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TOMOYO Linux Cross Reference
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/page_counter.h>
 58 #include <linux/memcontrol.h>
 59 #include <linux/static_key.h>
 60 #include <linux/sched.h>
 61 #include <linux/wait.h>
 62 #include <linux/cgroup-defs.h>
 63 
 64 #include <linux/filter.h>
 65 #include <linux/rculist_nulls.h>
 66 #include <linux/poll.h>
 67 
 68 #include <linux/atomic.h>
 69 #include <net/dst.h>
 70 #include <net/checksum.h>
 71 #include <net/tcp_states.h>
 72 #include <linux/net_tstamp.h>
 73 #include <net/smc.h>
 74 
 75 /*
 76  * This structure really needs to be cleaned up.
 77  * Most of it is for TCP, and not used by any of
 78  * the other protocols.
 79  */
 80 
 81 /* Define this to get the SOCK_DBG debugging facility. */
 82 #define SOCK_DEBUGGING
 83 #ifdef SOCK_DEBUGGING
 84 #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
 85                                         printk(KERN_DEBUG msg); } while (0)
 86 #else
 87 /* Validate arguments and do nothing */
 88 static inline __printf(2, 3)
 89 void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)
 90 {
 91 }
 92 #endif
 93 
 94 /* This is the per-socket lock.  The spinlock provides a synchronization
 95  * between user contexts and software interrupt processing, whereas the
 96  * mini-semaphore synchronizes multiple users amongst themselves.
 97  */
 98 typedef struct {
 99         spinlock_t              slock;
100         int                     owned;
101         wait_queue_head_t       wq;
102         /*
103          * We express the mutex-alike socket_lock semantics
104          * to the lock validator by explicitly managing
105          * the slock as a lock variant (in addition to
106          * the slock itself):
107          */
108 #ifdef CONFIG_DEBUG_LOCK_ALLOC
109         struct lockdep_map dep_map;
110 #endif
111 } socket_lock_t;
112 
113 struct sock;
114 struct proto;
115 struct net;
116 
117 typedef __u32 __bitwise __portpair;
118 typedef __u64 __bitwise __addrpair;
119 
120 /**
121  *      struct sock_common - minimal network layer representation of sockets
122  *      @skc_daddr: Foreign IPv4 addr
123  *      @skc_rcv_saddr: Bound local IPv4 addr
124  *      @skc_hash: hash value used with various protocol lookup tables
125  *      @skc_u16hashes: two u16 hash values used by UDP lookup tables
126  *      @skc_dport: placeholder for inet_dport/tw_dport
127  *      @skc_num: placeholder for inet_num/tw_num
128  *      @skc_family: network address family
129  *      @skc_state: Connection state
130  *      @skc_reuse: %SO_REUSEADDR setting
131  *      @skc_reuseport: %SO_REUSEPORT setting
132  *      @skc_bound_dev_if: bound device index if != 0
133  *      @skc_bind_node: bind hash linkage for various protocol lookup tables
134  *      @skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
135  *      @skc_prot: protocol handlers inside a network family
136  *      @skc_net: reference to the network namespace of this socket
137  *      @skc_node: main hash linkage for various protocol lookup tables
138  *      @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
139  *      @skc_tx_queue_mapping: tx queue number for this connection
140  *      @skc_flags: place holder for sk_flags
141  *              %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
142  *              %SO_OOBINLINE settings, %SO_TIMESTAMPING settings
143  *      @skc_incoming_cpu: record/match cpu processing incoming packets
144  *      @skc_refcnt: reference count
145  *
146  *      This is the minimal network layer representation of sockets, the header
147  *      for struct sock and struct inet_timewait_sock.
148  */
149 struct sock_common {
150         /* skc_daddr and skc_rcv_saddr must be grouped on a 8 bytes aligned
151          * address on 64bit arches : cf INET_MATCH()
152          */
153         union {
154                 __addrpair      skc_addrpair;
155                 struct {
156                         __be32  skc_daddr;
157                         __be32  skc_rcv_saddr;
158                 };
159         };
160         union  {
161                 unsigned int    skc_hash;
162                 __u16           skc_u16hashes[2];
163         };
164         /* skc_dport && skc_num must be grouped as well */
165         union {
166                 __portpair      skc_portpair;
167                 struct {
168                         __be16  skc_dport;
169                         __u16   skc_num;
170                 };
171         };
172 
173         unsigned short          skc_family;
174         volatile unsigned char  skc_state;
175         unsigned char           skc_reuse:4;
176         unsigned char           skc_reuseport:1;
177         unsigned char           skc_ipv6only:1;
178         unsigned char           skc_net_refcnt:1;
179         int                     skc_bound_dev_if;
180         union {
181                 struct hlist_node       skc_bind_node;
182                 struct hlist_node       skc_portaddr_node;
183         };
184         struct proto            *skc_prot;
185         possible_net_t          skc_net;
186 
187 #if IS_ENABLED(CONFIG_IPV6)
188         struct in6_addr         skc_v6_daddr;
189         struct in6_addr         skc_v6_rcv_saddr;
190 #endif
191 
192         atomic64_t              skc_cookie;
193 
194         /* following fields are padding to force
195          * offset(struct sock, sk_refcnt) == 128 on 64bit arches
196          * assuming IPV6 is enabled. We use this padding differently
197          * for different kind of 'sockets'
198          */
199         union {
200                 unsigned long   skc_flags;
201                 struct sock     *skc_listener; /* request_sock */
202                 struct inet_timewait_death_row *skc_tw_dr; /* inet_timewait_sock */
203         };
204         /*
205          * fields between dontcopy_begin/dontcopy_end
206          * are not copied in sock_copy()
207          */
208         /* private: */
209         int                     skc_dontcopy_begin[0];
210         /* public: */
211         union {
212                 struct hlist_node       skc_node;
213                 struct hlist_nulls_node skc_nulls_node;
214         };
215         int                     skc_tx_queue_mapping;
216         union {
217                 int             skc_incoming_cpu;
218                 u32             skc_rcv_wnd;
219                 u32             skc_tw_rcv_nxt; /* struct tcp_timewait_sock  */
220         };
221 
222         atomic_t                skc_refcnt;
223         /* private: */
224         int                     skc_dontcopy_end[0];
225         union {
226                 u32             skc_rxhash;
227                 u32             skc_window_clamp;
228                 u32             skc_tw_snd_nxt; /* struct tcp_timewait_sock */
229         };
230         /* public: */
231 };
232 
233 /**
234   *     struct sock - network layer representation of sockets
235   *     @__sk_common: shared layout with inet_timewait_sock
236   *     @sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
237   *     @sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
238   *     @sk_lock:       synchronizer
239   *     @sk_kern_sock: True if sock is using kernel lock classes
240   *     @sk_rcvbuf: size of receive buffer in bytes
241   *     @sk_wq: sock wait queue and async head
242   *     @sk_rx_dst: receive input route used by early demux
243   *     @sk_dst_cache: destination cache
244   *     @sk_dst_pending_confirm: need to confirm neighbour
245   *     @sk_policy: flow policy
246   *     @sk_receive_queue: incoming packets
247   *     @sk_wmem_alloc: transmit queue bytes committed
248   *     @sk_write_queue: Packet sending queue
249   *     @sk_omem_alloc: "o" is "option" or "other"
250   *     @sk_wmem_queued: persistent queue size
251   *     @sk_forward_alloc: space allocated forward
252   *     @sk_napi_id: id of the last napi context to receive data for sk
253   *     @sk_ll_usec: usecs to busypoll when there is no data
254   *     @sk_allocation: allocation mode
255   *     @sk_pacing_rate: Pacing rate (if supported by transport/packet scheduler)
256   *     @sk_max_pacing_rate: Maximum pacing rate (%SO_MAX_PACING_RATE)
257   *     @sk_sndbuf: size of send buffer in bytes
258   *     @sk_padding: unused element for alignment
259   *     @sk_no_check_tx: %SO_NO_CHECK setting, set checksum in TX packets
260   *     @sk_no_check_rx: allow zero checksum in RX packets
261   *     @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
262   *     @sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)
263   *     @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
264   *     @sk_gso_max_size: Maximum GSO segment size to build
265   *     @sk_gso_max_segs: Maximum number of GSO segments
266   *     @sk_lingertime: %SO_LINGER l_linger setting
267   *     @sk_backlog: always used with the per-socket spinlock held
268   *     @sk_callback_lock: used with the callbacks in the end of this struct
269   *     @sk_error_queue: rarely used
270   *     @sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
271   *                       IPV6_ADDRFORM for instance)
272   *     @sk_err: last error
273   *     @sk_err_soft: errors that don't cause failure but are the cause of a
274   *                   persistent failure not just 'timed out'
275   *     @sk_drops: raw/udp drops counter
276   *     @sk_ack_backlog: current listen backlog
277   *     @sk_max_ack_backlog: listen backlog set in listen()
278   *     @sk_priority: %SO_PRIORITY setting
279   *     @sk_type: socket type (%SOCK_STREAM, etc)
280   *     @sk_protocol: which protocol this socket belongs in this network family
281   *     @sk_peer_pid: &struct pid for this socket's peer
282   *     @sk_peer_cred: %SO_PEERCRED setting
283   *     @sk_rcvlowat: %SO_RCVLOWAT setting
284   *     @sk_rcvtimeo: %SO_RCVTIMEO setting
285   *     @sk_sndtimeo: %SO_SNDTIMEO setting
286   *     @sk_txhash: computed flow hash for use on transmit
287   *     @sk_filter: socket filtering instructions
288   *     @sk_timer: sock cleanup timer
289   *     @sk_stamp: time stamp of last packet received
290   *     @sk_tsflags: SO_TIMESTAMPING socket options
291   *     @sk_tskey: counter to disambiguate concurrent tstamp requests
292   *     @sk_socket: Identd and reporting IO signals
293   *     @sk_user_data: RPC layer private data
294   *     @sk_frag: cached page frag
295   *     @sk_peek_off: current peek_offset value
296   *     @sk_send_head: front of stuff to transmit
297   *     @sk_security: used by security modules
298   *     @sk_mark: generic packet mark
299   *     @sk_cgrp_data: cgroup data for this cgroup
300   *     @sk_memcg: this socket's memory cgroup association
301   *     @sk_write_pending: a write to stream socket waits to start
302   *     @sk_state_change: callback to indicate change in the state of the sock
303   *     @sk_data_ready: callback to indicate there is data to be processed
304   *     @sk_write_space: callback to indicate there is bf sending space available
305   *     @sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
306   *     @sk_backlog_rcv: callback to process the backlog
307   *     @sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
308   *     @sk_reuseport_cb: reuseport group container
309   *     @sk_rcu: used during RCU grace period
310   */
311 struct sock {
312         /*
313          * Now struct inet_timewait_sock also uses sock_common, so please just
314          * don't add nothing before this first member (__sk_common) --acme
315          */
316         struct sock_common      __sk_common;
317 #define sk_node                 __sk_common.skc_node
318 #define sk_nulls_node           __sk_common.skc_nulls_node
319 #define sk_refcnt               __sk_common.skc_refcnt
320 #define sk_tx_queue_mapping     __sk_common.skc_tx_queue_mapping
321 
322 #define sk_dontcopy_begin       __sk_common.skc_dontcopy_begin
323 #define sk_dontcopy_end         __sk_common.skc_dontcopy_end
324 #define sk_hash                 __sk_common.skc_hash
325 #define sk_portpair             __sk_common.skc_portpair
326 #define sk_num                  __sk_common.skc_num
327 #define sk_dport                __sk_common.skc_dport
328 #define sk_addrpair             __sk_common.skc_addrpair
329 #define sk_daddr                __sk_common.skc_daddr
330 #define sk_rcv_saddr            __sk_common.skc_rcv_saddr
331 #define sk_family               __sk_common.skc_family
332 #define sk_state                __sk_common.skc_state
333 #define sk_reuse                __sk_common.skc_reuse
334 #define sk_reuseport            __sk_common.skc_reuseport
335 #define sk_ipv6only             __sk_common.skc_ipv6only
336 #define sk_net_refcnt           __sk_common.skc_net_refcnt
337 #define sk_bound_dev_if         __sk_common.skc_bound_dev_if
338 #define sk_bind_node            __sk_common.skc_bind_node
339 #define sk_prot                 __sk_common.skc_prot
340 #define sk_net                  __sk_common.skc_net
341 #define sk_v6_daddr             __sk_common.skc_v6_daddr
342 #define sk_v6_rcv_saddr __sk_common.skc_v6_rcv_saddr
343 #define sk_cookie               __sk_common.skc_cookie
344 #define sk_incoming_cpu         __sk_common.skc_incoming_cpu
345 #define sk_flags                __sk_common.skc_flags
346 #define sk_rxhash               __sk_common.skc_rxhash
347 
348         socket_lock_t           sk_lock;
349         atomic_t                sk_drops;
350         int                     sk_rcvlowat;
351         struct sk_buff_head     sk_error_queue;
352         struct sk_buff_head     sk_receive_queue;
353         /*
354          * The backlog queue is special, it is always used with
355          * the per-socket spinlock held and requires low latency
356          * access. Therefore we special case it's implementation.
