net/ipv6/ip6_offload.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      IPV6 GSO/GRO offload support
   4  *      Linux INET6 implementation
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/socket.h>
   9 #include <linux/netdevice.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/printk.h>
  12
  13 #include <net/protocol.h>
  14 #include <net/ipv6.h>
  15 #include <net/inet_common.h>
  16 #include <net/tcp.h>
  17 #include <net/udp.h>
  18
  19 #include "ip6_offload.h"
  20
  21 /* All GRO functions are always builtin, except UDP over ipv6, which lays in
  22  * ipv6 module, as it depends on UDPv6 lookup function, so we need special care
  23  * when ipv6 is built as a module
  24  */
  25 #if IS_BUILTIN(CONFIG_IPV6)
  26 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
  27 #else
  28 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
  29 #endif
  30
  31 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb)     \
  32 ({                                                              \
  33         unlikely(gro_recursion_inc_test(skb)) ?                 \
  34                 NAPI_GRO_CB(skb)->flush |= 1, NULL :            \
  35                 INDIRECT_CALL_L4(cb, f2, f1, head, skb);        \
  36 })
  37
  38 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
  39 {
  40         const struct net_offload *ops = NULL;
  41
  42         for (;;) {
  43                 struct ipv6_opt_hdr *opth;
  44                 int len;
  45
  46                 if (proto != NEXTHDR_HOP) {
  47                         ops = rcu_dereference(inet6_offloads[proto]);
  48
  49                         if (unlikely(!ops))
  50                                 break;
  51
  52                         if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
  53                                 break;
  54                 }
  55
  56                 if (unlikely(!pskb_may_pull(skb, 8)))
  57                         break;
  58
  59                 opth = (void *)skb->data;
  60                 len = ipv6_optlen(opth);
  61
  62                 if (unlikely(!pskb_may_pull(skb, len)))
  63                         break;
  64
  65                 opth = (void *)skb->data;
  66                 proto = opth->nexthdr;
  67                 __skb_pull(skb, len);
  68         }
  69
  70         return proto;
  71 }
  72
  73 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
  74         netdev_features_t features)
  75 {
  76         struct sk_buff *segs = ERR_PTR(-EINVAL);
  77         struct ipv6hdr *ipv6h;
  78         const struct net_offload *ops;
  79         int proto;
  80         struct frag_hdr *fptr;
  81         unsigned int payload_len;
  82         u8 *prevhdr;
  83         int offset = 0;
  84         bool encap, udpfrag;
  85         int nhoff;
  86         bool gso_partial;
  87
  88         skb_reset_network_header(skb);
  89         nhoff = skb_network_header(skb) - skb_mac_header(skb);
  90         if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
  91                 goto out;
  92
  93         encap = SKB_GSO_CB(skb)->encap_level > 0;
  94         if (encap)
  95                 features &= skb->dev->hw_enc_features;
  96         SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
  97
  98         ipv6h = ipv6_hdr(skb);
  99         __skb_pull(skb, sizeof(*ipv6h));
 100         segs = ERR_PTR(-EPROTONOSUPPORT);
 101
 102         proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
 103
 104         if (skb->encapsulation &&
 105             skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
 106                 udpfrag = proto == IPPROTO_UDP && encap &&
 107                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 108         else
 109                 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
 110                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 111
 112         ops = rcu_dereference(inet6_offloads[proto]);
 113         if (likely(ops && ops->callbacks.gso_segment)) {
 114                 skb_reset_transport_header(skb);
 115                 segs = ops->callbacks.gso_segment(skb, features);
 116                 if (!segs)
 117                         skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
 118         }
 119
 120         if (IS_ERR_OR_NULL(segs))
 121                 goto out;
 122
 123         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
 124
 125         for (skb = segs; skb; skb = skb->next) {
 126                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
 127                 if (gso_partial && skb_is_gso(skb))
 128                         payload_len = skb_shinfo(skb)->gso_size +
 129                                       SKB_GSO_CB(skb)->data_offset +
 130                                       skb->head - (unsigned char *)(ipv6h + 1);
 131                 else
 132                         payload_len = skb->len - nhoff - sizeof(*ipv6h);
 133                 ipv6h->payload_len = htons(payload_len);
 134                 skb->network_header = (u8 *)ipv6h - skb->head;
 135                 skb_reset_mac_len(skb);
 136
 137                 if (udpfrag) {
 138                         int err = ip6_find_1stfragopt(skb, &prevhdr);
 139                         if (err < 0) {
 140                                 kfree_skb_list(segs);
 141                                 return ERR_PTR(err);
 142                         }
