2 * Copyright (c) 2008 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Simon 'corecode' Schubert <corecode@fs.ei.tum.de>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #include <sys/types.h>
36 #include <netinet/in.h>
37 #include <arpa/inet.h>
38 #include <arpa/nameser.h>
48 sort_pref(const void *a, const void *b)
50 const struct mx_hostentry *ha = a, *hb = b;
53 /* sort increasing by preference primarily */
54 v = ha->pref - hb->pref;
58 /* sort PF_INET6 before PF_INET */
59 v = - (ha->ai.ai_family - hb->ai.ai_family);
64 add_host(int pref, const char *host, int port, struct mx_hostentry **he, size_t *ps)
66 struct addrinfo hints, *res, *res0 = NULL;
68 struct mx_hostentry *p;
70 const int count_inc = 10;
75 memset(&hints, 0, sizeof(hints));
76 hints.ai_family = PF_UNSPEC;
77 hints.ai_socktype = SOCK_STREAM;
78 hints.ai_protocol = IPPROTO_TCP;
80 snprintf(servname, sizeof(servname), "%d", port);
81 err = getaddrinfo(host, servname, &hints, &res0);
85 for (res = res0; res != NULL; res = res->ai_next) {
86 if (*ps + 1 >= roundup(*ps, count_inc)) {
87 size_t newsz = roundup(*ps + 2, count_inc);
88 *he = reallocf(*he, newsz * sizeof(**he));
94 strlcpy(p->host, host, sizeof(p->host));
98 bcopy(res->ai_addr, &p->sa, p->ai.ai_addrlen);
100 getnameinfo((struct sockaddr *)&p->sa, p->ai.ai_addrlen,
101 p->addr, sizeof(p->addr),
102 NULL, 0, NI_NUMERICHOST);
108 return (*ps - onhosts);
117 dns_get_mx_list(const char *host, int port, struct mx_hostentry **he, int no_mx)
119 char outname[MAXDNAME];
122 const char *searchhost;
125 struct mx_hostentry *hosts = NULL;
146 err = res_search(searchhost, ns_c_in, ns_t_mx, ans, anssz);
151 * Host exists, but no MX (or CNAME) entry.
152 * Not an error, use host name instead.
156 /* transient error */
166 if (!ns_initparse(ans, anssz, &msg))
169 switch (ns_msg_getflag(msg, ns_f_rcode)) {
178 for (i = 0; i < ns_msg_count(msg, ns_s_an); i++) {
179 if (ns_parserr(&msg, ns_s_an, i, &rr))
182 cp = (const char *)ns_rr_rdata(rr);
184 switch (ns_rr_type(rr)) {
188 err = ns_name_uncompress(ns_msg_base(msg), ns_msg_end(msg),
189 cp, outname, sizeof(outname));
193 add_host(pref, outname, port, &hosts, &nhosts);
197 err = ns_name_uncompress(ns_msg_base(msg), ns_msg_end(msg),
198 cp, outname, sizeof(outname));
202 /* Prevent a CNAME loop */
203 if (cname_recurse++ > 10)
206 searchhost = outname;
230 * If we didn't find any MX, use the hostname instead.
233 add_host(0, searchhost, port, &hosts, &nhosts);
235 qsort(hosts, nhosts, sizeof(*hosts), sort_pref);
240 *hosts[nhosts].host = 0;
258 main(int argc, char **argv)
260 struct mx_hostentry *he, *p;
263 err = dns_get_mx_list(argv[1], 53, &he, 0);
267 for (p = he; *p->host != 0; p++) {
268 printf("%d\t%s\t%s\n", p->pref, p->host, p->addr);