ipsec: huge anti-replay window support
[vpp.git] / test / template_ipsec.py
index 578c284..c438fbb 100644 (file)
@@ -26,7 +26,6 @@ from os import popen
 
 
 class IPsecIPv4Params:
-
     addr_type = socket.AF_INET
     addr_any = "0.0.0.0"
     addr_bcast = "255.255.255.255"
@@ -52,6 +51,8 @@ class IPsecIPv4Params:
         self.outer_flow_label = 0
         self.inner_flow_label = 0x12345
 
+        self.anti_replay_window_size = 64
+
         self.auth_algo_vpp_id = (
             VppEnum.vl_api_ipsec_integ_alg_t.IPSEC_API_INTEG_ALG_SHA1_96
         )
@@ -74,7 +75,6 @@ class IPsecIPv4Params:
 
 
 class IPsecIPv6Params:
-
     addr_type = socket.AF_INET6
     addr_any = "0::0"
     addr_bcast = "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff"
@@ -100,6 +100,8 @@ class IPsecIPv6Params:
         self.outer_flow_label = 0
         self.inner_flow_label = 0x12345
 
+        self.anti_replay_window_size = 64
+
         self.auth_algo_vpp_id = (
             VppEnum.vl_api_ipsec_integ_alg_t.IPSEC_API_INTEG_ALG_SHA1_96
         )
@@ -122,7 +124,7 @@ class IPsecIPv6Params:
 
 
 def mk_scapy_crypt_key(p):
-    if p.crypt_algo in ("AES-GCM", "AES-CTR"):
+    if p.crypt_algo in ("AES-GCM", "AES-CTR", "AES-NULL-GMAC"):
         return p.crypt_key + struct.pack("!I", p.salt)
     else:
         return p.crypt_key
@@ -138,7 +140,7 @@ def config_tun_params(p, encryption_type, tun_if):
     crypt_key = mk_scapy_crypt_key(p)
     p.scapy_tun_sa = SecurityAssociation(
         encryption_type,
-        spi=p.vpp_tun_spi,
+        spi=p.scapy_tun_spi,
         crypt_algo=p.crypt_algo,
         crypt_key=crypt_key,
         auth_algo=p.auth_algo,
@@ -149,7 +151,7 @@ def config_tun_params(p, encryption_type, tun_if):
     )
     p.vpp_tun_sa = SecurityAssociation(
         encryption_type,
-        spi=p.scapy_tun_spi,
+        spi=p.vpp_tun_spi,
         crypt_algo=p.crypt_algo,
         crypt_key=crypt_key,
         auth_algo=p.auth_algo,
@@ -167,7 +169,7 @@ def config_tra_params(p, encryption_type):
     crypt_key = mk_scapy_crypt_key(p)
     p.scapy_tra_sa = SecurityAssociation(
         encryption_type,
-        spi=p.vpp_tra_spi,
+        spi=p.scapy_tra_spi,
         crypt_algo=p.crypt_algo,
         crypt_key=crypt_key,
         auth_algo=p.auth_algo,
@@ -177,7 +179,7 @@ def config_tra_params(p, encryption_type):
     )
     p.vpp_tra_sa = SecurityAssociation(
         encryption_type,
-        spi=p.scapy_tra_spi,
+        spi=p.vpp_tra_spi,
         crypt_algo=p.crypt_algo,
         crypt_key=crypt_key,
         auth_algo=p.auth_algo,
@@ -330,27 +332,25 @@ class IpsecTra4(object):
     """verify methods for Transport v4"""
 
     def get_replay_counts(self, p):
-        replay_node_name = "/err/%s/SA replayed packet" % self.tra4_decrypt_node_name[0]
+        replay_node_name = "/err/%s/replay" % self.tra4_decrypt_node_name[0]
         count = self.statistics.get_err_counter(replay_node_name)
 
         if p.async_mode:
             replay_post_node_name = (
-                "/err/%s/SA replayed packet" % self.tra4_decrypt_node_name[p.async_mode]
+                "/err/%s/replay" % self.tra4_decrypt_node_name[p.async_mode]
             )
             count += self.statistics.get_err_counter(replay_post_node_name)
 
         return count
 
     def get_hash_failed_counts(self, p):
-        if ESP == self.encryption_type and p.crypt_algo == "AES-GCM":
+        if ESP == self.encryption_type and p.crypt_algo in ("AES-GCM", "AES-NULL-GMAC"):
             hash_failed_node_name = (
-                "/err/%s/ESP decryption failed"
-                % self.tra4_decrypt_node_name[p.async_mode]
+                "/err/%s/decryption_failed" % self.tra4_decrypt_node_name[p.async_mode]
             )
         else:
             hash_failed_node_name = (
-                "/err/%s/Integrity check failed"
-                % self.tra4_decrypt_node_name[p.async_mode]
+                "/err/%s/integ_error" % self.tra4_decrypt_node_name[p.async_mode]
             )
         count = self.statistics.get_err_counter(hash_failed_node_name)
 
@@ -365,10 +365,7 @@ class IpsecTra4(object):
         esn_on = p.vpp_tra_sa.esn_en
         ar_on = p.flags & saf.IPSEC_API_SAD_FLAG_USE_ANTI_REPLAY
 
-        seq_cycle_node_name = (
-            "/err/%s/sequence number cycled (packet dropped)"
-            % self.tra4_encrypt_node_name
-        )
+        seq_cycle_node_name = "/err/%s/seq_cycled" % self.tra4_encrypt_node_name
         replay_count = self.get_replay_counts(p)
         hash_failed_count = self.get_hash_failed_counts(p)
         seq_cycle_count = self.statistics.get_err_counter(seq_cycle_node_name)
@@ -437,6 +434,34 @@ class IpsecTra4(object):
         ]
         recv_pkts = self.send_and_expect(self.tra_if, pkts, self.tra_if)
 
+        # a replayed packet, then an out of window, then a legit
+        # tests that a early failure on the batch doesn't affect subsequent packets.
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=203,
+                )
+            ),
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=81,
+                )
+            ),
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=204,
+                )
+            ),
+        ]
+        n_rx = 1 if ar_on else 3
+        recv_pkts = self.send_and_expect(self.tra_if, pkts, self.tra_if, n_rx=n_rx)
+
         # move the window over half way to a wrap
         pkts = [
             (
@@ -604,20 +629,34 @@ class IpsecTra4(object):
     def verify_tra_anti_replay(self):
         p = self.params[socket.AF_INET]
         esn_en = p.vpp_tra_sa.esn_en
+        anti_replay_window_size = p.anti_replay_window_size
 
