1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2016-2018 Netflix, Inc.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/param.h>
33#include <sys/kernel.h>
34#include <sys/lock.h>
35#include <sys/malloc.h>
36#include <sys/mutex.h>
37#include <sys/queue.h>
38#include <sys/refcount.h>
39#include <sys/rwlock.h>
40#include <sys/socket.h>
41#include <sys/socketvar.h>
42#include <sys/sysctl.h>
43#include <sys/tree.h>
44#include <sys/counter.h>
45
46#include <dev/tcp_log/tcp_log_dev.h>
47
48#include <net/if.h>
49#include <net/if_var.h>
50#include <net/vnet.h>
51
52#include <netinet/in.h>
53#include <netinet/in_pcb.h>
54#include <netinet/in_var.h>
55#include <netinet/tcp_var.h>
56#include <netinet/tcp_log_buf.h>
57
58/* Default expiry time */
59#define	TCP_LOG_EXPIRE_TIME	((sbintime_t)60 * SBT_1S)
60
61/* Max interval at which to run the expiry timer */
62#define	TCP_LOG_EXPIRE_INTVL	((sbintime_t)5 * SBT_1S)
63
64bool	tcp_log_verbose;
65static uma_zone_t tcp_log_bucket_zone, tcp_log_node_zone, tcp_log_zone;
66static int	tcp_log_session_limit = TCP_LOG_BUF_DEFAULT_SESSION_LIMIT;
67static uint32_t	tcp_log_version = TCP_LOG_BUF_VER;
68RB_HEAD(tcp_log_id_tree, tcp_log_id_bucket);
69static struct tcp_log_id_tree tcp_log_id_head;
70static STAILQ_HEAD(, tcp_log_id_node) tcp_log_expireq_head =
71    STAILQ_HEAD_INITIALIZER(tcp_log_expireq_head);
72static struct mtx tcp_log_expireq_mtx;
73static struct callout tcp_log_expireq_callout;
74static u_long tcp_log_auto_ratio = 0;
75static volatile u_long tcp_log_auto_ratio_cur = 0;
76static uint32_t tcp_log_auto_mode = TCP_LOG_STATE_TAIL;
77static bool tcp_log_auto_all = false;
78
79RB_PROTOTYPE_STATIC(tcp_log_id_tree, tcp_log_id_bucket, tlb_rb, tcp_log_id_cmp)
80
81SYSCTL_NODE(_net_inet_tcp, OID_AUTO, bb, CTLFLAG_RW, 0, "TCP Black Box controls");
82
83SYSCTL_BOOL(_net_inet_tcp_bb, OID_AUTO, log_verbose, CTLFLAG_RW, &tcp_log_verbose,
84    0, "Force verbose logging for TCP traces");
85
86SYSCTL_INT(_net_inet_tcp_bb, OID_AUTO, log_session_limit,
87    CTLFLAG_RW, &tcp_log_session_limit, 0,
88    "Maximum number of events maintained for each TCP session");
89
90SYSCTL_UMA_MAX(_net_inet_tcp_bb, OID_AUTO, log_global_limit, CTLFLAG_RW,
91    &tcp_log_zone, "Maximum number of events maintained for all TCP sessions");
92
93SYSCTL_UMA_CUR(_net_inet_tcp_bb, OID_AUTO, log_global_entries, CTLFLAG_RD,
94    &tcp_log_zone, "Current number of events maintained for all TCP sessions");
95
96SYSCTL_UMA_MAX(_net_inet_tcp_bb, OID_AUTO, log_id_limit, CTLFLAG_RW,
97    &tcp_log_bucket_zone, "Maximum number of log IDs");
98
99SYSCTL_UMA_CUR(_net_inet_tcp_bb, OID_AUTO, log_id_entries, CTLFLAG_RD,
100    &tcp_log_bucket_zone, "Current number of log IDs");
101
102SYSCTL_UMA_MAX(_net_inet_tcp_bb, OID_AUTO, log_id_tcpcb_limit, CTLFLAG_RW,
103    &tcp_log_node_zone, "Maximum number of tcpcbs with log IDs");
104
105SYSCTL_UMA_CUR(_net_inet_tcp_bb, OID_AUTO, log_id_tcpcb_entries, CTLFLAG_RD,
106    &tcp_log_node_zone, "Current number of tcpcbs with log IDs");
107
108SYSCTL_U32(_net_inet_tcp_bb, OID_AUTO, log_version, CTLFLAG_RD, &tcp_log_version,
109    0, "Version of log formats exported");
110
111SYSCTL_ULONG(_net_inet_tcp_bb, OID_AUTO, log_auto_ratio, CTLFLAG_RW,
112    &tcp_log_auto_ratio, 0, "Do auto capturing for 1 out of N sessions");
113
114SYSCTL_U32(_net_inet_tcp_bb, OID_AUTO, log_auto_mode, CTLFLAG_RW,
115    &tcp_log_auto_mode, TCP_LOG_STATE_HEAD_AUTO,
116    "Logging mode for auto-selected sessions (default is TCP_LOG_STATE_HEAD_AUTO)");
117
118SYSCTL_BOOL(_net_inet_tcp_bb, OID_AUTO, log_auto_all, CTLFLAG_RW,
119    &tcp_log_auto_all, false,
120    "Auto-select from all sessions (rather than just those with IDs)");
121
122#ifdef TCPLOG_DEBUG_COUNTERS
123counter_u64_t tcp_log_queued;
124counter_u64_t tcp_log_que_fail1;
125counter_u64_t tcp_log_que_fail2;
126counter_u64_t tcp_log_que_fail3;
127counter_u64_t tcp_log_que_fail4;
128counter_u64_t tcp_log_que_fail5;
129counter_u64_t tcp_log_que_copyout;
130counter_u64_t tcp_log_que_read;
131counter_u64_t tcp_log_que_freed;
132
133SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, queued, CTLFLAG_RD,
134    &tcp_log_queued, "Number of entries queued");
135SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, fail1, CTLFLAG_RD,
136    &tcp_log_que_fail1, "Number of entries queued but fail 1");
137SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, fail2, CTLFLAG_RD,
138    &tcp_log_que_fail2, "Number of entries queued but fail 2");
139SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, fail3, CTLFLAG_RD,
140    &tcp_log_que_fail3, "Number of entries queued but fail 3");
141SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, fail4, CTLFLAG_RD,
142    &tcp_log_que_fail4, "Number of entries queued but fail 4");
143SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, fail5, CTLFLAG_RD,
144    &tcp_log_que_fail5, "Number of entries queued but fail 4");
145SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, copyout, CTLFLAG_RD,
146    &tcp_log_que_copyout, "Number of entries copied out");
147SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, read, CTLFLAG_RD,
148    &tcp_log_que_read, "Number of entries read from the queue");
149SYSCTL_COUNTER_U64(_net_inet_tcp_bb, OID_AUTO, freed, CTLFLAG_RD,
150    &tcp_log_que_freed, "Number of entries freed after reading");
151#endif
152
153#ifdef INVARIANTS
154#define	TCPLOG_DEBUG_RINGBUF
155#endif
156
157struct tcp_log_mem
158{
159	STAILQ_ENTRY(tcp_log_mem) tlm_queue;
160	struct tcp_log_buffer	tlm_buf;
161	struct tcp_log_verbose	tlm_v;
162#ifdef TCPLOG_DEBUG_RINGBUF
163	volatile int		tlm_refcnt;
164#endif
165};
166
167/* 60 bytes for the header, + 16 bytes for padding */
168static uint8_t	zerobuf[76];
169
170/*
171 * Lock order:
172 * 1. TCPID_TREE
173 * 2. TCPID_BUCKET
174 * 3. INP
175 *
176 * Rules:
177 * A. You need a lock on the Tree to add/remove buckets.
178 * B. You need a lock on the bucket to add/remove nodes from the bucket.
179 * C. To change information in a node, you need the INP lock if the tln_closed
180 *    field is false. Otherwise, you need the bucket lock. (Note that the
181 *    tln_closed field can change at any point, so you need to recheck the
182 *    entry after acquiring the INP lock.)
183 * D. To remove a node from the bucket, you must have that entry locked,
184 *    according to the criteria of Rule C. Also, the node must not be on
185 *    the expiry queue.
186 * E. The exception to C is the expiry queue fields, which are locked by
187 *    the TCPLOG_EXPIREQ lock.
188 *
189 * Buckets have a reference count. Each node is a reference. Further,
190 * other callers may add reference counts to keep a bucket from disappearing.
191 * You can add a reference as long as you own a lock sufficient to keep the
192 * bucket from disappearing. For example, a common use is:
193 *   a. Have a locked INP, but need to lock the TCPID_BUCKET.
194 *   b. Add a refcount on the bucket. (Safe because the INP lock prevents
195 *      the TCPID_BUCKET from going away.)
196 *   c. Drop the INP lock.
197 *   d. Acquire a lock on the TCPID_BUCKET.
198 *   e. Acquire a lock on the INP.
199 *   f. Drop the refcount on the bucket.
200 *      (At this point, the bucket may disappear.)
201 *
202 * Expire queue lock:
203 * You can acquire this with either the bucket or INP lock. Don't reverse it.
204 * When the expire code has committed to freeing a node, it resets the expiry
205 * time to SBT_MAX. That is the signal to everyone else that they should
206 * leave that node alone.
207 */
208static struct rwlock tcp_id_tree_lock;
209#define	TCPID_TREE_WLOCK()		rw_wlock(&tcp_id_tree_lock)
210#define	TCPID_TREE_RLOCK()		rw_rlock(&tcp_id_tree_lock)
211#define	TCPID_TREE_UPGRADE()		rw_try_upgrade(&tcp_id_tree_lock)
212#define	TCPID_TREE_WUNLOCK()		rw_wunlock(&tcp_id_tree_lock)
213#define	TCPID_TREE_RUNLOCK()		rw_runlock(&tcp_id_tree_lock)
214#define	TCPID_TREE_WLOCK_ASSERT()	rw_assert(&tcp_id_tree_lock, RA_WLOCKED)
215#define	TCPID_TREE_RLOCK_ASSERT()	rw_assert(&tcp_id_tree_lock, RA_RLOCKED)
216#define	TCPID_TREE_UNLOCK_ASSERT()	rw_assert(&tcp_id_tree_lock, RA_UNLOCKED)
217
218#define	TCPID_BUCKET_LOCK_INIT(tlb)	mtx_init(&((tlb)->tlb_mtx), "tcp log id bucket", NULL, MTX_DEF)
219#define	TCPID_BUCKET_LOCK_DESTROY(tlb)	mtx_destroy(&((tlb)->tlb_mtx))
220#define	TCPID_BUCKET_LOCK(tlb)		mtx_lock(&((tlb)->tlb_mtx))
221#define	TCPID_BUCKET_UNLOCK(tlb)	mtx_unlock(&((tlb)->tlb_mtx))
222#define	TCPID_BUCKET_LOCK_ASSERT(tlb)	mtx_assert(&((tlb)->tlb_mtx), MA_OWNED)
223#define	TCPID_BUCKET_UNLOCK_ASSERT(tlb) mtx_assert(&((tlb)->tlb_mtx), MA_NOTOWNED)
224
225#define	TCPID_BUCKET_REF(tlb)		refcount_acquire(&((tlb)->tlb_refcnt))
226#define	TCPID_BUCKET_UNREF(tlb)		refcount_release(&((tlb)->tlb_refcnt))
227
228#define	TCPLOG_EXPIREQ_LOCK()		mtx_lock(&tcp_log_expireq_mtx)
229#define	TCPLOG_EXPIREQ_UNLOCK()		mtx_unlock(&tcp_log_expireq_mtx)
230
231SLIST_HEAD(tcp_log_id_head, tcp_log_id_node);
232
233struct tcp_log_id_bucket
234{
235	/*
236	 * tlb_id must be first. This lets us use strcmp on
237	 * (struct tcp_log_id_bucket *) and (char *) interchangeably.
238	 */
239	char				tlb_id[TCP_LOG_ID_LEN];
240	RB_ENTRY(tcp_log_id_bucket)	tlb_rb;
241	struct tcp_log_id_head		tlb_head;
242	struct mtx			tlb_mtx;
243	volatile u_int			tlb_refcnt;
244};
245
246struct tcp_log_id_node
247{
248	SLIST_ENTRY(tcp_log_id_node) tln_list;
249	STAILQ_ENTRY(tcp_log_id_node) tln_expireq; /* Locked by the expireq lock */
250	sbintime_t		tln_expiretime;	/* Locked by the expireq lock */
251
252	/*
253	 * If INP is NULL, that means the connection has closed. We've
254	 * saved the connection endpoint information and the log entries
255	 * in the tln_ie and tln_entries members. We've also saved a pointer
256	 * to the enclosing bucket here. If INP is not NULL, the information is
257	 * in the PCB and not here.
