1 /* vi: set sw=4 ts=4: */
3 * Mini nslookup implementation for busybox
6 * Copyright (C) 2000 by Lineo, inc.
7 * Written by John Beppu <beppu@lineo.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
32 #include <sys/socket.h>
33 #include <sys/types.h>
34 #include <netinet/in.h>
37 | I'm only implementing non-interactive mode;
38 | I totally forgot nslookup even had an interactive mode.
41 | + find out how to use non-default name servers
42 | + find out how the real nslookup gets the default name server
45 static const char nslookup_usage[] = "nslookup [HOST]\n\n";
48 /* I have to see how the real nslookup does this.
49 * I could dig through /etc/resolv.conf, but is there a
50 * better (programatic) way?
52 static void server_fprint(FILE * dst)
54 fprintf(dst, "Server: %s\n", "something");
55 fprintf(dst, "Address: %s\n\n", "something");
58 /* only works for IPv4 */
59 static int addr_fprint(char *addr, FILE * dst)
63 uint32_t *x = (uint32_t *) addr;
66 split[0] = (ip & 0xff000000) >> 24;
67 split[1] = (ip & 0x00ff0000) >> 16;
68 split[2] = (ip & 0x0000ff00) >> 8;
69 split[3] = (ip & 0x000000ff);
70 fprintf(dst, "%d.%d.%d.%d", split[0], split[1], split[2], split[3]
75 /* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+
78 static uint32_t str_to_addr(const char *addr)
83 sscanf(addr, "%d.%d.%d.%d",
84 &split[0], &split[1], &split[2], &split[3]);
86 /* assuming sscanf worked */
87 ip = (split[0] << 24) |
88 (split[1] << 16) | (split[2] << 8) | (split[3]);
93 /* takes the NULL-terminated array h_addr_list, and
94 * prints its contents appropriately
96 static int addr_list_fprint(char **h_addr_list, FILE * dst)
99 char *addr_string = (h_addr_list[1])
100 ? "Addresses" : "Address";
102 fprintf(dst, "%s: ", addr_string);
103 for (i = 0, j = 0; h_addr_list[i]; i++, j++) {
104 addr_fprint(h_addr_list[i], dst);
106 /* real nslookup does this */
108 if (h_addr_list[i + 1]) {
113 if (h_addr_list[i + 1]) {
123 /* gethostbyaddr wrapper */
124 static struct hostent *gethostbyaddr_wrapper(const char *address)
128 addr.s_addr = str_to_addr(address);
129 return gethostbyaddr((char *) &addr, 4, AF_INET); /* IPv4 only for now */
132 /* print the results as nslookup would */
133 static struct hostent *hostent_fprint(struct hostent *host, FILE * dst)
136 fprintf(dst, "Name: %s\n", host->h_name);
137 addr_list_fprint(host->h_addr_list, dst);
139 fprintf(dst, "*** %s\n", hstrerror(h_errno));
145 /* naive function to check whether char *s is an ip address */
146 static int is_ip_address(const char *s)
149 if ((isdigit(*s)) || (*s == '.')) {
158 /* ________________________________________________________________________ */
159 int nslookup_main(int argc, char **argv)
161 struct hostent *host;
164 usage(nslookup_usage);
167 server_fprint(stdout);
168 if (is_ip_address(argv[1])) {
169 host = gethostbyaddr_wrapper(argv[1]);
171 host = gethostbyname(argv[1]);
173 hostent_fprint(host, stdout);
177 /* $Id: nslookup.c,v 1.4 2000/02/08 19:58:47 erik Exp $ */