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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 
 62 #include <linux/filter.h>
 63 #include <linux/rculist_nulls.h>
 64 #include <linux/poll.h>
 65 
 66 #include <linux/atomic.h>
 67 #include <net/dst.h>
 68 #include <net/checksum.h>
 69 #include <net/tcp_states.h>
 70 #include <linux/net_tstamp.h>
 71 
 72 struct cgroup;
 73 struct cgroup_subsys;
 74 #ifdef CONFIG_NET
 75 int mem_cgroup_sockets_init(struct mem_cgroup *memcg, struct cgroup_subsys *ss);
 76 void mem_cgroup_sockets_destroy(struct mem_cgroup *memcg);
 77 #else
 78 static inline
 79 int mem_cgroup_sockets_init(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
 80 {
 81         return 0;
 82 }
 83 static inline
 84 void mem_cgroup_sockets_destroy(struct mem_cgroup *memcg)
 85 {
 86 }
 87 #endif
 88 /*
 89  * This structure really needs to be cleaned up.
 90  * Most of it is for TCP, and not used by any of
 91  * the other protocols.
 92  */
 93 
 94 /* Define this to get the SOCK_DBG debugging facility. */
 95 #define SOCK_DEBUGGING
 96 #ifdef SOCK_DEBUGGING
 97 #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
 98                                         printk(KERN_DEBUG msg); } while (0)
 99 #else
100 /* Validate arguments and do nothing */
101 static inline __printf(2, 3)
102 void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)
103 {
104 }
105 #endif
106 
107 /* This is the per-socket lock.  The spinlock provides a synchronization
108  * between user contexts and software interrupt processing, whereas the
109  * mini-semaphore synchronizes multiple users amongst themselves.
110  */
111 typedef struct {
112         spinlock_t              slock;
113         int                     owned;
114         wait_queue_head_t       wq;
115         /*
116          * We express the mutex-alike socket_lock semantics
117          * to the lock validator by explicitly managing
118          * the slock as a lock variant (in addition to
119          * the slock itself):
120          */
121 #ifdef CONFIG_DEBUG_LOCK_ALLOC
122         struct lockdep_map dep_map;
123 #endif
124 } socket_lock_t;
125 
126 struct sock;
127 struct proto;
128 struct net;
129 
130 typedef __u32 __bitwise __portpair;
131 typedef __u64 __bitwise __addrpair;
132 
133 /**
134  *      struct sock_common - minimal network layer representation of sockets
135  *      @skc_daddr: Foreign IPv4 addr
136  *      @skc_rcv_saddr: Bound local IPv4 addr
137  *      @skc_hash: hash value used with various protocol lookup tables
138  *      @skc_u16hashes: two u16 hash values used by UDP lookup tables
139  *      @skc_dport: placeholder for inet_dport/tw_dport
140  *      @skc_num: placeholder for inet_num/tw_num
141  *      @skc_family: network address family
142  *      @skc_state: Connection state
143  *      @skc_reuse: %SO_REUSEADDR setting
144  *      @skc_reuseport: %SO_REUSEPORT setting
145  *      @skc_bound_dev_if: bound device index if != 0
146  *      @skc_bind_node: bind hash linkage for various protocol lookup tables
147  *      @skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
148  *      @skc_prot: protocol handlers inside a network family
149  *      @skc_net: reference to the network namespace of this socket
150  *      @skc_node: main hash linkage for various protocol lookup tables
151  *      @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
152  *      @skc_tx_queue_mapping: tx queue number for this connection
153  *      @skc_refcnt: reference count
154  *
155  *      This is the minimal network layer representation of sockets, the header
156  *      for struct sock and struct inet_timewait_sock.
157  */
158 struct sock_common {
159         /* skc_daddr and skc_rcv_saddr must be grouped on a 8 bytes aligned
160          * address on 64bit arches : cf INET_MATCH()
161          */
162         union {
163                 __addrpair      skc_addrpair;
164                 struct {
165                         __be32  skc_daddr;
166                         __be32  skc_rcv_saddr;
167                 };
168         };
169         union  {
170                 unsigned int    skc_hash;
171                 __u16           skc_u16hashes[2];
172         };
173         /* skc_dport && skc_num must be grouped as well */
174         union {
175                 __portpair      skc_portpair;
176                 struct {
177                         __be16  skc_dport;
178                         __u16   skc_num;
179                 };
180         };
181 
182         unsigned short          skc_family;
183         volatile unsigned char  skc_state;
184         unsigned char           skc_reuse:4;
185         unsigned char           skc_reuseport:1;
186         unsigned char           skc_ipv6only:1;
187         unsigned char           skc_net_refcnt:1;
188         int                     skc_bound_dev_if;
189         union {
190                 struct hlist_node       skc_bind_node;
191                 struct hlist_nulls_node skc_portaddr_node;
192         };
193         struct proto            *skc_prot;
194         possible_net_t          skc_net;
195 
196 #if IS_ENABLED(CONFIG_IPV6)
197         struct in6_addr         skc_v6_daddr;
198         struct in6_addr         skc_v6_rcv_saddr;
199 #endif
200 
201         atomic64_t              skc_cookie;
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         atomic_t                skc_refcnt;
216         /* private: */
217         int                     skc_dontcopy_end[0];
218         /* public: */
219 };
220 
221 struct cg_proto;
222 /**
223   *     struct sock - network layer representation of sockets
224   *     @__sk_common: shared layout with inet_timewait_sock
225   *     @sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
226   *     @sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
227   *     @sk_lock:       synchronizer
228   *     @sk_rcvbuf: size of receive buffer in bytes
229   *     @sk_wq: sock wait queue and async head
230   *     @sk_rx_dst: receive input route used by early demux
231   *     @sk_dst_cache: destination cache
232   *     @sk_dst_lock: destination cache lock
233   *     @sk_policy: flow policy
234   *     @sk_receive_queue: incoming packets
235   *     @sk_wmem_alloc: transmit queue bytes committed
236   *     @sk_write_queue: Packet sending queue
237   *     @sk_omem_alloc: "o" is "option" or "other"
238   *     @sk_wmem_queued: persistent queue size
239   *     @sk_forward_alloc: space allocated forward
240   *     @sk_napi_id: id of the last napi context to receive data for sk
241   *     @sk_ll_usec: usecs to busypoll when there is no data
242   *     @sk_allocation: allocation mode
243   *     @sk_pacing_rate: Pacing rate (if supported by transport/packet scheduler)
244   *     @sk_max_pacing_rate: Maximum pacing rate (%SO_MAX_PACING_RATE)
245   *     @sk_sndbuf: size of send buffer in bytes
246   *     @sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
247   *                %SO_OOBINLINE settings, %SO_TIMESTAMPING settings
248   *     @sk_no_check_tx: %SO_NO_CHECK setting, set checksum in TX packets
249   *     @sk_no_check_rx: allow zero checksum in RX packets
250   *     @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
251   *     @sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)
252   *     @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
253   *     @sk_gso_max_size: Maximum GSO segment size to build
254   *     @sk_gso_max_segs: Maximum number of GSO segments
255   *     @sk_lingertime: %SO_LINGER l_linger setting
256   *     @sk_backlog: always used with the per-socket spinlock held
257   *     @sk_callback_lock: used with the callbacks in the end of this struct
258   *     @sk_error_queue: rarely used
259   *     @sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
260   *                       IPV6_ADDRFORM for instance)
261   *     @sk_err: last error
262   *     @sk_err_soft: errors that don't cause failure but are the cause of a
263   *                   persistent failure not just 'timed out'
264   *     @sk_drops: raw/udp drops counter
265   *     @sk_ack_backlog: current listen backlog
266   *     @sk_max_ack_backlog: listen backlog set in listen()
267   *     @sk_priority: %SO_PRIORITY setting
268   *     @sk_cgrp_prioidx: socket group's priority map index
269   *     @sk_type: socket type (%SOCK_STREAM, etc)
270   *     @sk_protocol: which protocol this socket belongs in this network family
271   *     @sk_peer_pid: &struct pid for this socket's peer
272   *     @sk_peer_cred: %SO_PEERCRED setting
273   *     @sk_rcvlowat: %SO_RCVLOWAT setting
274   *     @sk_rcvtimeo: %SO_RCVTIMEO setting
275   *     @sk_sndtimeo: %SO_SNDTIMEO setting
276   *     @sk_rxhash: flow hash received from netif layer
277   *     @sk_incoming_cpu: record cpu processing incoming packets
278   *     @sk_txhash: computed flow hash for use on transmit
279   *     @sk_filter: socket filtering instructions
280   *     @sk_timer: sock cleanup timer
281   *     @sk_stamp: time stamp of last packet received
282   *     @sk_tsflags: SO_TIMESTAMPING socket options
283   *     @sk_tskey: counter to disambiguate concurrent tstamp requests
284   *     @sk_socket: Identd and reporting IO signals
285   *     @sk_user_data: RPC layer private data
286   *     @sk_frag: cached page frag
287   *     @sk_peek_off: current peek_offset value
288   *     @sk_send_head: front of stuff to transmit
289   *     @sk_security: used by security modules
290   *     @sk_mark: generic packet mark
291   *     @sk_classid: this socket's cgroup classid
292   *     @sk_cgrp: this socket's cgroup-specific proto data
293   *     @sk_write_pending: a write to stream socket waits to start
294   *     @sk_state_change: callback to indicate change in the state of the sock
295   *     @sk_data_ready: callback to indicate there is data to be processed
296   *     @sk_write_space: callback to indicate there is bf sending space available
297   *     @sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
298   *     @sk_backlog_rcv: callback to process the backlog
299   *     @sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
300  */
301 struct sock {
302         /*
303          * Now struct inet_timewait_sock also uses sock_common, so please just
304          * don't add nothing before this first member (__sk_common) --acme
305          */
306         struct sock_common      __sk_common;
307 #define sk_node                 __sk_common.skc_node
308 #define sk_nulls_node           __sk_common.skc_nulls_node
309 #define sk_refcnt               __sk_common.skc_refcnt
310 #define sk_tx_queue_mapping     __sk_common.skc_tx_queue_mapping
311 
312 #define sk_dontcopy_begin       __sk_common.skc_dontcopy_begin
313 #define sk_dontcopy_end         __sk_common.skc_dontcopy_end
314 #define sk_hash                 __sk_common.skc_hash
315 #define sk_portpair             __sk_common.skc_portpair
316 #define sk_num                  __sk_common.skc_num
317 #define sk_dport                __sk_common.skc_dport
318 #define sk_addrpair             __sk_common.skc_addrpair
319 #define sk_daddr                __sk_common.skc_daddr
320 #define sk_rcv_saddr            __sk_common.skc_rcv_saddr
321 #define sk_family               __sk_common.skc_family
322 #define sk_state                __sk_common.skc_state
323 #define sk_reuse                __sk_common.skc_reuse
324 #define sk_reuseport            __sk_common.skc_reuseport
325 #define sk_ipv6only             __sk_common.skc_ipv6only
326 #define sk_net_refcnt           __sk_common.skc_net_refcnt
327 #define sk_bound_dev_if         __sk_common.skc_bound_dev_if
328 #define sk_bind_node            __sk_common.skc_bind_node
329 #define sk_prot                 __sk_common.skc_prot
330 #define sk_net                  __sk_common.skc_net
331 #define sk_v6_daddr             __sk_common.skc_v6_daddr
332 #define sk_v6_rcv_saddr __sk_common.skc_v6_rcv_saddr
333 #define sk_cookie               __sk_common.skc_cookie
334 
335         socket_lock_t           sk_lock;
336         struct sk_buff_head     sk_receive_queue;
337         /*
338          * The backlog queue is special, it is always used with
339          * the per-socket spinlock held and requires low latency
340          * access. Therefore we special case it's implementation.
