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;;  This file contains the following:                           ;;

;;   arp_request - Sends an ARP request on the ethernet         ;;

;;   arp_handler - Called when an ARP packet is received        ;;

;;  Changes history:                                            ;;

;;   22.09.2003 - [Mike Hibbett] : mikeh@oceanfree.net          ;;

	ret

;   Function

;   Operation: see Opcode's constants below

;  OUT:

;   EAX = Returned value depends on opcodes, more detailed see below

;

;***************************************************************************

;Opcode's constants

ARP_TABLE_ADD		      equ  1

ARP_TABLE_IP_TO_MAC	      equ  5

EXTRA_IS_ARP_PACKET_PTR  equ  0   ;if Extra contain pointer to ARP_Packet

EXTRA_IS_ARP_ENTRY_PTR	 equ  -1  ;if Extra contain pointer to ARP_ENTRY

align 4

proc arp_table_manager stdcall uses ebx esi edi ecx edx, Opcode:DWORD,Index:DWORD,Extra:DWORD

    mov     ebx, ARPTable  ;ARPTable base

    mov     ecx, dword[NumARP]	       ;ARP-entries counter

    mov     eax, dword[Opcode]

    DEBUGF 1,"ARP table manager opcode:%u numARP:%u\n",eax,ecx

    cmp     eax, ARP_TABLE_ADD

    je	    .add

    cmp     eax, ARP_TABLE_IP_TO_MAC

    je	    .ip_to_mac

    jmp     .exit     ;if unknown opcode

;;BEGIN ADD

;;Description: it adds an entry in the table. If ARP-table already

;;             contains same IP, it will be updated.

;;IN:   Operation: ARP_TABLE_ADD

;;      Index: specifies what contains Extra-parameter

;;      Extra: if Index==EXTRA_IS_ARP_Packet_PTR,

;;             then Extra contains pointer to ARP_Packet,

;;             otherwise Extra contains pointer to ARP_ENTRY

;;OUT:

;;  EAX=index of entry, that has been added

;;

.add:

    DEBUGF 1,"1"

    sub     esp, ARP_ENTRY.size   ;Allocate ARP_ENTRY_SIZE byte in stack

    mov     esi, [Extra]   ;pointer

    mov     edi, [Index]   ;opcode

    cmp     edi, EXTRA_IS_ARP_PACKET_PTR

    je	    .ARP_Packet_to_entry ;if Extra contain ptr to ARP_Packet and we have to form arp-entry

				 ;else it contain ptr to arp-entry

    DEBUGF 1,"2"

    cld

	  ; esi already has been loaded

    mov     edi, esp	  ;ebx + eax=ARPTable_base + ARP-entry_base(where we will add)

    mov     ecx,ARP_ENTRY.size/2  ;ARP_ENTRY_SIZE must be even number!!!

    rep     movsw    ;copy

    jmp     .search

  .ARP_Packet_to_entry:

    DEBUGF 1,"3"

    mov     edx, dword[esi + ARP_Packet.SenderIP] ;esi=base of ARP_Packet

    mov     [esp + ARP_ENTRY.IP], edx

    cld

    lea     esi, [esi + ARP_Packet.SenderMAC]

    lea     edi, [esp + ARP_ENTRY.MAC]

    movsd

    movsw

    mov     word[esp + ARP_ENTRY.Status], ARP_VALID_MAPPING  ; specify the type - a valid entry

    mov     word[esp + ARP_ENTRY.TTL], 0x0E10	 ; = 1 hour

  .search:

    DEBUGF 1,"4"

    mov     edx, dword[esp + ARP_ENTRY.IP]  ;edx=IP-address, which we'll search

    mov     ecx, dword[NumARP]		    ;ecx=ARP-entries counter

    jecxz   .add_to_end 		    ;if ARP-entries number == 0

    imul    eax, ecx, ARP_ENTRY.size	    ;eax=current table size(in bytes)

  @@:

    sub     eax, ARP_ENTRY.size

    loopnz  @b

;    jz      .replace       ; found, replace existing entry, ptr to it is in eax

  .add_to_end:

;

;    DEBUGF 1,"5\n"

;    ;else add to end

;    or      eax,-1    ;set eax=0xFFFFFFFF if adding is impossible

;    mov     ecx, dword[NumARP]

;    cmp     ecx, ARP_TABLE_SIZE

;    je      .add_exit   ;if arp-entries number is equal to arp-table maxsize

;    imul    eax, dword[NumARP], ARP_ENTRY.size ;eax=ptr to end of ARPTable

;    inc     dword [NumARP]    ;increase ARP-entries counter

;  .replace:

    DEBUGF 1,"Updating ARP entry: %x-%x-%x-%x-%x-%x = %u.%u.%u.%u to slot:%u\n",\

    [esp + ARP_ENTRY.MAC]:2,[esp + ARP_ENTRY.MAC+1]:2,[esp + ARP_ENTRY.MAC+2]:2,[esp + ARP_ENTRY.MAC+3]:2,[esp + ARP_ENTRY.MAC+4]:2,[esp + ARP_ENTRY.MAC+5]:2,\

    [esp + ARP_ENTRY.IP]:1,[esp + ARP_ENTRY.IP+1]:1,[esp + ARP_ENTRY.IP+2]:1,[esp + ARP_ENTRY.IP+3]:1,eax

    cld

    mov     esi, esp		  ;esp=base of ARP-entry, that will be added

    lea     edi, [ebx + eax]	  ;ebx + eax=ARPTable_base + ARP-entry_base(where we will add)

    mov     ecx,ARP_ENTRY.size/2  ;ARP_ENTRY_SIZE must be even number!!!

    rep     movsw

    mov     ecx, ARP_ENTRY.size

    xor     edx, edx  ;"div" takes operand from EDX:EAX

    div     ecx       ;eax=index of entry, which has been added

.add_exit:

    add     esp, ARP_ENTRY.size   ;free stack

    jmp     .exit

;;END ADD

;;BEGIN IP_TO_MAC

;;Description: it gets an IP from Index, scans each entry in the table and writes

;;             MAC, that relates to specified IP, into buffer specified in Extra.

