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, ð->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 key_addrs = skb_flow_dissector_target(flow_dissector, 184 FLOW_DISSECTOR_KEY_IPV4_ADDRS, 185 target_container); 186 187 memcpy(&key_addrs->v4addrs, &iph->saddr, 188 sizeof(key_addrs->v4addrs)); 189 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 190 } 191 192 if (ip_is_fragment(iph)) { 193 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 194 195 if (iph->frag_off & htons(IP_OFFSET)) { 196 goto out_good; 197 } else { 198 key_control->flags |= FLOW_DIS_FIRST_FRAG; 199 if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) 200 goto out_good; 201 } 202 } 203 204 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) 205 goto out_good; 206 207 break; 208 } 209 case htons(ETH_P_IPV6): { 210 const struct ipv6hdr *iph; 211 struct ipv6hdr _iph; 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 key_addrs = skb_flow_dissector_target(flow_dissector, 224 FLOW_DISSECTOR_KEY_IPV6_ADDRS, 225 target_container); 226 227 memcpy(&key_addrs->v6addrs, &iph->saddr, 228 sizeof(key_addrs->v6addrs)); 229 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 230 } 231 232 if ((dissector_uses_key(flow_dissector, 233 FLOW_DISSECTOR_KEY_FLOW_LABEL) || 234 (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) && 235 ip6_flowlabel(iph)) { 236 __be32 flow_label = ip6_flowlabel(iph); 237 238 if (dissector_uses_key(flow_dissector, 239 FLOW_DISSECTOR_KEY_FLOW_LABEL)) { 240 key_tags = skb_flow_dissector_target(flow_dissector, 241 FLOW_DISSECTOR_KEY_FLOW_LABEL, 242 target_container); 243 key_tags->flow_label = ntohl(flow_label); 244 } 245 if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) 246 goto out_good; 247 } 248 249 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) 250 goto out_good; 251 252 break; 253 } 254 case htons(ETH_P_8021AD): 255 case htons(ETH_P_8021Q): { 256 const struct vlan_hdr *vlan; 257 struct vlan_hdr _vlan; 258 259 vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan); 260 if (!vlan) 261 goto out_bad; 262 263 if (dissector_uses_key(flow_dissector, 264 FLOW_DISSECTOR_KEY_VLANID)) { 265 key_tags = skb_flow_dissector_target(flow_dissector, 266 FLOW_DISSECTOR_KEY_VLANID, 267 target_container); 268 269 key_tags->vlan_id = skb_vlan_tag_get_id(skb); 270 } 271 272 proto = vlan->h_vlan_encapsulated_proto; 273 nhoff += sizeof(*vlan); 274 goto again; 275 } 276 case htons(ETH_P_PPP_SES): { 277 struct { 278 struct pppoe_hdr hdr; 279 __be16 proto; 280 } *hdr, _hdr; 281 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 282 if (!hdr) 283 goto out_bad; 284 proto = hdr->proto; 285 nhoff += PPPOE_SES_HLEN; 286 switch (proto) { 287 case htons(PPP_IP): 288 goto ip; 289 case htons(PPP_IPV6): 290 goto ipv6; 291 default: 292 goto out_bad; 293 } 294 } 295 case htons(ETH_P_TIPC): { 296 struct { 297 __be32 pre[3]; 298 __be32 srcnode; 299 } *hdr, _hdr; 300 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 301 if (!hdr) 302 goto out_bad; 303 304 if (dissector_uses_key(flow_dissector, 305 FLOW_DISSECTOR_KEY_TIPC_ADDRS)) { 306 key_addrs = skb_flow_dissector_target(flow_dissector, 307 FLOW_DISSECTOR_KEY_TIPC_ADDRS, 308 target_container); 309 key_addrs->tipcaddrs.srcnode = hdr->srcnode; 310 key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS; 