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4d22de3e | 1 | /* |
a02d44a0 | 2 | * Copyright (c) 2003-2008 Chelsio, Inc. All rights reserved. |
4d22de3e DLR |
3 | * |
4 | * This software is available to you under a choice of one of two | |
5 | * licenses. You may choose to be licensed under the terms of the GNU | |
6 | * General Public License (GPL) Version 2, available from the file | |
7 | * COPYING in the main directory of this source tree, or the | |
8 | * OpenIB.org BSD license below: | |
9 | * | |
10 | * Redistribution and use in source and binary forms, with or | |
11 | * without modification, are permitted provided that the following | |
12 | * conditions are met: | |
13 | * | |
14 | * - Redistributions of source code must retain the above | |
15 | * copyright notice, this list of conditions and the following | |
16 | * disclaimer. | |
17 | * | |
18 | * - Redistributions in binary form must reproduce the above | |
19 | * copyright notice, this list of conditions and the following | |
20 | * disclaimer in the documentation and/or other materials | |
21 | * provided with the distribution. | |
22 | * | |
23 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | |
24 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | |
25 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | |
26 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS | |
27 | * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN | |
28 | * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
29 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
30 | * SOFTWARE. | |
31 | */ | |
32 | #include <linux/skbuff.h> | |
33 | #include <linux/netdevice.h> | |
34 | #include <linux/if.h> | |
35 | #include <linux/if_vlan.h> | |
36 | #include <linux/jhash.h> | |
5a0e3ad6 | 37 | #include <linux/slab.h> |
ee40fa06 | 38 | #include <linux/export.h> |
4d22de3e DLR |
39 | #include <net/neighbour.h> |
40 | #include "common.h" | |
41 | #include "t3cdev.h" | |
42 | #include "cxgb3_defs.h" | |
43 | #include "l2t.h" | |
44 | #include "t3_cpl.h" | |
45 | #include "firmware_exports.h" | |
46 | ||
47 | #define VLAN_NONE 0xfff | |
48 | ||
49 | /* | |
50 | * Module locking notes: There is a RW lock protecting the L2 table as a | |
51 | * whole plus a spinlock per L2T entry. Entry lookups and allocations happen | |
52 | * under the protection of the table lock, individual entry changes happen | |
53 | * while holding that entry's spinlock. The table lock nests outside the | |
54 | * entry locks. Allocations of new entries take the table lock as writers so | |
55 | * no other lookups can happen while allocating new entries. Entry updates | |
56 | * take the table lock as readers so multiple entries can be updated in | |
57 | * parallel. An L2T entry can be dropped by decrementing its reference count | |
58 | * and therefore can happen in parallel with entry allocation but no entry | |
59 | * can change state or increment its ref count during allocation as both of | |
60 | * these perform lookups. | |
61 | */ | |
62 | ||
63 | static inline unsigned int vlan_prio(const struct l2t_entry *e) | |
64 | { | |
65 | return e->vlan >> 13; | |
66 | } | |
67 | ||
68 | static inline unsigned int arp_hash(u32 key, int ifindex, | |
69 | const struct l2t_data *d) | |
70 | { | |
71 | return jhash_2words(key, ifindex, 0) & (d->nentries - 1); | |
72 | } | |
73 | ||
74 | static inline void neigh_replace(struct l2t_entry *e, struct neighbour *n) | |
75 | { | |
76 | neigh_hold(n); | |
