Diff of /tags/mkinitrd-6_1_11/busybox/networking/nslookup.c

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	revision 532 by niro, Sat Sep 1 22:45:15 2007 UTC	revision 816 by niro, Fri Apr 24 18:33:46 2009 UTC
#	Line 12	Line 12
12	*/	*/
13
14	#include <resolv.h>	#include <resolv.h>
15	#include "busybox.h"	#include "libbb.h"
16
17	/*	/*
18	*  I'm only implementing non-interactive mode;	* I'm only implementing non-interactive mode;
19	*  I totally forgot nslookup even had an interactive mode.	* I totally forgot nslookup even had an interactive mode.
20		*
21		* This applet is the only user of res_init(). Without it,
22		* you may avoid pulling in _res global from libc.
23	*/	*/
24
25	/* Examples of 'standard' nslookup output	/* Examples of 'standard' nslookup output
#	Line 47	Line 50
50	* ns3.kernel.org  internet address = 204.152.191.36	* ns3.kernel.org  internet address = 204.152.191.36
51	*/	*/
52
	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;
	}
53	static int print_host(const char *hostname, const char *header)	static int print_host(const char *hostname, const char *header)
54	{	{
55	char str[128]; /* IPv6 address will fit, hostnames hopefully too */	/* We can't use xhost2sockaddr() - we want to get ALL addresses,
56		* not just one */
57	struct addrinfo *result = NULL;	struct addrinfo *result = NULL;
58	int rc;	int rc;
59	struct addrinfo hint;	struct addrinfo hint;
#	Line 76  static int print_host(const char *hostna	Line 65  static int print_host(const char *hostna
65	hint.ai_socktype = SOCK_STREAM;	hint.ai_socktype = SOCK_STREAM;
66	// hint.ai_flags = AI_CANONNAME;	// hint.ai_flags = AI_CANONNAME;
67	rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);	rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);
68
69	if (!rc) {	if (!rc) {
70	struct addrinfo *cur = result;	struct addrinfo *cur = result;
71	// printf("%s\n", cur->ai_canonname); ?	unsigned cnt = 0;
72
73		printf("%-10s %s\n", header, hostname);
74		// puts(cur->ai_canonname); ?
75	while (cur) {	while (cur) {
76	sockaddr_to_dotted(cur->ai_addr, str, sizeof(str));	char *dotted, *revhost;
77	printf("%s  %s\nAddress: %s", header, hostname, str);	dotted = xmalloc_sockaddr2dotted_noport(cur->ai_addr);
78	str[0] = ' ';	revhost = xmalloc_sockaddr2hostonly_noport(cur->ai_addr);
79	if (getnameinfo(cur->ai_addr, cur->ai_addrlen, str+1, sizeof(str)-1, NULL, 0, NI_NAMEREQD))
80	str[0] = '\0';	printf("Address %u: %s%c", ++cnt, dotted, revhost ? ' ' : '\n');
81	puts(str);	if (revhost) {
82		puts(revhost);
83		if (ENABLE_FEATURE_CLEAN_UP)
84		free(revhost);
85		}
86		if (ENABLE_FEATURE_CLEAN_UP)
87		free(dotted);
88	cur = cur->ai_next;	cur = cur->ai_next;
89	}	}
90	} else {	} else {
91	bb_error_msg("getaddrinfo('%s') failed: %s", hostname, gai_strerror(rc));	#if ENABLE_VERBOSE_RESOLUTION_ERRORS
92		bb_error_msg("can't resolve '%s': %s", hostname, gai_strerror(rc));
93		#else
94		bb_error_msg("can't resolve '%s'", hostname);
95		#endif
96	}	}
97	freeaddrinfo(result);	if (ENABLE_FEATURE_CLEAN_UP)
98		freeaddrinfo(result);
99	return (rc != 0);	return (rc != 0);
100	}	}
101
102		/* lookup the default nameserver and display it */
103		static void server_print(void)
104		{
105		char *server;
106
107		server = xmalloc_sockaddr2dotted_noport((struct sockaddr*)&_res.nsaddr_list[0]);
108		/* I honestly don't know what to do if DNS server has _IPv6 address_.
109		* Probably it is listed in
110		* _res._u._ext_.nsaddrs[MAXNS] (of type "struct sockaddr_in6*" each)
111		* but how to find out whether resolver uses
112		* _res.nsaddr_list[] or _res._u._ext_.nsaddrs[], or both?
113		* Looks like classic design from hell, BIND-grade. Hard to surpass. */
114		print_host(server, "Server:");
115		if (ENABLE_FEATURE_CLEAN_UP)
116		free(server);
117		bb_putchar('\n');
118		}
119
120	/* alter the global _res nameserver structure to use	/* alter the global _res nameserver structure to use
121	an explicit dns server instead of what is in /etc/resolv.h */	an explicit dns server instead of what is in /etc/resolv.conf */
122	static void set_default_dns(char *server)	static void set_default_dns(char *server)
123	{	{
124	struct in_addr server_in_addr;	struct in_addr server_in_addr;
#	Line 108  static void set_default_dns(char *server	Line 129  static void set_default_dns(char *server
129	}	}
130	}	}
131
132		int nslookup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	/* 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("");
	}
133	int nslookup_main(int argc, char **argv)	int nslookup_main(int argc, char **argv)
134	{	{
135	/*	/* We allow 1 or 2 arguments.
136	* initialize DNS structure _res used in printing the default	* The first is the name to be looked up and the second is an
137	* name server and in the explicit name server option feature.	* optional DNS server with which to do the lookup.
138	*/	* More than 3 arguments is an error to follow the pattern of the
139		* standard nslookup */
140		if (!argv[1] || argv[1][0] == '-' || argc > 3)
141		bb_show_usage();
142
143		/* initialize DNS structure _res used in printing the default
144		* name server and in the explicit name server option feature. */
145	res_init();	res_init();
146		/* rfc2133 says this enables IPv6 lookups */
147		/* (but it also says "may be enabled in /etc/resolv.conf") */
148		/*_res.options |= RES_USE_INET6;*/
149
150	/*	if (argv[2])
	* 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)
151	set_default_dns(argv[2]);	set_default_dns(argv[2]);
152
153	server_print();	server_print();
154	return print_host(argv[1], "Name:  ");	return print_host(argv[1], "Name:");
155	}	}
	/* $Id: nslookup.c,v 1.1 2007-09-01 22:43:53 niro Exp $ */

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