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 static __be16 skb_flow_get_be16(const struct sk_buff *skb, int poff,
  71                                 void *data, 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_arp *key_arp;
 142         struct flow_dissector_key_ports *key_ports;
 143         struct flow_dissector_key_icmp *key_icmp;
 144         struct flow_dissector_key_tags *key_tags;
 145         struct flow_dissector_key_vlan *key_vlan;
 146         struct flow_dissector_key_keyid *key_keyid;
 147         bool skip_vlan = false;
 148         u8 ip_proto = 0;
 149         bool ret;
 150
 151         if (!data) {
 152                 data = skb->data;
 153                 proto = skb_vlan_tag_present(skb) ?
 154                          skb->vlan_proto : skb->protocol;
 155                 nhoff = skb_network_offset(skb);
 156                 hlen = skb_headlen(skb);
 157         }
 158
 159         /* It is ensured by skb_flow_dissector_init() that control key will
 160          * be always present.
 161          */
 162         key_control = skb_flow_dissector_target(flow_dissector,
 163                                                 FLOW_DISSECTOR_KEY_CONTROL,
 164                                                 target_container);
 165
 166         /* It is ensured by skb_flow_dissector_init() that basic key will
 167          * be always present.
 168          */
 169         key_basic = skb_flow_dissector_target(flow_dissector,
 170                                               FLOW_DISSECTOR_KEY_BASIC,
 171                                               target_container);
 172
 173         if (dissector_uses_key(flow_dissector,
 174                                FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
 175                 struct ethhdr *eth = eth_hdr(skb);
 176                 struct flow_dissector_key_eth_addrs *key_eth_addrs;
 177
 178                 key_eth_addrs = skb_flow_dissector_target(flow_dissector,
 179                                                           FLOW_DISSECTOR_KEY_ETH_ADDRS,
 180                                                           target_container);
 181                 memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
 182         }
 183
 184 again:
 185         switch (proto) {
 186         case htons(ETH_P_IP): {
 187                 const struct iphdr *iph;
 188                 struct iphdr _iph;
 189 ip:
 190                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 191                 if (!iph || iph->ihl < 5)
 192                         goto out_bad;
 193                 nhoff += iph->ihl * 4;
 194
 195                 ip_proto = iph->protocol;
 196
 197                 if (dissector_uses_key(flow_dissector,
 198                                        FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
 199                         key_addrs = skb_flow_dissector_target(flow_dissector,
 200                                                               FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 201                                                               target_container);
 202
 203                         memcpy(&key_addrs->v4addrs, &iph->saddr,
 204                                sizeof(key_addrs->v4addrs));
 205                         key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 206                 }
 207
 208                 if (ip_is_fragment(iph)) {
 209                         key_control->flags |= FLOW_DIS_IS_FRAGMENT;
 210
 211                         if (iph->frag_off & htons(IP_OFFSET)) {
 212                                 goto out_good;
 213                         } else {
 214                                 key_control->flags |= FLOW_DIS_FIRST_FRAG;
 215                                 if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
 216                                         goto out_good;
 217                         }
 218                 }
 219
 220                 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
 221                         goto out_good;
 222
 223                 break;
 224         }
 225         case htons(ETH_P_IPV6): {
 226                 const struct ipv6hdr *iph;
 227                 struct ipv6hdr _iph;
 228
 229 ipv6:
 230                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 231                 if (!iph)
 232                         goto out_bad;
 233
 234                 ip_proto = iph->nexthdr;
 235                 nhoff += sizeof(struct ipv6hdr);
 236
 237                 if (dissector_uses_key(flow_dissector,
 238                                        FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
 239                         key_addrs = skb_flow_dissector_target(flow_dissector,
 240                                                               FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 241                                                               target_container);
 242
 243                         memcpy(&key_addrs->v6addrs, &iph->saddr,
 244                                sizeof(key_addrs->v6addrs));
 245                         key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 246                 }
 247
 248                 if ((dissector_uses_key(flow_dissector,
 249                                         FLOW_DISSECTOR_KEY_FLOW_LABEL) ||
 250                      (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) &&
 251                     ip6_flowlabel(iph)) {
 252                         __be32 flow_label = ip6_flowlabel(iph);
 253
 254                         if (dissector_uses_key(flow_dissector,
 255                                                FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
 256                                 key_tags = skb_flow_dissector_target(flow_dissector,
 257                                                                      FLOW_DISSECTOR_KEY_FLOW_LABEL,
 258                                                                      target_container);
 259                                 key_tags->flow_label = ntohl(flow_label);
