/*
   * 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 AF_INET socket handler.
   *
   * Version:	@(#)sock.h	1.0.4	05/13/93
   *

   * Authors:	Ross Biro

   *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
   *		Corey Minyard <wf-rch!minyard@relay.EU.net>
   *		Florian La Roche <flla@stud.uni-sb.de>
   *
   * Fixes:
   *		Alan Cox	:	Volatiles in skbuff pointers. See
   *					skbuff comments. May be overdone,
   *					better to prove they can be removed
   *					than the reverse.
   *		Alan Cox	:	Added a zapped field for tcp to note
   *					a socket is reset and must stay shut up
   *		Alan Cox	:	New fields for options
   *	Pauline Middelink	:	identd support
   *		Alan Cox	:	Eliminate low level recv/recvfrom
   *		David S. Miller	:	New socket lookup architecture.
   *              Steve Whitehouse:       Default routines for sock_ops
   *              Arnaldo C. Melo :	removed net_pinfo, tp_pinfo and made
   *              			protinfo be just a void pointer, as the
   *              			protocol specific parts were moved to
   *              			respective headers and ipv4/v6, etc now
   *              			use private slabcaches for its socks
   *              Pedro Hortas	:	New flags field for socket options
   *
   *
   *		This program is free software; you can redistribute it and/or
   *		modify it under the terms of the GNU General Public License
   *		as published by the Free Software Foundation; either version
   *		2 of the License, or (at your option) any later version.
   */
  #ifndef _SOCK_H
  #define _SOCK_H

  #include <linux/hardirq.h>

  #include <linux/kernel.h>

  #include <linux/list.h>

  #include <linux/list_nulls.h>

  #include <linux/timer.h>
  #include <linux/cache.h>

  #include <linux/bitops.h>

  #include <linux/lockdep.h>

  #include <linux/netdevice.h>
  #include <linux/skbuff.h>	/* struct sk_buff */

  #include <linux/mm.h>

  #include <linux/security.h>

  #include <linux/slab.h>

  #include <linux/uaccess.h>

  #include <linux/page_counter.h>

  #include <linux/memcontrol.h>

  #include <linux/static_key.h>

  #include <linux/sched.h>

  #include <linux/wait.h>

  #include <linux/cgroup-defs.h>

  
  #include <linux/filter.h>

  #include <linux/rculist_nulls.h>

  #include <linux/poll.h>

  #include <linux/atomic.h>

  #include <linux/refcount.h>

  #include <net/dst.h>
  #include <net/checksum.h>

  #include <net/tcp_states.h>

  #include <linux/net_tstamp.h>

  #include <net/smc.h>

  
  /*
   * This structure really needs to be cleaned up.
   * Most of it is for TCP, and not used by any of
   * the other protocols.
   */
  
  /* Define this to get the SOCK_DBG debugging facility. */
  #define SOCK_DEBUGGING
  #ifdef SOCK_DEBUGGING
  #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
  					printk(KERN_DEBUG msg); } while (0)
  #else

  /* Validate arguments and do nothing */

  static inline __printf(2, 3)

  void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)

  {
  }

  #endif
  
  /* This is the per-socket lock.  The spinlock provides a synchronization
   * between user contexts and software interrupt processing, whereas the
   * mini-semaphore synchronizes multiple users amongst themselves.
   */

  typedef struct {
  	spinlock_t		slock;

  	int			owned;

  	wait_queue_head_t	wq;

  	/*
  	 * We express the mutex-alike socket_lock semantics
  	 * to the lock validator by explicitly managing
  	 * the slock as a lock variant (in addition to
  	 * the slock itself):
  	 */
  #ifdef CONFIG_DEBUG_LOCK_ALLOC
  	struct lockdep_map dep_map;
  #endif

  } socket_lock_t;

  struct sock;

  struct proto;

  struct net;

  typedef __u32 __bitwise __portpair;
  typedef __u64 __bitwise __addrpair;

  /**

   *	struct sock_common - minimal network layer representation of sockets

   *	@skc_daddr: Foreign IPv4 addr
   *	@skc_rcv_saddr: Bound local IPv4 addr

   *	@skc_hash: hash value used with various protocol lookup tables

   *	@skc_u16hashes: two u16 hash values used by UDP lookup tables

   *	@skc_dport: placeholder for inet_dport/tw_dport
   *	@skc_num: placeholder for inet_num/tw_num

   *	@skc_family: network address family
   *	@skc_state: Connection state
   *	@skc_reuse: %SO_REUSEADDR setting

   *	@skc_reuseport: %SO_REUSEPORT setting

   *	@skc_bound_dev_if: bound device index if != 0

   *	@skc_bind_node: bind hash linkage for various protocol lookup tables

   *	@skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol

   *	@skc_prot: protocol handlers inside a network family

   *	@skc_net: reference to the network namespace of this socket

   *	@skc_node: main hash linkage for various protocol lookup tables
   *	@skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
   *	@skc_tx_queue_mapping: tx queue number for this connection

   *	@skc_flags: place holder for sk_flags
   *		%SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
   *		%SO_OOBINLINE settings, %SO_TIMESTAMPING settings

   *	@skc_incoming_cpu: record/match cpu processing incoming packets

   *	@skc_refcnt: reference count

   *
   *	This is the minimal network layer representation of sockets, the header

   *	for struct sock and struct inet_timewait_sock.
   */

  struct sock_common {

  	/* skc_daddr and skc_rcv_saddr must be grouped on a 8 bytes aligned

  	 * address on 64bit arches : cf INET_MATCH()

  	 */

  	union {

  		__addrpair	skc_addrpair;

  		struct {
  			__be32	skc_daddr;
  			__be32	skc_rcv_saddr;
  		};
  	};

  	union  {
  		unsigned int	skc_hash;
  		__u16		skc_u16hashes[2];
  	};

  	/* skc_dport && skc_num must be grouped as well */
  	union {

  		__portpair	skc_portpair;

  		struct {
  			__be16	skc_dport;
  			__u16	skc_num;
  		};
  	};

  	unsigned short		skc_family;
  	volatile unsigned char	skc_state;

  	unsigned char		skc_reuse:4;

  	unsigned char		skc_reuseport:1;
  	unsigned char		skc_ipv6only:1;

  	unsigned char		skc_net_refcnt:1;

  	int			skc_bound_dev_if;

  	union {
  		struct hlist_node	skc_bind_node;

  		struct hlist_node	skc_portaddr_node;

