xref: /openbmc/linux/net/kcm/kcmsock.c (revision 44ecda71)
1  // SPDX-License-Identifier: GPL-2.0-only
2  /*
3   * Kernel Connection Multiplexor
4   *
5   * Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
6   */
7  
8  #include <linux/bpf.h>
9  #include <linux/errno.h>
10  #include <linux/errqueue.h>
11  #include <linux/file.h>
12  #include <linux/filter.h>
13  #include <linux/in.h>
14  #include <linux/kernel.h>
15  #include <linux/module.h>
16  #include <linux/net.h>
17  #include <linux/netdevice.h>
18  #include <linux/poll.h>
19  #include <linux/rculist.h>
20  #include <linux/skbuff.h>
21  #include <linux/socket.h>
22  #include <linux/uaccess.h>
23  #include <linux/workqueue.h>
24  #include <linux/syscalls.h>
25  #include <linux/sched/signal.h>
26  
27  #include <net/kcm.h>
28  #include <net/netns/generic.h>
29  #include <net/sock.h>
30  #include <uapi/linux/kcm.h>
31  
32  unsigned int kcm_net_id;
33  
34  static struct kmem_cache *kcm_psockp __read_mostly;
35  static struct kmem_cache *kcm_muxp __read_mostly;
36  static struct workqueue_struct *kcm_wq;
37  
38  static inline struct kcm_sock *kcm_sk(const struct sock *sk)
39  {
40  	return (struct kcm_sock *)sk;
41  }
42  
43  static inline struct kcm_tx_msg *kcm_tx_msg(struct sk_buff *skb)
44  {
45  	return (struct kcm_tx_msg *)skb->cb;
46  }
47  
48  static void report_csk_error(struct sock *csk, int err)
49  {
50  	csk->sk_err = EPIPE;
51  	sk_error_report(csk);
52  }
53  
54  static void kcm_abort_tx_psock(struct kcm_psock *psock, int err,
55  			       bool wakeup_kcm)
56  {
57  	struct sock *csk = psock->sk;
58  	struct kcm_mux *mux = psock->mux;
59  
60  	/* Unrecoverable error in transmit */
61  
62  	spin_lock_bh(&mux->lock);
63  
64  	if (psock->tx_stopped) {
65  		spin_unlock_bh(&mux->lock);
66  		return;
67  	}
68  
69  	psock->tx_stopped = 1;
70  	KCM_STATS_INCR(psock->stats.tx_aborts);
71  
72  	if (!psock->tx_kcm) {
73  		/* Take off psocks_avail list */
74  		list_del(&psock->psock_avail_list);
75  	} else if (wakeup_kcm) {
76  		/* In this case psock is being aborted while outside of
77  		 * write_msgs and psock is reserved. Schedule tx_work
78  		 * to handle the failure there. Need to commit tx_stopped
79  		 * before queuing work.
80  		 */
81  		smp_mb();
82  
83  		queue_work(kcm_wq, &psock->tx_kcm->tx_work);
84  	}
85  
86  	spin_unlock_bh(&mux->lock);
87  
88  	/* Report error on lower socket */
89  	report_csk_error(csk, err);
90  }
91  
92  /* RX mux lock held. */
93  static void kcm_update_rx_mux_stats(struct kcm_mux *mux,
94  				    struct kcm_psock *psock)
95  {
96  	STRP_STATS_ADD(mux->stats.rx_bytes,
97  		       psock->strp.stats.bytes -
98  		       psock->saved_rx_bytes);
99  	mux->stats.rx_msgs +=
100  		psock->strp.stats.msgs - psock->saved_rx_msgs;
101  	psock->saved_rx_msgs = psock->strp.stats.msgs;
102  	psock->saved_rx_bytes = psock->strp.stats.bytes;
103  }
104  
105  static void kcm_update_tx_mux_stats(struct kcm_mux *mux,
106  				    struct kcm_psock *psock)
107  {
108  	KCM_STATS_ADD(mux->stats.tx_bytes,
109  		      psock->stats.tx_bytes - psock->saved_tx_bytes);
110  	mux->stats.tx_msgs +=
111  		psock->stats.tx_msgs - psock->saved_tx_msgs;
112  	psock->saved_tx_msgs = psock->stats.tx_msgs;
113  	psock->saved_tx_bytes = psock->stats.tx_bytes;
114  }
115  
116  static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
117  
118  /* KCM is ready to receive messages on its queue-- either the KCM is new or
119   * has become unblocked after being blocked on full socket buffer. Queue any
120   * pending ready messages on a psock. RX mux lock held.
121   */
122  static void kcm_rcv_ready(struct kcm_sock *kcm)
123  {
124  	struct kcm_mux *mux = kcm->mux;
125  	struct kcm_psock *psock;
126  	struct sk_buff *skb;
127  
128  	if (unlikely(kcm->rx_wait || kcm->rx_psock || kcm->rx_disabled))
129  		return;
130  
131  	while (unlikely((skb = __skb_dequeue(&mux->rx_hold_queue)))) {
132  		if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
133  			/* Assuming buffer limit has been reached */
134  			skb_queue_head(&mux->rx_hold_queue, skb);
135  			WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
136  			return;
137  		}
138  	}
139  
140  	while (!list_empty(&mux->psocks_ready)) {
141  		psock = list_first_entry(&mux->psocks_ready, struct kcm_psock,
142  					 psock_ready_list);
143  
144  		if (kcm_queue_rcv_skb(&kcm->sk, psock->ready_rx_msg)) {
145  			/* Assuming buffer limit has been reached */
146  			WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
147  			return;
148  		}
149  
150  		/* Consumed the ready message on the psock. Schedule rx_work to
151  		 * get more messages.
152  		 */
153  		list_del(&psock->psock_ready_list);
154  		psock->ready_rx_msg = NULL;
155  		/* Commit clearing of ready_rx_msg for queuing work */
156  		smp_mb();
157  
158  		strp_unpause(&psock->strp);
159  		strp_check_rcv(&psock->strp);
160  	}
161  
162  	/* Buffer limit is okay now, add to ready list */
163  	list_add_tail(&kcm->wait_rx_list,
164  		      &kcm->mux->kcm_rx_waiters);
165  	/* paired with lockless reads in kcm_rfree() */
166  	WRITE_ONCE(kcm->rx_wait, true);
167  }
168  
169  static void kcm_rfree(struct sk_buff *skb)
170  {
171  	struct sock *sk = skb->sk;
172  	struct kcm_sock *kcm = kcm_sk(sk);
173  	struct kcm_mux *mux = kcm->mux;
174  	unsigned int len = skb->truesize;
175  
176  	sk_mem_uncharge(sk, len);
177  	atomic_sub(len, &sk->sk_rmem_alloc);
178  
179  	/* For reading rx_wait and rx_psock without holding lock */
180  	smp_mb__after_atomic();
181  
182  	if (!READ_ONCE(kcm->rx_wait) && !READ_ONCE(kcm->rx_psock) &&
183  	    sk_rmem_alloc_get(sk) < sk->sk_rcvlowat) {
184  		spin_lock_bh(&mux->rx_lock);
185  		kcm_rcv_ready(kcm);
186  		spin_unlock_bh(&mux->rx_lock);
187  	}
188  }
189  
190  static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
191  {
192  	struct sk_buff_head *list = &sk->sk_receive_queue;
193  
194  	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
195  		return -ENOMEM;
196  
197  	if (!sk_rmem_schedule(sk, skb, skb->truesize))
198  		return -ENOBUFS;
199  
200  	skb->dev = NULL;
201  
202  	skb_orphan(skb);
203  	skb->sk = sk;
204  	skb->destructor = kcm_rfree;
205  	atomic_add(skb->truesize, &sk->sk_rmem_alloc);
206  	sk_mem_charge(sk, skb->truesize);
207  
208  	skb_queue_tail(list, skb);
209  
210  	if (!sock_flag(sk, SOCK_DEAD))
211  		sk->sk_data_ready(sk);
212  
213  	return 0;
214  }
215  
216  /* Requeue received messages for a kcm socket to other kcm sockets. This is
217   * called with a kcm socket is receive disabled.
218   * RX mux lock held.
