devices: add support for pseudo header checksum

Type: improvement

Linux uses pseudo header checksum when checksum of l4 is offloaded.
This patch adds similar support in virtual interfaces.

Change-Id: I6a94d1104e59356f95057e7c122e3be9cd8659a3
Signed-off-by: Aloys Augustin <aloaugus@cisco.com>
Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>

8 files changed, 371 insertions, 23 deletions

diff --git a/src/plugins/unittest/CMakeLists.txt b/src/plugins/unittest/CMakeLists.txt
index e39a240612f..0a6602df079 100644
--- a/src/plugins/unittest/CMakeLists.txt
+++ b/src/plugins/unittest/CMakeLists.txt
@@ -35,6 +35,7 @@ add_vpp_plugin(unittest
   hash_test.c
   interface_test.c
   ipsec_test.c
+  ip_psh_cksum_test.c
   llist_test.c
   mactime_test.c
   mem_bulk_test.c
diff --git a/src/plugins/unittest/ip_psh_cksum_test.c b/src/plugins/unittest/ip_psh_cksum_test.c
new file mode 100644
index 00000000000..7a0e1c3a1f4
--- /dev/null
+++ b/src/plugins/unittest/ip_psh_cksum_test.c
@@ -0,0 +1,266 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2021 Cisco Systems, Inc.
+ */
+
+#include <vlib/vlib.h>
+#include <vppinfra/time.h>
+#include <vppinfra/cache.h>
+#include <vppinfra/error.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/ip/ip.h>
+#include <vnet/ip/ip_psh_cksum.h>
+
+static_always_inline void
+compute_ip_phc (void *p)
+{
+  if ((((u8 *) p)[0] & 0xf0) == 0x40)
+    ip4_pseudo_header_cksum (p);
+  else if ((((u8 *) p)[0] & 0xf0) == 0x60)
+    ip6_pseudo_header_cksum (p);
+}
+
+void
+compute_ip_phc_func (void **p, u32 n_packets)
+{
+  u32 n_left_from = n_packets;
+
+  while (n_left_from >= 8)
+    {
+      clib_prefetch_load (p[4]);
+      clib_prefetch_load (p[5]);
+      clib_prefetch_load (p[6]);
+      clib_prefetch_load (p[7]);
+
+      compute_ip_phc (p[0]);
+      compute_ip_phc (p[1]);
+      compute_ip_phc (p[2]);
+      compute_ip_phc (p[3]);
+
+      n_left_from -= 4;
+      p += 4;
+    }
+
+  while (n_left_from > 0)
+    {
+      compute_ip_phc (p[0]);
+
+      n_left_from -= 1;
+      p += 1;
+    }
+}
+
+typedef struct _phc_test_data
+{
+  const char *name;
+  const char *description;
+  u8 *data;
+  u32 data_size;
+  struct _phc_test_data *next;
+} phc_test_data_t;
+
+typedef struct
+{
+  int verbose;
+
+  char *phc_name;
+  u32 warmup_rounds;
+  u32 rounds;
+  u32 n_buffers;
+  u32 buffer_size;
+  phc_test_data_t *phc_test_data;
+} phc_test_main_t;
+
+phc_test_main_t phc_test_main;
+
+#define PHC_TEST_REGISTER_DATA(x, ...)                                        \
+  __VA_ARGS__ phc_test_data_t __phc_test_data_##x;                            \
+  static void __clib_constructor __phc_test_data_fn_##x (void)                \
+  {                                                                           \
+    phc_test_main_t *ptm = &phc_test_main;                                    \
+    __phc_test_data_##x.next = ptm->phc_test_data;                            \
+    ptm->phc_test_data = &__phc_test_data_##x;                                \