77 | if (e->neigh) | |
78 | neigh_release(e->neigh); | |
79 | e->neigh = n; | |
80 | } | |
81 | ||
82 | /* | |
83 | * Set up an L2T entry and send any packets waiting in the arp queue. The | |
84 | * supplied skb is used for the CPL_L2T_WRITE_REQ. Must be called with the | |
85 | * entry locked. | |
86 | */ | |
87 | static int setup_l2e_send_pending(struct t3cdev *dev, struct sk_buff *skb, | |
88 | struct l2t_entry *e) | |
89 | { | |
90 | struct cpl_l2t_write_req *req; | |
147e70e6 | 91 | struct sk_buff *tmp; |
4d22de3e DLR |
92 | |
93 | if (!skb) { | |
94 | skb = alloc_skb(sizeof(*req), GFP_ATOMIC); | |
95 | if (!skb) | |
96 | return -ENOMEM; | |
97 | } | |
98 | ||
99 | req = (struct cpl_l2t_write_req *)__skb_put(skb, sizeof(*req)); | |
100 | req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_FORWARD)); | |
101 | OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_L2T_WRITE_REQ, e->idx)); | |
102 | req->params = htonl(V_L2T_W_IDX(e->idx) | V_L2T_W_IFF(e->smt_idx) | | |
103 | V_L2T_W_VLAN(e->vlan & VLAN_VID_MASK) | | |
104 | V_L2T_W_PRIO(vlan_prio(e))); | |
105 | memcpy(e->dmac, e->neigh->ha, sizeof(e->dmac)); | |
106 | memcpy(req->dst_mac, e->dmac, sizeof(req->dst_mac)); | |
107 | skb->priority = CPL_PRIORITY_CONTROL; | |
108 | cxgb3_ofld_send(dev, skb); | |
147e70e6 DM |
109 | |
110 | skb_queue_walk_safe(&e->arpq, skb, tmp) { | |
111 | __skb_unlink(skb, &e->arpq); | |
4d22de3e DLR |
112 | cxgb3_ofld_send(dev, skb); |
113 | } | |
4d22de3e DLR |
114 | e->state = L2T_STATE_VALID; |
115 | ||
116 | return 0; | |
117 | } | |
118 | ||
119 | /* | |
120 | * Add a packet to the an L2T entry's queue of packets awaiting resolution. | |
121 | * Must be called with the entry's lock held. | |
122 | */ | |
123 | static inline void arpq_enqueue(struct l2t_entry *e, struct sk_buff *skb) | |
124 | { | |
147e70e6 | 125 | __skb_queue_tail(&e->arpq, skb); |
4d22de3e DLR |
126 | } |
127 | ||
128 | int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb, | |
129 | struct l2t_entry *e) | |
130 | { | |
131 | again: | |
132 | switch (e->state) { | |
133 | case L2T_STATE_STALE: /* entry is stale, kick off revalidation */ | |
134 | neigh_event_send(e->neigh, NULL); | |
135 | spin_lock_bh(&e->lock); | |
136 | if (e->state == L2T_STATE_STALE) | |
137 | e->state = L2T_STATE_VALID; | |
138 | spin_unlock_bh(&e->lock); | |
139 | case L2T_STATE_VALID: /* fast-path, send the packet on */ | |
140 | return cxgb3_ofld_send(dev, skb); | |
141 | case L2T_STATE_RESOLVING: | |
142 | spin_lock_bh(&e->lock); | |
143 | if (e->state != L2T_STATE_RESOLVING) { | |
144 | /* ARP already completed */ | |
145 | spin_unlock_bh(&e->lock); | |
146 | goto again; | |
147 | } | |
148 | arpq_enqueue(e, skb); | |
149 | spin_unlock_bh(&e->lock); | |
150 | ||
151 | /* | |
152 | * Only the first packet added to the arpq should kick off | |
153 | * resolution. However, because the alloc_skb below can fail, | |
154 | * we allow each packet added to the arpq to retry resolution | |
155 | * as a way of recovering from transient memory exhaustion. | |
156 | * A better way would be to use a work request to retry L2T | |
157 | * entries when there's no memory. | |
158 | */ | |
159 | if (!neigh_event_send(e->neigh, NULL)) { | |
160 | skb = alloc_skb(sizeof(struct cpl_l2t_write_req), | |
161 | GFP_ATOMIC); | |
162 | if (!skb) | |
163 | break; | |
164 | ||
165 | spin_lock_bh(&e->lock); | |
147e70e6 | 166 | if (!skb_queue_empty(&e->arpq)) |
4d22de3e DLR |