 260                         }
 261                         if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)
 262                                 goto out_good;
 263                 }
 264
 265                 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
 266                         goto out_good;
 267
 268                 break;
 269         }
 270         case htons(ETH_P_8021AD):
 271         case htons(ETH_P_8021Q): {
 272                 const struct vlan_hdr *vlan;
 273                 struct vlan_hdr _vlan;
 274                 bool vlan_tag_present = skb && skb_vlan_tag_present(skb);
 275
 276                 if (vlan_tag_present)
 277                         proto = skb->protocol;
 278
 279                 if (!vlan_tag_present || eth_type_vlan(skb->protocol)) {
 280                         vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),
 281                                                     data, hlen, &_vlan);
 282                         if (!vlan)
 283                                 goto out_bad;
 284                         proto = vlan->h_vlan_encapsulated_proto;
 285                         nhoff += sizeof(*vlan);
 286                         if (skip_vlan)
 287                                 goto again;
 288                 }
 289
 290                 skip_vlan = true;
 291                 if (dissector_uses_key(flow_dissector,
 292                                        FLOW_DISSECTOR_KEY_VLAN)) {
 293                         key_vlan = skb_flow_dissector_target(flow_dissector,
 294                                                              FLOW_DISSECTOR_KEY_VLAN,
 295                                                              target_container);
 296
 297                         if (vlan_tag_present) {
 298                                 key_vlan->vlan_id = skb_vlan_tag_get_id(skb);
 299                                 key_vlan->vlan_priority =
 300                                         (skb_vlan_tag_get_prio(skb) >> VLAN_PRIO_SHIFT);
 301                         } else {
 302                                 key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) &
 303                                         VLAN_VID_MASK;
 304                                 key_vlan->vlan_priority =
 305                                         (ntohs(vlan->h_vlan_TCI) &
 306                                          VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
 307                         }
 308                 }
 309
 310                 goto again;
 311         }
 312         case htons(ETH_P_PPP_SES): {
 313                 struct {
 314                         struct pppoe_hdr hdr;
 315                         __be16 proto;
 316                 } *hdr, _hdr;
 317                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 318                 if (!hdr)
 319                         goto out_bad;
 320                 proto = hdr->proto;
 321                 nhoff += PPPOE_SES_HLEN;
 322                 switch (proto) {
 323                 case htons(PPP_IP):
 324                         goto ip;
 325                 case htons(PPP_IPV6):
 326                         goto ipv6;
 327                 default:
 328                         goto out_bad;
 329                 }
 330         }
 331         case htons(ETH_P_TIPC): {
 332                 struct {
 333                         __be32 pre[3];
 334                         __be32 srcnode;
 335                 } *hdr, _hdr;
 336                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 337                 if (!hdr)
 338                         goto out_bad;
 339
 340                 if (dissector_uses_key(flow_dissector,
 341                                        FLOW_DISSECTOR_KEY_TIPC_ADDRS)) {
 342                         key_addrs = skb_flow_dissector_target(flow_dissector,
 343                                                               FLOW_DISSECTOR_KEY_TIPC_ADDRS,
 344                                                               target_container);
 345                         key_addrs->tipcaddrs.srcnode = hdr->srcnode;
 346                         key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS;
 347                 }
 348                 goto out_good;
 349         }
 350
 351         case htons(ETH_P_MPLS_UC):
 352         case htons(ETH_P_MPLS_MC): {
 353                 struct mpls_label *hdr, _hdr[2];
 354 mpls:
 355                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
 356                                            hlen, &_hdr);
 357                 if (!hdr)
 358                         goto out_bad;
 359
 360                 if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
 361                      MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
 362                         if (dissector_uses_key(flow_dissector,
 363                                                FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) {
 364                                 key_keyid = skb_flow_dissector_target(flow_dissector,
 365                                                                       FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
 366                                                                       target_container);
 367                                 key_keyid->keyid = hdr[1].entry &
 368                                         htonl(MPLS_LS_LABEL_MASK);
 369                         }
 370
 371                         goto out_good;
 372                 }
 373
 374                 goto out_good;
 375         }
 376
 377         case htons(ETH_P_FCOE):
 378                 if ((hlen - nhoff) < FCOE_HEADER_LEN)
 379                         goto out_bad;
 380
 381                 nhoff += FCOE_HEADER_LEN;
 382                 goto out_good;
 383
 384         case htons(ETH_P_ARP):
 385         case htons(ETH_P_RARP): {
 386                 struct {
 387                         unsigned char ar_sha[ETH_ALEN];
 388                         unsigned char ar_sip[4];
 389                         unsigned char ar_tha[ETH_ALEN];