+  }                                                                           \
+  __VA_ARGS__ phc_test_data_t __phc_test_data_##x
+
+// ipv4
+u8 phc_ipv4_tcp_data[50] = {
+  0x45, 0x00, 0x05, 0xdc, 0xdb, 0x42, 0x40, 0x00, 0x40, 0x06, 0xc4, 0x85, 0xc0,
+  0xa8, 0x0a, 0x02, 0xc0, 0xa8, 0x0a, 0x01, 0xd8, 0xde, 0x14, 0x51, 0x34, 0x93,
+  0xa8, 0x1b, 0x7b, 0xef, 0x2e, 0x7e, 0x80, 0x10, 0x00, 0xe5, 0xc7, 0x03, 0x00,
+  0x00, 0x01, 0x01, 0x08, 0x0a, 0xce, 0xaa, 0x00, 0x2f, 0xf2, 0xc3
+};
+
+PHC_TEST_REGISTER_DATA (ipv4_tcp, static) = {
+  .name = "ipv4-tcp",
+  .description = "IPv4 TCP",
+  .data = phc_ipv4_tcp_data,
+  .data_size = sizeof (phc_ipv4_tcp_data),
+};
+
+// ip6
+u8 phc_ipv6_udp_data[65] = {
+  0x60, 0x0d, 0xf4, 0x97, 0x00, 0x40, 0x3a, 0x40, 0xfd, 0x01, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0xfd, 0x01,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
+  0x01, 0x80, 0x00, 0x10, 0x84, 0xb1, 0x25, 0x00, 0x01, 0x22, 0x57, 0xf0, 0x60,
+  0x00, 0x00, 0x00, 0x00, 0xcb, 0x4a, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10,
+};
+
+PHC_TEST_REGISTER_DATA (ipv6_udp, static) = {
+  .name = "ipv6-udp",
+  .description = "IPv6 UDP",
+  .data = phc_ipv6_udp_data,
+  .data_size = sizeof (phc_ipv6_udp_data),
+};
+
+static void
+fill_buffers (vlib_main_t *vm, u32 *buffer_indices, u8 *data, u32 data_size,
+	      u32 n_buffers, u32 buffer_size)
+{
+  int i, j;
+  u64 seed = clib_cpu_time_now ();
+  for (i = 0; i < n_buffers; i++)
+    {
+      vlib_buffer_t *b = vlib_get_buffer (vm, buffer_indices[i]);
+      clib_memcpy_fast (b->data, data, data_size);
+      b->current_data = 0;
+      for (j = data_size; j < buffer_size; j += 8)
+	*(u64 *) (b->data + j) = 1 + random_u64 (&seed);
+      b->current_length = buffer_size;
+    }
+}
+
+static clib_error_t *
+test_phc_perf (vlib_main_t *vm, phc_test_main_t *ptm)
+{
+  clib_error_t *err = 0;
+  u32 buffer_size = vlib_buffer_get_default_data_size (vm);
+  u32 n_buffers, n_alloc = 0, warmup_rounds, rounds;
+  u32 *buffer_indices = 0;
+  u64 t0[5], t1[5];
+  phc_test_data_t *phc_test_data = ptm->phc_test_data;
+  void **p = 0;
+  int i, j;
+
+  if (ptm->buffer_size > buffer_size)
+    return clib_error_return (0, "buffer size must be <= %u", buffer_size);
+
+  rounds = ptm->rounds ? ptm->rounds : 100;
+  n_buffers = ptm->n_buffers ? ptm->n_buffers : 256;
+  warmup_rounds = ptm->warmup_rounds ? ptm->warmup_rounds : 100;
+  buffer_size = ptm->buffer_size ? ptm->buffer_size : buffer_size;
+
+  vec_validate_aligned (p, n_buffers - 1, CLIB_CACHE_LINE_BYTES);
+  vec_validate_aligned (buffer_indices, n_buffers - 1, CLIB_CACHE_LINE_BYTES);
+  n_alloc = vlib_buffer_alloc (vm, buffer_indices, n_buffers);
+  if (n_alloc != n_buffers)
+    {
+      err = clib_error_return (0, "buffer alloc failure");
+      goto done;
+    }
+
+  vlib_cli_output (
+    vm,
+    "pseudo header checksum: buffer-size %u, n_buffers %u rounds %u "
+    "warmup-rounds %u",
+    buffer_size, n_buffers, rounds, warmup_rounds);
