IPIP: Add IP{v4,v6} over IP{v4,v6} configured tunnel support.

Change-Id: I166301c9e2388bae5f70ec0179d663a2703e27f5
Signed-off-by: Ole Troan <ot@cisco.com>
diff --git a/src/vnet/ipip/sixrd.h b/src/vnet/ipip/sixrd.h
new file mode 100644
index 0000000..f107d5e
--- /dev/null
+++ b/src/vnet/ipip/sixrd.h
@@ -0,0 +1,72 @@
+/*---------------------------------------------------------------------------
+ * Copyright (c) 2009-2014 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.
+ *---------------------------------------------------------------------------
+ */
+#include <stdbool.h>
+#include <vnet/fib/ip6_fib.h>
+#include <vnet/ip/ip.h>
+#include <vnet/ipip/ipip.h>
+#include <vnet/vnet.h>
+#include <vppinfra/error.h>
+
+#define SIXRD_DEFAULT_MTU 1480	/* 1500 - IPv4 header */
+
+#define foreach_sixrd_error                                                    \
+  /* Must be first. */                                                         \
+  _(NONE, "valid SIXRD packets")                                               \
+  _(BAD_PROTOCOL, "bad protocol")                                              \
+  _(SEC_CHECK, "security check failed")                                        \
+  _(NO_TUNNEL, "no tunnel")
+
+
+typedef enum
+{
+#define _(sym, str) SIXRD_ERROR_##sym,
+  foreach_sixrd_error
+#undef _
+    SIXRD_N_ERROR,
+} sixrd_error_t;
+
+extern sixrd_main_t sixrd_main;
+
+static_always_inline sixrd_tunnel_t *
+find_tunnel_by_ip4_address (ip4_address_t * ip)
+{
+  sixrd_main_t *sm = &sixrd_main;
+  uword *p;
+  p = hash_get (sm->tunnel_by_ip, ip->as_u32);
+  if (!p)
+    return NULL;
+  return pool_elt_at_index (sm->tunnels, p[0]);
+}
+
+static_always_inline sixrd_tunnel_t *
+ip4_sixrd_get_tunnel (u32 sdi, ip4_address_t * addr, u8 * error)
+{
+  sixrd_tunnel_t *t = find_tunnel_by_ip4_address (addr);
+  if (!t)
+    {
+      *error = SIXRD_ERROR_NO_TUNNEL;
+      return NULL;
+    }
+  return t;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */