kolibrios/kernel/trunk/network/udp.inc

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$Revision$
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2007. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2007. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;; ;;
;; UDP.INC ;;
;; ;;
;; UDP Processes for Menuet OS TCP/IP stack ;;
;; ;;
;; Version 0.3 29 August 2002 ;;
;; ;;
;; Copyright 2002 Mike Hibbett, mikeh@oceanfree.net ;;
;; ;;
;; See file COPYING for details ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;*******************************************************************
; 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
;
;***************************************************************************
udp_rx:
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
movzx ebx, word [edx + 22] ; get the local port from
; the IP packet's UDP header
mov eax, SOCKETBUFFSIZE * NUM_SOCKETS
mov ecx, NUM_SOCKETS
fs1:
sub eax, SOCKETBUFFSIZE
cmp [eax + sockets + 12], bx ; bx will hold the 'wrong' value,
; but the comparision is correct
loopnz fs1 ; Return back if no match
jz fs_done
; No match, so exit
jmp udprx_001
fs_done:
; 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
mov ebx, [eax + sockets + 16]
cmp ebx, 0xffffffff
je udprx_002
mov ebx, [edx + 12] ; get the Source address from the IP packet
cmp [eax + sockets + 16], ebx
jne udprx_001 ; Quit if the source IP is not valid
udprx_002:
; 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
movzx ebx, word [edx + 20] ; get the UDP source port
; ( was 69, now new )
mov [eax + sockets + 20], bx
; 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, byte [edx + 3] ; total length of IP packet. Subtract
mov ch, byte [edx + 2] ; 20 + 8 gives data length
sub ecx, 28
mov ebx, eax
add ebx, sockets ; ebx = address of actual socket
mov eax, [ebx+ 4] ; get socket owner PID
push eax
mov eax, [ebx + 24] ; get # of bytes already in buffer
add [ebx + 24], ecx ; increment the count of bytes in buffer
; point to the location to store the data
add ebx, eax
add ebx, SOCKETHEADERSIZE
; ebx = location for first byte, ecx has count,
; edx points to data
add edx, 28 ; edx now points to the data
mov edi, ebx
mov esi, edx
cld
rep movsb ; copy the data across
; flag an event to the application
pop eax
mov ecx,1
mov esi,TASK_DATA+TASKDATA.pid
newsearch:
cmp [esi],eax
je foundPID
inc ecx
add esi,0x20
cmp ecx,[TASK_COUNT]
jbe newsearch
foundPID:
shl ecx,8
or dword [ecx+SLOT_BASE+APPDATA.event_mask],dword 10000000b ; stack event
mov [check_idle_semaphore],200
udprx_001:
pop eax
call freeBuff ; Discard the packet
ret