341          * Note : rmem_alloc is in this structure to fill a hole
342          * on 64bit arches, not because its logically part of
343          * backlog.
344          */
345         struct {
346                 atomic_t        rmem_alloc;
347                 int             len;
348                 struct sk_buff  *head;
349                 struct sk_buff  *tail;
350         } sk_backlog;
351 #define sk_rmem_alloc sk_backlog.rmem_alloc
352         int                     sk_forward_alloc;
353 #ifdef CONFIG_RPS
354         __u32                   sk_rxhash;
355 #endif
356         u16                     sk_incoming_cpu;
357         /* 16bit hole
358          * Warned : sk_incoming_cpu can be set from softirq,
359          * Do not use this hole without fully understanding possible issues.
360          */
361 
362         __u32                   sk_txhash;
363 #ifdef CONFIG_NET_RX_BUSY_POLL
364         unsigned int            sk_napi_id;
365         unsigned int            sk_ll_usec;
366 #endif
367         atomic_t                sk_drops;
368         int                     sk_rcvbuf;
369 
370         struct sk_filter __rcu  *sk_filter;
371         struct socket_wq __rcu  *sk_wq;
372 
373 #ifdef CONFIG_XFRM
374         struct xfrm_policy      *sk_policy[2];
375 #endif
376         unsigned long           sk_flags;
377         struct dst_entry        *sk_rx_dst;
378         struct dst_entry __rcu  *sk_dst_cache;
379         spinlock_t              sk_dst_lock;
380         atomic_t                sk_wmem_alloc;
381         atomic_t                sk_omem_alloc;
382         int                     sk_sndbuf;
383         struct sk_buff_head     sk_write_queue;
384         kmemcheck_bitfield_begin(flags);
385         unsigned int            sk_shutdown  : 2,
386                                 sk_no_check_tx : 1,
387                                 sk_no_check_rx : 1,
388                                 sk_userlocks : 4,
389                                 sk_protocol  : 8,
390 #define SK_PROTOCOL_MAX U8_MAX
391                                 sk_type      : 16;
392         kmemcheck_bitfield_end(flags);
393         int                     sk_wmem_queued;
394         gfp_t                   sk_allocation;
395         u32                     sk_pacing_rate; /* bytes per second */
396         u32                     sk_max_pacing_rate;
397         netdev_features_t       sk_route_caps;
398         netdev_features_t       sk_route_nocaps;
399         int                     sk_gso_type;
400         unsigned int            sk_gso_max_size;
401         u16                     sk_gso_max_segs;
402         int                     sk_rcvlowat;
403         unsigned long           sk_lingertime;
404         struct sk_buff_head     sk_error_queue;
405         struct proto            *sk_prot_creator;
406         rwlock_t                sk_callback_lock;
407         int                     sk_err,
408                                 sk_err_soft;
409         u32                     sk_ack_backlog;
410         u32                     sk_max_ack_backlog;
411         __u32                   sk_priority;
412 #if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
413         __u32                   sk_cgrp_prioidx;
414 #endif
415         struct pid              *sk_peer_pid;
416         const struct cred       *sk_peer_cred;
417         long                    sk_rcvtimeo;
418         long                    sk_sndtimeo;
419         struct timer_list       sk_timer;
420         ktime_t                 sk_stamp;
421         u16                     sk_tsflags;
422         u32                     sk_tskey;
423         struct socket           *sk_socket;
424         void                    *sk_user_data;
425         struct page_frag        sk_frag;
426         struct sk_buff          *sk_send_head;
427         __s32                   sk_peek_off;
428         int                     sk_write_pending;
429 #ifdef CONFIG_SECURITY
430         void                    *sk_security;
431 #endif
432         __u32                   sk_mark;
433 #ifdef CONFIG_CGROUP_NET_CLASSID
434         u32                     sk_classid;
435 #endif
436         struct cg_proto         *sk_cgrp;
437         void                    (*sk_state_change)(struct sock *sk);
438         void                    (*sk_data_ready)(struct sock *sk);
439         void                    (*sk_write_space)(struct sock *sk);
440         void                    (*sk_error_report)(struct sock *sk);
441         int                     (*sk_backlog_rcv)(struct sock *sk,
442                                                   struct sk_buff *skb);
443         void                    (*sk_destruct)(struct sock *sk);
444 };
445 
446 #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data)))
447 
448 #define rcu_dereference_sk_user_data(sk)        rcu_dereference(__sk_user_data((sk)))
449 #define rcu_assign_sk_user_data(sk, ptr)        rcu_assign_pointer(__sk_user_data((sk)), ptr)
450 
451 /*
452  * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
453  * or not whether his port will be reused by someone else. SK_FORCE_REUSE
454  * on a socket means that the socket will reuse everybody else's port
455  * without looking at the other's sk_reuse value.
456  */
457 
458 #define SK_NO_REUSE     0
459 #define SK_CAN_REUSE    1
460 #define SK_FORCE_REUSE  2
461 
462 static inline int sk_peek_offset(struct sock *sk, int flags)
463 {
464         if ((flags & MSG_PEEK) && (sk->sk_peek_off >= 0))
465                 return sk->sk_peek_off;
466         else
467                 return 0;
468 }
469 
470 static inline void sk_peek_offset_bwd(struct sock *sk, int val)
471 {
472         if (sk->sk_peek_off >= 0) {
473                 if (sk->sk_peek_off >= val)
474                         sk->sk_peek_off -= val;
475                 else
476                         sk->sk_peek_off = 0;
477         }
478 }
479 
480 static inline void sk_peek_offset_fwd(struct sock *sk, int val)
481 {
482         if (sk->sk_peek_off >= 0)
483                 sk->sk_peek_off += val;
484 }
485 
486 /*
487  * Hashed lists helper routines
488  */
489 static inline struct sock *sk_entry(const struct hlist_node *node)
490 {
491         return hlist_entry(node, struct sock, sk_node);
492 }
493 
494 static inline struct sock *__sk_head(const struct hlist_head *head)
495 {
496         return hlist_entry(head->first, struct sock, sk_node);
497 }
498 
499 static inline struct sock *sk_head(const struct hlist_head *head)
500 {
501         return hlist_empty(head) ? NULL : __sk_head(head);
502 }
503 
504 static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
505 {
506         return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
507 }
508 
509 static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
510 {
511         return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
512 }
513 
514 static inline struct sock *sk_next(const struct sock *sk)
515 {
516         return sk->sk_node.next ?
517                 hlist_entry(sk->sk_node.next, struct sock, sk_node) : NULL;
518 }
519 
520 static inline struct sock *sk_nulls_next(const struct sock *sk)
521 {
522         return (!is_a_nulls(sk->sk_nulls_node.next)) ?
523                 hlist_nulls_entry(sk->sk_nulls_node.next,
524                                   struct sock, sk_nulls_node) :
525                 NULL;
526 }
527 
528 static inline bool sk_unhashed(const struct sock *sk)
529 {
530         return hlist_unhashed(&sk->sk_node);
531 }
532 
533 static inline bool sk_hashed(const struct sock *sk)
534 {
535         return !sk_unhashed(sk);
536 }
537 
538 static inline void sk_node_init(struct hlist_node *node)
539 {
540         node->pprev = NULL;
541 }
542 
543 static inline void sk_nulls_node_init(struct hlist_nulls_node *node)
544 {
545         node->pprev = NULL;
546 }
547 
548 static inline void __sk_del_node(struct sock *sk)
549 {
550         __hlist_del(&sk->sk_node);
551 }
552 
553 /* NB: equivalent to hlist_del_init_rcu */
554 static inline bool __sk_del_node_init(struct sock *sk)
555 {
556         if (sk_hashed(sk)) {
557                 __sk_del_node(sk);
558                 sk_node_init(&sk->sk_node);
559                 return true;
560         }
561         return false;
562 }
563 
564 /* Grab socket reference count. This operation is valid only
565    when sk is ALREADY grabbed f.e. it is found in hash table
566    or a list and the lookup is made under lock preventing hash table
567    modifications.
