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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/kernel.h>
 44 #include <linux/list.h>
 45 #include <linux/list_nulls.h>
 46 #include <linux/timer.h>
 47 #include <linux/cache.h>
 48 #include <linux/module.h>
 49 #include <linux/lockdep.h>
 50 #include <linux/netdevice.h>
 51 #include <linux/skbuff.h>       /* struct sk_buff */
 52 #include <linux/mm.h>
 53 #include <linux/security.h>
 54 
 55 #include <linux/filter.h>
 56 #include <linux/rculist_nulls.h>
 57 #include <linux/poll.h>
 58 
 59 #include <asm/atomic.h>
 60 #include <net/dst.h>
 61 #include <net/checksum.h>
 62 
 63 /*
 64  * This structure really needs to be cleaned up.
 65  * Most of it is for TCP, and not used by any of
 66  * the other protocols.
 67  */
 68 
 69 /* Define this to get the SOCK_DBG debugging facility. */
 70 #define SOCK_DEBUGGING
 71 #ifdef SOCK_DEBUGGING
 72 #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
 73                                         printk(KERN_DEBUG msg); } while (0)
 74 #else
 75 /* Validate arguments and do nothing */
 76 static void inline int __attribute__ ((format (printf, 2, 3)))
 77 SOCK_DEBUG(struct sock *sk, const char *msg, ...)
 78 {
 79 }
 80 #endif
 81 
 82 /* This is the per-socket lock.  The spinlock provides a synchronization
 83  * between user contexts and software interrupt processing, whereas the
 84  * mini-semaphore synchronizes multiple users amongst themselves.
 85  */
 86 typedef struct {
 87         spinlock_t              slock;
 88         int                     owned;
 89         wait_queue_head_t       wq;
 90         /*
 91          * We express the mutex-alike socket_lock semantics
 92          * to the lock validator by explicitly managing
 93          * the slock as a lock variant (in addition to
 94          * the slock itself):
 95          */
 96 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 97         struct lockdep_map dep_map;
 98 #endif
 99 } socket_lock_t;
100 
101 struct sock;
102 struct proto;
103 struct net;
104 
105 /**
106  *      struct sock_common - minimal network layer representation of sockets
107  *      @skc_node: main hash linkage for various protocol lookup tables
108  *      @skc_nulls_node: main hash linkage for UDP/UDP-Lite protocol
109  *      @skc_refcnt: reference count
110  *      @skc_hash: hash value used with various protocol lookup tables
111  *      @skc_family: network address family
112  *      @skc_state: Connection state
113  *      @skc_reuse: %SO_REUSEADDR setting
114  *      @skc_bound_dev_if: bound device index if != 0
115  *      @skc_bind_node: bind hash linkage for various protocol lookup tables
116  *      @skc_prot: protocol handlers inside a network family
117  *      @skc_net: reference to the network namespace of this socket
118  *
119  *      This is the minimal network layer representation of sockets, the header
120  *      for struct sock and struct inet_timewait_sock.
121  */
122 struct sock_common {
123         /*
124          * first fields are not copied in sock_copy()
125          */
126         union {
127                 struct hlist_node       skc_node;
128                 struct hlist_nulls_node skc_nulls_node;
129         };
130         atomic_t                skc_refcnt;
131 
132         unsigned int            skc_hash;
133         unsigned short          skc_family;
134         volatile unsigned char  skc_state;
135         unsigned char           skc_reuse;
136         int                     skc_bound_dev_if;
137         struct hlist_node       skc_bind_node;
138         struct proto            *skc_prot;
139 #ifdef CONFIG_NET_NS
140         struct net              *skc_net;
141 #endif
142 };
143 
144 /**
145   *     struct sock - network layer representation of sockets
146   *     @__sk_common: shared layout with inet_timewait_sock
147   *     @sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
148   *     @sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
149   *     @sk_lock:       synchronizer
150   *     @sk_rcvbuf: size of receive buffer in bytes
151   *     @sk_sleep: sock wait queue
152   *     @sk_dst_cache: destination cache
153   *     @sk_dst_lock: destination cache lock
154   *     @sk_policy: flow policy
155   *     @sk_rmem_alloc: receive queue bytes committed
156   *     @sk_receive_queue: incoming packets
157   *     @sk_wmem_alloc: transmit queue bytes committed
158   *     @sk_write_queue: Packet sending queue
159   *     @sk_async_wait_queue: DMA copied packets
160   *     @sk_omem_alloc: "o" is "option" or "other"
161   *     @sk_wmem_queued: persistent queue size
162   *     @sk_forward_alloc: space allocated forward
163   *     @sk_allocation: allocation mode
164   *     @sk_sndbuf: size of send buffer in bytes
165   *     @sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
166   *                %SO_OOBINLINE settings, %SO_TIMESTAMPING settings
167   *     @sk_no_check: %SO_NO_CHECK setting, wether or not checkup packets
168   *     @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
169   *     @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
170   *     @sk_gso_max_size: Maximum GSO segment size to build
171   *     @sk_lingertime: %SO_LINGER l_linger setting
172   *     @sk_backlog: always used with the per-socket spinlock held
173   *     @sk_callback_lock: used with the callbacks in the end of this struct
174   *     @sk_error_queue: rarely used
175   *     @sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
176   *                       IPV6_ADDRFORM for instance)
177   *     @sk_err: last error
178   *     @sk_err_soft: errors that don't cause failure but are the cause of a
179   *                   persistent failure not just 'timed out'
180   *     @sk_drops: raw/udp drops counter
181   *     @sk_ack_backlog: current listen backlog
182   *     @sk_max_ack_backlog: listen backlog set in listen()
183   *     @sk_priority: %SO_PRIORITY setting
184   *     @sk_type: socket type (%SOCK_STREAM, etc)
185   *     @sk_protocol: which protocol this socket belongs in this network family
186   *     @sk_peercred: %SO_PEERCRED setting
187   *     @sk_rcvlowat: %SO_RCVLOWAT setting
188   *     @sk_rcvtimeo: %SO_RCVTIMEO setting
189   *     @sk_sndtimeo: %SO_SNDTIMEO setting
190   *     @sk_filter: socket filtering instructions
191   *     @sk_protinfo: private area, net family specific, when not using slab
192   *     @sk_timer: sock cleanup timer
193   *     @sk_stamp: time stamp of last packet received
194   *     @sk_socket: Identd and reporting IO signals
195   *     @sk_user_data: RPC layer private data
196   *     @sk_sndmsg_page: cached page for sendmsg
197   *     @sk_sndmsg_off: cached offset for sendmsg
198   *     @sk_send_head: front of stuff to transmit
199   *     @sk_security: used by security modules
200   *     @sk_mark: generic packet mark
201   *     @sk_write_pending: a write to stream socket waits to start
202   *     @sk_state_change: callback to indicate change in the state of the sock
203   *     @sk_data_ready: callback to indicate there is data to be processed
204   *     @sk_write_space: callback to indicate there is bf sending space available
205   *     @sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
206   *     @sk_backlog_rcv: callback to process the backlog
207   *     @sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
208  */
209 struct sock {
210         /*
211          * Now struct inet_timewait_sock also uses sock_common, so please just
212          * don't add nothing before this first member (__sk_common) --acme
213          */
214         struct sock_common      __sk_common;
215 #define sk_node                 __sk_common.skc_node
216 #define sk_nulls_node           __sk_common.skc_nulls_node
217 #define sk_refcnt               __sk_common.skc_refcnt
218 
219 #define sk_copy_start           __sk_common.skc_hash
220 #define sk_hash                 __sk_common.skc_hash
221 #define sk_family               __sk_common.skc_family
222 #define sk_state                __sk_common.skc_state
223 #define sk_reuse                __sk_common.skc_reuse
224 #define sk_bound_dev_if         __sk_common.skc_bound_dev_if
225 #define sk_bind_node            __sk_common.skc_bind_node
226 #define sk_prot                 __sk_common.skc_prot
227 #define sk_net                  __sk_common.skc_net
228         kmemcheck_bitfield_begin(flags);
229         unsigned int            sk_shutdown  : 2,
230                                 sk_no_check  : 2,
231                                 sk_userlocks : 4,
232                                 sk_protocol  : 8,
233                                 sk_type      : 16;
234 #define SK_PROTOCOL_MAX ((u8)~0U)
235         kmemcheck_bitfield_end(flags);
236         int                     sk_rcvbuf;
237         socket_lock_t           sk_lock;
238         /*
239          * The backlog queue is special, it is always used with
240          * the per-socket spinlock held and requires low latency
241          * access. Therefore we special case it's implementation.