+  vlib_cli_output (vm, "   cpu-freq %.2f GHz",
+		   (f64) vm->clib_time.clocks_per_second * 1e-9);
+
+  while (phc_test_data)
+    {
+      fill_buffers (vm, buffer_indices, phc_test_data->data,
+		    phc_test_data->data_size, n_buffers, buffer_size);
+
+      for (i = 0; i < n_buffers; i++)
+	{
+	  vlib_buffer_t *b = vlib_get_buffer (vm, buffer_indices[i]);
+	  p[i] = vlib_buffer_get_current (b);
+	}
+
+      for (i = 0; i < 5; i++)
+	{
+	  for (j = 0; j < warmup_rounds; j++)
+	    {
+	      compute_ip_phc_func (p, n_buffers);
+	    }
+
+	  t0[i] = clib_cpu_time_now ();
+	  for (j = 0; j < rounds; j++)
+	    compute_ip_phc_func (p, n_buffers);
+	  t1[i] = clib_cpu_time_now ();
+	}
+
+      vlib_cli_output (
+	vm, "===========================================================");
+      vlib_cli_output (vm, " Test: %s", phc_test_data->description);
+      vlib_cli_output (
+	vm, "===========================================================");
+      for (i = 0; i < 5; i++)
+	{
+	  f64 tpp1 = (f64) (t1[i] - t0[i]) / (n_buffers * rounds);
+	  f64 Mpps1 = vm->clib_time.clocks_per_second * 1e-6 / tpp1;
+
+	  vlib_cli_output (vm, "%-2u: %.03f ticks/packet, %.02f Mpps\n", i + 1,
+			   tpp1, Mpps1);
+	}
+      phc_test_data = phc_test_data->next;
+    }
+
+done:
+  if (n_alloc)
+    vlib_buffer_free (vm, buffer_indices, n_alloc);
+
+  vec_free (p);
+  vec_free (buffer_indices);
+  return err;
+}
+
+static clib_error_t *
+test_phc_command_fn (vlib_main_t *vm, unformat_input_t *input,
+		     vlib_cli_command_t *cmd)
+{
+  phc_test_main_t *ptm = &phc_test_main;
+  clib_error_t *err = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "verbose"))
+	ptm->verbose = 1;
+      else if (unformat (input, "detail"))
+	ptm->verbose = 2;
+      else if (unformat (input, "buffers %u", &ptm->n_buffers))
+	;
+      else if (unformat (input, "buffer-size %u", &ptm->buffer_size))
+	;
+      else if (unformat (input, "rounds %u", &ptm->rounds))
+	;
+      else if (unformat (input, "warmup-rounds %u", &ptm->warmup_rounds))
+	;
+      else
+	{
+	  return clib_error_return (0, "unknown input '%U'",
+				    format_unformat_error, input);
+	}
+    }
+
+  test_phc_perf (vm, ptm);
+
+  return err;
+}
+
+VLIB_CLI_COMMAND (test_phc_command, static) = {
+  .path = "test phc",
+  .short_help = "test phc [buffers <n>] [buffer-size <size>] [rounds <n>] "
+		"[warmup-rounds <n>]",
+  .function = test_phc_command_fn,
+};
+
+static clib_error_t *
+phc_test_init (vlib_main_t *vm)
+{
+  return (0);
+}
+
+VLIB_INIT_FUNCTION (phc_test_init);
diff --git a/src/plugins/vmxnet3/input.c b/src/plugins/vmxnet3/input.c
index 3015fb116ca..25d39ddaf91 100644
--- a/src/plugins/vmxnet3/input.c
+++ b/src/plugins/vmxnet3/input.c
@@ -106,19 +106,11 @@ vmxnet3_handle_offload (vmxnet3_rx_comp * rx_comp, vlib_buffer_t * hb,
 	    {
 	      if (rx_comp->flags & VMXNET3_RXCF_TCP)
 		{
-		  tcp_header_t *tcp =
-		    (tcp_header_t *) (hb->data +
-				      vnet_buffer (hb)->l4_hdr_offset);
 		  oflags |= VNET_BUFFER_OFFLOAD_F_TCP_CKSUM;
