PXELINUX: no longer require a tsize option

No longer require a tsize option; this means handle
RRQ -> DATA as well as RRQ -> OACK.

diff --git a/pxelinux.asm b/pxelinux.asm
index 8bb87c2..aca0c85 100644 (file)
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -1152,8 +1152,10 @@ searchdir:
                mov si,[bp-6]                   ; TFTP pointer
                mov bx,[bp-8]                   ; TID
 
+               ; Make sure the packet actually came from the server
+               ; This is technically not to the TFTP spec?
                mov eax,[si+tftp_remoteip]
-               cmp [pxe_udp_read_pkt.sip],eax  ; This is technically not to the TFTP spec?
+               cmp [pxe_udp_read_pkt.sip],eax
                jne .no_packet
 
                ; Got packet - reset timeout
@@ -1170,7 +1172,7 @@ searchdir:
                ; Default blksize unless blksize option negotiated
                mov word [si+tftp_blksize], TFTP_BLOCKSIZE
 
-               mov cx,[pxe_udp_read_pkt.buffersize]
+               movzx ecx,word [pxe_udp_read_pkt.buffersize]
                sub cx,2                ; CX <- bytes after opcode
                jb .failure             ; Garbled reply
 
@@ -1180,13 +1182,21 @@ searchdir:
                cmp ax, TFTP_ERROR
                je .bailnow             ; ERROR reply: don't try again
 
+               ; If the server doesn't support any options, we'll get
+               ; a DATA reply instead of OACK.  Stash the data in
+               ; the file buffer and go with the default value for
+               ; all options...
+               cmp ax, TFTP_DATA
+               je .no_oack
+
                cmp ax, TFTP_OACK
-               jne .no_tsize
+               jne .err_reply          ; Unknown packet type
 
                ; Now we need to parse the OACK packet to get the transfer
-               ; size.  SI -> first byte of options; CX -> byte count
+               ; and packet sizes.
+               ;  SI -> first byte of options; [E]CX -> byte count
 .parse_oack:
-               jcxz .no_tsize                  ; No options acked
+               jcxz .done_pkt                  ; No options acked
 .get_opt_name:
                mov di,si
                mov bx,si
@@ -1255,9 +1265,7 @@ searchdir:
                pop si                  ; Junk
                pop si                  ; We want the packet ptr in SI
 
-               mov eax,[si+tftp_filesize]
-               cmp eax,-1
-               jz .no_tsize
+               mov eax,[si+tftp_bytesleft]
                mov edx,eax
                shr edx,16              ; DX:AX == EAX
 
@@ -1272,7 +1280,33 @@ searchdir:
                pop es
                ret
 
-.no_tsize:
+
+.no_oack:      ; We got a DATA packet, meaning no options are
+               ; suported.  Save the data away and consider the length
+               ; undefined, *unless* this is the only data packet...
+               mov bx,[bp-6]           ; File pointer
+               sub cx,2                ; Too short?
+               jb .failure
+               lodsw                   ; Block number
+               cmp ax,1
+               jne .failure
+               mov [bx+tftp_lastpkt],ax
+               cmp cx,TFTP_BLOCKSIZE
+               ja .err_reply           ; Corrupt...
+               je .unknown_size
+               mov [bx+tftp_filesize],ecx
+.unknown_size: mov [bx+tftp_bytesleft],cx
+               mov ax,pktbuf_seg
+               push es
+               mov es,ax
+               mov di,tftp_pktbuf
+               mov [bx+tftp_dataptr],di
+               add cx,3
+               shr cx,2
+               rep movsd
+               pop es
+               jmp .done_pkt
+
 .err_reply:    ; Option negotiation error.  Send ERROR reply.
                ; ServerIP and gateway are already programmed in
                mov si,[bp-6]