/*
* Mini nslookup implementation for busybox
*
- * Copyright (C) 2000 by Lineo, inc.
- * Written by John Beppu <beppu@lineo.com>
+ * Copyright (C) 1999,2000 by Lineo, inc. and John Beppu
+ * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * 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"
-#include <ctype.h>
-#include <errno.h>
-#include <stdio.h>
-#include <string.h>
-
-#include <netdb.h>
-#include <sys/socket.h>
-#include <sys/types.h>
-#include <netinet/in.h>
/*
- | I'm only implementing non-interactive mode;
- | I totally forgot nslookup even had an interactive mode.
- |
- | [ TODO ]
- | + find out how to use non-default name servers
- | + find out how the real nslookup gets the default name server
+ * I'm only implementing non-interactive mode;
+ * I totally forgot nslookup even had an interactive mode.
*/
-/* I have to see how the real nslookup does this.
- * I could dig through /etc/resolv.conf, but is there a
- * better (programatic) way?
+/* 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 void server_fprint(FILE * dst)
-{
- fprintf(dst, "Server: %s\n", "default");
- fprintf(dst, "Address: %s\n\n", "default");
-}
-
-/* only works for IPv4 */
-static int addr_fprint(char *addr, FILE * dst)
-{
- u_int8_t split[4];
- u_int32_t ip;
- u_int32_t *x = (u_int32_t *) addr;
-
- ip = ntohl(*x);
- split[0] = (ip & 0xff000000) >> 24;
- split[1] = (ip & 0x00ff0000) >> 16;
- split[2] = (ip & 0x0000ff00) >> 8;
- split[3] = (ip & 0x000000ff);
- fprintf(dst, "%d.%d.%d.%d", split[0], split[1], split[2], split[3]
- );
- return 0;
-}
-/* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+
- * into a u_int32_t
- */
-static u_int32_t str_to_addr(const char *addr)
+static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
{
- u_int32_t split[4];
- u_int32_t ip;
-
- sscanf(addr, "%d.%d.%d.%d",
- &split[0], &split[1], &split[2], &split[3]);
-
- /* assuming sscanf worked */
- ip = (split[0] << 24) |
- (split[1] << 16) | (split[2] << 8) | (split[3]);
-
- return htonl(ip);
+ 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;
}
-/* takes the NULL-terminated array h_addr_list, and
- * prints its contents appropriately
- */
-static int addr_list_fprint(char **h_addr_list, FILE * dst)
+static int print_host(const char *hostname, const char *header)
{
- int i, j;
- char *addr_string = (h_addr_list[1])
- ? "Addresses: " : "Address: ";
-
- fprintf(dst, "%s ", addr_string);
- for (i = 0, j = 0; h_addr_list[i]; i++, j++) {
- addr_fprint(h_addr_list[i], dst);
-
- /* real nslookup does this */
- if (j == 4) {
- if (h_addr_list[i + 1]) {
- fprintf(dst, "\n ");
- }
- j = 0;
- } else {
- if (h_addr_list[i + 1]) {
- fprintf(dst, ", ");
- }
+ 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);
+ if (getnameinfo(cur->ai_addr, cur->ai_addrlen, str, sizeof(str), NULL, 0, NI_NAMEREQD))
+ str[0] = '\0';
+ printf(" %s\n", str);
+ cur = cur->ai_next;
}
-
+ } else {
+ bb_error_msg("getaddrinfo('%s') failed: %s", hostname, gai_strerror(rc));
}
- fprintf(dst, "\n");
- return 0;
+ freeaddrinfo(result);
+ return (rc != 0);
}
-/* gethostbyaddr wrapper */
-static struct hostent *gethostbyaddr_wrapper(const char *address)
-{
- struct in_addr addr;
-
- addr.s_addr = str_to_addr(address);
- return gethostbyaddr((char *) &addr, 4, AF_INET); /* IPv4 only for now */
-}
-/* print the results as nslookup would */
-static struct hostent *hostent_fprint(struct hostent *host, FILE * dst)
+/* 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)
{
- if (host) {
- fprintf(dst, "Name: %s\n", host->h_name);
- addr_list_fprint(host->h_addr_list, dst);
- } else {
- fprintf(dst, "*** Unknown host\n");
+ 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;
}
- return host;
}
-/* naive function to check whether char *s is an ip address */
-static int is_ip_address(const char *s)
+/* lookup the default nameserver and display it */
+static void server_print(void)
{
- while (*s) {
- if ((isdigit(*s)) || (*s == '.')) {
- s++;
- continue;
- }
- return 0;
- }
- return 1;
+ 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)
{
- struct hostent *host;
-
- if (argc < 2 || *argv[1]=='-') {
- usage(nslookup_usage);
- }
-
- server_fprint(stdout);
- if (is_ip_address(argv[1])) {
- host = gethostbyaddr_wrapper(argv[1]);
- } else {
- host = gethostbyname(argv[1]);
- }
- hostent_fprint(host, stdout);
- return EXIT_SUCCESS;
+ /*
+ * 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 1.13 2000/12/01 02:55:13 kraai Exp $ */
+/* $Id: nslookup.c,v 1.33 2004/10/13 07:25:01 andersen Exp $ */
projects / oweals / busybox.git / blobdiff