242          */
243         struct {
244                 struct sk_buff *head;
245                 struct sk_buff *tail;
246         } sk_backlog;
247         wait_queue_head_t       *sk_sleep;
248         struct dst_entry        *sk_dst_cache;
249 #ifdef CONFIG_XFRM
250         struct xfrm_policy      *sk_policy[2];
251 #endif
252         rwlock_t                sk_dst_lock;
253         atomic_t                sk_rmem_alloc;
254         atomic_t                sk_wmem_alloc;
255         atomic_t                sk_omem_alloc;
256         int                     sk_sndbuf;
257         struct sk_buff_head     sk_receive_queue;
258         struct sk_buff_head     sk_write_queue;
259 #ifdef CONFIG_NET_DMA
260         struct sk_buff_head     sk_async_wait_queue;
261 #endif
262         int                     sk_wmem_queued;
263         int                     sk_forward_alloc;
264         gfp_t                   sk_allocation;
265         int                     sk_route_caps;
266         int                     sk_gso_type;
267         unsigned int            sk_gso_max_size;
268         int                     sk_rcvlowat;
269         unsigned long           sk_flags;
270         unsigned long           sk_lingertime;
271         struct sk_buff_head     sk_error_queue;
272         struct proto            *sk_prot_creator;
273         rwlock_t                sk_callback_lock;
274         int                     sk_err,
275                                 sk_err_soft;
276         atomic_t                sk_drops;
277         unsigned short          sk_ack_backlog;
278         unsigned short          sk_max_ack_backlog;
279         __u32                   sk_priority;
280         struct ucred            sk_peercred;
281         long                    sk_rcvtimeo;
282         long                    sk_sndtimeo;
283         struct sk_filter        *sk_filter;
284         void                    *sk_protinfo;
285         struct timer_list       sk_timer;
286         ktime_t                 sk_stamp;
287         struct socket           *sk_socket;
288         void                    *sk_user_data;
289         struct page             *sk_sndmsg_page;
290         struct sk_buff          *sk_send_head;
291         __u32                   sk_sndmsg_off;
292         int                     sk_write_pending;
293 #ifdef CONFIG_SECURITY
294         void                    *sk_security;
295 #endif
296         __u32                   sk_mark;
297         /* XXX 4 bytes hole on 64 bit */
298         void                    (*sk_state_change)(struct sock *sk);
299         void                    (*sk_data_ready)(struct sock *sk, int bytes);
300         void                    (*sk_write_space)(struct sock *sk);
301         void                    (*sk_error_report)(struct sock *sk);
302         int                     (*sk_backlog_rcv)(struct sock *sk,
303                                                   struct sk_buff *skb);  
304         void                    (*sk_destruct)(struct sock *sk);
305 };
306 
307 /*
308  * Hashed lists helper routines
309  */
310 static inline struct sock *__sk_head(const struct hlist_head *head)
311 {
312         return hlist_entry(head->first, struct sock, sk_node);
313 }
314 
315 static inline struct sock *sk_head(const struct hlist_head *head)
316 {
317         return hlist_empty(head) ? NULL : __sk_head(head);
318 }
319 
320 static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
321 {
322         return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
323 }
324 
325 static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
326 {
327         return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
328 }
329 
330 static inline struct sock *sk_next(const struct sock *sk)
331 {
332         return sk->sk_node.next ?
333                 hlist_entry(sk->sk_node.next, struct sock, sk_node) : NULL;
334 }
335 
336 static inline struct sock *sk_nulls_next(const struct sock *sk)
337 {
338         return (!is_a_nulls(sk->sk_nulls_node.next)) ?
339                 hlist_nulls_entry(sk->sk_nulls_node.next,
340                                   struct sock, sk_nulls_node) :
341                 NULL;
342 }
343 
344 static inline int sk_unhashed(const struct sock *sk)
345 {
346         return hlist_unhashed(&sk->sk_node);
347 }
348 
349 static inline int sk_hashed(const struct sock *sk)
350 {
351         return !sk_unhashed(sk);
352 }
353 
354 static __inline__ void sk_node_init(struct hlist_node *node)
355 {
356         node->pprev = NULL;
357 }
358 
359 static __inline__ void sk_nulls_node_init(struct hlist_nulls_node *node)
360 {
361         node->pprev = NULL;
362 }
363 
364 static __inline__ void __sk_del_node(struct sock *sk)
365 {
366         __hlist_del(&sk->sk_node);
367 }
368 
369 static __inline__ int __sk_del_node_init(struct sock *sk)
370 {
371         if (sk_hashed(sk)) {
372                 __sk_del_node(sk);
373                 sk_node_init(&sk->sk_node);
374                 return 1;
375         }
376         return 0;
377 }
378 
379 /* Grab socket reference count. This operation is valid only
380    when sk is ALREADY grabbed f.e. it is found in hash table
381    or a list and the lookup is made under lock preventing hash table
382    modifications.
383  */
384 
385 static inline void sock_hold(struct sock *sk)
386 {
387         atomic_inc(&sk->sk_refcnt);
388 }
389 
390 /* Ungrab socket in the context, which assumes that socket refcnt
391    cannot hit zero, f.e. it is true in context of any socketcall.