 143                         fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
 144                         fptr->frag_off = htons(offset);
 145                         if (skb->next)
 146                                 fptr->frag_off |= htons(IP6_MF);
 147                         offset += (ntohs(ipv6h->payload_len) -
 148                                    sizeof(struct frag_hdr));
 149                 }
 150                 if (encap)
 151                         skb_reset_inner_headers(skb);
 152         }
 153
 154 out:
 155         return segs;
 156 }
 157
 158 /* Return the total length of all the extension hdrs, following the same
 159  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
 160  */
 161 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
 162                             const struct net_offload **opps)
 163 {
 164         struct ipv6_opt_hdr *opth = (void *)iph;
 165         int len = 0, proto, optlen = sizeof(*iph);
 166
 167         proto = iph->nexthdr;
 168         for (;;) {
 169                 if (proto != NEXTHDR_HOP) {
 170                         *opps = rcu_dereference(inet6_offloads[proto]);
 171                         if (unlikely(!(*opps)))
 172                                 break;
 173                         if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
 174                                 break;
 175                 }
 176                 opth = (void *)opth + optlen;
 177                 optlen = ipv6_optlen(opth);
 178                 len += optlen;
 179                 proto = opth->nexthdr;
 180         }
 181         return len;
 182 }
 183
 184 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
 185                                                          struct sk_buff *skb)
 186 {
 187         const struct net_offload *ops;
 188         struct sk_buff *pp = NULL;
 189         struct sk_buff *p;
 190         struct ipv6hdr *iph;
 191         unsigned int nlen;
 192         unsigned int hlen;
 193         unsigned int off;
 194         u16 flush = 1;
 195         int proto;
 196
 197         off = skb_gro_offset(skb);
 198         hlen = off + sizeof(*iph);
 199         iph = skb_gro_header_fast(skb, off);
 200         if (skb_gro_header_hard(skb, hlen)) {
 201                 iph = skb_gro_header_slow(skb, hlen, off);
 202                 if (unlikely(!iph))
 203                         goto out;
 204         }
 205
 206         skb_set_network_header(skb, off);
 207         skb_gro_pull(skb, sizeof(*iph));
 208         skb_set_transport_header(skb, skb_gro_offset(skb));
 209
 210         flush += ntohs(iph->payload_len) != skb_gro_len(skb);
 211
 212         rcu_read_lock();
 213         proto = iph->nexthdr;
 214         ops = rcu_dereference(inet6_offloads[proto]);
 215         if (!ops || !ops->callbacks.gro_receive) {
 216                 __pskb_pull(skb, skb_gro_offset(skb));
 217                 skb_gro_frag0_invalidate(skb);
 218                 proto = ipv6_gso_pull_exthdrs(skb, proto);
 219                 skb_gro_pull(skb, -skb_transport_offset(skb));
 220                 skb_reset_transport_header(skb);
 221                 __skb_push(skb, skb_gro_offset(skb));
 222
 223                 ops = rcu_dereference(inet6_offloads[proto]);
 224                 if (!ops || !ops->callbacks.gro_receive)
 225                         goto out_unlock;
 226
 227                 iph = ipv6_hdr(skb);
 228         }
 229
 230         NAPI_GRO_CB(skb)->proto = proto;
 231
 232         flush--;
 233         nlen = skb_network_header_len(skb);
 234
 235         list_for_each_entry(p, head, list) {
 236                 const struct ipv6hdr *iph2;
 237                 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
 238
 239                 if (!NAPI_GRO_CB(p)->same_flow)
 240                         continue;
 241
 242                 iph2 = (struct ipv6hdr *)(p->data + off);
 243                 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
 244
 245                 /* All fields must match except length and Traffic Class.
 246                  * XXX skbs on the gro_list have all been parsed and pulled
 247                  * already so we don't need to compare nlen
 248                  * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
 249                  * memcmp() alone below is sufficient, right?
 250                  */
 251                  if ((first_word & htonl(0xF00FFFFF)) ||
 252                     !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
 253                     !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
 254                     *(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) {
 255 not_same_flow:
 256                         NAPI_GRO_CB(p)->same_flow = 0;
 257                         continue;
 258                 }
 259                 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
 260                         if (memcmp(iph + 1, iph2 + 1,
 261                                    nlen - sizeof(struct ipv6hdr)))
 262                                 goto not_same_flow;
 263                 }
 264                 /* flush if Traffic Class fields are different */
 265                 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
 266                 NAPI_GRO_CB(p)->flush |= flush;
 267
 268                 /* If the previous IP ID value was based on an atomic
 269                  * datagram we can overwrite the value and ignore it.
