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xen-netback: include definition of csum_ipv6_magic
[deliverable/linux.git] / drivers / net / xen-netback / netback.c
1 /*
2 * Back-end of the driver for virtual network devices. This portion of the
3 * driver exports a 'unified' network-device interface that can be accessed
4 * by any operating system that implements a compatible front end. A
5 * reference front-end implementation can be found in:
6 * drivers/net/xen-netfront.c
7 *
8 * Copyright (c) 2002-2005, K A Fraser
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 * IN THE SOFTWARE.
33 */
34
35 #include "common.h"
36
37 #include <linux/kthread.h>
38 #include <linux/if_vlan.h>
39 #include <linux/udp.h>
40
41 #include <net/tcp.h>
42 #include <net/ip6_checksum.h>
43
44 #include <xen/xen.h>
45 #include <xen/events.h>
46 #include <xen/interface/memory.h>
47
48 #include <asm/xen/hypercall.h>
49 #include <asm/xen/page.h>
50
51 /* Provide an option to disable split event channels at load time as
52 * event channels are limited resource. Split event channels are
53 * enabled by default.
54 */
55 bool separate_tx_rx_irq = 1;
56 module_param(separate_tx_rx_irq, bool, 0644);
57
58 /*
59 * This is the maximum slots a skb can have. If a guest sends a skb
60 * which exceeds this limit it is considered malicious.
61 */
62 #define FATAL_SKB_SLOTS_DEFAULT 20
63 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
64 module_param(fatal_skb_slots, uint, 0444);
65
66 /*
67 * To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
68 * the maximum slots a valid packet can use. Now this value is defined
69 * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
70 * all backend.
71 */
72 #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
73
74 /*
75 * If head != INVALID_PENDING_RING_IDX, it means this tx request is head of
76 * one or more merged tx requests, otherwise it is the continuation of
77 * previous tx request.
78 */
79 static inline int pending_tx_is_head(struct xenvif *vif, RING_IDX idx)
80 {
81 return vif->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
82 }
83
84 static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
85 u8 status);
86
87 static void make_tx_response(struct xenvif *vif,
88 struct xen_netif_tx_request *txp,
89 s8 st);
90
91 static inline int tx_work_todo(struct xenvif *vif);
92 static inline int rx_work_todo(struct xenvif *vif);
93
94 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
95 u16 id,
96 s8 st,
97 u16 offset,
98 u16 size,
99 u16 flags);
100
101 static inline unsigned long idx_to_pfn(struct xenvif *vif,
102 u16 idx)
103 {
104 return page_to_pfn(vif->mmap_pages[idx]);
105 }
106
107 static inline unsigned long idx_to_kaddr(struct xenvif *vif,
108 u16 idx)
109 {
110 return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
111 }
112
113 /* This is a miniumum size for the linear area to avoid lots of
114 * calls to __pskb_pull_tail() as we set up checksum offsets. The
115 * value 128 was chosen as it covers all IPv4 and most likely
116 * IPv6 headers.
117 */
118 #define PKT_PROT_LEN 128
119
120 static u16 frag_get_pending_idx(skb_frag_t *frag)
121 {
122 return (u16)frag->page_offset;
123 }
124
125 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
126 {
127 frag->page_offset = pending_idx;
128 }
129
130 static inline pending_ring_idx_t pending_index(unsigned i)
131 {
132 return i & (MAX_PENDING_REQS-1);
133 }
134
135 static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
136 {
137 return MAX_PENDING_REQS -
138 vif->pending_prod + vif->pending_cons;
139 }
140
141 static int max_required_rx_slots(struct xenvif *vif)
142 {
143 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
144
145 /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */
146 if (vif->can_sg || vif->gso_mask || vif->gso_prefix_mask)
147 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
148
149 return max;
150 }
151
152 int xenvif_rx_ring_full(struct xenvif *vif)
153 {
154 RING_IDX peek = vif->rx_req_cons_peek;
155 RING_IDX needed = max_required_rx_slots(vif);
156
157 return ((vif->rx.sring->req_prod - peek) < needed) ||
158 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
159 }
160
161 int xenvif_must_stop_queue(struct xenvif *vif)
162 {
163 if (!xenvif_rx_ring_full(vif))
164 return 0;
165
166 vif->rx.sring->req_event = vif->rx_req_cons_peek +
167 max_required_rx_slots(vif);
168 mb(); /* request notification /then/ check the queue */
169
170 return xenvif_rx_ring_full(vif);
171 }
172
173 /*
174 * Returns true if we should start a new receive buffer instead of
175 * adding 'size' bytes to a buffer which currently contains 'offset'
176 * bytes.
177 */
178 static bool start_new_rx_buffer(int offset, unsigned long size, int head)
179 {
180 /* simple case: we have completely filled the current buffer. */
181 if (offset == MAX_BUFFER_OFFSET)
182 return true;
183
184 /*
185 * complex case: start a fresh buffer if the current frag
186 * would overflow the current buffer but only if:
187 * (i) this frag would fit completely in the next buffer
188 * and (ii) there is already some data in the current buffer
189 * and (iii) this is not the head buffer.
190 *
191 * Where:
192 * - (i) stops us splitting a frag into two copies
193 * unless the frag is too large for a single buffer.
194 * - (ii) stops us from leaving a buffer pointlessly empty.
195 * - (iii) stops us leaving the first buffer
196 * empty. Strictly speaking this is already covered
197 * by (ii) but is explicitly checked because
198 * netfront relies on the first buffer being
199 * non-empty and can crash otherwise.
200 *
201 * This means we will effectively linearise small
202 * frags but do not needlessly split large buffers
203 * into multiple copies tend to give large frags their
204 * own buffers as before.
205 */
206 if ((offset + size > MAX_BUFFER_OFFSET) &&
207 (size <= MAX_BUFFER_OFFSET) && offset && !head)
208 return true;
209
210 return false;
211 }
212
213 struct xenvif_count_slot_state {
214 unsigned long copy_off;
215 bool head;
216 };
217
218 unsigned int xenvif_count_frag_slots(struct xenvif *vif,
219 unsigned long offset, unsigned long size,
220 struct xenvif_count_slot_state *state)
221 {
222 unsigned count = 0;
223
224 offset &= ~PAGE_MASK;
225
226 while (size > 0) {
227 unsigned long bytes;
228
229 bytes = PAGE_SIZE - offset;
230
231 if (bytes > size)
232 bytes = size;
233
234 if (start_new_rx_buffer(state->copy_off, bytes, state->head)) {
235 count++;
236 state->copy_off = 0;
237 }
238
239 if (state->copy_off + bytes > MAX_BUFFER_OFFSET)
240 bytes = MAX_BUFFER_OFFSET - state->copy_off;
241
242 state->copy_off += bytes;
243
244 offset += bytes;
245 size -= bytes;
246
247 if (offset == PAGE_SIZE)
248 offset = 0;
249
250 state->head = false;
251 }
252
253 return count;
254 }
255
256 /*
257 * Figure out how many ring slots we're going to need to send @skb to
258 * the guest. This function is essentially a dry run of
259 * xenvif_gop_frag_copy.
