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, 656 insertions, 0 deletions

diff --git a/include/net/udp.h b/include/net/udp.h
new file mode 100644
index 000000000..1fee17274
--- /dev/null
+++ b/include/net/udp.h
@@ -0,0 +1,656 @@
+/* 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.
+ *
+ *		Definitions for the UDP module.
+ *
+ * Version:	@(#)udp.h	1.0.2	05/07/93
+ *
+ * Authors:	Ross Biro
+ *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ *
+ * Fixes:
+ *		Alan Cox	: Turned on udp checksums. I don't want to
+ *				  chase 'memory corruption' bugs that aren't!
+ */
+#ifndef _UDP_H
+#define _UDP_H
+
+#include <linux/list.h>
+#include <linux/bug.h>
+#include <net/inet_sock.h>
+#include <net/gso.h>
+#include <net/sock.h>
+#include <net/snmp.h>
+#include <net/ip.h>
+#include <linux/ipv6.h>
+#include <linux/seq_file.h>
+#include <linux/poll.h>
+#include <linux/indirect_call_wrapper.h>
+#include <linux/math.h>
+
+/**
+ *	struct udp_skb_cb  -  UDP private variables
+ *
+ *	@header:      private variables used by IPv4/IPv6
+ */
+struct udp_skb_cb {
+	union {
+		struct inet_skb_parm	h4;
+#if IS_ENABLED(CONFIG_IPV6)
+		struct inet6_skb_parm	h6;
+#endif
+	} header;
+};
+#define UDP_SKB_CB(__skb)	((struct udp_skb_cb *)((__skb)->cb))
+
+/**
+ *	struct udp_hslot - UDP hash slot used by udp_table.hash/hash4
+ *
+ *	@head:	head of list of sockets
+ *	@nulls_head:	head of list of sockets, only used by hash4
+ *	@count:	number of sockets in 'head' list
+ *	@lock:	spinlock protecting changes to head/count
+ */
+struct udp_hslot {
+	union {
+		struct hlist_head	head;
+		/* hash4 uses hlist_nulls to avoid moving wrongly onto another
+		 * hlist, because rehash() can happen with lookup().
+		 */
+		struct hlist_nulls_head	nulls_head;
+	};
+	int			count;
+	spinlock_t		lock;
+} __aligned(2 * sizeof(long));
+
+/**
+ *	struct udp_hslot_main - UDP hash slot used by udp_table.hash2
+ *
+ *	@hslot:	basic hash slot
+ *	@hash4_cnt: number of sockets in hslot4 of the same
+ *		    (local port, local address)
+ */
+struct udp_hslot_main {
+	struct udp_hslot	hslot; /* must be the first member */
+#if !IS_ENABLED(CONFIG_BASE_SMALL)
+	u32			hash4_cnt;
+#endif
+} __aligned(2 * sizeof(long));
+#define UDP_HSLOT_MAIN(__hslot) ((struct udp_hslot_main *)(__hslot))
+
+/**
+ *	struct udp_table - UDP table
+ *
+ *	@hash:	hash table, sockets are hashed on (local port)
+ *	@hash2:	hash table, sockets are hashed on (local port, local address)
+ *	@hash4:	hash table, connected sockets are hashed on
+ *		(local port, local address, remote port, remote address)
+ *	@mask:	number of slots in hash tables, minus 1
+ *	@log:	log2(number of slots in hash table)
+ */
+struct udp_table {
+	struct udp_hslot	*hash;
+	struct udp_hslot_main	*hash2;
+#if !IS_ENABLED(CONFIG_BASE_SMALL)
+	struct udp_hslot	*hash4;
+#endif
+	unsigned int		mask;
+	unsigned int		log;
+};
+extern struct udp_table udp_table;
+
+static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
+					     const struct net *net,
+					     unsigned int num)
+{
+	return &table->hash[udp_hashfn(net, num, table->mask)];
+}
+
+/*
+ * For secondary hash, net_hash_mix() is performed before calling
+ * udp_hashslot2(), this explains difference with udp_hashslot()
+ */
+static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
+					      unsigned int hash)
