1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * xfrm_device.c - IPsec device offloading code.
4 *
5 * Copyright (c) 2015 secunet Security Networks AG
6 *
7 * Author:
8 * Steffen Klassert <steffen.klassert@secunet.com>
9 */
10
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/netdevice.h>
14 #include <linux/skbuff.h>
15 #include <linux/slab.h>
16 #include <linux/spinlock.h>
17 #include <net/dst.h>
18 #include <net/gso.h>
19 #include <net/xfrm.h>
20 #include <linux/notifier.h>
21
22 #ifdef CONFIG_XFRM_OFFLOAD
__xfrm_transport_prep(struct xfrm_state * x,struct sk_buff * skb,unsigned int hsize)23 static void __xfrm_transport_prep(struct xfrm_state *x, struct sk_buff *skb,
24 unsigned int hsize)
25 {
26 struct xfrm_offload *xo = xfrm_offload(skb);
27
28 skb_reset_mac_len(skb);
29 if (xo->flags & XFRM_GSO_SEGMENT)
30 skb->transport_header -= x->props.header_len;
31
32 pskb_pull(skb, skb_transport_offset(skb) + x->props.header_len);
33 }
34
__xfrm_mode_tunnel_prep(struct xfrm_state * x,struct sk_buff * skb,unsigned int hsize)35 static void __xfrm_mode_tunnel_prep(struct xfrm_state *x, struct sk_buff *skb,
36 unsigned int hsize)
37
38 {
39 struct xfrm_offload *xo = xfrm_offload(skb);
40
41 if (xo->flags & XFRM_GSO_SEGMENT)
42 skb->transport_header = skb->network_header + hsize;
43
44 skb_reset_mac_len(skb);
45 pskb_pull(skb,
46 skb->mac_len + x->props.header_len - x->props.enc_hdr_len);
47 }
48
__xfrm_mode_beet_prep(struct xfrm_state * x,struct sk_buff * skb,unsigned int hsize)49 static void __xfrm_mode_beet_prep(struct xfrm_state *x, struct sk_buff *skb,
50 unsigned int hsize)
51 {
52 struct xfrm_offload *xo = xfrm_offload(skb);
53 int phlen = 0;
54
55 if (xo->flags & XFRM_GSO_SEGMENT)
56 skb->transport_header = skb->network_header + hsize;
57
58 skb_reset_mac_len(skb);
59 if (x->sel.family != AF_INET6) {
60 phlen = IPV4_BEET_PHMAXLEN;
61 if (x->outer_mode.family == AF_INET6)
62 phlen += sizeof(struct ipv6hdr) - sizeof(struct iphdr);
63 }
64
65 pskb_pull(skb, skb->mac_len + hsize + (x->props.header_len - phlen));
66 }
67
68 /* Adjust pointers into the packet when IPsec is done at layer2 */
xfrm_outer_mode_prep(struct xfrm_state * x,struct sk_buff * skb)69 static void xfrm_outer_mode_prep(struct xfrm_state *x, struct sk_buff *skb)
70 {
71 switch (x->outer_mode.encap) {
72 case XFRM_MODE_IPTFS:
73 case XFRM_MODE_TUNNEL:
74 if (x->outer_mode.family == AF_INET)
75 return __xfrm_mode_tunnel_prep(x, skb,
76 sizeof(struct iphdr));
77 if (x->outer_mode.family == AF_INET6)
78 return __xfrm_mode_tunnel_prep(x, skb,
79 sizeof(struct ipv6hdr));
80 break;
81 case XFRM_MODE_TRANSPORT:
82 if (x->outer_mode.family == AF_INET)
83 return __xfrm_transport_prep(x, skb,
84 sizeof(struct iphdr));
85 if (x->outer_mode.family == AF_INET6)
86 return __xfrm_transport_prep(x, skb,
87 sizeof(struct ipv6hdr));
88 break;
89 case XFRM_MODE_BEET:
90 if (x->outer_mode.family == AF_INET)
91 return __xfrm_mode_beet_prep(x, skb,
92 sizeof(struct iphdr));
93 if (x->outer_mode.family == AF_INET6)
94 return __xfrm_mode_beet_prep(x, skb,
95 sizeof(struct ipv6hdr));
96 break;
97 case XFRM_MODE_ROUTEOPTIMIZATION:
98 case XFRM_MODE_IN_TRIGGER:
99 break;
100 }
101 }
102
xmit_xfrm_check_overflow(struct sk_buff * skb)103 static inline bool xmit_xfrm_check_overflow(struct sk_buff *skb)
104 {
105 struct xfrm_offload *xo = xfrm_offload(skb);