260 */
261 unsigned int xenvif_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
262 {
263 struct xenvif_count_slot_state state;
264 unsigned int count;
265 unsigned char *data;
266 unsigned i;
267
268 state.head = true;
269 state.copy_off = 0;
270
271 /* Slot for the first (partial) page of data. */
272 count = 1;
273
274 /* Need a slot for the GSO prefix for GSO extra data? */
275 if (skb_shinfo(skb)->gso_size)
276 count++;
277
278 data = skb->data;
279 while (data < skb_tail_pointer(skb)) {
280 unsigned long offset = offset_in_page(data);
281 unsigned long size = PAGE_SIZE - offset;
282
283 if (data + size > skb_tail_pointer(skb))
284 size = skb_tail_pointer(skb) - data;
285
286 count += xenvif_count_frag_slots(vif, offset, size, &state);
287
288 data += size;
289 }
290
291 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
292 unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
293 unsigned long offset = skb_shinfo(skb)->frags[i].page_offset;
294
295 count += xenvif_count_frag_slots(vif, offset, size, &state);
296 }
297 return count;
298 }
299
300 struct netrx_pending_operations {
301 unsigned copy_prod, copy_cons;
302 unsigned meta_prod, meta_cons;
303 struct gnttab_copy *copy;
304 struct xenvif_rx_meta *meta;
305 int copy_off;
306 grant_ref_t copy_gref;
307 };
308
309 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif,
310 struct netrx_pending_operations *npo)
311 {
312 struct xenvif_rx_meta *meta;
313 struct xen_netif_rx_request *req;
314
315 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
316
317 meta = npo->meta + npo->meta_prod++;
318 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
319 meta->gso_size = 0;
320 meta->size = 0;
321 meta->id = req->id;
322
323 npo->copy_off = 0;
324 npo->copy_gref = req->gref;
325
326 return meta;
327 }
328
329 /*
330 * Set up the grant operations for this fragment. If it's a flipping
331 * interface, we also set up the unmap request from here.
332 */
333 static void xenvif_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
334 struct netrx_pending_operations *npo,
335 struct page *page, unsigned long size,
336 unsigned long offset, int *head)
337 {
338 struct gnttab_copy *copy_gop;
339 struct xenvif_rx_meta *meta;
340 unsigned long bytes;
341 int gso_type;
342
343 /* Data must not cross a page boundary. */
344 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
345
346 meta = npo->meta + npo->meta_prod - 1;
347
348 /* Skip unused frames from start of page */
349 page += offset >> PAGE_SHIFT;
350 offset &= ~PAGE_MASK;
351
352 while (size > 0) {
353 BUG_ON(offset >= PAGE_SIZE);
354 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
355
356 bytes = PAGE_SIZE - offset;
357
358 if (bytes > size)
359 bytes = size;
360
361 if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
362 /*
363 * Netfront requires there to be some data in the head
364 * buffer.
365 */
366 BUG_ON(*head);
367
368 meta = get_next_rx_buffer(vif, npo);
369 }
370
371 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
372 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
373
374 copy_gop = npo->copy + npo->copy_prod++;
375 copy_gop->flags = GNTCOPY_dest_gref;
376 copy_gop->len = bytes;
377
378 copy_gop->source.domid = DOMID_SELF;
379 copy_gop->source.u.gmfn = virt_to_mfn(page_address(page));
380 copy_gop->source.offset = offset;
381
382 copy_gop->dest.domid = vif->domid;
383 copy_gop->dest.offset = npo->copy_off;
384 copy_gop->dest.u.ref = npo->copy_gref;
385
386 npo->copy_off += bytes;
387 meta->size += bytes;
388
389 offset += bytes;
390 size -= bytes;
391
392 /* Next frame */
393 if (offset == PAGE_SIZE && size) {
394 BUG_ON(!PageCompound(page));
395 page++;
396 offset = 0;
397 }
398
399 /* Leave a gap for the GSO descriptor. */
400 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
401 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
402 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
403 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
404 else
405 gso_type = XEN_NETIF_GSO_TYPE_NONE;
406
407 if (*head && ((1 << gso_type) & vif->gso_mask))
408 vif->rx.req_cons++;
409
410 *head = 0; /* There must be something in this buffer now. */
411
412 }
413 }
414
415 /*
416 * Prepare an SKB to be transmitted to the frontend.
417 *
418 * This function is responsible for allocating grant operations, meta
419 * structures, etc.
420 *
421 * It returns the number of meta structures consumed. The number of
422 * ring slots used is always equal to the number of meta slots used
423 * plus the number of GSO descriptors used. Currently, we use either
424 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
425 * frontend-side LRO).
426 */
427 static int xenvif_gop_skb(struct sk_buff *skb,
428 struct netrx_pending_operations *npo)
429 {
430 struct xenvif *vif = netdev_priv(skb->dev);
431 int nr_frags = skb_shinfo(skb)->nr_frags;
432 int i;
433 struct xen_netif_rx_request *req;
434 struct xenvif_rx_meta *meta;
435 unsigned char *data;
436 int head = 1;
437 int old_meta_prod;
438 int gso_type;
439 int gso_size;
440
441 old_meta_prod = npo->meta_prod;
442
443 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) {
444 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
445 gso_size = skb_shinfo(skb)->gso_size;
446 } else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) {
447 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
448 gso_size = skb_shinfo(skb)->gso_size;
449 } else {
450 gso_type = XEN_NETIF_GSO_TYPE_NONE;
451 gso_size = 0;
452 }
453
454 /* Set up a GSO prefix descriptor, if necessary */
455 if ((1 << skb_shinfo(skb)->gso_type) & vif->gso_prefix_mask) {
456 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
457 meta = npo->meta + npo->meta_prod++;
458 meta->gso_type = gso_type;
459 meta->gso_size = gso_size;
460 meta->size = 0;
461 meta->id = req->id;
462 }
463
464 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
465 meta = npo->meta + npo->meta_prod++;
466
467 if ((1 << gso_type) & vif->gso_mask) {
468 meta->gso_type = gso_type;
469 meta->gso_size = gso_size;
470 } else {
471 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
472 meta->gso_size = 0;
473 }
474
475 meta->size = 0;
476 meta->id = req->id;
477 npo->copy_off = 0;
478 npo->copy_gref = req->gref;
479
480 data = skb->data;
481 while (data < skb_tail_pointer(skb)) {
482 unsigned int offset = offset_in_page(data);
483 unsigned int len = PAGE_SIZE - offset;
484
485 if (data + len > skb_tail_pointer(skb))
486 len = skb_tail_pointer(skb) - data;
487
488 xenvif_gop_frag_copy(vif, skb, npo,
489 virt_to_page(data), len, offset, &head);
490 data += len;
491 }
492
493 for (i = 0; i < nr_frags; i++) {
494 xenvif_gop_frag_copy(vif, skb, npo,
495 skb_frag_page(&skb_shinfo(skb)->frags[i]),
496 skb_frag_size(&skb_shinfo(skb)->frags[i]),
497 skb_shinfo(skb)->frags[i].page_offset,
498 &head);
499 }
500
501 return npo->meta_prod - old_meta_prod;
502 }
503
504 /*
505 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
506 * used to set up the operations on the top of
507 * netrx_pending_operations, which have since been done. Check that
508 * they didn't give any errors and advance over them.