+{
+	return &table->hash2[hash & table->mask].hslot;
+}
+
+#if IS_ENABLED(CONFIG_BASE_SMALL)
+static inline void udp_table_hash4_init(struct udp_table *table)
+{
+}
+
+static inline struct udp_hslot *udp_hashslot4(struct udp_table *table,
+					      unsigned int hash)
+{
+	BUILD_BUG();
+	return NULL;
+}
+
+static inline bool udp_hashed4(const struct sock *sk)
+{
+	return false;
+}
+
+static inline unsigned int udp_hash4_slot_size(void)
+{
+	return 0;
+}
+
+static inline bool udp_has_hash4(const struct udp_hslot *hslot2)
+{
+	return false;
+}
+
+static inline void udp_hash4_inc(struct udp_hslot *hslot2)
+{
+}
+
+static inline void udp_hash4_dec(struct udp_hslot *hslot2)
+{
+}
+#else /* !CONFIG_BASE_SMALL */
+
+/* Must be called with table->hash2 initialized */
+static inline void udp_table_hash4_init(struct udp_table *table)
+{
+	table->hash4 = (void *)(table->hash2 + (table->mask + 1));
+	for (int i = 0; i <= table->mask; i++) {
+		table->hash2[i].hash4_cnt = 0;
+
+		INIT_HLIST_NULLS_HEAD(&table->hash4[i].nulls_head, i);
+		table->hash4[i].count = 0;
+		spin_lock_init(&table->hash4[i].lock);
+	}
+}
+
+static inline struct udp_hslot *udp_hashslot4(struct udp_table *table,
+					      unsigned int hash)
+{
+	return &table->hash4[hash & table->mask];
+}
+
+static inline bool udp_hashed4(const struct sock *sk)
+{
+	return !hlist_nulls_unhashed(&udp_sk(sk)->udp_lrpa_node);
+}
+
+static inline unsigned int udp_hash4_slot_size(void)
+{
+	return sizeof(struct udp_hslot);
+}
+
+static inline bool udp_has_hash4(const struct udp_hslot *hslot2)
+{
+	return UDP_HSLOT_MAIN(hslot2)->hash4_cnt;
+}
+
+static inline void udp_hash4_inc(struct udp_hslot *hslot2)
+{
+	UDP_HSLOT_MAIN(hslot2)->hash4_cnt++;
+}
+
+static inline void udp_hash4_dec(struct udp_hslot *hslot2)
+{
+	UDP_HSLOT_MAIN(hslot2)->hash4_cnt--;
+}
+#endif /* CONFIG_BASE_SMALL */
+
+extern struct proto udp_prot;
+
+DECLARE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
+
+/* sysctl variables for udp */
+extern long sysctl_udp_mem[3];
+extern int sysctl_udp_rmem_min;
+extern int sysctl_udp_wmem_min;
+
+struct sk_buff;
+
+/*
+ *	Generic checksumming routines for UDP v4 and v6
+ */
+static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
+{
+	return __skb_checksum_complete(skb);
+}
+
+static inline int udp_lib_checksum_complete(struct sk_buff *skb)
+{
+	return !skb_csum_unnecessary(skb) &&
+		__udp_lib_checksum_complete(skb);
+}
+
+/**
+ * 	udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
+ * 	@sk: 	socket we are writing to
+ * 	@skb: 	sk_buff containing the filled-in UDP header
+ * 	        (checksum field must be zeroed out)
+ */
+static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
+{
+	__wsum csum = csum_partial(skb_transport_header(skb),
+				   sizeof(struct udphdr), 0);
+	skb_queue_walk(&sk->sk_write_queue, skb) {
+		csum = csum_add(csum, skb->csum);
+	}
+	return csum;
+}
+
+static inline __wsum udp_csum(struct sk_buff *skb)
+{
+	__wsum csum = csum_partial(skb_transport_header(skb),
+				   sizeof(struct udphdr), skb->csum);
+
+	for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
+		csum = csum_add(csum, skb->csum);
+	}
+	return csum;
+}
+
+static inline __sum16 udp_v4_check(int len, __be32 saddr,
+				   __be32 daddr, __wsum base)
+{
+	return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
