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 <net/gre.h>
  10 #include <net/pptp.h>
  11 #include <linux/igmp.h>
  12 #include <linux/icmp.h>
  13 #include <linux/sctp.h>
  14 #include <linux/dccp.h>
  15 #include <linux/if_tunnel.h>
  16 #include <linux/if_pppox.h>
  17 #include <linux/ppp_defs.h>
  18 #include <linux/stddef.h>
  19 #include <linux/if_ether.h>
  20 #include <linux/mpls.h>
  21 #include <net/flow_dissector.h>
  22 #include <scsi/fc/fc_fcoe.h>
  23
  24 static void dissector_set_key(struct flow_dissector *flow_dissector,
  25                               enum flow_dissector_key_id key_id)
  26 {
  27         flow_dissector->used_keys |= (1 << key_id);
  28 }
  29
  30 void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
  31                              const struct flow_dissector_key *key,
  32                              unsigned int key_count)
  33 {
  34         unsigned int i;
  35
  36         memset(flow_dissector, 0, sizeof(*flow_dissector));
  37
  38         for (i = 0; i < key_count; i++, key++) {
  39                 /* User should make sure that every key target offset is withing
  40                  * boundaries of unsigned short.
  41                  */
  42                 BUG_ON(key->offset > USHRT_MAX);
  43                 BUG_ON(dissector_uses_key(flow_dissector,
  44                                           key->key_id));
  45
  46                 dissector_set_key(flow_dissector, key->key_id);
  47                 flow_dissector->offset[key->key_id] = key->offset;
  48         }
  49
  50         /* Ensure that the dissector always includes control and basic key.
  51          * That way we are able to avoid handling lack of these in fast path.
  52          */
  53         BUG_ON(!dissector_uses_key(flow_dissector,
  54                                    FLOW_DISSECTOR_KEY_CONTROL));
  55         BUG_ON(!dissector_uses_key(flow_dissector,
  56                                    FLOW_DISSECTOR_KEY_BASIC));
  57 }
  58 EXPORT_SYMBOL(skb_flow_dissector_init);
  59
  60 /**
  61  * skb_flow_get_be16 - extract be16 entity
  62  * @skb: sk_buff to extract from
  63  * @poff: offset to extract at
  64  * @data: raw buffer pointer to the packet
  65  * @hlen: packet header length
  66  *
  67  * The function will try to retrieve a be32 entity at
  68  * offset poff
  69  */
  70 __be16 skb_flow_get_be16(const struct sk_buff *skb, int poff, void *data,
  71                          int hlen)
  72 {
  73         __be16 *u, _u;
  74
  75         u = __skb_header_pointer(skb, poff, sizeof(_u), data, hlen, &_u);
  76         if (u)
  77                 return *u;
  78
  79         return 0;
  80 }
  81
  82 /**
  83  * __skb_flow_get_ports - extract the upper layer ports and return them
  84  * @skb: sk_buff to extract the ports from
  85  * @thoff: transport header offset
  86  * @ip_proto: protocol for which to get port offset
  87  * @data: raw buffer pointer to the packet, if NULL use skb->data
  88  * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
  89  *
  90  * The function will try to retrieve the ports at offset thoff + poff where poff
  91  * is the protocol port offset returned from proto_ports_offset
  92  */
  93 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
  94                             void *data, int hlen)
  95 {
  96         int poff = proto_ports_offset(ip_proto);
  97
  98         if (!data) {
  99                 data = skb->data;
 100                 hlen = skb_headlen(skb);
 101         }
 102
 103         if (poff >= 0) {
 104                 __be32 *ports, _ports;
 105
 106                 ports = __skb_header_pointer(skb, thoff + poff,
 107                                              sizeof(_ports), data, hlen, &_ports);
 108                 if (ports)
 109                         return *ports;
 110         }
 111
 112         return 0;
 113 }
 114 EXPORT_SYMBOL(__skb_flow_get_ports);
 115
 116 /**
 117  * __skb_flow_dissect - extract the flow_keys struct and return it
 118  * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
 119  * @flow_dissector: list of keys to dissect
 120  * @target_container: target structure to put dissected values into
 121  * @data: raw buffer pointer to the packet, if NULL use skb->data
 122  * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
 123  * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
 124  * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
 125  *
 126  * The function will try to retrieve individual keys into target specified
 127  * by flow_dissector from either the skbuff or a raw buffer specified by the
 128  * rest parameters.
 129  *
 130  * Caller must take care of zeroing target container memory.