311 } 312 goto out_good; 313 } 314 315 case htons(ETH_P_MPLS_UC): 316 case htons(ETH_P_MPLS_MC): { 317 struct mpls_label *hdr, _hdr[2]; 318 mpls: 319 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, 320 hlen, &_hdr); 321 if (!hdr) 322 goto out_bad; 323 324 if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >> 325 MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) { 326 if (dissector_uses_key(flow_dissector, 327 FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) { 328 key_keyid = skb_flow_dissector_target(flow_dissector, 329 FLOW_DISSECTOR_KEY_MPLS_ENTROPY, 330 target_container); 331 key_keyid->keyid = hdr[1].entry & 332 htonl(MPLS_LS_LABEL_MASK); 333 } 334 335 goto out_good; 336 } 337 338 goto out_good; 339 } 340 341 case htons(ETH_P_FCOE): 342 if ((hlen - nhoff) < FCOE_HEADER_LEN) 343 goto out_bad; 344 345 nhoff += FCOE_HEADER_LEN; 346 goto out_good; 347 default: 348 goto out_bad; 349 } 350 351 ip_proto_again: 352 switch (ip_proto) { 353 case IPPROTO_GRE: { 354 struct gre_hdr { 355 __be16 flags; 356 __be16 proto; 357 } *hdr, _hdr; 358 359 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 360 if (!hdr) 361 goto out_bad; 362 /* 363 * Only look inside GRE if version zero and no 364 * routing 365 */ 366 if (hdr->flags & (GRE_VERSION | GRE_ROUTING)) 367 break; 368 369 proto = hdr->proto; 370 nhoff += 4; 371 if (hdr->flags & GRE_CSUM) 372 nhoff += 4; 373 if (hdr->flags & GRE_KEY) { 374 const __be32 *keyid; 375 __be32 _keyid; 376 377 keyid = __skb_header_pointer(skb, nhoff, sizeof(_keyid), 378 data, hlen, &_keyid); 379 380 if (!keyid) 381 goto out_bad; 382 383 if (dissector_uses_key(flow_dissector, 384 FLOW_DISSECTOR_KEY_GRE_KEYID)) { 385 key_keyid = skb_flow_dissector_target(flow_dissector, 386 FLOW_DISSECTOR_KEY_GRE_KEYID, 387 target_container); 388 key_keyid->keyid = *keyid; 389 } 390 nhoff += 4; 391 } 392 if (hdr->flags & GRE_SEQ) 393 nhoff += 4; 394 if (proto == htons(ETH_P_TEB)) { 395 const struct ethhdr *eth; 396 struct ethhdr _eth; 397 398 eth = __skb_header_pointer(skb, nhoff, 399 sizeof(_eth), 400 data, hlen, &_eth); 401 if (!eth) 402 goto out_bad; 403 proto = eth->h_proto; 404 nhoff += sizeof(*eth); 405 406 /* Cap headers that we access via pointers at the 407 * end of the Ethernet header as our maximum alignment 408 * at that point is only 2 bytes. 409 */ 410 if (NET_IP_ALIGN) 411 hlen = nhoff; 412 } 413 414 key_control->flags |= FLOW_DIS_ENCAPSULATION; 415 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 416 goto out_good; 417 418 goto again; 419 } 420 case NEXTHDR_HOP: 421 case NEXTHDR_ROUTING: 422 case NEXTHDR_DEST: { 423 u8 _opthdr[2], *opthdr; 424 425 if (proto != htons(ETH_P_IPV6)) 426 break; 427 428 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr), 429 data, hlen, &_opthdr); 430 if (!opthdr) 431 goto out_bad; 432 433 ip_proto = opthdr[0]; 434 nhoff += (opthdr[1] + 1) << 3; 435 436 goto ip_proto_again; 437 } 438 case NEXTHDR_FRAGMENT: { 439 struct frag_hdr _fh, *fh; 440 441 if (proto != htons(ETH_P_IPV6)) 442 break; 443 444 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh), 445 data, hlen, &_fh); 446 447 if (!fh) 448 goto out_bad; 449 450 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 451 452 nhoff += sizeof(_fh); 453 ip_proto = fh->nexthdr; 454 455 if (!