1 /* dns-stuff.c - DNS related code including CERT RR (rfc-4398)
2 * Copyright (C) 2003, 2005, 2006, 2009 Free Software Foundation, Inc.
3 * Copyright (C) 2005, 2006, 2009, 2015. 2016 Werner Koch
5 * This file is part of GnuPG.
7 * This file is free software; you can redistribute it and/or modify
8 * it under the terms of either
10 * - the GNU Lesser General Public License as published by the Free
11 * Software Foundation; either version 3 of the License, or (at
12 * your option) any later version.
16 * - the GNU General Public License as published by the Free
17 * Software Foundation; either version 2 of the License, or (at
18 * your option) any later version.
20 * or both in parallel, as here.
22 * This file is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
27 * You should have received a copy of the GNU General Public License
28 * along with this program; if not, see <https://www.gnu.org/licenses/>.
32 #include <sys/types.h>
33 #ifdef HAVE_W32_SYSTEM
34 # define WIN32_LEAN_AND_MEAN
35 # ifdef HAVE_WINSOCK2_H
36 # include <winsock2.h>
39 # include <iphlpapi.h>
41 # if HAVE_SYSTEM_RESOLVER
42 # include <netinet/in.h>
43 # include <arpa/nameser.h>
52 /* William Ahern's DNS library, included as a source copy. */
57 /* dns.c has a dns_p_free but it is not exported. We use our own
58 * wrapper here so that we do not accidentally use xfree which would
59 * be wrong for dns.c allocated data. */
60 #define dns_free(a) free ((a))
63 #ifdef WITHOUT_NPTH /* Give the Makefile a chance to build without Pth. */
70 #include "./dirmngr-err.h"
73 #include "dns-stuff.h"
76 # define my_unprotect() npth_unprotect ()
77 # define my_protect() npth_protect ()
79 # define my_unprotect() do { } while(0)
80 # define my_protect() do { } while(0)
83 /* We allow the use of 0 instead of AF_UNSPEC - check this assumption. */
85 # error AF_UNSPEC does not have the value 0
88 /* Windows does not support the AI_ADDRCONFIG flag - use zero instead. */
90 # define AI_ADDRCONFIG 0
93 /* Not every installation has gotten around to supporting SRVs or
102 /* The standard SOCKS and TOR ports. */
103 #define SOCKS_PORT 1080
104 #define TOR_PORT 9050
105 #define TOR_PORT2 9150 /* (Used by the Tor browser) */
108 /* The default nameserver used in Tor mode. */
109 #define DEFAULT_NAMESERVER "8.8.8.8"
111 /* The default timeout in seconds for libdns requests. */
112 #define DEFAULT_TIMEOUT 30
115 /* Two flags to enable verbose and debug mode. */
116 static int opt_verbose;
117 static int opt_debug;
119 /* The timeout in seconds for libdns requests. */
120 static int opt_timeout;
122 /* If set force the use of the standard resolver. */
123 static int standard_resolver;
125 /* If set use recursive resolver when available. */
126 static int recursive_resolver;
128 /* If set Tor mode shall be used. */
131 /* A string with the nameserver IP address used with Tor.
132 (40 should be sufficient for v6 but we add some extra for a scope.) */
133 static char tor_nameserver[40+20];
135 /* Two strings to hold the credentials presented to Tor. */
136 static char tor_socks_user[30];
137 static char tor_socks_password[20];
141 /* Libdns gobal data. */
144 struct dns_resolv_conf *resolv_conf;
145 struct dns_hosts *hosts;
146 struct dns_hints *hints;
148 struct sockaddr_storage socks_host;
151 /* If this flag is set, libdns shall be reinited for the next use. */
152 static int libdns_reinit_pending;
154 /* The Tor port to be used. */
155 static int libdns_tor_port;
157 #endif /*USE_LIBDNS*/
160 /* Calling this function with YES set to True forces the use of the
161 * standard resolver even if dirmngr has been built with support for
162 * an alternative resolver. */
164 enable_standard_resolver (int yes)
166 standard_resolver = yes;
170 /* Return true if the standard resolver is used. */
172 standard_resolver_p (void)
174 return standard_resolver;
178 /* Calling this function with YES switches libdns into recursive mode.
179 * It has no effect on the standard resolver. */
181 enable_recursive_resolver (int yes)
183 recursive_resolver = yes;
185 libdns_reinit_pending = 1;
190 /* Return true iff the recursive resolver is used. */
192 recursive_resolver_p (void)
195 return !standard_resolver && recursive_resolver;
202 /* Puts this module eternally into Tor mode. When called agained with
203 * NEW_CIRCUIT request a new TOR circuit for the next DNS query. */
205 enable_dns_tormode (int new_circuit)
207 if (!*tor_socks_user || new_circuit)
209 static unsigned int counter;
211 gpgrt_snprintf (tor_socks_user, sizeof tor_socks_user,
212 "dirmngr-%lu", (unsigned long)getpid ());
213 gpgrt_snprintf (tor_socks_password, sizeof tor_socks_password,
221 /* Set verbosity and debug mode for this module. */
223 set_dns_verbose (int verbose, int debug)
225 opt_verbose = verbose;
230 /* Set the timeout for libdns requests to SECONDS. A value of 0 sets
231 * the default timeout and values are capped at 10 minutes. */
233 set_dns_timeout (int seconds)