 131  */
 132 bool __skb_flow_dissect(const struct sk_buff *skb,
 133                         struct flow_dissector *flow_dissector,
 134                         void *target_container,
 135                         void *data, __be16 proto, int nhoff, int hlen,
 136                         unsigned int flags)
 137 {
 138         struct flow_dissector_key_control *key_control;
 139         struct flow_dissector_key_basic *key_basic;
 140         struct flow_dissector_key_addrs *key_addrs;
 141         struct flow_dissector_key_ports *key_ports;
 142         struct flow_dissector_key_icmp *key_icmp;
 143         struct flow_dissector_key_tags *key_tags;
 144         struct flow_dissector_key_vlan *key_vlan;
 145         struct flow_dissector_key_keyid *key_keyid;
 146         bool skip_vlan = false;
 147         u8 ip_proto = 0;
 148         bool ret;
 149
 150         if (!data) {
 151                 data = skb->data;
 152                 proto = skb_vlan_tag_present(skb) ?
 153                          skb->vlan_proto : skb->protocol;
 154                 nhoff = skb_network_offset(skb);
 155                 hlen = skb_headlen(skb);
 156         }
 157
 158         /* It is ensured by skb_flow_dissector_init() that control key will
 159          * be always present.
 160          */
 161         key_control = skb_flow_dissector_target(flow_dissector,
 162                                                 FLOW_DISSECTOR_KEY_CONTROL,
 163                                                 target_container);
 164
 165         /* It is ensured by skb_flow_dissector_init() that basic key will
 166          * be always present.
 167          */
 168         key_basic = skb_flow_dissector_target(flow_dissector,
 169                                               FLOW_DISSECTOR_KEY_BASIC,
 170                                               target_container);
 171
 172         if (dissector_uses_key(flow_dissector,
 173                                FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
 174                 struct ethhdr *eth = eth_hdr(skb);
 175                 struct flow_dissector_key_eth_addrs *key_eth_addrs;
 176
 177                 key_eth_addrs = skb_flow_dissector_target(flow_dissector,
 178                                                           FLOW_DISSECTOR_KEY_ETH_ADDRS,
 179                                                           target_container);
 180                 memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
 181         }
 182
 183 again:
 184         switch (proto) {
 185         case htons(ETH_P_IP): {
 186                 const struct iphdr *iph;
 187                 struct iphdr _iph;
 188 ip:
 189                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 190                 if (!iph || iph->ihl < 5)
 191                         goto out_bad;
 192                 nhoff += iph->ihl * 4;
 193
 194                 ip_proto = iph->protocol;
 195
 196                 if (dissector_uses_key(flow_dissector,
 197                                        FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
 198                         key_addrs = skb_flow_dissector_target(flow_dissector,
 199                                                               FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 200                                                               target_container);
 201
 202                         memcpy(&key_addrs->v4addrs, &iph->saddr,
 203                                sizeof(key_addrs->v4addrs));
 204                         key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 205                 }
 206
 207                 if (ip_is_fragment(iph)) {
 208                         key_control->flags |= FLOW_DIS_IS_FRAGMENT;
 209
 210                         if (iph->frag_off & htons(IP_OFFSET)) {
 211                                 goto out_good;
 212                         } else {
 213                                 key_control->flags |= FLOW_DIS_FIRST_FRAG;
 214                                 if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
 215                                         goto out_good;
 216                         }
 217                 }
 218
 219                 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
 220                         goto out_good;
 221
 222                 break;
 223         }
 224         case htons(ETH_P_IPV6): {
 225                 const struct ipv6hdr *iph;
 226                 struct ipv6hdr _iph;
 227
 228 ipv6:
 229                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 230                 if (!iph)
 231                         goto out_bad;
 232
 233                 ip_proto = iph->nexthdr;
 234                 nhoff += sizeof(struct ipv6hdr);
 235
 236                 if (dissector_uses_key(flow_dissector,
 237                                        FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
 238                         key_addrs = skb_flow_dissector_target(flow_dissector,
 239                                                               FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 240                                                               target_container);
 241
 242                         memcpy(&key_addrs->v6addrs, &iph->saddr,
 243                                sizeof(key_addrs->v6addrs));
 244                         key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 245                 }
 246
 247                 if ((dissector_uses_key(flow_dissector,
 248                                         FLOW_DISSECTOR_KEY_FLOW_LABEL) ||
 249                      (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) &&
 250                     ip6_flowlabel(iph)) {
