net/ipv6/ip6_offload.c

   1 /*
   2  *      IPV6 GSO/GRO offload support
   3  *      Linux INET6 implementation
   4  *
   5  *      This program is free software; you can redistribute it and/or
   6  *      modify it under the terms of the GNU General Public License
   7  *      as published by the Free Software Foundation; either version
   8  *      2 of the License, or (at your option) any later version.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/socket.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/printk.h>
  16
  17 #include <net/protocol.h>
  18 #include <net/ipv6.h>
  19 #include <net/inet_common.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;
  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         nhoff = skb_network_header(skb) - skb_mac_header(skb);
  92         if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
  93                 goto out;
  94
  95         encap = SKB_GSO_CB(skb)->encap_level > 0;
  96         if (encap)
  97                 features &= skb->dev->hw_enc_features;
  98         SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
  99
 100         ipv6h = ipv6_hdr(skb);
 101         __skb_pull(skb, sizeof(*ipv6h));
 102         segs = ERR_PTR(-EPROTONOSUPPORT);
 103
 104         proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
 105
 106         if (skb->encapsulation &&
 107             skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
 108                 udpfrag = proto == IPPROTO_UDP && encap &&
 109                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 110         else
 111                 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
 112                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 113
 114         ops = rcu_dereference(inet6_offloads[proto]);
 115         if (likely(ops && ops->callbacks.gso_segment)) {
 116                 skb_reset_transport_header(skb);
 117                 segs = ops->callbacks.gso_segment(skb, features);
 118         }
 119
 120         if (IS_ERR_OR_NULL(segs))
 121                 goto out;
 122
 123         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
 124
 125         for (skb = segs; skb; skb = skb->next) {
 126                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
 127                 if (gso_partial && skb_is_gso(skb))
 128                         payload_len = skb_shinfo(skb)->gso_size +
 129                                       SKB_GSO_CB(skb)->data_offset +
 130                                       skb->head - (unsigned char *)(ipv6h + 1);
 131                 else
 132                         payload_len = skb->len - nhoff - sizeof(*ipv6h);
 133                 ipv6h->payload_len = htons(payload_len);
 134                 skb->network_header = (u8 *)ipv6h - skb->head;
 135                 skb_reset_mac_len(skb);
 136
 137                 if (udpfrag) {
 138                         int err = ip6_find_1stfragopt(skb, &prevhdr);
 139                         if (err < 0) {
 140                                 kfree_skb_list(segs);
 141                                 return ERR_PTR(err);
 142                         }
 143                         fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
 144                         fptr->frag_off = htons(offset);
 145                         if (skb->next)
 146                                 fptr->frag_off |= htons(IP6_MF);
 147                         offset += (ntohs(ipv6h->payload_len) -
 148                                    sizeof(struct frag_hdr));
 149                 }
 150                 if (encap)
 151                         skb_reset_inner_headers(skb);
 152         }
 153
 154 out:
 155         return segs;
 156 }
 157
 158 /* Return the total length of all the extension hdrs, following the same
 159  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
 160  */
 161 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
 162                             const struct net_offload **opps)
 163 {
 164         struct ipv6_opt_hdr *opth = (void *)iph;
 165         int len = 0, proto, optlen = sizeof(*iph);
 166
 167         proto = iph->nexthdr;
 168         for (;;) {
 169                 if (proto != NEXTHDR_HOP) {
 170                         *opps = rcu_dereference(inet6_offloads[proto]);
 171                         if (unlikely(!(*opps)))
 172                                 break;
 173                         if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