568  */
569 
570 static inline void sock_hold(struct sock *sk)
571 {
572         atomic_inc(&sk->sk_refcnt);
573 }
574 
575 /* Ungrab socket in the context, which assumes that socket refcnt
576    cannot hit zero, f.e. it is true in context of any socketcall.
577  */
578 static inline void __sock_put(struct sock *sk)
579 {
580         atomic_dec(&sk->sk_refcnt);
581 }
582 
583 static inline bool sk_del_node_init(struct sock *sk)
584 {
585         bool rc = __sk_del_node_init(sk);
586 
587         if (rc) {
588                 /* paranoid for a while -acme */
589                 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
590                 __sock_put(sk);
591         }
592         return rc;
593 }
594 #define sk_del_node_init_rcu(sk)        sk_del_node_init(sk)
595 
596 static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)
597 {
598         if (sk_hashed(sk)) {
599                 hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
600                 return true;
601         }
602         return false;
603 }
604 
605 static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
606 {
607         bool rc = __sk_nulls_del_node_init_rcu(sk);
608 
609         if (rc) {
610                 /* paranoid for a while -acme */
611                 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
612                 __sock_put(sk);
613         }
614         return rc;
615 }
616 
617 static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)
618 {
619         hlist_add_head(&sk->sk_node, list);
620 }
621 
622 static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
623 {
624         sock_hold(sk);
625         __sk_add_node(sk, list);
626 }
627 
628 static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
629 {
630         sock_hold(sk);
631         hlist_add_head_rcu(&sk->sk_node, list);
632 }
633 
634 static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
635 {
636         hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
637 }
638 
639 static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
640 {
641         sock_hold(sk);
642         __sk_nulls_add_node_rcu(sk, list);
643 }
644 
645 static inline void __sk_del_bind_node(struct sock *sk)
646 {
647         __hlist_del(&sk->sk_bind_node);
648 }
649 
650 static inline void sk_add_bind_node(struct sock *sk,
651                                         struct hlist_head *list)
652 {
653         hlist_add_head(&sk->sk_bind_node, list);
654 }
655 
656 #define sk_for_each(__sk, list) \
657         hlist_for_each_entry(__sk, list, sk_node)
658 #define sk_for_each_rcu(__sk, list) \
659         hlist_for_each_entry_rcu(__sk, list, sk_node)
660 #define sk_nulls_for_each(__sk, node, list) \
661         hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
662 #define sk_nulls_for_each_rcu(__sk, node, list) \
663         hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
664 #define sk_for_each_from(__sk) \
665         hlist_for_each_entry_from(__sk, sk_node)
666 #define sk_nulls_for_each_from(__sk, node) \
667         if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
668                 hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
669 #define sk_for_each_safe(__sk, tmp, list) \
670         hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
671 #define sk_for_each_bound(__sk, list) \
672         hlist_for_each_entry(__sk, list, sk_bind_node)
673 
674 /**
675  * sk_nulls_for_each_entry_offset - iterate over a list at a given struct offset
676  * @tpos:       the type * to use as a loop cursor.
677  * @pos:        the &struct hlist_node to use as a loop cursor.
678  * @head:       the head for your list.
679  * @offset:     offset of hlist_node within the struct.
680  *
681  */
682 #define sk_nulls_for_each_entry_offset(tpos, pos, head, offset)                \
683         for (pos = (head)->first;                                              \
684              (!is_a_nulls(pos)) &&                                             \
685                 ({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;});       \
686              pos = pos->next)
687 
688 static inline struct user_namespace *sk_user_ns(struct sock *sk)
689 {
690         /* Careful only use this in a context where these parameters
691          * can not change and must all be valid, such as recvmsg from
692          * userspace.
693          */
694         return sk->sk_socket->file->f_cred->user_ns;
695 }
696 
697 /* Sock flags */
698 enum sock_flags {
699         SOCK_DEAD,
700         SOCK_DONE,
701         SOCK_URGINLINE,
702         SOCK_KEEPOPEN,
703         SOCK_LINGER,
704         SOCK_DESTROY,
705         SOCK_BROADCAST,
706         SOCK_TIMESTAMP,
707         SOCK_ZAPPED,
708         SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
709         SOCK_DBG, /* %SO_DEBUG setting */
710         SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
711         SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
712         SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
713         SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
714         SOCK_MEMALLOC, /* VM depends on this socket for swapping */
715         SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
716         SOCK_FASYNC, /* fasync() active */
717         SOCK_RXQ_OVFL,
718         SOCK_ZEROCOPY, /* buffers from userspace */
719         SOCK_WIFI_STATUS, /* push wifi status to userspace */
720         SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
721                      * Will use last 4 bytes of packet sent from
722                      * user-space instead.
723                      */
724         SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
725         SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
726 };
727 
728 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
729 
730 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
731 {
732         nsk->sk_flags = osk->sk_flags;
733 }
734 
735 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
736 {
737         __set_bit(flag, &sk->sk_flags);
738 }
739 
740 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
741 {
742         __clear_bit(flag, &sk->sk_flags);
743 }
744 
745 static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
746 {
747         return test_bit(flag, &sk->sk_flags);
748 }
749 
750 #ifdef CONFIG_NET
751 extern struct static_key memalloc_socks;
752 static inline int sk_memalloc_socks(void)
753 {
754         return static_key_false(&memalloc_socks);
755 }
756 #else
757 
758 static inline int sk_memalloc_socks(void)
759 {
760         return 0;
761 }
762 
763 #endif
764 
765 static inline gfp_t sk_gfp_atomic(struct sock *sk, gfp_t gfp_mask)
766 {
767         return GFP_ATOMIC | (sk->sk_allocation & __GFP_MEMALLOC);
768 }
769 
770 static inline void sk_acceptq_removed(struct sock *sk)
771 {
772         sk->sk_ack_backlog--;
773 }
774 
775 static inline void sk_acceptq_added(struct sock *sk)
776 {
777         sk->sk_ack_backlog++;
778 }
779 
780 static inline bool sk_acceptq_is_full(const struct sock *sk)
781 {
782         return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
783 }
784 
785 /*
786  * Compute minimal free write space needed to queue new packets.
787  */
788 static inline int sk_stream_min_wspace(const struct sock *sk)
789 {
790         return sk->sk_wmem_queued >> 1;
791 }
792 
793 static inline int sk_stream_wspace(const struct sock *sk)
794 {
795         return sk->sk_sndbuf - sk->sk_wmem_queued;
796 }
797 
798 void sk_stream_write_space(struct sock *sk);
799 
800 /* OOB backlog add */
801 static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
802 {
803         /* dont let skb dst not refcounted, we are going to leave rcu lock */
804         skb_dst_force_safe(skb);
805 
806         if (!sk->sk_backlog.tail)
807                 sk->sk_backlog.head = skb;
808         else
809                 sk->sk_backlog.tail->next = skb;
810 
811         sk->sk_backlog.tail = skb;
812         skb->next = NULL;
813 }
814 
815 /*
816  * Take into account size of receive queue and backlog queue
817  * Do not take into account this skb truesize,
818  * to allow even a single big packet to come.
819  */
820 static inline bool sk_rcvqueues_full(const struct sock *sk, unsigned int limit)
821 {
822         unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
823 
824         return qsize > limit;
825 }
826 
827 /* The per-socket spinlock must be held here. */
828 static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
829                                               unsigned int limit)
830 {
831         if (sk_rcvqueues_full(sk, limit))
832                 return -ENOBUFS;
833 
834         /*
835          * If the skb was allocated from pfmemalloc reserves, only
836          * allow SOCK_MEMALLOC sockets to use it as this socket is
837          * helping free memory
838          */
839         if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
840                 return -ENOMEM;
841 
842         __sk_add_backlog(sk, skb);
843         sk->sk_backlog.len += skb->truesize;
844         return 0;
845 }
846 
847 int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
848 
849 static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
850 {
851         if (sk_memalloc_socks() && skb_pfmemalloc(skb))
852                 return __sk_backlog_rcv(sk, skb);
853 
854         return sk->sk_backlog_rcv(sk, skb);
855 }
856 
857 static inline void sk_incoming_cpu_update(struct sock *sk)
858 {
859         sk->sk_incoming_cpu = raw_smp_processor_id();
860 }
861 
862 static inline void sock_rps_record_flow_hash(__u32 hash)
863 {
864 #ifdef CONFIG_RPS
865         struct rps_sock_flow_table *sock_flow_table;
866 
867         rcu_read_lock();
868         sock_flow_table = rcu_dereference(rps_sock_flow_table);
869         rps_record_sock_flow(sock_flow_table, hash);
870         rcu_read_unlock();
871 #endif
872 }
873 
874 static inline void sock_rps_record_flow(const struct sock *sk)
875 {
876 #ifdef CONFIG_RPS
877         sock_rps_record_flow_hash(sk->sk_rxhash);
878 #endif
879 }
880 
881 static inline void sock_rps_save_rxhash(struct sock *sk,
882                                         const struct sk_buff *skb)
883 {
884 #ifdef CONFIG_RPS
885         if (unlikely(sk->sk_rxhash != skb->hash))
886                 sk->sk_rxhash = skb->hash;
887 #endif
888 }
889 
890 static inline void sock_rps_reset_rxhash(struct sock *sk)
891 {
892 #ifdef CONFIG_RPS
893         sk->sk_rxhash = 0;
894 #endif
895 }
896 
897 #define sk_wait_event(__sk, __timeo, __condition)                       \
898         ({      int __rc;                                               \
899                 release_sock(__sk);                                     \
900                 __rc = __condition;                                     \
901                 if (!__rc) {                                            \
902                         *(__timeo) = schedule_timeout(*(__timeo));      \
903                 }                                                       \
904                 sched_annotate_sleep();                                         \
905                 lock_sock(__sk);                                        \
906                 __rc = __condition;                                     \
907                 __rc;                                                   \
908         })
909 
910 int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
911 int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
912 void sk_stream_wait_close(struct sock *sk, long timeo_p);
913 int sk_stream_error(struct sock *sk, int flags, int err);
914 void sk_stream_kill_queues(struct sock *sk);
915 void sk_set_memalloc(struct sock *sk);
916 void sk_clear_memalloc(struct sock *sk);
917 
918 int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb);
919 
920 struct request_sock_ops;
921 struct timewait_sock_ops;
922 struct inet_hashinfo;
923 struct raw_hashinfo;
924 struct module;
925 
926 /*
927  * caches using SLAB_DESTROY_BY_RCU should let .next pointer from nulls nodes
928  * un-modified. Special care is taken when initializing object to zero.
