linux/include/net/sock.h
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   1/*
   2 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3 *              operating system.  INET is implemented using the  BSD Socket
   4 *              interface as the means of communication with the user level.
   5 *
   6 *              Definitions for the AF_INET socket handler.
   7 *
   8 * Version:     @(#)sock.h      1.0.4   05/13/93
   9 *
  10 * Authors:     Ross Biro
  11 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12 *              Corey Minyard <wf-rch!minyard@relay.EU.net>
  13 *              Florian La Roche <flla@stud.uni-sb.de>
  14 *
  15 * Fixes:
  16 *              Alan Cox        :       Volatiles in skbuff pointers. See
  17 *                                      skbuff comments. May be overdone,
  18 *                                      better to prove they can be removed
  19 *                                      than the reverse.
  20 *              Alan Cox        :       Added a zapped field for tcp to note
  21 *                                      a socket is reset and must stay shut up
  22 *              Alan Cox        :       New fields for options
  23 *      Pauline Middelink       :       identd support
  24 *              Alan Cox        :       Eliminate low level recv/recvfrom
  25 *              David S. Miller :       New socket lookup architecture.
  26 *              Steve Whitehouse:       Default routines for sock_ops
  27 *              Arnaldo C. Melo :       removed net_pinfo, tp_pinfo and made
  28 *                                      protinfo be just a void pointer, as the
  29 *                                      protocol specific parts were moved to
  30 *                                      respective headers and ipv4/v6, etc now
  31 *                                      use private slabcaches for its socks
  32 *              Pedro Hortas    :       New flags field for socket options
  33 *
  34 *
  35 *              This program is free software; you can redistribute it and/or
  36 *              modify it under the terms of the GNU General Public License
  37 *              as published by the Free Software Foundation; either version
  38 *              2 of the License, or (at your option) any later version.
  39 */
  40#ifndef _SOCK_H
  41#define _SOCK_H
  42
  43#include <linux/hardirq.h>
  44#include <linux/kernel.h>
  45#include <linux/list.h>
  46#include <linux/list_nulls.h>
  47#include <linux/timer.h>
  48#include <linux/cache.h>
  49#include <linux/bitops.h>
  50#include <linux/lockdep.h>
  51#include <linux/netdevice.h>
  52#include <linux/skbuff.h>       /* struct sk_buff */
  53#include <linux/mm.h>
  54#include <linux/security.h>
  55#include <linux/slab.h>
  56#include <linux/uaccess.h>
  57#include <linux/memcontrol.h>
  58#include <linux/res_counter.h>
  59#include <linux/static_key.h>
  60#include <linux/aio.h>
  61#include <linux/sched.h>
  62
  63#include <linux/filter.h>
  64#include <linux/rculist_nulls.h>
  65#include <linux/poll.h>
  66
  67#include <linux/atomic.h>
  68#include <net/dst.h>
  69#include <net/checksum.h>
  70
  71struct cgroup;
  72struct cgroup_subsys;
  73#ifdef CONFIG_NET
  74int mem_cgroup_sockets_init(struct mem_cgroup *memcg, struct cgroup_subsys *ss);
  75void mem_cgroup_sockets_destroy(struct mem_cgroup *memcg);
  76#else
  77static inline
  78int mem_cgroup_sockets_init(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
  79{
  80        return 0;
  81}
  82static inline
  83void mem_cgroup_sockets_destroy(struct mem_cgroup *memcg)
  84{
  85}
  86#endif
  87/*
  88 * This structure really needs to be cleaned up.
  89 * Most of it is for TCP, and not used by any of
  90 * the other protocols.
  91 */
  92
  93/* Define this to get the SOCK_DBG debugging facility. */
  94#define SOCK_DEBUGGING
  95#ifdef SOCK_DEBUGGING
  96#define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
  97                                        printk(KERN_DEBUG msg); } while (0)
  98#else
  99/* Validate arguments and do nothing */
 100static inline __printf(2, 3)
 101void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)
 102{
 103}
 104#endif
 105
 106/* This is the per-socket lock.  The spinlock provides a synchronization
 107 * between user contexts and software interrupt processing, whereas the
 108 * mini-semaphore synchronizes multiple users amongst themselves.
 109 */
 110typedef struct {
 111        spinlock_t              slock;
 112        int                     owned;
 113        wait_queue_head_t       wq;
 114        /*
 115         * We express the mutex-alike socket_lock semantics
 116         * to the lock validator by explicitly managing
 117         * the slock as a lock variant (in addition to
 118         * the slock itself):
 119         */
 120#ifdef CONFIG_DEBUG_LOCK_ALLOC
 121        struct lockdep_map dep_map;
 122#endif
 123} socket_lock_t;
 124
 125struct sock;
 126struct proto;
 127struct net;
 128
 129/**
 130 *      struct sock_common - minimal network layer representation of sockets
 131 *      @skc_daddr: Foreign IPv4 addr
 132 *      @skc_rcv_saddr: Bound local IPv4 addr
 133 *      @skc_hash: hash value used with various protocol lookup tables
 134 *      @skc_u16hashes: two u16 hash values used by UDP lookup tables
 135 *      @skc_family: network address family
 136 *      @skc_state: Connection state
 137 *      @skc_reuse: %SO_REUSEADDR setting
 138 *      @skc_bound_dev_if: bound device index if != 0
 139 *      @skc_bind_node: bind hash linkage for various protocol lookup tables
 140 *      @skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
 141 *      @skc_prot: protocol handlers inside a network family
 142 *      @skc_net: reference to the network namespace of this socket
 143 *      @skc_node: main hash linkage for various protocol lookup tables
 144 *      @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
 145 *      @skc_tx_queue_mapping: tx queue number for this connection
 146 *      @skc_refcnt: reference count
 147 *
 148 *      This is the minimal network layer representation of sockets, the header
 149 *      for struct sock and struct inet_timewait_sock.
 150 */
 151struct sock_common {
 152        /* skc_daddr and skc_rcv_saddr must be grouped :
 153         * cf INET_MATCH() and INET_TW_MATCH()
 154         */
 155        __be32                  skc_daddr;
 156        __be32                  skc_rcv_saddr;
 157
 158        union  {
 159                unsigned int    skc_hash;
 160                __u16           skc_u16hashes[2];
 161        };
 162        unsigned short          skc_family;
 163        volatile unsigned char  skc_state;
 164        unsigned char           skc_reuse;
 165        int                     skc_bound_dev_if;
 166        union {
 167                struct hlist_node       skc_bind_node;
 168                struct hlist_nulls_node skc_portaddr_node;
 169        };
 170        struct proto            *skc_prot;
 171#ifdef CONFIG_NET_NS
 172        struct net              *skc_net;
 173#endif
 174        /*
 175         * fields between dontcopy_begin/dontcopy_end
 176         * are not copied in sock_copy()
 177         */
 178        /* private: */
 179        int                     skc_dontcopy_begin[0];
 180        /* public: */
 181        union {
 182                struct hlist_node       skc_node;
 183                struct hlist_nulls_node skc_nulls_node;
 184        };
 185        int                     skc_tx_queue_mapping;
 186        atomic_t                skc_refcnt;
 187        /* private: */
 188        int                     skc_dontcopy_end[0];
 189        /* public: */
 190};
 191
 192struct cg_proto;
 193/**
 194  *     struct sock - network layer representation of sockets
 195  *     @__sk_common: shared layout with inet_timewait_sock
 196  *     @sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
 197  *     @sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
 198  *     @sk_lock:       synchronizer
 199  *     @sk_rcvbuf: size of receive buffer in bytes
 200  *     @sk_wq: sock wait queue and async head
 201  *     @sk_rx_dst: receive input route used by early tcp demux
 202  *     @sk_dst_cache: destination cache
 203  *     @sk_dst_lock: destination cache lock
 204  *     @sk_policy: flow policy
 205  *     @sk_receive_queue: incoming packets
 206  *     @sk_wmem_alloc: transmit queue bytes committed
 207  *     @sk_write_queue: Packet sending queue
 208  *     @sk_async_wait_queue: DMA copied packets
 209  *     @sk_omem_alloc: "o" is "option" or "other"
 210  *     @sk_wmem_queued: persistent queue size
 211  *     @sk_forward_alloc: space allocated forward
 212  *     @sk_allocation: allocation mode
 213  *     @sk_sndbuf: size of send buffer in bytes
 214  *     @sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
 215  *                %SO_OOBINLINE settings, %SO_TIMESTAMPING settings
 216  *     @sk_no_check: %SO_NO_CHECK setting, wether or not checkup packets
 217  *     @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
 218  *     @sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)
 219  *     @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
 220  *     @sk_gso_max_size: Maximum GSO segment size to build
 221  *     @sk_gso_max_segs: Maximum number of GSO segments
 222  *     @sk_lingertime: %SO_LINGER l_linger setting
 223  *     @sk_backlog: always used with the per-socket spinlock held
 224  *     @sk_callback_lock: used with the callbacks in the end of this struct
 225  *     @sk_error_queue: rarely used
 226  *     @sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
 227  *                       IPV6_ADDRFORM for instance)
 228  *     @sk_err: last error
 229  *     @sk_err_soft: errors that don't cause failure but are the cause of a
 230  *                   persistent failure not just 'timed out'
 231  *     @sk_drops: raw/udp drops counter
 232  *     @sk_ack_backlog: current listen backlog
 233  *     @sk_max_ack_backlog: listen backlog set in listen()
 234  *     @sk_priority: %SO_PRIORITY setting
 235  *     @sk_cgrp_prioidx: socket group's priority map index
 236  *     @sk_type: socket type (%SOCK_STREAM, etc)
 237  *     @sk_protocol: which protocol this socket belongs in this network family
 238  *     @sk_peer_pid: &struct pid for this socket's peer
 239  *     @sk_peer_cred: %SO_PEERCRED setting
 240  *     @sk_rcvlowat: %SO_RCVLOWAT setting
 241  *     @sk_rcvtimeo: %SO_RCVTIMEO setting
 242  *     @sk_sndtimeo: %SO_SNDTIMEO setting
 243  *     @sk_rxhash: flow hash received from netif layer
 244  *     @sk_filter: socket filtering instructions
 245  *     @sk_protinfo: private area, net family specific, when not using slab
 246  *     @sk_timer: sock cleanup timer
 247  *     @sk_stamp: time stamp of last packet received
 248  *     @sk_socket: Identd and reporting IO signals
 249  *     @sk_user_data: RPC layer private data
 250  *     @sk_sndmsg_page: cached page for sendmsg
 251  *     @sk_sndmsg_off: cached offset for sendmsg
 252  *     @sk_peek_off: current peek_offset value
 253  *     @sk_send_head: front of stuff to transmit
 254  *     @sk_security: used by security modules
 255  *     @sk_mark: generic packet mark
 256  *     @sk_classid: this socket's cgroup classid
 257  *     @sk_cgrp: this socket's cgroup-specific proto data
 258  *     @sk_write_pending: a write to stream socket waits to start
 259  *     @sk_state_change: callback to indicate change in the state of the sock
 260  *     @sk_data_ready: callback to indicate there is data to be processed
 261  *     @sk_write_space: callback to indicate there is bf sending space available
 262  *     @sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
 263  *     @sk_backlog_rcv: callback to process the backlog
 264  *     @sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
 265 */
 266struct sock {
 267        /*
 268         * Now struct inet_timewait_sock also uses sock_common, so please just
 269         * don't add nothing before this first member (__sk_common) --acme
 270         */
 271        struct sock_common      __sk_common;
 272#define sk_node                 __sk_common.skc_node
 273#define sk_nulls_node           __sk_common.skc_nulls_node
 274#define sk_refcnt               __sk_common.skc_refcnt
 275#define sk_tx_queue_mapping     __sk_common.skc_tx_queue_mapping
 276
 277#define sk_dontcopy_begin       __sk_common.skc_dontcopy_begin
 278#define sk_dontcopy_end         __sk_common.skc_dontcopy_end
 279#define sk_hash                 __sk_common.skc_hash
 280#define sk_family               __sk_common.skc_family
 281#define sk_state                __sk_common.skc_state
 282#define sk_reuse                __sk_common.skc_reuse
 283#define sk_bound_dev_if         __sk_common.skc_bound_dev_if
 284#define sk_bind_node            __sk_common.skc_bind_node
 285#define sk_prot                 __sk_common.skc_prot
 286#define sk_net                  __sk_common.skc_net
 287        socket_lock_t           sk_lock;
 288        struct sk_buff_head     sk_receive_queue;
 289        /*
 290         * The backlog queue is special, it is always used with
 291         * the per-socket spinlock held and requires low latency
 292         * access. Therefore we special case it's implementation.