 174                                 break;
 175                 }
 176                 opth = (void *)opth + optlen;
 177                 optlen = ipv6_optlen(opth);
 178                 len += optlen;
 179                 proto = opth->nexthdr;
 180         }
 181         return len;
 182 }
 183
 184 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *,
 185                                                            struct sk_buff *));
 186 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *,
 187                                                            struct sk_buff *));
 188 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
 189                                                          struct sk_buff *skb)
 190 {
 191         const struct net_offload *ops;
 192         struct sk_buff *pp = NULL;
 193         struct sk_buff *p;
 194         struct ipv6hdr *iph;
 195         unsigned int nlen;
 196         unsigned int hlen;
 197         unsigned int off;
 198         u16 flush = 1;
 199         int proto;
 200
 201         off = skb_gro_offset(skb);
 202         hlen = off + sizeof(*iph);
 203         iph = skb_gro_header_fast(skb, off);
 204         if (skb_gro_header_hard(skb, hlen)) {
 205                 iph = skb_gro_header_slow(skb, hlen, off);
 206                 if (unlikely(!iph))
 207                         goto out;
 208         }
 209
 210         skb_set_network_header(skb, off);
 211         skb_gro_pull(skb, sizeof(*iph));
 212         skb_set_transport_header(skb, skb_gro_offset(skb));
 213
 214         flush += ntohs(iph->payload_len) != skb_gro_len(skb);
 215
 216         rcu_read_lock();
 217         proto = iph->nexthdr;
 218         ops = rcu_dereference(inet6_offloads[proto]);
 219         if (!ops || !ops->callbacks.gro_receive) {
 220                 __pskb_pull(skb, skb_gro_offset(skb));
 221                 skb_gro_frag0_invalidate(skb);
 222                 proto = ipv6_gso_pull_exthdrs(skb, proto);
 223                 skb_gro_pull(skb, -skb_transport_offset(skb));
 224                 skb_reset_transport_header(skb);
 225                 __skb_push(skb, skb_gro_offset(skb));
 226
 227                 ops = rcu_dereference(inet6_offloads[proto]);
 228                 if (!ops || !ops->callbacks.gro_receive)
 229                         goto out_unlock;
 230
 231                 iph = ipv6_hdr(skb);
 232         }
 233
 234         NAPI_GRO_CB(skb)->proto = proto;
 235
 236         flush--;
 237         nlen = skb_network_header_len(skb);
 238
 239         list_for_each_entry(p, head, list) {
 240                 const struct ipv6hdr *iph2;
 241                 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
 242
 243                 if (!NAPI_GRO_CB(p)->same_flow)
 244                         continue;
 245
 246                 iph2 = (struct ipv6hdr *)(p->data + off);
 247                 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
 248
 249                 /* All fields must match except length and Traffic Class.
 250                  * XXX skbs on the gro_list have all been parsed and pulled
 251                  * already so we don't need to compare nlen
 252                  * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
 253                  * memcmp() alone below is sufficient, right?
 254                  */
 255                  if ((first_word & htonl(0xF00FFFFF)) ||
 256                     !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
 257                     !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
 258                     *(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) {
 259 not_same_flow:
 260                         NAPI_GRO_CB(p)->same_flow = 0;
 261                         continue;
 262                 }
 263                 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
 264                         if (memcmp(iph + 1, iph2 + 1,
 265                                    nlen - sizeof(struct ipv6hdr)))
 266                                 goto not_same_flow;
 267                 }
 268                 /* flush if Traffic Class fields are different */
 269                 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
 270                 NAPI_GRO_CB(p)->flush |= flush;
 271
 272                 /* If the previous IP ID value was based on an atomic
 273                  * datagram we can overwrite the value and ignore it.
