简单RTP发送类c++实现

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简单RTP发送类c++实现
我之前编译了jrtplib 3.9.1，并且在项目中使用，结果发现在用这个库时，程序体积有增加了300多K，感觉实在是有点笨重，我无法就是用来发送rtp包而已。想想还是自己重新实现一个简单的类用用拉倒了，所以有了下面的代码。

头文件：
[cpp] view plain copy

/*!

@brief 简单rtp库

@file easy_rtp.h

*/

#ifndef _EASY_RTP_H

#define _EASY_RTP_H



#include <string>



#include <stdint.h>



#ifdef _WIN32

#include <winsock2.h>

#else

#include <netinet/in.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <errno.h>

#ifndef INVALID_SOCKET

#define INVALID_SOCKET  (SOCKET)(~0)

#endif

#ifndef SOCKET_ERROR

#define SOCKET_ERROR    (-1)

#endif

#ifndef closesocket

#define closesocket(x)  close(x)

#endif

typedef int SOCKET;

#endif



// 默认最大包大小(MTU 1500 - IP头 20 - UDP头 8)

#define DEFAULT_MAX_PACKET_SIZE 1472



/*!

@brief 简单rtp数据包装发送库

*/

class EasyRtp

{

public:

    /*!

    @brief 构造

    @param destIp 目标ip地址

    @param port 目标端口

    @param localport 本地帮定端口,默认端口采用随机值

    */

    EasyRtp(const std::string& destIp, uint16_t port, uint16_t localPort = 0, int16_t maxpacketsize = DEFAULT_MAX_PACKET_SIZE);

    /*!

    @brief 构造

    @param destIp 目标ip地址

    @param port 目标端口

    @param localport 本地帮定端口,默认端口采用随机值

    */

    EasyRtp(uint32_t destIp, uint16_t port, uint16_t localPort = 0, int16_t maxpacketsize = DEFAULT_MAX_PACKET_SIZE);

    ~EasyRtp();

public:

    /*!

    @brief 发送rtp包给目标

    @param buf 发送的缓冲

    @param len 发送的缓冲大小

    @param pt 负载类型

    @param mark 标记位

    @param timestampInc 时间戳增量

    @param 错误为-1

    */

    int32_t sendPacket(const char* buf, int32_t len, int8_t pt, bool mark, int32_t timestampInc);

private:

    /// 简单rtp头12字节,不含扩展头,csrc列表等信息

    typedef struct

    {

        uint8_t ver;                /// 版本号(2bit)

        bool p;                     /// 填充位,一直置0(1bit)

        bool x;                     /// 扩充头位,一直置0(1bit)

        uint8_t cc;                 /// csrc列表数量,一直置0(4bit)

        bool mark;                  /// 标记位(1bit)

        int8_t pt;                  /// 负载类型(7bit)

        uint16_t sn;                /// 序列号(16bit)

        uint32_t ts;                /// 时间戳(32bit)

        uint32_t ssrc;              /// 来源标示(32bit)

    }RtpHeader;



    // 最大包大小

    int16_t _maxPacketSize;

    // 发送的缓冲

    char* _sbuf;

    // 序列号

    uint16_t _sn;

    // 时间戳

    uint32_t _ts;

    // 源标示

    uint32_t _ssrc;

    // 句柄

    SOCKET _socket;

    // 目标地址

    struct sockaddr_in _destTo;

};



#endif  // _EASY_RTP_H
cpp源码：
[cpp] view plain copy

#include <stdio.h>

#include <string.h>



#include <stdexcept>



#include "easy_rtp.h"

#include "byte_write.h"

#include "utils.h"



// 默认的rtp版本

#define RTP_VERSION         2

// rtp头大小

#define RTP_HEADER_SIZE     12



EasyRtp::EasyRtp( const std::string& destIp, uint16_t port, uint16_t localPort /*= 0*/, int16_t maxpacketsize /*= 1500*/ )

    :_maxPacketSize(maxpacketsize),

    _sbuf(NULL),

    _sn(Utils::createRandam32()),

    _ts(Utils::createRandam32()),

    _ssrc(Utils::createRandam32())

{

    if (maxpacketsize >= RTP_HEADER_SIZE)

        _sbuf = new char[maxpacketsize];

    else

        throw std::runtime_error("[EasyRtp] too small packet size, must more than 12 Byte");



