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_gso_pull_exthdrs(struct sk_buff *skb, int proto)
  41 {
  42         const struct net_offload *ops = NULL;
  43
  44         for (;;) {
  45                 struct ipv6_opt_hdr *opth;
  46                 int len;
  47
  48                 if (proto != NEXTHDR_HOP) {
  49                         ops = rcu_dereference(inet6_offloads[proto]);
  50
  51                         if (unlikely(!ops))
  52                                 break;
  53
  54                         if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
  55                                 break;
  56                 }
  57
  58                 if (unlikely(!pskb_may_pull(skb, 8)))
  59                         break;
  60
  61                 opth = (void *)skb->data;
  62                 len = ipv6_optlen(opth);
  63
  64                 if (unlikely(!pskb_may_pull(skb, len)))
  65                         break;
  66
  67                 opth = (void *)skb->data;
  68                 proto = opth->nexthdr;
  69                 __skb_pull(skb, len);
  70         }
  71
  72         return proto;
  73 }
  74
  75 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
  76         netdev_features_t features)
  77 {
  78         struct sk_buff *segs = ERR_PTR(-EINVAL);
  79         struct ipv6hdr *ipv6h;
  80         const struct net_offload *ops;
  81         int proto, err;
  82         struct frag_hdr *fptr;
  83         unsigned int payload_len;
  84         u8 *prevhdr;
  85         int offset = 0;
  86         bool encap, udpfrag;
  87         int nhoff;
  88         bool gso_partial;
  89
  90         skb_reset_network_header(skb);
  91         err = ipv6_hopopt_jumbo_remove(skb);
  92         if (err)
  93                 return ERR_PTR(err);
  94         nhoff = skb_network_header(skb) - skb_mac_header(skb);
  95         if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
  96                 goto out;
  97
  98         encap = SKB_GSO_CB(skb)->encap_level > 0;
  99         if (encap)
 100                 features &= skb->dev->hw_enc_features;
 101         SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
 102
 103         ipv6h = ipv6_hdr(skb);
 104         __skb_pull(skb, sizeof(*ipv6h));
 105         segs = ERR_PTR(-EPROTONOSUPPORT);
 106
 107         proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
 108
 109         if (skb->encapsulation &&
 110             skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
 111                 udpfrag = proto == IPPROTO_UDP && encap &&
 112                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 113         else
 114                 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
 115                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 116
 117         ops = rcu_dereference(inet6_offloads[proto]);
 118         if (likely(ops && ops->callbacks.gso_segment)) {
 119                 skb_reset_transport_header(skb);
 120                 segs = ops->callbacks.gso_segment(skb, features);
 121                 if (!segs)
 122                         skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
 123         }
 124
 125         if (IS_ERR_OR_NULL(segs))
 126                 goto out;
 127
 128         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
 129
 130         for (skb = segs; skb; skb = skb->next) {
 131                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
 132                 if (gso_partial && skb_is_gso(skb))
 133                         payload_len = skb_shinfo(skb)->gso_size +
 134                                       SKB_GSO_CB(skb)->data_offset +
 135                                       skb->head - (unsigned char *)(ipv6h + 1);
 136                 else
 137                         payload_len = skb->len - nhoff - sizeof(*ipv6h);
 138                 ipv6h->payload_len = htons(payload_len);
 139                 skb->network_header = (u8 *)ipv6h - skb->head;
 140                 skb_reset_mac_len(skb);
 141
 142                 if (udpfrag) {
 143                         int err = ip6_find_1stfragopt(skb, &prevhdr);
 144                         if (err < 0) {
 145                                 kfree_skb_list(segs);
 146                                 return ERR_PTR(err);
 147                         }
 148                         fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
 149                         fptr->frag_off = htons(offset);
 150                         if (skb->next)
 151                                 fptr->frag_off |= htons(IP6_MF);
 152                         offset += (ntohs(ipv6h->payload_len) -
 153                                    sizeof(struct frag_hdr));
 154                 }
 155                 if (encap)
 156                         skb_reset_inner_headers(skb);