+}
+
+void udp_set_csum(bool nocheck, struct sk_buff *skb,
+		  __be32 saddr, __be32 daddr, int len);
+
+static inline void udp_csum_pull_header(struct sk_buff *skb)
+{
+	if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
+		skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
+					 skb->csum);
+	skb_pull_rcsum(skb, sizeof(struct udphdr));
+}
+
+typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
+				     __be16 dport);
+
+void udp_v6_early_demux(struct sk_buff *skb);
+INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
+
+int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
+INDIRECT_CALLABLE_DECLARE(int udpv6_recvmsg(struct sock *sk, struct msghdr *msg,
+					    size_t len, int flags));
+
+struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
+				  netdev_features_t features, bool is_ipv6);
+
+static inline int udp_lib_init_sock(struct sock *sk)
+{
+	struct udp_sock *up = udp_sk(sk);
+
+	sk->sk_drop_counters = &up->drop_counters;
+	skb_queue_head_init(&up->reader_queue);
+	INIT_HLIST_NODE(&up->tunnel_list);
+	up->forward_threshold = sk->sk_rcvbuf >> 2;
+	set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
+
+	up->udp_prod_queue = kzalloc_objs(*up->udp_prod_queue, nr_node_ids);
+	if (!up->udp_prod_queue)
+		return -ENOMEM;
+	for (int i = 0; i < nr_node_ids; i++)
+		init_llist_head(&up->udp_prod_queue[i].ll_root);
+	return 0;
+}
+
+static inline void udp_drops_inc(struct sock *sk)
+{
+	numa_drop_add(&udp_sk(sk)->drop_counters, 1);
+}
+
+/* hash routines shared between UDPv4/6 */
+static inline int udp_lib_hash(struct sock *sk)
+{
+	BUG();
+	return 0;
+}
+
+void udp_lib_unhash(struct sock *sk);
+void udp_lib_rehash(struct sock *sk, u16 new_hash, u16 new_hash4);
+u32 udp_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport,
+		const __be32 faddr, const __be16 fport);
+
+static inline void udp_lib_close(struct sock *sk, long timeout)
+{
+	sk_common_release(sk);
+}
+
+/* hash4 routines shared between UDPv4/6 */
+#if IS_ENABLED(CONFIG_BASE_SMALL)
+static inline void udp_lib_hash4(struct sock *sk, u16 hash)
+{
+}
+
+static inline void udp4_hash4(struct sock *sk)
+{
+}
+#else /* !CONFIG_BASE_SMALL */
+void udp_lib_hash4(struct sock *sk, u16 hash);
+void udp4_hash4(struct sock *sk);
+#endif /* CONFIG_BASE_SMALL */
+
+int udp_lib_get_port(struct sock *sk, unsigned short snum,
+		     unsigned int hash2_nulladdr);
+
+u32 udp_flow_hashrnd(void);
+
+static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
+				       int min, int max, bool use_eth)
+{
+	u32 hash;
+
+	if (min >= max) {
+		/* Use default range */
+		inet_get_local_port_range(net, &min, &max);
+	}
+
+	hash = skb_get_hash(skb);
+	if (unlikely(!hash)) {
+		if (use_eth) {
+			/* Can't find a normal hash, caller has indicated an
+			 * Ethernet packet so use that to compute a hash.
+			 */
+			hash = jhash(skb->data, 2 * ETH_ALEN,
+				     (__force u32) skb->protocol);
+		} else {
+			/* Can't derive any sort of hash for the packet, set
+			 * to some consistent random value.
+			 */
+			hash = udp_flow_hashrnd();
+		}
+	}
+
+	/* Since this is being sent on the wire obfuscate hash a bit
+	 * to minimize possibility that any useful information to an
+	 * attacker is leaked. Only upper 16 bits are relevant in the
+	 * computation for 16 bit port value.