  	};

  	struct proto		*skc_prot;

  	possible_net_t		skc_net;

  
  #if IS_ENABLED(CONFIG_IPV6)
  	struct in6_addr		skc_v6_daddr;
  	struct in6_addr		skc_v6_rcv_saddr;
  #endif

  	atomic64_t		skc_cookie;

  	/* following fields are padding to force
  	 * offset(struct sock, sk_refcnt) == 128 on 64bit arches
  	 * assuming IPV6 is enabled. We use this padding differently
  	 * for different kind of 'sockets'
  	 */
  	union {
  		unsigned long	skc_flags;
  		struct sock	*skc_listener; /* request_sock */
  		struct inet_timewait_death_row *skc_tw_dr; /* inet_timewait_sock */
  	};

  	/*
  	 * fields between dontcopy_begin/dontcopy_end
  	 * are not copied in sock_copy()
  	 */

  	/* private: */

  	int			skc_dontcopy_begin[0];

  	/* public: */

  	union {
  		struct hlist_node	skc_node;
  		struct hlist_nulls_node skc_nulls_node;
  	};
  	int			skc_tx_queue_mapping;

  	union {
  		int		skc_incoming_cpu;
  		u32		skc_rcv_wnd;

  		u32		skc_tw_rcv_nxt; /* struct tcp_timewait_sock  */

  	};

  	refcount_t		skc_refcnt;

  	/* private: */

  	int                     skc_dontcopy_end[0];

  	union {
  		u32		skc_rxhash;
  		u32		skc_window_clamp;

  		u32		skc_tw_snd_nxt; /* struct tcp_timewait_sock */

  	};

  	/* public: */

  };
  
  /**
    *	struct sock - network layer representation of sockets

    *	@__sk_common: shared layout with inet_timewait_sock

    *	@sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
    *	@sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
    *	@sk_lock:	synchronizer

    *	@sk_kern_sock: True if sock is using kernel lock classes

    *	@sk_rcvbuf: size of receive buffer in bytes

    *	@sk_wq: sock wait queue and async head

    *	@sk_rx_dst: receive input route used by early demux

    *	@sk_dst_cache: destination cache

    *	@sk_dst_pending_confirm: need to confirm neighbour

    *	@sk_policy: flow policy

    *	@sk_receive_queue: incoming packets
    *	@sk_wmem_alloc: transmit queue bytes committed

    *	@sk_tsq_flags: TCP Small Queues flags

    *	@sk_write_queue: Packet sending queue
    *	@sk_omem_alloc: "o" is "option" or "other"
    *	@sk_wmem_queued: persistent queue size
    *	@sk_forward_alloc: space allocated forward

    *	@sk_napi_id: id of the last napi context to receive data for sk

    *	@sk_ll_usec: usecs to busypoll when there is no data

    *	@sk_allocation: allocation mode

    *	@sk_pacing_rate: Pacing rate (if supported by transport/packet scheduler)

    *	@sk_pacing_status: Pacing status (requested, handled by sch_fq)

    *	@sk_max_pacing_rate: Maximum pacing rate (%SO_MAX_PACING_RATE)

    *	@sk_sndbuf: size of send buffer in bytes

    *	@__sk_flags_offset: empty field used to determine location of bitfield

    *	@sk_padding: unused element for alignment

    *	@sk_no_check_tx: %SO_NO_CHECK setting, set checksum in TX packets
    *	@sk_no_check_rx: allow zero checksum in RX packets

    *	@sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)

    *	@sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)

    *	@sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)

    *	@sk_gso_max_size: Maximum GSO segment size to build

    *	@sk_gso_max_segs: Maximum number of GSO segments

    *	@sk_lingertime: %SO_LINGER l_linger setting

    *	@sk_backlog: always used with the per-socket spinlock held
    *	@sk_callback_lock: used with the callbacks in the end of this struct
    *	@sk_error_queue: rarely used

    *	@sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
    *			  IPV6_ADDRFORM for instance)

    *	@sk_err: last error

    *	@sk_err_soft: errors that don't cause failure but are the cause of a
    *		      persistent failure not just 'timed out'

    *	@sk_drops: raw/udp drops counter

    *	@sk_ack_backlog: current listen backlog
    *	@sk_max_ack_backlog: listen backlog set in listen()

    *	@sk_uid: user id of owner

    *	@sk_priority: %SO_PRIORITY setting
    *	@sk_type: socket type (%SOCK_STREAM, etc)
    *	@sk_protocol: which protocol this socket belongs in this network family

    *	@sk_peer_pid: &struct pid for this socket's peer
    *	@sk_peer_cred: %SO_PEERCRED setting

    *	@sk_rcvlowat: %SO_RCVLOWAT setting
    *	@sk_rcvtimeo: %SO_RCVTIMEO setting
    *	@sk_sndtimeo: %SO_SNDTIMEO setting

    *	@sk_txhash: computed flow hash for use on transmit

    *	@sk_filter: socket filtering instructions

    *	@sk_timer: sock cleanup timer
    *	@sk_stamp: time stamp of last packet received

    *	@sk_stamp_seq: lock for accessing sk_stamp on 32 bit architectures only

    *	@sk_tsflags: SO_TIMESTAMPING socket options

    *	@sk_tskey: counter to disambiguate concurrent tstamp requests

    *	@sk_zckey: counter to order MSG_ZEROCOPY notifications

    *	@sk_socket: Identd and reporting IO signals
    *	@sk_user_data: RPC layer private data

    *	@sk_frag: cached page frag

    *	@sk_peek_off: current peek_offset value

    *	@sk_send_head: front of stuff to transmit

    *	@sk_security: used by security modules

    *	@sk_mark: generic packet mark

    *	@sk_cgrp_data: cgroup data for this cgroup

    *	@sk_memcg: this socket's memory cgroup association

    *	@sk_write_pending: a write to stream socket waits to start
    *	@sk_state_change: callback to indicate change in the state of the sock
    *	@sk_data_ready: callback to indicate there is data to be processed
    *	@sk_write_space: callback to indicate there is bf sending space available
    *	@sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
    *	@sk_backlog_rcv: callback to process the backlog
    *	@sk_destruct: called at sock freeing time, i.e. when all refcnt == 0