-		  tcp->checksum = 0;
 		}
 	      else if (rx_comp->flags & VMXNET3_RXCF_UDP)
 		{
-		  udp_header_t *udp =
-		    (udp_header_t *) (hb->data +
-				      vnet_buffer (hb)->l4_hdr_offset);
 		  oflags |= VNET_BUFFER_OFFLOAD_F_UDP_CKSUM;
-		  udp->checksum = 0;
 		}
 	    }
 	}
diff --git a/src/vnet/CMakeLists.txt b/src/vnet/CMakeLists.txt
index 7b01d941d38..5e1cbc24fd1 100644
--- a/src/vnet/CMakeLists.txt
+++ b/src/vnet/CMakeLists.txt
@@ -458,6 +458,7 @@ list(APPEND VNET_HEADERS
   ip/ip_table.h
   ip/ip_interface.h
   ip/ip_packet.h
+  ip/ip_psh_cksum.h
   ip/ip_source_and_port_range_check.h
   ip/ip_types.h
   ip/lookup.h
diff --git a/src/vnet/devices/af_packet/node.c b/src/vnet/devices/af_packet/node.c
index caddcfa416b..e2f87b10b35 100644
--- a/src/vnet/devices/af_packet/node.c
+++ b/src/vnet/devices/af_packet/node.c
@@ -132,7 +132,6 @@ mark_tcp_udp_cksum_calc (vlib_buffer_t *b, u8 *l4_hdr_sz)
 	  tcp_header_t *tcp = (tcp_header_t *) (vlib_buffer_get_current (b) +
 						sizeof (ethernet_header_t) +
 						ip4_header_bytes (ip4));
-	  tcp->checksum = 0;
 	  *l4_hdr_sz = tcp_header_bytes (tcp);
 	}
       else if (ip4->protocol == IP_PROTOCOL_UDP)
@@ -141,7 +140,6 @@ mark_tcp_udp_cksum_calc (vlib_buffer_t *b, u8 *l4_hdr_sz)
 	  udp_header_t *udp = (udp_header_t *) (vlib_buffer_get_current (b) +
 						sizeof (ethernet_header_t) +
 						ip4_header_bytes (ip4));
-	  udp->checksum = 0;
 	  *l4_hdr_sz = sizeof (*udp);
 	}
       vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
@@ -172,7 +170,6 @@ mark_tcp_udp_cksum_calc (vlib_buffer_t *b, u8 *l4_hdr_sz)
 	  tcp_header_t *tcp =
 	    (tcp_header_t *) (vlib_buffer_get_current (b) +
 			      sizeof (ethernet_header_t) + ip6_hdr_len);
-	  tcp->checksum = 0;
 	  *l4_hdr_sz = tcp_header_bytes (tcp);
 	}
       else if (ip6->protocol == IP_PROTOCOL_UDP)
@@ -181,7 +178,6 @@ mark_tcp_udp_cksum_calc (vlib_buffer_t *b, u8 *l4_hdr_sz)
 	  udp_header_t *udp =
 	    (udp_header_t *) (vlib_buffer_get_current (b) +
 			      sizeof (ethernet_header_t) + ip6_hdr_len);
-	  udp->checksum = 0;
 	  *l4_hdr_sz = sizeof (*udp);
 	}
       vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
diff --git a/src/vnet/devices/virtio/device.c b/src/vnet/devices/virtio/device.c
index 6c2fe34abf0..ac9be6b02ae 100644
--- a/src/vnet/devices/virtio/device.c
+++ b/src/vnet/devices/virtio/device.c
@@ -27,6 +27,7 @@
 #include <vnet/gso/hdr_offset_parser.h>
 #include <vnet/ip/ip4_packet.h>
 #include <vnet/ip/ip6_packet.h>
+#include <vnet/ip/ip_psh_cksum.h>
 #include <vnet/tcp/tcp_packet.h>
 #include <vnet/udp/udp_packet.h>
 #include <vnet/devices/virtio/virtio.h>
@@ -296,37 +297,60 @@ set_checksum_offsets (vlib_buffer_t *b, virtio_net_hdr_v1_t *hdr,
 					 0 /* ip6 */ );
       hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
       hdr->csum_start = gho.l4_hdr_offset;	// 0x22;
+
+      /*
+       * virtio devices do not support IP4 checksum offload. So driver takes
+       * care of it while doing tx.
