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Linux/include/net/sock.h

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

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