929  */
930 static inline void sk_prot_clear_nulls(struct sock *sk, int size)
931 {
932         if (offsetof(struct sock, sk_node.next) != 0)
933                 memset(sk, 0, offsetof(struct sock, sk_node.next));
934         memset(&sk->sk_node.pprev, 0,
935                size - offsetof(struct sock, sk_node.pprev));
936 }
937 
938 /* Networking protocol blocks we attach to sockets.
939  * socket layer -> transport layer interface
940  */
941 struct proto {
942         void                    (*close)(struct sock *sk,
943                                         long timeout);
944         int                     (*connect)(struct sock *sk,
945                                         struct sockaddr *uaddr,
946                                         int addr_len);
947         int                     (*disconnect)(struct sock *sk, int flags);
948 
949         struct sock *           (*accept)(struct sock *sk, int flags, int *err);
950 
951         int                     (*ioctl)(struct sock *sk, int cmd,
952                                          unsigned long arg);
953         int                     (*init)(struct sock *sk);
954         void                    (*destroy)(struct sock *sk);
955         void                    (*shutdown)(struct sock *sk, int how);
956         int                     (*setsockopt)(struct sock *sk, int level,
957                                         int optname, char __user *optval,
958                                         unsigned int optlen);
959         int                     (*getsockopt)(struct sock *sk, int level,
960                                         int optname, char __user *optval,
961                                         int __user *option);
962 #ifdef CONFIG_COMPAT
963         int                     (*compat_setsockopt)(struct sock *sk,
964                                         int level,
965                                         int optname, char __user *optval,
966                                         unsigned int optlen);
967         int                     (*compat_getsockopt)(struct sock *sk,
968                                         int level,
969                                         int optname, char __user *optval,
970                                         int __user *option);
971         int                     (*compat_ioctl)(struct sock *sk,
972                                         unsigned int cmd, unsigned long arg);
973 #endif
974         int                     (*sendmsg)(struct sock *sk, struct msghdr *msg,
975                                            size_t len);
976         int                     (*recvmsg)(struct sock *sk, struct msghdr *msg,
977                                            size_t len, int noblock, int flags,
978                                            int *addr_len);
979         int                     (*sendpage)(struct sock *sk, struct page *page,
980                                         int offset, size_t size, int flags);
981         int                     (*bind)(struct sock *sk,
982                                         struct sockaddr *uaddr, int addr_len);
983 
984         int                     (*backlog_rcv) (struct sock *sk,
985                                                 struct sk_buff *skb);
986 
987         void            (*release_cb)(struct sock *sk);
988 
989         /* Keeping track of sk's, looking them up, and port selection methods. */
990         void                    (*hash)(struct sock *sk);
991         void                    (*unhash)(struct sock *sk);
992         void                    (*rehash)(struct sock *sk);
993         int                     (*get_port)(struct sock *sk, unsigned short snum);
994         void                    (*clear_sk)(struct sock *sk, int size);
995 
996         /* Keeping track of sockets in use */
997 #ifdef CONFIG_PROC_FS
998         unsigned int            inuse_idx;
999 #endif
1000 
1001         bool                    (*stream_memory_free)(const struct sock *sk);
1002         /* Memory pressure */
1003         void                    (*enter_memory_pressure)(struct sock *sk);
1004         atomic_long_t           *memory_allocated;      /* Current allocated memory. */
1005         struct percpu_counter   *sockets_allocated;     /* Current number of sockets. */
1006         /*
1007          * Pressure flag: try to collapse.
1008          * Technical note: it is used by multiple contexts non atomically.
1009          * All the __sk_mem_schedule() is of this nature: accounting
1010          * is strict, actions are advisory and have some latency.
1011          */
1012         int                     *memory_pressure;
1013         long                    *sysctl_mem;
1014         int                     *sysctl_wmem;
1015         int                     *sysctl_rmem;
1016         int                     max_header;
1017         bool                    no_autobind;
1018 
1019         struct kmem_cache       *slab;
1020         unsigned int            obj_size;
1021         int                     slab_flags;
1022 
1023         struct percpu_counter   *orphan_count;
1024 
1025         struct request_sock_ops *rsk_prot;
1026         struct timewait_sock_ops *twsk_prot;
1027 
1028         union {
1029                 struct inet_hashinfo    *hashinfo;
1030                 struct udp_table        *udp_table;
1031                 struct raw_hashinfo     *raw_hash;
1032         } h;
1033 
1034         struct module           *owner;
1035 
1036         char                    name[32];
1037 
1038         struct list_head        node;
1039 #ifdef SOCK_REFCNT_DEBUG
1040         atomic_t                socks;
1041 #endif
1042 #ifdef CONFIG_MEMCG_KMEM
1043         /*
1044          * cgroup specific init/deinit functions. Called once for all
1045          * protocols that implement it, from cgroups populate function.
1046          * This function has to setup any files the protocol want to
1047          * appear in the kmem cgroup filesystem.
1048          */
1049         int                     (*init_cgroup)(struct mem_cgroup *memcg,
1050                                                struct cgroup_subsys *ss);
1051         void                    (*destroy_cgroup)(struct mem_cgroup *memcg);
1052         struct cg_proto         *(*proto_cgroup)(struct mem_cgroup *memcg);
1053 #endif
1054 };
1055 
1056 int proto_register(struct proto *prot, int alloc_slab);
1057 void proto_unregister(struct proto *prot);
1058 
1059 #ifdef SOCK_REFCNT_DEBUG
1060 static inline void sk_refcnt_debug_inc(struct sock *sk)
1061 {
1062         atomic_inc(&sk->sk_prot->socks);
1063 }
1064 
1065 static inline void sk_refcnt_debug_dec(struct sock *sk)
1066 {
1067         atomic_dec(&sk->sk_prot->socks);
1068         printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
1069                sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
1070 }
1071 
1072 static inline void sk_refcnt_debug_release(const struct sock *sk)
1073 {
1074         if (atomic_read(&sk->sk_refcnt) != 1)
1075                 printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
1076                        sk->sk_prot->name, sk, atomic_read(&sk->sk_refcnt));
1077 }
1078 #else /* SOCK_REFCNT_DEBUG */
1079 #define sk_refcnt_debug_inc(sk) do { } while (0)
1080 #define sk_refcnt_debug_dec(sk) do { } while (0)
1081 #define sk_refcnt_debug_release(sk) do { } while (0)
1082 #endif /* SOCK_REFCNT_DEBUG */
1083 
1084 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_NET)
1085 extern struct static_key memcg_socket_limit_enabled;
1086 static inline struct cg_proto *parent_cg_proto(struct proto *proto,
1087                                                struct cg_proto *cg_proto)
1088 {
1089         return proto->proto_cgroup(parent_mem_cgroup(cg_proto->memcg));
1090 }
1091 #define mem_cgroup_sockets_enabled static_key_false(&memcg_socket_limit_enabled)
1092 #else
1093 #define mem_cgroup_sockets_enabled 0
1094 static inline struct cg_proto *parent_cg_proto(struct proto *proto,
1095                                                struct cg_proto *cg_proto)
1096 {
1097         return NULL;
1098 }
1099 #endif
1100 
1101 static inline bool sk_stream_memory_free(const struct sock *sk)
1102 {
1103         if (sk->sk_wmem_queued >= sk->sk_sndbuf)
1104                 return false;
1105 
1106         return sk->sk_prot->stream_memory_free ?
