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 #include <net/gro.h>
  19 #include <net/gso.h>
  20
  21 #include "ip6_offload.h"
  22
  23 /* All GRO functions are always builtin, except UDP over ipv6, which lays in
  24  * ipv6 module, as it depends on UDPv6 lookup function, so we need special care
  25  * when ipv6 is built as a module
  26  */
  27 #if IS_BUILTIN(CONFIG_IPV6)
  28 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
  29 #else
  30 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
  31 #endif
  32
  33 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb)     \
  34 ({                                                              \
  35         unlikely(gro_recursion_inc_test(skb)) ?                 \
  36                 NAPI_GRO_CB(skb)->flush |= 1, NULL :            \
  37                 INDIRECT_CALL_L4(cb, f2, f1, head, skb);        \
  38 })
  39
  40 static int ipv6_gro_pull_exthdrs(struct sk_buff *skb, int off, int proto)
  41 {
  42         const struct net_offload *ops = NULL;
  43         struct ipv6_opt_hdr *opth;
  44
  45         for (;;) {
  46                 int len;
  47
  48                 ops = rcu_dereference(inet6_offloads[proto]);
  49
  50                 if (unlikely(!ops))
  51                         break;
  52
  53                 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
  54                         break;
  55
  56                 opth = skb_gro_header(skb, off + sizeof(*opth), off);
  57                 if (unlikely(!opth))
  58                         break;
  59
  60                 len = ipv6_optlen(opth);
  61
  62                 opth = skb_gro_header(skb, off + len, off);
  63                 if (unlikely(!opth))
  64                         break;
  65                 proto = opth->nexthdr;
  66
  67                 off += len;
  68         }
  69
  70         skb_gro_pull(skb, off - skb_network_offset(skb));
  71         return proto;
  72 }
  73
  74 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
  75 {
  76         const struct net_offload *ops = NULL;
  77
  78         for (;;) {
  79                 struct ipv6_opt_hdr *opth;
  80                 int len;
  81
  82                 ops = rcu_dereference(inet6_offloads[proto]);
  83
  84                 if (unlikely(!ops))
  85                         break;
  86
  87                 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
  88                         break;
  89
  90                 if (unlikely(!pskb_may_pull(skb, 8)))
  91                         break;
  92
  93                 opth = (void *)skb->data;
  94                 len = ipv6_optlen(opth);
  95
  96                 if (unlikely(!pskb_may_pull(skb, len)))
  97                         break;
  98
  99                 opth = (void *)skb->data;
 100                 proto = opth->nexthdr;
 101                 __skb_pull(skb, len);
 102         }
 103
 104         return proto;
 105 }
 106
 107 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
 108         netdev_features_t features)
 109 {
 110         struct sk_buff *segs = ERR_PTR(-EINVAL);
 111         struct ipv6hdr *ipv6h;
 112         const struct net_offload *ops;
 113         int proto, err;
 114         struct frag_hdr *fptr;
 115         unsigned int payload_len;
 116         u8 *prevhdr;
 117         int offset = 0;
 118         bool encap, udpfrag;
 119         int nhoff;
 120         bool gso_partial;
 121
 122         skb_reset_network_header(skb);
 123         err = ipv6_hopopt_jumbo_remove(skb);
 124         if (err)
 125                 return ERR_PTR(err);
 126         nhoff = skb_network_header(skb) - skb_mac_header(skb);
 127         if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
 128                 goto out;
 129
 130         encap = SKB_GSO_CB(skb)->encap_level > 0;
 131         if (encap)
 132                 features &= skb->dev->hw_enc_features;
 133         SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
 134
 135         ipv6h = ipv6_hdr(skb);
 136         __skb_pull(skb, sizeof(*ipv6h));
 137         segs = ERR_PTR(-EPROTONOSUPPORT);
 138
 139         proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
 140
 141         if (skb->encapsulation &&
 142             skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
 143                 udpfrag = proto == IPPROTO_UDP && encap &&
 144                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 145         else
 146                 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
 147                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 148
 149         ops = rcu_dereference(inet6_offloads[proto]);
 150         if (likely(ops && ops->callbacks.gso_segment)) {
 151                 skb_reset_transport_header(skb);
 152                 segs = ops->callbacks.gso_segment(skb, features);
