Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 2 | /* |
| 3 | * Mini nslookup implementation for busybox |
| 4 | * |
Eric Andersen | bdfd0d7 | 2001-10-24 05:00:29 +0000 | [diff] [blame] | 5 | * Copyright (C) 1999,2000 by Lineo, inc. and John Beppu |
| 6 | * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org> |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 7 | * |
Eric Andersen | 39cdf4e | 2004-01-30 22:40:05 +0000 | [diff] [blame] | 8 | * Correct default name server display and explicit name server option |
Robert Griebl | 31a2e20 | 2002-07-24 00:56:56 +0000 | [diff] [blame] | 9 | * added by Ben Zeckel <bzeckel@hmc.edu> June 2001 |
| 10 | * |
"Robert P. J. Day" | 2819f75 | 2006-07-11 11:32:31 +0000 | [diff] [blame] | 11 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 12 | */ |
| 13 | |
Eric Andersen | dab3d46 | 2001-06-12 22:21:24 +0000 | [diff] [blame] | 14 | #include <resolv.h> |
Denis Vlasenko | b6adbf1 | 2007-05-26 19:00:18 +0000 | [diff] [blame] | 15 | #include "libbb.h" |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 16 | |
John Beppu | 50bc101 | 2000-01-30 09:47:16 +0000 | [diff] [blame] | 17 | /* |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 18 | * I'm only implementing non-interactive mode; |
| 19 | * I totally forgot nslookup even had an interactive mode. |
John Beppu | 50bc101 | 2000-01-30 09:47:16 +0000 | [diff] [blame] | 20 | */ |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 21 | |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 22 | /* Examples of 'standard' nslookup output |
| 23 | * $ nslookup yahoo.com |
| 24 | * Server: 128.193.0.10 |
| 25 | * Address: 128.193.0.10#53 |
Denis Vlasenko | f7996f3 | 2007-01-11 17:20:00 +0000 | [diff] [blame] | 26 | * |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 27 | * 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 Vlasenko | f7996f3 | 2007-01-11 17:20:00 +0000 | [diff] [blame] | 36 | * |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 37 | * 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 Vlasenko | f7996f3 | 2007-01-11 17:20:00 +0000 | [diff] [blame] | 40 | * |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 41 | * 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 Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 49 | |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 50 | static int print_host(const char *hostname, const char *header) |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 51 | { |
Denis Vlasenko | 42823d5 | 2007-02-04 02:39:08 +0000 | [diff] [blame] | 52 | /* We can't use xhost2sockaddr() - we want to get ALL addresses, |
Denis Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 53 | * 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 Vlasenko | a27a11b | 2007-08-18 14:16:39 +0000 | [diff] [blame] | 75 | dotted = xmalloc_sockaddr2dotted_noport(cur->ai_addr); |
| 76 | revhost = xmalloc_sockaddr2hostonly_noport(cur->ai_addr); |
Denis Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 77 | |
| 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 Vlasenko | 5de9e9c | 2007-01-22 22:46:04 +0000 | [diff] [blame] | 90 | bb_error_msg("can't resolve '%s': %s", hostname, gai_strerror(rc)); |
Denis Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 91 | #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 Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 98 | } |
| 99 | |
Denis Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 100 | /* lookup the default nameserver and display it */ |
| 101 | static void server_print(void) |
| 102 | { |
| 103 | char *server; |
| 104 | |
Denis Vlasenko | a27a11b | 2007-08-18 14:16:39 +0000 | [diff] [blame] | 105 | server = xmalloc_sockaddr2dotted_noport((struct sockaddr*)&_res.nsaddr_list[0]); |
Denis Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 106 | /* 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 Vlasenko | 4daad90 | 2007-09-27 10:20:47 +0000 | [diff] [blame^] | 115 | bb_putchar('\n'); |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 116 | } |
| 117 | |
Robert Griebl | 31a2e20 | 2002-07-24 00:56:56 +0000 | [diff] [blame] | 118 | /* alter the global _res nameserver structure to use |
| 119 | an explicit dns server instead of what is in /etc/resolv.h */ |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 120 | static void set_default_dns(char *server) |
Robert Griebl | 31a2e20 | 2002-07-24 00:56:56 +0000 | [diff] [blame] | 121 | { |
| 122 | struct in_addr server_in_addr; |
| 123 | |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 124 | if (inet_pton(AF_INET, server, &server_in_addr) > 0) { |
Robert Griebl | 31a2e20 | 2002-07-24 00:56:56 +0000 | [diff] [blame] | 125 | _res.nscount = 1; |
| 126 | _res.nsaddr_list[0].sin_addr = server_in_addr; |
| 127 | } |
Eric Andersen | 39cdf4e | 2004-01-30 22:40:05 +0000 | [diff] [blame] | 128 | } |
Robert Griebl | 31a2e20 | 2002-07-24 00:56:56 +0000 | [diff] [blame] | 129 | |
Denis Vlasenko | 06af216 | 2007-02-03 17:28:39 +0000 | [diff] [blame] | 130 | int nslookup_main(int argc, char **argv); |
Erik Andersen | e49d5ec | 2000-02-08 19:58:47 +0000 | [diff] [blame] | 131 | int nslookup_main(int argc, char **argv) |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 132 | { |
Denis Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 133 | /* 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 Griebl | 31a2e20 | 2002-07-24 00:56:56 +0000 | [diff] [blame] | 138 | |
Denis Vlasenko | ebe578a | 2006-10-26 17:17:59 +0000 | [diff] [blame] | 139 | if (argc < 2 || *argv[1] == '-' || argc > 3) |
Manuel Novoa III | cad5364 | 2003-03-19 09:13:01 +0000 | [diff] [blame] | 140 | bb_show_usage(); |
Denis Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 141 | |
| 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 Vlasenko | 51742f4 | 2007-04-12 00:32:05 +0000 | [diff] [blame] | 149 | if (argc == 3) |
Robert Griebl | 31a2e20 | 2002-07-24 00:56:56 +0000 | [diff] [blame] | 150 | set_default_dns(argv[2]); |
| 151 | |
Eric Andersen | fe9888a | 2001-01-20 21:51:21 +0000 | [diff] [blame] | 152 | server_print(); |
Denis Vlasenko | 448f024 | 2007-01-22 22:43:05 +0000 | [diff] [blame] | 153 | return print_host(argv[1], "Name:"); |
John Beppu | b332e77 | 2000-01-29 12:59:01 +0000 | [diff] [blame] | 154 | } |