+	 */
+	hash ^= hash << 16;
+
+	return htons(reciprocal_scale(hash, max - min + 1) + min);
+}
+
+static inline int udp_rqueue_get(struct sock *sk)
+{
+	return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
+}
+
+static inline bool udp_sk_bound_dev_eq(const struct net *net, int bound_dev_if,
+				       int dif, int sdif)
+{
+#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
+	return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
+				 bound_dev_if, dif, sdif);
+#else
+	return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
+#endif
+}
+
+/* net/ipv4/udp.c */
+void udp_destruct_common(struct sock *sk);
+void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
+int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
+void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
+struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off,
+			       int *err);
+static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
+					   int *err)
+{
+	int off = 0;
+
+	return __skb_recv_udp(sk, flags, &off, err);
+}
+
+enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb);
+bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
+int udp_err(struct sk_buff *, u32);
+int udp_abort(struct sock *sk, int err);
+int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
+INDIRECT_CALLABLE_DECLARE(int udp_recvmsg(struct sock *sk, struct msghdr *msg,
+					  size_t len, int flags));
+void udp_splice_eof(struct socket *sock);
+int udp_push_pending_frames(struct sock *sk);
+void udp_flush_pending_frames(struct sock *sk);
+int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
+void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
+int udp_rcv(struct sk_buff *skb);
+int udp_ioctl(struct sock *sk, int cmd, int *karg);
+int udp_pre_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len);
+int __udp_disconnect(struct sock *sk, int flags);
+int udp_disconnect(struct sock *sk, int flags);
+__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
+struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
+				       netdev_features_t features,
+				       bool is_ipv6);
+int udp_lib_getsockopt(struct sock *sk, int level, int optname,
+		       sockopt_t *opt);
+int udp_lib_setsockopt(struct sock *sk, int level, int optname,
+		       sockptr_t optval, unsigned int optlen,
+		       int (*push_pending_frames)(struct sock *));
+struct sock *udp4_lib_lookup(const struct net *net, __be32 saddr, __be16 sport,
+			     __be32 daddr, __be16 dport, int dif);
+struct sock *__udp4_lib_lookup(const struct net *net, __be32 saddr,
+			       __be16 sport, __be32 daddr, __be16 dport,
+			       int dif, int sdif, struct sk_buff *skb);
+struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
+				 __be16 sport, __be16 dport);
+struct sock *udp6_lib_lookup(const struct net *net,
+			     const struct in6_addr *saddr, __be16 sport,
+			     const struct in6_addr *daddr, __be16 dport,
+			     int dif);
+struct sock *__udp6_lib_lookup(const struct net *net,
+			       const struct in6_addr *saddr, __be16 sport,
+			       const struct in6_addr *daddr, __be16 dport,
+			       int dif, int sdif, struct sk_buff *skb);
+struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
+				 __be16 sport, __be16 dport);
+int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
+
+/* UDP uses skb->dev_scratch to cache as much information as possible and avoid
+ * possibly multiple cache miss on dequeue()
+ */
+struct udp_dev_scratch {
+	/* skb->truesize and the stateless bit are embedded in a single field;
+	 * do not use a bitfield since the compiler emits better/smaller code
+	 * this way
+	 */
+	u32 _tsize_state;
+
+#if BITS_PER_LONG == 64
+	/* len and the bit needed to compute skb_csum_unnecessary
+	 * will be on cold cache lines at recvmsg time.
+	 * skb->len can be stored on 16 bits since the udp header has been
+	 * already validated and pulled.
