ipc/chromium/src/third_party/libevent/sample/dns-example.c@ca08bd8f51b2
ipc/chromium/src/third_party/libevent/sample/dns-example.c
Wed, 31 Dec 2014 06:55:46 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:55:46 +0100
- changeset 1
- ca08bd8f51b2
- permissions
- -rw-r--r--
Added tag TORBROWSER_REPLICA for changeset 6474c204b198
1 /*
2 This example code shows how to use the high-level, low-level, and
3 server-level interfaces of evdns.
5 XXX It's pretty ugly and should probably be cleaned up.
6 */
8 #include <event2/event-config.h>
10 /* Compatibility for possible missing IPv6 declarations */
11 #include "../ipv6-internal.h"
13 #include <sys/types.h>
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
24 #include <event2/event.h>
25 #include <event2/dns.h>
26 #include <event2/dns_struct.h>
27 #include <event2/util.h>
29 #ifdef _EVENT_HAVE_NETINET_IN6_H
30 #include <netinet/in6.h>
31 #endif
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
37 #define u32 ev_uint32_t
38 #define u8 ev_uint8_t
40 static const char *
41 debug_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 }
53 static void
54 main_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 }
71 static void
72 gai_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 }
99 static void
100 evdns_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 }
128 r = evdns_server_request_respond(req, 0);
129 if (r<0)
130 printf("eeek, couldn't send reply.\n");
131 }
133 static int verbose = 0;
135 static void
136 logfn(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 }
142 int
143 main(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 }
174 #ifdef WIN32
175 {
176 WSADATA WSAData;
177 WSAStartup(0x101, &WSAData);
178 }
179 #endif
181 event_base = event_base_new();
182 evdns_base = evdns_base_new(event_base, 0);
183 evdns_set_log_fn(logfn);
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");
214 if (res < 0) {
215 fprintf(stderr, "Couldn't configure nameservers");
216 return 1;
217 }
218 }
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 }