 153                 if (!segs)
 154                         skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
 155         }
 156
 157         if (IS_ERR_OR_NULL(segs))
 158                 goto out;
 159
 160         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
 161
 162         for (skb = segs; skb; skb = skb->next) {
 163                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
 164                 if (gso_partial && skb_is_gso(skb))
 165                         payload_len = skb_shinfo(skb)->gso_size +
 166                                       SKB_GSO_CB(skb)->data_offset +
 167                                       skb->head - (unsigned char *)(ipv6h + 1);
 168                 else
 169                         payload_len = skb->len - nhoff - sizeof(*ipv6h);
 170                 ipv6h->payload_len = htons(payload_len);
 171                 skb->network_header = (u8 *)ipv6h - skb->head;
 172                 skb_reset_mac_len(skb);
 173
 174                 if (udpfrag) {
 175                         int err = ip6_find_1stfragopt(skb, &prevhdr);
 176                         if (err < 0) {
 177                                 kfree_skb_list(segs);
 178                                 return ERR_PTR(err);
 179                         }
 180                         fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
 181                         fptr->frag_off = htons(offset);
 182                         if (skb->next)
 183                                 fptr->frag_off |= htons(IP6_MF);
 184                         offset += (ntohs(ipv6h->payload_len) -
 185                                    sizeof(struct frag_hdr));
 186                 }
 187                 if (encap)
 188                         skb_reset_inner_headers(skb);
 189         }
 190
 191 out:
 192         return segs;
 193 }
 194
 195 /* Return the total length of all the extension hdrs, following the same
 196  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
 197  */
 198 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
 199                             const struct net_offload **opps)
 200 {
 201         struct ipv6_opt_hdr *opth = (void *)iph;
 202         int len = 0, proto, optlen = sizeof(*iph);
 203
 204         proto = iph->nexthdr;
 205         for (;;) {
 206                 *opps = rcu_dereference(inet6_offloads[proto]);
 207                 if (unlikely(!(*opps)))
 208                         break;
 209                 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
 210                         break;
 211
 212                 opth = (void *)opth + optlen;
 213                 optlen = ipv6_optlen(opth);
 214                 len += optlen;
 215                 proto = opth->nexthdr;
 216         }
 217         return len;
 218 }
 219
 220 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
 221                                                          struct sk_buff *skb)
 222 {
 223         const struct net_offload *ops;
 224         struct sk_buff *pp = NULL;
 225         struct sk_buff *p;
 226         struct ipv6hdr *iph;
 227         unsigned int nlen;
 228         unsigned int hlen;
 229         unsigned int off;
 230         u16 flush = 1;
 231         int proto;
 232
 233         off = skb_gro_offset(skb);
 234         hlen = off + sizeof(*iph);
 235         iph = skb_gro_header(skb, hlen, off);
 236         if (unlikely(!iph))
 237                 goto out;
 238
 239         skb_set_network_header(skb, off);
 240
 241         flush += ntohs(iph->payload_len) != skb->len - hlen;
 242
 243         proto = iph->nexthdr;
 244         ops = rcu_dereference(inet6_offloads[proto]);
 245         if (!ops || !ops->callbacks.gro_receive) {
 246                 proto = ipv6_gro_pull_exthdrs(skb, hlen, proto);
 247
 248                 ops = rcu_dereference(inet6_offloads[proto]);
 249                 if (!ops || !ops->callbacks.gro_receive)
 250                         goto out;
 251
 252                 iph = skb_gro_network_header(skb);
 253         } else {
 254                 skb_gro_pull(skb, sizeof(*iph));
 255         }
 256
 257         skb_set_transport_header(skb, skb_gro_offset(skb));
 258
 259         NAPI_GRO_CB(skb)->proto = proto;
 260
 261         flush--;
 262         nlen = skb_network_header_len(skb);
 263
 264         list_for_each_entry(p, head, list) {
 265                 const struct ipv6hdr *iph2;
 266                 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
 267
 268                 if (!NAPI_GRO_CB(p)->same_flow)
 269                         continue;
 270
 271                 iph2 = (struct ipv6hdr *)(p->data + off);
 272                 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
 273
 274                 /* All fields must match except length and Traffic Class.
