net/core/flow_dissector.c

   1 #include <linux/kernel.h>
   2 #include <linux/skbuff.h>
   3 #include <linux/export.h>
   4 #include <linux/ip.h>
   5 #include <linux/ipv6.h>
   6 #include <linux/if_vlan.h>
   7 #include <net/ip.h>
   8 #include <net/ipv6.h>
   9 #include <linux/igmp.h>
  10 #include <linux/icmp.h>
  11 #include <linux/sctp.h>
  12 #include <linux/dccp.h>
  13 #include <linux/if_tunnel.h>
  14 #include <linux/if_pppox.h>
  15 #include <linux/ppp_defs.h>
  16 #include <linux/stddef.h>
  17 #include <linux/if_ether.h>
  18 #include <linux/mpls.h>
  19 #include <net/flow_dissector.h>
  20 #include <scsi/fc/fc_fcoe.h>
  21
  22 static bool skb_flow_dissector_uses_key(struct flow_dissector *flow_dissector,
  23                                         enum flow_dissector_key_id key_id)
  24 {
  25         return flow_dissector->used_keys & (1 << key_id);
  26 }
  27
  28 static void skb_flow_dissector_set_key(struct flow_dissector *flow_dissector,
  29                                        enum flow_dissector_key_id key_id)
  30 {
  31         flow_dissector->used_keys |= (1 << key_id);
  32 }
  33
  34 static void *skb_flow_dissector_target(struct flow_dissector *flow_dissector,
  35                                        enum flow_dissector_key_id key_id,
  36                                        void *target_container)
  37 {
  38         return ((char *) target_container) + flow_dissector->offset[key_id];
  39 }
  40
  41 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
  42                              const struct flow_dissector_key *key,
  43                              unsigned int key_count)
  44 {
  45         unsigned int i;
  46
  47         memset(flow_dissector, 0, sizeof(*flow_dissector));
  48
  49         for (i = 0; i < key_count; i++, key++) {
  50                 /* User should make sure that every key target offset is withing
  51                  * boundaries of unsigned short.
  52                  */
  53                 BUG_ON(key->offset > USHRT_MAX);
  54                 BUG_ON(skb_flow_dissector_uses_key(flow_dissector,
  55                                                    key->key_id));
  56
  57                 skb_flow_dissector_set_key(flow_dissector, key->key_id);
  58                 flow_dissector->offset[key->key_id] = key->offset;
  59         }
  60
  61         /* Ensure that the dissector always includes control and basic key.
  62          * That way we are able to avoid handling lack of these in fast path.
  63          */
  64         BUG_ON(!skb_flow_dissector_uses_key(flow_dissector,
  65                                             FLOW_DISSECTOR_KEY_CONTROL));
  66         BUG_ON(!skb_flow_dissector_uses_key(flow_dissector,
  67                                             FLOW_DISSECTOR_KEY_BASIC));
  68 }
  69 EXPORT_SYMBOL(skb_flow_dissector_init);
  70
  71 /**
  72  * __skb_flow_get_ports - extract the upper layer ports and return them
  73  * @skb: sk_buff to extract the ports from
  74  * @thoff: transport header offset
  75  * @ip_proto: protocol for which to get port offset
  76  * @data: raw buffer pointer to the packet, if NULL use skb->data
  77  * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
  78  *
  79  * The function will try to retrieve the ports at offset thoff + poff where poff
  80  * is the protocol port offset returned from proto_ports_offset
  81  */
  82 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
  83                             void *data, int hlen)
  84 {
  85         int poff = proto_ports_offset(ip_proto);
  86
  87         if (!data) {
  88                 data = skb->data;
  89                 hlen = skb_headlen(skb);
  90         }
  91
  92         if (poff >= 0) {
  93                 __be32 *ports, _ports;
  94
  95                 ports = __skb_header_pointer(skb, thoff + poff,
  96                                              sizeof(_ports), data, hlen, &_ports);
  97                 if (ports)
  98                         return *ports;
  99         }
 100
 101         return 0;
 102 }
 103 EXPORT_SYMBOL(__skb_flow_get_ports);
 104
 105 /**
 106  * __skb_flow_dissect - extract the flow_keys struct and return it
 107  * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
 108  * @flow_dissector: list of keys to dissect
 109  * @target_container: target structure to put dissected values into
 110  * @data: raw buffer pointer to the packet, if NULL use skb->data
 111  * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
 112  * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
 113  * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
 114  *
 115  * The function will try to retrieve individual keys into target specified
 116  * by flow_dissector from either the skbuff or a raw buffer specified by the
 117  * rest parameters.