-        seq_cycle_node_name = (
-            "/err/%s/sequence number cycled (packet dropped)"
-            % self.tra4_encrypt_node_name
-        )
+        seq_cycle_node_name = "/err/%s/seq_cycled" % self.tra4_encrypt_node_name
         replay_count = self.get_replay_counts(p)
+        initial_sa_node_replay_diff = replay_count - p.tra_sa_in.get_err("replay")
         hash_failed_count = self.get_hash_failed_counts(p)
         seq_cycle_count = self.statistics.get_err_counter(seq_cycle_node_name)
+        initial_sa_node_cycled_diff = seq_cycle_count - p.tra_sa_in.get_err(
+            "seq_cycled"
+        )
+        hash_err = "integ_error"
 
         if ESP == self.encryption_type:
-            undersize_node_name = (
-                "/err/%s/undersized packet" % self.tra4_decrypt_node_name[0]
-            )
+            undersize_node_name = "/err/%s/runt" % self.tra4_decrypt_node_name[0]
             undersize_count = self.statistics.get_err_counter(undersize_node_name)
+            initial_sa_node_undersize_diff = undersize_count - p.tra_sa_in.get_err(
+                "runt"
+            )
+            # For AES-GCM an error in the hash is reported as a decryption failure
+            if p.crypt_algo in ("AES-GCM", "AES-NULL-GMAC"):
+                hash_err = "decryption_failed"
+        # In async mode, we don't report errors in the hash.
+        if p.async_mode:
+            hash_err = ""
+        else:
+            initial_sa_node_hash_diff = hash_failed_count - p.tra_sa_in.get_err(
+                hash_err
+            )
 
         #
         # send packets with seq numbers 1->34
@@ -643,6 +682,8 @@ class IpsecTra4(object):
         self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
         replay_count += len(pkts)
         self.assertEqual(self.get_replay_counts(p), replay_count)
+        err = p.tra_sa_in.get_err("replay") + initial_sa_node_replay_diff
+        self.assertEqual(err, replay_count)
 
         #
         # now send a batch of packets all with the same sequence number
@@ -659,25 +700,31 @@ class IpsecTra4(object):
         recv_pkts = self.send_and_expect(self.tra_if, pkts * 8, self.tra_if, n_rx=1)
         replay_count += 7
         self.assertEqual(self.get_replay_counts(p), replay_count)
+        err = p.tra_sa_in.get_err("replay") + initial_sa_node_replay_diff
+        self.assertEqual(err, replay_count)
 
         #
-        # now move the window over to 257 (more than one byte) and into Case A
+        # now move the window over to anti_replay_window_size + 100 and into Case A
         #
         self.vapi.cli("clear error")
         pkt = Ether(
             src=self.tra_if.remote_mac, dst=self.tra_if.local_mac
         ) / p.scapy_tra_sa.encrypt(
             IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
-            seq_num=257,
+            seq_num=anti_replay_window_size + 100,
         )
         recv_pkts = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
 
+        self.logger.info(self.vapi.ppcli("show ipsec sa 1"))
+
         # replayed packets are dropped
         self.send_and_assert_no_replies(self.tra_if, pkt * 3, timeout=0.2)
         replay_count += 3
         self.assertEqual(self.get_replay_counts(p), replay_count)
+        err = p.tra_sa_in.get_err("replay") + initial_sa_node_replay_diff
+        self.assertEqual(err, replay_count)
 
-        # the window size is 64 packets
+        # the window size is anti_replay_window_size packets
         # in window are still accepted
         pkt = Ether(
             src=self.tra_if.remote_mac, dst=self.tra_if.local_mac
@@ -685,12 +732,11 @@ class IpsecTra4(object):
             IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
             seq_num=200,
         )
-        recv_pkts = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
 
         # a packet that does not decrypt does not move the window forward
         bogus_sa = SecurityAssociation(
             self.encryption_type,
-            p.vpp_tra_spi,
+            p.scapy_tra_spi,
             crypt_algo=p.crypt_algo,
             crypt_key=mk_scapy_crypt_key(p)[::-1],
             auth_algo=p.auth_algo,
@@ -700,27 +746,32 @@ class IpsecTra4(object):
             src=self.tra_if.remote_mac, dst=self.tra_if.local_mac
         ) / bogus_sa.encrypt(
             IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
-            seq_num=350,
+            seq_num=anti_replay_window_size + 200,
         )
         self.send_and_assert_no_replies(self.tra_if, pkt * 17, timeout=0.2)
 
         hash_failed_count += 17
         self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+        if hash_err != "":
+            err = p.tra_sa_in.get_err(hash_err) + initial_sa_node_hash_diff
+            self.assertEqual(err, hash_failed_count)
 
         # a malformed 'runt' packet
         #  created by a mis-constructed SA
         if ESP == self.encryption_type and p.crypt_algo != "NULL":
-            bogus_sa = SecurityAssociation(self.encryption_type, p.vpp_tra_spi)
+            bogus_sa = SecurityAssociation(self.encryption_type, p.scapy_tra_spi)
             pkt = Ether(
                 src=self.tra_if.remote_mac, dst=self.tra_if.local_mac
             ) / bogus_sa.encrypt(
                 IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
-                seq_num=350,
+                seq_num=anti_replay_window_size + 200,
             )
             self.send_and_assert_no_replies(self.tra_if, pkt * 17, timeout=0.2)
 
             undersize_count += 17
             self.assert_error_counter_equal(undersize_node_name, undersize_count)
+            err = p.tra_sa_in.get_err("runt") + initial_sa_node_undersize_diff
+            self.assertEqual(err, undersize_count)
 
         # which we can determine since this packet is still in the window
         pkt = Ether(
@@ -749,17 +800,22 @@ class IpsecTra4(object):
             # wrap. but since it isn't then the verify will fail.
             hash_failed_count += 17
             self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+            if hash_err != "":
+                err = p.tra_sa_in.get_err(hash_err) + initial_sa_node_hash_diff
+                self.assertEqual(err, hash_failed_count)
 
         else:
             replay_count += 17
             self.assertEqual(self.get_replay_counts(p), replay_count)
+            err = p.tra_sa_in.get_err("replay") + initial_sa_node_replay_diff
+            self.assertEqual(err, replay_count)
 