236 seconds = DEFAULT_TIMEOUT;
237 else if (seconds < 1)
239 else if (seconds > 600)
242 opt_timeout = seconds;
246 /* Change the default IP address of the nameserver to IPADDR. The
247 address needs to be a numerical IP address and will be used for the
248 next DNS query. Note that this is only used in Tor mode. */
250 set_dns_nameserver (const char *ipaddr)
252 strncpy (tor_nameserver, ipaddr? ipaddr : DEFAULT_NAMESERVER,
253 sizeof tor_nameserver -1);
254 tor_nameserver[sizeof tor_nameserver -1] = 0;
256 libdns_reinit_pending = 1;
257 libdns_tor_port = 0; /* Start again with the default port. */
262 /* Free an addressinfo linked list as returned by resolve_dns_name. */
264 free_dns_addrinfo (dns_addrinfo_t ai)
268 dns_addrinfo_t next = ai->next;
275 #ifndef HAVE_W32_SYSTEM
276 /* Return H_ERRNO mapped to a gpg-error code. Will never return 0. */
278 get_h_errno_as_gpg_error (void)
284 case HOST_NOT_FOUND: ec = GPG_ERR_NO_NAME; break;
285 case TRY_AGAIN: ec = GPG_ERR_TRY_LATER; break;
286 case NO_RECOVERY: ec = GPG_ERR_SERVER_FAILED; break;
287 case NO_DATA: ec = GPG_ERR_NO_DATA; break;
288 default: ec = GPG_ERR_UNKNOWN_ERRNO; break;
290 return gpg_error (ec);
292 #endif /*!HAVE_W32_SYSTEM*/
295 map_eai_to_gpg_error (int ec)
301 case EAI_AGAIN: err = gpg_error (GPG_ERR_EAGAIN); break;
302 case EAI_BADFLAGS: err = gpg_error (GPG_ERR_INV_FLAG); break;
303 case EAI_FAIL: err = gpg_error (GPG_ERR_SERVER_FAILED); break;
304 case EAI_MEMORY: err = gpg_error (GPG_ERR_ENOMEM); break;
306 case EAI_NODATA: err = gpg_error (GPG_ERR_NO_DATA); break;
308 case EAI_NONAME: err = gpg_error (GPG_ERR_NO_NAME); break;
309 case EAI_SERVICE: err = gpg_error (GPG_ERR_NOT_SUPPORTED); break;
310 case EAI_FAMILY: err = gpg_error (GPG_ERR_EAFNOSUPPORT); break;
311 case EAI_SOCKTYPE: err = gpg_error (GPG_ERR_ESOCKTNOSUPPORT); break;
312 #ifndef HAVE_W32_SYSTEM
313 # ifdef EAI_ADDRFAMILY
314 case EAI_ADDRFAMILY:err = gpg_error (GPG_ERR_EADDRNOTAVAIL); break;
316 case EAI_SYSTEM: err = gpg_error_from_syserror (); break;
318 default: err = gpg_error (GPG_ERR_UNKNOWN_ERRNO); break;
326 libdns_error_to_gpg_error (int serr)
332 case 0: ec = 0; break;
334 case DNS_ENOBUFS: ec = GPG_ERR_BUFFER_TOO_SHORT; break;
335 case DNS_EILLEGAL: ec = GPG_ERR_INV_OBJ; break;
336 case DNS_EORDER: ec = GPG_ERR_INV_ORDER; break;
337 case DNS_ESECTION: ec = GPG_ERR_DNS_SECTION; break;
338 case DNS_EUNKNOWN: ec = GPG_ERR_DNS_UNKNOWN; break;
339 case DNS_EADDRESS: ec = GPG_ERR_DNS_ADDRESS; break;
340 case DNS_ENOQUERY: ec = GPG_ERR_DNS_NO_QUERY; break;
341 case DNS_ENOANSWER:ec = GPG_ERR_DNS_NO_ANSWER; break;
342 case DNS_EFETCHED: ec = GPG_ERR_ALREADY_FETCHED; break;
343 case DNS_ESERVICE: ec = GPG_ERR_NOT_SUPPORTED; break;
344 case DNS_ENONAME: ec = GPG_ERR_NO_NAME; break;
345 case DNS_EFAIL: ec = GPG_ERR_SERVER_FAILED; break;
346 case DNS_ECONNFIN: ec = GPG_ERR_DNS_CLOSED; break;
347 case DNS_EVERIFY: ec = GPG_ERR_DNS_VERIFY; break;
351 ec = gpg_err_code_from_errno (serr);
353 ec = GPG_ERR_DNS_UNKNOWN;
356 return gpg_error (ec);
358 #endif /*USE_LIBDNS*/
362 /* Initialize libdns. Returns 0 on success; prints a diagnostic and
363 * returns an error code on failure. */
372 if (libdns.resolv_conf)
373 return 0; /* Already initialized. */
375 memset (&ld, 0, sizeof ld);
377 ld.resolv_conf = dns_resconf_open (&derr);
380 err = libdns_error_to_gpg_error (derr);
381 log_error ("failed to allocate DNS resconf object: %s\n",
388 if (!*tor_nameserver)
389 set_dns_nameserver (NULL);
391 if (!libdns_tor_port)
392 libdns_tor_port = TOR_PORT;
394 cfgstr = xtryasprintf ("[%s]:53", tor_nameserver);
396 err = gpg_error_from_syserror ();
398 err = libdns_error_to_gpg_error
399 (dns_resconf_pton (&ld.resolv_conf->nameserver[0], cfgstr));
401 log_error ("failed to set nameserver '%s': %s\n",
402 cfgstr, gpg_strerror (err));
406 ld.resolv_conf->options.tcp = DNS_RESCONF_TCP_SOCKS;
409 cfgstr = xtryasprintf ("[%s]:%d", "127.0.0.1", libdns_tor_port);
411 err = gpg_error_from_syserror ();
413 err = libdns_error_to_gpg_error
414 (dns_resconf_pton (&ld.socks_host, cfgstr));
417 log_error ("failed to set socks server '%s': %s\n",
418 cfgstr, gpg_strerror (err));
424 #ifdef HAVE_W32_SYSTEM
431 ninfo = xtrymalloc (ninfo_len);
434 err = gpg_error_from_syserror ();
438 if (GetNetworkParams (ninfo, &ninfo_len))
440 log_error ("GetNetworkParms failed: %s\n", w32_strerror (-1));
441 err = gpg_error (GPG_ERR_GENERAL);
446 for (idx=0, pip = &(ninfo->DnsServerList);
447 pip && idx < DIM (ld.resolv_conf->nameserver);
451 log_debug ("dns: dnsserver[%d] '%s'\n", idx, pip->IpAddress.String);
452 err = libdns_error_to_gpg_error
453 (dns_resconf_pton (&ld.resolv_conf->nameserver[idx],
454 pip->IpAddress.String));
456 log_error ("failed to set nameserver[%d] '%s': %s\n",
457 idx, pip->IpAddress.String, gpg_strerror (err));
466 fname = "/etc/resolv.conf";
467 err = libdns_error_to_gpg_error
468 (dns_resconf_loadpath (ld.resolv_conf, fname));
471 log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
