net/xfrm/xfrm_device.c

   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
  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         pskb_pull(skb, skb->mac_len + hsize + x->props.header_len);
  29
  30         if (xo->flags & XFRM_GSO_SEGMENT) {
  31                 skb_reset_transport_header(skb);
  32                 skb->transport_header -= x->props.header_len;
  33         }
  34 }
  35
  36 static void __xfrm_mode_tunnel_prep(struct xfrm_state *x, struct sk_buff *skb,
  37                                     unsigned int hsize)
  38
  39 {
  40         struct xfrm_offload *xo = xfrm_offload(skb);
  41
  42         if (xo->flags & XFRM_GSO_SEGMENT)
  43                 skb->transport_header = skb->network_header + hsize;
  44
  45         skb_reset_mac_len(skb);
  46         pskb_pull(skb, skb->mac_len + x->props.header_len);
  47 }
  48
  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 */
  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_TUNNEL:
  73                 if (x->outer_mode.family == AF_INET)
  74                         return __xfrm_mode_tunnel_prep(x, skb,
  75                                                        sizeof(struct iphdr));
  76                 if (x->outer_mode.family == AF_INET6)
  77                         return __xfrm_mode_tunnel_prep(x, skb,
  78                                                        sizeof(struct ipv6hdr));
  79                 break;
  80         case XFRM_MODE_TRANSPORT:
  81                 if (x->outer_mode.family == AF_INET)
  82                         return __xfrm_transport_prep(x, skb,
  83                                                      sizeof(struct iphdr));
  84                 if (x->outer_mode.family == AF_INET6)
  85                         return __xfrm_transport_prep(x, skb,
  86                                                      sizeof(struct ipv6hdr));
  87                 break;
  88         case XFRM_MODE_BEET:
  89                 if (x->outer_mode.family == AF_INET)
  90                         return __xfrm_mode_beet_prep(x, skb,
  91                                                      sizeof(struct iphdr));
  92                 if (x->outer_mode.family == AF_INET6)
  93                         return __xfrm_mode_beet_prep(x, skb,
  94                                                      sizeof(struct ipv6hdr));
  95                 break;
  96         case XFRM_MODE_ROUTEOPTIMIZATION:
  97         case XFRM_MODE_IN_TRIGGER:
  98                 break;
  99         }
 100 }
 101
 102 struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features, bool *again)
 103 {
 104         int err;
 105         unsigned long flags;
 106         struct xfrm_state *x;
 107         struct softnet_data *sd;
 108         struct sk_buff *skb2, *nskb, *pskb = NULL;
 109         netdev_features_t esp_features = features;
 110         struct xfrm_offload *xo = xfrm_offload(skb);
 111         struct sec_path *sp;
 112
 113         if (!xo)
 114                 return skb;
 115
 116         if (!(features & NETIF_F_HW_ESP))
 117                 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
 118
 119         sp = skb_sec_path(skb);
 120         x = sp->xvec[sp->len - 1];
 121         if (xo->flags & XFRM_GRO || x->xso.flags & XFRM_OFFLOAD_INBOUND)
 122                 return skb;
 123
 124         local_irq_save(flags);
 125         sd = this_cpu_ptr(&softnet_data);
 126         err = !skb_queue_empty(&sd->xfrm_backlog);
 127         local_irq_restore(flags);
 128
 129         if (err) {
 130                 *again = true;
 131                 return skb;
 132         }
 133
 134         if (skb_is_gso(skb)) {
 135                 struct net_device *dev = skb->dev;
 136
 137                 if (unlikely(x->xso.dev != dev)) {
 138                         struct sk_buff *segs;
 139
 140                         /* Packet got rerouted, fixup features and segment it. */
 141                         esp_features = esp_features & ~(NETIF_F_HW_ESP
 142                                                         | NETIF_F_GSO_ESP);
 143
 144                         segs = skb_gso_segment(skb, esp_features);
 145                         if (IS_ERR(segs)) {
 146                                 kfree_skb(skb);
 147                                 atomic_long_inc(&dev->tx_dropped);
 148                                 return NULL;
 149                         } else {
 150                                 consume_skb(skb);
 151                                 skb = segs;
 152                         }
