busybox/networking/nslookup.c

/* vi: set sw=4 ts=4: */
/*
 * Mini nslookup implementation for busybox
 *
 * Copyright (C) 1999,2000 by Lineo, inc. and John Beppu
 * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
 *
 * Correct default name server display and explicit name server option
 * added by Ben Zeckel <bzeckel@hmc.edu> June 2001
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include <resolv.h>
#include "busybox.h"

/*
 *  I'm only implementing non-interactive mode;
 *  I totally forgot nslookup even had an interactive mode.
 */

/* Examples of 'standard' nslookup output
 * $ nslookup yahoo.com
 * Server:         128.193.0.10
 * Address:        128.193.0.10#53
 *
 * Non-authoritative answer:
 * Name:   yahoo.com
 * Address: 216.109.112.135
 * Name:   yahoo.com
 * Address: 66.94.234.13
 *
 * $ nslookup 204.152.191.37
 * Server:         128.193.4.20
 * Address:        128.193.4.20#53
 *
 * Non-authoritative answer:
 * 37.191.152.204.in-addr.arpa     canonical name = 37.32-27.191.152.204.in-addr.arpa.
 * 37.32-27.191.152.204.in-addr.arpa       name = zeus-pub2.kernel.org.
 *
 * Authoritative answers can be found from:
 * 32-27.191.152.204.in-addr.arpa  nameserver = ns1.kernel.org.
 * 32-27.191.152.204.in-addr.arpa  nameserver = ns2.kernel.org.
 * 32-27.191.152.204.in-addr.arpa  nameserver = ns3.kernel.org.
 * ns1.kernel.org  internet address = 140.211.167.34
 * ns2.kernel.org  internet address = 204.152.191.4
 * ns3.kernel.org  internet address = 204.152.191.36
 */

static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
{
	if (buflen <= 0) return -1;
	buf[0] = '\0';
	if (saddr->sa_family == AF_INET) {
		inet_ntop(AF_INET, &((struct sockaddr_in*)saddr)->sin_addr, buf, buflen);
		return 0;
	}
	if (saddr->sa_family == AF_INET6) {
		inet_ntop(AF_INET6, &((struct sockaddr_in6*)saddr)->sin6_addr, buf, buflen);
		return 0;
	}
	return -1;
}

static int print_host(const char *hostname, const char *header)
{
	char str[128];	/* IPv6 address will fit, hostnames hopefully too */
	struct addrinfo *result = NULL;
	int rc;
	struct addrinfo hint;

	memset(&hint, 0 , sizeof(hint));
	/* hint.ai_family = AF_UNSPEC; - zero anyway */
	/* Needed. Or else we will get each address thrice (or more)
	 * for each possible socket type (tcp,udp,raw...): */
	hint.ai_socktype = SOCK_STREAM;
	// hint.ai_flags = AI_CANONNAME;
	rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);
	if (!rc) {
		struct addrinfo *cur = result;
		// printf("%s\n", cur->ai_canonname); ?
		while (cur) {
			sockaddr_to_dotted(cur->ai_addr, str, sizeof(str));
			printf("%s  %s\nAddress: %s", header, hostname, str);
			str[0] = ' ';
			if (getnameinfo(cur->ai_addr, cur->ai_addrlen, str+1, sizeof(str)-1, NULL, 0, NI_NAMEREQD))
				str[0] = '\0';
			puts(str);
			cur = cur->ai_next;
		}
	} else {
		bb_error_msg("getaddrinfo('%s') failed: %s", hostname, gai_strerror(rc));
	}
	freeaddrinfo(result);
	return (rc != 0);
}


/* alter the global _res nameserver structure to use
   an explicit dns server instead of what is in /etc/resolv.h */
static void set_default_dns(char *server)
{
	struct in_addr server_in_addr;

	if (inet_pton(AF_INET, server, &server_in_addr) > 0) {
		_res.nscount = 1;
		_res.nsaddr_list[0].sin_addr = server_in_addr;
	}
}


/* lookup the default nameserver and display it */
static void server_print(void)
{
	char str[INET6_ADDRSTRLEN];

	sockaddr_to_dotted((struct sockaddr*)&_res.nsaddr_list[0], str, sizeof(str));
	print_host(str, "Server:");
	puts("");
}


int nslookup_main(int argc, char **argv)
{
	/*
	* initialize DNS structure _res used in printing the default
	* name server and in the explicit name server option feature.
	*/

	res_init();

	/*
	* We allow 1 or 2 arguments.
	* The first is the name to be looked up and the second is an
	* optional DNS server with which to do the lookup.
	* More than 3 arguments is an error to follow the pattern of the
	* standard nslookup
	*/

	if (argc < 2 || *argv[1] == '-' || argc > 3)
		bb_show_usage();
	else if(argc == 3)
		set_default_dns(argv[2]);

	server_print();
	return print_host(argv[1], "Name:  ");
}

/* $Id: nslookup.c,v 1.1 2007-09-01 22:43:53 niro Exp $ */
1	niro	532	/* 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 $ */