1 files changed, 206 insertions, 0 deletions

diff --git a/busybox/networking/nslookup.c b/busybox/networking/nslookup.c
new file mode 100644
index 000000000..936fa33cb
--- /dev/null
+++ b/busybox/networking/nslookup.c
@@ -0,0 +1,206 @@
+/* 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
+ *
+ * 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
+ *
+ */
+
+#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.
+ */
+
+/* only works for IPv4 */
+static int addr_fprint(char *addr)
+{
+        uint8_t split[4];
+        uint32_t ip;
+        uint32_t *x = (uint32_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
+ */
+static int addr_list_fprint(char **h_addr_list)
+{
+        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(", ");
+                        }
+                }
+
+        }
+        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");
+        }
+        return host;
+}
+
+/* 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:");
+        printf("\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)
+{
+        struct in_addr server_in_addr;
+
+        if(inet_aton(server,&server_in_addr))
+        {
+                _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)
+{
+        while (*s) {
+                if ((isdigit(*s)) || (*s == '.')) {
+                        s++;
+                        continue;
+                }
+                return 0;
+        }
+        return 1;
+}
+
+/* ________________________________________________________________________ */
+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.
+        */
+
+        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();
+        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;
+}
+
+/* $Id: nslookup.c,v 1.33 2004/10/13 07:25:01 andersen Exp $ */