 153                 }
 154         }
 155
 156         if (!skb->next) {
 157                 esp_features |= skb->dev->gso_partial_features;
 158                 xfrm_outer_mode_prep(x, skb);
 159
 160                 xo->flags |= XFRM_DEV_RESUME;
 161
 162                 err = x->type_offload->xmit(x, skb, esp_features);
 163                 if (err) {
 164                         if (err == -EINPROGRESS)
 165                                 return NULL;
 166
 167                         XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
 168                         kfree_skb(skb);
 169                         return NULL;
 170                 }
 171
 172                 skb_push(skb, skb->data - skb_mac_header(skb));
 173
 174                 return skb;
 175         }
 176
 177         skb_list_walk_safe(skb, skb2, nskb) {
 178                 esp_features |= skb->dev->gso_partial_features;
 179                 skb_mark_not_on_list(skb2);
 180
 181                 xo = xfrm_offload(skb2);
 182                 xo->flags |= XFRM_DEV_RESUME;
 183
 184                 xfrm_outer_mode_prep(x, skb2);
 185
 186                 err = x->type_offload->xmit(x, skb2, esp_features);
 187                 if (!err) {
 188                         skb2->next = nskb;
 189                 } else if (err != -EINPROGRESS) {
 190                         XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
 191                         skb2->next = nskb;
 192                         kfree_skb_list(skb2);
 193                         return NULL;
 194                 } else {
 195                         if (skb == skb2)
 196                                 skb = nskb;
 197                         else
 198                                 pskb->next = nskb;
 199
 200                         continue;
 201                 }
 202
 203                 skb_push(skb2, skb2->data - skb_mac_header(skb2));
 204                 pskb = skb2;
 205         }
 206
 207         return skb;
 208 }
 209 EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
 210
 211 int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 212                        struct xfrm_user_offload *xuo)
 213 {
 214         int err;
 215         struct dst_entry *dst;
 216         struct net_device *dev;
 217         struct xfrm_state_offload *xso = &x->xso;
 218         xfrm_address_t *saddr;
 219         xfrm_address_t *daddr;
 220
 221         if (!x->type_offload)
 222                 return -EINVAL;
 223
 224         /* We don't yet support UDP encapsulation and TFC padding. */
 225         if (x->encap || x->tfcpad)
 226                 return -EINVAL;
 227
 228         dev = dev_get_by_index(net, xuo->ifindex);
 229         if (!dev) {
 230                 if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
 231                         saddr = &x->props.saddr;
 232                         daddr = &x->id.daddr;
 233                 } else {
 234                         saddr = &x->id.daddr;
 235                         daddr = &x->props.saddr;
 236                 }
 237
 238                 dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
 239                                         x->props.family,
 240                                         xfrm_smark_get(0, x));
 241                 if (IS_ERR(dst))
 242                         return 0;
 243
 244                 dev = dst->dev;
 245
 246                 dev_hold(dev);
 247                 dst_release(dst);
 248         }
 249
 250         if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
 251                 xso->dev = NULL;
 252                 dev_put(dev);
 253                 return 0;
 254         }
 255
 256         if (x->props.flags & XFRM_STATE_ESN &&
 257             !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
 258                 xso->dev = NULL;
 259                 dev_put(dev);
 260                 return -EINVAL;
 261         }
 262
 263         xso->dev = dev;
 264         xso->num_exthdrs = 1;
 265         xso->flags = xuo->flags;
 266
 267         err = dev->xfrmdev_ops->xdo_dev_state_add(x);
 268         if (err) {
 269                 xso->num_exthdrs = 0;
 270                 xso->flags = 0;
 271                 xso->dev = NULL;
 272                 dev_put(dev);
 273
 274                 if (err != -EOPNOTSUPP)
 275                         return err;
 276         }
 277
 278         return 0;
 279 }
 280 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
 281
 282 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 283 {