219   */
220  static void requeue_rx_msgs(struct kcm_mux *mux, struct sk_buff_head *head)
221  {
222  	struct sk_buff *skb;
223  	struct kcm_sock *kcm;
224  
225  	while ((skb = __skb_dequeue(head))) {
226  		/* Reset destructor to avoid calling kcm_rcv_ready */
227  		skb->destructor = sock_rfree;
228  		skb_orphan(skb);
229  try_again:
230  		if (list_empty(&mux->kcm_rx_waiters)) {
231  			skb_queue_tail(&mux->rx_hold_queue, skb);
232  			continue;
233  		}
234  
235  		kcm = list_first_entry(&mux->kcm_rx_waiters,
236  				       struct kcm_sock, wait_rx_list);
237  
238  		if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
239  			/* Should mean socket buffer full */
240  			list_del(&kcm->wait_rx_list);
241  			/* paired with lockless reads in kcm_rfree() */
242  			WRITE_ONCE(kcm->rx_wait, false);
243  
244  			/* Commit rx_wait to read in kcm_free */
245  			smp_wmb();
246  
247  			goto try_again;
248  		}
249  	}
250  }
251  
252  /* Lower sock lock held */
253  static struct kcm_sock *reserve_rx_kcm(struct kcm_psock *psock,
254  				       struct sk_buff *head)
255  {
256  	struct kcm_mux *mux = psock->mux;
257  	struct kcm_sock *kcm;
258  
259  	WARN_ON(psock->ready_rx_msg);
260  
261  	if (psock->rx_kcm)
262  		return psock->rx_kcm;
263  
264  	spin_lock_bh(&mux->rx_lock);
265  
266  	if (psock->rx_kcm) {
267  		spin_unlock_bh(&mux->rx_lock);
268  		return psock->rx_kcm;
269  	}
270  
271  	kcm_update_rx_mux_stats(mux, psock);
272  
273  	if (list_empty(&mux->kcm_rx_waiters)) {
274  		psock->ready_rx_msg = head;
275  		strp_pause(&psock->strp);
276  		list_add_tail(&psock->psock_ready_list,
277  			      &mux->psocks_ready);
278  		spin_unlock_bh(&mux->rx_lock);
279  		return NULL;
280  	}
281  
282  	kcm = list_first_entry(&mux->kcm_rx_waiters,
283  			       struct kcm_sock, wait_rx_list);
284  	list_del(&kcm->wait_rx_list);
285  	/* paired with lockless reads in kcm_rfree() */
286  	WRITE_ONCE(kcm->rx_wait, false);
287  
288  	psock->rx_kcm = kcm;
289  	/* paired with lockless reads in kcm_rfree() */
290  	WRITE_ONCE(kcm->rx_psock, psock);
291  
292  	spin_unlock_bh(&mux->rx_lock);
293  
294  	return kcm;
295  }
296  
297  static void kcm_done(struct kcm_sock *kcm);
298  
299  static void kcm_done_work(struct work_struct *w)
300  {
301  	kcm_done(container_of(w, struct kcm_sock, done_work));
302  }
303  
304  /* Lower sock held */
305  static void unreserve_rx_kcm(struct kcm_psock *psock,
306  			     bool rcv_ready)
307  {
308  	struct kcm_sock *kcm = psock->rx_kcm;
309  	struct kcm_mux *mux = psock->mux;
310  
311  	if (!kcm)
312  		return;
313  
314  	spin_lock_bh(&mux->rx_lock);
315  
316  	psock->rx_kcm = NULL;
317  	/* paired with lockless reads in kcm_rfree() */
318  	WRITE_ONCE(kcm->rx_psock, NULL);
319  
320  	/* Commit kcm->rx_psock before sk_rmem_alloc_get to sync with
321  	 * kcm_rfree
322  	 */
323  	smp_mb();
324  
325  	if (unlikely(kcm->done)) {
326  		spin_unlock_bh(&mux->rx_lock);
327  
328  		/* Need to run kcm_done in a task since we need to qcquire
329  		 * callback locks which may already be held here.
330  		 */
331  		INIT_WORK(&kcm->done_work, kcm_done_work);
332  		schedule_work(&kcm->done_work);
333  		return;
334  	}
335  
336  	if (unlikely(kcm->rx_disabled)) {
337  		requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
338  	} else if (rcv_ready || unlikely(!sk_rmem_alloc_get(&kcm->sk))) {
339  		/* Check for degenerative race with rx_wait that all
340  		 * data was dequeued (accounted for in kcm_rfree).
341  		 */
342  		kcm_rcv_ready(kcm);
343  	}
344  	spin_unlock_bh(&mux->rx_lock);
345  }
346  
347  /* Lower sock lock held */
348  static void psock_data_ready(struct sock *sk)
349  {
350  	struct kcm_psock *psock;
351  
352  	read_lock_bh(&sk->sk_callback_lock);
353  
354  	psock = (struct kcm_psock *)sk->sk_user_data;
355  	if (likely(psock))
356  		strp_data_ready(&psock->strp);
357  
358  	read_unlock_bh(&sk->sk_callback_lock);
359  }
360  
361  /* Called with lower sock held */
362  static void kcm_rcv_strparser(struct strparser *strp, struct sk_buff *skb)
363  {
364  	struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
365  	struct kcm_sock *kcm;
366  
367  try_queue:
368  	kcm = reserve_rx_kcm(psock, skb);
369  	if (!kcm) {
370  		 /* Unable to reserve a KCM, message is held in psock and strp
371  		  * is paused.
372  		  */
373  		return;
374  	}
375  
376  	if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
377  		/* Should mean socket buffer full */
378  		unreserve_rx_kcm(psock, false);
379  		goto try_queue;
380  	}
381  }
382  
383  static int kcm_parse_func_strparser(struct strparser *strp, struct sk_buff *skb)
384  {
385  	struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
386  	struct bpf_prog *prog = psock->bpf_prog;
387  	int res;
388  
389  	res = bpf_prog_run_pin_on_cpu(prog, skb);
390  	return res;
391  }
392  
393  static int kcm_read_sock_done(struct strparser *strp, int err)
394  {
395  	struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp);
396  
397  	unreserve_rx_kcm(psock, true);
398  
399  	return err;
400  }
401  
402  static void psock_state_change(struct sock *sk)
403  {
404  	/* TCP only does a EPOLLIN for a half close. Do a EPOLLHUP here
405  	 * since application will normally not poll with EPOLLIN
406  	 * on the TCP sockets.
407  	 */
408  
409  	report_csk_error(sk, EPIPE);
410  }
411  
412  static void psock_write_space(struct sock *sk)
413  {
414  	struct kcm_psock *psock;
415  	struct kcm_mux *mux;
416  	struct kcm_sock *kcm;
417  
418  	read_lock_bh(&sk->sk_callback_lock);
419  
420  	psock = (struct kcm_psock *)sk->sk_user_data;
421  	if (unlikely(!psock))
422  		goto out;
423  	mux = psock->mux;
424  
425  	spin_lock_bh(&mux->lock);
426  
427  	/* Check if the socket is reserved so someone is waiting for sending. */
428  	kcm = psock->tx_kcm;
429  	if (kcm && !unlikely(kcm->tx_stopped))
430  		queue_work(kcm_wq, &kcm->tx_work);
431  
432  	spin_unlock_bh(&mux->lock);
433  out:
434  	read_unlock_bh(&sk->sk_callback_lock);
435  }
436  
437  static void unreserve_psock(struct kcm_sock *kcm);
438  
439  /* kcm sock is locked. */
440  static struct kcm_psock *reserve_psock(struct kcm_sock *kcm)
441  {
442  	struct kcm_mux *mux = kcm->mux;
443  	struct kcm_psock *psock;
444  
445  	psock = kcm->tx_psock;
446  
447  	smp_rmb(); /* Must read tx_psock before tx_wait */
448  
449  	if (psock) {
450  		WARN_ON(kcm->tx_wait);
451  		if (unlikely(psock->tx_stopped))
452  			unreserve_psock(kcm);
453  		else
454  			return kcm->tx_psock;
455  	}
456  
457  	spin_lock_bh(&mux->lock);
458  
459  	/* Check again under lock to see if psock was reserved for this
460  	 * psock via psock_unreserve.
461  	 */
462  	psock = kcm->tx_psock;
463  	if (unlikely(psock)) {
464  		WARN_ON(kcm->tx_wait);
465  		spin_unlock_bh(&mux->lock);
466  		return kcm->tx_psock;
467  	}
468  
469  	if (!list_empty(&mux->psocks_avail)) {
470  		psock = list_first_entry(&mux->psocks_avail,
471  					 struct kcm_psock,
472  					 psock_avail_list);
473  		list_del(&psock->psock_avail_list);
474  		if (kcm->tx_wait) {
475  			list_del(&kcm->wait_psock_list);
476  			kcm->tx_wait = false;
477  		}
478  		kcm->tx_psock = psock;
479  		psock->tx_kcm = kcm;
480  		KCM_STATS_INCR(psock->stats.reserved);
481  	} else if (!kcm->tx_wait) {
482  		list_add_tail(&kcm->wait_psock_list,
483  			      &mux->kcm_tx_waiters);
484  		kcm->tx_wait = true;
485  	}
486  
487  	spin_unlock_bh(&mux->lock);
488  
489  	return psock;
490  }
491  
492  /* mux lock held */
493  static void psock_now_avail(struct kcm_psock *psock)
494  {
495  	struct kcm_mux *mux = psock->mux;
496  	struct kcm_sock *kcm;
497  
498  	if (list_empty(&mux->kcm_tx_waiters)) {
499  		list_add_tail(&psock->psock_avail_list,
500  			      &mux->psocks_avail);
501  	} else {
502  		kcm = list_first_entry(&mux->kcm_tx_waiters,
503  				       struct kcm_sock,
504  				       wait_psock_list);
505  		list_del(&kcm->wait_psock_list);
506  		kcm->tx_wait = false;
507  		psock->tx_kcm = kcm;
508  
509  		/* Commit before changing tx_psock since that is read in
510  		 * reserve_psock before queuing work.
