test    eax,eax
    jnz     not0
    ; Read the configuartion word
    mov     eax, [stack_config]
    ret
   
not0:
    cmp     eax, 1
    jnz     not1
    ; read the IP address
   
    mov     eax, [stack_ip]
    ret
   
not1:
    cmp     eax, 2
    jnz     not2
   
    ; write the configuration word
    mov     [stack_config], ebx
   
    ; <Slip shouldn't be active anyway - thats an operational issue.>
    ; If ethernet now enabled, probe for the card, reset it and empty
    ; the packet buffer
    ; If all successfull, enable the card.
    ; If ethernet now disabled, set it as disabled. Should really
    ; empty the tcpip data area too.
   
    ; ethernet interface is '3' in ls 7 bits
    and     bl, 0x7f
    cmp     bl, 3
   
    je       ash_eth_enable
    ; Ethernet isn't enabled, so make sure that the card is disabled
    mov     [ethernet_active], byte 0
    
    ret
   
ash_eth_enable:
    ; Probe for the card. This will reset it and enable the interface
    ; if found
    call    eth_probe
    test    eax,eax
    je      ash_eth_done            ; Abort if no hardware found
   
    mov     [ethernet_active], byte 1
   
ash_eth_done:   
    ret
   
not2:
    cmp     eax, 3
    jnz     not3
    ; write the IP Address
    mov     [stack_ip], ebx
    ret
   
not3:
    cmp     eax, 4
    jnz     not4
    ; Enabled the slip driver on the comm port
if SLIP_PRESENT = TRUE
    call    enable_slip
end if
    ret
   
not4:
    cmp     eax, 5
    jnz     stack_driver_end
    ; Disable the slip driver on the comm port
if SLIP_PRESENT = TRUE
    call    disable_slip
end if   

stack_driver_end:
    ret
   
   
   
;***************************************************************************
;   Function
;      app_socket_handler
;
;   Description
;       This is an application service, called by int 0x40
;       It provides application access to stack socket services
;       such as opening sockets
;
;***************************************************************************
app_socket_handler:
    test    eax,eax
    jnz     nots0
   
    call    socket_open
    ret
   
nots0:
    cmp     eax, 1
    jnz     nots1
   
    call    socket_close
    ret
   
nots1:
    cmp     eax, 2
    jnz     nots2
   
    call    socket_poll
    ret
   
nots2:
    cmp     eax, 3
    jnz     nots3
   
    call    socket_read
    ret
   
nots3:
    cmp     eax, 4
    jnz     nots4
   
    call    socket_write
    ret
   
nots4:
    cmp     eax, 5
    jnz     nots5

    call    socket_open_tcp
    ret

nots5:
    cmp     eax, 6
    jnz     nots6
   
    call    socket_status
    ret

nots6:
    cmp     eax, 7
    jnz     nots7
   
    call    socket_write_tcp
    ret

nots7:
    cmp     eax, 8
    jnz     nots8
    
    call    socket_close_tcp
    ret
    
nots8:
    cmp     eax, 9
    jnz     nots9
    
    call    is_localport_unused
    ret
    
nots9:
    cmp     eax, 254
    jnz     notdump
   
    ret
   
notdump:
    cmp     eax, 255
    jnz     notsdebug
   
    ; This sub function allows access to debugging information on the stack
    ; ebx holds the request:
    ;  100 : return length of empty queue
    ;  101 : return length of IPOUT QUEUE
    ;  102 : return length of IPIN QUEUE
    ;  103 : return length of NET1OUT QUEUE
    ; 200 : return # of ARP entries
    ; 201 : return size of ARP table ( max # entries )
    ; 202 : select ARP table entry #
    ; 203 : return IP of selected table entry
    ; 204 : return High 4 bytes of MAC address of selected table entry
    ; 205 : return low  2 bytes of MAC address of selected table entry
    ; 206 : return status word of selected table entry
    ; 207 : return Time to live of selected table entry
    

