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 dissector_uses_key(const 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 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(dissector_uses_key(flow_dissector,
  55                                           key->key_id));
  56
  57                 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(!dissector_uses_key(flow_dissector,
  65                                    FLOW_DISSECTOR_KEY_CONTROL));
  66         BUG_ON(!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                         unsigned int flags)
 126 {
 127         struct flow_dissector_key_control *key_control;
 128         struct flow_dissector_key_basic *key_basic;
 129         struct flow_dissector_key_addrs *key_addrs;
 130         struct flow_dissector_key_ports *key_ports;
 131         struct flow_dissector_key_tags *key_tags;
 132         struct flow_dissector_key_keyid *key_keyid;
 133         u8 ip_proto = 0;
 134         bool ret = false;
 135
 136         if (!data) {
 137                 data = skb->data;
 138                 proto = skb->protocol;
 139                 nhoff = skb_network_offset(skb);
 140                 hlen = skb_headlen(skb);
 141         }
 142
 143         /* It is ensured by skb_flow_dissector_init() that control key will
 144          * be always present.
 145          */
 146         key_control = skb_flow_dissector_target(flow_dissector,
 147                                                 FLOW_DISSECTOR_KEY_CONTROL,
 148                                                 target_container);
 149
 150         /* It is ensured by skb_flow_dissector_init() that basic key will
 151          * be always present.
 152          */
 153         key_basic = skb_flow_dissector_target(flow_dissector,
 154                                               FLOW_DISSECTOR_KEY_BASIC,
 155                                               target_container);
 156
 157         if (dissector_uses_key(flow_dissector,
 158                                FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
 159                 struct ethhdr *eth = eth_hdr(skb);
 160                 struct flow_dissector_key_eth_addrs *key_eth_addrs;
 161
 162                 key_eth_addrs = skb_flow_dissector_target(flow_dissector,
 163                                                           FLOW_DISSECTOR_KEY_ETH_ADDRS,
 164                                                           target_container);
 165                 memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
 166         }
 167
 168 again:
 169         switch (proto) {
 170         case htons(ETH_P_IP): {
 171                 const struct iphdr *iph;
 172                 struct iphdr _iph;
 173 ip:
 174                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 175                 if (!iph || iph->ihl < 5)
 176                         goto out_bad;
 177                 nhoff += iph->ihl * 4;
 178
 179                 ip_proto = iph->protocol;
 180
 181                 if (!dissector_uses_key(flow_dissector,
 182                                         FLOW_DISSECTOR_KEY_IPV4_ADDRS))
 183                         break;
 184
 185                 key_addrs = skb_flow_dissector_target(flow_dissector,
 186                               FLOW_DISSECTOR_KEY_IPV4_ADDRS, target_container);
 187                 memcpy(&key_addrs->v4addrs, &iph->saddr,
 188                        sizeof(key_addrs->v4addrs));
 189                 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 190
 191                 if (ip_is_fragment(iph)) {
 192                         key_control->flags |= FLOW_DIS_IS_FRAGMENT;
 193
 194                         if (iph->frag_off & htons(IP_OFFSET)) {
 195                                 goto out_good;
 196                         } else {
 197                                 key_control->flags |= FLOW_DIS_FIRST_FRAG;
 198                                 if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
 199                                         goto out_good;
 200                         }
 201                 }
 202
 203                 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
 204                         goto out_good;
 205
 206                 break;
 207         }
 208         case htons(ETH_P_IPV6): {
 209                 const struct ipv6hdr *iph;
 210                 struct ipv6hdr _iph;
 211                 __be32 flow_label;
 212
 213 ipv6:
 214                 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
 215                 if (!iph)
 216                         goto out_bad;
 217
 218                 ip_proto = iph->nexthdr;
