1 /* 2 * IPV4 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/udp.h> 30 31 static struct sk_buff **esp4_gro_receive(struct sk_buff **head, 32 struct sk_buff *skb) 33 { 34 int offset = skb_gro_offset(skb); 35 struct xfrm_offload *xo; 36 struct xfrm_state *x; 37 __be32 seq; 38 __be32 spi; 39 int err; 40 41 if (!pskb_pull(skb, offset)) 42 return NULL; 43 44 if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0) 45 goto out; 46 47 xo = xfrm_offload(skb); 48 if (!xo || !(xo->flags & CRYPTO_DONE)) { 49 err = secpath_set(skb); 50 if (err) 51 goto out; 52 53 if (skb->sp->len == XFRM_MAX_DEPTH) 54 goto out; 55 56 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark, 57 (xfrm_address_t *)&ip_hdr(skb)->daddr, 58 spi, IPPROTO_ESP, AF_INET); 59 if (!x) 60 goto out; 61 62 skb->sp->xvec[skb->sp->len++] = x; 63 skb->sp->olen++; 64 65 xo = xfrm_offload(skb); 66 if (!xo) { 67 xfrm_state_put(x); 68 goto out; 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: 85 skb_push(skb, offset); 86 NAPI_GRO_CB(skb)->same_flow = 0; 87 NAPI_GRO_CB(skb)->flush = 1; 88 89 return NULL; 90 } 91 92 static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb) 93 { 94 struct ip_esp_hdr *esph; 95 struct iphdr *iph = ip_hdr(skb); 96 struct xfrm_offload *xo = xfrm_offload(skb); 97 int proto = iph->protocol; 98 99 skb_push(skb, -skb_network_offset(skb)); 100 esph = ip_esp_hdr(skb); 101 *skb_mac_header(skb) = IPPROTO_ESP; 102 103 esph->spi = x->id.spi; 104 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 105 106 xo->proto = proto; 107 } 108 109 static struct sk_buff *esp4_gso_segment(struct sk_buff *skb, 110 netdev_features_t features) 111 { 112 __u32 seq; 113 int err = 0; 114 struct sk_buff *skb2; 115 struct xfrm_state *x; 116 struct ip_esp_hdr *esph; 117 struct crypto_aead *aead; 118 struct sk_buff *segs = ERR_PTR(-EINVAL); 119 netdev_features_t esp_features = features; 120 struct xfrm_offload *xo = xfrm_offload(skb); 121 122 if (!xo) 123 goto out; 124 125 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP)) 126 goto out; 127 128 seq = xo->seq.low; 129 130 x = skb->sp->xvec[skb->sp->len - 1]; 131 aead = x->data; 132 esph = ip_esp_hdr(skb); 133 134 if (esph->spi != x->id.spi) 135 goto out; 136 137 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) 138 goto out; 139 140 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)); 141 142 skb->encap_hdr_csum = 1; 143 144 if (!(features & NETIF_F_HW_ESP)) 145 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK); 146 147 segs = x->outer_mode->gso_segment(x, skb, esp_features); 148 if (IS_ERR_OR_NULL(segs)) 149 goto out; 150 151 __skb_pull(skb, skb->data - skb_mac_header(skb)); 152 153 skb2 = segs; 154 do { 155 struct sk_buff *nskb = skb2->next; 156 157 xo = xfrm_offload(skb2); 158 xo->flags |= XFRM_GSO_SEGMENT; 159 xo->seq.low = seq; 160 xo->seq.hi = xfrm_replay_seqhi(x, seq); 161 162 if(!(features & NETIF_F_HW_ESP)) 163 xo->flags |= CRYPTO_FALLBACK; 164 165 x->outer_mode->xmit(x, skb2); 166 167 err = x->type_offload->xmit(x, skb2, esp_features); 168 if (err) { 169 kfree_skb_list(segs); 170 return ERR_PTR(err); 171 } 172 173 if (!skb_is_gso(skb2)) 174 seq++; 175 else 176 seq += skb_shinfo(skb2)->gso_segs; 177 178 skb_push(skb2, skb2->mac_len); 179 skb2 = nskb; 180 } while (skb2); 181 182 out: 183 return segs; 184 } 185 186 static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb) 187 { 188 struct crypto_aead *aead = x->data; 189 struct xfrm_offload *xo = xfrm_offload(skb); 190 191 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead))) 192 return -EINVAL; 193 194 if (!