minix/lib/liblwip/netif/slipif.c

368 lines
10 KiB
C
Raw Normal View History

/**
* @file
* SLIP Interface
*
*/
/*
* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is built upon the file: src/arch/rtxc/netif/sioslip.c
*
* Author: Magnus Ivarsson <magnus.ivarsson(at)volvo.com>
*/
/*
* This is an arch independent SLIP netif. The specific serial hooks must be
* provided by another file. They are sio_open, sio_read/sio_tryread and sio_send
*/
#include "netif/slipif.h"
#include "lwip/opt.h"
#if LWIP_HAVE_SLIPIF
#include "lwip/def.h"
#include "lwip/pbuf.h"
#include "lwip/sys.h"
#include "lwip/stats.h"
#include "lwip/snmp.h"
#include "lwip/sio.h"
#define SLIP_BLOCK 1
#define SLIP_DONTBLOCK 0
#define SLIP_END 0300 /* 0xC0 */
#define SLIP_ESC 0333 /* 0xDB */
#define SLIP_ESC_END 0334 /* 0xDC */
#define SLIP_ESC_ESC 0335 /* 0xDD */
#define SLIP_MAX_SIZE 1500
enum slipif_recv_state {
SLIP_RECV_NORMAL,
SLIP_RECV_ESCAPE,
};
struct slipif_priv {
sio_fd_t sd;
/* q is the whole pbuf chain for a packet, p is the current pbuf in the chain */
struct pbuf *p, *q;
enum slipif_recv_state state;
u16_t i, recved;
};
/**
* Send a pbuf doing the necessary SLIP encapsulation
*
* Uses the serial layer's sio_send()
*
* @param netif the lwip network interface structure for this slipif
* @param p the pbuf chaing packet to send
* @param ipaddr the ip address to send the packet to (not used for slipif)
* @return always returns ERR_OK since the serial layer does not provide return values
*/
err_t
slipif_output(struct netif *netif, struct pbuf *p, ip_addr_t *ipaddr)
{
struct slipif_priv *priv;
struct pbuf *q;
u16_t i;
u8_t c;
LWIP_ASSERT("netif != NULL", (netif != NULL));
LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
LWIP_ASSERT("p != NULL", (p != NULL));
LWIP_UNUSED_ARG(ipaddr);
priv = netif->state;
/* Send pbuf out on the serial I/O device. */
sio_send(SLIP_END, priv->sd);
for (q = p; q != NULL; q = q->next) {
for (i = 0; i < q->len; i++) {
c = ((u8_t *)q->payload)[i];
switch (c) {
case SLIP_END:
sio_send(SLIP_ESC, priv->sd);
sio_send(SLIP_ESC_END, priv->sd);
break;
case SLIP_ESC:
sio_send(SLIP_ESC, priv->sd);
sio_send(SLIP_ESC_ESC, priv->sd);
break;
default:
sio_send(c, priv->sd);
break;
}
}
}
sio_send(SLIP_END, priv->sd);
return ERR_OK;
}
/**
* Static function for easy use of blockig or non-blocking
* sio_read
*
* @param fd serial device handle
* @param data pointer to data buffer for receiving
* @param len maximum length (in bytes) of data to receive
* @param block if 1, call sio_read; if 0, call sio_tryread
* @return return value of sio_read of sio_tryread
*/
static u32_t
slip_sio_read(sio_fd_t fd, u8_t* data, u32_t len, u8_t block)
{
if (block) {
return sio_read(fd, data, len);
} else {
return sio_tryread(fd, data, len);
}
}
/**
* Handle the incoming SLIP stream character by character
*
* Poll the serial layer by calling sio_read() or sio_tryread().