 219                 nhoff += sizeof(struct ipv6hdr);
 220
 221                 if (dissector_uses_key(flow_dissector,
 222                                        FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
 223                         struct flow_dissector_key_ipv6_addrs *key_ipv6_addrs;
 224
 225                         key_ipv6_addrs = skb_flow_dissector_target(flow_dissector,
 226                                                                    FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 227                                                                    target_container);
 228
 229                         memcpy(key_ipv6_addrs, &iph->saddr, sizeof(*key_ipv6_addrs));
 230                         key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 231                 }
 232
 233                 flow_label = ip6_flowlabel(iph);
 234                 if (flow_label) {
 235                         if (dissector_uses_key(flow_dissector,
 236                                                FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
 237                                 key_tags = skb_flow_dissector_target(flow_dissector,
 238                                                                      FLOW_DISSECTOR_KEY_FLOW_LABEL,
 239                                                                      target_container);
 240                                 key_tags->flow_label = ntohl(flow_label);
 241                         }
 242                         if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)
 243                                 goto out_good;
 244                 }
 245
 246                 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
 247                         goto out_good;
 248
 249                 break;
 250         }
 251         case htons(ETH_P_8021AD):
 252         case htons(ETH_P_8021Q): {
 253                 const struct vlan_hdr *vlan;
 254                 struct vlan_hdr _vlan;
 255
 256                 vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan);
 257                 if (!vlan)
 258                         goto out_bad;
 259
 260                 if (dissector_uses_key(flow_dissector,
 261                                        FLOW_DISSECTOR_KEY_VLANID)) {
 262                         key_tags = skb_flow_dissector_target(flow_dissector,
 263                                                              FLOW_DISSECTOR_KEY_VLANID,
 264                                                              target_container);
 265
 266                         key_tags->vlan_id = skb_vlan_tag_get_id(skb);
 267                 }
 268
 269                 proto = vlan->h_vlan_encapsulated_proto;
 270                 nhoff += sizeof(*vlan);
 271                 goto again;
 272         }
 273         case htons(ETH_P_PPP_SES): {
 274                 struct {
 275                         struct pppoe_hdr hdr;
 276                         __be16 proto;
 277                 } *hdr, _hdr;
 278                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 279                 if (!hdr)
 280                         goto out_bad;
 281                 proto = hdr->proto;
 282                 nhoff += PPPOE_SES_HLEN;
 283                 switch (proto) {
 284                 case htons(PPP_IP):
 285                         goto ip;
 286                 case htons(PPP_IPV6):
 287                         goto ipv6;
 288                 default:
 289                         goto out_bad;
 290                 }
 291         }
 292         case htons(ETH_P_TIPC): {
 293                 struct {
 294                         __be32 pre[3];
 295                         __be32 srcnode;
 296                 } *hdr, _hdr;
 297                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 298                 if (!hdr)
 299                         goto out_bad;
 300
 301                 if (dissector_uses_key(flow_dissector,
 302                                        FLOW_DISSECTOR_KEY_TIPC_ADDRS)) {
 303                         key_addrs = skb_flow_dissector_target(flow_dissector,
 304                                                               FLOW_DISSECTOR_KEY_TIPC_ADDRS,
 305                                                               target_container);
 306                         key_addrs->tipcaddrs.srcnode = hdr->srcnode;
 307                         key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS;
 308                 }
 309                 goto out_good;
 310         }
 311
 312         case htons(ETH_P_MPLS_UC):
 313         case htons(ETH_P_MPLS_MC): {
 314                 struct mpls_label *hdr, _hdr[2];
 315 mpls:
