340 lines
8.4 KiB
C
340 lines
8.4 KiB
C
/* -*- C -*- */
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/*
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* Copyright (c) 2005, Swedish Institute of Computer Science
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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* @(#)$Id: slip.c,v 1.6 2008/02/03 20:43:35 adamdunkels Exp $
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*/
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#include <stdio.h>
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#include <string.h>
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#include "contiki.h"
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#include "net/uip.h"
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#include "net/uip-fw.h"
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#define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
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#include "dev/slip.h"
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#define SLIP_END 0300
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#define SLIP_ESC 0333
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#define SLIP_ESC_END 0334
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#define SLIP_ESC_ESC 0335
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PROCESS(slip_process, "SLIP driver");
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u8_t slip_active;
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#if 1
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#define SLIP_STATISTICS(statement)
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#else
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u16_t slip_rubbish, slip_twopackets, slip_overflow, slip_ip_drop;
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#define SLIP_STATISTICS(statement) statement
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#endif
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/* Must be at least one byte larger than UIP_BUFSIZE! */
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#define RX_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN + 16)
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enum {
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STATE_TWOPACKETS = 0, /* We have 2 packets and drop incoming data. */
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STATE_OK = 1,
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STATE_ESC = 2,
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STATE_RUBBISH = 3,
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};
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/*
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* Variables begin and end manage the buffer space in a cyclic
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* fashion. The first used byte is at begin and end is one byte past
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* the last. I.e. [begin, end) is the actively used space.
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*
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* If begin != pkt_end we have a packet at [begin, pkt_end),
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* furthermore, if state == STATE_TWOPACKETS we have one more packet at
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* [pkt_end, end). If more bytes arrive in state STATE_TWOPACKETS
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* they are discarded.
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*/
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static u8_t state = STATE_TWOPACKETS;
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static u16_t begin, end;
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static u8_t rxbuf[RX_BUFSIZE];
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static u16_t pkt_end; /* SLIP_END tracker. */
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/*---------------------------------------------------------------------------*/
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u8_t
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slip_send(void)
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{
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u16_t i;
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u8_t *ptr;
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u8_t c;
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slip_arch_writeb(SLIP_END);
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ptr = &uip_buf[UIP_LLH_LEN];
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for(i = 0; i < uip_len; ++i) {
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if(i == UIP_TCPIP_HLEN) {
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ptr = (u8_t *)uip_appdata;
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}
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c = *ptr++;
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if(c == SLIP_END) {
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slip_arch_writeb(SLIP_ESC);
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c = SLIP_ESC_END;
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} else if(c == SLIP_ESC) {
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slip_arch_writeb(SLIP_ESC);
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c = SLIP_ESC_ESC;
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}
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slip_arch_writeb(c);
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}
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slip_arch_writeb(SLIP_END);
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return UIP_FW_OK;
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}
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u8_t
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slip_write(const void *_ptr, int len)
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{
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const u8_t *ptr = _ptr;
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u16_t i;
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u8_t c;
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slip_arch_writeb(SLIP_END);
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for(i = 0; i < len; ++i) {
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c = *ptr++;
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if(c == SLIP_END) {
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slip_arch_writeb(SLIP_ESC);
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c = SLIP_ESC_END;
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} else if(c == SLIP_ESC) {
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slip_arch_writeb(SLIP_ESC);
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c = SLIP_ESC_ESC;
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}
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slip_arch_writeb(c);
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}
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slip_arch_writeb(SLIP_END);
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return len;
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}
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/*---------------------------------------------------------------------------*/
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static void
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rxbuf_init(void)
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{
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begin = end = pkt_end = 0;
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state = STATE_OK;
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}
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/*---------------------------------------------------------------------------*/
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/* Upper half does the polling. */
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static u16_t
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slip_poll_handler(u8_t *outbuf, u16_t blen)
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{
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/* This is a hack and won't work across buffer edge! */
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if(rxbuf[begin] == 'C') {
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int i;
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if(begin < end && (end - begin) >= 6
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&& memcmp(&rxbuf[begin], "CLIENT", 6) == 0) {
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state = STATE_TWOPACKETS; /* Interrupts do nothing. */
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memset(&rxbuf[begin], 0x0, 6);
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rxbuf_init();
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for(i = 0; i < 13; i++) {
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slip_arch_writeb("CLIENTSERVER\300"[i]);
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}
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return 0;
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}
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}
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/*
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* Interrupt can not change begin but may change pkt_end.
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* If pkt_end != begin it will not change again.