509 */
510 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
511 struct netrx_pending_operations *npo)
512 {
513 struct gnttab_copy *copy_op;
514 int status = XEN_NETIF_RSP_OKAY;
515 int i;
516
517 for (i = 0; i < nr_meta_slots; i++) {
518 copy_op = npo->copy + npo->copy_cons++;
519 if (copy_op->status != GNTST_okay) {
520 netdev_dbg(vif->dev,
521 "Bad status %d from copy to DOM%d.\n",
522 copy_op->status, vif->domid);
523 status = XEN_NETIF_RSP_ERROR;
524 }
525 }
526
527 return status;
528 }
529
530 static void xenvif_add_frag_responses(struct xenvif *vif, int status,
531 struct xenvif_rx_meta *meta,
532 int nr_meta_slots)
533 {
534 int i;
535 unsigned long offset;
536
537 /* No fragments used */
538 if (nr_meta_slots <= 1)
539 return;
540
541 nr_meta_slots--;
542
543 for (i = 0; i < nr_meta_slots; i++) {
544 int flags;
545 if (i == nr_meta_slots - 1)
546 flags = 0;
547 else
548 flags = XEN_NETRXF_more_data;
549
550 offset = 0;
551 make_rx_response(vif, meta[i].id, status, offset,
552 meta[i].size, flags);
553 }
554 }
555
556 struct skb_cb_overlay {
557 int meta_slots_used;
558 };
559
560 static void xenvif_kick_thread(struct xenvif *vif)
561 {
562 wake_up(&vif->wq);
563 }
564
565 void xenvif_rx_action(struct xenvif *vif)
566 {
567 s8 status;
568 u16 flags;
569 struct xen_netif_rx_response *resp;
570 struct sk_buff_head rxq;
571 struct sk_buff *skb;
572 LIST_HEAD(notify);
573 int ret;
574 int nr_frags;
575 int count;
576 unsigned long offset;
577 struct skb_cb_overlay *sco;
578 int need_to_notify = 0;
579
580 struct netrx_pending_operations npo = {
581 .copy = vif->grant_copy_op,
582 .meta = vif->meta,
583 };
584
585 skb_queue_head_init(&rxq);
586
587 count = 0;
588
589 while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
590 vif = netdev_priv(skb->dev);
591 nr_frags = skb_shinfo(skb)->nr_frags;
592
593 sco = (struct skb_cb_overlay *)skb->cb;
594 sco->meta_slots_used = xenvif_gop_skb(skb, &npo);
595
596 count += nr_frags + 1;
597
598 __skb_queue_tail(&rxq, skb);
599
600 /* Filled the batch queue? */
601 /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */
602 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
603 break;
604 }
605
606 BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta));
607
608 if (!npo.copy_prod)
609 return;
610
611 BUG_ON(npo.copy_prod > ARRAY_SIZE(vif->grant_copy_op));
612 gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod);
613
614 while ((skb = __skb_dequeue(&rxq)) != NULL) {
615 sco = (struct skb_cb_overlay *)skb->cb;
616
617 vif = netdev_priv(skb->dev);
618
619 if ((1 << vif->meta[npo.meta_cons].gso_type) &
620 vif->gso_prefix_mask) {
621 resp = RING_GET_RESPONSE(&vif->rx,
622 vif->rx.rsp_prod_pvt++);
623
624 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
625
626 resp->offset = vif->meta[npo.meta_cons].gso_size;
627 resp->id = vif->meta[npo.meta_cons].id;
628 resp->status = sco->meta_slots_used;
629
630 npo.meta_cons++;
631 sco->meta_slots_used--;
632 }
633
634
635 vif->dev->stats.tx_bytes += skb->len;
636 vif->dev->stats.tx_packets++;
637
638 status = xenvif_check_gop(vif, sco->meta_slots_used, &npo);
639
640 if (sco->meta_slots_used == 1)
641 flags = 0;
642 else
643 flags = XEN_NETRXF_more_data;
644
645 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
646 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
647 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
648 /* remote but checksummed. */
649 flags |= XEN_NETRXF_data_validated;
650
651 offset = 0;
652 resp = make_rx_response(vif, vif->meta[npo.meta_cons].id,
653 status, offset,
654 vif->meta[npo.meta_cons].size,
655 flags);
656
657 if ((1 << vif->meta[npo.meta_cons].gso_type) &
658 vif->gso_mask) {
659 struct xen_netif_extra_info *gso =
660 (struct xen_netif_extra_info *)
661 RING_GET_RESPONSE(&vif->rx,
662 vif->rx.rsp_prod_pvt++);
663
664 resp->flags |= XEN_NETRXF_extra_info;
665
666 gso->u.gso.type = vif->meta[npo.meta_cons].gso_type;
667 gso->u.gso.size = vif->meta[npo.meta_cons].gso_size;
668 gso->u.gso.pad = 0;
669 gso->u.gso.features = 0;
670
671 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
672 gso->flags = 0;
673 }
674
675 xenvif_add_frag_responses(vif, status,
676 vif->meta + npo.meta_cons + 1,
677 sco->meta_slots_used);
678
679 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
680
681 if (ret)
682 need_to_notify = 1;
683
684 xenvif_notify_tx_completion(vif);
685
686 npo.meta_cons += sco->meta_slots_used;
687 dev_kfree_skb(skb);
688 }
689
690 if (need_to_notify)
691 notify_remote_via_irq(vif->rx_irq);
692
693 /* More work to do? */
694 if (!skb_queue_empty(&vif->rx_queue))
695 xenvif_kick_thread(vif);
696 }
697
698 void xenvif_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
699 {
700 skb_queue_tail(&vif->rx_queue, skb);
701
702 xenvif_kick_thread(vif);
703 }
704
705 void xenvif_check_rx_xenvif(struct xenvif *vif)
706 {
707 int more_to_do;
708
709 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
710
711 if (more_to_do)
712 napi_schedule(&vif->napi);
713 }
714
715 static void tx_add_credit(struct xenvif *vif)
716 {
717 unsigned long max_burst, max_credit;
718
719 /*
720 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
721 * Otherwise the interface can seize up due to insufficient credit.