 390                         unsigned char ar_tip[4];
 391                 } *arp_eth, _arp_eth;
 392                 const struct arphdr *arp;
 393                 struct arphdr _arp;
 394
 395                 arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data,
 396                                            hlen, &_arp);
 397                 if (!arp)
 398                         goto out_bad;
 399
 400                 if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
 401                     arp->ar_pro != htons(ETH_P_IP) ||
 402                     arp->ar_hln != ETH_ALEN ||
 403                     arp->ar_pln != 4 ||
 404                     (arp->ar_op != htons(ARPOP_REPLY) &&
 405                      arp->ar_op != htons(ARPOP_REQUEST)))
 406                         goto out_bad;
 407
 408                 arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp),
 409                                                sizeof(_arp_eth), data,
 410                                                hlen,
 411                                                &_arp_eth);
 412                 if (!arp_eth)
 413                         goto out_bad;
 414
 415                 if (dissector_uses_key(flow_dissector,
 416                                        FLOW_DISSECTOR_KEY_ARP)) {
 417
 418                         key_arp = skb_flow_dissector_target(flow_dissector,
 419                                                             FLOW_DISSECTOR_KEY_ARP,
 420                                                             target_container);
 421
 422                         memcpy(&key_arp->sip, arp_eth->ar_sip,
 423                                sizeof(key_arp->sip));
 424                         memcpy(&key_arp->tip, arp_eth->ar_tip,
 425                                sizeof(key_arp->tip));
 426
 427                         /* Only store the lower byte of the opcode;
 428                          * this covers ARPOP_REPLY and ARPOP_REQUEST.
 429                          */
 430                         key_arp->op = ntohs(arp->ar_op) & 0xff;
 431
 432                         ether_addr_copy(key_arp->sha, arp_eth->ar_sha);
 433                         ether_addr_copy(key_arp->tha, arp_eth->ar_tha);
 434                 }
 435
 436                 goto out_good;
 437         }
 438
 439         default:
 440                 goto out_bad;
 441         }
 442
 443 ip_proto_again:
 444         switch (ip_proto) {
 445         case IPPROTO_GRE: {
 446                 struct gre_base_hdr *hdr, _hdr;
 447                 u16 gre_ver;
 448                 int offset = 0;
 449
 450                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 451                 if (!hdr)
 452                         goto out_bad;
 453
 454                 /* Only look inside GRE without routing */
 455                 if (hdr->flags & GRE_ROUTING)
 456                         break;
 457
 458                 /* Only look inside GRE for version 0 and 1 */
 459                 gre_ver = ntohs(hdr->flags & GRE_VERSION);
 460                 if (gre_ver > 1)
 461                         break;
 462
 463                 proto = hdr->protocol;
 464                 if (gre_ver) {
 465                         /* Version1 must be PPTP, and check the flags */
 466                         if (!(proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY)))
 467                                 break;
 468                 }
 469
 470                 offset += sizeof(struct gre_base_hdr);
 471
 472                 if (hdr->flags & GRE_CSUM)
 473                         offset += sizeof(((struct gre_full_hdr *)0)->csum) +
 474                                   sizeof(((struct gre_full_hdr *)0)->reserved1);
 475
 476                 if (hdr->flags & GRE_KEY) {
 477                         const __be32 *keyid;
 478                         __be32 _keyid;
 479
 480                         keyid = __skb_header_pointer(skb, nhoff + offset, sizeof(_keyid),
 481                                                      data, hlen, &_keyid);
 482                         if (!keyid)
 483                                 goto out_bad;
 484
 485                         if (dissector_uses_key(flow_dissector,
 486                                                FLOW_DISSECTOR_KEY_GRE_KEYID)) {
 487                                 key_keyid = skb_flow_dissector_target(flow_dissector,
 488                                                                       FLOW_DISSECTOR_KEY_GRE_KEYID,
 489                                                                       target_container);
 490                                 if (gre_ver == 0)
 491                                         key_keyid->keyid = *keyid;
 492                                 else
 493                                         key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK;
 494                         }
 495                         offset += sizeof(((struct gre_full_hdr *)0)->key);
 496                 }
 497
 498                 if (hdr->flags & GRE_SEQ)
 499                         offset += sizeof(((struct pptp_gre_header *)0)->seq);
 500
 501                 if (gre_ver == 0) {
 502                         if (proto == htons(ETH_P_TEB)) {
 503                                 const struct ethhdr *eth;
 504                                 struct ethhdr _eth;
 505
 506                                 eth = __skb_header_pointer(skb, nhoff + offset,
 507                                                            sizeof(_eth),
 508                                                            data, hlen, &_eth);
 509                                 if (!eth)
 510                                         goto out_bad;
 511                                 proto = eth->h_proto;
 512                                 offset += sizeof(*eth);
 513
 514                                 /* Cap headers that we access via pointers at the
 515                                  * end of the Ethernet header as our maximum alignment
 516                                  * at that point is only 2 bytes.
