xref: /linux/net/core/sock.c (revision b3b77c8caef1750ebeea1054e39e358550ea9f55)
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  *		Generic socket support routines. Memory allocators, socket lock/release
7  *		handler for protocols to use and generic option handler.
8  *
9  *
10  * Authors:	Ross Biro
11  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12  *		Florian La Roche, <flla@stud.uni-sb.de>
13  *		Alan Cox, <A.Cox@swansea.ac.uk>
14  *
15  * Fixes:
16  *		Alan Cox	: 	Numerous verify_area() problems
17  *		Alan Cox	:	Connecting on a connecting socket
18  *					now returns an error for tcp.
19  *		Alan Cox	:	sock->protocol is set correctly.
20  *					and is not sometimes left as 0.
21  *		Alan Cox	:	connect handles icmp errors on a
22  *					connect properly. Unfortunately there
23  *					is a restart syscall nasty there. I
24  *					can't match BSD without hacking the C
25  *					library. Ideas urgently sought!
26  *		Alan Cox	:	Disallow bind() to addresses that are
27  *					not ours - especially broadcast ones!!
28  *		Alan Cox	:	Socket 1024 _IS_ ok for users. (fencepost)
29  *		Alan Cox	:	sock_wfree/sock_rfree don't destroy sockets,
30  *					instead they leave that for the DESTROY timer.
31  *		Alan Cox	:	Clean up error flag in accept
32  *		Alan Cox	:	TCP ack handling is buggy, the DESTROY timer
33  *					was buggy. Put a remove_sock() in the handler
34  *					for memory when we hit 0. Also altered the timer
35  *					code. The ACK stuff can wait and needs major
36  *					TCP layer surgery.
37  *		Alan Cox	:	Fixed TCP ack bug, removed remove sock
38  *					and fixed timer/inet_bh race.
39  *		Alan Cox	:	Added zapped flag for TCP
40  *		Alan Cox	:	Move kfree_skb into skbuff.c and tidied up surplus code
41  *		Alan Cox	:	for new sk_buff allocations wmalloc/rmalloc now call alloc_skb
42  *		Alan Cox	:	kfree_s calls now are kfree_skbmem so we can track skb resources
43  *		Alan Cox	:	Supports socket option broadcast now as does udp. Packet and raw need fixing.
44  *		Alan Cox	:	Added RCVBUF,SNDBUF size setting. It suddenly occurred to me how easy it was so...
45  *		Rick Sladkey	:	Relaxed UDP rules for matching packets.
46  *		C.E.Hawkins	:	IFF_PROMISC/SIOCGHWADDR support
47  *	Pauline Middelink	:	identd support
48  *		Alan Cox	:	Fixed connect() taking signals I think.
49  *		Alan Cox	:	SO_LINGER supported
50  *		Alan Cox	:	Error reporting fixes
51  *		Anonymous	:	inet_create tidied up (sk->reuse setting)
52  *		Alan Cox	:	inet sockets don't set sk->type!
53  *		Alan Cox	:	Split socket option code
54  *		Alan Cox	:	Callbacks
55  *		Alan Cox	:	Nagle flag for Charles & Johannes stuff
56  *		Alex		:	Removed restriction on inet fioctl
57  *		Alan Cox	:	Splitting INET from NET core
58  *		Alan Cox	:	Fixed bogus SO_TYPE handling in getsockopt()
59  *		Adam Caldwell	:	Missing return in SO_DONTROUTE/SO_DEBUG code
60  *		Alan Cox	:	Split IP from generic code
61  *		Alan Cox	:	New kfree_skbmem()
62  *		Alan Cox	:	Make SO_DEBUG superuser only.
63  *		Alan Cox	:	Allow anyone to clear SO_DEBUG
64  *					(compatibility fix)
65  *		Alan Cox	:	Added optimistic memory grabbing for AF_UNIX throughput.
66  *		Alan Cox	:	Allocator for a socket is settable.
67  *		Alan Cox	:	SO_ERROR includes soft errors.
68  *		Alan Cox	:	Allow NULL arguments on some SO_ opts
69  *		Alan Cox	: 	Generic socket allocation to make hooks
70  *					easier (suggested by Craig Metz).
71  *		Michael Pall	:	SO_ERROR returns positive errno again
72  *              Steve Whitehouse:       Added default destructor to free
73  *                                      protocol private data.
74  *              Steve Whitehouse:       Added various other default routines
75  *                                      common to several socket families.
76  *              Chris Evans     :       Call suser() check last on F_SETOWN
77  *		Jay Schulist	:	Added SO_ATTACH_FILTER and SO_DETACH_FILTER.
78  *		Andi Kleen	:	Add sock_kmalloc()/sock_kfree_s()
79  *		Andi Kleen	:	Fix write_space callback
80  *		Chris Evans	:	Security fixes - signedness again
81  *		Arnaldo C. Melo :       cleanups, use skb_queue_purge
82  *
83  * To Fix:
84  *
85  *
86  *		This program is free software; you can redistribute it and/or
87  *		modify it under the terms of the GNU General Public License
88  *		as published by the Free Software Foundation; either version
89  *		2 of the License, or (at your option) any later version.
90  */
91 
92 #include <linux/capability.h>
93 #include <linux/errno.h>
94 #include <linux/types.h>
95 #include <linux/socket.h>
96 #include <linux/in.h>
97 #include <linux/kernel.h>
98 #include <linux/module.h>
99 #include <linux/proc_fs.h>
100 #include <linux/seq_file.h>
101 #include <linux/sched.h>
102 #include <linux/timer.h>
103 #include <linux/string.h>
104 #include <linux/sockios.h>
105 #include <linux/net.h>
106 #include <linux/mm.h>
107 #include <linux/slab.h>
108 #include <linux/interrupt.h>
109 #include <linux/poll.h>
110 #include <linux/tcp.h>
111 #include <linux/init.h>
112 #include <linux/highmem.h>
113 
114 #include <asm/uaccess.h>
115 #include <asm/system.h>
116 
117 #include <linux/netdevice.h>
118 #include <net/protocol.h>
119 #include <linux/skbuff.h>
120 #include <net/net_namespace.h>
121 #include <net/request_sock.h>
122 #include <net/sock.h>
123 #include <linux/net_tstamp.h>
124 #include <net/xfrm.h>
125 #include <linux/ipsec.h>
126 
127 #include <linux/filter.h>
128 
129 #ifdef CONFIG_INET
130 #include <net/tcp.h>
131 #endif
132 
133 /*
134  * Each address family might have different locking rules, so we have
135  * one slock key per address family:
136  */
137 static struct lock_class_key af_family_keys[AF_MAX];
138 static struct lock_class_key af_family_slock_keys[AF_MAX];
139 
140 /*
141  * Make lock validator output more readable. (we pre-construct these
142  * strings build-time, so that runtime initialization of socket
143  * locks is fast):
144  */
145 static const char *const af_family_key_strings[AF_MAX+1] = {
146   "sk_lock-AF_UNSPEC", "sk_lock-AF_UNIX"     , "sk_lock-AF_INET"     ,
147   "sk_lock-AF_AX25"  , "sk_lock-AF_IPX"      , "sk_lock-AF_APPLETALK",
148   "sk_lock-AF_NETROM", "sk_lock-AF_BRIDGE"   , "sk_lock-AF_ATMPVC"   ,
149   "sk_lock-AF_X25"   , "sk_lock-AF_INET6"    , "sk_lock-AF_ROSE"     ,
150   "sk_lock-AF_DECnet", "sk_lock-AF_NETBEUI"  , "sk_lock-AF_SECURITY" ,
151   "sk_lock-AF_KEY"   , "sk_lock-AF_NETLINK"  , "sk_lock-AF_PACKET"   ,
152   "sk_lock-AF_ASH"   , "sk_lock-AF_ECONET"   , "sk_lock-AF_ATMSVC"   ,
153   "sk_lock-AF_RDS"   , "sk_lock-AF_SNA"      , "sk_lock-AF_IRDA"     ,
154   "sk_lock-AF_PPPOX" , "sk_lock-AF_WANPIPE"  , "sk_lock-AF_LLC"      ,
155   "sk_lock-27"       , "sk_lock-28"          , "sk_lock-AF_CAN"      ,
156   "sk_lock-AF_TIPC"  , "sk_lock-AF_BLUETOOTH", "sk_lock-IUCV"        ,
157   "sk_lock-AF_RXRPC" , "sk_lock-AF_ISDN"     , "sk_lock-AF_PHONET"   ,
158   "sk_lock-AF_IEEE802154",
159   "sk_lock-AF_MAX"
160 };
161 static const char *const af_family_slock_key_strings[AF_MAX+1] = {
162   "slock-AF_UNSPEC", "slock-AF_UNIX"     , "slock-AF_INET"     ,
163   "slock-AF_AX25"  , "slock-AF_IPX"      , "slock-AF_APPLETALK",
164   "slock-AF_NETROM", "slock-AF_BRIDGE"   , "slock-AF_ATMPVC"   ,
165   "slock-AF_X25"   , "slock-AF_INET6"    , "slock-AF_ROSE"     ,
166   "slock-AF_DECnet", "slock-AF_NETBEUI"  , "slock-AF_SECURITY" ,
167   "slock-AF_KEY"   , "slock-AF_NETLINK"  , "slock-AF_PACKET"   ,
168   "slock-AF_ASH"   , "slock-AF_ECONET"   , "slock-AF_ATMSVC"   ,
169   "slock-AF_RDS"   , "slock-AF_SNA"      , "slock-AF_IRDA"     ,
170   "slock-AF_PPPOX" , "slock-AF_WANPIPE"  , "slock-AF_LLC"      ,
171   "slock-27"       , "slock-28"          , "slock-AF_CAN"      ,
172   "slock-AF_TIPC"  , "slock-AF_BLUETOOTH", "slock-AF_IUCV"     ,
173   "slock-AF_RXRPC" , "slock-AF_ISDN"     , "slock-AF_PHONET"   ,
174   "slock-AF_IEEE802154",
175   "slock-AF_MAX"
176 };
177 static const char *const af_family_clock_key_strings[AF_MAX+1] = {
178   "clock-AF_UNSPEC", "clock-AF_UNIX"     , "clock-AF_INET"     ,
179   "clock-AF_AX25"  , "clock-AF_IPX"      , "clock-AF_APPLETALK",
180   "clock-AF_NETROM", "clock-AF_BRIDGE"   , "clock-AF_ATMPVC"   ,
181   "clock-AF_X25"   , "clock-AF_INET6"    , "clock-AF_ROSE"     ,
182   "clock-AF_DECnet", "clock-AF_NETBEUI"  , "clock-AF_SECURITY" ,
183   "clock-AF_KEY"   , "clock-AF_NETLINK"  , "clock-AF_PACKET"   ,
184   "clock-AF_ASH"   , "clock-AF_ECONET"   , "clock-AF_ATMSVC"   ,
185   "clock-AF_RDS"   , "clock-AF_SNA"      , "clock-AF_IRDA"     ,
186   "clock-AF_PPPOX" , "clock-AF_WANPIPE"  , "clock-AF_LLC"      ,
187   "clock-27"       , "clock-28"          , "clock-AF_CAN"      ,
188   "clock-AF_TIPC"  , "clock-AF_BLUETOOTH", "clock-AF_IUCV"     ,
189   "clock-AF_RXRPC" , "clock-AF_ISDN"     , "clock-AF_PHONET"   ,
190   "clock-AF_IEEE802154",
191   "clock-AF_MAX"
192 };
193 
194 /*
195  * sk_callback_lock locking rules are per-address-family,
196  * so split the lock classes by using a per-AF key:
197  */
198 static struct lock_class_key af_callback_keys[AF_MAX];
199 
200 /* Take into consideration the size of the struct sk_buff overhead in the
201  * determination of these values, since that is non-constant across
202  * platforms.  This makes socket queueing behavior and performance
203  * not depend upon such differences.