357          * Note : rmem_alloc is in this structure to fill a hole
358          * on 64bit arches, not because its logically part of
359          * backlog.
360          */
361         struct {
362                 atomic_t        rmem_alloc;
363                 int             len;
364                 struct sk_buff  *head;
365                 struct sk_buff  *tail;
366         } sk_backlog;
367 #define sk_rmem_alloc sk_backlog.rmem_alloc
368 
369         int                     sk_forward_alloc;
370 #ifdef CONFIG_NET_RX_BUSY_POLL
371         unsigned int            sk_ll_usec;
372         /* ===== mostly read cache line ===== */
373         unsigned int            sk_napi_id;
374 #endif
375         int                     sk_rcvbuf;
376 
377         struct sk_filter __rcu  *sk_filter;
378         union {
379                 struct socket_wq __rcu  *sk_wq;
380                 struct socket_wq        *sk_wq_raw;
381         };
382 #ifdef CONFIG_XFRM
383         struct xfrm_policy __rcu *sk_policy[2];
384 #endif
385         struct dst_entry        *sk_rx_dst;
386         struct dst_entry __rcu  *sk_dst_cache;
387         atomic_t                sk_omem_alloc;
388         int                     sk_sndbuf;
389 
390         /* ===== cache line for TX ===== */
391         int                     sk_wmem_queued;
392         atomic_t                sk_wmem_alloc;
393         unsigned long           sk_tsq_flags;
394         struct sk_buff          *sk_send_head;
395         struct sk_buff_head     sk_write_queue;
396         __s32                   sk_peek_off;
397         int                     sk_write_pending;
398         __u32                   sk_dst_pending_confirm;
399         /* Note: 32bit hole on 64bit arches */
400         long                    sk_sndtimeo;
401         struct timer_list       sk_timer;
402         __u32                   sk_priority;
403         __u32                   sk_mark;
404         u32                     sk_pacing_rate; /* bytes per second */
405         u32                     sk_max_pacing_rate;
406         struct page_frag        sk_frag;
407         netdev_features_t       sk_route_caps;
408         netdev_features_t       sk_route_nocaps;
409         int                     sk_gso_type;
410         unsigned int            sk_gso_max_size;
411         gfp_t                   sk_allocation;
412         __u32                   sk_txhash;
413 
414         /*
415          * Because of non atomicity rules, all
416          * changes are protected by socket lock.
417          */
418         unsigned int            __sk_flags_offset[0];
419 #ifdef __BIG_ENDIAN_BITFIELD
420 #define SK_FL_PROTO_SHIFT  16
421 #define SK_FL_PROTO_MASK   0x00ff0000
422 
423 #define SK_FL_TYPE_SHIFT   0
424 #define SK_FL_TYPE_MASK    0x0000ffff
425 #else
426 #define SK_FL_PROTO_SHIFT  8
427 #define SK_FL_PROTO_MASK   0x0000ff00
428 
429 #define SK_FL_TYPE_SHIFT   16
430 #define SK_FL_TYPE_MASK    0xffff0000
431 #endif
432 
433         kmemcheck_bitfield_begin(flags);
434         unsigned int            sk_padding : 1,
435                                 sk_kern_sock : 1,
436                                 sk_no_check_tx : 1,
437                                 sk_no_check_rx : 1,
438                                 sk_userlocks : 4,
439                                 sk_protocol  : 8,
440                                 sk_type      : 16;
441 #define SK_PROTOCOL_MAX U8_MAX
442         kmemcheck_bitfield_end(flags);
443 
444         u16                     sk_gso_max_segs;
445         unsigned long           sk_lingertime;
446         struct proto            *sk_prot_creator;
447         rwlock_t                sk_callback_lock;
448         int                     sk_err,
449                                 sk_err_soft;
450         u32                     sk_ack_backlog;
451         u32                     sk_max_ack_backlog;
452         kuid_t                  sk_uid;
453         struct pid              *sk_peer_pid;
454         const struct cred       *sk_peer_cred;
455         long                    sk_rcvtimeo;
456         ktime_t                 sk_stamp;
457         u16                     sk_tsflags;
458         u8                      sk_shutdown;
459         u32                     sk_tskey;
460         struct socket           *sk_socket;
461         void                    *sk_user_data;
462 #ifdef CONFIG_SECURITY
463         void                    *sk_security;
464 #endif
465         struct sock_cgroup_data sk_cgrp_data;
466         struct mem_cgroup       *sk_memcg;
467         void                    (*sk_state_change)(struct sock *sk);
468         void                    (*sk_data_ready)(struct sock *sk);
469         void                    (*sk_write_space)(struct sock *sk);
470         void                    (*sk_error_report)(struct sock *sk);
471         int                     (*sk_backlog_rcv)(struct sock *sk,
472                                                   struct sk_buff *skb);
473         void                    (*sk_destruct)(struct sock *sk);
474         struct sock_reuseport __rcu     *sk_reuseport_cb;
475         struct rcu_head         sk_rcu;
476 };
477 
478 #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data)))
479 
480 #define rcu_dereference_sk_user_data(sk)        rcu_dereference(__sk_user_data((sk)))
481 #define rcu_assign_sk_user_data(sk, ptr)        rcu_assign_pointer(__sk_user_data((sk)), ptr)
482 
483 /*
484  * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
485  * or not whether his port will be reused by someone else. SK_FORCE_REUSE
486  * on a socket means that the socket will reuse everybody else's port
487  * without looking at the other's sk_reuse value.
488  */
489 
490 #define SK_NO_REUSE     0
491 #define SK_CAN_REUSE    1
492 #define SK_FORCE_REUSE  2
493 
494 int sk_set_peek_off(struct sock *sk, int val);
495 
496 static inline int sk_peek_offset(struct sock *sk, int flags)
497 {
498         if (unlikely(flags & MSG_PEEK)) {
499                 s32 off = READ_ONCE(sk->sk_peek_off);
500                 if (off >= 0)
501                         return off;
502         }
503 
504         return 0;
505 }
506 
507 static inline void sk_peek_offset_bwd(struct sock *sk, int val)
508 {
509         s32 off = READ_ONCE(sk->sk_peek_off);
510 
511         if (unlikely(off >= 0)) {
512                 off = max_t(s32, off - val, 0);
513                 WRITE_ONCE(sk->sk_peek_off, off);
514         }
515 }
516 
517 static inline void sk_peek_offset_fwd(struct sock *sk, int val)
518 {
519         sk_peek_offset_bwd(sk, -val);
520 }
521 
522 /*
523  * Hashed lists helper routines
524  */
525 static inline struct sock *sk_entry(const struct hlist_node *node)
526 {
527         return hlist_entry(node, struct sock, sk_node);
528 }
529 
530 static inline struct sock *__sk_head(const struct hlist_head *head)
531 {
532         return hlist_entry(head->first, struct sock, sk_node);
533 }
534 
535 static inline struct sock *sk_head(const struct hlist_head *head)
536 {
537         return hlist_empty(head) ? NULL : __sk_head(head);
538 }
539 
540 static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
541 {
542         return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
543 }
544 
545 static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
546 {
547         return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
548 }
549 
550 static inline struct sock *sk_next(const struct sock *sk)
551 {
552         return hlist_entry_safe(sk->sk_node.next, struct sock, sk_node);
553 }
554 
555 static inline struct sock *sk_nulls_next(const struct sock *sk)
556 {
557         return (!is_a_nulls(sk->sk_nulls_node.next)) ?
