The Tor Browser: ipc/chromium/src/third_party/libevent/sample/dns-example.c@8bccb770b82d (annotated)

ipc/chromium/src/third_party/libevent/sample/dns-example.c@8bccb770b82d (annotated)

ipc/chromium/src/third_party/libevent/sample/dns-example.c

Wed, 31 Dec 2014 13:27:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 13:27:57 +0100
branch: TOR_BUG_3246
changeset 6: 8bccb770b82d
permissions: -rw-r--r--

Ignore runtime configuration files generated during quality assurance.

 /*
   This example code shows how to use the high-level, low-level, and
   server-level interfaces of evdns.
   XXX It's pretty ugly and should probably be cleaned up.
  */
 #include <event2/event-config.h>
 /* Compatibility for possible missing IPv6 declarations */
 #include "../ipv6-internal.h"
 #include <sys/types.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
 gai_callback(int err, struct evutil_addrinfo *ai, void *arg)
 {
 	const char *name = arg;
 	int i;
 	if (err) {
 		printf("%s: %s\n", name, evutil_gai_strerror(err));
 	}
 	if (ai && ai->ai_canonname)
 		printf("    %s ==> %s\n", name, ai->ai_canonname);
 	for (i=0; ai; ai = ai->ai_next, ++i) {
 		char buf[128];
 		if (ai->ai_family == PF_INET) {
 			struct sockaddr_in *sin =
 			    (struct sockaddr_in*)ai->ai_addr;
 			evutil_inet_ntop(AF_INET, &sin->sin_addr, buf,
 			    sizeof(buf));
 			printf("[%d] %s: %s\n",i,name,buf);
 		} else {
 			struct sockaddr_in6 *sin6 =
 			    (struct sockaddr_in6*)ai->ai_addr;
 			evutil_inet_ntop(AF_INET6, &sin6->sin6_addr, buf,
 			    sizeof(buf));
 			printf("[%d] %s: %s\n",i,name,buf);
 		}
 	}
 }
 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,
 , &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);
 			if (r<0)
 				printf("ugh, no luck");
 		} 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, use_getaddrinfo = 0;
 	struct event_base *event_base = NULL;
 	struct evdns_base *evdns_base = NULL;
 	const char *resolv_conf = NULL;
 	if (c<2) {
 		fprintf(stderr, "syntax: %s [-x] [-v] [-c resolv.conf] 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], "-g"))
 			use_getaddrinfo = 1;
 		else if (!strcmp(v[idx], "-servertest"))
 			servertest = 1;
 		else if (!strcmp(v[idx], "-c")) {
 			if (idx + 1 < c)
 				resolv_conf = v[++idx];
 			else
 				fprintf(stderr, "-c needs an argument\n");
 		} else
 			fprintf(stderr, "Unknown option %s\n", v[idx]);
 		++idx;
 	}
 #ifdef WIN32
 	{
 		WSADATA WSAData;
 		WSAStartup(0x101, &WSAData);
 	}
 #endif
 	event_base = event_base_new();
 	evdns_base = evdns_base_new(event_base, 0);
 	evdns_set_log_fn(logfn);
 	if (servertest) {
 		evutil_socket_t sock;
 		struct sockaddr_in my_addr;
 		sock = socket(PF_INET, SOCK_DGRAM, 0);
 		if (sock == -1) {
 			perror("socket");
 			exit(1);
 		}
 		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) {
 		int res;
 #ifdef WIN32
 		if (resolv_conf == NULL)
 			res = evdns_base_config_windows_nameservers(evdns_base);
 		else
 #endif
 			res = evdns_base_resolv_conf_parse(evdns_base,
 			    DNS_OPTION_NAMESERVERS,
 			    resolv_conf ? resolv_conf : "/etc/resolv.conf");
 		if (res < 0) {
 			fprintf(stderr, "Couldn't configure nameservers");
 			return 1;
 		}
 	}
 	printf("EVUTIL_AI_CANONNAME in example = %d\n", EVUTIL_AI_CANONNAME);
 	for (; idx < c; ++idx) {
 		if (reverse) {
 			struct in_addr addr;
 			if (evutil_inet_pton(AF_INET, v[idx], &addr)!=1) {
 				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 if (use_getaddrinfo) {
 			struct evutil_addrinfo hints;
 			memset(&hints, 0, sizeof(hints));
 			hints.ai_family = PF_UNSPEC;
 			hints.ai_protocol = IPPROTO_TCP;
 			hints.ai_flags = EVUTIL_AI_CANONNAME;
 			fprintf(stderr, "resolving (fwd) %s...\n",v[idx]);
 			evdns_getaddrinfo(evdns_base, v[idx], NULL, &hints,
 			    gai_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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ipc/chromium/src/third_party/libevent/sample/dns-example.c@8bccb770b82d (annotated)

ipc/chromium/src/third_party/libevent/sample/dns-example.c