 517                                  */
 518                                 if (NET_IP_ALIGN)
 519                                         hlen = (nhoff + offset);
 520                         }
 521                 } else { /* version 1, must be PPTP */
 522                         u8 _ppp_hdr[PPP_HDRLEN];
 523                         u8 *ppp_hdr;
 524
 525                         if (hdr->flags & GRE_ACK)
 526                                 offset += sizeof(((struct pptp_gre_header *)0)->ack);
 527
 528                         ppp_hdr = __skb_header_pointer(skb, nhoff + offset,
 529                                                      sizeof(_ppp_hdr),
 530                                                      data, hlen, _ppp_hdr);
 531                         if (!ppp_hdr)
 532                                 goto out_bad;
 533
 534                         switch (PPP_PROTOCOL(ppp_hdr)) {
 535                         case PPP_IP:
 536                                 proto = htons(ETH_P_IP);
 537                                 break;
 538                         case PPP_IPV6:
 539                                 proto = htons(ETH_P_IPV6);
 540                                 break;
 541                         default:
 542                                 /* Could probably catch some more like MPLS */
 543                                 break;
 544                         }
 545
 546                         offset += PPP_HDRLEN;
 547                 }
 548
 549                 nhoff += offset;
 550                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 551                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 552                         goto out_good;
 553
 554                 goto again;
 555         }
 556         case NEXTHDR_HOP:
 557         case NEXTHDR_ROUTING:
 558         case NEXTHDR_DEST: {
 559                 u8 _opthdr[2], *opthdr;
 560
 561                 if (proto != htons(ETH_P_IPV6))
 562                         break;
 563
 564                 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
 565                                               data, hlen, &_opthdr);
 566                 if (!opthdr)
 567                         goto out_bad;
 568
 569                 ip_proto = opthdr[0];
 570                 nhoff += (opthdr[1] + 1) << 3;
 571
 572                 goto ip_proto_again;
 573         }
 574         case NEXTHDR_FRAGMENT: {
 575                 struct frag_hdr _fh, *fh;
 576
 577                 if (proto != htons(ETH_P_IPV6))
 578                         break;
 579
 580                 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh),
 581                                           data, hlen, &_fh);
 582
 583                 if (!fh)
 584                         goto out_bad;
 585
 586                 key_control->flags |= FLOW_DIS_IS_FRAGMENT;
 587
 588                 nhoff += sizeof(_fh);
 589                 ip_proto = fh->nexthdr;
 590
 591                 if (!(fh->frag_off & htons(IP6_OFFSET))) {
 592                         key_control->flags |= FLOW_DIS_FIRST_FRAG;
 593                         if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG)
 594                                 goto ip_proto_again;
 595                 }
 596                 goto out_good;
 597         }
 598         case IPPROTO_IPIP:
 599                 proto = htons(ETH_P_IP);
 600
 601                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 602                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 603                         goto out_good;
 604
 605                 goto ip;
 606         case IPPROTO_IPV6:
 607                 proto = htons(ETH_P_IPV6);
 608
 609                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 610                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 611                         goto out_good;
 612
 613                 goto ipv6;
 614         case IPPROTO_MPLS:
 615                 proto = htons(ETH_P_MPLS_UC);
 616                 goto mpls;
 617         default:
 618                 break;
 619         }
 620
 621         if (dissector_uses_key(flow_dissector,
 622                                FLOW_DISSECTOR_KEY_PORTS)) {
