Add DNS support
On 04 Oct 2008 Pieter posted a dns implementation for U-Boot.
http://www.mail-archive.com/u-boot-users@lists.sourceforge.net/msg10216.html
>
> DNS can be enabled by setting CFG_CMD_DNS. After performing a query,
> the serverip environment var is updated.
>
> Probably there are some cosmetic issues with the patch. Unfortunatly I
> do not have the time to correct these. So if anybody else likes DNS
> support in U-Boot and has the time, feel free to patch it in the main tree.
Here it is again - slightly modified & smaller:
- update to 2009-06 (Pieter's patch was for U-Boot 1.2.0)
- README.dns is added
- syntax is changed (now takes a third option, the env var to store
the result in)
- add a random port() function in net.c
- sort Makefile in ./net/Makefile
- dns just returns unless a env var is given
- run through checkpatch, and clean up style issues
- remove packet from stack
- cleaned up some comments
- failure returns much faster (if server responds, don't wait for
timeout)
- use built in functions (memcpy) rather than byte copy.
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Pieter Voorthuijsen <pieter.voorthuijsen@prodrive.nl>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
diff --git a/common/cmd_net.c b/common/cmd_net.c
index 68183c4..ac706ae 100644
--- a/common/cmd_net.c
+++ b/common/cmd_net.c
@@ -353,3 +353,52 @@
"[NTP server IP]\n"
);
#endif
+
+#if defined(CONFIG_CMD_DNS)
+int do_dns(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+ if (argc == 1) {
+ cmd_usage(cmdtp);
+ return -1;
+ }
+
+ /*
+ * We should check for a valid hostname:
+ * - Each label must be between 1 and 63 characters long
+ * - the entire hostname has a maximum of 255 characters
+ * - only the ASCII letters 'a' through 'z' (case-insensitive),
+ * the digits '0' through '9', and the hyphen
+ * - cannot begin or end with a hyphen
+ * - no other symbols, punctuation characters, or blank spaces are
+ * permitted
+ * but hey - this is a minimalist implmentation, so only check length
+ * and let the name server deal with things.
+ */
+ if (strlen(argv[1]) >= 255) {
+ printf("dns error: hostname too long\n");
+ return 1;
+ }
+
+ NetDNSResolve = argv[1];
+
+ if (argc == 3)
+ NetDNSenvvar = argv[2];
+ else
+ NetDNSenvvar = NULL;
+
+ if (NetLoop(DNS) < 0) {
+ printf("dns lookup of %s failed, check setup\n", argv[1]);
+ return 1;
+ }
+
+ return 0;
+}
+
+U_BOOT_CMD(
+ dns, 3, 1, do_dns,
+ "lookup the IP of a hostname",
+ "hostname [envvar]"
+);
+
+#endif /* CONFIG_CMD_DNS */
+
