Add support to send the string 'PXEClient' as the Vendor class

identifier to the DHCP server.  Now you can check for this string
in your dhcp configuration to decide whether you will hand out a
lease to the client or not.

lib/libstand/bootp.c

@@ -37,6 +37,7 @@
  * SUCH DAMAGE.
  *
  * @(#) Header: bootp.c,v 1.4 93/09/11 03:13:51 leres Exp  (LBL)
+ * $FreeBSD$
  */
 
 #include <sys/types.h>
@@ -80,8 +81,9 @@ struct in_addr dhcp_serverip;
 
 /* Fetch required bootp infomation */
 void
-bootp(sock)
+bootp(sock, flag)
 	int sock;
+	int flag;
 {
 	struct iodesc *d;
 	register struct bootp *bp;
@@ -124,7 +126,19 @@ bootp(sock)
 	bp->bp_vend[4] = TAG_DHCP_MSGTYPE;
 	bp->bp_vend[5] = 1;
 	bp->bp_vend[6] = DHCPDISCOVER;
-	bp->bp_vend[7] = TAG_END;
+
+	/*
+	 * If we are booting from PXE, we want to send the string
+	 * 'PXEClient' to the DHCP server so you have the option of
+	 * only responding to PXE aware dhcp requests.
+	 */
+	if (flag & BOOTP_PXE) {
+		bp->bp_vend[7] = TAG_CLASSID;
+		bp->bp_vend[8] = 9;
+		bcopy("PXEClient", &bp->bp_vend[9], 9);
+		bp->bp_vend[18] = TAG_END;
+	} else
+		bp->bp_vend[7] = TAG_END;
 #else
 	bp->bp_vend[4] = TAG_END;
 #endif
@@ -161,7 +175,13 @@ bootp(sock)
 		bp->bp_vend[20] = 4;
 		leasetime = htonl(300);
 		bcopy(&leasetime, &bp->bp_vend[21], 4);
-		bp->bp_vend[25] = TAG_END;
+		if (flag & BOOTP_PXE) {
+			bp->bp_vend[25] = TAG_CLASSID;
+			bp->bp_vend[26] = 9;
+			bcopy("PXEClient", &bp->bp_vend[27], 9);
+			bp->bp_vend[36] = TAG_END;
+		} else
+			bp->bp_vend[25] = TAG_END;
 
 		expected_dhcpmsgtype = DHCPACK;
 

lib/libstand/bootp.h

@@ -18,6 +18,8 @@
  * University.  Carnegie Mellon makes no representations about the
  * suitability of this software for any purpose.  It is provided "as is"
  * without express or implied warranty.
+ *
+ * $FreeBSD$
  */
 
 
@@ -117,6 +119,12 @@ struct bootp {
 #define DHCPRELEASE 7
 #endif
 
+/*
+ * bootp flags
+ */
+#define	BOOTP_NONE		0x0000		/* No flags */
+#define	BOOTP_PXE		0x0001		/* Booting from PXE. */
+
 /*
  * "vendor" data permitted for CMU bootp clients.
  */

lib/libstand/net.h

@@ -114,7 +114,7 @@ ssize_t	sendrecv(struct iodesc *,
 			void *, size_t);
 
 /* bootp/DHCP */
-void	bootp(int);
+void	bootp(int, int);
 
 /* Utilities: */
 char	*ether_sprintf(u_char *);

sys/boot/common/dev_net.c

@@ -68,6 +68,7 @@
 #include <string.h>
 #include <net.h>
 #include <netif.h>
+#include <bootp.h>
 #include <bootparam.h>
 
 #include "dev_net.h"
@@ -217,7 +218,7 @@ net_getparams(sock)
      * use RARP and RPC/bootparam (the Sun way) to get them.
      */
     if (try_bootp)
-	bootp(sock);
+	bootp(sock, BOOTP_NONE);
     if (myip.s_addr != 0)
 	goto exit;
     if (debug)

sys/boot/i386/libi386/pxe.c

@@ -41,6 +41,7 @@
 #include <net.h>
 #include <netif.h>
 
+#include <bootp.h>
 #include <bootstrap.h>
 #include "btxv86.h"
 #include "pxe.h"
@@ -276,7 +277,7 @@ pxe_open(struct open_file *f, ...)
 		 * the proper information, fall back to the server
 		 * which brought us to life and a default rootpath.
 		 */
-		bootp(pxe_sock);
+		bootp(pxe_sock, BOOTP_PXE);
 		if (rootip.s_addr == 0)
 			rootip.s_addr = bootplayer.sip;
 		if (!rootpath[1])

sys/boot/i386/libi386/pxe.h

@@ -498,7 +498,9 @@ typedef struct {
 		uint8_t		d[BOOTP_DHCPVEND];	/* raw array of vendor/dhcp options */
 		struct {
 			uint8_t		magic[4];	/* DHCP magic cookie */
+#			ifndef		VM_RFC1048
 #			define		VM_RFC1048	0x63825363L	/* ? */
+#			endif
 			uint32_t	flags;		/* bootp flags/opcodes */
 			uint8_t		pad[56];	/* I don't think intel knows what a
 							   union does... */