511  		 */
512  		smp_mb();
513  
514  		kcm->tx_psock = psock;
515  		KCM_STATS_INCR(psock->stats.reserved);
516  		queue_work(kcm_wq, &kcm->tx_work);
517  	}
518  }
519  
520  /* kcm sock is locked. */
521  static void unreserve_psock(struct kcm_sock *kcm)
522  {
523  	struct kcm_psock *psock;
524  	struct kcm_mux *mux = kcm->mux;
525  
526  	spin_lock_bh(&mux->lock);
527  
528  	psock = kcm->tx_psock;
529  
530  	if (WARN_ON(!psock)) {
531  		spin_unlock_bh(&mux->lock);
532  		return;
533  	}
534  
535  	smp_rmb(); /* Read tx_psock before tx_wait */
536  
537  	kcm_update_tx_mux_stats(mux, psock);
538  
539  	WARN_ON(kcm->tx_wait);
540  
541  	kcm->tx_psock = NULL;
542  	psock->tx_kcm = NULL;
543  	KCM_STATS_INCR(psock->stats.unreserved);
544  
545  	if (unlikely(psock->tx_stopped)) {
546  		if (psock->done) {
547  			/* Deferred free */
548  			list_del(&psock->psock_list);
549  			mux->psocks_cnt--;
550  			sock_put(psock->sk);
551  			fput(psock->sk->sk_socket->file);
552  			kmem_cache_free(kcm_psockp, psock);
553  		}
554  
555  		/* Don't put back on available list */
556  
557  		spin_unlock_bh(&mux->lock);
558  
559  		return;
560  	}
561  
562  	psock_now_avail(psock);
563  
564  	spin_unlock_bh(&mux->lock);
565  }
566  
567  static void kcm_report_tx_retry(struct kcm_sock *kcm)
568  {
569  	struct kcm_mux *mux = kcm->mux;
570  
571  	spin_lock_bh(&mux->lock);
572  	KCM_STATS_INCR(mux->stats.tx_retries);
573  	spin_unlock_bh(&mux->lock);
574  }
575  
576  /* Write any messages ready on the kcm socket.  Called with kcm sock lock
577   * held.  Return bytes actually sent or error.
578   */
579  static int kcm_write_msgs(struct kcm_sock *kcm)
580  {
581  	struct sock *sk = &kcm->sk;
582  	struct kcm_psock *psock;
583  	struct sk_buff *skb, *head;
584  	struct kcm_tx_msg *txm;
585  	unsigned short fragidx, frag_offset;
586  	unsigned int sent, total_sent = 0;
587  	int ret = 0;
588  
589  	kcm->tx_wait_more = false;
590  	psock = kcm->tx_psock;
591  	if (unlikely(psock && psock->tx_stopped)) {
592  		/* A reserved psock was aborted asynchronously. Unreserve
593  		 * it and we'll retry the message.
594  		 */
595  		unreserve_psock(kcm);
596  		kcm_report_tx_retry(kcm);
597  		if (skb_queue_empty(&sk->sk_write_queue))
598  			return 0;
599  
600  		kcm_tx_msg(skb_peek(&sk->sk_write_queue))->sent = 0;
601  
602  	} else if (skb_queue_empty(&sk->sk_write_queue)) {
603  		return 0;
604  	}
605  
606  	head = skb_peek(&sk->sk_write_queue);
607  	txm = kcm_tx_msg(head);
608  
609  	if (txm->sent) {
610  		/* Send of first skbuff in queue already in progress */
611  		if (WARN_ON(!psock)) {
612  			ret = -EINVAL;
613  			goto out;
614  		}
615  		sent = txm->sent;
616  		frag_offset = txm->frag_offset;
617  		fragidx = txm->fragidx;
618  		skb = txm->frag_skb;
619  
620  		goto do_frag;
621  	}
622  
623  try_again:
624  	psock = reserve_psock(kcm);
625  	if (!psock)
626  		goto out;
627  
628  	do {
629  		skb = head;
630  		txm = kcm_tx_msg(head);
631  		sent = 0;
632  
633  do_frag_list:
634  		if (WARN_ON(!skb_shinfo(skb)->nr_frags)) {
635  			ret = -EINVAL;
636  			goto out;
637  		}
638  
639  		for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags;
640  		     fragidx++) {
641  			skb_frag_t *frag;
642  
643  			frag_offset = 0;
644  do_frag:
645  			frag = &skb_shinfo(skb)->frags[fragidx];
646  			if (WARN_ON(!skb_frag_size(frag))) {
647  				ret = -EINVAL;
648  				goto out;
649  			}
650  
651  			ret = kernel_sendpage(psock->sk->sk_socket,
652  					      skb_frag_page(frag),
653  					      skb_frag_off(frag) + frag_offset,
654  					      skb_frag_size(frag) - frag_offset,
655  					      MSG_DONTWAIT);
656  			if (ret <= 0) {
657  				if (ret == -EAGAIN) {
658  					/* Save state to try again when there's
659  					 * write space on the socket
660  					 */
661  					txm->sent = sent;
662  					txm->frag_offset = frag_offset;
663  					txm->fragidx = fragidx;
664  					txm->frag_skb = skb;
665  
666  					ret = 0;
667  					goto out;
668  				}
669  
670  				/* Hard failure in sending message, abort this
671  				 * psock since it has lost framing
672  				 * synchronization and retry sending the
673  				 * message from the beginning.
674  				 */
675  				kcm_abort_tx_psock(psock, ret ? -ret : EPIPE,
676  						   true);
677  				unreserve_psock(kcm);
678  
679  				txm->sent = 0;
680  				kcm_report_tx_retry(kcm);
681  				ret = 0;
682  
683  				goto try_again;
684  			}
685  
686  			sent += ret;
687  			frag_offset += ret;
688  			KCM_STATS_ADD(psock->stats.tx_bytes, ret);
689  			if (frag_offset < skb_frag_size(frag)) {
690  				/* Not finished with this frag */
691  				goto do_frag;
692  			}
693  		}
694  
695  		if (skb == head) {
696  			if (skb_has_frag_list(skb)) {
697  				skb = skb_shinfo(skb)->frag_list;
698  				goto do_frag_list;
699  			}
700  		} else if (skb->next) {
701  			skb = skb->next;
702  			goto do_frag_list;
703  		}
704  
705  		/* Successfully sent the whole packet, account for it. */
706  		skb_dequeue(&sk->sk_write_queue);
707  		kfree_skb(head);
708  		sk->sk_wmem_queued -= sent;
709  		total_sent += sent;
710  		KCM_STATS_INCR(psock->stats.tx_msgs);
711  	} while ((head = skb_peek(&sk->sk_write_queue)));
712  out:
713  	if (!head) {
714  		/* Done with all queued messages. */
715  		WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
716  		unreserve_psock(kcm);
717  	}
718  
719  	/* Check if write space is available */
720  	sk->sk_write_space(sk);
721  
722  	return total_sent ? : ret;
723  }
724  
725  static void kcm_tx_work(struct work_struct *w)
726  {
727  	struct kcm_sock *kcm = container_of(w, struct kcm_sock, tx_work);
728  	struct sock *sk = &kcm->sk;
729  	int err;
730  
731  	lock_sock(sk);
732  
733  	/* Primarily for SOCK_DGRAM sockets, also handle asynchronous tx
734  	 * aborts
735  	 */
736  	err = kcm_write_msgs(kcm);
737  	if (err < 0) {
738  		/* Hard failure in write, report error on KCM socket */
739  		pr_warn("KCM: Hard failure on kcm_write_msgs %d\n", err);
740  		report_csk_error(&kcm->sk, -err);
741  		goto out;
742  	}
743  
744  	/* Primarily for SOCK_SEQPACKET sockets */
745  	if (likely(sk->sk_socket) &&
746  	    test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
747  		clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
748  		sk->sk_write_space(sk);
749  	}
750  
751  out:
752  	release_sock(sk);
753  }
754  
755  static void kcm_push(struct kcm_sock *kcm)
756  {
757  	if (kcm->tx_wait_more)
758  		kcm_write_msgs(kcm);
759  }
760  
761  static ssize_t kcm_sendpage(struct socket *sock, struct page *page,
762  			    int offset, size_t size, int flags)
763  
764  {
765  	struct sock *sk = sock->sk;
766  	struct kcm_sock *kcm = kcm_sk(sk);
767  	struct sk_buff *skb = NULL, *head = NULL;
768  	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
769  	bool eor;
770  	int err = 0;
771  	int i;
772  
773  	if (flags & MSG_SENDPAGE_NOTLAST)
774  		flags |= MSG_MORE;
775  
776  	/* No MSG_EOR from splice, only look at MSG_MORE */
777  	eor = !(flags & MSG_MORE);
778  
779  	lock_sock(sk);
780  
781  	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
782  
783  	err = -EPIPE;
784  	if (sk->sk_err)
785  		goto out_error;
786  
787  	if (kcm->seq_skb) {
788  		/* Previously opened message */
789  		head = kcm->seq_skb;
790  		skb = kcm_tx_msg(head)->last_skb;
791  		i = skb_shinfo(skb)->nr_frags;
792  
793  		if (skb_can_coalesce(skb, i, page, offset)) {
794  			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
795  			skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;