(fh->frag_off & htons(IP6_OFFSET))) { 456 key_control->flags |= FLOW_DIS_FIRST_FRAG; 457 if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) 458 goto ip_proto_again; 459 } 460 goto out_good; 461 } 462 case IPPROTO_IPIP: 463 proto = htons(ETH_P_IP); 464 465 key_control->flags |= FLOW_DIS_ENCAPSULATION; 466 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 467 goto out_good; 468 469 goto ip; 470 case IPPROTO_IPV6: 471 proto = htons(ETH_P_IPV6); 472 473 key_control->flags |= FLOW_DIS_ENCAPSULATION; 474 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 475 goto out_good; 476 477 goto ipv6; 478 case IPPROTO_MPLS: 479 proto = htons(ETH_P_MPLS_UC); 480 goto mpls; 481 default: 482 break; 483 } 484 485 if (dissector_uses_key(flow_dissector, 486 FLOW_DISSECTOR_KEY_PORTS)) { 487 key_ports = skb_flow_dissector_target(flow_dissector, 488 FLOW_DISSECTOR_KEY_PORTS, 489 target_container); 490 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto, 491 data, hlen); 492 } 493 494 out_good: 495 ret = true; 496 497 out_bad: 498 key_basic->n_proto = proto; 499 key_basic->ip_proto = ip_proto; 500 key_control->thoff = (u16)nhoff; 501 502 return ret; 503 } 504 EXPORT_SYMBOL(__skb_flow_dissect); 505 506 static u32 hashrnd __read_mostly; 507 static __always_inline void __flow_hash_secret_init(void) 508 { 509 net_get_random_once(&hashrnd, sizeof(hashrnd)); 510 } 511 512 static __always_inline u32 __flow_hash_words(const u32 *words, u32 length, 513 u32 keyval) 514 { 515 return jhash2(words, length, keyval); 516 } 517 518 static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow) 519 { 520 const void *p = flow; 521 522 BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32)); 523 return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET); 524 } 525 526 static inline size_t flow_keys_hash_length(const struct flow_keys *flow) 527 { 528 size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs); 529 BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32)); 530 BUILD_BUG_ON(offsetof(typeof(*flow), addrs) != 531 sizeof(*flow) - sizeof(flow->addrs)); 532 533 switch (flow->control.addr_type) { 534 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 535 diff -= sizeof(flow->addrs.v4addrs); 536 break; 537 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 538 diff -= sizeof(flow->addrs.v6addrs); 539 break; 540 case FLOW_DISSECTOR_KEY_TIPC_ADDRS: 541 diff -= sizeof(flow->addrs.tipcaddrs); 542 break; 543 } 544 return (sizeof(*flow) - diff) / sizeof(u32); 545 } 546 547 __be32 flow_get_u32_src(const struct flow_keys *flow) 548 { 549 switch (flow->control.addr_type) { 550 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 551 return flow->addrs.v4addrs.src; 552 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 553 return (__force __be32)ipv6_addr_hash( 554 &flow->addrs.v6addrs.src); 555 case FLOW_DISSECTOR_KEY_TIPC_ADDRS: 556 return flow->addrs.tipcaddrs.srcnode; 557 default: 558 return 0; 559 } 560 } 561 EXPORT_SYMBOL(flow_get_u32_src); 562 563 __be32 flow_get_u32_dst(const struct flow_keys *flow) 564 { 565 switch (flow->control.addr_type) { 566 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 567 return flow->addrs.v4addrs.dst; 568 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 569 return (__force __be32)ipv6_addr_hash( 570 &flow->addrs.v6addrs.dst); 