net/ipv6/esp6_offload.c

   1 /*
   2  * IPV6 GSO/GRO offload support
   3  * Linux INET implementation
   4  *
   5  * Copyright (C) 2016 secunet Security Networks AG
   6  * Author: Steffen Klassert <steffen.klassert@secunet.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * ESP GRO support
  13  */
  14
  15 #include <linux/skbuff.h>
  16 #include <linux/init.h>
  17 #include <net/protocol.h>
  18 #include <crypto/aead.h>
  19 #include <crypto/authenc.h>
  20 #include <linux/err.h>
  21 #include <linux/module.h>
  22 #include <net/ip.h>
  23 #include <net/xfrm.h>
  24 #include <net/esp.h>
  25 #include <linux/scatterlist.h>
  26 #include <linux/kernel.h>
  27 #include <linux/slab.h>
  28 #include <linux/spinlock.h>
  29 #include <net/ip6_route.h>
  30 #include <net/ipv6.h>
  31 #include <linux/icmpv6.h>
  32
  33 static struct sk_buff **esp6_gro_receive(struct sk_buff **head,
  34                                          struct sk_buff *skb)
  35 {
  36         int offset = skb_gro_offset(skb);
  37         struct xfrm_offload *xo;
  38         struct xfrm_state *x;
  39         __be32 seq;
  40         __be32 spi;
  41         int err;
  42
  43         skb_pull(skb, offset);
  44
  45         if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
  46                 goto out;
  47
  48         xo = xfrm_offload(skb);
  49         if (!xo || !(xo->flags & CRYPTO_DONE)) {
  50                 err = secpath_set(skb);
  51                 if (err)
  52                         goto out;
  53
  54                 if (skb->sp->len == XFRM_MAX_DEPTH)
  55                         goto out;
  56
  57                 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
  58                                       (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
  59                                       spi, IPPROTO_ESP, AF_INET6);
  60                 if (!x)
  61                         goto out;
  62
  63                 skb->sp->xvec[skb->sp->len++] = x;
  64                 skb->sp->olen++;
  65
  66                 xo = xfrm_offload(skb);
  67                 if (!xo) {
  68                         xfrm_state_put(x);
  69                         goto out;
  70                 }
  71         }
  72
  73         xo->flags |= XFRM_GRO;
  74
  75         XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
  76         XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
  77         XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
  78         XFRM_SPI_SKB_CB(skb)->seq = seq;
  79
  80         /* We don't need to handle errors from xfrm_input, it does all
  81          * the error handling and frees the resources on error. */
  82         xfrm_input(skb, IPPROTO_ESP, spi, -2);
  83
  84         return ERR_PTR(-EINPROGRESS);
  85 out:
  86         skb_push(skb, offset);
  87         NAPI_GRO_CB(skb)->same_flow = 0;
  88         NAPI_GRO_CB(skb)->flush = 1;
  89
  90         return NULL;
  91 }
  92
  93 static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
  94 {
  95         struct ip_esp_hdr *esph;
  96         struct ipv6hdr *iph = ipv6_hdr(skb);
  97         struct xfrm_offload *xo = xfrm_offload(skb);
  98         int proto = iph->nexthdr;
  99
 100         skb_push(skb, -skb_network_offset(skb));
 101         esph = ip_esp_hdr(skb);
 102         *skb_mac_header(skb) = IPPROTO_ESP;
 103
 104         esph->spi = x->id.spi;
 105         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 106
 107         xo->proto = proto;
 108 }
 109
 110 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
 111                                         netdev_features_t features)
 112 {
 113         __u32 seq;
 114         int err = 0;
 115         struct sk_buff *skb2;
 116         struct xfrm_state *x;
 117         struct ip_esp_hdr *esph;
 118         struct crypto_aead *aead;
 119         struct sk_buff *segs = ERR_PTR(-EINVAL);
 120         netdev_features_t esp_features = features;
 121         struct xfrm_offload *xo = xfrm_offload(skb);
 122
 123         if (!xo)
 124                 goto out;
 125
 126         seq = xo->seq.low;
 127
 128         x = skb->sp->xvec[skb->sp->len - 1];
 129         aead = x->data;
 130         esph = ip_esp_hdr(skb);
 131
 132         if (esph->spi != x->id.spi)
 133                 goto out;
 134
 135         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 136                 goto out;
 137
 138         __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
 139
 140         skb->encap_hdr_csum = 1;
 141
 142         if (!(features & NETIF_F_HW_ESP))
 143                 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
 144
 145         segs = x->outer_mode->gso_segment(x, skb, esp_features);
 146         if (IS_ERR_OR_NULL(segs))
 147                 goto out;
 148
 149         __skb_pull(skb, skb->data - skb_mac_header(skb));
 150
 151         skb2 = segs;
 152         do {
 153                 struct sk_buff *nskb = skb2->next;