    *	@sk_reuseport_cb: reuseport group container

    *	@sk_rcu: used during RCU grace period
    */

  struct sock {
  	/*

  	 * Now struct inet_timewait_sock also uses sock_common, so please just

  	 * don't add nothing before this first member (__sk_common) --acme
  	 */
  	struct sock_common	__sk_common;

  #define sk_node			__sk_common.skc_node
  #define sk_nulls_node		__sk_common.skc_nulls_node
  #define sk_refcnt		__sk_common.skc_refcnt

  #define sk_tx_queue_mapping	__sk_common.skc_tx_queue_mapping

  #define sk_dontcopy_begin	__sk_common.skc_dontcopy_begin
  #define sk_dontcopy_end		__sk_common.skc_dontcopy_end

  #define sk_hash			__sk_common.skc_hash

  #define sk_portpair		__sk_common.skc_portpair

  #define sk_num			__sk_common.skc_num
  #define sk_dport		__sk_common.skc_dport

  #define sk_addrpair		__sk_common.skc_addrpair
  #define sk_daddr		__sk_common.skc_daddr
  #define sk_rcv_saddr		__sk_common.skc_rcv_saddr

  #define sk_family		__sk_common.skc_family
  #define sk_state		__sk_common.skc_state
  #define sk_reuse		__sk_common.skc_reuse

  #define sk_reuseport		__sk_common.skc_reuseport

  #define sk_ipv6only		__sk_common.skc_ipv6only

  #define sk_net_refcnt		__sk_common.skc_net_refcnt

  #define sk_bound_dev_if		__sk_common.skc_bound_dev_if

  #define sk_bind_node		__sk_common.skc_bind_node

  #define sk_prot			__sk_common.skc_prot

  #define sk_net			__sk_common.skc_net

  #define sk_v6_daddr		__sk_common.skc_v6_daddr
  #define sk_v6_rcv_saddr	__sk_common.skc_v6_rcv_saddr

  #define sk_cookie		__sk_common.skc_cookie

  #define sk_incoming_cpu		__sk_common.skc_incoming_cpu

  #define sk_flags		__sk_common.skc_flags

  #define sk_rxhash		__sk_common.skc_rxhash

  	socket_lock_t		sk_lock;

  	atomic_t		sk_drops;
  	int			sk_rcvlowat;
  	struct sk_buff_head	sk_error_queue;

  	struct sk_buff_head	sk_receive_queue;

  	/*
  	 * The backlog queue is special, it is always used with
  	 * the per-socket spinlock held and requires low latency
  	 * access. Therefore we special case it's implementation.

  	 * Note : rmem_alloc is in this structure to fill a hole
  	 * on 64bit arches, not because its logically part of
  	 * backlog.

  	 */
  	struct {

  		atomic_t	rmem_alloc;
  		int		len;
  		struct sk_buff	*head;
  		struct sk_buff	*tail;

  	} sk_backlog;

  #define sk_rmem_alloc sk_backlog.rmem_alloc

  	int			sk_forward_alloc;

  #ifdef CONFIG_NET_RX_BUSY_POLL

  	unsigned int		sk_ll_usec;

  	/* ===== mostly read cache line ===== */
  	unsigned int		sk_napi_id;

  #endif

  	int			sk_rcvbuf;
  
  	struct sk_filter __rcu	*sk_filter;

  	union {
  		struct socket_wq __rcu	*sk_wq;
  		struct socket_wq	*sk_wq_raw;
  	};

  #ifdef CONFIG_XFRM

  	struct xfrm_policy __rcu *sk_policy[2];

  #endif

  	struct dst_entry	*sk_rx_dst;

  	struct dst_entry __rcu	*sk_dst_cache;

  	atomic_t		sk_omem_alloc;

  	int			sk_sndbuf;

  
  	/* ===== cache line for TX ===== */
  	int			sk_wmem_queued;

  	refcount_t		sk_wmem_alloc;

  	unsigned long		sk_tsq_flags;
  	struct sk_buff		*sk_send_head;

  	struct sk_buff_head	sk_write_queue;

  	__s32			sk_peek_off;
  	int			sk_write_pending;

  	__u32			sk_dst_pending_confirm;

  	u32			sk_pacing_status; /* see enum sk_pacing */

  	long			sk_sndtimeo;
  	struct timer_list	sk_timer;
  	__u32			sk_priority;
  	__u32			sk_mark;
  	u32			sk_pacing_rate; /* bytes per second */
  	u32			sk_max_pacing_rate;
  	struct page_frag	sk_frag;
  	netdev_features_t	sk_route_caps;
  	netdev_features_t	sk_route_nocaps;
  	int			sk_gso_type;
  	unsigned int		sk_gso_max_size;
  	gfp_t			sk_allocation;
  	__u32			sk_txhash;

  
  	/*
  	 * Because of non atomicity rules, all
  	 * changes are protected by socket lock.
  	 */

  	unsigned int		__sk_flags_offset[0];
  #ifdef __BIG_ENDIAN_BITFIELD
  #define SK_FL_PROTO_SHIFT  16
  #define SK_FL_PROTO_MASK   0x00ff0000
  
  #define SK_FL_TYPE_SHIFT   0
  #define SK_FL_TYPE_MASK    0x0000ffff
  #else
  #define SK_FL_PROTO_SHIFT  8
  #define SK_FL_PROTO_MASK   0x0000ff00
  
  #define SK_FL_TYPE_SHIFT   16
  #define SK_FL_TYPE_MASK    0xffff0000
  #endif

  	unsigned int		sk_padding : 1,
  				sk_kern_sock : 1,

  				sk_no_check_tx : 1,
  				sk_no_check_rx : 1,

  				sk_userlocks : 4,
  				sk_protocol  : 8,
  				sk_type      : 16;

  #define SK_PROTOCOL_MAX U8_MAX

  	u16			sk_gso_max_segs;

  	unsigned long	        sk_lingertime;

  	struct proto		*sk_prot_creator;

  	rwlock_t		sk_callback_lock;
  	int			sk_err,
  				sk_err_soft;

  	u32			sk_ack_backlog;
  	u32			sk_max_ack_backlog;

  	kuid_t			sk_uid;

  	struct pid		*sk_peer_pid;
  	const struct cred	*sk_peer_cred;

  	long			sk_rcvtimeo;

  	ktime_t			sk_stamp;