392  */
393 static inline void __sock_put(struct sock *sk)
394 {
395         atomic_dec(&sk->sk_refcnt);
396 }
397 
398 static __inline__ int sk_del_node_init(struct sock *sk)
399 {
400         int rc = __sk_del_node_init(sk);
401 
402         if (rc) {
403                 /* paranoid for a while -acme */
404                 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
405                 __sock_put(sk);
406         }
407         return rc;
408 }
409 
410 static __inline__ int __sk_nulls_del_node_init_rcu(struct sock *sk)
411 {
412         if (sk_hashed(sk)) {
413                 hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
414                 return 1;
415         }
416         return 0;
417 }
418 
419 static __inline__ int sk_nulls_del_node_init_rcu(struct sock *sk)
420 {
421         int rc = __sk_nulls_del_node_init_rcu(sk);
422 
423         if (rc) {
424                 /* paranoid for a while -acme */
425                 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
426                 __sock_put(sk);
427         }
428         return rc;
429 }
430 
431 static __inline__ void __sk_add_node(struct sock *sk, struct hlist_head *list)
432 {
433         hlist_add_head(&sk->sk_node, list);
434 }
435 
436 static __inline__ void sk_add_node(struct sock *sk, struct hlist_head *list)
437 {
438         sock_hold(sk);
439         __sk_add_node(sk, list);
440 }
441 
442 static __inline__ void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
443 {
444         hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
445 }
446 
447 static __inline__ void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
448 {
449         sock_hold(sk);
450         __sk_nulls_add_node_rcu(sk, list);
451 }
452 
453 static __inline__ void __sk_del_bind_node(struct sock *sk)
454 {
455         __hlist_del(&sk->sk_bind_node);
456 }
457 
458 static __inline__ void sk_add_bind_node(struct sock *sk,
459                                         struct hlist_head *list)
460 {
461         hlist_add_head(&sk->sk_bind_node, list);
462 }
463 
464 #define sk_for_each(__sk, node, list) \
465         hlist_for_each_entry(__sk, node, list, sk_node)
466 #define sk_nulls_for_each(__sk, node, list) \
467         hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
468 #define sk_nulls_for_each_rcu(__sk, node, list) \
469         hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
470 #define sk_for_each_from(__sk, node) \
471         if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
472                 hlist_for_each_entry_from(__sk, node, sk_node)
473 #define sk_nulls_for_each_from(__sk, node) \
474         if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
475                 hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
476 #define sk_for_each_continue(__sk, node) \
477         if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
478                 hlist_for_each_entry_continue(__sk, node, sk_node)
479 #define sk_for_each_safe(__sk, node, tmp, list) \
480         hlist_for_each_entry_safe(__sk, node, tmp, list, sk_node)
481 #define sk_for_each_bound(__sk, node, list) \
482         hlist_for_each_entry(__sk, node, list, sk_bind_node)
483 
484 /* Sock flags */
485 enum sock_flags {
486         SOCK_DEAD,
487         SOCK_DONE,
488         SOCK_URGINLINE,
489         SOCK_KEEPOPEN,
490         SOCK_LINGER,
491         SOCK_DESTROY,
492         SOCK_BROADCAST,
493         SOCK_TIMESTAMP,
494         SOCK_ZAPPED,
495         SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
496         SOCK_DBG, /* %SO_DEBUG setting */
497         SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
498         SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
499         SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
500         SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
501         SOCK_TIMESTAMPING_TX_HARDWARE,  /* %SOF_TIMESTAMPING_TX_HARDWARE */
502         SOCK_TIMESTAMPING_TX_SOFTWARE,  /* %SOF_TIMESTAMPING_TX_SOFTWARE */
503         SOCK_TIMESTAMPING_RX_HARDWARE,  /* %SOF_TIMESTAMPING_RX_HARDWARE */
504         SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
505         SOCK_TIMESTAMPING_SOFTWARE,     /* %SOF_TIMESTAMPING_SOFTWARE */
506         SOCK_TIMESTAMPING_RAW_HARDWARE, /* %SOF_TIMESTAMPING_RAW_HARDWARE */
507         SOCK_TIMESTAMPING_SYS_HARDWARE, /* %SOF_TIMESTAMPING_SYS_HARDWARE */
508 };
509 
510 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
511 
512 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
513 {
514         nsk->sk_flags = osk->sk_flags;
515 }
516 
517 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
518 {
519         __set_bit(flag, &sk->sk_flags);
520 }
521 
522 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
523 {
524         __clear_bit(flag, &sk->sk_flags);
525 }
526 
527 static inline int sock_flag(struct sock *sk, enum sock_flags flag)
528 {
529         return test_bit(flag, &sk->sk_flags);
530 }
531 
532 static inline void sk_acceptq_removed(struct sock *sk)
533 {
534         sk->sk_ack_backlog--;
535 }
536 
537 static inline void sk_acceptq_added(struct sock *sk)
538 {
539         sk->sk_ack_backlog++;
540 }
541 
542 static inline int sk_acceptq_is_full(struct sock *sk)
543 {
544         return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
545 }
546 
547 /*
548  * Compute minimal free write space needed to queue new packets.
549  */
550 static inline int sk_stream_min_wspace(struct sock *sk)
551 {
552         return sk->sk_wmem_queued >> 1;
553 }
554 
555 static inline int sk_stream_wspace(struct sock *sk)
556 {
557         return sk->sk_sndbuf - sk->sk_wmem_queued;
558 }
559 
560 extern void sk_stream_write_space(struct sock *sk);
561 
562 static inline int sk_stream_memory_free(struct sock *sk)
563 {
564         return sk->sk_wmem_queued < sk->sk_sndbuf;
565 }
566 
567 /* The per-socket spinlock must be held here. */
568 static inline void sk_add_backlog(struct sock *sk, struct sk_buff *skb)
569 {
570         if (!sk->sk_backlog.tail) {
571                 sk->sk_backlog.head = sk->sk_backlog.tail = skb;
572         } else {
573                 sk->sk_backlog.tail->next = skb;
574                 sk->sk_backlog.tail = skb;
575         }
576         skb->next = NULL;
577 }
578 
579 static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
580 {
581         return sk->sk_backlog_rcv(sk, skb);
582 }
583 
584 #define sk_wait_event(__sk, __timeo, __condition)                       \
585         ({      int __rc;                                               \
586                 release_sock(__sk);                                     \
587                 __rc = __condition;                                     \
588                 if (!__rc) {                                            \
589                         *(__timeo) = schedule_timeout(*(__timeo));      \
590                 }                                                       \
591                 lock_sock(__sk);                                        \
592                 __rc = __condition;                                     \
593                 __rc;                                                   \
594         })
595 
596 extern int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
597 extern int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
598 extern void sk_stream_wait_close(struct sock *sk, long timeo_p);
599 extern int sk_stream_error(struct sock *sk, int flags, int err);
600 extern void sk_stream_kill_queues(struct sock *sk);
601 
602 extern int sk_wait_data(struct sock *sk, long *timeo);
603 
604 struct request_sock_ops;
605 struct timewait_sock_ops;
606 struct inet_hashinfo;
607 struct raw_hashinfo;
608 
609 /* Networking protocol blocks we attach to sockets.
