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 struct xfrm_state *x; 113 struct ip_esp_hdr *esph; 114 struct crypto_aead *aead; 115 netdev_features_t esp_features = features; 116 struct xfrm_offload *xo = xfrm_offload(skb); 117 118 if (!xo) 119 return ERR_PTR(-EINVAL); 120 121 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP)) 122 return ERR_PTR(-EINVAL); 123 124 x = skb->sp->xvec[skb->sp->len - 1]; 125 aead = x->data; 126 esph = ip_esp_hdr(skb); 127 128 if (esph->spi != x->id.spi) 129 return ERR_PTR(-EINVAL); 130 131 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) 132 return ERR_PTR(-EINVAL); 133 134 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)); 135 136 skb->encap_hdr_csum = 1; 137 138 if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle || 139 (x->xso.dev != skb->dev)) 140 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK); 141 else if (!(features & NETIF_F_HW_ESP_TX_CSUM)) 142 esp_features = features & ~NETIF_F_CSUM_MASK; 143 144 xo->flags |= XFRM_GSO_SEGMENT; 145 146 return x->outer_mode->gso_segment(x, skb, esp_features); 147 } 148 149 static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb) 150 { 151 struct crypto_aead *aead = x->data; 152 struct xfrm_offload *xo = xfrm_offload(skb); 153 154 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead))) 155 return -EINVAL; 156 157 if (!(xo->flags & CRYPTO_DONE)) 158 skb->ip_summed = CHECKSUM_NONE; 159 160 return esp_input_done2(skb, 0); 161 } 162 163 static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features) 164 { 165 int err; 166 int alen; 167 int blksize; 168 struct xfrm_offload *xo; 169 struct ip_esp_hdr *esph; 170 struct crypto_aead *aead; 171 struct esp_info esp; 172 bool hw_offload = true; 173 __u32 seq; 174 175 esp.inplace = true; 176 177 xo = xfrm_offload(skb); 178 179 if (!xo) 180 return -EINVAL; 181 182 if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle || 183 (x->xso.dev != skb->dev)) { 184 xo->flags |= CRYPTO_FALLBACK; 185 hw_offload = false; 186 } 187 188 esp.proto = xo->proto; 189 190 /* skb is pure payload to encrypt */ 191 192 aead = x->data; 193 alen = crypto_aead_authsize(aead); 194 195 esp.tfclen = 0; 196 /* XXX: Add support for tfc padding here. */ 197 198 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 199 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 200 esp.plen = esp.clen - skb->len - esp.tfclen; 201 esp.tailen = esp.tfclen + esp.plen + alen; 202 203 esp.esph = ip_esp_hdr(skb); 204 205 206 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) { 207 esp.nfrags = esp_output_head(x, skb, &esp); 208 if (esp.nfrags < 0) 209 return esp.nfrags; 210 } 211 212 seq = xo->seq.low; 213 214 esph = esp.esph; 215 esph->spi = x->id.spi; 216 217 skb_push(skb, -skb_network_offset(skb)); 218 219 if (xo->flags & XFRM_GSO_SEGMENT) { 220 esph->seq_no = htonl(seq); 221 222 if (!skb_is_gso(skb)) 223 xo->seq.low++; 224 else 225 xo->seq.low += skb_shinfo(skb)->gso_segs; 226 } 227 228 esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32)); 229 230 ip_hdr(skb)->tot_len = htons(skb->len); 231 ip_send_check(ip_hdr(skb)); 232 233 if (hw_offload) 234 return 0; 235 236 err = esp_output_tail(x, skb, &esp); 237 if (err) 238 return err; 239 240 secpath_reset(skb); 241 242 return 0; 243 } 244 245 static const struct net_offload esp4_offload = { 246 .callbacks = { 247 .gro_receive = esp4_gro_receive, 248 .gso_segment = esp4_gso_segment, 249 }, 250 }; 251 252 static const struct xfrm_type_offload esp_type_offload = { 253 .description = "ESP4 OFFLOAD", 254 .owner = THIS_MODULE, 255 .proto = IPPROTO_ESP, 256 .input_tail = esp_input_tail, 257 .xmit = esp_xmit, 258 .encap = esp4_gso_encap, 259 }; 260 261 static int __init esp4_offload_init(void) 262 { 263 if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) { 264 pr_info("%s: can't add xfrm type offload\n", __func__); 265 return -EAGAIN; 266 } 267 268 return inet_add_offload(&esp4_offload, IPPROTO_ESP); 269 } 270 271 static void __exit esp4_offload_exit(void) 272 { 273 if (xfrm_unregister_type_offload(&esp_type_offload, AF_INET) < 0) 274 pr_info("%s: can't remove xfrm type offload\n", __func__); 275 276 inet_del_offload(&esp4_offload, IPPROTO_ESP); 277 } 278 279 module_init(esp4_offload_init); 280 module_exit(esp4_offload_exit); 281 MODULE_LICENSE("GPL"); 282 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); 283 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP); 284