net/ipv4/esp4_offload.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * IPV4 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/udp.h>
  27
  28 static struct sk_buff *esp4_gro_receive(struct list_head *head,
  29                                         struct sk_buff *skb)
  30 {
  31         int offset = skb_gro_offset(skb);
  32         struct xfrm_offload *xo;
  33         struct xfrm_state *x;
  34         __be32 seq;
  35         __be32 spi;
  36         int err;
  37
  38         if (!pskb_pull(skb, offset))
  39                 return NULL;
  40
  41         if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
  42                 goto out;
  43
  44         xo = xfrm_offload(skb);
  45         if (!xo || !(xo->flags & CRYPTO_DONE)) {
  46                 struct sec_path *sp = secpath_set(skb);
  47
  48                 if (!sp)
  49                         goto out;
  50
  51                 if (sp->len == XFRM_MAX_DEPTH)
  52                         goto out_reset;
  53
  54                 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
  55                                       (xfrm_address_t *)&ip_hdr(skb)->daddr,
  56                                       spi, IPPROTO_ESP, AF_INET);
  57                 if (!x)
  58                         goto out_reset;
  59
  60                 skb->mark = xfrm_smark_get(skb->mark, x);
  61
  62                 sp->xvec[sp->len++] = x;
  63                 sp->olen++;
  64
  65                 xo = xfrm_offload(skb);
  66                 if (!xo) {
  67                         xfrm_state_put(x);
  68                         goto out_reset;
  69                 }
  70         }
  71
  72         xo->flags |= XFRM_GRO;
  73
  74         XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
  75         XFRM_SPI_SKB_CB(skb)->family = AF_INET;
  76         XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
  77         XFRM_SPI_SKB_CB(skb)->seq = seq;
  78
  79         /* We don't need to handle errors from xfrm_input, it does all
  80          * the error handling and frees the resources on error. */
  81         xfrm_input(skb, IPPROTO_ESP, spi, -2);
  82
  83         return ERR_PTR(-EINPROGRESS);
  84 out_reset:
  85         secpath_reset(skb);
  86 out:
  87         skb_push(skb, offset);
  88         NAPI_GRO_CB(skb)->same_flow = 0;
  89         NAPI_GRO_CB(skb)->flush = 1;
  90
  91         return NULL;
  92 }
  93
  94 static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
  95 {
  96         struct ip_esp_hdr *esph;
  97         struct iphdr *iph = ip_hdr(skb);
  98         struct xfrm_offload *xo = xfrm_offload(skb);
  99         int proto = iph->protocol;
 100
 101         skb_push(skb, -skb_network_offset(skb));
 102         esph = ip_esp_hdr(skb);
 103         *skb_mac_header(skb) = IPPROTO_ESP;
 104
 105         esph->spi = x->id.spi;
 106         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 107
 108         xo->proto = proto;
 109 }
 110
 111 static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
 112                                                 struct sk_buff *skb,
 113                                                 netdev_features_t features)
 114 {
 115         __skb_push(skb, skb->mac_len);
 116         return skb_mac_gso_segment(skb, features);
 117 }
 118
 119 static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
 120                                                    struct sk_buff *skb,
 121                                                    netdev_features_t features)
 122 {
 123         const struct net_offload *ops;
 124         struct sk_buff *segs = ERR_PTR(-EINVAL);
 125         struct xfrm_offload *xo = xfrm_offload(skb);
 126
 127         skb->transport_header += x->props.header_len;
 128         ops = rcu_dereference(inet_offloads[xo->proto]);
 129         if (likely(ops && ops->callbacks.gso_segment))
 130                 segs = ops->callbacks.gso_segment(skb, features);
 131
 132         return segs;
 133 }
 134
 135 static struct sk_buff *xfrm4_outer_mode_gso_segment(struct xfrm_state *x,
 136                                                     struct sk_buff *skb,
 137                                                     netdev_features_t features)
 138 {
 139         switch (x->outer_mode.encap) {
 140         case XFRM_MODE_TUNNEL:
 141                 return xfrm4_tunnel_gso_segment(x, skb, features);
 142         case XFRM_MODE_TRANSPORT:
 143                 return xfrm4_transport_gso_segment(x, skb, features);
 144         }
 145
 146         return ERR_PTR(-EOPNOTSUPP);
 147 }
 148
 149 static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
 150                                         netdev_features_t features)
 151 {
 152         struct xfrm_state *x;
 153         struct ip_esp_hdr *esph;
 154         struct crypto_aead *aead;
 155         netdev_features_t esp_features = features;
 156         struct xfrm_offload *xo = xfrm_offload(skb);
 157         struct sec_path *sp;
 158
 159         if (!xo)
 160                 return ERR_PTR(-EINVAL);
 161
 162         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
 163                 return ERR_PTR(-EINVAL);
 164
 165         sp = skb_sec_path(skb);