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*/
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if(begin != pkt_end) {
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u16_t len;
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if(begin < pkt_end) {
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len = pkt_end - begin;
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if(len > blen) {
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len = 0;
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} else {
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memcpy(outbuf, &rxbuf[begin], len);
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}
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} else {
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len = (RX_BUFSIZE - begin) + (pkt_end - 0);
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if(len > blen) {
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len = 0;
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} else {
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unsigned i;
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for(i = begin; i < RX_BUFSIZE; i++)
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*outbuf++ = rxbuf[i];
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for(i = 0; i < pkt_end; i++)
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*outbuf++ = rxbuf[i];
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}
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}
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/* Remove data from buffer together with the copied packet. */
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begin = pkt_end;
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if(state == STATE_TWOPACKETS) {
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pkt_end = end;
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state = STATE_OK; /* Assume no bytes where lost! */
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/* One more packet is buffered, need to be polled again! */
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process_poll(&slip_process);
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}
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return len;
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}
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return 0;
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}
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/*---------------------------------------------------------------------------*/
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PROCESS_THREAD(slip_process, ev, data)
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{
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PROCESS_BEGIN();
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rxbuf_init();
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while(1) {
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PROCESS_YIELD();
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slip_active = 1;
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/* Move packet from rxbuf to buffer provided by uIP. */
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uip_len = slip_poll_handler(&uip_buf[UIP_LLH_LEN],
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UIP_BUFSIZE - UIP_LLH_LEN);
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if(uip_len == 4 && strncmp((char*)&uip_buf[UIP_LLH_LEN], "?IPA", 4) == 0) {
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char buf[8];
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memcpy(&buf[0], "=IPA", 4);
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memcpy(&buf[4], &uip_hostaddr, 4);
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slip_write(buf, 8);
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} else if(uip_len > 0
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&& uip_len == (((u16_t)(BUF->len[0]) << 8) + BUF->len[1])
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&& uip_ipchksum() == 0xffff) {
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#define IP_DF 0x40
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if(BUF->ipid[0] == 0 && BUF->ipid[1] == 0 && BUF->ipoffset[0] & IP_DF) {
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static u16_t ip_id;
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u16_t nid = ip_id++;
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BUF->ipid[0] = nid >> 8;
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BUF->ipid[1] = nid;
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nid = htons(nid);
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nid = ~nid; /* negate */
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BUF->ipchksum += nid; /* add */
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if(BUF->ipchksum < nid) { /* 1-complement overflow? */
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BUF->ipchksum++;
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}
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}
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tcpip_input();
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} else {
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uip_len = 0;
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SLIP_STATISTICS(slip_ip_drop++);
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}
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}
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PROCESS_END();
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}
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/*---------------------------------------------------------------------------*/
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int
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slip_input_byte(unsigned char c)
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{
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switch(state) {
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case STATE_RUBBISH:
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if(c == SLIP_END) {
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state = STATE_OK;
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}
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return 0;
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case STATE_TWOPACKETS: /* Two packets are already buffered! */
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return 0;
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case STATE_ESC:
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if(c == SLIP_ESC_END) {
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c = SLIP_END;
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} else if(c == SLIP_ESC_ESC) {
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c = SLIP_ESC;
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} else {
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state = STATE_RUBBISH;
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SLIP_STATISTICS(slip_rubbish++);
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end = pkt_end; /* remove rubbish */
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return 0;
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}
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state = STATE_OK;
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break;
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case STATE_OK:
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if(c == SLIP_ESC) {
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state = STATE_ESC;
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return 0;
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} else if(c == SLIP_END) {
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/*
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* We have a new packet, possibly of zero length.
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*
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* There may already be one packet buffered.
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*/
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if(end != pkt_end) { /* Non zero length. */
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if(begin == pkt_end) { /* None buffered. */
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pkt_end = end;
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} else {
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state = STATE_TWOPACKETS;
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SLIP_STATISTICS(slip_twopackets++);
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}
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process_poll(&slip_process);
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return 1;
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}
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return 0;
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}
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break;
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}
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/* add_char: */
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{
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unsigned next;
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next = end + 1;
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if(next == RX_BUFSIZE) {
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next = 0;
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}
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if(next == begin) { /* rxbuf is full */
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state = STATE_RUBBISH;
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SLIP_STATISTICS(slip_overflow++);
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end = pkt_end; /* remove rubbish */
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return 0;
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}
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rxbuf[end] = c;
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end = next;
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}
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/* There could be a separate poll routine for this. */
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if(c == 'T' && rxbuf[begin] == 'C') {
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process_poll(&slip_process);
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return 1;
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}
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return 0;
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}
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/*---------------------------------------------------------------------------*/
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