722 */
723 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
724 max_burst = min(max_burst, 131072UL);
725 max_burst = max(max_burst, vif->credit_bytes);
726
727 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
728 max_credit = vif->remaining_credit + vif->credit_bytes;
729 if (max_credit < vif->remaining_credit)
730 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
731
732 vif->remaining_credit = min(max_credit, max_burst);
733 }
734
735 static void tx_credit_callback(unsigned long data)
736 {
737 struct xenvif *vif = (struct xenvif *)data;
738 tx_add_credit(vif);
739 xenvif_check_rx_xenvif(vif);
740 }
741
742 static void xenvif_tx_err(struct xenvif *vif,
743 struct xen_netif_tx_request *txp, RING_IDX end)
744 {
745 RING_IDX cons = vif->tx.req_cons;
746
747 do {
748 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
749 if (cons == end)
750 break;
751 txp = RING_GET_REQUEST(&vif->tx, cons++);
752 } while (1);
753 vif->tx.req_cons = cons;
754 }
755
756 static void xenvif_fatal_tx_err(struct xenvif *vif)
757 {
758 netdev_err(vif->dev, "fatal error; disabling device\n");
759 xenvif_carrier_off(vif);
760 }
761
762 static int xenvif_count_requests(struct xenvif *vif,
763 struct xen_netif_tx_request *first,
764 struct xen_netif_tx_request *txp,
765 int work_to_do)
766 {
767 RING_IDX cons = vif->tx.req_cons;
768 int slots = 0;
769 int drop_err = 0;
770 int more_data;
771
772 if (!(first->flags & XEN_NETTXF_more_data))
773 return 0;
774
775 do {
776 struct xen_netif_tx_request dropped_tx = { 0 };
777
778 if (slots >= work_to_do) {
779 netdev_err(vif->dev,
780 "Asked for %d slots but exceeds this limit\n",
781 work_to_do);
782 xenvif_fatal_tx_err(vif);
783 return -ENODATA;
784 }
785
786 /* This guest is really using too many slots and
787 * considered malicious.
788 */
789 if (unlikely(slots >= fatal_skb_slots)) {
790 netdev_err(vif->dev,
791 "Malicious frontend using %d slots, threshold %u\n",
792 slots, fatal_skb_slots);
793 xenvif_fatal_tx_err(vif);
794 return -E2BIG;
795 }
796
797 /* Xen network protocol had implicit dependency on
798 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
799 * the historical MAX_SKB_FRAGS value 18 to honor the
800 * same behavior as before. Any packet using more than
801 * 18 slots but less than fatal_skb_slots slots is
802 * dropped
803 */
804 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
805 if (net_ratelimit())
806 netdev_dbg(vif->dev,
807 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
808 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
809 drop_err = -E2BIG;
810 }
811
812 if (drop_err)
813 txp = &dropped_tx;
814
815 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots),
816 sizeof(*txp));
817
818 /* If the guest submitted a frame >= 64 KiB then
819 * first->size overflowed and following slots will
820 * appear to be larger than the frame.
821 *
822 * This cannot be fatal error as there are buggy
823 * frontends that do this.
824 *
825 * Consume all slots and drop the packet.
826 */
827 if (!drop_err && txp->size > first->size) {
828 if (net_ratelimit())
829 netdev_dbg(vif->dev,
830 "Invalid tx request, slot size %u > remaining size %u\n",
831 txp->size, first->size);
832 drop_err = -EIO;
833 }
834
835 first->size -= txp->size;
836 slots++;
837
838 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
839 netdev_err(vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
840 txp->offset, txp->size);
841 xenvif_fatal_tx_err(vif);
842 return -EINVAL;
843 }
844
845 more_data = txp->flags & XEN_NETTXF_more_data;
846
847 if (!drop_err)
848 txp++;
849
850 } while (more_data);
851
852 if (drop_err) {
853 xenvif_tx_err(vif, first, cons + slots);
854 return drop_err;
855 }
856
857 return slots;
858 }
859
860 static struct page *xenvif_alloc_page(struct xenvif *vif,
861 u16 pending_idx)
862 {
863 struct page *page;
864
865 page = alloc_page(GFP_ATOMIC|__GFP_COLD);
866 if (!page)
867 return NULL;
868 vif->mmap_pages[pending_idx] = page;
869
870 return page;
871 }
872
873 static struct gnttab_copy *xenvif_get_requests(struct xenvif *vif,
874 struct sk_buff *skb,
875 struct xen_netif_tx_request *txp,
876 struct gnttab_copy *gop)
877 {
878 struct skb_shared_info *shinfo = skb_shinfo(skb);
879 skb_frag_t *frags = shinfo->frags;
880 u16 pending_idx = *((u16 *)skb->data);
881 u16 head_idx = 0;
882 int slot, start;
883 struct page *page;
884 pending_ring_idx_t index, start_idx = 0;
885 uint16_t dst_offset;
886 unsigned int nr_slots;
887 struct pending_tx_info *first = NULL;
888
889 /* At this point shinfo->nr_frags is in fact the number of
890 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
891 */
892 nr_slots = shinfo->nr_frags;
893
894 /* Skip first skb fragment if it is on same page as header fragment. */
895 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
896
897 /* Coalesce tx requests, at this point the packet passed in
898 * should be <= 64K. Any packets larger than 64K have been
899 * handled in xenvif_count_requests().
900 */
901 for (shinfo->nr_frags = slot = start; slot < nr_slots;
902 shinfo->nr_frags++) {
903 struct pending_tx_info *pending_tx_info =
904 vif->pending_tx_info;
905
906 page = alloc_page(GFP_ATOMIC|__GFP_COLD);
907 if (!page)
908 goto err;
909
910 dst_offset = 0;
911 first = NULL;
912 while (dst_offset < PAGE_SIZE && slot < nr_slots) {
913 gop->flags = GNTCOPY_source_gref;
914
915 gop->source.u.ref = txp->gref;
916 gop->source.domid = vif->domid;
917 gop->source.offset = txp->offset;
918
919 gop->dest.domid = DOMID_SELF;
920
921 gop->dest.offset = dst_offset;
922 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
923
924 if (dst_offset + txp->size > PAGE_SIZE) {
925 /* This page can only merge a portion
926 * of tx request. Do not increment any
927 * pointer / counter here. The txp
928 * will be dealt with in future
929 * rounds, eventually hitting the
930 * `else` branch.
931 */
932 gop->len = PAGE_SIZE - dst_offset;
933 txp->offset += gop->len;
934 txp->size -= gop->len;
935 dst_offset += gop->len; /* quit loop */
936 } else {
937 /* This tx request can be merged in the page */
938 gop->len = txp->size;
939 dst_offset += gop->len;
940
941 index = pending_index(vif->pending_cons++);
942
943 pending_idx = vif->pending_ring[index];
944
945 memcpy(&pending_tx_info[pending_idx].req, txp,
946 sizeof(*txp));
947
948 /* Poison these fields, corresponding
949 * fields for head tx req will be set
950 * to correct values after the loop.