 623                 key_ports = skb_flow_dissector_target(flow_dissector,
 624                                                       FLOW_DISSECTOR_KEY_PORTS,
 625                                                       target_container);
 626                 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
 627                                                         data, hlen);
 628         }
 629
 630         if (dissector_uses_key(flow_dissector,
 631                                FLOW_DISSECTOR_KEY_ICMP)) {
 632                 key_icmp = skb_flow_dissector_target(flow_dissector,
 633                                                      FLOW_DISSECTOR_KEY_ICMP,
 634                                                      target_container);
 635                 key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen);
 636         }
 637
 638 out_good:
 639         ret = true;
 640
 641         key_control->thoff = (u16)nhoff;
 642 out:
 643         key_basic->n_proto = proto;
 644         key_basic->ip_proto = ip_proto;
 645
 646         return ret;
 647
 648 out_bad:
 649         ret = false;
 650         key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
 651         goto out;
 652 }
 653 EXPORT_SYMBOL(__skb_flow_dissect);
 654
 655 static u32 hashrnd __read_mostly;
 656 static __always_inline void __flow_hash_secret_init(void)
 657 {
 658         net_get_random_once(&hashrnd, sizeof(hashrnd));
 659 }
 660
 661 static __always_inline u32 __flow_hash_words(const u32 *words, u32 length,
 662                                              u32 keyval)
 663 {
 664         return jhash2(words, length, keyval);
 665 }
 666
 667 static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow)
 668 {
 669         const void *p = flow;
 670
 671         BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32));
 672         return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET);
 673 }
 674
 675 static inline size_t flow_keys_hash_length(const struct flow_keys *flow)
 676 {
 677         size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs);
 678         BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
 679         BUILD_BUG_ON(offsetof(typeof(*flow), addrs) !=
 680                      sizeof(*flow) - sizeof(flow->addrs));
 681
 682         switch (flow->control.addr_type) {
 683         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 684                 diff -= sizeof(flow->addrs.v4addrs);
 685                 break;
 686         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 687                 diff -= sizeof(flow->addrs.v6addrs);
 688                 break;
 689         case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
 690                 diff -= sizeof(flow->addrs.tipcaddrs);
 691                 break;
 692         }
 693         return (sizeof(*flow) - diff) / sizeof(u32);
 694 }
 695
 696 __be32 flow_get_u32_src(const struct flow_keys *flow)
 697 {
 698         switch (flow->control.addr_type) {
 699         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 700                 return flow->addrs.v4addrs.src;
 701         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 702                 return (__force __be32)ipv6_addr_hash(
 703                         &flow->addrs.v6addrs.src);
 704         case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
 705                 return flow->addrs.tipcaddrs.srcnode;
 706         default:
 707                 return 0;
 708         }
 709 }
 710 EXPORT_SYMBOL(flow_get_u32_src);
 711
 712 __be32 flow_get_u32_dst(const struct flow_keys *flow)
 713 {
 714         switch (flow->control.addr_type) {
 715         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 716                 return flow->addrs.v4addrs.dst;
 717         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 718                 return (__force __be32)ipv6_addr_hash(
 719                         &flow->addrs.v6addrs.dst);
 720         default:
 721                 return 0;
 722         }
 723 }
 724 EXPORT_SYMBOL(flow_get_u32_dst);
 725
 726 static inline void __flow_hash_consistentify(struct flow_keys *keys)
 727 {
 728         int addr_diff, i;
 729
 730         switch (keys->control.addr_type) {
 731         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 732                 addr_diff = (__force u32)keys->addrs.v4addrs.dst -
