test15.c

华清远见应用培训班例程源码

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

///////////////////////////////////////////////////////////////////////////////
// definitions
///////////////////////////////////////////////////////////////////////////////
#define PORT		3345
#define BACKLOG		5

///////////////////////////////////////////////////////////////////////////////
// functions
///////////////////////////////////////////////////////////////////////////////
int main(int argc, char **argv)
{
  // int socket(int domain, int type, int protocol);

  int fd;

  // XXX: step 1, create socket.

  //if ((fd = socket(PF_INET, SOCK_RAW, 0)) < 0)
  //if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
  if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0)
  {
    fprintf(stderr, "ERROR: call socket() failed: %s\n", strerror(errno));
    // FIXME: deal with this error.
    exit(1);
  }

#ifdef _DEBUG_
  fprintf(stdout, "DEBUG: Create socket successed, new created socket = %d\n", fd);
#endif

  // XXX: step 2.5, reuse address & reuse port

  int on;

  on = 1;
  //setsockopt(listen_socket, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
  if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0)
  {
    fprintf(stderr, "ERROR: call setsockopt() failed.\n");
  }

#ifdef SO_REUSEPORT
  on = 1;
  if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on)) < 0)
  {
    // Error!
  }
#endif				// SO_REUSEPORT

  // XXX: step 2.6, gethostbyname()

  // XXX: step 2, bind

  // int bind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen);
  struct sockaddr_in address;

  memset(&address, 0, sizeof(address));
  address.sin_family = PF_INET;
  // XXX: bind to all interfaces.
  address.sin_addr.s_addr = htonl(INADDR_ANY);
  address.sin_port = htons(PORT);

  if (bind(fd, (struct sockaddr *) &address, sizeof(address)) < 0)
  {
    fprintf(stderr, "ERROR: call bind() failed: %s\n", strerror(errno));
    // FIXME: deal with this error.
    exit(1);
  }

#ifdef _DEBUG_
  fprintf(stdout, "DEBUG: call bind() successed.\n");
#endif

  // XXX: step 3, listen

  // int listen(int s, int backlog);
  if (listen(fd, BACKLOG) < 0)
  {
    fprintf(stderr, "ERROR: call bind() failed: %s\n", strerror(errno));
    // FIXME: deal with this error.
    exit(1);
  }

#ifdef _DEBUG_
  fprintf(stdout, "DEBUG: call listen() successed.\n");
#endif

  for (;;)
  {
    // XXX: step 4, accept

    struct sockaddr_in peer_address;
    socklen_t peer_address_length;
    int new_accepted_socket;

    peer_address_length = sizeof(peer_address);

    // int accept(int s, struct sockaddr *addr, socklen_t *addrlen);
    if ((new_accepted_socket = accept(fd, (struct sockaddr *) &peer_address, &peer_address_length)) < 0)
    {
      fprintf(stderr, "ERROR: call accept() failed: %s\n", strerror(errno));
      // FIXME: deal with this error.
      exit(1);
    }

#ifdef _DEBUG_
    fprintf(stdout, "DEBUG: call accept() successed, new accepted socket = %d\n", new_accepted_socket);
    // char *inet_ntoa(struct in_addr in);
    fprintf(stdout, "DEBUG: new accepted from %s:%d.\n", inet_ntoa(peer_address.sin_addr), ntohs(peer_address.sin_port));;
#endif
  }

  // XXX: step 5, close.

  close(fd);
  return 0;
}