558                 hlist_nulls_entry(sk->sk_nulls_node.next,
559                                   struct sock, sk_nulls_node) :
560                 NULL;
561 }
562 
563 static inline bool sk_unhashed(const struct sock *sk)
564 {
565         return hlist_unhashed(&sk->sk_node);
566 }
567 
568 static inline bool sk_hashed(const struct sock *sk)
569 {
570         return !sk_unhashed(sk);
571 }
572 
573 static inline void sk_node_init(struct hlist_node *node)
574 {
575         node->pprev = NULL;
576 }
577 
578 static inline void sk_nulls_node_init(struct hlist_nulls_node *node)
579 {
580         node->pprev = NULL;
581 }
582 
583 static inline void __sk_del_node(struct sock *sk)
584 {
585         __hlist_del(&sk->sk_node);
586 }
587 
588 /* NB: equivalent to hlist_del_init_rcu */
589 static inline bool __sk_del_node_init(struct sock *sk)
590 {
591         if (sk_hashed(sk)) {
592                 __sk_del_node(sk);
593                 sk_node_init(&sk->sk_node);
594                 return true;
595         }
596         return false;
597 }
598 
599 /* Grab socket reference count. This operation is valid only
600    when sk is ALREADY grabbed f.e. it is found in hash table
601    or a list and the lookup is made under lock preventing hash table
602    modifications.
603  */
604 
605 static __always_inline void sock_hold(struct sock *sk)
606 {
607         atomic_inc(&sk->sk_refcnt);
608 }
609 
610 /* Ungrab socket in the context, which assumes that socket refcnt
611    cannot hit zero, f.e. it is true in context of any socketcall.
612  */
613 static __always_inline void __sock_put(struct sock *sk)
614 {
615         atomic_dec(&sk->sk_refcnt);
616 }
617 
618 static inline bool sk_del_node_init(struct sock *sk)
619 {
620         bool rc = __sk_del_node_init(sk);
621 
622         if (rc) {
623                 /* paranoid for a while -acme */
624                 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
625                 __sock_put(sk);
626         }
627         return rc;
628 }
629 #define sk_del_node_init_rcu(sk)        sk_del_node_init(sk)
630 
631 static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)
632 {
633         if (sk_hashed(sk)) {
634                 hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
635                 return true;
636         }
637         return false;
638 }
639 
640 static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
641 {
642         bool rc = __sk_nulls_del_node_init_rcu(sk);
643 
644         if (rc) {
645                 /* paranoid for a while -acme */
646                 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
647                 __sock_put(sk);
648         }
649         return rc;
650 }
651 
652 static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)
653 {
654         hlist_add_head(&sk->sk_node, list);
655 }
656 
657 static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
658 {
659         sock_hold(sk);
660         __sk_add_node(sk, list);
661 }
662 
663 static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
664 {
665         sock_hold(sk);
666         if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
667             sk->sk_family == AF_INET6)
668                 hlist_add_tail_rcu(&sk->sk_node, list);
669         else
670                 hlist_add_head_rcu(&sk->sk_node, list);
671 }
672 
673 static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
674 {
675         if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
676             sk->sk_family == AF_INET6)
677                 hlist_nulls_add_tail_rcu(&sk->sk_nulls_node, list);
678         else
679                 hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
680 }
681 
682 static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
683 {
684         sock_hold(sk);
685         __sk_nulls_add_node_rcu(sk, list);
686 }
687 
688 static inline void __sk_del_bind_node(struct sock *sk)
689 {
690         __hlist_del(&sk->sk_bind_node);
691 }
692 
693 static inline void sk_add_bind_node(struct sock *sk,
694                                         struct hlist_head *list)
695 {
696         hlist_add_head(&sk->sk_bind_node, list);
697 }
698 
699 #define sk_for_each(__sk, list) \
700         hlist_for_each_entry(__sk, list, sk_node)
701 #define sk_for_each_rcu(__sk, list) \
702         hlist_for_each_entry_rcu(__sk, list, sk_node)
703 #define sk_nulls_for_each(__sk, node, list) \
704         hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
705 #define sk_nulls_for_each_rcu(__sk, node, list) \
706         hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
707 #define sk_for_each_from(__sk) \
708         hlist_for_each_entry_from(__sk, sk_node)
709 #define sk_nulls_for_each_from(__sk, node) \
710         if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
711                 hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
712 #define sk_for_each_safe(__sk, tmp, list) \
713         hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
714 #define sk_for_each_bound(__sk, list) \
715         hlist_for_each_entry(__sk, list, sk_bind_node)
716 
717 /**
718  * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset
719  * @tpos:       the type * to use as a loop cursor.
720  * @pos:        the &struct hlist_node to use as a loop cursor.
721  * @head:       the head for your list.
722  * @offset:     offset of hlist_node within the struct.
723  *
724  */
725 #define sk_for_each_entry_offset_rcu(tpos, pos, head, offset)                  \
726         for (pos = rcu_dereference((head)->first);                             \
727              pos != NULL &&                                                    \
728                 ({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;});       \
729              pos = rcu_dereference(pos->next))
730 
731 static inline struct user_namespace *sk_user_ns(struct sock *sk)
732 {
733         /* Careful only use this in a context where these parameters
734          * can not change and must all be valid, such as recvmsg from
735          * userspace.
736          */
737         return sk->sk_socket->file->f_cred->user_ns;
738 }
739 
740 /* Sock flags */
741 enum sock_flags {
742         SOCK_DEAD,
743         SOCK_DONE,
744         SOCK_URGINLINE,
745         SOCK_KEEPOPEN,
746         SOCK_LINGER,
747         SOCK_DESTROY,
748         SOCK_BROADCAST,
749         SOCK_TIMESTAMP,
750         SOCK_ZAPPED,
751         SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
752         SOCK_DBG, /* %SO_DEBUG setting */
753         SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
754         SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
755         SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
756         SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
757         SOCK_MEMALLOC, /* VM depends on this socket for swapping */
758         SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
759         SOCK_FASYNC, /* fasync() active */
760         SOCK_RXQ_OVFL,
761         SOCK_ZEROCOPY, /* buffers from userspace */
762         SOCK_WIFI_STATUS, /* push wifi status to userspace */
763         SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
764                      * Will use last 4 bytes of packet sent from
765                      * user-space instead.
766                      */
767         SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
768         SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
769         SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */
770 };
771 
772 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
773 
774 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
775 {
776         nsk->sk_flags = osk->sk_flags;
777 }
778 
779 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
780 {
781         __set_bit(flag, &sk->sk_flags);
782 }
783 
784 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
785 {
786         __clear_bit(flag, &sk->sk_flags);
787 }
788 
789 static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
790 {
791         return test_bit(flag, &sk->sk_flags);
792 }
793 
794 #ifdef CONFIG_NET
795 extern struct static_key memalloc_socks;
796 static inline int sk_memalloc_socks(void)
797 {
798         return static_key_false(&memalloc_socks);
799 }
800 #else
801 
802 static inline int sk_memalloc_socks(void)
803 {
804         return 0;
805 }
806 
807 #endif
808 
809 static inline gfp_t sk_gfp_mask(const struct sock *sk, gfp_t gfp_mask)
810 {
811         return gfp_mask | (sk->sk_allocation & __GFP_MEMALLOC);
812 }
813 
814 static inline void sk_acceptq_removed(struct sock *sk)
815 {
816         sk->sk_ack_backlog--;
817 }
818 
819 static inline void sk_acceptq_added(struct sock *sk)
820 {
821         sk->sk_ack_backlog++;
822 }
823 
824 static inline bool sk_acceptq_is_full(const struct sock *sk)
825 {
826         return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
827 }
828 
829 /*
830  * Compute minimal free write space needed to queue new packets.
831  */
832 static inline int sk_stream_min_wspace(const struct sock *sk)
833 {
834         return sk->sk_wmem_queued >> 1;
835 }
836 
837 static inline int sk_stream_wspace(const struct sock *sk)
838 {
839         return sk->sk_sndbuf - sk->sk_wmem_queued;
840 }
841 
842 void sk_stream_write_space(struct sock *sk);
843 
844 /* OOB backlog add */
845 static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
846 {
847         /* dont let skb dst not refcounted, we are going to leave rcu lock */
848         skb_dst_force_safe(skb);
849 
850         if (!sk->sk_backlog.tail)
851                 sk->sk_backlog.head = skb;
852         else
853                 sk->sk_backlog.tail->next = skb;
854 
855         sk->sk_backlog.tail = skb;
856         skb->next = NULL;
857 }
858 
859 /*
860  * Take into account size of receive queue and backlog queue
861  * Do not take into account this skb truesize,
862  * to allow even a single big packet to come.
863  */
864 static inline bool sk_rcvqueues_full(const struct sock *sk, unsigned int limit)
865 {
866         unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
867 
868         return qsize > limit;
869 }
870 
871 /* The per-socket spinlock must be held here. */
872 static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
873                                               unsigned int limit)
874 {
875         if (sk_rcvqueues_full(sk, limit))
876                 return -ENOBUFS;
877 
878         /*
879          * If the skb was allocated from pfmemalloc reserves, only
880          * allow SOCK_MEMALLOC sockets to use it as this socket is
881          * helping free memory
882          */
883         if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
884                 return -ENOMEM;
885 
886         __sk_add_backlog(sk, skb);
887         sk->sk_backlog.len += skb->truesize;
888         return 0;
889 }
890 
891 int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
892 
893 static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
894 {
895         if (sk_memalloc_socks() && skb_pfmemalloc(skb))
896                 return __sk_backlog_rcv(sk, skb);
897 
898         return sk->sk_backlog_rcv(sk, skb);
899 }
900 
901 static inline void sk_incoming_cpu_update(struct sock *sk)
902 {
903         sk->sk_incoming_cpu = raw_smp_processor_id();
904 }
905 
906 static inline void sock_rps_record_flow_hash(__u32 hash)
907 {
908 #ifdef CONFIG_RPS
909         struct rps_sock_flow_table *sock_flow_table;
910 
911         rcu_read_lock();
912         sock_flow_table = rcu_dereference(rps_sock_flow_table);
913         rps_record_sock_flow(sock_flow_table, hash);
914         rcu_read_unlock();
915 #endif
916 }
917 
918 static inline void sock_rps_record_flow(const struct sock *sk)
919 {
920 #ifdef CONFIG_RPS
921         if (static_key_false(&rfs_needed)) {
922                 /* Reading sk->sk_rxhash might incur an expensive cache line
923                  * miss.
924                  *
925                  * TCP_ESTABLISHED does cover almost all states where RFS
926                  * might be useful, and is cheaper [1] than testing :
927                  *      IPv4: inet_sk(sk)->inet_daddr
928                  *      IPv6: ipv6_addr_any(&sk->sk_v6_daddr)
929                  * OR   an additional socket flag
930                  * [1] : sk_state and sk_prot are in the same cache line.
