Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 675 insertions, 0 deletions

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
new file mode 100644
index 0000000000..5e9c815665
--- /dev/null
+++ b/net/ipv4/ip_input.c
@@ -0,0 +1,675 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		The Internet Protocol (IP) module.
+ *
+ * Authors:	Ross Biro
+ *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ *		Donald Becker, <becker@super.org>
+ *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
+ *		Richard Underwood
+ *		Stefan Becker, <stefanb@yello.ping.de>
+ *		Jorge Cwik, <jorge@laser.satlink.net>
+ *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
+ *
+ * Fixes:
+ *		Alan Cox	:	Commented a couple of minor bits of surplus code
+ *		Alan Cox	:	Undefining IP_FORWARD doesn't include the code
+ *					(just stops a compiler warning).
+ *		Alan Cox	:	Frames with >=MAX_ROUTE record routes, strict routes or loose routes
+ *					are junked rather than corrupting things.
+ *		Alan Cox	:	Frames to bad broadcast subnets are dumped
+ *					We used to process them non broadcast and
+ *					boy could that cause havoc.
+ *		Alan Cox	:	ip_forward sets the free flag on the
+ *					new frame it queues. Still crap because
+ *					it copies the frame but at least it
+ *					doesn't eat memory too.
+ *		Alan Cox	:	Generic queue code and memory fixes.
+ *		Fred Van Kempen :	IP fragment support (borrowed from NET2E)
+ *		Gerhard Koerting:	Forward fragmented frames correctly.
+ *		Gerhard Koerting: 	Fixes to my fix of the above 8-).
+ *		Gerhard Koerting:	IP interface addressing fix.
+ *		Linus Torvalds	:	More robustness checks
+ *		Alan Cox	:	Even more checks: Still not as robust as it ought to be
+ *		Alan Cox	:	Save IP header pointer for later
+ *		Alan Cox	:	ip option setting
+ *		Alan Cox	:	Use ip_tos/ip_ttl settings
+ *		Alan Cox	:	Fragmentation bogosity removed
+ *					(Thanks to Mark.Bush@prg.ox.ac.uk)
+ *		Dmitry Gorodchanin :	Send of a raw packet crash fix.
+ *		Alan Cox	:	Silly ip bug when an overlength
+ *					fragment turns up. Now frees the
+ *					queue.
+ *		Linus Torvalds/ :	Memory leakage on fragmentation
+ *		Alan Cox	:	handling.
+ *		Gerhard Koerting:	Forwarding uses IP priority hints
+ *		Teemu Rantanen	:	Fragment problems.
+ *		Alan Cox	:	General cleanup, comments and reformat
+ *		Alan Cox	:	SNMP statistics
+ *		Alan Cox	:	BSD address rule semantics. Also see
+ *					UDP as there is a nasty checksum issue
+ *					if you do things the wrong way.
+ *		Alan Cox	:	Always defrag, moved IP_FORWARD to the config.in file
+ *		Alan Cox	: 	IP options adjust sk->priority.
+ *		Pedro Roque	:	Fix mtu/length error in ip_forward.
+ *		Alan Cox	:	Avoid ip_chk_addr when possible.
+ *	Richard Underwood	:	IP multicasting.
+ *		Alan Cox	:	Cleaned up multicast handlers.
+ *		Alan Cox	:	RAW sockets demultiplex in the BSD style.
+ *		Gunther Mayer	:	Fix the SNMP reporting typo
+ *		Alan Cox	:	Always in group 224.0.0.1
+ *	Pauline Middelink	:	Fast ip_checksum update when forwarding
+ *					Masquerading support.
+ *		Alan Cox	:	Multicast loopback error for 224.0.0.1
+ *		Alan Cox	:	IP_MULTICAST_LOOP option.
+ *		Alan Cox	:	Use notifiers.
+ *		Bjorn Ekwall	:	Removed ip_csum (from slhc.c too)
+ *		Bjorn Ekwall	:	Moved ip_fast_csum to ip.h (inline!)