(xo->flags & CRYPTO_DONE)) 195 skb->ip_summed = CHECKSUM_NONE; 196 197 return esp_input_done2(skb, 0); 198 } 199 200 static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features) 201 { 202 int err; 203 int alen; 204 int blksize; 205 struct xfrm_offload *xo; 206 struct ip_esp_hdr *esph; 207 struct crypto_aead *aead; 208 struct esp_info esp; 209 bool hw_offload = true; 210 211 esp.inplace = true; 212 213 xo = xfrm_offload(skb); 214 215 if (!xo) 216 return -EINVAL; 217 218 if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle || 219 (x->xso.dev != skb->dev)) { 220 xo->flags |= CRYPTO_FALLBACK; 221 hw_offload = false; 222 } 223 224 esp.proto = xo->proto; 225 226 /* skb is pure payload to encrypt */ 227 228 aead = x->data; 229 alen = crypto_aead_authsize(aead); 230 231 esp.tfclen = 0; 232 /* XXX: Add support for tfc padding here. */ 233 234 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 235 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 236 esp.plen = esp.clen - skb->len - esp.tfclen; 237 esp.tailen = esp.tfclen + esp.plen + alen; 238 239 esp.esph = ip_esp_hdr(skb); 240 241 242 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) { 243 esp.nfrags = esp_output_head(x, skb, &esp); 244 if (esp.nfrags < 0) 245 return esp.nfrags; 246 } 247 248 esph = esp.esph; 249 esph->spi = x->id.spi; 250 251 skb_push(skb, -skb_network_offset(skb)); 252 253 if (xo->flags & XFRM_GSO_SEGMENT) { 254 esph->seq_no = htonl(xo->seq.low); 255 } else { 256 ip_hdr(skb)->tot_len = htons(skb->len); 257 ip_send_check(ip_hdr(skb)); 258 } 259 260 if (hw_offload) 261 return 0; 262 263 esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32)); 264 265 err = esp_output_tail(x, skb, &esp); 266 if (err) 267 return err; 268 269 secpath_reset(skb); 270 271 return 0; 272 } 273 274 static const struct net_offload esp4_offload = { 275 .callbacks = { 276 .gro_receive = esp4_gro_receive, 277 .gso_segment = esp4_gso_segment, 278 }, 279 }; 280 281 static const struct xfrm_type_offload esp_type_offload = { 282 .description = "ESP4 OFFLOAD", 283 .owner = THIS_MODULE, 284 .proto = IPPROTO_ESP, 285 .input_tail = esp_input_tail, 286 .xmit = esp_xmit, 287 .encap = esp4_gso_encap, 288 }; 289 290 static int __init esp4_offload_init(void) 291 { 292 if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) { 293 pr_info("%s: can't add xfrm type offload\n", __func__); 294 return -EAGAIN; 295 } 296 297 return inet_add_offload(&esp4_offload, IPPROTO_ESP); 298 } 299 300 static void __exit esp4_offload_exit(void) 301 { 302 if (xfrm_unregister_type_offload(&esp_type_offload, AF_INET) < 0) 303 pr_info("%s: can't remove xfrm type offload\n", __func__); 304 305 inet_del_offload(&esp4_offload, IPPROTO_ESP); 306 } 307 308 module_init(esp4_offload_init); 309 module_exit(esp4_offload_exit); 310 MODULE_LICENSE("GPL"); 311 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); 312 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP); 313