303 	struct pptp_gre_header *header;  in pptp_rcv_core()  local
311 	header = (struct pptp_gre_header *)(skb->data);  in pptp_rcv_core()
312 	headersize  = sizeof(*header);  in pptp_rcv_core()
315 	if (PPTP_GRE_IS_A(header->ver)) {  in pptp_rcv_core()
320 		header = (struct pptp_gre_header *)(skb->data);  in pptp_rcv_core()
323 		ack = PPTP_GRE_IS_S(header->flags) ? header->ack : header->seq;  in pptp_rcv_core()
333 		headersize -= sizeof(header->ack);  in pptp_rcv_core()
336 	if (!PPTP_GRE_IS_S(header->flags))  in pptp_rcv_core()
339 	payload_len = ntohs(header->payload_len);  in pptp_rcv_core()
340 	seq         = ntohl(header->seq);  in pptp_rcv_core()
384 	struct pptp_gre_header *header;  in pptp_rcv()  local
395 	header = (struct pptp_gre_header *)skb->data;  in pptp_rcv()
397 	if (ntohs(header->protocol) != PPTP_GRE_PROTO || /* PPTP-GRE protocol for PPTP */  in pptp_rcv()
398 		PPTP_GRE_IS_C(header->flags) ||                /* flag C should be clear */  in pptp_rcv()
399 		PPTP_GRE_IS_R(header->flags) ||                /* flag R should be clear */  in pptp_rcv()
400 		!PPTP_GRE_IS_K(header->flags) ||               /* flag K should be set */  in pptp_rcv()
401 		(header->flags&0xF) != 0)                      /* routing and recursion ctrl = 0 */  in pptp_rcv()
405 	po = lookup_chan(htons(header->call_id), iph->saddr);  in pptp_rcv()