258	 */
259	struct inpcb		*tln_inp;
260	struct tcpcb		*tln_tp;
261	struct tcp_log_id_bucket *tln_bucket;
262	struct in_endpoints	tln_ie;
263	struct tcp_log_stailq	tln_entries;
264	int			tln_count;
265	volatile int		tln_closed;
266	uint8_t			tln_af;
267};
268
269enum tree_lock_state {
270	TREE_UNLOCKED = 0,
271	TREE_RLOCKED,
272	TREE_WLOCKED,
273};
274
275/* Do we want to select this session for auto-logging? */
276static __inline bool
277tcp_log_selectauto(void)
278{
279
280	/*
281	 * If we are doing auto-capturing, figure out whether we will capture
282	 * this session.
283	 */
284	if (tcp_log_auto_ratio &&
285	    (atomic_fetchadd_long(&tcp_log_auto_ratio_cur, 1) %
286	    tcp_log_auto_ratio) == 0)
287		return (true);
288	return (false);
289}
290
291static __inline int
292tcp_log_id_cmp(struct tcp_log_id_bucket *a, struct tcp_log_id_bucket *b)
293{
294	KASSERT(a != NULL, ("tcp_log_id_cmp: argument a is unexpectedly NULL"));
295	KASSERT(b != NULL, ("tcp_log_id_cmp: argument b is unexpectedly NULL"));
296	return strncmp(a->tlb_id, b->tlb_id, TCP_LOG_ID_LEN);
297}
298
299RB_GENERATE_STATIC(tcp_log_id_tree, tcp_log_id_bucket, tlb_rb, tcp_log_id_cmp)
300
301static __inline void
302tcp_log_id_validate_tree_lock(int tree_locked)
303{
304
305#ifdef INVARIANTS
306	switch (tree_locked) {
307	case TREE_WLOCKED:
308		TCPID_TREE_WLOCK_ASSERT();
309		break;
310	case TREE_RLOCKED:
311		TCPID_TREE_RLOCK_ASSERT();
312		break;
313	case TREE_UNLOCKED:
314		TCPID_TREE_UNLOCK_ASSERT();
315		break;
316	default:
317		kassert_panic("%s:%d: unknown tree lock state", __func__,
318		    __LINE__);
319	}
320#endif
321}
322
323static __inline void
324tcp_log_remove_bucket(struct tcp_log_id_bucket *tlb)
325{
326
327	TCPID_TREE_WLOCK_ASSERT();
328	KASSERT(SLIST_EMPTY(&tlb->tlb_head),
329	    ("%s: Attempt to remove non-empty bucket", __func__));
330	if (RB_REMOVE(tcp_log_id_tree, &tcp_log_id_head, tlb) == NULL) {
331#ifdef INVARIANTS
332		kassert_panic("%s:%d: error removing element from tree",
333			    __func__, __LINE__);
334#endif
335	}
336	TCPID_BUCKET_LOCK_DESTROY(tlb);
337	uma_zfree(tcp_log_bucket_zone, tlb);
338}
339
340/*
341 * Call with a referenced and locked bucket.
342 * Will return true if the bucket was freed; otherwise, false.
343 * tlb: The bucket to unreference.
344 * tree_locked: A pointer to the state of the tree lock. If the tree lock
345 *    state changes, the function will update it.
346 * inp: If not NULL and the function needs to drop the inp lock to relock the
347 *    tree, it will do so. (The caller must ensure inp will not become invalid,
348 *    probably by holding a reference to it.)
349 */
350static bool
351tcp_log_unref_bucket(struct tcp_log_id_bucket *tlb, int *tree_locked,
352    struct inpcb *inp)
353{
354
355	KASSERT(tlb != NULL, ("%s: called with NULL tlb", __func__));
356	KASSERT(tree_locked != NULL, ("%s: called with NULL tree_locked",
357	    __func__));
358
359	tcp_log_id_validate_tree_lock(*tree_locked);
360
361	/*
362	 * Did we hold the last reference on the tlb? If so, we may need
363	 * to free it. (Note that we can realistically only execute the
364	 * loop twice: once without a write lock and once with a write
365	 * lock.)
366	 */
367	while (TCPID_BUCKET_UNREF(tlb)) {
368		/*
369		 * We need a write lock on the tree to free this.
370		 * If we can upgrade the tree lock, this is "easy". If we
371		 * can't upgrade the tree lock, we need to do this the
372		 * "hard" way: unwind all our locks and relock everything.
373		 * In the meantime, anything could have changed. We even
374		 * need to validate that we still need to free the bucket.
375		 */
376		if (*tree_locked == TREE_RLOCKED && TCPID_TREE_UPGRADE())
377			*tree_locked = TREE_WLOCKED;
378		else if (*tree_locked != TREE_WLOCKED) {
379			TCPID_BUCKET_REF(tlb);
380			if (inp != NULL)
381				INP_WUNLOCK(inp);
382			TCPID_BUCKET_UNLOCK(tlb);
383			if (*tree_locked == TREE_RLOCKED)
384				TCPID_TREE_RUNLOCK();
385			TCPID_TREE_WLOCK();
386			*tree_locked = TREE_WLOCKED;
387			TCPID_BUCKET_LOCK(tlb);
388			if (inp != NULL)
389				INP_WLOCK(inp);
390			continue;
391		}
392
393		/*
394		 * We have an empty bucket and a write lock on the tree.
395		 * Remove the empty bucket.
396		 */
397		tcp_log_remove_bucket(tlb);
398		return (true);
399	}
400	return (false);
401}
402
403/*
404 * Call with a locked bucket. This function will release the lock on the
405 * bucket before returning.
406 *
407 * The caller is responsible for freeing the tp->t_lin/tln node!
408 *
409 * Note: one of tp or both tlb and tln must be supplied.
410 *
411 * inp: A pointer to the inp. If the function needs to drop the inp lock to
412 *    acquire the tree write lock, it will do so. (The caller must ensure inp
413 *    will not become invalid, probably by holding a reference to it.)
414 * tp: A pointer to the tcpcb. (optional; if specified, tlb and tln are ignored)
415 * tlb: A pointer to the bucket. (optional; ignored if tp is specified)
416 * tln: A pointer to the node. (optional; ignored if tp is specified)
417 * tree_locked: A pointer to the state of the tree lock. If the tree lock
418 *    state changes, the function will update it.
419 *
420 * Will return true if the INP lock was reacquired; otherwise, false.
421 */
422static bool
423tcp_log_remove_id_node(struct inpcb *inp, struct tcpcb *tp,
424    struct tcp_log_id_bucket *tlb, struct tcp_log_id_node *tln,
425    int *tree_locked)
426{
427	int orig_tree_locked;
428
429	KASSERT(tp != NULL || (tlb != NULL && tln != NULL),
430	    ("%s: called with tp=%p, tlb=%p, tln=%p", __func__,
431	    tp, tlb, tln));
432	KASSERT(tree_locked != NULL, ("%s: called with NULL tree_locked",
433	    __func__));
434
435	if (tp != NULL) {
436		tlb = tp->t_lib;
437		tln = tp->t_lin;
438		KASSERT(tlb != NULL, ("%s: unexpectedly NULL tlb", __func__));
439		KASSERT(tln != NULL, ("%s: unexpectedly NULL tln", __func__));
440	}
441
442	tcp_log_id_validate_tree_lock(*tree_locked);
443	TCPID_BUCKET_LOCK_ASSERT(tlb);
444
445	/*
446	 * Remove the node, clear the log bucket and node from the TCPCB, and
447	 * decrement the bucket refcount. In the process, if this is the
448	 * last reference, the bucket will be freed.
449	 */
450	SLIST_REMOVE(&tlb->tlb_head, tln, tcp_log_id_node, tln_list);
451	if (tp != NULL) {
452		tp->t_lib = NULL;
453		tp->t_lin = NULL;
454	}
455	orig_tree_locked = *tree_locked;
456	if (!tcp_log_unref_bucket(tlb, tree_locked, inp))
457		TCPID_BUCKET_UNLOCK(tlb);
458	return (*tree_locked != orig_tree_locked);
459}
460
461#define	RECHECK_INP_CLEAN(cleanup)	do {			\
462	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {	\
463		rv = ECONNRESET;				\
464		cleanup;					\
465		goto done;					\
466	}							\
467	tp = intotcpcb(inp);					\
468} while (0)
469
470#define	RECHECK_INP()	RECHECK_INP_CLEAN(/* noop */)
471
472static void
473tcp_log_grow_tlb(char *tlb_id, struct tcpcb *tp)
474{
475
476	INP_WLOCK_ASSERT(tp->t_inpcb);
477
478#ifdef NETFLIX
479	if (V_tcp_perconn_stats_enable == 2 && tp->t_stats == NULL)
480		(void)tcp_stats_sample_rollthedice(tp, tlb_id, strlen(tlb_id));
481#endif
482}
483
484/*
485 * Set the TCP log ID for a TCPCB.
486 * Called with INPCB locked. Returns with it unlocked.
487 */
488int
489tcp_log_set_id(struct tcpcb *tp, char *id)
490{
491	struct tcp_log_id_bucket *tlb, *tmp_tlb;
492	struct tcp_log_id_node *tln;
493	struct inpcb *inp;
494	int tree_locked, rv;
495	bool bucket_locked;
496
497	tlb = NULL;
498	tln = NULL;
499	inp = tp->t_inpcb;
500	tree_locked = TREE_UNLOCKED;
501	bucket_locked = false;
502
503restart:
504	INP_WLOCK_ASSERT(inp);
505
506	/* See if the ID is unchanged. */
507	if ((tp->t_lib != NULL && !strcmp(tp->t_lib->tlb_id, id)) ||
508	    (tp->t_lib == NULL && *id == 0)) {
509		rv = 0;
510		goto done;
511	}
512
513	/*
514	 * If the TCPCB had a previous ID, we need to extricate it from
515	 * the previous list.
516	 *
517	 * Drop the TCPCB lock and lock the tree and the bucket.
518	 * Because this is called in the socket context, we (theoretically)
519	 * don't need to worry about the INPCB completely going away
520	 * while we are gone.
521	 */
522	if (tp->t_lib != NULL) {
523		tlb = tp->t_lib;
524		TCPID_BUCKET_REF(tlb);
525		INP_WUNLOCK(inp);
526
527		if (tree_locked == TREE_UNLOCKED) {
528			TCPID_TREE_RLOCK();
529			tree_locked = TREE_RLOCKED;
530		}
531		TCPID_BUCKET_LOCK(tlb);
532		bucket_locked = true;
533		INP_WLOCK(inp);
534
535		/*
536		 * Unreference the bucket. If our bucket went away, it is no
537		 * longer locked or valid.
538		 */
539		if (tcp_log_unref_bucket(tlb, &tree_locked, inp)) {
540			bucket_locked = false;
541			tlb = NULL;
542		}
543
544		/* Validate the INP. */
545		RECHECK_INP();
546
547		/*
548		 * Evaluate whether the bucket changed while we were unlocked.
549		 *
550		 * Possible scenarios here:
551		 * 1. Bucket is unchanged and the same one we started with.
552		 * 2. The TCPCB no longer has a bucket and our bucket was
553		 *    freed.
554		 * 3. The TCPCB has a new bucket, whether ours was freed.
555		 * 4. The TCPCB no longer has a bucket and our bucket was
556		 *    not freed.
557		 *
558		 * In cases 2-4, we will start over. In case 1, we will
559		 * proceed here to remove the bucket.
560		 */
561		if (tlb == NULL || tp->t_lib != tlb) {
562			KASSERT(bucket_locked || tlb == NULL,
563			    ("%s: bucket_locked (%d) and tlb (%p) are "
564			    "inconsistent", __func__, bucket_locked, tlb));
565
566			if (bucket_locked) {
567				TCPID_BUCKET_UNLOCK(tlb);
568				bucket_locked = false;
569				tlb = NULL;
570			}
571			goto restart;
572		}
573
574		/*
575		 * Store the (struct tcp_log_id_node) for reuse. Then, remove
576		 * it from the bucket. In the process, we may end up relocking.
577		 * If so, we need to validate that the INP is still valid, and
578		 * the TCPCB entries match we expect.
579		 *
580		 * We will clear tlb and change the bucket_locked state just
581		 * before calling tcp_log_remove_id_node(), since that function
582		 * will unlock the bucket.
583		 */
584		if (tln != NULL)
585			uma_zfree(tcp_log_node_zone, tln);
586		tln = tp->t_lin;
587		tlb = NULL;
588		bucket_locked = false;
589		if (tcp_log_remove_id_node(inp, tp, NULL, NULL, &tree_locked)) {
590			RECHECK_INP();
591
592			/*
593			 * If the TCPCB moved to a new bucket while we had
594			 * dropped the lock, restart.
595			 */
596			if (tp->t_lib != NULL || tp->t_lin != NULL)
597				goto restart;
598		}
599
600		/*
601		 * Yay! We successfully removed the TCPCB from its old
602		 * bucket. Phew!
