1/*
2  This example code shows how to use the high-level, low-level, and
3  server-level interfaces of evdns.
4
5  XXX It's pretty ugly and should probably be cleaned up.
6 */
7
8#include <event2/event-config.h>
9
10/* Compatibility for possible missing IPv6 declarations */
11#include "../ipv6-internal.h"
12
13#include <sys/types.h>
14
15#ifdef WIN32
16#include <winsock2.h>
17#include <ws2tcpip.h>
18#else
19#include <sys/socket.h>
20#include <netinet/in.h>
21#include <arpa/inet.h>
22#endif
23
24#include <event2/event.h>
25#include <event2/dns.h>
26#include <event2/dns_struct.h>
27#include <event2/util.h>
28
29#ifdef _EVENT_HAVE_NETINET_IN6_H
30#include <netinet/in6.h>
31#endif
32
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36
37#define u32 ev_uint32_t
38#define u8 ev_uint8_t
39
40static const char *
41debug_ntoa(u32 address)
42{
43	static char buf[32];
44	u32 a = ntohl(address);
45	evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d",
46					(int)(u8)((a>>24)&0xff),
47					(int)(u8)((a>>16)&0xff),
48					(int)(u8)((a>>8 )&0xff),
49					(int)(u8)((a	)&0xff));
50	return buf;
51}
52
53static void
54main_callback(int result, char type, int count, int ttl,
55			  void *addrs, void *orig) {
56	char *n = (char*)orig;
57	int i;
58	for (i = 0; i < count; ++i) {
59		if (type == DNS_IPv4_A) {
60			printf("%s: %s\n", n, debug_ntoa(((u32*)addrs)[i]));
61		} else if (type == DNS_PTR) {
62			printf("%s: %s\n", n, ((char**)addrs)[i]);
63		}
64	}
65	if (!count) {
66		printf("%s: No answer (%d)\n", n, result);
67	}
68	fflush(stdout);
69}
70
71static void
72gai_callback(int err, struct evutil_addrinfo *ai, void *arg)
73{
74	const char *name = arg;
75	int i;
76	if (err) {
77		printf("%s: %s\n", name, evutil_gai_strerror(err));
78	}
79	if (ai && ai->ai_canonname)
80		printf("    %s ==> %s\n", name, ai->ai_canonname);
81	for (i=0; ai; ai = ai->ai_next, ++i) {
82		char buf[128];
83		if (ai->ai_family == PF_INET) {
84			struct sockaddr_in *sin =
85			    (struct sockaddr_in*)ai->ai_addr;
86			evutil_inet_ntop(AF_INET, &sin->sin_addr, buf,
87			    sizeof(buf));
88			printf("[%d] %s: %s\n",i,name,buf);
89		} else {
90			struct sockaddr_in6 *sin6 =
91			    (struct sockaddr_in6*)ai->ai_addr;
92			evutil_inet_ntop(AF_INET6, &sin6->sin6_addr, buf,
93			    sizeof(buf));
94			printf("[%d] %s: %s\n",i,name,buf);
95		}
96	}
97}
98
99static void
100evdns_server_callback(struct evdns_server_request *req, void *data)
101{
102	int i, r;
103	(void)data;
104	/* dummy; give 192.168.11.11 as an answer for all A questions,
105	 *	give foo.bar.example.com as an answer for all PTR questions. */
106	for (i = 0; i < req->nquestions; ++i) {
107		u32 ans = htonl(0xc0a80b0bUL);
108		if (req->questions[i]->type == EVDNS_TYPE_A &&
109		    req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
110			printf(" -- replying for %s (A)\n", req->questions[i]->name);
111			r = evdns_server_request_add_a_reply(req, req->questions[i]->name,
112										  1, &ans, 10);
113			if (r<0)
114				printf("eeep, didn't work.\n");
115		} else if (req->questions[i]->type == EVDNS_TYPE_PTR &&
116		    req->questions[i]->dns_question_class == EVDNS_CLASS_INET) {
117			printf(" -- replying for %s (PTR)\n", req->questions[i]->name);
118			r = evdns_server_request_add_ptr_reply(req, NULL, req->questions[i]->name,
119											"foo.bar.example.com", 10);
120			if (r<0)
121				printf("ugh, no luck");
122		} else {
123			printf(" -- skipping %s [%d %d]\n", req->questions[i]->name,
124				   req->questions[i]->type, req->questions[i]->dns_question_class);
