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nslookup: make it more IPv6 friendly

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This commit is contained in:
Denis Vlasenko 2006-10-26 17:17:59 +00:00
parent 68f2187265
commit ebe578ab2f
2 changed files with 81 additions and 126 deletions
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205
networking/nslookup.c
View File

@ -11,152 +11,116 @@
* 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 <stdint.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"
/*
| 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.
*/
/* only works for IPv4 */
static int addr_fprint(char *addr)
{
uint8_t split[4];
uint32_t ip;
uint32_t *x = (uint32_t *) addr;
/* 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
*/
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;
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;
}
/* takes the NULL-terminated array h_addr_list, and
* prints its contents appropriately
*/
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: ";
char str[128]; /* IPv6 address will fit, hostnames hopefully too */
struct addrinfo *result = NULL;
int rc;
struct addrinfo hint;
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(", ");
}
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;
}
}
puts("");
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");
bb_error_msg("getaddrinfo('%s') failed: %s", hostname, gai_strerror(rc));
}
return host;
freeaddrinfo(result);
return (rc != 0);
}
/* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+
* into a uint32_t
*/
static uint32_t str_to_addr(const char *addr)
{
uint32_t split[4];
uint32_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 */
}
/* lookup the default nameserver and display it */
static inline 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:");
puts("");
}
/* 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)
static void set_default_dns(char *server)
{
struct in_addr server_in_addr;
if(inet_aton(server,&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;
}
}
/* 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;
/*
* initialize DNS structure _res used in printing the default
* name server and in the explicit name server option feature.
@ -172,22 +136,13 @@ int nslookup_main(int argc, char **argv)
* standard nslookup
*/
if (argc < 2 || *argv[1]=='-' || argc > 3)
if (argc < 2 || *argv[1] == '-' || argc > 3)
bb_show_usage();
else if(argc == 3)
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: ");
if (host) {
return EXIT_SUCCESS;
}
return EXIT_FAILURE;
return print_host(argv[1], "Name: ");
}
/* $Id: nslookup.c,v 1.33 2004/10/13 07:25:01 andersen Exp $ */

2
networking/ping6.c
View File

@ -329,7 +329,7 @@ static void ping(const char *host)
pingaddr.sin6_family = AF_INET6;
hostent = xgethostbyname2(host, AF_INET6);
if (hostent->h_addrtype != AF_INET6)
bb_error_msg_and_die("unknown address type; only AF_INET6 is currently supported.");
bb_error_msg_and_die("unknown address type; only AF_INET6 is currently supported");
memcpy(&pingaddr.sin6_addr, hostent->h_addr, sizeof(pingaddr.sin6_addr));