 293         * Note : rmem_alloc is in this structure to fill a hole
 294         * on 64bit arches, not because its logically part of
 295         * backlog.
 296         */
 297        struct {
 298                atomic_t        rmem_alloc;
 299                int             len;
 300                struct sk_buff  *head;
 301                struct sk_buff  *tail;
 302        } sk_backlog;
 303#define sk_rmem_alloc sk_backlog.rmem_alloc
 304        int                     sk_forward_alloc;
 305#ifdef CONFIG_RPS
 306        __u32                   sk_rxhash;
 307#endif
 308        atomic_t                sk_drops;
 309        int                     sk_rcvbuf;
 310
 311        struct sk_filter __rcu  *sk_filter;
 312        struct socket_wq __rcu  *sk_wq;
 313
 314#ifdef CONFIG_NET_DMA
 315        struct sk_buff_head     sk_async_wait_queue;
 316#endif
 317
 318#ifdef CONFIG_XFRM
 319        struct xfrm_policy      *sk_policy[2];
 320#endif
 321        unsigned long           sk_flags;
 322        struct dst_entry        *sk_rx_dst;
 323        struct dst_entry        *sk_dst_cache;
 324        spinlock_t              sk_dst_lock;
 325        atomic_t                sk_wmem_alloc;
 326        atomic_t                sk_omem_alloc;
 327        int                     sk_sndbuf;
 328        struct sk_buff_head     sk_write_queue;
 329        kmemcheck_bitfield_begin(flags);
 330        unsigned int            sk_shutdown  : 2,
 331                                sk_no_check  : 2,
 332                                sk_userlocks : 4,
 333                                sk_protocol  : 8,
 334                                sk_type      : 16;
 335        kmemcheck_bitfield_end(flags);
 336        int                     sk_wmem_queued;
 337        gfp_t                   sk_allocation;
 338        netdev_features_t       sk_route_caps;
 339        netdev_features_t       sk_route_nocaps;
 340        int                     sk_gso_type;
 341        unsigned int            sk_gso_max_size;
 342        u16                     sk_gso_max_segs;
 343        int                     sk_rcvlowat;
 344        unsigned long           sk_lingertime;
 345        struct sk_buff_head     sk_error_queue;
 346        struct proto            *sk_prot_creator;
 347        rwlock_t                sk_callback_lock;
 348        int                     sk_err,
 349                                sk_err_soft;
 350        unsigned short          sk_ack_backlog;
 351        unsigned short          sk_max_ack_backlog;
 352        __u32                   sk_priority;
 353#ifdef CONFIG_CGROUPS
 354        __u32                   sk_cgrp_prioidx;
 355#endif
 356        struct pid              *sk_peer_pid;
 357        const struct cred       *sk_peer_cred;
 358        long                    sk_rcvtimeo;
 359        long                    sk_sndtimeo;
 360        void                    *sk_protinfo;
 361        struct timer_list       sk_timer;
 362        ktime_t                 sk_stamp;
 363        struct socket           *sk_socket;
 364        void                    *sk_user_data;
 365        struct page             *sk_sndmsg_page;
 366        struct sk_buff          *sk_send_head;
 367        __u32                   sk_sndmsg_off;
 368        __s32                   sk_peek_off;
 369        int                     sk_write_pending;
 370#ifdef CONFIG_SECURITY
 371        void                    *sk_security;
 372#endif
 373        __u32                   sk_mark;
 374        u32                     sk_classid;
 375        struct cg_proto         *sk_cgrp;
 376        void                    (*sk_state_change)(struct sock *sk);
 377        void                    (*sk_data_ready)(struct sock *sk, int bytes);
 378        void                    (*sk_write_space)(struct sock *sk);
 379        void                    (*sk_error_report)(struct sock *sk);
 380        int                     (*sk_backlog_rcv)(struct sock *sk,
 381                                                  struct sk_buff *skb);
 382        void                    (*sk_destruct)(struct sock *sk);
 383};
 384
 385/*
 386 * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
 387 * or not whether his port will be reused by someone else. SK_FORCE_REUSE
 388 * on a socket means that the socket will reuse everybody else's port
 389 * without looking at the other's sk_reuse value.
 390 */
 391
 392#define SK_NO_REUSE     0
 393#define SK_CAN_REUSE    1
 394#define SK_FORCE_REUSE  2
 395
 396static inline int sk_peek_offset(struct sock *sk, int flags)
 397{
 398        if ((flags & MSG_PEEK) && (sk->sk_peek_off >= 0))
 399                return sk->sk_peek_off;
 400        else
 401                return 0;
 402}
 403
 404static inline void sk_peek_offset_bwd(struct sock *sk, int val)
 405{
 406        if (sk->sk_peek_off >= 0) {
 407                if (sk->sk_peek_off >= val)
 408                        sk->sk_peek_off -= val;
 409                else
 410                        sk->sk_peek_off = 0;
 411        }
 412}
 413
 414static inline void sk_peek_offset_fwd(struct sock *sk, int val)
 415{
 416        if (sk->sk_peek_off >= 0)
 417                sk->sk_peek_off += val;
 418}
 419
 420/*
 421 * Hashed lists helper routines
 422 */
 423static inline struct sock *sk_entry(const struct hlist_node *node)
 424{
 425        return hlist_entry(node, struct sock, sk_node);
 426}
 427
 428static inline struct sock *__sk_head(const struct hlist_head *head)
 429{
 430        return hlist_entry(head->first, struct sock, sk_node);
 431}
 432
 433static inline struct sock *sk_head(const struct hlist_head *head)
 434{
 435        return hlist_empty(head) ? NULL : __sk_head(head);
 436}
 437
 438static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
 439{
 440        return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
 441}
 442
 443static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
 444{
 445        return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
 446}
 447
 448static inline struct sock *sk_next(const struct sock *sk)
 449{
 450        return sk->sk_node.next ?
 451                hlist_entry(sk->sk_node.next, struct sock, sk_node) : NULL;
 452}
 453
 454static inline struct sock *sk_nulls_next(const struct sock *sk)
 455{
 456        return (!is_a_nulls(sk->sk_nulls_node.next)) ?
 457                hlist_nulls_entry(sk->sk_nulls_node.next,
 458                                  struct sock, sk_nulls_node) :
 459                NULL;
 460}
 461
 462static inline bool sk_unhashed(const struct sock *sk)
 463{
 464        return hlist_unhashed(&sk->sk_node);
 465}
 466
 467static inline bool sk_hashed(const struct sock *sk)
 468{
 469        return !sk_unhashed(sk);
 470}
 471
 472static inline void sk_node_init(struct hlist_node *node)
 473{
 474        node->pprev = NULL;
 475}
 476
 477static inline void sk_nulls_node_init(struct hlist_nulls_node *node)
 478{
 479        node->pprev = NULL;
 480}
 481
 482static inline void __sk_del_node(struct sock *sk)
 483{
 484        __hlist_del(&sk->sk_node);
 485}
 486
 487/* NB: equivalent to hlist_del_init_rcu */
 488static inline bool __sk_del_node_init(struct sock *sk)
 489{
 490        if (sk_hashed(sk)) {
 491                __sk_del_node(sk);
 492                sk_node_init(&sk->sk_node);
 493                return true;
 494        }
 495        return false;
 496}
 497
 498/* Grab socket reference count. This operation is valid only
 499   when sk is ALREADY grabbed f.e. it is found in hash table
 500   or a list and the lookup is made under lock preventing hash table
 501   modifications.