 166         x = sp->xvec[sp->len - 1];
 167         aead = x->data;
 168         esph = ip_esp_hdr(skb);
 169
 170         if (esph->spi != x->id.spi)
 171                 return ERR_PTR(-EINVAL);
 172
 173         if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 174                 return ERR_PTR(-EINVAL);
 175
 176         __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
 177
 178         skb->encap_hdr_csum = 1;
 179
 180         if ((!(skb->dev->gso_partial_features & NETIF_F_HW_ESP) &&
 181              !(features & NETIF_F_HW_ESP)) || x->xso.dev != skb->dev)
 182                 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
 183         else if (!(features & NETIF_F_HW_ESP_TX_CSUM) &&
 184                  !(skb->dev->gso_partial_features & NETIF_F_HW_ESP_TX_CSUM))
 185                 esp_features = features & ~NETIF_F_CSUM_MASK;
 186
 187         xo->flags |= XFRM_GSO_SEGMENT;
 188
 189         return xfrm4_outer_mode_gso_segment(x, skb, esp_features);
 190 }
 191
 192 static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
 193 {
 194         struct crypto_aead *aead = x->data;
 195         struct xfrm_offload *xo = xfrm_offload(skb);
 196
 197         if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
 198                 return -EINVAL;
 199
 200         if (!(xo->flags & CRYPTO_DONE))
 201                 skb->ip_summed = CHECKSUM_NONE;
 202
 203         return esp_input_done2(skb, 0);
 204 }
 205
 206 static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
 207 {
 208         int err;
 209         int alen;
 210         int blksize;
 211         struct xfrm_offload *xo;
 212         struct ip_esp_hdr *esph;
 213         struct crypto_aead *aead;
 214         struct esp_info esp;
 215         bool hw_offload = true;
 216         __u32 seq;
 217
 218         esp.inplace = true;
 219
 220         xo = xfrm_offload(skb);
 221
 222         if (!xo)
 223                 return -EINVAL;
 224
 225         if ((!(features & NETIF_F_HW_ESP) &&
 226              !(skb->dev->gso_partial_features & NETIF_F_HW_ESP)) ||
 227             x->xso.dev != skb->dev) {
 228                 xo->flags |= CRYPTO_FALLBACK;
 229                 hw_offload = false;
 230         }
 231
 232         esp.proto = xo->proto;
 233
 234         /* skb is pure payload to encrypt */
 235
 236         aead = x->data;
 237         alen = crypto_aead_authsize(aead);
 238
 239         esp.tfclen = 0;
 240         /* XXX: Add support for tfc padding here. */
 241
 242         blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 243         esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
 244         esp.plen = esp.clen - skb->len - esp.tfclen;
 245         esp.tailen = esp.tfclen + esp.plen + alen;
 246
 247         esp.esph = ip_esp_hdr(skb);
 248
 249
 250         if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
 251                 esp.nfrags = esp_output_head(x, skb, &esp);
 252                 if (esp.nfrags < 0)
 253                         return esp.nfrags;
 254         }
 255
 256         seq = xo->seq.low;
 257
 258         esph = esp.esph;
 259         esph->spi = x->id.spi;
 260
 261         skb_push(skb, -skb_network_offset(skb));
 262
 263         if (xo->flags & XFRM_GSO_SEGMENT) {
 264                 esph->seq_no = htonl(seq);
 265
 266                 if (!skb_is_gso(skb))
 267                         xo->seq.low++;
 268                 else
 269                         xo->seq.low += skb_shinfo(skb)->gso_segs;
 270         }
 271
 272         esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
 273
 274         ip_hdr(skb)->tot_len = htons(skb->len);
 275         ip_send_check(ip_hdr(skb));
 276
 277         if (hw_offload)
 278                 return 0;
 279
 280         err = esp_output_tail(x, skb, &esp);
 281         if (err)
 282                 return err;
 283
 284         secpath_reset(skb);
 285
 286         return 0;
 287 }
 288
 289 static const struct net_offload esp4_offload = {
 290         .callbacks = {
 291                 .gro_receive = esp4_gro_receive,
 292                 .gso_segment = esp4_gso_segment,
 293         },
 294 };
 295
 296 static const struct xfrm_type_offload esp_type_offload = {
 297         .description    = "ESP4 OFFLOAD",
 298         .owner          = THIS_MODULE,
 299         .proto          = IPPROTO_ESP,
 300         .input_tail     = esp_input_tail,
 301         .xmit           = esp_xmit,
 302         .encap          = esp4_gso_encap,
 303 };
 304
 305 static int __init esp4_offload_init(void)
 306 {
 307         if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
 308                 pr_info("%s: can't add xfrm type offload\n", __func__);
 309                 return -EAGAIN;
 310         }
 311
 312         return inet_add_offload(&esp4_offload, IPPROTO_ESP);
 313 }
 314
 315 static void __exit esp4_offload_exit(void)
 316 {
 317         xfrm_unregister_type_offload(&esp_type_offload, AF_INET);
 318         inet_del_offload(&esp4_offload, IPPROTO_ESP);
 319 }
 320
 321 module_init(esp4_offload_init);
 322 module_exit(esp4_offload_exit);
 323 MODULE_LICENSE("GPL");
 324 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 325 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);