106 __u32 seq = xo->seq.low;
107
108 seq += skb_shinfo(skb)->gso_segs;
109 if (unlikely(seq < xo->seq.low))
110 return true;
111
112 return false;
113 }
114
validate_xmit_xfrm(struct sk_buff * skb,netdev_features_t features,bool * again)115 struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features, bool *again)
116 {
117 int err;
118 unsigned long flags;
119 struct xfrm_state *x;
120 struct softnet_data *sd;
121 struct sk_buff *skb2, *nskb, *pskb = NULL;
122 netdev_features_t esp_features = features;
123 struct xfrm_offload *xo = xfrm_offload(skb);
124 struct net_device *dev = skb->dev;
125 struct sec_path *sp;
126
127 if (!xo || (xo->flags & XFRM_XMIT))
128 return skb;
129
130 if (!(features & NETIF_F_HW_ESP))
131 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
132
133 sp = skb_sec_path(skb);
134 x = sp->xvec[sp->len - 1];
135 if (xo->flags & XFRM_GRO || x->xso.dir == XFRM_DEV_OFFLOAD_IN)
136 return skb;
137
138 /* The packet was sent to HW IPsec packet offload engine,
139 * but to wrong device. Drop the packet, so it won't skip
140 * XFRM stack.
141 */
142 if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET && x->xso.dev != dev) {
143 kfree_skb(skb);
144 dev_core_stats_tx_dropped_inc(dev);
145 return NULL;
146 }
147
148 local_irq_save(flags);
149 sd = this_cpu_ptr(&softnet_data);
150 err = !skb_queue_empty(&sd->xfrm_backlog);
151 local_irq_restore(flags);
152
153 if (err) {
154 *again = true;
155 return skb;
156 }
157
158 if (skb_is_gso(skb) && (unlikely(x->xso.dev != dev) ||
159 unlikely(xmit_xfrm_check_overflow(skb)))) {
160 struct sk_buff *segs;
161
162 /* Packet got rerouted, fixup features and segment it. */
163 esp_features = esp_features & ~(NETIF_F_HW_ESP | NETIF_F_GSO_ESP);
164
165 segs = skb_gso_segment(skb, esp_features);
166 if (IS_ERR(segs)) {
167 kfree_skb(skb);
168 dev_core_stats_tx_dropped_inc(dev);
169 return NULL;
170 } else {
171 consume_skb(skb);
172 skb = segs;
173 }
174 }
175
176 if (!skb->next) {
177 esp_features |= skb->dev->gso_partial_features;
178 xfrm_outer_mode_prep(x, skb);
179
180 xo->flags |= XFRM_DEV_RESUME;
181
182 err = x->type_offload->xmit(x, skb, esp_features);
183 if (err) {
184 if (err == -EINPROGRESS)
185 return ERR_PTR(-EINPROGRESS);
186
187 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
188 kfree_skb(skb);
189 return NULL;
190 }
191
192 skb_push(skb, skb->data - skb_mac_header(skb));
193
194 return skb;
195 }
196
197 skb_list_walk_safe(skb, skb2, nskb) {
198 esp_features |= skb->dev->gso_partial_features;
199 skb_mark_not_on_list(skb2);
200
201 xo = xfrm_offload(skb2);
202 xo->flags |= XFRM_DEV_RESUME;
203
204 xfrm_outer_mode_prep(x, skb2);
205
206 err = x->type_offload->xmit(x, skb2, esp_features);
207 if (!err) {
208 skb2->next = nskb;
209 } else if (err != -EINPROGRESS) {
210 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
211 skb2->next = nskb;
212 kfree_skb_list(skb2);
213 return NULL;
214 } else {
215 if (skb == skb2)
216 skb = nskb;
217 else
218 pskb->next = nskb;
219
220 continue;
221 }
222
223 skb_push(skb2, skb2->data - skb_mac_header(skb2));
224 pskb = skb2;
225 }
226
227 /* skb_gso_segment() set skb->prev to the last segment, but async
228 * crypto may have stolen it above without updating ->prev. Repoint
229 * it at the last retained segment so validate_xmit_skb_list() does
230 * not chain onto a segment now owned by the crypto engine.
