src/protocols/eth.h

   1 //--------------------------------------------------------------------------
   2 // Copyright (C) 2014-2023 Cisco and/or its affiliates. All rights reserved.
   3 //
   4 // This program is free software; you can redistribute it and/or modify it
   5 // under the terms of the GNU General Public License Version 2 as published
   6 // by the Free Software Foundation.  You may not use, modify or distribute
   7 // this program under any other version of the GNU General Public License.
   8 //
   9 // This program is distributed in the hope that it will be useful, but
  10 // WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 // General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License along
  15 // with this program; if not, write to the Free Software Foundation, Inc.,
  16 // 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17 //--------------------------------------------------------------------------
  18 // eth.h author Josh Rosenbaum <jrosenba@cisco.com>
  19
  20 #ifndef PROTOCOLS_ETH_H
  21 #define PROTOCOLS_ETH_H
  22
  23 #include <string>
  24
  25 #include <arpa/inet.h>
  26 #include "protocols/protocol_ids.h"
  27
  28 #define ETHERNET_HEADER_LEN 14
  29 #define ETHERNET_MTU        1500
  30
  31 namespace snort
  32 {
  33 namespace eth
  34 {
  35 constexpr uint16_t MTU_LEN = 1500;
  36 constexpr uint16_t MAX_FRAME_LENGTH = 1500;
  37 constexpr uint16_t ETH_HEADER_LEN = 14;
  38
  39 struct EtherHdr
  40 {
  41     uint8_t ether_dst[6];
  42     uint8_t ether_src[6];
  43     uint16_t ether_type;
  44
  45     /* return data in host byte order */
  46     inline ProtocolId ethertype() const
  47     { return (ProtocolId)ntohs(ether_type); }
  48
  49     /* return data in network order */
  50     inline uint16_t raw_ethertype() const
  51     { return ether_type; }
  52
  53     // <Src MAC> -> <Dst Mac> <Ether Type>
  54     std::string to_string() const
  55     {
  56         char str[50];
  57
  58         snprintf(str, sizeof(str),
  59             "%02X:%02X:%02X:%02X:%02X:%02X -> %02X:%02X:%02X:%02X:%02X:%02X %04X",
  60             ether_src[0], ether_src[1], ether_src[2],
  61             ether_src[3], ether_src[4], ether_src[5],
  62             ether_dst[0], ether_dst[1], ether_dst[2],
  63             ether_dst[3], ether_dst[4], ether_dst[5],
  64             (uint16_t)ethertype());
  65
  66         return str;
  67     }
  68 };
  69 } // namespace eth
  70 } // namespace snort
  71
  72 #endif
  73