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
  17 #include "ip6_offload.h"
  18
  19 /* All GRO functions are always builtin, except UDP over ipv6, which lays in
  20  * ipv6 module, as it depends on UDPv6 lookup function, so we need special care
  21  * when ipv6 is built as a module
  22  */
  23 #if IS_BUILTIN(CONFIG_IPV6)
  24 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
  25 #else
  26 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
  27 #endif
  28
  29 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb)     \
  30 ({                                                              \
  31         unlikely(gro_recursion_inc_test(skb)) ?                 \
  32                 NAPI_GRO_CB(skb)->flush |= 1, NULL :            \
  33                 INDIRECT_CALL_L4(cb, f2, f1, head, skb);        \
  34 })
  35
  36 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
  37 {
  38         const struct net_offload *ops = NULL;
  39
  40         for (;;) {
  41                 struct ipv6_opt_hdr *opth;
  42                 int len;
  43
  44                 if (proto != NEXTHDR_HOP) {
  45                         ops = rcu_dereference(inet6_offloads[proto]);
  46
  47                         if (unlikely(!ops))
  48                                 break;
  49
  50                         if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
  51                                 break;
  52                 }
  53
  54                 if (unlikely(!pskb_may_pull(skb, 8)))
  55                         break;
  56
  57                 opth = (void *)skb->data;
  58                 len = ipv6_optlen(opth);
  59
  60                 if (unlikely(!pskb_may_pull(skb, len)))
  61                         break;
  62
  63                 opth = (void *)skb->data;
  64                 proto = opth->nexthdr;
  65                 __skb_pull(skb, len);
  66         }
  67
  68         return proto;
  69 }
  70
  71 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
  72         netdev_features_t features)
  73 {
  74         struct sk_buff *segs = ERR_PTR(-EINVAL);
  75         struct ipv6hdr *ipv6h;
  76         const struct net_offload *ops;
  77         int proto;
  78         struct frag_hdr *fptr;
  79         unsigned int payload_len;
  80         u8 *prevhdr;
  81         int offset = 0;
  82         bool encap, udpfrag;
  83         int nhoff;
  84         bool gso_partial;
  85
  86         skb_reset_network_header(skb);
  87         nhoff = skb_network_header(skb) - skb_mac_header(skb);
  88         if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
  89                 goto out;
  90
  91         encap = SKB_GSO_CB(skb)->encap_level > 0;
  92         if (encap)
  93                 features &= skb->dev->hw_enc_features;
  94         SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
  95
  96         ipv6h = ipv6_hdr(skb);
  97         __skb_pull(skb, sizeof(*ipv6h));
  98         segs = ERR_PTR(-EPROTONOSUPPORT);
  99
 100         proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
 101
 102         if (skb->encapsulation &&
 103             skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
 104                 udpfrag = proto == IPPROTO_UDP && encap &&
 105                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 106         else
 107                 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
 108                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 109
 110         ops = rcu_dereference(inet6_offloads[proto]);
 111         if (likely(ops && ops->callbacks.gso_segment)) {
 112                 skb_reset_transport_header(skb);
 113                 segs = ops->callbacks.gso_segment(skb, features);
 114         }
 115
 116         if (IS_ERR_OR_NULL(segs))
 117                 goto out;
 118
 119         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
 120
 121         for (skb = segs; skb; skb = skb->next) {
 122                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
 123                 if (gso_partial && skb_is_gso(skb))
 124                         payload_len = skb_shinfo(skb)->gso_size +
 125                                       SKB_GSO_CB(skb)->data_offset +
 126                                       skb->head - (unsigned char *)(ipv6h + 1);
 127                 else
 128                         payload_len = skb->len - nhoff - sizeof(*ipv6h);
 129                 ipv6h->payload_len = htons(payload_len);
 130                 skb->network_header = (u8 *)ipv6h - skb->head;
 131                 skb_reset_mac_len(skb);
 132
 133                 if (udpfrag) {
 134                         int err = ip6_find_1stfragopt(skb, &prevhdr);
 135                         if (err < 0) {
 136                                 kfree_skb_list(segs);
 137                                 return ERR_PTR(err);
 138                         }
 139                         fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
 140                         fptr->frag_off = htons(offset);
 141                         if (skb->next)
 142                                 fptr->frag_off |= htons(IP6_MF);
 143                         offset += (ntohs(ipv6h->payload_len) -
 144                                    sizeof(struct frag_hdr));
 145                 }
 146                 if (encap)
 147                         skb_reset_inner_headers(skb);
 148         }
 149
 150 out:
 151         return segs;
 152 }
 153
 154 /* Return the total length of all the extension hdrs, following the same
 155  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
 156  */
 157 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
