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_outer_mode_gso_segment(struct xfrm_state *x,
 163                                                     struct sk_buff *skb,
 164                                                     netdev_features_t features)
 165 {
 166         switch (x->outer_mode.encap) {
 167         case XFRM_MODE_TUNNEL:
 168                 return xfrm6_tunnel_gso_segment(x, skb, features);
 169         case XFRM_MODE_TRANSPORT:
 170                 return xfrm6_transport_gso_segment(x, skb, features);
 171         }
 172
 173         return ERR_PTR(-EOPNOTSUPP);
 174 }
 175
 176 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
 177                                         netdev_features_t features)
 178 {
 179         struct xfrm_state *x;
 180         struct ip_esp_hdr *esph;
 181         struct crypto_aead *aead;
 182         netdev_features_t esp_features = features;
 183         struct xfrm_offload *xo = xfrm_offload(skb);
 184         struct sec_path *sp;
 185
 186         if (!xo)
 187                 return ERR_PTR(-EINVAL);
 188
 189         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
 190                 return ERR_PTR(-EINVAL);
 191
 192         sp = skb_sec_path(skb);
 193         x = sp->xvec[sp->len - 1];
 194         aead = x->data;
 195         esph = ip_esp_hdr(skb);
 196
 197         if (esph->spi != x->id.spi)
 198                 return ERR_PTR(-EINVAL);
 199
 200         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 201                 return ERR_PTR(-EINVAL);
 202
 203         __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
 204
 205         skb->encap_hdr_csum = 1;
 206
 207         if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
 208                 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
 209         else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
 210                 esp_features = features & ~NETIF_F_CSUM_MASK;
 211
 212         xo->flags |= XFRM_GSO_SEGMENT;
 213
 214         return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
 215 }
 216
 217 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
 218 {
 219         struct crypto_aead *aead = x->data;
 220         struct xfrm_offload *xo = xfrm_offload(skb);
 221
 222         if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
 223                 return -EINVAL;
 224
 225         if (!(xo->flags & CRYPTO_DONE))
 226                 skb->ip_summed = CHECKSUM_NONE;
 227
 228         return esp6_input_done2(skb, 0);
 229 }
 230
 231 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
 232 {
 233         int len;
 234         int err;
 235         int alen;
 236         int blksize;
 237         struct xfrm_offload *xo;
 238         struct ip_esp_hdr *esph;
 239         struct crypto_aead *aead;
 240         struct esp_info esp;
 241         bool hw_offload = true;
 242         __u32 seq;
 243
 244         esp.inplace = true;
 245
 246         xo = xfrm_offload(skb);
 247
 248         if (!xo)
 249                 return -EINVAL;
 250
 251         if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
 252                 xo->flags |= CRYPTO_FALLBACK;
 253                 hw_offload = false;
 254         }
 255
 256         esp.proto = xo->proto;
 257
 258         /* skb is pure payload to encrypt */
 259
 260         aead = x->data;
 261         alen = crypto_aead_authsize(aead);
 262
 263         esp.tfclen = 0;
 264         /* XXX: Add support for tfc padding here. */
 265
 266         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 267         esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
 268         esp.plen = esp.clen - skb->len - esp.tfclen;
 269         esp.tailen = esp.tfclen + esp.plen + alen;
 270
 271         if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
 272                 esp.nfrags = esp6_output_head(x, skb, &esp);
 273                 if (esp.nfrags < 0)
 274                         return esp.nfrags;
 275         }
 276
 277         seq = xo->seq.low;
 278
 279         esph = ip_esp_hdr(skb);
 280         esph->spi = x->id.spi;
 281
 282         skb_push(skb, -skb_network_offset(skb));
 283
 284         if (xo->flags & XFRM_GSO_SEGMENT) {
 285                 esph->seq_no = htonl(seq);
 286
 287                 if (!skb_is_gso(skb))
 288                         xo->seq.low++;
 289                 else
 290                         xo->seq.low += skb_shinfo(skb)->gso_segs;
 291         }
 292
 293         esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
 294
 295         len = skb->len - sizeof(struct ipv6hdr);
 296         if (len > IPV6_MAXPLEN)
 297                 len = 0;
 298
 299         ipv6_hdr(skb)->payload_len = htons(len);
 300
 301         if (hw_offload)
 302                 return 0;
 303
 304         err = esp6_output_tail(x, skb, &esp);
 305         if (err)
 306                 return err;
 307
 308         secpath_reset(skb);
 309
 310         return 0;
 311 }
 312
 313 static const struct net_offload esp6_offload = {
 314         .callbacks = {
 315                 .gro_receive = esp6_gro_receive,
 316                 .gso_segment = esp6_gso_segment,
 317         },
 318 };
 319
 320 static const struct xfrm_type_offload esp6_type_offload = {
 321         .description    = "ESP6 OFFLOAD",
 322         .owner          = THIS_MODULE,
 323         .proto          = IPPROTO_ESP,
 324         .input_tail     = esp6_input_tail,
 325         .xmit           = esp6_xmit,
 326         .encap          = esp6_gso_encap,
 327 };
 328
 329 static int __init esp6_offload_init(void)
 330 {
 331         if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
 332                 pr_info("%s: can't add xfrm type offload\n", __func__);
 333                 return -EAGAIN;
 334         }
 335
 336         return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
 337 }
 338
 339 static void __exit esp6_offload_exit(void)
 340 {
 341         xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
 342         inet6_del_offload(&esp6_offload, IPPROTO_ESP);
 343 }
 344
 345 module_init(esp6_offload_init);
 346 module_exit(esp6_offload_exit);
 347 MODULE_LICENSE("GPL");
 348 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 349 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);