feat: Due to the deep modifications related to names and packet format,

this task cover a large part of the codebase and involves several changes:

- the library provides a name data structure (hicn_name_t ), which is composed
  of a name prefix (hicn_name_prefix_t) and a name suffix (hicn_name_suffix_t),
  and it has been extended to provide all support functions required for name
  manipulation, including common prefix computation, as required for the Longest
  Prefix Match (LPM)in the forwarder, in addition to Exact Prefix Match (EPM).
- all code has been rewritten to use this data structure instead of having for
  instance the forwarder define its own name class (used to be Name and NameBitVector)
  the code has been refactored to minimize name allocations and copies, one remaining
  aspect is the difference of name storage between PIT and CS entries (respectively
  in the PIT entry, and in the message buffer), which causes the packet cache
  index to be updated when a PIT entry is converted into a CS entry. By storing
  the name in the PIT/CS entry everytime, we might save on this operation).
- hicn-light FIB has been rewritten : code has been refactored and should now be
  shorter and documented; unit tests have been drafted but more would be required
  to cover all cases and match the algorithms to add/remove nodes, as specified in the doc.
  all protocol details and hICN header formats are now abstracted by the library
  for the forwarder (and thus header.h and  protocols/*.h have been removed from
  public includes, and replaced by packet.h providing protocol agnostic packet
  level functions, completely replacing the compat.h header that used to provide
  similar functions.
- this works by exposing a opaque buffer to the application (a kind of socket buffer)
  which is used by the lib to cache the packet format and offsets of the different
  layers in the buffer and provider efficient operations (the packet format is
  either defined for packet construction, or guessed at ingress, and this structure
  is updated accordingly only once).

Co-authored-by: Jordan Augé <jordan.auge+fdio@cisco.com>
Signed-off-by: Luca Muscariello <muscariello@ieee.org>
Change-Id: I31e321897f85f0267fe8ba4720363c180564492f

1 files changed, 86 insertions, 0 deletions

diff --git a/lib/src/protocol/ipv6.h b/lib/src/protocol/ipv6.h
new file mode 100644
index 000000000..9a51096a0
--- /dev/null
+++ b/lib/src/protocol/ipv6.h
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2021-2022 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 HICN_PROTOCOL_IPV6_H
+#define HICN_PROTOCOL_IPV6_H
+
+#include <hicn/util/ip_address.h>
+
+#include <hicn/common.h>
+
+/*
+ * The length of the IPV6 header struct must be 40 bytes.
+ */
+#define EXPECTED_IPV6_HDRLEN 40
+
+typedef struct
+{
+#if 0 // TEMPORARY FIX
+  union
+  {
+    struct
+    {
+#endif
+  u32 version_class_flow; /* version, traffic class and 20 bits of flow-ID */
+  u16 len;		  /* payload length */
+  u8 nxt;		  /* next header */
+  u8 hlim;		  /* hop limit */
+#if 0
+    };
+    u8 vfc;			/* 4 bits version, top 4 bits class */
+  };
+#endif
+  ipv6_address_t saddr; /* source address */
+  ipv6_address_t daddr; /* destination address */
+} _ipv6_header_t;
+
+#define IPV6_HDRLEN sizeof (_ipv6_header_t)
+static_assert (EXPECTED_IPV6_HDRLEN == IPV6_HDRLEN,
+	       "Size of IPV6 struct does not match its expected size.");
+
+/*
+ * The length of the IPV6 pseudo header struct must be 40 bytes.
+ */
+#define EXPECTED_IPV6_PSHDRLEN 40
+
+typedef struct
+{
+  ipv6_address_t ip_src;
+  ipv6_address_t ip_dst;
+  u32 size;
+  u16 zeros;
+  u8 zero;
+  u8 protocol;
+} ipv6_pseudo_header_t;
+
+#define IPV6_PSHDRLEN sizeof (ipv6_pseudo_header_t)
+static_assert (EXPECTED_IPV6_PSHDRLEN == IPV6_PSHDRLEN,
+	       "Size of IPV6_PSHDR struct does not match its expected size.");
+
+/* Default field values */
+#define IPV6_DEFAULT_VERSION	    6
+#define IPV6_DEFAULT_TRAFFIC_CLASS  0
+#define IPV6_DEFAULT_FLOW_LABEL	    0
+#define IPV6_DEFAULT_PAYLOAD_LENGTH 0
+
+#endif
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */