1 /*
2  * This file is part of the Chelsio T4 Ethernet driver for Linux.
3  *
4  * Copyright (c) 2003-2010 Chelsio Communications, Inc. All rights reserved.
5  *
6  * This software is available to you under a choice of one of two
7  * licenses.  You may choose to be licensed under the terms of the GNU
8  * General Public License (GPL) Version 2, available from the file
9  * COPYING in the main directory of this source tree, or the
10  * OpenIB.org BSD license below:
11  *
12  *     Redistribution and use in source and binary forms, with or
13  *     without modification, are permitted provided that the following
14  *     conditions are met:
15  *
16  *      - Redistributions of source code must retain the above
17  *        copyright notice, this list of conditions and the following
18  *        disclaimer.
19  *
20  *      - Redistributions in binary form must reproduce the above
21  *        copyright notice, this list of conditions and the following
22  *        disclaimer in the documentation and/or other materials
23  *        provided with the distribution.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
29  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
30  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
31  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32  * SOFTWARE.
33  */
34 
35 #include <linux/skbuff.h>
36 #include <linux/netdevice.h>
37 #include <linux/if.h>
38 #include <linux/if_vlan.h>
39 #include <linux/jhash.h>
40 #include <linux/module.h>
41 #include <linux/debugfs.h>
42 #include <linux/seq_file.h>
43 #include <net/neighbour.h>
44 #include "cxgb4.h"
45 #include "l2t.h"
46 #include "t4_msg.h"
47 #include "t4fw_api.h"
48 
49 #define VLAN_NONE 0xfff
50 
51 /* identifies sync vs async L2T_WRITE_REQs */
52 #define F_SYNC_WR    (1 << 12)
53 
54 enum {
55 	L2T_STATE_VALID,      /* entry is up to date */
56 	L2T_STATE_STALE,      /* entry may be used but needs revalidation */
57 	L2T_STATE_RESOLVING,  /* entry needs address resolution */
58 	L2T_STATE_SYNC_WRITE, /* synchronous write of entry underway */
59 
60 	/* when state is one of the below the entry is not hashed */
61 	L2T_STATE_SWITCHING,  /* entry is being used by a switching filter */
62 	L2T_STATE_UNUSED      /* entry not in use */
63 };
64 
65 struct l2t_data {
66 	rwlock_t lock;
67 	atomic_t nfree;             /* number of free entries */
68 	struct l2t_entry *rover;    /* starting point for next allocation */
69 	struct l2t_entry l2tab[L2T_SIZE];
70 };
71 
72 static inline unsigned int vlan_prio(const struct l2t_entry *e)
73 {
74 	return e->vlan >> 13;
75 }
76 
77 static inline void l2t_hold(struct l2t_data *d, struct l2t_entry *e)
78 {
79 	if (atomic_add_return(1, &e->refcnt) == 1)  /* 0 -> 1 transition */
80 		atomic_dec(&d->nfree);
81 }
82 
83 /*
84  * To avoid having to check address families we do not allow v4 and v6
85  * neighbors to be on the same hash chain.  We keep v4 entries in the first
86  * half of available hash buckets and v6 in the second.
87  */
88 enum {
89 	L2T_SZ_HALF = L2T_SIZE / 2,
90 	L2T_HASH_MASK = L2T_SZ_HALF - 1
91 };
92 
93 static inline unsigned int arp_hash(const u32 *key, int ifindex)
94 {
95 	return jhash_2words(*key, ifindex, 0) & L2T_HASH_MASK;
96 }
97 
98 static inline unsigned int ipv6_hash(const u32 *key, int ifindex)
99 {
100 	u32 xor = key[0] ^ key[1] ^ key[2] ^ key[3];
101 
102 	return L2T_SZ_HALF + (jhash_2words(xor, ifindex, 0) & L2T_HASH_MASK);
103 }
104 
105 static unsigned int addr_hash(const u32 *addr, int addr_len, int ifindex)
106 {
107 	return addr_len == 4 ? arp_hash(addr, ifindex) :
108 			       ipv6_hash(addr, ifindex);
109 }
110 
111 /*
112  * Checks if an L2T entry is for the given IP/IPv6 address.  It does not check
113  * whether the L2T entry and the address are of the same address family.