  #if BITS_PER_LONG==32
  	seqlock_t		sk_stamp_seq;
  #endif

  	u16			sk_tsflags;

  	u8			sk_shutdown;

  	u32			sk_tskey;

  	atomic_t		sk_zckey;

  	struct socket		*sk_socket;
  	void			*sk_user_data;

  #ifdef CONFIG_SECURITY

  	void			*sk_security;

  #endif

  	struct sock_cgroup_data	sk_cgrp_data;

  	struct mem_cgroup	*sk_memcg;

  	void			(*sk_state_change)(struct sock *sk);

  	void			(*sk_data_ready)(struct sock *sk);

  	void			(*sk_write_space)(struct sock *sk);
  	void			(*sk_error_report)(struct sock *sk);

  	int			(*sk_backlog_rcv)(struct sock *sk,
  						  struct sk_buff *skb);

  	void                    (*sk_destruct)(struct sock *sk);

  	struct sock_reuseport __rcu	*sk_reuseport_cb;

  	struct rcu_head		sk_rcu;

  };

  enum sk_pacing {
  	SK_PACING_NONE		= 0,
  	SK_PACING_NEEDED	= 1,
  	SK_PACING_FQ		= 2,
  };

  #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data)))
  
  #define rcu_dereference_sk_user_data(sk)	rcu_dereference(__sk_user_data((sk)))
  #define rcu_assign_sk_user_data(sk, ptr)	rcu_assign_pointer(__sk_user_data((sk)), ptr)

  /*
   * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
   * or not whether his port will be reused by someone else. SK_FORCE_REUSE
   * on a socket means that the socket will reuse everybody else's port
   * without looking at the other's sk_reuse value.
   */
  
  #define SK_NO_REUSE	0
  #define SK_CAN_REUSE	1
  #define SK_FORCE_REUSE	2

  int sk_set_peek_off(struct sock *sk, int val);

  static inline int sk_peek_offset(struct sock *sk, int flags)
  {

  	if (unlikely(flags & MSG_PEEK)) {

  		return READ_ONCE(sk->sk_peek_off);

  	}
  
  	return 0;

  }
  
  static inline void sk_peek_offset_bwd(struct sock *sk, int val)
  {

  	s32 off = READ_ONCE(sk->sk_peek_off);
  
  	if (unlikely(off >= 0)) {
  		off = max_t(s32, off - val, 0);
  		WRITE_ONCE(sk->sk_peek_off, off);

  	}
  }
  
  static inline void sk_peek_offset_fwd(struct sock *sk, int val)
  {

  	sk_peek_offset_bwd(sk, -val);

  }

  /*
   * Hashed lists helper routines
   */

  static inline struct sock *sk_entry(const struct hlist_node *node)
  {
  	return hlist_entry(node, struct sock, sk_node);
  }

  static inline struct sock *__sk_head(const struct hlist_head *head)

  {
  	return hlist_entry(head->first, struct sock, sk_node);
  }

  static inline struct sock *sk_head(const struct hlist_head *head)

  {
  	return hlist_empty(head) ? NULL : __sk_head(head);
  }

  static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
  {
  	return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
  }
  
  static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
  {
  	return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
  }

  static inline struct sock *sk_next(const struct sock *sk)

  {

  	return hlist_entry_safe(sk->sk_node.next, struct sock, sk_node);

  }

  static inline struct sock *sk_nulls_next(const struct sock *sk)
  {
  	return (!is_a_nulls(sk->sk_nulls_node.next)) ?
  		hlist_nulls_entry(sk->sk_nulls_node.next,
  				  struct sock, sk_nulls_node) :
  		NULL;
  }

  static inline bool sk_unhashed(const struct sock *sk)

  {
  	return hlist_unhashed(&sk->sk_node);
  }

  static inline bool sk_hashed(const struct sock *sk)

  {

  	return !sk_unhashed(sk);

  }

  static inline void sk_node_init(struct hlist_node *node)

  {
  	node->pprev = NULL;
  }

  static inline void sk_nulls_node_init(struct hlist_nulls_node *node)

  {
  	node->pprev = NULL;
  }

  static inline void __sk_del_node(struct sock *sk)

  {
  	__hlist_del(&sk->sk_node);
  }

  /* NB: equivalent to hlist_del_init_rcu */

  static inline bool __sk_del_node_init(struct sock *sk)

  {
  	if (sk_hashed(sk)) {
  		__sk_del_node(sk);
  		sk_node_init(&sk->sk_node);

  		return true;

  	}

  	return false;

  }
  
  /* Grab socket reference count. This operation is valid only
     when sk is ALREADY grabbed f.e. it is found in hash table
     or a list and the lookup is made under lock preventing hash table
     modifications.
   */

  static __always_inline void sock_hold(struct sock *sk)

  {

  	refcount_inc(&sk->sk_refcnt);

  }
  
  /* Ungrab socket in the context, which assumes that socket refcnt
     cannot hit zero, f.e. it is true in context of any socketcall.
   */

  static __always_inline void __sock_put(struct sock *sk)

  {

  	refcount_dec(&sk->sk_refcnt);

  }

  static inline bool sk_del_node_init(struct sock *sk)

  {

  	bool rc = __sk_del_node_init(sk);

  
  	if (rc) {
  		/* paranoid for a while -acme */

  		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);

  		__sock_put(sk);
  	}
  	return rc;
  }

  #define sk_del_node_init_rcu(sk)	sk_del_node_init(sk)

  static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)

  {
  	if (sk_hashed(sk)) {

  		hlist_nulls_del_init_rcu(&sk->sk_nulls_node);

  		return true;

  	}

  	return false;

  }

  static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)

  {

  	bool rc = __sk_nulls_del_node_init_rcu(sk);

  
  	if (rc) {
  		/* paranoid for a while -acme */

  		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);

  		__sock_put(sk);
  	}
  	return rc;
  }

  static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)

  {
  	hlist_add_head(&sk->sk_node, list);
  }

  static inline void sk_add_node(struct sock *sk, struct hlist_head *list)

  {
  	sock_hold(sk);
  	__sk_add_node(sk, list);
  }

  static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)

  {
  	sock_hold(sk);