204  */
205 #define _SK_MEM_PACKETS		256
206 #define _SK_MEM_OVERHEAD	(sizeof(struct sk_buff) + 256)
207 #define SK_WMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
208 #define SK_RMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
209 
210 /* Run time adjustable parameters. */
211 __u32 sysctl_wmem_max __read_mostly = SK_WMEM_MAX;
212 __u32 sysctl_rmem_max __read_mostly = SK_RMEM_MAX;
213 __u32 sysctl_wmem_default __read_mostly = SK_WMEM_MAX;
214 __u32 sysctl_rmem_default __read_mostly = SK_RMEM_MAX;
215 
216 /* Maximal space eaten by iovec or ancilliary data plus some space */
217 int sysctl_optmem_max __read_mostly = sizeof(unsigned long)*(2*UIO_MAXIOV+512);
218 EXPORT_SYMBOL(sysctl_optmem_max);
219 
220 static int sock_set_timeout(long *timeo_p, char __user *optval, int optlen)
221 {
222 	struct timeval tv;
223 
224 	if (optlen < sizeof(tv))
225 		return -EINVAL;
226 	if (copy_from_user(&tv, optval, sizeof(tv)))
227 		return -EFAULT;
228 	if (tv.tv_usec < 0 || tv.tv_usec >= USEC_PER_SEC)
229 		return -EDOM;
230 
231 	if (tv.tv_sec < 0) {
232 		static int warned __read_mostly;
233 
234 		*timeo_p = 0;
235 		if (warned < 10 && net_ratelimit()) {
236 			warned++;
237 			printk(KERN_INFO "sock_set_timeout: `%s' (pid %d) "
238 			       "tries to set negative timeout\n",
239 				current->comm, task_pid_nr(current));
240 		}
241 		return 0;
242 	}
243 	*timeo_p = MAX_SCHEDULE_TIMEOUT;
244 	if (tv.tv_sec == 0 && tv.tv_usec == 0)
245 		return 0;
246 	if (tv.tv_sec < (MAX_SCHEDULE_TIMEOUT/HZ - 1))
247 		*timeo_p = tv.tv_sec*HZ + (tv.tv_usec+(1000000/HZ-1))/(1000000/HZ);
248 	return 0;
249 }
250 
251 static void sock_warn_obsolete_bsdism(const char *name)
252 {
253 	static int warned;
254 	static char warncomm[TASK_COMM_LEN];
255 	if (strcmp(warncomm, current->comm) && warned < 5) {
256 		strcpy(warncomm,  current->comm);
257 		printk(KERN_WARNING "process `%s' is using obsolete "
258 		       "%s SO_BSDCOMPAT\n", warncomm, name);
259 		warned++;
260 	}
261 }
262 
263 static void sock_disable_timestamp(struct sock *sk, int flag)
264 {
265 	if (sock_flag(sk, flag)) {
266 		sock_reset_flag(sk, flag);
267 		if (!sock_flag(sk, SOCK_TIMESTAMP) &&
268 		    !sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE)) {
269 			net_disable_timestamp();
270 		}
271 	}
272 }
273 
274 
275 int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
276 {
277 	int err;
278 	int skb_len;
279 	unsigned long flags;
280 	struct sk_buff_head *list = &sk->sk_receive_queue;
281 
282 	/* Cast sk->rcvbuf to unsigned... It's pointless, but reduces
283 	   number of warnings when compiling with -W --ANK
284 	 */
285 	if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
286 	    (unsigned)sk->sk_rcvbuf) {
287 		atomic_inc(&sk->sk_drops);
288 		return -ENOMEM;
289 	}
290 
291 	err = sk_filter(sk, skb);
292 	if (err)
293 		return err;
294 
295 	if (!sk_rmem_schedule(sk, skb->truesize)) {
296 		atomic_inc(&sk->sk_drops);
297 		return -ENOBUFS;
298 	}
299 
300 	skb->dev = NULL;
301 	skb_set_owner_r(skb, sk);
302 
303 	/* Cache the SKB length before we tack it onto the receive
304 	 * queue.  Once it is added it no longer belongs to us and
305 	 * may be freed by other threads of control pulling packets
306 	 * from the queue.
307 	 */
308 	skb_len = skb->len;
309 
310 	/* we escape from rcu protected region, make sure we dont leak
311 	 * a norefcounted dst
312 	 */
313 	skb_dst_force(skb);
314 
315 	spin_lock_irqsave(&list->lock, flags);
316 	skb->dropcount = atomic_read(&sk->sk_drops);
317 	__skb_queue_tail(list, skb);
318 	spin_unlock_irqrestore(&list->lock, flags);
319 
320 	if (!sock_flag(sk, SOCK_DEAD))
321 		sk->sk_data_ready(sk, skb_len);
322 	return 0;
323 }
324 EXPORT_SYMBOL(sock_queue_rcv_skb);
325 
326 int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested)
327 {
328 	int rc = NET_RX_SUCCESS;
329 
330 	if (sk_filter(sk, skb))
331 		goto discard_and_relse;
332 
333 	skb->dev = NULL;
334 
335 	if (sk_rcvqueues_full(sk, skb)) {
336 		atomic_inc(&sk->sk_drops);
337 		goto discard_and_relse;
338 	}
339 	if (nested)
340 		bh_lock_sock_nested(sk);
341 	else
342 		bh_lock_sock(sk);
343 	if (!sock_owned_by_user(sk)) {
344 		/*
345 		 * trylock + unlock semantics:
346 		 */
347 		mutex_acquire(&sk->sk_lock.dep_map, 0, 1, _RET_IP_);
348 
349 		rc = sk_backlog_rcv(sk, skb);
350 
351 		mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
352 	} else if (sk_add_backlog(sk, skb)) {
353 		bh_unlock_sock(sk);
354 		atomic_inc(&sk->sk_drops);
355 		goto discard_and_relse;
356 	}
357 
358 	bh_unlock_sock(sk);
359 out:
360 	sock_put(sk);
361 	return rc;
362 discard_and_relse:
363 	kfree_skb(skb);
364 	goto out;
365 }
366 EXPORT_SYMBOL(sk_receive_skb);
367 
368 void sk_reset_txq(struct sock *sk)
369 {
370 	sk_tx_queue_clear(sk);
371 }
372 EXPORT_SYMBOL(sk_reset_txq);
373 
374 struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie)
375 {
376 	struct dst_entry *dst = __sk_dst_get(sk);
377 
378 	if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
379 		sk_tx_queue_clear(sk);
380 		rcu_assign_pointer(sk->sk_dst_cache, NULL);
381 		dst_release(dst);
382 		return NULL;
383 	}
384 
385 	return dst;
386 }
387 EXPORT_SYMBOL(__sk_dst_check);
388 
389 struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie)
390 {
391 	struct dst_entry *dst = sk_dst_get(sk);
392 
393 	if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
394 		sk_dst_reset(sk);
395 		dst_release(dst);
396 		return NULL;
397 	}
398 
399 	return dst;
400 }
401 EXPORT_SYMBOL(sk_dst_check);
402 
403 static int sock_bindtodevice(struct sock *sk, char __user *optval, int optlen)
404 {
405 	int ret = -ENOPROTOOPT;
406 #ifdef CONFIG_NETDEVICES
407 	struct net *net = sock_net(sk);
408 	char devname[IFNAMSIZ];
409 	int index;
410 
411 	/* Sorry... */
412 	ret = -EPERM;
413 	if (!capable(CAP_NET_RAW))
414 		goto out;
415 
416 	ret = -EINVAL;
417 	if (optlen < 0)
418 		goto out;
419 
420 	/* Bind this socket to a particular device like "eth0",
421 	 * as specified in the passed interface name. If the
422 	 * name is "" or the option length is zero the socket
423 	 * is not bound.
424 	 */
425 	if (optlen > IFNAMSIZ - 1)
426 		optlen = IFNAMSIZ - 1;
427 	memset(devname, 0, sizeof(devname));
428 
429 	ret = -EFAULT;
430 	if (copy_from_user(devname, optval, optlen))
431 		goto out;
432 
433 	index = 0;
434 	if (devname[0] != '\0') {
435 		struct net_device *dev;
436 
437 		rcu_read_lock();
438 		dev = dev_get_by_name_rcu(net, devname);
439 		if (dev)
440 			index = dev->ifindex;
441 		rcu_read_unlock();
442 		ret = -ENODEV;
443 		if (!dev)
444 			goto out;
445 	}
446 
447 	lock_sock(sk);
448 	sk->sk_bound_dev_if = index;
449 	sk_dst_reset(sk);
450 	release_sock(sk);
451 
452 	ret = 0;
453 
454 out:
455 #endif
456 
457 	return ret;
458 }
459 
460 static inline void sock_valbool_flag(struct sock *sk, int bit, int valbool)
461 {
462 	if (valbool)
463 		sock_set_flag(sk, bit);
464 	else
465 		sock_reset_flag(sk, bit);
466 }
467 
468 /*
469  *	This is meant for all protocols to use and covers goings on
470  *	at the socket level. Everything here is generic.
471  */
472 
473 int sock_setsockopt(struct socket *sock, int level, int optname,
474 		    char __user *optval, unsigned int optlen)
475 {
476 	struct sock *sk = sock->sk;
477 	int val;
478 	int valbool;
479 	struct linger ling;
480 	int ret = 0;
481 
482 	/*
483 	 *	Options without arguments
484 	 */
485 
486 	if (optname == SO_BINDTODEVICE)
487 		return sock_bindtodevice(sk, optval, optlen);
488 
489 	if (optlen < sizeof(int))
490 		return -EINVAL;
491 
492 	if (get_user(val, (int __user *)optval))
493 		return -EFAULT;
494 
495 	valbool = val ? 1 : 0;
496 
497 	lock_sock(sk);
498 
499 	switch (optname) {
500 	case SO_DEBUG:
501 		if (val && !capable(CAP_NET_ADMIN))
502 			ret = -EACCES;
503 		else
504 			sock_valbool_flag(sk, SOCK_DBG, valbool);
505 		break;
506 	case SO_REUSEADDR:
507 		sk->sk_reuse = valbool;
508 		break;
509 	case SO_TYPE:
510 	case SO_PROTOCOL:
511 	case SO_DOMAIN:
512 	case SO_ERROR:
513 		ret = -ENOPROTOOPT;
514 		break;
515 	case SO_DONTROUTE:
516 		sock_valbool_flag(sk, SOCK_LOCALROUTE, valbool);
517 		break;
518 	case SO_BROADCAST:
519 		sock_valbool_flag(sk, SOCK_BROADCAST, valbool);
520 		break;
521 	case SO_SNDBUF:
522 		/* Don't error on this BSD doesn't and if you think
523 		   about it this is right. Otherwise apps have to
524 		   play 'guess the biggest size' games. RCVBUF/SNDBUF
525 		   are treated in BSD as hints */
526 
527 		if (val > sysctl_wmem_max)
528 			val = sysctl_wmem_max;
529 set_sndbuf:
530 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
531 		if ((val * 2) < SOCK_MIN_SNDBUF)
532 			sk->sk_sndbuf = SOCK_MIN_SNDBUF;
533 		else
534 			sk->sk_sndbuf = val * 2;
535 
536 		/*
537 		 *	Wake up sending tasks if we
538 		 *	upped the value.
539 		 */
540 		sk->sk_write_space(sk);
541 		break;
542 
543 	case SO_SNDBUFFORCE:
544 		if (!capable(CAP_NET_ADMIN)) {
545 			ret = -EPERM;
546 			break;
547 		}
548 		goto set_sndbuf;
549 
550 	case SO_RCVBUF:
551 		/* Don't error on this BSD doesn't and if you think
552 		   about it this is right. Otherwise apps have to
553 		   play 'guess the biggest size' games. RCVBUF/SNDBUF
554 		   are treated in BSD as hints */
555 
556 		if (val > sysctl_rmem_max)
557 			val = sysctl_rmem_max;
558 set_rcvbuf:
559 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
560 		/*
561 		 * We double it on the way in to account for
562 		 * "struct sk_buff" etc. overhead.   Applications
563 		 * assume that the SO_RCVBUF setting they make will
564 		 * allow that much actual data to be received on that
565 		 * socket.
566 		 *
567 		 * Applications are unaware that "struct sk_buff" and
568 		 * other overheads allocate from the receive buffer
569 		 * during socket buffer allocation.