 316                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
 317                                            hlen, &_hdr);
 318                 if (!hdr)
 319                         goto out_bad;
 320
 321                 if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
 322                      MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
 323                         if (dissector_uses_key(flow_dissector,
 324                                                FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) {
 325                                 key_keyid = skb_flow_dissector_target(flow_dissector,
 326                                                                       FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
 327                                                                       target_container);
 328                                 key_keyid->keyid = hdr[1].entry &
 329                                         htonl(MPLS_LS_LABEL_MASK);
 330                         }
 331
 332                         goto out_good;
 333                 }
 334
 335                 goto out_good;
 336         }
 337
 338         case htons(ETH_P_FCOE):
 339                 key_control->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
 340                 /* fall through */
 341         default:
 342                 goto out_bad;
 343         }
 344
 345 ip_proto_again:
 346         switch (ip_proto) {
 347         case IPPROTO_GRE: {
 348                 struct gre_hdr {
 349                         __be16 flags;
 350                         __be16 proto;
 351                 } *hdr, _hdr;
 352
 353                 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
 354                 if (!hdr)
 355                         goto out_bad;
 356                 /*
 357                  * Only look inside GRE if version zero and no
 358                  * routing
 359                  */
 360                 if (hdr->flags & (GRE_VERSION | GRE_ROUTING))
 361                         break;
 362
 363                 proto = hdr->proto;
 364                 nhoff += 4;
 365                 if (hdr->flags & GRE_CSUM)
 366                         nhoff += 4;
 367                 if (hdr->flags & GRE_KEY) {
 368                         const __be32 *keyid;
 369                         __be32 _keyid;
 370
 371                         keyid = __skb_header_pointer(skb, nhoff, sizeof(_keyid),
 372                                                      data, hlen, &_keyid);
 373
 374                         if (!keyid)
 375                                 goto out_bad;
 376
 377                         if (dissector_uses_key(flow_dissector,
 378                                                FLOW_DISSECTOR_KEY_GRE_KEYID)) {
 379                                 key_keyid = skb_flow_dissector_target(flow_dissector,
 380                                                                       FLOW_DISSECTOR_KEY_GRE_KEYID,
 381                                                                       target_container);
 382                                 key_keyid->keyid = *keyid;
 383                         }
 384                         nhoff += 4;
 385                 }
 386                 if (hdr->flags & GRE_SEQ)
 387                         nhoff += 4;
 388                 if (proto == htons(ETH_P_TEB)) {
 389                         const struct ethhdr *eth;
 390                         struct ethhdr _eth;
 391
 392                         eth = __skb_header_pointer(skb, nhoff,
 393                                                    sizeof(_eth),
 394                                                    data, hlen, &_eth);
 395                         if (!eth)
 396                                 goto out_bad;
 397                         proto = eth->h_proto;
 398                         nhoff += sizeof(*eth);
 399                 }
 400
 401                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 402                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 403                         goto out_good;
 404
 405                 goto again;
 406         }
 407         case NEXTHDR_HOP:
 408         case NEXTHDR_ROUTING:
 409         case NEXTHDR_DEST: {
 410                 u8 _opthdr[2], *opthdr;
 411
 412                 if (proto != htons(ETH_P_IPV6))
 413                         break;
 414
 415                 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
 416                                               data, hlen, &_opthdr);
 417                 if (!opthdr)
 418                         goto out_bad;
 419
 420                 ip_proto = opthdr[0];