931                  */
932                 if (sk->sk_state == TCP_ESTABLISHED)
933                         sock_rps_record_flow_hash(sk->sk_rxhash);
934         }
935 #endif
936 }
937 
938 static inline void sock_rps_save_rxhash(struct sock *sk,
939                                         const struct sk_buff *skb)
940 {
941 #ifdef CONFIG_RPS
942         if (unlikely(sk->sk_rxhash != skb->hash))
943                 sk->sk_rxhash = skb->hash;
944 #endif
945 }
946 
947 static inline void sock_rps_reset_rxhash(struct sock *sk)
948 {
949 #ifdef CONFIG_RPS
950         sk->sk_rxhash = 0;
951 #endif
952 }
953 
954 #define sk_wait_event(__sk, __timeo, __condition, __wait)               \
955         ({      int __rc;                                               \
956                 release_sock(__sk);                                     \
957                 __rc = __condition;                                     \
958                 if (!__rc) {                                            \
959                         *(__timeo) = wait_woken(__wait,                 \
960                                                 TASK_INTERRUPTIBLE,     \
961                                                 *(__timeo));            \
962                 }                                                       \
963                 sched_annotate_sleep();                                 \
964                 lock_sock(__sk);                                        \
965                 __rc = __condition;                                     \
966                 __rc;                                                   \
967         })
968 
969 int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
970 int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
971 void sk_stream_wait_close(struct sock *sk, long timeo_p);
972 int sk_stream_error(struct sock *sk, int flags, int err);
973 void sk_stream_kill_queues(struct sock *sk);
974 void sk_set_memalloc(struct sock *sk);
975 void sk_clear_memalloc(struct sock *sk);
976 
977 void __sk_flush_backlog(struct sock *sk);
978 
979 static inline bool sk_flush_backlog(struct sock *sk)
980 {
981         if (unlikely(READ_ONCE(sk->sk_backlog.tail))) {
982                 __sk_flush_backlog(sk);
983                 return true;
984         }
985         return false;
986 }
987 
988 int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb);
989 
990 struct request_sock_ops;
991 struct timewait_sock_ops;
992 struct inet_hashinfo;
993 struct raw_hashinfo;
994 struct smc_hashinfo;
995 struct module;
996 
997 /*
998  * caches using SLAB_TYPESAFE_BY_RCU should let .next pointer from nulls nodes
999  * un-modified. Special care is taken when initializing object to zero.
1000  */
1001 static inline void sk_prot_clear_nulls(struct sock *sk, int size)
1002 {
1003         if (offsetof(struct sock, sk_node.next) != 0)
1004                 memset(sk, 0, offsetof(struct sock, sk_node.next));
1005         memset(&sk->sk_node.pprev, 0,
1006                size - offsetof(struct sock, sk_node.pprev));
1007 }
1008 
1009 /* Networking protocol blocks we attach to sockets.
1010  * socket layer -> transport layer interface
1011  */
1012 struct proto {
1013         void                    (*close)(struct sock *sk,
1014                                         long timeout);
1015         int                     (*connect)(struct sock *sk,
1016                                         struct sockaddr *uaddr,
1017                                         int addr_len);
1018         int                     (*disconnect)(struct sock *sk, int flags);
1019 
1020         struct sock *           (*accept)(struct sock *sk, int flags, int *err,
1021                                           bool kern);
1022 
1023         int                     (*ioctl)(struct sock *sk, int cmd,
1024                                          unsigned long arg);
1025         int                     (*init)(struct sock *sk);
1026         void                    (*destroy)(struct sock *sk);
1027         void                    (*shutdown)(struct sock *sk, int how);
1028         int                     (*setsockopt)(struct sock *sk, int level,
1029                                         int optname, char __user *optval,
1030                                         unsigned int optlen);
1031         int                     (*getsockopt)(struct sock *sk, int level,
1032                                         int optname, char __user *optval,
1033                                         int __user *option);
1034         void                    (*keepalive)(struct sock *sk, int valbool);
1035 #ifdef CONFIG_COMPAT
1036         int                     (*compat_setsockopt)(struct sock *sk,
1037                                         int level,
1038                                         int optname, char __user *optval,
1039                                         unsigned int optlen);
1040         int                     (*compat_getsockopt)(struct sock *sk,
1041                                         int level,
1042                                         int optname, char __user *optval,
1043                                         int __user *option);
1044         int                     (*compat_ioctl)(struct sock *sk,
1045                                         unsigned int cmd, unsigned long arg);
1046 #endif
1047         int                     (*sendmsg)(struct sock *sk, struct msghdr *msg,
1048                                            size_t len);
1049         int                     (*recvmsg)(struct sock *sk, struct msghdr *msg,
1050                                            size_t len, int noblock, int flags,
1051                                            int *addr_len);
1052         int                     (*sendpage)(struct sock *sk, struct page *page,
1053                                         int offset, size_t size, int flags);
1054         int                     (*bind)(struct sock *sk,
1055                                         struct sockaddr *uaddr, int addr_len);
1056 
1057         int                     (*backlog_rcv) (struct sock *sk,
1058                                                 struct sk_buff *skb);
1059 
1060         void            (*release_cb)(struct sock *sk);
1061 
1062         /* Keeping track of sk's, looking them up, and port selection methods. */
1063         int                     (*hash)(struct sock *sk);
1064         void                    (*unhash)(struct sock *sk);
1065         void                    (*rehash)(struct sock *sk);
1066         int                     (*get_port)(struct sock *sk, unsigned short snum);
1067 
1068         /* Keeping track of sockets in use */
1069 #ifdef CONFIG_PROC_FS
1070         unsigned int            inuse_idx;
1071 #endif
1072 
1073         bool                    (*stream_memory_free)(const struct sock *sk);
1074         /* Memory pressure */
1075         void                    (*enter_memory_pressure)(struct sock *sk);
1076         atomic_long_t           *memory_allocated;      /* Current allocated memory. */
1077         struct percpu_counter   *sockets_allocated;     /* Current number of sockets. */
1078         /*
1079          * Pressure flag: try to collapse.
1080          * Technical note: it is used by multiple contexts non atomically.
1081          * All the __sk_mem_schedule() is of this nature: accounting
1082          * is strict, actions are advisory and have some latency.
1083          */
1084         int                     *memory_pressure;
1085         long                    *sysctl_mem;
1086         int                     *sysctl_wmem;
1087         int                     *sysctl_rmem;
1088         int                     max_header;
1089         bool                    no_autobind;
1090 
1091         struct kmem_cache       *slab;
1092         unsigned int            obj_size;
1093         int                     slab_flags;
1094 
1095         struct percpu_counter   *orphan_count;
1096 
1097         struct request_sock_ops *rsk_prot;
1098         struct timewait_sock_ops *twsk_prot;
1099 
1100         union {
1101                 struct inet_hashinfo    *hashinfo;
1102                 struct udp_table        *udp_table;
1103                 struct raw_hashinfo     *raw_hash;
1104                 struct smc_hashinfo     *smc_hash;
1105         } h;
1106 
1107         struct module           *owner;
1108 
1109         char                    name[32];
1110 
1111         struct list_head        node;
1112 #ifdef SOCK_REFCNT_DEBUG
1113         atomic_t                socks;
1114 #endif
1115         int                     (*diag_destroy)(struct sock *sk, int err);
1116 };
1117 
1118 int proto_register(struct proto *prot, int alloc_slab);
1119 void proto_unregister(struct proto *prot);
1120 
1121 #ifdef SOCK_REFCNT_DEBUG
1122 static inline void sk_refcnt_debug_inc(struct sock *sk)
1123 {
1124         atomic_inc(&sk->sk_prot->socks);
1125 }
1126 
1127 static inline void sk_refcnt_debug_dec(struct sock *sk)
1128 {
1129         atomic_dec(&sk->sk_prot->socks);
1130         printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
1131                sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
1132 }
1133 
1134 static inline void sk_refcnt_debug_release(const struct sock *sk)
1135 {
1136         if (atomic_read(&sk->sk_refcnt) != 1)
1137                 printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
1138                        sk->sk_prot->name, sk, atomic_read(&sk->sk_refcnt));
1139 }
1140 #else /* SOCK_REFCNT_DEBUG */
1141 #define sk_refcnt_debug_inc(sk) do { } while (0)
1142 #define sk_refcnt_debug_dec(sk) do { } while (0)
1143 #define sk_refcnt_debug_release(sk) do { } while (0)
1144 #endif /* SOCK_REFCNT_DEBUG */
1145 
1146 static inline bool sk_stream_memory_free(const struct sock *sk)
1147 {
1148         if (sk->sk_wmem_queued >= sk->sk_sndbuf)
1149                 return false;
1150 
1151         return sk->sk_prot->stream_memory_free ?