 251                         __be32 flow_label = ip6_flowlabel(iph);
 252
 253                         if (dissector_uses_key(flow_dissector,
 254                                                FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
 255                                 key_tags = skb_flow_dissector_target(flow_dissector,
 256                                                                      FLOW_DISSECTOR_KEY_FLOW_LABEL,
 257                                                                      target_container);
 258                                 key_tags->flow_label = ntohl(flow_label);
 259                         }
 260                         if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)
 261                                 goto out_good;
 262                 }
 263
 264                 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
 265                         goto out_good;
 266
 267                 break;
 268         }
 269         case htons(ETH_P_8021AD):
 270         case htons(ETH_P_8021Q): {
 271                 const struct vlan_hdr *vlan;
 272                 struct vlan_hdr _vlan;
 273                 bool vlan_tag_present = skb && skb_vlan_tag_present(skb);
 274
 275                 if (vlan_tag_present)
 276                         proto = skb->protocol;
 277
 278                 if (!vlan_tag_present || eth_type_vlan(skb->protocol)) {
 279                         vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),
 280                                                     data, hlen, &_vlan);
 281                         if (!vlan)
 282                                 goto out_bad;
 283                         proto = vlan->h_vlan_encapsulated_proto;
 284                         nhoff += sizeof(*vlan);
 285                         if (skip_vlan)
 286                                 goto again;
 287                 }
 288
 289                 skip_vlan = true;
 290                 if (dissector_uses_key(flow_dissector,
 291                                        FLOW_DISSECTOR_KEY_VLAN)) {
 292                         key_vlan = skb_flow_dissector_target(flow_dissector,
 293                                                              FLOW_DISSECTOR_KEY_VLAN,
 294                                                              target_container);
 295
 296                         if (vlan_tag_present) {
 297                                 key_vlan->vlan_id = skb_vlan_tag_get_id(skb);
 298                                 key_vlan->vlan_priority =
 299                                         (skb_vlan_tag_get_prio(skb) >> VLAN_PRIO_SHIFT);
 300                         } else {
 301                                 key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) &
 302                                         VLAN_VID_MASK;
 303                                 key_vlan->vlan_priority =
 304                                         (ntohs(vlan->h_vlan_TCI) &
 305                                          VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
 306                         }
 307                 }
 308
 309                 goto again;
 310         }
 311         case htons(ETH_P_PPP_SES): {
 312                 struct {
 313                         struct pppoe_hdr hdr;
 314                         __be16 proto;
 315                 } *hdr, _hdr;
 316                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 317                 if (!hdr)
 318                         goto out_bad;
 319                 proto = hdr->proto;
 320                 nhoff += PPPOE_SES_HLEN;
 321                 switch (proto) {
 322                 case htons(PPP_IP):
 323                         goto ip;
 324                 case htons(PPP_IPV6):
 325                         goto ipv6;
 326                 default:
 327                         goto out_bad;
 328                 }
 329         }
 330         case htons(ETH_P_TIPC): {
 331                 struct {
 332                         __be32 pre[3];
 333                         __be32 srcnode;
 334                 } *hdr, _hdr;
 335                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 336                 if (!hdr)
 337                         goto out_bad;
 338
 339                 if (dissector_uses_key(flow_dissector,
 340                                        FLOW_DISSECTOR_KEY_TIPC_ADDRS)) {
 341                         key_addrs = skb_flow_dissector_target(flow_dissector,
 342                                                               FLOW_DISSECTOR_KEY_TIPC_ADDRS,
 343                                                               target_container);
 344                         key_addrs->tipcaddrs.srcnode = hdr->srcnode;
 345                         key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS;
 346                 }
 347                 goto out_good;
 348         }
 349
 350         case htons(ETH_P_MPLS_UC):
 351         case htons(ETH_P_MPLS_MC): {
 352                 struct mpls_label *hdr, _hdr[2];
 353 mpls:
 354                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
 355                                            hlen, &_hdr);
 356                 if (!hdr)
 357                         goto out_bad;
 358
 359                 if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
 360                      MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
 361                         if (dissector_uses_key(flow_dissector,
 362                                                FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) {
 363                                 key_keyid = skb_flow_dissector_target(flow_dissector,