231 */
232 if (skb)
233 skb->prev = pskb;
234
235 return skb ? skb : ERR_PTR(-EINPROGRESS);
236 }
237 EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
238
xfrm_dev_state_add(struct net * net,struct xfrm_state * x,const struct xfrm_user_offload * xuo,struct netlink_ext_ack * extack)239 int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
240 const struct xfrm_user_offload *xuo,
241 struct netlink_ext_ack *extack)
242 {
243 int err;
244 struct dst_entry *dst;
245 struct net_device *dev;
246 struct xfrm_dev_offload *xso = &x->xso;
247 xfrm_address_t *saddr;
248 xfrm_address_t *daddr;
249 bool is_packet_offload;
250
251 if (xuo->flags &
252 ~(XFRM_OFFLOAD_IPV6 | XFRM_OFFLOAD_INBOUND | XFRM_OFFLOAD_PACKET)) {
253 NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
254 return -EINVAL;
255 }
256
257 if ((xuo->flags & XFRM_OFFLOAD_INBOUND && x->dir == XFRM_SA_DIR_OUT) ||
258 (!(xuo->flags & XFRM_OFFLOAD_INBOUND) && x->dir == XFRM_SA_DIR_IN)) {
259 NL_SET_ERR_MSG(extack, "Mismatched SA and offload direction");
260 return -EINVAL;
261 }
262
263 if (xuo->flags & XFRM_OFFLOAD_INBOUND && x->if_id) {
264 NL_SET_ERR_MSG(extack, "XFRM if_id is not supported in RX path");
265 return -EINVAL;
266 }
267
268 is_packet_offload = xuo->flags & XFRM_OFFLOAD_PACKET;
269
270 /* We don't yet support TFC padding. */
271 if (x->tfcpad) {
272 NL_SET_ERR_MSG(extack, "TFC padding can't be offloaded");
273 return -EINVAL;
274 }
275
276 dev = dev_get_by_index(net, xuo->ifindex);
277 if (!dev) {
278 struct xfrm_dst_lookup_params params;
279
280 if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
281 saddr = &x->props.saddr;
282 daddr = &x->id.daddr;
283 } else {
284 saddr = &x->id.daddr;
285 daddr = &x->props.saddr;
286 }
287
288 memset(¶ms, 0, sizeof(params));
289 params.net = net;
290 params.saddr = saddr;
291 params.daddr = daddr;
292 params.mark = xfrm_smark_get(0, x);
293 dst = __xfrm_dst_lookup(x->props.family, ¶ms);
294 if (IS_ERR(dst))
295 return (is_packet_offload) ? -EINVAL : 0;
296
297 dev = dst->dev;
298
299 dev_hold(dev);
300 dst_release(dst);
301 }
302
303 if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
304 xso->dev = NULL;
305 dev_put(dev);
306 return (is_packet_offload) ? -EINVAL : 0;
307 }
308
309 if (!is_packet_offload && x->props.flags & XFRM_STATE_ESN &&
310 !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
311 NL_SET_ERR_MSG(extack, "Device doesn't support offload with ESN");
312 xso->dev = NULL;
313 dev_put(dev);
314 return -EINVAL;
315 }
316
317 if (!x->type_offload) {
318 NL_SET_ERR_MSG(extack, "Type doesn't support offload");
319 dev_put(dev);
320 return -EINVAL;
321 }
322
323 xso->dev = dev;
324 xso->ifindex = dev->ifindex;
325 netdev_tracker_alloc(dev, &xso->dev_tracker, GFP_ATOMIC);
326
327 if (xuo->flags & XFRM_OFFLOAD_INBOUND)
328 xso->dir = XFRM_DEV_OFFLOAD_IN;
329 else
330 xso->dir = XFRM_DEV_OFFLOAD_OUT;
331
332 if (is_packet_offload)
333 xso->type = XFRM_DEV_OFFLOAD_PACKET;
334 else
335 xso->type = XFRM_DEV_OFFLOAD_CRYPTO;
336
337 err = dev->xfrmdev_ops->xdo_dev_state_add(dev, x, extack);
338 if (err) {
339 xso->dev = NULL;
340 xso->dir = 0;
341 netdev_put(dev, &xso->dev_tracker);
342 xso->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
343
344 xfrm_unset_type_offload(x);
345 /* User explicitly requested packet offload mode and configured
346 * policy in addition to the XFRM state. So be civil to users,
347 * and return an error instead of taking fallback path.
