10.3 回显服务器

  1. #include <event2/listener.h>
  2. #include <event2/bufferevent.h>
  3. #include <event2/buffer.h>
  5. #include <arpa/inet.h>
  7. #include <string.h>
  8. #include <stdlib.h>
  9. #include <stdio.h>
  10. #include <errno.h>
  12. static void
  13. echo_read_cb(struct bufferevent *bev, void *ctx)
  14. {
  15.         /* This callback is invoked when there is data to read on bev. */
  16.         struct evbuffer *input = bufferevent_get_input(bev);
  17.         struct evbuffer *output = bufferevent_get_output(bev);
  19.         /* Copy all the data from the input buffer to the output buffer. */
  20.         evbuffer_add_buffer(output, input);
  21. }
  23. static void
  24. echo_event_cb(struct bufferevent *bev, short events, void *ctx)
  25. {
  26.         if (events & BEV_EVENT_ERROR)
  27.                 perror("Error from bufferevent");
  28.         if (events & (BEV_EVENT_EOF | BEV_EVENT_ERROR)) {
  29.                 bufferevent_free(bev);
  30.         }
  31. }
  33. static void
  34. accept_conn_cb(struct evconnlistener *listener,
  35.     evutil_socket_t fd, struct sockaddr *address, int socklen,
  36.     void *ctx)
  37. {
  38.         /* We got a new connection! Set up a bufferevent for it. */
  39.         struct event_base *base = evconnlistener_get_base(listener);
  40.         struct bufferevent *bev = bufferevent_socket_new(
  41.                 base, fd, BEV_OPT_CLOSE_ON_FREE);
  43.         bufferevent_setcb(bev, echo_read_cb, NULL, echo_event_cb, NULL);
  45.         bufferevent_enable(bev, EV_READ|EV_WRITE);
  46. }
  48. static void
  49. accept_error_cb(struct evconnlistener *listener, void *ctx)
  50. {
  51.         struct event_base *base = evconnlistener_get_base(listener);
  52.         int err = EVUTIL_SOCKET_ERROR();
  53.         fprintf(stderr, "Got an error %d (%s) on the listener. "
  54.                 "Shutting down.\n", err, evutil_socket_error_to_string(err));
  56.         event_base_loopexit(base, NULL);
  57. }
  59. int
  60. main(int argc, char **argv)
  61. {
  62.         struct event_base *base;
  63.         struct evconnlistener *listener;
  64.         struct sockaddr_in sin;
  66.         int port = 9876;
  68.         if (argc > 1) {
  69.                 port = atoi(argv[1]);
  70.         }
  71.         if (port<=0 || port>65535) {
  72.                 puts("Invalid port");
  73.                 return 1;
  74.         }
  76.         base = event_base_new();
  77.         if (!base) {
  78.                 puts("Couldn't open event base");
  79.                 return 1;
  80.         }
  82.         /* Clear the sockaddr before using it, in case there are extra
  83.          * platform-specific fields that can mess us up. */
  84.         memset(&sin, 0, sizeof(sin));
  85.         /* This is an INET address */
  86.         sin.sin_family = AF_INET;
  87.         /* Listen on 0.0.0.0 */
  88.         sin.sin_addr.s_addr = htonl(0);
  89.         /* Listen on the given port. */
  90.         sin.sin_port = htons(port);
  92.         listener = evconnlistener_new_bind(base, accept_conn_cb, NULL,
  93.             LEV_OPT_CLOSE_ON_FREE|LEV_OPT_REUSEABLE, -1,
  94.             (struct sockaddr*)&sin, sizeof(sin));
  95.         if (!listener) {
  96.                 perror("Couldn't create listener");
  97.                 return 1;
  98.         }
  99.         evconnlistener_set_error_cb(listener, accept_error_cb);
  101.         event_base_dispatch(base);
  102.         return 0;
  103. }