603		 *
604		 * On to bigger and better things...
605		 */
606	}
607
608	/* At this point, the TCPCB should not be in any bucket. */
609	KASSERT(tp->t_lib == NULL, ("%s: tp->t_lib is not NULL", __func__));
610
611	/*
612	 * If the new ID is not empty, we need to now assign this TCPCB to a
613	 * new bucket.
614	 */
615	if (*id) {
616		/* Get a new tln, if we don't already have one to reuse. */
617		if (tln == NULL) {
618			tln = uma_zalloc(tcp_log_node_zone, M_NOWAIT | M_ZERO);
619			if (tln == NULL) {
620				rv = ENOBUFS;
621				goto done;
622			}
623			tln->tln_inp = inp;
624			tln->tln_tp = tp;
625		}
626
627		/*
628		 * Drop the INP lock for a bit. We don't need it, and dropping
629		 * it prevents lock order reversals.
630		 */
631		INP_WUNLOCK(inp);
632
633		/* Make sure we have at least a read lock on the tree. */
634		tcp_log_id_validate_tree_lock(tree_locked);
635		if (tree_locked == TREE_UNLOCKED) {
636			TCPID_TREE_RLOCK();
637			tree_locked = TREE_RLOCKED;
638		}
639
640refind:
641		/*
642		 * Remember that we constructed (struct tcp_log_id_node) so
643		 * we can safely cast the id to it for the purposes of finding.
644		 */
645		KASSERT(tlb == NULL, ("%s:%d tlb unexpectedly non-NULL",
646		    __func__, __LINE__));
647		tmp_tlb = RB_FIND(tcp_log_id_tree, &tcp_log_id_head,
648		    (struct tcp_log_id_bucket *) id);
649
650		/*
651		 * If we didn't find a matching bucket, we need to add a new
652		 * one. This requires a write lock. But, of course, we will
653		 * need to recheck some things when we re-acquire the lock.
654		 */
655		if (tmp_tlb == NULL && tree_locked != TREE_WLOCKED) {
656			tree_locked = TREE_WLOCKED;
657			if (!TCPID_TREE_UPGRADE()) {
658				TCPID_TREE_RUNLOCK();
659				TCPID_TREE_WLOCK();
660
661				/*
662				 * The tree may have changed while we were
663				 * unlocked.
664				 */
665				goto refind;
666			}
667		}
668
669		/* If we need to add a new bucket, do it now. */
670		if (tmp_tlb == NULL) {
671			/* Allocate new bucket. */
672			tlb = uma_zalloc(tcp_log_bucket_zone, M_NOWAIT);
673			if (tlb == NULL) {
674				rv = ENOBUFS;
675				goto done_noinp;
676			}
677
678			/*
679			 * Copy the ID to the bucket.
680			 * NB: Don't use strlcpy() unless you are sure
681			 * we've always validated NULL termination.
682			 *
683			 * TODO: When I'm done writing this, see if we
684			 * we have correctly validated NULL termination and
685			 * can use strlcpy(). :-)
686			 */
687			strncpy(tlb->tlb_id, id, TCP_LOG_ID_LEN - 1);
688			tlb->tlb_id[TCP_LOG_ID_LEN - 1] = '\0';
689
690			/*
691			 * Take the refcount for the first node and go ahead
692			 * and lock this. Note that we zero the tlb_mtx
693			 * structure, since 0xdeadc0de flips the right bits
694			 * for the code to think that this mutex has already
695			 * been initialized. :-(
696			 */
697			SLIST_INIT(&tlb->tlb_head);
698			refcount_init(&tlb->tlb_refcnt, 1);
699			memset(&tlb->tlb_mtx, 0, sizeof(struct mtx));
700			TCPID_BUCKET_LOCK_INIT(tlb);
701			TCPID_BUCKET_LOCK(tlb);
702			bucket_locked = true;
703
704#define	FREE_NEW_TLB()	do {				\
705	TCPID_BUCKET_LOCK_DESTROY(tlb);			\
706	uma_zfree(tcp_log_bucket_zone, tlb);		\
707	bucket_locked = false;				\
708	tlb = NULL;					\
709} while (0)
710			/*
711			 * Relock the INP and make sure we are still
712			 * unassigned.
713			 */
714			INP_WLOCK(inp);
715			RECHECK_INP_CLEAN(FREE_NEW_TLB());
716			if (tp->t_lib != NULL) {
717				FREE_NEW_TLB();
718				goto restart;
719			}
720
721			/* Add the new bucket to the tree. */
722			tmp_tlb = RB_INSERT(tcp_log_id_tree, &tcp_log_id_head,
723			    tlb);
724			KASSERT(tmp_tlb == NULL,
725			    ("%s: Unexpected conflicting bucket (%p) while "
726			    "adding new bucket (%p)", __func__, tmp_tlb, tlb));
727
728			/*
729			 * If we found a conflicting bucket, free the new
730			 * one we made and fall through to use the existing
731			 * bucket.
732			 */
733			if (tmp_tlb != NULL) {
734				FREE_NEW_TLB();
735				INP_WUNLOCK(inp);
736			}
737#undef	FREE_NEW_TLB
738		}
739
740		/* If we found an existing bucket, use it. */
741		if (tmp_tlb != NULL) {
742			tlb = tmp_tlb;
743			TCPID_BUCKET_LOCK(tlb);
744			bucket_locked = true;
745
746			/*
747			 * Relock the INP and make sure we are still
748			 * unassigned.
749			 */
750			INP_UNLOCK_ASSERT(inp);
751			INP_WLOCK(inp);
752			RECHECK_INP();
753			if (tp->t_lib != NULL) {
754				TCPID_BUCKET_UNLOCK(tlb);
755				tlb = NULL;
756				goto restart;
757			}
758
759			/* Take a reference on the bucket. */
760			TCPID_BUCKET_REF(tlb);
761		}
762
763		tcp_log_grow_tlb(tlb->tlb_id, tp);
764
765		/* Add the new node to the list. */
766		SLIST_INSERT_HEAD(&tlb->tlb_head, tln, tln_list);
767		tp->t_lib = tlb;
768		tp->t_lin = tln;
769		tln = NULL;
770	}
771
772	rv = 0;
773
774done:
775	/* Unlock things, as needed, and return. */
776	INP_WUNLOCK(inp);
777done_noinp:
778	INP_UNLOCK_ASSERT(inp);
779	if (bucket_locked) {
780		TCPID_BUCKET_LOCK_ASSERT(tlb);
781		TCPID_BUCKET_UNLOCK(tlb);
782	} else if (tlb != NULL)
783		TCPID_BUCKET_UNLOCK_ASSERT(tlb);
784	if (tree_locked == TREE_WLOCKED) {
785		TCPID_TREE_WLOCK_ASSERT();
786		TCPID_TREE_WUNLOCK();
787	} else if (tree_locked == TREE_RLOCKED) {
788		TCPID_TREE_RLOCK_ASSERT();
789		TCPID_TREE_RUNLOCK();
790	} else
791		TCPID_TREE_UNLOCK_ASSERT();
792	if (tln != NULL)
793		uma_zfree(tcp_log_node_zone, tln);
794	return (rv);
795}
796
797/*
798 * Get the TCP log ID for a TCPCB.
799 * Called with INPCB locked.
800 * 'buf' must point to a buffer that is at least TCP_LOG_ID_LEN bytes long.
801 * Returns number of bytes copied.
802 */
803size_t
804tcp_log_get_id(struct tcpcb *tp, char *buf)
805{
806	size_t len;
807
808	INP_LOCK_ASSERT(tp->t_inpcb);
809	if (tp->t_lib != NULL) {
810		len = strlcpy(buf, tp->t_lib->tlb_id, TCP_LOG_ID_LEN);
811		KASSERT(len < TCP_LOG_ID_LEN,
812		    ("%s:%d: tp->t_lib->tlb_id too long (%zu)",
813		    __func__, __LINE__, len));
814	} else {
815		*buf = '\0';
816		len = 0;
817	}
818	return (len);
819}
820
821/*
822 * Get number of connections with the same log ID.
823 * Log ID is taken from given TCPCB.
824 * Called with INPCB locked.
825 */
826u_int
827tcp_log_get_id_cnt(struct tcpcb *tp)
828{
829
830	INP_WLOCK_ASSERT(tp->t_inpcb);
831	return ((tp->t_lib == NULL) ? 0 : tp->t_lib->tlb_refcnt);
832}
833
834#ifdef TCPLOG_DEBUG_RINGBUF
835/*
836 * Functions/macros to increment/decrement reference count for a log
837 * entry. This should catch when we do a double-free/double-remove or
838 * a double-add.
839 */
840static inline void
841_tcp_log_entry_refcnt_add(struct tcp_log_mem *log_entry, const char *func,
842    int line)
843{
844	int refcnt;
845
846	refcnt = atomic_fetchadd_int(&log_entry->tlm_refcnt, 1);
847	if (refcnt != 0)
848		panic("%s:%d: log_entry(%p)->tlm_refcnt is %d (expected 0)",
849		    func, line, log_entry, refcnt);
850}
851#define	tcp_log_entry_refcnt_add(l)	\
852    _tcp_log_entry_refcnt_add((l), __func__, __LINE__)
853
854static inline void
855_tcp_log_entry_refcnt_rem(struct tcp_log_mem *log_entry, const char *func,
856    int line)
857{
858	int refcnt;
859
860	refcnt = atomic_fetchadd_int(&log_entry->tlm_refcnt, -1);
861	if (refcnt != 1)
862		panic("%s:%d: log_entry(%p)->tlm_refcnt is %d (expected 1)",
863		    func, line, log_entry, refcnt);
864}
865#define	tcp_log_entry_refcnt_rem(l)	\
866    _tcp_log_entry_refcnt_rem((l), __func__, __LINE__)
867
868#else /* !TCPLOG_DEBUG_RINGBUF */
869
870#define	tcp_log_entry_refcnt_add(l)
871#define	tcp_log_entry_refcnt_rem(l)
872
873#endif
874
875/*
876 * Cleanup after removing a log entry, but only decrement the count if we
877 * are running INVARIANTS.
878 */
879static inline void
880tcp_log_free_log_common(struct tcp_log_mem *log_entry, int *count __unused)
881{
882
883	uma_zfree(tcp_log_zone, log_entry);
884#ifdef INVARIANTS
885	(*count)--;
886	KASSERT(*count >= 0,
887	    ("%s: count unexpectedly negative", __func__));
888#endif
889}
890
891static void
892tcp_log_free_entries(struct tcp_log_stailq *head, int *count)
893{
894	struct tcp_log_mem *log_entry;
895
896	/* Free the entries. */
897	while ((log_entry = STAILQ_FIRST(head)) != NULL) {
898		STAILQ_REMOVE_HEAD(head, tlm_queue);
899		tcp_log_entry_refcnt_rem(log_entry);
900		tcp_log_free_log_common(log_entry, count);
901	}
902}
903
904/* Cleanup after removing a log entry. */
905static inline void
906tcp_log_remove_log_cleanup(struct tcpcb *tp, struct tcp_log_mem *log_entry)
907{
908	uma_zfree(tcp_log_zone, log_entry);
909	tp->t_lognum--;
910	KASSERT(tp->t_lognum >= 0,
911	    ("%s: tp->t_lognum unexpectedly negative", __func__));
912}
913
914/* Remove a log entry from the head of a list. */
915static inline void
916tcp_log_remove_log_head(struct tcpcb *tp, struct tcp_log_mem *log_entry)
917{
918
919	KASSERT(log_entry == STAILQ_FIRST(&tp->t_logs),
920	    ("%s: attempt to remove non-HEAD log entry", __func__));
921	STAILQ_REMOVE_HEAD(&tp->t_logs, tlm_queue);
922	tcp_log_entry_refcnt_rem(log_entry);
923	tcp_log_remove_log_cleanup(tp, log_entry);
924}
925
926#ifdef TCPLOG_DEBUG_RINGBUF
927/*
928 * Initialize the log entry's reference count, which we want to
929 * survive allocations.
930 */
931static int
932tcp_log_zone_init(void *mem, int size, int flags __unused)
933{
934	struct tcp_log_mem *tlm;
935
936	KASSERT(size >= sizeof(struct tcp_log_mem),
937	    ("%s: unexpectedly short (%d) allocation", __func__, size));
938	tlm = (struct tcp_log_mem *)mem;
939	tlm->tlm_refcnt = 0;
940	return (0);
941}
942
943/*
944 * Double check that the refcnt is zero on allocation and return.