    ;  2 : return number of IP packets received
    ;  3 : return number of packets transmitted
    ;  4 : return number of received packets dumped
    ;  5 : return number of arp packets received
    ;  6 : return status of packet driver
    ;      ( 0 == not active, FFFFFFFF = successful )
   
    call    stack_internal_status
    ret
   
notsdebug:
    ; Invalid Option
    ret
   

ARPTmp:    
times 14 db 0
   
;***************************************************************************
;   Function
;      stack_internal_status
;
;   Description
;       Returns information about the internal status of the stack
;       This is only useful for debugging
;       It works with the ethernet driver
;       sub function in ebx
;       return requested data in eax
;
;***************************************************************************
stack_internal_status:
    cmp     ebx, 100
    jnz     notsis100
   
    ;  100 : return length of EMPTY QUEUE
    mov     ebx, EMPTY_QUEUE
    call    queueSize   
    ret
   
notsis100:
    cmp     ebx, 101
    jnz     notsis101
   
    ;  101 : return length of IPOUT QUEUE
    mov     ebx, IPOUT_QUEUE
    call    queueSize   
    ret
   
notsis101:
    cmp     ebx, 102
    jnz     notsis102
   
    ;  102 : return length of IPIN QUEUE
    mov     ebx, IPIN_QUEUE
    call    queueSize   
    ret

notsis102:
    cmp     ebx, 103
    jnz     notsis103
   
    ;  103 : return length of NET1OUT QUEUE
    mov     ebx, NET1OUT_QUEUE
    call    queueSize   
    ret

notsis103:
    cmp     ebx, 200
    jnz     notsis200
    
    ; 200 : return num entries in arp table
    movzx   eax, byte [NumARP]
    ret
    
notsis200:
    cmp     ebx, 201
    jnz     notsis201
    
    ; 201 : return arp table size
    mov     eax, 20 ; ARP_TABLE_SIZE
    ret

notsis201:
    cmp     ebx, 202
    jnz     notsis202

    ; 202 - read the requested table entry 
    ; into a temporary buffer
    ; ecx holds the entry number
    
    mov     eax, ecx
    mov     ecx, 14 ; ARP_ENTRY_SIZE
    mul     ecx
    
    mov     ecx, [eax + ARPTable]
    mov     [ARPTmp], ecx
    mov     ecx, [eax + ARPTable+4]
    mov     [ARPTmp+4], ecx
    mov     ecx, [eax + ARPTable+8]
    mov     [ARPTmp+8], ecx
    mov     cx, [eax + ARPTable+12]
    mov     [ARPTmp+12], cx
    ret
        
notsis202:    
    cmp     ebx, 203
    jnz     notsis203

    ; 203 - return IP address
    mov     eax, [ARPTmp]
    ret
    
notsis203:
    cmp     ebx, 204
    jnz     notsis204

    ; 204 - return MAC high dword
    mov     eax, [ARPTmp+4]
    ret
    
notsis204:
    cmp     ebx, 205
    jnz     notsis205

    ; 205 - return MAC ls word
    movzx   eax, word [ARPTmp+8]
    ret
    
notsis205:
    cmp     ebx, 206
    jnz     notsis206

    ; 206 - return status word
    movzx   eax, word [ARPTmp+10]
    ret
    
notsis206:
    cmp     ebx, 207
    jnz     notsis207

    ; 207 - return ttl word
    movzx   eax, word [ARPTmp+12]
    ret
    
notsis207:
    cmp     ebx, 2
    jnz     notsis2
   
    ;  2 : return number of IP packets received
    mov     eax, [ip_rx_count]
    ret
   
notsis2:
    cmp     ebx, 3
    jnz     notsis3
   
    ;  3 : return number of packets transmitted
    mov     eax, [ip_tx_count]
    ret
   
notsis3:
    cmp     ebx, 4
    jnz     notsis4
   
    ;  4 : return number of received packets dumped
    mov     eax, [dumped_rx_count]
    ret
   
notsis4:
    cmp     ebx, 5
    jnz     notsis5
   
    ;  5 : return number of arp packets received
    mov     eax, [arp_rx_count]
    ret
   
notsis5:
    cmp     ebx, 6
    jnz     notsis6
   
    ;  6 : return status of packet driver
    ;  ( 0 == not active, FFFFFFFF = successful )
    mov     eax, [eth_status]
    ret
   
notsis6:
    xor     eax, eax
    ret
   
   
   
