/* revision history
 * 19.Aug.2004 yyc  [1.7E] UDP rcvd/send_udp_hdr variable bug fix
 * 09.Aug.2004 yyc  [1.7D] UDP rcvd/send_udp_hdr variable bug test
 * 02.Aug.2004 yyc  [1.7C] ezcfg X2 test
 * 22.Apr.2004 yyc  [1.7B] ezcfg X2 mode bug fix again (PROBE + WRITE)
 *                  add runtime CKCON monitoring module
 * 22.Apr.2004 yyc  [1.7A] ezcfg X2 mode bug fix
 * 09.Dec.2003 yyc  [1.6E] ATC PLIP? address update bug fix
 * 27.Nov.2003 yyc  [1.6D] ATC PLIP? run-time IP address output
 * 19.Nov.2003 yyc  [1.6C] T2S peer ip lock
 *                  ezcfg TCP state view support
 * 05.Sep.2003 yyc  [1.6B] careful watchdog reset
 * 21.Jun.2003 yyc  [1.6A] fix eeprom problem completely
 *                  activate PPPoE always in COD/ATC
 * 12.Jun.2003 yyc  [1.5H] add bootup arp announce code
 * 09.Jun.2003 yyc  [1.5G] TCP simultaneous open support for S2S mode
 * 20.Mar.2003 yyc  [1.5F] reset watchdog before writing env in atstat.c
 * 21.Jan.2003 yyc  [1.5E] ezl50 to ezl50 retransmission bug fix
 *                  make net_mask zero if local_ip is equal to gate_ip(DHCP only)
 * 18.Dec.2002 yyc  [1.5D] PPPoE compiler bug fix (pppoe_tag() function)
 * 11.Dec.2002 yyc  [1.5C] set ESF_7BIT if UART data bit is 7
 * 27.Nov.2002 yyc  [1.5B] make RS485 output active high
 * 05.Nov.2002 yyc  [1.5A] 485, parity, XON/OFF commercial release
 *                  add BOOT1.3B bug work around code
 * 04.Nov.2002 yyc  [1.4H] XON/XOFF support
 *                  U2S multi-cast support
 * 16.Oct.2002 yyc  [1.4G] init esio_flags for parity in t2s/atc/cod/u2s
 * 10.Oct.2002 yyc  [1.4F] U2S RS485 mode support
 * 09.Oct.2002 yyc  [1.4E] set max_mux to 3 in u2s.c
 * 26.Sep.2002 yyc  [1.4D] env-fcs code added for ATC mode
 * 17.Sep.2002 yyc  [1.4C] update sio_rx_count in u2s mode
 * 25.Jul.2002 yyc  [1.4B] add oem_string to env-block
 * 24.Jul.2002 yyc  [1.4A] U2S mode support
 * 24.Jun.2002 yyc  [1.3C] TCP duplicate SYN-rcvd bug fix
 * 20.Jun.2002 yyc  [1.3B] +plp command store local port to env block
 * 03.May.2002 yyc  [1.3A] clean up DHCP & relevant modules
 *                  add arp_router_probe function(t2s only)
 *                  add arp_probe field on env structure
 * 21.Mar.2002 yyc  [1.2N] TCP closure bug fix at online command state
 * 22.Jan.2002 yyc  [1.2M] 14400bps support
 * 22.Dec.2001 yyc  [1.2L] randomize power-on rand_seed in init.msa
 *                         AT+PID, AT+PPW cmd added for PPPoE
 * 13.Dec.2001 yyc  [1.2K] send ADT when terminate PPPoE
 * 11.Dec.2001 yyc  [1.2J] modify timeout period(COD retry)
 *                         add PPPoE ACCOOKIE processing routine
 * 20.Nov.2001 yyc  [1.2I] add tcp_send_timeout timer
 * 19.Nov.2001 yyc  [1.2H] status view sio_count swap(rx <-> tx)
 * 07.Nov.2001 yyc  [1.2G] avoid recv time invalidation by keep-alive segment
 *                  change type of dur-arg in start_tcp_timer (int -> _u16)
 * 06.Nov.2001 yyc  [1.2F] atc mode '+plip' bug fix
 * 02.Nov.2001 yyc  [1.2E] retransmit count bug fix
 * 02.Nov.2001 yyc  [1.2D] keep-alive response bug fix
 * 02.Nov.2001 yyc  [1.2C] authentication flag bug fix
 * 02.Nov.2001 yyc  [1.2B] enable DHCP/PPPoE
 * 24.Oct.2001 yyc  [1.2A] ezl_local_ip moved to idata.c for dynamic ARP reply
 *                  OTP version updated to V1.1A
 *                  snake-leg added for backword compatibility
 * ??.Sep.2001 yyc  [1.1A] official EZL-50 firmware including PPPoE and DHCP
 * 12.Jul.2001 yyc  [1.0A] announce T2S beta
 * 19.Jun.2001 yyc  [----] clean up boot-code
 * 18.Jun.2001 yyc  [----] boot-code initial release
 */