 118  *
 119  * Caller must take care of zeroing target container memory.
 120  */
 121 bool __skb_flow_dissect(const struct sk_buff *skb,
 122                         struct flow_dissector *flow_dissector,
 123                         void *target_container,
 124                         void *data, __be16 proto, int nhoff, int hlen)
 125 {
 126         struct flow_dissector_key_control *key_control;
 127         struct flow_dissector_key_basic *key_basic;
 128         struct flow_dissector_key_addrs *key_addrs;
 129         struct flow_dissector_key_ports *key_ports;
 130         struct flow_dissector_key_tags *key_tags;
 131         struct flow_dissector_key_keyid *key_keyid;
 132         u8 ip_proto = 0;
 133         bool ret = false;
 134
 135         if (!data) {
 136                 data = skb->data;
 137                 proto = skb->protocol;
 138                 nhoff = skb_network_offset(skb);
 139                 hlen = skb_headlen(skb);
 140         }
 141
 142         /* It is ensured by skb_flow_dissector_init() that control key will
 143          * be always present.
 144          */
 145         key_control = skb_flow_dissector_target(flow_dissector,
 146                                                 FLOW_DISSECTOR_KEY_CONTROL,
 147                                                 target_container);
 148
 149         /* It is ensured by skb_flow_dissector_init() that basic key will
 150          * be always present.
 151          */
 152         key_basic = skb_flow_dissector_target(flow_dissector,
 153                                               FLOW_DISSECTOR_KEY_BASIC,
 154                                               target_container);
 155
 156         if (skb_flow_dissector_uses_key(flow_dissector,
 157                                         FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
 158                 struct ethhdr *eth = eth_hdr(skb);
 159                 struct flow_dissector_key_eth_addrs *key_eth_addrs;
 160
 161                 key_eth_addrs = skb_flow_dissector_target(flow_dissector,
 162                                                           FLOW_DISSECTOR_KEY_ETH_ADDRS,
 163                                                           target_container);
 164                 memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
 165         }
 166
 167 again:
 168         switch (proto) {
 169         case htons(ETH_P_IP): {
 170                 const struct iphdr *iph;
 171                 struct iphdr _iph;
 172 ip:
 173                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 174                 if (!iph || iph->ihl < 5)
 175                         goto out_bad;
 176                 nhoff += iph->ihl * 4;
 177
 178                 ip_proto = iph->protocol;
 179                 if (ip_is_fragment(iph))
 180                         ip_proto = 0;
 181
 182                 if (!skb_flow_dissector_uses_key(flow_dissector,
 183                                                  FLOW_DISSECTOR_KEY_IPV4_ADDRS))
 184                         break;
 185
 186                 key_addrs = skb_flow_dissector_target(flow_dissector,
 187                               FLOW_DISSECTOR_KEY_IPV4_ADDRS, target_container);
 188                 memcpy(&key_addrs->v4addrs, &iph->saddr,
 189                        sizeof(key_addrs->v4addrs));
 190                 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 191                 break;
 192         }
 193         case htons(ETH_P_IPV6): {
 194                 const struct ipv6hdr *iph;
 195                 struct ipv6hdr _iph;
 196                 __be32 flow_label;
 197
 198 ipv6:
 199                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 200                 if (!iph)
 201                         goto out_bad;
 202
 203                 ip_proto = iph->nexthdr;
 204                 nhoff += sizeof(struct ipv6hdr);
 205
 206                 if (skb_flow_dissector_uses_key(flow_dissector,
 207                                                 FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
 208                         struct flow_dissector_key_ipv6_addrs *key_ipv6_addrs;
 209
 210                         key_ipv6_addrs = skb_flow_dissector_target(flow_dissector,
 211                                                                    FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 212                                                                    target_container);
 213
 214                         memcpy(key_ipv6_addrs, &iph->saddr, sizeof(*key_ipv6_addrs));
 215                         key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 216                 }
 217
 218                 flow_label = ip6_flowlabel(iph);
 219                 if (flow_label) {
 220                         if (skb_flow_dissector_uses_key(flow_dissector,
