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257 lines
6.5 KiB
257 lines
6.5 KiB
/* |
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This example code shows how to use the high-level, low-level, and |
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server-level interfaces of evdns. |
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XXX It's pretty ugly and should probably be cleaned up. |
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*/ |
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#include <event2/event-config.h> |
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/* Compatibility for possible missing IPv6 declarations */ |
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#include "../ipv6-internal.h" |
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#include <sys/types.h> |
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#ifdef EVENT__HAVE_UNISTD_H |
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#include <unistd.h> |
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#endif |
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#ifdef _WIN32 |
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#include <winsock2.h> |
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#include <ws2tcpip.h> |
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#include <getopt.h> |
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#else |
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#include <sys/socket.h> |
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#include <netinet/in.h> |
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#include <arpa/inet.h> |
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#endif |
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#include <event2/event.h> |
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#include <event2/dns.h> |
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#include <event2/dns_struct.h> |
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#include <event2/util.h> |
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#ifdef EVENT__HAVE_NETINET_IN6_H |
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#include <netinet/in6.h> |
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#endif |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#define u32 ev_uint32_t |
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#define u8 ev_uint8_t |
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static const char * |
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debug_ntoa(u32 address) |
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{ |
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static char buf[32]; |
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u32 a = ntohl(address); |
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evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d", |
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(int)(u8)((a>>24)&0xff), |
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(int)(u8)((a>>16)&0xff), |
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(int)(u8)((a>>8 )&0xff), |
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(int)(u8)((a )&0xff)); |
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return buf; |
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} |
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static void |
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main_callback(int result, char type, int count, int ttl, |
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void *addrs, void *orig) { |
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char *n = (char*)orig; |
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int i; |
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for (i = 0; i < count; ++i) { |
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if (type == DNS_IPv4_A) { |
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printf("%s: %s\n", n, debug_ntoa(((u32*)addrs)[i])); |
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} else if (type == DNS_PTR) { |
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printf("%s: %s\n", n, ((char**)addrs)[i]); |
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} |
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} |
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if (!count) { |
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printf("%s: No answer (%d)\n", n, result); |
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} |
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fflush(stdout); |
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} |
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static void |
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gai_callback(int err, struct evutil_addrinfo *ai, void *arg) |
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{ |
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const char *name = arg; |
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int i; |
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if (err) { |
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printf("%s: %s\n", name, evutil_gai_strerror(err)); |
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} |
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if (ai && ai->ai_canonname) |
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printf(" %s ==> %s\n", name, ai->ai_canonname); |
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for (i=0; ai; ai = ai->ai_next, ++i) { |
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char buf[128]; |
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if (ai->ai_family == PF_INET) { |
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struct sockaddr_in *sin = |
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(struct sockaddr_in*)ai->ai_addr; |
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evutil_inet_ntop(AF_INET, &sin->sin_addr, buf, |
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sizeof(buf)); |
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printf("[%d] %s: %s\n",i,name,buf); |
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} else { |
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struct sockaddr_in6 *sin6 = |
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(struct sockaddr_in6*)ai->ai_addr; |
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evutil_inet_ntop(AF_INET6, &sin6->sin6_addr, buf, |
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sizeof(buf)); |
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printf("[%d] %s: %s\n",i,name,buf); |
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} |
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} |
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} |
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static void |
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evdns_server_callback(struct evdns_server_request *req, void *data) |
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{ |
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int i, r; |
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(void)data; |
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/* dummy; give 192.168.11.11 as an answer for all A questions, |
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* give foo.bar.example.com as an answer for all PTR questions. */ |
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for (i = 0; i < req->nquestions; ++i) { |
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u32 ans = htonl(0xc0a80b0bUL); |
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if (req->questions[i]->type == EVDNS_TYPE_A && |
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req->questions[i]->dns_question_class == EVDNS_CLASS_INET) { |
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printf(" -- replying for %s (A)\n", req->questions[i]->name); |
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r = evdns_server_request_add_a_reply(req, req->questions[i]->name, |
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1, &ans, 10); |
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if (r<0) |
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printf("eeep, didn't work.\n"); |
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} else if (req->questions[i]->type == EVDNS_TYPE_PTR && |
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req->questions[i]->dns_question_class == EVDNS_CLASS_INET) { |
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printf(" -- replying for %s (PTR)\n", req->questions[i]->name); |
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r = evdns_server_request_add_ptr_reply(req, NULL, req->questions[i]->name, |
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"foo.bar.example.com", 10); |
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if (r<0) |
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printf("ugh, no luck"); |
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} else { |
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printf(" -- skipping %s [%d %d]\n", req->questions[i]->name, |
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req->questions[i]->type, req->questions[i]->dns_question_class); |
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} |