610  * socket layer -> transport layer interface
611  * transport -> network interface is defined by struct inet_proto
612  */
613 struct proto {
614         void                    (*close)(struct sock *sk, 
615                                         long timeout);
616         int                     (*connect)(struct sock *sk,
617                                         struct sockaddr *uaddr, 
618                                         int addr_len);
619         int                     (*disconnect)(struct sock *sk, int flags);
620 
621         struct sock *           (*accept) (struct sock *sk, int flags, int *err);
622 
623         int                     (*ioctl)(struct sock *sk, int cmd,
624                                          unsigned long arg);
625         int                     (*init)(struct sock *sk);
626         void                    (*destroy)(struct sock *sk);
627         void                    (*shutdown)(struct sock *sk, int how);
628         int                     (*setsockopt)(struct sock *sk, int level, 
629                                         int optname, char __user *optval,
630                                         unsigned int optlen);
631         int                     (*getsockopt)(struct sock *sk, int level, 
632                                         int optname, char __user *optval, 
633                                         int __user *option);     
634 #ifdef CONFIG_COMPAT
635         int                     (*compat_setsockopt)(struct sock *sk,
636                                         int level,
637                                         int optname, char __user *optval,
638                                         unsigned int optlen);
639         int                     (*compat_getsockopt)(struct sock *sk,
640                                         int level,
641                                         int optname, char __user *optval,
642                                         int __user *option);
643 #endif
644         int                     (*sendmsg)(struct kiocb *iocb, struct sock *sk,
645                                            struct msghdr *msg, size_t len);
646         int                     (*recvmsg)(struct kiocb *iocb, struct sock *sk,
647                                            struct msghdr *msg,
648                                         size_t len, int noblock, int flags, 
649                                         int *addr_len);
650         int                     (*sendpage)(struct sock *sk, struct page *page,
651                                         int offset, size_t size, int flags);
652         int                     (*bind)(struct sock *sk, 
653                                         struct sockaddr *uaddr, int addr_len);
654 
655         int                     (*backlog_rcv) (struct sock *sk, 
656                                                 struct sk_buff *skb);
657 
658         /* Keeping track of sk's, looking them up, and port selection methods. */
659         void                    (*hash)(struct sock *sk);
660         void                    (*unhash)(struct sock *sk);
661         int                     (*get_port)(struct sock *sk, unsigned short snum);
662 
663         /* Keeping track of sockets in use */
664 #ifdef CONFIG_PROC_FS
665         unsigned int            inuse_idx;
666 #endif
667 
668         /* Memory pressure */
669         void                    (*enter_memory_pressure)(struct sock *sk);
670         atomic_t                *memory_allocated;      /* Current allocated memory. */
671         struct percpu_counter   *sockets_allocated;     /* Current number of sockets. */
672         /*
673          * Pressure flag: try to collapse.
674          * Technical note: it is used by multiple contexts non atomically.
675          * All the __sk_mem_schedule() is of this nature: accounting
676          * is strict, actions are advisory and have some latency.
677          */
678         int                     *memory_pressure;
679         int                     *sysctl_mem;
680         int                     *sysctl_wmem;
681         int                     *sysctl_rmem;
682         int                     max_header;
683 
684         struct kmem_cache       *slab;
685         unsigned int            obj_size;
686         int                     slab_flags;
687 
688         struct percpu_counter   *orphan_count;
689 
690         struct request_sock_ops *rsk_prot;
691         struct timewait_sock_ops *twsk_prot;
692 
693         union {
694                 struct inet_hashinfo    *hashinfo;
695                 struct udp_table        *udp_table;
696                 struct raw_hashinfo     *raw_hash;
697         } h;
698 
699         struct module           *owner;
700 
701         char                    name[32];
702 
703         struct list_head        node;
704 #ifdef SOCK_REFCNT_DEBUG
705         atomic_t                socks;
706 #endif
707 };
708 
709 extern int proto_register(struct proto *prot, int alloc_slab);
710 extern void proto_unregister(struct proto *prot);
711 
712 #ifdef SOCK_REFCNT_DEBUG
713 static inline void sk_refcnt_debug_inc(struct sock *sk)
714 {
715         atomic_inc(&sk->sk_prot->socks);
716 }
717 
718 static inline void sk_refcnt_debug_dec(struct sock *sk)
719 {
720         atomic_dec(&sk->sk_prot->socks);
721         printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
722                sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
723 }
724 
725 static inline void sk_refcnt_debug_release(const struct sock *sk)
726 {
727         if (atomic_read(&sk->sk_refcnt) != 1)
728                 printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
729                        sk->sk_prot->name, sk, atomic_read(&sk->sk_refcnt));
730 }
731 #else /* SOCK_REFCNT_DEBUG */
732 #define sk_refcnt_debug_inc(sk) do { } while (0)
733 #define sk_refcnt_debug_dec(sk) do { } while (0)
734 #define sk_refcnt_debug_release(sk) do { } while (0)
735 #endif /* SOCK_REFCNT_DEBUG */
736 
737 
738 #ifdef CONFIG_PROC_FS
739 /* Called with local bh disabled */
740 extern void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
741 extern int sock_prot_inuse_get(struct net *net, struct proto *proto);
742 #else
743 static void inline sock_prot_inuse_add(struct net *net, struct proto *prot,
744                 int inc)
745 {
746 }
747 #endif
748 
749 
750 /* With per-bucket locks this operation is not-atomic, so that
751  * this version is not worse.