796  			goto coalesced;
797  		}
798  
799  		if (i >= MAX_SKB_FRAGS) {
800  			struct sk_buff *tskb;
801  
802  			tskb = alloc_skb(0, sk->sk_allocation);
803  			while (!tskb) {
804  				kcm_push(kcm);
805  				err = sk_stream_wait_memory(sk, &timeo);
806  				if (err)
807  					goto out_error;
808  			}
809  
810  			if (head == skb)
811  				skb_shinfo(head)->frag_list = tskb;
812  			else
813  				skb->next = tskb;
814  
815  			skb = tskb;
816  			skb->ip_summed = CHECKSUM_UNNECESSARY;
817  			i = 0;
818  		}
819  	} else {
820  		/* Call the sk_stream functions to manage the sndbuf mem. */
821  		if (!sk_stream_memory_free(sk)) {
822  			kcm_push(kcm);
823  			set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
824  			err = sk_stream_wait_memory(sk, &timeo);
825  			if (err)
826  				goto out_error;
827  		}
828  
829  		head = alloc_skb(0, sk->sk_allocation);
830  		while (!head) {
831  			kcm_push(kcm);
832  			err = sk_stream_wait_memory(sk, &timeo);
833  			if (err)
834  				goto out_error;
835  		}
836  
837  		skb = head;
838  		i = 0;
839  	}
840  
841  	get_page(page);
842  	skb_fill_page_desc_noacc(skb, i, page, offset, size);
843  	skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;
844  
845  coalesced:
846  	skb->len += size;
847  	skb->data_len += size;
848  	skb->truesize += size;
849  	sk->sk_wmem_queued += size;
850  	sk_mem_charge(sk, size);
851  
852  	if (head != skb) {
853  		head->len += size;
854  		head->data_len += size;
855  		head->truesize += size;
856  	}
857  
858  	if (eor) {
859  		bool not_busy = skb_queue_empty(&sk->sk_write_queue);
860  
861  		/* Message complete, queue it on send buffer */
862  		__skb_queue_tail(&sk->sk_write_queue, head);
863  		kcm->seq_skb = NULL;
864  		KCM_STATS_INCR(kcm->stats.tx_msgs);
865  
866  		if (flags & MSG_BATCH) {
867  			kcm->tx_wait_more = true;
868  		} else if (kcm->tx_wait_more || not_busy) {
869  			err = kcm_write_msgs(kcm);
870  			if (err < 0) {
871  				/* We got a hard error in write_msgs but have
872  				 * already queued this message. Report an error
873  				 * in the socket, but don't affect return value
874  				 * from sendmsg
875  				 */
876  				pr_warn("KCM: Hard failure on kcm_write_msgs\n");
877  				report_csk_error(&kcm->sk, -err);
878  			}
879  		}
880  	} else {
881  		/* Message not complete, save state */
882  		kcm->seq_skb = head;
883  		kcm_tx_msg(head)->last_skb = skb;
884  	}
885  
886  	KCM_STATS_ADD(kcm->stats.tx_bytes, size);
887  
888  	release_sock(sk);
889  	return size;
890  
891  out_error:
892  	kcm_push(kcm);
893  
894  	err = sk_stream_error(sk, flags, err);
895  
896  	/* make sure we wake any epoll edge trigger waiter */
897  	if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
898  		sk->sk_write_space(sk);
899  
900  	release_sock(sk);
901  	return err;
902  }
903  
904  static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
905  {
906  	struct sock *sk = sock->sk;
907  	struct kcm_sock *kcm = kcm_sk(sk);
908  	struct sk_buff *skb = NULL, *head = NULL;
909  	size_t copy, copied = 0;
910  	long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
911  	int eor = (sock->type == SOCK_DGRAM) ?
912  		  !(msg->msg_flags & MSG_MORE) : !!(msg->msg_flags & MSG_EOR);
913  	int err = -EPIPE;
914  
915  	lock_sock(sk);
916  
917  	/* Per tcp_sendmsg this should be in poll */
918  	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
919  
920  	if (sk->sk_err)
921  		goto out_error;
922  
923  	if (kcm->seq_skb) {
924  		/* Previously opened message */
925  		head = kcm->seq_skb;
926  		skb = kcm_tx_msg(head)->last_skb;
927  		goto start;
928  	}
929  
930  	/* Call the sk_stream functions to manage the sndbuf mem. */
931  	if (!sk_stream_memory_free(sk)) {
932  		kcm_push(kcm);
933  		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
934  		err = sk_stream_wait_memory(sk, &timeo);
935  		if (err)
936  			goto out_error;
937  	}
938  
939  	if (msg_data_left(msg)) {
940  		/* New message, alloc head skb */
941  		head = alloc_skb(0, sk->sk_allocation);
942  		while (!head) {
943  			kcm_push(kcm);
944  			err = sk_stream_wait_memory(sk, &timeo);
945  			if (err)
946  				goto out_error;
947  
948  			head = alloc_skb(0, sk->sk_allocation);
949  		}
950  
951  		skb = head;
952  
953  		/* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
954  		 * csum_and_copy_from_iter from skb_do_copy_data_nocache.
955  		 */
956  		skb->ip_summed = CHECKSUM_UNNECESSARY;
957  	}
958  
959  start:
960  	while (msg_data_left(msg)) {
961  		bool merge = true;
962  		int i = skb_shinfo(skb)->nr_frags;
963  		struct page_frag *pfrag = sk_page_frag(sk);
964  
965  		if (!sk_page_frag_refill(sk, pfrag))
966  			goto wait_for_memory;
967  
968  		if (!skb_can_coalesce(skb, i, pfrag->page,
969  				      pfrag->offset)) {
970  			if (i == MAX_SKB_FRAGS) {
971  				struct sk_buff *tskb;
972  
973  				tskb = alloc_skb(0, sk->sk_allocation);
974  				if (!tskb)
975  					goto wait_for_memory;
976  
977  				if (head == skb)
978  					skb_shinfo(head)->frag_list = tskb;
979  				else
980  					skb->next = tskb;
981  
982  				skb = tskb;
983  				skb->ip_summed = CHECKSUM_UNNECESSARY;
984  				continue;
985  			}
986  			merge = false;
987  		}
988  
989  		copy = min_t(int, msg_data_left(msg),
990  			     pfrag->size - pfrag->offset);
991  
992  		if (!sk_wmem_schedule(sk, copy))
993  			goto wait_for_memory;
994  
995  		err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
996  					       pfrag->page,
997  					       pfrag->offset,
998  					       copy);
999  		if (err)
1000  			goto out_error;
1001  
1002  		/* Update the skb. */
1003  		if (merge) {
1004  			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1005  		} else {
1006  			skb_fill_page_desc(skb, i, pfrag->page,
1007  					   pfrag->offset, copy);
1008  			get_page(pfrag->page);
1009  		}
1010  
1011  		pfrag->offset += copy;
1012  		copied += copy;
1013  		if (head != skb) {
1014  			head->len += copy;
1015  			head->data_len += copy;
1016  		}
1017  
1018  		continue;
1019  
1020  wait_for_memory:
1021  		kcm_push(kcm);
1022  		err = sk_stream_wait_memory(sk, &timeo);
1023  		if (err)
1024  			goto out_error;
1025  	}
1026  
1027  	if (eor) {
1028  		bool not_busy = skb_queue_empty(&sk->sk_write_queue);
1029  
1030  		if (head) {
1031  			/* Message complete, queue it on send buffer */
1032  			__skb_queue_tail(&sk->sk_write_queue, head);
1033  			kcm->seq_skb = NULL;
1034  			KCM_STATS_INCR(kcm->stats.tx_msgs);
1035  		}
1036  
1037  		if (msg->msg_flags & MSG_BATCH) {
1038  			kcm->tx_wait_more = true;
1039  		} else if (kcm->tx_wait_more || not_busy) {
1040  			err = kcm_write_msgs(kcm);
1041  			if (err < 0) {
1042  				/* We got a hard error in write_msgs but have
1043  				 * already queued this message. Report an error
1044  				 * in the socket, but don't affect return value
1045  				 * from sendmsg
1046  				 */
1047  				pr_warn("KCM: Hard failure on kcm_write_msgs\n");
1048  				report_csk_error(&kcm->sk, -err);
1049  			}
1050  		}
1051  	} else {
1052  		/* Message not complete, save state */
1053  partial_message:
1054  		if (head) {
1055  			kcm->seq_skb = head;
1056  			kcm_tx_msg(head)->last_skb = skb;
1057  		}
1058  	}
1059  
1060  	KCM_STATS_ADD(kcm->stats.tx_bytes, copied);
1061  
1062  	release_sock(sk);
1063  	return copied;
1064  
1065  out_error:
1066  	kcm_push(kcm);
1067  
1068  	if (copied && sock->type == SOCK_SEQPACKET) {
1069  		/* Wrote some bytes before encountering an
1070  		 * error, return partial success.