945 */
946static int
947tcp_log_zone_ctor(void *mem, int size, void *args __unused, int flags __unused)
948{
949	struct tcp_log_mem *tlm;
950
951	KASSERT(size >= sizeof(struct tcp_log_mem),
952	    ("%s: unexpectedly short (%d) allocation", __func__, size));
953	tlm = (struct tcp_log_mem *)mem;
954	if (tlm->tlm_refcnt != 0)
955		panic("%s:%d: tlm(%p)->tlm_refcnt is %d (expected 0)",
956		    __func__, __LINE__, tlm, tlm->tlm_refcnt);
957	return (0);
958}
959
960static void
961tcp_log_zone_dtor(void *mem, int size, void *args __unused)
962{
963	struct tcp_log_mem *tlm;
964
965	KASSERT(size >= sizeof(struct tcp_log_mem),
966	    ("%s: unexpectedly short (%d) allocation", __func__, size));
967	tlm = (struct tcp_log_mem *)mem;
968	if (tlm->tlm_refcnt != 0)
969		panic("%s:%d: tlm(%p)->tlm_refcnt is %d (expected 0)",
970		    __func__, __LINE__, tlm, tlm->tlm_refcnt);
971}
972#endif /* TCPLOG_DEBUG_RINGBUF */
973
974/* Do global initialization. */
975void
976tcp_log_init(void)
977{
978
979	tcp_log_zone = uma_zcreate("tcp_log", sizeof(struct tcp_log_mem),
980#ifdef TCPLOG_DEBUG_RINGBUF
981	    tcp_log_zone_ctor, tcp_log_zone_dtor, tcp_log_zone_init,
982#else
983	    NULL, NULL, NULL,
984#endif
985	    NULL, UMA_ALIGN_PTR, 0);
986	(void)uma_zone_set_max(tcp_log_zone, TCP_LOG_BUF_DEFAULT_GLOBAL_LIMIT);
987	tcp_log_bucket_zone = uma_zcreate("tcp_log_bucket",
988	    sizeof(struct tcp_log_id_bucket), NULL, NULL, NULL, NULL,
989	    UMA_ALIGN_PTR, 0);
990	tcp_log_node_zone = uma_zcreate("tcp_log_node",
991	    sizeof(struct tcp_log_id_node), NULL, NULL, NULL, NULL,
992	    UMA_ALIGN_PTR, 0);
993#ifdef TCPLOG_DEBUG_COUNTERS
994	tcp_log_queued = counter_u64_alloc(M_WAITOK);
995	tcp_log_que_fail1 = counter_u64_alloc(M_WAITOK);
996	tcp_log_que_fail2 = counter_u64_alloc(M_WAITOK);
997	tcp_log_que_fail3 = counter_u64_alloc(M_WAITOK);
998	tcp_log_que_fail4 = counter_u64_alloc(M_WAITOK);
999	tcp_log_que_fail5 = counter_u64_alloc(M_WAITOK);
1000	tcp_log_que_copyout = counter_u64_alloc(M_WAITOK);
1001	tcp_log_que_read = counter_u64_alloc(M_WAITOK);
1002	tcp_log_que_freed = counter_u64_alloc(M_WAITOK);
1003#endif
1004
1005	rw_init_flags(&tcp_id_tree_lock, "TCP ID tree", RW_NEW);
1006	mtx_init(&tcp_log_expireq_mtx, "TCP log expireq", NULL, MTX_DEF);
1007	callout_init(&tcp_log_expireq_callout, 1);
1008}
1009
1010/* Do per-TCPCB initialization. */
1011void
1012tcp_log_tcpcbinit(struct tcpcb *tp)
1013{
1014
1015	/* A new TCPCB should start out zero-initialized. */
1016	STAILQ_INIT(&tp->t_logs);
1017
1018	/*
1019	 * If we are doing auto-capturing, figure out whether we will capture
1020	 * this session.
1021	 */
1022	if (tcp_log_selectauto()) {
1023		tp->t_logstate = tcp_log_auto_mode;
1024		tp->t_flags2 |= TF2_LOG_AUTO;
1025	}
1026}
1027
1028
1029/* Remove entries */
1030static void
1031tcp_log_expire(void *unused __unused)
1032{
1033	struct tcp_log_id_bucket *tlb;
1034	struct tcp_log_id_node *tln;
1035	sbintime_t expiry_limit;
1036	int tree_locked;
1037
1038	TCPLOG_EXPIREQ_LOCK();
1039	if (callout_pending(&tcp_log_expireq_callout)) {
1040		/* Callout was reset. */
1041		TCPLOG_EXPIREQ_UNLOCK();
1042		return;
1043	}
1044
1045	/*
1046	 * Process entries until we reach one that expires too far in the
1047	 * future. Look one second in the future.
1048	 */
1049	expiry_limit = getsbinuptime() + SBT_1S;
1050	tree_locked = TREE_UNLOCKED;
1051
1052	while ((tln = STAILQ_FIRST(&tcp_log_expireq_head)) != NULL &&
1053	    tln->tln_expiretime <= expiry_limit) {
1054		if (!callout_active(&tcp_log_expireq_callout)) {
1055			/*
1056			 * Callout was stopped. I guess we should
1057			 * just quit at this point.
1058			 */
1059			TCPLOG_EXPIREQ_UNLOCK();
1060			return;
1061		}
1062
1063		/*
1064		 * Remove the node from the head of the list and unlock
1065		 * the list. Change the expiry time to SBT_MAX as a signal
1066		 * to other threads that we now own this.
1067		 */
1068		STAILQ_REMOVE_HEAD(&tcp_log_expireq_head, tln_expireq);
1069		tln->tln_expiretime = SBT_MAX;
1070		TCPLOG_EXPIREQ_UNLOCK();
1071
1072		/*
1073		 * Remove the node from the bucket.
1074		 */
1075		tlb = tln->tln_bucket;
1076		TCPID_BUCKET_LOCK(tlb);
1077		if (tcp_log_remove_id_node(NULL, NULL, tlb, tln, &tree_locked)) {
1078			tcp_log_id_validate_tree_lock(tree_locked);
1079			if (tree_locked == TREE_WLOCKED)
1080				TCPID_TREE_WUNLOCK();
1081			else
1082				TCPID_TREE_RUNLOCK();
1083			tree_locked = TREE_UNLOCKED;
1084		}
1085
1086		/* Drop the INP reference. */
1087		INP_WLOCK(tln->tln_inp);
1088		if (!in_pcbrele_wlocked(tln->tln_inp))
1089			INP_WUNLOCK(tln->tln_inp);
1090
1091		/* Free the log records. */
1092		tcp_log_free_entries(&tln->tln_entries, &tln->tln_count);
1093
1094		/* Free the node. */
1095		uma_zfree(tcp_log_node_zone, tln);
1096
1097		/* Relock the expiry queue. */
1098		TCPLOG_EXPIREQ_LOCK();
1099	}
1100
1101	/*
1102	 * We've expired all the entries we can. Do we need to reschedule
1103	 * ourselves?
1104	 */
1105	callout_deactivate(&tcp_log_expireq_callout);
1106	if (tln != NULL) {
1107		/*
1108		 * Get max(now + TCP_LOG_EXPIRE_INTVL, tln->tln_expiretime) and
1109		 * set the next callout to that. (This helps ensure we generally
1110		 * run the callout no more often than desired.)
1111		 */
1112		expiry_limit = getsbinuptime() + TCP_LOG_EXPIRE_INTVL;
1113		if (expiry_limit < tln->tln_expiretime)
1114			expiry_limit = tln->tln_expiretime;
1115		callout_reset_sbt(&tcp_log_expireq_callout, expiry_limit,
1116		    SBT_1S, tcp_log_expire, NULL, C_ABSOLUTE);
1117	}
1118
1119	/* We're done. */
1120	TCPLOG_EXPIREQ_UNLOCK();
1121	return;
1122}
1123
1124/*
1125 * Move log data from the TCPCB to a new node. This will reset the TCPCB log
1126 * entries and log count; however, it will not touch other things from the
1127 * TCPCB (e.g. t_lin, t_lib).
1128 *
1129 * NOTE: Must hold a lock on the INP.
1130 */
1131static void
1132tcp_log_move_tp_to_node(struct tcpcb *tp, struct tcp_log_id_node *tln)
1133{
1134
1135	INP_WLOCK_ASSERT(tp->t_inpcb);
1136
1137	tln->tln_ie = tp->t_inpcb->inp_inc.inc_ie;
1138	if (tp->t_inpcb->inp_inc.inc_flags & INC_ISIPV6)
1139		tln->tln_af = AF_INET6;
1140	else
1141		tln->tln_af = AF_INET;
1142	tln->tln_entries = tp->t_logs;
1143	tln->tln_count = tp->t_lognum;
1144	tln->tln_bucket = tp->t_lib;
1145
1146	/* Clear information from the PCB. */
1147	STAILQ_INIT(&tp->t_logs);
1148	tp->t_lognum = 0;
1149}
1150
1151/* Do per-TCPCB cleanup */
1152void
1153tcp_log_tcpcbfini(struct tcpcb *tp)
1154{
1155	struct tcp_log_id_node *tln, *tln_first;
1156	struct tcp_log_mem *log_entry;
1157	sbintime_t callouttime;
1158
1159	INP_WLOCK_ASSERT(tp->t_inpcb);
1160
1161	/*
1162	 * If we were gathering packets to be automatically dumped, try to do
1163	 * it now. If this succeeds, the log information in the TCPCB will be
1164	 * cleared. Otherwise, we'll handle the log information as we do
1165	 * for other states.
1166	 */
1167	switch(tp->t_logstate) {
1168	case TCP_LOG_STATE_HEAD_AUTO:
1169		(void)tcp_log_dump_tp_logbuf(tp, "auto-dumped from head",
1170		    M_NOWAIT, false);
1171		break;
1172	case TCP_LOG_STATE_TAIL_AUTO:
1173		(void)tcp_log_dump_tp_logbuf(tp, "auto-dumped from tail",
1174		    M_NOWAIT, false);
1175		break;
1176	case TCP_LOG_STATE_CONTINUAL:
1177		(void)tcp_log_dump_tp_logbuf(tp, "auto-dumped from continual",
1178		    M_NOWAIT, false);
1179		break;
1180	}
1181
1182	/*
1183	 * There are two ways we could keep logs: per-socket or per-ID. If
1184	 * we are tracking logs with an ID, then the logs survive the
1185	 * destruction of the TCPCB.
1186	 *
1187	 * If the TCPCB is associated with an ID node, move the logs from the
1188	 * TCPCB to the ID node. In theory, this is safe, for reasons which I
1189	 * will now explain for my own benefit when I next need to figure out
1190	 * this code. :-)
1191	 *
1192	 * We own the INP lock. Therefore, no one else can change the contents
1193	 * of this node (Rule C). Further, no one can remove this node from
1194	 * the bucket while we hold the lock (Rule D). Basically, no one can
1195	 * mess with this node. That leaves two states in which we could be:
1196	 *
1197	 * 1. Another thread is currently waiting to acquire the INP lock, with
1198	 *    plans to do something with this node. When we drop the INP lock,
1199	 *    they will have a chance to do that. They will recheck the
1200	 *    tln_closed field (see note to Rule C) and then acquire the
1201	 *    bucket lock before proceeding further.
1202	 *
1203	 * 2. Another thread will try to acquire a lock at some point in the
1204	 *    future. If they try to acquire a lock before we set the
1205	 *    tln_closed field, they will follow state #1. If they try to
1206	 *    acquire a lock after we set the tln_closed field, they will be
1207	 *    able to make changes to the node, at will, following Rule C.
1208	 *
1209	 * Therefore, we currently own this node and can make any changes
1210	 * we want. But, as soon as we set the tln_closed field to true, we
1211	 * have effectively dropped our lock on the node. (For this reason, we
1212	 * also need to make sure our writes are ordered correctly. An atomic
1213	 * operation with "release" semantics should be sufficient.)
1214	 */
1215
1216	if (tp->t_lin != NULL) {
1217		/* Copy the relevant information to the log entry. */
1218		tln = tp->t_lin;
1219		KASSERT(tln->tln_inp == tp->t_inpcb,
1220		    ("%s: Mismatched inp (tln->tln_inp=%p, tp->t_inpcb=%p)",
1221		    __func__, tln->tln_inp, tp->t_inpcb));
1222		tcp_log_move_tp_to_node(tp, tln);
1223
1224		/* Clear information from the PCB. */
1225		tp->t_lin = NULL;
1226		tp->t_lib = NULL;
1227
1228		/*
1229		 * Take a reference on the INP. This ensures that the INP
1230		 * remains valid while the node is on the expiry queue. This
1231		 * ensures the INP is valid for other threads that may be
1232		 * racing to lock this node when we move it to the expire
1233		 * queue.
1234		 */
1235		in_pcbref(tp->t_inpcb);
1236
1237		/*
1238		 * Store the entry on the expiry list. The exact behavior
1239		 * depends on whether we have entries to keep. If so, we
1240		 * put the entry at the tail of the list and expire in
1241		 * TCP_LOG_EXPIRE_TIME. Otherwise, we expire "now" and put
1242		 * the entry at the head of the list. (Handling the cleanup
1243		 * via the expiry timer lets us avoid locking messy-ness here.)