475 fname = "/etc/nsswitch.conf";
476 err = libdns_error_to_gpg_error
477 (dns_nssconf_loadpath (ld.resolv_conf, fname));
480 log_error ("failed to load '%s': %s\n", fname, gpg_strerror (err));
481 /* not fatal, nsswitch.conf is not used on all systems; assume
482 * classic behavior instead. Our dns library states "bf" which tries
483 * DNS then Files, which is not classic; FreeBSD
484 * /usr/src/lib/libc/net/gethostnamadr.c defines default_src[] which
485 * is Files then DNS, which is. */
487 log_debug ("dns: fallback resolution order, files then DNS\n");
488 ld.resolv_conf->lookup[0] = 'f';
489 ld.resolv_conf->lookup[1] = 'b';
490 ld.resolv_conf->lookup[2] = '\0';
491 err = GPG_ERR_NO_ERROR;
497 ld.hosts = dns_hosts_open (&derr);
500 log_error ("failed to load hosts file: %s\n", gpg_strerror (err));
501 err = libdns_error_to_gpg_error (derr);
505 /* dns_hints_local for stub mode, dns_hints_root for recursive. */
506 ld.hints = (recursive_resolver
507 ? dns_hints_root (ld.resolv_conf, &derr)
508 : dns_hints_local (ld.resolv_conf, &derr));
511 log_error ("failed to load DNS hints: %s\n", gpg_strerror (err));
512 err = libdns_error_to_gpg_error (derr);
516 /* All fine. Make the data global. */
520 log_debug ("dns: libdns initialized%s\n", tor_mode?" (tor mode)":"");
526 #endif /*USE_LIBDNS*/
530 /* Deinitialize libdns. */
536 if (!libdns.resolv_conf)
537 return; /* Not initialized. */
540 memset (&libdns, 0, sizeof libdns);
541 dns_hints_close (ld.hints);
542 dns_hosts_close (ld.hosts);
543 dns_resconf_close (ld.resolv_conf);
545 #endif /*USE_LIBDNS*/
548 /* SIGHUP action handler for this module. With FORCE set objects are
549 * all immediately released. */
551 reload_dns_stuff (int force)
557 libdns_reinit_pending = 0;
561 libdns_reinit_pending = 1;
562 libdns_tor_port = 0; /* Start again with the default port. */
572 * Initialize libdns if needed and open a dns_resolver context.
573 * Returns 0 on success and stores the new context at R_RES. On
574 * failure an error code is returned and NULL stored at R_RES.
577 libdns_res_open (struct dns_resolver **r_res)
580 struct dns_resolver *res;
585 if (libdns_reinit_pending)
587 libdns_reinit_pending = 0;
591 err = libdns_init ();
598 res = dns_res_open (libdns.resolv_conf, libdns.hosts, libdns.hints, NULL,
599 dns_opts (.socks_host = &libdns.socks_host,
600 .socks_user = tor_socks_user,
601 .socks_password = tor_socks_password ),
604 return libdns_error_to_gpg_error (derr);
609 #endif /*USE_LIBDNS*/
613 /* Helper to test whether we need to try again after having switched
616 libdns_switch_port_p (gpg_error_t err)
618 if (tor_mode && gpg_err_code (err) == GPG_ERR_ECONNREFUSED
619 && libdns_tor_port == TOR_PORT)
621 /* Switch port and try again. */
623 log_debug ("dns: switching from SOCKS port %d to %d\n",
624 TOR_PORT, TOR_PORT2);
625 libdns_tor_port = TOR_PORT2;
626 libdns_reinit_pending = 1;
631 #endif /*USE_LIBDNS*/
635 /* Wrapper around dns_res_submit. */
637 libdns_res_submit (struct dns_resolver *res, const char *qname,
638 enum dns_type qtype, enum dns_class qclass)
640 return libdns_error_to_gpg_error (dns_res_submit (res, qname, qtype, qclass));
642 #endif /*USE_LIBDNS*/
646 /* Standard event handling loop. */
648 libdns_res_wait (struct dns_resolver *res)
652 while ((err = libdns_error_to_gpg_error (dns_res_check (res)))
653 && gpg_err_code (err) == GPG_ERR_EAGAIN)
655 if (dns_res_elapsed (res) > opt_timeout)
657 err = gpg_error (GPG_ERR_DNS_TIMEOUT);
662 dns_res_poll (res, 1);
668 #endif /*USE_LIBDNS*/
673 resolve_name_libdns (const char *name, unsigned short port,
674 int want_family, int want_socktype,
675 dns_addrinfo_t *r_dai, char **r_canonname)
678 dns_addrinfo_t daihead = NULL;
680 struct dns_resolver *res = NULL;
681 struct dns_addrinfo *ai = NULL;
682 struct addrinfo hints;
683 struct addrinfo *ent;
685 char *portstr = NULL;
692 memset (&hints, 0, sizeof hints);
693 hints.ai_family = want_family;
694 hints.ai_socktype = want_socktype;
695 hints.ai_flags = AI_ADDRCONFIG;
697 hints.ai_flags |= AI_CANONNAME;
698 if (is_ip_address (name))
699 hints.ai_flags |= AI_NUMERICHOST;
703 snprintf (portstr_, sizeof portstr_, "%hu", port);
707 err = libdns_res_open (&res);
711 ai = dns_ai_open (name, portstr, 0, &hints, res, &derr);
714 err = libdns_error_to_gpg_error (derr);
718 /* Loop over all records. */
721 err = libdns_error_to_gpg_error (dns_ai_nextent (&ent, ai));
722 if (gpg_err_code (err) == GPG_ERR_ENOENT)
725 err = 0; /* We got some results, we're good. */
728 if (gpg_err_code (err) == GPG_ERR_EAGAIN)
730 if (dns_ai_elapsed (ai) > opt_timeout)
732 err = gpg_error (GPG_ERR_DNS_TIMEOUT);
744 if (r_canonname && ! *r_canonname && ent && ent->ai_canonname)
746 *r_canonname = xtrystrdup (ent->ai_canonname);
749 err = gpg_error_from_syserror ();
752 /* Libdns appends the root zone part which is problematic
753 * for most other functions - strip it. */
754 if (**r_canonname && (*r_canonname)[strlen (*r_canonname)-1] == '.')