;;             And if it cannot find an IP-address in the table, it does an ARP-request of that.

;;IN:   Operation: ARP_TABLE_IP_TO_MAC

;;      Index: IP that should be transformed into MAC

;;      Extra: pointer to buffer where will be written the MAC-address.

;;OUT:

;;  EAX=ARP table entry status code.

;;      If EAX==ARP_NO_ENTRY, IP isn't found in the table and we have sent the request.

;;      If EAX==ARP_AWAITING_RESPONSE, we wait the response from remote system.

;;      If EAX==ARP_RESPONSE_TIMEOUT, remote system not responds too long.

;;      If EAX==ARP_VALID_MAPPING, all is ok, we've got a true MAC.

;;

;;  If MAC will equal to a zero, in the buffer. It means, that IP-address was not yet

;;  resolved, or that doesn't exist. I recommend you, to do at most 3-5 calls of this

;;  function with 1sec delay. sure, only if it not return a valid MAC after a first call.

;;  

.ip_to_mac:

    DEBUGF 1,"Trying to find MAC for %u.%u.%u.%u\n",[Index]:1,[Index+1]:1,[Index+2]:1,[Index+3]:1

    xor     eax, eax

    ; first, check destination IP to see if it is on 'this' network.

    ; if ( destIP & subnet_mask == stack_ip & subnet_mask )

    ;   destination is local

    ; else

    mov     eax, [Index]       ;eax=required IP

    and     esi, [SUBNET_LIST+edx]

    je	    @f	      ;if we and target IP are located in the same network

    mov     [Index], eax

    DEBUGF 1,"IP is not on subnet, using %u.%u.%u.%u instead\n",[Index]:1,[Index+1]:1,[Index+2]:1,[Index+3]:1

    cmp     dword[NumARP], 0

    mov     ecx, dword[NumARP]

    imul    esi, ecx, ARP_ENTRY.size  ;esi=current ARP-table size

  @@:

    sub     esi, ARP_ENTRY.size

    cmp     [ebx + esi + ARP_ENTRY.IP], eax	    ; ebx=ARPTable base

    loopnz  @b			     ; Return back if non match

    ; Return the entry status in eax

    DEBUGF 1,"MAC found:  %x-%x-%x-%x-%x-%x status:%x in slot:%u\n",\

    movsd

    jmp     .exit

  .ip_to_mac_send_request:

;;; TODO: get device number ! (in edx)

    xor     edx, edx

    mov     edx, [ETH_DRV_LIST + 4*edx]

    lea     ecx, [edx + ETH_DEVICE.mac]

    stdcall arp_request,[Index],[IP_LIST+edx],ecx  ;TargetIP,SenderIP_ptr,SenderMAC_ptr

    mov     eax, ARP_NO_ENTRY

    jmp     .exit

.exit:

    ret

endp

;***************************************************************************

;   Function

;      arp_request  [by Johnny_B]

;

;   Description

;      Sends an ARP request on the ethernet

;     SenderIP_ptr  : POINTER to sender's IP address(our system's address)

;     SenderMAC_ptr : POINTER to sender's MAC address(our system's address)

;   OUT:

;     EAX=0 (if all is ok), otherwise EAX is not defined

;

;      EBX,ESI,EDI will be saved

;

;***************************************************************************

    TargetIP:DWORD, SenderIP_ptr:DWORD, SenderMAC_ptr:DWORD

    DEBUGF 1,"Create ARP request\n"

    stdcall kernel_alloc, 60  ; minimum eth packet size

    jz	    .exit

    mov     ebx, eax

    mov     word [ebx + ETH_FRAME.Data + ARP_Packet.HardwareType], 0x0100 ;Ethernet

    mov     word [ebx + ETH_FRAME.Data + ARP_Packet.ProtocolType], 0x0008 ;IP

    mov     byte [ebx + ETH_FRAME.Data + ARP_Packet.HardwareSize], 0x06   ;MAC-addr length

    mov     byte [ebx + ETH_FRAME.Data + ARP_Packet.ProtocolSize], 0x04   ;IP-addr length

    mov     word [ebx + ETH_FRAME.Data + ARP_Packet.Opcode], 0x0100	  ;Request

    DEBUGF 1,"1"

    cld

    mov     esi, [SenderMAC_ptr]

    lea     edi, [ebx + ETH_FRAME.Data + ARP_Packet.SenderMAC]	     ;Our MAC-addr

    movsd

    movsw

    DEBUGF 1,"2"

;    movsd

    DEBUGF 1,"3"

    stosd

    DEBUGF 1,"5"

    mov     dword [ebx + ETH_FRAME.Data + ARP_Packet.TargetIP], esi   ;Required IP-addr(we get it as function parameter)

    DEBUGF 1,"6"

    mov     esi, [SenderMAC_ptr]

    movsd

    DEBUGF 1,"7"

    DEBUGF 1,"8"

;;; TODO: get device number in edx !!

	dec	dword[NumARP] ;decrease arp-entries counter

;        DEBUGF  1,"ETH_ARP_Handler - request for %u.%u.%u.%u\n",[edi+0]:1,[edi+1]:1,[edi+2]:1,[edi+3]:1