1 #include <linux/kernel.h> 2 #include <linux/skbuff.h> 3 #include <linux/export.h> 4 #include <linux/ip.h> 5 #include <linux/ipv6.h> 6 #include <linux/if_vlan.h> 7 #include <net/ip.h> 8 #include <net/ipv6.h> 9 #include <net/gre.h> 10 #include <net/pptp.h> 11 #include <linux/igmp.h> 12 #include <linux/icmp.h> 13 #include <linux/sctp.h> 14 #include <linux/dccp.h> 15 #include <linux/if_tunnel.h> 16 #include <linux/if_pppox.h> 17 #include <linux/ppp_defs.h> 18 #include <linux/stddef.h> 19 #include <linux/if_ether.h> 20 #include <linux/mpls.h> 21 #include <net/flow_dissector.h> 22 #include <scsi/fc/fc_fcoe.h> 23 24 static void dissector_set_key(struct flow_dissector *flow_dissector, 25 enum flow_dissector_key_id key_id) 26 { 27 flow_dissector->used_keys |= (1 << key_id); 28 } 29 30 void skb_flow_dissector_init(struct flow_dissector *flow_dissector, 31 const struct flow_dissector_key *key, 32 unsigned int key_count) 33 { 34 unsigned int i; 35 36 memset(flow_dissector, 0, sizeof(*flow_dissector)); 37 38 for (i = 0; i < key_count; i++, key++) { 39 /* User should make sure that every key target offset is withing 40 * boundaries of unsigned short. 41 */ 42 BUG_ON(key->offset > USHRT_MAX); 43 BUG_ON(dissector_uses_key(flow_dissector, 44 key->key_id)); 45 46 dissector_set_key(flow_dissector, key->key_id); 47 flow_dissector->offset[key->key_id] = key->offset; 48 } 49 50 /* Ensure that the dissector always includes control and basic key. 51 * That way we are able to avoid handling lack of these in fast path. 52 */ 53 BUG_ON(!dissector_uses_key(flow_dissector, 54 FLOW_DISSECTOR_KEY_CONTROL)); 55 BUG_ON(!dissector_uses_key(flow_dissector, 56 FLOW_DISSECTOR_KEY_BASIC)); 57 } 58 EXPORT_SYMBOL(skb_flow_dissector_init); 59 60 /** 61 * skb_flow_get_be16 - extract be16 entity 62 * @skb: sk_buff to extract from 63 * @poff: offset to extract at 64 * @data: raw buffer pointer to the packet 65 * @hlen: packet header length 66 * 67 * The function will try to retrieve a be32 entity at 68 * offset poff 69 */ 70 static __be16 skb_flow_get_be16(const struct sk_buff *skb, int poff, 71 void *data, int hlen) 72 { 73 __be16 *u, _u; 74 75 u = __skb_header_pointer(skb, poff, sizeof(_u), data, hlen, &_u); 76 if (u) 77 return *u; 78 79 return 0; 80 } 81 82 /** 83 * __skb_flow_get_ports - extract the upper layer ports and return them 84 * @skb: sk_buff to extract the ports from 85 * @thoff: transport header offset 86 * @ip_proto: protocol for which to get port offset 87 * @data: raw buffer pointer to the packet, if NULL use skb->data 88 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 89 * 90 * The function will try to retrieve the ports at offset thoff + poff where poff 91 * is the protocol port offset returned from proto_ports_offset 92 */ 93 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, 94 void *data, int hlen) 95 { 96 int poff = proto_ports_offset(ip_proto); 97 98 if (!data) { 99 data = skb->data; 100 hlen = skb_headlen(skb); 101 } 102 103 if (poff >= 0) { 104 __be32 *ports, _ports; 105 106 ports = __skb_header_pointer(skb, thoff + poff, 107 sizeof(_ports), data, hlen, &_ports); 108 if (ports) 109 return *ports; 110 } 111 112 return 0; 113 } 114 EXPORT_SYMBOL(__skb_flow_get_ports); 115 116 enum flow_dissect_ret { 117 FLOW_DISSECT_RET_OUT_GOOD, 118 FLOW_DISSECT_RET_OUT_BAD, 