net_tools.hpp

#pragma once
//=====================================================================//
/*!	@file
	@brief	ネットワーク・ツール
    @author 平松邦仁 (hira@rvf-rc45.net)
	@copyright	Copyright (C) 2017 Kunihito Hiramatsu @n
				Released under the MIT license @n
				https://github.com/hirakuni45/RX/blob/master/LICENSE
*/
//=====================================================================//
#include <cstdint>
#include <cstring>
#include <random>
#include "common/byte_order.h"
#include "common/time.h"

#if defined(BIG_ENDIAN)
#elif defined(LITTLE_ENDIAN)
#else
#error "net_tools.hpp requires BIG_ENDIAN or LITTLE_ENDIAN be defined."
#endif

extern "C" {
	time_t get_time();
}

namespace net {

	//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++//
	/*!
		@brief  ネット・ツール
	*/
	//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++//
	struct tools {

		//-----------------------------------------------------------------//
		/*!
			@brief  16 ビット列変換
			@param[in]	data	変換元
			@return 変換後
		*/
		//-----------------------------------------------------------------//
		static inline uint16_t htons(uint16_t data)
		{
#ifdef LITTLE_ENDIAN
			uint16_t tmp = 0;
			tmp  = (data & 0x00ff) << 8;
			tmp |= (data & 0xff00) >> 8;
			return tmp;
#else
			return data;
#endif
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  32 ビット列変換
			@param[in]	data	変換元
			@return 変換後
		*/
		//-----------------------------------------------------------------//
		static inline uint32_t htonl(uint32_t data)
		{
#ifdef LITTLE_ENDIAN
			uint32_t tmp = 0;
			tmp  = (data & 0x000000ff) << 24;
			tmp |= (data & 0x0000ff00) << 8;
			tmp |= (data & 0x00ff0000) >> 8;
			tmp |= (data & 0xff000000) >> 24;
			return tmp;
#else
   			return data;
#endif
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  イーサーネット・チェック・サムの計算
			@param[in]	src	ソース
			@param[in]	len	バイト数
			@param[in]	sumorg	サム初期値（通常「０」）
			@return チェック・サム
		*/
		//-----------------------------------------------------------------//
		static uint16_t calc_sum(const void* src, uint16_t len, uint16_t sumorg = 0)
		{
			const uint8_t* d = static_cast<const uint8_t*>(src);
			uint32_t sum = sumorg;
			bool mod = false;
			if(len & 1) {
				len &= 0xfffe;
				mod = true;
			}
			for(uint16_t i = 0; i < len; i += 2) {
				sum += (d[0] << 8) | d[1];
				d += 2;
			}
			if(mod) {
				sum += d[0] << 8;
			}
			return ~((sum & 0xffff) + (sum >> 16));
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  ブロード・キャスト型、MAC アドレスの検査
			@param[in]	src	ソース
			@return ブロード・キャスト型なら「true」
		*/
		//-----------------------------------------------------------------//
		static const uint8_t* get_brodcast_mac()
		{
			static constexpr uint8_t bmac[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
			return bmac;
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  ブロード・キャスト型、MAC アドレスの検査
			@param[in]	src	ソース
			@return ブロード・キャスト型なら「true」
		*/
		//-----------------------------------------------------------------//
		static bool check_brodcast_mac(const uint8_t* top)
		{
			return std::memcmp(get_brodcast_mac(), top, 6) == 0;
		}


