1 /* 2 * IPV6 GSO/GRO offload support 3 * Linux INET6 implementation 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License 7 * as published by the Free Software Foundation; either version 8 * 2 of the License, or (at your option) any later version. 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/socket.h> 13 #include <linux/netdevice.h> 14 #include <linux/skbuff.h> 15 #include <linux/printk.h> 16 17 #include <net/protocol.h> 18 #include <net/ipv6.h> 19 #include <net/inet_common.h> 20 21 #include "ip6_offload.h" 22 23 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 24 { 25 const struct net_offload *ops = NULL; 26 27 for (;;) { 28 struct ipv6_opt_hdr *opth; 29 int len; 30 31 if (proto != NEXTHDR_HOP) { 32 ops = rcu_dereference(inet6_offloads[proto]); 33 34 if (unlikely(!ops)) 35 break; 36 37 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 38 break; 39 } 40 41 if (unlikely(!pskb_may_pull(skb, 8))) 42 break; 43 44 opth = (void *)skb->data; 45 len = ipv6_optlen(opth); 46 47 if (unlikely(!pskb_may_pull(skb, len))) 48 break; 49 50 opth = (void *)skb->data; 51 proto = opth->nexthdr; 52 __skb_pull(skb, len); 53 } 54 55 return proto; 56 } 57 58 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 59 netdev_features_t features) 60 { 61 struct sk_buff *segs = ERR_PTR(-EINVAL); 62 struct ipv6hdr *ipv6h; 63 const struct net_offload *ops; 64 int proto; 65 struct frag_hdr *fptr; 66 unsigned int unfrag_ip6hlen; 67 unsigned int payload_len; 68 u8 *prevhdr; 69 int offset = 0; 70 bool encap, udpfrag; 71 int nhoff; 72 73 skb_reset_network_header(skb); 74 nhoff = skb_network_header(skb) - skb_mac_header(skb); 75 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 76 goto out; 77 78 encap = SKB_GSO_CB(skb)->encap_level > 0; 79 if (encap) 80 features &= skb->dev->hw_enc_features; 81 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 82 83 ipv6h = ipv6_hdr(skb); 84 __skb_pull(skb, sizeof(*ipv6h)); 85 segs = ERR_PTR(-EPROTONOSUPPORT); 86 87 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 88 89 if (skb->encapsulation && 90 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6)) 91 udpfrag = proto == IPPROTO_UDP && encap; 92 else 93 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation; 94 95 ops = rcu_dereference(inet6_offloads[proto]); 96 if (likely(ops && ops->callbacks.gso_segment)) { 97 skb_reset_transport_header(skb); 98 segs = ops->callbacks.gso_segment(skb, features); 99 } 100 101 if (IS_ERR(segs)) 102 goto out; 103 104 for (skb = segs; skb; skb = skb->next) { 105 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 106 if (skb_is_gso(skb)) 107 payload_len = skb_shinfo(skb)->gso_size + 108 SKB_GSO_CB(skb)->data_offset + 109 skb->head - (unsigned char *)(ipv6h + 1); 110 else 111 payload_len = skb->len - nhoff - sizeof(*ipv6h); 112 ipv6h->payload_len = htons(payload_len); 113 skb->network_header = (u8 *)ipv6h - skb->head; 114 115 if (udpfrag) { 116 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 117 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen); 118 fptr->frag_off = htons(offset); 119 if (skb->next) 120 fptr->frag_off |= htons(IP6_MF); 121 offset += (ntohs(ipv6h->payload_len) - 122 sizeof(struct frag_hdr)); 123 } 124 if (encap) 125 skb_reset_inner_headers(skb); 126 } 127 128 out: 129 return segs; 130 } 131 132 /* Return the total length of all the extension hdrs, following the same 133 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 134 */ 135 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 136 const struct net_offload **opps) 137 { 138 struct ipv6_opt_hdr *opth = (void *)iph; 139 int len = 0, proto, optlen = sizeof(*iph); 140 141 proto = iph->nexthdr; 142 for (;;) { 143 if (proto != NEXTHDR_HOP) { 144 *opps = rcu_dereference(inet6_offloads[proto]); 145 if (unlikely(!(*opps))) 146 break; 147 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 148 break; 149 } 150 opth = (void *)opth + optlen; 151 optlen = ipv6_optlen(opth); 152 len += optlen; 153 proto = opth->nexthdr; 154 } 155 return len; 156 } 157 158 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 159 struct sk_buff *skb) 160 { 161 const struct net_offload *ops; 162 struct sk_buff **pp = NULL; 163 struct sk_buff *p; 164 struct ipv6hdr *iph; 165 unsigned int nlen; 166 unsigned int hlen; 167 unsigned int off; 168 u16 flush = 1; 169 int proto; 170 171 off = skb_gro_offset(skb); 172 hlen = off + sizeof(*iph); 173 iph = skb_gro_header_fast(skb, off); 174 if (skb_gro_header_hard(skb, hlen)) { 175 iph = skb_gro_header_slow(skb, hlen, off); 176 if (unlikely(!iph)) 177 goto out; 178 } 179 180 skb_set_network_header(skb, off); 181 skb_gro_pull(skb, sizeof(*iph)); 182 skb_set_transport_header(skb, skb_gro_offset(skb)); 183 184 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 185 186 rcu_read_lock(); 187 proto = iph->nexthdr; 188 ops = rcu_dereference(inet6_offloads[proto]); 189 if (!ops || !ops->callbacks.gro_receive) { 190 __pskb_pull(skb, skb_gro_offset(skb)); 191 proto = ipv6_gso_pull_exthdrs(skb, proto); 192 skb_gro_pull(skb, -skb_transport_offset(skb)); 193 skb_reset_transport_header(skb); 194 __skb_push(skb, skb_gro_offset(skb)); 195 196 ops = rcu_dereference(inet6_offloads[proto]); 197 if (!ops || !ops->callbacks.gro_receive) 198 goto out_unlock; 199 200 iph = ipv6_hdr(skb); 201 } 202 203 NAPI_GRO_CB(skb)->proto = proto; 204 205 flush--; 206 nlen = skb_network_header_len(skb); 207 208 for (p = *head; p; p = p->next) { 209 const struct ipv6hdr *iph2; 210 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 211 212 if (!NAPI_GRO_CB(p)->same_flow) 213 continue; 214 215 iph2 = (struct ipv6hdr *)(p->data + off); 216 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 217 218 /* All fields must match except length and Traffic Class. 