-        # valid packet moves the window over to 258
+        # valid packet moves the window over to anti_replay_window_size + 258
         pkt = Ether(
             src=self.tra_if.remote_mac, dst=self.tra_if.local_mac
         ) / p.scapy_tra_sa.encrypt(
             IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
-            seq_num=258,
+            seq_num=anti_replay_window_size + 258,
         )
         rx = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
         decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
@@ -770,7 +826,7 @@ class IpsecTra4(object):
         # causes the TX seq number to wrap; unless we're using extened sequence
         # numbers.
         #
-        self.vapi.cli("test ipsec sa %d seq 0xffffffff" % p.scapy_tra_sa_id)
+        self.vapi.cli("test ipsec sa %d seq 0xffffffff" % p.vpp_tra_sa_id)
         self.logger.info(self.vapi.ppcli("show ipsec sa 0"))
         self.logger.info(self.vapi.ppcli("show ipsec sa 1"))
 
@@ -813,7 +869,7 @@ class IpsecTra4(object):
             decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
 
             #
-            # A packet that has seq num between (2^32-64) and 5 is within
+            # A packet that has seq num between (2^32-anti_replay_window_size)+4 and 5 is within
             # the window
             #
             p.scapy_tra_sa.seq_num = 0xFFFFFFFD
@@ -843,17 +899,20 @@ class IpsecTra4(object):
 
             hash_failed_count += 1
             self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+            if hash_err != "":
+                err = p.tra_sa_in.get_err(hash_err) + initial_sa_node_hash_diff
+                self.assertEqual(err, hash_failed_count)
 
             #
             # but if we move the window forward to case B, then we can wrap
             # again
             #
-            p.scapy_tra_sa.seq_num = 0x100000555
+            p.scapy_tra_sa.seq_num = 0x100000000 + anti_replay_window_size + 0x555
             pkt = Ether(
                 src=self.tra_if.remote_mac, dst=self.tra_if.local_mac
             ) / p.scapy_tra_sa.encrypt(
                 IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
-                seq_num=0x100000555,
+                seq_num=p.scapy_tra_sa.seq_num,
             )
             rx = self.send_and_expect(self.tra_if, [pkt], self.tra_if)
             decrypted = p.vpp_tra_sa.decrypt(rx[0][IP])
@@ -876,6 +935,8 @@ class IpsecTra4(object):
             self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
             seq_cycle_count += len(pkts)
             self.assert_error_counter_equal(seq_cycle_node_name, seq_cycle_count)
+            err = p.tra_sa_out.get_err("seq_cycled") + initial_sa_node_cycled_diff
+            self.assertEqual(err, seq_cycle_count)
 
         # move the security-associations seq number on to the last we used
         self.vapi.cli("test ipsec sa %d seq 0x15f" % p.scapy_tra_sa_id)
@@ -906,7 +967,7 @@ class IpsecTra4(object):
         ]
         self.send_and_expect(self.tra_if, pkts, self.tra_if)
 
-        self.assertEqual(p.tra_sa_out.get_lost(), 0)
+        self.assertEqual(p.tra_sa_in.get_err("lost"), 0)
 
         # skip a sequence number
         pkts = [
@@ -921,7 +982,7 @@ class IpsecTra4(object):
         ]
         self.send_and_expect(self.tra_if, pkts, self.tra_if)
 
-        self.assertEqual(p.tra_sa_out.get_lost(), 0)
+        self.assertEqual(p.tra_sa_in.get_err("lost"), 0)
 
         # the lost packet are counted untill we get up past the first
         # sizeof(replay_window) packets
@@ -937,9 +998,780 @@ class IpsecTra4(object):
         ]
         self.send_and_expect(self.tra_if, pkts, self.tra_if)
 