		//-----------------------------------------------------------------//
		/*!
			@brief	MAC アドレスが全て「０」を検査
			@param[in]	src	ソース
			@return 全て「０」なら「true」
		*/
		//-----------------------------------------------------------------//
		static bool check_allzero_mac(const uint8_t* top)
		{
			static constexpr uint8_t zero[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
			return std::memcmp(zero, top, 6) == 0;
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  MAC アドレスの文字列を取得
			@param[in]	src	ソース・アドレス
			@return 文字列
		*/
		//-----------------------------------------------------------------//
		static const char* mac_str(const uint8_t* src) {
			static char tmp[20];
			utils::sformat("%02X:%02X:%02X:%02X:%02X:%02X", tmp, sizeof(tmp))
				% static_cast<uint32_t>(src[0])
				% static_cast<uint32_t>(src[1])
				% static_cast<uint32_t>(src[2])
				% static_cast<uint32_t>(src[3])
				% static_cast<uint32_t>(src[4])
				% static_cast<uint32_t>(src[5]);
			return tmp;
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  IP アドレスの文字列を取得
			@param[in]	src	ソース・アドレス
			@return 文字列
		*/
		//-----------------------------------------------------------------//
		static const char* ip_str(const uint8_t* p) {
			static char tmp[17];
			utils::sformat("%d.%d.%d.%d", tmp, sizeof(tmp))
				% static_cast<int>(p[0])
				% static_cast<int>(p[1])
				% static_cast<int>(p[2])
				% static_cast<int>(p[3]);
			return tmp;
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  メルセンヌ・ツイスターを使った乱数生成
			@return メルセンヌ・ツイスター乱数
		*/
		//-----------------------------------------------------------------//
		static std::mt19937& at_rand_mt()
		{
			static std::mt19937 mt(static_cast<int>(get_time()));
			return mt;
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  メルセンヌ・ツイスターを使った乱数生成
			@param[in]	mask	マスク
			@return 乱数
		*/
		//-----------------------------------------------------------------//
		static uint32_t rand(uint32_t mask = 0xffffffff) {
			auto& r = at_rand_mt();
			return r() & mask;
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  接続ポート番号の生成（49152～65535）
			@return 接続ポート番号
		*/
		//-----------------------------------------------------------------//
		static uint16_t connect_port() {
///			static std::uniform_int_distribution<> rand_range(49152, 65535);
///			return rand_range(at_rand_mt());
			static uint16_t port = 49152;
			uint16_t p = port;
			++port;
			if(port < 49152) port = 49152;
			return p;
		}


		//-----------------------------------------------------------------//
		/*!
			@brief  IP フレームの CRC 計算
			@param[in]	src	ソース・アドレス
			@param[in]	len	長さ
			@return CRC (FCS)
		*/
		//-----------------------------------------------------------------//
		static uint32_t calc_crc(const void* src, uint32_t len)
		{
#ifdef FIRST_IP_CRC
			static const uint32_t crc32[256] = {
				0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
				0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
				0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
				0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
				0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
				0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
				0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
				0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
				0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
				0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
				0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
				0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
				0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
				0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
				0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
				0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
				0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
				0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
				0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
				0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
				0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
				0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
				0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
				0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
				0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
				0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
				0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
				0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
				0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
				0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
				0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
				0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
				0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
				0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
				0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
				0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
				0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
				0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
				0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
				0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
				0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
				0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
				0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
				0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
				0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
				0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
				0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
				0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
				0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
				0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
				0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
				0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
				0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
				0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
				0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
				0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
				0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
				0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
				0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
				0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
				0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
				0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
				0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
				0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
			};

			const uint8_t* p = static_cast<const uint8_t*>(src);
			uint32_t crc = 0xFFFFFFFF;
			for(uint32_t i = 0; i < len; ++i) {
				crc = (crc >> 8) ^ crc32[(crc & 0xFF) ^ p[i]];
			}

			// Return 1's complement value
			return ~crc;
#else
			//Point to the data over which to calculate the CRC
			const uint8_t* p = static_cast<const uint8_t *>(src);

			// CRC preset value
			uint32_t crc = 0xFFFFFFFF;
			for(uint32_t i = 0; i < len; ++i) {
				// Update CRC value
				crc ^= p[i];

				for(int j = 0; j < 8; ++j) {
					if(crc & 0x00000001) {
						crc = (crc >> 1) ^ 0xEDB88320;
					} else {
						crc = crc >> 1;
					}
				}
			}
			return ~crc;
#endif
		}
	};
}