xref: /freebsd/sys/dev/cxgbe/t4_l2t.c (revision 3cbb4cc200f8a0ad7ed08233425ea54524a21f1c)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2012 Chelsio Communications, Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include "opt_inet.h"
32 #include "opt_inet6.h"
33 
34 #include <sys/param.h>
35 #include <sys/eventhandler.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/module.h>
39 #include <sys/bus.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/rwlock.h>
43 #include <sys/socket.h>
44 #include <sys/sbuf.h>
45 #include <netinet/in.h>
46 
47 #include "common/common.h"
48 #include "common/t4_msg.h"
49 #include "t4_l2t.h"
50 
51 /*
52  * Module locking notes:  There is a RW lock protecting the L2 table as a
53  * whole plus a spinlock per L2T entry.  Entry lookups and allocations happen
54  * under the protection of the table lock, individual entry changes happen
55  * while holding that entry's spinlock.  The table lock nests outside the
56  * entry locks.  Allocations of new entries take the table lock as writers so
57  * no other lookups can happen while allocating new entries.  Entry updates
58  * take the table lock as readers so multiple entries can be updated in
59  * parallel.  An L2T entry can be dropped by decrementing its reference count
60  * and therefore can happen in parallel with entry allocation but no entry
61  * can change state or increment its ref count during allocation as both of
62  * these perform lookups.
63  *
64  * Note: We do not take references to ifnets in this module because both
65  * the TOE and the sockets already hold references to the interfaces and the
66  * lifetime of an L2T entry is fully contained in the lifetime of the TOE.
67  */
68 
69 /*
70  * Allocate a free L2T entry.  Must be called with l2t_data.lock held.
71  */
72 struct l2t_entry *
73 t4_alloc_l2e(struct l2t_data *d)
74 {
75 	struct l2t_entry *end, *e, **p;
76 
77 	rw_assert(&d->lock, RA_WLOCKED);
78 
79 	if (!atomic_load_acq_int(&d->nfree))
80 		return (NULL);
81 
82 	/* there's definitely a free entry */
83 	for (e = d->rover, end = &d->l2tab[d->l2t_size]; e != end; ++e)
84 		if (atomic_load_acq_int(&e->refcnt) == 0)
85 			goto found;
86 
87 	for (e = d->l2tab; atomic_load_acq_int(&e->refcnt); ++e)
88 		continue;
89 found:
90 	d->rover = e + 1;
91 	atomic_subtract_int(&d->nfree, 1);
92 
93 	/*
94 	 * The entry we found may be an inactive entry that is
95 	 * presently in the hash table.  We need to remove it.
96 	 */
97 	if (e->state < L2T_STATE_SWITCHING) {
98 		for (p = &d->l2tab[e->hash].first; *p; p = &(*p)->next) {
99 			if (*p == e) {
100 				*p = e->next;
101 				e->next = NULL;
102 				break;
103 			}
104 		}
105 	}
106 
107 	e->state = L2T_STATE_UNUSED;
108 	return (e);
109 }
110 
111 static struct l2t_entry *
112 find_or_alloc_l2e(struct l2t_data *d, uint16_t vlan, uint8_t port, uint8_t *dmac)
113 {
114 	struct l2t_entry *end, *e, **p;
115 	struct l2t_entry *first_free = NULL;
116 
117 	for (e = &d->l2tab[0], end = &d->l2tab[d->l2t_size]; e != end; ++e) {
118 		if (atomic_load_acq_int(&e->refcnt) == 0) {
119 			if (!first_free)
120 				first_free = e;
121 		} else if (e->state == L2T_STATE_SWITCHING &&
122 		    memcmp(e->dmac, dmac, ETHER_ADDR_LEN) == 0 &&
123 		    e->vlan == vlan && e->lport == port)
124 			return (e);	/* Found existing entry that matches. */
125 	}
126 
127 	if (first_free == NULL)
128 		return (NULL);	/* No match and no room for a new entry. */
129 
130 	/*
131 	 * The entry we found may be an inactive entry that is
132 	 * presently in the hash table.  We need to remove it.
