_ip4,
+                                  "decrypted packet destination address")
+                if packet.haslayer(TCP):
+                    self.assertFalse(
+                        packet.haslayer(UDP),
+                        "unexpected UDP header in decrypted packet")
+                    self.assert_equal(packet[TCP].dport, self.tcp_port_in,
+                                      "decrypted packet TCP destination port")
+                    self.check_tcp_checksum(packet)
+                elif packet.haslayer(UDP):
+                    if packet[UDP].payload:
+                        self.assertFalse(
+                            packet[UDP][1].haslayer(UDP),
+                            "unexpected UDP header in decrypted packet")
+                    self.assert_equal(packet[UDP].dport, self.udp_port_in,
+                                      "decrypted packet UDP destination port")
+                else:
+                    self.assertFalse(
+                        packet.haslayer(UDP),
+                        "unexpected UDP header in decrypted packet")
+                    self.assert_equal(packet[ICMP].id, self.icmp_id_in,
+                                      "decrypted packet ICMP ID")
+                    self.check_icmp_checksum(packet)
+            except Exception:
+                self.logger.error(
+                    ppp("Unexpected or invalid plain packet:", packet))
+                raise
+
+    def verify_capture_encrypted(self, capture, sa):
+        for packet in capture:
+            try:
+                self.assertIn(ESP, packet[IP])
+                decrypt_pkt = sa.decrypt(packet[IP])
+                self.assert_equal(decrypt_pkt[IP].src, self.pg1.remote_ip4,
+                                  "encrypted packet source address")
+                self.assert_equal(decrypt_pkt[IP].dst, self.pg0.remote_ip4,
+                                  "encrypted packet destination address")
+                # if decrypt_pkt.haslayer(TCP):
+                #     self.tcp_port_out = decrypt_pkt[TCP].sport
+                # elif decrypt_pkt.haslayer(UDP):
+                #     self.udp_port_out = decrypt_pkt[UDP].sport
+                # else:
+                #     self.icmp_id_out = decrypt_pkt[ICMP].id
+            except Exception:
+                self.logger.error(
+                    ppp("Unexpected or invalid encrypted packet:", packet))
+                raise
+
+    @classmethod
+    def config_esp_tun(cls):
+        spd_id = 1
+        remote_sa_id = 10
+        local_sa_id = 20
+        remote_tun_spi = 1001
+        local_tun_spi = 1000
+        client = socket.inet_pton(socket.AF_INET, cls.remote_pg0_client_addr)
+        cls.vapi.ip_add_del_route(client, 32, cls.pg0.remote_ip4n)
+        cls.vapi.ipsec_sad_add_del_entry(remote_sa_id, remote_tun_spi,
+                                         cls.pg1.remote_ip4n,
+                                         cls.pg0.remote_ip4n,
+                                         integrity_key_length=20,
+                                         crypto_key_length=16,
+                                         protocol=1, udp_encap=1)
+        cls.vapi.ipsec_sad_add_del_entry(local_sa_id, local_tun_spi,
+                                         cls.pg0.remote_ip4n,
+                                         cls.pg1.remote_ip4n,
+                                         integrity_key_length=20,
+                                         crypto_key_length=16,
+                                         protocol=1, udp_encap=1)
+        cls.vapi.ipsec_spd_add_del(spd_id)
+        cls.vapi.ipsec_interface_add_del_spd(spd_id, cls.pg0.sw_if_index)
+        l_startaddr = r_startaddr = socket.inet_pton(socket.AF_INET,
+                                                     "0.0.0.0")
+        l_stopaddr = r_stopaddr = socket.inet_pton(socket.AF_INET,
+                                                   "255.255.255.255")
+        cls.vapi.ipsec_spd_add_del_entry(spd_id, l_startaddr, l_stopaddr,
+                                         r_startaddr, r_stopaddr,
+                                         protocol=socket.IPPROTO_ESP)
+        cls.vapi.ipsec_spd_add_del_entry(spd_id, l_startaddr, l_stopaddr,
+                                         r_startaddr, r_stopaddr,
+                                         protocol=socket.IPPROTO_ESP,
+                                         is_outbound=0)
+        cls.vapi.ipsec_spd_add_del_entry(spd_id, l_startaddr, l_stopaddr,
+                                         r_startaddr, r_stopaddr,
+                                         remote_port_start=4500,
+                                         remote_port_stop=4500,
+                                         protocol=socket.IPPROTO_UDP)
+        cls.vapi.ipsec_spd_add_del_entry(spd_id, l_startaddr, l_stopaddr,
+                                         r_startaddr, r_stopaddr,
+                                         remote_port_start=4500,
+                                         remote_port_stop=4500,
+                                         protocol=socket.IPPROTO_UDP,
+                                         is_outbound=0)
+        l_startaddr = l_stopaddr = cls.pg0.remote_ip4n
+        r_startaddr = r_stopaddr = cls.pg1.remote_ip4n
+        cls.vapi.ipsec_spd_add_del_entry(spd_id, l_startaddr, l_stopaddr,
+                                         r_startaddr, r_stopaddr,
+                                         priority=10, policy=3,
+                                         is_outbound=0, sa_id=local_sa_id)
+        cls.vapi.ipsec_spd_add_del_entry(spd_id, r_startaddr, r_stopaddr,
+                                         l_startaddr, l_stopaddr,
+                                         priority=10, policy=3,
+                                         sa_id=remote_sa_id)
+
+    def test_ipsec_nat_tun(self):
+        """ IPSec/NAT tunnel test case """
+        local_tun_sa = SecurityAssociation(ESP, spi=0x000003e9,
+                                           crypt_algo='AES-CBC',
+                                           crypt_key='JPjyOWBeVEQiMe7h',
+                                           auth_algo='HMAC-SHA1-96',
+                                           auth_key='C91KUR9GYMm5GfkEvNjX',
+                                           tunnel_header=IP(
+                                               src=self.pg1.remote_ip4,
+                                               dst=self.pg0.remote_ip4),
+                                           nat_t_header=UDP(
+                                               sport=4500,
+                                               dport=4500))
+        # in2out - from private network to public
+        pkts = self.create_stream_plain(
+            self.pg1.remote_mac, self.pg1.local_mac,
+            self.pg1.remote_ip4, self.pg0.remote_ip4)
+        self.pg1.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(len(pkts))
+        self.verify_capture_encrypted(capture, local_tun_sa)
+
+        remote_tun_sa = SecurityAssociation(ESP, spi=0x000003e8,
+                                            crypt_algo='AES-CBC',
+                                            crypt_key='JPjyOWBeVEQiMe7h',
+                                            auth_algo='HMAC-SHA1-96',
+                                            auth_key='C91KUR9GYMm5GfkEvNjX',
+                                            tunnel_header=IP(
+                                                src=self.pg0.remote_ip4,
+                                                dst=self.pg1.remote_ip4),
+                                            nat_t_header=UDP(
+                                                sport=4500,
+                                                dport=4500))
+
+        # out2in - from public network to private
+        pkts = self.create_stream_encrypted(
+            self.pg0.remote_mac, self.pg0.local_mac,
+            self.pg0.remote_ip4, self.pg1.remote_ip4, remote_tun_sa)
+        self.logger.info(ppc("Sending packets:", pkts))
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(len(pkts))
+        self.verify_capture_plain(capture)