 733                             (__force u32)keys->addrs.v4addrs.src;
 734                 if ((addr_diff < 0) ||
 735                     (addr_diff == 0 &&
 736                      ((__force u16)keys->ports.dst <
 737                       (__force u16)keys->ports.src))) {
 738                         swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
 739                         swap(keys->ports.src, keys->ports.dst);
 740                 }
 741                 break;
 742         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 743                 addr_diff = memcmp(&keys->addrs.v6addrs.dst,
 744                                    &keys->addrs.v6addrs.src,
 745                                    sizeof(keys->addrs.v6addrs.dst));
 746                 if ((addr_diff < 0) ||
 747                     (addr_diff == 0 &&
 748                      ((__force u16)keys->ports.dst <
 749                       (__force u16)keys->ports.src))) {
 750                         for (i = 0; i < 4; i++)
 751                                 swap(keys->addrs.v6addrs.src.s6_addr32[i],
 752                                      keys->addrs.v6addrs.dst.s6_addr32[i]);
 753                         swap(keys->ports.src, keys->ports.dst);
 754                 }
 755                 break;
 756         }
 757 }
 758
 759 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
 760 {
 761         u32 hash;
 762
 763         __flow_hash_consistentify(keys);
 764
 765         hash = __flow_hash_words(flow_keys_hash_start(keys),
 766                                  flow_keys_hash_length(keys), keyval);
 767         if (!hash)
 768                 hash = 1;
 769
 770         return hash;
 771 }
 772
 773 u32 flow_hash_from_keys(struct flow_keys *keys)
 774 {
 775         __flow_hash_secret_init();
 776         return __flow_hash_from_keys(keys, hashrnd);
 777 }
 778 EXPORT_SYMBOL(flow_hash_from_keys);
 779
 780 static inline u32 ___skb_get_hash(const struct sk_buff *skb,
 781                                   struct flow_keys *keys, u32 keyval)
 782 {
 783         skb_flow_dissect_flow_keys(skb, keys,
 784                                    FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
 785
 786         return __flow_hash_from_keys(keys, keyval);
 787 }
 788
 789 struct _flow_keys_digest_data {
 790         __be16  n_proto;
 791         u8      ip_proto;
 792         u8      padding;
 793         __be32  ports;
 794         __be32  src;
 795         __be32  dst;
 796 };
 797
 798 void make_flow_keys_digest(struct flow_keys_digest *digest,
 799                            const struct flow_keys *flow)
 800 {
 801         struct _flow_keys_digest_data *data =
 802             (struct _flow_keys_digest_data *)digest;
 803
 804         BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));
 805
 806         memset(digest, 0, sizeof(*digest));
 807
 808         data->n_proto = flow->basic.n_proto;
 809         data->ip_proto = flow->basic.ip_proto;
 810         data->ports = flow->ports.ports;
 811         data->src = flow->addrs.v4addrs.src;
 812         data->dst = flow->addrs.v4addrs.dst;
 813 }
 814 EXPORT_SYMBOL(make_flow_keys_digest);
 815
 816 static struct flow_dissector flow_keys_dissector_symmetric __read_mostly;
 817
 818 u32 __skb_get_hash_symmetric(const struct sk_buff *skb)
 819 {
 820         struct flow_keys keys;
 821
 822         __flow_hash_secret_init();
 823
 824         memset(&keys, 0, sizeof(keys));
 825         __skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys,
 826                            NULL, 0, 0, 0,
 827                            FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
 828
 829         return __flow_hash_from_keys(&keys, hashrnd);
 830 }
 831 EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric);
 832
 833 /**
 834  * __skb_get_hash: calculate a flow hash
 835  * @skb: sk_buff to calculate flow hash from
 836  *
 837  * This function calculates a flow hash based on src/dst addresses
 838  * and src/dst port numbers.  Sets hash in skb to non-zero hash value
 839  * on success, zero indicates no valid hash.  Also, sets l4_hash in skb
 840  * if hash is a canonical 4-tuple hash over transport ports.