 421                 nhoff += (opthdr[1] + 1) << 3;
 422
 423                 goto ip_proto_again;
 424         }
 425         case NEXTHDR_FRAGMENT: {
 426                 struct frag_hdr _fh, *fh;
 427
 428                 if (proto != htons(ETH_P_IPV6))
 429                         break;
 430
 431                 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh),
 432                                           data, hlen, &_fh);
 433
 434                 if (!fh)
 435                         goto out_bad;
 436
 437                 key_control->flags |= FLOW_DIS_IS_FRAGMENT;
 438
 439                 nhoff += sizeof(_fh);
 440
 441                 if (!(fh->frag_off & htons(IP6_OFFSET))) {
 442                         key_control->flags |= FLOW_DIS_FIRST_FRAG;
 443                         if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) {
 444                                 ip_proto = fh->nexthdr;
 445                                 goto ip_proto_again;
 446                         }
 447                 }
 448                 goto out_good;
 449         }
 450         case IPPROTO_IPIP:
 451                 proto = htons(ETH_P_IP);
 452
 453                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 454                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 455                         goto out_good;
 456
 457                 goto ip;
 458         case IPPROTO_IPV6:
 459                 proto = htons(ETH_P_IPV6);
 460
 461                 key_control->flags |= FLOW_DIS_ENCAPSULATION;
 462                 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
 463                         goto out_good;
 464
 465                 goto ipv6;
 466         case IPPROTO_MPLS:
 467                 proto = htons(ETH_P_MPLS_UC);
 468                 goto mpls;
 469         default:
 470                 break;
 471         }
 472
 473         if (dissector_uses_key(flow_dissector,
 474                                FLOW_DISSECTOR_KEY_PORTS)) {
 475                 key_ports = skb_flow_dissector_target(flow_dissector,
 476                                                       FLOW_DISSECTOR_KEY_PORTS,
 477                                                       target_container);
 478                 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
 479                                                         data, hlen);
 480         }
 481
 482 out_good:
 483         ret = true;
 484
 485 out_bad:
 486         key_basic->n_proto = proto;
 487         key_basic->ip_proto = ip_proto;
 488         key_control->thoff = (u16)nhoff;
 489
 490         return ret;
 491 }
 492 EXPORT_SYMBOL(__skb_flow_dissect);
 493
 494 static u32 hashrnd __read_mostly;
 495 static __always_inline void __flow_hash_secret_init(void)
 496 {
 497         net_get_random_once(&hashrnd, sizeof(hashrnd));
 498 }
 499
 500 static __always_inline u32 __flow_hash_words(const u32 *words, u32 length,
 501                                              u32 keyval)
 502 {
 503         return jhash2(words, length, keyval);
 504 }
 505
 506 static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow)
 507 {
 508         const void *p = flow;
 509
 510         BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32));
 511         return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET);
 512 }
 513
 514 static inline size_t flow_keys_hash_length(const struct flow_keys *flow)
 515 {
 516         size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs);
 517         BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32));
 518         BUILD_BUG_ON(offsetof(typeof(*flow), addrs) !=
 519                      sizeof(*flow) - sizeof(flow->addrs));
 520
 521         switch (flow->control.addr_type) {
 522         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 523                 diff -= sizeof(flow->addrs.v4addrs);
 524                 break;
 525         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 526                 diff -= sizeof(flow->addrs.v6addrs);
 527                 break;
 528         case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
 529                 diff -= sizeof(flow->addrs.tipcaddrs);
 530                 break;
 531         }
 532         return (sizeof(*flow) - diff) / sizeof(u32);
 533 }
 534
 535 __be32 flow_get_u32_src(const struct flow_keys *flow)
 536 {
 537         switch (flow->control.addr_type) {
 538         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 539                 return flow->addrs.v4addrs.src;
 540         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 541                 return (__force __be32)ipv6_addr_hash(
 542                         &flow->addrs.v6addrs.src);