1071  		 */
1072  		goto partial_message;
1073  	}
1074  
1075  	if (head != kcm->seq_skb)
1076  		kfree_skb(head);
1077  
1078  	err = sk_stream_error(sk, msg->msg_flags, err);
1079  
1080  	/* make sure we wake any epoll edge trigger waiter */
1081  	if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
1082  		sk->sk_write_space(sk);
1083  
1084  	release_sock(sk);
1085  	return err;
1086  }
1087  
1088  static struct sk_buff *kcm_wait_data(struct sock *sk, int flags,
1089  				     long timeo, int *err)
1090  {
1091  	struct sk_buff *skb;
1092  
1093  	while (!(skb = skb_peek(&sk->sk_receive_queue))) {
1094  		if (sk->sk_err) {
1095  			*err = sock_error(sk);
1096  			return NULL;
1097  		}
1098  
1099  		if (sock_flag(sk, SOCK_DONE))
1100  			return NULL;
1101  
1102  		if ((flags & MSG_DONTWAIT) || !timeo) {
1103  			*err = -EAGAIN;
1104  			return NULL;
1105  		}
1106  
1107  		sk_wait_data(sk, &timeo, NULL);
1108  
1109  		/* Handle signals */
1110  		if (signal_pending(current)) {
1111  			*err = sock_intr_errno(timeo);
1112  			return NULL;
1113  		}
1114  	}
1115  
1116  	return skb;
1117  }
1118  
1119  static int kcm_recvmsg(struct socket *sock, struct msghdr *msg,
1120  		       size_t len, int flags)
1121  {
1122  	struct sock *sk = sock->sk;
1123  	struct kcm_sock *kcm = kcm_sk(sk);
1124  	int err = 0;
1125  	long timeo;
1126  	struct strp_msg *stm;
1127  	int copied = 0;
1128  	struct sk_buff *skb;
1129  
1130  	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1131  
1132  	lock_sock(sk);
1133  
1134  	skb = kcm_wait_data(sk, flags, timeo, &err);
1135  	if (!skb)
1136  		goto out;
1137  
1138  	/* Okay, have a message on the receive queue */
1139  
1140  	stm = strp_msg(skb);
1141  
1142  	if (len > stm->full_len)
1143  		len = stm->full_len;
1144  
1145  	err = skb_copy_datagram_msg(skb, stm->offset, msg, len);
1146  	if (err < 0)
1147  		goto out;
1148  
1149  	copied = len;
1150  	if (likely(!(flags & MSG_PEEK))) {
1151  		KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
1152  		if (copied < stm->full_len) {
1153  			if (sock->type == SOCK_DGRAM) {
1154  				/* Truncated message */
1155  				msg->msg_flags |= MSG_TRUNC;
1156  				goto msg_finished;
1157  			}
1158  			stm->offset += copied;
1159  			stm->full_len -= copied;
1160  		} else {
1161  msg_finished:
1162  			/* Finished with message */
1163  			msg->msg_flags |= MSG_EOR;
1164  			KCM_STATS_INCR(kcm->stats.rx_msgs);
1165  			skb_unlink(skb, &sk->sk_receive_queue);
1166  			kfree_skb(skb);
1167  		}
1168  	}
1169  
1170  out:
1171  	release_sock(sk);
1172  
1173  	return copied ? : err;
1174  }
1175  
1176  static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
1177  			       struct pipe_inode_info *pipe, size_t len,
1178  			       unsigned int flags)
1179  {
1180  	struct sock *sk = sock->sk;
1181  	struct kcm_sock *kcm = kcm_sk(sk);
1182  	long timeo;
1183  	struct strp_msg *stm;
1184  	int err = 0;
1185  	ssize_t copied;
1186  	struct sk_buff *skb;
1187  
1188  	/* Only support splice for SOCKSEQPACKET */
1189  
1190  	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1191  
1192  	lock_sock(sk);
1193  
1194  	skb = kcm_wait_data(sk, flags, timeo, &err);
1195  	if (!skb)
1196  		goto err_out;
1197  
1198  	/* Okay, have a message on the receive queue */
1199  
1200  	stm = strp_msg(skb);
1201  
1202  	if (len > stm->full_len)
1203  		len = stm->full_len;
1204  
1205  	copied = skb_splice_bits(skb, sk, stm->offset, pipe, len, flags);
1206  	if (copied < 0) {
1207  		err = copied;
1208  		goto err_out;
1209  	}
1210  
1211  	KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
1212  
1213  	stm->offset += copied;
1214  	stm->full_len -= copied;
1215  
1216  	/* We have no way to return MSG_EOR. If all the bytes have been
1217  	 * read we still leave the message in the receive socket buffer.
1218  	 * A subsequent recvmsg needs to be done to return MSG_EOR and
1219  	 * finish reading the message.
1220  	 */
1221  
1222  	release_sock(sk);
1223  
1224  	return copied;
1225  
1226  err_out:
1227  	release_sock(sk);
1228  
1229  	return err;
1230  }
1231  
1232  /* kcm sock lock held */
1233  static void kcm_recv_disable(struct kcm_sock *kcm)
1234  {
1235  	struct kcm_mux *mux = kcm->mux;
1236  
1237  	if (kcm->rx_disabled)
1238  		return;
1239  
1240  	spin_lock_bh(&mux->rx_lock);
1241  
1242  	kcm->rx_disabled = 1;
1243  
1244  	/* If a psock is reserved we'll do cleanup in unreserve */
1245  	if (!kcm->rx_psock) {
1246  		if (kcm->rx_wait) {
1247  			list_del(&kcm->wait_rx_list);
1248  			/* paired with lockless reads in kcm_rfree() */
1249  			WRITE_ONCE(kcm->rx_wait, false);
1250  		}
1251  
1252  		requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
1253  	}
1254  
1255  	spin_unlock_bh(&mux->rx_lock);
1256  }
1257  
1258  /* kcm sock lock held */
1259  static void kcm_recv_enable(struct kcm_sock *kcm)
1260  {
1261  	struct kcm_mux *mux = kcm->mux;
1262  
1263  	if (!kcm->rx_disabled)
1264  		return;
1265  
1266  	spin_lock_bh(&mux->rx_lock);
1267  
1268  	kcm->rx_disabled = 0;
1269  	kcm_rcv_ready(kcm);
1270  
1271  	spin_unlock_bh(&mux->rx_lock);
1272  }
1273  
1274  static int kcm_setsockopt(struct socket *sock, int level, int optname,
1275  			  sockptr_t optval, unsigned int optlen)
1276  {
1277  	struct kcm_sock *kcm = kcm_sk(sock->sk);
1278  	int val, valbool;
1279  	int err = 0;
1280  
1281  	if (level != SOL_KCM)
1282  		return -ENOPROTOOPT;
1283  
1284  	if (optlen < sizeof(int))
1285  		return -EINVAL;
1286  
1287  	if (copy_from_sockptr(&val, optval, sizeof(int)))
1288  		return -EFAULT;
1289  
1290  	valbool = val ? 1 : 0;
1291  
1292  	switch (optname) {
1293  	case KCM_RECV_DISABLE:
1294  		lock_sock(&kcm->sk);
1295  		if (valbool)
1296  			kcm_recv_disable(kcm);
1297  		else
1298  			kcm_recv_enable(kcm);
1299  		release_sock(&kcm->sk);
1300  		break;
1301  	default:
1302  		err = -ENOPROTOOPT;
1303  	}
1304  
1305  	return err;
1306  }
1307  
1308  static int kcm_getsockopt(struct socket *sock, int level, int optname,
1309  			  char __user *optval, int __user *optlen)
1310  {
1311  	struct kcm_sock *kcm = kcm_sk(sock->sk);
1312  	int val, len;
1313  
1314  	if (level != SOL_KCM)
1315  		return -ENOPROTOOPT;
1316  
1317  	if (get_user(len, optlen))
1318  		return -EFAULT;
1319  
1320  	len = min_t(unsigned int, len, sizeof(int));
1321  	if (len < 0)
1322  		return -EINVAL;
1323  
1324  	switch (optname) {
1325  	case KCM_RECV_DISABLE:
1326  		val = kcm->rx_disabled;
1327  		break;
1328  	default:
1329  		return -ENOPROTOOPT;
1330  	}
1331  
1332  	if (put_user(len, optlen))
1333  		return -EFAULT;
1334  	if (copy_to_user(optval, &val, len))
1335  		return -EFAULT;
1336  	return 0;
1337  }
1338  
1339  static void init_kcm_sock(struct kcm_sock *kcm, struct kcm_mux *mux)
1340  {
1341  	struct kcm_sock *tkcm;
1342  	struct list_head *head;
1343  	int index = 0;
1344  
1345  	/* For SOCK_SEQPACKET sock type, datagram_poll checks the sk_state, so
1346  	 * we set sk_state, otherwise epoll_wait always returns right away with
1347  	 * EPOLLHUP
1348  	 */
1349  	kcm->sk.sk_state = TCP_ESTABLISHED;
1350  
1351  	/* Add to mux's kcm sockets list */
1352  	kcm->mux = mux;
1353  	spin_lock_bh(&mux->lock);
1354  
1355  	head = &mux->kcm_socks;
1356  	list_for_each_entry(tkcm, &mux->kcm_socks, kcm_sock_list) {
1357  		if (tkcm->index != index)
1358  			break;
1359  		head = &tkcm->kcm_sock_list;
1360  		index++;
1361  	}
1362  
1363  	list_add(&kcm->kcm_sock_list, head);
1364  	kcm->index = index;
1365  
1366  	mux->kcm_socks_cnt++;
1367  	spin_unlock_bh(&mux->lock);
1368  
1369  	INIT_WORK(&kcm->tx_work, kcm_tx_work);
1370  
1371  	spin_lock_bh(&mux->rx_lock);
1372  	kcm_rcv_ready(kcm);
1373  	spin_unlock_bh(&mux->rx_lock);
1374  }
1375  
1376  static int kcm_attach(struct socket *sock, struct socket *csock,
1377  		      struct bpf_prog *prog)
1378  {
1379  	struct kcm_sock *kcm = kcm_sk(sock->sk);
1380  	struct kcm_mux *mux = kcm->mux;
1381  	struct sock *csk;
1382  	struct kcm_psock *psock = NULL, *tpsock;
1383  	struct list_head *head;
1384  	int index = 0;
1385  	static const struct strp_callbacks cb = {
1386  		.rcv_msg = kcm_rcv_strparser,
1387  		.parse_msg = kcm_parse_func_strparser,
1388  		.read_sock_done = kcm_read_sock_done,
1389  	};
1390  	int err = 0;
1391  
1392  	csk = csock->sk;
1393  	if (!csk)
1394  		return -EINVAL;
1395  
1396  	lock_sock(csk);
1397  
1398  	/* Only allow TCP sockets to be attached for now */
1399  	if ((csk->sk_family != AF_INET && csk->sk_family != AF_INET6) ||
1400  	    csk->sk_protocol != IPPROTO_TCP) {
1401  		err = -EOPNOTSUPP;
1402  		goto out;
1403  	}
1404  
1405  	/* Don't allow listeners or closed sockets */
1406  	if (csk->sk_state == TCP_LISTEN || csk->sk_state == TCP_CLOSE) {
1407  		err = -EOPNOTSUPP;
1408  		goto out;
1409  	}
1410  
1411  	psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);
1412  	if (!psock) {
1413  		err = -ENOMEM;
1414  		goto out;
1415  	}
1416  
1417  	psock->mux = mux;
1418  	psock->sk = csk;
1419  	psock->bpf_prog = prog;
1420  
1421  	write_lock_bh(&csk->sk_callback_lock);
1422  
1423  	/* Check if sk_user_data is already by KCM or someone else.