167 | setup_l2e_send_pending(dev, skb, e); |
168 | else /* we lost the race */ | |
169 | __kfree_skb(skb); | |
170 | spin_unlock_bh(&e->lock); | |
171 | } | |
172 | } | |
173 | return 0; | |
174 | } | |
175 | ||
176 | EXPORT_SYMBOL(t3_l2t_send_slow); | |
177 | ||
178 | void t3_l2t_send_event(struct t3cdev *dev, struct l2t_entry *e) | |
179 | { | |
180 | again: | |
181 | switch (e->state) { | |
182 | case L2T_STATE_STALE: /* entry is stale, kick off revalidation */ | |
183 | neigh_event_send(e->neigh, NULL); | |
184 | spin_lock_bh(&e->lock); | |
185 | if (e->state == L2T_STATE_STALE) { | |
186 | e->state = L2T_STATE_VALID; | |
187 | } | |
188 | spin_unlock_bh(&e->lock); | |
189 | return; | |
190 | case L2T_STATE_VALID: /* fast-path, send the packet on */ | |
191 | return; | |
192 | case L2T_STATE_RESOLVING: | |
193 | spin_lock_bh(&e->lock); | |
194 | if (e->state != L2T_STATE_RESOLVING) { | |
195 | /* ARP already completed */ | |
196 | spin_unlock_bh(&e->lock); | |
197 | goto again; | |
198 | } | |
199 | spin_unlock_bh(&e->lock); | |
200 | ||
201 | /* | |
202 | * Only the first packet added to the arpq should kick off | |
203 | * resolution. However, because the alloc_skb below can fail, | |
204 | * we allow each packet added to the arpq to retry resolution | |
205 | * as a way of recovering from transient memory exhaustion. | |
206 | * A better way would be to use a work request to retry L2T | |
207 | * entries when there's no memory. | |
208 | */ | |
209 | neigh_event_send(e->neigh, NULL); | |
210 | } | |
4d22de3e DLR |
211 | } |
212 | ||
213 | EXPORT_SYMBOL(t3_l2t_send_event); | |
214 | ||
215 | /* | |
216 | * Allocate a free L2T entry. Must be called with l2t_data.lock held. | |
217 | */ | |
218 | static struct l2t_entry *alloc_l2e(struct l2t_data *d) | |
219 | { | |
220 | struct l2t_entry *end, *e, **p; | |
221 | ||
222 | if (!atomic_read(&d->nfree)) | |
223 | return NULL; | |
224 | ||
225 | /* there's definitely a free entry */ | |
226 | for (e = d->rover, end = &d->l2tab[d->nentries]; e != end; ++e) | |
227 | if (atomic_read(&e->refcnt) == 0) | |
228 | goto found; | |
229 | ||
230 | for (e = &d->l2tab[1]; atomic_read(&e->refcnt); ++e) ; | |
231 | found: | |
232 | d->rover = e + 1; | |
233 | atomic_dec(&d->nfree); | |
234 | ||
235 | /* | |
236 | * The entry we found may be an inactive entry that is | |
237 | * presently in the hash table. We need to remove it. | |
238 | */ | |
239 | if (e->state != L2T_STATE_UNUSED) { | |
240 | int hash = arp_hash(e->addr, e->ifindex, d); | |
241 | ||
242 | for (p = &d->l2tab[hash].first; *p; p = &(*p)->next) | |
243 | if (*p == e) { | |
244 | *p = e->next; | |
245 | break; | |
246 | } | |
247 | e->state = L2T_STATE_UNUSED; | |
248 | } | |
249 | return e; | |
250 | } | |
251 | ||
252 | /* | |
253 | * Called when an L2T entry has no more users. The entry is left in the hash | |
254 | * table since it is likely to be reused but we also bump nfree to indicate | |
255 | * that the entry can be reallocated for a different neighbor. We also drop | |
256 | * the existing neighbor reference in case the neighbor is going away and is | |
257 | * waiting on our reference. | |
258 | * | |
259 | * Because entries can be reallocated to other neighbors once their ref count | |
260 | * drops to 0 we need to take the entry's lock to avoid races with a new | |
261 | * incarnation. | |
262 | */ | |
263 | void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e) | |
264 | { | |
265 | spin_lock_bh(&e->lock); | |
