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}

; The function 'resolve' resolves the address in edx and puts the resulting IP in eax.

; When the input is an IP-adress, the function will output this IP in eax.

; If something goes wrong, the result in eax should be 0

;

; example:

;

; resolve query1,IP,PORT

; resolve '192.168.0.1',IP,PORT

; resolve query2,IP,PORT

;

; query1 db 'www.google.com',0

; query2 db '49.78.84.45',0

; IP     dd ?

; PORT   dd ?

macro resolve query,result {

if    query eqtype 0

 mov   edx,query

else

 local ..string, ..label

 jmp   ..label

 ..string db query,0

 ..label:

 mov   edx,..string

end   if

call  __resolve

mov   result,eax

__resolve:

if __DEBUG__ eq 1

DEBUGF 1,'DNS: Resolving started\n'

    bswap   edx 	      ; we want little endian order

no_IP:

    pop     edx

    ; The query is not an IP address, we will send the query to a DNS server and hope for answer ;)

if __DEBUG__ eq 1

    DEBUGF 1,'DNS: The query is no ip, Building request string from:%u\n',edx

end if

    ; Build the request string

    mov     eax, 0x00010100

    mov     [dnsMsg], eax

    mov     eax, 0x00000100

    mov     [dnsMsg+4], eax

    mov     eax, 0x00000000

    mov     [dnsMsg+8], eax

    ; domain name goes in at dnsMsg+12

    mov     esi, dnsMsg + 12			 ; location of label length

    mov     edi, dnsMsg + 13			 ; label start

    mov     ecx, 12				 ; total string length so far

td002:

    mov     [esi], byte 0

    inc     ecx

td0021:

    mov     al, [edx]

    cmp     al, 0

    je	    td001				 ; we have finished the string translation

    cmp     al, '.'

    je	    td004				 ; we have finished the label

    inc     byte [esi]

    inc     ecx

    mov     [edi], al

    inc     edi

    inc     edx

    jmp     td0021

td004:

    mov     esi, edi

    inc     edi

    inc     edx

    jmp     td002

    ; write label len + label text

td001:

    mov     [edi], byte 0

    inc     ecx

    inc     edi

    mov     [edi], dword 0x01000100

    add     ecx, 4

    mov     [dnsMsgLen], ecx			 ; We'll need the length of the message when we send it

    ; Now, lets send this and wait for an answer

    eth.search_port 1024,edx			 ; Find a free port starting from 1025 and store in edx

    eth.get_DNS esi				 ; Read DNS IP from stack into esi

    eth.open_udp edx,53,esi,[socketNum] 	     ; First, open socket

if __DEBUG__ eq 1

    DEBUGF 1,'DNS: Socket opened: %u (port %u)\n',[socketNum],ecx

end if

    eth.write_udp [socketNum],[dnsMsgLen],dnsMsg     ; Write to socket ( request DNS lookup )

if __DEBUG__ eq 1

    DEBUGF 1,'DNS: Data written, length:%u offset:%u\n',[dnsMsgLen],dnsMsg

    DEBUGF 1,'DNS: Waiting for data: (timeout is %us)\n',TIMEOUT

end if

    eth.wait_for_data [socketNum],TIMEOUT,abort  ; Now, we wait for data from remote

    eth.read_data dword[socketNum],dnsMsg,dword[dnsMsgLen],dnsMsg+BUFFER      ; Read the data into the buffer

if __DEBUG__ eq 1

    DEBUGF 1,'Data received, offset:%u buffer size:%u length:%u\n',dnsMsg,BUFFER,esi-dnsMsg

end if

    eth.close_udp [socketNum]			     ; We're done, close the socket

if __DEBUG__ eq 1

    DEBUGF 1,'Closed Socket\n'

end if

    ; Now parse the message to get the host IP. Man, this is complicated. It's described in RFC 1035

    ; 1) Validate that we have an answer with > 0 responses

    ; 2) Find the answer record with TYPE 0001 ( host IP )

    ; 3) Finally, copy the IP address to the display

    ; Note: The response is in dnsMsg, the end of the buffer is pointed to by [dnsMsgLen]

    mov     esi, dnsMsg

    mov     al, [esi+2] 			 ; Is this a response to my question?

    and     al, 0x80

    cmp     al, 0x80

    jne     abort

if __DEBUG__ eq 1

    DEBUGF 1,'DNS: It was a response to my question\n'

end if

    mov     al, [esi+3] 			 ; Were there any errors?

    and     al, 0x0F

    cmp     al, 0x00

    jne     abort

if __DEBUG__ eq 1

    DEBUGF 1,'DNS: There were no errors\n'

end if

    mov     ax, [esi+6] 			 ; Is there ( at least 1 ) answer?

    cmp     ax, 0x00

    je	    abort

    ; Header validated. Scan through and get my answer

    add     esi, 12				 ; Skip to the question field

    call    skipName				 ; Skip through the question field

    add     esi, 4				 ; skip past the questions qtype, qclass

ctr002z:

    ; Now at the answer. There may be several answers, find the right one ( TYPE = 0x0001 )

    call    skipName

    mov     ax, [esi]

    cmp     ax, 0x0100				 ; Is this the IP address answer?

    jne     ctr002c

    add     esi, 10				 ; Yes! Point eax to the first byte of the IP address

    mov     eax,[esi]

    ret

ctr002c:					 ; Skip through the answer, move to the next

    add     esi, 8

    movzx   eax, byte [esi+1]

    mov     ah, [esi]

    add     esi, eax

    add     esi, 2

    cmp     esi, [dnsMsgLen]			 ; Have we reached the end of the msg? This is an error condition, should not happen

    jl	    ctr002z				 ; Check next answer

abort:

if __DEBUG__ eq 1

    DEBUGF 1,'DNS: Something went wrong, aborting\n'

end if

    xor     eax,eax

    ret

skipName:

    ; Increment esi to the first byte past the name field

    ; Names may use compressed labels. Normally do.

    ; RFC 1035 page 30 gives details

    mov     al, [esi]

    cmp     al, 0

    je	    sn_exit

    and     al, 0xc0

    cmp     al, 0xc0

    je	    sn001

    movzx   eax, byte [esi]

    inc     eax

    add     esi, eax

    jmp     skipName

sn001:

    add     esi, 2				 ; A pointer is always at the end

sn_exit:

    inc     esi

    ret

dnsMsgLen:	dd 0

socketNum:	dd 0xFFFF

if ~defined dnsMsg