net/ipv6/esp6_offload.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * IPV6 GSO/GRO offload support
   4  * Linux INET implementation
   5  *
   6  * Copyright (C) 2016 secunet Security Networks AG
   7  * Author: Steffen Klassert <steffen.klassert@secunet.com>
   8  *
   9  * ESP GRO support
  10  */
  11
  12 #include <linux/skbuff.h>
  13 #include <linux/init.h>
  14 #include <net/protocol.h>
  15 #include <crypto/aead.h>
  16 #include <crypto/authenc.h>
  17 #include <linux/err.h>
  18 #include <linux/module.h>
  19 #include <net/gro.h>
  20 #include <net/gso.h>
  21 #include <net/ip.h>
  22 #include <net/xfrm.h>
  23 #include <net/esp.h>
  24 #include <linux/scatterlist.h>
  25 #include <linux/kernel.h>
  26 #include <linux/slab.h>
  27 #include <linux/spinlock.h>
  28 #include <net/ip6_route.h>
  29 #include <net/ipv6.h>
  30 #include <linux/icmpv6.h>
  31
  32 static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
  33 {
  34         int off = sizeof(struct ipv6hdr);
  35         struct ipv6_opt_hdr *exthdr;
  36
  37         /* ESP or ESPINUDP */
  38         if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP ||
  39                    ipv6_hdr->nexthdr == NEXTHDR_UDP))
  40                 return offsetof(struct ipv6hdr, nexthdr);
  41
  42         while (off < nhlen) {
  43                 exthdr = (void *)ipv6_hdr + off;
  44                 if (exthdr->nexthdr == NEXTHDR_ESP)
  45                         return off;
  46
  47                 off += ipv6_optlen(exthdr);
  48         }
  49
  50         return 0;
  51 }
  52
  53 static struct sk_buff *esp6_gro_receive(struct list_head *head,
  54                                         struct sk_buff *skb)
  55 {
  56         int offset = skb_gro_offset(skb);
  57         struct xfrm_offload *xo;
  58         struct xfrm_state *x;
  59         int encap_type = 0;
  60         __be32 seq;
  61         __be32 spi;
  62         int nhoff;
  63
  64         if (NAPI_GRO_CB(skb)->proto == IPPROTO_UDP)
  65                 encap_type = UDP_ENCAP_ESPINUDP;
  66
  67         if (!pskb_pull(skb, offset))
  68                 return NULL;
  69
  70         if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
  71                 goto out;
  72
  73         xo = xfrm_offload(skb);
  74         if (!xo || !(xo->flags & CRYPTO_DONE)) {
  75                 struct sec_path *sp = secpath_set(skb);
  76
  77                 if (!sp)
  78                         goto out;
  79
  80                 if (sp->len == XFRM_MAX_DEPTH)
  81                         goto out_reset;
  82
  83                 x = xfrm_input_state_lookup(dev_net(skb->dev), skb->mark,
  84                                             (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
  85                                             spi, IPPROTO_ESP, AF_INET6);
  86
  87                 if (unlikely(x && x->dir && x->dir != XFRM_SA_DIR_IN)) {
  88                         /* non-offload path will record the error and audit log */
  89                         xfrm_state_put(x);
  90                         x = NULL;
  91                 }
  92
  93                 if (!x)
  94                         goto out_reset;
  95
  96                 skb->mark = xfrm_smark_get(skb->mark, x);
  97
  98                 sp->xvec[sp->len++] = x;
  99                 sp->olen++;
 100
 101                 xo = xfrm_offload(skb);
 102                 if (!xo)
 103                         goto out_reset;
 104         }
 105
 106         xo->flags |= XFRM_GRO;
 107
 108         nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
 109         if (!nhoff)
 110                 goto out;
 111
 112         IP6CB(skb)->nhoff = nhoff;
 113         XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
 114         XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
 115         XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
 116         XFRM_SPI_SKB_CB(skb)->seq = seq;
 117
 118         /* We don't need to handle errors from xfrm_input, it does all
 119          * the error handling and frees the resources on error. */
 120         xfrm_input(skb, IPPROTO_ESP, spi, encap_type);
 121
 122         return ERR_PTR(-EINPROGRESS);
 123 out_reset:
 124         secpath_reset(skb);
 125 out:
 126         skb_push(skb, offset);
 127         NAPI_GRO_CB(skb)->same_flow = 0;
 128         NAPI_GRO_CB(skb)->flush = 1;
 129
 130         return NULL;
 131 }
 132
 133 static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
 134 {
 135         struct ip_esp_hdr *esph;
 136         struct ipv6hdr *iph = ipv6_hdr(skb);
 137         struct xfrm_offload *xo = xfrm_offload(skb);
 138         u8 proto = iph->nexthdr;
 139
 140         skb_push(skb, -skb_network_offset(skb));
 141
 142         if (x->outer_mode.encap == XFRM_MODE_TRANSPORT) {
 143                 __be16 frag;
 144
 145                 ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &proto, &frag);
 146         }
 147
 148         esph = ip_esp_hdr(skb);
 149         *skb_mac_header(skb) = IPPROTO_ESP;
 150
