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/ip.h>
  20 #include <net/xfrm.h>
  21 #include <net/esp.h>
  22 #include <linux/scatterlist.h>
  23 #include <linux/kernel.h>
  24 #include <linux/slab.h>
  25 #include <linux/spinlock.h>
  26 #include <net/ip6_route.h>
  27 #include <net/ipv6.h>
  28 #include <linux/icmpv6.h>
  29
  30 static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
  31 {
  32         int off = sizeof(struct ipv6hdr);
  33         struct ipv6_opt_hdr *exthdr;
  34
  35         if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP))
  36                 return offsetof(struct ipv6hdr, nexthdr);
  37
  38         while (off < nhlen) {
  39                 exthdr = (void *)ipv6_hdr + off;
  40                 if (exthdr->nexthdr == NEXTHDR_ESP)
  41                         return off;
  42
  43                 off += ipv6_optlen(exthdr);
  44         }
  45
  46         return 0;
  47 }
  48
  49 static struct sk_buff *esp6_gro_receive(struct list_head *head,
  50                                         struct sk_buff *skb)
  51 {
  52         int offset = skb_gro_offset(skb);
  53         struct xfrm_offload *xo;
  54         struct xfrm_state *x;
  55         __be32 seq;
  56         __be32 spi;
  57         int nhoff;
  58         int err;
  59
  60         if (!pskb_pull(skb, offset))
  61                 return NULL;
  62
  63         if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
  64                 goto out;
  65
  66         xo = xfrm_offload(skb);
  67         if (!xo || !(xo->flags & CRYPTO_DONE)) {
  68                 struct sec_path *sp = secpath_set(skb);
  69
  70                 if (!sp)
  71                         goto out;
  72
  73                 if (sp->len == XFRM_MAX_DEPTH)
  74                         goto out_reset;
  75
  76                 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
  77                                       (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
  78                                       spi, IPPROTO_ESP, AF_INET6);
  79                 if (!x)
  80                         goto out_reset;
  81
  82                 skb->mark = xfrm_smark_get(skb->mark, x);
  83
  84                 sp->xvec[sp->len++] = x;
  85                 sp->olen++;
  86
  87                 xo = xfrm_offload(skb);
  88                 if (!xo)
  89                         goto out_reset;
  90         }
  91
  92         xo->flags |= XFRM_GRO;
  93
  94         nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
  95         if (!nhoff)
  96                 goto out;
  97
  98         IP6CB(skb)->nhoff = nhoff;
  99         XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
 100         XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
 101         XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
 102         XFRM_SPI_SKB_CB(skb)->seq = seq;
 103
 104         /* We don't need to handle errors from xfrm_input, it does all
 105          * the error handling and frees the resources on error. */
 106         xfrm_input(skb, IPPROTO_ESP, spi, -2);
 107
 108         return ERR_PTR(-EINPROGRESS);
 109 out_reset:
 110         secpath_reset(skb);
 111 out:
 112         skb_push(skb, offset);
 113         NAPI_GRO_CB(skb)->same_flow = 0;
 114         NAPI_GRO_CB(skb)->flush = 1;
 115
 116         return NULL;
 117 }
 118
 119 static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
 120 {
 121         struct ip_esp_hdr *esph;
 122         struct ipv6hdr *iph = ipv6_hdr(skb);
 123         struct xfrm_offload *xo = xfrm_offload(skb);
 124         u8 proto = iph->nexthdr;
 125
 126         skb_push(skb, -skb_network_offset(skb));
 127
 128         if (x->outer_mode.encap == XFRM_MODE_TRANSPORT) {
 129                 __be16 frag;
 130
 131                 ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &proto, &frag);
 132         }
 133
 134         esph = ip_esp_hdr(skb);
 135         *skb_mac_header(skb) = IPPROTO_ESP;
 136
 137         esph->spi = x->id.spi;
 138         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 139
 140         xo->proto = proto;
 141 }
 142
 143 static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
 144                                                 struct sk_buff *skb,
 145                                                 netdev_features_t features)
 146 {
 147         __skb_push(skb, skb->mac_len);
