From 16f5c17703a99c5fdef488274a037962b2fb72c1 Mon Sep 17 00:00:00 2001
From: hpa <hpa>
Date: Tue, 25 Nov 2003 04:12:43 +0000
Subject: [PATCH] - Handle ARP requests while idle in pxelinux - Actually
 reallocate sockets correctly in pxelinux

---
 NEWS         |  5 +++++
 conio.inc    |  4 +++-
 isolinux.asm |  7 ++++++
 ldlinux.asm  |  7 ++++++
 pxelinux.asm | 73 ++++++++++++++++++++++++++++++++++++++++++++++++------------
 ui.inc       |  1 +
 6 files changed, 82 insertions(+), 15 deletions(-)

diff --git a/NEWS b/NEWS
index c796e80..26d8267 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,11 @@ Changes in 2.08:
 	  than just pressing Enter.
 	* Fix bugs in the COMBOOT/COM32 command-line parsing.  APPEND
 	  now works with COMBOOT/COM32 images.
+	* PXELINUX: Poll for ARP requests while sitting at the
+	  prompt.  This makes some boot servers a lot less unhappy.
+	* PXELINUX: Actually free sockets when we get a failure
+	  (including file not found.)  This bug would cause us to run
+	  out of sockets and thus "go deaf" after a while.
 
 Changes in 2.07:
 	* MEMDISK: Workaround for BIOSes which go into a snit when
diff --git a/conio.inc b/conio.inc
index 7dc1572..58c7e3a 100644
--- a/conio.inc
+++ b/conio.inc
@@ -319,7 +319,9 @@ pollchar:
 ; getchar: Read a character from keyboard or serial port
 ;
 getchar:
-.again:		mov ah,1		; Poll keyboard
+.again:
+		DO_IDLE
+		mov ah,1		; Poll keyboard
 		int 16h
 		jnz .kbd		; Keyboard input?
 		mov bx,[SerialPort]
diff --git a/isolinux.asm b/isolinux.asm
index 7b92fd4..e8e9806 100644
--- a/isolinux.asm
+++ b/isolinux.asm
@@ -41,6 +41,13 @@ SECTORSIZE_LG2	equ 11			; 2048 bytes/sector (El Torito requirement)
 SECTORSIZE	equ (1 << SECTORSIZE_LG2)
 
 ;
+; This is what we need to do when idle
+;
+%macro	DO_IDLE 0
+	; Nothing
+%endmacro
+
+;
 ; The following structure is used for "virtual kernels"; i.e. LILO-style
 ; option labels.  The options we permit here are `kernel' and `append
 ; Since there is no room in the bottom 64K for all of these, we
diff --git a/ldlinux.asm b/ldlinux.asm
index b39c905..251b0f1 100644
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -46,6 +46,13 @@ retry_count	equ 6			; How patient are we with the disk?
 %assign HIGHMEM_SLOP 0			; Avoid this much memory near the top
 
 ;
+; This is what we need to do when idle
+;
+%macro	DO_IDLE 0
+	; Nothing
+%endmacro
+
+;
 ; The following structure is used for "virtual kernels"; i.e. LILO-style
 ; option labels.  The options we permit here are `kernel' and `append
 ; Since there is no room in the bottom 64K for all of these, we
diff --git a/pxelinux.asm b/pxelinux.asm
index fd2877a..1a2f488 100644
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -53,6 +53,13 @@ TFTP_BLOCKSIZE	equ (1 << TFTP_BLOCKSIZE_LG2)
 %assign USE_PXE_PROVIDED_STACK 1	; Use stack provided by PXE?
 
