blob: e5bb56f81cad99bb68e3bb6020d82e5660cc82f4 [file] [log] [blame]
Erik Andersene49d5ec2000-02-08 19:58:47 +00001/* vi: set sw=4 ts=4: */
John Beppub332e772000-01-29 12:59:01 +00002/*
3 * Mini nslookup implementation for busybox
4 *
Eric Andersenbdfd0d72001-10-24 05:00:29 +00005 * Copyright (C) 1999,2000 by Lineo, inc. and John Beppu
6 * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
John Beppub332e772000-01-29 12:59:01 +00007 *
Eric Andersen39cdf4e2004-01-30 22:40:05 +00008 * Correct default name server display and explicit name server option
Robert Griebl31a2e202002-07-24 00:56:56 +00009 * added by Ben Zeckel <bzeckel@hmc.edu> June 2001
10 *
"Robert P. J. Day"2819f752006-07-11 11:32:31 +000011 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
John Beppub332e772000-01-29 12:59:01 +000012 */
13
Eric Andersendab3d462001-06-12 22:21:24 +000014#include <resolv.h>
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000015#include "libbb.h"
John Beppub332e772000-01-29 12:59:01 +000016
John Beppu50bc1012000-01-30 09:47:16 +000017/*
Denis Vlasenkoebe578a2006-10-26 17:17:59 +000018 * I'm only implementing non-interactive mode;
19 * I totally forgot nslookup even had an interactive mode.
John Beppu50bc1012000-01-30 09:47:16 +000020 */
John Beppub332e772000-01-29 12:59:01 +000021
Denis Vlasenkoebe578a2006-10-26 17:17:59 +000022/* Examples of 'standard' nslookup output
23 * $ nslookup yahoo.com
24 * Server: 128.193.0.10
25 * Address: 128.193.0.10#53
Denis Vlasenkof7996f32007-01-11 17:20:00 +000026 *
Denis Vlasenkoebe578a2006-10-26 17:17:59 +000027 * Non-authoritative answer:
28 * Name: yahoo.com
29 * Address: 216.109.112.135
30 * Name: yahoo.com
31 * Address: 66.94.234.13
32 *
33 * $ nslookup 204.152.191.37
34 * Server: 128.193.4.20
35 * Address: 128.193.4.20#53
Denis Vlasenkof7996f32007-01-11 17:20:00 +000036 *
Denis Vlasenkoebe578a2006-10-26 17:17:59 +000037 * Non-authoritative answer:
38 * 37.191.152.204.in-addr.arpa canonical name = 37.32-27.191.152.204.in-addr.arpa.
39 * 37.32-27.191.152.204.in-addr.arpa name = zeus-pub2.kernel.org.
Denis Vlasenkof7996f32007-01-11 17:20:00 +000040 *
Denis Vlasenkoebe578a2006-10-26 17:17:59 +000041 * Authoritative answers can be found from:
42 * 32-27.191.152.204.in-addr.arpa nameserver = ns1.kernel.org.
43 * 32-27.191.152.204.in-addr.arpa nameserver = ns2.kernel.org.
44 * 32-27.191.152.204.in-addr.arpa nameserver = ns3.kernel.org.
45 * ns1.kernel.org internet address = 140.211.167.34
46 * ns2.kernel.org internet address = 204.152.191.4
47 * ns3.kernel.org internet address = 204.152.191.36
48 */
John Beppub332e772000-01-29 12:59:01 +000049
Denis Vlasenkoebe578a2006-10-26 17:17:59 +000050static int print_host(const char *hostname, const char *header)
John Beppub332e772000-01-29 12:59:01 +000051{
Denis Vlasenko42823d52007-02-04 02:39:08 +000052 /* We can't use xhost2sockaddr() - we want to get ALL addresses,
Denis Vlasenko448f0242007-01-22 22:43:05 +000053 * not just one */
54
55 struct addrinfo *result = NULL;
56 int rc;
57 struct addrinfo hint;
58
59 memset(&hint, 0 , sizeof(hint));
60 /* hint.ai_family = AF_UNSPEC; - zero anyway */
61 /* Needed. Or else we will get each address thrice (or more)
62 * for each possible socket type (tcp,udp,raw...): */
63 hint.ai_socktype = SOCK_STREAM;
64 // hint.ai_flags = AI_CANONNAME;
65 rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);
66
67 if (!rc) {
68 struct addrinfo *cur = result;
69 unsigned cnt = 0;
70
71 printf("%-10s %s\n", header, hostname);
72 // printf("%s\n", cur->ai_canonname); ?
