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 skb_mark_not_on_list(skb2); 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->num_exthdrs = 0; 196 xso->flags = 0; 197 xso->dev = NULL; 198 dev_put(dev); 199 200 if (err != -EOPNOTSUPP) 201 return err; 202 } 203 204 return 0; 205 } 206 EXPORT_SYMBOL_GPL(xfrm_dev_state_add); 207 208 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x) 209 { 210 int mtu; 211 struct dst_entry *dst = skb_dst(skb); 212 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 213 struct net_device *dev = x->xso.dev; 214 215 if (!x->type_offload || x->encap) 216 return false; 217 218 if ((!dev || (dev == xfrm_dst_path(dst)->dev)) && 219 (!xdst->child->xfrm && x->type->get_mtu)) { 220 mtu = x->type->get_mtu(x, xdst->child_mtu_cached); 221 222 if (skb->len <= mtu) 223 goto ok; 224 225 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu)) 226 goto ok; 227 } 228 229 return false; 230 231 ok: 232 if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok) 233 return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x); 234 235 return true; 236 } 237 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok); 238 239 void xfrm_dev_resume(struct sk_buff *skb) 240 { 241 struct net_device *dev = skb->dev; 242 int ret = NETDEV_TX_BUSY; 243 struct netdev_queue *txq; 244 struct softnet_data *sd; 245 unsigned long flags; 246 247 rcu_read_lock(); 248 txq = netdev_pick_tx(dev, skb, NULL); 249 250 HARD_TX_LOCK(dev, txq, smp_processor_id()); 251 if (!netif_xmit_frozen_or_stopped(txq)) 252 skb = dev_hard_start_xmit(skb, dev, txq, &ret); 253 HARD_TX_UNLOCK(dev, txq); 254 255 if (!dev_xmit_complete(ret)) { 256 local_irq_save(flags); 257 sd = this_cpu_ptr(&softnet_data); 258 skb_queue_tail(&sd->xfrm_backlog, skb); 259 raise_softirq_irqoff(NET_TX_SOFTIRQ); 260 local_irq_restore(flags); 261 } 262 rcu_read_unlock(); 263 } 264 EXPORT_SYMBOL_GPL(xfrm_dev_resume); 265 266 void xfrm_dev_backlog(struct softnet_data *sd) 267 { 268 struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog; 269 struct sk_buff_head list; 270 struct sk_buff *skb; 271 272 if (skb_queue_empty(xfrm_backlog)) 273 return; 274 275 __skb_queue_head_init(&list); 276 277 spin_lock(&xfrm_backlog->lock); 278 skb_queue_splice_init(xfrm_backlog, &list); 279 spin_unlock(&xfrm_backlog->lock); 280 281 while (!skb_queue_empty(&list)) { 282 skb = __skb_dequeue(&list); 283 xfrm_dev_resume(skb); 284 } 285 286 } 287 #endif 288 289 static int xfrm_api_check(struct net_device *dev) 290 { 291 #ifdef CONFIG_XFRM_OFFLOAD 292 if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) && 293 !(dev->features & NETIF_F_HW_ESP)) 294 return NOTIFY_BAD; 295 296 if ((dev->features & NETIF_F_HW_ESP) && 297 (!(dev->xfrmdev_ops && 298 dev->xfrmdev_ops->xdo_dev_state_add && 299 dev->xfrmdev_ops->xdo_dev_state_delete))) 300 return NOTIFY_BAD; 301 #else 302 if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM)) 303 return NOTIFY_BAD; 304 #endif 305 306 return NOTIFY_DONE; 307 } 308 309 static int xfrm_dev_register(struct net_device *dev) 310 { 311 return xfrm_api_check(dev); 312 } 313 314 static int xfrm_dev_feat_change(struct net_device *dev) 315 { 316 return xfrm_api_check(dev); 317 } 318 319 static int xfrm_dev_down(struct net_device *dev) 320 { 321 if (dev->features & NETIF_F_HW_ESP) 322 xfrm_dev_state_flush(dev_net(dev), dev, true); 323 324 return NOTIFY_DONE; 325 } 326 327 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr) 328 { 329 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 330 331 switch (event) { 332 case NETDEV_REGISTER: 333 return xfrm_dev_register(dev); 334 335 case NETDEV_FEAT_CHANGE: 336 return xfrm_dev_feat_change(dev); 337 338 case NETDEV_DOWN: 339 return xfrm_dev_down(dev); 340 } 341 return NOTIFY_DONE; 342 } 343 344 static struct notifier_block xfrm_dev_notifier = { 345 .notifier_call = xfrm_dev_event, 346 }; 347 348 void __init xfrm_dev_init(void) 349 { 350 register_netdevice_notifier(&xfrm_dev_notifier); 351 } 352