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 /* This skb was already validated on the upper/virtual dev */
136 if ((x->xso.dev != dev) && (x->xso.real_dev == dev))
137 return skb;
138
139 local_irq_save(flags);
140 sd = this_cpu_ptr(&softnet_data);
141 err = !skb_queue_empty(&sd->xfrm_backlog);
142 local_irq_restore(flags);
143
144 if (err) {
145 *again = true;
146 return skb;
147 }
148
149 if (skb_is_gso(skb) && (unlikely(x->xso.dev != dev) ||
150 unlikely(xmit_xfrm_check_overflow(skb)))) {
151 struct sk_buff *segs;
152
153 /* Packet got rerouted, fixup features and segment it. */
154 esp_features = esp_features & ~(NETIF_F_HW_ESP | NETIF_F_GSO_ESP);
155
156 segs = skb_gso_segment(skb, esp_features);
157 if (IS_ERR(segs)) {
158 kfree_skb(skb);
159 dev_core_stats_tx_dropped_inc(dev);
160 return NULL;
161 } else {
162 consume_skb(skb);
163 skb = segs;
164 }
165 }
166
167 if (!skb->next) {
168 esp_features |= skb->dev->gso_partial_features;
169 xfrm_outer_mode_prep(x, skb);
170
171 xo->flags |= XFRM_DEV_RESUME;
172
173 err = x->type_offload->xmit(x, skb, esp_features);
174 if (err) {
175 if (err == -EINPROGRESS)
176 return NULL;
177
178 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
179 kfree_skb(skb);
180 return NULL;
181 }
182
183 skb_push(skb, skb->data - skb_mac_header(skb));
184
185 return skb;
186 }
187
188 skb_list_walk_safe(skb, skb2, nskb) {
189 esp_features |= skb->dev->gso_partial_features;
190 skb_mark_not_on_list(skb2);
191
192 xo = xfrm_offload(skb2);
193 xo->flags |= XFRM_DEV_RESUME;
194
195 xfrm_outer_mode_prep(x, skb2);
196
197 err = x->type_offload->xmit(x, skb2, esp_features);
198 if (!err) {
199 skb2->next = nskb;
200 } else if (err != -EINPROGRESS) {
201 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
202 skb2->next = nskb;
203 kfree_skb_list(skb2);
204 return NULL;
205 } else {
206 if (skb == skb2)
207 skb = nskb;
208 else
209 pskb->next = nskb;
210
211 continue;
212 }
213
214 skb_push(skb2, skb2->data - skb_mac_header(skb2));
215 pskb = skb2;
216 }
217
218 return skb;
219 }
220 EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
221
xfrm_dev_state_add(struct net * net,struct xfrm_state * x,struct xfrm_user_offload * xuo,struct netlink_ext_ack * extack)222 int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
223 struct xfrm_user_offload *xuo,
224 struct netlink_ext_ack *extack)
225 {
226 int err;
227 struct dst_entry *dst;
228 struct net_device *dev;
229 struct xfrm_dev_offload *xso = &x->xso;
230 xfrm_address_t *saddr;
231 xfrm_address_t *daddr;
232
233 if (!x->type_offload) {
234 NL_SET_ERR_MSG(extack, "Type doesn't support offload");
235 return -EINVAL;
236 }
237
238 /* We don't yet support UDP encapsulation and TFC padding. */
239 if (x->encap || x->tfcpad) {
240 NL_SET_ERR_MSG(extack, "Encapsulation and TFC padding can't be offloaded");
241 return -EINVAL;
242 }
243
244 if (xuo->flags & ~(XFRM_OFFLOAD_IPV6 | XFRM_OFFLOAD_INBOUND)) {
245 NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
246 return -EINVAL;
247 }
248
249 dev = dev_get_by_index(net, xuo->ifindex);
250 if (!dev) {
251 if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
252 saddr = &x->props.saddr;
253 daddr = &x->id.daddr;
254 } else {
255 saddr = &x->id.daddr;
256 daddr = &x->props.saddr;
257 }
258
259 dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
260 x->props.family,
261 xfrm_smark_get(0, x));
262 if (IS_ERR(dst))
263 return 0;
264
265 dev = dst->dev;
266
267 dev_hold(dev);
268 dst_release(dst);
269 }
270
271 if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
272 xso->dev = NULL;
273 dev_put(dev);
274 return 0;
275 }
276
277 if (x->props.flags & XFRM_STATE_ESN &&
278 !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
279 NL_SET_ERR_MSG(extack, "Device doesn't support offload with ESN");
280 xso->dev = NULL;
281 dev_put(dev);
282 return -EINVAL;
283 }
284
285 xso->dev = dev;
286 netdev_tracker_alloc(dev, &xso->dev_tracker, GFP_ATOMIC);
287 xso->real_dev = dev;
288
289 if (xuo->flags & XFRM_OFFLOAD_INBOUND)
290 xso->dir = XFRM_DEV_OFFLOAD_IN;
291 else
292 xso->dir = XFRM_DEV_OFFLOAD_OUT;