133 	 */
134 	e = first_free;
135 	if (e->state < L2T_STATE_SWITCHING) {
136 		for (p = &d->l2tab[e->hash].first; *p; p = &(*p)->next) {
137 			if (*p == e) {
138 				*p = e->next;
139 				e->next = NULL;
140 				break;
141 			}
142 		}
143 	}
144 	e->state = L2T_STATE_UNUSED;
145 	return (e);
146 }
147 
148 static void
149 mk_write_l2e(struct adapter *sc, struct l2t_entry *e, int sync, int reply,
150     void *dst)
151 {
152 	struct cpl_l2t_write_req *req;
153 	int idx;
154 
155 	req = dst;
156 	idx = e->idx + sc->vres.l2t.start;
157 	INIT_TP_WR(req, 0);
158 	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_L2T_WRITE_REQ, idx |
159 	    V_SYNC_WR(sync) | V_TID_QID(e->iqid)));
160 	req->params = htons(V_L2T_W_PORT(e->lport) | V_L2T_W_NOREPLY(!reply));
161 	req->l2t_idx = htons(idx);
162 	req->vlan = htons(e->vlan);
163 	memcpy(req->dst_mac, e->dmac, sizeof(req->dst_mac));
164 }
165 
166 /*
167  * Write an L2T entry.  Must be called with the entry locked.
168  * The write may be synchronous or asynchronous.
169  */
170 int
171 t4_write_l2e(struct l2t_entry *e, int sync)
172 {
173 	struct sge_wrq *wrq;
174 	struct adapter *sc;
175 	struct wrq_cookie cookie;
176 	struct cpl_l2t_write_req *req;
177 
178 	mtx_assert(&e->lock, MA_OWNED);
179 	MPASS(e->wrq != NULL);
180 
181 	wrq = e->wrq;
182 	sc = wrq->adapter;
183 
184 	req = start_wrq_wr(wrq, howmany(sizeof(*req), 16), &cookie);
185 	if (req == NULL)
186 		return (ENOMEM);
187 
188 	mk_write_l2e(sc, e, sync, sync, req);
189 
190 	commit_wrq_wr(wrq, req, &cookie);
191 
192 	if (sync && e->state != L2T_STATE_SWITCHING)
193 		e->state = L2T_STATE_SYNC_WRITE;
194 
195 	return (0);
196 }
197 
198 /*
199  * Allocate an L2T entry for use by a TLS connection.  These entries are
200  * associated with a specific VLAN and destination MAC that never changes.
201  * However, multiple TLS connections might share a single entry.
202  *
203  * If a new L2T entry is allocated, a work request to initialize it is
204  * written to 'txq' and 'ndesc' will be set to 1.  Otherwise, 'ndesc'
205  * will be set to 0.
206  *
207  * To avoid races, separate L2T entries are reserved for individual
208  * queues since the L2T entry update is written to a txq just prior to
209  * TLS work requests that will depend on it being written.
210  */
211 struct l2t_entry *
212 t4_l2t_alloc_tls(struct adapter *sc, struct sge_txq *txq, void *dst,
213     int *ndesc, uint16_t vlan, uint8_t port, uint8_t *eth_addr)
214 {
215 	struct l2t_data *d;
216 	struct l2t_entry *e;
217 	int i;
218 
219 	TXQ_LOCK_ASSERT_OWNED(txq);
220 
221 	d = sc->l2t;
222 	*ndesc = 0;
223 
224 	rw_rlock(&d->lock);
225 
226 	/* First, try to find an existing entry. */
227 	for (i = 0; i < d->l2t_size; i++) {
228 		e = &d->l2tab[i];
229 		if (e->state != L2T_STATE_TLS)
230 			continue;
231 		if (e->vlan == vlan && e->lport == port &&
232 		    e->wrq == (struct sge_wrq *)txq &&
233 		    memcmp(e->dmac, eth_addr, ETHER_ADDR_LEN) == 0) {
234 			if (atomic_fetchadd_int(&e->refcnt, 1) == 0) {
235 				/*
236 				 * This entry wasn't held but is still
237 				 * valid, so decrement nfree.
238 				 */
239 				atomic_subtract_int(&d->nfree, 1);
240 			}
241 			KASSERT(e->refcnt > 0,
242 			    ("%s: refcount overflow", __func__));
243 			rw_runlock(&d->lock);
244 			return (e);
245 		}
246 	}
247 
248 	/*
249 	 * Don't bother rechecking if the upgrade fails since the txq is
250 	 * already locked.