-        self.assertEqual(p.tra_sa_out.get_lost(), 1)
+        self.assertEqual(p.tra_sa_in.get_err("lost"), 1)
+
+        # lost of holes in the sequence
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(100, 200, 2)
+        ]
+        self.send_and_expect(self.tra_if, pkts, self.tra_if, n_rx=50)
+
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(200, 300)
+        ]
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        self.assertEqual(p.tra_sa_in.get_err("lost"), 51)
+
+        # a big hole in the seq number space
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(400, 500)
+        ]
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        self.assertEqual(p.tra_sa_in.get_err("lost"), 151)
+
+    def verify_tra_basic4(self, count=1, payload_size=54):
+        """ipsec v4 transport basic test"""
+        self.vapi.cli("clear errors")
+        self.vapi.cli("clear ipsec sa")
+        try:
+            p = self.params[socket.AF_INET]
+            send_pkts = self.gen_encrypt_pkts(
+                p,
+                p.scapy_tra_sa,
+                self.tra_if,
+                src=self.tra_if.remote_ip4,
+                dst=self.tra_if.local_ip4,
+                count=count,
+                payload_size=payload_size,
+            )
+            recv_pkts = self.send_and_expect(self.tra_if, send_pkts, self.tra_if)
+            for rx in recv_pkts:
+                self.assertEqual(len(rx) - len(Ether()), rx[IP].len)
+                self.assert_packet_checksums_valid(rx)
+                try:
+                    decrypted = p.vpp_tra_sa.decrypt(rx[IP])
+                    self.assert_packet_checksums_valid(decrypted)
+                except:
+                    self.logger.debug(ppp("Unexpected packet:", rx))
+                    raise
+        finally:
+            self.logger.info(self.vapi.ppcli("show error"))
+            self.logger.info(self.vapi.ppcli("show ipsec all"))
+
+        pkts = p.tra_sa_in.get_stats()["packets"]
+        self.assertEqual(
+            pkts, count, "incorrect SA in counts: expected %d != %d" % (count, pkts)
+        )
+        pkts = p.tra_sa_out.get_stats()["packets"]
+        self.assertEqual(
+            pkts, count, "incorrect SA out counts: expected %d != %d" % (count, pkts)
+        )
+        self.assertEqual(p.tra_sa_out.get_err("lost"), 0)
+        self.assertEqual(p.tra_sa_in.get_err("lost"), 0)
+
+        self.assert_packet_counter_equal(self.tra4_encrypt_node_name, count)
+        self.assert_packet_counter_equal(self.tra4_decrypt_node_name[0], count)
+
+    def _verify_tra_anti_replay_algorithm_esn(self):
+        def seq_num(seqh, seql):
+            return (seqh << 32) | (seql & 0xFFFF_FFFF)
+
+        p = self.params[socket.AF_INET]
+        anti_replay_window_size = p.anti_replay_window_size
+
+        seq_cycle_node_name = "/err/%s/seq_cycled" % self.tra4_encrypt_node_name
+        replay_count = self.get_replay_counts(p)
+        hash_failed_count = self.get_hash_failed_counts(p)
+        seq_cycle_count = self.statistics.get_err_counter(seq_cycle_node_name)
+
+        if ESP == self.encryption_type:
+            undersize_node_name = "/err/%s/runt" % self.tra4_decrypt_node_name[0]
+            undersize_count = self.statistics.get_err_counter(undersize_node_name)
+
+        # reset the TX SA to avoid conflict with left configuration
+        self.vapi.cli(f"test ipsec sa {p.vpp_tra_sa_id} seq 0x0")
+
+        """
+        RFC 4303 Appendix A2. Case A
+
+        |: new Th marker
+        a-i: possible seq num received
+        +: Bl, Tl, Bl', Tl'
+        [BT]l(sign) = [BT]l (sign) 2^32 mod 2^32 (Th inc/dec-remented by 1)
+
+                Th - 1               Th                Th + 1
+        --|--a--+---b---+-c--|--d--+---e---+-f--|--g--+---h---+--i-|--
+                =========          =========          =========
+                Bl-     Tl-        Bl      Tl         Bl+     Tl+
+
+        Case A implies Tl >= W - 1
+        """
+
+        Th = 1
+        Tl = anti_replay_window_size + 40
+        Bl = Tl - anti_replay_window_size + 1
+
+        # move VPP's RX AR window to Case A
+        self.vapi.cli(f"test ipsec sa {p.scapy_tra_sa_id} seq {seq_num(Th, Tl):#x}")
+        p.scapy_tra_sa.seq_num = seq_num(Th, Tl)
+
+        """
+        case a: Seql < Bl
+            - pre-crypto check: algorithm predicts that the packet wrap the window
+                -> Seqh = Th + 1
+            - integrity check: should fail
+            - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th - 1, Bl - 20), seq_num(Th - 1, Bl - 5))
+        ]
+
+        # out-of-window packets fail integrity check
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+        hash_failed_count += len(pkts)
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case b: Bl <= Seql <= Tl
+                - pre-crypto check: algorithm predicts that the packet is in the window
+                    -> Seqh = Th
+                    -> check for a replayed packet with Seql
+                - integrity check: should fail
+                - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, Tl - 10), seq_num(Th, Tl - 5))
+        ]
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        p.scapy_tra_sa.seq_num = seq_num(Th - 1, Tl)
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th - 1, Tl - 35), seq_num(Th - 1, Tl - 5))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+
+        # some packets are rejected by the pre-crypto check
+        replay_count += 5
+        self.assertEqual(self.get_replay_counts(p), replay_count)
+
+        # out-of-window packets fail integrity check
+        hash_failed_count += len(pkts) - 5
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case c: Seql > Tl
+                - pre-crypto check: algorithm predicts that the packet does not wrap the window
+                    -> Seqh = Th
+                - integrity check: should fail
+                - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th - 1, Tl + 5), seq_num(Th - 1, Tl + 20))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+
+        # out-of-window packets fail integrity check
+        hash_failed_count += len(pkts)
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case d: Seql < Bl
+                - pre-crypto check: algorithm predicts that the packet wrap the window
+                    -> Seqh = Th + 1
+                - integrity check: should fail
+                - post-crypto check: ...
+        """
+        p.scapy_tra_sa.seq_num = seq_num(Th, Tl)
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, Bl - 20), seq_num(Th, Bl - 5))
+        ]
+
+        # out-of-window packets fail integrity check
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+        hash_failed_count += len(pkts)
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case e: Bl <= Seql <= Tl
+                - pre-crypto check: algorithm predicts that the packet is in the window
+                    -> Seqh = Th
+                    -> check for a replayed packet with Seql
+                - integrity check: should pass
+                - post-crypto check: should pass
+                    -> Seql is marked in the AR window
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, Bl + 10), seq_num(Th, Bl + 30))
+        ]
+
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        """
+            case f: Seql > Tl
+                - pre-crypto check: algorithm predicts that the packet does not wrap the window
+                    -> Seqh = Th
+                - integrity check: should pass
+                - post-crypto check: should pass
+                    -> AR window shift (the window stays Case A)
+                    -> Seql is marked in the AR window
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, Tl + 50), seq_num(Th, Tl + 60))
+        ]
+
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        """
+            case g: Seql < Bl
+                - pre-crypto check: algorithm predicts that the packet wrap the window
+                    -> Seqh = Th + 1
+                - integrity check: should pass
+                - post-crypto check: should pass
+                    -> AR window shift (may set the window in Case B)
+                    -> Seql is marked in the AR window
+        """
+        p.scapy_tra_sa.seq_num = seq_num(Th + 1, Tl)
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            # set the window in Case B (the minimum window size is 64
+            # so we are sure to overlap)
+            for seq in range(seq_num(Th + 1, 10), seq_num(Th + 1, 20))
+        ]
+
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        # reset the VPP's RX AR window to Case A
+        Th = 1
+        Tl = 2 * anti_replay_window_size + 40
+        Bl = Tl - anti_replay_window_size + 1
+
+        self.vapi.cli(f"test ipsec sa {p.scapy_tra_sa_id} seq {seq_num(Th, Tl):#x}")
+
+        p.scapy_tra_sa.seq_num = seq_num(Th + 1, Tl)
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            # the AR will stay in Case A
+            for seq in range(
+                seq_num(Th + 1, anti_replay_window_size + 10),
+                seq_num(Th + 1, anti_replay_window_size + 20),
+            )
+        ]
+
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        """
+            case h: Bl <= Seql <= Tl
+                - pre-crypto check: algorithm predicts that the packet is in the window
+                    -> Seqh = Th
+                    -> check for a replayed packet with Seql
+                - integrity check: the wrap is not detected, should fail
+                - post-crypto check: ...
+        """
+        Th += 1
+        Tl = anti_replay_window_size + 20
+        Bl = Tl - anti_replay_window_size + 1
+
+        p.scapy_tra_sa.seq_num = seq_num(Th + 1, Tl)
+
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th + 1, Tl - 20), seq_num(Th + 1, Tl - 5))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+
+        # some packets are rejected by the pre-crypto check
+        replay_count += 5
+        self.assertEqual(self.get_replay_counts(p), replay_count)
+