571 default: 572 return 0; 573 } 574 } 575 EXPORT_SYMBOL(flow_get_u32_dst); 576 577 static inline void __flow_hash_consistentify(struct flow_keys *keys) 578 { 579 int addr_diff, i; 580 581 switch (keys->control.addr_type) { 582 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 583 addr_diff = (__force u32)keys->addrs.v4addrs.dst - 584 (__force u32)keys->addrs.v4addrs.src; 585 if ((addr_diff < 0) || 586 (addr_diff == 0 && 587 ((__force u16)keys->ports.dst < 588 (__force u16)keys->ports.src))) { 589 swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst); 590 swap(keys->ports.src, keys->ports.dst); 591 } 592 break; 593 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 594 addr_diff = memcmp(&keys->addrs.v6addrs.dst, 595 &keys->addrs.v6addrs.src, 596 sizeof(keys->addrs.v6addrs.dst)); 597 if ((addr_diff < 0) || 598 (addr_diff == 0 && 599 ((__force u16)keys->ports.dst < 600 (__force u16)keys->ports.src))) { 601 for (i = 0; i < 4; i++) 602 swap(keys->addrs.v6addrs.src.s6_addr32[i], 603 keys->addrs.v6addrs.dst.s6_addr32[i]); 604 swap(keys->ports.src, keys->ports.dst); 605 } 606 break; 607 } 608 } 609 610 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval) 611 { 612 u32 hash; 613 614 __flow_hash_consistentify(keys); 615 616 hash = __flow_hash_words(flow_keys_hash_start(keys), 617 flow_keys_hash_length(keys), keyval); 618 if (!hash) 619 hash = 1; 620 621 return hash; 622 } 623 624 u32 flow_hash_from_keys(struct flow_keys *keys) 625 { 626 __flow_hash_secret_init(); 627 return __flow_hash_from_keys(keys, hashrnd); 628 } 629 EXPORT_SYMBOL(flow_hash_from_keys); 630 631 static inline u32 ___skb_get_hash(const struct sk_buff *skb, 632 struct flow_keys *keys, u32 keyval) 633 { 634 skb_flow_dissect_flow_keys(skb, keys, 635 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 636 637 return __flow_hash_from_keys(keys, keyval); 638 } 639 640 struct _flow_keys_digest_data { 641 __be16 n_proto; 642 u8 ip_proto; 643 u8 padding; 644 __be32 ports; 645 __be32 src; 646 __be32 dst; 647 }; 648 649 void make_flow_keys_digest(struct flow_keys_digest *digest, 650 const struct flow_keys *flow) 651 { 652 struct _flow_keys_digest_data *data = 653 (struct _flow_keys_digest_data *)digest; 654 655 BUILD_BUG_ON(sizeof(*data) > sizeof(*digest)); 656 657 memset(digest, 0, sizeof(*digest)); 658 659 data->n_proto = flow->basic.n_proto; 660 data->ip_proto = flow->basic.ip_proto; 661 data->ports = flow->ports.ports; 662 data->src = flow->addrs.v4addrs.src; 663 data->dst = flow->addrs.v4addrs.dst; 664 } 665 EXPORT_SYMBOL(make_flow_keys_digest); 666 667 /** 668 * __skb_get_hash: calculate a flow hash 669 * @skb: sk_buff to calculate flow hash from 670 * 671 * This function calculates a flow hash based on src/dst addresses 672 * and src/dst port numbers. Sets hash in skb to non-zero hash value 673 * on success, zero indicates no valid hash. Also, sets l4_hash in skb 674 * if hash is a canonical 4-tuple hash over transport ports. 