570 		 *
571 		 * And after considering the possible alternatives,
572 		 * returning the value we actually used in getsockopt
573 		 * is the most desirable behavior.
574 		 */
575 		if ((val * 2) < SOCK_MIN_RCVBUF)
576 			sk->sk_rcvbuf = SOCK_MIN_RCVBUF;
577 		else
578 			sk->sk_rcvbuf = val * 2;
579 		break;
580 
581 	case SO_RCVBUFFORCE:
582 		if (!capable(CAP_NET_ADMIN)) {
583 			ret = -EPERM;
584 			break;
585 		}
586 		goto set_rcvbuf;
587 
588 	case SO_KEEPALIVE:
589 #ifdef CONFIG_INET
590 		if (sk->sk_protocol == IPPROTO_TCP)
591 			tcp_set_keepalive(sk, valbool);
592 #endif
593 		sock_valbool_flag(sk, SOCK_KEEPOPEN, valbool);
594 		break;
595 
596 	case SO_OOBINLINE:
597 		sock_valbool_flag(sk, SOCK_URGINLINE, valbool);
598 		break;
599 
600 	case SO_NO_CHECK:
601 		sk->sk_no_check = valbool;
602 		break;
603 
604 	case SO_PRIORITY:
605 		if ((val >= 0 && val <= 6) || capable(CAP_NET_ADMIN))
606 			sk->sk_priority = val;
607 		else
608 			ret = -EPERM;
609 		break;
610 
611 	case SO_LINGER:
612 		if (optlen < sizeof(ling)) {
613 			ret = -EINVAL;	/* 1003.1g */
614 			break;
615 		}
616 		if (copy_from_user(&ling, optval, sizeof(ling))) {
617 			ret = -EFAULT;
618 			break;
619 		}
620 		if (!ling.l_onoff)
621 			sock_reset_flag(sk, SOCK_LINGER);
622 		else {
623 #if (BITS_PER_LONG == 32)
624 			if ((unsigned int)ling.l_linger >= MAX_SCHEDULE_TIMEOUT/HZ)
625 				sk->sk_lingertime = MAX_SCHEDULE_TIMEOUT;
626 			else
627 #endif
628 				sk->sk_lingertime = (unsigned int)ling.l_linger * HZ;
629 			sock_set_flag(sk, SOCK_LINGER);
630 		}
631 		break;
632 
633 	case SO_BSDCOMPAT:
634 		sock_warn_obsolete_bsdism("setsockopt");
635 		break;
636 
637 	case SO_PASSCRED:
638 		if (valbool)
639 			set_bit(SOCK_PASSCRED, &sock->flags);
640 		else
641 			clear_bit(SOCK_PASSCRED, &sock->flags);
642 		break;
643 
644 	case SO_TIMESTAMP:
645 	case SO_TIMESTAMPNS:
646 		if (valbool)  {
647 			if (optname == SO_TIMESTAMP)
648 				sock_reset_flag(sk, SOCK_RCVTSTAMPNS);
649 			else
650 				sock_set_flag(sk, SOCK_RCVTSTAMPNS);
651 			sock_set_flag(sk, SOCK_RCVTSTAMP);
652 			sock_enable_timestamp(sk, SOCK_TIMESTAMP);
653 		} else {
654 			sock_reset_flag(sk, SOCK_RCVTSTAMP);
655 			sock_reset_flag(sk, SOCK_RCVTSTAMPNS);
656 		}
657 		break;
658 
659 	case SO_TIMESTAMPING:
660 		if (val & ~SOF_TIMESTAMPING_MASK) {
661 			ret = -EINVAL;
662 			break;
663 		}
664 		sock_valbool_flag(sk, SOCK_TIMESTAMPING_TX_HARDWARE,
665 				  val & SOF_TIMESTAMPING_TX_HARDWARE);
666 		sock_valbool_flag(sk, SOCK_TIMESTAMPING_TX_SOFTWARE,
667 				  val & SOF_TIMESTAMPING_TX_SOFTWARE);
668 		sock_valbool_flag(sk, SOCK_TIMESTAMPING_RX_HARDWARE,
669 				  val & SOF_TIMESTAMPING_RX_HARDWARE);
670 		if (val & SOF_TIMESTAMPING_RX_SOFTWARE)
671 			sock_enable_timestamp(sk,
672 					      SOCK_TIMESTAMPING_RX_SOFTWARE);
673 		else
674 			sock_disable_timestamp(sk,
675 					       SOCK_TIMESTAMPING_RX_SOFTWARE);
676 		sock_valbool_flag(sk, SOCK_TIMESTAMPING_SOFTWARE,
677 				  val & SOF_TIMESTAMPING_SOFTWARE);
678 		sock_valbool_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE,
679 				  val & SOF_TIMESTAMPING_SYS_HARDWARE);
680 		sock_valbool_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE,
681 				  val & SOF_TIMESTAMPING_RAW_HARDWARE);
682 		break;
683 
684 	case SO_RCVLOWAT:
685 		if (val < 0)
686 			val = INT_MAX;
687 		sk->sk_rcvlowat = val ? : 1;
688 		break;
689 
690 	case SO_RCVTIMEO:
691 		ret = sock_set_timeout(&sk->sk_rcvtimeo, optval, optlen);
692 		break;
693 
694 	case SO_SNDTIMEO:
695 		ret = sock_set_timeout(&sk->sk_sndtimeo, optval, optlen);
696 		break;
697 
698 	case SO_ATTACH_FILTER:
699 		ret = -EINVAL;
700 		if (optlen == sizeof(struct sock_fprog)) {
701 			struct sock_fprog fprog;
702 
703 			ret = -EFAULT;
704 			if (copy_from_user(&fprog, optval, sizeof(fprog)))
705 				break;
706 
707 			ret = sk_attach_filter(&fprog, sk);
708 		}
709 		break;
710 
711 	case SO_DETACH_FILTER:
712 		ret = sk_detach_filter(sk);
713 		break;
714 
715 	case SO_PASSSEC:
716 		if (valbool)
717 			set_bit(SOCK_PASSSEC, &sock->flags);
718 		else
719 			clear_bit(SOCK_PASSSEC, &sock->flags);
720 		break;
721 	case SO_MARK:
722 		if (!capable(CAP_NET_ADMIN))
723 			ret = -EPERM;
724 		else
725 			sk->sk_mark = val;
726 		break;
727 
728 		/* We implement the SO_SNDLOWAT etc to
729 		   not be settable (1003.1g 5.3) */
730 	case SO_RXQ_OVFL:
731 		if (valbool)
732 			sock_set_flag(sk, SOCK_RXQ_OVFL);
733 		else
734 			sock_reset_flag(sk, SOCK_RXQ_OVFL);
735 		break;
736 	default:
737 		ret = -ENOPROTOOPT;
738 		break;
739 	}
740 	release_sock(sk);
741 	return ret;
742 }
743 EXPORT_SYMBOL(sock_setsockopt);
744 
745 
746 int sock_getsockopt(struct socket *sock, int level, int optname,
747 		    char __user *optval, int __user *optlen)
748 {
749 	struct sock *sk = sock->sk;
750 
751 	union {
752 		int val;
753 		struct linger ling;
754 		struct timeval tm;
755 	} v;
756 
757 	int lv = sizeof(int);
758 	int len;
759 
760 	if (get_user(len, optlen))
761 		return -EFAULT;
762 	if (len < 0)
763 		return -EINVAL;
764 
765 	memset(&v, 0, sizeof(v));
766 
767 	switch (optname) {
768 	case SO_DEBUG:
769 		v.val = sock_flag(sk, SOCK_DBG);
770 		break;
771 
772 	case SO_DONTROUTE:
773 		v.val = sock_flag(sk, SOCK_LOCALROUTE);
774 		break;
775 
776 	case SO_BROADCAST:
777 		v.val = !!sock_flag(sk, SOCK_BROADCAST);
778 		break;
779 
780 	case SO_SNDBUF:
781 		v.val = sk->sk_sndbuf;
782 		break;
783 
784 	case SO_RCVBUF:
785 		v.val = sk->sk_rcvbuf;
786 		break;
787 
788 	case SO_REUSEADDR:
789 		v.val = sk->sk_reuse;
790 		break;
791 
792 	case SO_KEEPALIVE:
793 		v.val = !!sock_flag(sk, SOCK_KEEPOPEN);
794 		break;
795 
796 	case SO_TYPE:
797 		v.val = sk->sk_type;
798 		break;
799 
800 	case SO_PROTOCOL:
801 		v.val = sk->sk_protocol;
802 		break;
803 
804 	case SO_DOMAIN:
805 		v.val = sk->sk_family;
806 		break;
807 
808 	case SO_ERROR:
809 		v.val = -sock_error(sk);
810 		if (v.val == 0)
811 			v.val = xchg(&sk->sk_err_soft, 0);
812 		break;
813 
814 	case SO_OOBINLINE:
815 		v.val = !!sock_flag(sk, SOCK_URGINLINE);
816 		break;
817 
818 	case SO_NO_CHECK:
819 		v.val = sk->sk_no_check;
820 		break;
821 
822 	case SO_PRIORITY:
823 		v.val = sk->sk_priority;
824 		break;
825 
826 	case SO_LINGER:
827 		lv		= sizeof(v.ling);
828 		v.ling.l_onoff	= !!sock_flag(sk, SOCK_LINGER);
829 		v.ling.l_linger	= sk->sk_lingertime / HZ;
830 		break;
831 
832 	case SO_BSDCOMPAT:
833 		sock_warn_obsolete_bsdism("getsockopt");
834 		break;
835 
836 	case SO_TIMESTAMP:
837 		v.val = sock_flag(sk, SOCK_RCVTSTAMP) &&
838 				!sock_flag(sk, SOCK_RCVTSTAMPNS);
839 		break;
840 
841 	case SO_TIMESTAMPNS:
842 		v.val = sock_flag(sk, SOCK_RCVTSTAMPNS);
843 		break;
844 
845 	case SO_TIMESTAMPING:
846 		v.val = 0;
847 		if (sock_flag(sk, SOCK_TIMESTAMPING_TX_HARDWARE))
848 			v.val |= SOF_TIMESTAMPING_TX_HARDWARE;
849 		if (sock_flag(sk, SOCK_TIMESTAMPING_TX_SOFTWARE))
850 			v.val |= SOF_TIMESTAMPING_TX_SOFTWARE;
851 		if (sock_flag(sk, SOCK_TIMESTAMPING_RX_HARDWARE))
852 			v.val |= SOF_TIMESTAMPING_RX_HARDWARE;
853 		if (sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE))
854 			v.val |= SOF_TIMESTAMPING_RX_SOFTWARE;
855 		if (sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE))
856 			v.val |= SOF_TIMESTAMPING_SOFTWARE;
857 		if (sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE))
858 			v.val |= SOF_TIMESTAMPING_SYS_HARDWARE;
859 		if (sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE))
860 			v.val |= SOF_TIMESTAMPING_RAW_HARDWARE;
861 		break;
862 
863 	case SO_RCVTIMEO:
864 		lv = sizeof(struct timeval);
865 		if (sk->sk_rcvtimeo == MAX_SCHEDULE_TIMEOUT) {
866 			v.tm.tv_sec = 0;
867 			v.tm.tv_usec = 0;
868 		} else {
869 			v.tm.tv_sec = sk->sk_rcvtimeo / HZ;
870 			v.tm.tv_usec = ((sk->sk_rcvtimeo % HZ) * 1000000) / HZ;
871 		}
872 		break;
873 
874 	case SO_SNDTIMEO:
875 		lv = sizeof(struct timeval);
876 		if (sk->sk_sndtimeo == MAX_SCHEDULE_TIMEOUT) {
877 			v.tm.tv_sec = 0;
878 			v.tm.tv_usec = 0;
879 		} else {
880 			v.tm.tv_sec = sk->sk_sndtimeo / HZ;
881 			v.tm.tv_usec = ((sk->sk_sndtimeo % HZ) * 1000000) / HZ;
882 		}
883 		break;
884 
885 	case SO_RCVLOWAT:
886 		v.val = sk->sk_rcvlowat;
887 		break;
888 
889 	case SO_SNDLOWAT:
890 		v.val = 1;
891 		break;
892 
893 	case SO_PASSCRED:
894 		v.val = test_bit(SOCK_PASSCRED, &sock->flags) ? 1 : 0;
895 		break;
896 
897 	case SO_PEERCRED:
898 		if (len > sizeof(sk->sk_peercred))
899 			len = sizeof(sk->sk_peercred);
900 		if (copy_to_user(optval, &sk->sk_peercred, len))
901 			return -EFAULT;
902 		goto lenout;
903 
904 	case SO_PEERNAME:
905 	{
906 		char address[128];
907 
908 		if (sock->ops->getname(sock, (struct sockaddr *)address, &lv, 2))
909 			return -ENOTCONN;
910 		if (lv < len)
911 			return -EINVAL;
912 		if (copy_to_user(optval, address, len))
913 			return -EFAULT;
914 		goto lenout;
915 	}
916 
917 	/* Dubious BSD thing... Probably nobody even uses it, but
918 	 * the UNIX standard wants it for whatever reason... -DaveM
919 	 */
920 	case SO_ACCEPTCONN:
921 		v.val = sk->sk_state == TCP_LISTEN;
922 		break;
923 
924 	case SO_PASSSEC:
925 		v.val = test_bit(SOCK_PASSSEC, &sock->flags) ? 1 : 0;
926 		break;
927 
928 	case SO_PEERSEC:
929 		return security_socket_getpeersec_stream(sock, optval, optlen, len);
930 
931 	case SO_MARK:
932 		v.val = sk->sk_mark;
933 		break;
934 
935 	case SO_RXQ_OVFL:
936 		v.val = !!sock_flag(sk, SOCK_RXQ_OVFL);
937 		break;
938 
939 	default:
940 		return -ENOPROTOOPT;
941 	}
942 
943 	if (len > lv)
944 		len = lv;
945 	if (copy_to_user(optval, &v, len))
946 		return -EFAULT;
947 lenout:
948 	if (put_user(len, optlen))
949 		return -EFAULT;
950 	return 0;
951 }
952 
953 /*
954  * Initialize an sk_lock.