1152                 sk->sk_prot->stream_memory_free(sk) : true;
1153 }
1154 
1155 static inline bool sk_stream_is_writeable(const struct sock *sk)
1156 {
1157         return sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) &&
1158                sk_stream_memory_free(sk);
1159 }
1160 
1161 static inline int sk_under_cgroup_hierarchy(struct sock *sk,
1162                                             struct cgroup *ancestor)
1163 {
1164 #ifdef CONFIG_SOCK_CGROUP_DATA
1165         return cgroup_is_descendant(sock_cgroup_ptr(&sk->sk_cgrp_data),
1166                                     ancestor);
1167 #else
1168         return -ENOTSUPP;
1169 #endif
1170 }
1171 
1172 static inline bool sk_has_memory_pressure(const struct sock *sk)
1173 {
1174         return sk->sk_prot->memory_pressure != NULL;
1175 }
1176 
1177 static inline bool sk_under_memory_pressure(const struct sock *sk)
1178 {
1179         if (!sk->sk_prot->memory_pressure)
1180                 return false;
1181 
1182         if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
1183             mem_cgroup_under_socket_pressure(sk->sk_memcg))
1184                 return true;
1185 
1186         return !!*sk->sk_prot->memory_pressure;
1187 }
1188 
1189 static inline void sk_leave_memory_pressure(struct sock *sk)
1190 {
1191         int *memory_pressure = sk->sk_prot->memory_pressure;
1192 
1193         if (!memory_pressure)
1194                 return;
1195 
1196         if (*memory_pressure)
1197                 *memory_pressure = 0;
1198 }
1199 
1200 static inline void sk_enter_memory_pressure(struct sock *sk)
1201 {
1202         if (!sk->sk_prot->enter_memory_pressure)
1203                 return;
1204 
1205         sk->sk_prot->enter_memory_pressure(sk);
1206 }
1207 
1208 static inline long
1209 sk_memory_allocated(const struct sock *sk)
1210 {
1211         return atomic_long_read(sk->sk_prot->memory_allocated);
1212 }
1213 
1214 static inline long
1215 sk_memory_allocated_add(struct sock *sk, int amt)
1216 {
1217         return atomic_long_add_return(amt, sk->sk_prot->memory_allocated);
1218 }
1219 
1220 static inline void
1221 sk_memory_allocated_sub(struct sock *sk, int amt)
1222 {
1223         atomic_long_sub(amt, sk->sk_prot->memory_allocated);
1224 }
1225 
1226 static inline void sk_sockets_allocated_dec(struct sock *sk)
1227 {
1228         percpu_counter_dec(sk->sk_prot->sockets_allocated);
1229 }
1230 
1231 static inline void sk_sockets_allocated_inc(struct sock *sk)
1232 {
1233         percpu_counter_inc(sk->sk_prot->sockets_allocated);
1234 }
1235 
1236 static inline int
1237 sk_sockets_allocated_read_positive(struct sock *sk)
1238 {
1239         return percpu_counter_read_positive(sk->sk_prot->sockets_allocated);
1240 }
1241 
1242 static inline int
1243 proto_sockets_allocated_sum_positive(struct proto *prot)
1244 {
1245         return percpu_counter_sum_positive(prot->sockets_allocated);
1246 }
1247 
1248 static inline long
1249 proto_memory_allocated(struct proto *prot)
1250 {
1251         return atomic_long_read(prot->memory_allocated);
1252 }
1253 
1254 static inline bool
1255 proto_memory_pressure(struct proto *prot)
1256 {
1257         if (!prot->memory_pressure)
1258                 return false;
1259         return !!*prot->memory_pressure;
1260 }
1261 
1262 
1263 #ifdef CONFIG_PROC_FS
1264 /* Called with local bh disabled */
1265 void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
1266 int sock_prot_inuse_get(struct net *net, struct proto *proto);
1267 #else
1268 static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
1269                 int inc)
1270 {
1271 }
1272 #endif
1273 
1274 
1275 /* With per-bucket locks this operation is not-atomic, so that
1276  * this version is not worse.
1277  */
1278 static inline int __sk_prot_rehash(struct sock *sk)
1279 {
1280         sk->sk_prot->unhash(sk);
1281         return sk->sk_prot->hash(sk);
1282 }
1283 
1284 /* About 10 seconds */
1285 #define SOCK_DESTROY_TIME (10*HZ)
1286 
1287 /* Sockets 0-1023 can't be bound to unless you are superuser */
1288 #define PROT_SOCK       1024
1289 
1290 #define SHUTDOWN_MASK   3
1291 #define RCV_SHUTDOWN    1
1292 #define SEND_SHUTDOWN   2
1293 
1294 #define SOCK_SNDBUF_LOCK        1
1295 #define SOCK_RCVBUF_LOCK        2
1296 #define SOCK_BINDADDR_LOCK      4
1297 #define SOCK_BINDPORT_LOCK      8
1298 
1299 struct socket_alloc {
1300         struct socket socket;
1301         struct inode vfs_inode;
1302 };
1303 
1304 static inline struct socket *SOCKET_I(struct inode *inode)
1305 {
1306         return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
1307 }
1308 
1309 static inline struct inode *SOCK_INODE(struct socket *socket)
1310 {
1311         return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
1312 }
1313 
1314 /*
1315  * Functions for memory accounting
1316  */
1317 int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind);
1318 int __sk_mem_schedule(struct sock *sk, int size, int kind);
1319 void __sk_mem_reduce_allocated(struct sock *sk, int amount);
1320 void __sk_mem_reclaim(struct sock *sk, int amount);
1321 
1322 /* We used to have PAGE_SIZE here, but systems with 64KB pages
1323  * do not necessarily have 16x time more memory than 4KB ones.
1324  */
1325 #define SK_MEM_QUANTUM 4096
1326 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
1327 #define SK_MEM_SEND     0
1328 #define SK_MEM_RECV     1
1329 
1330 /* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
1331 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
1332 {
1333         long val = sk->sk_prot->sysctl_mem[index];
1334 
1335 #if PAGE_SIZE > SK_MEM_QUANTUM
1336         val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
1337 #elif PAGE_SIZE < SK_MEM_QUANTUM
1338         val >>= SK_MEM_QUANTUM_SHIFT - PAGE_SHIFT;
1339 #endif
1340         return val;
1341 }
1342 
1343 static inline int sk_mem_pages(int amt)
1344 {
1345         return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
1346 }
1347 
1348 static inline bool sk_has_account(struct sock *sk)
1349 {
1350         /* return true if protocol supports memory accounting */
1351         return !!sk->sk_prot->memory_allocated;
1352 }
1353 
1354 static inline bool sk_wmem_schedule(struct sock *sk, int size)
1355 {
1356         if (!sk_has_account(sk))
1357                 return true;
1358         return size <= sk->sk_forward_alloc ||
1359                 __sk_mem_schedule(sk, size, SK_MEM_SEND);
1360 }
1361 
1362 static inline bool
1363 sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
1364 {
1365         if (!sk_has_account(sk))
1366                 return true;
1367         return size<= sk->sk_forward_alloc ||
1368                 __sk_mem_schedule(sk, size, SK_MEM_RECV) ||
1369                 skb_pfmemalloc(skb);
1370 }
1371 
1372 static inline void sk_mem_reclaim(struct sock *sk)
1373 {
1374         if (!sk_has_account(sk))
1375                 return;
1376         if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
1377                 __sk_mem_reclaim(sk, sk->sk_forward_alloc);
1378 }
1379 
1380 static inline void sk_mem_reclaim_partial(struct sock *sk)
1381 {
1382         if (!sk_has_account(sk))
1383                 return;
1384         if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
1385                 __sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);
1386 }
1387 
1388 static inline void sk_mem_charge(struct sock *sk, int size)
1389 {
1390         if (!sk_has_account(sk))
1391                 return;
1392         sk->sk_forward_alloc -= size;
1393 }
1394 
1395 static inline void sk_mem_uncharge(struct sock *sk, int size)
1396 {
1397         if (!sk_has_account(sk))
1398                 return;
1399         sk->sk_forward_alloc += size;
1400 
1401         /* Avoid a possible overflow.
1402          * TCP send queues can make this happen, if sk_mem_reclaim()
1403          * is not called and more than 2 GBytes are released at once.
1404          *
1405          * If we reach 2 MBytes, reclaim 1 MBytes right now, there is
1406          * no need to hold that much forward allocation anyway.
1407          */
1408         if (unlikely(sk->sk_forward_alloc >= 1 << 21))
1409                 __sk_mem_reclaim(sk, 1 << 20);
1410 }
1411 
1412 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
1413 {
1414         sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
1415         sk->sk_wmem_queued -= skb->truesize;
1416         sk_mem_uncharge(sk, skb->truesize);
1417         __kfree_skb(skb);
1418 }
1419 
1420 static inline void sock_release_ownership(struct sock *sk)
1421 {
1422         if (sk->sk_lock.owned) {
1423                 sk->sk_lock.owned = 0;
1424 
1425                 /* The sk_lock has mutex_unlock() semantics: */
1426                 mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
1427         }
1428 }
1429 
1430 /*
1431  * Macro so as to not evaluate some arguments when
1432  * lockdep is not enabled.
1433  *
1434  * Mark both the sk_lock and the sk_lock.slock as a
1435  * per-address-family lock class.
1436  */
1437 #define sock_lock_init_class_and_name(sk, sname, skey, name, key)       \
1438 do {                                                                    \
1439         sk->sk_lock.owned = 0;                                          \
1440         init_waitqueue_head(&sk->sk_lock.wq);                           \
1441         spin_lock_init(&(sk)->sk_lock.slock);                           \
1442         debug_check_no_locks_freed((void *)&(sk)->sk_lock,              \
1443                         sizeof((sk)->sk_lock));                         \
1444         lockdep_set_class_and_name(&(sk)->sk_lock.slock,                \
1445                                 (skey), (sname));                               \
1446         lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);     \
1447 } while (0)
1448 
1449 #ifdef CONFIG_LOCKDEP
1450 static inline bool lockdep_sock_is_held(const struct sock *csk)
1451 {
1452         struct sock *sk = (struct sock *)csk;
1453 
1454         return lockdep_is_held(&sk->sk_lock) ||
1455                lockdep_is_held(&sk->sk_lock.slock);
1456 }
1457 #endif
1458 
1459 void lock_sock_nested(struct sock *sk, int subclass);
1460 
1461 static inline void lock_sock(struct sock *sk)
1462 {
1463         lock_sock_nested(sk, 0);
1464 }
1465 
1466 void release_sock(struct sock *sk);
1467 
1468 /* BH context may only use the following locking interface. */
1469 #define bh_lock_sock(__sk)      spin_lock(&((__sk)->sk_lock.slock))
1470 #define bh_lock_sock_nested(__sk) \
1471                                 spin_lock_nested(&((__sk)->sk_lock.slock), \
1472                                 SINGLE_DEPTH_NESTING)
1473 #define bh_unlock_sock(__sk)    spin_unlock(&((__sk)->sk_lock.slock))
1474 
1475 bool lock_sock_fast(struct sock *sk);
1476 /**
1477  * unlock_sock_fast - complement of lock_sock_fast
1478  * @sk: socket
1479  * @slow: slow mode
1480  *
1481  * fast unlock socket for user context.
1482  * If slow mode is on, we call regular release_sock()
1483  */
1484 static inline void unlock_sock_fast(struct sock *sk, bool slow)
1485 {
1486         if (slow)
1487                 release_sock(sk);
1488         else
1489                 spin_unlock_bh(&sk->sk_lock.slock);
1490 }
1491 
1492 /* Used by processes to "lock" a socket state, so that
1493  * interrupts and bottom half handlers won't change it
1494  * from under us. It essentially blocks any incoming
1495  * packets, so that we won't get any new data or any
1496  * packets that change the state of the socket.
1497  *
1498  * While locked, BH processing will add new packets to
1499  * the backlog queue.  This queue is processed by the
1500  * owner of the socket lock right before it is released.
1501  *
1502  * Since ~2.3.5 it is also exclusive sleep lock serializing
1503  * accesses from user process context.