951 */
952 vif->mmap_pages[pending_idx] = (void *)(~0UL);
953 pending_tx_info[pending_idx].head =
954 INVALID_PENDING_RING_IDX;
955
956 if (!first) {
957 first = &pending_tx_info[pending_idx];
958 start_idx = index;
959 head_idx = pending_idx;
960 }
961
962 txp++;
963 slot++;
964 }
965
966 gop++;
967 }
968
969 first->req.offset = 0;
970 first->req.size = dst_offset;
971 first->head = start_idx;
972 vif->mmap_pages[head_idx] = page;
973 frag_set_pending_idx(&frags[shinfo->nr_frags], head_idx);
974 }
975
976 BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);
977
978 return gop;
979 err:
980 /* Unwind, freeing all pages and sending error responses. */
981 while (shinfo->nr_frags-- > start) {
982 xenvif_idx_release(vif,
983 frag_get_pending_idx(&frags[shinfo->nr_frags]),
984 XEN_NETIF_RSP_ERROR);
985 }
986 /* The head too, if necessary. */
987 if (start)
988 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
989
990 return NULL;
991 }
992
993 static int xenvif_tx_check_gop(struct xenvif *vif,
994 struct sk_buff *skb,
995 struct gnttab_copy **gopp)
996 {
997 struct gnttab_copy *gop = *gopp;
998 u16 pending_idx = *((u16 *)skb->data);
999 struct skb_shared_info *shinfo = skb_shinfo(skb);
1000 struct pending_tx_info *tx_info;
1001 int nr_frags = shinfo->nr_frags;
1002 int i, err, start;
1003 u16 peek; /* peek into next tx request */
1004
1005 /* Check status of header. */
1006 err = gop->status;
1007 if (unlikely(err))
1008 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
1009
1010 /* Skip first skb fragment if it is on same page as header fragment. */
1011 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
1012
1013 for (i = start; i < nr_frags; i++) {
1014 int j, newerr;
1015 pending_ring_idx_t head;
1016
1017 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
1018 tx_info = &vif->pending_tx_info[pending_idx];
1019 head = tx_info->head;
1020
1021 /* Check error status: if okay then remember grant handle. */
1022 do {
1023 newerr = (++gop)->status;
1024 if (newerr)
1025 break;
1026 peek = vif->pending_ring[pending_index(++head)];
1027 } while (!pending_tx_is_head(vif, peek));
1028
1029 if (likely(!newerr)) {
1030 /* Had a previous error? Invalidate this fragment. */
1031 if (unlikely(err))
1032 xenvif_idx_release(vif, pending_idx,
1033 XEN_NETIF_RSP_OKAY);
1034 continue;
1035 }
1036
1037 /* Error on this fragment: respond to client with an error. */
1038 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
1039
1040 /* Not the first error? Preceding frags already invalidated. */
1041 if (err)
1042 continue;
1043
1044 /* First error: invalidate header and preceding fragments. */
1045 pending_idx = *((u16 *)skb->data);
1046 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
1047 for (j = start; j < i; j++) {
1048 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1049 xenvif_idx_release(vif, pending_idx,
1050 XEN_NETIF_RSP_OKAY);
1051 }
1052
1053 /* Remember the error: invalidate all subsequent fragments. */
1054 err = newerr;
1055 }
1056
1057 *gopp = gop + 1;
1058 return err;
1059 }
1060
1061 static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
1062 {
1063 struct skb_shared_info *shinfo = skb_shinfo(skb);
1064 int nr_frags = shinfo->nr_frags;
1065 int i;
1066
1067 for (i = 0; i < nr_frags; i++) {
1068 skb_frag_t *frag = shinfo->frags + i;
1069 struct xen_netif_tx_request *txp;
1070 struct page *page;
1071 u16 pending_idx;
1072
1073 pending_idx = frag_get_pending_idx(frag);
1074
1075 txp = &vif->pending_tx_info[pending_idx].req;
1076 page = virt_to_page(idx_to_kaddr(vif, pending_idx));
1077 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1078 skb->len += txp->size;
1079 skb->data_len += txp->size;
1080 skb->truesize += txp->size;
1081
1082 /* Take an extra reference to offset xenvif_idx_release */
1083 get_page(vif->mmap_pages[pending_idx]);
1084 xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
1085 }
1086 }
1087
1088 static int xenvif_get_extras(struct xenvif *vif,
1089 struct xen_netif_extra_info *extras,
1090 int work_to_do)
1091 {
1092 struct xen_netif_extra_info extra;
1093 RING_IDX cons = vif->tx.req_cons;
1094
1095 do {
1096 if (unlikely(work_to_do-- <= 0)) {
1097 netdev_err(vif->dev, "Missing extra info\n");
1098 xenvif_fatal_tx_err(vif);
1099 return -EBADR;
1100 }
1101
1102 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1103 sizeof(extra));
1104 if (unlikely(!extra.type ||
1105 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1106 vif->tx.req_cons = ++cons;
1107 netdev_err(vif->dev,
1108 "Invalid extra type: %d\n", extra.type);
1109 xenvif_fatal_tx_err(vif);
1110 return -EINVAL;
1111 }
1112
1113 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1114 vif->tx.req_cons = ++cons;
1115 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1116
1117 return work_to_do;
1118 }
1119
1120 static int xenvif_set_skb_gso(struct xenvif *vif,
1121 struct sk_buff *skb,
1122 struct xen_netif_extra_info *gso)
1123 {
1124 if (!gso->u.gso.size) {
1125 netdev_err(vif->dev, "GSO size must not be zero.\n");
1126 xenvif_fatal_tx_err(vif);
1127 return -EINVAL;
1128 }
1129
1130 switch (gso->u.gso.type) {
1131 case XEN_NETIF_GSO_TYPE_TCPV4:
1132 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1133 break;
1134 case XEN_NETIF_GSO_TYPE_TCPV6:
1135 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1136 break;
1137 default:
1138 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1139 xenvif_fatal_tx_err(vif);
1140 return -EINVAL;
1141 }
1142
1143 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1144
1145 /* Header must be checked, and gso_segs computed. */
1146 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1147 skb_shinfo(skb)->gso_segs = 0;
1148
1149 return 0;
1150 }
1151
1152 static inline void maybe_pull_tail(struct sk_buff *skb, unsigned int len)
1153 {
1154 if (skb_is_nonlinear(skb) && skb_headlen(skb) < len) {
1155 /* If we need to pullup then pullup to the max, so we
1156 * won't need to do it again.