 221                                 FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
 222                                 key_tags = skb_flow_dissector_target(flow_dissector,
 223                                                                      FLOW_DISSECTOR_KEY_FLOW_LABEL,
 224                                                                      target_container);
 225                                 key_tags->flow_label = ntohl(flow_label);
 226                         }
 227                 }
 228
 229                 break;
 230         }
 231         case htons(ETH_P_8021AD):
 232         case htons(ETH_P_8021Q): {
 233                 const struct vlan_hdr *vlan;
 234                 struct vlan_hdr _vlan;
 235
 236                 vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan);
 237                 if (!vlan)
 238                         goto out_bad;
 239
 240                 if (skb_flow_dissector_uses_key(flow_dissector,
 241                                                 FLOW_DISSECTOR_KEY_VLANID)) {
 242                         key_tags = skb_flow_dissector_target(flow_dissector,
 243                                                              FLOW_DISSECTOR_KEY_VLANID,
 244                                                              target_container);
 245
 246                         key_tags->vlan_id = skb_vlan_tag_get_id(skb);
 247                 }
 248
 249                 proto = vlan->h_vlan_encapsulated_proto;
 250                 nhoff += sizeof(*vlan);
 251                 goto again;
 252         }
 253         case htons(ETH_P_PPP_SES): {
 254                 struct {
 255                         struct pppoe_hdr hdr;
 256                         __be16 proto;
 257                 } *hdr, _hdr;
 258                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 259                 if (!hdr)
 260                         goto out_bad;
 261                 proto = hdr->proto;
 262                 nhoff += PPPOE_SES_HLEN;
 263                 switch (proto) {
 264                 case htons(PPP_IP):
 265                         goto ip;
 266                 case htons(PPP_IPV6):
 267                         goto ipv6;
 268                 default:
 269                         goto out_bad;
 270                 }
 271         }
 272         case htons(ETH_P_TIPC): {
 273                 struct {
 274                         __be32 pre[3];
 275                         __be32 srcnode;
 276                 } *hdr, _hdr;
 277                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 278                 if (!hdr)
 279                         goto out_bad;
 280
 281                 if (skb_flow_dissector_uses_key(flow_dissector,
 282                                                 FLOW_DISSECTOR_KEY_TIPC_ADDRS)) {
 283                         key_addrs = skb_flow_dissector_target(flow_dissector,
 284                                                               FLOW_DISSECTOR_KEY_TIPC_ADDRS,
 285                                                               target_container);
 286                         key_addrs->tipcaddrs.srcnode = hdr->srcnode;
 287                         key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS;
 288                 }
 289                 goto out_good;
 290         }
 291
 292         case htons(ETH_P_MPLS_UC):
 293         case htons(ETH_P_MPLS_MC): {
 294                 struct mpls_label *hdr, _hdr[2];
 295 mpls:
 296                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
 297                                            hlen, &_hdr);
 298                 if (!hdr)
 299                         goto out_bad;
 300
 301                 if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
 302                      MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
 303                         if (skb_flow_dissector_uses_key(flow_dissector,
 304                                                         FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) {
 305                                 key_keyid = skb_flow_dissector_target(flow_dissector,
 306                                                                       FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
 307                                                                       target_container);
 308                                 key_keyid->keyid = hdr[1].entry &
 309                                         htonl(MPLS_LS_LABEL_MASK);
 310                         }
 311
 312                         goto out_good;
 313                 }
 314
 315                 goto out_good;
 316         }
 317
 318         case htons(ETH_P_FCOE):
 319                 key_control->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