 284         int mtu;
 285         struct dst_entry *dst = skb_dst(skb);
 286         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 287         struct net_device *dev = x->xso.dev;
 288
 289         if (!x->type_offload || x->encap)
 290                 return false;
 291
 292         if ((!dev || (dev == xfrm_dst_path(dst)->dev)) &&
 293             (!xdst->child->xfrm)) {
 294                 mtu = xfrm_state_mtu(x, xdst->child_mtu_cached);
 295                 if (skb->len <= mtu)
 296                         goto ok;
 297
 298                 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 299                         goto ok;
 300         }
 301
 302         return false;
 303
 304 ok:
 305         if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
 306                 return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
 307
 308         return true;
 309 }
 310 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
 311
 312 void xfrm_dev_resume(struct sk_buff *skb)
 313 {
 314         struct net_device *dev = skb->dev;
 315         int ret = NETDEV_TX_BUSY;
 316         struct netdev_queue *txq;
 317         struct softnet_data *sd;
 318         unsigned long flags;
 319
 320         rcu_read_lock();
 321         txq = netdev_core_pick_tx(dev, skb, NULL);
 322
 323         HARD_TX_LOCK(dev, txq, smp_processor_id());
 324         if (!netif_xmit_frozen_or_stopped(txq))
 325                 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
 326         HARD_TX_UNLOCK(dev, txq);
 327
 328         if (!dev_xmit_complete(ret)) {
 329                 local_irq_save(flags);
 330                 sd = this_cpu_ptr(&softnet_data);
 331                 skb_queue_tail(&sd->xfrm_backlog, skb);
 332                 raise_softirq_irqoff(NET_TX_SOFTIRQ);
 333                 local_irq_restore(flags);
 334         }
 335         rcu_read_unlock();
 336 }
 337 EXPORT_SYMBOL_GPL(xfrm_dev_resume);
 338
 339 void xfrm_dev_backlog(struct softnet_data *sd)
 340 {
 341         struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
 342         struct sk_buff_head list;
 343         struct sk_buff *skb;
 344
 345         if (skb_queue_empty(xfrm_backlog))
 346                 return;
 347
 348         __skb_queue_head_init(&list);
 349
 350         spin_lock(&xfrm_backlog->lock);
 351         skb_queue_splice_init(xfrm_backlog, &list);
 352         spin_unlock(&xfrm_backlog->lock);
 353
 354         while (!skb_queue_empty(&list)) {
 355                 skb = __skb_dequeue(&list);
 356                 xfrm_dev_resume(skb);
 357         }
 358
 359 }
 360 #endif
 361
 362 static int xfrm_api_check(struct net_device *dev)
 363 {
 364 #ifdef CONFIG_XFRM_OFFLOAD
 365         if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 366             !(dev->features & NETIF_F_HW_ESP))
 367                 return NOTIFY_BAD;
 368
 369         if ((dev->features & NETIF_F_HW_ESP) &&
 370             (!(dev->xfrmdev_ops &&
 371                dev->xfrmdev_ops->xdo_dev_state_add &&
 372                dev->xfrmdev_ops->xdo_dev_state_delete)))
 373                 return NOTIFY_BAD;
 374 #else
 375         if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
 376                 return NOTIFY_BAD;
 377 #endif
 378
 379         return NOTIFY_DONE;
 380 }
 381
 382 static int xfrm_dev_register(struct net_device *dev)
 383 {
 384         return xfrm_api_check(dev);
 385 }
 386
 387 static int xfrm_dev_feat_change(struct net_device *dev)
 388 {
 389         return xfrm_api_check(dev);
 390 }
 391
 392 static int xfrm_dev_down(struct net_device *dev)
 393 {
 394         if (dev->features & NETIF_F_HW_ESP)
 395                 xfrm_dev_state_flush(dev_net(dev), dev, true);
 396
 397         return NOTIFY_DONE;
 398 }
 399
 400 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
 401 {
 402         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 403
 404         switch (event) {
 405         case NETDEV_REGISTER:
 406                 return xfrm_dev_register(dev);
 407
 408         case NETDEV_FEAT_CHANGE:
 409                 return xfrm_dev_feat_change(dev);
 410
 411         case NETDEV_DOWN:
 412         case NETDEV_UNREGISTER:
 413                 return xfrm_dev_down(dev);
 414         }
 415         return NOTIFY_DONE;
 416 }
 417
 418 static struct notifier_block xfrm_dev_notifier = {
 419         .notifier_call  = xfrm_dev_event,
 420 };
 421
 422 void __init xfrm_dev_init(void)
 423 {
 424         register_netdevice_notifier(&xfrm_dev_notifier);
 425 }