 543         case FLOW_DISSECTOR_KEY_TIPC_ADDRS:
 544                 return flow->addrs.tipcaddrs.srcnode;
 545         default:
 546                 return 0;
 547         }
 548 }
 549 EXPORT_SYMBOL(flow_get_u32_src);
 550
 551 __be32 flow_get_u32_dst(const struct flow_keys *flow)
 552 {
 553         switch (flow->control.addr_type) {
 554         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 555                 return flow->addrs.v4addrs.dst;
 556         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 557                 return (__force __be32)ipv6_addr_hash(
 558                         &flow->addrs.v6addrs.dst);
 559         default:
 560                 return 0;
 561         }
 562 }
 563 EXPORT_SYMBOL(flow_get_u32_dst);
 564
 565 static inline void __flow_hash_consistentify(struct flow_keys *keys)
 566 {
 567         int addr_diff, i;
 568
 569         switch (keys->control.addr_type) {
 570         case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
 571                 addr_diff = (__force u32)keys->addrs.v4addrs.dst -
 572                             (__force u32)keys->addrs.v4addrs.src;
 573                 if ((addr_diff < 0) ||
 574                     (addr_diff == 0 &&
 575                      ((__force u16)keys->ports.dst <
 576                       (__force u16)keys->ports.src))) {
 577                         swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
 578                         swap(keys->ports.src, keys->ports.dst);
 579                 }
 580                 break;
 581         case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
 582                 addr_diff = memcmp(&keys->addrs.v6addrs.dst,
 583                                    &keys->addrs.v6addrs.src,
 584                                    sizeof(keys->addrs.v6addrs.dst));
 585                 if ((addr_diff < 0) ||
 586                     (addr_diff == 0 &&
 587                      ((__force u16)keys->ports.dst <
 588                       (__force u16)keys->ports.src))) {
 589                         for (i = 0; i < 4; i++)
 590                                 swap(keys->addrs.v6addrs.src.s6_addr32[i],
 591                                      keys->addrs.v6addrs.dst.s6_addr32[i]);
 592                         swap(keys->ports.src, keys->ports.dst);
 593                 }
 594                 break;
 595         }
 596 }
 597
 598 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval)
 599 {
 600         u32 hash;
 601
 602         __flow_hash_consistentify(keys);
 603
 604         hash = __flow_hash_words(flow_keys_hash_start(keys),
 605                                  flow_keys_hash_length(keys), keyval);
 606         if (!hash)
 607                 hash = 1;
 608
 609         return hash;
 610 }
 611
 612 u32 flow_hash_from_keys(struct flow_keys *keys)
 613 {
 614         __flow_hash_secret_init();
 615         return __flow_hash_from_keys(keys, hashrnd);
 616 }
 617 EXPORT_SYMBOL(flow_hash_from_keys);
 618
 619 static inline u32 ___skb_get_hash(const struct sk_buff *skb,
 620                                   struct flow_keys *keys, u32 keyval)
 621 {
 622         skb_flow_dissect_flow_keys(skb, keys,
 623                                    FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
 624
 625         return __flow_hash_from_keys(keys, keyval);
 626 }
 627
 628 struct _flow_keys_digest_data {
 629         __be16  n_proto;
 630         u8      ip_proto;
 631         u8      padding;
 632         __be32  ports;
 633         __be32  src;
 634         __be32  dst;
 635 };
 636
 637 void make_flow_keys_digest(struct flow_keys_digest *digest,
 638                            const struct flow_keys *flow)
 639 {
 640         struct _flow_keys_digest_data *data =
 641             (struct _flow_keys_digest_data *)digest;
 642
 643         BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));
 644
 645         memset(digest, 0, sizeof(*digest));
 646
 647         data->n_proto = flow->basic.n_proto;
 648         data->ip_proto = flow->basic.ip_proto;
 649         data->ports = flow->ports.ports;
 650         data->src = flow->addrs.v4addrs.src;
 651         data->dst = flow->addrs.v4addrs.dst;
 652 }
 653 EXPORT_SYMBOL(make_flow_keys_digest);
 654
 655 /**
 656  * __skb_get_hash: calculate a flow hash
 657  * @skb: sk_buff to calculate flow hash from
 658  *
 659  * This function calculates a flow hash based on src/dst addresses
 660  * and src/dst port numbers.  Sets hash in skb to non-zero hash value
 661  * on success, zero indicates no valid hash.  Also, sets l4_hash in skb
 662  * if hash is a canonical 4-tuple hash over transport ports.