 ;
+; This is what we need to do when idle
+;
+%macro	DO_IDLE 0
+	call check_for_arp
+%endmacro
+
+;
 ; TFTP operation codes
 ;
 TFTP_RRQ	equ htons(1)		; Read request
@@ -1230,8 +1237,7 @@ searchdir:
 		mov [pxe_udp_read_pkt.status],byte 0
 		mov [pxe_udp_read_pkt.buffer],di
 		mov [pxe_udp_read_pkt.buffer+2],ds
-		mov di,packet_buf_size
-		mov [pxe_udp_read_pkt.buffersize],di
+		mov word [pxe_udp_read_pkt.buffersize],packet_buf_size
 		mov eax,[MyIP]
 		mov [pxe_udp_read_pkt.dip],eax
 		mov [pxe_udp_read_pkt.lport],bx
@@ -1369,6 +1375,7 @@ searchdir:
 		and eax,eax		; Set ZF depending on file size
 		pop bp			; Junk
 		pop bp			; Junk (retry counter)
+		jz .error_si		; ZF = 1 need to free the socket
 		pop bp
 		pop es
 		ret
@@ -1390,8 +1397,7 @@ searchdir:
 		call writestr
 		jmp kaboom
 
-.bailnow:	add sp,byte 8		; Immediate error - no retry
-		jmp short .error
+.bailnow:	mov word [bp-2],1	; Immediate error - no retry
 
 .failure:	pop bx			; Junk
 		pop bx
@@ -1400,7 +1406,9 @@ searchdir:
 		dec ax			; Retry counter
 		jnz .sendreq		; Try again
 
-.error:		xor si,si		; ZF <- 1
+.error:		mov si,bx		; Socket pointer
+.error_si:				; Socket pointer already in SI
+		call free_socket	; ZF <- 1, SI <- 0
 		pop bp
 		pop es
 		ret
@@ -1450,6 +1458,22 @@ allocate_socket:
 		ret
 
 ;
+; Free socket: socket in SI; return SI = 0, ZF = 1 for convenience
+;
+free_socket:
+		push es
+		pusha
+		xor ax,ax
+		mov es,ax
+		mov di,si
+		mov cx,tftp_clear_words
+		rep stosw
+		popa
+		pop es
+		xor si,si
+		ret
+
+;
 ; strcpy: Copy DS:SI -> ES:DI up to and including a null byte
 ;
 strcpy:		push ax
@@ -1659,15 +1683,7 @@ getfssec:	push si
 
 		; The socket is closed and the buffer drained
 		; Close socket structure and re-init for next user
-		push es
-		push ds
-		pop es
-		mov di,si
-		; ax = 0
-		mov cx,tftp_clear_words
-		rep stosw
-		pop es
-		xor si,si
+		call free_socket
 		stc
 .bytes_left:
 		ret
@@ -2271,6 +2287,35 @@ genipopt:
 		popad
 		ret
 
+;
+; Call the receive loop while idle.  This is done mostly so we can respond to
+; ARP messages, but perhaps in the future this can be used to do network
+; console.
+;
+check_for_arp:
+		pushad
+		push ds
+		push es
+		mov ax,cs
+		mov ds,ax
+		mov es,ax
+		mov di,packet_buf
+		mov [pxe_udp_read_pkt.status],al	; 0
+		mov [pxe_udp_read_pkt.buffer],di
+		mov [pxe_udp_read_pkt.buffer+2],ds
+		mov word [pxe_udp_read_pkt.buffersize],packet_buf_size
+		mov eax,[MyIP]
+		mov [pxe_udp_read_pkt.dip],eax
+		mov [pxe_udp_read_pkt.lport],ax		; 0
+		mov di,pxe_udp_read_pkt
+		mov bx,PXENV_UDP_READ
+		call pxenv
+		; Ignore result...
+		pop es
+		pop ds
+		popad
+		ret
+
 ; -----------------------------------------------------------------------------
 ;  Common modules
 ; -----------------------------------------------------------------------------
diff --git a/ui.inc b/ui.inc
index 6e05b9b..cbb451c 100644
--- a/ui.inc
+++ b/ui.inc
@@ -59,6 +59,7 @@ tick_loop:	push dx
 		cmp dx,ax			; Has the timer advanced?
 		je tick_loop
 		pop cx
+		DO_IDLE
 		loop time_loop			; If so, decrement counter
 
 		; Timeout!!!!
-- 
2.7.4