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 skb_pull(skb, offset); 42 43 if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0) 44 goto out; 45 46 xo = xfrm_offload(skb); 47 if (!xo || !(xo->flags & CRYPTO_DONE)) { 48 err = secpath_set(skb); 49 if (err) 50 goto out; 51 52 if (skb->sp->len == XFRM_MAX_DEPTH) 53 goto out; 54 55 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark, 56 (xfrm_address_t *)&ip_hdr(skb)->daddr, 57 spi, IPPROTO_ESP, AF_INET); 58 if (!x) 59 goto out; 60 61 skb->sp->xvec[skb->sp->len++] = x; 62 skb->sp->olen++; 63 64 xo = xfrm_offload(skb); 65 if (!xo) { 66 xfrm_state_put(x); 67 goto out; 68 } 69 } 70 71 xo->flags |= XFRM_GRO; 72 73 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL; 74 XFRM_SPI_SKB_CB(skb)->family = AF_INET; 75 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr); 76 XFRM_SPI_SKB_CB(skb)->seq = seq; 77 78 /* We don't need to handle errors from xfrm_input, it does all 79 * the error handling and frees the resources on error. */ 80 xfrm_input(skb, IPPROTO_ESP, spi, -2); 81 82 return ERR_PTR(-EINPROGRESS); 83 out: 84 skb_push(skb, offset); 85 NAPI_GRO_CB(skb)->same_flow = 0; 86 NAPI_GRO_CB(skb)->flush = 1; 87 88 return NULL; 89 } 90 91 static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb) 92 { 93 struct ip_esp_hdr *esph; 94 struct iphdr *iph = ip_hdr(skb); 95 struct xfrm_offload *xo = xfrm_offload(skb); 96 int proto = iph->protocol; 97 98 skb_push(skb, -skb_network_offset(skb)); 99 esph = ip_esp_hdr(skb); 100 *skb_mac_header(skb) = IPPROTO_ESP; 101 102 esph->spi = x->id.spi; 103 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 104 105 xo->proto = proto; 106 } 107 108 static struct sk_buff *esp4_gso_segment(struct sk_buff *skb, 109 netdev_features_t features) 110 { 111 __u32 seq; 112 int err = 0; 113 struct sk_buff *skb2; 114 struct xfrm_state *x; 115 struct ip_esp_hdr *esph; 116 struct crypto_aead *aead; 117 struct sk_buff *segs = ERR_PTR(-EINVAL); 118 netdev_features_t esp_features = features; 119 struct xfrm_offload *xo = xfrm_offload(skb); 120 121 if (!xo) 122 goto out; 123 124 seq = xo->seq.low; 125 126 x = skb->sp->xvec[skb->sp->len - 1]; 127 aead = x->data; 128 esph = ip_esp_hdr(skb); 129 130 if (esph->spi != x->id.spi) 131 goto out; 132 133 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) 134 goto out; 135 136 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)); 137 138 skb->encap_hdr_csum = 1; 139 140 if (!(features & NETIF_F_HW_ESP)) 141 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK); 142 143 segs = x->outer_mode->gso_segment(x, skb, esp_features); 144 if (IS_ERR_OR_NULL(segs)) 145 goto out; 146 147 __skb_pull(skb, skb->data - skb_mac_header(skb)); 148 149 skb2 = segs; 150 do { 151 struct sk_buff *nskb = skb2->next; 152 153 xo = xfrm_offload(skb2); 154 xo->flags |= XFRM_GSO_SEGMENT; 155 xo->seq.low = seq; 156 xo->seq.hi = xfrm_replay_seqhi(x, seq); 157 158 if(!(features & NETIF_F_HW_ESP)) 159 xo->flags |= CRYPTO_FALLBACK; 160 161 x->outer_mode->xmit(x, skb2); 162 163 err = x->type_offload->xmit(x, skb2, esp_features); 164 if (err) { 165 kfree_skb_list(segs); 166 return ERR_PTR(err); 167 } 168 169 if (!skb_is_gso(skb2)) 170 seq++; 171 else 172 seq += skb_shinfo(skb2)->gso_segs; 173 174 skb_push(skb2, skb2->mac_len); 175 skb2 = nskb; 176 } while (skb2); 177 178 out: 179 return segs; 180 } 181 182 static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb) 183 { 184 struct crypto_aead *aead = x->data; 185 struct xfrm_offload *xo = xfrm_offload(skb); 186 187 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead))) 188 return -EINVAL; 189 190 if (!(xo->flags & CRYPTO_DONE)) 191 skb->ip_summed = CHECKSUM_NONE; 192 193 return esp_input_done2(skb, 0); 194 } 195 196 static int esp_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 esp.esph = ip_esp_hdr(skb); 236 237 238 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) { 239 esp.nfrags = esp_output_head(x, skb, &esp); 240 if (esp.nfrags < 0) 241 return esp.nfrags; 242 } 243 244 esph = esp.esph; 245 esph->spi = x->id.spi; 246 247 skb_push(skb, -skb_network_offset(skb)); 248 249 if (xo->flags & XFRM_GSO_SEGMENT) { 250 esph->seq_no = htonl(xo->seq.low); 251 } else { 252 ip_hdr(skb)->tot_len = htons(skb->len); 253 ip_send_check(ip_hdr(skb)); 254 } 255 256 if (hw_offload) 257 return 0; 258 259 esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32)); 260 261 err = esp_output_tail(x, skb, &esp); 262 if (err) 263 return err; 264 265 secpath_reset(skb); 266 267 return 0; 268 } 269 270 static const struct net_offload esp4_offload = { 271 .callbacks = { 272 .gro_receive = esp4_gro_receive, 273 .gso_segment = esp4_gso_segment, 274 }, 275 }; 276 277 static const struct xfrm_type_offload esp_type_offload = { 278 .description = "ESP4 OFFLOAD", 279 .owner = THIS_MODULE, 280 .proto = IPPROTO_ESP, 281 .input_tail = esp_input_tail, 282 .xmit = esp_xmit, 283 .encap = esp4_gso_encap, 284 }; 285 286 static int __init esp4_offload_init(void) 287 { 288 if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) { 289 pr_info("%s: can't add xfrm type offload\n", __func__); 290 return -EAGAIN; 291 } 292 293 return inet_add_offload(&esp4_offload, IPPROTO_ESP); 294 } 295 296 static void __exit esp4_offload_exit(void) 297 { 298 if (xfrm_unregister_type_offload(&esp_type_offload, AF_INET) < 0) 299 pr_info("%s: can't remove xfrm type offload\n", __func__); 300 301 inet_del_offload(&esp4_offload, IPPROTO_ESP); 302 } 303 304 module_init(esp4_offload_init); 305 module_exit(esp4_offload_exit); 306 MODULE_LICENSE("GPL"); 307 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); 308 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP); 309