955  *
956  * (We also register the sk_lock with the lock validator.)
957  */
958 static inline void sock_lock_init(struct sock *sk)
959 {
960 	sock_lock_init_class_and_name(sk,
961 			af_family_slock_key_strings[sk->sk_family],
962 			af_family_slock_keys + sk->sk_family,
963 			af_family_key_strings[sk->sk_family],
964 			af_family_keys + sk->sk_family);
965 }
966 
967 /*
968  * Copy all fields from osk to nsk but nsk->sk_refcnt must not change yet,
969  * even temporarly, because of RCU lookups. sk_node should also be left as is.
970  */
971 static void sock_copy(struct sock *nsk, const struct sock *osk)
972 {
973 #ifdef CONFIG_SECURITY_NETWORK
974 	void *sptr = nsk->sk_security;
975 #endif
976 	BUILD_BUG_ON(offsetof(struct sock, sk_copy_start) !=
977 		     sizeof(osk->sk_node) + sizeof(osk->sk_refcnt) +
978 		     sizeof(osk->sk_tx_queue_mapping));
979 	memcpy(&nsk->sk_copy_start, &osk->sk_copy_start,
980 	       osk->sk_prot->obj_size - offsetof(struct sock, sk_copy_start));
981 #ifdef CONFIG_SECURITY_NETWORK
982 	nsk->sk_security = sptr;
983 	security_sk_clone(osk, nsk);
984 #endif
985 }
986 
987 static struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority,
988 		int family)
989 {
990 	struct sock *sk;
991 	struct kmem_cache *slab;
992 
993 	slab = prot->slab;
994 	if (slab != NULL) {
995 		sk = kmem_cache_alloc(slab, priority & ~__GFP_ZERO);
996 		if (!sk)
997 			return sk;
998 		if (priority & __GFP_ZERO) {
999 			/*
1000 			 * caches using SLAB_DESTROY_BY_RCU should let
1001 			 * sk_node.next un-modified. Special care is taken
1002 			 * when initializing object to zero.
1003 			 */
1004 			if (offsetof(struct sock, sk_node.next) != 0)
1005 				memset(sk, 0, offsetof(struct sock, sk_node.next));
1006 			memset(&sk->sk_node.pprev, 0,
1007 			       prot->obj_size - offsetof(struct sock,
1008 							 sk_node.pprev));
1009 		}
1010 	}
1011 	else
1012 		sk = kmalloc(prot->obj_size, priority);
1013 
1014 	if (sk != NULL) {
1015 		kmemcheck_annotate_bitfield(sk, flags);
1016 
1017 		if (security_sk_alloc(sk, family, priority))
1018 			goto out_free;
1019 
1020 		if (!try_module_get(prot->owner))
1021 			goto out_free_sec;
1022 		sk_tx_queue_clear(sk);
1023 	}
1024 
1025 	return sk;
1026 
1027 out_free_sec:
1028 	security_sk_free(sk);
1029 out_free:
1030 	if (slab != NULL)
1031 		kmem_cache_free(slab, sk);
1032 	else
1033 		kfree(sk);
1034 	return NULL;
1035 }
1036 
1037 static void sk_prot_free(struct proto *prot, struct sock *sk)
1038 {
1039 	struct kmem_cache *slab;
1040 	struct module *owner;
1041 
1042 	owner = prot->owner;
1043 	slab = prot->slab;
1044 
1045 	security_sk_free(sk);
1046 	if (slab != NULL)
1047 		kmem_cache_free(slab, sk);
1048 	else
1049 		kfree(sk);
1050 	module_put(owner);
1051 }
1052 
1053 /**
1054  *	sk_alloc - All socket objects are allocated here
1055  *	@net: the applicable net namespace
1056  *	@family: protocol family
1057  *	@priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
1058  *	@prot: struct proto associated with this new sock instance
1059  */
1060 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
1061 		      struct proto *prot)
1062 {
1063 	struct sock *sk;
1064 
1065 	sk = sk_prot_alloc(prot, priority | __GFP_ZERO, family);
1066 	if (sk) {
1067 		sk->sk_family = family;
1068 		/*
1069 		 * See comment in struct sock definition to understand
1070 		 * why we need sk_prot_creator -acme
1071 		 */
1072 		sk->sk_prot = sk->sk_prot_creator = prot;
1073 		sock_lock_init(sk);
1074 		sock_net_set(sk, get_net(net));
1075 		atomic_set(&sk->sk_wmem_alloc, 1);
1076 	}
1077 
1078 	return sk;
1079 }
1080 EXPORT_SYMBOL(sk_alloc);
1081 
1082 static void __sk_free(struct sock *sk)
1083 {
1084 	struct sk_filter *filter;
1085 
1086 	if (sk->sk_destruct)
1087 		sk->sk_destruct(sk);
1088 
1089 	filter = rcu_dereference_check(sk->sk_filter,
1090 				       atomic_read(&sk->sk_wmem_alloc) == 0);
1091 	if (filter) {
1092 		sk_filter_uncharge(sk, filter);
1093 		rcu_assign_pointer(sk->sk_filter, NULL);
1094 	}
1095 
1096 	sock_disable_timestamp(sk, SOCK_TIMESTAMP);
1097 	sock_disable_timestamp(sk, SOCK_TIMESTAMPING_RX_SOFTWARE);
1098 
1099 	if (atomic_read(&sk->sk_omem_alloc))
1100 		printk(KERN_DEBUG "%s: optmem leakage (%d bytes) detected.\n",
1101 		       __func__, atomic_read(&sk->sk_omem_alloc));
1102 
1103 	put_net(sock_net(sk));
1104 	sk_prot_free(sk->sk_prot_creator, sk);
1105 }
1106 
1107 void sk_free(struct sock *sk)
1108 {
1109 	/*
1110 	 * We substract one from sk_wmem_alloc and can know if
1111 	 * some packets are still in some tx queue.
1112 	 * If not null, sock_wfree() will call __sk_free(sk) later
1113 	 */
1114 	if (atomic_dec_and_test(&sk->sk_wmem_alloc))
1115 		__sk_free(sk);
1116 }
1117 EXPORT_SYMBOL(sk_free);
1118 
1119 /*
1120  * Last sock_put should drop referrence to sk->sk_net. It has already
1121  * been dropped in sk_change_net. Taking referrence to stopping namespace
1122  * is not an option.
1123  * Take referrence to a socket to remove it from hash _alive_ and after that
1124  * destroy it in the context of init_net.
1125  */
1126 void sk_release_kernel(struct sock *sk)
1127 {
1128 	if (sk == NULL || sk->sk_socket == NULL)
1129 		return;
1130 
1131 	sock_hold(sk);
1132 	sock_release(sk->sk_socket);
1133 	release_net(sock_net(sk));
1134 	sock_net_set(sk, get_net(&init_net));
1135 	sock_put(sk);
1136 }
1137 EXPORT_SYMBOL(sk_release_kernel);
1138 
1139 struct sock *sk_clone(const struct sock *sk, const gfp_t priority)
1140 {
1141 	struct sock *newsk;
1142 
1143 	newsk = sk_prot_alloc(sk->sk_prot, priority, sk->sk_family);
1144 	if (newsk != NULL) {
1145 		struct sk_filter *filter;
1146 
1147 		sock_copy(newsk, sk);
1148 
1149 		/* SANITY */
1150 		get_net(sock_net(newsk));
1151 		sk_node_init(&newsk->sk_node);
1152 		sock_lock_init(newsk);
1153 		bh_lock_sock(newsk);
1154 		newsk->sk_backlog.head	= newsk->sk_backlog.tail = NULL;
1155 		newsk->sk_backlog.len = 0;
1156 
1157 		atomic_set(&newsk->sk_rmem_alloc, 0);
1158 		/*
1159 		 * sk_wmem_alloc set to one (see sk_free() and sock_wfree())
1160 		 */
1161 		atomic_set(&newsk->sk_wmem_alloc, 1);
1162 		atomic_set(&newsk->sk_omem_alloc, 0);
1163 		skb_queue_head_init(&newsk->sk_receive_queue);
1164 		skb_queue_head_init(&newsk->sk_write_queue);
1165 #ifdef CONFIG_NET_DMA
1166 		skb_queue_head_init(&newsk->sk_async_wait_queue);
1167 #endif
1168 
1169 		spin_lock_init(&newsk->sk_dst_lock);
1170 		rwlock_init(&newsk->sk_callback_lock);
1171 		lockdep_set_class_and_name(&newsk->sk_callback_lock,
1172 				af_callback_keys + newsk->sk_family,
1173 				af_family_clock_key_strings[newsk->sk_family]);
1174 
1175 		newsk->sk_dst_cache	= NULL;
1176 		newsk->sk_wmem_queued	= 0;
1177 		newsk->sk_forward_alloc = 0;
1178 		newsk->sk_send_head	= NULL;
1179 		newsk->sk_userlocks	= sk->sk_userlocks & ~SOCK_BINDPORT_LOCK;
1180 
1181 		sock_reset_flag(newsk, SOCK_DONE);
1182 		skb_queue_head_init(&newsk->sk_error_queue);
1183 
1184 		filter = newsk->sk_filter;
1185 		if (filter != NULL)
1186 			sk_filter_charge(newsk, filter);
1187 
1188 		if (unlikely(xfrm_sk_clone_policy(newsk))) {
1189 			/* It is still raw copy of parent, so invalidate
1190 			 * destructor and make plain sk_free() */
1191 			newsk->sk_destruct = NULL;
1192 			sk_free(newsk);
1193 			newsk = NULL;
1194 			goto out;
1195 		}
1196 
1197 		newsk->sk_err	   = 0;
1198 		newsk->sk_priority = 0;
1199 		/*
1200 		 * Before updating sk_refcnt, we must commit prior changes to memory
1201 		 * (Documentation/RCU/rculist_nulls.txt for details)
1202 		 */
1203 		smp_wmb();
1204 		atomic_set(&newsk->sk_refcnt, 2);
1205 
1206 		/*
1207 		 * Increment the counter in the same struct proto as the master
1208 		 * sock (sk_refcnt_debug_inc uses newsk->sk_prot->socks, that
1209 		 * is the same as sk->sk_prot->socks, as this field was copied
1210 		 * with memcpy).