266 | if (atomic_read(&e->refcnt) == 0) { /* hasn't been recycled */ | |
267 | if (e->neigh) { | |
268 | neigh_release(e->neigh); | |
269 | e->neigh = NULL; | |
270 | } | |
271 | } | |
272 | spin_unlock_bh(&e->lock); | |
273 | atomic_inc(&d->nfree); | |
274 | } | |
275 | ||
276 | EXPORT_SYMBOL(t3_l2e_free); | |
277 | ||
278 | /* | |
279 | * Update an L2T entry that was previously used for the same next hop as neigh. | |
280 | * Must be called with softirqs disabled. | |
281 | */ | |
282 | static inline void reuse_entry(struct l2t_entry *e, struct neighbour *neigh) | |
283 | { | |
284 | unsigned int nud_state; | |
285 | ||
286 | spin_lock(&e->lock); /* avoid race with t3_l2t_free */ | |
287 | ||
288 | if (neigh != e->neigh) | |
289 | neigh_replace(e, neigh); | |
290 | nud_state = neigh->nud_state; | |
291 | if (memcmp(e->dmac, neigh->ha, sizeof(e->dmac)) || | |
292 | !(nud_state & NUD_VALID)) | |
293 | e->state = L2T_STATE_RESOLVING; | |
294 | else if (nud_state & NUD_CONNECTED) | |
295 | e->state = L2T_STATE_VALID; | |
296 | else | |
297 | e->state = L2T_STATE_STALE; | |
298 | spin_unlock(&e->lock); | |
299 | } | |
300 | ||
a4757123 | 301 | struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct dst_entry *dst, |
4d22de3e DLR |
302 | struct net_device *dev) |
303 | { | |
e48f129c | 304 | struct l2t_entry *e = NULL; |
a4757123 DM |
305 | struct neighbour *neigh; |
306 | struct port_info *p; | |
e48f129c NH |
307 | struct l2t_data *d; |
308 | int hash; | |
a4757123 DM |
309 | u32 addr; |
310 | int ifidx; | |
311 | int smt_idx; | |
4d22de3e | 312 | |
e48f129c | 313 | rcu_read_lock(); |
a4757123 DM |
314 | neigh = dst_get_neighbour_noref(dst); |
315 | if (!neigh) | |
316 | goto done_rcu; | |
317 | ||
318 | addr = *(u32 *) neigh->primary_key; | |
319 | ifidx = neigh->dev->ifindex; | |
320 | ||
321 | if (!dev) | |
322 | dev = neigh->dev; | |
323 | p = netdev_priv(dev); | |
324 | smt_idx = p->port_id; | |
325 | ||
e48f129c NH |
326 | d = L2DATA(cdev); |
327 | if (!d) | |
328 | goto done_rcu; | |
329 | ||
330 | hash = arp_hash(addr, ifidx, d); | |
331 | ||
4d22de3e DLR |
332 | write_lock_bh(&d->lock); |
333 | for (e = d->l2tab[hash].first; e; e = e->next) | |
334 | if (e->addr == addr && e->ifindex == ifidx && | |
335 | e->smt_idx == smt_idx) { | |
336 | l2t_hold(d, e); | |
337 | if (atomic_read(&e->refcnt) == 1) | |
338 | reuse_entry(e, neigh); | |
a4757123 | 339 | goto done_unlock; |
4d22de3e DLR |
340 | } |
341 | ||
342 | /* Need to allocate a new entry */ | |
343 | e = alloc_l2e(d); | |
344 | if (e) { | |
345 | spin_lock(&e->lock); /* avoid race with t3_l2t_free */ | |
346 | e->next = d->l2tab[hash].first; | |
347 | d->l2tab[hash].first = e; | |
348 | e->state = L2T_STATE_RESOLVING; | |
349 | e->addr = addr; | |
350 | e->ifindex = ifidx; | |
351 | e->smt_idx = smt_idx; | |
352 | atomic_set(&e->refcnt, 1); | |
353 | neigh_replace(e, neigh); | |
354 | if (neigh->dev->priv_flags & IFF_802_1Q_VLAN) | |
22d1ba74 | 355 | e->vlan = vlan_dev_vlan_id(neigh->dev); |
4d22de3e DLR |
356 | else |
357 | e->vlan = VLAN_NONE; | |
358 | spin_unlock(&e->lock); | |
359 | } | |
a4757123 | 360 | done_unlock: |
4d22de3e | 361 | write_unlock_bh(&d->lock); |
e48f129c NH |
362 | done_rcu: |
363 | rcu_read_unlock(); | |
4d22de3e DLR |
364 | return e; |
365 | } | |
366 | ||
367 | EXPORT_SYMBOL(t3_l2t_get); | |
368 | ||
369 | /* | |
370 | * Called when address resolution fails for an L2T entry to handle packets | |