1157 */
1158 int target = min_t(int, skb->len, MAX_TCP_HEADER);
1159 __pskb_pull_tail(skb, target - skb_headlen(skb));
1160 }
1161 }
1162
1163 static int checksum_setup_ip(struct xenvif *vif, struct sk_buff *skb,
1164 int recalculate_partial_csum)
1165 {
1166 struct iphdr *iph = (void *)skb->data;
1167 unsigned int header_size;
1168 unsigned int off;
1169 int err = -EPROTO;
1170
1171 off = sizeof(struct iphdr);
1172
1173 header_size = skb->network_header + off + MAX_IPOPTLEN;
1174 maybe_pull_tail(skb, header_size);
1175
1176 off = iph->ihl * 4;
1177
1178 switch (iph->protocol) {
1179 case IPPROTO_TCP:
1180 if (!skb_partial_csum_set(skb, off,
1181 offsetof(struct tcphdr, check)))
1182 goto out;
1183
1184 if (recalculate_partial_csum) {
1185 struct tcphdr *tcph = tcp_hdr(skb);
1186
1187 header_size = skb->network_header +
1188 off +
1189 sizeof(struct tcphdr);
1190 maybe_pull_tail(skb, header_size);
1191
1192 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1193 skb->len - off,
1194 IPPROTO_TCP, 0);
1195 }
1196 break;
1197 case IPPROTO_UDP:
1198 if (!skb_partial_csum_set(skb, off,
1199 offsetof(struct udphdr, check)))
1200 goto out;
1201
1202 if (recalculate_partial_csum) {
1203 struct udphdr *udph = udp_hdr(skb);
1204
1205 header_size = skb->network_header +
1206 off +
1207 sizeof(struct udphdr);
1208 maybe_pull_tail(skb, header_size);
1209
1210 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1211 skb->len - off,
1212 IPPROTO_UDP, 0);
1213 }
1214 break;
1215 default:
1216 if (net_ratelimit())
1217 netdev_err(vif->dev,
1218 "Attempting to checksum a non-TCP/UDP packet, "
1219 "dropping a protocol %d packet\n",
1220 iph->protocol);
1221 goto out;
1222 }
1223
1224 err = 0;
1225
1226 out:
1227 return err;
1228 }
1229
1230 static int checksum_setup_ipv6(struct xenvif *vif, struct sk_buff *skb,
1231 int recalculate_partial_csum)
1232 {
1233 int err = -EPROTO;
1234 struct ipv6hdr *ipv6h = (void *)skb->data;
1235 u8 nexthdr;
1236 unsigned int header_size;
1237 unsigned int off;
1238 bool fragment;
1239 bool done;
1240
1241 done = false;
1242
1243 off = sizeof(struct ipv6hdr);
1244
1245 header_size = skb->network_header + off;
1246 maybe_pull_tail(skb, header_size);
1247
1248 nexthdr = ipv6h->nexthdr;
1249
1250 while ((off <= sizeof(struct ipv6hdr) + ntohs(ipv6h->payload_len)) &&
1251 !done) {
1252 switch (nexthdr) {
1253 case IPPROTO_DSTOPTS:
1254 case IPPROTO_HOPOPTS:
1255 case IPPROTO_ROUTING: {
1256 struct ipv6_opt_hdr *hp = (void *)(skb->data + off);
1257
1258 header_size = skb->network_header +
1259 off +
1260 sizeof(struct ipv6_opt_hdr);
1261 maybe_pull_tail(skb, header_size);
1262
1263 nexthdr = hp->nexthdr;
1264 off += ipv6_optlen(hp);
1265 break;
1266 }
1267 case IPPROTO_AH: {
1268 struct ip_auth_hdr *hp = (void *)(skb->data + off);
1269
1270 header_size = skb->network_header +
1271 off +
1272 sizeof(struct ip_auth_hdr);
1273 maybe_pull_tail(skb, header_size);
1274
1275 nexthdr = hp->nexthdr;
1276 off += (hp->hdrlen+2)<<2;
1277 break;
1278 }
1279 case IPPROTO_FRAGMENT:
1280 fragment = true;
1281 /* fall through */
1282 default:
1283 done = true;
1284 break;
1285 }
1286 }
1287
1288 if (!done) {
1289 if (net_ratelimit())
1290 netdev_err(vif->dev, "Failed to parse packet header\n");
1291 goto out;
1292 }
1293
1294 if (fragment) {
1295 if (net_ratelimit())
1296 netdev_err(vif->dev, "Packet is a fragment!\n");
1297 goto out;
1298 }
1299
1300 switch (nexthdr) {
1301 case IPPROTO_TCP:
1302 if (!skb_partial_csum_set(skb, off,
1303 offsetof(struct tcphdr, check)))
1304 goto out;
1305
1306 if (recalculate_partial_csum) {
1307 struct tcphdr *tcph = tcp_hdr(skb);
1308
1309 header_size = skb->network_header +
1310 off +
1311 sizeof(struct tcphdr);
1312 maybe_pull_tail(skb, header_size);
1313
1314 tcph->check = ~csum_ipv6_magic(&ipv6h->saddr,
1315 &ipv6h->daddr,
1316 skb->len - off,
1317 IPPROTO_TCP, 0);
1318 }
1319 break;
1320 case IPPROTO_UDP:
1321 if (!skb_partial_csum_set(skb, off,
1322 offsetof(struct udphdr, check)))
1323 goto out;
1324
1325 if (recalculate_partial_csum) {
1326 struct udphdr *udph = udp_hdr(skb);
1327
1328 header_size = skb->network_header +
1329 off +
1330 sizeof(struct udphdr);
1331 maybe_pull_tail(skb, header_size);
1332
1333 udph->check = ~csum_ipv6_magic(&ipv6h->saddr,
1334 &ipv6h->daddr,
1335 skb->len - off,
1336 IPPROTO_UDP, 0);
1337 }
1338 break;
1339 default:
1340 if (net_ratelimit())
1341 netdev_err(vif->dev,
1342 "Attempting to checksum a non-TCP/UDP packet, "
1343 "dropping a protocol %d packet\n",
1344 nexthdr);
1345 goto out;
1346 }
1347
1348 err = 0;
1349
1350 out:
1351 return err;
1352 }
1353
1354 static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1355 {
1356 int err = -EPROTO;
1357 int recalculate_partial_csum = 0;
1358
1359 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1360 * peers can fail to set NETRXF_csum_blank when sending a GSO
1361 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1362 * recalculate the partial checksum.
1363 */
1364 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1365 vif->rx_gso_checksum_fixup++;
1366 skb->ip_summed = CHECKSUM_PARTIAL;
1367 recalculate_partial_csum = 1;
1368 }
1369
1370 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1371 if (skb->ip_summed != CHECKSUM_PARTIAL)
1372 return 0;
1373
1374 if (skb->protocol == htons(ETH_P_IP))
1375 err = checksum_setup_ip(vif, skb, recalculate_partial_csum);
1376 else if (skb->protocol == htons(ETH_P_IPV6))
1377 err = checksum_setup_ipv6(vif, skb, recalculate_partial_csum);
1378
1379 return err;
1380 }
1381
1382 static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1383 {
1384 u64 now = get_jiffies_64();
1385 u64 next_credit = vif->credit_window_start +
1386 msecs_to_jiffies(vif->credit_usec / 1000);
1387
1388 /* Timer could already be pending in rare cases. */
1389 if (timer_pending(&vif->credit_timeout))
1390 return true;
1391
1392 /* Passed the point where we can replenish credit? */
1393 if (time_after_eq64(now, next_credit)) {
1394 vif->credit_window_start = now;
1395 tx_add_credit(vif);
1396 }
1397
1398 /* Still too big to send right now? Set a callback. */
1399 if (size > vif->remaining_credit) {
1400 vif->credit_timeout.data =
1401 (unsigned long)vif;
1402 vif->credit_timeout.function =
1403 tx_credit_callback;