752  */
753 static inline void __sk_prot_rehash(struct sock *sk)
754 {
755         sk->sk_prot->unhash(sk);
756         sk->sk_prot->hash(sk);
757 }
758 
759 /* About 10 seconds */
760 #define SOCK_DESTROY_TIME (10*HZ)
761 
762 /* Sockets 0-1023 can't be bound to unless you are superuser */
763 #define PROT_SOCK       1024
764 
765 #define SHUTDOWN_MASK   3
766 #define RCV_SHUTDOWN    1
767 #define SEND_SHUTDOWN   2
768 
769 #define SOCK_SNDBUF_LOCK        1
770 #define SOCK_RCVBUF_LOCK        2
771 #define SOCK_BINDADDR_LOCK      4
772 #define SOCK_BINDPORT_LOCK      8
773 
774 /* sock_iocb: used to kick off async processing of socket ios */
775 struct sock_iocb {
776         struct list_head        list;
777 
778         int                     flags;
779         int                     size;
780         struct socket           *sock;
781         struct sock             *sk;
782         struct scm_cookie       *scm;
783         struct msghdr           *msg, async_msg;
784         struct kiocb            *kiocb;
785 };
786 
787 static inline struct sock_iocb *kiocb_to_siocb(struct kiocb *iocb)
788 {
789         return (struct sock_iocb *)iocb->private;
790 }
791 
792 static inline struct kiocb *siocb_to_kiocb(struct sock_iocb *si)
793 {
794         return si->kiocb;
795 }
796 
797 struct socket_alloc {
798         struct socket socket;
799         struct inode vfs_inode;
800 };
801 
802 static inline struct socket *SOCKET_I(struct inode *inode)
803 {
804         return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
805 }
806 
807 static inline struct inode *SOCK_INODE(struct socket *socket)
808 {
809         return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
810 }
811 
812 /*
813  * Functions for memory accounting
814  */
815 extern int __sk_mem_schedule(struct sock *sk, int size, int kind);
816 extern void __sk_mem_reclaim(struct sock *sk);
817 
818 #define SK_MEM_QUANTUM ((int)PAGE_SIZE)
819 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
820 #define SK_MEM_SEND     0
821 #define SK_MEM_RECV     1
822 
823 static inline int sk_mem_pages(int amt)
824 {
825         return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
826 }
827 
828 static inline int sk_has_account(struct sock *sk)
829 {
830         /* return true if protocol supports memory accounting */
831         return !!sk->sk_prot->memory_allocated;
832 }
833 
834 static inline int sk_wmem_schedule(struct sock *sk, int size)
835 {
836         if (!sk_has_account(sk))
837                 return 1;
838         return size <= sk->sk_forward_alloc ||
839                 __sk_mem_schedule(sk, size, SK_MEM_SEND);
840 }
841 
842 static inline int sk_rmem_schedule(struct sock *sk, int size)
843 {
844         if (!sk_has_account(sk))
845                 return 1;
846         return size <= sk->sk_forward_alloc ||
847                 __sk_mem_schedule(sk, size, SK_MEM_RECV);
848 }
849 
850 static inline void sk_mem_reclaim(struct sock *sk)
851 {
852         if (!sk_has_account(sk))
853                 return;
854         if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
855                 __sk_mem_reclaim(sk);
856 }
857 
858 static inline void sk_mem_reclaim_partial(struct sock *sk)
859 {
860         if (!sk_has_account(sk))
861                 return;
862         if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
863                 __sk_mem_reclaim(sk);
864 }
865 
866 static inline void sk_mem_charge(struct sock *sk, int size)
867 {
868         if (!sk_has_account(sk))
869                 return;
870         sk->sk_forward_alloc -= size;
871 }
872 
873 static inline void sk_mem_uncharge(struct sock *sk, int size)
874 {
875         if (!sk_has_account(sk))
876                 return;
877         sk->sk_forward_alloc += size;
878 }
879 
880 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
881 {
882         sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
883         sk->sk_wmem_queued -= skb->truesize;
884         sk_mem_uncharge(sk, skb->truesize);
885         __kfree_skb(skb);
886 }
887 
888 /* Used by processes to "lock" a socket state, so that
889  * interrupts and bottom half handlers won't change it
890  * from under us. It essentially blocks any incoming
891  * packets, so that we won't get any new data or any
892  * packets that change the state of the socket.
893  *
894  * While locked, BH processing will add new packets to
895  * the backlog queue.  This queue is processed by the
896  * owner of the socket lock right before it is released.
897  *
898  * Since ~2.3.5 it is also exclusive sleep lock serializing
899  * accesses from user process context.
900  */
901 #define sock_owned_by_user(sk)  ((sk)->sk_lock.owned)
902 
903 /*
904  * Macro so as to not evaluate some arguments when
905  * lockdep is not enabled.
906  *
907  * Mark both the sk_lock and the sk_lock.slock as a
908  * per-address-family lock class.
909  */
910 #define sock_lock_init_class_and_name(sk, sname, skey, name, key)       \
911 do {                                                                    \
912         sk->sk_lock.owned = 0;                                          \
913         init_waitqueue_head(&sk->sk_lock.wq);                           \
914         spin_lock_init(&(sk)->sk_lock.slock);                           \
915         debug_check_no_locks_freed((void *)&(sk)->sk_lock,              \
916                         sizeof((sk)->sk_lock));                         \
917         lockdep_set_class_and_name(&(sk)->sk_lock.slock,                \
918                         (skey), (sname));                               \
919         lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);     \
920 } while (0)
921 
922 extern void lock_sock_nested(struct sock *sk, int subclass);
923 
924 static inline void lock_sock(struct sock *sk)
925 {
926         lock_sock_nested(sk, 0);
927 }
928 
929 extern void release_sock(struct sock *sk);
930 
931 /* BH context may only use the following locking interface. */
932 #define bh_lock_sock(__sk)      spin_lock(&((__sk)->sk_lock.slock))
933 #define bh_lock_sock_nested(__sk) \
934                                 spin_lock_nested(&((__sk)->sk_lock.slock), \
935                                 SINGLE_DEPTH_NESTING)
936 #define bh_unlock_sock(__sk)    spin_unlock(&((__sk)->sk_lock.slock))
937 
938 extern struct sock              *sk_alloc(struct net *net, int family,
939                                           gfp_t priority,
940                                           struct proto *prot);
941 extern void                     sk_free(struct sock *sk);
942 extern void                     sk_release_kernel(struct sock *sk);
943 extern struct sock              *sk_clone(const struct sock *sk,
944                                           const gfp_t priority);
945 
946 extern struct sk_buff           *sock_wmalloc(struct sock *sk,
947                                               unsigned long size, int force,
948                                               gfp_t priority);
949 extern struct sk_buff           *sock_rmalloc(struct sock *sk,
950                                               unsigned long size, int force,
951                                               gfp_t priority);
952 extern void                     sock_wfree(struct sk_buff *skb);
953 extern void                     sock_rfree(struct sk_buff *skb);
954 
955 extern int                      sock_setsockopt(struct socket *sock, int level,
956                                                 int op, char __user *optval,
957                                                 unsigned int optlen);
958 
959 extern int                      sock_getsockopt(struct socket *sock, int level,
960                                                 int op, char __user *optval, 
961                                                 int __user *optlen);
962 extern struct sk_buff           *sock_alloc_send_skb(struct sock *sk,
963                                                      unsigned long size,
964                                                      int noblock,
965                                                      int *errcode);
966 extern struct sk_buff           *sock_alloc_send_pskb(struct sock *sk,
967                                                       unsigned long header_len,
968                                                       unsigned long data_len,
969                                                       int noblock,
970                                                       int *errcode);
971 extern void *sock_kmalloc(struct sock *sk, int size,
972                           gfp_t priority);
973 extern void sock_kfree_s(struct sock *sk, void *mem, int size);
974 extern void sk_send_sigurg(struct sock *sk);
975 
976 /*
977  * Functions to fill in entries in struct proto_ops when a protocol
978  * does not implement a particular function.
