How to receive SACK of SCTP protocol in C - c

Question

I am using the following code to receive SCTP notifications. I am using Linux ubuntu 20.04.
Please could you help to intercept SACK_SCTP messages. Here you find attached my code to receive all possible notifications.
void *
receive_sacks(void *arg)
{
sockParamRcv_t paramsDest = *((sockParamRcv_t *) arg);
char buffer[100];
int ret;
int flags = 0;
struct sctp_sndrcvinfo info;
union sctp_notification *notification;
struct sctp_event_subscribe events;
socklen_t from_len = sizeof(paramsDest.servaddr.sin_addr);
// Set the events of interest for the socket
memset(&events, 0, sizeof(events));
events.sctp_data_io_event = 1;
events.sctp_association_event = 1;
events.sctp_adaptation_layer_event = 1;
events.sctp_send_failure_event = 1;
events.sctp_assoc_reset_event = 1;
events.sctp_stream_change_event = 1;
events.sctp_stream_reset_event = 1;
events.sctp_shutdown_event = 1;
events.sctp_send_failure_event = 1;
ret = setsockopt(paramsDest.sock, IPPROTO_SCTP, SCTP_EVENTS, &events, sizeof(events));
if (ret < 0) {
perror("setsockopt");
return 1;
}
while (1) {
ret = sctp_recvmsg(paramsDest.sock, buffer, sizeof(buffer), (struct sockaddr *) NULL, 0, &info, &flags);
if (ret < 0) {
perror("sctp_get_sndrcvinfo() failed");
close(paramsDest.sock);
exit(1);
}
printf("Received SCTP SACK message, %d\n", info.sinfo_flags);
printf("Received unexpected SCTP message type\n");
if (ret > 0) {
printf("flags : %d\n", flags);
printf("Received message: %s\n", buffer);
if (flags & MSG_NOTIFICATION) {
notification = (union sctp_notification *) buffer;
printf("flags : %d\n", flags);
}
}
}
return NULL;
}