+ *		Stefan Becker   :       Send out ICMP HOST REDIRECT
+ *	Arnt Gulbrandsen	:	ip_build_xmit
+ *		Alan Cox	:	Per socket routing cache
+ *		Alan Cox	:	Fixed routing cache, added header cache.
+ *		Alan Cox	:	Loopback didn't work right in original ip_build_xmit - fixed it.
+ *		Alan Cox	:	Only send ICMP_REDIRECT if src/dest are the same net.
+ *		Alan Cox	:	Incoming IP option handling.
+ *		Alan Cox	:	Set saddr on raw output frames as per BSD.
+ *		Alan Cox	:	Stopped broadcast source route explosions.
+ *		Alan Cox	:	Can disable source routing
+ *		Takeshi Sone    :	Masquerading didn't work.
+ *	Dave Bonn,Alan Cox	:	Faster IP forwarding whenever possible.
+ *		Alan Cox	:	Memory leaks, tramples, misc debugging.
+ *		Alan Cox	:	Fixed multicast (by popular demand 8))
+ *		Alan Cox	:	Fixed forwarding (by even more popular demand 8))
+ *		Alan Cox	:	Fixed SNMP statistics [I think]
+ *	Gerhard Koerting	:	IP fragmentation forwarding fix
+ *		Alan Cox	:	Device lock against page fault.
+ *		Alan Cox	:	IP_HDRINCL facility.
+ *	Werner Almesberger	:	Zero fragment bug
+ *		Alan Cox	:	RAW IP frame length bug
+ *		Alan Cox	:	Outgoing firewall on build_xmit
+ *		A.N.Kuznetsov	:	IP_OPTIONS support throughout the kernel
+ *		Alan Cox	:	Multicast routing hooks
+ *		Jos Vos		:	Do accounting *before* call_in_firewall
+ *	Willy Konynenberg	:	Transparent proxying support
+ *
+ * To Fix:
+ *		IP fragmentation wants rewriting cleanly. The RFC815 algorithm is much more efficient
+ *		and could be made very efficient with the addition of some virtual memory hacks to permit
+ *		the allocation of a buffer that can then be 'grown' by twiddling page tables.
+ *		Output fragmentation wants updating along with the buffer management to use a single
+ *		interleaved copy algorithm so that fragmenting has a one copy overhead. Actual packet
+ *		output should probably do its own fragmentation at the UDP/RAW layer. TCP shouldn't cause
+ *		fragmentation anyway.
+ */
+
+#define pr_fmt(fmt) "IPv4: " fmt
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/inetdevice.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/indirect_call_wrapper.h>
+
+#include <net/snmp.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <net/route.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/arp.h>
+#include <net/icmp.h>
+#include <net/raw.h>
+#include <net/checksum.h>
+#include <net/inet_ecn.h>
+#include <linux/netfilter_ipv4.h>
+#include <net/xfrm.h>
+#include <linux/mroute.h>
+#include <linux/netlink.h>
+#include <net/dst_metadata.h>
+
+/*
+ *	Process Router Attention IP option (RFC 2113)
+ */
+bool ip_call_ra_chain(struct sk_buff *skb)
+{
+	struct ip_ra_chain *ra;
+	u8 protocol = ip_hdr(skb)->protocol;
+	struct sock *last = NULL;
+	struct net_device *dev = skb->dev;
+	struct net *net = dev_net(dev);
+
+	for (ra = rcu_dereference(net->ipv4.ra_chain); ra; ra = rcu_dereference(ra->next)) {
+		struct sock *sk = ra->sk;
+
+		/* If socket is bound to an interface, only report
+		 * the packet if it came  from that interface.