+       */
+      ip4 = (ip4_header_t *) (vlib_buffer_get_current (b) + gho.l3_hdr_offset);
+      if (oflags & VNET_BUFFER_OFFLOAD_F_IP_CKSUM)
+	ip4->checksum = ip4_header_checksum (ip4);
+
+      /*
+       * virtio devices assume the l4 header is set to the checksum of the
+       * l3 pseudo-header, so we compute it before tx-ing
+       */
       if (oflags & VNET_BUFFER_OFFLOAD_F_TCP_CKSUM)
 	{
+	  tcp_header_t *tcp =
+	    (tcp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+	  tcp->checksum = ip4_pseudo_header_cksum (ip4);
 	  hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
 	}
       else if (oflags & VNET_BUFFER_OFFLOAD_F_UDP_CKSUM)
 	{
+	  udp_header_t *udp =
+	    (udp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+	  udp->checksum = ip4_pseudo_header_cksum (ip4);
 	  hdr->csum_offset = STRUCT_OFFSET_OF (udp_header_t, checksum);
 	}
-
-      /*
-       * virtio devices do not support IP4 checksum offload. So driver takes care
-       * of it while doing tx.
-       */
-      ip4 =
-	(ip4_header_t *) (vlib_buffer_get_current (b) + gho.l3_hdr_offset);
-      if (oflags & VNET_BUFFER_OFFLOAD_F_IP_CKSUM)
-	ip4->checksum = ip4_header_checksum (ip4);
     }
   else if (b->flags & VNET_BUFFER_F_IS_IP6)
     {
+      ip6_header_t *ip6;
       generic_header_offset_t gho = { 0 };
       vnet_generic_header_offset_parser (b, &gho, is_l2, 0 /* ip4 */ ,
 					 1 /* ip6 */ );
       hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
       hdr->csum_start = gho.l4_hdr_offset;	// 0x36;
+      ip6 = (ip6_header_t *) (vlib_buffer_get_current (b) + gho.l3_hdr_offset);
+
+      /*
+       * virtio devices assume the l4 header is set to the checksum of the
+       * l3 pseudo-header, so we compute it before tx-ing
+       */
       if (oflags & VNET_BUFFER_OFFLOAD_F_TCP_CKSUM)
 	{
+	  tcp_header_t *tcp =
+	    (tcp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+	  tcp->checksum = ip6_pseudo_header_cksum (ip6);
 	  hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
 	}
       else if (oflags & VNET_BUFFER_OFFLOAD_F_UDP_CKSUM)
 	{
+	  udp_header_t *udp =
+	    (udp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+	  udp->checksum = ip6_pseudo_header_cksum (ip6);
 	  hdr->csum_offset = STRUCT_OFFSET_OF (udp_header_t, checksum);
 	}
     }
diff --git a/src/vnet/devices/virtio/vhost_user_output.c b/src/vnet/devices/virtio/vhost_user_output.c
index 4efafa85333..15e39a11692 100644
--- a/src/vnet/devices/virtio/vhost_user_output.c
+++ b/src/vnet/devices/virtio/vhost_user_output.c
@@ -37,6 +37,7 @@
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/devices/devices.h>
 #include <vnet/feature/feature.h>
+#include <vnet/ip/ip_psh_cksum.h>
 
 #include <vnet/devices/virtio/vhost_user.h>
 #include <vnet/devices/virtio/vhost_user_inline.h>
@@ -208,27 +209,40 @@ vhost_user_handle_tx_offload (vhost_user_intf_t * vui, vlib_buffer_t * b,
   int is_ip4 = b->flags & VNET_BUFFER_F_IS_IP4;
