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;;                                                                 ;;

;; Copyright (C) KolibriOS team 2004-2017. All rights reserved.    ;;

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

;;                                                                 ;;

;;  Part of the TCP/IP network stack for KolibriOS                 ;;

;;                                                                 ;;

;;   Written by hidnplayr@kolibrios.org                            ;;

;;                                                                 ;;

;;    Based on the algorithms used in 4.4BSD                       ;;

;;                                                                 ;;

;;          GNU GENERAL PUBLIC LICENSE                             ;;

;;             Version 2, June 1991                                ;;

;;                                                                 ;;

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$Revision: 6915 $

TCP_BIT_NEEDOUTPUT      = 1 shl 0

TCP_BIT_TIMESTAMP       = 1 shl 1

TCP_BIT_DROPSOCKET      = 1 shl 2

TCP_BIT_FIN_IS_ACKED    = 1 shl 3

;-----------------------------------------------------------------;

;                                                                 ;

; TCP_input: Add a segment to the incoming TCP queue.             ;

;                                                                 ;

;  IN:  [esp] = ptr to buffer                                     ;

;       ebx = ptr to device struct                                ;

;       ecx = TCP segment size                                    ;

;       edx = ptr to IPv4 header                                  ;

;       esi = ptr to TCP segment                                  ;

;       edi = interface number*4                                  ;

;                                                                 ;

;  OUT: /                                                         ;

;                                                                 ;

;-----------------------------------------------------------------;

align 4

tcp_input:

; record the current time

        push    [timer_ticks]           ; in 1/100 seconds

        push    ebx ecx esi edx         ; mind the order (see TCP_queue_entry struct)

        mov     esi, esp

        push    edi

        add_to_queue TCP_queue, TCP_QUEUE_SIZE, sizeof.TCP_queue_entry, .fail

        pop     edi

        add     esp, sizeof.TCP_queue_entry

        inc     [TCP_segments_rx + edi]

        xor     edx, edx

        mov     eax, [TCP_input_event]

        mov     ebx, [eax + EVENT.id]

        xor     esi, esi

        call    raise_event

        ret

  .fail:

        pop     edi

        DEBUGF  DEBUG_NETWORK_VERBOSE, "TCP incoming queue is full, discarding packet!\n"

        call    net_ptr_to_num4

        inc     [TCP_segments_missed + edi]

        add     esp, sizeof.TCP_queue_entry - 4

        call    net_buff_free

        ret

;-----------------------------------------------------------------;

;                                                                 ;

; TCP_process_input: Process segments from the incoming TCP queue.;

;                                                                 ;

;  IN:  /                                                         ;

;  OUT: /                                                         ;

;                                                                 ;

;-----------------------------------------------------------------;

align 4

proc tcp_process_input

locals

        dataoffset      dd ?

        timestamp       dd ?

        temp_bits       db ?

        device          dd ?

endl

        xor     esi, esi

        mov     ecx, MANUAL_DESTROY

        call    create_event

        mov     [TCP_input_event], eax

  .wait:

        mov     eax, [TCP_input_event]

        mov     ebx, [eax + EVENT.id]

        call    wait_event

  .loop:

        get_from_queue TCP_queue, TCP_QUEUE_SIZE, sizeof.TCP_queue_entry, .wait

        push    [esi + TCP_queue_entry.timestamp]

        pop     [timestamp]

        push    [esi + TCP_queue_entry.buffer_ptr]

        mov     ebx, [esi + TCP_queue_entry.device_ptr]

        mov     [device], ebx

        mov     ecx, [esi + TCP_queue_entry.segment_size]

        mov     edi, [esi + TCP_queue_entry.ip_ptr]     ; ptr to ipv4 header

        mov     esi, [esi + TCP_queue_entry.segment_ptr]                ; change esi last

        DEBUGF  DEBUG_NETWORK_VERBOSE, "TCP_input: size=%u time=%d\n", ecx, [timer_ticks]

        mov     edx, esi

; Verify the checksum (if not already done by hw)

        test    [ebx + NET_DEVICE.hwacc], NET_HWACC_TCP_IPv4_IN

        jnz     .checksum_ok

        push    ecx esi

        pushw   [esi + TCP_header.Checksum]

        mov     [esi + TCP_header.Checksum], 0

        tcp_checksum (edi+IPv4_header.SourceAddress), (edi+IPv4_header.DestinationAddress)

        pop     cx                              ; previous checksum

        cmp     cx, dx

        pop     edx ecx

        jne     .drop_no_socket

  .checksum_ok:

; Verify the data offset

        movzx   eax, [edx + TCP_header.DataOffset]

        and     al, 0xf0                        ; Calculate TCP segment header size (throwing away unused reserved bits in TCP header)

        shr     al, 2

        cmp     al, sizeof.TCP_header           ; Now see if it's at least the size of a standard TCP header

        jb      .drop_no_socket                 ; If not, drop the packet

        mov     [dataoffset], eax

        sub     ecx, eax                                                ; substract TCP header size from total segment size

        jb      .drop_no_socket                                         ; If total segment size is less then the advertised header size, drop packet

        DEBUGF  DEBUG_NETWORK_VERBOSE, "TCP_input: %u bytes of data\n", ecx

;-------------------------------------------

; Convert Big-endian values to little endian

        ntohd   [edx + TCP_header.SequenceNumber]

        ntohd   [edx + TCP_header.AckNumber]

        ntohw   [edx + TCP_header.Window]

        ntohw   [edx + TCP_header.UrgentPointer]

;-----------------------------------------------------------------------------------

;

; Find the socket pointer

;

;-----------------------------------------------------------------------------------

; IP Packet TCP Destination Port = local Port

; (IP Packet SenderAddress = Remote IP)  OR  (Remote IP = 0)

; (IP Packet TCP Source Port = remote Port) OR (remote Port = 0)

  .findpcb:

        pusha

        mov     ecx, socket_mutex

        call    mutex_lock

        popa

        mov     ebx, net_sockets

        mov     si, [edx + TCP_header.DestinationPort]

  .socket_loop:

        mov     ebx, [ebx + SOCKET.NextPtr]

        or      ebx, ebx

        jz      .no_socket ;respond_seg_reset

        cmp     [ebx + SOCKET.Domain], AF_INET4

        jne     .socket_loop

        cmp     [ebx + SOCKET.Protocol], IP_PROTO_TCP

        jne     .socket_loop

        cmp     [ebx + TCP_SOCKET.LocalPort], si

        jne     .socket_loop

        mov     eax, [ebx + IP_SOCKET.RemoteIP]

        cmp     eax, [edi + IPv4_header.SourceAddress]

        je      @f

        test    eax, eax

        jnz     .socket_loop

       @@:

        mov     ax, [ebx + TCP_SOCKET.RemotePort]

        cmp     [edx + TCP_header.SourcePort], ax

        je      .found_socket

        test    ax, ax

        jnz     .socket_loop

  .found_socket:                                        ; ebx now contains the socketpointer