kc3-lang/libevent/sample/dns-example.c

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• Hash : ae5fbf49
  Author :
  Date : 2009-11-05T22:24:21
  

  Actually add the new dns-example.c code. :p
  
  svn:r1512
  

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• sample/dns-example.c

• 
  #include <event-config.h>
  
  #ifdef WIN32
  #include <winsock2.h>
  #include <ws2tcpip.h>
  #else
  #include <sys/socket.h>
  #include <netinet/in.h>
  #include <arpa/inet.h>
  #endif
  
  #include <event2/event.h>
  #include <event2/dns.h>
  #include <event2/dns_struct.h>
  #include <event2/util.h>
  
  #ifdef _EVENT_HAVE_NETINET_IN6_H
  #include <netinet/in6.h>
  #endif
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #define u32 ev_uint32_t
  #define u8 ev_uint8_t
  
  static const char *
  debug_ntoa(u32 address)
  {
  	static char buf[32];
  	u32 a = ntohl(address);
  	evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d",
  					(int)(u8)((a>>24)&0xff),
  					(int)(u8)((a>>16)&0xff),
  					(int)(u8)((a>>8 )&0xff),
  					(int)(u8)((a	)&0xff));
  	return buf;
  }
  
  static void
  main_callback(int result, char type, int count, int ttl,
  			  void *addrs, void *orig) {
  	char *n = (char*)orig;
  	int i;
  	for (i = 0; i < count; ++i) {
  		if (type == DNS_IPv4_A) {
  			printf("%s: %s\n", n, debug_ntoa(((u32*)addrs)[i]));
  		} else if (type == DNS_PTR) {
  			printf("%s: %s\n", n, ((char**)addrs)[i]);
  		}
  	}
  	if (!count) {
  		printf("%s: No answer (%d)\n", n, result);
  	}
  	fflush(stdout);
  }
  
  static void
  evdns_server_callback(struct evdns_server_request *req, void *data)
  {
  	int i, r;
  	(void)data;
  	/* dummy; give 192.168.11.11 as an answer for all A questions,
  	 *	give foo.bar.example.com as an answer for all PTR questions. */
  	for (i = 0; i < req->nquestions; ++i) {
  		u32 ans = htonl(0xc0a80b0bUL);
  		if (req->questions[i]->type == EVDNS_TYPE_A &&
  		    req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
  			printf(" -- replying for %s (A)\n", req->questions[i]->name);
  			r = evdns_server_request_add_a_reply(req, req->questions[i]->name,
  										  1, &ans, 10);
  			if (r<0)
  				printf("eeep, didn't work.\n");
  		} else if (req->questions[i]->type == EVDNS_TYPE_PTR &&
  		    req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
  			printf(" -- replying for %s (PTR)\n", req->questions[i]->name);
  			r = evdns_server_request_add_ptr_reply(req, NULL, req->questions[i]->name,
  											"foo.bar.example.com", 10);
  		} else {
  			printf(" -- skipping %s [%d %d]\n", req->questions[i]->name,
  				   req->questions[i]->type, req->questions[i]->dns_question_class);
  		}
  	}
  
  	r = evdns_server_request_respond(req, 0);
  	if (r<0)
  		printf("eeek, couldn't send reply.\n");
  }
  
  static int verbose = 0;
  
  static void
  logfn(int is_warn, const char *msg) {
  	if (!is_warn && !verbose)
  		return;
  	fprintf(stderr, "%s: %s\n", is_warn?"WARN":"INFO", msg);
  }
  
  int
  main(int c, char **v) {
  	int idx;
  	int reverse = 0, servertest = 0;
  	struct event_base *event_base = NULL;
  	struct evdns_base *evdns_base = NULL;
  	if (c<2) {
  		fprintf(stderr, "syntax: %s [-x] [-v] hostname\n", v[0]);
  		fprintf(stderr, "syntax: %s [-servertest]\n", v[0]);
  		return 1;
  	}
  	idx = 1;
  	while (idx < c && v[idx][0] == '-') {
  		if (!strcmp(v[idx], "-x"))
  			reverse = 1;
  		else if (!strcmp(v[idx], "-v"))
  			verbose = 1;
  		else if (!strcmp(v[idx], "-servertest"))
  			servertest = 1;
  		else
  			fprintf(stderr, "Unknown option %s\n", v[idx]);
  		++idx;
  	}
  
  	event_base = event_base_new();
  	evdns_base = evdns_base_new(event_base, 0);
  	evdns_set_log_fn(logfn);
  
  	if (servertest) {
  		int sock;
  		struct sockaddr_in my_addr;
  		sock = socket(PF_INET, SOCK_DGRAM, 0);
  		evutil_make_socket_nonblocking(sock);
  		my_addr.sin_family = AF_INET;
  		my_addr.sin_port = htons(10053);
  		my_addr.sin_addr.s_addr = INADDR_ANY;
  		if (bind(sock, (struct sockaddr*)&my_addr, sizeof(my_addr))<0) {
  			perror("bind");
  			exit(1);
  		}
  		evdns_add_server_port_with_base(event_base, sock, 0, evdns_server_callback, NULL);
  	}
  	if (idx < c) {
  #ifdef WIN32
  		evdns_base_config_windows_nameservers(evdns_base);
  #else
  		evdns_base_resolv_conf_parse(evdns_base, DNS_OPTION_NAMESERVERS,
  		    "/etc/resolv.conf");
  #endif
  	}
  	for (; idx < c; ++idx) {
  		if (reverse) {
  			struct in_addr addr;
  			if (!inet_aton(v[idx], &addr)) {
  				fprintf(stderr, "Skipping non-IP %s\n", v[idx]);
  				continue;
  			}
  			fprintf(stderr, "resolving %s...\n",v[idx]);
  			evdns_base_resolve_reverse(evdns_base, &addr, 0, main_callback, v[idx]);
  		} else {
  			fprintf(stderr, "resolving (fwd) %s...\n",v[idx]);
  			evdns_base_resolve_ipv4(evdns_base, v[idx], 0, main_callback, v[idx]);
  		}
  	}
  	fflush(stdout);
  	event_base_dispatch(event_base);
  	return 0;
  }
  
  

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