Merge commit '86cc97e55fe346502462284d2e636a2b3708163e' as 'Sources/OpenVPN3'

Sources/OpenVPN3/openvpn/ip/ip4.hpp

@@ -0,0 +1,68 @@
+//    OpenVPN -- An application to securely tunnel IP networks
+//               over a single port, with support for SSL/TLS-based
+//               session authentication and key exchange,
+//               packet encryption, packet authentication, and
+//               packet compression.
+//
+//    Copyright (C) 2012-2017 OpenVPN Inc.
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Affero General Public License Version 3
+//    as published by the Free Software Foundation.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Affero General Public License for more details.
+//
+//    You should have received a copy of the GNU Affero General Public License
+//    along with this program in the COPYING file.
+//    If not, see <http://www.gnu.org/licenses/>.
+
+// IPv4 header
+
+#pragma once
+
+#include <cstdint> // for std::uint32_t, uint16_t, uint8_t
+
+#pragma pack(push)
+#pragma pack(1)
+
+namespace openvpn {
+
+  struct IPv4Header
+  {
+    static unsigned int length(const std::uint8_t version_len)
+    {
+      return (version_len & 0x0F) << 2;
+    }
+
+    static std::uint8_t ver_len(const unsigned int version,
+				const unsigned int len)
+    {
+      return ((len >> 2) & 0x0F) | (version & 0x0F) << 4;
+    }
+
+    std::uint8_t    version_len;
+
+    std::uint8_t    tos;
+    std::uint16_t   tot_len;
+    std::uint16_t   id;
+
+    enum {
+      OFFMASK=0x1fff,
+    };
+    std::uint16_t   frag_off;
+
+    std::uint8_t    ttl;
+
+    std::uint8_t    protocol;
+
+    std::uint16_t   check;
+    std::uint32_t   saddr;
+    std::uint32_t   daddr;
+    /* The options start here. */
+  };
+}
+
+#pragma pack(pop)