 320                 /* fall through */
 321         default:
 322                 goto out_bad;
 323         }
 324
 325 ip_proto_again:
 326         switch (ip_proto) {
 327         case IPPROTO_GRE: {
 328                 struct gre_hdr {
 329                         __be16 flags;
 330                         __be16 proto;
 331                 } *hdr, _hdr;
 332
 333                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 334                 if (!hdr)
 335                         goto out_bad;
 336                 /*
 337                  * Only look inside GRE if version zero and no
 338                  * routing
 339                  */
 340                 if (hdr->flags & (GRE_VERSION | GRE_ROUTING))
 341                         break;
 342
 343                 proto = hdr->proto;
 344                 nhoff += 4;
 345                 if (hdr->flags & GRE_CSUM)
 346                         nhoff += 4;
 347                 if (hdr->flags & GRE_KEY) {
 348                         const __be32 *keyid;
 349                         __be32 _keyid;
 350
 351                         keyid = __skb_header_pointer(skb, nhoff, sizeof(_keyid),
 352                                                      data, hlen, &_keyid);
 353
 354                         if (!keyid)
 355                                 goto out_bad;
 356
 357                         if (skb_flow_dissector_uses_key(flow_dissector,
 358                                                         FLOW_DISSECTOR_KEY_GRE_KEYID)) {
 359                                 key_keyid = skb_flow_dissector_target(flow_dissector,
 360                                                                       FLOW_DISSECTOR_KEY_GRE_KEYID,
 361                                                                       target_container);
 362                                 key_keyid->keyid = *keyid;
 363                         }
 364                         nhoff += 4;
 365                 }
 366                 if (hdr->flags & GRE_SEQ)
 367                         nhoff += 4;
 368                 if (proto == htons(ETH_P_TEB)) {
 369                         const struct ethhdr *eth;
 370                         struct ethhdr _eth;
 371
 372                         eth = __skb_header_pointer(skb, nhoff,
 373                                                    sizeof(_eth),
 374                                                    data, hlen, &_eth);
 375                         if (!eth)
 376                                 goto out_bad;
 377                         proto = eth->h_proto;
 378                         nhoff += sizeof(*eth);
 379                 }
 380                 goto again;
 381         }
 382         case NEXTHDR_HOP:
 383         case NEXTHDR_ROUTING:
 384         case NEXTHDR_DEST: {
 385                 u8 _opthdr[2], *opthdr;
 386
 387                 if (proto != htons(ETH_P_IPV6))
 388                         break;
 389
 390                 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
 391                                               data, hlen, &_opthdr);
 392                 if (!opthdr)
 393                         goto out_bad;
 394
 395                 ip_proto = opthdr[0];
 396                 nhoff += (opthdr[1] + 1) << 3;
 397
 398                 goto ip_proto_again;
 399         }
 400         case IPPROTO_IPIP:
 401                 proto = htons(ETH_P_IP);
 402                 goto ip;
 403         case IPPROTO_IPV6:
 404                 proto = htons(ETH_P_IPV6);
 405                 goto ipv6;
 406         case IPPROTO_MPLS:
 407                 proto = htons(ETH_P_MPLS_UC);
 408                 goto mpls;
 409         default:
 410                 break;
 411         }
 412
 413         if (skb_flow_dissector_uses_key(flow_dissector,
 414                                         FLOW_DISSECTOR_KEY_PORTS)) {
 415                 key_ports = skb_flow_dissector_target(flow_dissector,
 416                                                       FLOW_DISSECTOR_KEY_PORTS,
 417                                                       target_container);
 418                 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
 419                                                         data, hlen);
 420         }
 421
 422 out_good:
 423         ret = true;
 424
 425 out_bad:
 426         key_basic->n_proto = proto;
 427         key_basic->ip_proto = ip_proto;
 428         key_control->thoff = (u16)nhoff;
 429
 430         return ret;
 431 }
 432 EXPORT_SYMBOL(__skb_flow_dissect);
 433
 434 static u32 hashrnd __read_mostly;
 435 static __always_inline void __flow_hash_secret_init(void)
 436 {
 437         net_get_random_once(&hashrnd, sizeof(hashrnd));
 438 }
 439
 440 static __always_inline u32 __flow_hash_words(u32 *words, u32 length, u32 keyval)
 441 {