  	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
  	    sk->sk_family == AF_INET6)
  		hlist_add_tail_rcu(&sk->sk_node, list);
  	else
  		hlist_add_head_rcu(&sk->sk_node, list);

  }

  static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)

  {

  	hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);

  }

  static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)

  {
  	sock_hold(sk);

  	__sk_nulls_add_node_rcu(sk, list);

  }

  static inline void __sk_del_bind_node(struct sock *sk)

  {
  	__hlist_del(&sk->sk_bind_node);
  }

  static inline void sk_add_bind_node(struct sock *sk,

  					struct hlist_head *list)
  {
  	hlist_add_head(&sk->sk_bind_node, list);
  }

  #define sk_for_each(__sk, list) \
  	hlist_for_each_entry(__sk, list, sk_node)
  #define sk_for_each_rcu(__sk, list) \
  	hlist_for_each_entry_rcu(__sk, list, sk_node)

  #define sk_nulls_for_each(__sk, node, list) \
  	hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
  #define sk_nulls_for_each_rcu(__sk, node, list) \
  	hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)

  #define sk_for_each_from(__sk) \
  	hlist_for_each_entry_from(__sk, sk_node)

  #define sk_nulls_for_each_from(__sk, node) \
  	if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
  		hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)

  #define sk_for_each_safe(__sk, tmp, list) \
  	hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
  #define sk_for_each_bound(__sk, list) \
  	hlist_for_each_entry(__sk, list, sk_bind_node)

  /**

   * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset

   * @tpos:	the type * to use as a loop cursor.
   * @pos:	the &struct hlist_node to use as a loop cursor.
   * @head:	the head for your list.
   * @offset:	offset of hlist_node within the struct.
   *
   */

  #define sk_for_each_entry_offset_rcu(tpos, pos, head, offset)		       \
  	for (pos = rcu_dereference((head)->first);			       \
  	     pos != NULL &&						       \

  		({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;});       \

  	     pos = rcu_dereference(pos->next))

  static inline struct user_namespace *sk_user_ns(struct sock *sk)
  {
  	/* Careful only use this in a context where these parameters
  	 * can not change and must all be valid, such as recvmsg from
  	 * userspace.
  	 */
  	return sk->sk_socket->file->f_cred->user_ns;
  }

  /* Sock flags */
  enum sock_flags {
  	SOCK_DEAD,
  	SOCK_DONE,
  	SOCK_URGINLINE,
  	SOCK_KEEPOPEN,
  	SOCK_LINGER,
  	SOCK_DESTROY,
  	SOCK_BROADCAST,
  	SOCK_TIMESTAMP,
  	SOCK_ZAPPED,
  	SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
  	SOCK_DBG, /* %SO_DEBUG setting */
  	SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */

  	SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */

  	SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
  	SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */

  	SOCK_MEMALLOC, /* VM depends on this socket for swapping */

  	SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */

  	SOCK_FASYNC, /* fasync() active */

  	SOCK_RXQ_OVFL,

  	SOCK_ZEROCOPY, /* buffers from userspace */

  	SOCK_WIFI_STATUS, /* push wifi status to userspace */

  	SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
  		     * Will use last 4 bytes of packet sent from
  		     * user-space instead.
  		     */

  	SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */

  	SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */

  	SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */

  };

  #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))

  static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
  {
  	nsk->sk_flags = osk->sk_flags;
  }

  static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
  {
  	__set_bit(flag, &sk->sk_flags);
  }
  
  static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
  {
  	__clear_bit(flag, &sk->sk_flags);
  }

  static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)

  {
  	return test_bit(flag, &sk->sk_flags);
  }

  #ifdef CONFIG_NET
  extern struct static_key memalloc_socks;
  static inline int sk_memalloc_socks(void)
  {
  	return static_key_false(&memalloc_socks);
  }
  #else
  
  static inline int sk_memalloc_socks(void)
  {
  	return 0;
  }
  
  #endif

  static inline gfp_t sk_gfp_mask(const struct sock *sk, gfp_t gfp_mask)

  {

  	return gfp_mask | (sk->sk_allocation & __GFP_MEMALLOC);

  }

  static inline void sk_acceptq_removed(struct sock *sk)
  {
  	sk->sk_ack_backlog--;
  }
  
  static inline void sk_acceptq_added(struct sock *sk)
  {
  	sk->sk_ack_backlog++;
  }

  static inline bool sk_acceptq_is_full(const struct sock *sk)

  {

  	return sk->sk_ack_backlog > sk->sk_max_ack_backlog;

  }
  
  /*
   * Compute minimal free write space needed to queue new packets.
   */

  static inline int sk_stream_min_wspace(const struct sock *sk)

  {

  	return sk->sk_wmem_queued >> 1;

  }

  static inline int sk_stream_wspace(const struct sock *sk)

  {
  	return sk->sk_sndbuf - sk->sk_wmem_queued;
  }

  void sk_stream_write_space(struct sock *sk);

  /* OOB backlog add */

  static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)

  {

  	/* dont let skb dst not refcounted, we are going to leave rcu lock */

  	skb_dst_force(skb);

  
  	if (!sk->sk_backlog.tail)
  		sk->sk_backlog.head = skb;
  	else

  		sk->sk_backlog.tail->next = skb;

  
  	sk->sk_backlog.tail = skb;

  	skb->next = NULL;
  }

  /*
   * Take into account size of receive queue and backlog queue

   * Do not take into account this skb truesize,
   * to allow even a single big packet to come.

