client.c

linux 环境下的socket编程客户端

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>

#define TCP_BUFFER_SIZE   0X10000
#define PACKET_SIZE       4096
#define STRLEN            0x100


int main()
{
  int sockfd;
  char buffer[PACKET_SIZE];
  struct sockaddr_in svr_addr, client_addr;
  struct hostent *host;
  int port, nbytes;
  int seq = 0;
  unsigned int i, iret;
  unsigned short datalen, offsetd;
  unsigned char  offsets, bytes;
  unsigned char tmpbuf[STRLEN];
  int buffer_size, opt;

  if((sockfd = socket(AF_INET, SOCK_STREAM,0)) == -1)
  {
    fprintf(stderr, "socket error :%s\a\n", strerror(errno));
    exit(1);
  }

  bzero(&client_addr, sizeof(client_addr));
  client_addr.sin_family=AF_INET;
  client_addr.sin_port=htons(0);
  client_addr.sin_addr.s_addr=htonl(INADDR_ANY);
  if (bind(sockfd, (struct sockaddr*)(&client_addr), sizeof(struct sockaddr)) == -1)
  {
    fprintf(stderr, "Bind address error\n");
    exit(1);
  }

  bzero(&svr_addr, sizeof(svr_addr));
  svr_addr.sin_family=AF_INET;
  svr_addr.sin_port=htons(5986);
  svr_addr.sin_addr.s_addr= inet_addr("192.168.12.79");

  if(connect(sockfd, (struct sockaddr*)(&svr_addr), sizeof(struct sockaddr)) == -1)
  {
   fprintf(stderr, "connect error:%s\n", strerror(errno));
   exit(1);
  }
  
  fprintf(stderr, "connect success\n");
  opt = 1;
  buffer_size = TCP_BUFFER_SIZE;
  if ((setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, &buffer_size, sizeof(opt)) != 0) 
     ||(setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &buffer_size, sizeof(opt)) != 0))
  {
    fprintf(stderr, "setsockopt error:%s\n", strerror(errno));
    exit(1);
  }

  for(i=0;i<=STRLEN;i++)
  {  tmpbuf[i] = i;}
  datalen = 100;
  offsetd = 0;
  offsets = 0;
  
  while (1)
  {
    if (datalen >= STRLEN) {  datalen = 100;}
    if (datalen+offsetd+3 >= PACKET_SIZE)
    {
      iret = send(sockfd, buffer, offsetd, 0);
      fprintf(stderr, "send datalen = %d\n", iret);
      offsetd = 0;
    }
    
    buffer[offsetd] = (datalen+3) & 0xff;
    buffer[offsetd+1] = ((datalen+3)>>8) & 0xff;
    buffer[offsetd+2] = 0x04;
    offsetd += 3;

    bytes = STRLEN - offsets;
    if (bytes >= datalen)
    {
      memcpy(buffer+offsetd, tmpbuf+offsets, datalen);
    }
    else
    {
      memcpy(buffer+offsetd, tmpbuf+offsets, bytes);
      memcpy(buffer+offsetd+bytes, tmpbuf, datalen-bytes);
    }
    offsetd += datalen;
    offsets += datalen;
    datalen++;
    //usleep(100);
  }//while
  
  close(sockfd);
  return 0;
}