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