 442         return jhash2(words, length, keyval);
 443 }
 444
 445 static inline void *flow_keys_hash_start(struct flow_keys *flow)
 446 {
 447         BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32));
 448         return (void *)flow + FLOW_KEYS_HASH_OFFSET;
 449 }
 450
 451 static inline size_t flow_keys_hash_length(struct flow_keys *flow)
 452 {
 453         size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs);
 454         BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
 455         BUILD_BUG_ON(offsetof(typeof(*flow), addrs) !=
 456                      sizeof(*flow) - sizeof(flow->addrs));
 457
 458         switch (flow->control.addr_type) {
 459         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 460                 diff -= sizeof(flow->addrs.v4addrs);
 461                 break;
 462         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 463                 diff -= sizeof(flow->addrs.v6addrs);
 464                 break;
 465         case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
 466                 diff -= sizeof(flow->addrs.tipcaddrs);
 467                 break;
 468         }
 469         return (sizeof(*flow) - diff) / sizeof(u32);
 470 }
 471
 472 __be32 flow_get_u32_src(const struct flow_keys *flow)
 473 {
 474         switch (flow->control.addr_type) {
 475         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 476                 return flow->addrs.v4addrs.src;
 477         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 478                 return (__force __be32)ipv6_addr_hash(
 479                         &flow->addrs.v6addrs.src);
 480         case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
 481                 return flow->addrs.tipcaddrs.srcnode;
 482         default:
 483                 return 0;
 484         }
 485 }
 486 EXPORT_SYMBOL(flow_get_u32_src);
 487
 488 __be32 flow_get_u32_dst(const struct flow_keys *flow)
 489 {
 490         switch (flow->control.addr_type) {
 491         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 492                 return flow->addrs.v4addrs.dst;
 493         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 494                 return (__force __be32)ipv6_addr_hash(
 495                         &flow->addrs.v6addrs.dst);
 496         default:
 497                 return 0;
 498         }
 499 }
 500 EXPORT_SYMBOL(flow_get_u32_dst);
 501
 502 static inline void __flow_hash_consistentify(struct flow_keys *keys)
 503 {
 504         int addr_diff, i;
 505
 506         switch (keys->control.addr_type) {
 507         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 508                 addr_diff = (__force u32)keys->addrs.v4addrs.dst -
 509                             (__force u32)keys->addrs.v4addrs.src;
 510                 if ((addr_diff < 0) ||
 511                     (addr_diff == 0 &&
 512                      ((__force u16)keys->ports.dst <
 513                       (__force u16)keys->ports.src))) {
 514                         swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
 515                         swap(keys->ports.src, keys->ports.dst);
 516                 }
 517                 break;
 518         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 519                 addr_diff = memcmp(&keys->addrs.v6addrs.dst,
 520                                    &keys->addrs.v6addrs.src,
 521                                    sizeof(keys->addrs.v6addrs.dst));
 522                 if ((addr_diff < 0) ||
 523                     (addr_diff == 0 &&
 524                      ((__force u16)keys->ports.dst <
 525                       (__force u16)keys->ports.src))) {
 526                         for (i = 0; i < 4; i++)
 527                                 swap(keys->addrs.v6addrs.src.s6_addr32[i],
 528                                      keys->addrs.v6addrs.dst.s6_addr32[i]);
 529                         swap(keys->ports.src, keys->ports.dst);
 530                 }
 531                 break;
 532         }
 533 }
 534
 535 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
 536 {
 537         u32 hash;
 538
 539         __flow_hash_consistentify(keys);
 540
 541         hash = __flow_hash_words((u32 *)flow_keys_hash_start(keys),
 542                                  flow_keys_hash_length(keys), keyval);
 543         if (!hash)
 544                 hash = 1;
 545
 546         return hash;
 547 }
 548
 549 u32 flow_hash_from_keys(struct flow_keys *keys)
 550 {
 551         __flow_hash_secret_init();
 552         return __flow_hash_from_keys(keys, hashrnd);
 553 }
 554 EXPORT_SYMBOL(flow_hash_from_keys);
 555
 556 static inline u32 ___skb_get_hash(const struct sk_buff *skb,
 557                                   struct flow_keys *keys, u32 keyval)
 558 {
