Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 718 insertions, 0 deletions

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
new file mode 100644
index 000000000..986017875
--- /dev/null
+++ b/net/ipv4/ip_input.c
@@ -0,0 +1,718 @@
+// 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>
+#include <net/udp.h>
+#include <net/tcp.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)
+{
+	if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
+		__IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
+		kfree_skb_reason(skb, SKB_DROP_REASON_NOMEM);
+		return 0;
+	}
+
+	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 enum skb_drop_reason
+ip_rcv_options(struct sk_buff *skb, struct net_device *dev)
+{
+	const struct iphdr *iph;
+	struct ip_options *opt;
+
+	/* 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);
+		return SKB_DROP_REASON_NOMEM;
+	}
+
+	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);
+		return SKB_DROP_REASON_IP_INHDR;
+	}
+
+	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);
+				return SKB_DROP_REASON_NOT_SPECIFIED;
+			}
+		}
+
+		if (ip_options_rcv_srr(skb, dev))
+			return SKB_DROP_REASON_NOT_SPECIFIED;
+	}
+
+	return SKB_NOT_DROPPED_YET;
+}
+
+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;
+}
+
+static int tcp_v4_early_demux(struct sk_buff *skb)
+{
+	struct net *net = dev_net_rcu(skb->dev);
+	const struct iphdr *iph;
+	const struct tcphdr *th;
+	struct sock *sk;
+
+	if (skb->pkt_type != PACKET_HOST)
+		return 0;
+
+	if (!pskb_may_pull(skb, skb_transport_offset(skb) +
+				sizeof(struct tcphdr)))
+		return 0;
+
+	iph = ip_hdr(skb);
+	th = tcp_hdr(skb);
+
+	if (th->doff < sizeof(struct tcphdr) / 4)
+		return 0;
+
+	sk = __inet_lookup_established(net, iph->saddr, th->source,
+				       iph->daddr, ntohs(th->dest),
+				       skb->skb_iif, inet_sdif(skb));
+	if (sk) {
+		skb->sk = sk;
+		skb->destructor = sock_edemux;
+		if (sk_fullsock(sk)) {
+			struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst);
+
+			if (dst)
+				dst = dst_check(dst, 0);
+			if (dst &&
+			    sk->sk_rx_dst_ifindex == skb->skb_iif)
+				skb_dst_set_noref(skb, dst);
+		}
+	}
+	return 0;
+}
+
+static int ip_rcv_finish_core(struct net *net,
+			      struct sk_buff *skb, struct net_device *dev,
+			      const struct sk_buff *hint)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	struct rtable *rt;
+	int drop_reason;
+
+	if (ip_can_use_hint(skb, iph, hint)) {
+		drop_reason = ip_route_use_hint(skb, iph->daddr, iph->saddr,
+						ip4h_dscp(iph), dev, hint);
+		if (unlikely(drop_reason))
+			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)) {
+				drop_reason = udp_v4_early_demux(skb);
+				if (unlikely(drop_reason))
+					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)) {
+		drop_reason = ip_route_input_noref(skb, iph->daddr, iph->saddr,
+						   ip4h_dscp(iph), dev);
+		if (unlikely(drop_reason))
+			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) {
+		drop_reason = ip_rcv_options(skb, dev);
+		if (drop_reason)
+			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 (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, 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)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+
+	if (fib4_has_custom_rules(net) ||
+	    ipv4_is_lbcast(iph->daddr) ||
+	    ipv4_is_zeronet(iph->daddr) ||
+	    IPCB(skb)->flags & IPSKB_MULTIPATH)
+		return NULL;
+
+	return skb;
+}
+
+static void ip_list_rcv_finish(struct net *net, struct list_head *head)
+{
+	struct sk_buff *skb, *next, *hint = NULL;
+	struct dst_entry *curr_dst = NULL;
+	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, skb, dev, hint) == NET_RX_DROP)
+			continue;
+
+		dst = skb_dst(skb);
+		if (curr_dst != dst) {
+			hint = ip_extract_route_hint(net, skb);
+
+			/* 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, 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;
+	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);
+}