Save server's MAC address in environment

Linux's netconsole works much better when you can pass it the MAC address of
the server. (otherwise it just uses broadcast, which everyone else on my
network complains about :)

This sets the env var "serveraddr" (to match ethaddr), so that you can pass
it to linux with whatever bootargs you want to....

addnetconsole=set bootargs $(bootargs) netconsole=@$(ipaddr)/eth0,@$(serverip)/$(serveraddr)

Signed-of-by: Robin Getz <rgetz@blackfin.uclinux.org>

Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

README

@@ -1184,6 +1184,11 @@ The following options need to be configured:
 		Defines a default value for the IP address of a TFTP
 		server to contact when using the "tftboot" command.
 
+		CONFIG_KEEP_SERVERADDR
+
+		Keeps the server's MAC address, in the env 'serveraddr'
+		for passing to bootargs (like Linux's netconsole option)
+
 - Multicast TFTP Mode:
 		CONFIG_MCAST_TFTP
 

net/net.c

@@ -1287,6 +1287,15 @@ NetReceive(volatile uchar * inpkt, int len)
 			/* are we waiting for a reply */
 			if (!NetArpWaitPacketIP || !NetArpWaitPacketMAC)
 				break;
+
+#ifdef CONFIG_KEEP_SERVERADDR
+			if (NetServerIP == NetArpWaitPacketIP) {
+				char buf[20];
+				sprintf(buf, "%pM", arp->ar_data);
+				setenv("serveraddr", buf);
+			}
+#endif
+
 #ifdef ET_DEBUG
 			printf("Got ARP REPLY, set server/gtwy eth addr (%pM)\n",
 				arp->ar_data);