 157         }
 158
 159 out:
 160         return segs;
 161 }
 162
 163 /* Return the total length of all the extension hdrs, following the same
 164  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
 165  */
 166 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
 167                             const struct net_offload **opps)
 168 {
 169         struct ipv6_opt_hdr *opth = (void *)iph;
 170         int len = 0, proto, optlen = sizeof(*iph);
 171
 172         proto = iph->nexthdr;
 173         for (;;) {
 174                 if (proto != NEXTHDR_HOP) {
 175                         *opps = rcu_dereference(inet6_offloads[proto]);
 176                         if (unlikely(!(*opps)))
 177                                 break;
 178                         if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
 179                                 break;
 180                 }
 181                 opth = (void *)opth + optlen;
 182                 optlen = ipv6_optlen(opth);
 183                 len += optlen;
 184                 proto = opth->nexthdr;
 185         }
 186         return len;
 187 }
 188
 189 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
 190                                                          struct sk_buff *skb)
 191 {
 192         const struct net_offload *ops;
 193         struct sk_buff *pp = NULL;
 194         struct sk_buff *p;
 195         struct ipv6hdr *iph;
 196         unsigned int nlen;
 197         unsigned int hlen;
 198         unsigned int off;
 199         u16 flush = 1;
 200         int proto;
 201
 202         off = skb_gro_offset(skb);
 203         hlen = off + sizeof(*iph);
 204         iph = skb_gro_header(skb, hlen, off);
 205         if (unlikely(!iph))
 206                 goto out;
 207
 208         skb_set_network_header(skb, off);
 209         skb_gro_pull(skb, sizeof(*iph));
 210         skb_set_transport_header(skb, skb_gro_offset(skb));
 211
 212         flush += ntohs(iph->payload_len) != skb_gro_len(skb);
 213
 214         proto = iph->nexthdr;
 215         ops = rcu_dereference(inet6_offloads[proto]);
 216         if (!ops || !ops->callbacks.gro_receive) {
 217                 pskb_pull(skb, skb_gro_offset(skb));
 218                 skb_gro_frag0_invalidate(skb);
 219                 proto = ipv6_gso_pull_exthdrs(skb, proto);
 220                 skb_gro_pull(skb, -skb_transport_offset(skb));
 221                 skb_reset_transport_header(skb);
 222                 __skb_push(skb, skb_gro_offset(skb));
 223
 224                 ops = rcu_dereference(inet6_offloads[proto]);
 225                 if (!ops || !ops->callbacks.gro_receive)
 226                         goto out;
 227
 228                 iph = ipv6_hdr(skb);
 229         }
 230
 231         NAPI_GRO_CB(skb)->proto = proto;
 232
 233         flush--;
 234         nlen = skb_network_header_len(skb);
 235
 236         list_for_each_entry(p, head, list) {
 237                 const struct ipv6hdr *iph2;
 238                 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
 239
 240                 if (!NAPI_GRO_CB(p)->same_flow)
 241                         continue;
 242
 243                 iph2 = (struct ipv6hdr *)(p->data + off);
 244                 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
 245
 246                 /* All fields must match except length and Traffic Class.
 247                  * XXX skbs on the gro_list have all been parsed and pulled
 248                  * already so we don't need to compare nlen
 249                  * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
 250                  * memcmp() alone below is sufficient, right?
 251                  */
 252                  if ((first_word & htonl(0xF00FFFFF)) ||
 253                      !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
 254                      !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
 255                      iph->nexthdr != iph2->nexthdr) {
 256 not_same_flow:
 257                         NAPI_GRO_CB(p)->same_flow = 0;
 258                         continue;
 259                 }
 260                 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
 261                         if (memcmp(iph + 1, iph2 + 1,
 262                                    nlen - sizeof(struct ipv6hdr)))
 263                                 goto not_same_flow;
 264                 }
 265                 /* flush if Traffic Class fields are different */
 266                 NAPI_GRO_CB(p)->flush |= !!((first_word & htonl(0x0FF00000)) |
 267                         (__force __be32)(iph->hop_limit ^ iph2->hop_limit));
 268                 NAPI_GRO_CB(p)->flush |= flush;
 269
 270                 /* If the previous IP ID value was based on an atomic
 271                  * datagram we can overwrite the value and ignore it.