119 FLOW_DISSECT_RET_OUT_PROTO_AGAIN, 120 }; 121 122 static enum flow_dissect_ret 123 __skb_flow_dissect_mpls(const struct sk_buff *skb, 124 struct flow_dissector *flow_dissector, 125 void *target_container, void *data, int nhoff, int hlen) 126 { 127 struct flow_dissector_key_keyid *key_keyid; 128 struct mpls_label *hdr, _hdr[2]; 129 130 if (!dissector_uses_key(flow_dissector, 131 FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) 132 return FLOW_DISSECT_RET_OUT_GOOD; 133 134 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, 135 hlen, &_hdr); 136 if (!hdr) 137 return FLOW_DISSECT_RET_OUT_BAD; 138 139 if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >> 140 MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) { 141 key_keyid = skb_flow_dissector_target(flow_dissector, 142 FLOW_DISSECTOR_KEY_MPLS_ENTROPY, 143 target_container); 144 key_keyid->keyid = hdr[1].entry & htonl(MPLS_LS_LABEL_MASK); 145 } 146 return FLOW_DISSECT_RET_OUT_GOOD; 147 } 148 149 static enum flow_dissect_ret 150 __skb_flow_dissect_arp(const struct sk_buff *skb, 151 struct flow_dissector *flow_dissector, 152 void *target_container, void *data, int nhoff, int hlen) 153 { 154 struct flow_dissector_key_arp *key_arp; 155 struct { 156 unsigned char ar_sha[ETH_ALEN]; 157 unsigned char ar_sip[4]; 158 unsigned char ar_tha[ETH_ALEN]; 159 unsigned char ar_tip[4]; 160 } *arp_eth, _arp_eth; 161 const struct arphdr *arp; 162 struct arphdr _arp; 163 164 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ARP)) 165 return FLOW_DISSECT_RET_OUT_GOOD; 166 167 arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data, 168 hlen, &_arp); 169 if (!arp) 170 return FLOW_DISSECT_RET_OUT_BAD; 171 172 if (arp->ar_hrd != htons(ARPHRD_ETHER) || 173 arp->ar_pro != htons(ETH_P_IP) || 174 arp->ar_hln != ETH_ALEN || 175 arp->ar_pln != 4 || 176 (arp->ar_op != htons(ARPOP_REPLY) && 177 arp->ar_op != htons(ARPOP_REQUEST))) 178 return FLOW_DISSECT_RET_OUT_BAD; 179 180 arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp), 181 sizeof(_arp_eth), data, 182 hlen, &_arp_eth); 183 if (!arp_eth) 184 return FLOW_DISSECT_RET_OUT_BAD; 185 186 key_arp = skb_flow_dissector_target(flow_dissector, 187 FLOW_DISSECTOR_KEY_ARP, 188 target_container); 189 190 memcpy(&key_arp->sip, arp_eth->ar_sip, sizeof(key_arp->sip)); 191 memcpy(&key_arp->tip, arp_eth->ar_tip, sizeof(key_arp->tip)); 192 193 /* Only store the lower byte of the opcode; 194 * this covers ARPOP_REPLY and ARPOP_REQUEST. 195 */ 196 key_arp->op = ntohs(arp->ar_op) & 0xff; 197 198 ether_addr_copy(key_arp->sha, arp_eth->ar_sha); 199 ether_addr_copy(key_arp->tha, arp_eth->ar_tha); 200 201 return FLOW_DISSECT_RET_OUT_GOOD; 202 } 203 204 static enum flow_dissect_ret 205 __skb_flow_dissect_gre(const struct sk_buff *skb, 206 struct flow_dissector_key_control *key_control, 207 struct flow_dissector *flow_dissector, 208 void *target_container, void *data, 209 __be16 *p_proto, int *p_nhoff, int *p_hlen, 210 unsigned int flags) 211 { 212 struct flow_dissector_key_keyid *key_keyid; 213 struct gre_base_hdr *hdr, _hdr; 214 int offset = 0; 215 u16 gre_ver; 216 217 hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), 218 data, *p_hlen, &_hdr); 219 if (!hdr) 220 return FLOW_DISSECT_RET_OUT_BAD; 221 222 /* Only look inside GRE without routing */ 223 if (hdr->flags & GRE_ROUTING) 224 return FLOW_DISSECT_RET_OUT_GOOD; 225 226 /* Only look inside GRE for version 0 and 1 */ 227 gre_ver = ntohs(hdr->flags & GRE_VERSION); 228 if (gre_ver > 1) 229 return FLOW_DISSECT_RET_OUT_GOOD; 230 231 *p_proto = hdr->protocol; 232 if (gre_ver) { 233 /* Version1 must be PPTP, and check the flags */ 234 if (!