 841  */
 842 void __skb_get_hash(struct sk_buff *skb)
 843 {
 844         struct flow_keys keys;
 845         u32 hash;
 846
 847         __flow_hash_secret_init();
 848
 849         hash = ___skb_get_hash(skb, &keys, hashrnd);
 850
 851         __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
 852 }
 853 EXPORT_SYMBOL(__skb_get_hash);
 854
 855 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
 856 {
 857         struct flow_keys keys;
 858
 859         return ___skb_get_hash(skb, &keys, perturb);
 860 }
 861 EXPORT_SYMBOL(skb_get_hash_perturb);
 862
 863 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
 864 {
 865         struct flow_keys keys;
 866
 867         memset(&keys, 0, sizeof(keys));
 868
 869         memcpy(&keys.addrs.v6addrs.src, &fl6->saddr,
 870                sizeof(keys.addrs.v6addrs.src));
 871         memcpy(&keys.addrs.v6addrs.dst, &fl6->daddr,
 872                sizeof(keys.addrs.v6addrs.dst));
 873         keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 874         keys.ports.src = fl6->fl6_sport;
 875         keys.ports.dst = fl6->fl6_dport;
 876         keys.keyid.keyid = fl6->fl6_gre_key;
 877         keys.tags.flow_label = (__force u32)fl6->flowlabel;
 878         keys.basic.ip_proto = fl6->flowi6_proto;
 879
 880         __skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
 881                           flow_keys_have_l4(&keys));
 882
 883         return skb->hash;
 884 }
 885 EXPORT_SYMBOL(__skb_get_hash_flowi6);
 886
 887 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
 888 {
 889         struct flow_keys keys;
 890
 891         memset(&keys, 0, sizeof(keys));
 892
 893         keys.addrs.v4addrs.src = fl4->saddr;
 894         keys.addrs.v4addrs.dst = fl4->daddr;
 895         keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 896         keys.ports.src = fl4->fl4_sport;
 897         keys.ports.dst = fl4->fl4_dport;
 898         keys.keyid.keyid = fl4->fl4_gre_key;
 899         keys.basic.ip_proto = fl4->flowi4_proto;
 900
 901         __skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
 902                           flow_keys_have_l4(&keys));
 903
 904         return skb->hash;
 905 }
 906 EXPORT_SYMBOL(__skb_get_hash_flowi4);
 907
 908 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
 909                    const struct flow_keys *keys, int hlen)
 910 {
 911         u32 poff = keys->control.thoff;
 912
 913         /* skip L4 headers for fragments after the first */
 914         if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) &&
 915             !(keys->control.flags & FLOW_DIS_FIRST_FRAG))
 916                 return poff;
 917
 918         switch (keys->basic.ip_proto) {
 919         case IPPROTO_TCP: {
 920                 /* access doff as u8 to avoid unaligned access */
 921                 const u8 *doff;
 922                 u8 _doff;
 923
 924                 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
 925                                             data, hlen, &_doff);
 926                 if (!doff)
 927                         return poff;
 928
 929                 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
 930                 break;
 931         }
 932         case IPPROTO_UDP:
 933         case IPPROTO_UDPLITE:
 934                 poff += sizeof(struct udphdr);
 935                 break;
 936         /* For the rest, we do not really care about header
 937          * extensions at this point for now.
 938          */
 939         case IPPROTO_ICMP:
 940                 poff += sizeof(struct icmphdr);
 941                 break;
 942         case IPPROTO_ICMPV6:
 943                 poff += sizeof(struct icmp6hdr);
 944                 break;
 945         case IPPROTO_IGMP:
 946                 poff += sizeof(struct igmphdr);
 947                 break;
 948         case IPPROTO_DCCP:
 949                 poff += sizeof(struct dccp_hdr);
 950                 break;
 951         case IPPROTO_SCTP:
 952                 poff += sizeof(struct sctphdr);
 953                 break;
 954         }
 955
 956         return poff;
 957 }
 958
 959 /**
 960  * skb_get_poff - get the offset to the payload
 961  * @skb: sk_buff to get the payload offset from
 962  *
 963  * The function will get the offset to the payload as far as it could
 964  * be dissected.  The main user is currently BPF, so that we can dynamically
 965  * truncate packets without needing to push actual payload to the user
 966  * space and can analyze headers only, instead.