 364                                                                       FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
 365                                                                       target_container);
 366                                 key_keyid->keyid = hdr[1].entry &
 367                                         htonl(MPLS_LS_LABEL_MASK);
 368                         }
 369
 370                         goto out_good;
 371                 }
 372
 373                 goto out_good;
 374         }
 375
 376         case htons(ETH_P_FCOE):
 377                 if ((hlen - nhoff) < FCOE_HEADER_LEN)
 378                         goto out_bad;
 379
 380                 nhoff += FCOE_HEADER_LEN;
 381                 goto out_good;
 382         default:
 383                 goto out_bad;
 384         }
 385
 386 ip_proto_again:
 387         switch (ip_proto) {
 388         case IPPROTO_GRE: {
 389                 struct gre_base_hdr *hdr, _hdr;
 390                 u16 gre_ver;
 391                 int offset = 0;
 392
 393                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 394                 if (!hdr)
 395                         goto out_bad;
 396
 397                 /* Only look inside GRE without routing */
 398                 if (hdr->flags & GRE_ROUTING)
 399                         break;
 400
 401                 /* Only look inside GRE for version 0 and 1 */
 402                 gre_ver = ntohs(hdr->flags & GRE_VERSION);
 403                 if (gre_ver > 1)
 404                         break;
 405
 406                 proto = hdr->protocol;
 407                 if (gre_ver) {
 408                         /* Version1 must be PPTP, and check the flags */
 409                         if (!(proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY)))
 410                                 break;
 411                 }
 412
 413                 offset += sizeof(struct gre_base_hdr);
 414
 415                 if (hdr->flags & GRE_CSUM)
 416                         offset += sizeof(((struct gre_full_hdr *)0)->csum) +
 417                                   sizeof(((struct gre_full_hdr *)0)->reserved1);
 418
 419                 if (hdr->flags & GRE_KEY) {
 420                         const __be32 *keyid;
 421                         __be32 _keyid;
 422
 423                         keyid = __skb_header_pointer(skb, nhoff + offset, sizeof(_keyid),
 424                                                      data, hlen, &_keyid);
 425                         if (!keyid)
 426                                 goto out_bad;
 427
 428                         if (dissector_uses_key(flow_dissector,
 429                                                FLOW_DISSECTOR_KEY_GRE_KEYID)) {
 430                                 key_keyid = skb_flow_dissector_target(flow_dissector,
 431                                                                       FLOW_DISSECTOR_KEY_GRE_KEYID,
 432                                                                       target_container);
 433                                 if (gre_ver == 0)
 434                                         key_keyid->keyid = *keyid;
 435                                 else
 436                                         key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK;
 437                         }
 438                         offset += sizeof(((struct gre_full_hdr *)0)->key);
 439                 }
 440
 441                 if (hdr->flags & GRE_SEQ)
 442                         offset += sizeof(((struct pptp_gre_header *)0)->seq);
 443
 444                 if (gre_ver == 0) {
 445                         if (proto == htons(ETH_P_TEB)) {
 446                                 const struct ethhdr *eth;
 447                                 struct ethhdr _eth;
 448
 449                                 eth = __skb_header_pointer(skb, nhoff + offset,
 450                                                            sizeof(_eth),
 451                                                            data, hlen, &_eth);
 452                                 if (!eth)
 453                                         goto out_bad;
 454                                 proto = eth->h_proto;
 455                                 offset += sizeof(*eth);
 456
 457                                 /* Cap headers that we access via pointers at the
 458                                  * end of the Ethernet header as our maximum alignment
 459                                  * at that point is only 2 bytes.
 460                                  */
 461                                 if (NET_IP_ALIGN)
 462                                         hlen = (nhoff + offset);
 463                         }
 464                 } else { /* version 1, must be PPTP */
 465                         u8 _ppp_hdr[PPP_HDRLEN];
 466                         u8 *ppp_hdr;
 467
 468                         if (hdr->flags & GRE_ACK)
 469                                 offset += sizeof(((struct pptp_gre_header *)0)->ack);
 470
 471                         ppp_hdr = skb_header_pointer(skb, nhoff + offset,
 472                                                      sizeof(_ppp_hdr), _ppp_hdr);
 473                         if (!ppp_hdr)
 474                                 goto out_bad;
 475
 476                         switch (PPP_PROTOCOL(ppp_hdr)) {
 477                         case PPP_IP:
 478                                 proto = htons(ETH_P_IP);
 479                                 break;
 480                         case PPP_IPV6:
 481                                 proto = htons(ETH_P_IPV6);
 482                                 break;
 483                         default:
 484                                 /* Could probably catch some more like MPLS */
