I am coding apps transfer file with LKSCTP. With server receiver file. I 
use recvmsg(sk,&inmessage,0). And I want get infomation header of this 
packet, but I check inmessage. inmessage.msg_controllen=0, and 
inmessage.msg_flags=136. What's 136. In client I just send flags=0. And 
msg_control, msg_controllen with full infomation.
And cmsg = CMSG_FIRSTHDR(&inmessage); always return NULL so I can't 
write data to file.
Please help me.
I attacth code send_file recv_file. I have checked client. It's ok. But 
I don't know why infomation header is NULL.