371 | * on the arpq head. If a packet specifies a failure handler it is invoked, | |
372 | * otherwise the packets is sent to the offload device. | |
373 | * | |
374 | * XXX: maybe we should abandon the latter behavior and just require a failure | |
375 | * handler. | |
376 | */ | |
147e70e6 | 377 | static void handle_failed_resolution(struct t3cdev *dev, struct sk_buff_head *arpq) |
4d22de3e | 378 | { |
147e70e6 DM |
379 | struct sk_buff *skb, *tmp; |
380 | ||
381 | skb_queue_walk_safe(arpq, skb, tmp) { | |
4d22de3e DLR |
382 | struct l2t_skb_cb *cb = L2T_SKB_CB(skb); |
383 | ||
147e70e6 | 384 | __skb_unlink(skb, arpq); |
4d22de3e DLR |
385 | if (cb->arp_failure_handler) |
386 | cb->arp_failure_handler(dev, skb); | |
387 | else | |
388 | cxgb3_ofld_send(dev, skb); | |
389 | } | |
390 | } | |
391 | ||
392 | /* | |
393 | * Called when the host's ARP layer makes a change to some entry that is | |
394 | * loaded into the HW L2 table. | |
395 | */ | |
396 | void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh) | |
397 | { | |
147e70e6 | 398 | struct sk_buff_head arpq; |
4d22de3e | 399 | struct l2t_entry *e; |
4d22de3e DLR |
400 | struct l2t_data *d = L2DATA(dev); |
401 | u32 addr = *(u32 *) neigh->primary_key; | |
402 | int ifidx = neigh->dev->ifindex; | |
403 | int hash = arp_hash(addr, ifidx, d); | |
404 | ||
405 | read_lock_bh(&d->lock); | |
406 | for (e = d->l2tab[hash].first; e; e = e->next) | |
407 | if (e->addr == addr && e->ifindex == ifidx) { | |
408 | spin_lock(&e->lock); | |
409 | goto found; | |
410 | } | |
411 | read_unlock_bh(&d->lock); | |
412 | return; | |
413 | ||
414 | found: | |
147e70e6 DM |
415 | __skb_queue_head_init(&arpq); |
416 | ||
4d22de3e DLR |
417 | read_unlock(&d->lock); |
418 | if (atomic_read(&e->refcnt)) { | |
419 | if (neigh != e->neigh) | |
420 | neigh_replace(e, neigh); | |
421 | ||
422 | if (e->state == L2T_STATE_RESOLVING) { | |
423 | if (neigh->nud_state & NUD_FAILED) { | |
147e70e6 | 424 | skb_queue_splice_init(&e->arpq, &arpq); |
4eb61e02 | 425 | } else if (neigh->nud_state & (NUD_CONNECTED|NUD_STALE)) |
4d22de3e DLR |
426 | setup_l2e_send_pending(dev, NULL, e); |
427 | } else { | |
8082c37c | 428 | e->state = neigh->nud_state & NUD_CONNECTED ? |
4d22de3e DLR |
429 | L2T_STATE_VALID : L2T_STATE_STALE; |
430 | if (memcmp(e->dmac, neigh->ha, 6)) | |
431 | setup_l2e_send_pending(dev, NULL, e); | |
432 | } | |
433 | } | |
434 | spin_unlock_bh(&e->lock); | |
435 | ||
147e70e6 DM |
436 | if (!skb_queue_empty(&arpq)) |
437 | handle_failed_resolution(dev, &arpq); | |
4d22de3e DLR |
438 | } |
439 | ||
440 | struct l2t_data *t3_init_l2t(unsigned int l2t_capacity) | |
441 | { | |
442 | struct l2t_data *d; | |
443 | int i, size = sizeof(*d) + l2t_capacity * sizeof(struct l2t_entry); | |
444 | ||
445 | d = cxgb_alloc_mem(size); | |
446 | if (!d) | |
447 | return NULL; | |
448 | ||
449 | d->nentries = l2t_capacity; | |
450 | d->rover = &d->l2tab[1]; /* entry 0 is not used */ | |
451 | atomic_set(&d->nfree, l2t_capacity - 1); | |
452 | rwlock_init(&d->lock); | |
453 | ||
454 | for (i = 0; i < l2t_capacity; ++i) { | |
455 | d->l2tab[i].idx = i; | |
456 | d->l2tab[i].state = L2T_STATE_UNUSED; | |
6d329af9 | 457 | __skb_queue_head_init(&d->l2tab[i].arpq); |
4d22de3e DLR |
458 | spin_lock_init(&d->l2tab[i].lock); |
459 | atomic_set(&d->l2tab[i].refcnt, 0); | |
460 | } | |
461 | return d; | |
462 | } | |
463 | ||
464 | void t3_free_l2t(struct l2t_data *d) | |
465 | { | |
466 | cxgb_free_mem(d); | |
467 | } | |
468 |