 663  */
 664 void __skb_get_hash(struct sk_buff *skb)
 665 {
 666         struct flow_keys keys;
 667
 668         __flow_hash_secret_init();
 669
 670         __skb_set_sw_hash(skb, ___skb_get_hash(skb, &keys, hashrnd),
 671                           flow_keys_have_l4(&keys));
 672 }
 673 EXPORT_SYMBOL(__skb_get_hash);
 674
 675 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
 676 {
 677         struct flow_keys keys;
 678
 679         return ___skb_get_hash(skb, &keys, perturb);
 680 }
 681 EXPORT_SYMBOL(skb_get_hash_perturb);
 682
 683 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
 684 {
 685         struct flow_keys keys;
 686
 687         memset(&keys, 0, sizeof(keys));
 688
 689         memcpy(&keys.addrs.v6addrs.src, &fl6->saddr,
 690                sizeof(keys.addrs.v6addrs.src));
 691         memcpy(&keys.addrs.v6addrs.dst, &fl6->daddr,
 692                sizeof(keys.addrs.v6addrs.dst));
 693         keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 694         keys.ports.src = fl6->fl6_sport;
 695         keys.ports.dst = fl6->fl6_dport;
 696         keys.keyid.keyid = fl6->fl6_gre_key;
 697         keys.tags.flow_label = (__force u32)fl6->flowlabel;
 698         keys.basic.ip_proto = fl6->flowi6_proto;
 699
 700         __skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
 701                           flow_keys_have_l4(&keys));
 702
 703         return skb->hash;
 704 }
 705 EXPORT_SYMBOL(__skb_get_hash_flowi6);
 706
 707 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
 708 {
 709         struct flow_keys keys;
 710
 711         memset(&keys, 0, sizeof(keys));
 712
 713         keys.addrs.v4addrs.src = fl4->saddr;
 714         keys.addrs.v4addrs.dst = fl4->daddr;
 715         keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 716         keys.ports.src = fl4->fl4_sport;
 717         keys.ports.dst = fl4->fl4_dport;
 718         keys.keyid.keyid = fl4->fl4_gre_key;
 719         keys.basic.ip_proto = fl4->flowi4_proto;
 720
 721         __skb_set_sw_hash(skb, flow_hash_from_keys(&keys),
 722                           flow_keys_have_l4(&keys));
 723
 724         return skb->hash;
 725 }
 726 EXPORT_SYMBOL(__skb_get_hash_flowi4);
 727
 728 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
 729                    const struct flow_keys *keys, int hlen)
 730 {
 731         u32 poff = keys->control.thoff;
 732
 733         switch (keys->basic.ip_proto) {
 734         case IPPROTO_TCP: {
 735                 /* access doff as u8 to avoid unaligned access */
 736                 const u8 *doff;
 737                 u8 _doff;
 738
 739                 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
 740                                             data, hlen, &_doff);
 741                 if (!doff)
 742                         return poff;
 743
 744                 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
 745                 break;
 746         }
 747         case IPPROTO_UDP:
 748         case IPPROTO_UDPLITE:
 749                 poff += sizeof(struct udphdr);
 750                 break;
 751         /* For the rest, we do not really care about header
 752          * extensions at this point for now.
 753          */
 754         case IPPROTO_ICMP:
 755                 poff += sizeof(struct icmphdr);
 756                 break;
 757         case IPPROTO_ICMPV6:
 758                 poff += sizeof(struct icmp6hdr);
 759                 break;
 760         case IPPROTO_IGMP:
 761                 poff += sizeof(struct igmphdr);
 762                 break;
 763         case IPPROTO_DCCP:
 764                 poff += sizeof(struct dccp_hdr);
 765                 break;
 766         case IPPROTO_SCTP:
 767                 poff += sizeof(struct sctphdr);
 768                 break;
 769         }
 770
 771         return poff;
 772 }
 773
 774 /**
 775  * skb_get_poff - get the offset to the payload
 776  * @skb: sk_buff to get the payload offset from
 777  *
 778  * The function will get the offset to the payload as far as it could
 779  * be dissected.  The main user is currently BPF, so that we can dynamically
 780  * truncate packets without needing to push actual payload to the user
 781  * space and can analyze headers only, instead.