1504  */
1505 
1506 static inline void sock_owned_by_me(const struct sock *sk)
1507 {
1508 #ifdef CONFIG_LOCKDEP
1509         WARN_ON_ONCE(!lockdep_sock_is_held(sk) && debug_locks);
1510 #endif
1511 }
1512 
1513 static inline bool sock_owned_by_user(const struct sock *sk)
1514 {
1515         sock_owned_by_me(sk);
1516         return sk->sk_lock.owned;
1517 }
1518 
1519 /* no reclassification while locks are held */
1520 static inline bool sock_allow_reclassification(const struct sock *csk)
1521 {
1522         struct sock *sk = (struct sock *)csk;
1523 
1524         return !sk->sk_lock.owned && !spin_is_locked(&sk->sk_lock.slock);
1525 }
1526 
1527 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
1528                       struct proto *prot, int kern);
1529 void sk_free(struct sock *sk);
1530 void sk_destruct(struct sock *sk);
1531 struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority);
1532 void sk_free_unlock_clone(struct sock *sk);
1533 
1534 struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
1535                              gfp_t priority);
1536 void __sock_wfree(struct sk_buff *skb);
1537 void sock_wfree(struct sk_buff *skb);
1538 void skb_orphan_partial(struct sk_buff *skb);
1539 void sock_rfree(struct sk_buff *skb);
1540 void sock_efree(struct sk_buff *skb);
1541 #ifdef CONFIG_INET
1542 void sock_edemux(struct sk_buff *skb);
1543 #else
1544 #define sock_edemux sock_efree
1545 #endif
1546 
1547 int sock_setsockopt(struct socket *sock, int level, int op,
1548                     char __user *optval, unsigned int optlen);
1549 
1550 int sock_getsockopt(struct socket *sock, int level, int op,
1551                     char __user *optval, int __user *optlen);
1552 struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size,
1553                                     int noblock, int *errcode);
1554 struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
1555                                      unsigned long data_len, int noblock,
1556                                      int *errcode, int max_page_order);
1557 void *sock_kmalloc(struct sock *sk, int size, gfp_t priority);
1558 void sock_kfree_s(struct sock *sk, void *mem, int size);
1559 void sock_kzfree_s(struct sock *sk, void *mem, int size);
1560 void sk_send_sigurg(struct sock *sk);
1561 
1562 struct sockcm_cookie {
1563         u32 mark;
1564         u16 tsflags;
1565 };
1566 
1567 int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
1568                      struct sockcm_cookie *sockc);
1569 int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
1570                    struct sockcm_cookie *sockc);
1571 
1572 /*
1573  * Functions to fill in entries in struct proto_ops when a protocol
1574  * does not implement a particular function.
1575  */
1576 int sock_no_bind(struct socket *, struct sockaddr *, int);
1577 int sock_no_connect(struct socket *, struct sockaddr *, int, int);
1578 int sock_no_socketpair(struct socket *, struct socket *);
1579 int sock_no_accept(struct socket *, struct socket *, int, bool);
1580 int sock_no_getname(struct socket *, struct sockaddr *, int *, int);
1581 unsigned int sock_no_poll(struct file *, struct socket *,
1582                           struct poll_table_struct *);
1583 int sock_no_ioctl(struct socket *, unsigned int, unsigned long);
1584 int sock_no_listen(struct socket *, int);
1585 int sock_no_shutdown(struct socket *, int);
1586 int sock_no_getsockopt(struct socket *, int , int, char __user *, int __user *);
1587 int sock_no_setsockopt(struct socket *, int, int, char __user *, unsigned int);
1588 int sock_no_sendmsg(struct socket *, struct msghdr *, size_t);
1589 int sock_no_recvmsg(struct socket *, struct msghdr *, size_t, int);
1590 int sock_no_mmap(struct file *file, struct socket *sock,
1591                  struct vm_area_struct *vma);
1592 ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset,
1593                          size_t size, int flags);
1594 
1595 /*
1596  * Functions to fill in entries in struct proto_ops when a protocol
1597  * uses the inet style.
1598  */
1599 int sock_common_getsockopt(struct socket *sock, int level, int optname,
1600                                   char __user *optval, int __user *optlen);
1601 int sock_common_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1602                         int flags);
1603 int sock_common_setsockopt(struct socket *sock, int level, int optname,
1604                                   char __user *optval, unsigned int optlen);
1605 int compat_sock_common_getsockopt(struct socket *sock, int level,
1606                 int optname, char __user *optval, int __user *optlen);
1607 int compat_sock_common_setsockopt(struct socket *sock, int level,
1608                 int optname, char __user *optval, unsigned int optlen);
1609 
1610 void sk_common_release(struct sock *sk);
1611 
1612 /*
1613  *      Default socket callbacks and setup code
1614  */
1615 
1616 /* Initialise core socket variables */
1617 void sock_init_data(struct socket *sock, struct sock *sk);
1618 
1619 /*
1620  * Socket reference counting postulates.
1621  *
1622  * * Each user of socket SHOULD hold a reference count.
1623  * * Each access point to socket (an hash table bucket, reference from a list,
1624  *   running timer, skb in flight MUST hold a reference count.
1625  * * When reference count hits 0, it means it will never increase back.
1626  * * When reference count hits 0, it means that no references from
1627  *   outside exist to this socket and current process on current CPU
1628  *   is last user and may/should destroy this socket.
1629  * * sk_free is called from any context: process, BH, IRQ. When
1630  *   it is called, socket has no references from outside -> sk_free
1631  *   may release descendant resources allocated by the socket, but
1632  *   to the time when it is called, socket is NOT referenced by any
1633  *   hash tables, lists etc.
1634  * * Packets, delivered from outside (from network or from another process)
1635  *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1636  *   when they sit in queue. Otherwise, packets will leak to hole, when
1637  *   socket is looked up by one cpu and unhasing is made by another CPU.
1638  *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1639  *   (leak to backlog). Packet socket does all the processing inside
1640  *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1641  *   use separate SMP lock, so that they are prone too.
1642  */
1643 
1644 /* Ungrab socket and destroy it, if it was the last reference. */
1645 static inline void sock_put(struct sock *sk)
1646 {
1647         if (atomic_dec_and_test(&sk->sk_refcnt))
1648                 sk_free(sk);
1649 }
1650 /* Generic version of sock_put(), dealing with all sockets
1651  * (TCP_TIMEWAIT, TCP_NEW_SYN_RECV, ESTABLISHED...)
1652  */
1653 void sock_gen_put(struct sock *sk);
1654 
1655 int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested,
1656                      unsigned int trim_cap, bool refcounted);
1657 static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
1658                                  const int nested)
1659 {
1660         return __sk_receive_skb(sk, skb, nested, 1, true);
1661 }
1662 
1663 static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
1664 {
1665         sk->sk_tx_queue_mapping = tx_queue;
1666 }
1667 
1668 static inline void sk_tx_queue_clear(struct sock *sk)
1669 {
1670         sk->sk_tx_queue_mapping = -1;
1671 }
1672 
1673 static inline int sk_tx_queue_get(const struct sock *sk)
1674 {
1675         return sk ? sk->sk_tx_queue_mapping : -1;
1676 }
1677 
1678 static inline void sk_set_socket(struct sock *sk, struct socket *sock)
1679 {
1680         sk_tx_queue_clear(sk);
1681         sk->sk_socket = sock;
1682 }
1683 
1684 static inline wait_queue_head_t *sk_sleep(struct sock *sk)
1685 {
1686         BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
1687         return &rcu_dereference_raw(sk->sk_wq)->wait;
1688 }
1689 /* Detach socket from process context.
1690  * Announce socket dead, detach it from wait queue and inode.
1691  * Note that parent inode held reference count on this struct sock,
1692  * we do not release it in this function, because protocol
1693  * probably wants some additional cleanups or even continuing
1694  * to work with this socket (TCP).