;***************************************************************************
;   Function
;      socket_open
;
;   Description
;       find a free socket
;       local port in ebx
;       remote port in ecx
;       remote ip in edx
;       return socket # in eax, -1 if none available
;
;***************************************************************************
socket_open:
    call    get_free_socket
   
    cmp     eax, 0xFFFFFFFF
    jz      so_exit
   
    ; ax holds the socket number that is free. Get real address
    push    eax
    shl     eax, 12
    add     eax, sockets
   
    mov     [eax], dword SOCK_OPEN
   
    mov     [eax + 12], byte bh      ; Local port ( LS 16 bits )
    mov     [eax + 13], byte bl      ; Local port ( LS 16 bits )
    mov     ebx, [stack_ip]
    mov     [eax + 8], ebx         ; Local IP
    mov     [eax + 20], ch         ; Remote Port ( LS 16 bits )
    mov     [eax + 21], cl         ; Remote Port ( LS 16 bits )
    mov     [eax + 16], edx         ; Remote IP ( in Internet order )
    mov     [eax + 24], dword 0      ; recieved data count
   
    mov     esi, [0x3010]
    mov     ebx, [esi+0x4]
    mov     [eax + 4], ebx         ; save the process ID
    pop     eax      ; Get the socket number back, so we can return it
   
so_exit:
    ret
   


;***************************************************************************
;   Function
;      socket_open_tcp
;
;   Description
;       Opens a TCP socket in PASSIVE or ACTIVE mode
;       find a free socket
;       local port in ebx ( intel format )
;       remote port in ecx ( intel format )
;       remote ip in edx ( in Internet byte order )
;       Socket open mode in esi  ( SOCKET_PASSIVE or SOCKET_ACTIVE )
;       return socket # in eax, -1 if none available
;
;***************************************************************************
socket_open_tcp:
    call    get_free_socket
   
    cmp     eax, 0xFFFFFFFF
    jz      so_exit
   
    ; ax holds the socket number that is free. Get real address
    push    eax
    shl     eax, 12
    add     eax, sockets

    mov     [sktAddr], eax
    mov     [eax], dword SOCK_OPEN
   
    mov     [eax + 12], byte bh      ; Local port ( LS 16 bits )
    mov     [eax + 13], byte bl      ; Local port ( LS 16 bits )
    mov     ebx, [stack_ip]
    mov     [eax + 8], ebx         ; Local IP
    mov     [eax + 20], ch         ; Remote Port ( LS 16 bits )
    mov     [eax + 21], cl         ; Remote Port ( LS 16 bits )
    mov     [eax + 16], edx         ; Remote IP ( in Internet order )
    mov     [eax + 24], dword 0      ; recieved data count
   
    ; Now fill in TCB state
    mov     ebx, TCB_LISTEN
    cmp     esi, SOCKET_PASSIVE
    jz      sot_001
    mov     ebx, TCB_SYN_SENT

sot_001:
    mov     [eax + 28], ebx            ; Indicate the state of the TCB

    mov     esi, [0x3010]
    mov     ecx, [esi+0x4]
    mov     [eax + 4], ecx         ; save the process ID
      
    cmp     ebx, TCB_LISTEN
    je      sot_done    
    
    ; Now, if we are in active mode, then we have to send a SYN to the specified remote port
   
  
    mov     eax, EMPTY_QUEUE
    call    dequeue
    cmp     ax, NO_BUFFER
    je      sot_done
   
    push    eax
    
    mov     bl, 0x02        ; SYN
    mov     ecx, 0
    
    call    buildTCPPacket    
    
    mov     eax, NET1OUT_QUEUE

    mov     edx, [stack_ip]
    mov     ecx, [ sktAddr ]
    mov     ecx, [ ecx + 16 ]
    cmp     edx, ecx
    jne     sot_notlocal