 967  */
 968 u32 skb_get_poff(const struct sk_buff *skb)
 969 {
 970         struct flow_keys keys;
 971
 972         if (!skb_flow_dissect_flow_keys(skb, &keys, 0))
 973                 return 0;
 974
 975         return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
 976 }
 977
 978 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys)
 979 {
 980         memset(keys, 0, sizeof(*keys));
 981
 982         memcpy(&keys->addrs.v6addrs.src, &fl6->saddr,
 983             sizeof(keys->addrs.v6addrs.src));
 984         memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr,
 985             sizeof(keys->addrs.v6addrs.dst));
 986         keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 987         keys->ports.src = fl6->fl6_sport;
 988         keys->ports.dst = fl6->fl6_dport;
 989         keys->keyid.keyid = fl6->fl6_gre_key;
 990         keys->tags.flow_label = (__force u32)fl6->flowlabel;
 991         keys->basic.ip_proto = fl6->flowi6_proto;
 992
 993         return flow_hash_from_keys(keys);
 994 }
 995 EXPORT_SYMBOL(__get_hash_from_flowi6);
 996
 997 __u32 __get_hash_from_flowi4(const struct flowi4 *fl4, struct flow_keys *keys)
 998 {
 999         memset(keys, 0, sizeof(*keys));
1000
1001         keys->addrs.v4addrs.src = fl4->saddr;
1002         keys->addrs.v4addrs.dst = fl4->daddr;
1003         keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1004         keys->ports.src = fl4->fl4_sport;
1005         keys->ports.dst = fl4->fl4_dport;
1006         keys->keyid.keyid = fl4->fl4_gre_key;
1007         keys->basic.ip_proto = fl4->flowi4_proto;
1008
1009         return flow_hash_from_keys(keys);
1010 }
1011 EXPORT_SYMBOL(__get_hash_from_flowi4);
1012
1013 static const struct flow_dissector_key flow_keys_dissector_keys[] = {
1014         {
1015                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
1016                 .offset = offsetof(struct flow_keys, control),
1017         },
1018         {
1019                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
1020                 .offset = offsetof(struct flow_keys, basic),
1021         },
1022         {
1023                 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
1024                 .offset = offsetof(struct flow_keys, addrs.v4addrs),
1025         },
1026         {
1027                 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
1028                 .offset = offsetof(struct flow_keys, addrs.v6addrs),
1029         },
1030         {
1031                 .key_id = FLOW_DISSECTOR_KEY_TIPC_ADDRS,
1032                 .offset = offsetof(struct flow_keys, addrs.tipcaddrs),
1033         },
1034         {
1035                 .key_id = FLOW_DISSECTOR_KEY_PORTS,
1036                 .offset = offsetof(struct flow_keys, ports),
1037         },
1038         {
1039                 .key_id = FLOW_DISSECTOR_KEY_VLAN,
1040                 .offset = offsetof(struct flow_keys, vlan),
1041         },
1042         {
1043                 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
1044                 .offset = offsetof(struct flow_keys, tags),
1045         },
1046         {
1047                 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
1048                 .offset = offsetof(struct flow_keys, keyid),
1049         },
1050 };
1051
1052 static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = {
1053         {
1054                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
1055                 .offset = offsetof(struct flow_keys, control),
1056         },
1057         {
1058                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
1059                 .offset = offsetof(struct flow_keys, basic),
1060         },
1061         {
1062                 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
1063                 .offset = offsetof(struct flow_keys, addrs.v4addrs),
1064         },
1065         {
1066                 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
1067                 .offset = offsetof(struct flow_keys, addrs.v6addrs),
1068         },
1069         {
1070                 .key_id = FLOW_DISSECTOR_KEY_PORTS,
1071                 .offset = offsetof(struct flow_keys, ports),
1072         },
1073 };
1074
1075 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
1076         {
1077                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
1078                 .offset = offsetof(struct flow_keys, control),
1079         },
1080         {
1081                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
1082                 .offset = offsetof(struct flow_keys, basic),
1083         },
1084 };
1085
1086 struct flow_dissector flow_keys_dissector __read_mostly;
1087 EXPORT_SYMBOL(flow_keys_dissector);
1088
1089 struct flow_dissector flow_keys_buf_dissector __read_mostly;
1090
1091 static int __init init_default_flow_dissectors(void)
1092 {
1093         skb_flow_dissector_init(&flow_keys_dissector,
1094                                 flow_keys_dissector_keys,
1095                                 ARRAY_SIZE(flow_keys_dissector_keys));
1096         skb_flow_dissector_init(&flow_keys_dissector_symmetric,
1097                                 flow_keys_dissector_symmetric_keys,
1098                                 ARRAY_SIZE(flow_keys_dissector_symmetric_keys));
1099         skb_flow_dissector_init(&flow_keys_buf_dissector,
1100                                 flow_keys_buf_dissector_keys,
1101                                 ARRAY_SIZE(flow_keys_buf_dissector_keys));
1102         return 0;
1103 }
1104
1105 core_initcall(init_default_flow_dissectors);