1211 		 *
1212 		 * This _changes_ the previous behaviour, where
1213 		 * tcp_create_openreq_child always was incrementing the
1214 		 * equivalent to tcp_prot->socks (inet_sock_nr), so this have
1215 		 * to be taken into account in all callers. -acme
1216 		 */
1217 		sk_refcnt_debug_inc(newsk);
1218 		sk_set_socket(newsk, NULL);
1219 		newsk->sk_wq = NULL;
1220 
1221 		if (newsk->sk_prot->sockets_allocated)
1222 			percpu_counter_inc(newsk->sk_prot->sockets_allocated);
1223 
1224 		if (sock_flag(newsk, SOCK_TIMESTAMP) ||
1225 		    sock_flag(newsk, SOCK_TIMESTAMPING_RX_SOFTWARE))
1226 			net_enable_timestamp();
1227 	}
1228 out:
1229 	return newsk;
1230 }
1231 EXPORT_SYMBOL_GPL(sk_clone);
1232 
1233 void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
1234 {
1235 	__sk_dst_set(sk, dst);
1236 	sk->sk_route_caps = dst->dev->features;
1237 	if (sk->sk_route_caps & NETIF_F_GSO)
1238 		sk->sk_route_caps |= NETIF_F_GSO_SOFTWARE;
1239 	sk->sk_route_caps &= ~sk->sk_route_nocaps;
1240 	if (sk_can_gso(sk)) {
1241 		if (dst->header_len) {
1242 			sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
1243 		} else {
1244 			sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
1245 			sk->sk_gso_max_size = dst->dev->gso_max_size;
1246 		}
1247 	}
1248 }
1249 EXPORT_SYMBOL_GPL(sk_setup_caps);
1250 
1251 void __init sk_init(void)
1252 {
1253 	if (totalram_pages <= 4096) {
1254 		sysctl_wmem_max = 32767;
1255 		sysctl_rmem_max = 32767;
1256 		sysctl_wmem_default = 32767;
1257 		sysctl_rmem_default = 32767;
1258 	} else if (totalram_pages >= 131072) {
1259 		sysctl_wmem_max = 131071;
1260 		sysctl_rmem_max = 131071;
1261 	}
1262 }
1263 
1264 /*
1265  *	Simple resource managers for sockets.
1266  */
1267 
1268 
1269 /*
1270  * Write buffer destructor automatically called from kfree_skb.
1271  */
1272 void sock_wfree(struct sk_buff *skb)
1273 {
1274 	struct sock *sk = skb->sk;
1275 	unsigned int len = skb->truesize;
1276 
1277 	if (!sock_flag(sk, SOCK_USE_WRITE_QUEUE)) {
1278 		/*
1279 		 * Keep a reference on sk_wmem_alloc, this will be released
1280 		 * after sk_write_space() call
1281 		 */
1282 		atomic_sub(len - 1, &sk->sk_wmem_alloc);
1283 		sk->sk_write_space(sk);
1284 		len = 1;
1285 	}
1286 	/*
1287 	 * if sk_wmem_alloc reaches 0, we must finish what sk_free()
1288 	 * could not do because of in-flight packets
1289 	 */
1290 	if (atomic_sub_and_test(len, &sk->sk_wmem_alloc))
1291 		__sk_free(sk);
1292 }
1293 EXPORT_SYMBOL(sock_wfree);
1294 
1295 /*
1296  * Read buffer destructor automatically called from kfree_skb.
1297  */
1298 void sock_rfree(struct sk_buff *skb)
1299 {
1300 	struct sock *sk = skb->sk;
1301 
1302 	atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
1303 	sk_mem_uncharge(skb->sk, skb->truesize);
1304 }
1305 EXPORT_SYMBOL(sock_rfree);
1306 
1307 
1308 int sock_i_uid(struct sock *sk)
1309 {
1310 	int uid;
1311 
1312 	read_lock(&sk->sk_callback_lock);
1313 	uid = sk->sk_socket ? SOCK_INODE(sk->sk_socket)->i_uid : 0;
1314 	read_unlock(&sk->sk_callback_lock);
1315 	return uid;
1316 }
1317 EXPORT_SYMBOL(sock_i_uid);
1318 
1319 unsigned long sock_i_ino(struct sock *sk)
1320 {
1321 	unsigned long ino;
1322 
1323 	read_lock(&sk->sk_callback_lock);
1324 	ino = sk->sk_socket ? SOCK_INODE(sk->sk_socket)->i_ino : 0;
1325 	read_unlock(&sk->sk_callback_lock);
1326 	return ino;
1327 }
1328 EXPORT_SYMBOL(sock_i_ino);
1329 
1330 /*
1331  * Allocate a skb from the socket's send buffer.
1332  */
1333 struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
1334 			     gfp_t priority)
1335 {
1336 	if (force || atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) {
1337 		struct sk_buff *skb = alloc_skb(size, priority);
1338 		if (skb) {
1339 			skb_set_owner_w(skb, sk);
1340 			return skb;
1341 		}
1342 	}
1343 	return NULL;
1344 }
1345 EXPORT_SYMBOL(sock_wmalloc);
1346 
1347 /*
1348  * Allocate a skb from the socket's receive buffer.
1349  */
1350 struct sk_buff *sock_rmalloc(struct sock *sk, unsigned long size, int force,
1351 			     gfp_t priority)
1352 {
1353 	if (force || atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf) {
1354 		struct sk_buff *skb = alloc_skb(size, priority);
1355 		if (skb) {
1356 			skb_set_owner_r(skb, sk);
1357 			return skb;
1358 		}
1359 	}
1360 	return NULL;
1361 }
1362 
1363 /*
1364  * Allocate a memory block from the socket's option memory buffer.
1365  */
1366 void *sock_kmalloc(struct sock *sk, int size, gfp_t priority)
1367 {
1368 	if ((unsigned)size <= sysctl_optmem_max &&
1369 	    atomic_read(&sk->sk_omem_alloc) + size < sysctl_optmem_max) {
1370 		void *mem;
1371 		/* First do the add, to avoid the race if kmalloc
1372 		 * might sleep.
1373 		 */
1374 		atomic_add(size, &sk->sk_omem_alloc);
1375 		mem = kmalloc(size, priority);
1376 		if (mem)
1377 			return mem;
1378 		atomic_sub(size, &sk->sk_omem_alloc);
1379 	}
1380 	return NULL;
1381 }
1382 EXPORT_SYMBOL(sock_kmalloc);
1383 
1384 /*
1385  * Free an option memory block.
1386  */
1387 void sock_kfree_s(struct sock *sk, void *mem, int size)
1388 {
1389 	kfree(mem);
1390 	atomic_sub(size, &sk->sk_omem_alloc);
1391 }
1392 EXPORT_SYMBOL(sock_kfree_s);
1393 
1394 /* It is almost wait_for_tcp_memory minus release_sock/lock_sock.
1395    I think, these locks should be removed for datagram sockets.
1396  */
1397 static long sock_wait_for_wmem(struct sock *sk, long timeo)
1398 {
1399 	DEFINE_WAIT(wait);
1400 
1401 	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1402 	for (;;) {
1403 		if (!timeo)
1404 			break;
1405 		if (signal_pending(current))
1406 			break;
1407 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1408 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1409 		if (atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf)
1410 			break;
1411 		if (sk->sk_shutdown & SEND_SHUTDOWN)
1412 			break;
1413 		if (sk->sk_err)
1414 			break;
1415 		timeo = schedule_timeout(timeo);
1416 	}
1417 	finish_wait(sk_sleep(sk), &wait);
1418 	return timeo;
1419 }
1420 
1421 
1422 /*
1423  *	Generic send/receive buffer handlers
1424  */
1425 
1426 struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
1427 				     unsigned long data_len, int noblock,
1428 				     int *errcode)
1429 {
1430 	struct sk_buff *skb;
1431 	gfp_t gfp_mask;
1432 	long timeo;
1433 	int err;
1434 
1435 	gfp_mask = sk->sk_allocation;
1436 	if (gfp_mask & __GFP_WAIT)
1437 		gfp_mask |= __GFP_REPEAT;
1438 
1439 	timeo = sock_sndtimeo(sk, noblock);
1440 	while (1) {
1441 		err = sock_error(sk);
1442 		if (err != 0)
1443 			goto failure;
1444 
1445 		err = -EPIPE;
1446 		if (sk->sk_shutdown & SEND_SHUTDOWN)
1447 			goto failure;
1448 
1449 		if (atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) {
1450 			skb = alloc_skb(header_len, gfp_mask);
1451 			if (skb) {
1452 				int npages;
1453 				int i;
1454 
1455 				/* No pages, we're done... */
1456 				if (!data_len)
1457 					break;
1458 
1459 				npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
1460 				skb->truesize += data_len;
1461 				skb_shinfo(skb)->nr_frags = npages;
1462 				for (i = 0; i < npages; i++) {
1463 					struct page *page;
1464 					skb_frag_t *frag;
1465 
1466 					page = alloc_pages(sk->sk_allocation, 0);
1467 					if (!page) {
1468 						err = -ENOBUFS;
1469 						skb_shinfo(skb)->nr_frags = i;
1470 						kfree_skb(skb);
1471 						goto failure;
1472 					}
1473 
1474 					frag = &skb_shinfo(skb)->frags[i];
1475 					frag->page = page;
1476 					frag->page_offset = 0;
1477 					frag->size = (data_len >= PAGE_SIZE ?
1478 						      PAGE_SIZE :
1479 						      data_len);
1480 					data_len -= PAGE_SIZE;
1481 				}
1482 
1483 				/* Full success... */
1484 				break;
1485 			}
1486 			err = -ENOBUFS;
1487 			goto failure;
1488 		}
1489 		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
1490 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1491 		err = -EAGAIN;
1492 		if (!timeo)
1493 			goto failure;
1494 		if (signal_pending(current))
1495 			goto interrupted;
1496 		timeo = sock_wait_for_wmem(sk, timeo);
1497 	}
1498 
1499 	skb_set_owner_w(skb, sk);
1500 	return skb;
1501 
1502 interrupted:
1503 	err = sock_intr_errno(timeo);
1504 failure:
1505 	*errcode = err;
1506 	return NULL;
1507 }
1508 EXPORT_SYMBOL(sock_alloc_send_pskb);
1509 
1510 struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size,
1511 				    int noblock, int *errcode)
1512 {
1513 	return sock_alloc_send_pskb(sk, size, 0, noblock, errcode);
1514 }
1515 EXPORT_SYMBOL(sock_alloc_send_skb);
1516 
1517 static void __lock_sock(struct sock *sk)
1518 {
1519 	DEFINE_WAIT(wait);
1520 
1521 	for (;;) {
1522 		prepare_to_wait_exclusive(&sk->sk_lock.wq, &wait,
1523 					TASK_UNINTERRUPTIBLE);
1524 		spin_unlock_bh(&sk->sk_lock.slock);
1525 		schedule();
1526 		spin_lock_bh(&sk->sk_lock.slock);
1527 		if (!sock_owned_by_user(sk))
1528 			break;
1529 	}
1530 	finish_wait(&sk->sk_lock.wq, &wait);
1531 }
1532 
1533 static void __release_sock(struct sock *sk)
1534 {
1535 	struct sk_buff *skb = sk->sk_backlog.head;
1536 
1537 	do {
1538 		sk->sk_backlog.head = sk->sk_backlog.tail = NULL;
1539 		bh_unlock_sock(sk);
1540 
1541 		do {
1542 			struct sk_buff *next = skb->next;
1543 
1544 			WARN_ON_ONCE(skb_dst_is_noref(skb));
1545 			skb->next = NULL;
1546 			sk_backlog_rcv(sk, skb);
1547 
1548 			/*
1549 			 * We are in process context here with softirqs
1550 			 * disabled, use cond_resched_softirq() to preempt.
