1 // SPDX-License-Identifier: GPL-2.0-or-later
11  *		Donald Becker, <becker@super.org>
22  *		Alan Cox	:	Frames with >=MAX_ROUTE record routes, strict routes or loose routes
24  *		Alan Cox	:	Frames to bad broadcast subnets are dumped
33  *		Gerhard Koerting:	Forward fragmented frames correctly.
34  *		Gerhard Koerting: 	Fixes to my fix of the above 8-).
57  *		Alan Cox	: 	IP options adjust sk->priority.
76  *		Alan Cox	:	Loopback didn't work right in original ip_build_xmit - fixed it.
79  *		Alan Cox	:	Set saddr on raw output frames as per BSD.
151 	u8 protocol = ip_hdr(skb)->protocol;  in ip_call_ra_chain()
153 	struct net_device *dev = skb->dev;  in ip_call_ra_chain()
156 	for (ra = rcu_dereference(net->ipv4.ra_chain); ra; ra = rcu_dereference(ra->next)) {  in ip_call_ra_chain()
157 		struct sock *sk = ra->sk;  in ip_call_ra_chain()
162 		if (sk && inet_sk(sk)->inet_num == protocol &&  in ip_call_ra_chain()
163 		    (!sk->sk_bound_dev_if ||  in ip_call_ra_chain()
164 		     sk->sk_bound_dev_if == dev->ifindex)) {  in ip_call_ra_chain()
197 		if (!ipprot->no_policy) {  in ip_protocol_deliver_rcu()
205 		ret = INDIRECT_CALL_2(ipprot->handler, tcp_v4_rcv, udp_rcv,  in ip_protocol_deliver_rcu()
208 			protocol = -ret;  in ip_protocol_deliver_rcu()
233 	ip_protocol_deliver_rcu(net, skb, ip_hdr(skb)->protocol);  in ip_local_deliver_finish()
247 	struct net *net = dev_net(skb->dev);  in ip_local_deliver()
255 		       net, NULL, skb, skb->dev, NULL,  in ip_local_deliver()
270 					      --ANK (980813)  in ip_rcv_options()
278 	opt = &(IPCB(skb)->opt);  in ip_rcv_options()
279 	opt->optlen = iph->ihl*4 - sizeof(struct iphdr);  in ip_rcv_options()
286 	if (unlikely(opt->srr)) {  in ip_rcv_options()
292 					net_info_ratelimited("source route option %pI4 -> %pI4\n",  in ip_rcv_options()
293 							     &iph->saddr,  in ip_rcv_options()
294 							     &iph->daddr);  in ip_rcv_options()
311 	return hint && !skb_dst(skb) && ip_hdr(hint)->daddr == iph->daddr &&  in ip_can_use_hint()
312 	       ip_hdr(hint)->tos == iph->tos;  in ip_can_use_hint()
326 		drop_reason = ip_route_use_hint(skb, iph->daddr, iph->saddr,  in ip_rcv_finish_core()
333 	if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) &&  in ip_rcv_finish_core()
335 	    !skb->sk &&  in ip_rcv_finish_core()
337 		switch (iph->protocol) {  in ip_rcv_finish_core()
339 			if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux)) {  in ip_rcv_finish_core()
342 				/* must reload iph, skb->head might have changed */  in ip_rcv_finish_core()
347 			if (READ_ONCE(net->ipv4.sysctl_udp_early_demux)) {  in ip_rcv_finish_core()
352 				/* must reload iph, skb->head might have changed */  in ip_rcv_finish_core()
364 		drop_reason = ip_route_input_noref(skb, iph->daddr, iph->saddr,  in ip_rcv_finish_core()
373 			IPCB(skb)->flags |= IPSKB_NOPOLICY;  in ip_rcv_finish_core()
377 	if (unlikely(skb_dst(skb)->tclassid)) {  in ip_rcv_finish_core()
379 		u32 idx = skb_dst(skb)->tclassid;  in ip_rcv_finish_core()
381 		st[idx&0xFF].o_bytes += skb->len;  in ip_rcv_finish_core()
383 		st[(idx>>16)&0xFF].i_bytes += skb->len;  in ip_rcv_finish_core()
387 	if (iph->ihl > 5 && ip_rcv_options(skb, dev))  in ip_rcv_finish_core()
391 	if (rt->rt_type == RTN_MULTICAST) {  in ip_rcv_finish_core()
392 		__IP_UPD_PO_STATS(net, IPSTATS_MIB_INMCAST, skb->len);  in ip_rcv_finish_core()
393 	} else if (rt->rt_type == RTN_BROADCAST) {  in ip_rcv_finish_core()
394 		__IP_UPD_PO_STATS(net, IPSTATS_MIB_INBCAST, skb->len);  in ip_rcv_finish_core()
395 	} else if (skb->pkt_type == PACKET_BROADCAST ||  in ip_rcv_finish_core()
396 		   skb->pkt_type == PACKET_MULTICAST) {  in ip_rcv_finish_core()
401 		 *   When a host sends a datagram to a link-layer broadcast  in ip_rcv_finish_core()
406 		 *   via a link-layer broadcast (see Section 2.4) but does not  in ip_rcv_finish_core()
411 		 * this is 802.11 protecting against cross-station spoofing (the  in ip_rcv_finish_core()
412 		 * so-called "hole-196" attack) so do it for both.  in ip_rcv_finish_core()
435 	struct net_device *dev = skb->dev;  in ip_rcv_finish()
463 	if (skb->pkt_type == PACKET_OTHERHOST) {  in ip_rcv_core()
464 		dev_core_stats_rx_otherhost_dropped_inc(skb->dev);  in ip_rcv_core()
469 	__IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len);  in ip_rcv_core()
494 	if (iph->ihl < 5 || iph->version != 4)  in ip_rcv_core()
501 		       IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK),  in ip_rcv_core()
502 		       max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));  in ip_rcv_core()
504 	if (!pskb_may_pull(skb, iph->ihl*4))  in ip_rcv_core()
509 	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))  in ip_rcv_core()
513 	if (skb->len < len) {  in ip_rcv_core()
517 	} else if (len < (iph->ihl*4))  in ip_rcv_core()
522 	 * Note this now means skb->len holds ntohs(iph->tot_len).  in ip_rcv_core()
530 	skb->transport_header = skb->network_header + iph->ihl*4;  in ip_rcv_core()
534 	IPCB(skb)->iif = skb->skb_iif;  in ip_rcv_core()
586 	    IPCB(skb)->flags & IPSKB_MULTIPATH)  in ip_extract_route_hint()
599 		struct net_device *dev = skb->dev;  in ip_list_rcv_finish()
615 						     dst_rtable(dst)->rt_type);  in ip_list_rcv_finish()
624 		list_add_tail(&skb->list, &sublist);  in ip_list_rcv_finish()
648 		struct net_device *dev = skb->dev;  in ip_list_rcv()
665 		list_add_tail(&skb->list, &sublist);  in ip_list_rcv()