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
23static 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, len: skb_transport_offset(skb) + x->props.header_len);
33}
34
35static 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, len: skb->mac_len + x->props.header_len);
46}
47
48static 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, len: skb->mac_len + hsize + (x->props.header_len - phlen));
65}
66
67/* Adjust pointers into the packet when IPsec is done at layer2 */
68static 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 hsize: sizeof(struct iphdr));
75 if (x->outer_mode.family == AF_INET6)
76 return __xfrm_mode_tunnel_prep(x, skb,
77 hsize: 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 hsize: sizeof(struct iphdr));
83 if (x->outer_mode.family == AF_INET6)
84 return __xfrm_transport_prep(x, skb,
85 hsize: 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 hsize: sizeof(struct iphdr));
91 if (x->outer_mode.family == AF_INET6)
92 return __xfrm_mode_beet_prep(x, skb,
93 hsize: sizeof(struct ipv6hdr));
94 break;
95 case XFRM_MODE_ROUTEOPTIMIZATION:
96 case XFRM_MODE_IN_TRIGGER:
97 break;
98 }
99}
100
101static 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
113struct 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(list: &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, features: esp_features);
168 if (IS_ERR(ptr: 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, len: 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(skb: skb2);
202
203 xo = xfrm_offload(skb: skb2);
204 xo->flags |= XFRM_DEV_RESUME;
205
206 xfrm_outer_mode_prep(x, skb: 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(segs: 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(skb: skb2, len: skb2->data - skb_mac_header(skb: skb2));
226 pskb = skb2;
227 }
228
229 return skb;
230}
231EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
232
233int 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, ifindex: xuo->ifindex);
265 if (!dev) {
266 if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
267 saddr = &x->props.saddr;
268 daddr = &x->id.daddr;
269 } else {
270 saddr = &x->id.daddr;
271 daddr = &x->props.saddr;
272 }
273
274 dst = __xfrm_dst_lookup(net, tos: 0, oif: 0, saddr, daddr,
275 family: x->props.family,
276 mark: xfrm_smark_get(mark: 0, x));
277 if (IS_ERR(ptr: dst))
278 return (is_packet_offload) ? -EINVAL : 0;
279
280 dev = dst->dev;
281
282 dev_hold(dev);
283 dst_release(dst);
284 }
285
286 if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
287 xso->dev = NULL;
288 dev_put(dev);
289 return (is_packet_offload) ? -EINVAL : 0;
290 }
291
292 if (!is_packet_offload && x->props.flags & XFRM_STATE_ESN &&
293 !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
294 NL_SET_ERR_MSG(extack, "Device doesn't support offload with ESN");
295 xso->dev = NULL;
296 dev_put(dev);
297 return -EINVAL;
298 }
299
300 xso->dev = dev;
301 netdev_tracker_alloc(dev, tracker: &xso->dev_tracker, GFP_ATOMIC);
302 xso->real_dev = dev;
303
304 if (xuo->flags & XFRM_OFFLOAD_INBOUND)
305 xso->dir = XFRM_DEV_OFFLOAD_IN;
306 else
307 xso->dir = XFRM_DEV_OFFLOAD_OUT;
308
309 if (is_packet_offload)
310 xso->type = XFRM_DEV_OFFLOAD_PACKET;
311 else
312 xso->type = XFRM_DEV_OFFLOAD_CRYPTO;
313
314 err = dev->xfrmdev_ops->xdo_dev_state_add(x, extack);
315 if (err) {
316 xso->dev = NULL;
317 xso->dir = 0;
318 xso->real_dev = NULL;
319 netdev_put(dev, tracker: &xso->dev_tracker);
320 xso->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
321
322 /* User explicitly requested packet offload mode and configured
323 * policy in addition to the XFRM state. So be civil to users,
324 * and return an error instead of taking fallback path.
325 *
326 * This WARN_ON() can be seen as a documentation for driver
327 * authors to do not return -EOPNOTSUPP in packet offload mode.
328 */
329 WARN_ON(err == -EOPNOTSUPP && is_packet_offload);
330 if (err != -EOPNOTSUPP || is_packet_offload) {
331 NL_SET_ERR_MSG_WEAK(extack, "Device failed to offload this state");
332 return err;
333 }
334 }
335
336 return 0;
337}
338EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
339
340int xfrm_dev_policy_add(struct net *net, struct xfrm_policy *xp,
341 struct xfrm_user_offload *xuo, u8 dir,
342 struct netlink_ext_ack *extack)
343{
344 struct xfrm_dev_offload *xdo = &xp->xdo;
345 struct net_device *dev;
346 int err;
347
348 if (!xuo->flags || xuo->flags & ~XFRM_OFFLOAD_PACKET) {
349 /* We support only packet offload mode and it means
350 * that user must set XFRM_OFFLOAD_PACKET bit.