1551 			 * This is safe to do because we've taken the backlog
1552 			 * queue private:
1553 			 */
1554 			cond_resched_softirq();
1555 
1556 			skb = next;
1557 		} while (skb != NULL);
1558 
1559 		bh_lock_sock(sk);
1560 	} while ((skb = sk->sk_backlog.head) != NULL);
1561 
1562 	/*
1563 	 * Doing the zeroing here guarantee we can not loop forever
1564 	 * while a wild producer attempts to flood us.
1565 	 */
1566 	sk->sk_backlog.len = 0;
1567 }
1568 
1569 /**
1570  * sk_wait_data - wait for data to arrive at sk_receive_queue
1571  * @sk:    sock to wait on
1572  * @timeo: for how long
1573  *
1574  * Now socket state including sk->sk_err is changed only under lock,
1575  * hence we may omit checks after joining wait queue.
1576  * We check receive queue before schedule() only as optimization;
1577  * it is very likely that release_sock() added new data.
1578  */
1579 int sk_wait_data(struct sock *sk, long *timeo)
1580 {
1581 	int rc;
1582 	DEFINE_WAIT(wait);
1583 
1584 	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1585 	set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1586 	rc = sk_wait_event(sk, timeo, !skb_queue_empty(&sk->sk_receive_queue));
1587 	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1588 	finish_wait(sk_sleep(sk), &wait);
1589 	return rc;
1590 }
1591 EXPORT_SYMBOL(sk_wait_data);
1592 
1593 /**
1594  *	__sk_mem_schedule - increase sk_forward_alloc and memory_allocated
1595  *	@sk: socket
1596  *	@size: memory size to allocate
1597  *	@kind: allocation type
1598  *
1599  *	If kind is SK_MEM_SEND, it means wmem allocation. Otherwise it means
1600  *	rmem allocation. This function assumes that protocols which have
1601  *	memory_pressure use sk_wmem_queued as write buffer accounting.
1602  */
1603 int __sk_mem_schedule(struct sock *sk, int size, int kind)
1604 {
1605 	struct proto *prot = sk->sk_prot;
1606 	int amt = sk_mem_pages(size);
1607 	int allocated;
1608 
1609 	sk->sk_forward_alloc += amt * SK_MEM_QUANTUM;
1610 	allocated = atomic_add_return(amt, prot->memory_allocated);
1611 
1612 	/* Under limit. */
1613 	if (allocated <= prot->sysctl_mem[0]) {
1614 		if (prot->memory_pressure && *prot->memory_pressure)
1615 			*prot->memory_pressure = 0;
1616 		return 1;
1617 	}
1618 
1619 	/* Under pressure. */
1620 	if (allocated > prot->sysctl_mem[1])
1621 		if (prot->enter_memory_pressure)
1622 			prot->enter_memory_pressure(sk);
1623 
1624 	/* Over hard limit. */
1625 	if (allocated > prot->sysctl_mem[2])
1626 		goto suppress_allocation;
1627 
1628 	/* guarantee minimum buffer size under pressure */
1629 	if (kind == SK_MEM_RECV) {
1630 		if (atomic_read(&sk->sk_rmem_alloc) < prot->sysctl_rmem[0])
1631 			return 1;
1632 	} else { /* SK_MEM_SEND */
1633 		if (sk->sk_type == SOCK_STREAM) {
1634 			if (sk->sk_wmem_queued < prot->sysctl_wmem[0])
1635 				return 1;
1636 		} else if (atomic_read(&sk->sk_wmem_alloc) <
1637 			   prot->sysctl_wmem[0])
1638 				return 1;
1639 	}
1640 
1641 	if (prot->memory_pressure) {
1642 		int alloc;
1643 
1644 		if (!*prot->memory_pressure)
1645 			return 1;
1646 		alloc = percpu_counter_read_positive(prot->sockets_allocated);
1647 		if (prot->sysctl_mem[2] > alloc *
1648 		    sk_mem_pages(sk->sk_wmem_queued +
1649 				 atomic_read(&sk->sk_rmem_alloc) +
1650 				 sk->sk_forward_alloc))
1651 			return 1;
1652 	}
1653 
1654 suppress_allocation:
1655 
1656 	if (kind == SK_MEM_SEND && sk->sk_type == SOCK_STREAM) {
1657 		sk_stream_moderate_sndbuf(sk);
1658 
1659 		/* Fail only if socket is _under_ its sndbuf.
1660 		 * In this case we cannot block, so that we have to fail.
1661 		 */
1662 		if (sk->sk_wmem_queued + size >= sk->sk_sndbuf)
1663 			return 1;
1664 	}
1665 
1666 	/* Alas. Undo changes. */
1667 	sk->sk_forward_alloc -= amt * SK_MEM_QUANTUM;
1668 	atomic_sub(amt, prot->memory_allocated);
1669 	return 0;
1670 }
1671 EXPORT_SYMBOL(__sk_mem_schedule);
1672 
1673 /**
1674  *	__sk_reclaim - reclaim memory_allocated
1675  *	@sk: socket
1676  */
1677 void __sk_mem_reclaim(struct sock *sk)
1678 {
1679 	struct proto *prot = sk->sk_prot;
1680 
1681 	atomic_sub(sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT,
1682 		   prot->memory_allocated);
1683 	sk->sk_forward_alloc &= SK_MEM_QUANTUM - 1;
1684 
1685 	if (prot->memory_pressure && *prot->memory_pressure &&
1686 	    (atomic_read(prot->memory_allocated) < prot->sysctl_mem[0]))
1687 		*prot->memory_pressure = 0;
1688 }
1689 EXPORT_SYMBOL(__sk_mem_reclaim);
1690 
1691 
1692 /*
1693  * Set of default routines for initialising struct proto_ops when
1694  * the protocol does not support a particular function. In certain
1695  * cases where it makes no sense for a protocol to have a "do nothing"
1696  * function, some default processing is provided.
1697  */
1698 
1699 int sock_no_bind(struct socket *sock, struct sockaddr *saddr, int len)
1700 {
1701 	return -EOPNOTSUPP;
1702 }
1703 EXPORT_SYMBOL(sock_no_bind);
1704 
1705 int sock_no_connect(struct socket *sock, struct sockaddr *saddr,
1706 		    int len, int flags)
1707 {
1708 	return -EOPNOTSUPP;
1709 }
1710 EXPORT_SYMBOL(sock_no_connect);
1711 
1712 int sock_no_socketpair(struct socket *sock1, struct socket *sock2)
1713 {
1714 	return -EOPNOTSUPP;
1715 }
1716 EXPORT_SYMBOL(sock_no_socketpair);
1717 
1718 int sock_no_accept(struct socket *sock, struct socket *newsock, int flags)
1719 {
1720 	return -EOPNOTSUPP;
1721 }
1722 EXPORT_SYMBOL(sock_no_accept);
1723 
1724 int sock_no_getname(struct socket *sock, struct sockaddr *saddr,
1725 		    int *len, int peer)
1726 {
1727 	return -EOPNOTSUPP;
1728 }
1729 EXPORT_SYMBOL(sock_no_getname);
1730 
1731 unsigned int sock_no_poll(struct file *file, struct socket *sock, poll_table *pt)
1732 {
1733 	return 0;
1734 }
1735 EXPORT_SYMBOL(sock_no_poll);
1736 
1737 int sock_no_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1738 {
1739 	return -EOPNOTSUPP;
1740 }
1741 EXPORT_SYMBOL(sock_no_ioctl);
1742 
1743 int sock_no_listen(struct socket *sock, int backlog)
1744 {
1745 	return -EOPNOTSUPP;
1746 }
1747 EXPORT_SYMBOL(sock_no_listen);
1748 
1749 int sock_no_shutdown(struct socket *sock, int how)
1750 {
1751 	return -EOPNOTSUPP;
1752 }
1753 EXPORT_SYMBOL(sock_no_shutdown);
1754 
1755 int sock_no_setsockopt(struct socket *sock, int level, int optname,
1756 		    char __user *optval, unsigned int optlen)
1757 {
1758 	return -EOPNOTSUPP;
1759 }
1760 EXPORT_SYMBOL(sock_no_setsockopt);
1761 
1762 int sock_no_getsockopt(struct socket *sock, int level, int optname,
1763 		    char __user *optval, int __user *optlen)
1764 {
1765 	return -EOPNOTSUPP;
1766 }
1767 EXPORT_SYMBOL(sock_no_getsockopt);
1768 
1769 int sock_no_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
1770 		    size_t len)
1771 {
1772 	return -EOPNOTSUPP;
1773 }
1774 EXPORT_SYMBOL(sock_no_sendmsg);
1775 
1776 int sock_no_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
1777 		    size_t len, int flags)
1778 {
1779 	return -EOPNOTSUPP;
1780 }
1781 EXPORT_SYMBOL(sock_no_recvmsg);
1782 
1783 int sock_no_mmap(struct file *file, struct socket *sock, struct vm_area_struct *vma)
1784 {
1785 	/* Mirror missing mmap method error code */
1786 	return -ENODEV;
1787 }
1788 EXPORT_SYMBOL(sock_no_mmap);
1789 
1790 ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags)
1791 {
1792 	ssize_t res;
1793 	struct msghdr msg = {.msg_flags = flags};
1794 	struct kvec iov;
1795 	char *kaddr = kmap(page);
1796 	iov.iov_base = kaddr + offset;
1797 	iov.iov_len = size;
1798 	res = kernel_sendmsg(sock, &msg, &iov, 1, size);
1799 	kunmap(page);
1800 	return res;
1801 }
1802 EXPORT_SYMBOL(sock_no_sendpage);
1803 
1804 /*
1805  *	Default Socket Callbacks
1806  */
1807 
1808 static void sock_def_wakeup(struct sock *sk)
1809 {
1810 	struct socket_wq *wq;
1811 
1812 	rcu_read_lock();
1813 	wq = rcu_dereference(sk->sk_wq);
1814 	if (wq_has_sleeper(wq))
1815 		wake_up_interruptible_all(&wq->wait);
1816 	rcu_read_unlock();
1817 }
1818 
1819 static void sock_def_error_report(struct sock *sk)
1820 {
1821 	struct socket_wq *wq;
1822 
1823 	rcu_read_lock();
1824 	wq = rcu_dereference(sk->sk_wq);
1825 	if (wq_has_sleeper(wq))
1826 		wake_up_interruptible_poll(&wq->wait, POLLERR);
1827 	sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
1828 	rcu_read_unlock();
1829 }
1830 
1831 static void sock_def_readable(struct sock *sk, int len)
1832 {
1833 	struct socket_wq *wq;
1834 
1835 	rcu_read_lock();
1836 	wq = rcu_dereference(sk->sk_wq);
1837 	if (wq_has_sleeper(wq))
1838 		wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
1839 						POLLRDNORM | POLLRDBAND);
1840 	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
1841 	rcu_read_unlock();
1842 }
1843 
1844 static void sock_def_write_space(struct sock *sk)
1845 {
1846 	struct socket_wq *wq;
1847 
1848 	rcu_read_lock();
1849 
1850 	/* Do not wake up a writer until he can make "significant"
1851 	 * progress.  --DaveM
1852 	 */
1853 	if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) {
1854 		wq = rcu_dereference(sk->sk_wq);