 275                  * XXX skbs on the gro_list have all been parsed and pulled
 276                  * already so we don't need to compare nlen
 277                  * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
 278                  * memcmp() alone below is sufficient, right?
 279                  */
 280                  if ((first_word & htonl(0xF00FFFFF)) ||
 281                      !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
 282                      !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
 283                      iph->nexthdr != iph2->nexthdr) {
 284 not_same_flow:
 285                         NAPI_GRO_CB(p)->same_flow = 0;
 286                         continue;
 287                 }
 288                 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
 289                         if (memcmp(iph + 1, iph2 + 1,
 290                                    nlen - sizeof(struct ipv6hdr)))
 291                                 goto not_same_flow;
 292                 }
 293                 /* flush if Traffic Class fields are different */
 294                 NAPI_GRO_CB(p)->flush |= !!((first_word & htonl(0x0FF00000)) |
 295                         (__force __be32)(iph->hop_limit ^ iph2->hop_limit));
 296                 NAPI_GRO_CB(p)->flush |= flush;
 297
 298                 /* If the previous IP ID value was based on an atomic
 299                  * datagram we can overwrite the value and ignore it.
 300                  */
 301                 if (NAPI_GRO_CB(skb)->is_atomic)
 302                         NAPI_GRO_CB(p)->flush_id = 0;
 303         }
 304
 305         NAPI_GRO_CB(skb)->is_atomic = true;
 306         NAPI_GRO_CB(skb)->flush |= flush;
 307
 308         skb_gro_postpull_rcsum(skb, iph, nlen);
 309
 310         pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
 311                                          ops->callbacks.gro_receive, head, skb);
 312
 313 out:
 314         skb_gro_flush_final(skb, pp, flush);
 315
 316         return pp;
 317 }
 318
 319 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
 320                                               struct sk_buff *skb)
 321 {
 322         /* Common GRO receive for SIT and IP6IP6 */
 323
 324         if (NAPI_GRO_CB(skb)->encap_mark) {
 325                 NAPI_GRO_CB(skb)->flush = 1;
 326                 return NULL;
 327         }
 328
 329         NAPI_GRO_CB(skb)->encap_mark = 1;
 330
 331         return ipv6_gro_receive(head, skb);
 332 }
 333
 334 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
 335                                           struct sk_buff *skb)
 336 {
 337         /* Common GRO receive for SIT and IP6IP6 */
 338
 339         if (NAPI_GRO_CB(skb)->encap_mark) {
 340                 NAPI_GRO_CB(skb)->flush = 1;
 341                 return NULL;
 342         }
 343
 344         NAPI_GRO_CB(skb)->encap_mark = 1;
 345
 346         return inet_gro_receive(head, skb);
 347 }
 348
 349 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
 350 {
 351         const struct net_offload *ops;
 352         struct ipv6hdr *iph;
 353         int err = -ENOSYS;
 354         u32 payload_len;
 355
 356         if (skb->encapsulation) {
 357                 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
 358                 skb_set_inner_network_header(skb, nhoff);
 359         }
 360
 361         payload_len = skb->len - nhoff - sizeof(*iph);
 362         if (unlikely(payload_len > IPV6_MAXPLEN)) {
 363                 struct hop_jumbo_hdr *hop_jumbo;
 364                 int hoplen = sizeof(*hop_jumbo);
 365
 366                 /* Move network header left */
 367                 memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb),
 368                         skb->transport_header - skb->mac_header);
 369                 skb->data -= hoplen;
 370                 skb->len += hoplen;
 371                 skb->mac_header -= hoplen;
 372                 skb->network_header -= hoplen;
 373                 iph = (struct ipv6hdr *)(skb->data + nhoff);
 374                 hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1);
 375
 376                 /* Build hop-by-hop options */
 377                 hop_jumbo->nexthdr = iph->nexthdr;
 378                 hop_jumbo->hdrlen = 0;
