ipsec: Performance improvement of ipsec4_output_node using flow cache

Adding flow cache support to improve outbound IPv4/IPSec SPD lookup
performance. Details about flow cache:
  Mechanism:
  1. First packet of a flow will undergo linear search in SPD
     table. Once a policy match is found, a new entry will be added
     into the flow cache. From 2nd packet onwards, the policy lookup
     will happen in flow cache.
  2. The flow cache is implemented using bihash without collision
     handling. This will avoid the logic to age out or recycle the old
     flows in flow cache. Whenever a collision occurs, old entry will
     be overwritten by the new entry. Worst case is when all the 256
     packets in a batch result in collision and fall back to linear
     search. Average and best case will be O(1).
  3. The size of flow cache is fixed and decided based on the number
     of flows to be supported. The default is set to 1 million flows.
     This can be made as a configurable option as a next step.
  4. Whenever a SPD rule is added/deleted by the control plane, the
     flow cache entries will be completely deleted (reset) in the
     control plane. The assumption here is that SPD rule add/del is not
     a frequent operation from control plane. Flow cache reset is done,
     by putting the data plane in fall back mode, to bypass flow cache
     and do linear search till the SPD rule add/delete operation is
     complete. Once the rule is successfully added/deleted, the data
     plane will be allowed to make use of the flow cache. The flow
     cache will be reset only after flushing out the inflight packets
     from all the worker cores using
     vlib_worker_wait_one_loop().

  Details about bihash usage:
  1. A new bihash template (16_8) is added to support IPv4 5 tuple.
     BIHASH_KVP_PER_PAGE and BIHASH_KVP_AT_BUCKET_LEVEL are set
     to 1 in the new template. It means only one KVP is supported
     per bucket.
  2. Collision handling is avoided by calling
     BV (clib_bihash_add_or_overwrite_stale) function.
     Through the stale callback function pointer, the KVP entry
     will be overwritten during collision.
  3. Flow cache reset is done using
     BV (clib_bihash_foreach_key_value_pair) function.
     Through the callback function pointer, the KVP value is reset
     to ~0ULL.

  MRR performance numbers with 1 core, 1 ESP Tunnel, null-encrypt,
  64B for different SPD policy matching indices:

  SPD Policy index    : 1          10         100        1000
  Throughput          : MPPS/MPPS  MPPS/MPPS  MPPS/MPPS  KPPS/MPPS
  (Baseline/Optimized)
  ARM Neoverse N1     : 5.2/4.84   4.55/4.84  2.11/4.84  329.5/4.84
  ARM TX2             : 2.81/2.6   2.51/2.6   1.27/2.6   176.62/2.6
  INTEL SKX           : 4.93/4.48  4.29/4.46  2.05/4.48  336.79/4.47

  Next Steps:
  Following can be made as a configurable option through startup
  conf at IPSec level:
  1. Enable/Disable Flow cache.
  2. Bihash configuration like number of buckets and memory size.
  3. Dual/Quad loop unroll can be applied around bihash to further
     improve the performance.
  4. The same flow cache logic can be applied for IPv6 as well as in
     IPSec inbound direction. A deeper and wider flow cache using
     bihash_40_8 can replace existing bihash_16_8, to make it
     common for both IPv4 and IPv6 in both outbound and
     inbound directions.

Following changes are made based on the review comments:
1. ON/OFF flow cache through startup conf. Default: OFF
2. Flow cache stale entry detection using epoch counter.
3. Avoid host order endianness conversion during flow cache
   lookup.
4. Move IPSec startup conf to a common file.
5. Added SPD flow cache unit test case
6. Replaced bihash with vectors to implement flow cache.
7. ipsec_add_del_policy API is not mpsafe. Cleaned up
   inflight packets check in control plane.