 485                                 break;
 486                         }
 487
 488                         offset += PPP_HDRLEN;
 489                 }
 490
 491                 nhoff += offset;
 492                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 493                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 494                         goto out_good;
 495
 496                 goto again;
 497         }
 498         case NEXTHDR_HOP:
 499         case NEXTHDR_ROUTING:
 500         case NEXTHDR_DEST: {
 501                 u8 _opthdr[2], *opthdr;
 502
 503                 if (proto != htons(ETH_P_IPV6))
 504                         break;
 505
 506                 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
 507                                               data, hlen, &_opthdr);
 508                 if (!opthdr)
 509                         goto out_bad;
 510
 511                 ip_proto = opthdr[0];
 512                 nhoff += (opthdr[1] + 1) << 3;
 513
 514                 goto ip_proto_again;
 515         }
 516         case NEXTHDR_FRAGMENT: {
 517                 struct frag_hdr _fh, *fh;
 518
 519                 if (proto != htons(ETH_P_IPV6))
 520                         break;
 521
 522                 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh),
 523                                           data, hlen, &_fh);
 524
 525                 if (!fh)
 526                         goto out_bad;
 527
 528                 key_control->flags |= FLOW_DIS_IS_FRAGMENT;
 529
 530                 nhoff += sizeof(_fh);
 531                 ip_proto = fh->nexthdr;
 532
 533                 if (!(fh->frag_off & htons(IP6_OFFSET))) {
 534                         key_control->flags |= FLOW_DIS_FIRST_FRAG;
 535                         if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG)
 536                                 goto ip_proto_again;
 537                 }
 538                 goto out_good;
 539         }
 540         case IPPROTO_IPIP:
 541                 proto = htons(ETH_P_IP);
 542
 543                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 544                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 545                         goto out_good;
 546
 547                 goto ip;
 548         case IPPROTO_IPV6:
 549                 proto = htons(ETH_P_IPV6);
 550
 551                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 552                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 553                         goto out_good;
 554
 555                 goto ipv6;
 556         case IPPROTO_MPLS:
 557                 proto = htons(ETH_P_MPLS_UC);
 558                 goto mpls;
 559         default:
 560                 break;
 561         }
 562
 563         if (dissector_uses_key(flow_dissector,
 564                                FLOW_DISSECTOR_KEY_PORTS)) {
 565                 key_ports = skb_flow_dissector_target(flow_dissector,
 566                                                       FLOW_DISSECTOR_KEY_PORTS,
 567                                                       target_container);
 568                 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
 569                                                         data, hlen);
 570         }
 571
 572         if (dissector_uses_key(flow_dissector,
 573                                FLOW_DISSECTOR_KEY_ICMP)) {
 574                 key_icmp = skb_flow_dissector_target(flow_dissector,
 575                                                      FLOW_DISSECTOR_KEY_ICMP,
 576                                                      target_container);
 577                 key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen);
 578         }
 579
 580 out_good:
 581         ret = true;
 582
 583         key_control->thoff = (u16)nhoff;
 584 out:
 585         key_basic->n_proto = proto;
 586         key_basic->ip_proto = ip_proto;
 587
 588         return ret;
 589
 590 out_bad:
 591         ret = false;
 592         key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
 593         goto out;
 594 }
 595 EXPORT_SYMBOL(__skb_flow_dissect);
 596
 597 static u32 hashrnd __read_mostly;
 598 static __always_inline void __flow_hash_secret_init(void)
 599 {
 600         net_get_random_once(&hashrnd, sizeof(hashrnd));
 601 }
 602
 603 static __always_inline u32 __flow_hash_words(const u32 *words, u32 length,
 604                                              u32 keyval)
 605 {
 606         return jhash2(words, length, keyval);
 607 }
 608
 609 static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow)
 610 {
 611         const void *p = flow;
 612
 613         BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32));
 614         return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET);
 615 }
 616
 617 static inline size_t flow_keys_hash_length(const struct flow_keys *flow)
 618 {
 619         size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs);
 620         BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
 621         BUILD_BUG_ON(offsetof(typeof(*flow), addrs) !=
 622                      sizeof(*flow) - sizeof(flow->addrs));
 623
 624         switch (flow->control.addr_type) {
 625         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 626                 diff -= sizeof(flow->addrs.v4addrs);
 627                 break;
 628         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 629                 diff -= sizeof(flow->addrs.v6addrs);
 630                 break;
 631         case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
 632                 diff -= sizeof(flow->addrs.tipcaddrs);
 633                 break;
 634         }
 635         return (sizeof(*flow) - diff) / sizeof(u32);