 270                  */
 271                 if (NAPI_GRO_CB(skb)->is_atomic)
 272                         NAPI_GRO_CB(p)->flush_id = 0;
 273         }
 274
 275         NAPI_GRO_CB(skb)->is_atomic = true;
 276         NAPI_GRO_CB(skb)->flush |= flush;
 277
 278         skb_gro_postpull_rcsum(skb, iph, nlen);
 279
 280         pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
 281                                          ops->callbacks.gro_receive, head, skb);
 282
 283 out_unlock:
 284         rcu_read_unlock();
 285
 286 out:
 287         skb_gro_flush_final(skb, pp, flush);
 288
 289         return pp;
 290 }
 291
 292 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
 293                                               struct sk_buff *skb)
 294 {
 295         /* Common GRO receive for SIT and IP6IP6 */
 296
 297         if (NAPI_GRO_CB(skb)->encap_mark) {
 298                 NAPI_GRO_CB(skb)->flush = 1;
 299                 return NULL;
 300         }
 301
 302         NAPI_GRO_CB(skb)->encap_mark = 1;
 303
 304         return ipv6_gro_receive(head, skb);
 305 }
 306
 307 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
 308                                           struct sk_buff *skb)
 309 {
 310         /* Common GRO receive for SIT and IP6IP6 */
 311
 312         if (NAPI_GRO_CB(skb)->encap_mark) {
 313                 NAPI_GRO_CB(skb)->flush = 1;
 314                 return NULL;
 315         }
 316
 317         NAPI_GRO_CB(skb)->encap_mark = 1;
 318
 319         return inet_gro_receive(head, skb);
 320 }
 321
 322 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
 323 {
 324         const struct net_offload *ops;
 325         struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
 326         int err = -ENOSYS;
 327
 328         if (skb->encapsulation) {
 329                 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
 330                 skb_set_inner_network_header(skb, nhoff);
 331         }
 332
 333         iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
 334
 335         rcu_read_lock();
 336
 337         nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
 338         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
 339                 goto out_unlock;
 340
 341         err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
 342                                udp6_gro_complete, skb, nhoff);
 343
 344 out_unlock:
 345         rcu_read_unlock();
 346
 347         return err;
 348 }
 349
 350 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
 351 {
 352         skb->encapsulation = 1;
 353         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
 354         return ipv6_gro_complete(skb, nhoff);
 355 }
 356
 357 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
 358 {
 359         skb->encapsulation = 1;
 360         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 361         return ipv6_gro_complete(skb, nhoff);
 362 }
 363
 364 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
 365 {
 366         skb->encapsulation = 1;
 367         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 368         return inet_gro_complete(skb, nhoff);
 369 }
 370
 371 static struct packet_offload ipv6_packet_offload __read_mostly = {
 372         .type = cpu_to_be16(ETH_P_IPV6),
 373         .callbacks = {
 374                 .gso_segment = ipv6_gso_segment,
 375                 .gro_receive = ipv6_gro_receive,
 376                 .gro_complete = ipv6_gro_complete,
 377         },
 378 };
 379
 380 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
 381                                        netdev_features_t features)
 382 {
 383         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
 384                 return ERR_PTR(-EINVAL);
 385
 386         return ipv6_gso_segment(skb, features);
 387 }
 388
 389 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
 390                                           netdev_features_t features)
 391 {
 392         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 393                 return ERR_PTR(-EINVAL);
 394
 395         return inet_gso_segment(skb, features);
 396 }
 397
 398 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
 399                                           netdev_features_t features)
 400 {
 401         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 402                 return ERR_PTR(-EINVAL);
 403
 404         return ipv6_gso_segment(skb, features);
 405 }
 406
 407 static const struct net_offload sit_offload = {
 408         .callbacks = {
 409                 .gso_segment    = sit_gso_segment,
 410                 .gro_receive    = sit_ip6ip6_gro_receive,
 411                 .gro_complete   = sit_gro_complete,
 412         },
 413 };
 414
 415 static const struct net_offload ip4ip6_offload = {
 416         .callbacks = {
 417                 .gso_segment    = ip4ip6_gso_segment,
 418                 .gro_receive    = ip4ip6_gro_receive,
 419                 .gro_complete   = ip4ip6_gro_complete,
 420         },
 421 };
 422
 423 static const struct net_offload ip6ip6_offload = {
 424         .callbacks = {
 425                 .gso_segment    = ip6ip6_gso_segment,
 426                 .gro_receive    = sit_ip6ip6_gro_receive,
 427                 .gro_complete   = ip6ip6_gro_complete,
 428         },
 429 };
 430 static int __init ipv6_offload_init(void)
 431 {
 432
 433         if (tcpv6_offload_init() < 0)
 434                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
 435         if (ipv6_exthdrs_offload_init() < 0)
 436                 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
 437
 438         dev_add_offload(&ipv6_packet_offload);
 439
 440         inet_add_offload(&sit_offload, IPPROTO_IPV6);
 441         inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
 442         inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
 443
 444         return 0;
 445 }
 446
 447 fs_initcall(ipv6_offload_init);