755 (*r_canonname)[strlen (*r_canonname)-1] = 0;
758 dai = xtrymalloc (sizeof *dai + ent->ai_addrlen -1);
761 err = gpg_error_from_syserror ();
765 dai->family = ent->ai_family;
766 dai->socktype = ent->ai_socktype;
767 dai->protocol = ent->ai_protocol;
768 dai->addrlen = ent->ai_addrlen;
769 memcpy (dai->addr, ent->ai_addr, ent->ai_addrlen);
784 xfree (*r_canonname);
787 free_dns_addrinfo (daihead);
794 #endif /*USE_LIBDNS*/
797 /* Resolve a name using the standard system function. */
799 resolve_name_standard (const char *name, unsigned short port,
800 int want_family, int want_socktype,
801 dns_addrinfo_t *r_dai, char **r_canonname)
804 dns_addrinfo_t daihead = NULL;
806 struct addrinfo *aibuf = NULL;
807 struct addrinfo hints, *ai;
815 memset (&hints, 0, sizeof hints);
816 hints.ai_family = want_family;
817 hints.ai_socktype = want_socktype;
818 hints.ai_flags = AI_ADDRCONFIG;
820 hints.ai_flags |= AI_CANONNAME;
821 if (is_ip_address (name))
822 hints.ai_flags |= AI_NUMERICHOST;
825 snprintf (portstr, sizeof portstr, "%hu", port);
829 /* We can't use the the AI_IDN flag because that does the conversion
830 using the current locale. However, GnuPG always used UTF-8. To
831 support IDN we would need to make use of the libidn API. */
832 ret = getaddrinfo (name, *portstr? portstr : NULL, &hints, &aibuf);
836 err = map_eai_to_gpg_error (ret);
837 if (gpg_err_code (err) == GPG_ERR_NO_NAME)
839 /* There seems to be a bug in the glibc getaddrinfo function
840 if the CNAME points to a long list of A and AAAA records
841 in which case the function return NO_NAME. Let's do the
842 CNAME redirection again. */
845 if (get_dns_cname (name, &cname))
846 goto leave; /* Still no success. */
848 ret = getaddrinfo (cname, *portstr? portstr : NULL, &hints, &aibuf);
853 err = map_eai_to_gpg_error (ret);
856 err = 0; /* Yep, now it worked. */
862 if (r_canonname && aibuf && aibuf->ai_canonname)
864 *r_canonname = xtrystrdup (aibuf->ai_canonname);
867 err = gpg_error_from_syserror ();
872 for (ai = aibuf; ai; ai = ai->ai_next)
874 if (ai->ai_family != AF_INET6 && ai->ai_family != AF_INET)
877 dai = xtrymalloc (sizeof *dai + ai->ai_addrlen - 1);
878 dai->family = ai->ai_family;
879 dai->socktype = ai->ai_socktype;
880 dai->protocol = ai->ai_protocol;
881 dai->addrlen = ai->ai_addrlen;
882 memcpy (dai->addr, ai->ai_addr, ai->ai_addrlen);
889 freeaddrinfo (aibuf);
894 xfree (*r_canonname);
897 free_dns_addrinfo (daihead);
905 /* This a wrapper around getaddrinfo with slightly different semantics.
906 NAME is the name to resolve.
907 PORT is the requested port or 0.
908 WANT_FAMILY is either 0 (AF_UNSPEC), AF_INET6, or AF_INET4.
909 WANT_SOCKETTYPE is either SOCK_STREAM or SOCK_DGRAM.
911 On success the result is stored in a linked list with the head
912 stored at the address R_AI; the caller must call gpg_addrinfo_free
913 on this. If R_CANONNAME is not NULL the official name of the host
914 is stored there as a malloced string; if that name is not available
917 resolve_dns_name (const char *name, unsigned short port,
918 int want_family, int want_socktype,
919 dns_addrinfo_t *r_ai, char **r_canonname)
924 if (!standard_resolver)
926 err = resolve_name_libdns (name, port, want_family, want_socktype,
928 if (err && libdns_switch_port_p (err))
929 err = resolve_name_libdns (name, port, want_family, want_socktype,
933 #endif /*USE_LIBDNS*/
934 err = resolve_name_standard (name, port, want_family, want_socktype,
937 log_debug ("dns: resolve_dns_name(%s): %s\n", name, gpg_strerror (err));
943 /* Resolve an address using libdns. */
945 resolve_addr_libdns (const struct sockaddr *addr, int addrlen,
946 unsigned int flags, char **r_name)
949 char host[DNS_D_MAXNAME + 1];
950 struct dns_resolver *res = NULL;
951 struct dns_packet *ans = NULL;
957 /* First we turn ADDR into a DNS name (with ".arpa" suffix). */
959 if (addr->sa_family == AF_INET6)
961 const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *)addr;
962 if (!dns_aaaa_arpa (host, sizeof host, (void*)&a6->sin6_addr))
963 err = gpg_error (GPG_ERR_INV_OBJ);
965 else if (addr->sa_family == AF_INET)
967 const struct sockaddr_in *a4 = (const struct sockaddr_in *)addr;
968 if (!dns_a_arpa (host, sizeof host, (void*)&a4->sin_addr))
969 err = gpg_error (GPG_ERR_INV_OBJ);
972 err = gpg_error (GPG_ERR_EAFNOSUPPORT);
977 err = libdns_res_open (&res);
981 err = libdns_res_submit (res, host, DNS_T_PTR, DNS_C_IN);
985 err = libdns_res_wait (res);
989 ans = dns_res_fetch (res, &derr);
992 err = libdns_error_to_gpg_error (derr);
996 /* Check the rcode. */
997 switch (dns_p_rcode (ans))
1001 case DNS_RC_NXDOMAIN:
1002 err = gpg_error (GPG_ERR_NO_NAME);
1005 err = GPG_ERR_SERVER_FAILED;
1009 /* Parse the result. */
1013 struct dns_rr_i rri;
1015 memset (&rri, 0, sizeof rri);
1016 dns_rr_i_init (&rri, ans);
1017 rri.section = DNS_S_ALL & ~DNS_S_QD;
1019 rri.type = DNS_T_PTR;
1021 if (!dns_rr_grep (&rr, 1, &rri, ans, &derr))
1023 err = gpg_error (GPG_ERR_NOT_FOUND);
1027 err = libdns_error_to_gpg_error (dns_ptr_parse (&ptr, &rr, ans));
1032 *r_name = xtrystrdup (ptr.host);
1035 err = gpg_error_from_syserror ();
1038 /* Libdns appends the root zone part which is problematic
1039 * for most other functions - strip it. */
1040 if (**r_name && (*r_name)[strlen (*r_name)-1] == '.')