+		 */
+		if (sk && inet_sk(sk)->inet_num == protocol &&
+		    (!sk->sk_bound_dev_if ||
+		     sk->sk_bound_dev_if == dev->ifindex)) {
+			if (ip_is_fragment(ip_hdr(skb))) {
+				if (ip_defrag(net, skb, IP_DEFRAG_CALL_RA_CHAIN))
+					return true;
+			}
+			if (last) {
+				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
+				if (skb2)
+					raw_rcv(last, skb2);
+			}
+			last = sk;
+		}
+	}
+
+	if (last) {
+		raw_rcv(last, skb);
+		return true;
+	}
+	return false;
+}
+
+INDIRECT_CALLABLE_DECLARE(int udp_rcv(struct sk_buff *));
+INDIRECT_CALLABLE_DECLARE(int tcp_v4_rcv(struct sk_buff *));
+void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int protocol)
+{
+	const struct net_protocol *ipprot;
+	int raw, ret;
+
+resubmit:
+	raw = raw_local_deliver(skb, protocol);
+
+	ipprot = rcu_dereference(inet_protos[protocol]);
+	if (ipprot) {
+		if (!ipprot->no_policy) {
+			if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+				kfree_skb_reason(skb,
+						 SKB_DROP_REASON_XFRM_POLICY);
+				return;
+			}
+			nf_reset_ct(skb);
+		}
+		ret = INDIRECT_CALL_2(ipprot->handler, tcp_v4_rcv, udp_rcv,
+				      skb);
+		if (ret < 0) {
+			protocol = -ret;
+			goto resubmit;
+		}
+		__IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS);
+	} else {
+		if (!raw) {
+			if (xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+				__IP_INC_STATS(net, IPSTATS_MIB_INUNKNOWNPROTOS);
+				icmp_send(skb, ICMP_DEST_UNREACH,
+					  ICMP_PROT_UNREACH, 0);
+			}
+			kfree_skb_reason(skb, SKB_DROP_REASON_IP_NOPROTO);
+		} else {
+			__IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS);
+			consume_skb(skb);
+		}
+	}
+}
+
+static int ip_local_deliver_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	skb_clear_delivery_time(skb);
+	__skb_pull(skb, skb_network_header_len(skb));
+
+	rcu_read_lock();
+	ip_protocol_deliver_rcu(net, skb, ip_hdr(skb)->protocol);
+	rcu_read_unlock();
+
+	return 0;
+}
+
+/*
+ * 	Deliver IP Packets to the higher protocol layers.
+ */
+int ip_local_deliver(struct sk_buff *skb)
+{
+	/*
+	 *	Reassemble IP fragments.
+	 */
+	struct net *net = dev_net(skb->dev);
+
+	if (ip_is_fragment(ip_hdr(skb))) {
+		if (ip_defrag(net, skb, IP_DEFRAG_LOCAL_DELIVER))
+			return 0;
+	}
+
+	return NF_HOOK(NFPROTO_IPV4, NF_INET_LOCAL_IN,
+		       net, NULL, skb, skb->dev, NULL,
+		       ip_local_deliver_finish);
+}
+EXPORT_SYMBOL(ip_local_deliver);
+
+static inline bool ip_rcv_options(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ip_options *opt;
+	const struct iphdr *iph;
+
+	/* It looks as overkill, because not all
+	   IP options require packet mangling.
+	   But it is the easiest for now, especially taking
+	   into account that combination of IP options
+	   and running sniffer is extremely rare condition.
+					      --ANK (980813)
+	*/
+	if (skb_cow(skb, skb_headroom(skb))) {
+		__IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INDISCARDS);
+		goto drop;
+	}
+
+	iph = ip_hdr(skb);
+	opt = &(IPCB(skb)->opt);
+	opt->optlen = iph->ihl*4 - sizeof(struct iphdr);
+
+	if (ip_options_compile(dev_net(dev), opt, skb)) {
+		__IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INHDRERRORS);
+		goto drop;
+	}
+
+	if (unlikely(opt->srr)) {
+		struct in_device *in_dev = __in_dev_get_rcu(dev);
+
+		if (in_dev) {
+			if (!IN_DEV_SOURCE_ROUTE(in_dev)) {
+				if (IN_DEV_LOG_MARTIANS(in_dev))
+					net_info_ratelimited("source route option %pI4 -> %pI4\n",
+							     &iph->saddr,
+							     &iph->daddr);
