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