+        # out-of-window packets fail integrity check
+        hash_failed_count += len(pkts) - 5
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case i: Seql > Tl
+                - pre-crypto check: algorithm predicts that the packet does not wrap the window
+                    -> Seqh = Th
+                - integrity check: the wrap is not detected, shoud fail
+                - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th + 1, Tl + 5), seq_num(Th + 1, Tl + 15))
+        ]
+
+        # out-of-window packets fail integrity check
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+        hash_failed_count += len(pkts)
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            RFC 4303 Appendix A2. Case B
+
+                        Th - 1               Th                Th + 1
+            ----|-a-+-----b----+--c--|-d-+----e-----+--f--|-g-+--h---
+            =========          ===========          ===========
+                    Tl-        Bl       Tl          Bl+       Tl+
+
+            Case B implies Tl < W - 1
+        """
+
+        # reset the VPP's RX AR window to Case B
+        Th = 2
+        Tl = 30  # minimum window size of 64, we are sure to overlap
+        Bl = (Tl - anti_replay_window_size + 1) % (1 << 32)
+
+        self.vapi.cli(f"test ipsec sa {p.scapy_tra_sa_id} seq {seq_num(Th, Tl):#x}")
+        p.scapy_tra_sa.seq_num = seq_num(Th, Tl)
+
+        """
+            case a: Seql <= Tl < Bl
+                - pre-crypto check: algorithm predicts that the packet is in the window
+                    -> Seqh = Th
+                    -> check for replayed packet
+                - integrity check: should fail
+                - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, 5), seq_num(Th, 10))
+        ]
+
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        p.scapy_tra_sa.seq_num = seq_num(Th - 1, Tl)
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th - 1, 0), seq_num(Th - 1, 15))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+
+        # some packets are rejected by the pre-crypto check
+        replay_count += 5
+        self.assertEqual(self.get_replay_counts(p), replay_count)
+
+        # out-of-window packets fail integrity check
+        hash_failed_count += len(pkts) - 5
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case b: Tl < Seql < Bl
+                - pre-crypto check: algorithm predicts that the packet will shift the window
+                    -> Seqh = Th
+                - integrity check: should fail
+                - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th - 1, Tl + 10), seq_num(Th - 1, Tl + 20))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+
+        # out-of-window packets fail integrity check
+        hash_failed_count += len(pkts)
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case c: Tl < Bl <= Seql
+                - pre-crypto check: algorithm predicts that the packet is in the window
+                    -> Seqh = Th - 1
+                    -> check for a replayed packet with Seql
+                - integrity check: should pass
+                - post-crypto check: should pass
+                    -> Seql is marked in the AR window
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th - 1, Bl + 10), seq_num(Th - 1, Bl + 20))
+        ]
+
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        """
+            case d: Seql <= Tl < Bl
+                - pre-crypto check: algorithm predicts that the packet is the window
+                    -> Seqh = Th
+                    -> check for replayed packet
+                - integrity check: should pass
+                - post-crypto check: should pass
+                    -> Seql is marked in the AR window
+        """
+        p.scapy_tra_sa.seq_num = seq_num(Th, Tl)
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, 15), seq_num(Th, 25))
+        ]
+
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        """
+            case e: Tl < Seql < Bl
+                - pre-crypto check: algorithm predicts that the packet is in the window
+                    -> Seqh = Th
+                    -> check for a replayed packet with Seql
+                - integrity check: should pass
+                - post-crypto check: should pass
+                    -> AR window shift (may set the window in Case A)
+                    -> Seql is marked in the AR window
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, Tl + 5), seq_num(Th, Tl + 15))
+        ]
+
+        # the window stays in Case B
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(
+                seq_num(Th, Tl + anti_replay_window_size + 5),
+                seq_num(Th, Tl + anti_replay_window_size + 15),
+            )
+        ]
+
+        # the window moves to Case A
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        # reset the VPP's RX AR window to Case B
+        Th = 2
+        Tl = 30  # minimum window size of 64, we are sure to overlap
+        Bl = (Tl - anti_replay_window_size + 1) % (1 << 32)
+
+        self.vapi.cli(f"test ipsec sa {p.scapy_tra_sa_id} seq {seq_num(Th, Tl):#x}")
+        p.scapy_tra_sa.seq_num = seq_num(Th, Tl)
+
+        """
+            case f: Tl < Bl <= Seql
+                - pre-crypto check: algorithm predicts that the packet is in the previous window
+                    -> Seqh = Th - 1
+                    -> check for a replayed packet with Seql
+                - integrity check: should fail
+                - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, Bl + 10), seq_num(Th, Bl + 20))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+
+        # out-of-window packets fail integrity check
+        hash_failed_count += len(pkts)
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case g: Seql <= Tl < Bl
+                - pre-crypto check: algorithm predicts that the packet is the window
+                    -> Seqh = Th
+                    -> check for replayed packet
+                - integrity check: should fail
+                - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th, 10), seq_num(Th, 15))
+        ]
+
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        p.scapy_tra_sa.seq_num = seq_num(Th + 1, Tl)
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th + 1, 0), seq_num(Th + 1, 15))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+
+        # some packets are rejected by the pre-crypto check
+        replay_count += 5
+        self.assertEqual(self.get_replay_counts(p), replay_count)
+
+        # out-of-window packets fail integrity check
+        hash_failed_count += len(pkts) - 5
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+        """
+            case h: Tl < Seql < Bl
+                - pre-crypto check: algorithm predicts that the packet will shift the window
+                    -> Seqh = Th
+                - integrity check: should fail
+                - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Th + 1, Tl + 10), seq_num(Th + 1, Tl + 20))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+
+        # out-of-window packets fail integrity check
+        hash_failed_count += len(pkts)
+        self.assertEqual(self.get_hash_failed_counts(p), hash_failed_count)
+
+    def _verify_tra_anti_replay_algorithm_no_esn(self):
+        def seq_num(seql):
+            return seql & 0xFFFF_FFFF
+
+        p = self.params[socket.AF_INET]
+        anti_replay_window_size = p.anti_replay_window_size
+
+        seq_cycle_node_name = "/err/%s/seq_cycled" % self.tra4_encrypt_node_name
+        replay_count = self.get_replay_counts(p)
+        hash_failed_count = self.get_hash_failed_counts(p)
+        seq_cycle_count = self.statistics.get_err_counter(seq_cycle_node_name)
+
+        if ESP == self.encryption_type:
+            undersize_node_name = "/err/%s/runt" % self.tra4_decrypt_node_name[0]
+            undersize_count = self.statistics.get_err_counter(undersize_node_name)
+
+        # reset the TX SA to avoid conflict with left configuration
+        self.vapi.cli(f"test ipsec sa {p.vpp_tra_sa_id} seq 0x0")
+
+        """
+        RFC 4303 Appendix A2. Case A
+
+        a-c: possible seq num received
+        +: Bl, Tl
+
+        |--a--+---b---+-c--|
+              =========
+              Bl      Tl
+
+        No ESN implies Th = 0
+        Case A implies Tl >= W - 1
+        """
+
+        Tl = anti_replay_window_size + 40
+        Bl = Tl - anti_replay_window_size + 1
+
+        # move VPP's RX AR window to Case A
+        self.vapi.cli(f"test ipsec sa {p.scapy_tra_sa_id} seq {seq_num(Tl):#x}")
+        p.scapy_tra_sa.seq_num = seq_num(Tl)
+
+        """
+        case a: Seql < Bl
+            - pre-crypto check: algorithm predicts that the packet is out of window
+                -> packet should be dropped
+            - integrity check: ...
+            - post-crypto check: ...
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Bl - 20), seq_num(Bl - 5))
+        ]
+
+        # out-of-window packets
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
+        replay_count += len(pkts)
+        self.assertEqual(self.get_replay_counts(p), replay_count)
+
+        """
+            case b: Bl <= Seql <= Tl
+                - pre-crypto check: algorithm predicts that the packet is in the window
+                    -> check for a replayed packet with Seql
+                - integrity check: should pass
+                - post-crypto check:
+                    -> check for a replayed packet with Seql
+        """
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Tl - 50), seq_num(Tl - 30))
+        ]
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        pkts = [
+            (
+                Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
+                / p.scapy_tra_sa.encrypt(
+                    IP(src=self.tra_if.remote_ip4, dst=self.tra_if.local_ip4) / ICMP(),
+                    seq_num=seq,
+                )
+            )
+            for seq in range(seq_num(Tl - 35), seq_num(Tl - 30))
+        ]
+
+        self.send_and_assert_no_replies(self.tra_if, pkts, timeout=0.2)
 
