svn commit: trunk/busybox/networking

[vda at busybox.net]

Author: vda
Date: 2008-11-16 11:02:26 -0800 (Sun, 16 Nov 2008)
New Revision: 24063

Log:
nslookup: allow usage of IPv6 addresses or hostnames
 for DNS server name; allow for port specification.
 Tested to work: "nslookup google.com [::1]:5353"



Modified:
   trunk/busybox/networking/nslookup.c


Changeset:
Modified: trunk/busybox/networking/nslookup.c
===================================================================
--- trunk/busybox/networking/nslookup.c	2008-11-16 19:00:21 UTC (rev 24062)
+++ trunk/busybox/networking/nslookup.c	2008-11-16 19:02:26 UTC (rev 24063)
@@ -103,14 +103,15 @@
 static void server_print(void)
 {
 	char *server;
+	struct sockaddr *sa;
 
-	server = xmalloc_sockaddr2dotted_noport((struct sockaddr*)&_res.nsaddr_list[0]);
-	/* I honestly don't know what to do if DNS server has _IPv6 address_.
-	 * Probably it is listed in
-	 * _res._u._ext_.nsaddrs[MAXNS] (of type "struct sockaddr_in6*" each)
-	 * but how to find out whether resolver uses
-	 * _res.nsaddr_list[] or _res._u._ext_.nsaddrs[], or both?
-	 * Looks like classic design from hell, BIND-grade. Hard to surpass. */
+#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);
@@ -119,14 +120,28 @@
 
 /* alter the global _res nameserver structure to use
    an explicit dns server instead of what is in /etc/resolv.conf */
-static void set_default_dns(char *server)
+static void set_default_dns(const char *server)
 {
-	struct in_addr server_in_addr;
+	len_and_sockaddr *lsa;
 
-	if (inet_pton(AF_INET, server, &server_in_addr) > 0) {
+	/* 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;
 	}
+#if ENABLE_FEATURE_IPV6
+// Hoping libc will handle an IPv4 address there too,
+// if it so happens that family is indeed AF_INET
+//	if (lsa->u.sa.sa_family == AF_INET6) {
+		_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)! */
+//	}
+#endif
 }
 
 int nslookup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;