1 files changed, 124 insertions, 0 deletions
diff --git a/src/plugins/npt66/npt66.c b/src/plugins/npt66/npt66.c
new file mode 100644
index 00000000000..277fce496fc
--- /dev/null
+++ b/src/plugins/npt66/npt66.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright(c) 2023 Cisco Systems, Inc.
+
+/*
+ * npt66.c: NPT66 plugin
+ * An implementation of Network Prefix Translation for IPv6-to-IPv6 (NPTv6) as
+ * specified in RFC6296.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <vlib/vlib.h>
+#include <vnet/feature/feature.h>
+#include <vppinfra/pool.h>
+#include "npt66.h"
+
+static int
+npt66_feature_enable_disable (u32 sw_if_index, bool is_add)
+{
+  if (vnet_feature_enable_disable ("ip6-unicast", "npt66-input", sw_if_index,
+				   is_add, 0, 0) != 0)
+    return -1;
+  if (vnet_feature_enable_disable ("ip6-output", "npt66-output", sw_if_index,
+				   is_add, 0, 0) != 0)
+    return -1;
+  return 0;
+}
+
+static void
+ipv6_prefix_zero (ip6_address_t *address, int prefix_len)
+{
+  int byte_index = prefix_len / 8;
+  int bit_offset = prefix_len % 8;
+  uint8_t mask = (1 << (8 - bit_offset)) - 1;
+  if (byte_index < 16)
+    {
+      address->as_u8[byte_index] &= mask;
+      for (int i = byte_index + 1; i < 16; i++)
+	{
+	  address->as_u8[i] = 0;
+	}
+    }
+}
+
+int
+npt66_binding_add_del (u32 sw_if_index, ip6_address_t *internal,
+		       int internal_plen, ip6_address_t *external,
+		       int external_plen, bool is_add)
+{
+  npt66_main_t *nm = &npt66_main;
+  int rv = 0;
+
+  /* Currently limited to a single binding per interface */
+  npt66_binding_t *b = npt66_interface_by_sw_if_index (sw_if_index);
+
+  if (is_add)
+    {
+      bool configure_feature = false;
+      /* Ensure prefix lengths are less than or equal to a /64 */
+      if (internal_plen > 64 || external_plen > 64)
+	return VNET_API_ERROR_INVALID_VALUE;
+
+      /* Create a binding entry (or update existing) */
+      if (!b)
+	{
+	  pool_get_zero (nm->bindings, b);
+	  configure_feature = true;
+	}
+      b->internal = *internal;
+      b->internal_plen = internal_plen;
+      b->external = *external;
+      b->external_plen = external_plen;
+      b->sw_if_index = sw_if_index;
+
+      ipv6_prefix_zero (&b->internal, internal_plen);
+      ipv6_prefix_zero (&b->external, external_plen);
+      vec_validate_init_empty (nm->interface_by_sw_if_index, sw_if_index, ~0);
+      nm->interface_by_sw_if_index[sw_if_index] = b - nm->bindings;
+
+      uword delta = 0;
+      delta = ip_csum_add_even (delta, b->external.as_u64[0]);
+      delta = ip_csum_add_even (delta, b->external.as_u64[1]);
+      delta = ip_csum_sub_even (delta, b->internal.as_u64[0]);
+      delta = ip_csum_sub_even (delta, b->internal.as_u64[1]);
+      delta = ip_csum_fold (delta);
+      b->delta = delta;
+
+      if (configure_feature)
+	rv = npt66_feature_enable_disable (sw_if_index, is_add);
+    }
+  else
+    {
+      /* Delete a binding entry */
+      npt66_binding_t *b = npt66_interface_by_sw_if_index (sw_if_index);
+      if (!b)
+	return VNET_API_ERROR_NO_SUCH_ENTRY;
+      nm->interface_by_sw_if_index[sw_if_index] = ~0;
+      pool_put (nm->bindings, b);
+      rv = npt66_feature_enable_disable (sw_if_index, is_add);
+    }
+
+  return rv;
+}
+
+/*
+ * Do a lookup in the interface vector (interface_by_sw_if_index)
+ * and return pool entry.
+ */
+npt66_binding_t *
+npt66_interface_by_sw_if_index (u32 sw_if_index)
+{
+  npt66_main_t *nm = &npt66_main;
+
+  if (!nm->interface_by_sw_if_index ||
+      sw_if_index > (vec_len (nm->interface_by_sw_if_index) - 1))
+    return 0;
+  u32 index = nm->interface_by_sw_if_index[sw_if_index];
+  if (index == ~0)
+    return 0;
+  if (pool_is_free_index (nm->bindings, index))
+    return 0;
+  return pool_elt_at_index (nm->bindings, index);
+}