 151         esph->spi = x->id.spi;
 152         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 153
 154         xo->proto = proto;
 155 }
 156
 157 static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
 158                                                 struct sk_buff *skb,
 159                                                 netdev_features_t features)
 160 {
 161         __be16 type = x->inner_mode.family == AF_INET ? htons(ETH_P_IP)
 162                                                       : htons(ETH_P_IPV6);
 163
 164         return skb_eth_gso_segment(skb, features, type);
 165 }
 166
 167 static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
 168                                                    struct sk_buff *skb,
 169                                                    netdev_features_t features)
 170 {
 171         const struct net_offload *ops;
 172         struct sk_buff *segs = ERR_PTR(-EINVAL);
 173         struct xfrm_offload *xo = xfrm_offload(skb);
 174
 175         skb->transport_header += x->props.header_len;
 176         ops = rcu_dereference(inet6_offloads[xo->proto]);
 177         if (likely(ops && ops->callbacks.gso_segment))
 178                 segs = ops->callbacks.gso_segment(skb, features);
 179
 180         return segs;
 181 }
 182
 183 static struct sk_buff *xfrm6_beet_gso_segment(struct xfrm_state *x,
 184                                               struct sk_buff *skb,
 185                                               netdev_features_t features)
 186 {
 187         struct xfrm_offload *xo = xfrm_offload(skb);
 188         struct sk_buff *segs = ERR_PTR(-EINVAL);
 189         const struct net_offload *ops;
 190         u8 proto = xo->proto;
 191
 192         skb->transport_header += x->props.header_len;
 193
 194         if (x->sel.family != AF_INET6) {
 195                 skb->transport_header -=
 196                         (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
 197
 198                 if (proto == IPPROTO_BEETPH) {
 199                         struct ip_beet_phdr *ph =
 200                                 (struct ip_beet_phdr *)skb->data;
 201
 202                         skb->transport_header += ph->hdrlen * 8;
 203                         proto = ph->nexthdr;
 204                 } else {
 205                         skb->transport_header -= IPV4_BEET_PHMAXLEN;
 206                 }
 207
 208                 if (proto == IPPROTO_TCP)
 209                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
 210         } else {
 211                 __be16 frag;
 212
 213                 skb->transport_header +=
 214                         ipv6_skip_exthdr(skb, 0, &proto, &frag);
 215         }
 216
 217         if (proto == IPPROTO_IPIP)
 218                 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 219
 220         __skb_pull(skb, skb_transport_offset(skb));
 221         ops = rcu_dereference(inet6_offloads[proto]);
 222         if (likely(ops && ops->callbacks.gso_segment))
 223                 segs = ops->callbacks.gso_segment(skb, features);
 224
 225         return segs;
 226 }
 227
 228 static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
 229                                                     struct sk_buff *skb,
 230                                                     netdev_features_t features)
 231 {
 232         switch (x->outer_mode.encap) {
 233         case XFRM_MODE_TUNNEL:
 234                 return xfrm6_tunnel_gso_segment(x, skb, features);
 235         case XFRM_MODE_TRANSPORT:
 236                 return xfrm6_transport_gso_segment(x, skb, features);
 237         case XFRM_MODE_BEET:
 238                 return xfrm6_beet_gso_segment(x, skb, features);
 239         }
 240
 241         return ERR_PTR(-EOPNOTSUPP);
 242 }
 243
 244 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
 245                                         netdev_features_t features)
 246 {
 247         struct xfrm_state *x;
 248         struct ip_esp_hdr *esph;
 249         struct crypto_aead *aead;
 250         netdev_features_t esp_features = features;
 251         struct xfrm_offload *xo = xfrm_offload(skb);
 252         struct sec_path *sp;
 253
 254         if (!xo)
 255                 return ERR_PTR(-EINVAL);
 256
 257         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
 258                 return ERR_PTR(-EINVAL);
 259
 260         sp = skb_sec_path(skb);
 261         x = sp->xvec[sp->len - 1];
 262         aead = x->data;
 263         esph = ip_esp_hdr(skb);
 264
 265         if (esph->spi != x->id.spi)
 266                 return ERR_PTR(-EINVAL);
 267
 268         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 269                 return ERR_PTR(-EINVAL);
 270
 271         __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
 272
 273         skb->encap_hdr_csum = 1;
 274
 275         if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
 276                 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
 277                                             NETIF_F_SCTP_CRC);
