64 void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,  in gre_build_header()  argument
69 	skb_push(skb, hdr_len);  in gre_build_header()
71 	skb_reset_transport_header(skb);  in gre_build_header()
72 	greh = (struct gre_base_hdr *)skb->data;  in gre_build_header()
88 		    !(skb_shinfo(skb)->gso_type &  in gre_build_header()
91 			*(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,  in gre_build_header()
92 								 skb->len, 0));  in gre_build_header()
98 static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,  in parse_gre_header()  argument
105 	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))  in parse_gre_header()
108 	greh = (struct gre_base_hdr *)skb_transport_header(skb);  in parse_gre_header()
115 	if (!pskb_may_pull(skb, hdr_len))  in parse_gre_header()
118 	greh = (struct gre_base_hdr *)skb_transport_header(skb);  in parse_gre_header()
123 		if (skb_checksum_simple_validate(skb)) {  in parse_gre_header()
128 		skb_checksum_try_convert(skb, IPPROTO_GRE, 0,  in parse_gre_header()
154 			if (!pskb_may_pull(skb, hdr_len))  in parse_gre_header()
159 	return iptunnel_pull_header(skb, hdr_len, tpi->proto);  in parse_gre_header()
162 static int gre_cisco_rcv(struct sk_buff *skb)  in gre_cisco_rcv()  argument
169 	if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {  in gre_cisco_rcv()
171 		if (rt_is_output_route(skb_rtable(skb)))  in gre_cisco_rcv()
176 	if (parse_gre_header(skb, &tpi, &csum_err) < 0)  in gre_cisco_rcv()
187 		ret = proto->handler(skb, &tpi);  in gre_cisco_rcv()
195 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);  in gre_cisco_rcv()
197 	kfree_skb(skb);  in gre_cisco_rcv()
201 static void gre_cisco_err(struct sk_buff *skb, u32 info)  in gre_cisco_err()  argument
217 	const int type = icmp_hdr(skb)->type;  in gre_cisco_err()
218 	const int code = icmp_hdr(skb)->code;  in gre_cisco_err()
223 	if (parse_gre_header(skb, &tpi, &csum_err)) {  in gre_cisco_err()
229 		ipv4_update_pmtu(skb, dev_net(skb->dev), info,  in gre_cisco_err()
230 				skb->dev->ifindex, 0, IPPROTO_GRE, 0);  in gre_cisco_err()
234 		ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0,  in gre_cisco_err()
247 		if (proto->err_handler(skb, info, &tpi) == PACKET_RCVD)  in gre_cisco_err()
255 static int gre_rcv(struct sk_buff *skb)  in gre_rcv()  argument
261 	if (!pskb_may_pull(skb, 12))  in gre_rcv()
264 	ver = skb->data[1]&0x7f;  in gre_rcv()
272 	ret = proto->handler(skb);  in gre_rcv()
279 	kfree_skb(skb);  in gre_rcv()
283 static void gre_err(struct sk_buff *skb, u32 info)  in gre_err()  argument
286 	const struct iphdr *iph = (const struct iphdr *)skb->data;  in gre_err()
287 	u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;  in gre_err()
295 		proto->err_handler(skb, info);  in gre_err()