1107                 sk->sk_prot->stream_memory_free(sk) : true;
1108 }
1109 
1110 static inline bool sk_stream_is_writeable(const struct sock *sk)
1111 {
1112         return sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) &&
1113                sk_stream_memory_free(sk);
1114 }
1115 
1116 
1117 static inline bool sk_has_memory_pressure(const struct sock *sk)
1118 {
1119         return sk->sk_prot->memory_pressure != NULL;
1120 }
1121 
1122 static inline bool sk_under_memory_pressure(const struct sock *sk)
1123 {
1124         if (!sk->sk_prot->memory_pressure)
1125                 return false;
1126 
1127         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1128                 return !!sk->sk_cgrp->memory_pressure;
1129 
1130         return !!*sk->sk_prot->memory_pressure;
1131 }
1132 
1133 static inline void sk_leave_memory_pressure(struct sock *sk)
1134 {
1135         int *memory_pressure = sk->sk_prot->memory_pressure;
1136 
1137         if (!memory_pressure)
1138                 return;
1139 
1140         if (*memory_pressure)
1141                 *memory_pressure = 0;
1142 
1143         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1144                 struct cg_proto *cg_proto = sk->sk_cgrp;
1145                 struct proto *prot = sk->sk_prot;
1146 
1147                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1148                         cg_proto->memory_pressure = 0;
1149         }
1150 
1151 }
1152 
1153 static inline void sk_enter_memory_pressure(struct sock *sk)
1154 {
1155         if (!sk->sk_prot->enter_memory_pressure)
1156                 return;
1157 
1158         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1159                 struct cg_proto *cg_proto = sk->sk_cgrp;
1160                 struct proto *prot = sk->sk_prot;
1161 
1162                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1163                         cg_proto->memory_pressure = 1;
1164         }
1165 
1166         sk->sk_prot->enter_memory_pressure(sk);
1167 }
1168 
1169 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
1170 {
1171         long *prot = sk->sk_prot->sysctl_mem;
1172         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1173                 prot = sk->sk_cgrp->sysctl_mem;
1174         return prot[index];
1175 }
1176 
1177 static inline void memcg_memory_allocated_add(struct cg_proto *prot,
1178                                               unsigned long amt,
1179                                               int *parent_status)
1180 {
1181         page_counter_charge(&prot->memory_allocated, amt);
1182 
1183         if (page_counter_read(&prot->memory_allocated) >
1184             prot->memory_allocated.limit)
1185                 *parent_status = OVER_LIMIT;
1186 }
1187 
1188 static inline void memcg_memory_allocated_sub(struct cg_proto *prot,
1189                                               unsigned long amt)
1190 {
1191         page_counter_uncharge(&prot->memory_allocated, amt);
1192 }
1193 
1194 static inline long
1195 sk_memory_allocated(const struct sock *sk)
1196 {
1197         struct proto *prot = sk->sk_prot;
1198 
1199         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1200                 return page_counter_read(&sk->sk_cgrp->memory_allocated);
1201 
1202         return atomic_long_read(prot->memory_allocated);
1203 }
1204 
1205 static inline long
1206 sk_memory_allocated_add(struct sock *sk, int amt, int *parent_status)
1207 {
1208         struct proto *prot = sk->sk_prot;
1209 
1210         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1211                 memcg_memory_allocated_add(sk->sk_cgrp, amt, parent_status);
1212                 /* update the root cgroup regardless */
1213                 atomic_long_add_return(amt, prot->memory_allocated);
1214                 return page_counter_read(&sk->sk_cgrp->memory_allocated);
1215         }
1216 
1217         return atomic_long_add_return(amt, prot->memory_allocated);
1218 }
1219 
1220 static inline void
1221 sk_memory_allocated_sub(struct sock *sk, int amt)
1222 {
1223         struct proto *prot = sk->sk_prot;
1224 
1225         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1226                 memcg_memory_allocated_sub(sk->sk_cgrp, amt);
1227 
1228         atomic_long_sub(amt, prot->memory_allocated);
1229 }
1230 
1231 static inline void sk_sockets_allocated_dec(struct sock *sk)
1232 {
1233         struct proto *prot = sk->sk_prot;
1234 
1235         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1236                 struct cg_proto *cg_proto = sk->sk_cgrp;
1237 
1238                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1239                         percpu_counter_dec(&cg_proto->sockets_allocated);
1240         }
1241 
1242         percpu_counter_dec(prot->sockets_allocated);
1243 }
1244 
1245 static inline void sk_sockets_allocated_inc(struct sock *sk)
1246 {
1247         struct proto *prot = sk->sk_prot;
1248 
1249         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1250                 struct cg_proto *cg_proto = sk->sk_cgrp;
1251 
1252                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1253                         percpu_counter_inc(&cg_proto->sockets_allocated);
1254         }
1255 
1256         percpu_counter_inc(prot->sockets_allocated);
1257 }
1258 
1259 static inline int
1260 sk_sockets_allocated_read_positive(struct sock *sk)
1261 {
1262         struct proto *prot = sk->sk_prot;
1263 
1264         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1265                 return percpu_counter_read_positive(&sk->sk_cgrp->sockets_allocated);
1266 
1267         return percpu_counter_read_positive(prot->sockets_allocated);
1268 }
1269 
1270 static inline int
1271 proto_sockets_allocated_sum_positive(struct proto *prot)
1272 {
1273         return percpu_counter_sum_positive(prot->sockets_allocated);
1274 }
1275 
1276 static inline long
1277 proto_memory_allocated(struct proto *prot)
1278 {
1279         return atomic_long_read(prot->memory_allocated);
1280 }
1281 
1282 static inline bool
1283 proto_memory_pressure(struct proto *prot)
1284 {
1285         if (!prot->memory_pressure)
1286                 return false;
1287         return !!*prot->memory_pressure;
1288 }
1289 
1290 
1291 #ifdef CONFIG_PROC_FS
1292 /* Called with local bh disabled */
1293 void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
1294 int sock_prot_inuse_get(struct net *net, struct proto *proto);
1295 #else
1296 static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
1297                 int inc)
1298 {
1299 }
1300 #endif
1301 
1302 
1303 /* With per-bucket locks this operation is not-atomic, so that
1304  * this version is not worse.
1305  */
1306 static inline void __sk_prot_rehash(struct sock *sk)
1307 {
1308         sk->sk_prot->unhash(sk);
1309         sk->sk_prot->hash(sk);
1310 }
1311 
1312 void sk_prot_clear_portaddr_nulls(struct sock *sk, int size);
1313 
1314 /* About 10 seconds */
1315 #define SOCK_DESTROY_TIME (10*HZ)
1316 
1317 /* Sockets 0-1023 can't be bound to unless you are superuser */
1318 #define PROT_SOCK       1024
1319 
1320 #define SHUTDOWN_MASK   3
1321 #define RCV_SHUTDOWN    1
1322 #define SEND_SHUTDOWN   2
1323 
1324 #define SOCK_SNDBUF_LOCK        1
1325 #define SOCK_RCVBUF_LOCK        2
1326 #define SOCK_BINDADDR_LOCK      4
1327 #define SOCK_BINDPORT_LOCK      8
1328 
1329 struct socket_alloc {
1330         struct socket socket;
1331         struct inode vfs_inode;
1332 };
1333 
1334 static inline struct socket *SOCKET_I(struct inode *inode)
1335 {
1336         return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
1337 }
1338 
1339 static inline struct inode *SOCK_INODE(struct socket *socket)
1340 {
1341         return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
1342 }
1343 
1344 /*
1345  * Functions for memory accounting
1346  */
1347 int __sk_mem_schedule(struct sock *sk, int size, int kind);
1348 void __sk_mem_reclaim(struct sock *sk, int amount);
1349 
1350 #define SK_MEM_QUANTUM ((int)PAGE_SIZE)
1351 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
1352 #define SK_MEM_SEND     0
1353 #define SK_MEM_RECV     1
1354 
1355 static inline int sk_mem_pages(int amt)
1356 {
1357         return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
1358 }
1359 
1360 static inline bool sk_has_account(struct sock *sk)
1361 {
1362         /* return true if protocol supports memory accounting */
1363         return !!sk->sk_prot->memory_allocated;
1364 }
1365 
1366 static inline bool sk_wmem_schedule(struct sock *sk, int size)
1367 {
1368         if (!sk_has_account(sk))
1369                 return true;
1370         return size <= sk->sk_forward_alloc ||
1371                 __sk_mem_schedule(sk, size, SK_MEM_SEND);
1372 }
1373 
1374 static inline bool
1375 sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
1376 {
1377         if (!sk_has_account(sk))
1378                 return true;
1379         return size<= sk->sk_forward_alloc ||
1380                 __sk_mem_schedule(sk, size, SK_MEM_RECV) ||
1381                 skb_pfmemalloc(skb);
1382 }
1383 
1384 static inline void sk_mem_reclaim(struct sock *sk)
1385 {
1386         if (!sk_has_account(sk))
1387                 return;
1388         if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
1389                 __sk_mem_reclaim(sk, sk->sk_forward_alloc);
1390 }
1391 
1392 static inline void sk_mem_reclaim_partial(struct sock *sk)
1393 {
1394         if (!sk_has_account(sk))
1395                 return;
1396         if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
1397                 __sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);
1398 }
1399 
1400 static inline void sk_mem_charge(struct sock *sk, int size)
1401 {
1402         if (!sk_has_account(sk))
1403                 return;
1404         sk->sk_forward_alloc -= size;
1405 }
1406 
1407 static inline void sk_mem_uncharge(struct sock *sk, int size)
1408 {
1409         if (!sk_has_account(sk))
1410                 return;
1411         sk->sk_forward_alloc += size;
1412 }
1413 
1414 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
1415 {
1416         sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
1417         sk->sk_wmem_queued -= skb->truesize;
1418         sk_mem_uncharge(sk, skb->truesize);
1419         __kfree_skb(skb);
1420 }
1421 
1422 /* Used by processes to "lock" a socket state, so that
1423  * interrupts and bottom half handlers won't change it
1424  * from under us. It essentially blocks any incoming
1425  * packets, so that we won't get any new data or any
1426  * packets that change the state of the socket.
1427  *
1428  * While locked, BH processing will add new packets to
1429  * the backlog queue.  This queue is processed by the
1430  * owner of the socket lock right before it is released.