 502 */
 503
 504static inline void sock_hold(struct sock *sk)
 505{
 506        atomic_inc(&sk->sk_refcnt);
 507}
 508
 509/* Ungrab socket in the context, which assumes that socket refcnt
 510   cannot hit zero, f.e. it is true in context of any socketcall.
 511 */
 512static inline void __sock_put(struct sock *sk)
 513{
 514        atomic_dec(&sk->sk_refcnt);
 515}
 516
 517static inline bool sk_del_node_init(struct sock *sk)
 518{
 519        bool rc = __sk_del_node_init(sk);
 520
 521        if (rc) {
 522                /* paranoid for a while -acme */
 523                WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
 524                __sock_put(sk);
 525        }
 526        return rc;
 527}
 528#define sk_del_node_init_rcu(sk)        sk_del_node_init(sk)
 529
 530static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)
 531{
 532        if (sk_hashed(sk)) {
 533                hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
 534                return true;
 535        }
 536        return false;
 537}
 538
 539static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
 540{
 541        bool rc = __sk_nulls_del_node_init_rcu(sk);
 542
 543        if (rc) {
 544                /* paranoid for a while -acme */
 545                WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
 546                __sock_put(sk);
 547        }
 548        return rc;
 549}
 550
 551static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)
 552{
 553        hlist_add_head(&sk->sk_node, list);
 554}
 555
 556static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
 557{
 558        sock_hold(sk);
 559        __sk_add_node(sk, list);
 560}
 561
 562static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
 563{
 564        sock_hold(sk);
 565        hlist_add_head_rcu(&sk->sk_node, list);
 566}
 567
 568static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
 569{
 570        hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
 571}
 572
 573static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
 574{
 575        sock_hold(sk);
 576        __sk_nulls_add_node_rcu(sk, list);
 577}
 578
 579static inline void __sk_del_bind_node(struct sock *sk)
 580{
 581        __hlist_del(&sk->sk_bind_node);
 582}
 583
 584static inline void sk_add_bind_node(struct sock *sk,
 585                                        struct hlist_head *list)
 586{
 587        hlist_add_head(&sk->sk_bind_node, list);
 588}
 589
 590#define sk_for_each(__sk, node, list) \
 591        hlist_for_each_entry(__sk, node, list, sk_node)
 592#define sk_for_each_rcu(__sk, node, list) \
 593        hlist_for_each_entry_rcu(__sk, node, list, sk_node)
 594#define sk_nulls_for_each(__sk, node, list) \
 595        hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
 596#define sk_nulls_for_each_rcu(__sk, node, list) \
 597        hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
 598#define sk_for_each_from(__sk, node) \
 599        if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
 600                hlist_for_each_entry_from(__sk, node, sk_node)
 601#define sk_nulls_for_each_from(__sk, node) \
 602        if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
 603                hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
 604#define sk_for_each_safe(__sk, node, tmp, list) \
 605        hlist_for_each_entry_safe(__sk, node, tmp, list, sk_node)
 606#define sk_for_each_bound(__sk, node, list) \
 607        hlist_for_each_entry(__sk, node, list, sk_bind_node)
 608
 609/* Sock flags */
 610enum sock_flags {
 611        SOCK_DEAD,
 612        SOCK_DONE,
 613        SOCK_URGINLINE,
 614        SOCK_KEEPOPEN,
 615        SOCK_LINGER,
 616        SOCK_DESTROY,
 617        SOCK_BROADCAST,
 618        SOCK_TIMESTAMP,
 619        SOCK_ZAPPED,
 620        SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
 621        SOCK_DBG, /* %SO_DEBUG setting */
 622        SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
 623        SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
 624        SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
 625        SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
 626        SOCK_MEMALLOC, /* VM depends on this socket for swapping */
 627        SOCK_TIMESTAMPING_TX_HARDWARE,  /* %SOF_TIMESTAMPING_TX_HARDWARE */
 628        SOCK_TIMESTAMPING_TX_SOFTWARE,  /* %SOF_TIMESTAMPING_TX_SOFTWARE */
 629        SOCK_TIMESTAMPING_RX_HARDWARE,  /* %SOF_TIMESTAMPING_RX_HARDWARE */
 630        SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
 631        SOCK_TIMESTAMPING_SOFTWARE,     /* %SOF_TIMESTAMPING_SOFTWARE */
 632        SOCK_TIMESTAMPING_RAW_HARDWARE, /* %SOF_TIMESTAMPING_RAW_HARDWARE */
 633        SOCK_TIMESTAMPING_SYS_HARDWARE, /* %SOF_TIMESTAMPING_SYS_HARDWARE */
 634        SOCK_FASYNC, /* fasync() active */
 635        SOCK_RXQ_OVFL,
 636        SOCK_ZEROCOPY, /* buffers from userspace */
 637        SOCK_WIFI_STATUS, /* push wifi status to userspace */
 638        SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
 639                     * Will use last 4 bytes of packet sent from
 640                     * user-space instead.
 641                     */
 642};
 643
 644static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
 645{
 646        nsk->sk_flags = osk->sk_flags;
 647}
 648
 649static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
 650{
 651        __set_bit(flag, &sk->sk_flags);
 652}
 653
 654static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
 655{
 656        __clear_bit(flag, &sk->sk_flags);
 657}
 658
 659static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
 660{
 661        return test_bit(flag, &sk->sk_flags);
 662}
 663
 664#ifdef CONFIG_NET
 665extern struct static_key memalloc_socks;
 666static inline int sk_memalloc_socks(void)
 667{
 668        return static_key_false(&memalloc_socks);
 669}
 670#else
 671
 672static inline int sk_memalloc_socks(void)
 673{
 674        return 0;
 675}
 676
 677#endif
 678
 679static inline gfp_t sk_gfp_atomic(struct sock *sk, gfp_t gfp_mask)
 680{
 681        return GFP_ATOMIC | (sk->sk_allocation & __GFP_MEMALLOC);
 682}
 683
 684static inline void sk_acceptq_removed(struct sock *sk)
 685{
 686        sk->sk_ack_backlog--;
 687}
 688
 689static inline void sk_acceptq_added(struct sock *sk)
 690{
 691        sk->sk_ack_backlog++;
 692}
 693
 694static inline bool sk_acceptq_is_full(const struct sock *sk)
 695{
 696        return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
 697}
 698
 699/*
 700 * Compute minimal free write space needed to queue new packets.
 701 */
 702static inline int sk_stream_min_wspace(const struct sock *sk)
 703{
 704        return sk->sk_wmem_queued >> 1;
 705}
 706
 707static inline int sk_stream_wspace(const struct sock *sk)
 708{
 709        return sk->sk_sndbuf - sk->sk_wmem_queued;
 710}
 711
 712extern void sk_stream_write_space(struct sock *sk);
 713
 714static inline bool sk_stream_memory_free(const struct sock *sk)
 715{
 716        return sk->sk_wmem_queued < sk->sk_sndbuf;
 717}
 718
 719/* OOB backlog add */
 720static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
 721{
 722        /* dont let skb dst not refcounted, we are going to leave rcu lock */
 723        skb_dst_force(skb);
 724
 725        if (!sk->sk_backlog.tail)
 726                sk->sk_backlog.head = skb;
 727        else
 728                sk->sk_backlog.tail->next = skb;
 729
 730        sk->sk_backlog.tail = skb;
 731        skb->next = NULL;
 732}
 733
 734/*
 735 * Take into account size of receive queue and backlog queue
 736 * Do not take into account this skb truesize,
 737 * to allow even a single big packet to come.
 738 */
 739static inline bool sk_rcvqueues_full(const struct sock *sk, const struct sk_buff *skb,
 740                                     unsigned int limit)
 741{
 742        unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
 743
 744        return qsize > limit;
 745}
 746
 747/* The per-socket spinlock must be held here. */
 748static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
 749                                              unsigned int limit)
 750{
 751        if (sk_rcvqueues_full(sk, skb, limit))
 752                return -ENOBUFS;
 753
 754        __sk_add_backlog(sk, skb);
 755        sk->sk_backlog.len += skb->truesize;
 756        return 0;
 757}
 758
 759extern int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
 760
 761static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 762{
 763        if (sk_memalloc_socks() && skb_pfmemalloc(skb))
 764                return __sk_backlog_rcv(sk, skb);
 765
 766        return sk->sk_backlog_rcv(sk, skb);
 767}
 768
 769static inline void sock_rps_record_flow(const struct sock *sk)
 770{
 771#ifdef CONFIG_RPS
 772        struct rps_sock_flow_table *sock_flow_table;
 773
 774        rcu_read_lock();
 775        sock_flow_table = rcu_dereference(rps_sock_flow_table);
 776        rps_record_sock_flow(sock_flow_table, sk->sk_rxhash);
 777        rcu_read_unlock();
 778#endif
 779}
 780
 781static inline void sock_rps_reset_flow(const struct sock *sk)
 782{
 783#ifdef CONFIG_RPS
 784        struct rps_sock_flow_table *sock_flow_table;
 785
 786        rcu_read_lock();
 787        sock_flow_table = rcu_dereference(rps_sock_flow_table);
 788        rps_reset_sock_flow(sock_flow_table, sk->sk_rxhash);
 789        rcu_read_unlock();
 790#endif
 791}
 792
 793static inline void sock_rps_save_rxhash(struct sock *sk,
 794                                        const struct sk_buff *skb)
 795{
 796#ifdef CONFIG_RPS
 797        if (unlikely(sk->sk_rxhash != skb->rxhash)) {
 798                sock_rps_reset_flow(sk);
 799                sk->sk_rxhash = skb->rxhash;
 800        }
 801#endif
 802}
 803
 804static inline void sock_rps_reset_rxhash(struct sock *sk)
 805{
 806#ifdef CONFIG_RPS
 807        sock_rps_reset_flow(sk);
 808        sk->sk_rxhash = 0;
 809#endif
 810}
 811
 812#define sk_wait_event(__sk, __timeo, __condition)                       \
 813        ({      int __rc;                                               \
 814                release_sock(__sk);                                     \
 815                __rc = __condition;                                     \
 816                if (!__rc) {                                            \
 817                        *(__timeo) = schedule_timeout(*(__timeo));      \
 818                }                                                       \
 819                lock_sock(__sk);                                        \
 820                __rc = __condition;                                     \
 821                __rc;                                                   \
 822        })
 823
 824extern int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
 825extern int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
 826extern void sk_stream_wait_close(struct sock *sk, long timeo_p);
 827extern int sk_stream_error(struct sock *sk, int flags, int err);
 828extern void sk_stream_kill_queues(struct sock *sk);
 829extern void sk_set_memalloc(struct sock *sk);
 830extern void sk_clear_memalloc(struct sock *sk);
 831
 832extern int sk_wait_data(struct sock *sk, long *timeo);
 833
 834struct request_sock_ops;
 835struct timewait_sock_ops;
 836struct inet_hashinfo;
 837struct raw_hashinfo;
 838struct module;
 839
 840/* Networking protocol blocks we attach to sockets.
