net/xfrm/xfrm_device.c

   1 /*
   2  * xfrm_device.c - IPsec device offloading code.
   3  *
   4  * Copyright (c) 2015 secunet Security Networks AG
   5  *
   6  * Author:
   7  * Steffen Klassert <steffen.klassert@secunet.com>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  */
  14
  15 #include <linux/errno.h>
  16 #include <linux/module.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/slab.h>
  20 #include <linux/spinlock.h>
  21 #include <net/dst.h>
  22 #include <net/xfrm.h>
  23 #include <linux/notifier.h>
  24
  25 #ifdef CONFIG_XFRM_OFFLOAD
  26 struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features, bool *again)
  27 {
  28         int err;
  29         unsigned long flags;
  30         struct xfrm_state *x;
  31         struct sk_buff *skb2;
  32         struct softnet_data *sd;
  33         netdev_features_t esp_features = features;
  34         struct xfrm_offload *xo = xfrm_offload(skb);
  35
  36         if (!xo)
  37                 return skb;
  38
  39         if (!(features & NETIF_F_HW_ESP))
  40                 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
  41
  42         x = skb->sp->xvec[skb->sp->len - 1];
  43         if (xo->flags & XFRM_GRO || x->xso.flags & XFRM_OFFLOAD_INBOUND)
  44                 return skb;
  45
  46         local_irq_save(flags);
  47         sd = this_cpu_ptr(&softnet_data);
  48         err = !skb_queue_empty(&sd->xfrm_backlog);
  49         local_irq_restore(flags);
  50
  51         if (err) {
  52                 *again = true;
  53                 return skb;
  54         }
  55
  56         if (skb_is_gso(skb)) {
  57                 struct net_device *dev = skb->dev;
  58
  59                 if (unlikely(x->xso.dev != dev)) {
  60                         struct sk_buff *segs;
  61
  62                         /* Packet got rerouted, fixup features and segment it. */
  63                         esp_features = esp_features & ~(NETIF_F_HW_ESP
  64                                                         | NETIF_F_GSO_ESP);
  65
  66                         segs = skb_gso_segment(skb, esp_features);
  67                         if (IS_ERR(segs)) {
  68                                 kfree_skb(skb);
  69                                 atomic_long_inc(&dev->tx_dropped);
  70                                 return NULL;
  71                         } else {
  72                                 consume_skb(skb);
  73                                 skb = segs;
  74                         }
  75                 }
  76         }
  77
  78         if (!skb->next) {
  79                 x->outer_mode->xmit(x, skb);
  80
  81                 xo->flags |= XFRM_DEV_RESUME;
  82
  83                 err = x->type_offload->xmit(x, skb, esp_features);
  84                 if (err) {
  85                         if (err == -EINPROGRESS)
  86                                 return NULL;
  87
  88                         XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
  89                         kfree_skb(skb);
  90                         return NULL;
  91                 }
  92
  93                 skb_push(skb, skb->data - skb_mac_header(skb));
  94
  95                 return skb;
  96         }
  97
  98         skb2 = skb;
  99
 100         do {
 101                 struct sk_buff *nskb = skb2->next;
 102                 skb2->next = NULL;
 103
 104                 xo = xfrm_offload(skb2);
 105                 xo->flags |= XFRM_DEV_RESUME;
 106
 107                 x->outer_mode->xmit(x, skb2);
 108
 109                 err = x->type_offload->xmit(x, skb2, esp_features);
 110                 if (!err) {
 111                         skb2->next = nskb;
 112                 } else if (err != -EINPROGRESS) {
 113                         XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
 114                         skb2->next = nskb;
 115                         kfree_skb_list(skb2);
 116                         return NULL;
 117                 } else {
 118                         if (skb == skb2)
 119                                 skb = nskb;
 120
 121                         if (!skb)
 122                                 return NULL;
 123
 124                         goto skip_push;
 125                 }
 126
 127                 skb_push(skb2, skb2->data - skb_mac_header(skb2));
 128
 129 skip_push:
 130                 skb2 = nskb;
 131         } while (skb2);
 132
 133         return skb;
 134 }
 135 EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
 136
 137 int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 138                        struct xfrm_user_offload *xuo)
 139 {
 140         int err;
 141         struct dst_entry *dst;
 142         struct net_device *dev;
 143         struct xfrm_state_offload *xso = &x->xso;
 144         xfrm_address_t *saddr;
 145         xfrm_address_t *daddr;
 146
 147         if (!x->type_offload)
 148                 return -EINVAL;
 149
 150         /* We don't yet support UDP encapsulation and TFC padding. */
 151         if (x->encap || x->tfcpad)
 152                 return -EINVAL;
 153
 154         dev = dev_get_by_index(net, xuo->ifindex);
 155         if (!dev) {
 156                 if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
 157                         saddr = &x->props.saddr;
 158                         daddr = &x->id.daddr;
 159                 } else {
 160                         saddr = &x->id.daddr;
 161                         daddr = &x->props.saddr;
 162                 }
 163
 164                 dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
 165                                         x->props.family,