   */

  static inline bool sk_rcvqueues_full(const struct sock *sk, unsigned int limit)

  {
  	unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);

  	return qsize > limit;

  }

  /* The per-socket spinlock must be held here. */

  static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
  					      unsigned int limit)

  {

  	if (sk_rcvqueues_full(sk, limit))

  		return -ENOBUFS;

  	/*
  	 * If the skb was allocated from pfmemalloc reserves, only
  	 * allow SOCK_MEMALLOC sockets to use it as this socket is
  	 * helping free memory
  	 */
  	if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
  		return -ENOMEM;

  	__sk_add_backlog(sk, skb);

  	sk->sk_backlog.len += skb->truesize;
  	return 0;
  }

  int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);

  static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
  {

  	if (sk_memalloc_socks() && skb_pfmemalloc(skb))
  		return __sk_backlog_rcv(sk, skb);

  	return sk->sk_backlog_rcv(sk, skb);
  }

  static inline void sk_incoming_cpu_update(struct sock *sk)
  {

  	int cpu = raw_smp_processor_id();
  
  	if (unlikely(sk->sk_incoming_cpu != cpu))
  		sk->sk_incoming_cpu = cpu;

  }

  static inline void sock_rps_record_flow_hash(__u32 hash)

  {
  #ifdef CONFIG_RPS
  	struct rps_sock_flow_table *sock_flow_table;
  
  	rcu_read_lock();
  	sock_flow_table = rcu_dereference(rps_sock_flow_table);

  	rps_record_sock_flow(sock_flow_table, hash);

  	rcu_read_unlock();
  #endif
  }

  static inline void sock_rps_record_flow(const struct sock *sk)
  {

  #ifdef CONFIG_RPS

  	if (static_key_false(&rfs_needed)) {
  		/* Reading sk->sk_rxhash might incur an expensive cache line
  		 * miss.
  		 *
  		 * TCP_ESTABLISHED does cover almost all states where RFS
  		 * might be useful, and is cheaper [1] than testing :
  		 *	IPv4: inet_sk(sk)->inet_daddr
  		 * 	IPv6: ipv6_addr_any(&sk->sk_v6_daddr)
  		 * OR	an additional socket flag
  		 * [1] : sk_state and sk_prot are in the same cache line.
  		 */
  		if (sk->sk_state == TCP_ESTABLISHED)
  			sock_rps_record_flow_hash(sk->sk_rxhash);
  	}

  #endif

  }

  static inline void sock_rps_save_rxhash(struct sock *sk,
  					const struct sk_buff *skb)

  {
  #ifdef CONFIG_RPS

  	if (unlikely(sk->sk_rxhash != skb->hash))

  		sk->sk_rxhash = skb->hash;

  #endif
  }

  static inline void sock_rps_reset_rxhash(struct sock *sk)
  {
  #ifdef CONFIG_RPS

  	sk->sk_rxhash = 0;
  #endif
  }

  #define sk_wait_event(__sk, __timeo, __condition, __wait)		\

  	({	int __rc;						\
  		release_sock(__sk);					\
  		__rc = __condition;					\
  		if (!__rc) {						\

  			*(__timeo) = wait_woken(__wait,			\
  						TASK_INTERRUPTIBLE,	\
  						*(__timeo));		\

  		}							\

  		sched_annotate_sleep();					\

  		lock_sock(__sk);					\
  		__rc = __condition;					\
  		__rc;							\
  	})

  int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
  int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
  void sk_stream_wait_close(struct sock *sk, long timeo_p);
  int sk_stream_error(struct sock *sk, int flags, int err);
  void sk_stream_kill_queues(struct sock *sk);
  void sk_set_memalloc(struct sock *sk);
  void sk_clear_memalloc(struct sock *sk);

  void __sk_flush_backlog(struct sock *sk);
  
  static inline bool sk_flush_backlog(struct sock *sk)
  {
  	if (unlikely(READ_ONCE(sk->sk_backlog.tail))) {
  		__sk_flush_backlog(sk);
  		return true;
  	}
  	return false;
  }

  int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb);

  struct request_sock_ops;

  struct timewait_sock_ops;

  struct inet_hashinfo;

  struct raw_hashinfo;

  struct smc_hashinfo;

  struct module;

  /*

   * caches using SLAB_TYPESAFE_BY_RCU should let .next pointer from nulls nodes

   * un-modified. Special care is taken when initializing object to zero.
   */
  static inline void sk_prot_clear_nulls(struct sock *sk, int size)
  {
  	if (offsetof(struct sock, sk_node.next) != 0)
  		memset(sk, 0, offsetof(struct sock, sk_node.next));
  	memset(&sk->sk_node.pprev, 0,
  	       size - offsetof(struct sock, sk_node.pprev));
  }

  /* Networking protocol blocks we attach to sockets.
   * socket layer -> transport layer interface

   */
  struct proto {

  	void			(*close)(struct sock *sk,

  					long timeout);
  	int			(*connect)(struct sock *sk,

  					struct sockaddr *uaddr,

  					int addr_len);
  	int			(*disconnect)(struct sock *sk, int flags);

  	struct sock *		(*accept)(struct sock *sk, int flags, int *err,
  					  bool kern);

  
  	int			(*ioctl)(struct sock *sk, int cmd,
  					 unsigned long arg);
  	int			(*init)(struct sock *sk);

  	void			(*destroy)(struct sock *sk);

  	void			(*shutdown)(struct sock *sk, int how);

  	int			(*setsockopt)(struct sock *sk, int level,

  					int optname, char __user *optval,

  					unsigned int optlen);

  	int			(*getsockopt)(struct sock *sk, int level,
  					int optname, char __user *optval,
  					int __user *option);

  	void			(*keepalive)(struct sock *sk, int valbool);

  #ifdef CONFIG_COMPAT

  	int			(*compat_setsockopt)(struct sock *sk,
  					int level,
  					int optname, char __user *optval,

  					unsigned int optlen);

  	int			(*compat_getsockopt)(struct sock *sk,
  					int level,
  					int optname, char __user *optval,
  					int __user *option);

  	int			(*compat_ioctl)(struct sock *sk,
  					unsigned int cmd, unsigned long arg);

  #endif

  	int			(*sendmsg)(struct sock *sk, struct msghdr *msg,
  					   size_t len);
  	int			(*recvmsg)(struct sock *sk, struct msghdr *msg,

  					   size_t len, int noblock, int flags,
  					   int *addr_len);

  	int			(*sendpage)(struct sock *sk, struct page *page,
  					int offset, size_t size, int flags);

  	int			(*bind)(struct sock *sk,

  					struct sockaddr *uaddr, int addr_len);

  	int			(*backlog_rcv) (struct sock *sk,

  						struct sk_buff *skb);

  	void		(*release_cb)(struct sock *sk);

  	/* Keeping track of sk's, looking them up, and port selection methods. */

  	int			(*hash)(struct sock *sk);

  	void			(*unhash)(struct sock *sk);

  	void			(*rehash)(struct sock *sk);

  	int			(*get_port)(struct sock *sk, unsigned short snum);

  	/* Keeping track of sockets in use */

  #ifdef CONFIG_PROC_FS

  	unsigned int		inuse_idx;

  #endif

  	bool			(*stream_memory_free)(const struct sock *sk);

  	/* Memory pressure */

  	void			(*enter_memory_pressure)(struct sock *sk);

  	void			(*leave_memory_pressure)(struct sock *sk);

  	atomic_long_t		*memory_allocated;	/* Current allocated memory. */

  	struct percpu_counter	*sockets_allocated;	/* Current number of sockets. */

  	/*
  	 * Pressure flag: try to collapse.
  	 * Technical note: it is used by multiple contexts non atomically.