 841 * socket layer -> transport layer interface
 842 * transport -> network interface is defined by struct inet_proto
 843 */
 844struct proto {
 845        void                    (*close)(struct sock *sk,
 846                                        long timeout);
 847        int                     (*connect)(struct sock *sk,
 848                                        struct sockaddr *uaddr,
 849                                        int addr_len);
 850        int                     (*disconnect)(struct sock *sk, int flags);
 851
 852        struct sock *           (*accept)(struct sock *sk, int flags, int *err);
 853
 854        int                     (*ioctl)(struct sock *sk, int cmd,
 855                                         unsigned long arg);
 856        int                     (*init)(struct sock *sk);
 857        void                    (*destroy)(struct sock *sk);
 858        void                    (*shutdown)(struct sock *sk, int how);
 859        int                     (*setsockopt)(struct sock *sk, int level,
 860                                        int optname, char __user *optval,
 861                                        unsigned int optlen);
 862        int                     (*getsockopt)(struct sock *sk, int level,
 863                                        int optname, char __user *optval,
 864                                        int __user *option);
 865#ifdef CONFIG_COMPAT
 866        int                     (*compat_setsockopt)(struct sock *sk,
 867                                        int level,
 868                                        int optname, char __user *optval,
 869                                        unsigned int optlen);
 870        int                     (*compat_getsockopt)(struct sock *sk,
 871                                        int level,
 872                                        int optname, char __user *optval,
 873                                        int __user *option);
 874        int                     (*compat_ioctl)(struct sock *sk,
 875                                        unsigned int cmd, unsigned long arg);
 876#endif
 877        int                     (*sendmsg)(struct kiocb *iocb, struct sock *sk,
 878                                           struct msghdr *msg, size_t len);
 879        int                     (*recvmsg)(struct kiocb *iocb, struct sock *sk,
 880                                           struct msghdr *msg,
 881                                           size_t len, int noblock, int flags,
 882                                           int *addr_len);
 883        int                     (*sendpage)(struct sock *sk, struct page *page,
 884                                        int offset, size_t size, int flags);
 885        int                     (*bind)(struct sock *sk,
 886                                        struct sockaddr *uaddr, int addr_len);
 887
 888        int                     (*backlog_rcv) (struct sock *sk,
 889                                                struct sk_buff *skb);
 890
 891        void            (*release_cb)(struct sock *sk);
 892        void            (*mtu_reduced)(struct sock *sk);
 893
 894        /* Keeping track of sk's, looking them up, and port selection methods. */
 895        void                    (*hash)(struct sock *sk);
 896        void                    (*unhash)(struct sock *sk);
 897        void                    (*rehash)(struct sock *sk);
 898        int                     (*get_port)(struct sock *sk, unsigned short snum);
 899        void                    (*clear_sk)(struct sock *sk, int size);
 900
 901        /* Keeping track of sockets in use */
 902#ifdef CONFIG_PROC_FS
 903        unsigned int            inuse_idx;
 904#endif
 905
 906        /* Memory pressure */
 907        void                    (*enter_memory_pressure)(struct sock *sk);
 908        atomic_long_t           *memory_allocated;      /* Current allocated memory. */
 909        struct percpu_counter   *sockets_allocated;     /* Current number of sockets. */
 910        /*
 911         * Pressure flag: try to collapse.
 912         * Technical note: it is used by multiple contexts non atomically.
 913         * All the __sk_mem_schedule() is of this nature: accounting
 914         * is strict, actions are advisory and have some latency.
 915         */
 916        int                     *memory_pressure;
 917        long                    *sysctl_mem;
 918        int                     *sysctl_wmem;
 919        int                     *sysctl_rmem;
 920        int                     max_header;
 921        bool                    no_autobind;
 922
 923        struct kmem_cache       *slab;
 924        unsigned int            obj_size;
 925        int                     slab_flags;
 926
 927        struct percpu_counter   *orphan_count;
 928
 929        struct request_sock_ops *rsk_prot;
 930        struct timewait_sock_ops *twsk_prot;
 931
 932        union {
 933                struct inet_hashinfo    *hashinfo;
 934                struct udp_table        *udp_table;
 935                struct raw_hashinfo     *raw_hash;
 936        } h;
 937
 938        struct module           *owner;
 939
 940        char                    name[32];
 941
 942        struct list_head        node;
 943#ifdef SOCK_REFCNT_DEBUG
 944        atomic_t                socks;
 945#endif
 946#ifdef CONFIG_MEMCG_KMEM
 947        /*
 948         * cgroup specific init/deinit functions. Called once for all
 949         * protocols that implement it, from cgroups populate function.
 950         * This function has to setup any files the protocol want to
 951         * appear in the kmem cgroup filesystem.
 952         */
 953        int                     (*init_cgroup)(struct mem_cgroup *memcg,
 954                                               struct cgroup_subsys *ss);
 955        void                    (*destroy_cgroup)(struct mem_cgroup *memcg);
 956        struct cg_proto         *(*proto_cgroup)(struct mem_cgroup *memcg);
 957#endif
 958};
 959
 960/*
 961 * Bits in struct cg_proto.flags
 962 */
 963enum cg_proto_flags {
 964        /* Currently active and new sockets should be assigned to cgroups */
 965        MEMCG_SOCK_ACTIVE,
 966        /* It was ever activated; we must disarm static keys on destruction */
 967        MEMCG_SOCK_ACTIVATED,
 968};
 969
 970struct cg_proto {
 971        void                    (*enter_memory_pressure)(struct sock *sk);
 972        struct res_counter      *memory_allocated;      /* Current allocated memory. */
 973        struct percpu_counter   *sockets_allocated;     /* Current number of sockets. */
 974        int                     *memory_pressure;
 975        long                    *sysctl_mem;
 976        unsigned long           flags;
 977        /*
 978         * memcg field is used to find which memcg we belong directly
 979         * Each memcg struct can hold more than one cg_proto, so container_of
 980         * won't really cut.
 981         *
 982         * The elegant solution would be having an inverse function to
 983         * proto_cgroup in struct proto, but that means polluting the structure
 984         * for everybody, instead of just for memcg users.
