4 files changed, 62 insertions, 1 deletions
diff --git a/networking/udhcp/Config.in b/networking/udhcp/Config.in
index 5baaa6a49..674470a39 100644
--- a/networking/udhcp/Config.in
+++ b/networking/udhcp/Config.in
@@ -38,5 +38,14 @@ config CONFIG_FEATURE_UDHCP_DEBUG
 	help
 	  Please submit a patch to add help text for this item.
 
+config CONFIG_FEATURE_UDHCPC_IP
+	bool "  Compile udhcpc with ip support"
+	default n
+	depends on CONFIG_UDHCPC
+	help
+	  Say yes if you are using the ip command instead of route and ifconfig
+	  in your scripts to bring up the interface.
+	  This is needed as ip wants the subnet as a bitprefix not an ip value.
+
 endmenu
 
diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c
index 58144728e..3f3a38963 100644
--- a/networking/udhcp/options.c
+++ b/networking/udhcp/options.c
@@ -13,11 +13,16 @@
 #include "options.h"
 #include "leases.h"
 
+#include "config.h"
 
 /* supported options are easily added here */
 struct dhcp_option options[] = {
 	/* name[10]	flags					code */
-	{"subnet",	OPTION_IP | OPTION_REQ,			0x01},
+#ifdef CONFIG_FEATURE_UDHCPC_IP
+	{"subnet",	OPTION_IP | OPTION_REQ | OPTION_PREFIX,	0x01},
+#else
+ 	{"subnet",	OPTION_IP | OPTION_REQ,			0x01},
+#endif
 	{"timezone",	OPTION_S32,				0x02},
 	{"router",	OPTION_IP | OPTION_LIST | OPTION_REQ,	0x03},
 	{"timesvr",	OPTION_IP | OPTION_LIST,		0x04},
diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h
index 1fded2ef4..dccaa2af9 100644
--- a/networking/udhcp/options.h
+++ b/networking/udhcp/options.h
@@ -4,6 +4,8 @@
 
 #include "packet.h"
 
+#include "config.h"
+
 #define TYPE_MASK	0x0F
 
 enum {
@@ -20,6 +22,7 @@ enum {
 
 #define OPTION_REQ	0x10 /* have the client request this option */
 #define OPTION_LIST	0x20 /* There can be a list of 1 or more of these */
+#define OPTION_PREFIX	0x40 /* ip wants a prefix instead of a ip for subnet */
 
 struct dhcp_option {
 	char name[10];
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
index 4ce23aafc..1c6f1bd33 100644
--- a/networking/udhcp/script.c
+++ b/networking/udhcp/script.c
@@ -37,6 +37,8 @@
 #include "options.h"
 #include "debug.h"
 
+#include "config.h"
+
 /* get a rough idea of how long an option will be (rounding up...) */
 static int max_option_length[] = {
 	[OPTION_IP] =		sizeof("255.255.255.255 "),
@@ -62,6 +64,37 @@ static int sprintip(char *dest, char *pre, unsigned char *ip) {
 	return sprintf(dest, "%s%d.%d.%d.%d ", pre, ip[0], ip[1], ip[2], ip[3]);
 }
 
+#ifdef CONFIG_FEATURE_UDHCPC_IP
+/* convert a netmask (255.255.255.0) into the length (24) */
+static int inet_ntom (const char *src, short *dst)
+{
+	in_addr_t mask, num;
+
+	mask = ntohl(*(unsigned int *)src);
+
+	for (num = mask; num & 1; num >>= 1);
+
+	if (num != 0 && mask != 0)
+	{
+		for (num = ~mask; num & 1; num >>= 1);
+		if (num)
+			return 0;
+	}
+
+	for (num = 0; mask; mask <<= 1)
+		num++;
+
+	*dst = num;
+
+	return 1;
+}
+
+static int sprintprefix(char *dest, char *pre, unsigned char *ip) {
+	short sdest = 0;
+	inet_ntom(ip, &sdest);
+	return sprintf(dest, "%s%hd ", pre, sdest);
+}
+#endif
 
 /* Fill dest with the text of option 'option'. */
 static void fill_options(char *dest, unsigned char *option, struct dhcp_option *type_p)
@@ -84,9 +117,20 @@ static void fill_options(char *dest, unsigned char *option, struct dhcp_option *
 			*(dest++) = '/';
 			option += 4;
 			optlen = 4;
+#ifndef CONFIG_FEATURE_UDHCPC_IP
 		case OPTION_IP:	/* Works regardless of host byte order. */
+#endif
 			dest += sprintip(dest, "", option);
  			break;
+#ifdef CONFIG_FEATURE_UDHCPC_IP
+ 		case OPTION_IP:	/* Works regardless of host byte order. */
+			if (type_p->flags & OPTION_PREFIX) {
+				dest += sprintprefix(dest, "", option);
+			} else {
+				dest += sprintip(dest, "", option);
+			}
+ 			break;
+#endif
 		case OPTION_BOOLEAN:
 			dest += sprintf(dest, *option ? "yes " : "no ");
 			break;