1404 mod_timer(&vif->credit_timeout,
1405 next_credit);
1406 vif->credit_window_start = next_credit;
1407
1408 return true;
1409 }
1410
1411 return false;
1412 }
1413
1414 static unsigned xenvif_tx_build_gops(struct xenvif *vif)
1415 {
1416 struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop;
1417 struct sk_buff *skb;
1418 int ret;
1419
1420 while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
1421 < MAX_PENDING_REQS)) {
1422 struct xen_netif_tx_request txreq;
1423 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1424 struct page *page;
1425 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1426 u16 pending_idx;
1427 RING_IDX idx;
1428 int work_to_do;
1429 unsigned int data_len;
1430 pending_ring_idx_t index;
1431
1432 if (vif->tx.sring->req_prod - vif->tx.req_cons >
1433 XEN_NETIF_TX_RING_SIZE) {
1434 netdev_err(vif->dev,
1435 "Impossible number of requests. "
1436 "req_prod %d, req_cons %d, size %ld\n",
1437 vif->tx.sring->req_prod, vif->tx.req_cons,
1438 XEN_NETIF_TX_RING_SIZE);
1439 xenvif_fatal_tx_err(vif);
1440 continue;
1441 }
1442
1443 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1444 if (!work_to_do)
1445 break;
1446
1447 idx = vif->tx.req_cons;
1448 rmb(); /* Ensure that we see the request before we copy it. */
1449 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1450
1451 /* Credit-based scheduling. */
1452 if (txreq.size > vif->remaining_credit &&
1453 tx_credit_exceeded(vif, txreq.size))
1454 break;
1455
1456 vif->remaining_credit -= txreq.size;
1457
1458 work_to_do--;
1459 vif->tx.req_cons = ++idx;
1460
1461 memset(extras, 0, sizeof(extras));
1462 if (txreq.flags & XEN_NETTXF_extra_info) {
1463 work_to_do = xenvif_get_extras(vif, extras,
1464 work_to_do);
1465 idx = vif->tx.req_cons;
1466 if (unlikely(work_to_do < 0))
1467 break;
1468 }
1469
1470 ret = xenvif_count_requests(vif, &txreq, txfrags, work_to_do);
1471 if (unlikely(ret < 0))
1472 break;
1473
1474 idx += ret;
1475
1476 if (unlikely(txreq.size < ETH_HLEN)) {
1477 netdev_dbg(vif->dev,
1478 "Bad packet size: %d\n", txreq.size);
1479 xenvif_tx_err(vif, &txreq, idx);
1480 break;
1481 }
1482
1483 /* No crossing a page as the payload mustn't fragment. */
1484 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1485 netdev_err(vif->dev,
1486 "txreq.offset: %x, size: %u, end: %lu\n",
1487 txreq.offset, txreq.size,
1488 (txreq.offset&~PAGE_MASK) + txreq.size);
1489 xenvif_fatal_tx_err(vif);
1490 break;
1491 }
1492
1493 index = pending_index(vif->pending_cons);
1494 pending_idx = vif->pending_ring[index];
1495
1496 data_len = (txreq.size > PKT_PROT_LEN &&
1497 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1498 PKT_PROT_LEN : txreq.size;
1499
1500 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1501 GFP_ATOMIC | __GFP_NOWARN);
1502 if (unlikely(skb == NULL)) {
1503 netdev_dbg(vif->dev,
1504 "Can't allocate a skb in start_xmit.\n");
1505 xenvif_tx_err(vif, &txreq, idx);
1506 break;
1507 }
1508
1509 /* Packets passed to netif_rx() must have some headroom. */
1510 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1511
1512 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1513 struct xen_netif_extra_info *gso;
1514 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1515
1516 if (xenvif_set_skb_gso(vif, skb, gso)) {
1517 /* Failure in xenvif_set_skb_gso is fatal. */
1518 kfree_skb(skb);
1519 break;
1520 }
1521 }
1522
1523 /* XXX could copy straight to head */
1524 page = xenvif_alloc_page(vif, pending_idx);
1525 if (!page) {
1526 kfree_skb(skb);
1527 xenvif_tx_err(vif, &txreq, idx);
1528 break;
1529 }
1530
1531 gop->source.u.ref = txreq.gref;
1532 gop->source.domid = vif->domid;
1533 gop->source.offset = txreq.offset;
1534
1535 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1536 gop->dest.domid = DOMID_SELF;
1537 gop->dest.offset = txreq.offset;
1538
1539 gop->len = txreq.size;
1540 gop->flags = GNTCOPY_source_gref;
1541
1542 gop++;
1543
1544 memcpy(&vif->pending_tx_info[pending_idx].req,
1545 &txreq, sizeof(txreq));
1546 vif->pending_tx_info[pending_idx].head = index;
1547 *((u16 *)skb->data) = pending_idx;
1548
1549 __skb_put(skb, data_len);
1550
1551 skb_shinfo(skb)->nr_frags = ret;
1552 if (data_len < txreq.size) {
1553 skb_shinfo(skb)->nr_frags++;
1554 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1555 pending_idx);
1556 } else {
1557 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1558 INVALID_PENDING_IDX);
1559 }
1560
1561 vif->pending_cons++;
1562
1563 request_gop = xenvif_get_requests(vif, skb, txfrags, gop);
1564 if (request_gop == NULL) {
1565 kfree_skb(skb);
1566 xenvif_tx_err(vif, &txreq, idx);
1567 break;
1568 }
1569 gop = request_gop;
1570
1571 __skb_queue_tail(&vif->tx_queue, skb);
1572
1573 vif->tx.req_cons = idx;
1574
1575 if ((gop-vif->tx_copy_ops) >= ARRAY_SIZE(vif->tx_copy_ops))
1576 break;
1577 }
1578
1579 return gop - vif->tx_copy_ops;
1580 }
1581
1582
1583 static int xenvif_tx_submit(struct xenvif *vif, int budget)
1584 {
1585 struct gnttab_copy *gop = vif->tx_copy_ops;
1586 struct sk_buff *skb;
1587 int work_done = 0;
1588
1589 while (work_done < budget &&
1590 (skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
1591 struct xen_netif_tx_request *txp;
1592 u16 pending_idx;
1593 unsigned data_len;
1594
1595 pending_idx = *((u16 *)skb->data);
1596 txp = &vif->pending_tx_info[pending_idx].req;
1597
1598 /* Check the remap error code. */
1599 if (unlikely(xenvif_tx_check_gop(vif, skb, &gop))) {
1600 netdev_dbg(vif->dev, "netback grant failed.\n");
1601 skb_shinfo(skb)->nr_frags = 0;
1602 kfree_skb(skb);
1603 continue;
1604 }
1605
1606 data_len = skb->len;
1607 memcpy(skb->data,
1608 (void *)(idx_to_kaddr(vif, pending_idx)|txp->offset),
1609 data_len);
1610 if (data_len < txp->size) {
1611 /* Append the packet payload as a fragment. */
1612 txp->offset += data_len;
1613 txp->size -= data_len;
1614 } else {
1615 /* Schedule a response immediately. */
1616 xenvif_idx_release(vif, pending_idx,
1617 XEN_NETIF_RSP_OKAY);
1618 }
1619
1620 if (txp->flags & XEN_NETTXF_csum_blank)
1621 skb->ip_summed = CHECKSUM_PARTIAL;
1622 else if (txp->flags & XEN_NETTXF_data_validated)
1623 skb->ip_summed = CHECKSUM_UNNECESSARY;
1624
1625 xenvif_fill_frags(vif, skb);
1626
1627 if (skb_is_nonlinear(skb) && skb_headlen(skb) < PKT_PROT_LEN) {