 154
 155                 xo = xfrm_offload(skb2);
 156                 xo->flags |= XFRM_GSO_SEGMENT;
 157                 xo->seq.low = seq;
 158                 xo->seq.hi = xfrm_replay_seqhi(x, seq);
 159
 160                 if(!(features & NETIF_F_HW_ESP))
 161                         xo->flags |= CRYPTO_FALLBACK;
 162
 163                 x->outer_mode->xmit(x, skb2);
 164
 165                 err = x->type_offload->xmit(x, skb2, esp_features);
 166                 if (err) {
 167                         kfree_skb_list(segs);
 168                         return ERR_PTR(err);
 169                 }
 170
 171                 if (!skb_is_gso(skb2))
 172                         seq++;
 173                 else
 174                         seq += skb_shinfo(skb2)->gso_segs;
 175
 176                 skb_push(skb2, skb2->mac_len);
 177                 skb2 = nskb;
 178         } while (skb2);
 179
 180 out:
 181         return segs;
 182 }
 183
 184 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
 185 {
 186         struct crypto_aead *aead = x->data;
 187
 188         if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
 189                 return -EINVAL;
 190
 191         skb->ip_summed = CHECKSUM_NONE;
 192
 193         return esp6_input_done2(skb, 0);
 194 }
 195
 196 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
 197 {
 198         int err;
 199         int alen;
 200         int blksize;
 201         struct xfrm_offload *xo;
 202         struct ip_esp_hdr *esph;
 203         struct crypto_aead *aead;
 204         struct esp_info esp;
 205         bool hw_offload = true;
 206
 207         esp.inplace = true;
 208
 209         xo = xfrm_offload(skb);
 210
 211         if (!xo)
 212                 return -EINVAL;
 213
 214         if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle ||
 215             (x->xso.dev != skb->dev)) {
 216                 xo->flags |= CRYPTO_FALLBACK;
 217                 hw_offload = false;
 218         }
 219
 220         esp.proto = xo->proto;
 221
 222         /* skb is pure payload to encrypt */
 223
 224         aead = x->data;
 225         alen = crypto_aead_authsize(aead);
 226
 227         esp.tfclen = 0;
 228         /* XXX: Add support for tfc padding here. */
 229
 230         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 231         esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
 232         esp.plen = esp.clen - skb->len - esp.tfclen;
 233         esp.tailen = esp.tfclen + esp.plen + alen;
 234
 235         if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
 236                 esp.nfrags = esp6_output_head(x, skb, &esp);
 237                 if (esp.nfrags < 0)
 238                         return esp.nfrags;
 239         }
 240
 241         esph = ip_esp_hdr(skb);
 242         esph->spi = x->id.spi;
 243
 244         skb_push(skb, -skb_network_offset(skb));
 245
 246         if (xo->flags & XFRM_GSO_SEGMENT) {
 247                 esph->seq_no = htonl(xo->seq.low);
 248         } else {
 249                 int len;
 250
 251                 len = skb->len - sizeof(struct ipv6hdr);
 252                 if (len > IPV6_MAXPLEN)
 253                         len = 0;
 254
 255                 ipv6_hdr(skb)->payload_len = htons(len);
 256         }
 257
 258         if (hw_offload)
 259                 return 0;
 260
 261         esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
 262
 263         err = esp6_output_tail(x, skb, &esp);
 264         if (err < 0)
 265                 return err;
 266
 267         secpath_reset(skb);
 268
 269         return 0;
 270 }
 271
 272 static const struct net_offload esp6_offload = {
 273         .callbacks = {
 274                 .gro_receive = esp6_gro_receive,
 275                 .gso_segment = esp6_gso_segment,
 276         },
 277 };
 278
 279 static const struct xfrm_type_offload esp6_type_offload = {
 280         .description    = "ESP6 OFFLOAD",
 281         .owner          = THIS_MODULE,
 282         .proto          = IPPROTO_ESP,
 283         .input_tail     = esp6_input_tail,
 284         .xmit           = esp6_xmit,
 285         .encap          = esp6_gso_encap,
 286 };
 287
 288 static int __init esp6_offload_init(void)
 289 {
 290         if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
 291                 pr_info("%s: can't add xfrm type offload\n", __func__);
 292                 return -EAGAIN;
 293         }
 294
 295         return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
 296 }
 297
 298 static void __exit esp6_offload_exit(void)
 299 {
 300         if (xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6) < 0)
 301                 pr_info("%s: can't remove xfrm type offload\n", __func__);
 302
 303         inet6_del_offload(&esp6_offload, IPPROTO_ESP);
 304 }
 305
 306 module_init(esp6_offload_init);
 307 module_exit(esp6_offload_exit);
 308 MODULE_LICENSE("GPL");
 309 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");