1424  	 * Must be done under lock to prevent race conditions.
1425  	 */
1426  	if (csk->sk_user_data) {
1427  		write_unlock_bh(&csk->sk_callback_lock);
1428  		kmem_cache_free(kcm_psockp, psock);
1429  		err = -EALREADY;
1430  		goto out;
1431  	}
1432  
1433  	err = strp_init(&psock->strp, csk, &cb);
1434  	if (err) {
1435  		write_unlock_bh(&csk->sk_callback_lock);
1436  		kmem_cache_free(kcm_psockp, psock);
1437  		goto out;
1438  	}
1439  
1440  	psock->save_data_ready = csk->sk_data_ready;
1441  	psock->save_write_space = csk->sk_write_space;
1442  	psock->save_state_change = csk->sk_state_change;
1443  	csk->sk_user_data = psock;
1444  	csk->sk_data_ready = psock_data_ready;
1445  	csk->sk_write_space = psock_write_space;
1446  	csk->sk_state_change = psock_state_change;
1447  
1448  	write_unlock_bh(&csk->sk_callback_lock);
1449  
1450  	sock_hold(csk);
1451  
1452  	/* Finished initialization, now add the psock to the MUX. */
1453  	spin_lock_bh(&mux->lock);
1454  	head = &mux->psocks;
1455  	list_for_each_entry(tpsock, &mux->psocks, psock_list) {
1456  		if (tpsock->index != index)
1457  			break;
1458  		head = &tpsock->psock_list;
1459  		index++;
1460  	}
1461  
1462  	list_add(&psock->psock_list, head);
1463  	psock->index = index;
1464  
1465  	KCM_STATS_INCR(mux->stats.psock_attach);
1466  	mux->psocks_cnt++;
1467  	psock_now_avail(psock);
1468  	spin_unlock_bh(&mux->lock);
1469  
1470  	/* Schedule RX work in case there are already bytes queued */
1471  	strp_check_rcv(&psock->strp);
1472  
1473  out:
1474  	release_sock(csk);
1475  
1476  	return err;
1477  }
1478  
1479  static int kcm_attach_ioctl(struct socket *sock, struct kcm_attach *info)
1480  {
1481  	struct socket *csock;
1482  	struct bpf_prog *prog;
1483  	int err;
1484  
1485  	csock = sockfd_lookup(info->fd, &err);
1486  	if (!csock)
1487  		return -ENOENT;
1488  
1489  	prog = bpf_prog_get_type(info->bpf_fd, BPF_PROG_TYPE_SOCKET_FILTER);
1490  	if (IS_ERR(prog)) {
1491  		err = PTR_ERR(prog);
1492  		goto out;
1493  	}
1494  
1495  	err = kcm_attach(sock, csock, prog);
1496  	if (err) {
1497  		bpf_prog_put(prog);
1498  		goto out;
1499  	}
1500  
1501  	/* Keep reference on file also */
1502  
1503  	return 0;
1504  out:
1505  	sockfd_put(csock);
1506  	return err;
1507  }
1508  
1509  static void kcm_unattach(struct kcm_psock *psock)
1510  {
1511  	struct sock *csk = psock->sk;
1512  	struct kcm_mux *mux = psock->mux;
1513  
1514  	lock_sock(csk);
1515  
1516  	/* Stop getting callbacks from TCP socket. After this there should
1517  	 * be no way to reserve a kcm for this psock.
1518  	 */
1519  	write_lock_bh(&csk->sk_callback_lock);
1520  	csk->sk_user_data = NULL;
1521  	csk->sk_data_ready = psock->save_data_ready;
1522  	csk->sk_write_space = psock->save_write_space;
1523  	csk->sk_state_change = psock->save_state_change;
1524  	strp_stop(&psock->strp);
1525  
1526  	if (WARN_ON(psock->rx_kcm)) {
1527  		write_unlock_bh(&csk->sk_callback_lock);
1528  		release_sock(csk);
1529  		return;
1530  	}
1531  
1532  	spin_lock_bh(&mux->rx_lock);
1533  
1534  	/* Stop receiver activities. After this point psock should not be
1535  	 * able to get onto ready list either through callbacks or work.
1536  	 */
1537  	if (psock->ready_rx_msg) {
1538  		list_del(&psock->psock_ready_list);
1539  		kfree_skb(psock->ready_rx_msg);
1540  		psock->ready_rx_msg = NULL;
1541  		KCM_STATS_INCR(mux->stats.rx_ready_drops);
1542  	}
1543  
1544  	spin_unlock_bh(&mux->rx_lock);
1545  
1546  	write_unlock_bh(&csk->sk_callback_lock);
1547  
1548  	/* Call strp_done without sock lock */
1549  	release_sock(csk);
1550  	strp_done(&psock->strp);
1551  	lock_sock(csk);
1552  
1553  	bpf_prog_put(psock->bpf_prog);
1554  
1555  	spin_lock_bh(&mux->lock);
1556  
1557  	aggregate_psock_stats(&psock->stats, &mux->aggregate_psock_stats);
1558  	save_strp_stats(&psock->strp, &mux->aggregate_strp_stats);
1559  
1560  	KCM_STATS_INCR(mux->stats.psock_unattach);
1561  
1562  	if (psock->tx_kcm) {
1563  		/* psock was reserved.  Just mark it finished and we will clean
1564  		 * up in the kcm paths, we need kcm lock which can not be
1565  		 * acquired here.
1566  		 */
1567  		KCM_STATS_INCR(mux->stats.psock_unattach_rsvd);
1568  		spin_unlock_bh(&mux->lock);
1569  
1570  		/* We are unattaching a socket that is reserved. Abort the
1571  		 * socket since we may be out of sync in sending on it. We need
1572  		 * to do this without the mux lock.