 559         if (!skb_flow_dissect_flow_keys(skb, keys))
 560                 return 0;
 561
 562         return __flow_hash_from_keys(keys, keyval);
 563 }
 564
 565 struct _flow_keys_digest_data {
 566         __be16  n_proto;
 567         u8      ip_proto;
 568         u8      padding;
 569         __be32  ports;
 570         __be32  src;
 571         __be32  dst;
 572 };
 573
 574 void make_flow_keys_digest(struct flow_keys_digest *digest,
 575                            const struct flow_keys *flow)
 576 {
 577         struct _flow_keys_digest_data *data =
 578             (struct _flow_keys_digest_data *)digest;
 579
 580         BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));
 581
 582         memset(digest, 0, sizeof(*digest));
 583
 584         data->n_proto = flow->basic.n_proto;
 585         data->ip_proto = flow->basic.ip_proto;
 586         data->ports = flow->ports.ports;
 587         data->src = flow->addrs.v4addrs.src;
 588         data->dst = flow->addrs.v4addrs.dst;
 589 }
 590 EXPORT_SYMBOL(make_flow_keys_digest);
 591
 592 /**
 593  * __skb_get_hash: calculate a flow hash
 594  * @skb: sk_buff to calculate flow hash from
 595  *
 596  * This function calculates a flow hash based on src/dst addresses
 597  * and src/dst port numbers.  Sets hash in skb to non-zero hash value
 598  * on success, zero indicates no valid hash.  Also, sets l4_hash in skb
 599  * if hash is a canonical 4-tuple hash over transport ports.
 600  */
 601 void __skb_get_hash(struct sk_buff *skb)
 602 {
 603         struct flow_keys keys;
 604         u32 hash;
 605
 606         __flow_hash_secret_init();
 607
 608         hash = ___skb_get_hash(skb, &keys, hashrnd);
 609         if (!hash)
 610                 return;
 611
 612         __skb_set_sw_hash(skb, hash,
 613                           flow_keys_have_l4(&keys));
 614 }
 615 EXPORT_SYMBOL(__skb_get_hash);
 616
 617 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
 618 {
 619         struct flow_keys keys;
 620
 621         return ___skb_get_hash(skb, &keys, perturb);
 622 }
 623 EXPORT_SYMBOL(skb_get_hash_perturb);
 624
 625 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, struct flowi6 *fl6)
 626 {
 627         struct flow_keys keys;
 628
 629         memset(&keys, 0, sizeof(keys));
 630
 631         memcpy(&keys.addrs.v6addrs.src, &fl6->saddr,
 632                sizeof(keys.addrs.v6addrs.src));
 633         memcpy(&keys.addrs.v6addrs.dst, &fl6->daddr,
 634                sizeof(keys.addrs.v6addrs.dst));
 635         keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 636         keys.ports.src = fl6->fl6_sport;
 637         keys.ports.dst = fl6->fl6_dport;
 638         keys.keyid.keyid = fl6->fl6_gre_key;
 639         keys.tags.flow_label = (__force u32)fl6->flowlabel;
 640         keys.basic.ip_proto = fl6->flowi6_proto;
 641
 642         __skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
 643                           flow_keys_have_l4(&keys));
 644
 645         return skb->hash;
 646 }
 647 EXPORT_SYMBOL(__skb_get_hash_flowi6);
 648
 649 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, struct flowi4 *fl4)
 650 {
 651         struct flow_keys keys;
 652
 653         memset(&keys, 0, sizeof(keys));
 654
 655         keys.addrs.v4addrs.src = fl4->saddr;
 656         keys.addrs.v4addrs.dst = fl4->daddr;
 657         keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 658         keys.ports.src = fl4->fl4_sport;
 659         keys.ports.dst = fl4->fl4_dport;
 660         keys.keyid.keyid = fl4->fl4_gre_key;
 661         keys.basic.ip_proto = fl4->flowi4_proto;
 662
 663         __skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
 664                           flow_keys_have_l4(&keys));
 665
 666         return skb->hash;
 667 }
 668 EXPORT_SYMBOL(__skb_get_hash_flowi4);
 669
 670 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
 671                    const struct flow_keys *keys, int hlen)
 672 {
 673         u32 poff = keys->control.thoff;
 674
 675         switch (keys->basic.ip_proto) {
 676         case IPPROTO_TCP: {
 677                 /* access doff as u8 to avoid unaligned access */
 678                 const u8 *doff;
 679                 u8 _doff;
 680
 681                 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
 682                                             data, hlen, &_doff);
 683                 if (!doff)
 684                         return poff;
 685
 686                 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
 687                 break;
 688         }
 689         case IPPROTO_UDP:
 690         case IPPROTO_UDPLITE:
 691                 poff += sizeof(struct udphdr);
 692                 break;
 693         /* For the rest, we do not really care about header
 694          * extensions at this point for now.