 148         return skb_mac_gso_segment(skb, features);
 149 }
 150
 151 static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
 152                                                    struct sk_buff *skb,
 153                                                    netdev_features_t features)
 154 {
 155         const struct net_offload *ops;
 156         struct sk_buff *segs = ERR_PTR(-EINVAL);
 157         struct xfrm_offload *xo = xfrm_offload(skb);
 158
 159         skb->transport_header += x->props.header_len;
 160         ops = rcu_dereference(inet6_offloads[xo->proto]);
 161         if (likely(ops && ops->callbacks.gso_segment))
 162                 segs = ops->callbacks.gso_segment(skb, features);
 163
 164         return segs;
 165 }
 166
 167 static struct sk_buff *xfrm6_beet_gso_segment(struct xfrm_state *x,
 168                                               struct sk_buff *skb,
 169                                               netdev_features_t features)
 170 {
 171         struct xfrm_offload *xo = xfrm_offload(skb);
 172         struct sk_buff *segs = ERR_PTR(-EINVAL);
 173         const struct net_offload *ops;
 174         u8 proto = xo->proto;
 175
 176         skb->transport_header += x->props.header_len;
 177
 178         if (x->sel.family != AF_INET6) {
 179                 skb->transport_header -=
 180                         (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
 181
 182                 if (proto == IPPROTO_BEETPH) {
 183                         struct ip_beet_phdr *ph =
 184                                 (struct ip_beet_phdr *)skb->data;
 185
 186                         skb->transport_header += ph->hdrlen * 8;
 187                         proto = ph->nexthdr;
 188                 } else {
 189                         skb->transport_header -= IPV4_BEET_PHMAXLEN;
 190                 }
 191
 192                 if (proto == IPPROTO_TCP)
 193                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
 194         } else {
 195                 __be16 frag;
 196
 197                 skb->transport_header +=
 198                         ipv6_skip_exthdr(skb, 0, &proto, &frag);
 199         }
 200
 201         __skb_pull(skb, skb_transport_offset(skb));
 202         ops = rcu_dereference(inet6_offloads[proto]);
 203         if (likely(ops && ops->callbacks.gso_segment))
 204                 segs = ops->callbacks.gso_segment(skb, features);
 205
 206         return segs;
 207 }
 208
 209 static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
 210                                                     struct sk_buff *skb,
 211                                                     netdev_features_t features)
 212 {
 213         switch (x->outer_mode.encap) {
 214         case XFRM_MODE_TUNNEL:
 215                 return xfrm6_tunnel_gso_segment(x, skb, features);
 216         case XFRM_MODE_TRANSPORT:
 217                 return xfrm6_transport_gso_segment(x, skb, features);
 218         case XFRM_MODE_BEET:
 219                 return xfrm6_beet_gso_segment(x, skb, features);
 220         }
 221
 222         return ERR_PTR(-EOPNOTSUPP);
 223 }
 224
 225 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
 226                                         netdev_features_t features)
 227 {
 228         struct xfrm_state *x;
 229         struct ip_esp_hdr *esph;
 230         struct crypto_aead *aead;
 231         netdev_features_t esp_features = features;
 232         struct xfrm_offload *xo = xfrm_offload(skb);
 233         struct sec_path *sp;
 234
 235         if (!xo)
 236                 return ERR_PTR(-EINVAL);
 237
 238         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
 239                 return ERR_PTR(-EINVAL);
 240
 241         sp = skb_sec_path(skb);
 242         x = sp->xvec[sp->len - 1];
 243         aead = x->data;
 244         esph = ip_esp_hdr(skb);
 245
 246         if (esph->spi != x->id.spi)
 247                 return ERR_PTR(-EINVAL);
 248
 249         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 250                 return ERR_PTR(-EINVAL);
 251
 252         __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
 253
 254         skb->encap_hdr_csum = 1;
 255
 256         if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
 257                 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
 258         else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