1695  */
1696 static inline void sock_orphan(struct sock *sk)
1697 {
1698         write_lock_bh(&sk->sk_callback_lock);
1699         sock_set_flag(sk, SOCK_DEAD);
1700         sk_set_socket(sk, NULL);
1701         sk->sk_wq  = NULL;
1702         write_unlock_bh(&sk->sk_callback_lock);
1703 }
1704 
1705 static inline void sock_graft(struct sock *sk, struct socket *parent)
1706 {
1707         write_lock_bh(&sk->sk_callback_lock);
1708         sk->sk_wq = parent->wq;
1709         parent->sk = sk;
1710         sk_set_socket(sk, parent);
1711         sk->sk_uid = SOCK_INODE(parent)->i_uid;
1712         security_sock_graft(sk, parent);
1713         write_unlock_bh(&sk->sk_callback_lock);
1714 }
1715 
1716 kuid_t sock_i_uid(struct sock *sk);
1717 unsigned long sock_i_ino(struct sock *sk);
1718 
1719 static inline kuid_t sock_net_uid(const struct net *net, const struct sock *sk)
1720 {
1721         return sk ? sk->sk_uid : make_kuid(net->user_ns, 0);
1722 }
1723 
1724 static inline u32 net_tx_rndhash(void)
1725 {
1726         u32 v = prandom_u32();
1727 
1728         return v ?: 1;
1729 }
1730 
1731 static inline void sk_set_txhash(struct sock *sk)
1732 {
1733         sk->sk_txhash = net_tx_rndhash();
1734 }
1735 
1736 static inline void sk_rethink_txhash(struct sock *sk)
1737 {
1738         if (sk->sk_txhash)
1739                 sk_set_txhash(sk);
1740 }
1741 
1742 static inline struct dst_entry *
1743 __sk_dst_get(struct sock *sk)
1744 {
1745         return rcu_dereference_check(sk->sk_dst_cache,
1746                                      lockdep_sock_is_held(sk));
1747 }
1748 
1749 static inline struct dst_entry *
1750 sk_dst_get(struct sock *sk)
1751 {
1752         struct dst_entry *dst;
1753 
1754         rcu_read_lock();
1755         dst = rcu_dereference(sk->sk_dst_cache);
1756         if (dst && !atomic_inc_not_zero(&dst->__refcnt))
1757                 dst = NULL;
1758         rcu_read_unlock();
1759         return dst;
1760 }
1761 
1762 static inline void dst_negative_advice(struct sock *sk)
1763 {
1764         struct dst_entry *ndst, *dst = __sk_dst_get(sk);
1765 
1766         sk_rethink_txhash(sk);
1767 
1768         if (dst && dst->ops->negative_advice) {
1769                 ndst = dst->ops->negative_advice(dst);
1770 
1771                 if (ndst != dst) {
1772                         rcu_assign_pointer(sk->sk_dst_cache, ndst);
1773                         sk_tx_queue_clear(sk);
1774                         sk->sk_dst_pending_confirm = 0;
1775                 }
1776         }
1777 }
1778 
1779 static inline void
1780 __sk_dst_set(struct sock *sk, struct dst_entry *dst)
1781 {
1782         struct dst_entry *old_dst;
1783 
1784         sk_tx_queue_clear(sk);
1785         sk->sk_dst_pending_confirm = 0;
1786         old_dst = rcu_dereference_protected(sk->sk_dst_cache,
1787                                             lockdep_sock_is_held(sk));
1788         rcu_assign_pointer(sk->sk_dst_cache, dst);
1789         dst_release(old_dst);
1790 }
1791 
1792 static inline void
1793 sk_dst_set(struct sock *sk, struct dst_entry *dst)
1794 {
1795         struct dst_entry *old_dst;
1796 
1797         sk_tx_queue_clear(sk);
1798         sk->sk_dst_pending_confirm = 0;
1799         old_dst = xchg((__force struct dst_entry **)&sk->sk_dst_cache, dst);
1800         dst_release(old_dst);
1801 }
1802 
1803 static inline void
1804 __sk_dst_reset(struct sock *sk)
1805 {
1806         __sk_dst_set(sk, NULL);
1807 }
1808 
1809 static inline void
1810 sk_dst_reset(struct sock *sk)
1811 {
1812         sk_dst_set(sk, NULL);
1813 }
1814 
1815 struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
1816 
1817 struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
1818 
1819 static inline void sk_dst_confirm(struct sock *sk)
1820 {
1821         if (!sk->sk_dst_pending_confirm)
1822                 sk->sk_dst_pending_confirm = 1;
1823 }
1824 
1825 static inline void sock_confirm_neigh(struct sk_buff *skb, struct neighbour *n)
1826 {
1827         if (skb_get_dst_pending_confirm(skb)) {
1828                 struct sock *sk = skb->sk;
1829                 unsigned long now = jiffies;
1830 
1831                 /* avoid dirtying neighbour */
1832                 if (n->confirmed != now)
1833                         n->confirmed = now;
1834                 if (sk && sk->sk_dst_pending_confirm)
1835                         sk->sk_dst_pending_confirm = 0;
1836         }
1837 }
1838 
1839 bool sk_mc_loop(struct sock *sk);
1840 
1841 static inline bool sk_can_gso(const struct sock *sk)
1842 {
1843         return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
1844 }
1845 
1846 void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
1847 
1848 static inline void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
1849 {
1850         sk->sk_route_nocaps |= flags;
1851         sk->sk_route_caps &= ~flags;
1852 }
1853 
1854 static inline bool sk_check_csum_caps(struct sock *sk)
1855 {
1856         return (sk->sk_route_caps & NETIF_F_HW_CSUM) ||
1857                (sk->sk_family == PF_INET &&
1858                 (sk->sk_route_caps & NETIF_F_IP_CSUM)) ||
1859                (sk->sk_family == PF_INET6 &&
1860                 (sk->sk_route_caps & NETIF_F_IPV6_CSUM));
1861 }
1862 
1863 static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
1864                                            struct iov_iter *from, char *to,
1865                                            int copy, int offset)
1866 {
1867         if (skb->ip_summed == CHECKSUM_NONE) {
1868                 __wsum csum = 0;
1869                 if (!csum_and_copy_from_iter_full(to, copy, &csum, from))
1870                         return -EFAULT;
1871                 skb->csum = csum_block_add(skb->csum, csum, offset);
1872         } else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1873                 if (!copy_from_iter_full_nocache(to, copy, from))
1874                         return -EFAULT;
1875         } else if (!copy_from_iter_full(to, copy, from))
1876                 return -EFAULT;
1877 
1878         return 0;
1879 }
1880 
1881 static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
1882                                        struct iov_iter *from, int copy)
1883 {
1884         int err, offset = skb->len;
1885 
1886         err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
1887                                        copy, offset);
1888         if (err)
1889                 __skb_trim(skb, offset);
1890 
1891         return err;
1892 }
1893 
1894 static inline int skb_copy_to_page_nocache(struct sock *sk, struct iov_iter *from,
1895                                            struct sk_buff *skb,
1896                                            struct page *page,
1897                                            int off, int copy)
1898 {
1899         int err;
1900 
1901         err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
1902                                        copy, skb->len);
1903         if (err)
1904                 return err;
1905 
1906         skb->len             += copy;
1907         skb->data_len        += copy;
1908         skb->truesize        += copy;
1909         sk->sk_wmem_queued   += copy;
1910         sk_mem_charge(sk, copy);
1911         return 0;
1912 }
1913 
1914 /**
1915  * sk_wmem_alloc_get - returns write allocations
1916  * @sk: socket
1917  *
1918  * Returns sk_wmem_alloc minus initial offset of one
1919  */
1920 static inline int sk_wmem_alloc_get(const struct sock *sk)
1921 {
1922         return atomic_read(&sk->sk_wmem_alloc) - 1;
1923 }
1924 
1925 /**
1926  * sk_rmem_alloc_get - returns read allocations
1927  * @sk: socket
1928  *
1929  * Returns sk_rmem_alloc
1930  */
1931 static inline int sk_rmem_alloc_get(const struct sock *sk)
1932 {
1933         return atomic_read(&sk->sk_rmem_alloc);
1934 }
1935 
1936 /**
1937  * sk_has_allocations - check if allocations are outstanding
1938  * @sk: socket
1939  *
1940  * Returns true if socket has write or read allocations
1941  */
1942 static inline bool sk_has_allocations(const struct sock *sk)
1943 {
1944         return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
1945 }
1946 
1947 /**
1948  * skwq_has_sleeper - check if there are any waiting processes
1949  * @wq: struct socket_wq
1950  *
1951  * Returns true if socket_wq has waiting processes
1952  *
1953  * The purpose of the skwq_has_sleeper and sock_poll_wait is to wrap the memory
1954  * barrier call. They were added due to the race found within the tcp code.
1955  *
1956  * Consider following tcp code paths:
1957  *
1958  * CPU1                  CPU2
1959  *
1960  * sys_select            receive packet
1961  *   ...                 ...
1962  *   __add_wait_queue    update tp->rcv_nxt
1963  *   ...                 ...
1964  *   tp->rcv_nxt check   sock_def_readable
1965  *   ...                 {
1966  *   schedule               rcu_read_lock();
1967  *                          wq = rcu_dereference(sk->sk_wq);
1968  *                          if (wq && waitqueue_active(&wq->wait))
1969  *                              wake_up_interruptible(&wq->wait)
1970  *                          ...
1971  *                       }
1972  *
1973  * The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
1974  * in its cache, and so does the tp->rcv_nxt update on CPU2 side.  The CPU1
1975  * could then endup calling schedule and sleep forever if there are no more
1976  * data on the socket.
1977  *
1978  */
1979 static inline bool skwq_has_sleeper(struct socket_wq *wq)
1980 {
1981         return wq && wq_has_sleeper(&wq->wait);
1982 }
1983 
1984 /**
1985  * sock_poll_wait - place memory barrier behind the poll_wait call.
1986  * @filp:           file
1987  * @wait_address:   socket wait queue
1988  * @p:              poll_table
1989  *
1990  * See the comments in the wq_has_sleeper function.
1991  */
1992 static inline void sock_poll_wait(struct file *filp,
1993                 wait_queue_head_t *wait_address, poll_table *p)
1994 {
1995         if (!poll_does_not_wait(p) && wait_address) {
1996                 poll_wait(filp, wait_address, p);
1997                 /* We need to be sure we are in sync with the
1998                  * socket flags modification.
1999                  *
2000                  * This memory barrier is paired in the wq_has_sleeper.
2001                  */
2002                 smp_mb();
2003         }
2004 }
2005 
2006 static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)
2007 {
2008         if (sk->sk_txhash) {
2009                 skb->l4_hash = 1;
2010                 skb->hash = sk->sk_txhash;
2011         }
2012 }
2013 
2014 void skb_set_owner_w(struct sk_buff *skb, struct sock *sk);
2015 
2016 /*
2017  *      Queue a received datagram if it will fit. Stream and sequenced
2018  *      protocols can't normally use this as they need to fit buffers in
2019  *      and play with them.
2020  *
2021  *      Inlined as it's very short and called for pretty much every
2022  *      packet ever received.
2023  */
2024 static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
2025 {
2026         skb_orphan(skb);
2027         skb->sk = sk;
2028         skb->destructor = sock_rfree;
2029         atomic_add(skb->truesize, &sk->sk_rmem_alloc);
2030         sk_mem_charge(sk, skb->truesize);
2031 }
2032 
2033 void sk_reset_timer(struct sock *sk, struct timer_list *timer,
2034                     unsigned long expires);
2035 
2036 void sk_stop_timer(struct sock *sk, struct timer_list *timer);
2037 
2038 int __sk_queue_drop_skb(struct sock *sk, struct sk_buff *skb,
2039                         unsigned int flags,
2040                         void (*destructor)(struct sock *sk,
2041                                            struct sk_buff *skb));
2042 int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2043 int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2044 
2045 int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
2046 struct sk_buff *sock_dequeue_err_skb(struct sock *sk);
2047 
2048 /*
2049  *      Recover an error report and clear atomically
2050  */
2051 
2052 static inline int sock_error(struct sock *sk)
2053 {
2054         int err;
2055         if (likely(!sk->sk_err))
2056                 return 0;
2057         err = xchg(&sk->sk_err, 0);
2058         return -err;
2059 }
2060 
2061 static inline unsigned long sock_wspace(struct sock *sk)
2062 {
2063         int amt = 0;
2064 
2065         if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
2066                 amt = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
2067                 if (amt < 0)
2068                         amt = 0;
2069         }
2070         return amt;
2071 }
2072 
2073 /* Note:
2074  *  We use sk->sk_wq_raw, from contexts knowing this
2075  *  pointer is not NULL and cannot disappear/change.