73 while (cur) {
74 char *dotted, *revhost;
Denis Vlasenkoa27a11b2007-08-18 14:16:39 +000075 dotted = xmalloc_sockaddr2dotted_noport(cur->ai_addr);
76 revhost = xmalloc_sockaddr2hostonly_noport(cur->ai_addr);
Denis Vlasenko448f0242007-01-22 22:43:05 +000077
78 printf("Address %u: %s%c", ++cnt, dotted, revhost ? ' ' : '\n');
79 if (revhost) {
80 puts(revhost);
81 if (ENABLE_FEATURE_CLEAN_UP)
82 free(revhost);
83 }
84 if (ENABLE_FEATURE_CLEAN_UP)
85 free(dotted);
86 cur = cur->ai_next;
87 }
88 } else {
89#if ENABLE_VERBOSE_RESOLUTION_ERRORS
Denis Vlasenko5de9e9c2007-01-22 22:46:04 +000090 bb_error_msg("can't resolve '%s': %s", hostname, gai_strerror(rc));
Denis Vlasenko448f0242007-01-22 22:43:05 +000091#else
92 bb_error_msg("can't resolve '%s'", hostname);
93#endif
94 }
95 if (ENABLE_FEATURE_CLEAN_UP)
96 freeaddrinfo(result);
97 return (rc != 0);
Denis Vlasenko448f0242007-01-22 22:43:05 +000098}
99
Denis Vlasenko448f0242007-01-22 22:43:05 +0000100/* lookup the default nameserver and display it */
101static void server_print(void)
102{
103 char *server;
104
Denis Vlasenkoa27a11b2007-08-18 14:16:39 +0000105 server = xmalloc_sockaddr2dotted_noport((struct sockaddr*)&_res.nsaddr_list[0]);
Denis Vlasenko448f0242007-01-22 22:43:05 +0000106 /* I honestly don't know what to do if DNS server has _IPv6 address_.
107 * Probably it is listed in
108 * _res._u._ext_.nsaddrs[MAXNS] (of type "struct sockaddr_in6*" each)
109 * but how to find out whether resolver uses
110 * _res.nsaddr_list[] or _res._u._ext_.nsaddrs[], or both?
111 * Looks like classic design from hell, BIND-grade. Hard to surpass. */
112 print_host(server, "Server:");
113 if (ENABLE_FEATURE_CLEAN_UP)
114 free(server);
Denis Vlasenko4daad902007-09-27 10:20:47 +0000115 bb_putchar('\n');
John Beppub332e772000-01-29 12:59:01 +0000116}
117
Robert Griebl31a2e202002-07-24 00:56:56 +0000118/* alter the global _res nameserver structure to use
119 an explicit dns server instead of what is in /etc/resolv.h */
Denis Vlasenkoebe578a2006-10-26 17:17:59 +0000120static void set_default_dns(char *server)
Robert Griebl31a2e202002-07-24 00:56:56 +0000121{
122 struct in_addr server_in_addr;
123
Denis Vlasenkoebe578a2006-10-26 17:17:59 +0000124 if (inet_pton(AF_INET, server, &server_in_addr) > 0) {
Robert Griebl31a2e202002-07-24 00:56:56 +0000125 _res.nscount = 1;
126 _res.nsaddr_list[0].sin_addr = server_in_addr;
127 }
Eric Andersen39cdf4e2004-01-30 22:40:05 +0000128}
Robert Griebl31a2e202002-07-24 00:56:56 +0000129
Denis Vlasenko06af2162007-02-03 17:28:39 +0000130int nslookup_main(int argc, char **argv);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000131int nslookup_main(int argc, char **argv)
John Beppub332e772000-01-29 12:59:01 +0000132{
Denis Vlasenko448f0242007-01-22 22:43:05 +0000133 /* We allow 1 or 2 arguments.
134 * The first is the name to be looked up and the second is an
135 * optional DNS server with which to do the lookup.
136 * More than 3 arguments is an error to follow the pattern of the
137 * standard nslookup */
Robert Griebl31a2e202002-07-24 00:56:56 +0000138
Denis Vlasenkoebe578a2006-10-26 17:17:59 +0000139 if (argc < 2 || *argv[1] == '-' || argc > 3)
Manuel Novoa III cad53642003-03-19 09:13:01 +0000140 bb_show_usage();
Denis Vlasenko448f0242007-01-22 22:43:05 +0000141
142 /* initialize DNS structure _res used in printing the default
143 * name server and in the explicit name server option feature. */
144 res_init();
145 /* rfc2133 says this enables IPv6 lookups */
146 /* (but it also says "may be enabled in /etc/resolv.conf|) */
147 /*_res.options |= RES_USE_INET6;*/
148
Denis Vlasenko51742f42007-04-12 00:32:05 +0000149 if (argc == 3)
Robert Griebl31a2e202002-07-24 00:56:56 +0000150 set_default_dns(argv[2]);
151
Eric Andersenfe9888a2001-01-20 21:51:21 +0000152 server_print();
Denis Vlasenko448f0242007-01-22 22:43:05 +0000153 return print_host(argv[1], "Name:");
John Beppub332e772000-01-29 12:59:01 +0000154}