1041 (*r_name)[strlen (*r_name)-1] = 0;
1043 else /* GPG_ERR_NO_NAME */
1050 buflen = sizeof ptr.host;
1053 if (addr->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
1058 ec = getnameinfo (addr, addrlen, p, buflen, NULL, 0, NI_NUMERICHOST);
1061 err = map_eai_to_gpg_error (ec);
1064 if (addr->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
1065 strcat (buffer, "]");
1070 dns_res_close (res);
1073 #endif /*USE_LIBDNS*/
1076 /* Resolve an address using the standard system function. */
1078 resolve_addr_standard (const struct sockaddr *addr, int addrlen,
1079 unsigned int flags, char **r_name)
1088 buflen = NI_MAXHOST;
1089 buffer = xtrymalloc (buflen + 2 + 1);
1091 return gpg_error_from_syserror ();
1093 if ((flags & DNS_NUMERICHOST) || tor_mode)
1096 ec = getnameinfo (addr, addrlen, buffer, buflen, NULL, 0, NI_NAMEREQD);
1098 if (!ec && *buffer == '[')
1099 ec = EAI_FAIL; /* A name may never start with a bracket. */
1100 else if (ec == EAI_NONAME)
1103 if (addr->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
1108 ec = getnameinfo (addr, addrlen, p, buflen, NULL, 0, NI_NUMERICHOST);
1109 if (!ec && addr->sa_family == AF_INET6 && (flags & DNS_WITHBRACKET))
1110 strcat (buffer, "]");
1114 err = map_eai_to_gpg_error (ec);
1117 p = xtryrealloc (buffer, strlen (buffer)+1);
1119 err = gpg_error_from_syserror ();
1136 /* A wrapper around getnameinfo. */
1138 resolve_dns_addr (const struct sockaddr *addr, int addrlen,
1139 unsigned int flags, char **r_name)
1144 /* Note that we divert to the standard resolver for NUMERICHOST. */
1145 if (!standard_resolver && !(flags & DNS_NUMERICHOST))
1147 err = resolve_addr_libdns (addr, addrlen, flags, r_name);
1148 if (err && libdns_switch_port_p (err))
1149 err = resolve_addr_libdns (addr, addrlen, flags, r_name);
1152 #endif /*USE_LIBDNS*/
1153 err = resolve_addr_standard (addr, addrlen, flags, r_name);
1156 log_debug ("dns: resolve_dns_addr(): %s\n", gpg_strerror (err));
1161 /* Check whether NAME is an IP address. Returns a true if it is
1162 * either an IPv6 or a IPv4 numerical address. The actual return
1163 * values can also be used to identify whether it is v4 or v6: The
1164 * true value will surprisingly be 4 for IPv4 and 6 for IPv6. */
1166 is_ip_address (const char *name)
1169 int ndots, dblcol, n;
1172 return 6; /* yes: A legal DNS name may not contain this character;
1173 this mut be bracketed v6 address. */
1175 return 0; /* No. A leading dot is not a valid IP address. */
1177 /* Check whether this is a v6 address. */
1178 ndots = n = dblcol = 0;
1179 for (s=name; *s; s++)
1188 return 0; /* No: Only one "::" allowed. */
1197 else if (!strchr ("0123456789abcdefABCDEF", *s))
1198 return 0; /* No: Not a hex digit. */
1200 return 0; /* To many digits in a group. */
1203 return 0; /* No: Too many colons. */
1205 return 6; /* Yes: At least 2 colons indicate an v6 address. */
1208 /* Check whether it is legacy IP address. */
1210 for (s=name; *s; s++)
1215 return 0; /* No: Douple dot. */
1216 if (atoi (s+1) > 255)
1217 return 0; /* No: Ipv4 byte value too large. */
1221 else if (!strchr ("0123456789", *s))
1222 return 0; /* No: Not a digit. */
1224 return 0; /* No: More than 3 digits. */
1226 return (ndots == 3)? 4 : 0;
1230 /* Return true if NAME is an onion address. */
1232 is_onion_address (const char *name)
1236 len = name? strlen (name) : 0;
1237 if (len < 8 || strcmp (name + len - 6, ".onion"))
1239 /* Note that we require at least 2 characters before the suffix. */
1240 return 1; /* Yes. */
1244 /* libdns version of get_dns_cert. */
1247 get_dns_cert_libdns (const char *name, int want_certtype,
1248 void **r_key, size_t *r_keylen,
1249 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1252 struct dns_resolver *res = NULL;
1253 struct dns_packet *ans = NULL;
1255 struct dns_rr_i rri;
1256 char host[DNS_D_MAXNAME + 1];
1260 /* Get the query type from WANT_CERTTYPE (which in general indicates
1261 * the subtype we want). */
1262 qtype = (want_certtype < DNS_CERTTYPE_RRBASE
1264 : (want_certtype - DNS_CERTTYPE_RRBASE));
1267 err = libdns_res_open (&res);
1271 if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
1273 err = gpg_error (GPG_ERR_ENAMETOOLONG);
1277 err = libdns_res_submit (res, name, qtype, DNS_C_IN);
1281 err = libdns_res_wait (res);
1285 ans = dns_res_fetch (res, &derr);
1288 err = libdns_error_to_gpg_error (derr);
1292 /* Check the rcode. */
1293 switch (dns_p_rcode (ans))
1295 case DNS_RC_NOERROR: break;
1296 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
1297 default: err = GPG_ERR_SERVER_FAILED; break;
1302 memset (&rri, 0, sizeof rri);
1303 dns_rr_i_init (&rri, ans);
1304 rri.section = DNS_S_ALL & ~DNS_S_QD;
1308 err = gpg_error (GPG_ERR_NOT_FOUND);
1309 while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
1311 unsigned char *rp = ans->data + rr.rd.p;
1312 unsigned short len = rr.rd.len;
1317 /* Definitely too short - skip. */
1319 else if (want_certtype >= DNS_CERTTYPE_RRBASE
1320 && rr.type == (want_certtype - DNS_CERTTYPE_RRBASE)
1323 *r_key = xtrymalloc (len);
1325 err = gpg_error_from_syserror ();
1328 memcpy (*r_key, rp, len);
1334 else if (want_certtype >= DNS_CERTTYPE_RRBASE)
1336 /* We did not found the requested RR - skip. */