979  */
980 extern int                      sock_no_bind(struct socket *, 
981                                              struct sockaddr *, int);
982 extern int                      sock_no_connect(struct socket *,
983                                                 struct sockaddr *, int, int);
984 extern int                      sock_no_socketpair(struct socket *,
985                                                    struct socket *);
986 extern int                      sock_no_accept(struct socket *,
987                                                struct socket *, int);
988 extern int                      sock_no_getname(struct socket *,
989                                                 struct sockaddr *, int *, int);
990 extern unsigned int             sock_no_poll(struct file *, struct socket *,
991                                              struct poll_table_struct *);
992 extern int                      sock_no_ioctl(struct socket *, unsigned int,
993                                               unsigned long);
994 extern int                      sock_no_listen(struct socket *, int);
995 extern int                      sock_no_shutdown(struct socket *, int);
996 extern int                      sock_no_getsockopt(struct socket *, int , int,
997                                                    char __user *, int __user *);
998 extern int                      sock_no_setsockopt(struct socket *, int, int,
999                                                    char __user *, unsigned int);
1000 extern int                      sock_no_sendmsg(struct kiocb *, struct socket *,
1001                                                 struct msghdr *, size_t);
1002 extern int                      sock_no_recvmsg(struct kiocb *, struct socket *,
1003                                                 struct msghdr *, size_t, int);
1004 extern int                      sock_no_mmap(struct file *file,
1005                                              struct socket *sock,
1006                                              struct vm_area_struct *vma);
1007 extern ssize_t                  sock_no_sendpage(struct socket *sock,
1008                                                 struct page *page,
1009                                                 int offset, size_t size, 
1010                                                 int flags);
1011 
1012 /*
1013  * Functions to fill in entries in struct proto_ops when a protocol
1014  * uses the inet style.
1015  */
1016 extern int sock_common_getsockopt(struct socket *sock, int level, int optname,
1017                                   char __user *optval, int __user *optlen);
1018 extern int sock_common_recvmsg(struct kiocb *iocb, struct socket *sock,
1019                                struct msghdr *msg, size_t size, int flags);
1020 extern int sock_common_setsockopt(struct socket *sock, int level, int optname,
1021                                   char __user *optval, unsigned int optlen);
1022 extern int compat_sock_common_getsockopt(struct socket *sock, int level,
1023                 int optname, char __user *optval, int __user *optlen);
1024 extern int compat_sock_common_setsockopt(struct socket *sock, int level,
1025                 int optname, char __user *optval, unsigned int optlen);
1026 
1027 extern void sk_common_release(struct sock *sk);
1028 
1029 /*
1030  *      Default socket callbacks and setup code
1031  */
1032  
1033 /* Initialise core socket variables */
1034 extern void sock_init_data(struct socket *sock, struct sock *sk);
1035 
1036 /**
1037  *      sk_filter_release: Release a socket filter
1038  *      @fp: filter to remove
1039  *
1040  *      Remove a filter from a socket and release its resources.
1041  */
1042 
1043 static inline void sk_filter_release(struct sk_filter *fp)
1044 {
1045         if (atomic_dec_and_test(&fp->refcnt))
1046                 kfree(fp);
1047 }
1048 
1049 static inline void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
1050 {
1051         unsigned int size = sk_filter_len(fp);
1052 
1053         atomic_sub(size, &sk->sk_omem_alloc);
1054         sk_filter_release(fp);
1055 }
1056 
1057 static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
1058 {
1059         atomic_inc(&fp->refcnt);
1060         atomic_add(sk_filter_len(fp), &sk->sk_omem_alloc);
1061 }
1062 
1063 /*
1064  * Socket reference counting postulates.
1065  *
1066  * * Each user of socket SHOULD hold a reference count.
1067  * * Each access point to socket (an hash table bucket, reference from a list,
1068  *   running timer, skb in flight MUST hold a reference count.
1069  * * When reference count hits 0, it means it will never increase back.
1070  * * When reference count hits 0, it means that no references from
1071  *   outside exist to this socket and current process on current CPU
1072  *   is last user and may/should destroy this socket.
1073  * * sk_free is called from any context: process, BH, IRQ. When
1074  *   it is called, socket has no references from outside -> sk_free
1075  *   may release descendant resources allocated by the socket, but
1076  *   to the time when it is called, socket is NOT referenced by any
1077  *   hash tables, lists etc.
1078  * * Packets, delivered from outside (from network or from another process)
1079  *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1080  *   when they sit in queue. Otherwise, packets will leak to hole, when
1081  *   socket is looked up by one cpu and unhasing is made by another CPU.
1082  *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1083  *   (leak to backlog). Packet socket does all the processing inside
1084  *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1085  *   use separate SMP lock, so that they are prone too.
1086  */
1087 
1088 /* Ungrab socket and destroy it, if it was the last reference. */
1089 static inline void sock_put(struct sock *sk)
1090 {
1091         if (atomic_dec_and_test(&sk->sk_refcnt))
1092                 sk_free(sk);
1093 }
1094 
1095 extern int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
1096                           const int nested);
1097 
1098 static inline void sk_set_socket(struct sock *sk, struct socket *sock)
1099 {
1100         sk->sk_socket = sock;
1101 }
1102 
1103 /* Detach socket from process context.
1104  * Announce socket dead, detach it from wait queue and inode.
1105  * Note that parent inode held reference count on this struct sock,
1106  * we do not release it in this function, because protocol
1107  * probably wants some additional cleanups or even continuing
1108  * to work with this socket (TCP).
