Subversion Repositories Kolibri OS

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;;                                                              ;;

;; Copyright (C) KolibriOS team 2004-2008. All rights reserved. ;;

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

;;                                                              ;;

;;                                                              ;;

;;  UDP.INC                                                     ;;

;;                                                              ;;

;;  UDP Processes for Menuet OS  TCP/IP stack                   ;;

;;                                                              ;;

;;  Copyright 2002 Mike Hibbett, mikeh@oceanfree.net            ;;

;;                                                              ;;

;;  See file COPYING for details                                ;;

;;                                                              ;;

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

$Revision: 2971 $

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

;   Interface

;

;       udp_rx      Handles received IP packets with the UDP protocol

;

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

;

;   UDP Payload ( Data field in IP datagram )

;

;    0                   1                   2                   3

;    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

;

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;   |       Source Port             |      Destination Port         |

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;   | Length ( UDP Header + Data )  |           Checksum            |

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;   |       UDP Data                                                |

;   +-+-+-..........                                               -+

;

struc UDP_PACKET

{  .SourcePort       dw  ?  ;+00

   .DestinationPort  dw  ?  ;+02

   .Length           dw  ?  ;+04 - Length of (UDP Header + Data)

   .Checksum         dw  ?  ;+06

   .Data             db  ?  ;+08

}

virtual at 0

  UDP_PACKET UDP_PACKET

end virtual

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

;   Function

;      udp_rx  [by Johnny_B]

;

;   Description

;       UDP protocol handler

;       This is a kernel function, called by ip_rx

;       IP buffer address given in edx

;          IP buffer number in eax

;          Free up (or re-use) IP buffer when finished

;

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

proc udp_rx stdcall

    push    eax

    ; First validate the header & checksum. Discard buffer if error

    ; Look for a socket where

    ; IP Packet UDP Destination Port = local Port

    ; IP Packet SA = Remote IP

	mov	ax, [edx + 20 + UDP_PACKET.DestinationPort]   ; get the local port from

                                  ; the IP packet's UDP header

	mov	ebx, net_sockets

  .next_socket:

	mov	ebx, [ebx + SOCKET.NextPtr]

	or	ebx, ebx

	jz	.exit					; No match, so exit

	cmp	[ebx + SOCKET.LocalPort], ax		; ax will hold the 'wrong' value,

                                    ; but the comparision is correct

	jne	.next_socket				; Return back if no match

    ; For dhcp, we must allow any remote server to respond.

    ; I will accept the first incoming response to be the one

    ; I bind to, if the socket is opened with a destination IP address of

    ; 255.255.255.255

	cmp	[ebx + SOCKET.RemoteIP], 0xffffffff

	je	@f

	mov	eax, [edx + IP_PACKET.SourceAddress]	; get the Source address from the IP packet

	cmp	[ebx + SOCKET.RemoteIP], eax

	jne	.exit		   ; Quit if the source IP is not valid

    @@: ; OK - we have a valid UDP packet for this socket.

    ; First, update the sockets remote port number with the incoming msg

    ; - it will have changed

    ; from the original ( 69 normally ) to allow further connects

	mov	ax, [edx + 20 + UDP_PACKET.SourcePort]		; get the UDP source port

                                     ; ( was 69, now new )

	mov	[ebx + SOCKET.RemotePort], ax

    ; Now, copy data to socket. We have socket address as [eax + sockets].

    ; We have IP packet in edx

    ; get # of bytes in ecx

	movzx	ecx, [edx + IP_PACKET.TotalLength]	; total length of IP packet. Subtract

	xchg	cl, ch					; 20 + 8 gives data length

    sub     ecx, 28

	mov	eax, [ebx + SOCKET.rxDataCount] 	; get # of bytes already in buffer

	add	[ebx + SOCKET.rxDataCount], ecx 	; increment the count of bytes in buffer

	; ecx has count, edx points to data

    add     edx, 28        ; edx now points to the data

	lea	edi, [ebx + eax + SOCKETHEADERSIZE]

    mov     esi, edx

    cld

    rep     movsb          ; copy the data across

    ; flag an event to the application

	mov	eax, [ebx + SOCKET.PID] 		; get socket owner PID

	mov	ecx, 1

	mov	esi, TASK_DATA + TASKDATA.pid

  .next_pid:

	cmp	[esi], eax

	je	.found_pid

    inc     ecx

	add	esi, 0x20

	cmp	ecx, [TASK_COUNT]

	jbe	.next_pid

	jmp	.exit

  .found_pid:

	shl	ecx, 8

	or	[ecx + SLOT_BASE + APPDATA.event_mask], EVENT_NETWORK ; stack event

	mov	[check_idle_semaphore], 200

  .exit:

    pop     eax

    call    freeBuff    ; Discard the packet

    ret

endp