1338 else if (rr.type == T_CERT && len > 5)
1340 /* We got a CERT type. */
1341 subtype = buf16_to_u16 (rp);
1344 /* Skip the CERT key tag and algo which we don't need. */
1347 if (want_certtype && want_certtype != subtype)
1348 ; /* Not the requested subtype - skip. */
1349 else if (subtype == DNS_CERTTYPE_PGP && len && r_key && r_keylen)
1352 *r_key = xtrymalloc (len);
1354 err = gpg_error_from_syserror ();
1357 memcpy (*r_key, rp, len);
1363 else if (subtype == DNS_CERTTYPE_IPGP
1364 && len && len < 1023 && len >= rp[0] + 1)
1370 *r_fpr = xtrymalloc (*r_fprlen);
1373 err = gpg_error_from_syserror ();
1376 memcpy (*r_fpr, rp+1, *r_fprlen);
1381 if (len > *r_fprlen + 1)
1383 *r_url = xtrymalloc (len - (*r_fprlen + 1) + 1);
1386 err = gpg_error_from_syserror ();
1391 memcpy (*r_url, rp + *r_fprlen + 1, len - (*r_fprlen + 1));
1392 (*r_url)[len - (*r_fprlen + 1)] = 0;
1402 /* Unknown subtype or record too short - skip. */
1407 /* Not a requested type - skip. */
1413 dns_res_close (res);
1416 #endif /*USE_LIBDNS*/
1419 /* Standard resolver version of get_dns_cert. */
1421 get_dns_cert_standard (const char *name, int want_certtype,
1422 void **r_key, size_t *r_keylen,
1423 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1425 #ifdef HAVE_SYSTEM_RESOLVER
1427 unsigned char *answer;
1431 /* Allocate a 64k buffer which is the limit for an DNS response. */
1432 answer = xtrymalloc (65536);
1434 return gpg_error_from_syserror ();
1436 err = gpg_error (GPG_ERR_NOT_FOUND);
1437 r = res_query (name, C_IN,
1438 (want_certtype < DNS_CERTTYPE_RRBASE
1440 : (want_certtype - DNS_CERTTYPE_RRBASE)),
1442 /* Not too big, not too small, no errors and at least 1 answer. */
1443 if (r >= sizeof (HEADER) && r <= 65536
1444 && (((HEADER *)(void *) answer)->rcode) == NOERROR
1445 && (count = ntohs (((HEADER *)(void *) answer)->ancount)))
1448 unsigned char *pt, *emsg;
1452 pt = &answer[sizeof (HEADER)];
1454 /* Skip over the query */
1456 rc = dn_skipname (pt, emsg);
1459 err = gpg_error (GPG_ERR_INV_OBJ);
1462 pt += rc + QFIXEDSZ;
1464 /* There are several possible response types for a CERT request.
1465 We're interested in the PGP (a key) and IPGP (a URI) types.
1466 Skip all others. TODO: A key is better than a URI since
1467 we've gone through all this bother to fetch it, so favor that
1468 if we have both PGP and IPGP? */
1470 while (count-- > 0 && pt < emsg)
1472 u16 type, class, dlen, ctype;
1474 rc = dn_skipname (pt, emsg); /* the name we just queried for */
1477 err = gpg_error (GPG_ERR_INV_OBJ);
1483 /* Truncated message? 15 bytes takes us to the point where
1484 we start looking at the ctype. */
1485 if ((emsg - pt) < 15)
1488 type = buf16_to_u16 (pt);
1491 class = buf16_to_u16 (pt);
1501 dlen = buf16_to_u16 (pt);
1504 /* Check the type and parse. */
1505 if (want_certtype >= DNS_CERTTYPE_RRBASE
1506 && type == (want_certtype - DNS_CERTTYPE_RRBASE)
1509 *r_key = xtrymalloc (dlen);
1511 err = gpg_error_from_syserror ();
1514 memcpy (*r_key, pt, dlen);
1520 else if (want_certtype >= DNS_CERTTYPE_RRBASE)
1522 /* We did not found the requested RR. */
1525 else if (type == T_CERT)
1527 /* We got a CERT type. */
1528 ctype = buf16_to_u16 (pt);
1531 /* Skip the CERT key tag and algo which we don't need. */
1536 /* 15 bytes takes us to here */
1537 if (want_certtype && want_certtype != ctype)
1538 ; /* Not of the requested certtype. */
1539 else if (ctype == DNS_CERTTYPE_PGP && dlen && r_key && r_keylen)
1542 *r_key = xtrymalloc (dlen);
1544 err = gpg_error_from_syserror ();
1547 memcpy (*r_key, pt, dlen);
1553 else if (ctype == DNS_CERTTYPE_IPGP
1554 && dlen && dlen < 1023 && dlen >= pt[0] + 1)
1560 *r_fpr = xtrymalloc (*r_fprlen);
1563 err = gpg_error_from_syserror ();
1566 memcpy (*r_fpr, &pt[1], *r_fprlen);
1571 if (dlen > *r_fprlen + 1)
1573 *r_url = xtrymalloc (dlen - (*r_fprlen + 1) + 1);
1576 err = gpg_error_from_syserror ();
1581 memcpy (*r_url, &pt[*r_fprlen + 1],
1582 dlen - (*r_fprlen + 1));
1583 (*r_url)[dlen - (*r_fprlen + 1)] = '\0';
1592 /* No subtype matches, so continue with the next answer. */
1597 /* Not a requested type - might be a CNAME. Try next item. */
1607 #else /*!HAVE_SYSTEM_RESOLVER*/
1610 (void)want_certtype;
1616 return gpg_error (GPG_ERR_NOT_SUPPORTED);
1618 #endif /*!HAVE_SYSTEM_RESOLVER*/
1622 /* Returns 0 on success or an error code. If a PGP CERT record was
1623 found, the malloced data is returned at (R_KEY, R_KEYLEN) and
1624 the other return parameters are set to NULL/0. If an IPGP CERT
1625 record was found the fingerprint is stored as an allocated block at
1626 R_FPR and its length at R_FPRLEN; an URL is is allocated as a
1627 string and returned at R_URL. If WANT_CERTTYPE is 0 this function
1628 returns the first CERT found with a supported type; it is expected
1629 that only one CERT record is used. If WANT_CERTTYPE is one of the
1630 supported certtypes only records with this certtype are considered
1631 and the first found is returned. (R_KEY,R_KEYLEN) are optional. */
1633 get_dns_cert (const char *name, int want_certtype,
1634 void **r_key, size_t *r_keylen,
1635 unsigned char **r_fpr, size_t *r_fprlen, char **r_url)
1648 if (!standard_resolver)