1855 		if (wq_has_sleeper(wq))
1856 			wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
1857 						POLLWRNORM | POLLWRBAND);
1858 
1859 		/* Should agree with poll, otherwise some programs break */
1860 		if (sock_writeable(sk))
1861 			sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
1862 	}
1863 
1864 	rcu_read_unlock();
1865 }
1866 
1867 static void sock_def_destruct(struct sock *sk)
1868 {
1869 	kfree(sk->sk_protinfo);
1870 }
1871 
1872 void sk_send_sigurg(struct sock *sk)
1873 {
1874 	if (sk->sk_socket && sk->sk_socket->file)
1875 		if (send_sigurg(&sk->sk_socket->file->f_owner))
1876 			sk_wake_async(sk, SOCK_WAKE_URG, POLL_PRI);
1877 }
1878 EXPORT_SYMBOL(sk_send_sigurg);
1879 
1880 void sk_reset_timer(struct sock *sk, struct timer_list* timer,
1881 		    unsigned long expires)
1882 {
1883 	if (!mod_timer(timer, expires))
1884 		sock_hold(sk);
1885 }
1886 EXPORT_SYMBOL(sk_reset_timer);
1887 
1888 void sk_stop_timer(struct sock *sk, struct timer_list* timer)
1889 {
1890 	if (timer_pending(timer) && del_timer(timer))
1891 		__sock_put(sk);
1892 }
1893 EXPORT_SYMBOL(sk_stop_timer);
1894 
1895 void sock_init_data(struct socket *sock, struct sock *sk)
1896 {
1897 	skb_queue_head_init(&sk->sk_receive_queue);
1898 	skb_queue_head_init(&sk->sk_write_queue);
1899 	skb_queue_head_init(&sk->sk_error_queue);
1900 #ifdef CONFIG_NET_DMA
1901 	skb_queue_head_init(&sk->sk_async_wait_queue);
1902 #endif
1903 
1904 	sk->sk_send_head	=	NULL;
1905 
1906 	init_timer(&sk->sk_timer);
1907 
1908 	sk->sk_allocation	=	GFP_KERNEL;
1909 	sk->sk_rcvbuf		=	sysctl_rmem_default;
1910 	sk->sk_sndbuf		=	sysctl_wmem_default;
1911 	sk->sk_state		=	TCP_CLOSE;
1912 	sk_set_socket(sk, sock);
1913 
1914 	sock_set_flag(sk, SOCK_ZAPPED);
1915 
1916 	if (sock) {
1917 		sk->sk_type	=	sock->type;
1918 		sk->sk_wq	=	sock->wq;
1919 		sock->sk	=	sk;
1920 	} else
1921 		sk->sk_wq	=	NULL;
1922 
1923 	spin_lock_init(&sk->sk_dst_lock);
1924 	rwlock_init(&sk->sk_callback_lock);
1925 	lockdep_set_class_and_name(&sk->sk_callback_lock,
1926 			af_callback_keys + sk->sk_family,
1927 			af_family_clock_key_strings[sk->sk_family]);
1928 
1929 	sk->sk_state_change	=	sock_def_wakeup;
1930 	sk->sk_data_ready	=	sock_def_readable;
1931 	sk->sk_write_space	=	sock_def_write_space;
1932 	sk->sk_error_report	=	sock_def_error_report;
1933 	sk->sk_destruct		=	sock_def_destruct;
1934 
1935 	sk->sk_sndmsg_page	=	NULL;
1936 	sk->sk_sndmsg_off	=	0;
1937 
1938 	sk->sk_peercred.pid 	=	0;
1939 	sk->sk_peercred.uid	=	-1;
1940 	sk->sk_peercred.gid	=	-1;
1941 	sk->sk_write_pending	=	0;
1942 	sk->sk_rcvlowat		=	1;
1943 	sk->sk_rcvtimeo		=	MAX_SCHEDULE_TIMEOUT;
1944 	sk->sk_sndtimeo		=	MAX_SCHEDULE_TIMEOUT;
1945 
1946 	sk->sk_stamp = ktime_set(-1L, 0);
1947 
1948 	/*
1949 	 * Before updating sk_refcnt, we must commit prior changes to memory
1950 	 * (Documentation/RCU/rculist_nulls.txt for details)
1951 	 */
1952 	smp_wmb();
1953 	atomic_set(&sk->sk_refcnt, 1);
1954 	atomic_set(&sk->sk_drops, 0);
1955 }
1956 EXPORT_SYMBOL(sock_init_data);
1957 
1958 void lock_sock_nested(struct sock *sk, int subclass)
1959 {
1960 	might_sleep();
1961 	spin_lock_bh(&sk->sk_lock.slock);
1962 	if (sk->sk_lock.owned)
1963 		__lock_sock(sk);
1964 	sk->sk_lock.owned = 1;
1965 	spin_unlock(&sk->sk_lock.slock);
1966 	/*
1967 	 * The sk_lock has mutex_lock() semantics here:
1968 	 */
1969 	mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_);
1970 	local_bh_enable();
1971 }
1972 EXPORT_SYMBOL(lock_sock_nested);
1973 
1974 void release_sock(struct sock *sk)
1975 {
1976 	/*
1977 	 * The sk_lock has mutex_unlock() semantics:
1978 	 */
1979 	mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
1980 
1981 	spin_lock_bh(&sk->sk_lock.slock);
1982 	if (sk->sk_backlog.tail)
1983 		__release_sock(sk);
1984 	sk->sk_lock.owned = 0;
1985 	if (waitqueue_active(&sk->sk_lock.wq))
1986 		wake_up(&sk->sk_lock.wq);
1987 	spin_unlock_bh(&sk->sk_lock.slock);
1988 }
1989 EXPORT_SYMBOL(release_sock);
1990 
1991 int sock_get_timestamp(struct sock *sk, struct timeval __user *userstamp)
1992 {
1993 	struct timeval tv;
1994 	if (!sock_flag(sk, SOCK_TIMESTAMP))
1995 		sock_enable_timestamp(sk, SOCK_TIMESTAMP);
1996 	tv = ktime_to_timeval(sk->sk_stamp);
1997 	if (tv.tv_sec == -1)
1998 		return -ENOENT;
1999 	if (tv.tv_sec == 0) {
2000 		sk->sk_stamp = ktime_get_real();
2001 		tv = ktime_to_timeval(sk->sk_stamp);
2002 	}
2003 	return copy_to_user(userstamp, &tv, sizeof(tv)) ? -EFAULT : 0;
2004 }
2005 EXPORT_SYMBOL(sock_get_timestamp);
2006 
2007 int sock_get_timestampns(struct sock *sk, struct timespec __user *userstamp)
2008 {
2009 	struct timespec ts;
2010 	if (!sock_flag(sk, SOCK_TIMESTAMP))
2011 		sock_enable_timestamp(sk, SOCK_TIMESTAMP);
2012 	ts = ktime_to_timespec(sk->sk_stamp);
2013 	if (ts.tv_sec == -1)
2014 		return -ENOENT;
2015 	if (ts.tv_sec == 0) {
2016 		sk->sk_stamp = ktime_get_real();
2017 		ts = ktime_to_timespec(sk->sk_stamp);
2018 	}
2019 	return copy_to_user(userstamp, &ts, sizeof(ts)) ? -EFAULT : 0;
2020 }
2021 EXPORT_SYMBOL(sock_get_timestampns);
2022 
2023 void sock_enable_timestamp(struct sock *sk, int flag)
2024 {
2025 	if (!sock_flag(sk, flag)) {
2026 		sock_set_flag(sk, flag);
2027 		/*
2028 		 * we just set one of the two flags which require net
2029 		 * time stamping, but time stamping might have been on
2030 		 * already because of the other one
2031 		 */
2032 		if (!sock_flag(sk,
2033 				flag == SOCK_TIMESTAMP ?
2034 				SOCK_TIMESTAMPING_RX_SOFTWARE :
2035 				SOCK_TIMESTAMP))
2036 			net_enable_timestamp();
2037 	}
2038 }
2039 
2040 /*
2041  *	Get a socket option on an socket.
2042  *
2043  *	FIX: POSIX 1003.1g is very ambiguous here. It states that
2044  *	asynchronous errors should be reported by getsockopt. We assume
2045  *	this means if you specify SO_ERROR (otherwise whats the point of it).
2046  */
2047 int sock_common_getsockopt(struct socket *sock, int level, int optname,
2048 			   char __user *optval, int __user *optlen)
2049 {
2050 	struct sock *sk = sock->sk;
2051 
2052 	return sk->sk_prot->getsockopt(sk, level, optname, optval, optlen);
2053 }
2054 EXPORT_SYMBOL(sock_common_getsockopt);
2055 
2056 #ifdef CONFIG_COMPAT
2057 int compat_sock_common_getsockopt(struct socket *sock, int level, int optname,
2058 				  char __user *optval, int __user *optlen)
2059 {
2060 	struct sock *sk = sock->sk;
2061 
2062 	if (sk->sk_prot->compat_getsockopt != NULL)
2063 		return sk->sk_prot->compat_getsockopt(sk, level, optname,
2064 						      optval, optlen);
2065 	return sk->sk_prot->getsockopt(sk, level, optname, optval, optlen);
2066 }
2067 EXPORT_SYMBOL(compat_sock_common_getsockopt);
2068 #endif
2069 
2070 int sock_common_recvmsg(struct kiocb *iocb, struct socket *sock,
2071 			struct msghdr *msg, size_t size, int flags)
2072 {
2073 	struct sock *sk = sock->sk;
2074 	int addr_len = 0;
2075 	int err;
2076 
2077 	err = sk->sk_prot->recvmsg(iocb, sk, msg, size, flags & MSG_DONTWAIT,
2078 				   flags & ~MSG_DONTWAIT, &addr_len);
2079 	if (err >= 0)
2080 		msg->msg_namelen = addr_len;
2081 	return err;
2082 }
2083 EXPORT_SYMBOL(sock_common_recvmsg);
2084 
2085 /*
2086  *	Set socket options on an inet socket.
2087  */
2088 int sock_common_setsockopt(struct socket *sock, int level, int optname,
2089 			   char __user *optval, unsigned int optlen)
2090 {
2091 	struct sock *sk = sock->sk;
2092 
2093 	return sk->sk_prot->setsockopt(sk, level, optname, optval, optlen);
2094 }
2095 EXPORT_SYMBOL(sock_common_setsockopt);
2096 
2097 #ifdef CONFIG_COMPAT
2098 int compat_sock_common_setsockopt(struct socket *sock, int level, int optname,
2099 				  char __user *optval, unsigned int optlen)
2100 {
2101 	struct sock *sk = sock->sk;
2102 
2103 	if (sk->sk_prot->compat_setsockopt != NULL)
2104 		return sk->sk_prot->compat_setsockopt(sk, level, optname,
2105 						      optval, optlen);
2106 	return sk->sk_prot->setsockopt(sk, level, optname, optval, optlen);
2107 }
2108 EXPORT_SYMBOL(compat_sock_common_setsockopt);
2109 #endif
2110 
2111 void sk_common_release(struct sock *sk)
2112 {
2113 	if (sk->sk_prot->destroy)
2114 		sk->sk_prot->destroy(sk);
2115 
2116 	/*
2117 	 * Observation: when sock_common_release is called, processes have
2118 	 * no access to socket. But net still has.
2119 	 * Step one, detach it from networking:
2120 	 *
2121 	 * A. Remove from hash tables.
2122 	 */
2123 
2124 	sk->sk_prot->unhash(sk);
2125 
2126 	/*
2127 	 * In this point socket cannot receive new packets, but it is possible
2128 	 * that some packets are in flight because some CPU runs receiver and
2129 	 * did hash table lookup before we unhashed socket. They will achieve
2130 	 * receive queue and will be purged by socket destructor.
2131 	 *
2132 	 * Also we still have packets pending on receive queue and probably,
2133 	 * our own packets waiting in device queues. sock_destroy will drain
2134 	 * receive queue, but transmitted packets will delay socket destruction
2135 	 * until the last reference will be released.