 782  */
 783 u32 skb_get_poff(const struct sk_buff *skb)
 784 {
 785         struct flow_keys keys;
 786
 787         if (!skb_flow_dissect_flow_keys(skb, &keys, 0))
 788                 return 0;
 789
 790         return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
 791 }
 792
 793 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys)
 794 {
 795         memset(keys, 0, sizeof(*keys));
 796
 797         memcpy(&keys->addrs.v6addrs.src, &fl6->saddr,
 798             sizeof(keys->addrs.v6addrs.src));
 799         memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr,
 800             sizeof(keys->addrs.v6addrs.dst));
 801         keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 802         keys->ports.src = fl6->fl6_sport;
 803         keys->ports.dst = fl6->fl6_dport;
 804         keys->keyid.keyid = fl6->fl6_gre_key;
 805         keys->tags.flow_label = (__force u32)fl6->flowlabel;
 806         keys->basic.ip_proto = fl6->flowi6_proto;
 807
 808         return flow_hash_from_keys(keys);
 809 }
 810 EXPORT_SYMBOL(__get_hash_from_flowi6);
 811
 812 __u32 __get_hash_from_flowi4(const struct flowi4 *fl4, struct flow_keys *keys)
 813 {
 814         memset(keys, 0, sizeof(*keys));
 815
 816         keys->addrs.v4addrs.src = fl4->saddr;
 817         keys->addrs.v4addrs.dst = fl4->daddr;
 818         keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 819         keys->ports.src = fl4->fl4_sport;
 820         keys->ports.dst = fl4->fl4_dport;
 821         keys->keyid.keyid = fl4->fl4_gre_key;
 822         keys->basic.ip_proto = fl4->flowi4_proto;
 823
 824         return flow_hash_from_keys(keys);
 825 }
 826 EXPORT_SYMBOL(__get_hash_from_flowi4);
 827
 828 static const struct flow_dissector_key flow_keys_dissector_keys[] = {
 829         {
 830                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
 831                 .offset = offsetof(struct flow_keys, control),
 832         },
 833         {
 834                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
 835                 .offset = offsetof(struct flow_keys, basic),
 836         },
 837         {
 838                 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
 839                 .offset = offsetof(struct flow_keys, addrs.v4addrs),
 840         },
 841         {
 842                 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
 843                 .offset = offsetof(struct flow_keys, addrs.v6addrs),
 844         },
 845         {
 846                 .key_id = FLOW_DISSECTOR_KEY_TIPC_ADDRS,
 847                 .offset = offsetof(struct flow_keys, addrs.tipcaddrs),
 848         },
 849         {
 850                 .key_id = FLOW_DISSECTOR_KEY_PORTS,
 851                 .offset = offsetof(struct flow_keys, ports),
 852         },
 853         {
 854                 .key_id = FLOW_DISSECTOR_KEY_VLANID,
 855                 .offset = offsetof(struct flow_keys, tags),
 856         },
 857         {
 858                 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
 859                 .offset = offsetof(struct flow_keys, tags),
 860         },
 861         {
 862                 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
 863                 .offset = offsetof(struct flow_keys, keyid),
 864         },
 865 };
 866
 867 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {
 868         {
 869                 .key_id = FLOW_DISSECTOR_KEY_CONTROL,
 870                 .offset = offsetof(struct flow_keys, control),
 871         },
 872         {
 873                 .key_id = FLOW_DISSECTOR_KEY_BASIC,
 874                 .offset = offsetof(struct flow_keys, basic),
 875         },
 876 };
 877
 878 struct flow_dissector flow_keys_dissector __read_mostly;
 879 EXPORT_SYMBOL(flow_keys_dissector);
 880
 881 struct flow_dissector flow_keys_buf_dissector __read_mostly;
 882
 883 static int __init init_default_flow_dissectors(void)
 884 {
 885         skb_flow_dissector_init(&flow_keys_dissector,
 886                                 flow_keys_dissector_keys,
 887                                 ARRAY_SIZE(flow_keys_dissector_keys));
 888         skb_flow_dissector_init(&flow_keys_buf_dissector,
 889                                 flow_keys_buf_dissector_keys,
 890                                 ARRAY_SIZE(flow_keys_buf_dissector_keys));
 891         return 0;
 892 }
 893
 894 late_initcall_sync(init_default_flow_dissectors);