1244		 */
1245		tln->tln_expiretime = getsbinuptime();
1246		TCPLOG_EXPIREQ_LOCK();
1247		if (tln->tln_count) {
1248			tln->tln_expiretime += TCP_LOG_EXPIRE_TIME;
1249			if (STAILQ_EMPTY(&tcp_log_expireq_head) &&
1250			    !callout_active(&tcp_log_expireq_callout)) {
1251				/*
1252				 * We are adding the first entry and a callout
1253				 * is not currently scheduled; therefore, we
1254				 * need to schedule one.
1255				 */
1256				callout_reset_sbt(&tcp_log_expireq_callout,
1257				    tln->tln_expiretime, SBT_1S, tcp_log_expire,
1258				    NULL, C_ABSOLUTE);
1259			}
1260			STAILQ_INSERT_TAIL(&tcp_log_expireq_head, tln,
1261			    tln_expireq);
1262		} else {
1263			callouttime = tln->tln_expiretime +
1264			    TCP_LOG_EXPIRE_INTVL;
1265			tln_first = STAILQ_FIRST(&tcp_log_expireq_head);
1266
1267			if ((tln_first == NULL ||
1268			    callouttime < tln_first->tln_expiretime) &&
1269			    (callout_pending(&tcp_log_expireq_callout) ||
1270			    !callout_active(&tcp_log_expireq_callout))) {
1271				/*
1272				 * The list is empty, or we want to run the
1273				 * expire code before the first entry's timer
1274				 * fires. Also, we are in a case where a callout
1275				 * is not actively running. We want to reset
1276				 * the callout to occur sooner.
1277				 */
1278				callout_reset_sbt(&tcp_log_expireq_callout,
1279				    callouttime, SBT_1S, tcp_log_expire, NULL,
1280				    C_ABSOLUTE);
1281			}
1282
1283			/*
1284			 * Insert to the head, or just after the head, as
1285			 * appropriate. (This might result in small
1286			 * mis-orderings as a bunch of "expire now" entries
1287			 * gather at the start of the list, but that should
1288			 * not produce big problems, since the expire timer
1289			 * will walk through all of them.)
1290			 */
1291			if (tln_first == NULL ||
1292			    tln->tln_expiretime < tln_first->tln_expiretime)
1293				STAILQ_INSERT_HEAD(&tcp_log_expireq_head, tln,
1294				    tln_expireq);
1295			else
1296				STAILQ_INSERT_AFTER(&tcp_log_expireq_head,
1297				    tln_first, tln, tln_expireq);
1298		}
1299		TCPLOG_EXPIREQ_UNLOCK();
1300
1301		/*
1302		 * We are done messing with the tln. After this point, we
1303		 * can't touch it. (Note that the "release" semantics should
1304		 * be included with the TCPLOG_EXPIREQ_UNLOCK() call above.
1305		 * Therefore, they should be unnecessary here. However, it
1306		 * seems like a good idea to include them anyway, since we
1307		 * really are releasing a lock here.)
1308		 */
1309		atomic_store_rel_int(&tln->tln_closed, 1);
1310	} else {
1311		/* Remove log entries. */
1312		while ((log_entry = STAILQ_FIRST(&tp->t_logs)) != NULL)
1313			tcp_log_remove_log_head(tp, log_entry);
1314		KASSERT(tp->t_lognum == 0,
1315		    ("%s: After freeing entries, tp->t_lognum=%d (expected 0)",
1316			__func__, tp->t_lognum));
1317	}
1318
1319	/*
1320	 * Change the log state to off (just in case anything tries to sneak
1321	 * in a last-minute log).
1322	 */
1323	tp->t_logstate = TCP_LOG_STATE_OFF;
1324}
1325
1326/*
1327 * This logs an event for a TCP socket. Normally, this is called via
1328 * TCP_LOG_EVENT or TCP_LOG_EVENT_VERBOSE. See the documentation for
1329 * TCP_LOG_EVENT().
1330 */
1331
1332struct tcp_log_buffer *
1333tcp_log_event_(struct tcpcb *tp, struct tcphdr *th, struct sockbuf *rxbuf,
1334    struct sockbuf *txbuf, uint8_t eventid, int errornum, uint32_t len,
1335    union tcp_log_stackspecific *stackinfo, int th_hostorder,
1336    const char *output_caller, const char *func, int line, const struct timeval *itv)
1337{
1338	struct tcp_log_mem *log_entry;
1339	struct tcp_log_buffer *log_buf;
1340	int attempt_count = 0;
1341	struct tcp_log_verbose *log_verbose;
1342	uint32_t logsn;
1343
1344	KASSERT((func == NULL && line == 0) || (func != NULL && line > 0),
1345	    ("%s called with inconsistent func (%p) and line (%d) arguments",
1346		__func__, func, line));
1347
1348	INP_WLOCK_ASSERT(tp->t_inpcb);
1349
1350	KASSERT(tp->t_logstate == TCP_LOG_STATE_HEAD ||
1351	    tp->t_logstate == TCP_LOG_STATE_TAIL ||
1352	    tp->t_logstate == TCP_LOG_STATE_CONTINUAL ||
1353	    tp->t_logstate == TCP_LOG_STATE_HEAD_AUTO ||
1354	    tp->t_logstate == TCP_LOG_STATE_TAIL_AUTO,
1355	    ("%s called with unexpected tp->t_logstate (%d)", __func__,
1356		tp->t_logstate));
1357
1358	/*
1359	 * Get the serial number. We do this early so it will
1360	 * increment even if we end up skipping the log entry for some
1361	 * reason.
1362	 */
1363	logsn = tp->t_logsn++;
1364
1365	/*
1366	 * Can we get a new log entry? If so, increment the lognum counter
1367	 * here.
1368	 */
1369retry:
1370	if (tp->t_lognum < tcp_log_session_limit) {
1371		if ((log_entry = uma_zalloc(tcp_log_zone, M_NOWAIT)) != NULL)
1372			tp->t_lognum++;
1373	} else
1374		log_entry = NULL;
1375
1376	/* Do we need to try to reuse? */
1377	if (log_entry == NULL) {
1378		/*
1379		 * Sacrifice auto-logged sessions without a log ID if
1380		 * tcp_log_auto_all is false. (If they don't have a log
1381		 * ID by now, it is probable that either they won't get one
1382		 * or we are resource-constrained.)
1383		 */
1384		if (tp->t_lib == NULL && (tp->t_flags2 & TF2_LOG_AUTO) &&
1385		    !tcp_log_auto_all) {
1386			if (tcp_log_state_change(tp, TCP_LOG_STATE_CLEAR)) {
1387#ifdef INVARIANTS
1388				panic("%s:%d: tcp_log_state_change() failed "
1389				    "to set tp %p to TCP_LOG_STATE_CLEAR",
1390				    __func__, __LINE__, tp);
1391#endif
1392				tp->t_logstate = TCP_LOG_STATE_OFF;
1393			}
1394			return (NULL);
1395		}
1396		/*
1397		 * If we are in TCP_LOG_STATE_HEAD_AUTO state, try to dump
1398		 * the buffers. If successful, deactivate tracing. Otherwise,
1399		 * leave it active so we will retry.
1400		 */
1401		if (tp->t_logstate == TCP_LOG_STATE_HEAD_AUTO &&
1402		    !tcp_log_dump_tp_logbuf(tp, "auto-dumped from head",
1403		    M_NOWAIT, false)) {
1404			tp->t_logstate = TCP_LOG_STATE_OFF;
1405			return(NULL);
1406		} else if ((tp->t_logstate == TCP_LOG_STATE_CONTINUAL) &&
1407		    !tcp_log_dump_tp_logbuf(tp, "auto-dumped from continual",
1408		    M_NOWAIT, false)) {
1409			if (attempt_count == 0) {
1410				attempt_count++;
1411				goto retry;
1412			}
1413#ifdef TCPLOG_DEBUG_COUNTERS
1414			counter_u64_add(tcp_log_que_fail4, 1);
1415#endif
1416			return(NULL);
1417		} else if (tp->t_logstate == TCP_LOG_STATE_HEAD_AUTO)
1418			return(NULL);
1419
1420		/* If in HEAD state, just deactivate the tracing and return. */
1421		if (tp->t_logstate == TCP_LOG_STATE_HEAD) {
1422			tp->t_logstate = TCP_LOG_STATE_OFF;
1423			return(NULL);
1424		}
1425
1426		/*
1427		 * Get a buffer to reuse. If that fails, just give up.
1428		 * (We can't log anything without a buffer in which to
1429		 * put it.)
1430		 *
1431		 * Note that we don't change the t_lognum counter
1432		 * here. Because we are re-using the buffer, the total
1433		 * number won't change.
1434		 */
1435		if ((log_entry = STAILQ_FIRST(&tp->t_logs)) == NULL)
1436			return(NULL);
1437		STAILQ_REMOVE_HEAD(&tp->t_logs, tlm_queue);
1438		tcp_log_entry_refcnt_rem(log_entry);
1439	}
1440
1441	KASSERT(log_entry != NULL,
1442	    ("%s: log_entry unexpectedly NULL", __func__));
1443
1444	/* Extract the log buffer and verbose buffer pointers. */
1445	log_buf = &log_entry->tlm_buf;
1446	log_verbose = &log_entry->tlm_v;
1447
1448	/* Basic entries. */
1449	if (itv == NULL)
1450		getmicrouptime(&log_buf->tlb_tv);
1451	else
1452		memcpy(&log_buf->tlb_tv, itv, sizeof(struct timeval));
1453	log_buf->tlb_ticks = ticks;
1454	log_buf->tlb_sn = logsn;
1455	log_buf->tlb_stackid = tp->t_fb->tfb_id;
1456	log_buf->tlb_eventid = eventid;
1457	log_buf->tlb_eventflags = 0;
1458	log_buf->tlb_errno = errornum;
1459
1460	/* Socket buffers */
1461	if (rxbuf != NULL) {
1462		log_buf->tlb_eventflags |= TLB_FLAG_RXBUF;
1463		log_buf->tlb_rxbuf.tls_sb_acc = rxbuf->sb_acc;
1464		log_buf->tlb_rxbuf.tls_sb_ccc = rxbuf->sb_ccc;
1465		log_buf->tlb_rxbuf.tls_sb_spare = 0;
1466	}
1467	if (txbuf != NULL) {
1468		log_buf->tlb_eventflags |= TLB_FLAG_TXBUF;
1469		log_buf->tlb_txbuf.tls_sb_acc = txbuf->sb_acc;
1470		log_buf->tlb_txbuf.tls_sb_ccc = txbuf->sb_ccc;
1471		log_buf->tlb_txbuf.tls_sb_spare = 0;
1472	}
1473	/* Copy values from tp to the log entry. */
1474#define	COPY_STAT(f)	log_buf->tlb_ ## f = tp->f
1475#define	COPY_STAT_T(f)	log_buf->tlb_ ## f = tp->t_ ## f
1476	COPY_STAT_T(state);
1477	COPY_STAT_T(starttime);
1478	COPY_STAT(iss);
1479	COPY_STAT_T(flags);
1480	COPY_STAT(snd_una);
1481	COPY_STAT(snd_max);
1482	COPY_STAT(snd_cwnd);
1483	COPY_STAT(snd_nxt);
1484	COPY_STAT(snd_recover);
1485	COPY_STAT(snd_wnd);
1486	COPY_STAT(snd_ssthresh);
1487	COPY_STAT_T(srtt);
1488	COPY_STAT_T(rttvar);
1489	COPY_STAT(rcv_up);
1490	COPY_STAT(rcv_adv);
1491	COPY_STAT(rcv_nxt);
1492	COPY_STAT(sack_newdata);
1493	COPY_STAT(rcv_wnd);
1494	COPY_STAT_T(dupacks);
1495	COPY_STAT_T(segqlen);
1496	COPY_STAT(snd_numholes);
1497	COPY_STAT(snd_scale);
1498	COPY_STAT(rcv_scale);
1499#undef COPY_STAT
1500#undef COPY_STAT_T
1501	log_buf->tlb_flex1 = 0;
1502	log_buf->tlb_flex2 = 0;
1503	/* Copy stack-specific info. */
1504	if (stackinfo != NULL) {
1505		memcpy(&log_buf->tlb_stackinfo, stackinfo,
1506		    sizeof(log_buf->tlb_stackinfo));
1507		log_buf->tlb_eventflags |= TLB_FLAG_STACKINFO;
1508	}
1509
1510	/* The packet */
1511	log_buf->tlb_len = len;
1512	if (th) {
1513		int optlen;
1514
1515		log_buf->tlb_eventflags |= TLB_FLAG_HDR;
1516		log_buf->tlb_th = *th;
1517		if (th_hostorder)
1518			tcp_fields_to_net(&log_buf->tlb_th);
1519		optlen = (th->th_off << 2) - sizeof (struct tcphdr);
1520		if (optlen > 0)
1521			memcpy(log_buf->tlb_opts, th + 1, optlen);
1522	}
1523
1524	/* Verbose information */
1525	if (func != NULL) {
1526		log_buf->tlb_eventflags |= TLB_FLAG_VERBOSE;
1527		if (output_caller != NULL)
1528			strlcpy(log_verbose->tlv_snd_frm, output_caller,
1529			    TCP_FUNC_LEN);
1530		else
1531			*log_verbose->tlv_snd_frm = 0;
1532		strlcpy(log_verbose->tlv_trace_func, func, TCP_FUNC_LEN);
1533		log_verbose->tlv_trace_line = line;
1534	}
1535
1536	/* Insert the new log at the tail. */
1537	STAILQ_INSERT_TAIL(&tp->t_logs, log_entry, tlm_queue);
1538	tcp_log_entry_refcnt_add(log_entry);
1539	return (log_buf);
1540}
1541
1542/*
1543 * Change the logging state for a TCPCB. Returns 0 on success or an
1544 * error code on failure.