 158                             const struct net_offload **opps)
 159 {
 160         struct ipv6_opt_hdr *opth = (void *)iph;
 161         int len = 0, proto, optlen = sizeof(*iph);
 162
 163         proto = iph->nexthdr;
 164         for (;;) {
 165                 if (proto != NEXTHDR_HOP) {
 166                         *opps = rcu_dereference(inet6_offloads[proto]);
 167                         if (unlikely(!(*opps)))
 168                                 break;
 169                         if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
 170                                 break;
 171                 }
 172                 opth = (void *)opth + optlen;
 173                 optlen = ipv6_optlen(opth);
 174                 len += optlen;
 175                 proto = opth->nexthdr;
 176         }
 177         return len;
 178 }
 179
 180 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *,
 181                                                            struct sk_buff *));
 182 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *,
 183                                                            struct sk_buff *));
 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_DECLARE(int tcp6_gro_complete(struct sk_buff *, int));
 323 INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int));
 324 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
 325 {
 326         const struct net_offload *ops;
 327         struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
 328         int err = -ENOSYS;
 329
 330         if (skb->encapsulation) {
 331                 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
 332                 skb_set_inner_network_header(skb, nhoff);
 333         }
 334
 335         iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
 336
 337         rcu_read_lock();
 338
 339         nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
 340         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
 341                 goto out_unlock;
 342
 343         err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
 344                                udp6_gro_complete, skb, nhoff);
 345
 346 out_unlock:
 347         rcu_read_unlock();
 348
 349         return err;
 350 }
 351
 352 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
 353 {
 354         skb->encapsulation = 1;
 355         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
 356         return ipv6_gro_complete(skb, nhoff);
 357 }
 358
 359 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
 360 {
 361         skb->encapsulation = 1;
 362         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 363         return ipv6_gro_complete(skb, nhoff);
 364 }
 365
 366 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
 367 {
 368         skb->encapsulation = 1;
 369         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 370         return inet_gro_complete(skb, nhoff);
 371 }
 372
 373 static struct packet_offload ipv6_packet_offload __read_mostly = {
 374         .type = cpu_to_be16(ETH_P_IPV6),
 375         .callbacks = {
 376                 .gso_segment = ipv6_gso_segment,
 377                 .gro_receive = ipv6_gro_receive,
 378                 .gro_complete = ipv6_gro_complete,
 379         },
 380 };
 381
 382 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
 383                                        netdev_features_t features)
 384 {
 385         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
 386                 return ERR_PTR(-EINVAL);
 387
 388         return ipv6_gso_segment(skb, features);
 389 }
 390
 391 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
 392                                           netdev_features_t features)
 393 {
 394         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 395                 return ERR_PTR(-EINVAL);
 396
 397         return inet_gso_segment(skb, features);
 398 }
 399
 400 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
 401                                           netdev_features_t features)
 402 {
 403         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 404                 return ERR_PTR(-EINVAL);
 405
 406         return ipv6_gso_segment(skb, features);
 407 }
 408
 409 static const struct net_offload sit_offload = {
 410         .callbacks = {
 411                 .gso_segment    = sit_gso_segment,
 412                 .gro_receive    = sit_ip6ip6_gro_receive,
 413                 .gro_complete   = sit_gro_complete,
 414         },
 415 };
 416
 417 static const struct net_offload ip4ip6_offload = {
 418         .callbacks = {
 419                 .gso_segment    = ip4ip6_gso_segment,
 420                 .gro_receive    = ip4ip6_gro_receive,
 421                 .gro_complete   = ip4ip6_gro_complete,
 422         },
 423 };
 424
 425 static const struct net_offload ip6ip6_offload = {
 426         .callbacks = {
 427                 .gso_segment    = ip6ip6_gso_segment,
 428                 .gro_receive    = sit_ip6ip6_gro_receive,
 429                 .gro_complete   = ip6ip6_gro_complete,
 430         },
 431 };
 432 static int __init ipv6_offload_init(void)
 433 {
 434
 435         if (tcpv6_offload_init() < 0)
 436                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
 437         if (ipv6_exthdrs_offload_init() < 0)
 438                 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
 439
 440         dev_add_offload(&ipv6_packet_offload);
 441
 442         inet_add_offload(&sit_offload, IPPROTO_IPV6);
 443         inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
 444         inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
 445
 446         return 0;
 447 }
 448
 449 fs_initcall(ipv6_offload_init);