nslookup -- a work in progress...

1 files changed, 168 insertions, 0 deletions

diff --git a/nslookup.c b/nslookup.c
new file mode 100644
index 0000000..0a2a574
--- /dev/null
+++ b/nslookup.c
@@ -0,0 +1,168 @@
+/*
+ * Mini nslookup implementation for busybox
+ *
+ *
+ * Copyright (C) 2000 by Lineo, inc.
+ * Written by John Beppu <beppu@lineo.com>
+ *
+ * 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 "internal.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>
+
+
+static const char nslookup_usage[] =
+"only implementing non-interactive mode\n"
+"I totally forgot nslookup even had an interactive mode\n"
+;
+
+
+/* */
+static void
+server_fprint(FILE *dst)
+{
+    fprintf(dst, "Server:  %s\n", "something");
+    fprintf(dst, "Address:  %s\n\n", "something");
+}
+
+/* only works for IPv4 */
+static int
+addr_fprint(char *addr, FILE *dst)
+{
+    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);
+    fprintf (
+	dst, "%d.%d.%d.%d", 
+	split[0], split[1], split[2], split[3]
+    );
+    return 0;
+}
+
+/* */
+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);
+}
+
+/* */
+static int
+addr_list_fprint(char **h_addr_list, FILE *dst)
+{
+    int	    i;
+    char    *addr_string = (h_addr_list[1]) 
+	? "Addresses" 
+	: "Address";
+
+    fprintf(dst, "%s:  ", addr_string);
+    for (i = 0; h_addr_list[i]; i++) {
+	addr_fprint(h_addr_list[i], dst);
+	if (h_addr_list[i+1]) {
+	    fprintf(dst, ", ");
+	}
+    }
+    fprintf(dst,"\n");
+    return 0;
+}
+
+/* */
+static struct hostent *
+lookup_by_name(const char *hostname)
+{
+    struct hostent  *host;
+
+    host = gethostbyname(hostname);
+    if (host) {
+	fprintf(stdout, "Name:    %s\n", host->h_name);
+	addr_list_fprint(host->h_addr_list, stdout);
+    } else {
+	herror("crap");
+    }
+    return host;
+}
+
+/* */
+static struct hostent *
+lookup_by_addr(const char *addr)
+{
+    struct hostent  *host;
+
+    host = gethostbyaddr(addr, 4, AF_INET); /* IPv4 only for now */
+    if (host) {
+	fprintf(stdout, "Name:    %s\n", host->h_name);
+	addr_list_fprint(host->h_addr_list, stdout);
+    } else {
+	herror("crap");
+    }
+    return host;
+}
+
+/* */
+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 in_addr addr;
+
+    server_fprint(stdout);
+    if (is_ip_address(argv[1])) {
+	addr.s_addr = str_to_addr(argv[1]);
+	lookup_by_addr((char *) &addr); 
+    } else {
+	lookup_by_name(argv[1]);
+    }
+    return 0;
+}
+
+/* $Id: nslookup.c,v 1.1 2000/01/29 12:59:01 beppu Exp $ */