1573  		 */
1574  		kcm_abort_tx_psock(psock, EPIPE, false);
1575  
1576  		spin_lock_bh(&mux->lock);
1577  		if (!psock->tx_kcm) {
1578  			/* psock now unreserved in window mux was unlocked */
1579  			goto no_reserved;
1580  		}
1581  		psock->done = 1;
1582  
1583  		/* Commit done before queuing work to process it */
1584  		smp_mb();
1585  
1586  		/* Queue tx work to make sure psock->done is handled */
1587  		queue_work(kcm_wq, &psock->tx_kcm->tx_work);
1588  		spin_unlock_bh(&mux->lock);
1589  	} else {
1590  no_reserved:
1591  		if (!psock->tx_stopped)
1592  			list_del(&psock->psock_avail_list);
1593  		list_del(&psock->psock_list);
1594  		mux->psocks_cnt--;
1595  		spin_unlock_bh(&mux->lock);
1596  
1597  		sock_put(csk);
1598  		fput(csk->sk_socket->file);
1599  		kmem_cache_free(kcm_psockp, psock);
1600  	}
1601  
1602  	release_sock(csk);
1603  }
1604  
1605  static int kcm_unattach_ioctl(struct socket *sock, struct kcm_unattach *info)
1606  {
1607  	struct kcm_sock *kcm = kcm_sk(sock->sk);
1608  	struct kcm_mux *mux = kcm->mux;
1609  	struct kcm_psock *psock;
1610  	struct socket *csock;
1611  	struct sock *csk;
1612  	int err;
1613  
1614  	csock = sockfd_lookup(info->fd, &err);
1615  	if (!csock)
1616  		return -ENOENT;
1617  
1618  	csk = csock->sk;
1619  	if (!csk) {
1620  		err = -EINVAL;
1621  		goto out;
1622  	}
1623  
1624  	err = -ENOENT;
1625  
1626  	spin_lock_bh(&mux->lock);
1627  
1628  	list_for_each_entry(psock, &mux->psocks, psock_list) {
1629  		if (psock->sk != csk)
1630  			continue;
1631  
1632  		/* Found the matching psock */
1633  
1634  		if (psock->unattaching || WARN_ON(psock->done)) {
1635  			err = -EALREADY;
1636  			break;
1637  		}
1638  
1639  		psock->unattaching = 1;
1640  
1641  		spin_unlock_bh(&mux->lock);
1642  
1643  		/* Lower socket lock should already be held */
1644  		kcm_unattach(psock);
1645  
1646  		err = 0;
1647  		goto out;
1648  	}
1649  
1650  	spin_unlock_bh(&mux->lock);
1651  
1652  out:
1653  	sockfd_put(csock);
1654  	return err;
1655  }
1656  
1657  static struct proto kcm_proto = {
1658  	.name	= "KCM",
1659  	.owner	= THIS_MODULE,
1660  	.obj_size = sizeof(struct kcm_sock),
1661  };
1662  
1663  /* Clone a kcm socket. */
1664  static struct file *kcm_clone(struct socket *osock)
1665  {
1666  	struct socket *newsock;
1667  	struct sock *newsk;
1668  
1669  	newsock = sock_alloc();
1670  	if (!newsock)
1671  		return ERR_PTR(-ENFILE);
1672  
1673  	newsock->type = osock->type;
1674  	newsock->ops = osock->ops;
1675  
1676  	__module_get(newsock->ops->owner);
1677  
1678  	newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL,
1679  			 &kcm_proto, false);
1680  	if (!newsk) {
1681  		sock_release(newsock);
1682  		return ERR_PTR(-ENOMEM);
1683  	}
1684  	sock_init_data(newsock, newsk);
1685  	init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux);
1686  
1687  	return sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
1688  }
1689  
1690  static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1691  {
1692  	int err;
1693  
1694  	switch (cmd) {
1695  	case SIOCKCMATTACH: {
1696  		struct kcm_attach info;
1697  
1698  		if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
1699  			return -EFAULT;
1700  
1701  		err = kcm_attach_ioctl(sock, &info);
1702  
1703  		break;
1704  	}
1705  	case SIOCKCMUNATTACH: {
1706  		struct kcm_unattach info;
1707  
1708  		if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
1709  			return -EFAULT;
1710  
1711  		err = kcm_unattach_ioctl(sock, &info);
1712  
1713  		break;
1714  	}
1715  	case SIOCKCMCLONE: {
1716  		struct kcm_clone info;
1717  		struct file *file;
1718  
1719  		info.fd = get_unused_fd_flags(0);
1720  		if (unlikely(info.fd < 0))
1721  			return info.fd;
1722  
1723  		file = kcm_clone(sock);
1724  		if (IS_ERR(file)) {
1725  			put_unused_fd(info.fd);
1726  			return PTR_ERR(file);
1727  		}
1728  		if (copy_to_user((void __user *)arg, &info,
1729  				 sizeof(info))) {
1730  			put_unused_fd(info.fd);
1731  			fput(file);
1732  			return -EFAULT;
1733  		}
1734  		fd_install(info.fd, file);
1735  		err = 0;
1736  		break;
1737  	}
1738  	default:
1739  		err = -ENOIOCTLCMD;
1740  		break;
1741  	}
1742  
1743  	return err;
1744  }
1745  
1746  static void free_mux(struct rcu_head *rcu)
1747  {
1748  	struct kcm_mux *mux = container_of(rcu,
1749  	    struct kcm_mux, rcu);
1750  
1751  	kmem_cache_free(kcm_muxp, mux);
1752  }
1753  
1754  static void release_mux(struct kcm_mux *mux)
1755  {
1756  	struct kcm_net *knet = mux->knet;
1757  	struct kcm_psock *psock, *tmp_psock;
1758  
1759  	/* Release psocks */
1760  	list_for_each_entry_safe(psock, tmp_psock,
1761  				 &mux->psocks, psock_list) {
1762  		if (!WARN_ON(psock->unattaching))
1763  			kcm_unattach(psock);
1764  	}
1765  
1766  	if (WARN_ON(mux->psocks_cnt))
1767  		return;
1768  
1769  	__skb_queue_purge(&mux->rx_hold_queue);
1770  
1771  	mutex_lock(&knet->mutex);
1772  	aggregate_mux_stats(&mux->stats, &knet->aggregate_mux_stats);
1773  	aggregate_psock_stats(&mux->aggregate_psock_stats,
1774  			      &knet->aggregate_psock_stats);
1775  	aggregate_strp_stats(&mux->aggregate_strp_stats,
1776  			     &knet->aggregate_strp_stats);
1777  	list_del_rcu(&mux->kcm_mux_list);
1778  	knet->count--;
1779  	mutex_unlock(&knet->mutex);
1780  
1781  	call_rcu(&mux->rcu, free_mux);
1782  }
1783  
1784  static void kcm_done(struct kcm_sock *kcm)
1785  {
1786  	struct kcm_mux *mux = kcm->mux;
1787  	struct sock *sk = &kcm->sk;
1788  	int socks_cnt;
1789  
1790  	spin_lock_bh(&mux->rx_lock);
1791  	if (kcm->rx_psock) {
1792  		/* Cleanup in unreserve_rx_kcm */
1793  		WARN_ON(kcm->done);
1794  		kcm->rx_disabled = 1;
1795  		kcm->done = 1;
1796  		spin_unlock_bh(&mux->rx_lock);
1797  		return;
1798  	}
1799  
1800  	if (kcm->rx_wait) {
1801  		list_del(&kcm->wait_rx_list);
1802  		/* paired with lockless reads in kcm_rfree() */
1803  		WRITE_ONCE(kcm->rx_wait, false);
1804  	}
1805  	/* Move any pending receive messages to other kcm sockets */
1806  	requeue_rx_msgs(mux, &sk->sk_receive_queue);
1807  
1808  	spin_unlock_bh(&mux->rx_lock);
1809  
1810  	if (WARN_ON(sk_rmem_alloc_get(sk)))
1811  		return;
1812  
1813  	/* Detach from MUX */
1814  	spin_lock_bh(&mux->lock);
1815  
1816  	list_del(&kcm->kcm_sock_list);
1817  	mux->kcm_socks_cnt--;
1818  	socks_cnt = mux->kcm_socks_cnt;
1819  
1820  	spin_unlock_bh(&mux->lock);
1821  
1822  	if (!socks_cnt) {
1823  		/* We are done with the mux now. */
1824  		release_mux(mux);
1825  	}
1826  
1827  	WARN_ON(kcm->rx_wait);
1828  
1829  	sock_put(&kcm->sk);
1830  }
1831  
1832  /* Called by kcm_release to close a KCM socket.
1833   * If this is the last KCM socket on the MUX, destroy the MUX.
1834   */
1835  static int kcm_release(struct socket *sock)
1836  {
1837  	struct sock *sk = sock->sk;
1838  	struct kcm_sock *kcm;
1839  	struct kcm_mux *mux;
1840  	struct kcm_psock *psock;
1841  
1842  	if (!sk)
1843  		return 0;
1844  
1845  	kcm = kcm_sk(sk);
1846  	mux = kcm->mux;
1847  
1848  	lock_sock(sk);
1849  	sock_orphan(sk);
1850  	kfree_skb(kcm->seq_skb);
1851  
1852  	/* Purge queue under lock to avoid race condition with tx_work trying
1853  	 * to act when queue is nonempty. If tx_work runs after this point
1854  	 * it will just return.
1855  	 */
1856  	__skb_queue_purge(&sk->sk_write_queue);
1857  
1858  	/* Set tx_stopped. This is checked when psock is bound to a kcm and we
1859  	 * get a writespace callback. This prevents further work being queued
1860  	 * from the callback (unbinding the psock occurs after canceling work.
1861  	 */
1862  	kcm->tx_stopped = 1;
1863  
1864  	release_sock(sk);
1865  
1866  	spin_lock_bh(&mux->lock);
1867  	if (kcm->tx_wait) {
1868  		/* Take of tx_wait list, after this point there should be no way
1869  		 * that a psock will be assigned to this kcm.