  	 * All the __sk_mem_schedule() is of this nature: accounting

  	 * is strict, actions are advisory and have some latency.
  	 */

  	unsigned long		*memory_pressure;

  	long			*sysctl_mem;

  	int			*sysctl_wmem;
  	int			*sysctl_rmem;
  	int			max_header;

  	bool			no_autobind;

  	struct kmem_cache	*slab;

  	unsigned int		obj_size;

  	int			slab_flags;

  	struct percpu_counter	*orphan_count;

  	struct request_sock_ops	*rsk_prot;

  	struct timewait_sock_ops *twsk_prot;

  	union {
  		struct inet_hashinfo	*hashinfo;

  		struct udp_table	*udp_table;

  		struct raw_hashinfo	*raw_hash;

  		struct smc_hashinfo	*smc_hash;

  	} h;

  	struct module		*owner;
  
  	char			name[32];
  
  	struct list_head	node;

  #ifdef SOCK_REFCNT_DEBUG
  	atomic_t		socks;
  #endif

  	int			(*diag_destroy)(struct sock *sk, int err);

  } __randomize_layout;

  int proto_register(struct proto *prot, int alloc_slab);
  void proto_unregister(struct proto *prot);

  #ifdef SOCK_REFCNT_DEBUG
  static inline void sk_refcnt_debug_inc(struct sock *sk)
  {
  	atomic_inc(&sk->sk_prot->socks);
  }
  
  static inline void sk_refcnt_debug_dec(struct sock *sk)
  {
  	atomic_dec(&sk->sk_prot->socks);
  	printk(KERN_DEBUG "%s socket %p released, %d are still alive
  ",
  	       sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
  }

  static inline void sk_refcnt_debug_release(const struct sock *sk)

  {

  	if (refcount_read(&sk->sk_refcnt) != 1)

  		printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d
  ",

  		       sk->sk_prot->name, sk, refcount_read(&sk->sk_refcnt));

  }
  #else /* SOCK_REFCNT_DEBUG */
  #define sk_refcnt_debug_inc(sk) do { } while (0)
  #define sk_refcnt_debug_dec(sk) do { } while (0)
  #define sk_refcnt_debug_release(sk) do { } while (0)
  #endif /* SOCK_REFCNT_DEBUG */

  static inline bool sk_stream_memory_free(const struct sock *sk)
  {
  	if (sk->sk_wmem_queued >= sk->sk_sndbuf)
  		return false;
  
  	return sk->sk_prot->stream_memory_free ?
  		sk->sk_prot->stream_memory_free(sk) : true;
  }

  static inline bool sk_stream_is_writeable(const struct sock *sk)
  {

  	return sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) &&
  	       sk_stream_memory_free(sk);

  }

  static inline int sk_under_cgroup_hierarchy(struct sock *sk,
  					    struct cgroup *ancestor)
  {
  #ifdef CONFIG_SOCK_CGROUP_DATA
  	return cgroup_is_descendant(sock_cgroup_ptr(&sk->sk_cgrp_data),
  				    ancestor);
  #else
  	return -ENOTSUPP;
  #endif
  }

  static inline bool sk_has_memory_pressure(const struct sock *sk)
  {
  	return sk->sk_prot->memory_pressure != NULL;
  }
  
  static inline bool sk_under_memory_pressure(const struct sock *sk)
  {
  	if (!sk->sk_prot->memory_pressure)
  		return false;

  	if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
  	    mem_cgroup_under_socket_pressure(sk->sk_memcg))

  		return true;

  	return !!*sk->sk_prot->memory_pressure;

  }

  static inline long
  sk_memory_allocated(const struct sock *sk)
  {

  	return atomic_long_read(sk->sk_prot->memory_allocated);

  }
  
  static inline long

  sk_memory_allocated_add(struct sock *sk, int amt)

  {

  	return atomic_long_add_return(amt, sk->sk_prot->memory_allocated);

  }
  
  static inline void

  sk_memory_allocated_sub(struct sock *sk, int amt)

  {

  	atomic_long_sub(amt, sk->sk_prot->memory_allocated);

  }
  
  static inline void sk_sockets_allocated_dec(struct sock *sk)
  {

  	percpu_counter_dec(sk->sk_prot->sockets_allocated);

  }
  
  static inline void sk_sockets_allocated_inc(struct sock *sk)
  {

  	percpu_counter_inc(sk->sk_prot->sockets_allocated);

  }
  
  static inline int
  sk_sockets_allocated_read_positive(struct sock *sk)
  {

  	return percpu_counter_read_positive(sk->sk_prot->sockets_allocated);

  }
  
  static inline int
  proto_sockets_allocated_sum_positive(struct proto *prot)
  {
  	return percpu_counter_sum_positive(prot->sockets_allocated);
  }
  
  static inline long
  proto_memory_allocated(struct proto *prot)
  {
  	return atomic_long_read(prot->memory_allocated);
  }
  
  static inline bool
  proto_memory_pressure(struct proto *prot)
  {
  	if (!prot->memory_pressure)
  		return false;
  	return !!*prot->memory_pressure;
  }

  
  #ifdef CONFIG_PROC_FS

  /* Called with local bh disabled */

  void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
  int sock_prot_inuse_get(struct net *net, struct proto *proto);

  #else

  static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,

  		int inc)

  {
  }

  #endif

  /* With per-bucket locks this operation is not-atomic, so that
   * this version is not worse.
   */

  static inline int __sk_prot_rehash(struct sock *sk)

  {
  	sk->sk_prot->unhash(sk);

  	return sk->sk_prot->hash(sk);

  }

  /* About 10 seconds */
  #define SOCK_DESTROY_TIME (10*HZ)
  
  /* Sockets 0-1023 can't be bound to unless you are superuser */
  #define PROT_SOCK	1024
  