 166                                         xfrm_smark_get(0, x));
 167                 if (IS_ERR(dst))
 168                         return 0;
 169
 170                 dev = dst->dev;
 171
 172                 dev_hold(dev);
 173                 dst_release(dst);
 174         }
 175
 176         if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
 177                 xso->dev = NULL;
 178                 dev_put(dev);
 179                 return 0;
 180         }
 181
 182         if (x->props.flags & XFRM_STATE_ESN &&
 183             !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
 184                 xso->dev = NULL;
 185                 dev_put(dev);
 186                 return -EINVAL;
 187         }
 188
 189         xso->dev = dev;
 190         xso->num_exthdrs = 1;
 191         xso->flags = xuo->flags;
 192
 193         err = dev->xfrmdev_ops->xdo_dev_state_add(x);
 194         if (err) {
 195                 xso->dev = NULL;
 196                 dev_put(dev);
 197                 return err;
 198         }
 199
 200         return 0;
 201 }
 202 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
 203
 204 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 205 {
 206         int mtu;
 207         struct dst_entry *dst = skb_dst(skb);
 208         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 209         struct net_device *dev = x->xso.dev;
 210
 211         if (!x->type_offload || x->encap)
 212                 return false;
 213
 214         if ((!dev || (dev == xfrm_dst_path(dst)->dev)) &&
 215             (!xdst->child->xfrm && x->type->get_mtu)) {
 216                 mtu = x->type->get_mtu(x, xdst->child_mtu_cached);
 217
 218                 if (skb->len <= mtu)
 219                         goto ok;
 220
 221                 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 222                         goto ok;
 223         }
 224
 225         return false;
 226
 227 ok:
 228         if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
 229                 return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
 230
 231         return true;
 232 }
 233 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
 234
 235 void xfrm_dev_resume(struct sk_buff *skb)
 236 {
 237         struct net_device *dev = skb->dev;
 238         int ret = NETDEV_TX_BUSY;
 239         struct netdev_queue *txq;
 240         struct softnet_data *sd;
 241         unsigned long flags;
 242
 243         rcu_read_lock();
 244         txq = netdev_pick_tx(dev, skb, NULL);
 245
 246         HARD_TX_LOCK(dev, txq, smp_processor_id());
 247         if (!netif_xmit_frozen_or_stopped(txq))
 248                 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
 249         HARD_TX_UNLOCK(dev, txq);
 250
 251         if (!dev_xmit_complete(ret)) {
 252                 local_irq_save(flags);
 253                 sd = this_cpu_ptr(&softnet_data);
 254                 skb_queue_tail(&sd->xfrm_backlog, skb);
 255                 raise_softirq_irqoff(NET_TX_SOFTIRQ);
 256                 local_irq_restore(flags);
 257         }
 258         rcu_read_unlock();
 259 }
 260 EXPORT_SYMBOL_GPL(xfrm_dev_resume);
 261
 262 void xfrm_dev_backlog(struct softnet_data *sd)
 263 {
 264         struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
 265         struct sk_buff_head list;
 266         struct sk_buff *skb;
 267
 268         if (skb_queue_empty(xfrm_backlog))
 269                 return;
 270
 271         __skb_queue_head_init(&list);
 272
 273         spin_lock(&xfrm_backlog->lock);
 274         skb_queue_splice_init(xfrm_backlog, &list);
 275         spin_unlock(&xfrm_backlog->lock);
 276
 277         while (!skb_queue_empty(&list)) {
 278                 skb = __skb_dequeue(&list);
 279                 xfrm_dev_resume(skb);
 280         }
 281
 282 }
 283 #endif
 284
 285 static int xfrm_api_check(struct net_device *dev)
 286 {
 287 #ifdef CONFIG_XFRM_OFFLOAD
 288         if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 289             !(dev->features & NETIF_F_HW_ESP))
 290                 return NOTIFY_BAD;
 291
 292         if ((dev->features & NETIF_F_HW_ESP) &&
 293             (!(dev->xfrmdev_ops &&
 294                dev->xfrmdev_ops->xdo_dev_state_add &&
 295                dev->xfrmdev_ops->xdo_dev_state_delete)))
 296                 return NOTIFY_BAD;
 297 #else
 298         if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
 299                 return NOTIFY_BAD;
 300 #endif
 301
 302         return NOTIFY_DONE;
 303 }
 304
 305 static int xfrm_dev_register(struct net_device *dev)
 306 {
 307         return xfrm_api_check(dev);
 308 }
 309
 310 static int xfrm_dev_feat_change(struct net_device *dev)
 311 {
 312         return xfrm_api_check(dev);
 313 }
 314
 315 static int xfrm_dev_down(struct net_device *dev)
 316 {
 317         if (dev->features & NETIF_F_HW_ESP)
 318                 xfrm_dev_state_flush(dev_net(dev), dev, true);
 319
 320         return NOTIFY_DONE;
 321 }
 322
 323 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
 324 {
 325         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 326
 327         switch (event) {
 328         case NETDEV_REGISTER:
 329                 return xfrm_dev_register(dev);
 330
 331         case NETDEV_FEAT_CHANGE:
 332                 return xfrm_dev_feat_change(dev);
 333
 334         case NETDEV_DOWN:
 335                 return xfrm_dev_down(dev);
 336         }
 337         return NOTIFY_DONE;
 338 }
 339
 340 static struct notifier_block xfrm_dev_notifier = {
 341         .notifier_call  = xfrm_dev_event,
 342 };
 343
 344 void __init xfrm_dev_init(void)
 345 {
 346         register_netdevice_notifier(&xfrm_dev_notifier);
 347 }