   int is_ip6 = b->flags & VNET_BUFFER_F_IS_IP6;
   vnet_buffer_oflags_t oflags = vnet_buffer (b)->oflags;
+  u16 psh_cksum = 0;
+  ip4_header_t *ip4 = 0;
+  ip6_header_t *ip6 = 0;
 
   ASSERT (!(is_ip4 && is_ip6));
   vnet_generic_header_offset_parser (b, &gho, 1 /* l2 */ , is_ip4, is_ip6);
   if (oflags & VNET_BUFFER_OFFLOAD_F_IP_CKSUM)
     {
-      ip4_header_t *ip4;
-
       ip4 =
 	(ip4_header_t *) (vlib_buffer_get_current (b) + gho.l3_hdr_offset);
       ip4->checksum = ip4_header_checksum (ip4);
+      psh_cksum = ip4_pseudo_header_cksum (ip4);
+    }
+  else
+    {
+      ip6 = (ip6_header_t *) (vlib_buffer_get_current (b) + gho.l3_hdr_offset);
+      psh_cksum = ip6_pseudo_header_cksum (ip6);
     }
 
   /* checksum offload */
   if (oflags & VNET_BUFFER_OFFLOAD_F_UDP_CKSUM)
     {
+      udp_header_t *udp =
+	(udp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+      udp->checksum = psh_cksum;
       hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
       hdr->csum_start = gho.l4_hdr_offset;
       hdr->csum_offset = offsetof (udp_header_t, checksum);
     }
   else if (oflags & VNET_BUFFER_OFFLOAD_F_TCP_CKSUM)
     {
+      tcp_header_t *tcp =
+	(tcp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+      tcp->checksum = psh_cksum;
       hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
       hdr->csum_start = gho.l4_hdr_offset;
       hdr->csum_offset = offsetof (tcp_header_t, checksum);
diff --git a/src/vnet/ip/ip_psh_cksum.h b/src/vnet/ip/ip_psh_cksum.h
new file mode 100644
index 00000000000..eaac401f223
--- /dev/null
+++ b/src/vnet/ip/ip_psh_cksum.h
@@ -0,0 +1,54 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2021 Cisco Systems, Inc.
+ */
+
+#ifndef included_ip_psh_cksum_h
+#define included_ip_psh_cksum_h
+
+#include <vnet/ip/ip.h>
+
+typedef struct _ip4_psh
+{
+  ip4_address_t src;
+  ip4_address_t dst;
+  u8 zero;
+  u8 proto;
+  u16 l4len;
+} ip4_psh_t;
+
+typedef struct _ip6_psh
+{
+  ip6_address_t src;
+  ip6_address_t dst;
+  u32 l4len;
+  u32 proto;
+} ip6_psh_t;
+
+STATIC_ASSERT (sizeof (ip4_psh_t) == 12, "ipv4 pseudo header is 12B");
+STATIC_ASSERT (sizeof (ip6_psh_t) == 40, "ipv6 pseudo header is 40B");
+
+static_always_inline u16
+ip4_pseudo_header_cksum (ip4_header_t *ip4)
+{
+  ip4_psh_t psh = { 0 };
+  psh.src = ip4->src_address;
+  psh.dst = ip4->dst_address;
+  psh.proto = ip4->protocol;
+  psh.l4len = clib_host_to_net_u16 (clib_net_to_host_u16 (ip4->length) -
+				    sizeof (ip4_header_t));
+  return ~clib_net_to_host_u16 (ip_csum (&psh, sizeof (ip4_psh_t)));
+}
+
+static_always_inline u16
+ip6_pseudo_header_cksum (ip6_header_t *ip6)
+{
+  ip6_psh_t psh = { 0 };
+  psh.src = ip6->src_address;
+  psh.dst = ip6->dst_address;
+  psh.l4len = ip6->payload_length;
+  psh.proto = clib_host_to_net_u32 ((u32) ip6->protocol);
+  return ~clib_net_to_host_u16 (ip_csum (&psh, sizeof (ip6_psh_t)));
+}
+
+#endif /* included_ip_psh_cksum_h */