1545 */
1546int
1547tcp_log_state_change(struct tcpcb *tp, int state)
1548{
1549	struct tcp_log_mem *log_entry;
1550
1551	INP_WLOCK_ASSERT(tp->t_inpcb);
1552	switch(state) {
1553	case TCP_LOG_STATE_CLEAR:
1554		while ((log_entry = STAILQ_FIRST(&tp->t_logs)) != NULL)
1555			tcp_log_remove_log_head(tp, log_entry);
1556		/* Fall through */
1557
1558	case TCP_LOG_STATE_OFF:
1559		tp->t_logstate = TCP_LOG_STATE_OFF;
1560		break;
1561
1562	case TCP_LOG_STATE_TAIL:
1563	case TCP_LOG_STATE_HEAD:
1564	case TCP_LOG_STATE_CONTINUAL:
1565	case TCP_LOG_STATE_HEAD_AUTO:
1566	case TCP_LOG_STATE_TAIL_AUTO:
1567		tp->t_logstate = state;
1568		break;
1569
1570	default:
1571		return (EINVAL);
1572	}
1573
1574	tp->t_flags2 &= ~(TF2_LOG_AUTO);
1575
1576	return (0);
1577}
1578
1579/* If tcp_drain() is called, flush half the log entries. */
1580void
1581tcp_log_drain(struct tcpcb *tp)
1582{
1583	struct tcp_log_mem *log_entry, *next;
1584	int target, skip;
1585
1586	INP_WLOCK_ASSERT(tp->t_inpcb);
1587	if ((target = tp->t_lognum / 2) == 0)
1588		return;
1589
1590	/*
1591	 * If we are logging the "head" packets, we want to discard
1592	 * from the tail of the queue. Otherwise, we want to discard
1593	 * from the head.
1594	 */
1595	if (tp->t_logstate == TCP_LOG_STATE_HEAD ||
1596	    tp->t_logstate == TCP_LOG_STATE_HEAD_AUTO) {
1597		skip = tp->t_lognum - target;
1598		STAILQ_FOREACH(log_entry, &tp->t_logs, tlm_queue)
1599			if (!--skip)
1600				break;
1601		KASSERT(log_entry != NULL,
1602		    ("%s: skipped through all entries!", __func__));
1603		if (log_entry == NULL)
1604			return;
1605		while ((next = STAILQ_NEXT(log_entry, tlm_queue)) != NULL) {
1606			STAILQ_REMOVE_AFTER(&tp->t_logs, log_entry, tlm_queue);
1607			tcp_log_entry_refcnt_rem(next);
1608			tcp_log_remove_log_cleanup(tp, next);
1609#ifdef INVARIANTS
1610			target--;
1611#endif
1612		}
1613		KASSERT(target == 0,
1614		    ("%s: After removing from tail, target was %d", __func__,
1615			target));
1616	} else if (tp->t_logstate == TCP_LOG_STATE_CONTINUAL) {
1617		(void)tcp_log_dump_tp_logbuf(tp, "auto-dumped from continual",
1618		    M_NOWAIT, false);
1619	} else {
1620		while ((log_entry = STAILQ_FIRST(&tp->t_logs)) != NULL &&
1621		    target--)
1622			tcp_log_remove_log_head(tp, log_entry);
1623		KASSERT(target <= 0,
1624		    ("%s: After removing from head, target was %d", __func__,
1625			target));
1626		KASSERT(tp->t_lognum > 0,
1627		    ("%s: After removing from head, tp->t_lognum was %d",
1628			__func__, target));
1629		KASSERT(log_entry != NULL,
1630		    ("%s: After removing from head, the tailq was empty",
1631			__func__));
1632	}
1633}
1634
1635static inline int
1636tcp_log_copyout(struct sockopt *sopt, void *src, void *dst, size_t len)
1637{
1638
1639	if (sopt->sopt_td != NULL)
1640		return (copyout(src, dst, len));
1641	bcopy(src, dst, len);
1642	return (0);
1643}
1644
1645static int
1646tcp_log_logs_to_buf(struct sockopt *sopt, struct tcp_log_stailq *log_tailqp,
1647    struct tcp_log_buffer **end, int count)
1648{
1649	struct tcp_log_buffer *out_entry;
1650	struct tcp_log_mem *log_entry;
1651	size_t entrysize;
1652	int error;
1653#ifdef INVARIANTS
1654	int orig_count = count;
1655#endif
1656
1657	/* Copy the data out. */
1658	error = 0;
1659	out_entry = (struct tcp_log_buffer *) sopt->sopt_val;
1660	STAILQ_FOREACH(log_entry, log_tailqp, tlm_queue) {
1661		count--;
1662		KASSERT(count >= 0,
1663		    ("%s:%d: Exceeded expected count (%d) processing list %p",
1664		    __func__, __LINE__, orig_count, log_tailqp));
1665
1666#ifdef TCPLOG_DEBUG_COUNTERS
1667		counter_u64_add(tcp_log_que_copyout, 1);
1668#endif
1669
1670		/*
1671		 * Skip copying out the header if it isn't present.
1672		 * Instead, copy out zeros (to ensure we don't leak info).
1673		 * TODO: Make sure we truly do zero everything we don't
1674		 * explicitly set.
1675		 */
1676		if (log_entry->tlm_buf.tlb_eventflags & TLB_FLAG_HDR)
1677			entrysize = sizeof(struct tcp_log_buffer);
1678		else
1679			entrysize = offsetof(struct tcp_log_buffer, tlb_th);
1680		error = tcp_log_copyout(sopt, &log_entry->tlm_buf, out_entry,
1681		    entrysize);
1682		if (error)
1683			break;
1684		if (!(log_entry->tlm_buf.tlb_eventflags & TLB_FLAG_HDR)) {
1685			error = tcp_log_copyout(sopt, zerobuf,
1686			    ((uint8_t *)out_entry) + entrysize,
1687			    sizeof(struct tcp_log_buffer) - entrysize);
1688		}
1689
1690		/*
1691		 * Copy out the verbose bit, if needed. Either way,
1692		 * increment the output pointer the correct amount.
1693		 */
1694		if (log_entry->tlm_buf.tlb_eventflags & TLB_FLAG_VERBOSE) {
1695			error = tcp_log_copyout(sopt, &log_entry->tlm_v,
1696			    out_entry->tlb_verbose,
1697			    sizeof(struct tcp_log_verbose));
1698			if (error)
1699				break;
1700			out_entry = (struct tcp_log_buffer *)
1701			    (((uint8_t *) (out_entry + 1)) +
1702			    sizeof(struct tcp_log_verbose));
1703		} else
1704			out_entry++;
1705	}
1706	*end = out_entry;
1707	KASSERT(error || count == 0,
1708	    ("%s:%d: Less than expected count (%d) processing list %p"
1709	    " (%d remain)", __func__, __LINE__, orig_count,
1710	    log_tailqp, count));
1711
1712	return (error);
1713}
1714
1715/*
1716 * Copy out the buffer. Note that we do incremental copying, so
1717 * sooptcopyout() won't work. However, the goal is to produce the same
1718 * end result as if we copied in the entire user buffer, updated it,
1719 * and then used sooptcopyout() to copy it out.
1720 *
1721 * NOTE: This should be called with a write lock on the PCB; however,
1722 * the function will drop it after it extracts the data from the TCPCB.
1723 */
1724int
1725tcp_log_getlogbuf(struct sockopt *sopt, struct tcpcb *tp)
1726{
1727	struct tcp_log_stailq log_tailq;
1728	struct tcp_log_mem *log_entry, *log_next;
1729	struct tcp_log_buffer *out_entry;
1730	struct inpcb *inp;
1731	size_t outsize, entrysize;
1732	int error, outnum;
1733
1734	INP_WLOCK_ASSERT(tp->t_inpcb);
1735	inp = tp->t_inpcb;
1736
1737	/*
1738	 * Determine which log entries will fit in the buffer. As an
1739	 * optimization, skip this if all the entries will clearly fit
1740	 * in the buffer. (However, get an exact size if we are using
1741	 * INVARIANTS.)
1742	 */
1743#ifndef INVARIANTS
1744	if (sopt->sopt_valsize / (sizeof(struct tcp_log_buffer) +
1745	    sizeof(struct tcp_log_verbose)) >= tp->t_lognum) {
1746		log_entry = STAILQ_LAST(&tp->t_logs, tcp_log_mem, tlm_queue);
1747		log_next = NULL;
1748		outsize = 0;
1749		outnum = tp->t_lognum;
1750	} else {
1751#endif
1752		outsize = outnum = 0;
1753		log_entry = NULL;
1754		STAILQ_FOREACH(log_next, &tp->t_logs, tlm_queue) {
1755			entrysize = sizeof(struct tcp_log_buffer);
1756			if (log_next->tlm_buf.tlb_eventflags &
1757			    TLB_FLAG_VERBOSE)
1758				entrysize += sizeof(struct tcp_log_verbose);
1759			if ((sopt->sopt_valsize - outsize) < entrysize)
1760				break;
1761			outsize += entrysize;
1762			outnum++;
1763			log_entry = log_next;
1764		}
1765		KASSERT(outsize <= sopt->sopt_valsize,
1766		    ("%s: calculated output size (%zu) greater than available"
1767			"space (%zu)", __func__, outsize, sopt->sopt_valsize));
1768#ifndef INVARIANTS
1769	}
1770#endif
1771
1772	/*
1773	 * Copy traditional sooptcopyout() behavior: if sopt->sopt_val
1774	 * is NULL, silently skip the copy. However, in this case, we
1775	 * will leave the list alone and return. Functionally, this
1776	 * gives userspace a way to poll for an approximate buffer
1777	 * size they will need to get the log entries.
1778	 */
1779	if (sopt->sopt_val == NULL) {
1780		INP_WUNLOCK(inp);
1781		if (outsize == 0) {
1782			outsize = outnum * (sizeof(struct tcp_log_buffer) +
1783			    sizeof(struct tcp_log_verbose));
1784		}
1785		if (sopt->sopt_valsize > outsize)
1786			sopt->sopt_valsize = outsize;
1787		return (0);
1788	}
1789
1790	/*
1791	 * Break apart the list. We'll save the ones we want to copy
1792	 * out locally and remove them from the TCPCB list. We can
1793	 * then drop the INPCB lock while we do the copyout.
1794	 *
1795	 * There are roughly three cases:
1796	 * 1. There was nothing to copy out. That's easy: drop the
1797	 * lock and return.
1798	 * 2. We are copying out the entire list. Again, that's easy:
1799	 * move the whole list.
1800	 * 3. We are copying out a partial list. That's harder. We
1801	 * need to update the list book-keeping entries.
