WebSVN – Kolibri OS – Diff – /kernel/branches/gfx_kernel/network/ip.inc

 ;;                                                                 ;;
 ;;  See file COPYING for details                                   ;;
 ;;                                                                 ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; 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 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
+}
 ;***************************************************************************
 ;   Function
 ;      ip_rx
-;
 ;   Description
+;   Description
+;       This is a kernel function, called by stack_handler
-;       Handles received IP packets
+;       Processes all IP-packets received by the network layer
-;       This is a kernel function, called by stack_handler
+;       It calls the appropriate protocol handler
 ;
+;***************************************************************************
+proc ip_rx stdcall
-;***************************************************************************
+local buffer_number dd ?
 ip_rx:
     ; Look for a buffer to tx
     mov     eax, IPIN_QUEUE
     call    dequeue
     cmp     ax, NO_BUFFER
-    je      ipr_exit         ; Exit if no buffer available
+    je      .exit         ; Exit if no buffer available
-    push    eax
     mov     [buffer_number], eax    ;save buffer number
-    ; convert buffer pointer eax to the absolute address
-    mov     ecx, IPBUFFSIZE
+    ; convert buffer pointer eax to the absolute address
-    mul     ecx
-    add     eax, IPbuffs
+    imul    eax, IPBUFFSIZE
+    add     eax, IPbuffs
-    mov     edx, eax  ; Save the address in  edx for use by future processes
+    mov     ebx, eax  ; ebx=pointer to IP_PACKET
     ; Validate the IP checksum
-    mov     ebx, edx
+    ; Validate the IP checksum
-    mov     ah, [ebx + 10]
-    mov     al, [ebx + 11]      ; Get the checksum in intel format
-    mov     [ebx + 10], word 0  ; clear checksum field - need to when
-                                    ; recalculating checksum
-    ;  this needs two data pointers and two size #.
-    ;  2nd pointer can be of length 0
-    mov     ebx, edx
-    mov     [checkAdd1], ebx
-    mov     [checkSize1], word 20
+    mov     dx, word[ebx + IP_PACKET.HeaderChecksum]
-    mov     [checkAdd2], dword 0
+    xchg    dh,dl          ; Get the checksum in intel format
-    mov     [checkSize2], word 0
+    mov     [ebx + IP_PACKET.HeaderChecksum], word 0  ; clear checksum field - need to when
+                                ; recalculating checksum
-    call    checksum           ; Recalculate IP checksum
+    ;  this needs two data pointers and two size #.
-    cmp     ax, [checkResult]
+    ;  2nd pointer can be of length 0
-    jnz     ipr_dump
+    GET_IHL ecx, ebx + IP_PACKET.VersionAndIHL ;get packet length in ecx
+    stdcall checksum_jb, ebx, ecx   ;buf_ptr, buf_size
+    cmp     dx, ax
+    mov     edx, ebx ; EDX (IP-BUFFER POINTER) WILL BE USED FOR *_rx HANDLERS BELOW!!!
+    jnz     .dump  ;if CHECKSUM isn't valid then dump packet
-    ; If the IP address is 255.255.255.255, accept it
+    ; Validate the IP address, if it isn't broadcast
-    ; - it is a broadcast packet, which we need for dhcp
+    mov     eax, [stack_ip]
-    mov     eax, [edx + 16]
+    cmp     dword[ebx + IP_PACKET.DestinationAddress], eax
-    cmp     eax, 0xffffffff
+    je      @f
-    je      ipr_p0
+    ; If the IP address is 255.255.255.255, accept it
-    ; Validate the IP address, if it isn't broadcast
+    ; - it is a broadcast packet, which we need for dhcp
-    cmp     eax, [stack_ip]
+    cmp     dword[ebx + IP_PACKET.DestinationAddress], 0xffffffff
-    jnz     ipr_dump
+    jne     .dump
-ipr_p0:
+  @@:
-    mov     al, [edx]
