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