1628 int target = min_t(int, skb->len, PKT_PROT_LEN);
1629 __pskb_pull_tail(skb, target - skb_headlen(skb));
1630 }
1631
1632 skb->dev = vif->dev;
1633 skb->protocol = eth_type_trans(skb, skb->dev);
1634 skb_reset_network_header(skb);
1635
1636 if (checksum_setup(vif, skb)) {
1637 netdev_dbg(vif->dev,
1638 "Can't setup checksum in net_tx_action\n");
1639 kfree_skb(skb);
1640 continue;
1641 }
1642
1643 skb_probe_transport_header(skb, 0);
1644
1645 vif->dev->stats.rx_bytes += skb->len;
1646 vif->dev->stats.rx_packets++;
1647
1648 work_done++;
1649
1650 netif_receive_skb(skb);
1651 }
1652
1653 return work_done;
1654 }
1655
1656 /* Called after netfront has transmitted */
1657 int xenvif_tx_action(struct xenvif *vif, int budget)
1658 {
1659 unsigned nr_gops;
1660 int work_done;
1661
1662 if (unlikely(!tx_work_todo(vif)))
1663 return 0;
1664
1665 nr_gops = xenvif_tx_build_gops(vif);
1666
1667 if (nr_gops == 0)
1668 return 0;
1669
1670 gnttab_batch_copy(vif->tx_copy_ops, nr_gops);
1671
1672 work_done = xenvif_tx_submit(vif, nr_gops);
1673
1674 return work_done;
1675 }
1676
1677 static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
1678 u8 status)
1679 {
1680 struct pending_tx_info *pending_tx_info;
1681 pending_ring_idx_t head;
1682 u16 peek; /* peek into next tx request */
1683
1684 BUG_ON(vif->mmap_pages[pending_idx] == (void *)(~0UL));
1685
1686 /* Already complete? */
1687 if (vif->mmap_pages[pending_idx] == NULL)
1688 return;
1689
1690 pending_tx_info = &vif->pending_tx_info[pending_idx];
1691
1692 head = pending_tx_info->head;
1693
1694 BUG_ON(!pending_tx_is_head(vif, head));
1695 BUG_ON(vif->pending_ring[pending_index(head)] != pending_idx);
1696
1697 do {
1698 pending_ring_idx_t index;
1699 pending_ring_idx_t idx = pending_index(head);
1700 u16 info_idx = vif->pending_ring[idx];
1701
1702 pending_tx_info = &vif->pending_tx_info[info_idx];
1703 make_tx_response(vif, &pending_tx_info->req, status);
1704
1705 /* Setting any number other than
1706 * INVALID_PENDING_RING_IDX indicates this slot is
1707 * starting a new packet / ending a previous packet.
1708 */
1709 pending_tx_info->head = 0;
1710
1711 index = pending_index(vif->pending_prod++);
1712 vif->pending_ring[index] = vif->pending_ring[info_idx];
1713
1714 peek = vif->pending_ring[pending_index(++head)];
1715
1716 } while (!pending_tx_is_head(vif, peek));
1717
1718 put_page(vif->mmap_pages[pending_idx]);
1719 vif->mmap_pages[pending_idx] = NULL;
1720 }
1721
1722
1723 static void make_tx_response(struct xenvif *vif,
1724 struct xen_netif_tx_request *txp,
1725 s8 st)
1726 {
1727 RING_IDX i = vif->tx.rsp_prod_pvt;
1728 struct xen_netif_tx_response *resp;
1729 int notify;
1730
1731 resp = RING_GET_RESPONSE(&vif->tx, i);
1732 resp->id = txp->id;
1733 resp->status = st;
1734
1735 if (txp->flags & XEN_NETTXF_extra_info)
1736 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1737
1738 vif->tx.rsp_prod_pvt = ++i;
1739 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1740 if (notify)
1741 notify_remote_via_irq(vif->tx_irq);
1742 }
1743
1744 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1745 u16 id,
1746 s8 st,
1747 u16 offset,
1748 u16 size,
1749 u16 flags)
1750 {
1751 RING_IDX i = vif->rx.rsp_prod_pvt;
1752 struct xen_netif_rx_response *resp;
1753
1754 resp = RING_GET_RESPONSE(&vif->rx, i);
1755 resp->offset = offset;
1756 resp->flags = flags;
1757 resp->id = id;
1758 resp->status = (s16)size;
1759 if (st < 0)
1760 resp->status = (s16)st;
1761
1762 vif->rx.rsp_prod_pvt = ++i;
1763
1764 return resp;
1765 }
1766
1767 static inline int rx_work_todo(struct xenvif *vif)
1768 {
1769 return !skb_queue_empty(&vif->rx_queue);
1770 }
1771
1772 static inline int tx_work_todo(struct xenvif *vif)
1773 {
1774
1775 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)) &&
1776 (nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
1777 < MAX_PENDING_REQS))
1778 return 1;
1779
1780 return 0;
1781 }
1782
1783 void xenvif_unmap_frontend_rings(struct xenvif *vif)
1784 {
1785 if (vif->tx.sring)
1786 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1787 vif->tx.sring);
1788 if (vif->rx.sring)
1789 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1790 vif->rx.sring);
1791 }
1792
1793 int xenvif_map_frontend_rings(struct xenvif *vif,
1794 grant_ref_t tx_ring_ref,
1795 grant_ref_t rx_ring_ref)
1796 {
1797 void *addr;
1798 struct xen_netif_tx_sring *txs;
1799 struct xen_netif_rx_sring *rxs;
1800
1801 int err = -ENOMEM;
1802
1803 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1804 tx_ring_ref, &addr);
1805 if (err)
1806 goto err;
1807
1808 txs = (struct xen_netif_tx_sring *)addr;
1809 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1810
1811 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1812 rx_ring_ref, &addr);
1813 if (err)
1814 goto err;
1815
1816 rxs = (struct xen_netif_rx_sring *)addr;
1817 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1818
1819 vif->rx_req_cons_peek = 0;
1820
1821 return 0;
1822
1823 err:
1824 xenvif_unmap_frontend_rings(vif);
1825 return err;
1826 }
1827
1828 int xenvif_kthread(void *data)
1829 {
1830 struct xenvif *vif = data;
1831
1832 while (!kthread_should_stop()) {
1833 wait_event_interruptible(vif->wq,
1834 rx_work_todo(vif) ||
1835 kthread_should_stop());
1836 if (kthread_should_stop())
1837 break;
1838
1839 if (rx_work_todo(vif))
1840 xenvif_rx_action(vif);
1841
1842 cond_resched();
1843 }
1844
1845 return 0;
1846 }
1847
1848 static int __init netback_init(void)
1849 {
1850 int rc = 0;
1851
1852 if (!xen_domain())
1853 return -ENODEV;
1854
1855 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1856 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1857 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1858 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1859 }
1860
1861 rc = xenvif_xenbus_init();
1862 if (rc)
1863 goto failed_init;
1864
1865 return 0;
1866
1867 failed_init:
1868 return rc;
1869 }
1870
1871 module_init(netback_init);
1872
1873 static void __exit netback_fini(void)
1874 {
1875 xenvif_xenbus_fini();
1876 }
1877 module_exit(netback_fini);
1878
1879 MODULE_LICENSE("Dual BSD/GPL");
1880 MODULE_ALIAS("xen-backend:vif");
Linux kernel - Deliverables
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