+				goto drop;
+			}
+		}
+
+		if (ip_options_rcv_srr(skb, dev))
+			goto drop;
+	}
+
+	return false;
+drop:
+	return true;
+}
+
+static bool ip_can_use_hint(const struct sk_buff *skb, const struct iphdr *iph,
+			    const struct sk_buff *hint)
+{
+	return hint && !skb_dst(skb) && ip_hdr(hint)->daddr == iph->daddr &&
+	       ip_hdr(hint)->tos == iph->tos;
+}
+
+int tcp_v4_early_demux(struct sk_buff *skb);
+int udp_v4_early_demux(struct sk_buff *skb);
+static int ip_rcv_finish_core(struct net *net, struct sock *sk,
+			      struct sk_buff *skb, struct net_device *dev,
+			      const struct sk_buff *hint)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	int err, drop_reason;
+	struct rtable *rt;
+
+	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
+
+	if (ip_can_use_hint(skb, iph, hint)) {
+		err = ip_route_use_hint(skb, iph->daddr, iph->saddr, iph->tos,
+					dev, hint);
+		if (unlikely(err))
+			goto drop_error;
+	}
+
+	if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) &&
+	    !skb_dst(skb) &&
+	    !skb->sk &&
+	    !ip_is_fragment(iph)) {
+		switch (iph->protocol) {
+		case IPPROTO_TCP:
+			if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux)) {
+				tcp_v4_early_demux(skb);
+
+				/* must reload iph, skb->head might have changed */
+				iph = ip_hdr(skb);
+			}
+			break;
+		case IPPROTO_UDP:
+			if (READ_ONCE(net->ipv4.sysctl_udp_early_demux)) {
+				err = udp_v4_early_demux(skb);
+				if (unlikely(err))
+					goto drop_error;
+
+				/* must reload iph, skb->head might have changed */
+				iph = ip_hdr(skb);
+			}
+			break;
+		}
+	}
+
+	/*
+	 *	Initialise the virtual path cache for the packet. It describes
+	 *	how the packet travels inside Linux networking.
+	 */
+	if (!skb_valid_dst(skb)) {
+		err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
+					   iph->tos, dev);
+		if (unlikely(err))
+			goto drop_error;
+	} else {
+		struct in_device *in_dev = __in_dev_get_rcu(dev);
+
+		if (in_dev && IN_DEV_ORCONF(in_dev, NOPOLICY))
+			IPCB(skb)->flags |= IPSKB_NOPOLICY;
+	}
+
+#ifdef CONFIG_IP_ROUTE_CLASSID
+	if (unlikely(skb_dst(skb)->tclassid)) {
+		struct ip_rt_acct *st = this_cpu_ptr(ip_rt_acct);
+		u32 idx = skb_dst(skb)->tclassid;
+		st[idx&0xFF].o_packets++;
+		st[idx&0xFF].o_bytes += skb->len;
+		st[(idx>>16)&0xFF].i_packets++;
+		st[(idx>>16)&0xFF].i_bytes += skb->len;
+	}
+#endif
+
+	if (iph->ihl > 5 && ip_rcv_options(skb, dev))
+		goto drop;
+
+	rt = skb_rtable(skb);
+	if (rt->rt_type == RTN_MULTICAST) {
+		__IP_UPD_PO_STATS(net, IPSTATS_MIB_INMCAST, skb->len);
+	} else if (rt->rt_type == RTN_BROADCAST) {
+		__IP_UPD_PO_STATS(net, IPSTATS_MIB_INBCAST, skb->len);
+	} else if (skb->pkt_type == PACKET_BROADCAST ||
+		   skb->pkt_type == PACKET_MULTICAST) {
+		struct in_device *in_dev = __in_dev_get_rcu(dev);
+
+		/* RFC 1122 3.3.6:
+		 *
+		 *   When a host sends a datagram to a link-layer broadcast
+		 *   address, the IP destination address MUST be a legal IP
+		 *   broadcast or IP multicast address.
+		 *
+		 *   A host SHOULD silently discard a datagram that is received
+		 *   via a link-layer broadcast (see Section 2.4) but does not
+		 *   specify an IP multicast or broadcast destination address.
+		 *
+		 * This doesn't explicitly say L2 *broadcast*, but broadcast is
+		 * in a way a form of multicast and the most common use case for
+		 * this is 802.11 protecting against cross-station spoofing (the
+		 * so-called "hole-196" attack) so do it for both.