  #define SHUTDOWN_MASK	3
  #define RCV_SHUTDOWN	1
  #define SEND_SHUTDOWN	2
  
  #define SOCK_SNDBUF_LOCK	1
  #define SOCK_RCVBUF_LOCK	2
  #define SOCK_BINDADDR_LOCK	4
  #define SOCK_BINDPORT_LOCK	8

  struct socket_alloc {
  	struct socket socket;
  	struct inode vfs_inode;
  };
  
  static inline struct socket *SOCKET_I(struct inode *inode)
  {
  	return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
  }
  
  static inline struct inode *SOCK_INODE(struct socket *socket)
  {
  	return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
  }

  /*
   * Functions for memory accounting
   */

  int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind);

  int __sk_mem_schedule(struct sock *sk, int size, int kind);

  void __sk_mem_reduce_allocated(struct sock *sk, int amount);

  void __sk_mem_reclaim(struct sock *sk, int amount);

  /* We used to have PAGE_SIZE here, but systems with 64KB pages
   * do not necessarily have 16x time more memory than 4KB ones.
   */
  #define SK_MEM_QUANTUM 4096

  #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
  #define SK_MEM_SEND	0
  #define SK_MEM_RECV	1

  /* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
  static inline long sk_prot_mem_limits(const struct sock *sk, int index)
  {
  	long val = sk->sk_prot->sysctl_mem[index];
  
  #if PAGE_SIZE > SK_MEM_QUANTUM
  	val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
  #elif PAGE_SIZE < SK_MEM_QUANTUM
  	val >>= SK_MEM_QUANTUM_SHIFT - PAGE_SHIFT;
  #endif
  	return val;
  }

  static inline int sk_mem_pages(int amt)

  {

  	return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;

  }

  static inline bool sk_has_account(struct sock *sk)

  {

  	/* return true if protocol supports memory accounting */
  	return !!sk->sk_prot->memory_allocated;

  }

  static inline bool sk_wmem_schedule(struct sock *sk, int size)

  {

  	if (!sk_has_account(sk))

  		return true;

  	return size <= sk->sk_forward_alloc ||
  		__sk_mem_schedule(sk, size, SK_MEM_SEND);

  }

  static inline bool

  sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)

  {

  	if (!sk_has_account(sk))

  		return true;

  	return size<= sk->sk_forward_alloc ||
  		__sk_mem_schedule(sk, size, SK_MEM_RECV) ||
  		skb_pfmemalloc(skb);

  }
  
  static inline void sk_mem_reclaim(struct sock *sk)
  {
  	if (!sk_has_account(sk))
  		return;
  	if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)

  		__sk_mem_reclaim(sk, sk->sk_forward_alloc);

  }

  static inline void sk_mem_reclaim_partial(struct sock *sk)
  {
  	if (!sk_has_account(sk))
  		return;
  	if (sk->sk_forward_alloc > SK_MEM_QUANTUM)

  		__sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);

  }

  static inline void sk_mem_charge(struct sock *sk, int size)
  {
  	if (!sk_has_account(sk))
  		return;
  	sk->sk_forward_alloc -= size;
  }
  
  static inline void sk_mem_uncharge(struct sock *sk, int size)
  {
  	if (!sk_has_account(sk))
  		return;
  	sk->sk_forward_alloc += size;

  
  	/* Avoid a possible overflow.
  	 * TCP send queues can make this happen, if sk_mem_reclaim()
  	 * is not called and more than 2 GBytes are released at once.
  	 *
  	 * If we reach 2 MBytes, reclaim 1 MBytes right now, there is
  	 * no need to hold that much forward allocation anyway.
  	 */
  	if (unlikely(sk->sk_forward_alloc >= 1 << 21))
  		__sk_mem_reclaim(sk, 1 << 20);

  }
  
  static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
  {

  	sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
  	sk->sk_wmem_queued -= skb->truesize;
  	sk_mem_uncharge(sk, skb->truesize);
  	__kfree_skb(skb);

  }

  static inline void sock_release_ownership(struct sock *sk)
  {

  	if (sk->sk_lock.owned) {
  		sk->sk_lock.owned = 0;
  
  		/* The sk_lock has mutex_unlock() semantics: */
  		mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
  	}

  }

  /*
   * Macro so as to not evaluate some arguments when
   * lockdep is not enabled.
   *
   * Mark both the sk_lock and the sk_lock.slock as a
   * per-address-family lock class.
   */

  #define sock_lock_init_class_and_name(sk, sname, skey, name, key)	\

  do {									\

  	sk->sk_lock.owned = 0;						\

  	init_waitqueue_head(&sk->sk_lock.wq);				\
  	spin_lock_init(&(sk)->sk_lock.slock);				\
  	debug_check_no_locks_freed((void *)&(sk)->sk_lock,		\
  			sizeof((sk)->sk_lock));				\
  	lockdep_set_class_and_name(&(sk)->sk_lock.slock,		\

  				(skey), (sname));				\

  	lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);	\
  } while (0)

  #ifdef CONFIG_LOCKDEP

  static inline bool lockdep_sock_is_held(const struct sock *csk)

  {
  	struct sock *sk = (struct sock *)csk;
  
  	return lockdep_is_held(&sk->sk_lock) ||
  	       lockdep_is_held(&sk->sk_lock.slock);
  }

  #endif

  void lock_sock_nested(struct sock *sk, int subclass);

  
  static inline void lock_sock(struct sock *sk)
  {
  	lock_sock_nested(sk, 0);
  }

  void __release_sock(struct sock *sk);

  void release_sock(struct sock *sk);

  
  /* BH context may only use the following locking interface. */
  #define bh_lock_sock(__sk)	spin_lock(&((__sk)->sk_lock.slock))

  #define bh_lock_sock_nested(__sk) \
  				spin_lock_nested(&((__sk)->sk_lock.slock), \
  				SINGLE_DEPTH_NESTING)

  #define bh_unlock_sock(__sk)	spin_unlock(&((__sk)->sk_lock.slock))

  bool lock_sock_fast(struct sock *sk);

  /**
   * unlock_sock_fast - complement of lock_sock_fast
   * @sk: socket
   * @slow: slow mode
   *
   * fast unlock socket for user context.
   * If slow mode is on, we call regular release_sock()
   */
  static inline void unlock_sock_fast(struct sock *sk, bool slow)