1802	 */
1803	if (log_entry != NULL && log_next == NULL) {
1804		/* Move entire list. */
1805		KASSERT(outnum == tp->t_lognum,
1806		    ("%s:%d: outnum (%d) should match tp->t_lognum (%d)",
1807			__func__, __LINE__, outnum, tp->t_lognum));
1808		log_tailq = tp->t_logs;
1809		tp->t_lognum = 0;
1810		STAILQ_INIT(&tp->t_logs);
1811	} else if (log_entry != NULL) {
1812		/* Move partial list. */
1813		KASSERT(outnum < tp->t_lognum,
1814		    ("%s:%d: outnum (%d) not less than tp->t_lognum (%d)",
1815			__func__, __LINE__, outnum, tp->t_lognum));
1816		STAILQ_FIRST(&log_tailq) = STAILQ_FIRST(&tp->t_logs);
1817		STAILQ_FIRST(&tp->t_logs) = STAILQ_NEXT(log_entry, tlm_queue);
1818		KASSERT(STAILQ_NEXT(log_entry, tlm_queue) != NULL,
1819		    ("%s:%d: tp->t_logs is unexpectedly shorter than expected"
1820		    "(tp: %p, log_tailq: %p, outnum: %d, tp->t_lognum: %d)",
1821		    __func__, __LINE__, tp, &log_tailq, outnum, tp->t_lognum));
1822		STAILQ_NEXT(log_entry, tlm_queue) = NULL;
1823		log_tailq.stqh_last = &STAILQ_NEXT(log_entry, tlm_queue);
1824		tp->t_lognum -= outnum;
1825	} else
1826		STAILQ_INIT(&log_tailq);
1827
1828	/* Drop the PCB lock. */
1829	INP_WUNLOCK(inp);
1830
1831	/* Copy the data out. */
1832	error = tcp_log_logs_to_buf(sopt, &log_tailq, &out_entry, outnum);
1833
1834	if (error) {
1835		/* Restore list */
1836		INP_WLOCK(inp);
1837		if ((inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) == 0) {
1838			tp = intotcpcb(inp);
1839
1840			/* Merge the two lists. */
1841			STAILQ_CONCAT(&log_tailq, &tp->t_logs);
1842			tp->t_logs = log_tailq;
1843			tp->t_lognum += outnum;
1844		}
1845		INP_WUNLOCK(inp);
1846	} else {
1847		/* Sanity check entries */
1848		KASSERT(((caddr_t)out_entry - (caddr_t)sopt->sopt_val)  ==
1849		    outsize, ("%s: Actual output size (%zu) != "
1850			"calculated output size (%zu)", __func__,
1851			(size_t)((caddr_t)out_entry - (caddr_t)sopt->sopt_val),
1852			outsize));
1853
1854		/* Free the entries we just copied out. */
1855		STAILQ_FOREACH_SAFE(log_entry, &log_tailq, tlm_queue, log_next) {
1856			tcp_log_entry_refcnt_rem(log_entry);
1857			uma_zfree(tcp_log_zone, log_entry);
1858		}
1859	}
1860
1861	sopt->sopt_valsize = (size_t)((caddr_t)out_entry -
1862	    (caddr_t)sopt->sopt_val);
1863	return (error);
1864}
1865
1866static void
1867tcp_log_free_queue(struct tcp_log_dev_queue *param)
1868{
1869	struct tcp_log_dev_log_queue *entry;
1870
1871	KASSERT(param != NULL, ("%s: called with NULL param", __func__));
1872	if (param == NULL)
1873		return;
1874
1875	entry = (struct tcp_log_dev_log_queue *)param;
1876
1877	/* Free the entries. */
1878	tcp_log_free_entries(&entry->tldl_entries, &entry->tldl_count);
1879
1880	/* Free the buffer, if it is allocated. */
1881	if (entry->tldl_common.tldq_buf != NULL)
1882		free(entry->tldl_common.tldq_buf, M_TCPLOGDEV);
1883
1884	/* Free the queue entry. */
1885	free(entry, M_TCPLOGDEV);
1886}
1887
1888static struct tcp_log_common_header *
1889tcp_log_expandlogbuf(struct tcp_log_dev_queue *param)
1890{
1891	struct tcp_log_dev_log_queue *entry;
1892	struct tcp_log_header *hdr;
1893	uint8_t *end;
1894	struct sockopt sopt;
1895	int error;
1896
1897	entry = (struct tcp_log_dev_log_queue *)param;
1898
1899	/* Take a worst-case guess at space needs. */
1900	sopt.sopt_valsize = sizeof(struct tcp_log_header) +
1901	    entry->tldl_count * (sizeof(struct tcp_log_buffer) +
1902	    sizeof(struct tcp_log_verbose));
1903	hdr = malloc(sopt.sopt_valsize, M_TCPLOGDEV, M_NOWAIT);
1904	if (hdr == NULL) {
1905#ifdef TCPLOG_DEBUG_COUNTERS
1906		counter_u64_add(tcp_log_que_fail5, entry->tldl_count);
1907#endif
1908		return (NULL);
1909	}
1910	sopt.sopt_val = hdr + 1;
1911	sopt.sopt_valsize -= sizeof(struct tcp_log_header);
1912	sopt.sopt_td = NULL;
1913
1914	error = tcp_log_logs_to_buf(&sopt, &entry->tldl_entries,
1915	    (struct tcp_log_buffer **)&end, entry->tldl_count);
1916	if (error) {
1917		free(hdr, M_TCPLOGDEV);
1918		return (NULL);
1919	}
1920
1921	/* Free the entries. */
1922	tcp_log_free_entries(&entry->tldl_entries, &entry->tldl_count);
1923	entry->tldl_count = 0;
1924
1925	memset(hdr, 0, sizeof(struct tcp_log_header));
1926	hdr->tlh_version = TCP_LOG_BUF_VER;
1927	hdr->tlh_type = TCP_LOG_DEV_TYPE_BBR;
1928	hdr->tlh_length = end - (uint8_t *)hdr;
1929	hdr->tlh_ie = entry->tldl_ie;
1930	hdr->tlh_af = entry->tldl_af;
1931	getboottime(&hdr->tlh_offset);
1932	strlcpy(hdr->tlh_id, entry->tldl_id, TCP_LOG_ID_LEN);
1933	strlcpy(hdr->tlh_reason, entry->tldl_reason, TCP_LOG_REASON_LEN);
1934	return ((struct tcp_log_common_header *)hdr);
1935}
1936
1937/*
1938 * Queue the tcpcb's log buffer for transmission via the log buffer facility.
1939 *
1940 * NOTE: This should be called with a write lock on the PCB.
1941 *
1942 * how should be M_WAITOK or M_NOWAIT. If M_WAITOK, the function will drop
1943 * and reacquire the INP lock if it needs to do so.
1944 *
1945 * If force is false, this will only dump auto-logged sessions if
1946 * tcp_log_auto_all is true or if there is a log ID defined for the session.
1947 */
1948int
1949tcp_log_dump_tp_logbuf(struct tcpcb *tp, char *reason, int how, bool force)
1950{
1951	struct tcp_log_dev_log_queue *entry;
1952	struct inpcb *inp;
1953#ifdef TCPLOG_DEBUG_COUNTERS
1954	int num_entries;
1955#endif
1956
1957	inp = tp->t_inpcb;
1958	INP_WLOCK_ASSERT(inp);
1959
1960	/* If there are no log entries, there is nothing to do. */
1961	if (tp->t_lognum == 0)
1962		return (0);
1963
1964	/* Check for a log ID. */
1965	if (tp->t_lib == NULL && (tp->t_flags2 & TF2_LOG_AUTO) &&
1966	    !tcp_log_auto_all && !force) {
1967		struct tcp_log_mem *log_entry;
1968
1969		/*
1970		 * We needed a log ID and none was found. Free the log entries
1971		 * and return success. Also, cancel further logging. If the
1972		 * session doesn't have a log ID by now, we'll assume it isn't
1973		 * going to get one.
1974		 */
1975		while ((log_entry = STAILQ_FIRST(&tp->t_logs)) != NULL)
1976			tcp_log_remove_log_head(tp, log_entry);
1977		KASSERT(tp->t_lognum == 0,
1978		    ("%s: After freeing entries, tp->t_lognum=%d (expected 0)",
1979			__func__, tp->t_lognum));
1980		tp->t_logstate = TCP_LOG_STATE_OFF;
1981		return (0);
1982	}
1983
1984	/*
1985	 * Allocate memory. If we must wait, we'll need to drop the locks
1986	 * and reacquire them (and do all the related business that goes
1987	 * along with that).
1988	 */
1989	entry = malloc(sizeof(struct tcp_log_dev_log_queue), M_TCPLOGDEV,
1990	    M_NOWAIT);
1991	if (entry == NULL && (how & M_NOWAIT)) {
1992#ifdef TCPLOG_DEBUG_COUNTERS
1993		counter_u64_add(tcp_log_que_fail3, 1);
1994#endif
1995		return (ENOBUFS);
1996	}
1997	if (entry == NULL) {
1998		INP_WUNLOCK(inp);
1999		entry = malloc(sizeof(struct tcp_log_dev_log_queue),
2000		    M_TCPLOGDEV, M_WAITOK);
2001		INP_WLOCK(inp);
2002		/*
2003		 * Note that this check is slightly overly-restrictive in
2004		 * that the TCB can survive either of these events.
2005		 * However, there is currently not a good way to ensure
2006		 * that is the case. So, if we hit this M_WAIT path, we
2007		 * may end up dropping some entries. That seems like a
2008		 * small price to pay for safety.
2009		 */
2010		if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
2011			free(entry, M_TCPLOGDEV);
2012#ifdef TCPLOG_DEBUG_COUNTERS
2013			counter_u64_add(tcp_log_que_fail2, 1);
2014#endif
2015			return (ECONNRESET);
2016		}
2017		tp = intotcpcb(inp);
2018		if (tp->t_lognum == 0) {
2019			free(entry, M_TCPLOGDEV);
2020			return (0);
2021		}
2022	}
2023
2024	/* Fill in the unique parts of the queue entry. */
2025	if (tp->t_lib != NULL)
2026		strlcpy(entry->tldl_id, tp->t_lib->tlb_id, TCP_LOG_ID_LEN);
2027	else
2028		strlcpy(entry->tldl_id, "UNKNOWN", TCP_LOG_ID_LEN);
2029	if (reason != NULL)
2030		strlcpy(entry->tldl_reason, reason, TCP_LOG_REASON_LEN);
2031	else
2032		strlcpy(entry->tldl_reason, "UNKNOWN", TCP_LOG_ID_LEN);
2033	entry->tldl_ie = inp->inp_inc.inc_ie;
2034	if (inp->inp_inc.inc_flags & INC_ISIPV6)
2035		entry->tldl_af = AF_INET6;
2036	else
2037		entry->tldl_af = AF_INET;
2038	entry->tldl_entries = tp->t_logs;
2039	entry->tldl_count = tp->t_lognum;
2040
2041	/* Fill in the common parts of the queue entry. */
2042	entry->tldl_common.tldq_buf = NULL;
2043	entry->tldl_common.tldq_xform = tcp_log_expandlogbuf;
2044	entry->tldl_common.tldq_dtor = tcp_log_free_queue;
2045
2046	/* Clear the log data from the TCPCB. */
2047#ifdef TCPLOG_DEBUG_COUNTERS
2048	num_entries = tp->t_lognum;
2049#endif
2050	tp->t_lognum = 0;
2051	STAILQ_INIT(&tp->t_logs);
2052
2053	/* Add the entry. If no one is listening, free the entry. */
2054	if (tcp_log_dev_add_log((struct tcp_log_dev_queue *)entry)) {
2055		tcp_log_free_queue((struct tcp_log_dev_queue *)entry);
2056#ifdef TCPLOG_DEBUG_COUNTERS
2057		counter_u64_add(tcp_log_que_fail1, num_entries);
2058	} else {
2059		counter_u64_add(tcp_log_queued, num_entries);
2060#endif
2061	}
2062	return (0);
2063}
2064
2065/*
2066 * Queue the log_id_node's log buffers for transmission via the log buffer
2067 * facility.
2068 *
2069 * NOTE: This should be called with the bucket locked and referenced.
2070 *
2071 * how should be M_WAITOK or M_NOWAIT. If M_WAITOK, the function will drop
2072 * and reacquire the bucket lock if it needs to do so. (The caller must
2073 * ensure that the tln is no longer on any lists so no one else will mess
2074 * with this while the lock is dropped!)
2075 */
2076static int
2077tcp_log_dump_node_logbuf(struct tcp_log_id_node *tln, char *reason, int how)
2078{
2079	struct tcp_log_dev_log_queue *entry;
2080	struct tcp_log_id_bucket *tlb;
2081
2082	tlb = tln->tln_bucket;
2083	TCPID_BUCKET_LOCK_ASSERT(tlb);
2084	KASSERT(tlb->tlb_refcnt > 0,
2085	    ("%s:%d: Called with unreferenced bucket (tln=%p, tlb=%p)",
2086	    __func__, __LINE__, tln, tlb));
2087	KASSERT(tln->tln_closed,
2088	    ("%s:%d: Called for node with tln_closed==false (tln=%p)",
2089	    __func__, __LINE__, tln));
2090
2091	/* If there are no log entries, there is nothing to do. */
2092	if (tln->tln_count == 0)
2093		return (0);
2094
2095	/*
2096	 * Allocate memory. If we must wait, we'll need to drop the locks
2097	 * and reacquire them (and do all the related business that goes
2098	 * along with that).