114  * Callers ensure an address is only checked against L2T entries of the same
115  * family, something made trivial by the separation of IP and IPv6 hash chains
116  * mentioned above.  Returns 0 if there's a match,
117  */
118 static int addreq(const struct l2t_entry *e, const u32 *addr)
119 {
120 	if (e->v6)
121 		return (e->addr[0] ^ addr[0]) | (e->addr[1] ^ addr[1]) |
122 		       (e->addr[2] ^ addr[2]) | (e->addr[3] ^ addr[3]);
123 	return e->addr[0] ^ addr[0];
124 }
125 
126 static void neigh_replace(struct l2t_entry *e, struct neighbour *n)
127 {
128 	neigh_hold(n);
129 	if (e->neigh)
130 		neigh_release(e->neigh);
131 	e->neigh = n;
132 }
133 
134 /*
135  * Write an L2T entry.  Must be called with the entry locked.
136  * The write may be synchronous or asynchronous.
137  */
138 static int write_l2e(struct adapter *adap, struct l2t_entry *e, int sync)
139 {
140 	struct sk_buff *skb;
141 	struct cpl_l2t_write_req *req;
142 
143 	skb = alloc_skb(sizeof(*req), GFP_ATOMIC);
144 	if (!skb)
145 		return -ENOMEM;
146 
147 	req = (struct cpl_l2t_write_req *)__skb_put(skb, sizeof(*req));
148 	INIT_TP_WR(req, 0);
149 
150 	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_L2T_WRITE_REQ,
151 					e->idx | (sync ? F_SYNC_WR : 0) |
152 					TID_QID(adap->sge.fw_evtq.abs_id)));
153 	req->params = htons(L2T_W_PORT(e->lport) | L2T_W_NOREPLY(!sync));
154 	req->l2t_idx = htons(e->idx);
155 	req->vlan = htons(e->vlan);
156 	if (e->neigh)
157 		memcpy(e->dmac, e->neigh->ha, sizeof(e->dmac));
158 	memcpy(req->dst_mac, e->dmac, sizeof(req->dst_mac));
159 
160 	set_wr_txq(skb, CPL_PRIORITY_CONTROL, 0);
161 	t4_ofld_send(adap, skb);
162 
163 	if (sync && e->state != L2T_STATE_SWITCHING)
164 		e->state = L2T_STATE_SYNC_WRITE;
165 	return 0;
166 }
167 
168 /*
169  * Send packets waiting in an L2T entry's ARP queue.  Must be called with the
170  * entry locked.
171  */
172 static void send_pending(struct adapter *adap, struct l2t_entry *e)
173 {
174 	while (e->arpq_head) {
175 		struct sk_buff *skb = e->arpq_head;
176 
177 		e->arpq_head = skb->next;
178 		skb->next = NULL;
179 		t4_ofld_send(adap, skb);
180 	}
181 	e->arpq_tail = NULL;
182 }
183 
184 /*
185  * Process a CPL_L2T_WRITE_RPL.  Wake up the ARP queue if it completes a
186  * synchronous L2T_WRITE.  Note that the TID in the reply is really the L2T
187  * index it refers to.
188  */
189 void do_l2t_write_rpl(struct adapter *adap, const struct cpl_l2t_write_rpl *rpl)
190 {
191 	unsigned int tid = GET_TID(rpl);
192 	unsigned int idx = tid & (L2T_SIZE - 1);
193 
194 	if (unlikely(rpl->status != CPL_ERR_NONE)) {
195 		dev_err(adap->pdev_dev,
196 			"Unexpected L2T_WRITE_RPL status %u for entry %u\n",
197 			rpl->status, idx);
198 		return;
199 	}
200 
201 	if (tid & F_SYNC_WR) {
202 		struct l2t_entry *e = &adap->l2t->l2tab[idx];
203 
204 		spin_lock(&e->lock);
205 		if (e->state != L2T_STATE_SWITCHING) {
206 			send_pending(adap, e);
207 			e->state = (e->neigh->nud_state & NUD_STALE) ?
