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/doc/README.dns b/doc/README.dns
new file mode 100644
index 0000000..deeccd7
--- /dev/null
+++ b/doc/README.dns
@@ -0,0 +1,64 @@
+Domain Name System
+-------------------------------------------
+
+The Domain Name System (DNS) is a hierarchical naming system for computers,
+services, or any resource participating in the Internet. It associates various
+information with domain names assigned to each of the participants. Most
+importantly, it translates domain names meaningful to humans into the numerical
+(binary) identifiers associated with networking equipment for the purpose of
+locating and addressing these devices world-wide. An often used analogy to
+explain the Domain Name System is that it serves as the "phone book" for the
+Internet by translating human-friendly computer hostnames into IP addresses.
+For example, www.example.com translates to 208.77.188.166.
+
+For more information on DNS - http://en.wikipedia.org/wiki/Domain_Name_System
+
+
+
+U-Boot and DNS
+------------------------------------------
+
+CONFIG_CMD_DNS - controls if the 'dns' command is compiled in. If it is, it
+ will send name lookups to the dns server (env var 'dnsip')
+ Turning this option on will about abou 1k to U-Boot's size.
+
+ Example:
+
+bfin> print dnsip
+dnsip=192.168.0.1
+
+bfin> dns www.google.com
+66.102.1.104
+
+ By default, dns does nothing except print the IP number on
+ the default console - which by itself, would be pretty
+ useless. Adding a third argument to the dns command will
+ use that as the environment variable to be set.
+
+ Example:
+
+bfin> print googleip
+## Error: "googleip" not defined
+bfin> dns www.google.com googleip
+64.233.161.104
+bfin> print googleip
+googleip=64.233.161.104
+bfin> ping ${googleip}
+Using Blackfin EMAC device
+host 64.233.161.104 is alive
+
+ In this way, you can lookup, and set many more meaningful
+ things.
+
+bfin> sntp
+ntpserverip not set
+bfin> dns pool.ntp.org ntpserverip
+72.18.205.156
+bfin> sntp
+Date: 2009-07-18 Time: 4:06:57
+
+ For some helpful things that can be related to DNS in U-Boot,
+ look at the top level README for these config options:
+ CONFIG_CMD_DHCP
+ CONFIG_BOOTP_DNS
+ CONFIG_BOOTP_DNS2
