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;;                                                                 ;;

;; Copyright (C) KolibriOS team 2004-2010. All rights reserved.    ;;

;; Distributed under terms of the GNU General Public License       ;;

;;                                                                 ;;

;;  ARP.INC                                                        ;;

;;                                                                 ;;

;;  Part of the tcp/ip network stack for KolibriOS                 ;;

;;                                                                 ;;

;;  Based on the work of [Johnny_B] and [smb]                      ;;

;;                                                                 ;;

;;    Written by hidnplayr@kolibrios.org                           ;;

;;                                                                 ;;

;;          GNU GENERAL PUBLIC LICENSE                             ;;

;;             Version 2, June- 1991                               ;;

;;                                                                 ;;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

$Revision: 2301 $

ARP_NO_ENTRY		equ 0

ARP_VALID_MAPPING	equ 1

ARP_AWAITING_RESPONSE	equ 2

ARP_RESPONSE_TIMEOUT	equ 3

ARP_REQUEST_TTL 	equ 31		; 20 s

ARP_ENTRY_TTL		equ 937 	; 600 s

ARP_REQ_OPCODE		equ 0x0100	; request

ARP_REP_OPCODE		equ 0x0200	; reply

ARP_TABLE_SIZE		equ 20		; Size of table

struct ARP_ENTRY

       .IP		dd  ?

       .MAC		dp  ?

       .Status		dw  ?

       .TTL		dw  ?

       .size:

ends

struct ARP_Packet

       .HardwareType	dw  ?

       .ProtocolType	dw  ?

       .HardwareSize	db  ?

       .ProtocolSize	db  ?

       .Opcode		dw  ?

       .SenderMAC	dp  ?

       .SenderIP	dd  ?

       .TargetMAC	dp  ?

       .TargetIP	dd  ?

       .size:

ends

align 4

uglobal

	NumARP		dd ?

	ARP_table	rb ARP_ENTRY.size * ARP_TABLE_SIZE

	ARP_PACKETS_TX	rd MAX_NET_DEVICES

	ARP_PACKETS_RX	rd MAX_NET_DEVICES

endg

;-----------------------------------------------------------------

;

; ARP_init

;

;  This function resets all ARP variables

;

;-----------------------------------------------------------------

macro ARP_init {

	xor	eax, eax

	mov	[NumARP], eax

	mov	edi, ARP_PACKETS_TX

	mov	ecx, 2*MAX_NET_DEVICES

	rep	stosd

}

;---------------------------------------------------------------------------

;

; ARP_decrease_entry_ttls

;

;---------------------------------------------------------------------------

macro ARP_decrease_entry_ttls {

local	.loop

local	.exit

; The TTL field is decremented every second, and is deleted when it reaches 0.

; It is refreshed every time a packet is received.

; If the TTL field is 0xFFFF it is a static entry and is never deleted.

; The status field can be the following values:

; 0x0000  entry not used

; 0x0001  entry holds a valid mapping

; 0x0002  entry contains an IP address, awaiting ARP response

; 0x0003  No response received to ARP request.

; The last status value is provided to allow the network layer to delete

; a packet that is queued awaiting an ARP response

	mov	ecx, [NumARP]

	test	ecx, ecx

	jz	.exit

	mov	esi, ARP_table

  .loop:

	cmp	[esi + ARP_ENTRY.TTL], 0xffff	; 0xffff = static entry

	je	.next

	dec	[esi + ARP_ENTRY.TTL]

	jz	.time_out

  .next:

	add	esi, ARP_ENTRY.size

	dec	ecx

	jnz	.loop

	jmp	.exit

  .time_out:

	cmp	[esi + ARP_ENTRY.Status], ARP_AWAITING_RESPONSE

	jz	.response_timeout

	push	esi ecx

	call	ARP_del_entry

	pop	ecx esi

	jmp	.next

  .response_timeout:

	mov	[esi + ARP_ENTRY.Status], ARP_RESPONSE_TIMEOUT

	mov	[esi + ARP_ENTRY.TTL], 10

	jmp	.next

  .exit:

}

;-----------------------------------------------------------------

;

; ARP_input

;

;  IN:  Pointer to buffer in [esp]

;       size of buffer in [esp+4]

;       packet size (without ethernet header) in ecx

;  OUT: /

;

;-----------------------------------------------------------------

align 4

ARP_input:

	DEBUGF	1,"ARP_Handler - start\n"

	cmp	ecx, ARP_Packet.size

	jb	.exit

;---------------------

; Handle Reply packets

	cmp	word [edx + ARP_Packet.Opcode], ARP_REP_OPCODE

	jne	.maybe_request

	DEBUGF	1,"ARP_Handler - it's a reply packet from %u.%u.%u.%u\n",\

	[edx + ARP_Packet.SenderIP]:1,[edx + ARP_Packet.SenderIP+1]:1,[edx + ARP_Packet.SenderIP+2]:1,[edx + ARP_Packet.SenderIP+3]:1,

	mov	ecx, [NumARP]

	test	ecx, ecx

	jz	.exit

	mov	eax, [edx + ARP_Packet.SenderIP]

	mov	esi, ARP_table

  .loop:

	cmp	[esi + ARP_ENTRY.IP], eax

	je	.gotit

	add	esi, ARP_ENTRY.size

	dec	ecx

	jnz	.loop

	jmp	.exit

  .gotit:

	DEBUGF	1,"ARP_Handler - found matching entry\n"

	cmp	[esi+ARP_ENTRY.TTL], 0xffff		; if it is a static entry, dont touch it