208 					L2T_STATE_STALE : L2T_STATE_VALID;
209 		}
210 		spin_unlock(&e->lock);
211 	}
212 }
213 
214 /*
215  * Add a packet to an L2T entry's queue of packets awaiting resolution.
216  * Must be called with the entry's lock held.
217  */
218 static inline void arpq_enqueue(struct l2t_entry *e, struct sk_buff *skb)
219 {
220 	skb->next = NULL;
221 	if (e->arpq_head)
222 		e->arpq_tail->next = skb;
223 	else
224 		e->arpq_head = skb;
225 	e->arpq_tail = skb;
226 }
227 
228 int cxgb4_l2t_send(struct net_device *dev, struct sk_buff *skb,
229 		   struct l2t_entry *e)
230 {
231 	struct adapter *adap = netdev2adap(dev);
232 
233 again:
234 	switch (e->state) {
235 	case L2T_STATE_STALE:     /* entry is stale, kick off revalidation */
236 		neigh_event_send(e->neigh, NULL);
237 		spin_lock_bh(&e->lock);
238 		if (e->state == L2T_STATE_STALE)
239 			e->state = L2T_STATE_VALID;
240 		spin_unlock_bh(&e->lock);
241 	case L2T_STATE_VALID:     /* fast-path, send the packet on */
242 		return t4_ofld_send(adap, skb);
243 	case L2T_STATE_RESOLVING:
244 	case L2T_STATE_SYNC_WRITE:
245 		spin_lock_bh(&e->lock);
246 		if (e->state != L2T_STATE_SYNC_WRITE &&
247 		    e->state != L2T_STATE_RESOLVING) {
248 			spin_unlock_bh(&e->lock);
249 			goto again;
250 		}
251 		arpq_enqueue(e, skb);
252 		spin_unlock_bh(&e->lock);
253 
254 		if (e->state == L2T_STATE_RESOLVING &&
255 		    !neigh_event_send(e->neigh, NULL)) {
256 			spin_lock_bh(&e->lock);
257 			if (e->state == L2T_STATE_RESOLVING && e->arpq_head)
258 				write_l2e(adap, e, 1);
259 			spin_unlock_bh(&e->lock);
260 		}
261 	}
262 	return 0;
263 }
264 EXPORT_SYMBOL(cxgb4_l2t_send);
265 
266 /*
267  * Allocate a free L2T entry.  Must be called with l2t_data.lock held.
268  */
269 static struct l2t_entry *alloc_l2e(struct l2t_data *d)
270 {
271 	struct l2t_entry *end, *e, **p;
272 
273 	if (!atomic_read(&d->nfree))
274 		return NULL;
275 
276 	/* there's definitely a free entry */
277 	for (e = d->rover, end = &d->l2tab[L2T_SIZE]; e != end; ++e)
278 		if (atomic_read(&e->refcnt) == 0)
279 			goto found;
280 
281 	for (e = d->l2tab; atomic_read(&e->refcnt); ++e)
282 		;
283 found:
284 	d->rover = e + 1;
285 	atomic_dec(&d->nfree);
286 
287 	/*
288 	 * The entry we found may be an inactive entry that is
289 	 * presently in the hash table.  We need to remove it.
290 	 */
291 	if (e->state < L2T_STATE_SWITCHING)
292 		for (p = &d->l2tab[e->hash].first; *p; p = &(*p)->next)
293 			if (*p == e) {
294 				*p = e->next;
295 				e->next = NULL;
296 				break;
297 			}
298 
299 	e->state = L2T_STATE_UNUSED;
300 	return e;
301 }
302 
303 /*
304  * Called when an L2T entry has no more users.
