C 服务器 - 打印收到的消息？

Question

我使用 netcat 向此 C 服务器发送一条消息。

echo <message> | nc <ip> <port>

它打印:

Client IP : <ip>

我希望它也打印:

Client Message : <message>

C 服务器

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <err.h>

char response[] = "hi";

int main()
{
  int one = 1, client_fd;
  struct sockaddr_in svr_addr, cli_addr;
  socklen_t sin_len = sizeof(cli_addr);

  int sock = socket(AF_INET, SOCK_STREAM, 0);
  if (sock < 0)
    err(1, "can't open socket");

  setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(int));

  int port = 85;
  svr_addr.sin_family = AF_INET;
  svr_addr.sin_addr.s_addr = INADDR_ANY;
  svr_addr.sin_port = htons(port);

  if (bind(sock, (struct sockaddr *) &svr_addr, sizeof(svr_addr)) == -1) {
    close(sock);
    err(1, "Can't bind");
  }

  listen(sock, 5);
  while (1) {
    client_fd = accept(sock, (struct sockaddr *) &cli_addr, &sin_len);
    printf("Client IP : [%s]\n", inet_ntoa(cli_addr.sin_addr));

    if (client_fd == -1) {
      perror("Can't accept");
      continue;
    }

    write(client_fd, response, sizeof(response) - 1); /*-1:'\0'*/
    close(client_fd);
  }
}

Answer 1

您只需从套接字读取数据(在accept调用之后，一旦您检查client_fd可用):

if (client_fd == -1) {
  perror("Can't accept");
  continue;
}



printf("Client Message : <");

/* buffer to store result */
char buffer[64] = "";
/* while we can read from socket */
while (read(client_fd, buffer, sizeof buffer-1) > 0)
{
    /* write what have been read */
    printf("%s", buffer);
}
puts(">");



write(client_fd, response, sizeof(response) - 1); /*-1:'\0'*/
close(client_fd);

您还可以使用 recv功能。