+	 */
+	u16 len;
+	bool is_linear;
+	bool csum_unnecessary;
+#endif
+};
+
+static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
+{
+	return (struct udp_dev_scratch *)&skb->dev_scratch;
+}
+
+#if BITS_PER_LONG == 64
+static inline unsigned int udp_skb_len(struct sk_buff *skb)
+{
+	return udp_skb_scratch(skb)->len;
+}
+
+static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
+{
+	return udp_skb_scratch(skb)->csum_unnecessary;
+}
+
+static inline bool udp_skb_is_linear(struct sk_buff *skb)
+{
+	return udp_skb_scratch(skb)->is_linear;
+}
+
+#else
+static inline unsigned int udp_skb_len(struct sk_buff *skb)
+{
+	return skb->len;
+}
+
+static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
+{
+	return skb_csum_unnecessary(skb);
+}
+
+static inline bool udp_skb_is_linear(struct sk_buff *skb)
+{
+	return !skb_is_nonlinear(skb);
+}
+#endif
+
+static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
+				  struct iov_iter *to)
+{
+	return copy_to_iter_full(skb->data + off, len, to) ? 0 : -EFAULT;
+}
+
+/*
+ *	SNMP statistics for UDP
+ */
+#define __UDP_INC_STATS(net, field)				\
+	__SNMP_INC_STATS((net)->mib.udp_statistics, field)
+#define UDP_INC_STATS(net, field)				\
+	SNMP_INC_STATS((net)->mib.udp_statistics, field)
+#define __UDP6_INC_STATS(net, field)				\
+	__SNMP_INC_STATS((net)->mib.udp_stats_in6, field)
+#define UDP6_INC_STATS(net, field)				\
+	SNMP_INC_STATS((net)->mib.udp_stats_in6, field)
+
+#if IS_ENABLED(CONFIG_IPV6)
+#define __UDPX_MIB(sk, ipv4)					\
+	({							\
+		ipv4 ? sock_net(sk)->mib.udp_statistics :	\
+			sock_net(sk)->mib.udp_stats_in6;	\
+	})
+#else
+#define __UDPX_MIB(sk, ipv4)					\
+	({							\
+		sock_net(sk)->mib.udp_statistics;		\
+	})
+#endif
+
+#define __UDPX_INC_STATS(sk, field) \
+	__SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
+
+#ifdef CONFIG_PROC_FS
+struct udp_seq_afinfo {
+	sa_family_t			family;
+};
+
+struct udp_iter_state {
+	struct seq_net_private  p;
+	int			bucket;
+};
+
+void *udp_seq_start(struct seq_file *seq, loff_t *pos);
+void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
+void udp_seq_stop(struct seq_file *seq, void *v);
+
+int udp4_proc_init(void);
+void udp4_proc_exit(void);
+#endif /* CONFIG_PROC_FS */
+
+int udpv4_offload_init(void);
+
+void udp_init(void);
+
+DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
+void udp_encap_enable(void);
+void udp_encap_disable(void);
+#if IS_ENABLED(CONFIG_IPV6)
+DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
+void udpv6_encap_enable(void);
+#endif
+
+static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
+					      struct sk_buff *skb, bool ipv4)
+{
+	netdev_features_t features = NETIF_F_SG;
+	struct sk_buff *segs;
+	int drop_count;
+
+	/*
+	 * Segmentation in UDP receive path is only for UDP GRO, drop udp
+	 * fragmentation offload (UFO) packets.
+	 */
+	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) {
+		drop_count = 1;
+		goto drop;
+	}
+
+	/* Avoid csum recalculation by skb_segment unless userspace explicitly
+	 * asks for the final checksum values
+	 */
+	if (!inet_get_convert_csum(sk))
+		features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
+
+	/* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
+	 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
+	 * packets in udp_gro_complete_segment. As does UDP GSO, verified by
+	 * udp_send_skb. But when those packets are looped in dev_loopback_xmit
+	 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
+	 * Reset in this specific case, where PARTIAL is both correct and
+	 * required.
+	 */
+	if (skb->pkt_type == PACKET_LOOPBACK)
+		skb->ip_summed = CHECKSUM_PARTIAL;
+
+	/* the GSO CB lays after the UDP one, no need to save and restore any
+	 * CB fragment
+	 */
+	segs = __skb_gso_segment(skb, features, false);
+	if (IS_ERR_OR_NULL(segs)) {
+		drop_count = skb_shinfo(skb)->gso_segs;
+		goto drop;
+	}
+
+	consume_skb(skb);
+	return segs;
+
+drop:
+	sk_drops_add(sk, drop_count);
+	SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, drop_count);
+	kfree_skb(skb);
+	return NULL;
+}
+
+static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
+{
+	/* UDP packets generated with UDP_SEGMENT and traversing:
+	 *
+	 * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
+	 *
+	 * can reach an UDP socket with CHECKSUM_NONE, because
+	 * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
+	 * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
+	 * have a valid checksum, as the GRO engine validates the UDP csum
+	 * before the aggregation and nobody strips such info in between.
+	 * Instead of adding another check in the tunnel fastpath, we can force
+	 * a valid csum after the segmentation.
+	 * Additionally fixup the UDP CB.
+	 */
+	if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
+		skb->csum_valid = 1;
+}
+
+#ifdef CONFIG_BPF_SYSCALL
+struct sk_psock;
+int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
+#endif
+
+#endif	/* _UDP_H */