305  */
306 static void t4_l2e_free(struct l2t_entry *e)
307 {
308 	struct l2t_data *d;
309 
310 	spin_lock_bh(&e->lock);
311 	if (atomic_read(&e->refcnt) == 0) {  /* hasn't been recycled */
312 		if (e->neigh) {
313 			neigh_release(e->neigh);
314 			e->neigh = NULL;
315 		}
316 		while (e->arpq_head) {
317 			struct sk_buff *skb = e->arpq_head;
318 
319 			e->arpq_head = skb->next;
320 			kfree_skb(skb);
321 		}
322 		e->arpq_tail = NULL;
323 	}
324 	spin_unlock_bh(&e->lock);
325 
326 	d = container_of(e, struct l2t_data, l2tab[e->idx]);
327 	atomic_inc(&d->nfree);
328 }
329 
330 void cxgb4_l2t_release(struct l2t_entry *e)
331 {
332 	if (atomic_dec_and_test(&e->refcnt))
333 		t4_l2e_free(e);
334 }
335 EXPORT_SYMBOL(cxgb4_l2t_release);
336 
337 /*
338  * Update an L2T entry that was previously used for the same next hop as neigh.
339  * Must be called with softirqs disabled.
340  */
341 static void reuse_entry(struct l2t_entry *e, struct neighbour *neigh)
342 {
343 	unsigned int nud_state;
344 
345 	spin_lock(&e->lock);                /* avoid race with t4_l2t_free */
346 	if (neigh != e->neigh)
347 		neigh_replace(e, neigh);
348 	nud_state = neigh->nud_state;
349 	if (memcmp(e->dmac, neigh->ha, sizeof(e->dmac)) ||
350 	    !(nud_state & NUD_VALID))
351 		e->state = L2T_STATE_RESOLVING;
352 	else if (nud_state & NUD_CONNECTED)
353 		e->state = L2T_STATE_VALID;
354 	else
355 		e->state = L2T_STATE_STALE;
356 	spin_unlock(&e->lock);
357 }
358 
359 struct l2t_entry *cxgb4_l2t_get(struct l2t_data *d, struct neighbour *neigh,
360 				const struct net_device *physdev,
361 				unsigned int priority)
362 {
363 	u8 lport;
364 	u16 vlan;
365 	struct l2t_entry *e;
366 	int addr_len = neigh->tbl->key_len;
367 	u32 *addr = (u32 *)neigh->primary_key;
368 	int ifidx = neigh->dev->ifindex;
369 	int hash = addr_hash(addr, addr_len, ifidx);
370 
371 	if (neigh->dev->flags & IFF_LOOPBACK)
372 		lport = netdev2pinfo(physdev)->tx_chan + 4;
373 	else
374 		lport = netdev2pinfo(physdev)->lport;
375 
376 	if (neigh->dev->priv_flags & IFF_802_1Q_VLAN)
377 		vlan = vlan_dev_vlan_id(neigh->dev);
378 	else
379 		vlan = VLAN_NONE;
380 
381 	write_lock_bh(&d->lock);
382 	for (e = d->l2tab[hash].first; e; e = e->next)
383 		if (!addreq(e, addr) && e->ifindex == ifidx &&
384 		    e->vlan == vlan && e->lport == lport) {
385 			l2t_hold(d, e);
386 			if (atomic_read(&e->refcnt) == 1)
387 				reuse_entry(e, neigh);
388 			goto done;
389 		}
390 
391 	/* Need to allocate a new entry */
392 	e = alloc_l2e(d);
393 	if (e) {
394 		spin_lock(&e->lock);          /* avoid race with t4_l2t_free */
395 		e->state = L2T_STATE_RESOLVING;
396 		memcpy(e->addr, addr, addr_len);
397 		e->ifindex = ifidx;
398 		e->hash = hash;
399 		e->lport = lport;
400 		e->v6 = addr_len == 16;
401 		atomic_set(&e->refcnt, 1);
402 		neigh_replace(e, neigh);
403 		e->vlan = vlan;
404 		e->next = d->l2tab[hash].first;
405 		d->l2tab[hash].first = e;
406 		spin_unlock(&e->lock);
407 	}
408 done:
409 	write_unlock_bh(&d->lock);
410 	return e;
411 }
412 EXPORT_SYMBOL(cxgb4_l2t_get);
413 
414 /*
415  * Called when address resolution fails for an L2T entry to handle packets
416  * on the arpq head.  If a packet specifies a failure handler it is invoked,
417  * otherwise the packet is sent to the device.
