367 lines
10 KiB
C
367 lines
10 KiB
C
/**
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* @file
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* SLIP Interface
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*
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*/
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/*
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* Copyright (c) 2001-2004 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 built upon the file: src/arch/rtxc/netif/sioslip.c
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*
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* Author: Magnus Ivarsson <magnus.ivarsson(at)volvo.com>
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*/
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/*
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* This is an arch independent SLIP netif. The specific serial hooks must be
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* provided by another file. They are sio_open, sio_read/sio_tryread and sio_send
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*/
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#include "netif/slipif.h"
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#include "lwip/opt.h"
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#if LWIP_HAVE_SLIPIF
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#include "lwip/def.h"
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#include "lwip/pbuf.h"
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#include "lwip/sys.h"
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#include "lwip/stats.h"
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#include "lwip/snmp.h"
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#include "lwip/sio.h"
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#define SLIP_BLOCK 1
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#define SLIP_DONTBLOCK 0
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#define SLIP_END 0300 /* 0xC0 */
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#define SLIP_ESC 0333 /* 0xDB */
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#define SLIP_ESC_END 0334 /* 0xDC */
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#define SLIP_ESC_ESC 0335 /* 0xDD */
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#define SLIP_MAX_SIZE 1500
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enum slipif_recv_state {
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SLIP_RECV_NORMAL,
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SLIP_RECV_ESCAPE,
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};
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struct slipif_priv {
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sio_fd_t sd;
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/* q is the whole pbuf chain for a packet, p is the current pbuf in the chain */
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struct pbuf *p, *q;
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enum slipif_recv_state state;
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u16_t i, recved;
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};
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/**
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* Send a pbuf doing the necessary SLIP encapsulation
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*
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* Uses the serial layer's sio_send()
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*
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* @param netif the lwip network interface structure for this slipif
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* @param p the pbuf chaing packet to send
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* @param ipaddr the ip address to send the packet to (not used for slipif)
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* @return always returns ERR_OK since the serial layer does not provide return values
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*/
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err_t
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slipif_output(struct netif *netif, struct pbuf *p, ip_addr_t *ipaddr)
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{
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struct slipif_priv *priv;
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struct pbuf *q;
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u16_t i;
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u8_t c;
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LWIP_ASSERT("netif != NULL", (netif != NULL));
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LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
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LWIP_ASSERT("p != NULL", (p != NULL));
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LWIP_UNUSED_ARG(ipaddr);
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priv = netif->state;
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/* Send pbuf out on the serial I/O device. */
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sio_send(SLIP_END, priv->sd);
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for (q = p; q != NULL; q = q->next) {
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for (i = 0; i < q->len; i++) {
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c = ((u8_t *)q->payload)[i];
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switch (c) {
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case SLIP_END:
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sio_send(SLIP_ESC, priv->sd);
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sio_send(SLIP_ESC_END, priv->sd);
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break;
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case SLIP_ESC:
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sio_send(SLIP_ESC, priv->sd);
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sio_send(SLIP_ESC_ESC, priv->sd);
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break;
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default:
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sio_send(c, priv->sd);
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break;
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}
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}
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}
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sio_send(SLIP_END, priv->sd);
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return ERR_OK;
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}
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/**
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* Static function for easy use of blockig or non-blocking
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* sio_read
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*
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* @param fd serial device handle
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* @param data pointer to data buffer for receiving
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* @param len maximum length (in bytes) of data to receive
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* @param block if 1, call sio_read; if 0, call sio_tryread
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* @return return value of sio_read of sio_tryread
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*/
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static u32_t
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slip_sio_read(sio_fd_t fd, u8_t* data, u32_t len, u8_t block)
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{
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if (block) {
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return sio_read(fd, data, len);
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} else {
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return sio_tryread(fd, data, len);
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}
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}
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/**
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* Handle the incoming SLIP stream character by character
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*
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* Poll the serial layer by calling sio_read() or sio_tryread().