2076  */
2077 static inline void sk_set_bit(int nr, struct sock *sk)
2078 {
2079         if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
2080             !sock_flag(sk, SOCK_FASYNC))
2081                 return;
2082 
2083         set_bit(nr, &sk->sk_wq_raw->flags);
2084 }
2085 
2086 static inline void sk_clear_bit(int nr, struct sock *sk)
2087 {
2088         if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
2089             !sock_flag(sk, SOCK_FASYNC))
2090                 return;
2091 
2092         clear_bit(nr, &sk->sk_wq_raw->flags);
2093 }
2094 
2095 static inline void sk_wake_async(const struct sock *sk, int how, int band)
2096 {
2097         if (sock_flag(sk, SOCK_FASYNC)) {
2098                 rcu_read_lock();
2099                 sock_wake_async(rcu_dereference(sk->sk_wq), how, band);
2100                 rcu_read_unlock();
2101         }
2102 }
2103 
2104 /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might
2105  * need sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak.
2106  * Note: for send buffers, TCP works better if we can build two skbs at
2107  * minimum.
2108  */
2109 #define TCP_SKB_MIN_TRUESIZE    (2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
2110 
2111 #define SOCK_MIN_SNDBUF         (TCP_SKB_MIN_TRUESIZE * 2)
2112 #define SOCK_MIN_RCVBUF          TCP_SKB_MIN_TRUESIZE
2113 
2114 static inline void sk_stream_moderate_sndbuf(struct sock *sk)
2115 {
2116         if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
2117                 sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
2118                 sk->sk_sndbuf = max_t(u32, sk->sk_sndbuf, SOCK_MIN_SNDBUF);
2119         }
2120 }
2121 
2122 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
2123                                     bool force_schedule);
2124 
2125 /**
2126  * sk_page_frag - return an appropriate page_frag
2127  * @sk: socket
2128  *
2129  * If socket allocation mode allows current thread to sleep, it means its
2130  * safe to use the per task page_frag instead of the per socket one.
2131  */
2132 static inline struct page_frag *sk_page_frag(struct sock *sk)
2133 {
2134         if (gfpflags_allow_blocking(sk->sk_allocation))
2135                 return &current->task_frag;
2136 
2137         return &sk->sk_frag;
2138 }
2139 
2140 bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag);
2141 
2142 /*
2143  *      Default write policy as shown to user space via poll/select/SIGIO
2144  */
2145 static inline bool sock_writeable(const struct sock *sk)
2146 {
2147         return atomic_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
2148 }
2149 
2150 static inline gfp_t gfp_any(void)
2151 {
2152         return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
2153 }
2154 
2155 static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
2156 {
2157         return noblock ? 0 : sk->sk_rcvtimeo;
2158 }
2159 
2160 static inline long sock_sndtimeo(const struct sock *sk, bool noblock)
2161 {
2162         return noblock ? 0 : sk->sk_sndtimeo;
2163 }
2164 
2165 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
2166 {
2167         return (waitall ? len : min_t(int, sk->sk_rcvlowat, len)) ? : 1;
2168 }
2169 
2170 /* Alas, with timeout socket operations are not restartable.
2171  * Compare this to poll().
2172  */
2173 static inline int sock_intr_errno(long timeo)
2174 {
2175         return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
2176 }
2177 
2178 struct sock_skb_cb {
2179         u32 dropcount;
2180 };
2181 
2182 /* Store sock_skb_cb at the end of skb->cb[] so protocol families
2183  * using skb->cb[] would keep using it directly and utilize its
2184  * alignement guarantee.
2185  */
2186 #define SOCK_SKB_CB_OFFSET ((FIELD_SIZEOF(struct sk_buff, cb) - \
2187                             sizeof(struct sock_skb_cb)))
2188 
2189 #define SOCK_SKB_CB(__skb) ((struct sock_skb_cb *)((__skb)->cb + \
2190                             SOCK_SKB_CB_OFFSET))
2191 
2192 #define sock_skb_cb_check_size(size) \
2193         BUILD_BUG_ON((size) > SOCK_SKB_CB_OFFSET)
2194 
2195 static inline void
2196 sock_skb_set_dropcount(const struct sock *sk, struct sk_buff *skb)
2197 {
2198         SOCK_SKB_CB(skb)->dropcount = sock_flag(sk, SOCK_RXQ_OVFL) ?
2199                                                 atomic_read(&sk->sk_drops) : 0;
2200 }
2201 
2202 static inline void sk_drops_add(struct sock *sk, const struct sk_buff *skb)
2203 {
2204         int segs = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
2205 
2206         atomic_add(segs, &sk->sk_drops);
2207 }
2208 
2209 void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
2210                            struct sk_buff *skb);
2211 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
2212                              struct sk_buff *skb);
2213 
2214 static inline void
2215 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
2216 {
2217         ktime_t kt = skb->tstamp;
2218         struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
2219 
2220         /*
2221          * generate control messages if
2222          * - receive time stamping in software requested
2223          * - software time stamp available and wanted
2224          * - hardware time stamps available and wanted
2225          */
2226         if (sock_flag(sk, SOCK_RCVTSTAMP) ||
2227             (sk->sk_tsflags & SOF_TIMESTAMPING_RX_SOFTWARE) ||
2228             (kt && sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) ||
2229             (hwtstamps->hwtstamp &&
2230              (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
2231                 __sock_recv_timestamp(msg, sk, skb);
2232         else
2233                 sk->sk_stamp = kt;
2234 
2235         if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
2236                 __sock_recv_wifi_status(msg, sk, skb);
2237 }
2238 
2239 void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2240                               struct sk_buff *skb);
2241 
2242 #define SK_DEFAULT_STAMP (-1L * NSEC_PER_SEC)
2243 static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2244                                           struct sk_buff *skb)
2245 {
2246 #define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)                       | \
2247                            (1UL << SOCK_RCVTSTAMP))
2248 #define TSFLAGS_ANY       (SOF_TIMESTAMPING_SOFTWARE                    | \
2249                            SOF_TIMESTAMPING_RAW_HARDWARE)
2250 
2251         if (sk->sk_flags & FLAGS_TS_OR_DROPS || sk->sk_tsflags & TSFLAGS_ANY)
2252                 __sock_recv_ts_and_drops(msg, sk, skb);
2253         else if (unlikely(sock_flag(sk, SOCK_TIMESTAMP)))
2254                 sk->sk_stamp = skb->tstamp;
2255         else if (unlikely(sk->sk_stamp == SK_DEFAULT_STAMP))
2256                 sk->sk_stamp = 0;
2257 }
2258 
2259 void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags);
2260 
2261 /**
2262  * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
2263  * @sk:         socket sending this packet
2264  * @tsflags:    timestamping flags to use
2265  * @tx_flags:   completed with instructions for time stamping
2266  *
2267  * Note : callers should take care of initial *tx_flags value (usually 0)
2268  */
2269 static inline void sock_tx_timestamp(const struct sock *sk, __u16 tsflags,
2270                                      __u8 *tx_flags)
2271 {
2272         if (unlikely(tsflags))
2273                 __sock_tx_timestamp(tsflags, tx_flags);
2274         if (unlikely(sock_flag(sk, SOCK_WIFI_STATUS)))
2275                 *tx_flags |= SKBTX_WIFI_STATUS;
2276 }
2277 
2278 /**
2279  * sk_eat_skb - Release a skb if it is no longer needed
2280  * @sk: socket to eat this skb from
2281  * @skb: socket buffer to eat
2282  *
2283  * This routine must be called with interrupts disabled or with the socket
2284  * locked so that the sk_buff queue operation is ok.
2285 */
2286 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb)
2287 {
2288         __skb_unlink(skb, &sk->sk_receive_queue);
2289         __kfree_skb(skb);
2290 }
2291 
2292 static inline
2293 struct net *sock_net(const struct sock *sk)
2294 {
2295         return read_pnet(&sk->sk_net);
2296 }
2297 
2298 static inline
2299 void sock_net_set(struct sock *sk, struct net *net)
2300 {
2301         write_pnet(&sk->sk_net, net);
2302 }
2303 
2304 static inline struct sock *skb_steal_sock(struct sk_buff *skb)
2305 {
2306         if (skb->sk) {
2307                 struct sock *sk = skb->sk;
2308 
2309                 skb->destructor = NULL;
2310                 skb->sk = NULL;
2311                 return sk;
2312         }
2313         return NULL;
2314 }
2315 
2316 /* This helper checks if a socket is a full socket,
2317  * ie _not_ a timewait or request socket.
2318  */
2319 static inline bool sk_fullsock(const struct sock *sk)
2320 {
2321         return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
2322 }
2323 
2324 /* This helper checks if a socket is a LISTEN or NEW_SYN_RECV
2325  * SYNACK messages can be attached to either ones (depending on SYNCOOKIE)
2326  */
2327 static inline bool sk_listener(const struct sock *sk)
2328 {
2329         return (1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV);
2330 }
2331 
2332 /**
2333  * sk_state_load - read sk->sk_state for lockless contexts
2334  * @sk: socket pointer
2335  *
2336  * Paired with sk_state_store(). Used in places we do not hold socket lock :
2337  * tcp_diag_get_info(), tcp_get_info(), tcp_poll(), get_tcp4_sock() ...
2338  */
2339 static inline int sk_state_load(const struct sock *sk)
2340 {
2341         return smp_load_acquire(&sk->sk_state);
2342 }
2343 
2344 /**
2345  * sk_state_store - update sk->sk_state
2346  * @sk: socket pointer
2347  * @newstate: new state
2348  *
2349  * Paired with sk_state_load(). Should be used in contexts where
2350  * state change might impact lockless readers.
2351  */
2352 static inline void sk_state_store(struct sock *sk, int newstate)
2353 {
2354         smp_store_release(&sk->sk_state, newstate);
2355 }
2356 
2357 void sock_enable_timestamp(struct sock *sk, int flag);
2358 int sock_get_timestamp(struct sock *, struct timeval __user *);
2359 int sock_get_timestampns(struct sock *, struct timespec __user *);
2360 int sock_recv_errqueue(struct sock *sk, struct msghdr *msg, int len, int level,
2361                        int type);
2362 
2363 bool sk_ns_capable(const struct sock *sk,
2364                    struct user_namespace *user_ns, int cap);
2365 bool sk_capable(const struct sock *sk, int cap);
2366 bool sk_net_capable(const struct sock *sk, int cap);
2367 
2368 void sk_get_meminfo(const struct sock *sk, u32 *meminfo);
2369 
2370 extern __u32 sysctl_wmem_max;
2371 extern __u32 sysctl_rmem_max;
2372 
2373 extern int sysctl_tstamp_allow_data;
2374 extern int sysctl_optmem_max;
2375 
2376 extern __u32 sysctl_wmem_default;
2377 extern __u32 sysctl_rmem_default;
2378 
2379 #endif  /* _SOCK_H */
2380 

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