2136 	 */
2137 
2138 	sock_orphan(sk);
2139 
2140 	xfrm_sk_free_policy(sk);
2141 
2142 	sk_refcnt_debug_release(sk);
2143 	sock_put(sk);
2144 }
2145 EXPORT_SYMBOL(sk_common_release);
2146 
2147 static DEFINE_RWLOCK(proto_list_lock);
2148 static LIST_HEAD(proto_list);
2149 
2150 #ifdef CONFIG_PROC_FS
2151 #define PROTO_INUSE_NR	64	/* should be enough for the first time */
2152 struct prot_inuse {
2153 	int val[PROTO_INUSE_NR];
2154 };
2155 
2156 static DECLARE_BITMAP(proto_inuse_idx, PROTO_INUSE_NR);
2157 
2158 #ifdef CONFIG_NET_NS
2159 void sock_prot_inuse_add(struct net *net, struct proto *prot, int val)
2160 {
2161 	int cpu = smp_processor_id();
2162 	per_cpu_ptr(net->core.inuse, cpu)->val[prot->inuse_idx] += val;
2163 }
2164 EXPORT_SYMBOL_GPL(sock_prot_inuse_add);
2165 
2166 int sock_prot_inuse_get(struct net *net, struct proto *prot)
2167 {
2168 	int cpu, idx = prot->inuse_idx;
2169 	int res = 0;
2170 
2171 	for_each_possible_cpu(cpu)
2172 		res += per_cpu_ptr(net->core.inuse, cpu)->val[idx];
2173 
2174 	return res >= 0 ? res : 0;
2175 }
2176 EXPORT_SYMBOL_GPL(sock_prot_inuse_get);
2177 
2178 static int __net_init sock_inuse_init_net(struct net *net)
2179 {
2180 	net->core.inuse = alloc_percpu(struct prot_inuse);
2181 	return net->core.inuse ? 0 : -ENOMEM;
2182 }
2183 
2184 static void __net_exit sock_inuse_exit_net(struct net *net)
2185 {
2186 	free_percpu(net->core.inuse);
2187 }
2188 
2189 static struct pernet_operations net_inuse_ops = {
2190 	.init = sock_inuse_init_net,
2191 	.exit = sock_inuse_exit_net,
2192 };
2193 
2194 static __init int net_inuse_init(void)
2195 {
2196 	if (register_pernet_subsys(&net_inuse_ops))
2197 		panic("Cannot initialize net inuse counters");
2198 
2199 	return 0;
2200 }
2201 
2202 core_initcall(net_inuse_init);
2203 #else
2204 static DEFINE_PER_CPU(struct prot_inuse, prot_inuse);
2205 
2206 void sock_prot_inuse_add(struct net *net, struct proto *prot, int val)
2207 {
2208 	__get_cpu_var(prot_inuse).val[prot->inuse_idx] += val;
2209 }
2210 EXPORT_SYMBOL_GPL(sock_prot_inuse_add);
2211 
2212 int sock_prot_inuse_get(struct net *net, struct proto *prot)
2213 {
2214 	int cpu, idx = prot->inuse_idx;
2215 	int res = 0;
2216 
2217 	for_each_possible_cpu(cpu)
2218 		res += per_cpu(prot_inuse, cpu).val[idx];
2219 
2220 	return res >= 0 ? res : 0;
2221 }
2222 EXPORT_SYMBOL_GPL(sock_prot_inuse_get);
2223 #endif
2224 
2225 static void assign_proto_idx(struct proto *prot)
2226 {
2227 	prot->inuse_idx = find_first_zero_bit(proto_inuse_idx, PROTO_INUSE_NR);
2228 
2229 	if (unlikely(prot->inuse_idx == PROTO_INUSE_NR - 1)) {
2230 		printk(KERN_ERR "PROTO_INUSE_NR exhausted\n");
2231 		return;
2232 	}
2233 
2234 	set_bit(prot->inuse_idx, proto_inuse_idx);
2235 }
2236 
2237 static void release_proto_idx(struct proto *prot)
2238 {
2239 	if (prot->inuse_idx != PROTO_INUSE_NR - 1)
2240 		clear_bit(prot->inuse_idx, proto_inuse_idx);
2241 }
2242 #else
2243 static inline void assign_proto_idx(struct proto *prot)
2244 {
2245 }
2246 
2247 static inline void release_proto_idx(struct proto *prot)
2248 {
2249 }
2250 #endif
2251 
2252 int proto_register(struct proto *prot, int alloc_slab)
2253 {
2254 	if (alloc_slab) {
2255 		prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0,
2256 					SLAB_HWCACHE_ALIGN | prot->slab_flags,
2257 					NULL);
2258 
2259 		if (prot->slab == NULL) {
2260 			printk(KERN_CRIT "%s: Can't create sock SLAB cache!\n",
2261 			       prot->name);
2262 			goto out;
2263 		}
2264 
2265 		if (prot->rsk_prot != NULL) {
2266 			prot->rsk_prot->slab_name = kasprintf(GFP_KERNEL, "request_sock_%s", prot->name);
2267 			if (prot->rsk_prot->slab_name == NULL)
2268 				goto out_free_sock_slab;
2269 
2270 			prot->rsk_prot->slab = kmem_cache_create(prot->rsk_prot->slab_name,
2271 								 prot->rsk_prot->obj_size, 0,
2272 								 SLAB_HWCACHE_ALIGN, NULL);
2273 
2274 			if (prot->rsk_prot->slab == NULL) {
2275 				printk(KERN_CRIT "%s: Can't create request sock SLAB cache!\n",
2276 				       prot->name);
2277 				goto out_free_request_sock_slab_name;
2278 			}
2279 		}
2280 
2281 		if (prot->twsk_prot != NULL) {
2282 			prot->twsk_prot->twsk_slab_name = kasprintf(GFP_KERNEL, "tw_sock_%s", prot->name);
2283 
2284 			if (prot->twsk_prot->twsk_slab_name == NULL)
2285 				goto out_free_request_sock_slab;
2286 
2287 			prot->twsk_prot->twsk_slab =
2288 				kmem_cache_create(prot->twsk_prot->twsk_slab_name,
2289 						  prot->twsk_prot->twsk_obj_size,
2290 						  0,
2291 						  SLAB_HWCACHE_ALIGN |
2292 							prot->slab_flags,
2293 						  NULL);
2294 			if (prot->twsk_prot->twsk_slab == NULL)
2295 				goto out_free_timewait_sock_slab_name;
2296 		}
2297 	}
2298 
2299 	write_lock(&proto_list_lock);
2300 	list_add(&prot->node, &proto_list);
2301 	assign_proto_idx(prot);
2302 	write_unlock(&proto_list_lock);
2303 	return 0;
2304 
2305 out_free_timewait_sock_slab_name:
2306 	kfree(prot->twsk_prot->twsk_slab_name);
2307 out_free_request_sock_slab:
2308 	if (prot->rsk_prot && prot->rsk_prot->slab) {
2309 		kmem_cache_destroy(prot->rsk_prot->slab);
2310 		prot->rsk_prot->slab = NULL;
2311 	}
2312 out_free_request_sock_slab_name:
2313 	if (prot->rsk_prot)
2314 		kfree(prot->rsk_prot->slab_name);
2315 out_free_sock_slab:
2316 	kmem_cache_destroy(prot->slab);
2317 	prot->slab = NULL;
2318 out:
2319 	return -ENOBUFS;
2320 }
2321 EXPORT_SYMBOL(proto_register);
2322 
2323 void proto_unregister(struct proto *prot)
2324 {
2325 	write_lock(&proto_list_lock);
2326 	release_proto_idx(prot);
2327 	list_del(&prot->node);
2328 	write_unlock(&proto_list_lock);
2329 
2330 	if (prot->slab != NULL) {
2331 		kmem_cache_destroy(prot->slab);
2332 		prot->slab = NULL;
2333 	}
2334 
2335 	if (prot->rsk_prot != NULL && prot->rsk_prot->slab != NULL) {
2336 		kmem_cache_destroy(prot->rsk_prot->slab);
2337 		kfree(prot->rsk_prot->slab_name);
2338 		prot->rsk_prot->slab = NULL;
2339 	}
2340 
2341 	if (prot->twsk_prot != NULL && prot->twsk_prot->twsk_slab != NULL) {
2342 		kmem_cache_destroy(prot->twsk_prot->twsk_slab);
2343 		kfree(prot->twsk_prot->twsk_slab_name);
2344 		prot->twsk_prot->twsk_slab = NULL;
2345 	}
2346 }
2347 EXPORT_SYMBOL(proto_unregister);
2348 
2349 #ifdef CONFIG_PROC_FS
2350 static void *proto_seq_start(struct seq_file *seq, loff_t *pos)
2351 	__acquires(proto_list_lock)
2352 {
2353 	read_lock(&proto_list_lock);
2354 	return seq_list_start_head(&proto_list, *pos);
2355 }
2356 
2357 static void *proto_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2358 {
2359 	return seq_list_next(v, &proto_list, pos);
2360 }
2361 
2362 static void proto_seq_stop(struct seq_file *seq, void *v)
2363 	__releases(proto_list_lock)
2364 {
2365 	read_unlock(&proto_list_lock);
2366 }
2367 
2368 static char proto_method_implemented(const void *method)
2369 {
2370 	return method == NULL ? 'n' : 'y';
2371 }
2372 
2373 static void proto_seq_printf(struct seq_file *seq, struct proto *proto)
2374 {
2375 	seq_printf(seq, "%-9s %4u %6d  %6d   %-3s %6u   %-3s  %-10s "
2376 			"%2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c %2c\n",
2377 		   proto->name,
2378 		   proto->obj_size,
2379 		   sock_prot_inuse_get(seq_file_net(seq), proto),
2380 		   proto->memory_allocated != NULL ? atomic_read(proto->memory_allocated) : -1,
2381 		   proto->memory_pressure != NULL ? *proto->memory_pressure ? "yes" : "no" : "NI",
2382 		   proto->max_header,
2383 		   proto->slab == NULL ? "no" : "yes",
2384 		   module_name(proto->owner),
2385 		   proto_method_implemented(proto->close),
2386 		   proto_method_implemented(proto->connect),
2387 		   proto_method_implemented(proto->disconnect),
2388 		   proto_method_implemented(proto->accept),
2389 		   proto_method_implemented(proto->ioctl),
2390 		   proto_method_implemented(proto->init),
2391 		   proto_method_implemented(proto->destroy),
2392 		   proto_method_implemented(proto->shutdown),
2393 		   proto_method_implemented(proto->setsockopt),
2394 		   proto_method_implemented(proto->getsockopt),
2395 		   proto_method_implemented(proto->sendmsg),
2396 		   proto_method_implemented(proto->recvmsg),
2397 		   proto_method_implemented(proto->sendpage),
2398 		   proto_method_implemented(proto->bind),
2399 		   proto_method_implemented(proto->backlog_rcv),
2400 		   proto_method_implemented(proto->hash),
2401 		   proto_method_implemented(proto->unhash),
2402 		   proto_method_implemented(proto->get_port),
2403 		   proto_method_implemented(proto->enter_memory_pressure));
2404 }
2405 
2406 static int proto_seq_show(struct seq_file *seq, void *v)
2407 {
2408 	if (v == &proto_list)
2409 		seq_printf(seq, "%-9s %-4s %-8s %-6s %-5s %-7s %-4s %-10s %s",
2410 			   "protocol",
2411 			   "size",
2412 			   "sockets",
2413 			   "memory",
2414 			   "press",
2415 			   "maxhdr",
2416 			   "slab",
2417 			   "module",
2418 			   "cl co di ac io in de sh ss gs se re sp bi br ha uh gp em\n");
2419 	else
2420 		proto_seq_printf(seq, list_entry(v, struct proto, node));
2421 	return 0;
2422 }
2423 
2424 static const struct seq_operations proto_seq_ops = {
2425 	.start  = proto_seq_start,
2426 	.next   = proto_seq_next,
2427 	.stop   = proto_seq_stop,
2428 	.show   = proto_seq_show,
2429 };
2430 
2431 static int proto_seq_open(struct inode *inode, struct file *file)
2432 {
2433 	return seq_open_net(inode, file, &proto_seq_ops,
2434 			    sizeof(struct seq_net_private));
2435 }
2436 
2437 static const struct file_operations proto_seq_fops = {
2438 	.owner		= THIS_MODULE,
2439 	.open		= proto_seq_open,
2440 	.read		= seq_read,
2441 	.llseek		= seq_lseek,
2442 	.release	= seq_release_net,
2443 };
2444 
2445 static __net_init int proto_init_net(struct net *net)
2446 {
2447 	if (!proc_net_fops_create(net, "protocols", S_IRUGO, &proto_seq_fops))
2448 		return -ENOMEM;
2449 
2450 	return 0;
2451 }
2452 
2453 static __net_exit void proto_exit_net(struct net *net)
2454 {
2455 	proc_net_remove(net, "protocols");
2456 }
2457 
2458 
2459 static __net_initdata struct pernet_operations proto_net_ops = {
2460 	.init = proto_init_net,
2461 	.exit = proto_exit_net,
2462 };
2463 
2464 static int __init proto_init(void)
2465 {
2466 	return register_pernet_subsys(&proto_net_ops);
2467 }
2468 
2469 subsys_initcall(proto_init);
2470 
2471 #endif /* PROC_FS */
2472