Posted on May 20, 2018 at 21:14I have a client/server LWIP program that works correctly with unicast communication however I want to use multicast features so I used IGMP library did the following:
1- in opt.h:
&sharpdefine LWIP_IGMP 1 //allowed IGMP
2- in ethernetif.c:
netif->flags |= NETIF_FLAG_IGMP; //in low_level_init function
3-in my source file (for both client and server projects):
implemented the following code:
void
recCallBack
(void)
{
printf('connected'); //BREAK_POINT
}
static void UDP_Multicast_init(void *arg)
{
struct ip4_addr ipgroup, localIP;
struct udp_pcb *g_udppcb;
char msg[] = 'hello';
struct pbuf* p;
p = pbuf_alloc(PBUF_TRANSPORT,sizeof(msg),PBUF_RAM);
memcpy (p->payload, msg, sizeof(msg));
IP4_ADDR(&ipgroup, 224, 0, 1, 129 ); //Multicast IP address.
IP4_ADDR(&localIP, 192, 168, 1, 2); //Interface IP address
&sharpif LWIP_IGMP
s8_t iret = igmp_joingroup((ip4_addr_t *)(&localIP),(ip4_addr_t *)(&ipgroup));
&sharpendif
g_udppcb =( struct udp_pcb*) udp_new();
udp_bind(g_udppcb, &localIP, 319); //to allow receiving multicast
udp_recv(g_udppcb, recCallBack,NULL); //
recCallBack is
the callback function that will be called every time you receive multicast
udp_sendto(g_udppcb,p,&ipgroup,319); //send a multicast packet
}
void telnet_shell_init(void)
{
sys_thread_new('TELNET', UDP_Multicast_init, NULL, DEFAULT_THREAD_STACKSIZE, osPriorityAboveNormal);
}
The result: all the mentioned code steps are executed successfully in both projects (client and server) but I'm not receiving any multicast messages (or maybe not even sending)!
I added a '
BREAK_POINT' in the callback function but I never reached it. Can you help me? either by suggesting a solution or at least a way to track the problem... I'm using STM32F746 Nucleo board with LWIP, FreeRTOS libraries generated by cubeMX.
Thank you.
#freertos #lwip #udp #stm32f7-nucleo #multicast
