Re: [lwip-users] IGMP Multicast RAW API receive problem

[Amr Elsayed]

Thanks Jens , your Question has pointed out the problem , now I can receive the packets too.

my hardware MAC is stm32f427 and I had the multicast filter enabled so I changed some line on the MAC initialization from 

macinit.MulticastFramesFilter = ETH_MULTICASTFRAMESFILTER_PERFECT;

to

macinit.MulticastFramesFilter = ETH_MULTICASTFRAMESFILTER_NONE;

and after that the board  can receive the packets, may be I need to make use of the filter in the future.

Thanks again.

Best Regards,

Amr Elsayed.

RA @ E-JUST.

Founder & Engineer @ DIY-Life.

address@hidden

+201223240852.

 

On 11 July 2018 at 19:30, Jens Nielsen <address@hidden> wrote:

Hi

On which hardware? You may have to enable reception of multicast frames in your ethernet controller

BR /Jens

On 2018-07-11 02:12, Amr Elsayed wrote:

Dear LWIP users and team, 

I am trying to send and receive IGMP multicast messages using RAW API's , I can only send but can not receive back the messages by a board running the same code (without sending packets).On wireshark I can  see the "IGMP Membership report Group " packets for both devices  and I can also see the UDP messages I send periodically to the multicast IP, but on receiver board having the same code that I also share below I can not receive back the Multicast messages and the udp_recv set callback function is never called. also i tried to put a breakpoint in ip4_input inside the if condition of the  multicast packets but the breakpoint is never getting fired.

  if (ip4_addr_ismulticast(ip4_current_dest_addr())) {

              // ...

  }

so this may do means that the sent UDP message have something wrong despite that I can see the packet on wireshark ? 

I have netif->flags|= NETIF_FLAG_IGMP; and i am sure igmp_start() is called.

to summarize the problem I do have I can join IGMP group and send UDP messages to the multicast IP as on wireshark but I can not receive that message on another board running the same code.

code:

#define MULTICAST_PORT 9533

static char multicast_ip[] = "238.0.0.8";

static char dummyData[] = "Hello from board";

#define UDP_APP_INTERVAL 5000

static struct udp_pcb *multiAppPcb;

static ip_addr_t multicastIp;

static uint32_t multiAppTime = 0 ;

// prototypes

void multicast_init(void);

int multicast_send_data(const char* buff,uint16_t len );.

static void multicast_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p,

                 const ip_addr_t *addr, u16_t port);

void main( void ){

 // .. initializations 

  LWIP_Init();

  multicast_init();

  while(1)

  {

       MX_LWIP_Process(hal_time);

       // only on sender board..

if(time - multiAppTime > UDP_APP_INTERVAL)

{

multiAppTime = time ;

uint16_t totLen = strlen(dummyData);

multicast_send_data(dummyData,totLen);

}

  }

void

multicast_init(void)

{

      multicastIp.addr = ipaddr_addr(multicast_ip);

multiAppPcb = udp_new_ip_type(IPADDR_TYPE_ANY);

if (multiAppPcb != NULL) {

    err_t err;

    err = udp_bind(multiAppPcb, IP_ADDR_ANY, MULTICAST_PORT);

    if (err == ERR_OK) {

#if LWIP_IGMP

err_t iret =

igmp_joingroup(IP_ADDR_ANY,(const struct ip4_addr *)(&multicastIp));

if(iret){

initErr = 1 ;

return ;

}

#endif // LWIP_IGMP

udp_set_multicast_netif_addr(multiAppPcb,(const struct ip4_addr *)(&multicastIp));

udp_set_multicast_ttl(multiAppPcb,5);

udp_recv(multiAppPcb, multicast_recv, multiAppPcb);

    } else {

      /* abort? output diagnostic? */

initErr = 1;

    }

  } else {

    /* abort? output diagnostic? */

initErr = 1;

  }

}

int multicast_send_data(const char* buff,uint16_t len )

{

err_t err;

  if (initErr == 1)

return 1 ;

struct pbuf *p = pbuf_alloc(PBUF_RAW,len,PBUF_RAM);

int ret  = 0 ; 

if(p == NULL)

return 1 ;

if(pbuf_take(p,buff,len) != ERR_OK)

{

ret = 1 ; 

goto udp_app_send_end;

}

err = udp_sendto(multiAppPcb, p, &multicastIp, MULTICAST_PORT) ;

if(err != ERR_OK)

ret = 1 ;

udp_app_send_end:

pbuf_free(p);

return ret ;

}

static void

multicast_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p,

                 const ip_addr_t *addr, u16_t port)

{

  LWIP_UNUSED_ARG(arg);

  if (p != NULL) {

    /* send received packet back to sender */

//udp_sendto(upcb, p, addr, port);

  char* recv_buff = (char*) mem_malloc(p->tot_len);

  if(recv_buff){

  extract_payload(p,recv_buff);

  multicast_recv_callback(recv_buff,p->tot_len);

  }else{

  multicast_recv_callback(NULL,p->tot_len);

  }

    /* free the pbuf */

    pbuf_free(p);

  }

}

void  extract_payload(struct pbuf *p,char *payload)

{

struct pbuf *q = p ;

while(q)

{

for(int i = 0  ; i < q->len ; i++ )

{

payload[i] =((char*)(q->payload))[i];

}

q = p->next;

}

}

void multicast_recv_callback(char* buff, int len )

{

if(buff != NULL){

}else{

// invalid

}

}

-----------------------------------------------------------------------------------------------------------

Best Regards,

Amr Elsayed.

RA @ E-JUST.

Founder & Engineer @ DIY-Life.

address@hidden

+201223240852.

 

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