-        # lost of holes in the sequence
+        # replayed packets
+        replay_count += 5
+        self.assertEqual(self.get_replay_counts(p), replay_count)
+
+        """
+            case c: Seql > Tl
+                - pre-crypto check: algorithm predicts that the packet will shift the window
+                - integrity check: should pass
+                - post-crypto check: should pass
+                    -> AR window is shifted
+        """
         pkts = [
             (
                 Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
@@ -948,10 +1780,34 @@ class IpsecTra4(object):
                     seq_num=seq,
                 )
             )
-            for seq in range(100, 200, 2)
+            for seq in range(seq_num(Tl + 5), seq_num(Tl + 20))
         ]
-        self.send_and_expect(self.tra_if, pkts, self.tra_if, n_rx=50)
 
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
+
+        """
+            RFC 4303 Appendix A2. Case B
+
+            |-a-----+------b-----|
+            =========
+                    Tl
+
+            Case B implies Tl < W - 1
+        """
+
+        # reset the VPP's RX AR window to Case B
+        Tl = 30  # minimum window size of 64, we are sure to overlap
+        Bl = seq_num(Tl - anti_replay_window_size + 1)
+
+        self.vapi.cli(f"test ipsec sa {p.scapy_tra_sa_id} seq {seq_num(Tl):#x}")
+
+        """
+        case a: Seql <= Tl < Bl
+            - pre-crypto check: algorithm predicts that the packet is in the window
+                -> check for replayed packet
+            - integrity check: should fail
+            - post-crypto check: ...
+        """
         pkts = [
             (
                 Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
@@ -960,13 +1816,18 @@ class IpsecTra4(object):
                     seq_num=seq,
                 )
             )
-            for seq in range(200, 300)
+            for seq in range(seq_num(5), seq_num(10))
         ]
-        self.send_and_expect(self.tra_if, pkts, self.tra_if)
 
-        self.assertEqual(p.tra_sa_out.get_lost(), 51)
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
 
-        # a big hole in the seq number space
+        """
+            case b: Tl < Seql < Bl
+                - pre-crypto check: algorithm predicts that the packet will shift the window
+                - integrity check: should pass
+                - post-crypto check: should pass
+                    -> AR window is shifted
+        """
         pkts = [
             (
                 Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac)
@@ -975,54 +1836,16 @@ class IpsecTra4(object):
                     seq_num=seq,
                 )
             )
-            for seq in range(400, 500)
+            for seq in range(seq_num(-50), seq_num(-20))
         ]
-        self.send_and_expect(self.tra_if, pkts, self.tra_if)
-
-        self.assertEqual(p.tra_sa_out.get_lost(), 151)
-
-    def verify_tra_basic4(self, count=1, payload_size=54):
-        """ipsec v4 transport basic test"""
-        self.vapi.cli("clear errors")
-        self.vapi.cli("clear ipsec sa")
-        try:
-            p = self.params[socket.AF_INET]
-            send_pkts = self.gen_encrypt_pkts(
-                p,
-                p.scapy_tra_sa,
-                self.tra_if,
-                src=self.tra_if.remote_ip4,
-                dst=self.tra_if.local_ip4,
-                count=count,
-                payload_size=payload_size,
-            )
-            recv_pkts = self.send_and_expect(self.tra_if, send_pkts, self.tra_if)
-            for rx in recv_pkts:
-                self.assertEqual(len(rx) - len(Ether()), rx[IP].len)
-                self.assert_packet_checksums_valid(rx)
-                try:
-                    decrypted = p.vpp_tra_sa.decrypt(rx[IP])
-                    self.assert_packet_checksums_valid(decrypted)
-                except:
-                    self.logger.debug(ppp("Unexpected packet:", rx))
-                    raise
-        finally:
-            self.logger.info(self.vapi.ppcli("show error"))
-            self.logger.info(self.vapi.ppcli("show ipsec all"))
 
-        pkts = p.tra_sa_in.get_stats()["packets"]
-        self.assertEqual(
-            pkts, count, "incorrect SA in counts: expected %d != %d" % (count, pkts)
-        )
-        pkts = p.tra_sa_out.get_stats()["packets"]
-        self.assertEqual(
-            pkts, count, "incorrect SA out counts: expected %d != %d" % (count, pkts)
-        )
-        self.assertEqual(p.tra_sa_out.get_lost(), 0)
-        self.assertEqual(p.tra_sa_in.get_lost(), 0)
+        self.send_and_expect(self.tra_if, pkts, self.tra_if)
 
-        self.assert_packet_counter_equal(self.tra4_encrypt_node_name, count)
-        self.assert_packet_counter_equal(self.tra4_decrypt_node_name[0], count)
+    def verify_tra_anti_replay_algorithm(self):
+        if self.params[socket.AF_INET].vpp_tra_sa.esn_en:
+            self._verify_tra_anti_replay_algorithm_esn()
+        else:
+            self._verify_tra_anti_replay_algorithm_no_esn()
 
 
 class IpsecTra4Tests(IpsecTra4):
@@ -1032,6 +1855,10 @@ class IpsecTra4Tests(IpsecTra4):
         """ipsec v4 transport anti-replay test"""
         self.verify_tra_anti_replay()
 