+    mov     al, [ebx + IP_PACKET.VersionAndIHL]
-    and     al, 0x0f
+    and     al, 0x0f  ;get IHL(header length)
-    cmp     al, 0x05
+    cmp     al, 0x05  ;if IHL!= 5*4(20 bytes)
-    jnz     ipr_dump
+    jnz     .dump     ;then dump it
-    cmp     [edx+8], byte 0
-    jz      ipr_dump
-    mov     ax, [edx + 6]
-    and     ax, 0xFFBF
-    cmp     ax, 0
+    cmp     byte[ebx + IP_PACKET.TimeToLive], byte 0
-    jnz     ipr_dump
+    je      .dump     ;if TTL==0 then dump it
+    mov     ax, word[ebx + IP_PACKET.FlagsAndFragmentOffset]
-    ; Check the protocol, and call the appropriate handler
+    and     ax, 0xFFBF   ;get flags
-    ; Each handler will re-use or free the queue buffer as appropriate
+    cmp     ax, 0        ;if some flags was set then we dump this packet
-    mov     al, [edx + 9]
+    jnz     .dump        ;the flags should be used for fragmented packets
-    cmp     al , PROTOCOL_ICMP
-    jnz     ipr_p1
+    ; Check the protocol, and call the appropriate handler
-    pop     eax
+    ; Each handler will re-use or free the queue buffer as appropriate
-    call    icmp_rx
+    mov     al, [ebx + IP_PACKET.Protocol]
     jmp     ipr_exit
+    cmp     al , PROTOCOL_TCP
-ipr_p1:
+    jne     .not_tcp
-    cmp     al , PROTOCOL_TCP
+    DEBUGF  1,"K : ip_rx - TCP packet\n"
-    jnz     ipr_p2
+    mov     eax, dword[buffer_number]
-    pop     eax
-    call    tcp_rx
-    jmp     ipr_exit
+    call    tcp_rx
+    jmp     .exit
-ipr_p2:
-    cmp     al , PROTOCOL_UDP
+  .not_tcp:
-    jnz     ipr_dump
+    cmp     al, PROTOCOL_UDP
+    jne     .not_udp
+    DEBUGF  1,"K : ip_rx - UDP packet\n"
+    mov     eax, dword[buffer_number]
-    pop     eax
-    call    udp_rx
-    jmp     ipr_exit
-ipr_dump:
-    ; No protocol handler available, so
-    ; silently dump the packet, freeing up the queue buffer
-;    inc     dword [dumped_rx_count]
-    pop     eax
-    call    freeBuff
-ipr_exit:
+    call    udp_rx
+    jmp     .exit
     ret
-;***************************************************************************
-;   Function
-;      icmp_rx
-;
-;   Description
-;       ICMP protocol handler
-;       This is a kernel function, called by ip_rx
-;       edx contains the address of the buffer in use.
-;       This buffer must be reused or marked as empty afterwards
-;
-;***************************************************************************
-icmp_rx:
-    cmp     [edx + 20], byte 8 ; Is this an echo request? discard if not
-    jz      icmp_echo
-    call    freeBuff
-    jmp     icmp_exit
-icmp_echo:
-    push    eax
-    mov     [edx + 10], word 0  ; I think this was already done by IP rx
-    ; swap the source and destination addresses
-    mov     ecx, [edx + 16]
-    mov     eax, [edx + 12]
-    mov     [edx + 16], eax
-    mov     [edx + 12], ecx
-    ; recaluculate the IP header checksum
-    mov     ebx, edx
-    mov     [checkAdd1], ebx
-    mov     [checkSize1], word 20
-    mov     [checkAdd2], dword 0
-    mov     [checkSize2], word 0
-    call    checksum
-    mov     ax, [checkResult]
-    mov     [edx + 10], ah
-    mov     [edx + 11], al      ; ?? correct byte order?
-    mov     [edx + 20], byte 0  ; change the request to a response
-    mov     [edx + 22], word 0  ; clear ICMP checksum prior to re-calc
-    ; Calculate the length of the ICMP data ( IP payload)
-    mov     ah, [edx + 2]
-    mov     al, [edx + 3]
-    sub     ax, 20
-    mov     [checkSize1], ax
+  .not_udp:
-    mov     ebx, edx
+    cmp     al , PROTOCOL_ICMP
-    add     ebx, 20
+    jne     .dump              ;protocol ain't supported
+    DEBUGF  1,"K : ip_rx - ICMP packet\n"

Subversion Repositories Kolibri OS

(root)/kernel/branches/gfx_kernel/network/ip.inc – Rev 129 → 384