1650 err = get_dns_cert_libdns (name, want_certtype, r_key, r_keylen,
1651 r_fpr, r_fprlen, r_url);
1652 if (err && libdns_switch_port_p (err))
1653 err = get_dns_cert_libdns (name, want_certtype, r_key, r_keylen,
1654 r_fpr, r_fprlen, r_url);
1657 #endif /*USE_LIBDNS*/
1658 err = get_dns_cert_standard (name, want_certtype, r_key, r_keylen,
1659 r_fpr, r_fprlen, r_url);
1662 log_debug ("dns: get_dns_cert(%s): %s\n", name, gpg_strerror (err));
1668 priosort(const void *a,const void *b)
1670 const struct srventry *sa=a,*sb=b;
1671 if(sa->priority>sb->priority)
1673 else if(sa->priority<sb->priority)
1680 /* Libdns based helper for getsrv. Note that it is expected that NULL
1681 * is stored at the address of LIST and 0 is stored at the address of
1685 getsrv_libdns (const char *name, struct srventry **list, unsigned int *r_count)
1688 struct dns_resolver *res = NULL;
1689 struct dns_packet *ans = NULL;
1691 struct dns_rr_i rri;
1692 char host[DNS_D_MAXNAME + 1];
1694 unsigned int srvcount = 0;
1696 err = libdns_res_open (&res);
1700 if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
1702 err = gpg_error (GPG_ERR_ENAMETOOLONG);
1706 err = libdns_res_submit (res, name, DNS_T_SRV, DNS_C_IN);
1710 err = libdns_res_wait (res);
1714 ans = dns_res_fetch (res, &derr);
1717 err = libdns_error_to_gpg_error (derr);
1721 /* Check the rcode. */
1722 switch (dns_p_rcode (ans))
1724 case DNS_RC_NOERROR: break;
1725 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
1726 default: err = GPG_ERR_SERVER_FAILED; break;
1731 memset (&rri, 0, sizeof rri);
1732 dns_rr_i_init (&rri, ans);
1733 rri.section = DNS_S_ALL & ~DNS_S_QD;
1735 rri.type = DNS_T_SRV;
1737 while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
1739 struct dns_srv dsrv;
1740 struct srventry *srv;
1741 struct srventry *newlist;
1743 err = libdns_error_to_gpg_error (dns_srv_parse(&dsrv, &rr, ans));
1747 newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
1750 err = gpg_error_from_syserror ();
1754 memset (&(*list)[srvcount], 0, sizeof(struct srventry));
1755 srv = &(*list)[srvcount];
1757 srv->priority = dsrv.priority;
1758 srv->weight = dsrv.weight;
1759 srv->port = dsrv.port;
1760 mem2str (srv->target, dsrv.target, sizeof srv->target);
1761 /* Libdns appends the root zone part which is problematic for
1762 * most other functions - strip it. */
1763 if (*srv->target && (srv->target)[strlen (srv->target)-1] == '.')
1764 (srv->target)[strlen (srv->target)-1] = 0;
1767 *r_count = srvcount;
1776 dns_res_close (res);
1779 #endif /*USE_LIBDNS*/
1782 /* Standard resolver based helper for getsrv. Note that it is
1783 * expected that NULL is stored at the address of LIST and 0 is stored
1784 * at the address of R_COUNT. */
1786 getsrv_standard (const char *name,
1787 struct srventry **list, unsigned int *r_count)
1789 #ifdef HAVE_SYSTEM_RESOLVER
1791 unsigned char ans[2048];
1794 unsigned char *answer = res.ans;
1795 HEADER *header = res.header;
1796 unsigned char *pt, *emsg;
1799 unsigned int srvcount = 0;
1802 /* Do not allow a query using the standard resolver in Tor mode. */
1804 return gpg_error (GPG_ERR_NOT_ENABLED);
1807 r = res_query (name, C_IN, T_SRV, answer, sizeof res.ans);
1810 return get_h_errno_as_gpg_error ();
1811 if (r < sizeof (HEADER))
1812 return gpg_error (GPG_ERR_SERVER_FAILED);
1813 if (r > sizeof res.ans)
1814 return gpg_error (GPG_ERR_SYSTEM_BUG);
1815 if (header->rcode != NOERROR || !(count=ntohs (header->ancount)))
1816 return gpg_error (GPG_ERR_NO_NAME); /* Error or no record found. */
1819 pt = &answer[sizeof(HEADER)];
1821 /* Skip over the query */
1822 rc = dn_skipname (pt, emsg);
1826 pt += rc + QFIXEDSZ;
1828 while (count-- > 0 && pt < emsg)
1830 struct srventry *srv;
1832 struct srventry *newlist;
1834 newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
1838 memset (&(*list)[srvcount], 0, sizeof(struct srventry));
1839 srv = &(*list)[srvcount];
1842 rc = dn_skipname (pt, emsg); /* The name we just queried for. */
1847 /* Truncated message? */
1851 type = buf16_to_u16 (pt);
1853 /* We asked for SRV and got something else !? */
1857 class = buf16_to_u16 (pt);
1859 /* We asked for IN and got something else !? */
1864 dlen = buf16_to_u16 (pt);
1867 srv->priority = buf16_to_ushort (pt);
1869 srv->weight = buf16_to_ushort (pt);
1871 srv->port = buf16_to_ushort (pt);
1874 /* Get the name. 2782 doesn't allow name compression, but
1875 * dn_expand still works to pull the name out of the packet. */
1876 rc = dn_expand (answer, emsg, pt, srv->target, sizeof srv->target);
1877 if (rc == 1 && srv->target[0] == 0) /* "." */
1886 /* Corrupt packet? */
1891 *r_count = srvcount;
1897 return gpg_error (GPG_ERR_GENERAL);
1899 #else /*!HAVE_SYSTEM_RESOLVER*/
1904 return gpg_error (GPG_ERR_NOT_SUPPORTED);
1906 #endif /*!HAVE_SYSTEM_RESOLVER*/
1910 /* Query a SRV record for SERVICE and PROTO for NAME. If SERVICE is
1911 * NULL, NAME is expected to contain the full query name. Note that
1912 * we do not return NONAME but simply store 0 at R_COUNT. On error an
1913 * error code is returned and 0 stored at R_COUNT. */
1915 get_dns_srv (const char *name, const char *service, const char *proto,
1916 struct srventry **list, unsigned int *r_count)
1919 char *namebuffer = NULL;