 259                 esp_features = features & ~NETIF_F_CSUM_MASK;
 260
 261         xo->flags |= XFRM_GSO_SEGMENT;
 262
 263         return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
 264 }
 265
 266 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
 267 {
 268         struct crypto_aead *aead = x->data;
 269         struct xfrm_offload *xo = xfrm_offload(skb);
 270
 271         if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
 272                 return -EINVAL;
 273
 274         if (!(xo->flags & CRYPTO_DONE))
 275                 skb->ip_summed = CHECKSUM_NONE;
 276
 277         return esp6_input_done2(skb, 0);
 278 }
 279
 280 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
 281 {
 282         int len;
 283         int err;
 284         int alen;
 285         int blksize;
 286         struct xfrm_offload *xo;
 287         struct crypto_aead *aead;
 288         struct esp_info esp;
 289         bool hw_offload = true;
 290         __u32 seq;
 291
 292         esp.inplace = true;
 293
 294         xo = xfrm_offload(skb);
 295
 296         if (!xo)
 297                 return -EINVAL;
 298
 299         if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
 300                 xo->flags |= CRYPTO_FALLBACK;
 301                 hw_offload = false;
 302         }
 303
 304         esp.proto = xo->proto;
 305
 306         /* skb is pure payload to encrypt */
 307
 308         aead = x->data;
 309         alen = crypto_aead_authsize(aead);
 310
 311         esp.tfclen = 0;
 312         /* XXX: Add support for tfc padding here. */
 313
 314         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 315         esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
 316         esp.plen = esp.clen - skb->len - esp.tfclen;
 317         esp.tailen = esp.tfclen + esp.plen + alen;
 318
 319         if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
 320                 esp.nfrags = esp6_output_head(x, skb, &esp);
 321                 if (esp.nfrags < 0)
 322                         return esp.nfrags;
 323         }
 324
 325         seq = xo->seq.low;
 326
 327         esp.esph = ip_esp_hdr(skb);
 328         esp.esph->spi = x->id.spi;
 329
 330         skb_push(skb, -skb_network_offset(skb));
 331
 332         if (xo->flags & XFRM_GSO_SEGMENT) {
 333                 esp.esph->seq_no = htonl(seq);
 334
 335                 if (!skb_is_gso(skb))
 336                         xo->seq.low++;
 337                 else
 338                         xo->seq.low += skb_shinfo(skb)->gso_segs;
 339         }
 340
 341         esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
 342
 343         len = skb->len - sizeof(struct ipv6hdr);
 344         if (len > IPV6_MAXPLEN)
 345                 len = 0;
 346
 347         ipv6_hdr(skb)->payload_len = htons(len);
 348
 349         if (hw_offload)
 350                 return 0;
 351
 352         err = esp6_output_tail(x, skb, &esp);
 353         if (err)
 354                 return err;
 355
 356         secpath_reset(skb);
 357
 358         return 0;
 359 }
 360
 361 static const struct net_offload esp6_offload = {
 362         .callbacks = {
 363                 .gro_receive = esp6_gro_receive,
 364                 .gso_segment = esp6_gso_segment,
 365         },
 366 };
 367
 368 static const struct xfrm_type_offload esp6_type_offload = {
 369         .description    = "ESP6 OFFLOAD",
 370         .owner          = THIS_MODULE,
 371         .proto          = IPPROTO_ESP,
 372         .input_tail     = esp6_input_tail,
 373         .xmit           = esp6_xmit,
 374         .encap          = esp6_gso_encap,
 375 };
 376
 377 static int __init esp6_offload_init(void)
 378 {
 379         if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
 380                 pr_info("%s: can't add xfrm type offload\n", __func__);
 381                 return -EAGAIN;
 382         }
 383
 384         return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
 385 }
 386
 387 static void __exit esp6_offload_exit(void)
 388 {
 389         xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
 390         inet6_del_offload(&esp6_offload, IPPROTO_ESP);
 391 }
 392
 393 module_init(esp6_offload_init);
 394 module_exit(esp6_offload_exit);
 395 MODULE_LICENSE("GPL");
 396 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 397 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
 398 MODULE_DESCRIPTION("IPV6 GSO/GRO offload support");