418  */
419 static void handle_failed_resolution(struct adapter *adap, struct sk_buff *arpq)
420 {
421 	while (arpq) {
422 		struct sk_buff *skb = arpq;
423 		const struct l2t_skb_cb *cb = L2T_SKB_CB(skb);
424 
425 		arpq = skb->next;
426 		skb->next = NULL;
427 		if (cb->arp_err_handler)
428 			cb->arp_err_handler(cb->handle, skb);
429 		else
430 			t4_ofld_send(adap, skb);
431 	}
432 }
433 
434 /*
435  * Called when the host's neighbor layer makes a change to some entry that is
436  * loaded into the HW L2 table.
437  */
438 void t4_l2t_update(struct adapter *adap, struct neighbour *neigh)
439 {
440 	struct l2t_entry *e;
441 	struct sk_buff *arpq = NULL;
442 	struct l2t_data *d = adap->l2t;
443 	int addr_len = neigh->tbl->key_len;
444 	u32 *addr = (u32 *) neigh->primary_key;
445 	int ifidx = neigh->dev->ifindex;
446 	int hash = addr_hash(addr, addr_len, ifidx);
447 
448 	read_lock_bh(&d->lock);
449 	for (e = d->l2tab[hash].first; e; e = e->next)
450 		if (!addreq(e, addr) && e->ifindex == ifidx) {
451 			spin_lock(&e->lock);
452 			if (atomic_read(&e->refcnt))
453 				goto found;
454 			spin_unlock(&e->lock);
455 			break;
456 		}
457 	read_unlock_bh(&d->lock);
458 	return;
459 
460  found:
461 	read_unlock(&d->lock);
462 
463 	if (neigh != e->neigh)
464 		neigh_replace(e, neigh);
465 
466 	if (e->state == L2T_STATE_RESOLVING) {
467 		if (neigh->nud_state & NUD_FAILED) {
468 			arpq = e->arpq_head;
469 			e->arpq_head = e->arpq_tail = NULL;
470 		} else if ((neigh->nud_state & (NUD_CONNECTED | NUD_STALE)) &&
471 			   e->arpq_head) {
472 			write_l2e(adap, e, 1);
473 		}
474 	} else {
475 		e->state = neigh->nud_state & NUD_CONNECTED ?
476 			L2T_STATE_VALID : L2T_STATE_STALE;
477 		if (memcmp(e->dmac, neigh->ha, sizeof(e->dmac)))
478 			write_l2e(adap, e, 0);
479 	}
480 
481 	spin_unlock_bh(&e->lock);
482 
483 	if (arpq)
484 		handle_failed_resolution(adap, arpq);
485 }
486 
487 /* Allocate an L2T entry for use by a switching rule.  Such need to be
488  * explicitly freed and while busy they are not on any hash chain, so normal
489  * address resolution updates do not see them.
490  */
491 struct l2t_entry *t4_l2t_alloc_switching(struct l2t_data *d)
492 {
493 	struct l2t_entry *e;
494 
495 	write_lock_bh(&d->lock);
496 	e = alloc_l2e(d);
497 	if (e) {
498 		spin_lock(&e->lock);          /* avoid race with t4_l2t_free */
499 		e->state = L2T_STATE_SWITCHING;
500 		atomic_set(&e->refcnt, 1);
501 		spin_unlock(&e->lock);
502 	}
503 	write_unlock_bh(&d->lock);
504 	return e;
505 }
506 
507 /* Sets/updates the contents of a switching L2T entry that has been allocated
508  * with an earlier call to @t4_l2t_alloc_switching.
