diff options
Diffstat (limited to 'release/src/router/busybox/networking/nslookup.c')
| -rw-r--r-- | release/src/router/busybox/networking/nslookup.c | 287 |
1 files changed, 130 insertions, 157 deletions
diff --git a/release/src/router/busybox/networking/nslookup.c b/release/src/router/busybox/networking/nslookup.c index 307f6104..26287114 100644 --- a/release/src/router/busybox/networking/nslookup.c +++ b/release/src/router/busybox/networking/nslookup.c @@ -5,198 +5,171 @@ * 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 + * Correct default name server display and explicit name server option * added by Ben Zeckel <bzeckel@hmc.edu> June 2001 * - * 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 - * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */ -#include <ctype.h> -#include <errno.h> -#include <stdio.h> -#include <string.h> -#include <stdlib.h> - -#include <netdb.h> -#include <sys/socket.h> -#include <sys/types.h> -#include <netinet/in.h> #include <resolv.h> -#include <arpa/inet.h> -#include "busybox.h" +#include "libbb.h" /* - | I'm only implementing non-interactive mode; - | I totally forgot nslookup even had an interactive mode. + * I'm only implementing non-interactive mode; + * I totally forgot nslookup even had an interactive mode. + * + * This applet is the only user of res_init(). Without it, + * you may avoid pulling in _res global from libc. */ -/* only works for IPv4 */ -static int addr_fprint(char *addr) -{ - 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); - printf("%d.%d.%d.%d", split[0], split[1], split[2], split[3]); - return 0; -} - -/* takes the NULL-terminated array h_addr_list, and - * prints its contents appropriately +/* 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 addr_list_fprint(char **h_addr_list) + +static int print_host(const char *hostname, const char *header) { - int i, j; - char *addr_string = (h_addr_list[1]) - ? "Addresses: " : "Address: "; - - printf("%s ", addr_string); - for (i = 0, j = 0; h_addr_list[i]; i++, j++) { - addr_fprint(h_addr_list[i]); - - /* real nslookup does this */ - if (j == 4) { - if (h_addr_list[i + 1]) { - printf("\n "); - } - j = 0; - } else { - if (h_addr_list[i + 1]) { - printf(", "); + /* We can't use xhost2sockaddr() - we want to get ALL addresses, + * not just one */ + 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; + unsigned cnt = 0; + + printf("%-10s %s\n", header, hostname); + // puts(cur->ai_canonname); ? + while (cur) { + char *dotted, *revhost; + dotted = xmalloc_sockaddr2dotted_noport(cur->ai_addr); + revhost = xmalloc_sockaddr2hostonly_noport(cur->ai_addr); + + printf("Address %u: %s%c", ++cnt, dotted, revhost ? ' ' : '\n'); + if (revhost) { + puts(revhost); + if (ENABLE_FEATURE_CLEAN_UP) + free(revhost); } + if (ENABLE_FEATURE_CLEAN_UP) + free(dotted); + cur = cur->ai_next; } - - } - printf("\n"); - return 0; -} - -/* print the results as nslookup would */ -static struct hostent *hostent_fprint(struct hostent *host, const char *server_host) -{ - if (host) { - printf("%s %s\n", server_host, host->h_name); - addr_list_fprint(host->h_addr_list); } else { - printf("*** Unknown host\n"); +#if ENABLE_VERBOSE_RESOLUTION_ERRORS + bb_error_msg("can't resolve '%s': %s", hostname, gai_strerror(rc)); +#else + bb_error_msg("can't resolve '%s'", hostname); +#endif } - return host; -} - -/* 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) -{ - 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); -} - -/* 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 */ + if (ENABLE_FEATURE_CLEAN_UP) + freeaddrinfo(result); + return (rc != 0); } /* lookup the default nameserver and display it */ -static inline void server_print(void) +static void server_print(void) { - struct sockaddr_in def = _res.nsaddr_list[0]; - char *ip = inet_ntoa(def.sin_addr); - - hostent_fprint(gethostbyaddr_wrapper(ip), "Server:"); - printf("\n"); + char *server; + struct sockaddr *sa; + +#if ENABLE_FEATURE_IPV6 + sa = (struct sockaddr*)_res._u._ext.nsaddrs[0]; + if (!sa) +#endif + sa = (struct sockaddr*)&_res.nsaddr_list[0]; + server = xmalloc_sockaddr2dotted_noport(sa); + + print_host(server, "Server:"); + if (ENABLE_FEATURE_CLEAN_UP) + free(server); + bb_putchar('\n'); } /* alter the global _res nameserver structure to use - an explicit dns server instead of what is in /etc/resolv.h */ -static inline void set_default_dns(char *server) + an explicit dns server instead of what is in /etc/resolv.conf */ +static void set_default_dns(const char *server) { - struct in_addr server_in_addr; + len_and_sockaddr *lsa; - if(inet_aton(server,&server_in_addr)) - { + /* NB: this works even with, say, "[::1]:5353"! :) */ + lsa = xhost2sockaddr(server, 53); + + if (lsa->u.sa.sa_family == AF_INET) { _res.nscount = 1; - _res.nsaddr_list[0].sin_addr = server_in_addr; + /* struct copy */ + _res.nsaddr_list[0] = lsa->u.sin; } -} - -/* naive function to check whether char *s is an ip address */ -static int is_ip_address(const char *s) -{ - while (*s) { - if ((isdigit(*s)) || (*s == '.')) { - s++; - continue; - } - return 0; +#if ENABLE_FEATURE_IPV6 + /* Hoped libc can cope with IPv4 address there too. + * No such luck, glibc 2.4 segfaults even with IPv6, + * maybe I misunderstand how to make glibc use IPv6 addr? + * (uclibc 0.9.31+ should work) */ + if (lsa->u.sa.sa_family == AF_INET6) { + // glibc neither SEGVs nor sends any dgrams with this + // (strace shows no socket ops): + //_res.nscount = 0; + _res._u._ext.nscount = 1; + /* store a pointer to part of malloc'ed lsa */ + _res._u._ext.nsaddrs[0] = &lsa->u.sin6; + /* must not free(lsa)! */ } - return 1; +#endif } -/* ________________________________________________________________________ */ +int nslookup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int nslookup_main(int argc, char **argv) { - struct hostent *host; + /* 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 (!argv[1] || argv[1][0] == '-' || argc > 3) + bb_show_usage(); - /* - * initialize DNS structure _res used in printing the default - * name server and in the explicit name server option feature. - */ - + /* initialize DNS structure _res used in printing the default + * name server and in the explicit name server option feature. */ res_init(); + /* rfc2133 says this enables IPv6 lookups */ + /* (but it also says "may be enabled in /etc/resolv.conf") */ + /*_res.options |= RES_USE_INET6;*/ - /* - * 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) + if (argv[2]) set_default_dns(argv[2]); server_print(); - if (is_ip_address(argv[1])) { - host = gethostbyaddr_wrapper(argv[1]); - } else { - host = xgethostbyname(argv[1]); - } - hostent_fprint(host, "Name: "); - return EXIT_SUCCESS; + return print_host(argv[1], "Name:"); } - -/* $Id: nslookup.c,v 1.1.3.1 2004/12/29 07:07:46 honor Exp $ */ |