2099	 */
2100	entry = malloc(sizeof(struct tcp_log_dev_log_queue), M_TCPLOGDEV,
2101	    M_NOWAIT);
2102	if (entry == NULL && (how & M_NOWAIT))
2103		return (ENOBUFS);
2104	if (entry == NULL) {
2105		TCPID_BUCKET_UNLOCK(tlb);
2106		entry = malloc(sizeof(struct tcp_log_dev_log_queue),
2107		    M_TCPLOGDEV, M_WAITOK);
2108		TCPID_BUCKET_LOCK(tlb);
2109	}
2110
2111	/* Fill in the common parts of the queue entry.. */
2112	entry->tldl_common.tldq_buf = NULL;
2113	entry->tldl_common.tldq_xform = tcp_log_expandlogbuf;
2114	entry->tldl_common.tldq_dtor = tcp_log_free_queue;
2115
2116	/* Fill in the unique parts of the queue entry. */
2117	strlcpy(entry->tldl_id, tlb->tlb_id, TCP_LOG_ID_LEN);
2118	if (reason != NULL)
2119		strlcpy(entry->tldl_reason, reason, TCP_LOG_REASON_LEN);
2120	else
2121		strlcpy(entry->tldl_reason, "UNKNOWN", TCP_LOG_ID_LEN);
2122	entry->tldl_ie = tln->tln_ie;
2123	entry->tldl_entries = tln->tln_entries;
2124	entry->tldl_count = tln->tln_count;
2125	entry->tldl_af = tln->tln_af;
2126
2127	/* Add the entry. If no one is listening, free the entry. */
2128	if (tcp_log_dev_add_log((struct tcp_log_dev_queue *)entry))
2129		tcp_log_free_queue((struct tcp_log_dev_queue *)entry);
2130
2131	return (0);
2132}
2133
2134
2135/*
2136 * Queue the log buffers for all sessions in a bucket for transmissions via
2137 * the log buffer facility.
2138 *
2139 * NOTE: This should be called with a locked bucket; however, the function
2140 * will drop the lock.
2141 */
2142#define	LOCAL_SAVE	10
2143static void
2144tcp_log_dumpbucketlogs(struct tcp_log_id_bucket *tlb, char *reason)
2145{
2146	struct tcp_log_id_node local_entries[LOCAL_SAVE];
2147	struct inpcb *inp;
2148	struct tcpcb *tp;
2149	struct tcp_log_id_node *cur_tln, *prev_tln, *tmp_tln;
2150	int i, num_local_entries, tree_locked;
2151	bool expireq_locked;
2152
2153	TCPID_BUCKET_LOCK_ASSERT(tlb);
2154
2155	/*
2156	 * Take a reference on the bucket to keep it from disappearing until
2157	 * we are done.
2158	 */
2159	TCPID_BUCKET_REF(tlb);
2160
2161	/*
2162	 * We'll try to create these without dropping locks. However, we
2163	 * might very well need to drop locks to get memory. If that's the
2164	 * case, we'll save up to 10 on the stack, and sacrifice the rest.
2165	 * (Otherwise, we need to worry about finding our place again in a
2166	 * potentially changed list. It just doesn't seem worth the trouble
2167	 * to do that.
2168	 */
2169	expireq_locked = false;
2170	num_local_entries = 0;
2171	prev_tln = NULL;
2172	tree_locked = TREE_UNLOCKED;
2173	SLIST_FOREACH_SAFE(cur_tln, &tlb->tlb_head, tln_list, tmp_tln) {
2174		/*
2175		 * If this isn't associated with a TCPCB, we can pull it off
2176		 * the list now. We need to be careful that the expire timer
2177		 * hasn't already taken ownership (tln_expiretime == SBT_MAX).
2178		 * If so, we let the expire timer code free the data.
2179		 */
2180		if (cur_tln->tln_closed) {
2181no_inp:
2182			/*
2183			 * Get the expireq lock so we can get a consistent
2184			 * read of tln_expiretime and so we can remove this
2185			 * from the expireq.
2186			 */
2187			if (!expireq_locked) {
2188				TCPLOG_EXPIREQ_LOCK();
2189				expireq_locked = true;
2190			}
2191
2192			/*
2193			 * We ignore entries with tln_expiretime == SBT_MAX.
2194			 * The expire timer code already owns those.
2195			 */
2196			KASSERT(cur_tln->tln_expiretime > (sbintime_t) 0,
2197			    ("%s:%d: node on the expire queue without positive "
2198			    "expire time", __func__, __LINE__));
2199			if (cur_tln->tln_expiretime == SBT_MAX) {
2200				prev_tln = cur_tln;
2201				continue;
2202			}
2203
2204			/* Remove the entry from the expireq. */
2205			STAILQ_REMOVE(&tcp_log_expireq_head, cur_tln,
2206			    tcp_log_id_node, tln_expireq);
2207
2208			/* Remove the entry from the bucket. */
2209			if (prev_tln != NULL)
2210				SLIST_REMOVE_AFTER(prev_tln, tln_list);
2211			else
2212				SLIST_REMOVE_HEAD(&tlb->tlb_head, tln_list);
2213
2214			/*
2215			 * Drop the INP and bucket reference counts. Due to
2216			 * lock-ordering rules, we need to drop the expire
2217			 * queue lock.
2218			 */
2219			TCPLOG_EXPIREQ_UNLOCK();
2220			expireq_locked = false;
2221
2222			/* Drop the INP reference. */
2223			INP_WLOCK(cur_tln->tln_inp);
2224			if (!in_pcbrele_wlocked(cur_tln->tln_inp))
2225				INP_WUNLOCK(cur_tln->tln_inp);
2226
2227			if (tcp_log_unref_bucket(tlb, &tree_locked, NULL)) {
2228#ifdef INVARIANTS
2229				panic("%s: Bucket refcount unexpectedly 0.",
2230				    __func__);
2231#endif
2232				/*
2233				 * Recover as best we can: free the entry we
2234				 * own.
2235				 */
2236				tcp_log_free_entries(&cur_tln->tln_entries,
2237				    &cur_tln->tln_count);
2238				uma_zfree(tcp_log_node_zone, cur_tln);
2239				goto done;
2240			}
2241
2242			if (tcp_log_dump_node_logbuf(cur_tln, reason,
2243			    M_NOWAIT)) {
2244				/*
2245				 * If we have sapce, save the entries locally.
2246				 * Otherwise, free them.
2247				 */
2248				if (num_local_entries < LOCAL_SAVE) {
2249					local_entries[num_local_entries] =
2250					    *cur_tln;
2251					num_local_entries++;
2252				} else {
2253					tcp_log_free_entries(
2254					    &cur_tln->tln_entries,
2255					    &cur_tln->tln_count);
2256				}
2257			}
2258
2259			/* No matter what, we are done with the node now. */
2260			uma_zfree(tcp_log_node_zone, cur_tln);
2261
2262			/*
2263			 * Because we removed this entry from the list, prev_tln
2264			 * (which tracks the previous entry still on the tlb
2265			 * list) remains unchanged.
2266			 */
2267			continue;
2268		}
2269
2270		/*
2271		 * If we get to this point, the session data is still held in
2272		 * the TCPCB. So, we need to pull the data out of that.
2273		 *
2274		 * We will need to drop the expireq lock so we can lock the INP.
2275		 * We can then try to extract the data the "easy" way. If that
2276		 * fails, we'll save the log entries for later.
2277		 */
2278		if (expireq_locked) {
2279			TCPLOG_EXPIREQ_UNLOCK();
2280			expireq_locked = false;
2281		}
2282
2283		/* Lock the INP and then re-check the state. */
2284		inp = cur_tln->tln_inp;
2285		INP_WLOCK(inp);
2286		/*
2287		 * If we caught this while it was transitioning, the data
2288		 * might have moved from the TCPCB to the tln (signified by
2289		 * setting tln_closed to true. If so, treat this like an
2290		 * inactive connection.
2291		 */
2292		if (cur_tln->tln_closed) {
2293			/*
2294			 * It looks like we may have caught this connection
2295			 * while it was transitioning from active to inactive.
2296			 * Treat this like an inactive connection.
2297			 */
2298			INP_WUNLOCK(inp);
2299			goto no_inp;
2300		}
2301
2302		/*
2303		 * Try to dump the data from the tp without dropping the lock.
2304		 * If this fails, try to save off the data locally.
2305		 */
2306		tp = cur_tln->tln_tp;
2307		if (tcp_log_dump_tp_logbuf(tp, reason, M_NOWAIT, true) &&
2308		    num_local_entries < LOCAL_SAVE) {
2309			tcp_log_move_tp_to_node(tp,
2310			    &local_entries[num_local_entries]);
2311			local_entries[num_local_entries].tln_closed = 1;
2312			KASSERT(local_entries[num_local_entries].tln_bucket ==
2313			    tlb, ("%s: %d: bucket mismatch for node %p",
2314			    __func__, __LINE__, cur_tln));
2315			num_local_entries++;
2316		}
2317
2318		INP_WUNLOCK(inp);
2319
2320		/*
2321		 * We are goint to leave the current tln on the list. It will
2322		 * become the previous tln.
2323		 */
2324		prev_tln = cur_tln;
2325	}
2326
2327	/* Drop our locks, if any. */
2328	KASSERT(tree_locked == TREE_UNLOCKED,
2329	    ("%s: %d: tree unexpectedly locked", __func__, __LINE__));
2330	switch (tree_locked) {
2331	case TREE_WLOCKED:
2332		TCPID_TREE_WUNLOCK();
2333		tree_locked = TREE_UNLOCKED;
2334		break;
2335	case TREE_RLOCKED:
2336		TCPID_TREE_RUNLOCK();
2337		tree_locked = TREE_UNLOCKED;
2338		break;
2339	}
2340	if (expireq_locked) {
2341		TCPLOG_EXPIREQ_UNLOCK();
2342		expireq_locked = false;
2343	}
2344
2345	/*
2346	 * Try again for any saved entries. tcp_log_dump_node_logbuf() is
2347	 * guaranteed to free the log entries within the node. And, since
2348	 * the node itself is on our stack, we don't need to free it.
2349	 */
2350	for (i = 0; i < num_local_entries; i++)
2351		tcp_log_dump_node_logbuf(&local_entries[i], reason, M_WAITOK);
2352
2353	/* Drop our reference. */
2354	if (!tcp_log_unref_bucket(tlb, &tree_locked, NULL))
2355		TCPID_BUCKET_UNLOCK(tlb);
2356
2357done:
2358	/* Drop our locks, if any. */
2359	switch (tree_locked) {
2360	case TREE_WLOCKED:
2361		TCPID_TREE_WUNLOCK();
2362		break;
2363	case TREE_RLOCKED:
2364		TCPID_TREE_RUNLOCK();
2365		break;
2366	}
2367	if (expireq_locked)
2368		TCPLOG_EXPIREQ_UNLOCK();
2369}
2370#undef	LOCAL_SAVE
2371
2372
2373/*
2374 * Queue the log buffers for all sessions in a bucket for transmissions via
2375 * the log buffer facility.
2376 *
2377 * NOTE: This should be called with a locked INP; however, the function
2378 * will drop the lock.
2379 */
2380void
2381tcp_log_dump_tp_bucket_logbufs(struct tcpcb *tp, char *reason)
2382{
2383	struct tcp_log_id_bucket *tlb;
2384	int tree_locked;
2385
2386	/* Figure out our bucket and lock it. */
2387	INP_WLOCK_ASSERT(tp->t_inpcb);
2388	tlb = tp->t_lib;
2389	if (tlb == NULL) {
2390		/*
2391		 * No bucket; treat this like a request to dump a single
2392		 * session's traces.
2393		 */
2394		(void)tcp_log_dump_tp_logbuf(tp, reason, M_WAITOK, true);
2395		INP_WUNLOCK(tp->t_inpcb);
2396		return;
2397	}
2398	TCPID_BUCKET_REF(tlb);
2399	INP_WUNLOCK(tp->t_inpcb);
2400	TCPID_BUCKET_LOCK(tlb);
2401
2402	/* If we are the last reference, we have nothing more to do here. */
2403	tree_locked = TREE_UNLOCKED;
2404	if (tcp_log_unref_bucket(tlb, &tree_locked, NULL)) {
2405		switch (tree_locked) {
2406		case TREE_WLOCKED:
2407			TCPID_TREE_WUNLOCK();
2408			break;
2409		case TREE_RLOCKED:
2410			TCPID_TREE_RUNLOCK();
2411			break;
2412		}
2413		return;
2414	}
2415
2416	/* Turn this over to tcp_log_dumpbucketlogs() to finish the work. */
2417	tcp_log_dumpbucketlogs(tlb, reason);
2418}
2419
2420/*
2421 * Mark the end of a flow with the current stack. A stack can add
2422 * stack-specific info to this trace event by overriding this
2423 * function (see bbr_log_flowend() for example).
2424 */
2425void
2426tcp_log_flowend(struct tcpcb *tp)
2427{
2428	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
2429		struct socket *so = tp->t_inpcb->inp_socket;
2430		TCP_LOG_EVENT(tp, NULL, &so->so_rcv, &so->so_snd,
2431				TCP_LOG_FLOWEND, 0, 0, NULL, false);
2432	}
2433}
2434
2435