 985         */
 986        struct mem_cgroup       *memcg;
 987};
 988
 989extern int proto_register(struct proto *prot, int alloc_slab);
 990extern void proto_unregister(struct proto *prot);
 991
 992static inline bool memcg_proto_active(struct cg_proto *cg_proto)
 993{
 994        return test_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
 995}
 996
 997static inline bool memcg_proto_activated(struct cg_proto *cg_proto)
 998{
 999        return test_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags);
1000}
1001
1002#ifdef SOCK_REFCNT_DEBUG
1003static inline void sk_refcnt_debug_inc(struct sock *sk)
1004{
1005        atomic_inc(&sk->sk_prot->socks);
1006}
1007
1008static inline void sk_refcnt_debug_dec(struct sock *sk)
1009{
1010        atomic_dec(&sk->sk_prot->socks);
1011        printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
1012               sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
1013}
1014
1015inline void sk_refcnt_debug_release(const struct sock *sk)
1016{
1017        if (atomic_read(&sk->sk_refcnt) != 1)
1018                printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
1019                       sk->sk_prot->name, sk, atomic_read(&sk->sk_refcnt));
1020}
1021#else /* SOCK_REFCNT_DEBUG */
1022#define sk_refcnt_debug_inc(sk) do { } while (0)
1023#define sk_refcnt_debug_dec(sk) do { } while (0)
1024#define sk_refcnt_debug_release(sk) do { } while (0)
1025#endif /* SOCK_REFCNT_DEBUG */
1026
1027#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_NET)
1028extern struct static_key memcg_socket_limit_enabled;
1029static inline struct cg_proto *parent_cg_proto(struct proto *proto,
1030                                               struct cg_proto *cg_proto)
1031{
1032        return proto->proto_cgroup(parent_mem_cgroup(cg_proto->memcg));
1033}
1034#define mem_cgroup_sockets_enabled static_key_false(&memcg_socket_limit_enabled)
1035#else
1036#define mem_cgroup_sockets_enabled 0
1037static inline struct cg_proto *parent_cg_proto(struct proto *proto,
1038                                               struct cg_proto *cg_proto)
1039{
1040        return NULL;
1041}
1042#endif
1043
1044
1045static inline bool sk_has_memory_pressure(const struct sock *sk)
1046{
1047        return sk->sk_prot->memory_pressure != NULL;
1048}
1049
1050static inline bool sk_under_memory_pressure(const struct sock *sk)
1051{
1052        if (!sk->sk_prot->memory_pressure)
1053                return false;
1054
1055        if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1056                return !!*sk->sk_cgrp->memory_pressure;
1057
1058        return !!*sk->sk_prot->memory_pressure;
1059}
1060
1061static inline void sk_leave_memory_pressure(struct sock *sk)
1062{
1063        int *memory_pressure = sk->sk_prot->memory_pressure;
1064
1065        if (!memory_pressure)
1066                return;
1067
1068        if (*memory_pressure)
1069                *memory_pressure = 0;
1070
1071        if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1072                struct cg_proto *cg_proto = sk->sk_cgrp;
1073                struct proto *prot = sk->sk_prot;
1074
1075                for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1076                        if (*cg_proto->memory_pressure)
1077                                *cg_proto->memory_pressure = 0;
1078        }
1079
1080}
1081
1082static inline void sk_enter_memory_pressure(struct sock *sk)
1083{
1084        if (!sk->sk_prot->enter_memory_pressure)
1085                return;
1086
1087        if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1088                struct cg_proto *cg_proto = sk->sk_cgrp;
1089                struct proto *prot = sk->sk_prot;
1090
1091                for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1092                        cg_proto->enter_memory_pressure(sk);
1093        }
1094
1095        sk->sk_prot->enter_memory_pressure(sk);
1096}
1097
1098static inline long sk_prot_mem_limits(const struct sock *sk, int index)
1099{
1100        long *prot = sk->sk_prot->sysctl_mem;
1101        if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1102                prot = sk->sk_cgrp->sysctl_mem;
1103        return prot[index];
1104}
1105
1106static inline void memcg_memory_allocated_add(struct cg_proto *prot,
1107                                              unsigned long amt,
1108                                              int *parent_status)
1109{
1110        struct res_counter *fail;
1111        int ret;
1112
1113        ret = res_counter_charge_nofail(prot->memory_allocated,
1114                                        amt << PAGE_SHIFT, &fail);
1115        if (ret < 0)
1116                *parent_status = OVER_LIMIT;
1117}
1118
1119static inline void memcg_memory_allocated_sub(struct cg_proto *prot,
1120                                              unsigned long amt)
1121{
1122        res_counter_uncharge(prot->memory_allocated, amt << PAGE_SHIFT);
1123}
1124
1125static inline u64 memcg_memory_allocated_read(struct cg_proto *prot)
1126{
1127        u64 ret;
1128        ret = res_counter_read_u64(prot->memory_allocated, RES_USAGE);
1129        return ret >> PAGE_SHIFT;
1130}
1131
1132static inline long
1133sk_memory_allocated(const struct sock *sk)
1134{
1135        struct proto *prot = sk->sk_prot;
1136        if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1137                return memcg_memory_allocated_read(sk->sk_cgrp);
1138
1139        return atomic_long_read(prot->memory_allocated);
1140}
1141
1142static inline long
1143sk_memory_allocated_add(struct sock *sk, int amt, int *parent_status)
1144{
1145        struct proto *prot = sk->sk_prot;
1146
1147        if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1148                memcg_memory_allocated_add(sk->sk_cgrp, amt, parent_status);
1149                /* update the root cgroup regardless */
1150                atomic_long_add_return(amt, prot->memory_allocated);
1151                return memcg_memory_allocated_read(sk->sk_cgrp);
1152        }
1153
1154        return atomic_long_add_return(amt, prot->memory_allocated);
1155}
1156
1157static inline void
1158sk_memory_allocated_sub(struct sock *sk, int amt)
1159{
1160        struct proto *prot = sk->sk_prot;
1161
1162        if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1163                memcg_memory_allocated_sub(sk->sk_cgrp, amt);
1164
1165        atomic_long_sub(amt, prot->memory_allocated);
1166}
1167
1168static inline void sk_sockets_allocated_dec(struct sock *sk)
1169{
1170        struct proto *prot = sk->sk_prot;
1171
1172        if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1173                struct cg_proto *cg_proto = sk->sk_cgrp;
1174
1175                for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1176                        percpu_counter_dec(cg_proto->sockets_allocated);
1177        }
1178
1179        percpu_counter_dec(prot->sockets_allocated);
1180}
1181
1182static inline void sk_sockets_allocated_inc(struct sock *sk)
1183{
1184        struct proto *prot = sk->sk_prot;
1185
1186        if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1187                struct cg_proto *cg_proto = sk->sk_cgrp;
1188
1189                for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1190                        percpu_counter_inc(cg_proto->sockets_allocated);
1191        }
1192
1193        percpu_counter_inc(prot->sockets_allocated);
1194}
1195
1196static inline int
1197sk_sockets_allocated_read_positive(struct sock *sk)
1198{
1199        struct proto *prot = sk->sk_prot;
1200
1201        if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1202                return percpu_counter_read_positive(sk->sk_cgrp->sockets_allocated);
1203
1204        return percpu_counter_read_positive(prot->sockets_allocated);
1205}
1206
1207static inline int
1208proto_sockets_allocated_sum_positive(struct proto *prot)
1209{
1210        return percpu_counter_sum_positive(prot->sockets_allocated);
1211}
1212
1213static inline long
1214proto_memory_allocated(struct proto *prot)
1215{
1216        return atomic_long_read(prot->memory_allocated);
1217}
1218
1219static inline bool
1220proto_memory_pressure(struct proto *prot)
1221{
1222        if (!prot->memory_pressure)
1223                return false;
1224        return !!*prot->memory_pressure;
1225}
1226
1227
1228#ifdef CONFIG_PROC_FS
1229/* Called with local bh disabled */
1230extern void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
1231extern int sock_prot_inuse_get(struct net *net, struct proto *proto);
1232#else
1233static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
1234                int inc)
1235{
1236}
1237#endif
1238
1239
1240/* With per-bucket locks this operation is not-atomic, so that
1241 * this version is not worse.
1242 */
1243static inline void __sk_prot_rehash(struct sock *sk)
1244{
1245        sk->sk_prot->unhash(sk);
1246        sk->sk_prot->hash(sk);
1247}
1248
1249void sk_prot_clear_portaddr_nulls(struct sock *sk, int size);
1250
1251/* About 10 seconds */
1252#define SOCK_DESTROY_TIME (10*HZ)
1253
1254/* Sockets 0-1023 can't be bound to unless you are superuser */
1255#define PROT_SOCK       1024
1256
1257#define SHUTDOWN_MASK   3
1258#define RCV_SHUTDOWN    1
1259#define SEND_SHUTDOWN   2
1260
1261#define SOCK_SNDBUF_LOCK        1
1262#define SOCK_RCVBUF_LOCK        2
1263#define SOCK_BINDADDR_LOCK      4
1264#define SOCK_BINDPORT_LOCK      8
1265
1266/* sock_iocb: used to kick off async processing of socket ios */
1267struct sock_iocb {
1268        struct list_head        list;
1269
1270        int                     flags;
1271        int                     size;
1272        struct socket           *sock;
1273        struct sock             *sk;
1274        struct scm_cookie       *scm;
1275        struct msghdr           *msg, async_msg;
1276        struct kiocb            *kiocb;
1277};
1278
1279static inline struct sock_iocb *kiocb_to_siocb(struct kiocb *iocb)
1280{
1281        return (struct sock_iocb *)iocb->private;
1282}
1283
1284static inline struct kiocb *siocb_to_kiocb(struct sock_iocb *si)
1285{
1286        return si->kiocb;
1287}
1288
1289struct socket_alloc {
1290        struct socket socket;
1291        struct inode vfs_inode;
1292};
1293
1294static inline struct socket *SOCKET_I(struct inode *inode)
1295{
1296        return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
1297}
1298
1299static inline struct inode *SOCK_INODE(struct socket *socket)
1300{
1301        return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
1302}
1303
1304/*
1305 * Functions for memory accounting
1306 */
1307extern int __sk_mem_schedule(struct sock *sk, int size, int kind);
1308extern void __sk_mem_reclaim(struct sock *sk);
1309
1310#define SK_MEM_QUANTUM ((int)PAGE_SIZE)
1311#define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
1312#define SK_MEM_SEND     0
1313#define SK_MEM_RECV     1
1314
1315static inline int sk_mem_pages(int amt)
1316{
1317        return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
1318}
1319
1320static inline bool sk_has_account(struct sock *sk)
1321{
1322        /* return true if protocol supports memory accounting */
1323        return !!sk->sk_prot->memory_allocated;
1324}
1325
1326static inline bool sk_wmem_schedule(struct sock *sk, int size)
1327{
1328        if (!sk_has_account(sk))
1329                return true;
1330        return size <= sk->sk_forward_alloc ||
1331                __sk_mem_schedule(sk, size, SK_MEM_SEND);
1332}
1333
1334static inline bool
1335sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
1336{
1337        if (!sk_has_account(sk))
1338                return true;
1339        return size<= sk->sk_forward_alloc ||
1340                __sk_mem_schedule(sk, size, SK_MEM_RECV) ||
1341                skb_pfmemalloc(skb);
1342}
1343
1344static inline void sk_mem_reclaim(struct sock *sk)
1345{
1346        if (!sk_has_account(sk))
1347                return;
1348        if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
1349                __sk_mem_reclaim(sk);
1350}
1351
1352static inline void sk_mem_reclaim_partial(struct sock *sk)
1353{
1354        if (!sk_has_account(sk))
1355                return;
1356        if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
1357                __sk_mem_reclaim(sk);
1358}
1359
1360static inline void sk_mem_charge(struct sock *sk, int size)
1361{
1362        if (!sk_has_account(sk))
1363                return;
1364        sk->sk_forward_alloc -= size;
1365}
1366
1367static inline void sk_mem_uncharge(struct sock *sk, int size)
1368{
1369        if (!sk_has_account(sk))
1370                return;
1371        sk->sk_forward_alloc += size;
1372}
1373
1374static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
1375{
1376        sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
1377        sk->sk_wmem_queued -= skb->truesize;
1378        sk_mem_uncharge(sk, skb->truesize);
1379        __kfree_skb(skb);
1380}
1381
1382/* Used by processes to "lock" a socket state, so that
1383 * interrupts and bottom half handlers won't change it
1384 * from under us. It essentially blocks any incoming
1385 * packets, so that we won't get any new data or any
1386 * packets that change the state of the socket.
