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    Contents of /trunk/mkinitrd-magellan/busybox/networking/nslookup.c

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    Revision 532 - (show annotations) (download)
    Sat Sep 1 22:45:15 2007 UTC (16 years, 8 months ago) by niro
    File MIME type: text/plain
    File size: 4200 byte(s) 
    -import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
    1 /* vi: set sw=4 ts=4: */
    2 /*
    3 * Mini nslookup implementation for busybox
    4 *
    5 * Copyright (C) 1999,2000 by Lineo, inc. and John Beppu
    6 * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
    7 *
    8 * Correct default name server display and explicit name server option
    9 * added by Ben Zeckel <bzeckel@hmc.edu> June 2001
    10 *
    11 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
    12 */
    13
    14 #include <resolv.h>
    15 #include "busybox.h"
    16
    17 /*
    18 * I'm only implementing non-interactive mode;
    19 * I totally forgot nslookup even had an interactive mode.
    20 */
    21
    22 /* Examples of 'standard' nslookup output
    23 * $ nslookup yahoo.com
    24 * Server: 128.193.0.10
    25 * Address: 128.193.0.10#53
    26 *
    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
    36 *
    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.
    40 *
    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 */
    49
    50 static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
    51 {
    52 if (buflen <= 0) return -1;
    53 buf[0] = '\0';
    54 if (saddr->sa_family == AF_INET) {
    55 inet_ntop(AF_INET, &((struct sockaddr_in*)saddr)->sin_addr, buf, buflen);
    56 return 0;
    57 }
    58 if (saddr->sa_family == AF_INET6) {
    59 inet_ntop(AF_INET6, &((struct sockaddr_in6*)saddr)->sin6_addr, buf, buflen);
    60 return 0;
    61 }
    62 return -1;
    63 }
    64
    65 static int print_host(const char *hostname, const char *header)
    66 {
    67 char str[128]; /* IPv6 address will fit, hostnames hopefully too */
    68 struct addrinfo *result = NULL;
    69 int rc;
    70 struct addrinfo hint;
    71
    72 memset(&hint, 0 , sizeof(hint));
    73 /* hint.ai_family = AF_UNSPEC; - zero anyway */
    74 /* Needed. Or else we will get each address thrice (or more)
    75 * for each possible socket type (tcp,udp,raw...): */
    76 hint.ai_socktype = SOCK_STREAM;
    77 // hint.ai_flags = AI_CANONNAME;
    78 rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);
    79 if (!rc) {
    80 struct addrinfo *cur = result;
    81 // printf("%s\n", cur->ai_canonname); ?
    82 while (cur) {
    83 sockaddr_to_dotted(cur->ai_addr, str, sizeof(str));
    84 printf("%s %s\nAddress: %s", header, hostname, str);
    85 str[0] = ' ';
    86 if (getnameinfo(cur->ai_addr, cur->ai_addrlen, str+1, sizeof(str)-1, NULL, 0, NI_NAMEREQD))
    87 str[0] = '\0';
    88 puts(str);
    89 cur = cur->ai_next;
    90 }
    91 } else {
    92 bb_error_msg("getaddrinfo('%s') failed: %s", hostname, gai_strerror(rc));
    93 }
    94 freeaddrinfo(result);
    95 return (rc != 0);
    96 }
    97
    98
    99 /* alter the global _res nameserver structure to use
    100 an explicit dns server instead of what is in /etc/resolv.h */
    101 static void set_default_dns(char *server)
    102 {
    103 struct in_addr server_in_addr;
    104
    105 if (inet_pton(AF_INET, server, &server_in_addr) > 0) {
    106 _res.nscount = 1;
    107 _res.nsaddr_list[0].sin_addr = server_in_addr;
    108 }
    109 }
    110
    111
    112 /* lookup the default nameserver and display it */
    113 static void server_print(void)
    114 {
    115 char str[INET6_ADDRSTRLEN];
    116
    117 sockaddr_to_dotted((struct sockaddr*)&_res.nsaddr_list[0], str, sizeof(str));
    118 print_host(str, "Server:");
    119 puts("");
    120 }
    121
    122
    123 int nslookup_main(int argc, char **argv)
    124 {
    125 /*
    126 * initialize DNS structure _res used in printing the default
    127 * name server and in the explicit name server option feature.
    128 */
    129
    130 res_init();
    131
    132 /*
    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
    138 */
    139
    140 if (argc < 2 || *argv[1] == '-' || argc > 3)
    141 bb_show_usage();
    142 else if(argc == 3)
    143 set_default_dns(argv[2]);
    144
    145 server_print();
    146 return print_host(argv[1], "Name: ");
    147 }
    148
    149 /* $Id: nslookup.c,v 1.1 2007-09-01 22:43:53 niro Exp $ */