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                 if (!segs)
 118                         skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
 119         }
 120
 121         if (IS_ERR_OR_NULL(segs))
 122                 goto out;
 123
 124         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
 125
 126         for (skb = segs; skb; skb = skb->next) {
 127                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
 128                 if (gso_partial && skb_is_gso(skb))
 129                         payload_len = skb_shinfo(skb)->gso_size +
 130                                       SKB_GSO_CB(skb)->data_offset +
 131                                       skb->head - (unsigned char *)(ipv6h + 1);
 132                 else
 133                         payload_len = skb->len - nhoff - sizeof(*ipv6h);
 134                 ipv6h->payload_len = htons(payload_len);
 135                 skb->network_header = (u8 *)ipv6h - skb->head;
 136                 skb_reset_mac_len(skb);
 137
 138                 if (udpfrag) {
 139                         int err = ip6_find_1stfragopt(skb, &prevhdr);
 140                         if (err < 0) {
 141                                 kfree_skb_list(segs);
 142                                 return ERR_PTR(err);
 143                         }
 144                         fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
 145                         fptr->frag_off = htons(offset);
 146                         if (skb->next)
 147                                 fptr->frag_off |= htons(IP6_MF);
 148                         offset += (ntohs(ipv6h->payload_len) -
 149                                    sizeof(struct frag_hdr));
 150                 }
 151                 if (encap)
 152                         skb_reset_inner_headers(skb);
 153         }
 154
 155 out:
 156         return segs;
 157 }
 158
 159 /* Return the total length of all the extension hdrs, following the same
 160  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
 161  */
 162 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
 163                             const struct net_offload **opps)
 164 {
 165         struct ipv6_opt_hdr *opth = (void *)iph;
 166         int len = 0, proto, optlen = sizeof(*iph);
 167
 168         proto = iph->nexthdr;
 169         for (;;) {
 170                 if (proto != NEXTHDR_HOP) {
 171                         *opps = rcu_dereference(inet6_offloads[proto]);
 172                         if (unlikely(!(*opps)))
 173                                 break;
 174                         if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
 175                                 break;
 176                 }
 177                 opth = (void *)opth + optlen;
 178                 optlen = ipv6_optlen(opth);
 179                 len += optlen;
 180                 proto = opth->nexthdr;
 181         }
 182         return len;
 183 }
 184
 185 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
 186                                                          struct sk_buff *skb)
 187 {
 188         const struct net_offload *ops;
 189         struct sk_buff *pp = NULL;
 190         struct sk_buff *p;
 191         struct ipv6hdr *iph;
 192         unsigned int nlen;
 193         unsigned int hlen;
 194         unsigned int off;
 195         u16 flush = 1;
 196         int proto;
 197
 198         off = skb_gro_offset(skb);
 199         hlen = off + sizeof(*iph);
 200         iph = skb_gro_header_fast(skb, off);
 201         if (skb_gro_header_hard(skb, hlen)) {
 202                 iph = skb_gro_header_slow(skb, hlen, off);
 203                 if (unlikely(!iph))
 204                         goto out;
 205         }
 206
 207         skb_set_network_header(skb, off);
 208         skb_gro_pull(skb, sizeof(*iph));
 209         skb_set_transport_header(skb, skb_gro_offset(skb));
 210
 211         flush += ntohs(iph->payload_len) != skb_gro_len(skb);
 212
 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;
 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:
 284         skb_gro_flush_final(skb, pp, flush);
 285
 286         return pp;
 287 }
 288
 289 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
 290                                               struct sk_buff *skb)
 291 {
 292         /* Common GRO receive for SIT and IP6IP6 */
 293
 294         if (NAPI_GRO_CB(skb)->encap_mark) {
 295                 NAPI_GRO_CB(skb)->flush = 1;
 296                 return NULL;
 297         }
 298
 299         NAPI_GRO_CB(skb)->encap_mark = 1;
 300
 301         return ipv6_gro_receive(head, skb);
 302 }
 303
 304 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
 305                                           struct sk_buff *skb)
 306 {
 307         /* Common GRO receive for SIT and IP6IP6 */
 308
 309         if (NAPI_GRO_CB(skb)->encap_mark) {
 310                 NAPI_GRO_CB(skb)->flush = 1;
 311                 return NULL;
 312         }
 313
 314         NAPI_GRO_CB(skb)->encap_mark = 1;
 315
 316         return inet_gro_receive(head, skb);
 317 }
 318
 319 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
 320 {
 321         const struct net_offload *ops;
 322         struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
 323         int err = -ENOSYS;
 324
 325         if (skb->encapsulation) {
 326                 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
 327                 skb_set_inner_network_header(skb, nhoff);
 328         }
 329
 330         iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
 331
 332         nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
 333         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
 334                 goto out;
 335
 336         err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
 337                                udp6_gro_complete, skb, nhoff);
 338
 339 out:
 340         return err;
 341 }
 342
 343 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
 344 {
 345         skb->encapsulation = 1;
 346         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
 347         return ipv6_gro_complete(skb, nhoff);
 348 }
 349
 350 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
 351 {
 352         skb->encapsulation = 1;
 353         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 354         return ipv6_gro_complete(skb, nhoff);
 355 }
 356
 357 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
 358 {
 359         skb->encapsulation = 1;
 360         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 361         return inet_gro_complete(skb, nhoff);
 362 }
 363
 364 static struct packet_offload ipv6_packet_offload __read_mostly = {
 365         .type = cpu_to_be16(ETH_P_IPV6),
 366         .callbacks = {
 367                 .gso_segment = ipv6_gso_segment,
 368                 .gro_receive = ipv6_gro_receive,
 369                 .gro_complete = ipv6_gro_complete,
 370         },
 371 };
 372
 373 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
 374                                        netdev_features_t features)
 375 {
 376         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
 377                 return ERR_PTR(-EINVAL);
 378
 379         return ipv6_gso_segment(skb, features);
 380 }
 381
 382 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
 383                                           netdev_features_t features)
 384 {
 385         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
 386                 return ERR_PTR(-EINVAL);
 387
 388         return inet_gso_segment(skb, features);
 389 }
 390
 391 static struct sk_buff *ip6ip6_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 ipv6_gso_segment(skb, features);
 398 }
 399
 400 static const struct net_offload sit_offload = {
 401         .callbacks = {
 402                 .gso_segment    = sit_gso_segment,
 403                 .gro_receive    = sit_ip6ip6_gro_receive,
 404                 .gro_complete   = sit_gro_complete,
 405         },
 406 };
 407
 408 static const struct net_offload ip4ip6_offload = {
 409         .callbacks = {
 410                 .gso_segment    = ip4ip6_gso_segment,
 411                 .gro_receive    = ip4ip6_gro_receive,
 412                 .gro_complete   = ip4ip6_gro_complete,
 413         },
 414 };
 415
 416 static const struct net_offload ip6ip6_offload = {
 417         .callbacks = {
 418                 .gso_segment    = ip6ip6_gso_segment,
 419                 .gro_receive    = sit_ip6ip6_gro_receive,
 420                 .gro_complete   = ip6ip6_gro_complete,
 421         },
 422 };
 423 static int __init ipv6_offload_init(void)
 424 {
 425
 426         if (tcpv6_offload_init() < 0)
 427                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
 428         if (ipv6_exthdrs_offload_init() < 0)
 429                 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
 430
 431         dev_add_offload(&ipv6_packet_offload);
 432
 433         inet_add_offload(&sit_offload, IPPROTO_IPV6);
 434         inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
 435         inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
 436
 437         return 0;
 438 }
 439
 440 fs_initcall(ipv6_offload_init);