348 */
349 if ((err != -EOPNOTSUPP && !is_packet_offload) || is_packet_offload) {
350 NL_SET_ERR_MSG_WEAK(extack, "Device failed to offload this state");
351 return err;
352 }
353 }
354
355 return 0;
356 }
357 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
358
xfrm_dev_policy_add(struct net * net,struct xfrm_policy * xp,struct xfrm_user_offload * xuo,u8 dir,struct netlink_ext_ack * extack)359 int xfrm_dev_policy_add(struct net *net, struct xfrm_policy *xp,
360 struct xfrm_user_offload *xuo, u8 dir,
361 struct netlink_ext_ack *extack)
362 {
363 struct xfrm_dev_offload *xdo = &xp->xdo;
364 struct net_device *dev;
365 int err;
366
367 if (!xuo->flags || xuo->flags & ~XFRM_OFFLOAD_PACKET) {
368 /* We support only packet offload mode and it means
369 * that user must set XFRM_OFFLOAD_PACKET bit.
370 */
371 NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
372 return -EINVAL;
373 }
374
375 dev = dev_get_by_index(net, xuo->ifindex);
376 if (!dev)
377 return -EINVAL;
378
379 if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_policy_add) {
380 xdo->dev = NULL;
381 dev_put(dev);
382 NL_SET_ERR_MSG(extack, "Policy offload is not supported");
383 return -EINVAL;
384 }
385
386 xdo->dev = dev;
387 netdev_tracker_alloc(dev, &xdo->dev_tracker, GFP_ATOMIC);
388 xdo->type = XFRM_DEV_OFFLOAD_PACKET;
389 switch (dir) {
390 case XFRM_POLICY_IN:
391 xdo->dir = XFRM_DEV_OFFLOAD_IN;
392 break;
393 case XFRM_POLICY_OUT:
394 xdo->dir = XFRM_DEV_OFFLOAD_OUT;
395 break;
396 case XFRM_POLICY_FWD:
397 xdo->dir = XFRM_DEV_OFFLOAD_FWD;
398 break;
399 default:
400 xdo->dev = NULL;
401 netdev_put(dev, &xdo->dev_tracker);
402 NL_SET_ERR_MSG(extack, "Unrecognized offload direction");
403 return -EINVAL;
404 }
405
406 err = dev->xfrmdev_ops->xdo_dev_policy_add(xp, extack);
407 if (err) {
408 xdo->dev = NULL;
409 xdo->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
410 xdo->dir = 0;
411 netdev_put(dev, &xdo->dev_tracker);
412 NL_SET_ERR_MSG_WEAK(extack, "Device failed to offload this policy");
413 return err;
414 }
415
416 return 0;
417 }
418 EXPORT_SYMBOL_GPL(xfrm_dev_policy_add);
419
xfrm_dev_offload_ok(struct sk_buff * skb,struct xfrm_state * x)420 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
421 {
422 int mtu;
423 struct dst_entry *dst = skb_dst(skb);
424 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
425 struct net_device *dev = x->xso.dev;
426 bool check_tunnel_size;
427
428 if (!x->type_offload ||
429 (x->xso.type == XFRM_DEV_OFFLOAD_UNSPECIFIED && x->encap))
430 return false;
431
432 if ((!dev || dev == xfrm_dst_path(dst)->dev) &&
433 !xdst->child->xfrm) {
434 mtu = xfrm_state_mtu(x, xdst->child_mtu_cached);
435 if (skb->len <= mtu)
436 goto ok;
437
438 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
439 goto ok;
440 }
441
442 return false;
443
444 ok:
445 if (!dev)
446 return true;
447
448 check_tunnel_size = x->xso.type == XFRM_DEV_OFFLOAD_PACKET &&
449 x->props.mode == XFRM_MODE_TUNNEL;
450 switch (skb_dst(skb)->ops->family) {
451 case AF_INET:
452 /* Check for IPv4 options */
453 if (ip_hdr(skb)->ihl != 5)
454 return false;
455 if (check_tunnel_size && xfrm4_tunnel_check_size(skb))
456 return false;
457 break;
458 case AF_INET6:
459 /* Check for IPv6 extensions */
460 if (ipv6_ext_hdr(ipv6_hdr(skb)->nexthdr))
461 return false;
462 if (check_tunnel_size && xfrm6_tunnel_check_size(skb))
463 return false;
464 break;
465 default:
466 break;
467 }
