kolibrios/kernel/trunk/network/ip.inc

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;                                                                 ;;
;; Copyright (C) KolibriOS team 2004-2011. All rights reserved.    ;;
;; Distributed under terms of the GNU General Public License       ;;
;;                                                                 ;;
;;                                                                 ;;
;;  IP.INC                                                         ;;
;;                                                                 ;;
;;  IP 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                                   ;;
;;                                                                 ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

$Revision$


; IP underlying protocols numbers
PROTOCOL_ICMP     equ      1
PROTOCOL_TCP      equ      6
PROTOCOL_UDP      equ      17

struc IP_PACKET
{  .VersionAndIHL           db   ?  ;+00 - Version[0-3 bits] and IHL(header length)[4-7 bits]
   .TypeOfService           db   ?  ;+01
   .TotalLength             dw   ?  ;+02
   .Identification          dw   ?  ;+04
   .FlagsAndFragmentOffset  dw   ?  ;+06 - Flags[0-2] and FragmentOffset[3-15]
   .TimeToLive              db   ?  ;+08
   .Protocol                db   ?  ;+09
   .HeaderChecksum          dw   ?  ;+10
   .SourceAddress           dd   ?  ;+12
   .DestinationAddress      dd   ?  ;+16
   .DataOrOptional          dd   ?  ;+20
}

virtual at 0
  IP_PACKET IP_PACKET
end virtual


;*******************************************************************
;   Interface
;
;       ip_rx       processes all packets received by the network layer
;                   It calls the appropriate protocol handler
;
;
;
;*******************************************************************


;
;   IP Packet after reception - Normal IP packet format
;
;           0               1               2               3
;    0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
;
;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;0  |Version|  IHL  |Type of Service|       Total Length            |
;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;4  |         Identification        |Flags|      Fragment Offset    |
;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;8  |  Time to Live |    Protocol   |         Header Checksum       |
;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;12 |                       Source Address                          |
;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;16 |                    Destination Address                        |
;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
;20 |      Data                                                     |
;   +-+-+-..........                                               -+
;
;
;    [smb] attention! according to RFC 791 IP packet may have 'options' sections,
; so we can't simply think, that data have offset 20. We must calculate offset from
; IHL field
;
macro   GET_IHL reg, header_addr
{
        movzx   reg, byte [header_addr]
        
        ; we need 4-7 bits, so....
        and     reg, 0x0000000F
        
        ; IHL keeps number of octets, so we need to << 2 'reg'
        shl     reg, 2
}


include "tcp.inc"
include "udp.inc"
include "icmp.inc"

;***************************************************************************
;   Function
;      ip_rx
;
;   Description
;       This is a kernel function, called by stack_handler
;       Processes all IP-packets received by the network layer
;       It calls the appropriate protocol handler
;
;***************************************************************************
proc ip_rx stdcall
local buffer_number dd ?

    ; Look for a buffer to tx
        mov     eax, IPIN_QUEUE
        call    dequeue
        cmp     ax, NO_BUFFER
        je      .exit     ; Exit if no buffer available

        mov     [buffer_number], eax;save buffer number

    ; convert buffer pointer eax to the absolute address
        imul    eax, IPBUFFSIZE
        add     eax, IPbuffs

        mov     ebx, eax; ebx=pointer to IP_PACKET

;        DEBUGF  1, "K : ip_rx - proto: %u\n", [ebx + IP_PACKET.Protocol]:1

    ; Validate the IP checksum
        mov     dx, word[ebx + IP_PACKET.HeaderChecksum]
        xchg    dh, dl     ; Get the checksum in intel format
  
        mov     [ebx + IP_PACKET.HeaderChecksum], 0; clear checksum field - need to when
                                ; recalculating checksum
    ;  this needs two data pointers and two size #.
    ;  2nd pointer can be of length 0

    GET_IHL ecx, ebx + IP_PACKET.VersionAndIHL ;get packet length in ecx
        stdcall checksum_jb, ebx, ecx;buf_ptr, buf_size
        cmp     dx, ax

;        DEBUGF  1, "K : ip_rx - checksums: %x - %x\n", dx, ax

        jnz     .dump.1;if CHECKSUM isn't valid then dump packet
        mov     edx, ebx; EDX (IP-BUFFER POINTER) WILL BE USED FOR *_rx HANDLERS BELOW!!!

