lwIP Ethernet Driver (rm_lwip_ether)

Functions
err_t	rm_lwip_ether_init (struct netif *p_netif)
void	rm_lwip_ether_callback (ether_callback_args_t *p_args)

Detailed Description

Overview

This module provides a lwIP driver that is implemented using the Ethernet Interface.

Please refer to the lwIP documentation for further details.

Features

• Packet Types Supported
  • ARP
  • IPv4
  • IPv6
• UDP (User Datagram Protocol) including experimental UDP-lite extensions
• TCP (Transmission Control Protocol) with congestion control, RTT estimation fast recovery/fast retransmit and sending SACKs
• raw/native API for enhanced performance
• Link status callback

Configuration

Configurations for Networking > lwIP Wrapper to (rm_lwip_ether)

Configuration	Options	Default	Description
RTOS
RX thread stacksize	Must be a positive integer	1024	Stack size of RX thread.
RX thread priority	Must be a positive integer	4	Priority of RX thread.
Name	Name must be a valid C symbol	g_lwip_ether0	Module name.
MTU	Must be an integer from 576 to 1500	1500	MTU size.
Netif flags	UP BROADCAST LINK_UP ETHARP ETHERNET IGMP MLD6	BROADCAST ETHARP	Flags representing the capabilities of the Ethernet device
Zero-copy mode	Disable Enable	Disable	Enable or disable zero-copy mode.
RX buffer pool size	Must be a positive integer	10	Buffer pool size for zero-copy RX.
Link check interval	Must be a positive integer	100	Interval for checking link status.

Usage Notes

Limitations

Examples

Basic Example

This is a basic example of minimal use of the lwIP Ether Driver in an application.

#include "lwip/tcp.h"
#include "lwip/timeouts.h"
#include "lwip/init.h"
#include "lwip/ip4.h"

#define LWIP_EXAMPLE_PORT_NUMBER    9000

/* TCP callback functions. */
static err_t lwip_example_connected_callback(void * arg, struct tcp_pcb * tpcb, err_t err);
err_t        lwip_example_sent_callback(void * arg, struct tcp_pcb * tpcb, u16_t len);
err_t        lwip_example_recv_callback(void * arg, struct tcp_pcb * tpcb, struct pbuf * p, err_t err);

volatile uint8_t g_lwip_example_connected_flag;
volatile uint8_t g_lwip_example_sent_flag;
volatile uint8_t g_lwip_example_recv_flag;

void rm_lwip_ether_example () {
    struct netif     netif;
    struct tcp_pcb * pcb = NULL;

    ip_addr_t ipaddr;
    ip_addr_t netmask;
    ip_addr_t gw;

    ip_addr_t server_ip;

    const char data[] = "lwIP Hello world.";

    /* Initializing lwIP core. */
    lwip_init();

    /* Set ip address of the board. */
    IP4_ADDR(&ipaddr, 192, 168, 10, 4);
    IP4_ADDR(&netmask, 255, 255, 255, 0);
    IP4_ADDR(&gw, 192, 168, 10, 1);

    /* Initialize netif. Please pass rm_lwip_ether_init() function and the instance of rm_lwip_ether to netif_add(). */
    netif_add(&netif, &ipaddr, &netmask, &gw, &g_lwip_ether_instance, rm_lwip_ether_init, netif_input);

    /* Set netif as default and enable */
    netif_set_default(&netif);
    netif_set_up(&netif);
    netif_set_link_up(&netif);

    /* Create a pcb for client. */
    pcb = tcp_new();

    /* Start connection to the server. */
    g_lwip_example_connected_flag = false;
    IP4_ADDR(&server_ip, 192, 168, 10, 1);
    tcp_connect(pcb, &server_ip, LWIP_EXAMPLE_PORT_NUMBER, lwip_example_connected_callback);

    /* Waiting for connection to be established. */
    while (false == g_lwip_example_connected_flag)
    {
        R_BSP_SoftwareDelay(1, BSP_DELAY_UNITS_MILLISECONDS);
        sys_check_timeouts();
    }

    /* Set callback for receiving complete. */
    g_lwip_example_recv_flag = false;
    tcp_recv(pcb, lwip_example_recv_callback);

    /* Set callback for sending complete. */
    g_lwip_example_sent_flag = false;
    tcp_sent(pcb, lwip_example_sent_callback);

    /* Send a message. */
    tcp_write(pcb, data, sizeof(data), TCP_WRITE_FLAG_COPY);
    while (false == g_lwip_example_sent_flag)
    {
        R_BSP_SoftwareDelay(1, BSP_DELAY_UNITS_MILLISECONDS);
        sys_check_timeouts();
    }

    while (false == g_lwip_example_recv_flag)
    {
        R_BSP_SoftwareDelay(1, BSP_DELAY_UNITS_MILLISECONDS);
        sys_check_timeouts();
    }

    /* Close TCP client and netif. */
    tcp_close(pcb);
    netif_remove(&netif);
}

err_t lwip_example_connected_callback (void * arg, struct tcp_pcb * tpcb, err_t err) {
    FSP_PARAMETER_NOT_USED(arg);
    FSP_PARAMETER_NOT_USED(err);
    FSP_PARAMETER_NOT_USED(tpcb);

    g_lwip_example_connected_flag = true;

    return err;
}

err_t lwip_example_sent_callback (void * arg, struct tcp_pcb * tpcb, u16_t len) {
    FSP_PARAMETER_NOT_USED(arg);
    FSP_PARAMETER_NOT_USED(tpcb);
    FSP_PARAMETER_NOT_USED(len);

    g_lwip_example_sent_flag = true;

    return ERR_OK;
}

err_t lwip_example_recv_callback (void * arg, struct tcp_pcb * tpcb, struct pbuf * p, err_t err) {
    FSP_PARAMETER_NOT_USED(arg);
    FSP_PARAMETER_NOT_USED(tpcb);
    FSP_PARAMETER_NOT_USED(err);

    g_lwip_example_recv_flag = true;

    /* If the callback function returns ERR_OK it must have freed the pbuf, otherwise it must not have freed it. */
    if (p != NULL)
    {
        pbuf_free(p);
    }

    return ERR_OK;
}

Function Documentation

rm_lwip_ether_init()

err_t rm_lwip_ether_init

(

struct netif *

p_netif

)

Initialize ethernet hardware and lwIP network interface. This function is passed to netif_add()

rm_lwip_ether_callback()

void rm_lwip_ether_callback

(

ether_callback_args_t *

p_args

)

Callback of Ethernet interrupt subroutine. This function is set to ethernet driver callback by configurator.