+		 */
+		if (in_dev &&
+		    IN_DEV_ORCONF(in_dev, DROP_UNICAST_IN_L2_MULTICAST)) {
+			drop_reason = SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST;
+			goto drop;
+		}
+	}
+
+	return NET_RX_SUCCESS;
+
+drop:
+	kfree_skb_reason(skb, drop_reason);
+	return NET_RX_DROP;
+
+drop_error:
+	if (err == -EXDEV) {
+		drop_reason = SKB_DROP_REASON_IP_RPFILTER;
+		__NET_INC_STATS(net, LINUX_MIB_IPRPFILTER);
+	}
+	goto drop;
+}
+
+static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct net_device *dev = skb->dev;
+	int ret;
+
+	/* if ingress device is enslaved to an L3 master device pass the
+	 * skb to its handler for processing
+	 */
+	skb = l3mdev_ip_rcv(skb);
+	if (!skb)
+		return NET_RX_SUCCESS;
+
+	ret = ip_rcv_finish_core(net, sk, skb, dev, NULL);
+	if (ret != NET_RX_DROP)
+		ret = dst_input(skb);
+	return ret;
+}
+
+/*
+ * 	Main IP Receive routine.
+ */
+static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)
+{
+	const struct iphdr *iph;
+	int drop_reason;
+	u32 len;
+
+	/* When the interface is in promisc. mode, drop all the crap
+	 * that it receives, do not try to analyse it.
+	 */
+	if (skb->pkt_type == PACKET_OTHERHOST) {
+		dev_core_stats_rx_otherhost_dropped_inc(skb->dev);
+		drop_reason = SKB_DROP_REASON_OTHERHOST;
+		goto drop;
+	}
+
+	__IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len);
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb) {
+		__IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
+		goto out;
+	}
+
+	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
+	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+		goto inhdr_error;
+
+	iph = ip_hdr(skb);
+
+	/*
+	 *	RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum.
+	 *
+	 *	Is the datagram acceptable?
+	 *
+	 *	1.	Length at least the size of an ip header
+	 *	2.	Version of 4
+	 *	3.	Checksums correctly. [Speed optimisation for later, skip loopback checksums]
+	 *	4.	Doesn't have a bogus length
+	 */
+
+	if (iph->ihl < 5 || iph->version != 4)
+		goto inhdr_error;
+
+	BUILD_BUG_ON(IPSTATS_MIB_ECT1PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_1);
+	BUILD_BUG_ON(IPSTATS_MIB_ECT0PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_0);
+	BUILD_BUG_ON(IPSTATS_MIB_CEPKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_CE);
+	__IP_ADD_STATS(net,
+		       IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK),
+		       max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
+
+	if (!pskb_may_pull(skb, iph->ihl*4))
+		goto inhdr_error;
+
+	iph = ip_hdr(skb);
+
+	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
+		goto csum_error;
+
+	len = iph_totlen(skb, iph);
+	if (skb->len < len) {
+		drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
+		__IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
+		goto drop;
+	} else if (len < (iph->ihl*4))
+		goto inhdr_error;
+
+	/* Our transport medium may have padded the buffer out. Now we know it
+	 * is IP we can trim to the true length of the frame.
+	 * Note this now means skb->len holds ntohs(iph->tot_len).