125		}
126	}
127
128	r = evdns_server_request_respond(req, 0);
129	if (r<0)
130		printf("eeek, couldn't send reply.\n");
131}
132
133static int verbose = 0;
134
135static void
136logfn(int is_warn, const char *msg) {
137	if (!is_warn && !verbose)
138		return;
139	fprintf(stderr, "%s: %s\n", is_warn?"WARN":"INFO", msg);
140}
141
142int
143main(int c, char **v) {
144	int idx;
145	int reverse = 0, servertest = 0, use_getaddrinfo = 0;
146	struct event_base *event_base = NULL;
147	struct evdns_base *evdns_base = NULL;
148	const char *resolv_conf = NULL;
149	if (c<2) {
150		fprintf(stderr, "syntax: %s [-x] [-v] [-c resolv.conf] hostname\n", v[0]);
151		fprintf(stderr, "syntax: %s [-servertest]\n", v[0]);
152		return 1;
153	}
154	idx = 1;
155	while (idx < c && v[idx][0] == '-') {
156		if (!strcmp(v[idx], "-x"))
157			reverse = 1;
158		else if (!strcmp(v[idx], "-v"))
159			verbose = 1;
160		else if (!strcmp(v[idx], "-g"))
161			use_getaddrinfo = 1;
162		else if (!strcmp(v[idx], "-servertest"))
163			servertest = 1;
164		else if (!strcmp(v[idx], "-c")) {
165			if (idx + 1 < c)
166				resolv_conf = v[++idx];
167			else
168				fprintf(stderr, "-c needs an argument\n");
169		} else
170			fprintf(stderr, "Unknown option %s\n", v[idx]);
171		++idx;
172	}
173
174#ifdef WIN32
175	{
176		WSADATA WSAData;
177		WSAStartup(0x101, &WSAData);
178	}
179#endif
180
181	event_base = event_base_new();
182	evdns_base = evdns_base_new(event_base, 0);
183	evdns_set_log_fn(logfn);
184
185	if (servertest) {
186		evutil_socket_t sock;
187		struct sockaddr_in my_addr;
188		sock = socket(PF_INET, SOCK_DGRAM, 0);
189		if (sock == -1) {
190			perror("socket");
191			exit(1);
192		}
193		evutil_make_socket_nonblocking(sock);
194		my_addr.sin_family = AF_INET;
195		my_addr.sin_port = htons(10053);
196		my_addr.sin_addr.s_addr = INADDR_ANY;
197		if (bind(sock, (struct sockaddr*)&my_addr, sizeof(my_addr))<0) {
198			perror("bind");
199			exit(1);
200		}
201		evdns_add_server_port_with_base(event_base, sock, 0, evdns_server_callback, NULL);
202	}
203	if (idx < c) {
204		int res;
205#ifdef WIN32
206		if (resolv_conf == NULL)
207			res = evdns_base_config_windows_nameservers(evdns_base);
208		else
209#endif
210			res = evdns_base_resolv_conf_parse(evdns_base,
211			    DNS_OPTION_NAMESERVERS,
212			    resolv_conf ? resolv_conf : "/etc/resolv.conf");
213
214		if (res < 0) {
215			fprintf(stderr, "Couldn't configure nameservers");
216			return 1;
217		}
218	}
219
220	printf("EVUTIL_AI_CANONNAME in example = %d\n", EVUTIL_AI_CANONNAME);
221	for (; idx < c; ++idx) {
222		if (reverse) {
223			struct in_addr addr;
224			if (evutil_inet_pton(AF_INET, v[idx], &addr)!=1) {
225				fprintf(stderr, "Skipping non-IP %s\n", v[idx]);
226				continue;
227			}
228			fprintf(stderr, "resolving %s...\n",v[idx]);
229			evdns_base_resolve_reverse(evdns_base, &addr, 0, main_callback, v[idx]);
230		} else if (use_getaddrinfo) {
231			struct evutil_addrinfo hints;
232			memset(&hints, 0, sizeof(hints));
233			hints.ai_family = PF_UNSPEC;
234			hints.ai_protocol = IPPROTO_TCP;
235			hints.ai_flags = EVUTIL_AI_CANONNAME;
236			fprintf(stderr, "resolving (fwd) %s...\n",v[idx]);
237			evdns_getaddrinfo(evdns_base, v[idx], NULL, &hints,
238			    gai_callback, v[idx]);
239		} else {
240			fprintf(stderr, "resolving (fwd) %s...\n",v[idx]);
241			evdns_base_resolve_ipv4(evdns_base, v[idx], 0, main_callback, v[idx]);
242		}
243	}
244	fflush(stdout);
245	event_base_dispatch(event_base);
246	return 0;
247}
248
249