509  */
510 int t4_l2t_set_switching(struct adapter *adap, struct l2t_entry *e, u16 vlan,
511 		u8 port, u8 *eth_addr)
512 {
513 	e->vlan = vlan;
514 	e->lport = port;
515 	memcpy(e->dmac, eth_addr, ETH_ALEN);
516 	return write_l2e(adap, e, 0);
517 }
518 
519 struct l2t_data *t4_init_l2t(void)
520 {
521 	int i;
522 	struct l2t_data *d;
523 
524 	d = t4_alloc_mem(sizeof(*d));
525 	if (!d)
526 		return NULL;
527 
528 	d->rover = d->l2tab;
529 	atomic_set(&d->nfree, L2T_SIZE);
530 	rwlock_init(&d->lock);
531 
532 	for (i = 0; i < L2T_SIZE; ++i) {
533 		d->l2tab[i].idx = i;
534 		d->l2tab[i].state = L2T_STATE_UNUSED;
535 		spin_lock_init(&d->l2tab[i].lock);
536 		atomic_set(&d->l2tab[i].refcnt, 0);
537 	}
538 	return d;
539 }
540 
541 static inline void *l2t_get_idx(struct seq_file *seq, loff_t pos)
542 {
543 	struct l2t_entry *l2tab = seq->private;
544 
545 	return pos >= L2T_SIZE ? NULL : &l2tab[pos];
546 }
547 
548 static void *l2t_seq_start(struct seq_file *seq, loff_t *pos)
549 {
550 	return *pos ? l2t_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
551 }
552 
553 static void *l2t_seq_next(struct seq_file *seq, void *v, loff_t *pos)
554 {
555 	v = l2t_get_idx(seq, *pos);
556 	if (v)
557 		++*pos;
558 	return v;
559 }
560 
561 static void l2t_seq_stop(struct seq_file *seq, void *v)
562 {
563 }
564 
565 static char l2e_state(const struct l2t_entry *e)
566 {
567 	switch (e->state) {
568 	case L2T_STATE_VALID: return 'V';
569 	case L2T_STATE_STALE: return 'S';
570 	case L2T_STATE_SYNC_WRITE: return 'W';
571 	case L2T_STATE_RESOLVING: return e->arpq_head ? 'A' : 'R';
572 	case L2T_STATE_SWITCHING: return 'X';
573 	default:
574 		return 'U';
575 	}
576 }
577 
578 static int l2t_seq_show(struct seq_file *seq, void *v)
579 {
580 	if (v == SEQ_START_TOKEN)
581 		seq_puts(seq, " Idx IP address                "
582 			 "Ethernet address  VLAN/P LP State Users Port\n");
583 	else {
584 		char ip[60];
585 		struct l2t_entry *e = v;
586 
587 		spin_lock_bh(&e->lock);
588 		if (e->state == L2T_STATE_SWITCHING)
589 			ip[0] = '\0';
590 		else
591 			sprintf(ip, e->v6 ? "%pI6c" : "%pI4", e->addr);
592 		seq_printf(seq, "%4u %-25s %17pM %4d %u %2u   %c   %5u %s\n",
593 			   e->idx, ip, e->dmac,
594 			   e->vlan & VLAN_VID_MASK, vlan_prio(e), e->lport,
595 			   l2e_state(e), atomic_read(&e->refcnt),
596 			   e->neigh ? e->neigh->dev->name : "");
597 		spin_unlock_bh(&e->lock);
598 	}
599 	return 0;
600 }
601 
602 static const struct seq_operations l2t_seq_ops = {
603 	.start = l2t_seq_start,
604 	.next = l2t_seq_next,
605 	.stop = l2t_seq_stop,
606 	.show = l2t_seq_show
607 };
608 
609 static int l2t_seq_open(struct inode *inode, struct file *file)
610 {
611 	int rc = seq_open(file, &l2t_seq_ops);
612 
613 	if (!rc) {
614 		struct adapter *adap = inode->i_private;
615 		struct seq_file *seq = file->private_data;
616 
617 		seq->private = adap->l2t->l2tab;
618 	}
619 	return rc;
620 }
621 
622 const struct file_operations t4_l2t_fops = {
623 	.owner = THIS_MODULE,
624 	.open = l2t_seq_open,
625 	.read = seq_read,
626 	.llseek = seq_lseek,
627 	.release = seq_release,
628 };
629