nslookup: allow usage of IPv6 addresses or hostnames
for DNS server name; allow for port specification.
Tested to work: "nslookup google.com [::1]:5353"
diff --git a/networking/nslookup.c b/networking/nslookup.c
index 73ccb0d..8a820ce 100644
--- a/networking/nslookup.c
+++ b/networking/nslookup.c
@@ -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;