 274                  */
 275                 if (NAPI_GRO_CB(skb)->is_atomic)
 276                         NAPI_GRO_CB(p)->flush_id = 0;
 277         }
 278
 279         NAPI_GRO_CB(skb)->is_atomic = true;
 280         NAPI_GRO_CB(skb)->flush |= flush;
 281
 282         skb_gro_postpull_rcsum(skb, iph, nlen);
 283
 284         pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
 285                                          ops->callbacks.gro_receive, head, skb);
 286
 287 out_unlock:
 288         rcu_read_unlock();
 289
 290 out:
 291         skb_gro_flush_final(skb, pp, flush);
 292
 293         return pp;
 294 }
 295
 296 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
 297                                               struct sk_buff *skb)
 298 {
 299         /* Common GRO receive for SIT and IP6IP6 */
 300
 301         if (NAPI_GRO_CB(skb)->encap_mark) {
 302                 NAPI_GRO_CB(skb)->flush = 1;
 303                 return NULL;
 304         }
 305
 306         NAPI_GRO_CB(skb)->encap_mark = 1;
 307
 308         return ipv6_gro_receive(head, skb);
 309 }
 310
 311 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
 312                                           struct sk_buff *skb)
 313 {
 314         /* Common GRO receive for SIT and IP6IP6 */
 315
 316         if (NAPI_GRO_CB(skb)->encap_mark) {
 317                 NAPI_GRO_CB(skb)->flush = 1;
 318                 return NULL;
 319         }
 320
 321         NAPI_GRO_CB(skb)->encap_mark = 1;
 322
 323         return inet_gro_receive(head, skb);
 324 }
 325
 326 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *, int));
 327 INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int));
 328 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
 329 {
 330         const struct net_offload *ops;
 331         struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
 332         int err = -ENOSYS;
 333
 334         if (skb->encapsulation) {
 335                 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
 336                 skb_set_inner_network_header(skb, nhoff);
 337         }
 338
 339         iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
 340
 341         rcu_read_lock();
 342
 343         nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
 344         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
 345                 goto out_unlock;
 346
 347         err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
 348                                udp6_gro_complete, skb, nhoff);
 349
 350 out_unlock:
 351         rcu_read_unlock();
 352
 353         return err;
 354 }
 355
 356 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
 357 {
 358         skb->encapsulation = 1;
 359         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
 360         return ipv6_gro_complete(skb, nhoff);
 361 }
 362
 363 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
 364 {
 365         skb->encapsulation = 1;
 366         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 367         return ipv6_gro_complete(skb, nhoff);
 368 }
 369
 370 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
 371 {
 372         skb->encapsulation = 1;
 373         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
 374         return inet_gro_complete(skb, nhoff);
 375 }
 376
 377 static struct packet_offload ipv6_packet_offload __read_mostly = {
 378         .type = cpu_to_be16(ETH_P_IPV6),
 379         .callbacks = {
 380                 .gso_segment = ipv6_gso_segment,
 381                 .gro_receive = ipv6_gro_receive,
 382                 .gro_complete = ipv6_gro_complete,
 383         },
 384 };
 385
 386 static const struct net_offload sit_offload = {
 387         .callbacks = {
 388                 .gso_segment    = ipv6_gso_segment,
 389                 .gro_receive    = sit_ip6ip6_gro_receive,
 390                 .gro_complete   = sit_gro_complete,
 391         },
 392 };
 393
 394 static const struct net_offload ip4ip6_offload = {
 395         .callbacks = {
 396                 .gso_segment    = inet_gso_segment,
 397                 .gro_receive    = ip4ip6_gro_receive,
 398                 .gro_complete   = ip4ip6_gro_complete,
 399         },
 400 };
 401
 402 static const struct net_offload ip6ip6_offload = {
 403         .callbacks = {
 404                 .gso_segment    = ipv6_gso_segment,
 405                 .gro_receive    = sit_ip6ip6_gro_receive,
 406                 .gro_complete   = ip6ip6_gro_complete,
 407         },
 408 };
 409 static int __init ipv6_offload_init(void)
 410 {
 411
 412         if (tcpv6_offload_init() < 0)
 413                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
 414         if (ipv6_exthdrs_offload_init() < 0)
 415                 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
 416
 417         dev_add_offload(&ipv6_packet_offload);
 418
 419         inet_add_offload(&sit_offload, IPPROTO_IPV6);
 420         inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
 421         inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
 422
 423         return 0;
 424 }
 425
 426 fs_initcall(ipv6_offload_init);