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 __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen) 34 { 35 int off = sizeof(struct ipv6hdr); 36 struct ipv6_opt_hdr *exthdr; 37 38 if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP)) 39 return offsetof(struct ipv6hdr, nexthdr); 40 41 while (off < nhlen) { 42 exthdr = (void *)ipv6_hdr + off; 43 if (exthdr->nexthdr == NEXTHDR_ESP) 44 return off; 45 46 off += ipv6_optlen(exthdr); 47 } 48 49 return 0; 50 } 51 52 static struct sk_buff **esp6_gro_receive(struct sk_buff **head, 53 struct sk_buff *skb) 54 { 55 int offset = skb_gro_offset(skb); 56 struct xfrm_offload *xo; 57 struct xfrm_state *x; 58 __be32 seq; 59 __be32 spi; 60 int nhoff; 61 int err; 62 63 if (!pskb_pull(skb, offset)) 64 return NULL; 65 66 if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0) 67 goto out; 68 69 xo = xfrm_offload(skb); 70 if (!xo || !(xo->flags & CRYPTO_DONE)) { 71 err = secpath_set(skb); 72 if (err) 73 goto out; 74 75 if (skb->sp->len == XFRM_MAX_DEPTH) 76 goto out; 77 78 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark, 79 (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 80 spi, IPPROTO_ESP, AF_INET6); 81 if (!x) 82 goto out; 83 84 skb->sp->xvec[skb->sp->len++] = x; 85 skb->sp->olen++; 86 87 xo = xfrm_offload(skb); 88 if (!xo) { 89 xfrm_state_put(x); 90 goto out; 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: 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 *esp6_gso_segment(struct sk_buff *skb, 137 netdev_features_t features) 138 { 139 struct xfrm_state *x; 140 struct ip_esp_hdr *esph; 141 struct crypto_aead *aead; 142 netdev_features_t esp_features = features; 143 struct xfrm_offload *xo = xfrm_offload(skb); 144 145 if (!xo) 146 return ERR_PTR(-EINVAL); 147 148 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP)) 149 return ERR_PTR(-EINVAL); 150 151 x = skb->sp->xvec[skb->sp->len - 1]; 152 aead = x->data; 153 esph = ip_esp_hdr(skb); 154 155 if (esph->spi != x->id.spi) 156 return ERR_PTR(-EINVAL); 157 158 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) 159 return ERR_PTR(-EINVAL); 160 161 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)); 162 163 skb->encap_hdr_csum = 1; 164 165 if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle || 166 (x->xso.dev != skb->dev)) 167 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK); 168 else if (!(features & NETIF_F_HW_ESP_TX_CSUM)) 169 esp_features = features & ~NETIF_F_CSUM_MASK; 170 171 xo->flags |= XFRM_GSO_SEGMENT; 172 173 return x->outer_mode->gso_segment(x, skb, esp_features); 174 } 175 176 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb) 177 { 178 struct crypto_aead *aead = x->data; 179 struct xfrm_offload *xo = xfrm_offload(skb); 180 181 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead))) 182 return -EINVAL; 183 184 if (!(xo->flags & CRYPTO_DONE)) 185 skb->ip_summed = CHECKSUM_NONE; 186 187 return esp6_input_done2(skb, 0); 188 } 189 190 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features) 191 { 192 int len; 193 int err; 194 int alen; 195 int blksize; 196 struct xfrm_offload *xo; 197 struct ip_esp_hdr *esph; 198 struct crypto_aead *aead; 199 struct esp_info esp; 200 bool hw_offload = true; 201 __u32 seq; 202 203 esp.inplace = true; 204 205 xo = xfrm_offload(skb); 206 207 if (!xo) 208 return -EINVAL; 209 210 if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle || 211 (x->xso.dev != skb->dev)) { 212 xo->flags |= CRYPTO_FALLBACK; 213 hw_offload = false; 214 } 215 216 esp.proto = xo->proto; 217 218 /* skb is pure payload to encrypt */ 219 220 aead = x->data; 221 alen = crypto_aead_authsize(aead); 222 223 esp.tfclen = 0; 224 /* XXX: Add support for tfc padding here. */ 225 226 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 227 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 228 esp.plen = esp.clen - skb->len - esp.tfclen; 229 esp.tailen = esp.tfclen + esp.plen + alen; 230 231 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) { 232 esp.nfrags = esp6_output_head(x, skb, &esp); 233 if (esp.nfrags < 0) 234 return esp.nfrags; 235 } 236 237 seq = xo->seq.low; 238 239 esph = ip_esp_hdr(skb); 240 esph->spi = x->id.spi; 241 242 skb_push(skb, -skb_network_offset(skb)); 243 244 if (xo->flags & XFRM_GSO_SEGMENT) { 245 esph->seq_no = htonl(seq); 246 247 if (!skb_is_gso(skb)) 248 xo->seq.low++; 249 else 250 xo->seq.low += skb_shinfo(skb)->gso_segs; 251 } 252 253 esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32)); 254 255 len = skb->len - sizeof(struct ipv6hdr); 256 if (len > IPV6_MAXPLEN) 257 len = 0; 258 259 ipv6_hdr(skb)->payload_len = htons(len); 260 261 if (hw_offload) 262 return 0; 263 264 err = esp6_output_tail(x, skb, &esp); 265 if (err) 266 return err; 267 268 secpath_reset(skb); 269 270 return 0; 271 } 272 273 static const struct net_offload esp6_offload = { 274 .callbacks = { 275 .gro_receive = esp6_gro_receive, 276 .gso_segment = esp6_gso_segment, 277 }, 278 }; 279 280 static const struct xfrm_type_offload esp6_type_offload = { 281 .description = "ESP6 OFFLOAD", 282 .owner = THIS_MODULE, 283 .proto = IPPROTO_ESP, 284 .input_tail = esp6_input_tail, 285 .xmit = esp6_xmit, 286 .encap = esp6_gso_encap, 287 }; 288 289 static int __init esp6_offload_init(void) 290 { 291 if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) { 292 pr_info("%s: can't add xfrm type offload\n", __func__); 293 return -EAGAIN; 294 } 295 296 return inet6_add_offload(&esp6_offload, IPPROTO_ESP); 297 } 298 299 static void __exit esp6_offload_exit(void) 300 { 301 if (xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6) < 0) 302 pr_info("%s: can't remove xfrm type offload\n", __func__); 303 304 inet6_del_offload(&esp6_offload, IPPROTO_ESP); 305 } 306 307 module_init(esp6_offload_init); 308 module_exit(esp6_offload_exit); 309 MODULE_LICENSE("GPL"); 310 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); 311 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP); 312