Linux系统编程之TCP网络编程模型

Linux TCP网络编程模型示例

客户端代码示例

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

int main(void)
{
  int sd;
  int nwrote;
  int RECV_BUF_SIZE = 2048;
  socklen_t len;
  struct sockaddr_in address;
  char buf[RECV_BUF_SIZE];

  if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    return -1;

  address.sin_family = AF_INET;
  address.sin_addr.s_addr = inet_addr("127.0.0.1");
  address.sin_port = htons(7788);

  len = sizeof(struct sockaddr_in);

  if(connect(sd, (struct sockaddr *)&address, len) < 0)
  {
    close(sd);
    fprintf(stderr, "connect faild. \r\n");
    return -2;
  }

  while (1)
  {
    printf("Please enter:");
    scanf("%s", buf);

    if (!strncmp(buf, "quit", 4))
      break;

    if ((nwrote = send(sd, buf, strlen(buf), 0)) < 0)
      break;

    fprintf(stdout, "send %d chars. \r\n", nwrote);
  }

  close(sd);
  return EXIT_SUCCESS;
}

服务器代码示例

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

int main(void)
{
  int sd, new_sd;
  int size;
  int RECV_BUF_SIZE = 2048;
  int n, nwrote;
  struct sockaddr_in address, remote;
  char recv_buf[RECV_BUF_SIZE];

  if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
  {
    fprintf(stderr, "create sock failed. \r\n");
    return -1;
  }

  address.sin_family = AF_INET;
  address.sin_port = htons(7788);
//  address.sin_addr.s_addr = htonl(INADDR_ANY);
  address.sin_addr.s_addr = inet_addr("127.0.0.1");

  if (bind(sd, (struct sockaddr *) &address, sizeof(address)) < 0)
  {
    fprintf(stderr, "bind failed. \r\n");
    close(sd);
    return -2;
  }

  listen(sd, 0);

  size = sizeof(remote);

  if ((new_sd = accept(sd, (struct sockaddr *) &remote, (socklen_t *) &size)) < 0)
  {
    fprintf(stderr, "accept failed. \r\n");
    close(sd);
    return -3;
  }

  while (1)
  {
    if ((n = recv(new_sd, recv_buf, RECV_BUF_SIZE, 0)) <= 0)
      break;

    if (!strncmp(recv_buf, "quit", 4))
      break;

    if ((nwrote = send(new_sd, recv_buf, n, 0)) < 0)
      break;
  }

  close(sd);
  close(new_sd);
  return 0;
}