nslookup: full circle. Here we started IPv6 work. Use "new API"

and thus save a few bytes.


git-svn-id: svn://busybox.net/trunk/busybox@17477 69ca8d6d-28ef-0310-b511-8ec308f3f277

1 files changed, 88 insertions, 29 deletions

diff --git a/networking/nslookup.c b/networking/nslookup.c
index 5a08844f0..af0816215 100644
--- a/networking/nslookup.c
+++ b/networking/nslookup.c
@@ -47,7 +47,7 @@
  * ns3.kernel.org  internet address = 204.152.191.36
  */
 
-static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
+/*static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
 {
         if (buflen <= 0) return -1;
         buf[0] = '\0';
@@ -61,9 +61,11 @@ static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
         }
         return -1;
 }
+*/
 
 static int print_host(const char *hostname, const char *header)
 {
+#if 0
         char str[128];  /* IPv6 address will fit, hostnames hopefully too */
         struct addrinfo *result = NULL;
         int rc;
@@ -76,6 +78,7 @@ static int print_host(const char *hostname, const char *header)
         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); ?
@@ -93,6 +96,75 @@ static int print_host(const char *hostname, const char *header)
         }
         freeaddrinfo(result);
         return (rc != 0);
+
+#else
+        /* We can't use host2sockaddr() - we want to get ALL addresses,
+         * not just one */
+
+        struct addrinfo *result = NULL;
+        int rc;
+        struct addrinfo hint;
+
+        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;
+                unsigned cnt = 0;
+
+                printf("%-10s %s\n", header, hostname);
+                // printf("%s\n", cur->ai_canonname); ?
+                while (cur) {
+                        char *dotted, *revhost;
+                        dotted = xmalloc_sockaddr2dotted_noport(cur->ai_addr, cur->ai_addrlen);
+                        revhost = xmalloc_sockaddr2hostonly_noport(cur->ai_addr, cur->ai_addrlen);
+
+                        printf("Address %u: %s%c", ++cnt, dotted, revhost ? ' ' : '\n');
+                        if (revhost) {
+                                puts(revhost);
+                                if (ENABLE_FEATURE_CLEAN_UP)
+                                        free(revhost);
+                        }
+                        if (ENABLE_FEATURE_CLEAN_UP)
+                                free(dotted);
+                        cur = cur->ai_next;
+                }
+        } else {
+#if ENABLE_VERBOSE_RESOLUTION_ERRORS
+                bb_error_msg("getaddrinfo('%s') failed: %s", hostname, gai_strerror(rc));
+#else
+                bb_error_msg("can't resolve '%s'", hostname);
+#endif
+        }
+        if (ENABLE_FEATURE_CLEAN_UP)
+                freeaddrinfo(result);
+        return (rc != 0);
+#endif
+}
+
+
+/* lookup the default nameserver and display it */
+static void server_print(void)
+{
+        char *server;
+
+        server = xmalloc_sockaddr2dotted_noport((struct sockaddr*)&_res.nsaddr_list[0],
+                        sizeof(struct sockaddr_in));
+        /* 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. */
+        print_host(server, "Server:");
+        if (ENABLE_FEATURE_CLEAN_UP)
+                free(server);
+        puts("");
 }
 
 
@@ -109,40 +181,27 @@ static void set_default_dns(char *server)
 }
 
 
-/* lookup the default nameserver and display it */
-static void server_print(void)
-{
-        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)
 {
-        /*
-        * 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
-        */
+        /* 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)
+
+        /* initialize DNS structure _res used in printing the default
+         * name server and in the explicit name server option feature. */
+        res_init();
+        /* rfc2133 says this enables IPv6 lookups */
+        /* (but it also says "may be enabled in /etc/resolv.conf|) */
+        /*_res.options |= RES_USE_INET6;*/
+
+        if(argc == 3)
                 set_default_dns(argv[2]);
 
         server_print();
-        return print_host(argv[1], "Name:  ");
+        return print_host(argv[1], "Name:");
 }
-