 695          */
 696         case IPPROTO_ICMP:
 697                 poff += sizeof(struct icmphdr);
 698                 break;
 699         case IPPROTO_ICMPV6:
 700                 poff += sizeof(struct icmp6hdr);
 701                 break;
 702         case IPPROTO_IGMP:
 703                 poff += sizeof(struct igmphdr);
 704                 break;
 705         case IPPROTO_DCCP:
 706                 poff += sizeof(struct dccp_hdr);
 707                 break;
 708         case IPPROTO_SCTP:
 709                 poff += sizeof(struct sctphdr);
 710                 break;
 711         }
 712
 713         return poff;
 714 }
 715
 716 /**
 717  * skb_get_poff - get the offset to the payload
 718  * @skb: sk_buff to get the payload offset from
 719  *
 720  * The function will get the offset to the payload as far as it could
 721  * be dissected.  The main user is currently BPF, so that we can dynamically
 722  * truncate packets without needing to push actual payload to the user
 723  * space and can analyze headers only, instead.
 724  */
 725 u32 skb_get_poff(const struct sk_buff *skb)
 726 {
 727         struct flow_keys keys;
 728
 729         if (!skb_flow_dissect_flow_keys(skb, &keys))
 730                 return 0;
 731
 732         return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
 733 }
 734
 735 static const struct flow_dissector_key flow_keys_dissector_keys[] = {
 736         {
 737                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
 738                 .offset = offsetof(struct flow_keys, control),
 739         },
 740         {
 741                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
 742                 .offset = offsetof(struct flow_keys, basic),
 743         },
 744         {
 745                 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 746                 .offset = offsetof(struct flow_keys, addrs.v4addrs),
 747         },
 748         {
 749                 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 750                 .offset = offsetof(struct flow_keys, addrs.v6addrs),
 751         },
 752         {
 753                 .key_id = FLOW_DISSECTOR_KEY_TIPC_ADDRS,
 754                 .offset = offsetof(struct flow_keys, addrs.tipcaddrs),
 755         },
 756         {
 757                 .key_id = FLOW_DISSECTOR_KEY_PORTS,
 758                 .offset = offsetof(struct flow_keys, ports),
 759         },
 760         {
 761                 .key_id = FLOW_DISSECTOR_KEY_VLANID,
 762                 .offset = offsetof(struct flow_keys, tags),
 763         },
 764         {
 765                 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
 766                 .offset = offsetof(struct flow_keys, tags),
 767         },
 768         {
 769                 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
 770                 .offset = offsetof(struct flow_keys, keyid),
 771         },
 772 };
 773
 774 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
 775         {
 776                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
 777                 .offset = offsetof(struct flow_keys, control),
 778         },
 779         {
 780                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
 781                 .offset = offsetof(struct flow_keys, basic),
 782         },
 783 };
 784
 785 struct flow_dissector flow_keys_dissector __read_mostly;
 786 EXPORT_SYMBOL(flow_keys_dissector);
 787
 788 struct flow_dissector flow_keys_buf_dissector __read_mostly;
 789
 790 static int __init init_default_flow_dissectors(void)
 791 {
 792         skb_flow_dissector_init(&flow_keys_dissector,
 793                                 flow_keys_dissector_keys,
 794                                 ARRAY_SIZE(flow_keys_dissector_keys));
 795         skb_flow_dissector_init(&flow_keys_buf_dissector,
 796                                 flow_keys_buf_dissector_keys,
 797                                 ARRAY_SIZE(flow_keys_buf_dissector_keys));
 798         return 0;
 799 }
 800
 801 late_initcall_sync(init_default_flow_dissectors);