[pxe] Remove pxe_set_cached_filename()

gPXE currently overwrites the filename stored in the cached DHCP
packets when a call to PXENV_TFTP_READ_FILE or PXENV_RESTART_TFTP is
made.  This code has existed for many years as a workaround for RIS,
which seemed to require that this be done.

pxe_set_cached_filename() causes problems with the Bootix NBP, and a
recent test demonstrates that RIS will complete successfully even with
pxe_set_cached_filename() removed.  There have been many changes to
the DHCP and PXE logic since this code was first added, and it is
quite plausible that it was masking a bug that no longer exists.

Reported-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
Debugged-by: Shao Miller <Shao.Miller@yrdsb.edu.on.ca>
Signed-off-by: Michael Brown <mcb30@etherboot.org>

src/arch/i386/include/pxe.h

@@ -149,6 +149,4 @@ extern struct net_device *pxe_netdev;
 
 extern void pxe_set_netdev ( struct net_device *netdev );
 
-extern void pxe_set_cached_filename ( const unsigned char *filename );
-
 #endif /* PXE_H */

src/arch/i386/interface/pxe/pxe_preboot.c

@@ -102,24 +102,6 @@ static struct pxe_dhcp_packet_creator pxe_dhcp_packet_creators[] = {
 static union pxe_cached_info __bss16_array ( cached_info, [NUM_CACHED_INFOS] );
 #define cached_info __use_data16 ( cached_info )
 
-/**
- * Set PXE cached TFTP filename
- *
- * @v filename		TFTP filename
- *
- * This is a bug-for-bug compatibility hack needed in order to work
- * with Microsoft Remote Installation Services (RIS).  The filename
- * used in a call to PXENV_RESTART_TFTP or PXENV_TFTP_READ_FILE must
- * be returned as the DHCP filename in subsequent calls to
- * PXENV_GET_CACHED_INFO.
- */
-void pxe_set_cached_filename ( const unsigned char *filename ) {
-	memcpy ( cached_info[CACHED_INFO_DHCPACK].dhcphdr.file, filename,
-		 sizeof ( cached_info[CACHED_INFO_DHCPACK].dhcphdr.file ) );
-	memcpy ( cached_info[CACHED_INFO_BINL].dhcphdr.file, filename,
-		 sizeof ( cached_info[CACHED_INFO_BINL].dhcphdr.file ) );
-}
-
 /**
  * UNLOAD BASE CODE STACK
  *
@@ -236,9 +218,6 @@ PXENV_EXIT_t pxenv_restart_tftp ( struct s_PXENV_TFTP_READ_FILE
 
 	DBG ( "PXENV_RESTART_TFTP " );
 
-	/* Intel bug-for-bug hack */
-	pxe_set_cached_filename ( restart_tftp->FileName );
-
 	/* Words cannot describe the complete mismatch between the PXE
 	 * specification and any possible version of reality...
 	 */

src/arch/i386/interface/pxe/pxe_tftp.c

@@ -171,9 +171,6 @@ static int pxe_tftp_open ( uint32_t ipaddress, unsigned int port,
 	struct in_addr address;
 	int rc;
 
-	/* Intel bug-for-bug hack */
-	pxe_set_cached_filename ( filename );
-
 	/* Reset PXE TFTP connection structure */
 	memset ( &pxe_tftp, 0, sizeof ( pxe_tftp ) );
 	xfer_init ( &pxe_tftp.xfer, &pxe_tftp_xfer_ops, NULL );
@@ -470,17 +467,6 @@ PXENV_EXIT_t pxenv_tftp_read ( struct s_PXENV_TFTP_READ *tftp_read ) {
  * value before calling this function in protected mode.  You cannot
  * call this function with a 32-bit stack segment.  (See the relevant
  * @ref pxe_x86_pmode16 "implementation note" for more details.)
- *
- * @note Microsoft's NTLDR assumes that the filename passed in via
- * s_PXENV_TFTP_READ_FILE::FileName will be stored in the "file" field
- * of the stored DHCPACK packet, whence it will be returned via any
- * subsequent calls to pxenv_get_cached_info().  Though this is
- * essentially a bug in the Intel PXE implementation (not, for once,
- * in the specification!), it is a bug that Microsoft relies upon, and
- * so we implement this bug-for-bug compatibility by overwriting the
- * filename stored DHCPACK packet with the filename passed in
- * s_PXENV_TFTP_READ_FILE::FileName.
- *
  */
 PXENV_EXIT_t pxenv_tftp_read_file ( struct s_PXENV_TFTP_READ_FILE
 				    *tftp_read_file ) {