111 lines
2.8 KiB
C++
111 lines
2.8 KiB
C++
#include <event2/dns.h>
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#include <event2/util.h>
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#include <event2/event.h>
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#include <sys/socket.h>
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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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#include <assert.h>
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int n_pending_requests = 0;
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struct event_base *base = NULL;
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struct user_data {
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char *name; /* the name we're resolving */
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int idx; /* its position on the command line */
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};
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void callback(int errcode, struct evutil_addrinfo *addr, void *ptr)
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{
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struct user_data *data = (user_data*) ptr;
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const char *name = data->name;
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if (errcode) {
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printf("%d. %s -> %s\n", data->idx, name, evutil_gai_strerror(errcode));
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} else {
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struct evutil_addrinfo *ai;
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printf("%d. %s", data->idx, name);
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if (addr->ai_canonname)
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printf(" [%s]", addr->ai_canonname);
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puts("");
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for (ai = addr; ai; ai = ai->ai_next) {
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char buf[128];
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const char *s = NULL;
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if (ai->ai_family == AF_INET) {
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struct sockaddr_in *sin = (struct sockaddr_in *)ai->ai_addr;
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s = evutil_inet_ntop(AF_INET, &sin->sin_addr, buf, 128);
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} else if (ai->ai_family == AF_INET6) {
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struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ai->ai_addr;
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s = evutil_inet_ntop(AF_INET6, &sin6->sin6_addr, buf, 128);
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}
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if (s)
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printf(" -> %s\n", s);
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}
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evutil_freeaddrinfo(addr);
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}
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free(data->name);
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free(data);
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if (--n_pending_requests == 0)
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event_base_loopexit(base, NULL);
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}
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/* Take a list of domain names from the command line and resolve them in
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* parallel. */
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int main(int argc, char **argv)
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{
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int i;
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struct evdns_base *dnsbase;
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if (argc == 1) {
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puts("No addresses given.");
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return 0;
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}
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base = event_base_new();
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if (!base)
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return 1;
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dnsbase = evdns_base_new(base, 1);
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if (!dnsbase)
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return 2;
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for (i = 1; i < argc; ++i) {
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struct evutil_addrinfo hints;
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struct evdns_getaddrinfo_request *req;
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struct user_data *user_data;
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memset(&hints, 0, sizeof(hints));
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hints.ai_family = AF_UNSPEC;
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hints.ai_flags = EVUTIL_AI_CANONNAME;
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/* Unless we specify a socktype, we'll get at least two entries for
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* each address: one for TCP and one for UDP. That's not what we
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* want. */
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hints.ai_socktype = SOCK_STREAM;
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hints.ai_protocol = IPPROTO_UDP;
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if (!(user_data = (struct user_data*) malloc(sizeof(struct user_data)))) {
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perror("malloc");
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exit(1);
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}
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if (!(user_data->name = strdup(argv[i]))) {
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perror("strdup");
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exit(1);
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}
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user_data->idx = i;
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++n_pending_requests;
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req = evdns_getaddrinfo(dnsbase, argv[i], "_ts3" /* no service name given */, &hints, callback, user_data);
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if (req == NULL) {
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printf(" [request for %s returned immediately]\n", argv[i]);
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/* No need to free user_data or decrement n_pending_requests; that
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* happened in the callback. */
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}
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}
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if (n_pending_requests)
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event_base_dispatch(base);
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evdns_base_free(dnsbase, 0);
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event_base_free(base);
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return 0;
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}
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