$Revision: 425 $
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; ARP.INC
;;
;; Address Resolution Protocol
;;
;; Last revision: 10.11.2006
;;
;; This file contains the following:
;; arp_table_manager - Manages an ARPTable
;; 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
;; 11.11.2006 - [Johnny_B] and [smb]
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
ARP_NO_ENTRY equ 0
ARP_VALID_MAPPING equ 1
ARP_AWAITING_RESPONSE equ 2
ARP_RESPONSE_TIMEOUT equ 3
struc ARP_ENTRY ;=14 bytes
{ .IP dd ? ;+00
.MAC dp ? ;+04
.Status dw ? ;+10
.TTL dw ? ;+12 : ( in seconds )
}
virtual at 0
ARP_ENTRY ARP_ENTRY
end virtual
; 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
; The follow is the ARP Table.
; This table must be manually updated and the kernel recompilied if
; changes are made to it.
; Empty entries are filled with zeros
ARP_ENTRY_SIZE equ 14 ; Number of bytes per entry
ARP_TABLE_SIZE equ 20 ; Size of table
ARP_TABLE_ENTRIES equ 0 ; Number of static entries in the table
;TO ADD A STATIC ENTRY, DONT FORGET, PUT "ARPTable" from "uglobal" to "iglobal"!!!
;AND ALSO - IP and MAC have net byte-order, BUT STATUS AND TTL HAVE A MIRROR BYTE-ORDER!!!
uglobal
ARPTable:
;example, static entry -> db 11,22,33,44, 0x11,0x22,0x33,0x44,0x55,0x66, 0x01,0x00, 0xFF,0xFF
times ( ARP_TABLE_SIZE - ARP_TABLE_ENTRIES ) * ARP_ENTRY_SIZE db 0
endg
iglobal
NumARP: dd ARP_TABLE_ENTRIES
ARPTable_ptr dd ARPTable ;pointer to ARPTable
endg
ARP_REQ_OPCODE equ 0x0100 ;request
ARP_REP_OPCODE equ 0x0200 ;reply
struc ARP_PACKET
{ .HardwareType dw ? ;+00
.ProtocolType dw ? ;+02
.HardwareSize db ? ;+04
.ProtocolSize db ? ;+05
.Opcode dw ? ;+06
.SenderMAC dp ? ;+08
.SenderIP dd ? ;+14
.TargetMAC dp ? ;+18
.TargetIP dd ? ;+24
}
virtual at 0
ARP_PACKET ARP_PACKET
end virtual
;***************************************************************************
; Function
; arp_table_manager [by Johnny_B]
;
; Description
; Does a most required operations with ARP-table
; IN:
; Operation: see Opcode's constants below
; Index: Index of entry in the ARP-table
; Extra: Extra parameter for some Opcodes
; OUT:
; EAX = Returned value depends on opcodes, more detailed see below
;
;***************************************************************************
;Opcode's constants
ARP_TABLE_ADD equ 1
ARP_TABLE_DEL equ 2
ARP_TABLE_GET equ 3
ARP_TABLE_GET_ENTRIES_NUMBER equ 4
ARP_TABLE_IP_TO_MAC equ 5
ARP_TABLE_TIMER equ 6
;Index's constants
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, dword[ARPTable_ptr] ;ARPTable base
mov ecx, dword[NumARP] ;ARP-entries counter
mov eax, dword[Opcode]
cmp eax, ARP_TABLE_TIMER
je .timer
cmp eax, ARP_TABLE_ADD
je .add
cmp eax, ARP_TABLE_DEL
je .del
cmp eax, ARP_TABLE_GET
je .get
cmp eax, ARP_TABLE_IP_TO_MAC
je .ip_to_mac
cmp eax, ARP_TABLE_GET_ENTRIES_NUMBER
je .get_entries_number
jmp .exit ;if unknown opcode
;;BEGIN TIMER
;;Description: it must be callback every second. It is responsible for removing expired routes.
