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 #include "../ipv6-internal.h" 11 12 #include <sys/types.h> 13 14 #ifdef WIN32 15 #include <winsock2.h> 16 #include <ws2tcpip.h> 17 #else 18 #include <sys/socket.h> 19 #include <netinet/in.h> 20 #include <arpa/inet.h> 21 #endif 22 23 #include <event2/event.h> 24 #include <event2/dns.h> 25 #include <event2/dns_struct.h> 26 #include <event2/util.h> 27 28 #ifdef _EVENT_HAVE_NETINET_IN6_H 29 #include <netinet/in6.h> 30 #endif 31 32 #include <stdio.h> 33 #include <stdlib.h> 34 #include <string.h> 35 36 #define u32 ev_uint32_t 37 #define u8 ev_uint8_t 38 39 static const char * 40 debug_ntoa(u32 address) 41 { 42 static char buf[32]; 43 u32 a = ntohl(address); 44 evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d", 45 (int)(u8)((a>>24)&0xff), 46 (int)(u8)((a>>16)&0xff), 47 (int)(u8)((a>>8 )&0xff), 48 (int)(u8)((a )&0xff)); 49 return buf; 50 } 51 52 static void 53 main_callback(int result, char type, int count, int ttl, 54 void *addrs, void *orig) { 55 char *n = (char*)orig; 56 int i; 57 for (i = 0; i < count; ++i) { 58 if (type == DNS_IPv4_A) { 59 printf("%s: %s\n", n, debug_ntoa(((u32*)addrs)[i])); 60 } else if (type == DNS_PTR) { 61 printf("%s: %s\n", n, ((char**)addrs)[i]); 62 } 63 } 64 if (!count) { 65 printf("%s: No answer (%d)\n", n, result); 66 } 67 fflush(stdout); 68 } 69 70 static void 71 gai_callback(int err, struct evutil_addrinfo *ai, void *arg) 72 { 73 const char *name = arg; 74 struct evutil_addrinfo *ai_first = NULL; 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 if (ai_first) 98 evutil_freeaddrinfo(ai_first); 99 } 100 101 static void 102 evdns_server_callback(struct evdns_server_request *req, void *data) 103 { 104 int i, r; 105 (void)data; 106 /* dummy; give 192.168.11.11 as an answer for all A questions, 107 * give foo.bar.example.com as an answer for all PTR questions. */ 108 for (i = 0; i < req->nquestions; ++i) { 109 u32 ans = htonl(0xc0a80b0bUL); 110 if (req->questions[i]->type == EVDNS_TYPE_A && 111 req->questions[i]->dns_question_class == EVDNS_CLASS_INET) { 112 printf(" -- replying for %s (A)\n", req->questions[i]->name); 113 r = evdns_server_request_add_a_reply(req, req->questions[i]->name, 114 1, &ans, 10); 115 if (r<0) 116 printf("eeep, didn't work.\n"); 117 } else if (req->questions[i]->type == EVDNS_TYPE_PTR && 118 req->questions[i]->dns_question_class == EVDNS_CLASS_INET) { 119 printf(" -- replying for %s (PTR)\n", req->questions[i]->name); 120 r = evdns_server_request_add_ptr_reply(req, NULL, req->questions[i]->name, 121 "foo.bar.example.com", 10); 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 } 132 133 static int verbose = 0; 134 135 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 } 141 142 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 if (c<2) { 149 fprintf(stderr, "syntax: %s [-x] [-v] hostname\n", v[0]); 150 fprintf(stderr, "syntax: %s [-servertest]\n", v[0]); 151 return 1; 152 } 153 idx = 1; 154 while (idx < c && v[idx][0] == '-') { 155 if (!strcmp(v[idx], "-x")) 156 reverse = 1; 157 else if (!strcmp(v[idx], "-v")) 158 verbose = 1; 159 else if (!strcmp(v[idx], "-g")) 160 use_getaddrinfo = 1; 161 else if (!strcmp(v[idx], "-servertest")) 162 servertest = 1; 163 else 164 fprintf(stderr, "Unknown option %s\n", v[idx]); 165 ++idx; 166 } 167 168 event_base = event_base_new(); 169 evdns_base = evdns_base_new(event_base, 0); 170 evdns_set_log_fn(logfn); 171 172 if (servertest) { 173 evutil_socket_t sock; 174 struct sockaddr_in my_addr; 175 sock = socket(PF_INET, SOCK_DGRAM, 0); 176 evutil_make_socket_nonblocking(sock); 177 my_addr.sin_family = AF_INET; 178 my_addr.sin_port = htons(10053); 179 my_addr.sin_addr.s_addr = INADDR_ANY; 180 if (bind(sock, (struct sockaddr*)&my_addr, sizeof(my_addr))<0) { 181 perror("bind"); 182 exit(1); 183 } 184 evdns_add_server_port_with_base(event_base, sock, 0, evdns_server_callback, NULL); 185 } 186 if (idx < c) { 187 #ifdef WIN32 188 evdns_base_config_windows_nameservers(evdns_base); 189 #else 190 evdns_base_resolv_conf_parse(evdns_base, DNS_OPTION_NAMESERVERS, 191 "/etc/resolv.conf"); 192 #endif 193 } 194 195 printf("EVUTIL_AI_CANONNAME in example = %d\n", EVUTIL_AI_CANONNAME); 196 for (; idx < c; ++idx) { 197 if (reverse) { 198 struct in_addr addr; 199 if (evutil_inet_pton(AF_INET, v[idx], &addr)!=1) { 200 fprintf(stderr, "Skipping non-IP %s\n", v[idx]); 201 continue; 202 } 203 fprintf(stderr, "resolving %s...\n",v[idx]); 204 evdns_base_resolve_reverse(evdns_base, &addr, 0, main_callback, v[idx]); 205 } else if (use_getaddrinfo) { 206 struct evutil_addrinfo hints; 207 memset(&hints, 0, sizeof(hints)); 208 hints.ai_family = PF_UNSPEC; 209 hints.ai_protocol = IPPROTO_TCP; 210 hints.ai_flags = EVUTIL_AI_CANONNAME; 211 fprintf(stderr, "resolving (fwd) %s...\n",v[idx]); 212 evdns_getaddrinfo(evdns_base, v[idx], NULL, &hints, 213 gai_callback, v[idx]); 214 } else { 215 fprintf(stderr, "resolving (fwd) %s...\n",v[idx]); 216 evdns_base_resolve_ipv4(evdns_base, v[idx], 0, main_callback, v[idx]); 217 } 218 } 219 fflush(stdout); 220 event_base_dispatch(event_base); 221 return 0; 222 } 223 224