219 * XXX skbs on the gro_list have all been parsed and pulled 220 * already so we don't need to compare nlen 221 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 222 * memcmp() alone below is suffcient, right? 223 */ 224 if ((first_word & htonl(0xF00FFFFF)) || 225 memcmp(&iph->nexthdr, &iph2->nexthdr, 226 nlen - offsetof(struct ipv6hdr, nexthdr))) { 227 NAPI_GRO_CB(p)->same_flow = 0; 228 continue; 229 } 230 /* flush if Traffic Class fields are different */ 231 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 232 NAPI_GRO_CB(p)->flush |= flush; 233 234 /* If the previous IP ID value was based on an atomic 235 * datagram we can overwrite the value and ignore it. 236 */ 237 if (NAPI_GRO_CB(skb)->is_atomic) 238 NAPI_GRO_CB(p)->flush_id = 0; 239 } 240 241 NAPI_GRO_CB(skb)->is_atomic = true; 242 NAPI_GRO_CB(skb)->flush |= flush; 243 244 skb_gro_postpull_rcsum(skb, iph, nlen); 245 246 pp = ops->callbacks.gro_receive(head, skb); 247 248 out_unlock: 249 rcu_read_unlock(); 250 251 out: 252 NAPI_GRO_CB(skb)->flush |= flush; 253 254 return pp; 255 } 256 257 static struct sk_buff **sit_ip6ip6_gro_receive(struct sk_buff **head, 258 struct sk_buff *skb) 259 { 260 /* Common GRO receive for SIT and IP6IP6 */ 261 262 if (NAPI_GRO_CB(skb)->encap_mark) { 263 NAPI_GRO_CB(skb)->flush = 1; 264 return NULL; 265 } 266 267 NAPI_GRO_CB(skb)->encap_mark = 1; 268 269 return ipv6_gro_receive(head, skb); 270 } 271 272 static struct sk_buff **ip4ip6_gro_receive(struct sk_buff **head, 273 struct sk_buff *skb) 274 { 275 /* Common GRO receive for SIT and IP6IP6 */ 276 277 if (NAPI_GRO_CB(skb)->encap_mark) { 278 NAPI_GRO_CB(skb)->flush = 1; 279 return NULL; 280 } 281 282 NAPI_GRO_CB(skb)->encap_mark = 1; 283 284 return inet_gro_receive(head, skb); 285 } 286 287 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 288 { 289 const struct net_offload *ops; 290 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 291 int err = -ENOSYS; 292 293 if (skb->encapsulation) 294 skb_set_inner_network_header(skb, nhoff); 295 296 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 297 298 rcu_read_lock(); 299 300 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 301 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 302 goto out_unlock; 303 304 err = ops->callbacks.gro_complete(skb, nhoff); 305 306 out_unlock: 307 rcu_read_unlock(); 308 309 return err; 310 } 311 312 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 313 { 314 skb->encapsulation = 1; 315 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4; 316 return ipv6_gro_complete(skb, nhoff); 317 } 318 319 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff) 320 { 321 skb->encapsulation = 1; 322 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 323 return ipv6_gro_complete(skb, nhoff); 324 } 325 326 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff) 327 { 328 skb->encapsulation = 1; 329 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 330 return inet_gro_complete(skb, nhoff); 331 } 332 333 static struct packet_offload ipv6_packet_offload __read_mostly = { 334 .type = cpu_to_be16(ETH_P_IPV6), 335 .callbacks = { 336 .gso_segment = ipv6_gso_segment, 337 .gro_receive = ipv6_gro_receive, 338 .gro_complete = ipv6_gro_complete, 339 }, 340 }; 341 342 static const struct net_offload sit_offload = { 343 .callbacks = { 344 .gso_segment = ipv6_gso_segment, 345 .gro_receive = sit_ip6ip6_gro_receive, 346 .gro_complete = sit_gro_complete, 347 }, 348 }; 349 350 static const struct net_offload ip4ip6_offload = { 351 .callbacks = { 352 .gso_segment = inet_gso_segment, 353 .gro_receive = ip4ip6_gro_receive, 354 .gro_complete = ip4ip6_gro_complete, 355 }, 356 }; 357 358 static const struct net_offload ip6ip6_offload = { 359 .callbacks = { 360 .gso_segment = ipv6_gso_segment, 361 .gro_receive = sit_ip6ip6_gro_receive, 362 .gro_complete = ip6ip6_gro_complete, 363 }, 364 }; 365 static int __init ipv6_offload_init(void) 366 { 367 368 if (tcpv6_offload_init() < 0) 369 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 370 if (ipv6_exthdrs_offload_init() < 0) 371 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 372 373 dev_add_offload(&ipv6_packet_offload); 374 375 inet_add_offload(&sit_offload, IPPROTO_IPV6); 376 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6); 377 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP); 378 379 return 0; 380 } 381 382 fs_initcall(ipv6_offload_init); 383