293
294 err = dev->xfrmdev_ops->xdo_dev_state_add(x);
295 if (err) {
296 xso->dev = NULL;
297 xso->dir = 0;
298 xso->real_dev = NULL;
299 netdev_put(dev, &xso->dev_tracker);
300
301 if (err != -EOPNOTSUPP) {
302 NL_SET_ERR_MSG(extack, "Device failed to offload this state");
303 return err;
304 }
305 }
306
307 return 0;
308 }
309 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
310
xfrm_dev_offload_ok(struct sk_buff * skb,struct xfrm_state * x)311 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
312 {
313 int mtu;
314 struct dst_entry *dst = skb_dst(skb);
315 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
316 struct net_device *dev = x->xso.dev;
317
318 if (!x->type_offload || x->encap)
319 return false;
320
321 if ((!dev || (dev == xfrm_dst_path(dst)->dev)) &&
322 (!xdst->child->xfrm)) {
323 mtu = xfrm_state_mtu(x, xdst->child_mtu_cached);
324 if (skb->len <= mtu)
325 goto ok;
326
327 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
328 goto ok;
329 }
330
331 return false;
332
333 ok:
334 if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
335 return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
336
337 return true;
338 }
339 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
340
xfrm_dev_resume(struct sk_buff * skb)341 void xfrm_dev_resume(struct sk_buff *skb)
342 {
343 struct net_device *dev = skb->dev;
344 int ret = NETDEV_TX_BUSY;
345 struct netdev_queue *txq;
346 struct softnet_data *sd;
347 unsigned long flags;
348
349 rcu_read_lock();
350 txq = netdev_core_pick_tx(dev, skb, NULL);
351
352 HARD_TX_LOCK(dev, txq, smp_processor_id());
353 if (!netif_xmit_frozen_or_stopped(txq))
354 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
355 HARD_TX_UNLOCK(dev, txq);
356
357 if (!dev_xmit_complete(ret)) {
358 local_irq_save(flags);
359 sd = this_cpu_ptr(&softnet_data);
360 skb_queue_tail(&sd->xfrm_backlog, skb);
361 raise_softirq_irqoff(NET_TX_SOFTIRQ);
362 local_irq_restore(flags);
363 }
364 rcu_read_unlock();
365 }
366 EXPORT_SYMBOL_GPL(xfrm_dev_resume);
367
xfrm_dev_backlog(struct softnet_data * sd)368 void xfrm_dev_backlog(struct softnet_data *sd)
369 {
370 struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
371 struct sk_buff_head list;
372 struct sk_buff *skb;
373
374 if (skb_queue_empty(xfrm_backlog))
375 return;
376
377 __skb_queue_head_init(&list);
378
379 spin_lock(&xfrm_backlog->lock);
380 skb_queue_splice_init(xfrm_backlog, &list);
381 spin_unlock(&xfrm_backlog->lock);
382
383 while (!skb_queue_empty(&list)) {
384 skb = __skb_dequeue(&list);
385 xfrm_dev_resume(skb);
386 }
387
388 }
389 #endif
390
xfrm_api_check(struct net_device * dev)391 static int xfrm_api_check(struct net_device *dev)
392 {
393 #ifdef CONFIG_XFRM_OFFLOAD
394 if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
395 !(dev->features & NETIF_F_HW_ESP))
396 return NOTIFY_BAD;
397
398 if ((dev->features & NETIF_F_HW_ESP) &&
399 (!(dev->xfrmdev_ops &&
400 dev->xfrmdev_ops->xdo_dev_state_add &&
401 dev->xfrmdev_ops->xdo_dev_state_delete)))
402 return NOTIFY_BAD;
403 #else
404 if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
405 return NOTIFY_BAD;
406 #endif
407
408 return NOTIFY_DONE;
409 }
410
xfrm_dev_down(struct net_device * dev)411 static int xfrm_dev_down(struct net_device *dev)
412 {
413 if (dev->features & NETIF_F_HW_ESP)
414 xfrm_dev_state_flush(dev_net(dev), dev, true);
415
416 return NOTIFY_DONE;
417 }
418
xfrm_dev_event(struct notifier_block * this,unsigned long event,void * ptr)419 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
420 {
421 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
422
423 switch (event) {
424 case NETDEV_REGISTER:
425 return xfrm_api_check(dev);
426
427 case NETDEV_FEAT_CHANGE:
428 return xfrm_api_check(dev);
429
430 case NETDEV_DOWN:
431 case NETDEV_UNREGISTER:
432 return xfrm_dev_down(dev);
433 }
434 return NOTIFY_DONE;
435 }
436
437 static struct notifier_block xfrm_dev_notifier = {
438 .notifier_call = xfrm_dev_event,
439 };
440
xfrm_dev_init(void)441 void __init xfrm_dev_init(void)
442 {
443 register_netdevice_notifier(&xfrm_dev_notifier);
444 }
445