 636 }
 637
 638 __be32 flow_get_u32_src(const struct flow_keys *flow)
 639 {
 640         switch (flow->control.addr_type) {
 641         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 642                 return flow->addrs.v4addrs.src;
 643         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 644                 return (__force __be32)ipv6_addr_hash(
 645                         &flow->addrs.v6addrs.src);
 646         case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
 647                 return flow->addrs.tipcaddrs.srcnode;
 648         default:
 649                 return 0;
 650         }
 651 }
 652 EXPORT_SYMBOL(flow_get_u32_src);
 653
 654 __be32 flow_get_u32_dst(const struct flow_keys *flow)
 655 {
 656         switch (flow->control.addr_type) {
 657         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 658                 return flow->addrs.v4addrs.dst;
 659         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 660                 return (__force __be32)ipv6_addr_hash(
 661                         &flow->addrs.v6addrs.dst);
 662         default:
 663                 return 0;
 664         }
 665 }
 666 EXPORT_SYMBOL(flow_get_u32_dst);
 667
 668 static inline void __flow_hash_consistentify(struct flow_keys *keys)
 669 {
 670         int addr_diff, i;
 671
 672         switch (keys->control.addr_type) {
 673         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 674                 addr_diff = (__force u32)keys->addrs.v4addrs.dst -
 675                             (__force u32)keys->addrs.v4addrs.src;
 676                 if ((addr_diff < 0) ||
 677                     (addr_diff == 0 &&
 678                      ((__force u16)keys->ports.dst <
 679                       (__force u16)keys->ports.src))) {
 680                         swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
 681                         swap(keys->ports.src, keys->ports.dst);
 682                 }
 683                 break;
 684         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 685                 addr_diff = memcmp(&keys->addrs.v6addrs.dst,
 686                                    &keys->addrs.v6addrs.src,
 687                                    sizeof(keys->addrs.v6addrs.dst));
 688                 if ((addr_diff < 0) ||
 689                     (addr_diff == 0 &&
 690                      ((__force u16)keys->ports.dst <
 691                       (__force u16)keys->ports.src))) {
 692                         for (i = 0; i < 4; i++)
 693                                 swap(keys->addrs.v6addrs.src.s6_addr32[i],
 694                                      keys->addrs.v6addrs.dst.s6_addr32[i]);
 695                         swap(keys->ports.src, keys->ports.dst);
 696                 }
 697                 break;
 698         }
 699 }
 700
 701 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
 702 {
 703         u32 hash;
 704
 705         __flow_hash_consistentify(keys);
 706
 707         hash = __flow_hash_words(flow_keys_hash_start(keys),
 708                                  flow_keys_hash_length(keys), keyval);
 709         if (!hash)
 710                 hash = 1;
 711
 712         return hash;
 713 }
 714
 715 u32 flow_hash_from_keys(struct flow_keys *keys)
 716 {
 717         __flow_hash_secret_init();
 718         return __flow_hash_from_keys(keys, hashrnd);
 719 }
 720 EXPORT_SYMBOL(flow_hash_from_keys);
 721
 722 static inline u32 ___skb_get_hash(const struct sk_buff *skb,
 723                                   struct flow_keys *keys, u32 keyval)
 724 {
 725         skb_flow_dissect_flow_keys(skb, keys,
 726                                    FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
 727
 728         return __flow_hash_from_keys(keys, keyval);
 729 }
 730
 731 struct _flow_keys_digest_data {
 732         __be16  n_proto;
 733         u8      ip_proto;
 734         u8      padding;
 735         __be32  ports;
 736         __be32  src;
 737         __be32  dst;
 738 };
 739
 740 void make_flow_keys_digest(struct flow_keys_digest *digest,
 741                            const struct flow_keys *flow)
 742 {
 743         struct _flow_keys_digest_data *data =
 744             (struct _flow_keys_digest_data *)digest;
 745
 746         BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));
 747
 748         memset(digest, 0, sizeof(*digest));
 749
 750         data->n_proto = flow->basic.n_proto;
 751         data->ip_proto = flow->basic.ip_proto;
 752         data->ports = flow->ports.ports;
 753         data->src = flow->addrs.v4addrs.src;
 754         data->dst = flow->addrs.v4addrs.dst;
 755 }
 756 EXPORT_SYMBOL(make_flow_keys_digest);
 757
 758 static struct flow_dissector flow_keys_dissector_symmetric __read_mostly;
 759
 760 u32 __skb_get_hash_symmetric(const struct sk_buff *skb)
 761 {
 762         struct flow_keys keys;
 763
 764         __flow_hash_secret_init();
 765
 766         memset(&keys, 0, sizeof(keys));
 767         __skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys,
 768                            NULL, 0, 0, 0,
 769                            FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
 770
 771         return __flow_hash_from_keys(&keys, hashrnd);
 772 }
 773 EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric);
 774
 775 /**
 776  * __skb_get_hash: calculate a flow hash
 777  * @skb: sk_buff to calculate flow hash from
 778  *
 779  * This function calculates a flow hash based on src/dst addresses
 780  * and src/dst port numbers.  Sets hash in skb to non-zero hash value
 781  * on success, zero indicates no valid hash.  Also, sets l4_hash in skb
 782  * if hash is a canonical 4-tuple hash over transport ports.