(*p_proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY))) 235 return FLOW_DISSECT_RET_OUT_GOOD; 236 } 237 238 offset += sizeof(struct gre_base_hdr); 239 240 if (hdr->flags & GRE_CSUM) 241 offset += sizeof(((struct gre_full_hdr *) 0)->csum) + 242 sizeof(((struct gre_full_hdr *) 0)->reserved1); 243 244 if (hdr->flags & GRE_KEY) { 245 const __be32 *keyid; 246 __be32 _keyid; 247 248 keyid = __skb_header_pointer(skb, *p_nhoff + offset, 249 sizeof(_keyid), 250 data, *p_hlen, &_keyid); 251 if (!keyid) 252 return FLOW_DISSECT_RET_OUT_BAD; 253 254 if (dissector_uses_key(flow_dissector, 255 FLOW_DISSECTOR_KEY_GRE_KEYID)) { 256 key_keyid = skb_flow_dissector_target(flow_dissector, 257 FLOW_DISSECTOR_KEY_GRE_KEYID, 258 target_container); 259 if (gre_ver == 0) 260 key_keyid->keyid = *keyid; 261 else 262 key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK; 263 } 264 offset += sizeof(((struct gre_full_hdr *) 0)->key); 265 } 266 267 if (hdr->flags & GRE_SEQ) 268 offset += sizeof(((struct pptp_gre_header *) 0)->seq); 269 270 if (gre_ver == 0) { 271 if (*p_proto == htons(ETH_P_TEB)) { 272 const struct ethhdr *eth; 273 struct ethhdr _eth; 274 275 eth = __skb_header_pointer(skb, *p_nhoff + offset, 276 sizeof(_eth), 277 data, *p_hlen, &_eth); 278 if (!eth) 279 return FLOW_DISSECT_RET_OUT_BAD; 280 *p_proto = eth->h_proto; 281 offset += sizeof(*eth); 282 283 /* Cap headers that we access via pointers at the 284 * end of the Ethernet header as our maximum alignment 285 * at that point is only 2 bytes. 286 */ 287 if (NET_IP_ALIGN) 288 *p_hlen = *p_nhoff + offset; 289 } 290 } else { /* version 1, must be PPTP */ 291 u8 _ppp_hdr[PPP_HDRLEN]; 292 u8 *ppp_hdr; 293 294 if (hdr->flags & GRE_ACK) 295 offset += sizeof(((struct pptp_gre_header *) 0)->ack); 296 297 ppp_hdr = __skb_header_pointer(skb, *p_nhoff + offset, 298 sizeof(_ppp_hdr), 299 data, *p_hlen, _ppp_hdr); 300 if (!ppp_hdr) 301 return FLOW_DISSECT_RET_OUT_BAD; 302 303 switch (PPP_PROTOCOL(ppp_hdr)) { 304 case PPP_IP: 305 *p_proto = htons(ETH_P_IP); 306 break; 307 case PPP_IPV6: 308 *p_proto = htons(ETH_P_IPV6); 309 break; 310 default: 311 /* Could probably catch some more like MPLS */ 312 break; 313 } 314 315 offset += PPP_HDRLEN; 316 } 317 318 *p_nhoff += offset; 319 key_control->flags |= FLOW_DIS_ENCAPSULATION; 320 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 321 return FLOW_DISSECT_RET_OUT_GOOD; 322 323 return FLOW_DISSECT_RET_OUT_PROTO_AGAIN; 324 } 325 326 /** 327 * __skb_flow_dissect - extract the flow_keys struct and return it 328 * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified 329 * @flow_dissector: list of keys to dissect 330 * @target_container: target structure to put dissected values into 331 * @data: raw buffer pointer to the packet, if NULL use skb->data 332 * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol 333 * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb) 334 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 335 * 336 * The function will try to retrieve individual keys into target specified 337 * by flow_dissector from either the skbuff or a raw buffer specified by the 338 * rest parameters. 