1431  *
1432  * Since ~2.3.5 it is also exclusive sleep lock serializing
1433  * accesses from user process context.
1434  */
1435 #define sock_owned_by_user(sk)  ((sk)->sk_lock.owned)
1436 
1437 static inline void sock_release_ownership(struct sock *sk)
1438 {
1439         sk->sk_lock.owned = 0;
1440 }
1441 
1442 /*
1443  * Macro so as to not evaluate some arguments when
1444  * lockdep is not enabled.
1445  *
1446  * Mark both the sk_lock and the sk_lock.slock as a
1447  * per-address-family lock class.
1448  */
1449 #define sock_lock_init_class_and_name(sk, sname, skey, name, key)       \
1450 do {                                                                    \
1451         sk->sk_lock.owned = 0;                                          \
1452         init_waitqueue_head(&sk->sk_lock.wq);                           \
1453         spin_lock_init(&(sk)->sk_lock.slock);                           \
1454         debug_check_no_locks_freed((void *)&(sk)->sk_lock,              \
1455                         sizeof((sk)->sk_lock));                         \
1456         lockdep_set_class_and_name(&(sk)->sk_lock.slock,                \
1457                                 (skey), (sname));                               \
1458         lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);     \
1459 } while (0)
1460 
1461 void lock_sock_nested(struct sock *sk, int subclass);
1462 
1463 static inline void lock_sock(struct sock *sk)
1464 {
1465         lock_sock_nested(sk, 0);
1466 }
1467 
1468 void release_sock(struct sock *sk);
1469 
1470 /* BH context may only use the following locking interface. */
1471 #define bh_lock_sock(__sk)      spin_lock(&((__sk)->sk_lock.slock))
1472 #define bh_lock_sock_nested(__sk) \
1473                                 spin_lock_nested(&((__sk)->sk_lock.slock), \
1474                                 SINGLE_DEPTH_NESTING)
1475 #define bh_unlock_sock(__sk)    spin_unlock(&((__sk)->sk_lock.slock))
1476 
1477 bool lock_sock_fast(struct sock *sk);
1478 /**
1479  * unlock_sock_fast - complement of lock_sock_fast
1480  * @sk: socket
1481  * @slow: slow mode
1482  *
1483  * fast unlock socket for user context.
1484  * If slow mode is on, we call regular release_sock()
1485  */
1486 static inline void unlock_sock_fast(struct sock *sk, bool slow)
1487 {
1488         if (slow)
1489                 release_sock(sk);
1490         else
1491                 spin_unlock_bh(&sk->sk_lock.slock);
1492 }
1493 
1494 
1495 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
1496                       struct proto *prot, int kern);
1497 void sk_free(struct sock *sk);
1498 void sk_destruct(struct sock *sk);
1499 struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority);
1500 
1501 struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
1502                              gfp_t priority);
1503 void sock_wfree(struct sk_buff *skb);
1504 void skb_orphan_partial(struct sk_buff *skb);
1505 void sock_rfree(struct sk_buff *skb);
1506 void sock_efree(struct sk_buff *skb);
1507 #ifdef CONFIG_INET
1508 void sock_edemux(struct sk_buff *skb);
1509 #else
1510 #define sock_edemux(skb) sock_efree(skb)
1511 #endif
1512 
1513 int sock_setsockopt(struct socket *sock, int level, int op,
1514                     char __user *optval, unsigned int optlen);
1515 
1516 int sock_getsockopt(struct socket *sock, int level, int op,
1517                     char __user *optval, int __user *optlen);
1518 struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size,
1519                                     int noblock, int *errcode);
1520 struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
1521                                      unsigned long data_len, int noblock,
1522                                      int *errcode, int max_page_order);
1523 void *sock_kmalloc(struct sock *sk, int size, gfp_t priority);
1524 void sock_kfree_s(struct sock *sk, void *mem, int size);
1525 void sock_kzfree_s(struct sock *sk, void *mem, int size);
1526 void sk_send_sigurg(struct sock *sk);
1527 
1528 /*
1529  * Functions to fill in entries in struct proto_ops when a protocol
1530  * does not implement a particular function.
1531  */
1532 int sock_no_bind(struct socket *, struct sockaddr *, int);
1533 int sock_no_connect(struct socket *, struct sockaddr *, int, int);
1534 int sock_no_socketpair(struct socket *, struct socket *);
1535 int sock_no_accept(struct socket *, struct socket *, int);
1536 int sock_no_getname(struct socket *, struct sockaddr *, int *, int);
1537 unsigned int sock_no_poll(struct file *, struct socket *,
1538                           struct poll_table_struct *);
1539 int sock_no_ioctl(struct socket *, unsigned int, unsigned long);
1540 int sock_no_listen(struct socket *, int);
1541 int sock_no_shutdown(struct socket *, int);
1542 int sock_no_getsockopt(struct socket *, int , int, char __user *, int __user *);
1543 int sock_no_setsockopt(struct socket *, int, int, char __user *, unsigned int);
1544 int sock_no_sendmsg(struct socket *, struct msghdr *, size_t);
1545 int sock_no_recvmsg(struct socket *, struct msghdr *, size_t, int);
1546 int sock_no_mmap(struct file *file, struct socket *sock,
1547                  struct vm_area_struct *vma);
1548 ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset,
1549                          size_t size, int flags);
1550 
1551 /*
1552  * Functions to fill in entries in struct proto_ops when a protocol
1553  * uses the inet style.
1554  */
1555 int sock_common_getsockopt(struct socket *sock, int level, int optname,
1556                                   char __user *optval, int __user *optlen);
1557 int sock_common_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1558                         int flags);
1559 int sock_common_setsockopt(struct socket *sock, int level, int optname,
1560                                   char __user *optval, unsigned int optlen);
1561 int compat_sock_common_getsockopt(struct socket *sock, int level,
1562                 int optname, char __user *optval, int __user *optlen);
1563 int compat_sock_common_setsockopt(struct socket *sock, int level,
1564                 int optname, char __user *optval, unsigned int optlen);
1565 
1566 void sk_common_release(struct sock *sk);
1567 
1568 /*
1569  *      Default socket callbacks and setup code
1570  */
1571 
1572 /* Initialise core socket variables */
1573 void sock_init_data(struct socket *sock, struct sock *sk);
1574 
1575 /*
1576  * Socket reference counting postulates.
1577  *
1578  * * Each user of socket SHOULD hold a reference count.
1579  * * Each access point to socket (an hash table bucket, reference from a list,
1580  *   running timer, skb in flight MUST hold a reference count.
1581  * * When reference count hits 0, it means it will never increase back.
1582  * * When reference count hits 0, it means that no references from
1583  *   outside exist to this socket and current process on current CPU
1584  *   is last user and may/should destroy this socket.
1585  * * sk_free is called from any context: process, BH, IRQ. When
1586  *   it is called, socket has no references from outside -> sk_free
1587  *   may release descendant resources allocated by the socket, but
1588  *   to the time when it is called, socket is NOT referenced by any
1589  *   hash tables, lists etc.
1590  * * Packets, delivered from outside (from network or from another process)
1591  *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1592  *   when they sit in queue. Otherwise, packets will leak to hole, when
1593  *   socket is looked up by one cpu and unhasing is made by another CPU.
1594  *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1595  *   (leak to backlog). Packet socket does all the processing inside
1596  *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1597  *   use separate SMP lock, so that they are prone too.
1598  */
1599 
1600 /* Ungrab socket and destroy it, if it was the last reference. */
1601 static inline void sock_put(struct sock *sk)
1602 {
1603         if (atomic_dec_and_test(&sk->sk_refcnt))
1604                 sk_free(sk);
1605 }
1606 /* Generic version of sock_put(), dealing with all sockets
1607  * (TCP_TIMEWAIT, TCP_NEW_SYN_RECV, ESTABLISHED...)
1608  */
1609 void sock_gen_put(struct sock *sk);
1610 
1611 int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested);
1612 
1613 static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
1614 {
1615         sk->sk_tx_queue_mapping = tx_queue;
1616 }
1617 
1618 static inline void sk_tx_queue_clear(struct sock *sk)
1619 {
1620         sk->sk_tx_queue_mapping = -1;
1621 }
1622 
1623 static inline int sk_tx_queue_get(const struct sock *sk)
1624 {
1625         return sk ? sk->sk_tx_queue_mapping : -1;
1626 }
1627 
1628 static inline void sk_set_socket(struct sock *sk, struct socket *sock)
1629 {
1630         sk_tx_queue_clear(sk);
1631         sk->sk_socket = sock;
1632 }
1633 
1634 static inline wait_queue_head_t *sk_sleep(struct sock *sk)
1635 {
1636         BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
1637         return &rcu_dereference_raw(sk->sk_wq)->wait;
1638 }
1639 /* Detach socket from process context.
1640  * Announce socket dead, detach it from wait queue and inode.
1641  * Note that parent inode held reference count on this struct sock,
1642  * we do not release it in this function, because protocol
1643  * probably wants some additional cleanups or even continuing
1644  * to work with this socket (TCP).