 783  */
 784 void __skb_get_hash(struct sk_buff *skb)
 785 {
 786         struct flow_keys keys;
 787         u32 hash;
 788
 789         __flow_hash_secret_init();
 790
 791         hash = ___skb_get_hash(skb, &keys, hashrnd);
 792
 793         __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
 794 }
 795 EXPORT_SYMBOL(__skb_get_hash);
 796
 797 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
 798 {
 799         struct flow_keys keys;
 800
 801         return ___skb_get_hash(skb, &keys, perturb);
 802 }
 803 EXPORT_SYMBOL(skb_get_hash_perturb);
 804
 805 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
 806 {
 807         struct flow_keys keys;
 808
 809         memset(&keys, 0, sizeof(keys));
 810
 811         memcpy(&keys.addrs.v6addrs.src, &fl6->saddr,
 812                sizeof(keys.addrs.v6addrs.src));
 813         memcpy(&keys.addrs.v6addrs.dst, &fl6->daddr,
 814                sizeof(keys.addrs.v6addrs.dst));
 815         keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 816         keys.ports.src = fl6->fl6_sport;
 817         keys.ports.dst = fl6->fl6_dport;
 818         keys.keyid.keyid = fl6->fl6_gre_key;
 819         keys.tags.flow_label = (__force u32)fl6->flowlabel;
 820         keys.basic.ip_proto = fl6->flowi6_proto;
 821
 822         __skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
 823                           flow_keys_have_l4(&keys));
 824
 825         return skb->hash;
 826 }
 827 EXPORT_SYMBOL(__skb_get_hash_flowi6);
 828
 829 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
 830 {
 831         struct flow_keys keys;
 832
 833         memset(&keys, 0, sizeof(keys));
 834
 835         keys.addrs.v4addrs.src = fl4->saddr;
 836         keys.addrs.v4addrs.dst = fl4->daddr;
 837         keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 838         keys.ports.src = fl4->fl4_sport;
 839         keys.ports.dst = fl4->fl4_dport;
 840         keys.keyid.keyid = fl4->fl4_gre_key;
 841         keys.basic.ip_proto = fl4->flowi4_proto;
 842
 843         __skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
 844                           flow_keys_have_l4(&keys));
 845
 846         return skb->hash;
 847 }
 848 EXPORT_SYMBOL(__skb_get_hash_flowi4);
 849
 850 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
 851                    const struct flow_keys *keys, int hlen)
 852 {
 853         u32 poff = keys->control.thoff;
 854
 855         /* skip L4 headers for fragments after the first */
 856         if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) &&
 857             !(keys->control.flags & FLOW_DIS_FIRST_FRAG))
 858                 return poff;
 859
 860         switch (keys->basic.ip_proto) {
 861         case IPPROTO_TCP: {
 862                 /* access doff as u8 to avoid unaligned access */
 863                 const u8 *doff;
 864                 u8 _doff;
 865
 866                 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
 867                                             data, hlen, &_doff);
 868                 if (!doff)
 869                         return poff;
 870
 871                 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
 872                 break;
 873         }
 874         case IPPROTO_UDP:
 875         case IPPROTO_UDPLITE:
 876                 poff += sizeof(struct udphdr);
 877                 break;
 878         /* For the rest, we do not really care about header
 879          * extensions at this point for now.
 880          */
 881         case IPPROTO_ICMP:
 882                 poff += sizeof(struct icmphdr);
 883                 break;
 884         case IPPROTO_ICMPV6:
 885                 poff += sizeof(struct icmp6hdr);
 886                 break;
 887         case IPPROTO_IGMP:
 888                 poff += sizeof(struct igmphdr);
 889                 break;
 890         case IPPROTO_DCCP:
 891                 poff += sizeof(struct dccp_hdr);
 892                 break;
 893         case IPPROTO_SCTP:
 894                 poff += sizeof(struct sctphdr);
 895                 break;
 896         }
 897
 898         return poff;
 899 }
 900
 901 /**
 902  * skb_get_poff - get the offset to the payload
 903  * @skb: sk_buff to get the payload offset from
 904  *
 905  * The function will get the offset to the payload as far as it could
 906  * be dissected.  The main user is currently BPF, so that we can dynamically
 907  * truncate packets without needing to push actual payload to the user
 908  * space and can analyze headers only, instead.