 272                  */
 273                 if (NAPI_GRO_CB(skb)->is_atomic)
 274                         NAPI_GRO_CB(p)->flush_id = 0;
 275         }
 276
 277         NAPI_GRO_CB(skb)->is_atomic = true;
 278         NAPI_GRO_CB(skb)->flush |= flush;
 279
 280         skb_gro_postpull_rcsum(skb, iph, nlen);
 281
 282         pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
 283                                          ops->callbacks.gro_receive, head, skb);
 284
 285 out:
 286         skb_gro_flush_final(skb, pp, flush);
 287
 288         return pp;
 289 }
 290
 291 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
 292                                               struct sk_buff *skb)
 293 {
 294         /* Common GRO receive for SIT and IP6IP6 */
 295
 296         if (NAPI_GRO_CB(skb)->encap_mark) {
 297                 NAPI_GRO_CB(skb)->flush = 1;
 298                 return NULL;
 299         }
 300
 301         NAPI_GRO_CB(skb)->encap_mark = 1;
 302
 303         return ipv6_gro_receive(head, skb);
 304 }
 305
 306 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
 307                                           struct sk_buff *skb)
 308 {
 309         /* Common GRO receive for SIT and IP6IP6 */
 310
 311         if (NAPI_GRO_CB(skb)->encap_mark) {
 312                 NAPI_GRO_CB(skb)->flush = 1;
 313                 return NULL;
 314         }
 315
 316         NAPI_GRO_CB(skb)->encap_mark = 1;
 317
 318         return inet_gro_receive(head, skb);
 319 }
 320
 321 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
 322 {
 323         const struct net_offload *ops;
 324         struct ipv6hdr *iph;
 325         int err = -ENOSYS;
 326         u32 payload_len;
 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         payload_len = skb->len - nhoff - sizeof(*iph);
 334         if (unlikely(payload_len > IPV6_MAXPLEN)) {
 335                 struct hop_jumbo_hdr *hop_jumbo;
 336                 int hoplen = sizeof(*hop_jumbo);
 337
 338                 /* Move network header left */
 339                 memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb),
 340                         skb->transport_header - skb->mac_header);
 341                 skb->data -= hoplen;
 342                 skb->len += hoplen;
 343                 skb->mac_header -= hoplen;
 344                 skb->network_header -= hoplen;
 345                 iph = (struct ipv6hdr *)(skb->data + nhoff);
 346                 hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1);
 347
 348                 /* Build hop-by-hop options */
 349                 hop_jumbo->nexthdr = iph->nexthdr;
 350                 hop_jumbo->hdrlen = 0;
 351                 hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
 352                 hop_jumbo->tlv_len = 4;
 353                 hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen);
 354
 355                 iph->nexthdr = NEXTHDR_HOP;
 356                 iph->payload_len = 0;
 357         } else {
 358                 iph = (struct ipv6hdr *)(skb->data + nhoff);
 359                 iph->payload_len = htons(payload_len);
 360         }
 361
 362         nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
 363         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
 364                 goto out;
 365
 366         err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
 367                                udp6_gro_complete, skb, nhoff);
 368
 369 out:
 370         return err;
 371 }
 372
 373 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
 374 {
 375         skb->encapsulation = 1;
 376         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
 377         return ipv6_gro_complete(skb, nhoff);
 378 }
 379
 380 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
 381 {
 382         skb->encapsulation = 1;
 383         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 384         return ipv6_gro_complete(skb, nhoff);
 385 }
 386
 387 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
 388 {
 389         skb->encapsulation = 1;
 390         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 391         return inet_gro_complete(skb, nhoff);
 392 }
 393
 394 static struct packet_offload ipv6_packet_offload __read_mostly = {
 395         .type = cpu_to_be16(ETH_P_IPV6),
 396         .callbacks = {
 397                 .gso_segment = ipv6_gso_segment,
 398                 .gro_receive = ipv6_gro_receive,
 399                 .gro_complete = ipv6_gro_complete,
 400         },
 401 };
 402
 403 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
 404                                        netdev_features_t features)
 405 {
 406         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
 407                 return ERR_PTR(-EINVAL);
 408
 409         return ipv6_gso_segment(skb, features);
 410 }
 411
 412 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
 413                                           netdev_features_t features)
 414 {
 415         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 416                 return ERR_PTR(-EINVAL);
 417
 418         return inet_gso_segment(skb, features);
 419 }
 420
 421 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
 422                                           netdev_features_t features)
 423 {
 424         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 425                 return ERR_PTR(-EINVAL);
 426
 427         return ipv6_gso_segment(skb, features);
 428 }
 429
 430 static const struct net_offload sit_offload = {
 431         .callbacks = {
 432                 .gso_segment    = sit_gso_segment,
 433                 .gro_receive    = sit_ip6ip6_gro_receive,
 434                 .gro_complete   = sit_gro_complete,
 435         },
 436 };
 437
 438 static const struct net_offload ip4ip6_offload = {
 439         .callbacks = {
 440                 .gso_segment    = ip4ip6_gso_segment,
 441                 .gro_receive    = ip4ip6_gro_receive,
 442                 .gro_complete   = ip4ip6_gro_complete,
 443         },
 444 };
 445
 446 static const struct net_offload ip6ip6_offload = {
 447         .callbacks = {
 448                 .gso_segment    = ip6ip6_gso_segment,
 449                 .gro_receive    = sit_ip6ip6_gro_receive,
 450                 .gro_complete   = ip6ip6_gro_complete,
 451         },
 452 };
 453 static int __init ipv6_offload_init(void)
 454 {
 455
 456         if (tcpv6_offload_init() < 0)
 457                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
 458         if (ipv6_exthdrs_offload_init() < 0)
 459                 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
 460
 461         dev_add_offload(&ipv6_packet_offload);
 462
 463         inet_add_offload(&sit_offload, IPPROTO_IPV6);
 464         inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
 465         inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
 466
 467         return 0;
 468 }
 469
 470 fs_initcall(ipv6_offload_init);