Socket Client demo

#include <stdio.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <string.h>#include <stdlib.h>#include <string>#include <iostream>#include <errno.h>#include <unistd.h>#include <sys/types.h>#include <time.h>#include <netinet/tcp.h>void client(int fd,std::string server_ip,short server_port,double bandwidth);int send_block(int fd,const char *buf,size_t buf_len);int main(int n,char *arg[]){    if(4!=n)    {        fprintf(stderr,"usage: ./client + server ip + port + bandwidth\n");        return -1;    }    std::string server_ip=std::string(arg[1]);    short server_port=static_cast<short>(atoi(arg[2]));    double bandwidth=atof(arg[3]);    int client_sockfd;    if(-1!=(client_sockfd=socket(AF_INET,SOCK_STREAM,0)))    {        client(client_sockfd,server_ip,server_port,bandwidth);        close(client_sockfd);    }    else    {        fprintf(stderr,"%s\n",strerror(errno));        return -1;    }    return 0;}void client(int fd,std::string server_ip,short server_port,double bandwidth){    int no_delay=1;    if(-1==setsockopt(fd,IPPROTO_TCP,TCP_NODELAY,(const char *)&no_delay,sizeof(int)))    {        fprintf(stderr,"%s\n",strerror(errno));        return;    }    int send_buf=1024*32;    if(-1==setsockopt(fd,SOL_SOCKET,SO_SNDBUF,(const char *)&send_buf,sizeof(int)))    {        fprintf(stderr,"%s\n",strerror(errno));        return;    }    struct sockaddr_in server_addr;    memset(&server_addr,0,sizeof(struct sockaddr_in));    server_addr.sin_family=AF_INET;    server_addr.sin_addr.s_addr=inet_addr(server_ip.c_str());    server_addr.sin_port=htons(server_port);    if(-1==connect(fd,(const sockaddr *)&server_addr,sizeof(struct sockaddr)))    {        fprintf(stderr,"%s\n",strerror(errno));        return;    }    std::string data;    data+="RTSP/1.0 200 OK\r\n";    data+="CSeq: 312\r\n";    data+="Date: 23 Jan 1997 15:35:06 GMT\r\n";    data+="Content-Type: application/sdp\r\n";    data+="Content-Length: 365\r\n\r\n";    data+="v=0\r\n";    data+="o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4\r\n";    data+="s=SDP Seminar\r\n";    data+="i=A Seminar on the session description protocol\r\n";    data+="u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps\r\n";    data+="e=mjh@isi.edu (Mark Handley)\r\n";    data+="c=IN IP4 224.2.17.12/127\r\n";    data+="t=2873397496 2873404696\r\n";    data+="a=recvonly\r\n";    data+="m=audio 3456 RTP/AVP 0\r\n";    data+="m=video 2232 RTP/AVP 31\r\n";    data+="m=whiteboard 32416 UDP WB\r\n";    data+="a=orient:portrait\r\n\r\n";    //adjust data size    for(int i=0;i<4;++i)    {        data+=data;    }    const int send_num=1200;    unsigned int send_bytes=0;    int r;    double rate;    unsigned int start_time=clock();    for(int i=0;i<send_num;++i)    {        if(-1==(r=send_block(fd,data.c_str(),data.size())))        {            break;        }        else        {            send_bytes+=r;            rate=send_bytes*1.0/((clock()-start_time)*1.0/CLOCKS_PER_SEC);            while(rate>bandwidth*1024*1024)            {                rate=send_bytes*1.0/((clock()-start_time)*1.0/CLOCKS_PER_SEC);            }        }    }    unsigned int end_time=clock();    unsigned int time_elapse=end_time-start_time;    std::cerr<<"data size= "<<data.size()<<" bytes"<<std::endl;    std::cerr<<"total= "<<data.size()*send_num<<" bytes"<<std::endl;    std::cerr<<"send= "<<send_bytes<<" bytes"<<std::endl;    std::cerr<<"elapse= "<<(time_elapse*1.0/CLOCKS_PER_SEC)<<" s"<<std::endl;    std::cerr<<"rate= "<<send_bytes*1.0/1024/(time_elapse*1.0/CLOCKS_PER_SEC)<<" KBps"<<std::endl;}int send_block(int fd,const char *buf,size_t buf_len){    if(buf_len<=0)    {        return -1;    }    unsigned int index=0;    unsigned int send_len=0;    int r;    while(send_len<buf_len)    {        if(-1==(r=send(fd,buf+index,buf_len-send_len,0)))        {            if(errno==EAGAIN || errno==EWOULDBLOCK || errno==EINTR)            {                continue;            }            else            {                fprintf(stderr,"%s\n",strerror(errno));                return -1;            }        }        else        {            index+=r;            send_len+=r;        }    }    return send_len;}