251 	 */
252 	if (!rw_try_upgrade(&d->lock)) {
253 		rw_runlock(&d->lock);
254 		rw_wlock(&d->lock);
255 	}
256 
257 	/* Match not found, allocate a new entry. */
258 	e = t4_alloc_l2e(d);
259 	if (e == NULL) {
260 		rw_wunlock(&d->lock);
261 		return (e);
262 	}
263 
264 	/* Initialize the entry. */
265 	e->state = L2T_STATE_TLS;
266 	e->vlan = vlan;
267 	e->lport = port;
268 	e->iqid = sc->sge.fwq.abs_id;
269 	e->wrq = (struct sge_wrq *)txq;
270 	memcpy(e->dmac, eth_addr, ETHER_ADDR_LEN);
271 	atomic_store_rel_int(&e->refcnt, 1);
272 	rw_wunlock(&d->lock);
273 
274 	/* Write out the work request. */
275 	*ndesc = howmany(sizeof(struct cpl_l2t_write_req), EQ_ESIZE);
276 	MPASS(*ndesc == 1);
277 	mk_write_l2e(sc, e, 1, 0, dst);
278 
279 	return (e);
280 }
281 
282 /*
283  * Allocate an L2T entry for use by a switching rule.  Such need to be
284  * explicitly freed and while busy they are not on any hash chain, so normal
285  * address resolution updates do not see them.
286  */
287 struct l2t_entry *
288 t4_l2t_alloc_switching(struct adapter *sc, uint16_t vlan, uint8_t port,
289     uint8_t *eth_addr)
290 {
291 	struct l2t_data *d = sc->l2t;
292 	struct l2t_entry *e;
293 	int rc;
294 
295 	rw_wlock(&d->lock);
296 	e = find_or_alloc_l2e(d, vlan, port, eth_addr);
297 	if (e) {
298 		if (atomic_load_acq_int(&e->refcnt) == 0) {
299 			mtx_lock(&e->lock);    /* avoid race with t4_l2t_free */
300 			e->wrq = &sc->sge.ctrlq[0];
301 			e->iqid = sc->sge.fwq.abs_id;
302 			e->state = L2T_STATE_SWITCHING;
303 			e->vlan = vlan;
304 			e->lport = port;
305 			memcpy(e->dmac, eth_addr, ETHER_ADDR_LEN);
306 			atomic_store_rel_int(&e->refcnt, 1);
307 			atomic_subtract_int(&d->nfree, 1);
308 			rc = t4_write_l2e(e, 0);
309 			mtx_unlock(&e->lock);
310 			if (rc != 0)
311 				e = NULL;
312 		} else {
313 			MPASS(e->vlan == vlan);
314 			MPASS(e->lport == port);
315 			atomic_add_int(&e->refcnt, 1);
316 		}
317 	}
318 	rw_wunlock(&d->lock);
319 	return (e);
320 }
321 
322 int
323 t4_init_l2t(struct adapter *sc, int flags)
324 {
325 	int i, l2t_size;
326 	struct l2t_data *d;
327 
328 	l2t_size = sc->vres.l2t.size;
329 	if (l2t_size < 2)	/* At least 1 bucket for IP and 1 for IPv6 */
330 		return (EINVAL);
331 
332 	d = malloc(sizeof(*d) + l2t_size * sizeof (struct l2t_entry), M_CXGBE,
333 	    M_ZERO | flags);
334 	if (!d)
335 		return (ENOMEM);
336 
337 	d->l2t_size = l2t_size;
338 	d->rover = d->l2tab;
339 	atomic_store_rel_int(&d->nfree, l2t_size);
340 	rw_init(&d->lock, "L2T");
341 
342 	for (i = 0; i < l2t_size; i++) {
343 		struct l2t_entry *e = &d->l2tab[i];
344 
345 		e->idx = i;
346 		e->state = L2T_STATE_UNUSED;
347 		mtx_init(&e->lock, "L2T_E", NULL, MTX_DEF);
348 		STAILQ_INIT(&e->wr_list);
349 		atomic_store_rel_int(&e->refcnt, 0);
350 	}
351 
352 	sc->l2t = d;
353 
354 	return (0);
355 }
356 
357 int
