[IPV4] ipconfig: Implement DHCP Class-identifier

From : Rainer Jochem <rainer.jochem@mpi-sb.mpg.de>

Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ipconfig.c

@@ -140,6 +140,8 @@ __be32 ic_servaddr = NONE;	/* Boot server IP address */
 __be32 root_server_addr = NONE;	/* Address of NFS server */
 u8 root_server_path[256] = { 0, };	/* Path to mount as root */
 
+static char vendor_class_identifier[253]; /* vendor class identifier */
+
 /* Persistent data: */
 
 static int ic_proto_used;			/* Protocol used, if any */
@@ -588,6 +590,7 @@ ic_dhcp_init_options(u8 *options)
 	u8 mt = ((ic_servaddr == NONE)
 		 ? DHCPDISCOVER : DHCPREQUEST);
 	u8 *e = options;
+	int len;
 
 #ifdef IPCONFIG_DEBUG
 	printk("DHCP: Sending message type %d\n", mt);
@@ -628,6 +631,16 @@ ic_dhcp_init_options(u8 *options)
 		*e++ = sizeof(ic_req_params);
 		memcpy(e, ic_req_params, sizeof(ic_req_params));
 		e += sizeof(ic_req_params);
+
+		if (*vendor_class_identifier) {
+			printk(KERN_INFO "DHCP: sending class identifier \"%s\"\n",
+			       vendor_class_identifier);
+			*e++ = 60;	/* Class-identifier */
+			len = strlen(vendor_class_identifier);
+			*e++ = len;
+			memcpy(e, vendor_class_identifier, len);
+			e += len;
+		}
 	}
 
 	*e++ = 255;	/* End of the list */
@@ -1513,5 +1526,16 @@ static int __init nfsaddrs_config_setup(char *addrs)
 	return ip_auto_config_setup(addrs);
 }
 
+static int __init vendor_class_identifier_setup(char *addrs)
+{
+	if (strlcpy(vendor_class_identifier, addrs,
+		    sizeof(vendor_class_identifier))
+	    >= sizeof(vendor_class_identifier))
+		printk(KERN_WARNING "DHCP: vendorclass too long, truncated to \"%s\"",
+		       vendor_class_identifier);
+	return 1;
+}
+
 __setup("ip=", ip_auto_config_setup);
 __setup("nfsaddrs=", nfsaddrs_config_setup);
+__setup("dhcpclass=", vendor_class_identifier_setup);