;;IN: Operation: ARP_TABLE_TIMER
;; Index: must be zero
;; Extra: must be zero
;;OUT:
;; EAX=not defined
;;
.timer:
test ecx, ecx
jz .exit ;if NumARP=0 nothing to do
sub ecx, ARP_TABLE_ENTRIES ;ecx=dynamic entries number
jz .exit ;if NumARP=number of static entries then exit
add ebx, ARP_TABLE_ENTRIES*ARP_ENTRY_SIZE ;ebx=dynamic entries base
.timer_loop:
movsx esi, word [ebx + ARP_ENTRY.TTL]
cmp esi, 0xFFFFFFFF
je .timer_loop_end ;if TTL==0xFFFF then it's static entry
test esi, esi
jnz .timer_loop_end_with_dec ;if TTL!=0
; Ok, TTL is 0
;if Status==AWAITING_RESPONSE and TTL==0
;then we have to change it to ARP_RESPONSE_TIMEOUT
cmp word [ebx + ARP_ENTRY.Status], ARP_AWAITING_RESPONSE
jne @f
mov word [ebx + ARP_ENTRY.Status], ARP_RESPONSE_TIMEOUT
mov word [ebx + ARP_ENTRY.TTL], word 0x000A ;10 sec
jmp .timer_loop_end
@@:
;if TTL==0 and Status==VALID_MAPPING, we have to delete it
;if TTL==0 and Status==RESPONSE_TIMEOUT, delete too
mov esi, dword[NumARP]
sub esi, ecx ;esi=index of entry, will be deleted
stdcall arp_table_manager,ARP_TABLE_DEL,esi,0 ;opcode,index,extra
jmp .timer_loop_end
.timer_loop_end_with_dec:
dec word [ebx + ARP_ENTRY.TTL] ;decrease TTL
.timer_loop_end:
add ebx, ARP_ENTRY_SIZE
loop .timer_loop
jmp .exit
;;END TIMER
;;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:
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
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:
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:
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
cmp dword[ebx + eax + ARP_ENTRY.IP], edx
loopnz @b
jz .replace ; found, replace existing entry, ptr to it is in eax
.add_to_end:
;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:
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 DEL
;;Description: it deletes an entry in the table.
;;IN: Operation: ARP_TABLE_DEL
;; Index: index of entry, that should be deleted
;; Extra: must be zero
;;OUT:
;; EAX=not defined
;;
.del:
mov esi, [Index]
imul esi, ARP_ENTRY_SIZE
mov ecx, (ARP_TABLE_SIZE - 1) * ARP_ENTRY_SIZE
sub ecx, esi
lea edi, [ebx + esi] ;edi=ptr to entry that should be deleted
lea esi, [edi + ARP_ENTRY_SIZE] ;esi=ptr to next entry
shr ecx,1 ;ecx/2 => ARP_ENTRY_SIZE MUST BE EVEN NUMBER!
cld
rep movsw
dec dword[NumARP] ;decrease arp-entries counter
jmp .exit
;;END DEL
;;BEGIN GET
;;Description: it reads an entry of table into buffer.
;;IN: Operation: ARP_TABLE_GET
;; Index: index of entry, that should be read
;; Extra: pointer to buffer for reading(size must be equal to ARP_ENTRY_SIZE)
;;OUT:
;; EAX=not defined
;;
.get:
mov esi, [Index]
imul esi, ARP_ENTRY_SIZE ;esi=ptr to required ARP_ENTRY
mov edi, [Extra] ;edi=buffer for reading
mov ecx, ARP_ENTRY_SIZE/2 ; must be even number!!!
cld
rep movsw
jmp .exit
;;END GET
;;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:
xor eax, eax
mov edi, dword[Extra]
cld
stosd
stosw
cmp dword[NumARP], 0
je .ip_to_mac_send_request ;if ARP-table not contain an entries, we have to request IP.
;EAX will be containing a zero, it's equal to ARP_NO_ENTRY
; first, check destination IP to see if it is on 'this' network.
; The test is:
; if ( destIP & subnet_mask == stack_ip & subnet_mask )
; destination is local
; else
; destination is remote, so pass to gateway
mov eax, [Index] ;eax=required IP
mov esi, eax
and esi, [subnet_mask]
mov ecx, [stack_ip]
and ecx, [subnet_mask]
cmp esi, ecx
je @f ;if we and target IP are located in the same network
mov eax, [gateway_ip]
@@:
mov ecx, dword[NumARP]
imul esi, ecx, ARP_ENTRY_SIZE ;esi=current ARP-table size
@@:
sub esi, ARP_ENTRY_SIZE
cmp [ebx + esi], eax ; ebx=ARPTable base
loopnz @b ; Return back if non match
jnz .ip_to_mac_send_request ; and request IP->MAC if none found in the table
; Return the entry status in eax
movzx eax, word[ebx + esi + ARP_ENTRY.Status]
; esi holds index
cld
lea esi, [ebx + esi + ARP_ENTRY.MAC]
mov edi, [Extra] ;edi=ptr to buffer for write MAC
movsd
movsw
jmp .exit
.ip_to_mac_send_request:
stdcall arp_request,[Index],stack_ip,node_addr ;TargetIP,SenderIP_ptr,SenderMAC_ptr
mov eax, ARP_NO_ENTRY
jmp .exit
;;END IP_TO_MAC
;;BEGIN GET_ENTRIES_NUMBER
;;Description: returns an ARP-entries number in the ARPTable
;;IN: Operation: ARP_TABLE_GET_ENTRIES_NUMBER
;; Index: must be zero
;; Extra: must be zero
;;OUT:
;; EAX=ARP-entries number in the ARPTable
.get_entries_number:
mov eax, dword[NumARP]
jmp .exit
;;END GET_ENTRIES_NUMBER
.exit:
ret
endp
;***************************************************************************
; Function
; arp_handler
;
; Description
; Called when an ARP packet is received on the ethernet
; Header + Data is in Ether_buffer[]
; It looks to see if the packet is a request to resolve this Hosts
; IP address. If it is, send the ARP reply packet.