1387 *
1388 * While locked, BH processing will add new packets to
1389 * the backlog queue.  This queue is processed by the
1390 * owner of the socket lock right before it is released.
1391 *
1392 * Since ~2.3.5 it is also exclusive sleep lock serializing
1393 * accesses from user process context.
1394 */
1395#define sock_owned_by_user(sk)  ((sk)->sk_lock.owned)
1396
1397/*
1398 * Macro so as to not evaluate some arguments when
1399 * lockdep is not enabled.
1400 *
1401 * Mark both the sk_lock and the sk_lock.slock as a
1402 * per-address-family lock class.
1403 */
1404#define sock_lock_init_class_and_name(sk, sname, skey, name, key)       \
1405do {                                                                    \
1406        sk->sk_lock.owned = 0;                                          \
1407        init_waitqueue_head(&sk->sk_lock.wq);                           \
1408        spin_lock_init(&(sk)->sk_lock.slock);                           \
1409        debug_check_no_locks_freed((void *)&(sk)->sk_lock,              \
1410                        sizeof((sk)->sk_lock));                         \
1411        lockdep_set_class_and_name(&(sk)->sk_lock.slock,                \
1412                                (skey), (sname));                               \
1413        lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);     \
1414} while (0)
1415
1416extern void lock_sock_nested(struct sock *sk, int subclass);
1417
1418static inline void lock_sock(struct sock *sk)
1419{
1420        lock_sock_nested(sk, 0);
1421}
1422
1423extern void release_sock(struct sock *sk);
1424
1425/* BH context may only use the following locking interface. */
1426#define bh_lock_sock(__sk)      spin_lock(&((__sk)->sk_lock.slock))
1427#define bh_lock_sock_nested(__sk) \
1428                                spin_lock_nested(&((__sk)->sk_lock.slock), \
1429                                SINGLE_DEPTH_NESTING)
1430#define bh_unlock_sock(__sk)    spin_unlock(&((__sk)->sk_lock.slock))
1431
1432extern bool lock_sock_fast(struct sock *sk);
1433/**
1434 * unlock_sock_fast - complement of lock_sock_fast
1435 * @sk: socket
1436 * @slow: slow mode
1437 *
1438 * fast unlock socket for user context.
1439 * If slow mode is on, we call regular release_sock()
1440 */
1441static inline void unlock_sock_fast(struct sock *sk, bool slow)
1442{
1443        if (slow)
1444                release_sock(sk);
1445        else
1446                spin_unlock_bh(&sk->sk_lock.slock);
1447}
1448
1449
1450extern struct sock              *sk_alloc(struct net *net, int family,
1451                                          gfp_t priority,
1452                                          struct proto *prot);
1453extern void                     sk_free(struct sock *sk);
1454extern void                     sk_release_kernel(struct sock *sk);
1455extern struct sock              *sk_clone_lock(const struct sock *sk,
1456                                               const gfp_t priority);
1457
1458extern struct sk_buff           *sock_wmalloc(struct sock *sk,
1459                                              unsigned long size, int force,
1460                                              gfp_t priority);
1461extern struct sk_buff           *sock_rmalloc(struct sock *sk,
1462                                              unsigned long size, int force,
1463                                              gfp_t priority);
1464extern void                     sock_wfree(struct sk_buff *skb);
1465extern void                     sock_rfree(struct sk_buff *skb);
1466extern void                     sock_edemux(struct sk_buff *skb);
1467
1468extern int                      sock_setsockopt(struct socket *sock, int level,
1469                                                int op, char __user *optval,
1470                                                unsigned int optlen);
1471
1472extern int                      sock_getsockopt(struct socket *sock, int level,
1473                                                int op, char __user *optval,
1474                                                int __user *optlen);
1475extern struct sk_buff           *sock_alloc_send_skb(struct sock *sk,
1476                                                     unsigned long size,
1477                                                     int noblock,
1478                                                     int *errcode);
1479extern struct sk_buff           *sock_alloc_send_pskb(struct sock *sk,
1480                                                      unsigned long header_len,
1481                                                      unsigned long data_len,
1482                                                      int noblock,
1483                                                      int *errcode);
1484extern void *sock_kmalloc(struct sock *sk, int size,
1485                          gfp_t priority);
1486extern void sock_kfree_s(struct sock *sk, void *mem, int size);
1487extern void sk_send_sigurg(struct sock *sk);
1488
1489#ifdef CONFIG_CGROUPS
1490extern void sock_update_classid(struct sock *sk);
1491#else
1492static inline void sock_update_classid(struct sock *sk)
1493{
1494}
1495#endif
1496
1497/*
1498 * Functions to fill in entries in struct proto_ops when a protocol
1499 * does not implement a particular function.
1500 */
1501extern int                      sock_no_bind(struct socket *,
1502                                             struct sockaddr *, int);
1503extern int                      sock_no_connect(struct socket *,
1504                                                struct sockaddr *, int, int);
1505extern int                      sock_no_socketpair(struct socket *,
1506                                                   struct socket *);
1507extern int                      sock_no_accept(struct socket *,
1508                                               struct socket *, int);
1509extern int                      sock_no_getname(struct socket *,
1510                                                struct sockaddr *, int *, int);
1511extern unsigned int             sock_no_poll(struct file *, struct socket *,
1512                                             struct poll_table_struct *);
1513extern int                      sock_no_ioctl(struct socket *, unsigned int,
1514                                              unsigned long);
1515extern int                      sock_no_listen(struct socket *, int);
1516extern int                      sock_no_shutdown(struct socket *, int);
1517extern int                      sock_no_getsockopt(struct socket *, int , int,
1518                                                   char __user *, int __user *);
1519extern int                      sock_no_setsockopt(struct socket *, int, int,
1520                                                   char __user *, unsigned int);
1521extern int                      sock_no_sendmsg(struct kiocb *, struct socket *,
1522                                                struct msghdr *, size_t);
1523extern int                      sock_no_recvmsg(struct kiocb *, struct socket *,
1524                                                struct msghdr *, size_t, int);
1525extern int                      sock_no_mmap(struct file *file,
1526                                             struct socket *sock,
1527                                             struct vm_area_struct *vma);
1528extern ssize_t                  sock_no_sendpage(struct socket *sock,
1529                                                struct page *page,
1530                                                int offset, size_t size,
1531                                                int flags);
1532
1533/*
1534 * Functions to fill in entries in struct proto_ops when a protocol
1535 * uses the inet style.
1536 */
1537extern int sock_common_getsockopt(struct socket *sock, int level, int optname,
1538                                  char __user *optval, int __user *optlen);
1539extern int sock_common_recvmsg(struct kiocb *iocb, struct socket *sock,
1540                               struct msghdr *msg, size_t size, int flags);
1541extern int sock_common_setsockopt(struct socket *sock, int level, int optname,
1542                                  char __user *optval, unsigned int optlen);
1543extern int compat_sock_common_getsockopt(struct socket *sock, int level,
1544                int optname, char __user *optval, int __user *optlen);
1545extern int compat_sock_common_setsockopt(struct socket *sock, int level,
1546                int optname, char __user *optval, unsigned int optlen);
1547
1548extern void sk_common_release(struct sock *sk);
1549
1550/*
1551 *      Default socket callbacks and setup code
1552 */
1553
1554/* Initialise core socket variables */
1555extern void sock_init_data(struct socket *sock, struct sock *sk);
1556
1557extern void sk_filter_release_rcu(struct rcu_head *rcu);
1558
1559/**
1560 *      sk_filter_release - release a socket filter
1561 *      @fp: filter to remove
1562 *
1563 *      Remove a filter from a socket and release its resources.
1564 */
1565
1566static inline void sk_filter_release(struct sk_filter *fp)
1567{
1568        if (atomic_dec_and_test(&fp->refcnt))
1569                call_rcu(&fp->rcu, sk_filter_release_rcu);
1570}
1571
1572static inline void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
1573{
1574        unsigned int size = sk_filter_len(fp);
1575
1576        atomic_sub(size, &sk->sk_omem_alloc);
1577        sk_filter_release(fp);
1578}
1579
1580static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
1581{
1582        atomic_inc(&fp->refcnt);
1583        atomic_add(sk_filter_len(fp), &sk->sk_omem_alloc);
1584}
1585
1586/*
1587 * Socket reference counting postulates.
1588 *
1589 * * Each user of socket SHOULD hold a reference count.
1590 * * Each access point to socket (an hash table bucket, reference from a list,
1591 *   running timer, skb in flight MUST hold a reference count.
1592 * * When reference count hits 0, it means it will never increase back.
1593 * * When reference count hits 0, it means that no references from
1594 *   outside exist to this socket and current process on current CPU
1595 *   is last user and may/should destroy this socket.
1596 * * sk_free is called from any context: process, BH, IRQ. When
1597 *   it is called, socket has no references from outside -> sk_free
1598 *   may release descendant resources allocated by the socket, but
1599 *   to the time when it is called, socket is NOT referenced by any
1600 *   hash tables, lists etc.
1601 * * Packets, delivered from outside (from network or from another process)
1602 *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1603 *   when they sit in queue. Otherwise, packets will leak to hole, when
1604 *   socket is looked up by one cpu and unhasing is made by another CPU.
1605 *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1606 *   (leak to backlog). Packet socket does all the processing inside
1607 *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1608 *   use separate SMP lock, so that they are prone too.