Type: improvement
Signed-off-by: mgovind <govindarajan.Mohandoss@arm.com>
Signed-off-by: Zachary Leaf <zachary.leaf@arm.com>
Tested-by: Jieqiang Wang <jieqiang.wang@arm.com>
Change-Id: I62b4d6625fbc6caf292427a5d2046aa5672b2006

1 files changed, 211 insertions, 0 deletions

diff --git a/test/template_ipsec.py b/test/template_ipsec.py
index e4797353ecd..d9a9d1b78c1 100644
--- a/test/template_ipsec.py
+++ b/test/template_ipsec.py
@@ -14,6 +14,12 @@ from framework import VppTestCase, VppTestRunner
 from util import ppp, reassemble4, fragment_rfc791, fragment_rfc8200
 from vpp_papi import VppEnum
 
+from vpp_ipsec import VppIpsecSpd, VppIpsecSpdEntry, \
+    VppIpsecSpdItfBinding
+from ipaddress import ip_address
+from re import search
+from os import popen
+
 
 class IPsecIPv4Params:
 
@@ -1571,5 +1577,210 @@ class IpsecTun46Tests(IpsecTun4Tests, IpsecTun6Tests):
     pass
 
 
+class SpdFlowCacheTemplate(VppTestCase):
+    @classmethod
+    def setUpConstants(cls):
+        super(SpdFlowCacheTemplate, cls).setUpConstants()
+        # Override this method with required cmdline parameters e.g.
+        # cls.vpp_cmdline.extend(["ipsec", "{",
+        #                         "ipv4-outbound-spd-flow-cache on",
+        #                         "}"])
+        # cls.logger.info("VPP modified cmdline is %s" % " "
+        #                 .join(cls.vpp_cmdline))
+
+    def setUp(self):
+        super(SpdFlowCacheTemplate, 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_ip4()
+            pg.admin_down()
+        super(SpdFlowCacheTemplate, 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 IPv4 address on the interface
+            pg.config_ip4()
+            # resolve ARP, so that we know VPP MAC
+            pg.resolve_arp()
+        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):
+        spd = VppIpsecSpd(self, spd_id)
+
+        if all_ips:
+            src_range_low = ip_address("0.0.0.0")
+            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")
+        else:
+            src_range_low = src_if.remote_ip4
+            src_range_high = src_if.remote_ip4
+            dst_range_low = dst_if.remote_ip4
+            dst_range_high = dst_if.remote_ip4
+
+        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)
+
+        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) /
+                 IP(src=src_if.remote_ip4, dst=dst_if.remote_ip4) /
+                 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[IP]
+                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[IP].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)
+
+    def get_spd_flow_cache_entries(self):
+        """ 'show ipsec spd' output:
+        ip4-outbound-spd-flow-cache-entries: 0
+        """
+        show_ipsec_reply = self.vapi.cli("show ipsec spd")
+        # match the relevant section of 'show ipsec spd' output
+        regex_match = re.search(
+            'ip4-outbound-spd-flow-cache-entries: (.*)',
+            show_ipsec_reply, re.DOTALL)
+        if regex_match is None:
+            raise Exception("Unable to find spd flow cache entries \
+                in \'show ipsec spd\' CLI output - regex failed to match")
+        else:
+            try:
+                num_entries = int(regex_match.group(1))
+            except ValueError:
+                raise Exception("Unable to get spd flow cache entries \
+                from \'show ipsec spd\' string: %s", regex_match.group(0))
+            self.logger.info("%s", regex_match.group(0))
+        return num_entries
+
+    def verify_num_outbound_flow_cache_entries(self, expected_elements):
+        self.assertEqual(self.get_spd_flow_cache_entries(), expected_elements)
+
+    def crc32_supported(self):
+        # lscpu is part of util-linux package, available on all Linux Distros
+        stream = os.popen('lscpu')
+        cpu_info = stream.read()
+        # feature/flag "crc32" on Aarch64 and "sse4_2" on x86
+        # see vppinfra/crc32.h
+        if "crc32" or "sse4_2" in cpu_info:
+            self.logger.info("\ncrc32 supported:\n" + cpu_info)
+            return True
+        else:
+            self.logger.info("\ncrc32 NOT supported:\n" + cpu_info)
+            return False
+
+
 if __name__ == '__main__':
     unittest.main(testRunner=VppTestRunner)