; This Hosts IP address is in dword [stack_ip] ( in network format )
; This Hosts MAC address is in node_addr[6]
; All registers may be destroyed
;
;***************************************************************************
arp_handler:
; Is this a REQUEST?
; Is this a request for My Host IP
; Yes - So construct a response message.
; Send this message to the ethernet card for transmission
stdcall arp_table_manager,ARP_TABLE_ADD,EXTRA_IS_ARP_PACKET_PTR,ETH_FRAME.Data + ARP_PACKET
inc dword[arp_rx_count] ;increase ARP-packets counter
cmp word[ETH_FRAME.Data + ARP_PACKET.Opcode], ARP_REQ_OPCODE ; Is this a request packet?
jne .exit ; No - so exit
mov eax, [stack_ip]
cmp eax, dword[ETH_FRAME.Data + ARP_PACKET.TargetIP] ; Is it looking for my IP address?
jne .exit ; No - so quit now
; OK, it is a request for my MAC address. Build the frame and send it
; We can reuse the packet.
mov word[ETH_FRAME.Data + ARP_PACKET.Opcode], ARP_REP_OPCODE
cld
mov esi, ETH_FRAME.Data + ARP_PACKET.SenderMAC
mov edi, ETH_FRAME.Data + ARP_PACKET.TargetMAC
movsd
movsw
mov esi, ETH_FRAME.Data + ARP_PACKET.SenderIP
mov edi, ETH_FRAME.Data + ARP_PACKET.TargetIP
movsd
mov esi, node_addr
mov edi, ETH_FRAME.Data + ARP_PACKET.SenderMAC
movsd
movsw
mov esi, stack_ip
mov edi, ETH_FRAME.Data + ARP_PACKET.SenderIP
movsd
; Now, send it!
mov edi, ETH_FRAME.Data + ARP_PACKET.TargetMAC ;ptr to destination MAC address
mov bx, ETHER_ARP ;type of protocol
mov ecx, 28 ;data size
mov esi, ETH_FRAME.Data + ARP_PACKET ;ptr to data
call dword [drvr_transmit] ;transmit packet
.exit:
ret
;***************************************************************************
; Function
; arp_request [by Johnny_B]
;
; Description
; Sends an ARP request on the ethernet
; IN:
; TargetIP : requested IP address
; 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
;
;***************************************************************************
proc arp_request stdcall uses ebx esi edi,\
TargetIP:DWORD, SenderIP_ptr:DWORD, SenderMAC_ptr:DWORD
inc dword[arp_tx_count] ; increase counter
sub esp, 28 ; allocate memory for ARP_PACKET
mov word[esp + ARP_PACKET.HardwareType],0x0100 ;Ethernet
mov word[esp + ARP_PACKET.ProtocolType],0x0008 ;IP
mov byte[esp + ARP_PACKET.HardwareSize],0x06 ;MAC-addr length
mov byte[esp + ARP_PACKET.ProtocolSize],0x04 ;IP-addr length
mov word[esp + ARP_PACKET.Opcode],0x0100 ;Request
cld
mov esi,[SenderMAC_ptr]
lea edi,[esp + ARP_PACKET.SenderMAC] ;Our MAC-addr
movsd
movsw
mov esi,[SenderIP_ptr]
lea edi,[esp + ARP_PACKET.SenderIP] ;Our IP-addr
movsd
xor eax, eax
lea edi, [esp + ARP_PACKET.TargetMAC] ;Required MAC-addr(zeroed)
stosd
stosw
mov esi, dword[TargetIP]
mov dword[esp + ARP_PACKET.TargetIP],esi ;Required IP-addr(we get it as function parameter)
; Now, send it!
mov edi, broadcast_add ; Pointer to 48 bit destination address
mov bx, ETHER_ARP ; Type of packet
mov ecx, 28 ; size of packet
lea esi, [esp + ARP_PACKET]; pointer to packet data
call dword [drvr_transmit] ; Call the drivers transmit function
add esp, 28 ; free memory, allocated before for ARP_PACKET
; Add an entry in the ARP table, awaiting response
sub esp, ARP_ENTRY_SIZE ;allocate memory for ARP-entry
mov esi, dword[TargetIP]
mov dword[esp + ARP_ENTRY.IP],esi
lea edi, [esp + ARP_ENTRY.MAC]
xor eax, eax
stosd
stosw
mov word[esp + ARP_ENTRY.Status], ARP_AWAITING_RESPONSE
mov word[esp + ARP_ENTRY.TTL], 0x000A ; 10 seconds
stdcall arp_table_manager,ARP_TABLE_ADD,EXTRA_IS_ARP_ENTRY_PTR,esp
add esp, ARP_ENTRY_SIZE ; free memory
.exit:
ret
endp