 278         else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
 279                 esp_features = features & ~(NETIF_F_CSUM_MASK |
 280                                             NETIF_F_SCTP_CRC);
 281
 282         xo->flags |= XFRM_GSO_SEGMENT;
 283
 284         return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
 285 }
 286
 287 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
 288 {
 289         struct crypto_aead *aead = x->data;
 290         struct xfrm_offload *xo = xfrm_offload(skb);
 291
 292         if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
 293                 return -EINVAL;
 294
 295         if (!(xo->flags & CRYPTO_DONE))
 296                 skb->ip_summed = CHECKSUM_NONE;
 297
 298         return esp6_input_done2(skb, 0);
 299 }
 300
 301 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
 302 {
 303         int len;
 304         int err;
 305         int alen;
 306         int blksize;
 307         struct xfrm_offload *xo;
 308         struct crypto_aead *aead;
 309         struct esp_info esp;
 310         bool hw_offload = true;
 311         __u32 seq;
 312
 313         esp.inplace = true;
 314
 315         xo = xfrm_offload(skb);
 316
 317         if (!xo)
 318                 return -EINVAL;
 319
 320         if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
 321                 xo->flags |= CRYPTO_FALLBACK;
 322                 hw_offload = false;
 323         }
 324
 325         esp.proto = xo->proto;
 326
 327         /* skb is pure payload to encrypt */
 328
 329         aead = x->data;
 330         alen = crypto_aead_authsize(aead);
 331
 332         esp.tfclen = 0;
 333         /* XXX: Add support for tfc padding here. */
 334
 335         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 336         esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
 337         esp.plen = esp.clen - skb->len - esp.tfclen;
 338         esp.tailen = esp.tfclen + esp.plen + alen;
 339
 340         if (!hw_offload || !skb_is_gso(skb)) {
 341                 esp.nfrags = esp6_output_head(x, skb, &esp);
 342                 if (esp.nfrags < 0)
 343                         return esp.nfrags;
 344         }
 345
 346         seq = xo->seq.low;
 347
 348         esp.esph = ip_esp_hdr(skb);
 349         esp.esph->spi = x->id.spi;
 350
 351         skb_push(skb, -skb_network_offset(skb));
 352
 353         if (xo->flags & XFRM_GSO_SEGMENT) {
 354                 esp.esph->seq_no = htonl(seq);
 355
 356                 if (!skb_is_gso(skb))
 357                         xo->seq.low++;
 358                 else
 359                         xo->seq.low += skb_shinfo(skb)->gso_segs;
 360         }
 361
 362         if (xo->seq.low < seq)
 363                 xo->seq.hi++;
 364
 365         esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
 366
 367         len = skb->len - sizeof(struct ipv6hdr);
 368         if (len > IPV6_MAXPLEN)
 369                 len = 0;
 370
 371         ipv6_hdr(skb)->payload_len = htons(len);
 372
 373         if (hw_offload) {
 374                 if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
 375                         return -ENOMEM;
 376
 377                 xo = xfrm_offload(skb);
 378                 if (!xo)
 379                         return -EINVAL;
 380
 381                 xo->flags |= XFRM_XMIT;
 382                 return 0;
 383         }
 384
 385         err = esp6_output_tail(x, skb, &esp);
 386         if (err)
 387                 return err;
 388
 389         secpath_reset(skb);
 390
 391         if (skb_needs_linearize(skb, skb->dev->features) &&
 392             __skb_linearize(skb))
 393                 return -ENOMEM;
 394         return 0;
 395 }
 396
 397 static const struct net_offload esp6_offload = {
 398         .callbacks = {
 399                 .gro_receive = esp6_gro_receive,
 400                 .gso_segment = esp6_gso_segment,
 401         },
 402 };
 403
 404 static const struct xfrm_type_offload esp6_type_offload = {
 405         .owner          = THIS_MODULE,
 406         .proto          = IPPROTO_ESP,
 407         .input_tail     = esp6_input_tail,
 408         .xmit           = esp6_xmit,
 409         .encap          = esp6_gso_encap,
 410 };
 411
 412 static int __init esp6_offload_init(void)
 413 {
 414         if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
 415                 pr_info("%s: can't add xfrm type offload\n", __func__);
 416                 return -EAGAIN;
 417         }
 418
 419         return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
 420 }
 421
 422 static void __exit esp6_offload_exit(void)
 423 {
 424         xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
 425         inet6_del_offload(&esp6_offload, IPPROTO_ESP);
 426 }
 427
 428 module_init(esp6_offload_init);
 429 module_exit(esp6_offload_exit);
 430 MODULE_LICENSE("GPL");
 431 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 432 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
 433 MODULE_DESCRIPTION("IPV6 GSO/GRO offload support");