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