lwIP 2.2.1 Lightweight IP stack

Functions
SLIP
NETIFs

## Functions
err_t | slipif_init (struct netif *netif)
void | slipif_poll (struct netif *netif)
void | slipif_process_rxqueue (struct netif *netif)
void | slipif_received_byte (struct netif *netif, u8_t data)
void | slipif_received_bytes (struct netif *netif, u8_t *data, u8_t len)

## 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.

## ◆ 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

## ◆ slipif_process_rxqueue()

void slipif_process_rxqueue | ( | struct netif * | netif | ) |

Feeds the IP layer with incoming packets that were receive

Parameters

  netif | The lwip network interface structure for this slipif

## ◆ slipif_received_byte()

void slipif_received_byte | ( | struct netif * | netif,
|  | u8_t | data
| ) |  |

Process a received byte, completed packets are put on a queue that is fed into IP through slipif_process_rxqueue().

This function can be called from ISR if SYS_LIGHTWEIGHT_PROT is enabled.

Parameters

  netif | The lwip network interface structure for this slipif
  data | received character

## ◆ slipif_received_bytes()

void slipif_received_bytes | ( | struct netif * | netif,
|  | u8_t * | data,
|  | u8_t | len
| ) |  |

Process multiple received byte, completed packets are put on a queue that is fed into IP through slipif_process_rxqueue().

This function can be called from ISR if SYS_LIGHTWEIGHT_PROT is enabled.

Parameters

  netif | The lwip network interface structure for this slipif
  data | received character
  len | Number of received characters