SLIP

Collaboration diagram for SLIP:

Functions
err_t	slipif_init (struct netif *netif)
void	slipif_poll (struct netif *netif)

Detailed Description

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

Usage: This netif can be used in three ways:

1. For NO_SYS==0, an RX thread can be used which blocks on sio_read() until data is received.
2. In your main loop, call slipif_poll() to check for new RX bytes, completed packets are fed into netif->input().
3. Call slipif_received_byte[s]() from your serial RX ISR and slipif_process_rxqueue() from your main loop. ISR level decodes packets and puts completed packets on a queue which is fed into the stack from the main loop (needs SYS_LIGHTWEIGHT_PROT for pbuf_alloc to work on ISR level!).

Function Documentation

slipif_init()

err_t slipif_init

(

struct netif *

netif

)

SLIP netif initialization

Call the arch specific sio_open and remember the opened device in the state field of the netif.

Parameters

netif

the lwip network interface structure for this slipif

Returns

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

If netif->state is interpreted as an u8_t serial port number.

Definition at line 360 of file slipif.c.

{
  struct slipif_priv *priv;
  u8_t sio_num;
 
  LWIP_ASSERT("slipif needs an input callback", netif->input != NULL);
 
  /* netif->state contains serial port number */
  sio_num = LWIP_PTR_NUMERIC_CAST(u8_t, netif->state);
 
  LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)sio_num));
 
  /* Allocate private data */
  priv = (struct slipif_priv *)mem_malloc(sizeof(struct slipif_priv));
  if (!priv) {
    return ERR_MEM;
  }
 
  netif->name[0] = 's';
  netif->name[1] = 'l';
#if LWIP_IPV4
  netif->output = slipif_output_v4;
#endif /* LWIP_IPV4 */
#if LWIP_IPV6
  netif->output_ip6 = slipif_output_v6;
#endif /* LWIP_IPV6 */
  netif->mtu = SLIP_MAX_SIZE;
 
  /* Try to open the serial port. */
  priv->sd = sio_open(sio_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;
#if SLIP_RX_FROM_ISR
  priv->rxpackets = NULL;
#endif
 
  netif->state = priv;
 
  /* initialize the snmp variables and counters inside the struct netif */
  MIB2_INIT_NETIF(netif, snmp_ifType_slip, SLIP_SIO_SPEED(priv->sd));
 
#if SLIP_USE_RX_THREAD
  /* Create a thread to poll the serial line. */
  sys_thread_new(SLIPIF_THREAD_NAME, slipif_loop_thread, netif,
                 SLIPIF_THREAD_STACKSIZE, SLIPIF_THREAD_PRIO);
#endif /* SLIP_USE_RX_THREAD */
  return ERR_OK;
}

slipif_poll()

void slipif_poll

(

struct netif *

netif

)

Polls the serial device and feeds the IP layer with incoming packets.

Parameters

netif

The lwip network interface structure for this slipif

Definition at line 426 of file slipif.c.

{
  u8_t c;
  struct slipif_priv *priv;
 
  LWIP_ASSERT("netif != NULL", (netif != NULL));
  LWIP_ASSERT("netif->state != NULL", (netif->state != NULL));
 
  priv = (struct slipif_priv *)netif->state;
 
  while (sio_tryread(priv->sd, &c, 1) > 0) {
    slipif_rxbyte_input(netif, c);
  }
}