+	 */
+	if (pskb_trim_rcsum(skb, len)) {
+		__IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
+		goto drop;
+	}
+
+	iph = ip_hdr(skb);
+	skb->transport_header = skb->network_header + iph->ihl*4;
+
+	/* Remove any debris in the socket control block */
+	memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+	IPCB(skb)->iif = skb->skb_iif;
+
+	/* Must drop socket now because of tproxy. */
+	if (!skb_sk_is_prefetched(skb))
+		skb_orphan(skb);
+
+	return skb;
+
+csum_error:
+	drop_reason = SKB_DROP_REASON_IP_CSUM;
+	__IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
+inhdr_error:
+	if (drop_reason == SKB_DROP_REASON_NOT_SPECIFIED)
+		drop_reason = SKB_DROP_REASON_IP_INHDR;
+	__IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
+drop:
+	kfree_skb_reason(skb, drop_reason);
+out:
+	return NULL;
+}
+
+/*
+ * IP receive entry point
+ */
+int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
+	   struct net_device *orig_dev)
+{
+	struct net *net = dev_net(dev);
+
+	skb = ip_rcv_core(skb, net);
+	if (skb == NULL)
+		return NET_RX_DROP;
+
+	return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
+		       net, NULL, skb, dev, NULL,
+		       ip_rcv_finish);
+}
+
+static void ip_sublist_rcv_finish(struct list_head *head)
+{
+	struct sk_buff *skb, *next;
+
+	list_for_each_entry_safe(skb, next, head, list) {
+		skb_list_del_init(skb);
+		dst_input(skb);
+	}
+}
+
+static struct sk_buff *ip_extract_route_hint(const struct net *net,
+					     struct sk_buff *skb, int rt_type)
+{
+	if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST ||
+	    IPCB(skb)->flags & IPSKB_MULTIPATH)
+		return NULL;
+
+	return skb;
+}
+
+static void ip_list_rcv_finish(struct net *net, struct sock *sk,
+			       struct list_head *head)
+{
+	struct sk_buff *skb, *next, *hint = NULL;
+	struct dst_entry *curr_dst = NULL;
+	struct list_head sublist;
+
+	INIT_LIST_HEAD(&sublist);
+	list_for_each_entry_safe(skb, next, head, list) {
+		struct net_device *dev = skb->dev;
+		struct dst_entry *dst;
+
+		skb_list_del_init(skb);
+		/* if ingress device is enslaved to an L3 master device pass the
+		 * skb to its handler for processing
+		 */
+		skb = l3mdev_ip_rcv(skb);
+		if (!skb)
+			continue;
+		if (ip_rcv_finish_core(net, sk, skb, dev, hint) == NET_RX_DROP)
+			continue;
+
+		dst = skb_dst(skb);
+		if (curr_dst != dst) {
+			hint = ip_extract_route_hint(net, skb,
+					       ((struct rtable *)dst)->rt_type);
+
+			/* dispatch old sublist */
+			if (!list_empty(&sublist))
+				ip_sublist_rcv_finish(&sublist);
+			/* start new sublist */
+			INIT_LIST_HEAD(&sublist);
+			curr_dst = dst;
+		}
+		list_add_tail(&skb->list, &sublist);
+	}
+	/* dispatch final sublist */
+	ip_sublist_rcv_finish(&sublist);
+}
+
+static void ip_sublist_rcv(struct list_head *head, struct net_device *dev,
+			   struct net *net)
+{
+	NF_HOOK_LIST(NFPROTO_IPV4, NF_INET_PRE_ROUTING, net, NULL,
+		     head, dev, NULL, ip_rcv_finish);
+	ip_list_rcv_finish(net, NULL, head);
+}
+
+/* Receive a list of IP packets */
+void ip_list_rcv(struct list_head *head, struct packet_type *pt,
+		 struct net_device *orig_dev)
+{
+	struct net_device *curr_dev = NULL;
+	struct net *curr_net = NULL;
+	struct sk_buff *skb, *next;
+	struct list_head sublist;
+
+	INIT_LIST_HEAD(&sublist);
+	list_for_each_entry_safe(skb, next, head, list) {
+		struct net_device *dev = skb->dev;
+		struct net *net = dev_net(dev);
+
+		skb_list_del_init(skb);
+		skb = ip_rcv_core(skb, net);
+		if (skb == NULL)
+			continue;
+
+		if (curr_dev != dev || curr_net != net) {
+			/* dispatch old sublist */
+			if (!list_empty(&sublist))
+				ip_sublist_rcv(&sublist, curr_dev, curr_net);
+			/* start new sublist */
+			INIT_LIST_HEAD(&sublist);
+			curr_dev = dev;
+			curr_net = net;
+		}
+		list_add_tail(&skb->list, &sublist);
+	}
+	/* dispatch final sublist */
+	if (!list_empty(&sublist))
+		ip_sublist_rcv(&sublist, curr_dev, curr_net);
+}