cnat: Destination based NAT

Type: feature

Signed-off-by: Neale Ranns <nranns@cisco.com>
Change-Id: I64a99a4fbc674212944247793fd5c1fb701408cb

1 files changed, 74 insertions, 0 deletions

diff --git a/src/plugins/cnat/cnat_snat.h b/src/plugins/cnat/cnat_snat.h
new file mode 100644
index 00000000000..97bad8b01d0
--- /dev/null
+++ b/src/plugins/cnat/cnat_snat.h
@@ -0,0 +1,74 @@
+/*
+ * 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.
+ */
+
+#ifndef __CNAT_SNAT_H__
+#define __CNAT_SNAT_H__
+
+#include <cnat/cnat_types.h>
+
+always_inline int
+cnat_search_snat_prefix (ip46_address_t * addr, ip_address_family_t af)
+{
+  /* Returns 0 if addr matches any of the listed prefixes */
+  cnat_snat_pfx_table_t *table = &cnat_main.snat_pfx_table;
+  clib_bihash_kv_24_8_t kv, val;
+  int i, n_p, rv;
+  n_p = vec_len (table->meta[af].prefix_lengths_in_search_order);
+  if (AF_IP4 == af)
+    {
+      kv.key[0] = addr->ip4.as_u32;
+      kv.key[1] = 0;
+    }
+  else
+    {
+      kv.key[0] = addr->as_u64[0];
+      kv.key[1] = addr->as_u64[1];
+    }
+
+  /*
+   * start search from a mask length same length or shorter.
+   * we don't want matches longer than the mask passed
+   */
+  i = 0;
+  for (; i < n_p; i++)
+    {
+      int dst_address_length =
+	table->meta[af].prefix_lengths_in_search_order[i];
+      ip6_address_t *mask = &table->ip_masks[dst_address_length];
+
+      ASSERT (dst_address_length >= 0 && dst_address_length <= 128);
+      /* As lengths are decreasing, masks are increasingly specific. */
+      kv.key[0] &= mask->as_u64[0];
+      kv.key[1] &= mask->as_u64[1];
+      kv.key[2] = ((u64) af << 32) | dst_address_length;
+      rv = clib_bihash_search_inline_2_24_8 (&table->ip_hash, &kv, &val);
+      if (rv == 0)
+	return 0;
+    }
+  return -1;
+}
+
+extern int cnat_add_snat_prefix (ip_prefix_t * pfx);
+extern int cnat_del_snat_prefix (ip_prefix_t * pfx);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
+
+#endif