351 */
352 NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
353 return -EINVAL;
354 }
355
356 dev = dev_get_by_index(net, ifindex: xuo->ifindex);
357 if (!dev)
358 return -EINVAL;
359
360 if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_policy_add) {
361 xdo->dev = NULL;
362 dev_put(dev);
363 NL_SET_ERR_MSG(extack, "Policy offload is not supported");
364 return -EINVAL;
365 }
366
367 xdo->dev = dev;
368 netdev_tracker_alloc(dev, tracker: &xdo->dev_tracker, GFP_ATOMIC);
369 xdo->real_dev = dev;
370 xdo->type = XFRM_DEV_OFFLOAD_PACKET;
371 switch (dir) {
372 case XFRM_POLICY_IN:
373 xdo->dir = XFRM_DEV_OFFLOAD_IN;
374 break;
375 case XFRM_POLICY_OUT:
376 xdo->dir = XFRM_DEV_OFFLOAD_OUT;
377 break;
378 case XFRM_POLICY_FWD:
379 xdo->dir = XFRM_DEV_OFFLOAD_FWD;
380 break;
381 default:
382 xdo->dev = NULL;
383 netdev_put(dev, tracker: &xdo->dev_tracker);
384 NL_SET_ERR_MSG(extack, "Unrecognized offload direction");
385 return -EINVAL;
386 }
387
388 err = dev->xfrmdev_ops->xdo_dev_policy_add(xp, extack);
389 if (err) {
390 xdo->dev = NULL;
391 xdo->real_dev = NULL;
392 xdo->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
393 xdo->dir = 0;
394 netdev_put(dev, tracker: &xdo->dev_tracker);
395 NL_SET_ERR_MSG_WEAK(extack, "Device failed to offload this policy");
396 return err;
397 }
398
399 return 0;
400}
401EXPORT_SYMBOL_GPL(xfrm_dev_policy_add);
402
403bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
404{
405 int mtu;
406 struct dst_entry *dst = skb_dst(skb);
407 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
408 struct net_device *dev = x->xso.dev;
409
410 if (!x->type_offload || x->encap)
411 return false;
412
413 if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET ||
414 ((!dev || (dev == xfrm_dst_path(dst)->dev)) &&
415 !xdst->child->xfrm)) {
416 mtu = xfrm_state_mtu(x, mtu: xdst->child_mtu_cached);
417 if (skb->len <= mtu)
418 goto ok;
419
420 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
421 goto ok;
422 }
423
424 return false;
425
426ok:
427 if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
428 return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
429
430 return true;
431}
432EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
433
434void xfrm_dev_resume(struct sk_buff *skb)
435{
436 struct net_device *dev = skb->dev;
437 int ret = NETDEV_TX_BUSY;
438 struct netdev_queue *txq;
439 struct softnet_data *sd;
440 unsigned long flags;
441
442 rcu_read_lock();
443 txq = netdev_core_pick_tx(dev, skb, NULL);
444
445 HARD_TX_LOCK(dev, txq, smp_processor_id());
446 if (!netif_xmit_frozen_or_stopped(dev_queue: txq))
447 skb = dev_hard_start_xmit(skb, dev, txq, ret: &ret);
448 HARD_TX_UNLOCK(dev, txq);
449
450 if (!dev_xmit_complete(rc: ret)) {
451 local_irq_save(flags);
452 sd = this_cpu_ptr(&softnet_data);
453 skb_queue_tail(list: &sd->xfrm_backlog, newsk: skb);
454 raise_softirq_irqoff(nr: NET_TX_SOFTIRQ);
455 local_irq_restore(flags);
456 }
457 rcu_read_unlock();
458}
459EXPORT_SYMBOL_GPL(xfrm_dev_resume);
460
461void xfrm_dev_backlog(struct softnet_data *sd)
462{
463 struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
464 struct sk_buff_head list;
465 struct sk_buff *skb;
466
467 if (skb_queue_empty(list: xfrm_backlog))
468 return;
469
470 __skb_queue_head_init(list: &list);
471
472 spin_lock(lock: &xfrm_backlog->lock);
473 skb_queue_splice_init(list: xfrm_backlog, head: &list);
474 spin_unlock(lock: &xfrm_backlog->lock);
475
476 while (!skb_queue_empty(list: &list)) {
477 skb = __skb_dequeue(list: &list);
478 xfrm_dev_resume(skb);
479 }
480
481}
482#endif
483
484static int xfrm_api_check(struct net_device *dev)
485{
486#ifdef CONFIG_XFRM_OFFLOAD
487 if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
488 !(dev->features & NETIF_F_HW_ESP))
489 return NOTIFY_BAD;
490
491 if ((dev->features & NETIF_F_HW_ESP) &&
492 (!(dev->xfrmdev_ops &&
493 dev->xfrmdev_ops->xdo_dev_state_add &&
494 dev->xfrmdev_ops->xdo_dev_state_delete)))
495 return NOTIFY_BAD;
496#else
497 if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
498 return NOTIFY_BAD;
499#endif
500
501 return NOTIFY_DONE;
502}
503
504static int xfrm_dev_down(struct net_device *dev)
505{
506 if (dev->features & NETIF_F_HW_ESP) {
507 xfrm_dev_state_flush(net: dev_net(dev), dev, task_valid: true);
508 xfrm_dev_policy_flush(net: dev_net(dev), dev, task_valid: true);
509 }
510
511 return NOTIFY_DONE;
512}
513
514static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
515{
516 struct net_device *dev = netdev_notifier_info_to_dev(info: ptr);
517
518 switch (event) {
519 case NETDEV_REGISTER:
520 return xfrm_api_check(dev);
521
522 case NETDEV_FEAT_CHANGE:
523 return xfrm_api_check(dev);
524
525 case NETDEV_DOWN:
526 case NETDEV_UNREGISTER:
527 return xfrm_dev_down(dev);
528 }
529 return NOTIFY_DONE;
530}
531
532static struct notifier_block xfrm_dev_notifier = {
533 .notifier_call = xfrm_dev_event,
534};
535
536void __init xfrm_dev_init(void)
537{
538 register_netdevice_notifier(nb: &xfrm_dev_notifier);
539}
540

source code of linux/net/xfrm/xfrm_device.c