1645  */
1646 static inline void sock_orphan(struct sock *sk)
1647 {
1648         write_lock_bh(&sk->sk_callback_lock);
1649         sock_set_flag(sk, SOCK_DEAD);
1650         sk_set_socket(sk, NULL);
1651         sk->sk_wq  = NULL;
1652         write_unlock_bh(&sk->sk_callback_lock);
1653 }
1654 
1655 static inline void sock_graft(struct sock *sk, struct socket *parent)
1656 {
1657         write_lock_bh(&sk->sk_callback_lock);
1658         sk->sk_wq = parent->wq;
1659         parent->sk = sk;
1660         sk_set_socket(sk, parent);
1661         security_sock_graft(sk, parent);
1662         write_unlock_bh(&sk->sk_callback_lock);
1663 }
1664 
1665 kuid_t sock_i_uid(struct sock *sk);
1666 unsigned long sock_i_ino(struct sock *sk);
1667 
1668 static inline void sk_set_txhash(struct sock *sk)
1669 {
1670         sk->sk_txhash = prandom_u32();
1671 
1672         if (unlikely(!sk->sk_txhash))
1673                 sk->sk_txhash = 1;
1674 }
1675 
1676 static inline void sk_rethink_txhash(struct sock *sk)
1677 {
1678         if (sk->sk_txhash)
1679                 sk_set_txhash(sk);
1680 }
1681 
1682 static inline struct dst_entry *
1683 __sk_dst_get(struct sock *sk)
1684 {
1685         return rcu_dereference_check(sk->sk_dst_cache, sock_owned_by_user(sk) ||
1686                                                        lockdep_is_held(&sk->sk_lock.slock));
1687 }
1688 
1689 static inline struct dst_entry *
1690 sk_dst_get(struct sock *sk)
1691 {
1692         struct dst_entry *dst;
1693 
1694         rcu_read_lock();
1695         dst = rcu_dereference(sk->sk_dst_cache);
1696         if (dst && !atomic_inc_not_zero(&dst->__refcnt))
1697                 dst = NULL;
1698         rcu_read_unlock();
1699         return dst;
1700 }
1701 
1702 static inline void dst_negative_advice(struct sock *sk)
1703 {
1704         struct dst_entry *ndst, *dst = __sk_dst_get(sk);
1705 
1706         sk_rethink_txhash(sk);
1707 
1708         if (dst && dst->ops->negative_advice) {
1709                 ndst = dst->ops->negative_advice(dst);
1710 
1711                 if (ndst != dst) {
1712                         rcu_assign_pointer(sk->sk_dst_cache, ndst);
1713                         sk_tx_queue_clear(sk);
1714                 }
1715         }
1716 }
1717 
1718 static inline void
1719 __sk_dst_set(struct sock *sk, struct dst_entry *dst)
1720 {
1721         struct dst_entry *old_dst;
1722 
1723         sk_tx_queue_clear(sk);
1724         /*
1725          * This can be called while sk is owned by the caller only,
1726          * with no state that can be checked in a rcu_dereference_check() cond
1727          */
1728         old_dst = rcu_dereference_raw(sk->sk_dst_cache);
1729         rcu_assign_pointer(sk->sk_dst_cache, dst);
1730         dst_release(old_dst);
1731 }
1732 
1733 static inline void
1734 sk_dst_set(struct sock *sk, struct dst_entry *dst)
1735 {
1736         struct dst_entry *old_dst;
1737 
1738         sk_tx_queue_clear(sk);
1739         old_dst = xchg((__force struct dst_entry **)&sk->sk_dst_cache, dst);
1740         dst_release(old_dst);
1741 }
1742 
1743 static inline void
1744 __sk_dst_reset(struct sock *sk)
1745 {
1746         __sk_dst_set(sk, NULL);
1747 }
1748 
1749 static inline void
1750 sk_dst_reset(struct sock *sk)
1751 {
1752         sk_dst_set(sk, NULL);
1753 }
1754 
1755 struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
1756 
1757 struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
1758 
1759 bool sk_mc_loop(struct sock *sk);
1760 
1761 static inline bool sk_can_gso(const struct sock *sk)
1762 {
1763         return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
1764 }
1765 
1766 void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
1767 
1768 static inline void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
1769 {
1770         sk->sk_route_nocaps |= flags;
1771         sk->sk_route_caps &= ~flags;
1772 }
1773 
1774 static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
1775                                            struct iov_iter *from, char *to,
1776                                            int copy, int offset)
1777 {
1778         if (skb->ip_summed == CHECKSUM_NONE) {
1779                 __wsum csum = 0;
1780                 if (csum_and_copy_from_iter(to, copy, &csum, from) != copy)
1781                         return -EFAULT;
1782                 skb->csum = csum_block_add(skb->csum, csum, offset);
1783         } else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1784                 if (copy_from_iter_nocache(to, copy, from) != copy)
1785                         return -EFAULT;
1786         } else if (copy_from_iter(to, copy, from) != copy)
1787                 return -EFAULT;
1788 
1789         return 0;
1790 }
1791 
1792 static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
1793                                        struct iov_iter *from, int copy)
1794 {
1795         int err, offset = skb->len;
1796 
1797         err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
1798                                        copy, offset);
1799         if (err)
1800                 __skb_trim(skb, offset);
1801 
1802         return err;
1803 }
1804 
1805 static inline int skb_copy_to_page_nocache(struct sock *sk, struct iov_iter *from,
1806                                            struct sk_buff *skb,
1807                                            struct page *page,
1808                                            int off, int copy)
1809 {
1810         int err;
1811 
1812         err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
1813                                        copy, skb->len);
1814         if (err)
1815                 return err;
1816 
1817         skb->len             += copy;
1818         skb->data_len        += copy;
1819         skb->truesize        += copy;
1820         sk->sk_wmem_queued   += copy;
1821         sk_mem_charge(sk, copy);
1822         return 0;
1823 }
1824 
1825 /**
1826  * sk_wmem_alloc_get - returns write allocations
1827  * @sk: socket
1828  *
1829  * Returns sk_wmem_alloc minus initial offset of one
1830  */
1831 static inline int sk_wmem_alloc_get(const struct sock *sk)
1832 {
1833         return atomic_read(&sk->sk_wmem_alloc) - 1;
1834 }
1835 
1836 /**
1837  * sk_rmem_alloc_get - returns read allocations
1838  * @sk: socket
1839  *
1840  * Returns sk_rmem_alloc
1841  */
1842 static inline int sk_rmem_alloc_get(const struct sock *sk)
1843 {
1844         return atomic_read(&sk->sk_rmem_alloc);
1845 }
1846 
1847 /**
1848  * sk_has_allocations - check if allocations are outstanding
1849  * @sk: socket
1850  *
1851  * Returns true if socket has write or read allocations
1852  */
1853 static inline bool sk_has_allocations(const struct sock *sk)
1854 {
1855         return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
1856 }
1857 
1858 /**
1859  * wq_has_sleeper - check if there are any waiting processes
1860  * @wq: struct socket_wq
1861  *
1862  * Returns true if socket_wq has waiting processes
1863  *
1864  * The purpose of the wq_has_sleeper and sock_poll_wait is to wrap the memory
1865  * barrier call. They were added due to the race found within the tcp code.
1866  *
1867  * Consider following tcp code paths:
1868  *
1869  * CPU1                  CPU2
1870  *
1871  * sys_select            receive packet
1872  *   ...                 ...
1873  *   __add_wait_queue    update tp->rcv_nxt
1874  *   ...                 ...
1875  *   tp->rcv_nxt check   sock_def_readable
1876  *   ...                 {
1877  *   schedule               rcu_read_lock();
1878  *                          wq = rcu_dereference(sk->sk_wq);
1879  *                          if (wq && waitqueue_active(&wq->wait))
1880  *                              wake_up_interruptible(&wq->wait)
1881  *                          ...
1882  *                       }
1883  *
1884  * The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
1885  * in its cache, and so does the tp->rcv_nxt update on CPU2 side.  The CPU1
1886  * could then endup calling schedule and sleep forever if there are no more
1887  * data on the socket.
1888  *
1889  */
1890 static inline bool wq_has_sleeper(struct socket_wq *wq)
1891 {
1892         /* We need to be sure we are in sync with the
1893          * add_wait_queue modifications to the wait queue.
1894          *
1895          * This memory barrier is paired in the sock_poll_wait.
1896          */
1897         smp_mb();
1898         return wq && waitqueue_active(&wq->wait);
1899 }
1900 
1901 /**
1902  * sock_poll_wait - place memory barrier behind the poll_wait call.
1903  * @filp:           file
1904  * @wait_address:   socket wait queue
1905  * @p:              poll_table
1906  *
1907  * See the comments in the wq_has_sleeper function.
1908  */
1909 static inline void sock_poll_wait(struct file *filp,
1910                 wait_queue_head_t *wait_address, poll_table *p)
1911 {
1912         if (!poll_does_not_wait(p) && wait_address) {
1913                 poll_wait(filp, wait_address, p);
1914                 /* We need to be sure we are in sync with the
1915                  * socket flags modification.
1916                  *
1917                  * This memory barrier is paired in the wq_has_sleeper.
1918                  */
1919                 smp_mb();
1920         }
1921 }
1922 
1923 static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)
1924 {
1925         if (sk->sk_txhash) {
1926                 skb->l4_hash = 1;
1927                 skb->hash = sk->sk_txhash;
1928         }
1929 }
1930 
1931 /*
1932  *      Queue a received datagram if it will fit. Stream and sequenced
1933  *      protocols can't normally use this as they need to fit buffers in
1934  *      and play with them.
1935  *
1936  *      Inlined as it's very short and called for pretty much every
1937  *      packet ever received.