339 * 340 * Caller must take care of zeroing target container memory. 341 */ 342 bool __skb_flow_dissect(const struct sk_buff *skb, 343 struct flow_dissector *flow_dissector, 344 void *target_container, 345 void *data, __be16 proto, int nhoff, int hlen, 346 unsigned int flags) 347 { 348 struct flow_dissector_key_control *key_control; 349 struct flow_dissector_key_basic *key_basic; 350 struct flow_dissector_key_addrs *key_addrs; 351 struct flow_dissector_key_ports *key_ports; 352 struct flow_dissector_key_icmp *key_icmp; 353 struct flow_dissector_key_tags *key_tags; 354 struct flow_dissector_key_vlan *key_vlan; 355 bool skip_vlan = false; 356 u8 ip_proto = 0; 357 bool ret; 358 359 if (!data) { 360 data = skb->data; 361 proto = skb_vlan_tag_present(skb) ? 362 skb->vlan_proto : skb->protocol; 363 nhoff = skb_network_offset(skb); 364 hlen = skb_headlen(skb); 365 } 366 367 /* It is ensured by skb_flow_dissector_init() that control key will 368 * be always present. 369 */ 370 key_control = skb_flow_dissector_target(flow_dissector, 371 FLOW_DISSECTOR_KEY_CONTROL, 372 target_container); 373 374 /* It is ensured by skb_flow_dissector_init() that basic key will 375 * be always present. 376 */ 377 key_basic = skb_flow_dissector_target(flow_dissector, 378 FLOW_DISSECTOR_KEY_BASIC, 379 target_container); 380 381 if (dissector_uses_key(flow_dissector, 382 FLOW_DISSECTOR_KEY_ETH_ADDRS)) { 383 struct ethhdr *eth = eth_hdr(skb); 384 struct flow_dissector_key_eth_addrs *key_eth_addrs; 385 386 key_eth_addrs = skb_flow_dissector_target(flow_dissector, 387 FLOW_DISSECTOR_KEY_ETH_ADDRS, 388 target_container); 389 memcpy(key_eth_addrs, ð->h_dest, sizeof(*key_eth_addrs)); 390 } 391 392 proto_again: 393 switch (proto) { 394 case htons(ETH_P_IP): { 395 const struct iphdr *iph; 396 struct iphdr _iph; 397 ip: 398 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 399 if (!iph || iph->ihl < 5) 400 goto out_bad; 401 nhoff += iph->ihl * 4; 402 403 ip_proto = iph->protocol; 404 405 if (dissector_uses_key(flow_dissector, 406 FLOW_DISSECTOR_KEY_IPV4_ADDRS)) { 407 key_addrs = skb_flow_dissector_target(flow_dissector, 408 FLOW_DISSECTOR_KEY_IPV4_ADDRS, 409 target_container); 410 411 memcpy(&key_addrs->v4addrs, &iph->saddr, 412 sizeof(key_addrs->v4addrs)); 413 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 414 } 415 416 if (ip_is_fragment(iph)) { 417 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 418 419 if (iph->frag_off & htons(IP_OFFSET)) { 420 goto out_good; 421 } else { 422 key_control->flags |= FLOW_DIS_FIRST_FRAG; 423 if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) 424 goto out_good; 425 } 426 } 427 428 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) 429 goto out_good; 430 431 break; 432 } 433 case htons(ETH_P_IPV6): { 434 const struct ipv6hdr *iph; 435 struct ipv6hdr _iph; 436 437 ipv6: 438 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 439 if (!iph) 440 goto out_bad; 441 442 ip_proto = iph->nexthdr; 443 nhoff += sizeof(struct ipv6hdr); 444 445 if (dissector_uses_key(flow_dissector, 446 FLOW_DISSECTOR_KEY_IPV6_ADDRS)) { 447 key_addrs = skb_flow_dissector_target(flow_dissector, 448 