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*
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* @param netif the lwip network interface structure for this slipif
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* @param block if 1, block until data is received; if 0, return when all data
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* from the buffer is received (multiple calls to this function will
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* return a complete packet, NULL is returned before - used for polling)
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* @return The IP packet when SLIP_END is received
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*/
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static struct pbuf *
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slipif_input(struct netif *netif, u8_t block)
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{
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struct slipif_priv *priv;
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u8_t c;
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struct pbuf *t;
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LWIP_ASSERT("netif != NULL", (netif != NULL));
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LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
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priv = netif->state;
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while (slip_sio_read(priv->sd, &c, 1, block) > 0) {
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switch (priv->state) {
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case SLIP_RECV_NORMAL:
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switch (c) {
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case SLIP_END:
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if (priv->recved > 0) {
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/* Received whole packet. */
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/* Trim the pbuf to the size of the received packet. */
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pbuf_realloc(priv->q, priv->recved);
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LINK_STATS_INC(link.recv);
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LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet\n"));
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t = priv->q;
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priv->p = priv->q = NULL;
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priv->i = priv->recved = 0;
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return t;
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}
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continue;
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case SLIP_ESC:
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priv->state = SLIP_RECV_ESCAPE;
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continue;
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}
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break;
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case SLIP_RECV_ESCAPE:
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switch (c) {
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case SLIP_ESC_END:
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c = SLIP_END;
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break;
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case SLIP_ESC_ESC:
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c = SLIP_ESC;
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break;
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}
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priv->state = SLIP_RECV_NORMAL;
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/* FALLTHROUGH */
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}
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/* byte received, packet not yet completely received */
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if (priv->p == NULL) {
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/* allocate a new pbuf */
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LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
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priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN), PBUF_POOL);
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if (priv->p == NULL) {
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LINK_STATS_INC(link.drop);
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LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
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/* don't process any further since we got no pbuf to receive to */
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break;
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}
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if (priv->q != NULL) {
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/* 'chain' the pbuf to the existing chain */
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pbuf_cat(priv->q, priv->p);
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} else {
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/* p is the first pbuf in the chain */
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priv->q = priv->p;
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}
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}
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/* this automatically drops bytes if > SLIP_MAX_SIZE */
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if ((priv->p != NULL) && (priv->recved <= SLIP_MAX_SIZE)) {
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((u8_t *)priv->p->payload)[priv->i] = c;
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priv->recved++;
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priv->i++;
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if (priv->i >= priv->p->len) {
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/* on to the next pbuf */
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priv->i = 0;
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if (priv->p->next != NULL && priv->p->next->len > 0) {
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/* p is a chain, on to the next in the chain */
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priv->p = priv->p->next;
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} else {
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/* p is a single pbuf, set it to NULL so next time a new
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* pbuf is allocated */
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priv->p = NULL;
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}
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}
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}
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}
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return NULL;
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}
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#if !NO_SYS
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/**
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* The SLIP input thread.
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*
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* Feed the IP layer with incoming packets
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*
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* @param nf the lwip network interface structure for this slipif
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*/
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static void
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slipif_loop_thread(void *nf)
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{
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struct pbuf *p;
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struct netif *netif = (struct netif *)nf;
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while (1) {
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p = slipif_input(netif, SLIP_BLOCK);
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if (p != NULL) {
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if (netif->input(p, netif) != ERR_OK) {
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pbuf_free(p);
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p = NULL;
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}
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}
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}
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}
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#endif /* !NO_SYS */
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/**
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* SLIP netif initialization
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*
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* Call the arch specific sio_open and remember
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* the opened device in the state field of the netif.
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*
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* @param netif the lwip network interface structure for this slipif
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* @return ERR_OK if serial line could be opened,
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* ERR_MEM if no memory could be allocated,
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* ERR_IF is serial line couldn't be opened
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*
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* @note netif->num must contain the number of the serial port to open
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* (0 by default)
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*/
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err_t
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slipif_init(struct netif *netif)
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{
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struct slipif_priv *priv;
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LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)netif->num));
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/* Allocate private data */
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priv = mem_malloc(sizeof(struct slipif_priv));
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if (!priv) {
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return ERR_MEM;
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}
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netif->name[0] = 's';
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netif->name[1] = 'l';
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netif->output = slipif_output;
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netif->mtu = SLIP_MAX_SIZE;
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netif->flags |= NETIF_FLAG_POINTTOPOINT;
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/* Try to open the serial port (netif->num contains the port number). */
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priv->sd = sio_open(netif->num);
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if (!priv->sd) {
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/* Opening the serial port failed. */
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mem_free(priv);
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return ERR_IF;
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}
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/* Initialize private data */
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priv->p = NULL;
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priv->q = NULL;
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priv->state = SLIP_RECV_NORMAL;
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priv->i = 0;
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priv->recved = 0;
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netif->state = priv;
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/* initialize the snmp variables and counters inside the struct netif
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* ifSpeed: no assumption can be made without knowing more about the
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* serial line!
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*/
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NETIF_INIT_SNMP(netif, snmp_ifType_slip, 0);
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/* Create a thread to poll the serial line. */
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sys_thread_new(SLIPIF_THREAD_NAME, slipif_loop_thread, netif,
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SLIPIF_THREAD_STACKSIZE, SLIPIF_THREAD_PRIO);
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return ERR_OK;
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}
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/**
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* Polls the serial device and feeds the IP layer with incoming packets.
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*
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* @param netif The lwip network interface structure for this slipif
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*/
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void
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slipif_poll(struct netif *netif)
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{
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struct pbuf *p;
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struct slipif_priv *priv;
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LWIP_ASSERT("netif != NULL", (netif != NULL));
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LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
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priv = netif->state;
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while ((p = slipif_input(netif, SLIP_DONTBLOCK)) != NULL) {
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if (netif->input(p, netif) != ERR_OK) {
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pbuf_free(p);
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}
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}
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}
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#endif /* LWIP_HAVE_SLIPIF */
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