1109  */
1110 static inline void sock_orphan(struct sock *sk)
1111 {
1112         write_lock_bh(&sk->sk_callback_lock);
1113         sock_set_flag(sk, SOCK_DEAD);
1114         sk_set_socket(sk, NULL);
1115         sk->sk_sleep  = NULL;
1116         write_unlock_bh(&sk->sk_callback_lock);
1117 }
1118 
1119 static inline void sock_graft(struct sock *sk, struct socket *parent)
1120 {
1121         write_lock_bh(&sk->sk_callback_lock);
1122         sk->sk_sleep = &parent->wait;
1123         parent->sk = sk;
1124         sk_set_socket(sk, parent);
1125         security_sock_graft(sk, parent);
1126         write_unlock_bh(&sk->sk_callback_lock);
1127 }
1128 
1129 extern int sock_i_uid(struct sock *sk);
1130 extern unsigned long sock_i_ino(struct sock *sk);
1131 
1132 static inline struct dst_entry *
1133 __sk_dst_get(struct sock *sk)
1134 {
1135         return sk->sk_dst_cache;
1136 }
1137 
1138 static inline struct dst_entry *
1139 sk_dst_get(struct sock *sk)
1140 {
1141         struct dst_entry *dst;
1142 
1143         read_lock(&sk->sk_dst_lock);
1144         dst = sk->sk_dst_cache;
1145         if (dst)
1146                 dst_hold(dst);
1147         read_unlock(&sk->sk_dst_lock);
1148         return dst;
1149 }
1150 
1151 static inline void
1152 __sk_dst_set(struct sock *sk, struct dst_entry *dst)
1153 {
1154         struct dst_entry *old_dst;
1155 
1156         old_dst = sk->sk_dst_cache;
1157         sk->sk_dst_cache = dst;
1158         dst_release(old_dst);
1159 }
1160 
1161 static inline void
1162 sk_dst_set(struct sock *sk, struct dst_entry *dst)
1163 {
1164         write_lock(&sk->sk_dst_lock);
1165         __sk_dst_set(sk, dst);
1166         write_unlock(&sk->sk_dst_lock);
1167 }
1168 
1169 static inline void
1170 __sk_dst_reset(struct sock *sk)
1171 {
1172         struct dst_entry *old_dst;
1173 
1174         old_dst = sk->sk_dst_cache;
1175         sk->sk_dst_cache = NULL;
1176         dst_release(old_dst);
1177 }
1178 
1179 static inline void
1180 sk_dst_reset(struct sock *sk)
1181 {
1182         write_lock(&sk->sk_dst_lock);
1183         __sk_dst_reset(sk);
1184         write_unlock(&sk->sk_dst_lock);
1185 }
1186 
1187 extern struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
1188 
1189 extern struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
1190 
1191 static inline int sk_can_gso(const struct sock *sk)
1192 {
1193         return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
1194 }
1195 
1196 extern void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
1197 
1198 static inline int skb_copy_to_page(struct sock *sk, char __user *from,
1199                                    struct sk_buff *skb, struct page *page,
1200                                    int off, int copy)
1201 {
1202         if (skb->ip_summed == CHECKSUM_NONE) {
1203                 int err = 0;
1204                 __wsum csum = csum_and_copy_from_user(from,
1205                                                      page_address(page) + off,
1206                                                             copy, 0, &err);
1207                 if (err)
1208                         return err;
1209                 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1210         } else if (copy_from_user(page_address(page) + off, from, copy))
1211                 return -EFAULT;
1212 
1213         skb->len             += copy;
1214         skb->data_len        += copy;
1215         skb->truesize        += copy;
1216         sk->sk_wmem_queued   += copy;
1217         sk_mem_charge(sk, copy);
1218         return 0;
1219 }
1220 
1221 /**
1222  * sk_wmem_alloc_get - returns write allocations
1223  * @sk: socket
1224  *
1225  * Returns sk_wmem_alloc minus initial offset of one
1226  */
1227 static inline int sk_wmem_alloc_get(const struct sock *sk)
1228 {
1229         return atomic_read(&sk->sk_wmem_alloc) - 1;
1230 }
1231 
1232 /**
1233  * sk_rmem_alloc_get - returns read allocations
1234  * @sk: socket
1235  *
1236  * Returns sk_rmem_alloc
1237  */
1238 static inline int sk_rmem_alloc_get(const struct sock *sk)
1239 {
1240         return atomic_read(&sk->sk_rmem_alloc);
1241 }
1242 
1243 /**
1244  * sk_has_allocations - check if allocations are outstanding
1245  * @sk: socket
1246  *
1247  * Returns true if socket has write or read allocations
1248  */
1249 static inline int sk_has_allocations(const struct sock *sk)
1250 {
1251         return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
1252 }
1253 
1254 /**
1255  * sk_has_sleeper - check if there are any waiting processes
1256  * @sk: socket
1257  *
1258  * Returns true if socket has waiting processes
1259  *
1260  * The purpose of the sk_has_sleeper and sock_poll_wait is to wrap the memory
1261  * barrier call. They were added due to the race found within the tcp code.
1262  *
1263  * Consider following tcp code paths:
1264  *
1265  * CPU1                  CPU2
1266  *
1267  * sys_select            receive packet
1268  *   ...                 ...
1269  *   __add_wait_queue    update tp->rcv_nxt
1270  *   ...                 ...
1271  *   tp->rcv_nxt check   sock_def_readable
1272  *   ...                 {
1273  *   schedule               ...
1274  *                          if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
1275  *                              wake_up_interruptible(sk->sk_sleep)
1276  *                          ...
1277  *                       }
1278  *
1279  * The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
1280  * in its cache, and so does the tp->rcv_nxt update on CPU2 side.  The CPU1
1281  * could then endup calling schedule and sleep forever if there are no more
1282  * data on the socket.
1283  *
1284  * The sk_has_sleeper is always called right after a call to read_lock, so we
1285  * can use smp_mb__after_lock barrier.
1286  */
1287 static inline int sk_has_sleeper(struct sock *sk)
1288 {
1289         /*
1290          * We need to be sure we are in sync with the
1291          * add_wait_queue modifications to the wait queue.
1292          *
1293          * This memory barrier is paired in the sock_poll_wait.
1294          */
1295         smp_mb__after_lock();
1296         return sk->sk_sleep && waitqueue_active(sk->sk_sleep);
1297 }
1298 
1299 /**
1300  * sock_poll_wait - place memory barrier behind the poll_wait call.
1301  * @filp:           file
1302  * @wait_address:   socket wait queue
1303  * @p:              poll_table
1304  *
1305  * See the comments in the sk_has_sleeper function.
1306  */
1307 static inline void sock_poll_wait(struct file *filp,
1308                 wait_queue_head_t *wait_address, poll_table *p)
1309 {
1310         if (p && wait_address) {
1311                 poll_wait(filp, wait_address, p);
1312                 /*
1313                  * We need to be sure we are in sync with the
1314                  * socket flags modification.
1315                  *
1316                  * This memory barrier is paired in the sk_has_sleeper.
1317                 */
1318                 smp_mb();
1319         }
1320 }
1321 
1322 /*
1323  *      Queue a received datagram if it will fit. Stream and sequenced
1324  *      protocols can't normally use this as they need to fit buffers in
1325  *      and play with them.
1326  *
1327  *      Inlined as it's very short and called for pretty much every
1328  *      packet ever received.