468
469 if (dev->xfrmdev_ops->xdo_dev_offload_ok)
470 return dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
471
472 return true;
473 }
474 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
475
xfrm_dev_resume(struct sk_buff * skb)476 void xfrm_dev_resume(struct sk_buff *skb)
477 {
478 struct net_device *dev = skb->dev;
479 int ret = NETDEV_TX_BUSY;
480 struct netdev_queue *txq;
481 struct softnet_data *sd;
482 unsigned long flags;
483
484 rcu_read_lock();
485 txq = netdev_core_pick_tx(dev, skb, NULL);
486
487 HARD_TX_LOCK(dev, txq, smp_processor_id());
488 if (!netif_xmit_frozen_or_stopped(txq))
489 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
490 HARD_TX_UNLOCK(dev, txq);
491
492 if (!dev_xmit_complete(ret)) {
493 local_irq_save(flags);
494 sd = this_cpu_ptr(&softnet_data);
495 skb_queue_tail(&sd->xfrm_backlog, skb);
496 raise_softirq_irqoff(NET_TX_SOFTIRQ);
497 local_irq_restore(flags);
498 }
499 rcu_read_unlock();
500 }
501 EXPORT_SYMBOL_GPL(xfrm_dev_resume);
502
xfrm_dev_backlog(struct softnet_data * sd)503 void xfrm_dev_backlog(struct softnet_data *sd)
504 {
505 struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
506 struct sk_buff_head list;
507 struct sk_buff *skb;
508
509 if (skb_queue_empty(xfrm_backlog))
510 return;
511
512 __skb_queue_head_init(&list);
513
514 spin_lock(&xfrm_backlog->lock);
515 skb_queue_splice_init(xfrm_backlog, &list);
516 spin_unlock(&xfrm_backlog->lock);
517
518 while (!skb_queue_empty(&list)) {
519 skb = __skb_dequeue(&list);
520 xfrm_dev_resume(skb);
521 }
522
523 }
524 #endif
525
xfrm_api_check(struct net_device * dev)526 static int xfrm_api_check(struct net_device *dev)
527 {
528 #ifdef CONFIG_XFRM_OFFLOAD
529 if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
530 !(dev->features & NETIF_F_HW_ESP))
531 return NOTIFY_BAD;
532
533 if ((dev->features & NETIF_F_HW_ESP) &&
534 (!(dev->xfrmdev_ops &&
535 dev->xfrmdev_ops->xdo_dev_state_add &&
536 dev->xfrmdev_ops->xdo_dev_state_delete)))
537 return NOTIFY_BAD;
538 #else
539 if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
540 return NOTIFY_BAD;
541 #endif
542
543 return NOTIFY_DONE;
544 }
545
xfrm_dev_down(struct net_device * dev)546 static int xfrm_dev_down(struct net_device *dev)
547 {
548 if (dev->features & NETIF_F_HW_ESP) {
549 xfrm_dev_state_flush(dev_net(dev), dev, true);
550 xfrm_dev_policy_flush(dev_net(dev), dev, true);
551 }
552
553 return NOTIFY_DONE;
554 }
555
xfrm_dev_unregister(struct net_device * dev)556 static int xfrm_dev_unregister(struct net_device *dev)
557 {
558 xfrm_dev_state_flush(dev_net(dev), dev, true);
559 xfrm_dev_policy_flush(dev_net(dev), dev, true);
560
561 return NOTIFY_DONE;
562 }
563
xfrm_dev_event(struct notifier_block * this,unsigned long event,void * ptr)564 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
565 {
566 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
567
568 switch (event) {
569 case NETDEV_REGISTER:
570 return xfrm_api_check(dev);
571
572 case NETDEV_FEAT_CHANGE:
573 return xfrm_api_check(dev);
574
575 case NETDEV_DOWN:
576 return xfrm_dev_down(dev);
577
578 case NETDEV_UNREGISTER:
579 return xfrm_dev_unregister(dev);
580 }
581 return NOTIFY_DONE;
582 }
583
584 static struct notifier_block xfrm_dev_notifier = {
585 .notifier_call = xfrm_dev_event,
586 };
587
xfrm_dev_init(void)588 void __init xfrm_dev_init(void)
589 {
590 register_netdevice_notifier(&xfrm_dev_notifier);
591 }
592