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