1609 */
1610
1611/* Ungrab socket and destroy it, if it was the last reference. */
1612static inline void sock_put(struct sock *sk)
1613{
1614        if (atomic_dec_and_test(&sk->sk_refcnt))
1615                sk_free(sk);
1616}
1617
1618extern int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
1619                          const int nested);
1620
1621static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
1622{
1623        sk->sk_tx_queue_mapping = tx_queue;
1624}
1625
1626static inline void sk_tx_queue_clear(struct sock *sk)
1627{
1628        sk->sk_tx_queue_mapping = -1;
1629}
1630
1631static inline int sk_tx_queue_get(const struct sock *sk)
1632{
1633        return sk ? sk->sk_tx_queue_mapping : -1;
1634}
1635
1636static inline void sk_set_socket(struct sock *sk, struct socket *sock)
1637{
1638        sk_tx_queue_clear(sk);
1639        sk->sk_socket = sock;
1640}
1641
1642static inline wait_queue_head_t *sk_sleep(struct sock *sk)
1643{
1644        BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
1645        return &rcu_dereference_raw(sk->sk_wq)->wait;
1646}
1647/* Detach socket from process context.
1648 * Announce socket dead, detach it from wait queue and inode.
1649 * Note that parent inode held reference count on this struct sock,
1650 * we do not release it in this function, because protocol
1651 * probably wants some additional cleanups or even continuing
1652 * to work with this socket (TCP).
1653 */
1654static inline void sock_orphan(struct sock *sk)
1655{
1656        write_lock_bh(&sk->sk_callback_lock);
1657        sock_set_flag(sk, SOCK_DEAD);
1658        sk_set_socket(sk, NULL);
1659        sk->sk_wq  = NULL;
1660        write_unlock_bh(&sk->sk_callback_lock);
1661}
1662
1663static inline void sock_graft(struct sock *sk, struct socket *parent)
1664{
1665        write_lock_bh(&sk->sk_callback_lock);
1666        sk->sk_wq = parent->wq;
1667        parent->sk = sk;
1668        sk_set_socket(sk, parent);
1669        security_sock_graft(sk, parent);
1670        write_unlock_bh(&sk->sk_callback_lock);
1671}
1672
1673extern int sock_i_uid(struct sock *sk);
1674extern unsigned long sock_i_ino(struct sock *sk);
1675
1676static inline struct dst_entry *
1677__sk_dst_get(struct sock *sk)
1678{
1679        return rcu_dereference_check(sk->sk_dst_cache, sock_owned_by_user(sk) ||
1680                                                       lockdep_is_held(&sk->sk_lock.slock));
1681}
1682
1683static inline struct dst_entry *
1684sk_dst_get(struct sock *sk)
1685{
1686        struct dst_entry *dst;
1687
1688        rcu_read_lock();
1689        dst = rcu_dereference(sk->sk_dst_cache);
1690        if (dst)
1691                dst_hold(dst);
1692        rcu_read_unlock();
1693        return dst;
1694}
1695
1696extern void sk_reset_txq(struct sock *sk);
1697
1698static inline void dst_negative_advice(struct sock *sk)
1699{
1700        struct dst_entry *ndst, *dst = __sk_dst_get(sk);
1701
1702        if (dst && dst->ops->negative_advice) {
1703                ndst = dst->ops->negative_advice(dst);
1704
1705                if (ndst != dst) {
1706                        rcu_assign_pointer(sk->sk_dst_cache, ndst);
1707                        sk_reset_txq(sk);
1708                }
1709        }
1710}
1711
1712static inline void
1713__sk_dst_set(struct sock *sk, struct dst_entry *dst)
1714{
1715        struct dst_entry *old_dst;
1716
1717        sk_tx_queue_clear(sk);
1718        /*
1719         * This can be called while sk is owned by the caller only,
1720         * with no state that can be checked in a rcu_dereference_check() cond
1721         */
1722        old_dst = rcu_dereference_raw(sk->sk_dst_cache);
1723        rcu_assign_pointer(sk->sk_dst_cache, dst);
1724        dst_release(old_dst);
1725}
1726
1727static inline void
1728sk_dst_set(struct sock *sk, struct dst_entry *dst)
1729{
1730        spin_lock(&sk->sk_dst_lock);
1731        __sk_dst_set(sk, dst);
1732        spin_unlock(&sk->sk_dst_lock);
1733}
1734
1735static inline void
1736__sk_dst_reset(struct sock *sk)
1737{
1738        __sk_dst_set(sk, NULL);
1739}
1740
1741static inline void
1742sk_dst_reset(struct sock *sk)
1743{
1744        spin_lock(&sk->sk_dst_lock);
1745        __sk_dst_reset(sk);
1746        spin_unlock(&sk->sk_dst_lock);
1747}
1748
1749extern struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
1750
1751extern struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
1752
1753static inline bool sk_can_gso(const struct sock *sk)
1754{
1755        return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
1756}
1757
1758extern void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
1759
1760static inline void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
1761{
1762        sk->sk_route_nocaps |= flags;
1763        sk->sk_route_caps &= ~flags;
1764}
1765
1766static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
1767                                           char __user *from, char *to,
1768                                           int copy, int offset)
1769{
1770        if (skb->ip_summed == CHECKSUM_NONE) {
1771                int err = 0;
1772                __wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
1773                if (err)
1774                        return err;
1775                skb->csum = csum_block_add(skb->csum, csum, offset);
1776        } else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1777                if (!access_ok(VERIFY_READ, from, copy) ||
1778                    __copy_from_user_nocache(to, from, copy))
1779                        return -EFAULT;
1780        } else if (copy_from_user(to, from, copy))
1781                return -EFAULT;
1782
1783        return 0;
1784}
1785
1786static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
1787                                       char __user *from, int copy)
1788{
1789        int err, offset = skb->len;
1790
1791        err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
1792                                       copy, offset);
1793        if (err)
1794                __skb_trim(skb, offset);
1795
1796        return err;
1797}
1798
1799static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
1800                                           struct sk_buff *skb,
1801                                           struct page *page,
1802                                           int off, int copy)
1803{
1804        int err;
1805
1806        err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
1807                                       copy, skb->len);
1808        if (err)
1809                return err;
1810
1811        skb->len             += copy;
1812        skb->data_len        += copy;
1813        skb->truesize        += copy;
1814        sk->sk_wmem_queued   += copy;
1815        sk_mem_charge(sk, copy);
1816        return 0;
1817}
1818
1819static inline int skb_copy_to_page(struct sock *sk, char __user *from,
1820                                   struct sk_buff *skb, struct page *page,
1821                                   int off, int copy)
1822{
1823        if (skb->ip_summed == CHECKSUM_NONE) {
1824                int err = 0;
1825                __wsum csum = csum_and_copy_from_user(from,
1826                                                     page_address(page) + off,
1827                                                            copy, 0, &err);
1828                if (err)
1829                        return err;
1830                skb->csum = csum_block_add(skb->csum, csum, skb->len);
1831        } else if (copy_from_user(page_address(page) + off, from, copy))
1832                return -EFAULT;
1833
1834        skb->len             += copy;
1835        skb->data_len        += copy;
1836        skb->truesize        += copy;
1837        sk->sk_wmem_queued   += copy;
1838        sk_mem_charge(sk, copy);
1839        return 0;
1840}
1841
1842/**
1843 * sk_wmem_alloc_get - returns write allocations
1844 * @sk: socket
1845 *
1846 * Returns sk_wmem_alloc minus initial offset of one
1847 */
1848static inline int sk_wmem_alloc_get(const struct sock *sk)
1849{
1850        return atomic_read(&sk->sk_wmem_alloc) - 1;
1851}
1852
1853/**
1854 * sk_rmem_alloc_get - returns read allocations
1855 * @sk: socket
1856 *
1857 * Returns sk_rmem_alloc
1858 */
1859static inline int sk_rmem_alloc_get(const struct sock *sk)
1860{
1861        return atomic_read(&sk->sk_rmem_alloc);
1862}
1863
1864/**
1865 * sk_has_allocations - check if allocations are outstanding
1866 * @sk: socket
1867 *
1868 * Returns true if socket has write or read allocations
1869 */
1870static inline bool sk_has_allocations(const struct sock *sk)
1871{
1872        return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
1873}
1874
1875/**
1876 * wq_has_sleeper - check if there are any waiting processes
1877 * @wq: struct socket_wq
1878 *
1879 * Returns true if socket_wq has waiting processes
1880 *
1881 * The purpose of the wq_has_sleeper and sock_poll_wait is to wrap the memory
1882 * barrier call. They were added due to the race found within the tcp code.
1883 *
1884 * Consider following tcp code paths:
1885 *
1886 * CPU1                  CPU2
1887 *
1888 * sys_select            receive packet
1889 *   ...                 ...
1890 *   __add_wait_queue    update tp->rcv_nxt
1891 *   ...                 ...
1892 *   tp->rcv_nxt check   sock_def_readable
1893 *   ...                 {
1894 *   schedule               rcu_read_lock();
1895 *                          wq = rcu_dereference(sk->sk_wq);
1896 *                          if (wq && waitqueue_active(&wq->wait))
1897 *                              wake_up_interruptible(&wq->wait)
1898 *                          ...
1899 *                       }
1900 *
1901 * The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
1902 * in its cache, and so does the tp->rcv_nxt update on CPU2 side.  The CPU1
1903 * could then endup calling schedule and sleep forever if there are no more
1904 * data on the socket.
1905 *
1906 */
1907static inline bool wq_has_sleeper(struct socket_wq *wq)
1908{
1909        /* We need to be sure we are in sync with the
1910         * add_wait_queue modifications to the wait queue.
1911         *
1912         * This memory barrier is paired in the sock_poll_wait.
1913         */
1914        smp_mb();
1915        return wq && waitqueue_active(&wq->wait);
1916}
1917
1918/**
1919 * sock_poll_wait - place memory barrier behind the poll_wait call.