+    def test_tra_anti_replay_algorithm(self):
+        """ipsec v4 transport anti-replay algorithm test"""
+        self.verify_tra_anti_replay_algorithm()
+
     def test_tra_lost(self):
         """ipsec v4 transport lost packet test"""
         self.verify_tra_lost()
@@ -1273,7 +2100,7 @@ class IpsecTun4(object):
         decrypt_pkts = []
         for rx in rxs:
             if p.nat_header:
-                self.assertEqual(rx[UDP].dport, 4500)
+                self.assertEqual(rx[UDP].dport, p.nat_header.dport)
             self.assert_packet_checksums_valid(rx)
             self.assertEqual(len(rx) - len(Ether()), rx[IP].len)
             try:
@@ -1459,7 +2286,7 @@ class IpsecTun4(object):
         )
         self.send_and_assert_no_replies(self.tun_if, pkt * 31)
         self.assert_error_counter_equal(
-            "/err/%s/NAT Keepalive" % self.tun4_input_node, 31
+            "/err/%s/nat_keepalive" % self.tun4_input_node, 31
         )
 
         pkt = (
@@ -1469,7 +2296,7 @@ class IpsecTun4(object):
             / Raw(b"\xfe")
         )
         self.send_and_assert_no_replies(self.tun_if, pkt * 31)
-        self.assert_error_counter_equal("/err/%s/Too Short" % self.tun4_input_node, 31)
+        self.assert_error_counter_equal("/err/%s/too_short" % self.tun4_input_node, 31)
 
         pkt = (
             Ether(src=self.tun_if.remote_mac, dst=self.tun_if.local_mac)
@@ -1479,7 +2306,7 @@ class IpsecTun4(object):
             / Padding(0 * 21)
         )
         self.send_and_assert_no_replies(self.tun_if, pkt * 31)
-        self.assert_error_counter_equal("/err/%s/Too Short" % self.tun4_input_node, 62)
+        self.assert_error_counter_equal("/err/%s/too_short" % self.tun4_input_node, 62)
 
 
 class IpsecTun4Tests(IpsecTun4):
@@ -1705,6 +2532,40 @@ class IpsecTun6(object):
             self.logger.info(self.vapi.ppcli("show ipsec all"))
         self.verify_counters6(p, p, count)
 
+    def verify_keepalive(self, p):
+        # the sizeof Raw is calculated to pad to the minimum ehternet
+        # frame size of 64 btyes
+        pkt = (
+            Ether(src=self.tun_if.remote_mac, dst=self.tun_if.local_mac)
+            / IPv6(src=p.remote_tun_if_host, dst=self.tun_if.local_ip6)
+            / UDP(sport=333, dport=4500)
+            / Raw(b"\xff")
+            / Padding(0 * 1)
+        )
+        self.send_and_assert_no_replies(self.tun_if, pkt * 31)
+        self.assert_error_counter_equal(
+            "/err/%s/nat_keepalive" % self.tun6_input_node, 31
+        )
+
+        pkt = (
+            Ether(src=self.tun_if.remote_mac, dst=self.tun_if.local_mac)
+            / IPv6(src=p.remote_tun_if_host, dst=self.tun_if.local_ip6)
+            / UDP(sport=333, dport=4500)
+            / Raw(b"\xfe")
+        )
+        self.send_and_assert_no_replies(self.tun_if, pkt * 31)
+        self.assert_error_counter_equal("/err/%s/too_short" % self.tun6_input_node, 31)
+
+        pkt = (
+            Ether(src=self.tun_if.remote_mac, dst=self.tun_if.local_mac)
+            / IPv6(src=p.remote_tun_if_host, dst=self.tun_if.local_ip6)
+            / UDP(sport=333, dport=4500)
+            / Raw(b"\xfe")
+            / Padding(0 * 21)
+        )
+        self.send_and_assert_no_replies(self.tun_if, pkt * 31)
+        self.assert_error_counter_equal("/err/%s/too_short" % self.tun6_input_node, 62)
+
 
 class IpsecTun6Tests(IpsecTun6):
     """UT test methods for Tunnel v6"""
@@ -1888,6 +2749,15 @@ class IPSecIPv4Fwd(VppTestCase):
         policy_type,
         remove=False,
         all_ips=False,
+        ip_range=False,
+        local_ip_start=ip_address("0.0.0.0"),
+        local_ip_stop=ip_address("255.255.255.255"),
+        remote_ip_start=ip_address("0.0.0.0"),
+        remote_ip_stop=ip_address("255.255.255.255"),
+        remote_port_start=0,
+        remote_port_stop=65535,
+        local_port_start=0,
+        local_port_stop=65535,
     ):
         spd = VppIpsecSpd(self, spd_id)
 
@@ -1896,6 +2766,13 @@ class IPSecIPv4Fwd(VppTestCase):
             src_range_high = ip_address("255.255.255.255")
             dst_range_low = ip_address("0.0.0.0")
             dst_range_high = ip_address("255.255.255.255")
+
+        elif ip_range:
+            src_range_low = local_ip_start
+            src_range_high = local_ip_stop
+            dst_range_low = remote_ip_start
+            dst_range_high = remote_ip_stop
+
         else:
             src_range_low = src_if.remote_ip4
             src_range_high = src_if.remote_ip4
@@ -1914,6 +2791,10 @@ class IPSecIPv4Fwd(VppTestCase):
             priority=priority,
             policy=self.get_policy(policy_type),
             is_outbound=is_out,
+            remote_port_start=remote_port_start,
+            remote_port_stop=remote_port_stop,
+            local_port_start=local_port_start,
+            local_port_stop=local_port_stop,
         )
 
         if remove is False:
@@ -2068,5 +2949,200 @@ class SpdFlowCacheTemplate(IPSecIPv4Fwd):
             return False
 