1938  */
1939 
1940 static inline void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1941 {
1942         skb_orphan(skb);
1943         skb->sk = sk;
1944         skb->destructor = sock_wfree;
1945         skb_set_hash_from_sk(skb, sk);
1946         /*
1947          * We used to take a refcount on sk, but following operation
1948          * is enough to guarantee sk_free() wont free this sock until
1949          * all in-flight packets are completed
1950          */
1951         atomic_add(skb->truesize, &sk->sk_wmem_alloc);
1952 }
1953 
1954 static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
1955 {
1956         skb_orphan(skb);
1957         skb->sk = sk;
1958         skb->destructor = sock_rfree;
1959         atomic_add(skb->truesize, &sk->sk_rmem_alloc);
1960         sk_mem_charge(sk, skb->truesize);
1961 }
1962 
1963 void sk_reset_timer(struct sock *sk, struct timer_list *timer,
1964                     unsigned long expires);
1965 
1966 void sk_stop_timer(struct sock *sk, struct timer_list *timer);
1967 
1968 int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
1969 
1970 int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
1971 struct sk_buff *sock_dequeue_err_skb(struct sock *sk);
1972 
1973 /*
1974  *      Recover an error report and clear atomically
1975  */
1976 
1977 static inline int sock_error(struct sock *sk)
1978 {
1979         int err;
1980         if (likely(!sk->sk_err))
1981                 return 0;
1982         err = xchg(&sk->sk_err, 0);
1983         return -err;
1984 }
1985 
1986 static inline unsigned long sock_wspace(struct sock *sk)
1987 {
1988         int amt = 0;
1989 
1990         if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
1991                 amt = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
1992                 if (amt < 0)
1993                         amt = 0;
1994         }
1995         return amt;
1996 }
1997 
1998 static inline void sk_wake_async(struct sock *sk, int how, int band)
1999 {
2000         if (sock_flag(sk, SOCK_FASYNC))
2001                 sock_wake_async(sk->sk_socket, how, band);
2002 }
2003 
2004 /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might
2005  * need sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak.
2006  * Note: for send buffers, TCP works better if we can build two skbs at
2007  * minimum.
2008  */
2009 #define TCP_SKB_MIN_TRUESIZE    (2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
2010 
2011 #define SOCK_MIN_SNDBUF         (TCP_SKB_MIN_TRUESIZE * 2)
2012 #define SOCK_MIN_RCVBUF          TCP_SKB_MIN_TRUESIZE
2013 
2014 static inline void sk_stream_moderate_sndbuf(struct sock *sk)
2015 {
2016         if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
2017                 sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
2018                 sk->sk_sndbuf = max_t(u32, sk->sk_sndbuf, SOCK_MIN_SNDBUF);
2019         }
2020 }
2021 
2022 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
2023                                     bool force_schedule);
2024 
2025 /**
2026  * sk_page_frag - return an appropriate page_frag
2027  * @sk: socket
2028  *
2029  * If socket allocation mode allows current thread to sleep, it means its
2030  * safe to use the per task page_frag instead of the per socket one.
2031  */
2032 static inline struct page_frag *sk_page_frag(struct sock *sk)
2033 {
2034         if (sk->sk_allocation & __GFP_WAIT)
2035                 return &current->task_frag;
2036 
2037         return &sk->sk_frag;
2038 }
2039 
2040 bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag);
2041 
2042 /*
2043  *      Default write policy as shown to user space via poll/select/SIGIO
2044  */
2045 static inline bool sock_writeable(const struct sock *sk)
2046 {
2047         return atomic_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
2048 }
2049 
2050 static inline gfp_t gfp_any(void)
2051 {
2052         return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
2053 }
2054 
2055 static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
2056 {
2057         return noblock ? 0 : sk->sk_rcvtimeo;
2058 }
2059 
2060 static inline long sock_sndtimeo(const struct sock *sk, bool noblock)
2061 {
2062         return noblock ? 0 : sk->sk_sndtimeo;
2063 }
2064 
2065 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
2066 {
2067         return (waitall ? len : min_t(int, sk->sk_rcvlowat, len)) ? : 1;
2068 }
2069 
2070 /* Alas, with timeout socket operations are not restartable.
2071  * Compare this to poll().
2072  */
2073 static inline int sock_intr_errno(long timeo)
2074 {
2075         return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
2076 }
2077 
2078 struct sock_skb_cb {
2079         u32 dropcount;
2080 };
2081 
2082 /* Store sock_skb_cb at the end of skb->cb[] so protocol families
2083  * using skb->cb[] would keep using it directly and utilize its
2084  * alignement guarantee.
2085  */
2086 #define SOCK_SKB_CB_OFFSET ((FIELD_SIZEOF(struct sk_buff, cb) - \
2087                             sizeof(struct sock_skb_cb)))
2088 
2089 #define SOCK_SKB_CB(__skb) ((struct sock_skb_cb *)((__skb)->cb + \
2090                             SOCK_SKB_CB_OFFSET))
2091 
2092 #define sock_skb_cb_check_size(size) \
2093         BUILD_BUG_ON((size) > SOCK_SKB_CB_OFFSET)
2094 
2095 static inline void
2096 sock_skb_set_dropcount(const struct sock *sk, struct sk_buff *skb)
2097 {
2098         SOCK_SKB_CB(skb)->dropcount = atomic_read(&sk->sk_drops);
2099 }
2100 
2101 void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
2102                            struct sk_buff *skb);
2103 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
2104                              struct sk_buff *skb);
2105 
2106 static inline void
2107 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
2108 {
2109         ktime_t kt = skb->tstamp;
2110         struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
2111 
2112         /*
2113          * generate control messages if
2114          * - receive time stamping in software requested
2115          * - software time stamp available and wanted
2116          * - hardware time stamps available and wanted
2117          */
2118         if (sock_flag(sk, SOCK_RCVTSTAMP) ||
2119             (sk->sk_tsflags & SOF_TIMESTAMPING_RX_SOFTWARE) ||
2120             (kt.tv64 && sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) ||
2121             (hwtstamps->hwtstamp.tv64 &&
2122              (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
2123                 __sock_recv_timestamp(msg, sk, skb);
2124         else
2125                 sk->sk_stamp = kt;
2126 
2127         if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
2128                 __sock_recv_wifi_status(msg, sk, skb);
2129 }
2130 
2131 void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2132                               struct sk_buff *skb);
2133 
2134 static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2135                                           struct sk_buff *skb)
2136 {
2137 #define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)                       | \
2138                            (1UL << SOCK_RCVTSTAMP))
2139 #define TSFLAGS_ANY       (SOF_TIMESTAMPING_SOFTWARE                    | \
2140                            SOF_TIMESTAMPING_RAW_HARDWARE)
2141 
2142         if (sk->sk_flags & FLAGS_TS_OR_DROPS || sk->sk_tsflags & TSFLAGS_ANY)
2143                 __sock_recv_ts_and_drops(msg, sk, skb);
2144         else
2145                 sk->sk_stamp = skb->tstamp;
2146 }
2147 
2148 void __sock_tx_timestamp(const struct sock *sk, __u8 *tx_flags);
2149 
2150 /**
2151  * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
2152  * @sk:         socket sending this packet
2153  * @tx_flags:   completed with instructions for time stamping
2154  *
2155  * Note : callers should take care of initial *tx_flags value (usually 0)
2156  */
2157 static inline void sock_tx_timestamp(const struct sock *sk, __u8 *tx_flags)
2158 {
2159         if (unlikely(sk->sk_tsflags))
2160                 __sock_tx_timestamp(sk, tx_flags);
2161         if (unlikely(sock_flag(sk, SOCK_WIFI_STATUS)))
2162                 *tx_flags |= SKBTX_WIFI_STATUS;
2163 }
2164 
2165 /**
2166  * sk_eat_skb - Release a skb if it is no longer needed
2167  * @sk: socket to eat this skb from
2168  * @skb: socket buffer to eat
2169  *
2170  * This routine must be called with interrupts disabled or with the socket
2171  * locked so that the sk_buff queue operation is ok.
2172 */
2173 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb)
2174 {
2175         __skb_unlink(skb, &sk->sk_receive_queue);
2176         __kfree_skb(skb);
2177 }
2178 
2179 static inline
2180 struct net *sock_net(const struct sock *sk)
2181 {
2182         return read_pnet(&sk->sk_net);
2183 }
2184 
2185 static inline
2186 void sock_net_set(struct sock *sk, struct net *net)
2187 {
2188         write_pnet(&sk->sk_net, net);
2189 }
2190 
2191 static inline struct sock *skb_steal_sock(struct sk_buff *skb)
2192 {
2193         if (skb->sk) {
2194                 struct sock *sk = skb->sk;
2195 
2196                 skb->destructor = NULL;
2197                 skb->sk = NULL;
2198                 return sk;
2199         }
2200         return NULL;
2201 }
2202 
2203 /* This helper checks if a socket is a full socket,
2204  * ie _not_ a timewait or request socket.
2205  */
2206 static inline bool sk_fullsock(const struct sock *sk)
2207 {
2208         return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
2209 }
2210 
2211 void sock_enable_timestamp(struct sock *sk, int flag);
2212 int sock_get_timestamp(struct sock *, struct timeval __user *);
2213 int sock_get_timestampns(struct sock *, struct timespec __user *);
2214 int sock_recv_errqueue(struct sock *sk, struct msghdr *msg, int len, int level,
2215                        int type);
2216 
2217 bool sk_ns_capable(const struct sock *sk,
2218                    struct user_namespace *user_ns, int cap);
2219 bool sk_capable(const struct sock *sk, int cap);
2220 bool sk_net_capable(const struct sock *sk, int cap);
2221 
2222 extern __u32 sysctl_wmem_max;
2223 extern __u32 sysctl_rmem_max;
2224 
2225 extern int sysctl_tstamp_allow_data;
2226 extern int sysctl_optmem_max;
2227 
2228 extern __u32 sysctl_wmem_default;
2229 extern __u32 sysctl_rmem_default;
2230 
2231 #endif  /* _SOCK_H */
2232 

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