1920 * @filp:           file
1921 * @wait_address:   socket wait queue
1922 * @p:              poll_table
1923 *
1924 * See the comments in the wq_has_sleeper function.
1925 */
1926static inline void sock_poll_wait(struct file *filp,
1927                wait_queue_head_t *wait_address, poll_table *p)
1928{
1929        if (!poll_does_not_wait(p) && wait_address) {
1930                poll_wait(filp, wait_address, p);
1931                /* We need to be sure we are in sync with the
1932                 * socket flags modification.
1933                 *
1934                 * This memory barrier is paired in the wq_has_sleeper.
1935                 */
1936                smp_mb();
1937        }
1938}
1939
1940/*
1941 *      Queue a received datagram if it will fit. Stream and sequenced
1942 *      protocols can't normally use this as they need to fit buffers in
1943 *      and play with them.
1944 *
1945 *      Inlined as it's very short and called for pretty much every
1946 *      packet ever received.
1947 */
1948
1949static inline void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1950{
1951        skb_orphan(skb);
1952        skb->sk = sk;
1953        skb->destructor = sock_wfree;
1954        /*
1955         * We used to take a refcount on sk, but following operation
1956         * is enough to guarantee sk_free() wont free this sock until
1957         * all in-flight packets are completed
1958         */
1959        atomic_add(skb->truesize, &sk->sk_wmem_alloc);
1960}
1961
1962static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
1963{
1964        skb_orphan(skb);
1965        skb->sk = sk;
1966        skb->destructor = sock_rfree;
1967        atomic_add(skb->truesize, &sk->sk_rmem_alloc);
1968        sk_mem_charge(sk, skb->truesize);
1969}
1970
1971extern void sk_reset_timer(struct sock *sk, struct timer_list *timer,
1972                           unsigned long expires);
1973
1974extern void sk_stop_timer(struct sock *sk, struct timer_list *timer);
1975
1976extern int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
1977
1978extern int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
1979
1980/*
1981 *      Recover an error report and clear atomically
1982 */
1983
1984static inline int sock_error(struct sock *sk)
1985{
1986        int err;
1987        if (likely(!sk->sk_err))
1988                return 0;
1989        err = xchg(&sk->sk_err, 0);
1990        return -err;
1991}
1992
1993static inline unsigned long sock_wspace(struct sock *sk)
1994{
1995        int amt = 0;
1996
1997        if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
1998                amt = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
1999                if (amt < 0)
2000                        amt = 0;
2001        }
2002        return amt;
2003}
2004
2005static inline void sk_wake_async(struct sock *sk, int how, int band)
2006{
2007        if (sock_flag(sk, SOCK_FASYNC))
2008                sock_wake_async(sk->sk_socket, how, band);
2009}
2010
2011#define SOCK_MIN_SNDBUF 2048
2012/*
2013 * Since sk_rmem_alloc sums skb->truesize, even a small frame might need
2014 * sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak
2015 */
2016#define SOCK_MIN_RCVBUF (2048 + sizeof(struct sk_buff))
2017
2018static inline void sk_stream_moderate_sndbuf(struct sock *sk)
2019{
2020        if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
2021                sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
2022                sk->sk_sndbuf = max(sk->sk_sndbuf, SOCK_MIN_SNDBUF);
2023        }
2024}
2025
2026struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp);
2027
2028static inline struct page *sk_stream_alloc_page(struct sock *sk)
2029{
2030        struct page *page = NULL;
2031
2032        page = alloc_pages(sk->sk_allocation, 0);
2033        if (!page) {
2034                sk_enter_memory_pressure(sk);
2035                sk_stream_moderate_sndbuf(sk);
2036        }
2037        return page;
2038}
2039
2040/*
2041 *      Default write policy as shown to user space via poll/select/SIGIO
2042 */
2043static inline bool sock_writeable(const struct sock *sk)
2044{
2045        return atomic_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
2046}
2047
2048static inline gfp_t gfp_any(void)
2049{
2050        return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
2051}
2052
2053static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
2054{
2055        return noblock ? 0 : sk->sk_rcvtimeo;
2056}
2057
2058static inline long sock_sndtimeo(const struct sock *sk, bool noblock)
2059{
2060        return noblock ? 0 : sk->sk_sndtimeo;
2061}
2062
2063static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
2064{
2065        return (waitall ? len : min_t(int, sk->sk_rcvlowat, len)) ? : 1;
2066}
2067
2068/* Alas, with timeout socket operations are not restartable.
2069 * Compare this to poll().
2070 */
2071static inline int sock_intr_errno(long timeo)
2072{
2073        return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
2074}
2075
2076extern void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
2077        struct sk_buff *skb);
2078extern void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
2079        struct sk_buff *skb);
2080
2081static inline void
2082sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
2083{
2084        ktime_t kt = skb->tstamp;
2085        struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
2086
2087        /*
2088         * generate control messages if
2089         * - receive time stamping in software requested (SOCK_RCVTSTAMP
2090         *   or SOCK_TIMESTAMPING_RX_SOFTWARE)
2091         * - software time stamp available and wanted
2092         *   (SOCK_TIMESTAMPING_SOFTWARE)
2093         * - hardware time stamps available and wanted
2094         *   (SOCK_TIMESTAMPING_SYS_HARDWARE or
2095         *   SOCK_TIMESTAMPING_RAW_HARDWARE)
2096         */
2097        if (sock_flag(sk, SOCK_RCVTSTAMP) ||
2098            sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE) ||
2099            (kt.tv64 && sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE)) ||
2100            (hwtstamps->hwtstamp.tv64 &&
2101             sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE)) ||
2102            (hwtstamps->syststamp.tv64 &&
2103             sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE)))
2104                __sock_recv_timestamp(msg, sk, skb);
2105        else
2106                sk->sk_stamp = kt;
2107
2108        if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
2109                __sock_recv_wifi_status(msg, sk, skb);
2110}
2111
2112extern void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2113                                     struct sk_buff *skb);
2114
2115static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2116                                          struct sk_buff *skb)
2117{
2118#define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)                       | \
2119                           (1UL << SOCK_RCVTSTAMP)                      | \
2120                           (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE)       | \
2121                           (1UL << SOCK_TIMESTAMPING_SOFTWARE)          | \
2122                           (1UL << SOCK_TIMESTAMPING_RAW_HARDWARE)      | \
2123                           (1UL << SOCK_TIMESTAMPING_SYS_HARDWARE))
2124
2125        if (sk->sk_flags & FLAGS_TS_OR_DROPS)
2126                __sock_recv_ts_and_drops(msg, sk, skb);
2127        else
2128                sk->sk_stamp = skb->tstamp;
2129}
2130
2131/**
2132 * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
2133 * @sk:         socket sending this packet
2134 * @tx_flags:   filled with instructions for time stamping
2135 *
2136 * Currently only depends on SOCK_TIMESTAMPING* flags. Returns error code if
2137 * parameters are invalid.
2138 */
2139extern int sock_tx_timestamp(struct sock *sk, __u8 *tx_flags);
2140
2141/**
2142 * sk_eat_skb - Release a skb if it is no longer needed
2143 * @sk: socket to eat this skb from
2144 * @skb: socket buffer to eat
2145 * @copied_early: flag indicating whether DMA operations copied this data early
2146 *
2147 * This routine must be called with interrupts disabled or with the socket
2148 * locked so that the sk_buff queue operation is ok.
2149*/
2150#ifdef CONFIG_NET_DMA
2151static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, bool copied_early)
2152{
2153        __skb_unlink(skb, &sk->sk_receive_queue);
2154        if (!copied_early)
2155                __kfree_skb(skb);
2156        else
2157                __skb_queue_tail(&sk->sk_async_wait_queue, skb);
2158}
2159#else
2160static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, bool copied_early)
2161{
2162        __skb_unlink(skb, &sk->sk_receive_queue);
2163        __kfree_skb(skb);
2164}
2165#endif
2166
2167static inline
2168struct net *sock_net(const struct sock *sk)
2169{
2170        return read_pnet(&sk->sk_net);
2171}
2172
2173static inline
2174void sock_net_set(struct sock *sk, struct net *net)
2175{
2176        write_pnet(&sk->sk_net, net);
2177}
2178
2179/*
2180 * Kernel sockets, f.e. rtnl or icmp_socket, are a part of a namespace.
2181 * They should not hold a reference to a namespace in order to allow
2182 * to stop it.
2183 * Sockets after sk_change_net should be released using sk_release_kernel
2184 */
2185static inline void sk_change_net(struct sock *sk, struct net *net)
2186{
2187        put_net(sock_net(sk));
2188        sock_net_set(sk, hold_net(net));
2189}
2190
2191static inline struct sock *skb_steal_sock(struct sk_buff *skb)
2192{
2193        if (skb->sk) {
2194                struct sock *sk = skb->sk;
2195
2196                skb->destructor = NULL;
2197                skb->sk = NULL;
2198                return sk;
2199        }
2200        return NULL;
2201}
2202
2203extern void sock_enable_timestamp(struct sock *sk, int flag);
2204extern int sock_get_timestamp(struct sock *, struct timeval __user *);
2205extern int sock_get_timestampns(struct sock *, struct timespec __user *);
2206
2207/*
2208 *      Enable debug/info messages
2209 */
2210extern int net_msg_warn;
2211#define NETDEBUG(fmt, args...) \
2212        do { if (net_msg_warn) printk(fmt,##args); } while (0)
2213
2214#define LIMIT_NETDEBUG(fmt, args...) \
2215        do { if (net_msg_warn && net_ratelimit()) printk(fmt,##args); } while(0)
2216
2217extern __u32 sysctl_wmem_max;
2218extern __u32 sysctl_rmem_max;
2219
2220extern void sk_init(void);
2221
2222extern int sysctl_optmem_max;
2223
2224extern __u32 sysctl_wmem_default;
2225extern __u32 sysctl_rmem_default;
2226
2227#endif  /* _SOCK_H */
2228
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