1329  */
1330 
1331 static inline void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1332 {
1333         skb_orphan(skb);
1334         skb->sk = sk;
1335         skb->destructor = sock_wfree;
1336         /*
1337          * We used to take a refcount on sk, but following operation
1338          * is enough to guarantee sk_free() wont free this sock until
1339          * all in-flight packets are completed
1340          */
1341         atomic_add(skb->truesize, &sk->sk_wmem_alloc);
1342 }
1343 
1344 static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
1345 {
1346         skb_orphan(skb);
1347         skb->sk = sk;
1348         skb->destructor = sock_rfree;
1349         atomic_add(skb->truesize, &sk->sk_rmem_alloc);
1350         sk_mem_charge(sk, skb->truesize);
1351 }
1352 
1353 extern void sk_reset_timer(struct sock *sk, struct timer_list* timer,
1354                            unsigned long expires);
1355 
1356 extern void sk_stop_timer(struct sock *sk, struct timer_list* timer);
1357 
1358 extern int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
1359 
1360 extern int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
1361 
1362 /*
1363  *      Recover an error report and clear atomically
1364  */
1365  
1366 static inline int sock_error(struct sock *sk)
1367 {
1368         int err;
1369         if (likely(!sk->sk_err))
1370                 return 0;
1371         err = xchg(&sk->sk_err, 0);
1372         return -err;
1373 }
1374 
1375 static inline unsigned long sock_wspace(struct sock *sk)
1376 {
1377         int amt = 0;
1378 
1379         if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
1380                 amt = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
1381                 if (amt < 0) 
1382                         amt = 0;
1383         }
1384         return amt;
1385 }
1386 
1387 static inline void sk_wake_async(struct sock *sk, int how, int band)
1388 {
1389         if (sk->sk_socket && sk->sk_socket->fasync_list)
1390                 sock_wake_async(sk->sk_socket, how, band);
1391 }
1392 
1393 #define SOCK_MIN_SNDBUF 2048
1394 #define SOCK_MIN_RCVBUF 256
1395 
1396 static inline void sk_stream_moderate_sndbuf(struct sock *sk)
1397 {
1398         if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
1399                 sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
1400                 sk->sk_sndbuf = max(sk->sk_sndbuf, SOCK_MIN_SNDBUF);
1401         }
1402 }
1403 
1404 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp);
1405 
1406 static inline struct page *sk_stream_alloc_page(struct sock *sk)
1407 {
1408         struct page *page = NULL;
1409 
1410         page = alloc_pages(sk->sk_allocation, 0);
1411         if (!page) {
1412                 sk->sk_prot->enter_memory_pressure(sk);
1413                 sk_stream_moderate_sndbuf(sk);
1414         }
1415         return page;
1416 }
1417 
1418 /*
1419  *      Default write policy as shown to user space via poll/select/SIGIO
1420  */
1421 static inline int sock_writeable(const struct sock *sk) 
1422 {
1423         return atomic_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
1424 }
1425 
1426 static inline gfp_t gfp_any(void)
1427 {
1428         return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
1429 }
1430 
1431 static inline long sock_rcvtimeo(const struct sock *sk, int noblock)
1432 {
1433         return noblock ? 0 : sk->sk_rcvtimeo;
1434 }
1435 
1436 static inline long sock_sndtimeo(const struct sock *sk, int noblock)
1437 {
1438         return noblock ? 0 : sk->sk_sndtimeo;
1439 }
1440 
1441 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
1442 {
1443         return (waitall ? len : min_t(int, sk->sk_rcvlowat, len)) ? : 1;
1444 }
1445 
1446 /* Alas, with timeout socket operations are not restartable.
1447  * Compare this to poll().
1448  */
1449 static inline int sock_intr_errno(long timeo)
1450 {
1451         return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
1452 }
1453 
1454 extern void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
1455         struct sk_buff *skb);
1456 
1457 static __inline__ void
1458 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
1459 {
1460         ktime_t kt = skb->tstamp;
1461         struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
1462 
1463         /*
1464          * generate control messages if
1465          * - receive time stamping in software requested (SOCK_RCVTSTAMP
1466          *   or SOCK_TIMESTAMPING_RX_SOFTWARE)
1467          * - software time stamp available and wanted
1468          *   (SOCK_TIMESTAMPING_SOFTWARE)
1469          * - hardware time stamps available and wanted
1470          *   (SOCK_TIMESTAMPING_SYS_HARDWARE or
1471          *   SOCK_TIMESTAMPING_RAW_HARDWARE)
1472          */
1473         if (sock_flag(sk, SOCK_RCVTSTAMP) ||
1474             sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE) ||
1475             (kt.tv64 && sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE)) ||
1476             (hwtstamps->hwtstamp.tv64 &&
1477              sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE)) ||
1478             (hwtstamps->syststamp.tv64 &&
1479              sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE)))
1480                 __sock_recv_timestamp(msg, sk, skb);
1481         else
1482                 sk->sk_stamp = kt;
1483 }
1484 
1485 /**
1486  * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
1487  * @msg:        outgoing packet
1488  * @sk:         socket sending this packet
1489  * @shtx:       filled with instructions for time stamping
1490  *
1491  * Currently only depends on SOCK_TIMESTAMPING* flags. Returns error code if
1492  * parameters are invalid.
1493  */
1494 extern int sock_tx_timestamp(struct msghdr *msg,
1495                              struct sock *sk,
1496                              union skb_shared_tx *shtx);
1497 
1498 
1499 /**
1500  * sk_eat_skb - Release a skb if it is no longer needed
1501  * @sk: socket to eat this skb from
1502  * @skb: socket buffer to eat
1503  * @copied_early: flag indicating whether DMA operations copied this data early
1504  *
1505  * This routine must be called with interrupts disabled or with the socket
1506  * locked so that the sk_buff queue operation is ok.
1507 */
1508 #ifdef CONFIG_NET_DMA
1509 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_early)
1510 {
1511         __skb_unlink(skb, &sk->sk_receive_queue);
1512         if (!copied_early)
1513                 __kfree_skb(skb);
1514         else
1515                 __skb_queue_tail(&sk->sk_async_wait_queue, skb);
1516 }
1517 #else
1518 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_early)
1519 {
1520         __skb_unlink(skb, &sk->sk_receive_queue);
1521         __kfree_skb(skb);
1522 }
1523 #endif
1524 
1525 static inline
1526 struct net *sock_net(const struct sock *sk)
1527 {
1528 #ifdef CONFIG_NET_NS
1529         return sk->sk_net;
1530 #else
1531         return &init_net;
1532 #endif
1533 }
1534 
1535 static inline
1536 void sock_net_set(struct sock *sk, struct net *net)
1537 {
1538 #ifdef CONFIG_NET_NS
1539         sk->sk_net = net;
1540 #endif
1541 }
1542 
1543 /*
1544  * Kernel sockets, f.e. rtnl or icmp_socket, are a part of a namespace.
1545  * They should not hold a referrence to a namespace in order to allow
1546  * to stop it.
1547  * Sockets after sk_change_net should be released using sk_release_kernel
1548  */
1549 static inline void sk_change_net(struct sock *sk, struct net *net)
1550 {
1551         put_net(sock_net(sk));
1552         sock_net_set(sk, hold_net(net));
1553 }
1554 
1555 static inline struct sock *skb_steal_sock(struct sk_buff *skb)
1556 {
1557         if (unlikely(skb->sk)) {
1558                 struct sock *sk = skb->sk;
1559 
1560                 skb->destructor = NULL;
1561                 skb->sk = NULL;
1562                 return sk;
1563         }
1564         return NULL;
1565 }
1566 
1567 extern void sock_enable_timestamp(struct sock *sk, int flag);
1568 extern int sock_get_timestamp(struct sock *, struct timeval __user *);
1569 extern int sock_get_timestampns(struct sock *, struct timespec __user *);
1570 
1571 /* 
1572  *      Enable debug/info messages 
1573  */
1574 extern int net_msg_warn;
1575 #define NETDEBUG(fmt, args...) \
1576         do { if (net_msg_warn) printk(fmt,##args); } while (0)
1577 
1578 #define LIMIT_NETDEBUG(fmt, args...) \
1579         do { if (net_msg_warn && net_ratelimit()) printk(fmt,##args); } while(0)
1580 
1581 extern __u32 sysctl_wmem_max;
1582 extern __u32 sysctl_rmem_max;
1583 
1584 extern void sk_init(void);
1585 
1586 extern int sysctl_optmem_max;
1587 
1588 extern __u32 sysctl_wmem_default;
1589 extern __u32 sysctl_rmem_default;
1590 
1591 #endif  /* _SOCK_H */
1592 

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