;        DEBUGF  1, "K : ip_rx - dest: %x - %x\n", [ebx + IP_PACKET.DestinationAddress], [stack_ip]

    ; Validate the IP address, if it isn't broadcast
        mov     eax, [stack_ip]
        cmp     dword[ebx + IP_PACKET.DestinationAddress], eax
        je      @f

    ; If the IP address is 255.255.255.255, accept it
    ; - it is a broadcast packet, which we need for dhcp

        mov     eax, [ebx + IP_PACKET.DestinationAddress]
        cmp     eax, 0xffffffff
        je      @f
        mov     ecx, [stack_ip]
        and     eax, [subnet_mask]
        and     ecx, [subnet_mask]
        cmp     eax, ecx
        jne     .dump.2
        mov     eax, [ebx + IP_PACKET.DestinationAddress]
        or      eax, [subnet_mask]
        cmp     eax, 0xffffffff
        jne     .dump.2

  @@:
        mov     al, [ebx + IP_PACKET.VersionAndIHL]
        and     al, 0x0f;get IHL(header length)
        cmp     al, 0x05;if IHL!= 5*4(20 bytes)
;        DEBUGF  1, "K : ip_rx - ihl: %x - 05\n", al
        jnz     .dump.3 ;then dump it

;        DEBUGF  1, "K : ip_rx - ttl: %x - 00\n", [ebx + IP_PACKET.TimeToLive]:2

        cmp     [ebx + IP_PACKET.TimeToLive], 0
        je      .dump.4 ;if TTL==0 then dump it

        mov     ax, [ebx + IP_PACKET.FlagsAndFragmentOffset]
        and     ax, 0xFFBF;get flags
;        DEBUGF  1, "K : ip_rx - flags: %x - 0000\n", ax
        cmp     ax, 0    ;if some flags was set then we dump this packet
        jnz     .dump.5    ;the flags should be used for fragmented packets

    ; Check the protocol, and call the appropriate handler
    ; Each handler will re-use or free the queue buffer as appropriate

        mov     al, [ebx + IP_PACKET.Protocol]

        cmp     al , PROTOCOL_TCP
        jne     .not_tcp
;    DEBUGF  1,"K : ip_rx - TCP packet\n"
        mov     eax, dword[buffer_number]
        call    tcp_rx
        jmp     .exit

  .not_tcp:
        cmp     al, PROTOCOL_UDP
        jne     .not_udp
;    DEBUGF  1,"K : ip_rx - UDP packet\n"
        mov     eax, dword[buffer_number]
        call    udp_rx
        jmp     .exit

  .not_udp:
        cmp     al, PROTOCOL_ICMP
        jne     .dump.6          ;protocol ain't supported

;    DEBUGF  1,"K : ip_rx - ICMP packet\n"
    ;GET_IHL ecx, ebx + IP_PACKET.VersionAndIHL ;get packet length in ecx
        mov     eax, dword[buffer_number]
        stdcall icmp_rx, eax, ebx, ecx;buffer_number,IPPacketBase,IPHeaderLength
        jmp     .exit


  .dump.1:
;        DEBUGF  1, "K : ip_rx - dumped (checksum: 0x%x-0x%x)\n", dx, ax
        jmp     .dump.x

  .dump.2:
;        DEBUGF  1, "K : ip_rx - dumped (ip: %u.%u.%u.%u)\n", [ebx + IP_PACKET.DestinationAddress + 0]:1, [ebx + IP_PACKET.DestinationAddress + 1]:1, [ebx + IP_PACKET.DestinationAddress + 2]:1, [ebx + IP_PACKET.DestinationAddress + 3]:1
        jmp     .dump.x

  .dump.3:
;        DEBUGF  1, "K : ip_rx - dumped (ihl: %u)\n", al
        jmp     .dump.x

  .dump.4:
;        DEBUGF  1, "K : ip_rx - dumped (ttl: %u)\n", [ebx + IP_PACKET.TimeToLive]
        jmp     .dump.x

  .dump.5:
;        DEBUGF  1, "K : ip_rx - dumped (flags: 0x%x)\n", ax
        jmp     .dump.x

  .dump.6:
;        DEBUGF  1, "K : ip_rx - dumped (proto: %u)\n", [ebx + IP_PACKET.Protocol]:1

  .dump.x:
        inc     dword[dumped_rx_count]
        mov     eax, [buffer_number]
        call    freeBuff

  .exit:
        ret
endp