358 t4_free_l2t(struct l2t_data *d)
359 {
360 	int i;
361 
362 	for (i = 0; i < d->l2t_size; i++)
363 		mtx_destroy(&d->l2tab[i].lock);
364 	rw_destroy(&d->lock);
365 	free(d, M_CXGBE);
366 
367 	return (0);
368 }
369 
370 int
371 do_l2t_write_rpl(struct sge_iq *iq, const struct rss_header *rss,
372     struct mbuf *m)
373 {
374 	const struct cpl_l2t_write_rpl *rpl = (const void *)(rss + 1);
375 	unsigned int tid = GET_TID(rpl);
376 	unsigned int idx = tid % L2T_SIZE;
377 
378 	if (__predict_false(rpl->status != CPL_ERR_NONE)) {
379 		log(LOG_ERR,
380 		    "Unexpected L2T_WRITE_RPL (%u) for entry at hw_idx %u\n",
381 		    rpl->status, idx);
382 		return (EINVAL);
383 	}
384 
385 	return (0);
386 }
387 
388 static inline unsigned int
389 vlan_prio(const struct l2t_entry *e)
390 {
391 	return e->vlan >> 13;
392 }
393 
394 static char
395 l2e_state(const struct l2t_entry *e)
396 {
397 	switch (e->state) {
398 	case L2T_STATE_VALID: return 'V';  /* valid, fast-path entry */
399 	case L2T_STATE_STALE: return 'S';  /* needs revalidation, but usable */
400 	case L2T_STATE_SYNC_WRITE: return 'W';
401 	case L2T_STATE_RESOLVING: return STAILQ_EMPTY(&e->wr_list) ? 'R' : 'A';
402 	case L2T_STATE_SWITCHING: return 'X';
403 	case L2T_STATE_TLS: return 'T';
404 	default: return 'U';
405 	}
406 }
407 
408 int
409 sysctl_l2t(SYSCTL_HANDLER_ARGS)
410 {
411 	struct adapter *sc = arg1;
412 	struct l2t_data *l2t = sc->l2t;
413 	struct l2t_entry *e;
414 	struct sbuf *sb;
415 	int rc, i, header = 0;
416 	char ip[INET6_ADDRSTRLEN];
417 
418 	if (l2t == NULL)
419 		return (ENXIO);
420 
421 	rc = sysctl_wire_old_buffer(req, 0);
422 	if (rc != 0)
423 		return (rc);
424 
425 	sb = sbuf_new_for_sysctl(NULL, NULL, 4096, req);
426 	if (sb == NULL)
427 		return (ENOMEM);
428 
429 	e = &l2t->l2tab[0];
430 	for (i = 0; i < l2t->l2t_size; i++, e++) {
431 		mtx_lock(&e->lock);
432 		if (e->state == L2T_STATE_UNUSED)
433 			goto skip;
434 
435 		if (header == 0) {
436 			sbuf_printf(sb, " Idx IP address      "
437 			    "Ethernet address  VLAN/P LP State Users Port");
438 			header = 1;
439 		}
440 		if (e->state >= L2T_STATE_SWITCHING)
441 			ip[0] = 0;
442 		else {
443 			inet_ntop(e->ipv6 ? AF_INET6 : AF_INET, &e->addr[0],
444 			    &ip[0], sizeof(ip));
445 		}
446 
447 		/*
448 		 * XXX: IPv6 addresses may not align properly in the output.
449 		 */
450 		sbuf_printf(sb, "\n%4u %-15s %02x:%02x:%02x:%02x:%02x:%02x %4d"
451 			   " %u %2u   %c   %5u %s",
452 			   e->idx, ip, e->dmac[0], e->dmac[1], e->dmac[2],
453 			   e->dmac[3], e->dmac[4], e->dmac[5],
454 			   e->vlan & 0xfff, vlan_prio(e), e->lport,
455 			   l2e_state(e), atomic_load_acq_int(&e->refcnt),
456 			   e->ifp ? e->ifp->if_xname : "-");
457 skip:
458 		mtx_unlock(&e->lock);
459 	}
460 
461 	rc = sbuf_finish(sb);
462 	sbuf_delete(sb);
463 
464 	return (rc);
465 }
466