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} |
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r = evdns_server_request_respond(req, 0); |
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if (r<0) |
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printf("eeek, couldn't send reply.\n"); |
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} |
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static int verbose = 0; |
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static void |
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logfn(int is_warn, const char *msg) { |
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if (!is_warn && !verbose) |
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return; |
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fprintf(stderr, "%s: %s\n", is_warn?"WARN":"INFO", msg); |
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} |
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int |
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main(int c, char **v) { |
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struct options { |
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int reverse; |
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int use_getaddrinfo; |
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int servertest; |
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const char *resolv_conf; |
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const char *ns; |
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}; |
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struct options o; |
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char opt; |
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struct event_base *event_base = NULL; |
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struct evdns_base *evdns_base = NULL; |
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memset(&o, 0, sizeof(o)); |
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if (c < 2) { |
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fprintf(stderr, "syntax: %s [-x] [-v] [-c resolv.conf] [-s ns] hostname\n", v[0]); |
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fprintf(stderr, "syntax: %s [-T]\n", v[0]); |
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return 1; |
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} |
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while ((opt = getopt(c, v, "xvc:Ts:")) != -1) { |
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switch (opt) { |
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case 'x': o.reverse = 1; break; |
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case 'v': ++verbose; break; |
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case 'g': o.use_getaddrinfo = 1; break; |
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case 'T': o.servertest = 1; break; |
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case 'c': o.resolv_conf = optarg; break; |
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case 's': o.ns = optarg; break; |
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default : fprintf(stderr, "Unknown option %c\n", opt); break; |
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} |
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} |
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#ifdef _WIN32 |
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{ |
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WSADATA WSAData; |
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WSAStartup(0x101, &WSAData); |
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} |
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#endif |
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event_base = event_base_new(); |
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evdns_base = evdns_base_new(event_base, EVDNS_BASE_DISABLE_WHEN_INACTIVE); |
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evdns_set_log_fn(logfn); |
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if (o.servertest) { |
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evutil_socket_t sock; |
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struct sockaddr_in my_addr; |
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sock = socket(PF_INET, SOCK_DGRAM, 0); |
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if (sock == -1) { |
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perror("socket"); |
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exit(1); |
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} |
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evutil_make_socket_nonblocking(sock); |
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my_addr.sin_family = AF_INET; |
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my_addr.sin_port = htons(10053); |
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my_addr.sin_addr.s_addr = INADDR_ANY; |
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if (bind(sock, (struct sockaddr*)&my_addr, sizeof(my_addr))<0) { |
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perror("bind"); |
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exit(1); |
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} |
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evdns_add_server_port_with_base(event_base, sock, 0, evdns_server_callback, NULL); |
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} |
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if (optind < c) { |
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int res; |
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#ifdef _WIN32 |
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if (o.resolv_conf == NULL && !o.ns) |
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res = evdns_base_config_windows_nameservers(evdns_base); |
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else |
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#endif |
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if (o.ns) |
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res = evdns_base_nameserver_ip_add(evdns_base, o.ns); |
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else |
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res = evdns_base_resolv_conf_parse(evdns_base, |
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DNS_OPTION_NAMESERVERS, o.resolv_conf); |
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if (res < 0) { |
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fprintf(stderr, "Couldn't configure nameservers"); |
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return 1; |
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} |
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} |
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printf("EVUTIL_AI_CANONNAME in example = %d\n", EVUTIL_AI_CANONNAME); |
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for (; optind < c; ++optind) { |
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if (o.reverse) { |
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struct in_addr addr; |
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if (evutil_inet_pton(AF_INET, v[optind], &addr)!=1) { |
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fprintf(stderr, "Skipping non-IP %s\n", v[optind]); |
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continue; |
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} |
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fprintf(stderr, "resolving %s...\n",v[optind]); |
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evdns_base_resolve_reverse(evdns_base, &addr, 0, main_callback, v[optind]); |
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} else if (o.use_getaddrinfo) { |
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struct evutil_addrinfo hints; |
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memset(&hints, 0, sizeof(hints)); |
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hints.ai_family = PF_UNSPEC; |
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hints.ai_protocol = IPPROTO_TCP; |
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hints.ai_flags = EVUTIL_AI_CANONNAME; |
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fprintf(stderr, "resolving (fwd) %s...\n",v[optind]); |
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evdns_getaddrinfo(evdns_base, v[optind], NULL, &hints, |
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gai_callback, v[optind]); |
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} else { |
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fprintf(stderr, "resolving (fwd) %s...\n",v[optind]); |
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evdns_base_resolve_ipv4(evdns_base, v[optind], 0, main_callback, v[optind]); |
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} |
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} |
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fflush(stdout); |
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event_base_dispatch(event_base); |
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return 0; |
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} |
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