1 files changed, 95 insertions, 0 deletions
diff --git a/hicn-plugin/src/host_stack/utils.h b/hicn-plugin/src/host_stack/utils.h
new file mode 100644
index 000000000..67568d568
--- /dev/null
+++ b/hicn-plugin/src/host_stack/utils.h
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* Compute TCP checksum in software when offloading is disabled for a connection */
+
+#ifndef __HICN_HS_UTILS_H__
+#define __HICN_HS_UTILS_H__
+
+#include <vnet/ip/ip4.h>
+#include <vnet/ip/ip6.h>
+#include <vnet/tcp/tcp.h>
+
+always_inline u16
+ip6_tcp_compute_checksum_custom (vlib_main_t * vm, vlib_buffer_t * p0,
+				 ip46_address_t * src, ip46_address_t * dst)
+{
+  ip_csum_t sum0;
+  u16 payload_length_host_byte_order;
+  u32 i;
+
+  /* Initialize checksum with ip header. */
+  sum0 = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, p0)) +
+    clib_host_to_net_u16 (IP_PROTOCOL_TCP);
+  payload_length_host_byte_order = vlib_buffer_length_in_chain (vm, p0);
+
+  for (i = 0; i < ARRAY_LEN (src->ip6.as_uword); i++)
+    {
+      sum0 = ip_csum_with_carry
+	(sum0, clib_mem_unaligned (&src->ip6.as_uword[i], uword));
+      sum0 = ip_csum_with_carry
+	(sum0, clib_mem_unaligned (&dst->ip6.as_uword[i], uword));
+    }
+
+  return ip_calculate_l4_checksum (vm, p0, sum0,
+				   payload_length_host_byte_order, NULL, 0,
+				   NULL);
+}
+
+always_inline u16
+ip4_tcp_compute_checksum_custom (vlib_main_t * vm, vlib_buffer_t * p0,
+				 ip46_address_t * src, ip46_address_t * dst)
+{
+  ip_csum_t sum0;
+  u32 payload_length_host_byte_order;
+
+  payload_length_host_byte_order = vlib_buffer_length_in_chain (vm, p0);
+  sum0 =
+    clib_host_to_net_u32 (payload_length_host_byte_order +
+			  (IP_PROTOCOL_TCP << 16));
+
+  sum0 = ip_csum_with_carry (sum0, clib_mem_unaligned (&src->ip4, u32));
+  sum0 = ip_csum_with_carry (sum0, clib_mem_unaligned (&dst->ip4, u32));
+
+  return ip_calculate_l4_checksum (vm, p0, sum0,
+				   payload_length_host_byte_order, NULL, 0,
+				   NULL);
+}
+
+always_inline u16
+hicn_hs_compute_checksum (hicn_hs_ctx_t * ctx, vlib_buffer_t * b)
+{
+  u16 checksum = 0;
+  if (PREDICT_FALSE (ctx->cfg_flags & HICN_HS_CFG_F_NO_CSUM_OFFLOAD))
+    {
+      hicn_hs_worker_t *wrk = hicn_hs_get_worker_by_context (ctx);
+      vlib_main_t *vm = wrk->vm;
+      ip46_address_t local_ip = {0};
+
+      if (ctx->c_is_ip4)
+	checksum = ip4_tcp_compute_checksum_custom
+	  (vm, b, &local_ip, &ctx->c_rmt_ip);
+      else
+	checksum = ip6_tcp_compute_checksum_custom
+	  (vm, b, &local_ip, &ctx->c_rmt_ip);
+    }
+  else
+    {
+      b->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
+    }
+  return checksum;
+}
+
+#endif /* __HICN_HS_UTILS_H__ */