1920 unsigned int srvcount;
1927 /* If SERVICE is given construct the query from it and PROTO. */
1930 namebuffer = xtryasprintf ("_%s._%s.%s",
1931 service, proto? proto:"tcp", name);
1934 err = gpg_error_from_syserror ();
1942 if (!standard_resolver)
1944 err = getsrv_libdns (name, list, &srvcount);
1945 if (err && libdns_switch_port_p (err))
1946 err = getsrv_libdns (name, list, &srvcount);
1949 #endif /*USE_LIBDNS*/
1950 err = getsrv_standard (name, list, &srvcount);
1954 if (gpg_err_code (err) == GPG_ERR_NO_NAME)
1959 /* Now we have an array of all the srv records. */
1961 /* Order by priority */
1962 qsort(*list,srvcount,sizeof(struct srventry),priosort);
1964 /* For each priority, move the zero-weighted items first. */
1965 for (i=0; i < srvcount; i++)
1969 for (j=i;j < srvcount && (*list)[i].priority == (*list)[j].priority; j++)
1971 if((*list)[j].weight==0)
1976 struct srventry temp;
1978 memcpy (&temp,&(*list)[j],sizeof(struct srventry));
1979 memcpy (&(*list)[j],&(*list)[i],sizeof(struct srventry));
1980 memcpy (&(*list)[i],&temp,sizeof(struct srventry));
1988 /* Run the RFC-2782 weighting algorithm. We don't need very high
1989 quality randomness for this, so regular libc srand/rand is
1997 srand (time (NULL)*getpid());
2001 for (i=0; i < srvcount; i++)
2004 float prio_count=0,chose;
2006 for (j=i; j < srvcount && (*list)[i].priority == (*list)[j].priority; j++)
2008 prio_count+=(*list)[j].weight;
2009 (*list)[j].run_count=prio_count;
2012 chose=prio_count*rand()/RAND_MAX;
2014 for (j=i;j<srvcount && (*list)[i].priority==(*list)[j].priority;j++)
2016 if (chose<=(*list)[j].run_count)
2021 struct srventry temp;
2023 memcpy(&temp,&(*list)[j],sizeof(struct srventry));
2024 memcpy(&(*list)[j],&(*list)[i],sizeof(struct srventry));
2025 memcpy(&(*list)[i],&temp,sizeof(struct srventry));
2036 log_debug ("dns: getsrv(%s): %s\n", name, gpg_strerror (err));
2038 log_debug ("dns: getsrv(%s) -> %u records\n", name, srvcount);
2041 *r_count = srvcount;
2049 /* libdns version of get_dns_cname. */
2051 get_dns_cname_libdns (const char *name, char **r_cname)
2054 struct dns_resolver *res;
2055 struct dns_packet *ans = NULL;
2056 struct dns_cname cname;
2059 err = libdns_res_open (&res);
2063 err = libdns_res_submit (res, name, DNS_T_CNAME, DNS_C_IN);
2067 err = libdns_res_wait (res);
2071 ans = dns_res_fetch (res, &derr);
2074 err = libdns_error_to_gpg_error (derr);
2078 /* Check the rcode. */
2079 switch (dns_p_rcode (ans))
2081 case DNS_RC_NOERROR: break;
2082 case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
2083 default: err = GPG_ERR_SERVER_FAILED; break;
2088 /* Parse the result into CNAME. */
2089 err = libdns_error_to_gpg_error (dns_p_study (ans));
2093 if (!dns_d_cname (&cname, sizeof cname, name, strlen (name), ans, &derr))
2095 err = libdns_error_to_gpg_error (derr);
2100 *r_cname = xtrystrdup (cname.host);
2102 err = gpg_error_from_syserror ();
2105 /* Libdns appends the root zone part which is problematic
2106 * for most other functions - strip it. */
2107 if (**r_cname && (*r_cname)[strlen (*r_cname)-1] == '.')
2108 (*r_cname)[strlen (*r_cname)-1] = 0;
2113 dns_res_close (res);
2116 #endif /*USE_LIBDNS*/
2119 /* Standard resolver version of get_dns_cname. */
2121 get_dns_cname_standard (const char *name, char **r_cname)
2123 #ifdef HAVE_SYSTEM_RESOLVER
2127 unsigned char ans[2048];
2130 unsigned char *answer = res.ans;
2131 HEADER *header = res.header;
2132 unsigned char *pt, *emsg;
2135 int cnamesize = 1025;
2138 /* Do not allow a query using the standard resolver in Tor mode. */
2143 r = res_query (name, C_IN, T_CERT, answer, sizeof res.ans);
2146 return get_h_errno_as_gpg_error ();
2147 if (r < sizeof (HEADER))
2148 return gpg_error (GPG_ERR_SERVER_FAILED);
2149 if (r > sizeof res.ans)
2150 return gpg_error (GPG_ERR_SYSTEM_BUG);
2151 if (header->rcode != NOERROR || !(count=ntohs (header->ancount)))
2152 return gpg_error (GPG_ERR_NO_NAME); /* Error or no record found. */
2154 return gpg_error (GPG_ERR_SERVER_FAILED);
2157 pt = &answer[sizeof(HEADER)];
2158 rc = dn_skipname (pt, emsg);
2160 return gpg_error (GPG_ERR_SERVER_FAILED);
2162 pt += rc + QFIXEDSZ;
2164 return gpg_error (GPG_ERR_SERVER_FAILED);
2166 rc = dn_skipname (pt, emsg);
2168 return gpg_error (GPG_ERR_SERVER_FAILED);
2169 pt += rc + 2 + 2 + 4;
2171 return gpg_error (GPG_ERR_SERVER_FAILED);
2172 pt += 2; /* Skip rdlen */
2174 cname = xtrymalloc (cnamesize);
2176 return gpg_error_from_syserror ();
2178 rc = dn_expand (answer, emsg, pt, cname, cnamesize -1);
2182 return gpg_error (GPG_ERR_SERVER_FAILED);
2184 *r_cname = xtryrealloc (cname, strlen (cname)+1);
2187 err = gpg_error_from_syserror ();
2193 #else /*!HAVE_SYSTEM_RESOLVER*/
2197 return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
2199 #endif /*!HAVE_SYSTEM_RESOLVER*/
2204 get_dns_cname (const char *name, char **r_cname)
2211 if (!standard_resolver)
2213 err = get_dns_cname_libdns (name, r_cname);
2214 if (err && libdns_switch_port_p (err))
2215 err = get_dns_cname_libdns (name, r_cname);
2218 #endif /*USE_LIBDNS*/
2220 err = get_dns_cname_standard (name, r_cname);
2222 log_debug ("get_dns_cname(%s)%s%s\n", name,
2223 err ? ": " : " -> ",
2224 err ? gpg_strerror (err) : *r_cname);