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.
153 	u8 protocol = ip_hdr(skb)->protocol;  in ip_call_ra_chain()
155 	struct net_device *dev = skb->dev;  in ip_call_ra_chain()
158 	for (ra = rcu_dereference(net->ipv4.ra_chain); ra; ra = rcu_dereference(ra->next)) {  in ip_call_ra_chain()
159 		struct sock *sk = ra->sk;  in ip_call_ra_chain()
164 		if (sk && inet_sk(sk)->inet_num == protocol &&  in ip_call_ra_chain()
165 		    (!sk->sk_bound_dev_if ||  in ip_call_ra_chain()
166 		     sk->sk_bound_dev_if == dev->ifindex)) {  in ip_call_ra_chain()
199 		if (!ipprot->no_policy) {  in ip_protocol_deliver_rcu()
207 		ret = INDIRECT_CALL_2(ipprot->handler, tcp_v4_rcv, udp_rcv,  in ip_protocol_deliver_rcu()
210 			protocol = -ret;  in ip_protocol_deliver_rcu()
241 	ip_protocol_deliver_rcu(net, skb, ip_hdr(skb)->protocol);  in ip_local_deliver_finish()
255 	struct net *net = dev_net(skb->dev);  in ip_local_deliver()
263 		       net, NULL, skb, skb->dev, NULL,  in ip_local_deliver()
279 					      --ANK (980813)  in ip_rcv_options()
287 	opt = &(IPCB(skb)->opt);  in ip_rcv_options()
288 	opt->optlen = iph->ihl*4 - sizeof(struct iphdr);  in ip_rcv_options()
295 	if (unlikely(opt->srr)) {  in ip_rcv_options()
301 					net_info_ratelimited("source route option %pI4 -> %pI4\n",  in ip_rcv_options()
302 							     &iph->saddr,  in ip_rcv_options()
303 							     &iph->daddr);  in ip_rcv_options()
318 	return hint && !skb_dst(skb) && ip_hdr(hint)->daddr == iph->daddr &&  in ip_can_use_hint()
319 	       ip_hdr(hint)->tos == iph->tos;  in ip_can_use_hint()
331 		drop_reason = ip_route_use_hint(skb, iph->daddr, iph->saddr,  in ip_rcv_finish_core()
337 	if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) &&  in ip_rcv_finish_core()
339 	    !skb->sk &&  in ip_rcv_finish_core()
341 		switch (iph->protocol) {  in ip_rcv_finish_core()
343 			if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux)) {  in ip_rcv_finish_core()
346 				/* must reload iph, skb->head might have changed */  in ip_rcv_finish_core()
351 			if (READ_ONCE(net->ipv4.sysctl_udp_early_demux)) {  in ip_rcv_finish_core()
356 				/* must reload iph, skb->head might have changed */  in ip_rcv_finish_core()
368 		drop_reason = ip_route_input_noref(skb, iph->daddr, iph->saddr,  in ip_rcv_finish_core()
376 			IPCB(skb)->flags |= IPSKB_NOPOLICY;  in ip_rcv_finish_core()
380 	if (unlikely(skb_dst(skb)->tclassid)) {  in ip_rcv_finish_core()
382 		u32 idx = skb_dst(skb)->tclassid;  in ip_rcv_finish_core()
384 		st[idx&0xFF].o_bytes += skb->len;  in ip_rcv_finish_core()
386 		st[(idx>>16)&0xFF].i_bytes += skb->len;  in ip_rcv_finish_core()
390 	if (iph->ihl > 5) {  in ip_rcv_finish_core()
397 	if (rt->rt_type == RTN_MULTICAST) {  in ip_rcv_finish_core()
398 		__IP_UPD_PO_STATS(net, IPSTATS_MIB_INMCAST, skb->len);  in ip_rcv_finish_core()
399 	} else if (rt->rt_type == RTN_BROADCAST) {  in ip_rcv_finish_core()
400 		__IP_UPD_PO_STATS(net, IPSTATS_MIB_INBCAST, skb->len);  in ip_rcv_finish_core()
401 	} else if (skb->pkt_type == PACKET_BROADCAST ||  in ip_rcv_finish_core()
402 		   skb->pkt_type == PACKET_MULTICAST) {  in ip_rcv_finish_core()
407 		 *   When a host sends a datagram to a link-layer broadcast  in ip_rcv_finish_core()
412 		 *   via a link-layer broadcast (see Section 2.4) but does not  in ip_rcv_finish_core()
417 		 * this is 802.11 protecting against cross-station spoofing (the  in ip_rcv_finish_core()
418 		 * so-called "hole-196" attack) so do it for both.  in ip_rcv_finish_core()
441 	struct net_device *dev = skb->dev;  in ip_rcv_finish()
469 	if (skb->pkt_type == PACKET_OTHERHOST) {  in ip_rcv_core()
470 		dev_core_stats_rx_otherhost_dropped_inc(skb->dev);  in ip_rcv_core()
475 	__IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len);  in ip_rcv_core()
500 	if (iph->ihl < 5 || iph->version != 4)  in ip_rcv_core()
507 		       IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK),  in ip_rcv_core()
508 		       max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));  in ip_rcv_core()
510 	if (!pskb_may_pull(skb, iph->ihl*4))  in ip_rcv_core()
515 	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))  in ip_rcv_core()
519 	if (skb->len < len) {  in ip_rcv_core()
523 	} else if (len < (iph->ihl*4))  in ip_rcv_core()
528 	 * Note this now means skb->len holds ntohs(iph->tot_len).  in ip_rcv_core()
536 	skb->transport_header = skb->network_header + iph->ihl*4;  in ip_rcv_core()
540 	IPCB(skb)->iif = skb->skb_iif;  in ip_rcv_core()
594 	    ipv4_is_lbcast(iph->daddr) ||  in ip_extract_route_hint()
595 	    ipv4_is_zeronet(iph->daddr) ||  in ip_extract_route_hint()
596 	    IPCB(skb)->flags & IPSKB_MULTIPATH)  in ip_extract_route_hint()
609 		struct net_device *dev = skb->dev;  in ip_list_rcv_finish()
633 		list_add_tail(&skb->list, &sublist);  in ip_list_rcv_finish()
657 		struct net_device *dev = skb->dev;  in ip_list_rcv()
674 		list_add_tail(&skb->list, &sublist);  in ip_list_rcv()