 
+class IPSecIPv6Fwd(VppTestCase):
+    """Test IPSec by capturing and verifying IPv6 forwarded pkts"""
+
+    @classmethod
+    def setUpConstants(cls):
+        super(IPSecIPv6Fwd, cls).setUpConstants()
+
+    def setUp(self):
+        super(IPSecIPv6Fwd, self).setUp()
+        # store SPD objects so we can remove configs on tear down
+        self.spd_objs = []
+        self.spd_policies = []
+
+    def tearDown(self):
+        # remove SPD policies
+        for obj in self.spd_policies:
+            obj.remove_vpp_config()
+        self.spd_policies = []
+        # remove SPD items (interface bindings first, then SPD)
+        for obj in reversed(self.spd_objs):
+            obj.remove_vpp_config()
+        self.spd_objs = []
+        # close down pg intfs
+        for pg in self.pg_interfaces:
+            pg.unconfig_ip6()
+            pg.admin_down()
+        super(IPSecIPv6Fwd, self).tearDown()
+
+    def create_interfaces(self, num_ifs=2):
+        # create interfaces pg0 ... pg<num_ifs>
+        self.create_pg_interfaces(range(num_ifs))
+        for pg in self.pg_interfaces:
+            # put the interface up
+            pg.admin_up()
+            # configure IPv6 address on the interface
+            pg.config_ip6()
+            pg.resolve_ndp()
+        self.logger.info(self.vapi.ppcli("show int addr"))
+
+    def spd_create_and_intf_add(self, spd_id, pg_list):
+        spd = VppIpsecSpd(self, spd_id)
+        spd.add_vpp_config()
+        self.spd_objs.append(spd)
+        for pg in pg_list:
+            spdItf = VppIpsecSpdItfBinding(self, spd, pg)
+            spdItf.add_vpp_config()
+            self.spd_objs.append(spdItf)
+
+    def get_policy(self, policy_type):
+        e = VppEnum.vl_api_ipsec_spd_action_t
+        if policy_type == "protect":
+            return e.IPSEC_API_SPD_ACTION_PROTECT
+        elif policy_type == "bypass":
+            return e.IPSEC_API_SPD_ACTION_BYPASS
+        elif policy_type == "discard":
+            return e.IPSEC_API_SPD_ACTION_DISCARD
+        else:
+            raise Exception("Invalid policy type: %s", policy_type)
+
+    def spd_add_rem_policy(
+        self,
+        spd_id,
+        src_if,
+        dst_if,
+        proto,
+        is_out,
+        priority,
+        policy_type,
+        remove=False,
+        all_ips=False,
+        ip_range=False,
+        local_ip_start=ip_address("0::0"),
+        local_ip_stop=ip_address("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff"),
+        remote_ip_start=ip_address("0::0"),
+        remote_ip_stop=ip_address("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff"),
+        remote_port_start=0,
+        remote_port_stop=65535,
+        local_port_start=0,
+        local_port_stop=65535,
+    ):
+        spd = VppIpsecSpd(self, spd_id)
+
+        if all_ips:
+            src_range_low = ip_address("0::0")
+            src_range_high = ip_address("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
+            dst_range_low = ip_address("0::0")
+            dst_range_high = ip_address("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
+
+        elif ip_range:
+            src_range_low = local_ip_start
+            src_range_high = local_ip_stop
+            dst_range_low = remote_ip_start
+            dst_range_high = remote_ip_stop
+
+        else:
+            src_range_low = src_if.remote_ip6
+            src_range_high = src_if.remote_ip6
+            dst_range_low = dst_if.remote_ip6
+            dst_range_high = dst_if.remote_ip6
+
+        spdEntry = VppIpsecSpdEntry(
+            self,
+            spd,
+            0,
+            src_range_low,
+            src_range_high,
+            dst_range_low,
+            dst_range_high,
+            proto,
+            priority=priority,
+            policy=self.get_policy(policy_type),
+            is_outbound=is_out,
+            remote_port_start=remote_port_start,
+            remote_port_stop=remote_port_stop,
+            local_port_start=local_port_start,
+            local_port_stop=local_port_stop,
+        )
+
+        if remove is False:
+            spdEntry.add_vpp_config()
+            self.spd_policies.append(spdEntry)
+        else:
+            spdEntry.remove_vpp_config()
+            self.spd_policies.remove(spdEntry)
+        self.logger.info(self.vapi.ppcli("show ipsec all"))
+        return spdEntry
+
+    def create_stream(self, src_if, dst_if, pkt_count, src_prt=1234, dst_prt=5678):
+        packets = []
+        for i in range(pkt_count):
+            # create packet info stored in the test case instance
+            info = self.create_packet_info(src_if, dst_if)
+            # convert the info into packet payload
+            payload = self.info_to_payload(info)
+            # create the packet itself
+            p = (
+                Ether(dst=src_if.local_mac, src=src_if.remote_mac)
+                / IPv6(src=src_if.remote_ip6, dst=dst_if.remote_ip6)
+                / UDP(sport=src_prt, dport=dst_prt)
+                / Raw(payload)
+            )
+            # store a copy of the packet in the packet info
+            info.data = p.copy()
+            # append the packet to the list
+            packets.append(p)
+        # return the created packet list
+        return packets
+
+    def verify_capture(self, src_if, dst_if, capture):
+        packet_info = None
+        for packet in capture:
+            try:
+                ip = packet[IPv6]
+                udp = packet[UDP]
+                # convert the payload to packet info object
+                payload_info = self.payload_to_info(packet)
+                # make sure the indexes match
+                self.assert_equal(
+                    payload_info.src, src_if.sw_if_index, "source sw_if_index"
+                )
+                self.assert_equal(
+                    payload_info.dst, dst_if.sw_if_index, "destination sw_if_index"
+                )
+                packet_info = self.get_next_packet_info_for_interface2(
+                    src_if.sw_if_index, dst_if.sw_if_index, packet_info
+                )
+                # make sure we didn't run out of saved packets
+                self.assertIsNotNone(packet_info)
+                self.assert_equal(
+                    payload_info.index, packet_info.index, "packet info index"
+                )
+                saved_packet = packet_info.data  # fetch the saved packet
+                # assert the values match
+                self.assert_equal(ip.src, saved_packet[IPv6].src, "IP source address")
+                # ... more assertions here
+                self.assert_equal(udp.sport, saved_packet[UDP].sport, "UDP source port")
+            except Exception as e:
+                self.logger.error(ppp("Unexpected or invalid packet:", packet))
+                raise
+        remaining_packet = self.get_next_packet_info_for_interface2(
+            src_if.sw_if_index, dst_if.sw_if_index, packet_info
+        )
+        self.assertIsNone(
+            remaining_packet,
+            "Interface %s: Packet expected from interface "
+            "%s didn't arrive" % (dst_if.name, src_if.name),
+        )
+
+    def verify_policy_match(self, pkt_count, spdEntry):
+        self.logger.info("XXXX %s %s", str(spdEntry), str(spdEntry.get_stats()))
+        matched_pkts = spdEntry.get_stats().get("packets")
+        self.logger.info("Policy %s matched: %d pkts", str(spdEntry), matched_pkts)
+        self.assert_equal(pkt_count, matched_pkts)
+
+
 if __name__ == "__main__":
     unittest.main(testRunner=VppTestRunner)