 909  */
 910 u32 skb_get_poff(const struct sk_buff *skb)
 911 {
 912         struct flow_keys keys;
 913
 914         if (!skb_flow_dissect_flow_keys(skb, &keys, 0))
 915                 return 0;
 916
 917         return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
 918 }
 919
 920 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys)
 921 {
 922         memset(keys, 0, sizeof(*keys));
 923
 924         memcpy(&keys->addrs.v6addrs.src, &fl6->saddr,
 925             sizeof(keys->addrs.v6addrs.src));
 926         memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr,
 927             sizeof(keys->addrs.v6addrs.dst));
 928         keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 929         keys->ports.src = fl6->fl6_sport;
 930         keys->ports.dst = fl6->fl6_dport;
 931         keys->keyid.keyid = fl6->fl6_gre_key;
 932         keys->tags.flow_label = (__force u32)fl6->flowlabel;
 933         keys->basic.ip_proto = fl6->flowi6_proto;
 934
 935         return flow_hash_from_keys(keys);
 936 }
 937 EXPORT_SYMBOL(__get_hash_from_flowi6);
 938
 939 __u32 __get_hash_from_flowi4(const struct flowi4 *fl4, struct flow_keys *keys)
 940 {
 941         memset(keys, 0, sizeof(*keys));
 942
 943         keys->addrs.v4addrs.src = fl4->saddr;
 944         keys->addrs.v4addrs.dst = fl4->daddr;
 945         keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 946         keys->ports.src = fl4->fl4_sport;
 947         keys->ports.dst = fl4->fl4_dport;
 948         keys->keyid.keyid = fl4->fl4_gre_key;
 949         keys->basic.ip_proto = fl4->flowi4_proto;
 950
 951         return flow_hash_from_keys(keys);
 952 }
 953 EXPORT_SYMBOL(__get_hash_from_flowi4);
 954
 955 static const struct flow_dissector_key flow_keys_dissector_keys[] = {
 956         {
 957                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
 958                 .offset = offsetof(struct flow_keys, control),
 959         },
 960         {
 961                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
 962                 .offset = offsetof(struct flow_keys, basic),
 963         },
 964         {
 965                 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 966                 .offset = offsetof(struct flow_keys, addrs.v4addrs),
 967         },
 968         {
 969                 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 970                 .offset = offsetof(struct flow_keys, addrs.v6addrs),
 971         },
 972         {
 973                 .key_id = FLOW_DISSECTOR_KEY_TIPC_ADDRS,
 974                 .offset = offsetof(struct flow_keys, addrs.tipcaddrs),
 975         },
 976         {
 977                 .key_id = FLOW_DISSECTOR_KEY_PORTS,
 978                 .offset = offsetof(struct flow_keys, ports),
 979         },
 980         {
 981                 .key_id = FLOW_DISSECTOR_KEY_VLAN,
 982                 .offset = offsetof(struct flow_keys, vlan),
 983         },
 984         {
 985                 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
 986                 .offset = offsetof(struct flow_keys, tags),
 987         },
 988         {
 989                 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
 990                 .offset = offsetof(struct flow_keys, keyid),
 991         },
 992 };
 993
 994 static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = {
 995         {
 996                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
 997                 .offset = offsetof(struct flow_keys, control),
 998         },
 999         {
1000                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
1001                 .offset = offsetof(struct flow_keys, basic),
1002         },
1003         {
1004                 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
1005                 .offset = offsetof(struct flow_keys, addrs.v4addrs),
1006         },
1007         {
1008                 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
1009                 .offset = offsetof(struct flow_keys, addrs.v6addrs),
1010         },
1011         {
1012                 .key_id = FLOW_DISSECTOR_KEY_PORTS,
1013                 .offset = offsetof(struct flow_keys, ports),
1014         },
1015 };
1016
1017 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
1018         {
1019                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
1020                 .offset = offsetof(struct flow_keys, control),
1021         },
1022         {
1023                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
1024                 .offset = offsetof(struct flow_keys, basic),
1025         },
1026 };
1027
1028 struct flow_dissector flow_keys_dissector __read_mostly;
1029 EXPORT_SYMBOL(flow_keys_dissector);
1030
1031 struct flow_dissector flow_keys_buf_dissector __read_mostly;
1032
1033 static int __init init_default_flow_dissectors(void)
1034 {
1035         skb_flow_dissector_init(&flow_keys_dissector,
1036                                 flow_keys_dissector_keys,
1037                                 ARRAY_SIZE(flow_keys_dissector_keys));
1038         skb_flow_dissector_init(&flow_keys_dissector_symmetric,
1039                                 flow_keys_dissector_symmetric_keys,
1040                                 ARRAY_SIZE(flow_keys_dissector_symmetric_keys));
1041         skb_flow_dissector_init(&flow_keys_buf_dissector,
1042                                 flow_keys_buf_dissector_keys,
1043                                 ARRAY_SIZE(flow_keys_buf_dissector_keys));
1044         return 0;
1045 }
1046
1047 core_initcall(init_default_flow_dissectors);