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                 sp->xvec[sp->len++] = x;
  83                 sp->olen++;
  84
  85                 xo = xfrm_offload(skb);
  86                 if (!xo) {
  87                         xfrm_state_put(x);
  88                         goto out_reset;
  89                 }
  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         int proto = iph->nexthdr;
 125
 126         skb_push(skb, -skb_network_offset(skb));
 127         esph = ip_esp_hdr(skb);
 128         *skb_mac_header(skb) = IPPROTO_ESP;
 129
 130         esph->spi = x->id.spi;
 131         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 132
 133         xo->proto = proto;
 134 }
 135
 136 static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
 137                                                 struct sk_buff *skb,
 138                                                 netdev_features_t features)
 139 {
 140         __skb_push(skb, skb->mac_len);
 141         return skb_mac_gso_segment(skb, features);
 142 }
 143
 144 static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
 145                                                    struct sk_buff *skb,
 146                                                    netdev_features_t features)
 147 {
 148         const struct net_offload *ops;
 149         struct sk_buff *segs = ERR_PTR(-EINVAL);
 150         struct xfrm_offload *xo = xfrm_offload(skb);
 151
 152         skb->transport_header += x->props.header_len;
 153         ops = rcu_dereference(inet6_offloads[xo->proto]);
 154         if (likely(ops && ops->callbacks.gso_segment))
 155                 segs = ops->callbacks.gso_segment(skb, features);
 156
 157         return segs;
 158 }
 159
 160 static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
 161                                                     struct sk_buff *skb,
 162                                                     netdev_features_t features)
 163 {
 164         switch (x->outer_mode.encap) {
 165         case XFRM_MODE_TUNNEL:
 166                 return xfrm6_tunnel_gso_segment(x, skb, features);
 167         case XFRM_MODE_TRANSPORT:
 168                 return xfrm6_transport_gso_segment(x, skb, features);
 169         }
 170
 171         return ERR_PTR(-EOPNOTSUPP);
 172 }
 173
 174 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
 175                                         netdev_features_t features)
 176 {
 177         struct xfrm_state *x;
 178         struct ip_esp_hdr *esph;
 179         struct crypto_aead *aead;
 180         netdev_features_t esp_features = features;
 181         struct xfrm_offload *xo = xfrm_offload(skb);
 182         struct sec_path *sp;
 183
 184         if (!xo)
 185                 return ERR_PTR(-EINVAL);
 186
 187         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
 188                 return ERR_PTR(-EINVAL);
 189
 190         sp = skb_sec_path(skb);
 191         x = sp->xvec[sp->len - 1];
 192         aead = x->data;
 193         esph = ip_esp_hdr(skb);
 194
 195         if (esph->spi != x->id.spi)
 196                 return ERR_PTR(-EINVAL);
 197
 198         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 199                 return ERR_PTR(-EINVAL);
 200
 201         __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
 202
 203         skb->encap_hdr_csum = 1;
 204
 205         if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
 206                 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
 207         else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
 208                 esp_features = features & ~NETIF_F_CSUM_MASK;
 209
 210         xo->flags |= XFRM_GSO_SEGMENT;
 211
 212         return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
 213 }
 214
 215 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
 216 {
 217         struct crypto_aead *aead = x->data;
 218         struct xfrm_offload *xo = xfrm_offload(skb);
 219
 220         if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
 221                 return -EINVAL;
 222
 223         if (!(xo->flags & CRYPTO_DONE))
 224                 skb->ip_summed = CHECKSUM_NONE;
 225
 226         return esp6_input_done2(skb, 0);
 227 }
 228
 229 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
 230 {
 231         int len;
 232         int err;
 233         int alen;
 234         int blksize;
 235         struct xfrm_offload *xo;
 236         struct ip_esp_hdr *esph;
 237         struct crypto_aead *aead;
 238         struct esp_info esp;
 239         bool hw_offload = true;
 240         __u32 seq;
 241
 242         esp.inplace = true;
 243
 244         xo = xfrm_offload(skb);
 245
 246         if (!xo)
 247                 return -EINVAL;
 248
 249         if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
 250                 xo->flags |= CRYPTO_FALLBACK;
 251                 hw_offload = false;
 252         }
 253
 254         esp.proto = xo->proto;
 255
 256         /* skb is pure payload to encrypt */
 257
 258         aead = x->data;
 259         alen = crypto_aead_authsize(aead);
 260
 261         esp.tfclen = 0;
 262         /* XXX: Add support for tfc padding here. */
 263
 264         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 265         esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
 266         esp.plen = esp.clen - skb->len - esp.tfclen;
 267         esp.tailen = esp.tfclen + esp.plen + alen;
 268
 269         if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
 270                 esp.nfrags = esp6_output_head(x, skb, &esp);
 271                 if (esp.nfrags < 0)
 272                         return esp.nfrags;
 273         }
 274
 275         seq = xo->seq.low;
 276
 277         esph = ip_esp_hdr(skb);
 278         esph->spi = x->id.spi;
 279
 280         skb_push(skb, -skb_network_offset(skb));
 281
 282         if (xo->flags & XFRM_GSO_SEGMENT) {
 283                 esph->seq_no = htonl(seq);
 284
 285                 if (!skb_is_gso(skb))
 286                         xo->seq.low++;
 287                 else
 288                         xo->seq.low += skb_shinfo(skb)->gso_segs;
 289         }
 290
 291         esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
 292
 293         len = skb->len - sizeof(struct ipv6hdr);
 294         if (len > IPV6_MAXPLEN)
 295                 len = 0;
 296
 297         ipv6_hdr(skb)->payload_len = htons(len);
 298
 299         if (hw_offload)
 300                 return 0;
 301
 302         err = esp6_output_tail(x, skb, &esp);
 303         if (err)
 304                 return err;
 305
 306         secpath_reset(skb);
 307
 308         return 0;
 309 }
 310
 311 static const struct net_offload esp6_offload = {
 312         .callbacks = {
 313                 .gro_receive = esp6_gro_receive,
 314                 .gso_segment = esp6_gso_segment,
 315         },
 316 };
 317
 318 static const struct xfrm_type_offload esp6_type_offload = {
 319         .description    = "ESP6 OFFLOAD",
 320         .owner          = THIS_MODULE,
 321         .proto          = IPPROTO_ESP,
 322         .input_tail     = esp6_input_tail,
 323         .xmit           = esp6_xmit,
 324         .encap          = esp6_gso_encap,
 325 };
 326
 327 static int __init esp6_offload_init(void)
 328 {
 329         if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
 330                 pr_info("%s: can't add xfrm type offload\n", __func__);
 331                 return -EAGAIN;
 332         }
 333
 334         return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
 335 }
 336
 337 static void __exit esp6_offload_exit(void)
 338 {
 339         xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
 340         inet6_del_offload(&esp6_offload, IPPROTO_ESP);
 341 }
 342
 343 module_init(esp6_offload_init);
 344 module_exit(esp6_offload_exit);
 345 MODULE_LICENSE("GPL");
 346 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 347 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);