    _socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);

    if (_socket == INVALID_SOCKET)

        throw std::runtime_error("[EasyRtp] invalid socket");



    _destTo.sin_family = AF_INET;

    _destTo.sin_port = htons(port);

    _destTo.sin_addr.s_addr = inet_addr(destIp.c_str());



    if (localPort != 0)

    {

        struct sockaddr_in sockAddr;

        sockAddr.sin_family = AF_INET;

        sockAddr.sin_port = htons(localPort);

        sockAddr.sin_addr.s_addr = INADDR_ANY;



        if (bind(_socket, (const sockaddr*)&sockAddr, sizeof(sockAddr)) == SOCKET_ERROR)

        {

#ifndef NPRINT

#ifdef _WIN32

            printf("[EasyRtp] bind error: %d ", WSAGetLastError());

#else

            printf("[EasyRtp] bind error: %d ", errno);

#endif

#endif

            closesocket(_socket);

            throw std::runtime_error("[EasyRtp] bind error");

        }

    }

}



EasyRtp::EasyRtp( uint32_t destIp, uint16_t port, uint16_t localPort /*= 0*/, int16_t maxpacketsize /*= DEFAULT_MAX_PACKET_SIZE*/ )

    :_maxPacketSize(maxpacketsize),

    _sbuf(NULL),

    _sn(Utils::createRandam32()),

    _ts(Utils::createRandam32()),

    _ssrc(Utils::createRandam32())

{

    if (maxpacketsize >= RTP_HEADER_SIZE)

        _sbuf = new char[maxpacketsize];

    else

        throw std::runtime_error("[EasyRtp] too small packet size, must more than 12 Byte");



    _socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);

    if (_socket == INVALID_SOCKET)

        throw std::runtime_error("[EasyRtp] invalid socket");



    _destTo.sin_family = AF_INET;

    _destTo.sin_port = htons(port);

    _destTo.sin_addr.s_addr = htonl(destIp);



    if (localPort != 0)

    {

        struct sockaddr_in sockAddr;

        sockAddr.sin_family = AF_INET;

        sockAddr.sin_port = htons(localPort);

        sockAddr.sin_addr.s_addr = INADDR_ANY;



        if (bind(_socket, (const sockaddr*)&sockAddr, sizeof(sockAddr)) == SOCKET_ERROR)

        {

#ifndef NPRINT

#ifdef _WIN32

            printf("[EasyRtp] bind error: %d ", WSAGetLastError());

#else

            printf("[EasyRtp] bind error: %d ", errno);

#endif

#endif

            closesocket(_socket);

            throw std::runtime_error("[EasyRtp] bind error");

        }

    }

}



EasyRtp::~EasyRtp()

{

    if (_socket != INVALID_SOCKET)

        closesocket(_socket);

    if (_sbuf != NULL)

        delete [] _sbuf;

}



int32_t EasyRtp::sendPacket( const char* buf, int32_t len, int8_t pt, bool mark, int32_t timestampInc )

{

    if ((len + RTP_HEADER_SIZE) > _maxPacketSize)

        return -1;



    ++_sn;

    _ts += timestampInc;



    // 只设置版本号,其它的全是默认0

    _sbuf[0] = 0;

    _sbuf[0] |= RTP_VERSION << 6;

    _sbuf[1] = 0;

    _sbuf[1] |= mark << 7;

    _sbuf[1] |= pt;

    write_be_w(_sbuf + 2, _sn);

    write_be_dw(_sbuf + 4, _ts);

    write_be_dw(_sbuf + 8, _ssrc);

    // 保存数据

    memcpy(_sbuf + RTP_HEADER_SIZE, buf, len);

    int32_t ret = sendto(_socket, (const char*)_sbuf, len + RTP_HEADER_SIZE, 0, (const sockaddr*)&_destTo, sizeof(_destTo));

#ifndef NPRINT

    if (ret < 0)

    {

#ifdef _WIN32

        printf("[EasyRtp] sendto error: %d ", WSAGetLastError());

#else

        printf("[EasyRtp] sendto error: %d ", errno);

#endif

    }

#endif

    return ret;

}
注：

stdint.h是新c++标准中的头文件，定义了int32_t int8_t等typedef 类型。
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原文地址：https://www.cnblogs.com/lidabo/p/4245447.html