675 */ 676 void __skb_get_hash(struct sk_buff *skb) 677 { 678 struct flow_keys keys; 679 680 __flow_hash_secret_init(); 681 682 __skb_set_sw_hash(skb, ___skb_get_hash(skb, &keys, hashrnd), 683 flow_keys_have_l4(&keys)); 684 } 685 EXPORT_SYMBOL(__skb_get_hash); 686 687 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb) 688 { 689 struct flow_keys keys; 690 691 return ___skb_get_hash(skb, &keys, perturb); 692 } 693 EXPORT_SYMBOL(skb_get_hash_perturb); 694 695 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6) 696 { 697 struct flow_keys keys; 698 699 memset(&keys, 0, sizeof(keys)); 700 701 memcpy(&keys.addrs.v6addrs.src, &fl6->saddr, 702 sizeof(keys.addrs.v6addrs.src)); 703 memcpy(&keys.addrs.v6addrs.dst, &fl6->daddr, 704 sizeof(keys.addrs.v6addrs.dst)); 705 keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 706 keys.ports.src = fl6->fl6_sport; 707 keys.ports.dst = fl6->fl6_dport; 708 keys.keyid.keyid = fl6->fl6_gre_key; 709 keys.tags.flow_label = (__force u32)fl6->flowlabel; 710 keys.basic.ip_proto = fl6->flowi6_proto; 711 712 __skb_set_sw_hash(skb, flow_hash_from_keys(&keys), 713 flow_keys_have_l4(&keys)); 714 715 return skb->hash; 716 } 717 EXPORT_SYMBOL(__skb_get_hash_flowi6); 718 719 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4) 720 { 721 struct flow_keys keys; 722 723 memset(&keys, 0, sizeof(keys)); 724 725 keys.addrs.v4addrs.src = fl4->saddr; 726 keys.addrs.v4addrs.dst = fl4->daddr; 727 keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 728 keys.ports.src = fl4->fl4_sport; 729 keys.ports.dst = fl4->fl4_dport; 730 keys.keyid.keyid = fl4->fl4_gre_key; 731 keys.basic.ip_proto = fl4->flowi4_proto; 732 733 __skb_set_sw_hash(skb, flow_hash_from_keys(&keys), 734 flow_keys_have_l4(&keys)); 735 736 return skb->hash; 737 } 738 EXPORT_SYMBOL(__skb_get_hash_flowi4); 739 740 u32 __skb_get_poff(const struct sk_buff *skb, void *data, 741 const struct flow_keys *keys, int hlen) 742 { 743 u32 poff = keys->control.thoff; 744 745 /* skip L4 headers for fragments after the first */ 746 if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) && 747 !(keys->control.flags & FLOW_DIS_FIRST_FRAG)) 748 return poff; 749 750 switch (keys->basic.ip_proto) { 751 case IPPROTO_TCP: { 752 /* access doff as u8 to avoid unaligned access */ 753 const u8 *doff; 754 u8 _doff; 755 756 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff), 757 data, hlen, &_doff); 758 if (!doff) 759 return poff; 760 761 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2); 762 break; 763 } 764 case IPPROTO_UDP: 765 case IPPROTO_UDPLITE: 766 poff += sizeof(struct udphdr); 767 break; 768 /* For the rest, we do not really care about header 769 * extensions at this point for now. 770 */ 771 case IPPROTO_ICMP: 772 poff += sizeof(struct icmphdr); 773 break; 774 case IPPROTO_ICMPV6: 775 poff += sizeof(struct icmp6hdr); 776 break; 777 case IPPROTO_IGMP: 778 poff += sizeof(struct igmphdr); 779 break; 780 case IPPROTO_DCCP: 781 poff += sizeof(struct dccp_hdr); 782 break; 783 case IPPROTO_SCTP: 784 poff += sizeof(struct sctphdr); 785 break; 786 } 787 788 return poff; 789 } 790 791 /** 792 * skb_get_poff - get the offset to the payload 793 * @skb: sk_buff to get the payload offset from 794 * 795 * The function will get the offset to the payload as far as it could 796 * be dissected. The main user is currently BPF, so that we can dynamically 797 * truncate packets without needing to push actual payload to the user 798 * space and can analyze headers only, instead. 