 379                 hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
 380                 hop_jumbo->tlv_len = 4;
 381                 hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen);
 382
 383                 iph->nexthdr = NEXTHDR_HOP;
 384                 iph->payload_len = 0;
 385         } else {
 386                 iph = (struct ipv6hdr *)(skb->data + nhoff);
 387                 iph->payload_len = htons(payload_len);
 388         }
 389
 390         nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
 391         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
 392                 goto out;
 393
 394         err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
 395                                udp6_gro_complete, skb, nhoff);
 396
 397 out:
 398         return err;
 399 }
 400
 401 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
 402 {
 403         skb->encapsulation = 1;
 404         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
 405         return ipv6_gro_complete(skb, nhoff);
 406 }
 407
 408 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
 409 {
 410         skb->encapsulation = 1;
 411         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 412         return ipv6_gro_complete(skb, nhoff);
 413 }
 414
 415 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
 416 {
 417         skb->encapsulation = 1;
 418         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 419         return inet_gro_complete(skb, nhoff);
 420 }
 421
 422 static struct packet_offload ipv6_packet_offload __read_mostly = {
 423         .type = cpu_to_be16(ETH_P_IPV6),
 424         .callbacks = {
 425                 .gso_segment = ipv6_gso_segment,
 426                 .gro_receive = ipv6_gro_receive,
 427                 .gro_complete = ipv6_gro_complete,
 428         },
 429 };
 430
 431 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
 432                                        netdev_features_t features)
 433 {
 434         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
 435                 return ERR_PTR(-EINVAL);
 436
 437         return ipv6_gso_segment(skb, features);
 438 }
 439
 440 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
 441                                           netdev_features_t features)
 442 {
 443         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 444                 return ERR_PTR(-EINVAL);
 445
 446         return inet_gso_segment(skb, features);
 447 }
 448
 449 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
 450                                           netdev_features_t features)
 451 {
 452         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 453                 return ERR_PTR(-EINVAL);
 454
 455         return ipv6_gso_segment(skb, features);
 456 }
 457
 458 static const struct net_offload sit_offload = {
 459         .callbacks = {
 460                 .gso_segment    = sit_gso_segment,
 461                 .gro_receive    = sit_ip6ip6_gro_receive,
 462                 .gro_complete   = sit_gro_complete,
 463         },
 464 };
 465
 466 static const struct net_offload ip4ip6_offload = {
 467         .callbacks = {
 468                 .gso_segment    = ip4ip6_gso_segment,
 469                 .gro_receive    = ip4ip6_gro_receive,
 470                 .gro_complete   = ip4ip6_gro_complete,
 471         },
 472 };
 473
 474 static const struct net_offload ip6ip6_offload = {
 475         .callbacks = {
 476                 .gso_segment    = ip6ip6_gso_segment,
 477                 .gro_receive    = sit_ip6ip6_gro_receive,
 478                 .gro_complete   = ip6ip6_gro_complete,
 479         },
 480 };
 481 static int __init ipv6_offload_init(void)
 482 {
 483
 484         if (tcpv6_offload_init() < 0)
 485                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
 486         if (ipv6_exthdrs_offload_init() < 0)
 487                 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
 488
 489         dev_add_offload(&ipv6_packet_offload);
 490
 491         inet_add_offload(&sit_offload, IPPROTO_IPV6);
 492         inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
 493         inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
 494
 495         return 0;
 496 }
 497
 498 fs_initcall(ipv6_offload_init);