; ip65 main routines

.include "../inc/common.inc"
.include "../inc/error.inc"

.export ip65_init
.export ip65_process
.export ip65_random_word
.export ip65_ctr
.export ip65_ctr_arp
.export ip65_ctr_ip

.export ip65_error

.import eth_init
.import timer_init
.import arp_init
.import ip_init
.import timer_read

.import eth_inp
.import eth_outp
.import eth_rx

.import ip_process
.import arp_process

.importzp eth_proto_arp


.bss

ip65_ctr:       .res 1          ; incremented for every incoming packet
ip65_ctr_arp:   .res 1          ; incremented for every incoming arp packet
ip65_ctr_ip:    .res 1          ; incremented for every incoming ip packet

ip65_error:     .res 1          ; last error code


.code

; generate a 'random' 16 bit word
; entropy comes from the last ethernet frame, counters, and timer
; inputs: none
; outputs: AX set to a pseudo-random 16 bit number
ip65_random_word:
  jsr timer_read ;sets AX
  adc $4e                       ; on an Apple 2, this is RNDL
  adc $9004                     ; on a VIC 20, this is the raster register
  adc $d41b                     ; on a C64, this is a 'random' number from the SID
  adc $d20a                     ; on an Atari, this is a 'random' number from the POKEY
  pha
  adc ip65_ctr_arp
  ora #$08                      ; make sure we grab at least 8 bytes from eth_inp
  tax
: adc eth_inp,x
  adc eth_outp,x
  dex
  bne :-
  tax
  pla
  adc ip65_ctr
  eor ip65_ctr_ip
  rts

; initialise the IP stack
; this calls the individual protocol & driver initialisations, so this is
; the only *_init routine that must be called by a user application,
; except for dhcp_init which must also be called if the application
; is using dhcp rather than hardcoded ip configuration
; inputs: A = adaptor specific initialisation value or 'eth_init_default'
; outputs: carry flag is set if there was an error, clear otherwise
ip65_init:
  jsr eth_init                  ; initialize ethernet driver

  bcc @ok
  lda #IP65_ERROR_DEVICE_FAILURE
  sta ip65_error
  rts
@ok:
  jsr timer_init                ; initialize timer
  jsr arp_init                  ; initialize arp
  jsr ip_init                   ; initialize ip, icmp, udp, and tcp
  clc
  rts

; main ip polling loop
; this routine should be periodically called by an application at any time
; that an inbound packet needs to be handled.
; it is 'non-blocking', i.e. it will return if there is no packet waiting to be
; handled. any inbound packet will be handed off to the appropriate handler.
; inputs: none
; outputs: carry flag set if no packet was waiting, or packet handling caused error.
; since the inbound packet may trigger generation of an outbound, eth_outp
; and eth_outp_len may be overwriiten.
ip65_process:
  jsr eth_rx                    ; check for incoming packets
  bcs @done

  lda eth_inp + 12              ; type should be 08xx
  cmp #8
  bne @done

  lda eth_inp + 13
; cmp #eth_proto_ip             ; ip = 00
  beq @ip
  cmp #eth_proto_arp            ; arp = 06
  beq @arp
@done:
  rts

@arp:
  inc ip65_ctr_arp
  jmp arp_process

@ip:
  inc ip65_ctr_ip
  jmp ip_process



; -- LICENSE FOR ip65.s --
; The contents of this file are subject to the Mozilla Public License
; Version 1.1 (the "License"); you may not use this file except in
; compliance with the License. You may obtain a copy of the License at
; http://www.mozilla.org/MPL/
;
; Software distributed under the License is distributed on an "AS IS"
; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
; License for the specific language governing rights and limitations
; under the License.
;
; The Original Code is ip65.
;
; The Initial Developer of the Original Code is Per Olofsson,
; MagerValp@gmail.com.
; Portions created by the Initial Developer are Copyright (C) 2009
; Per Olofsson. All Rights Reserved.
; -- LICENSE END --