799 */ 800 u32 skb_get_poff(const struct sk_buff *skb) 801 { 802 struct flow_keys keys; 803 804 if (!skb_flow_dissect_flow_keys(skb, &keys, 0)) 805 return 0; 806 807 return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb)); 808 } 809 810 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys) 811 { 812 memset(keys, 0, sizeof(*keys)); 813 814 memcpy(&keys->addrs.v6addrs.src, &fl6->saddr, 815 sizeof(keys->addrs.v6addrs.src)); 816 memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr, 817 sizeof(keys->addrs.v6addrs.dst)); 818 keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 819 keys->ports.src = fl6->fl6_sport; 820 keys->ports.dst = fl6->fl6_dport; 821 keys->keyid.keyid = fl6->fl6_gre_key; 822 keys->tags.flow_label = (__force u32)fl6->flowlabel; 823 keys->basic.ip_proto = fl6->flowi6_proto; 824 825 return flow_hash_from_keys(keys); 826 } 827 EXPORT_SYMBOL(__get_hash_from_flowi6); 828 829 __u32 __get_hash_from_flowi4(const struct flowi4 *fl4, struct flow_keys *keys) 830 { 831 memset(keys, 0, sizeof(*keys)); 832 833 keys->addrs.v4addrs.src = fl4->saddr; 834 keys->addrs.v4addrs.dst = fl4->daddr; 835 keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 836 keys->ports.src = fl4->fl4_sport; 837 keys->ports.dst = fl4->fl4_dport; 838 keys->keyid.keyid = fl4->fl4_gre_key; 839 keys->basic.ip_proto = fl4->flowi4_proto; 840 841 return flow_hash_from_keys(keys); 842 } 843 EXPORT_SYMBOL(__get_hash_from_flowi4); 844 845 static const struct flow_dissector_key flow_keys_dissector_keys[] = { 846 { 847 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 848 .offset = offsetof(struct flow_keys, control), 849 }, 850 { 851 .key_id = FLOW_DISSECTOR_KEY_BASIC, 852 .offset = offsetof(struct flow_keys, basic), 853 }, 854 { 855 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 856 .offset = offsetof(struct flow_keys, addrs.v4addrs), 857 }, 858 { 859 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 860 .offset = offsetof(struct flow_keys, addrs.v6addrs), 861 }, 862 { 863 .key_id = FLOW_DISSECTOR_KEY_TIPC_ADDRS, 864 .offset = offsetof(struct flow_keys, addrs.tipcaddrs), 865 }, 866 { 867 .key_id = FLOW_DISSECTOR_KEY_PORTS, 868 .offset = offsetof(struct flow_keys, ports), 869 }, 870 { 871 .key_id = FLOW_DISSECTOR_KEY_VLANID, 872 .offset = offsetof(struct flow_keys, tags), 873 }, 874 { 875 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL, 876 .offset = offsetof(struct flow_keys, tags), 877 }, 878 { 879 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID, 880 .offset = offsetof(struct flow_keys, keyid), 881 }, 882 }; 883 884 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = { 885 { 886 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 887 .offset = offsetof(struct flow_keys, control), 888 }, 889 { 890 .key_id = FLOW_DISSECTOR_KEY_BASIC, 891 .offset = offsetof(struct flow_keys, basic), 892 }, 893 }; 894 895 struct flow_dissector flow_keys_dissector __read_mostly; 896 EXPORT_SYMBOL(flow_keys_dissector); 897 898 struct flow_dissector flow_keys_buf_dissector __read_mostly; 899 900 static int __init init_default_flow_dissectors(void) 901 { 902 skb_flow_dissector_init(&flow_keys_dissector, 903 flow_keys_dissector_keys, 904 ARRAY_SIZE(flow_keys_dissector_keys)); 905 skb_flow_dissector_init(&flow_keys_buf_dissector, 906 flow_keys_buf_dissector_keys, 907 ARRAY_SIZE(flow_keys_buf_dissector_keys)); 908 return 0; 909 } 910 911 late_initcall_sync(init_default_flow_dissectors); 912