Set up udp communication between board (echo server) and pc (client) based on lwip example

mjx1126 — Thu, 04 Jun 2020 15:33:51 GMT

Hi I'm using lwip_example for mpc5748g in s32ds for power architecture. Based on that example, I wanna build an echo server on the board, so I add the following codes in main.c and call udp_echo_init in the main function. I set up a client on pc and I checked by wireshark that it did send out the message to the ip address of mpc5748g. However, the echo server doesn't work. I think probably I miss setting up something in the main function (maybe ethernet setup and socket but I have no idea). Does anyone have experience on udp communication between such boards and pc before? Any experience would be appreciated!

By the way, is there any way that I can debug the lwip_example by printing out messages? I tried adding a uart component but it seems that it's not allowed in this particular example.

#include "lwip/udp.h"
#include "lwip/debug.h"

void udp_echo_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port)
{
if (p != NULL) {
/* send received packet back to sender */
udp_sendto(pcb, p, addr, port);
/* free the pbuf */
pbuf_free(p);
}
}

void udp_echo_init(void)
{
struct udp_pcb * pcb;

/* get new pcb */
pcb = udp_new();
if (pcb == NULL) {
LWIP_DEBUGF(UDP_DEBUG, ("udp_new failed!\n"));
return;
}

/* bind to any IP address on port 7 */
if (udp_bind(pcb, IP_ADDR_ANY, 7) != ERR_OK) {
LWIP_DEBUGF(UDP_DEBUG, ("udp_bind failed!\n"));
return;
}

/* set udp_echo_recv() as callback function
for received packets */
udp_recv(pcb, udp_echo_recv, NULL);
}

topic Set up udp communication between board (echo server) and pc (client) based on lwip example in S32 Design Studio

Set up udp communication between board (echo server) and pc (client) based on lwip example