*
* @param netif the lwip network interface structure for this slipif
* @param block if 1, block until data is received; if 0, return when all data
* from the buffer is received (multiple calls to this function will
* return a complete packet, NULL is returned before - used for polling)
* @return The IP packet when SLIP_END is received
*/
static struct pbuf *
slipif_input(struct netif *netif, u8_t block)
{
struct slipif_priv *priv;
u8_t c;
struct pbuf *t;
LWIP_ASSERT("netif != NULL", (netif != NULL));
LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
priv = netif->state;
while (slip_sio_read(priv->sd, &c, 1, block) > 0) {
switch (priv->state) {
case SLIP_RECV_NORMAL:
switch (c) {
case SLIP_END:
if (priv->recved > 0) {
/* Received whole packet. */
/* Trim the pbuf to the size of the received packet. */
pbuf_realloc(priv->q, priv->recved);
LINK_STATS_INC(link.recv);
LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet\n"));
t = priv->q;
priv->p = priv->q = NULL;
priv->i = priv->recved = 0;
return t;
}
continue;
case SLIP_ESC:
priv->state = SLIP_RECV_ESCAPE;
continue;
}
break;
case SLIP_RECV_ESCAPE:
switch (c) {
case SLIP_ESC_END:
c = SLIP_END;
break;
case SLIP_ESC_ESC:
c = SLIP_ESC;
break;
}
priv->state = SLIP_RECV_NORMAL;
/* FALLTHROUGH */
}
/* byte received, packet not yet completely received */
if (priv->p == NULL) {
/* allocate a new pbuf */
LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN), PBUF_POOL);
if (priv->p == NULL) {
LINK_STATS_INC(link.drop);
LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
/* don't process any further since we got no pbuf to receive to */
break;
}
if (priv->q != NULL) {
/* 'chain' the pbuf to the existing chain */
pbuf_cat(priv->q, priv->p);
} else {
/* p is the first pbuf in the chain */
priv->q = priv->p;
}
}
/* this automatically drops bytes if > SLIP_MAX_SIZE */
if ((priv->p != NULL) && (priv->recved <= SLIP_MAX_SIZE)) {
((u8_t *)priv->p->payload)[priv->i] = c;
priv->recved++;
priv->i++;
if (priv->i >= priv->p->len) {
/* on to the next pbuf */
priv->i = 0;
if (priv->p->next != NULL && priv->p->next->len > 0) {
/* p is a chain, on to the next in the chain */
priv->p = priv->p->next;
} else {
/* p is a single pbuf, set it to NULL so next time a new
* pbuf is allocated */
priv->p = NULL;
}
}
}
}
return NULL;
}
#if !NO_SYS
/**
* The SLIP input thread.
*
* Feed the IP layer with incoming packets
*
* @param nf the lwip network interface structure for this slipif
*/
static void
slipif_loop_thread(void *nf)
{
struct pbuf *p;
struct netif *netif = (struct netif *)nf;
while (1) {
p = slipif_input(netif, SLIP_BLOCK);
if (p != NULL) {
if (netif->input(p, netif) != ERR_OK) {
pbuf_free(p);
p = NULL;
}
}
}
}
#endif /* !NO_SYS */
/**
* SLIP netif initialization
*
* Call the arch specific sio_open and remember
* the opened device in the state field of the netif.
*
* @param netif the lwip network interface structure for this slipif
* @return ERR_OK if serial line could be opened,
* ERR_MEM if no memory could be allocated,
* ERR_IF is serial line couldn't be opened
*
* @note netif->num must contain the number of the serial port to open
* (0 by default)
*/
err_t
slipif_init(struct netif *netif)
{
struct slipif_priv *priv;
LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)netif->num));
/* Allocate private data */
priv = mem_malloc(sizeof(struct slipif_priv));
if (!priv) {
return ERR_MEM;
}
netif->name[0] = 's';
netif->name[1] = 'l';
netif->output = slipif_output;
netif->mtu = SLIP_MAX_SIZE;
netif->flags |= NETIF_FLAG_POINTTOPOINT;
/* Try to open the serial port (netif->num contains the port number). */
priv->sd = sio_open(netif->num);
if (!priv->sd) {
/* Opening the serial port failed. */
mem_free(priv);
return ERR_IF;
}
/* Initialize private data */
priv->p = NULL;
priv->q = NULL;
priv->state = SLIP_RECV_NORMAL;
priv->i = 0;
priv->recved = 0;
netif->state = priv;
/* initialize the snmp variables and counters inside the struct netif
* ifSpeed: no assumption can be made without knowing more about the
* serial line!
*/
NETIF_INIT_SNMP(netif, snmp_ifType_slip, 0);
/* Create a thread to poll the serial line. */
sys_thread_new(SLIPIF_THREAD_NAME, slipif_loop_thread, netif,
SLIPIF_THREAD_STACKSIZE, SLIPIF_THREAD_PRIO);
return ERR_OK;
}
/**
* Polls the serial device and feeds the IP layer with incoming packets.
*
* @param netif The lwip network interface structure for this slipif
*/
void
slipif_poll(struct netif *netif)
{
struct pbuf *p;
struct slipif_priv *priv;
LWIP_ASSERT("netif != NULL", (netif != NULL));
LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
priv = netif->state;
while ((p = slipif_input(netif, SLIP_DONTBLOCK)) != NULL) {
if (netif->input(p, netif) != ERR_OK) {
pbuf_free(p);
}
}
}
#endif /* LWIP_HAVE_SLIPIF */