1870  		 */
1871  		list_del(&kcm->wait_psock_list);
1872  		kcm->tx_wait = false;
1873  	}
1874  	spin_unlock_bh(&mux->lock);
1875  
1876  	/* Cancel work. After this point there should be no outside references
1877  	 * to the kcm socket.
1878  	 */
1879  	cancel_work_sync(&kcm->tx_work);
1880  
1881  	lock_sock(sk);
1882  	psock = kcm->tx_psock;
1883  	if (psock) {
1884  		/* A psock was reserved, so we need to kill it since it
1885  		 * may already have some bytes queued from a message. We
1886  		 * need to do this after removing kcm from tx_wait list.
1887  		 */
1888  		kcm_abort_tx_psock(psock, EPIPE, false);
1889  		unreserve_psock(kcm);
1890  	}
1891  	release_sock(sk);
1892  
1893  	WARN_ON(kcm->tx_wait);
1894  	WARN_ON(kcm->tx_psock);
1895  
1896  	sock->sk = NULL;
1897  
1898  	kcm_done(kcm);
1899  
1900  	return 0;
1901  }
1902  
1903  static const struct proto_ops kcm_dgram_ops = {
1904  	.family =	PF_KCM,
1905  	.owner =	THIS_MODULE,
1906  	.release =	kcm_release,
1907  	.bind =		sock_no_bind,
1908  	.connect =	sock_no_connect,
1909  	.socketpair =	sock_no_socketpair,
1910  	.accept =	sock_no_accept,
1911  	.getname =	sock_no_getname,
1912  	.poll =		datagram_poll,
1913  	.ioctl =	kcm_ioctl,
1914  	.listen =	sock_no_listen,
1915  	.shutdown =	sock_no_shutdown,
1916  	.setsockopt =	kcm_setsockopt,
1917  	.getsockopt =	kcm_getsockopt,
1918  	.sendmsg =	kcm_sendmsg,
1919  	.recvmsg =	kcm_recvmsg,
1920  	.mmap =		sock_no_mmap,
1921  	.sendpage =	kcm_sendpage,
1922  };
1923  
1924  static const struct proto_ops kcm_seqpacket_ops = {
1925  	.family =	PF_KCM,
1926  	.owner =	THIS_MODULE,
1927  	.release =	kcm_release,
1928  	.bind =		sock_no_bind,
1929  	.connect =	sock_no_connect,
1930  	.socketpair =	sock_no_socketpair,
1931  	.accept =	sock_no_accept,
1932  	.getname =	sock_no_getname,
1933  	.poll =		datagram_poll,
1934  	.ioctl =	kcm_ioctl,
1935  	.listen =	sock_no_listen,
1936  	.shutdown =	sock_no_shutdown,
1937  	.setsockopt =	kcm_setsockopt,
1938  	.getsockopt =	kcm_getsockopt,
1939  	.sendmsg =	kcm_sendmsg,
1940  	.recvmsg =	kcm_recvmsg,
1941  	.mmap =		sock_no_mmap,
1942  	.sendpage =	kcm_sendpage,
1943  	.splice_read =	kcm_splice_read,
1944  };
1945  
1946  /* Create proto operation for kcm sockets */
1947  static int kcm_create(struct net *net, struct socket *sock,
1948  		      int protocol, int kern)
1949  {
1950  	struct kcm_net *knet = net_generic(net, kcm_net_id);
1951  	struct sock *sk;
1952  	struct kcm_mux *mux;
1953  
1954  	switch (sock->type) {
1955  	case SOCK_DGRAM:
1956  		sock->ops = &kcm_dgram_ops;
1957  		break;
1958  	case SOCK_SEQPACKET:
1959  		sock->ops = &kcm_seqpacket_ops;
1960  		break;
1961  	default:
1962  		return -ESOCKTNOSUPPORT;
1963  	}
1964  
1965  	if (protocol != KCMPROTO_CONNECTED)
1966  		return -EPROTONOSUPPORT;
1967  
1968  	sk = sk_alloc(net, PF_KCM, GFP_KERNEL, &kcm_proto, kern);
1969  	if (!sk)
1970  		return -ENOMEM;
1971  
1972  	/* Allocate a kcm mux, shared between KCM sockets */
1973  	mux = kmem_cache_zalloc(kcm_muxp, GFP_KERNEL);
1974  	if (!mux) {
1975  		sk_free(sk);
1976  		return -ENOMEM;
1977  	}
1978  
1979  	spin_lock_init(&mux->lock);
1980  	spin_lock_init(&mux->rx_lock);
1981  	INIT_LIST_HEAD(&mux->kcm_socks);
1982  	INIT_LIST_HEAD(&mux->kcm_rx_waiters);
1983  	INIT_LIST_HEAD(&mux->kcm_tx_waiters);
1984  
1985  	INIT_LIST_HEAD(&mux->psocks);
1986  	INIT_LIST_HEAD(&mux->psocks_ready);
1987  	INIT_LIST_HEAD(&mux->psocks_avail);
1988  
1989  	mux->knet = knet;
1990  
1991  	/* Add new MUX to list */
1992  	mutex_lock(&knet->mutex);
1993  	list_add_rcu(&mux->kcm_mux_list, &knet->mux_list);
1994  	knet->count++;
1995  	mutex_unlock(&knet->mutex);
1996  
1997  	skb_queue_head_init(&mux->rx_hold_queue);
1998  
1999  	/* Init KCM socket */
2000  	sock_init_data(sock, sk);
2001  	init_kcm_sock(kcm_sk(sk), mux);
2002  
2003  	return 0;
2004  }
2005  
2006  static const struct net_proto_family kcm_family_ops = {
2007  	.family = PF_KCM,
2008  	.create = kcm_create,
2009  	.owner  = THIS_MODULE,
2010  };
2011  
2012  static __net_init int kcm_init_net(struct net *net)
2013  {
2014  	struct kcm_net *knet = net_generic(net, kcm_net_id);
2015  
2016  	INIT_LIST_HEAD_RCU(&knet->mux_list);
2017  	mutex_init(&knet->mutex);
2018  
2019  	return 0;
2020  }
2021  
2022  static __net_exit void kcm_exit_net(struct net *net)
2023  {
2024  	struct kcm_net *knet = net_generic(net, kcm_net_id);
2025  
2026  	/* All KCM sockets should be closed at this point, which should mean
2027  	 * that all multiplexors and psocks have been destroyed.
2028  	 */
2029  	WARN_ON(!list_empty(&knet->mux_list));
2030  }
2031  
2032  static struct pernet_operations kcm_net_ops = {
2033  	.init = kcm_init_net,
2034  	.exit = kcm_exit_net,
2035  	.id   = &kcm_net_id,
2036  	.size = sizeof(struct kcm_net),
2037  };
2038  
2039  static int __init kcm_init(void)
2040  {
2041  	int err = -ENOMEM;
2042  
2043  	kcm_muxp = kmem_cache_create("kcm_mux_cache",
2044  				     sizeof(struct kcm_mux), 0,
2045  				     SLAB_HWCACHE_ALIGN, NULL);
2046  	if (!kcm_muxp)
2047  		goto fail;
2048  
2049  	kcm_psockp = kmem_cache_create("kcm_psock_cache",
2050  				       sizeof(struct kcm_psock), 0,
2051  					SLAB_HWCACHE_ALIGN, NULL);
2052  	if (!kcm_psockp)
2053  		goto fail;
2054  
2055  	kcm_wq = create_singlethread_workqueue("kkcmd");
2056  	if (!kcm_wq)
2057  		goto fail;
2058  
2059  	err = proto_register(&kcm_proto, 1);
2060  	if (err)
2061  		goto fail;
2062  
2063  	err = register_pernet_device(&kcm_net_ops);
2064  	if (err)
2065  		goto net_ops_fail;
2066  
2067  	err = sock_register(&kcm_family_ops);
2068  	if (err)
2069  		goto sock_register_fail;
2070  
2071  	err = kcm_proc_init();
2072  	if (err)
2073  		goto proc_init_fail;
2074  
2075  	return 0;
2076  
2077  proc_init_fail:
2078  	sock_unregister(PF_KCM);
2079  
2080  sock_register_fail:
2081  	unregister_pernet_device(&kcm_net_ops);
2082  
2083  net_ops_fail:
2084  	proto_unregister(&kcm_proto);
2085  
2086  fail:
2087  	kmem_cache_destroy(kcm_muxp);
2088  	kmem_cache_destroy(kcm_psockp);
2089  
2090  	if (kcm_wq)
2091  		destroy_workqueue(kcm_wq);
2092  
2093  	return err;
2094  }
2095  
2096  static void __exit kcm_exit(void)
2097  {
2098  	kcm_proc_exit();
2099  	sock_unregister(PF_KCM);
2100  	unregister_pernet_device(&kcm_net_ops);
2101  	proto_unregister(&kcm_proto);
2102  	destroy_workqueue(kcm_wq);
2103  
2104  	kmem_cache_destroy(kcm_muxp);
2105  	kmem_cache_destroy(kcm_psockp);
2106  }
2107  
2108  module_init(kcm_init);
2109  module_exit(kcm_exit);
2110  
2111  MODULE_LICENSE("GPL");
2112  MODULE_ALIAS_NETPROTO(PF_KCM);
2113