From 60cff1d57e391e136b5d10c2dc2c89456f4d1df3 Mon Sep 17 00:00:00 2001
From: hpa <hpa>
Date: Tue, 9 Sep 2003 01:08:57 +0000
Subject: [PATCH] Add "ipappend 2"

---
 NEWS         |  3 +++
 pxelinux.asm | 22 +++++++++++++++++-----
 syslinux.doc | 25 ++++++++++++++++++++++---
 3 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/NEWS b/NEWS
index 10584aa..640313e 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,9 @@ Changes in 2.07:
 	* MEMDISK: Workaround for BIOSes which go into a snit when
 	  they get a RESET command for the floppy system when there is
 	  no floppy in the system.
+	* PXELINUX: Add "ipappend 2", which passes the hardware
+	  address of the boot interface to the kernel as a
+	  command-line option.
 
 Changes in 2.06:
 	* ALL: Fix problem that would occationally cause a
diff --git a/pxelinux.asm b/pxelinux.asm
index 3becef2..47feae2 100644
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -210,7 +210,7 @@ IPOption	resb 80			; ip= option buffer
 MACLen		resb 1			; MAC address len
 MACType		resb 1			; MAC address type
 MAC		resb 16			; Actual MAC address
-MACStr		resb 51			; MAC address as a string
+MACStr		resb 3*17		; MAC address as a string
 		alignb 32
 KernelName      resb FILENAME_MAX       ; Mangled name for kernel
 KernelCName     resb FILENAME_MAX	; Unmangled kernel name
@@ -894,14 +894,23 @@ config_scan:
 %define HAVE_SPECIAL_APPEND
 %macro	SPECIAL_APPEND 0
 		mov al,[IPAppend]		; ip=
-		and al,al
-		jz .noipappend
+		test al,01h			; IP append
+		jz .noipappend1
 		mov si,IPOption
 		mov cx,[IPOptionLen]
 		rep movsb
 		mov al,' '
 		stosb
-.noipappend:
+.noipappend1:
+		test al,02h
+		jz .noipappend2
+		mov si,bootif_str
+		mov cx,bootif_str_len
+		rep movsb
+		mov si,MACStr
+		call strcpy
+		mov byte [di-1],' '		; Replace null with space
+.noipappend2:
 %endmacro
 
 ; Unload PXE stack
@@ -2337,8 +2346,11 @@ cfgprefix_len	equ ($-cfgprefix)
 ;
 ; mem= and vga= are handled as normal 32-bit integer values
 initrd_cmd	db 'initrd='
-initrd_cmd_len	equ 7
+initrd_cmd_len	equ $-initrd_cmd
 
+; This one we make ourselves
+bootif_str	db 'BOOTIF='
+bootif_str_len	equ $-bootif_str
 ;
 ; Config file keyword table
 ;
diff --git a/syslinux.doc b/syslinux.doc
index 9948991..e217812 100644
--- a/syslinux.doc
+++ b/syslinux.doc
@@ -124,14 +124,33 @@ APPEND options...
         them.  This is the equivalent of the LILO "append" option.
 
 IPAPPEND flag_val			[PXELINUX only]
-	The IPAPPEND option is available only on PXELINUX, and
-	indicates (if the flag value is 1) that an option of the
-	following format should be generated and added:
+	The IPAPPEND option is available only on PXELINUX.  The
+	flag_val is an OR of the following options:
+
+	1: indicates that an option of the following format
+	should be generated and added to the kernel command line:
 
 		ip=<client-ip>:<boot-server-ip>:<gw-ip>:<netmask>
 
 	... based on the input from the DHCP/BOOTP or PXE boot server.
 
+	THE USE OF THIS OPTION IS NOT RECOMMENDED.  If you have to use
+	it, it is probably an indication that your network configuration
+	is broken.  Using just "ip=dhcp" on the kernel command line
+	is a preferrable option, or, better yet, run dhcpcd/dhclient,
+	from an initrd if necessary.
+
+	2: indicates that an option of the following format
+	should be generated and added to the kernel command line:
+
+		BOOTIF=<hardware-address-of-boot-interface>
+
+	... in dash-separated hexadecimal with leading hardware type
+	(same as for the configuration file; see pxelinux.doc.)
+
+	This allows an initrd program to determine from which
+	interface the system booted.
+
 LABEL label
   KERNEL image
   APPEND options...
-- 
2.7.4