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/gso.h>
  19 #include <net/xfrm.h>
  20 #include <linux/notifier.h>
  21
  22 #ifdef CONFIG_XFRM_OFFLOAD
  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
  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
  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 */
  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
 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
 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
 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                 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, 0, 0, saddr, daddr,
 275                                         x->props.family,
 276                                         xfrm_smark_get(0, x));
 277                 if (IS_ERR(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, &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, &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 }
 338 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
 339
 340 int 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, 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, &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, &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, &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 }
 401 EXPORT_SYMBOL_GPL(xfrm_dev_policy_add);
 402
 403 bool 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)
 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, 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
 426 ok:
 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 }
 432 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
 433
 434 void 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(txq))
 447                 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
 448         HARD_TX_UNLOCK(dev, txq);
 449
 450         if (!dev_xmit_complete(ret)) {
 451                 local_irq_save(flags);
 452                 sd = this_cpu_ptr(&softnet_data);
 453                 skb_queue_tail(&sd->xfrm_backlog, skb);
 454                 raise_softirq_irqoff(NET_TX_SOFTIRQ);
 455                 local_irq_restore(flags);
 456         }
 457         rcu_read_unlock();
 458 }
 459 EXPORT_SYMBOL_GPL(xfrm_dev_resume);
 460
 461 void 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(xfrm_backlog))
 468                 return;
 469
 470         __skb_queue_head_init(&list);
 471
 472         spin_lock(&xfrm_backlog->lock);
 473         skb_queue_splice_init(xfrm_backlog, &list);
 474         spin_unlock(&xfrm_backlog->lock);
 475
 476         while (!skb_queue_empty(&list)) {
 477                 skb = __skb_dequeue(&list);
 478                 xfrm_dev_resume(skb);
 479         }
 480
 481 }
 482 #endif
 483
 484 static 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
 504 static int xfrm_dev_down(struct net_device *dev)
 505 {
 506         if (dev->features & NETIF_F_HW_ESP) {
 507                 xfrm_dev_state_flush(dev_net(dev), dev, true);
 508                 xfrm_dev_policy_flush(dev_net(dev), dev, true);
 509         }
 510
 511         return NOTIFY_DONE;
 512 }
 513
 514 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
 515 {
 516         struct net_device *dev = netdev_notifier_info_to_dev(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
 532 static struct notifier_block xfrm_dev_notifier = {
 533         .notifier_call  = xfrm_dev_event,
 534 };
 535
 536 void __init xfrm_dev_init(void)
 537 {
 538         register_netdevice_notifier(&xfrm_dev_notifier);
 539 }