FLOW_DISSECTOR_KEY_IPV6_ADDRS, 449 target_container); 450 451 memcpy(&key_addrs->v6addrs, &iph->saddr, 452 sizeof(key_addrs->v6addrs)); 453 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 454 } 455 456 if ((dissector_uses_key(flow_dissector, 457 FLOW_DISSECTOR_KEY_FLOW_LABEL) || 458 (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) && 459 ip6_flowlabel(iph)) { 460 __be32 flow_label = ip6_flowlabel(iph); 461 462 if (dissector_uses_key(flow_dissector, 463 FLOW_DISSECTOR_KEY_FLOW_LABEL)) { 464 key_tags = skb_flow_dissector_target(flow_dissector, 465 FLOW_DISSECTOR_KEY_FLOW_LABEL, 466 target_container); 467 key_tags->flow_label = ntohl(flow_label); 468 } 469 if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) 470 goto out_good; 471 } 472 473 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) 474 goto out_good; 475 476 break; 477 } 478 case htons(ETH_P_8021AD): 479 case htons(ETH_P_8021Q): { 480 const struct vlan_hdr *vlan; 481 struct vlan_hdr _vlan; 482 bool vlan_tag_present = skb && skb_vlan_tag_present(skb); 483 484 if (vlan_tag_present) 485 proto = skb->protocol; 486 487 if (!vlan_tag_present || eth_type_vlan(skb->protocol)) { 488 vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), 489 data, hlen, &_vlan); 490 if (!vlan) 491 goto out_bad; 492 proto = vlan->h_vlan_encapsulated_proto; 493 nhoff += sizeof(*vlan); 494 if (skip_vlan) 495 goto proto_again; 496 } 497 498 skip_vlan = true; 499 if (dissector_uses_key(flow_dissector, 500 FLOW_DISSECTOR_KEY_VLAN)) { 501 key_vlan = skb_flow_dissector_target(flow_dissector, 502 FLOW_DISSECTOR_KEY_VLAN, 503 target_container); 504 505 if (vlan_tag_present) { 506 key_vlan->vlan_id = skb_vlan_tag_get_id(skb); 507 key_vlan->vlan_priority = 508 (skb_vlan_tag_get_prio(skb) >> VLAN_PRIO_SHIFT); 509 } else { 510 key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) & 511 VLAN_VID_MASK; 512 key_vlan->vlan_priority = 513 (ntohs(vlan->h_vlan_TCI) & 514 VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; 515 } 516 } 517 518 goto proto_again; 519 } 520 case htons(ETH_P_PPP_SES): { 521 struct { 522 struct pppoe_hdr hdr; 523 __be16 proto; 524 } *hdr, _hdr; 525 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 526 if (!hdr) 527 goto out_bad; 528 proto = hdr->proto; 529 nhoff += PPPOE_SES_HLEN; 530 switch (proto) { 531 case htons(PPP_IP): 532 goto ip; 533 case htons(PPP_IPV6): 534 goto ipv6; 535 default: 536 goto out_bad; 537 } 538 } 539 case htons(ETH_P_TIPC): { 540 struct { 541 __be32 pre[3]; 542 __be32 srcnode; 543 } *hdr, _hdr; 544 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 545 if (!hdr) 546 goto out_bad; 547 548 if (dissector_uses_key(flow_dissector, 549 FLOW_DISSECTOR_KEY_TIPC_ADDRS)) { 550 key_addrs = skb_flow_dissector_target(flow_dissector, 551 FLOW_DISSECTOR_KEY_TIPC_ADDRS, 552 target_container); 553 key_addrs->tipcaddrs.srcnode = hdr->srcnode; 554 key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS; 555 } 556 goto out_good; 557 } 558 559 case htons(ETH_P_MPLS_UC): 560 case htons(ETH_P_MPLS_MC): 561 mpls: 562 switch (__skb_flow_dissect_mpls(skb, flow_dissector, 563 target_container, data, 564 nhoff, hlen)) { 565 case FLOW_DISSECT_RET_OUT_GOOD: 566 goto out_good; 567 case FLOW_DISSECT_RET_OUT_BAD: 568 default: 569 goto out_bad; 570 } 571 case htons(ETH_P_FCOE): 572 if ((hlen - nhoff) < FCOE_HEADER_LEN) 573 goto out_bad; 574 575 nhoff += FCOE_HEADER_LEN; 576 goto out_good; 577 578 case htons(ETH_P_ARP): 579 case htons(ETH_P_RARP): 580 switch (__skb_flow_dissect_arp(skb, flow_dissector, 581 target_container, data, 582 nhoff, hlen)) { 583 case FLOW_DISSECT_RET_OUT_GOOD: 584 goto out_good; 585 case FLOW_DISSECT_RET_OUT_BAD: 586 default: 587 goto out_bad; 588 } 589 default: 590 goto out_bad; 591 } 592 593 ip_proto_again: 594 switch (ip_proto) { 595 case IPPROTO_GRE: 596 switch (__skb_flow_dissect_gre(skb, key_control, flow_dissector, 597 target_container, data, 598 &proto, &nhoff, &hlen, flags)) { 599 case FLOW_DISSECT_RET_OUT_GOOD: 600 goto out_good; 601 case FLOW_DISSECT_RET_OUT_BAD: 602 goto out_bad; 603 case FLOW_DISSECT_RET_OUT_PROTO_AGAIN: 604 goto proto_again; 605 } 606 case NEXTHDR_HOP: 607 case NEXTHDR_ROUTING: 608 case NEXTHDR_DEST: { 609 u8 _opthdr[2], *opthdr; 610 611 if (proto != htons(ETH_P_IPV6)) 612 break; 613 614 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr), 615 data, hlen, &_opthdr); 616 if (!opthdr) 617 goto out_bad; 618 619 ip_proto = opthdr[0]; 620 nhoff += (opthdr[1] + 1) << 3; 621 622 goto ip_proto_again; 623 } 624 case NEXTHDR_FRAGMENT: { 625 struct frag_hdr _fh, *fh; 626 627 if (proto != htons(ETH_P_IPV6)) 628 break; 629 630 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh), 631 data, hlen, &_fh); 632 633 if (!fh) 634 goto out_bad; 635 636 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 637 638 nhoff += sizeof(_fh); 639 ip_proto = fh->nexthdr; 640 641 if (!(fh->frag_off & htons(IP6_OFFSET))) { 642 key_control->flags |= FLOW_DIS_FIRST_FRAG; 643 if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) 644 goto ip_proto_again; 645 } 646 goto out_good; 647 } 648 case IPPROTO_IPIP: 649 proto = htons(ETH_P_IP); 650 651 key_control->flags |= FLOW_DIS_ENCAPSULATION; 652 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 653 goto out_good; 654 655 goto ip; 656 case IPPROTO_IPV6: 657 proto = htons(ETH_P_IPV6); 658 659 key_control->flags |= FLOW_DIS_ENCAPSULATION; 660 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 661 goto out_good; 662 663 goto ipv6; 664 case IPPROTO_MPLS: 665 proto = htons(ETH_P_MPLS_UC); 666 goto mpls; 667 default: 668 break; 669 } 670 671 if (dissector_uses_key(flow_dissector, 672 FLOW_DISSECTOR_KEY_PORTS)) { 673 key_ports = skb_flow_dissector_target(flow_dissector, 674 FLOW_DISSECTOR_KEY_PORTS, 675 target_container); 676 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto, 677 data, hlen); 678 } 679 680 if (dissector_uses_key(flow_dissector, 681 FLOW_DISSECTOR_KEY_ICMP)) { 682 key_icmp = skb_flow_dissector_target(flow_dissector, 683 FLOW_DISSECTOR_KEY_ICMP, 684 target_container); 685 key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen); 686 } 687 688 out_good: 689 ret = true; 690 691 key_control->thoff = (u16)nhoff; 692 out: 693 key_basic->n_proto = proto; 694 key_basic->ip_proto = ip_proto; 695 696 return ret; 697 698 out_bad: 699 ret = false; 700 key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen); 701 goto out; 702 } 703 EXPORT_SYMBOL(__skb_flow_dissect); 704 705 static u32 hashrnd __read_mostly; 706 static __always_inline void __flow_hash_secret_init(void) 707 { 708 net_get_random_once(&hashrnd, sizeof(hashrnd)); 709 } 710 711 static __always_inline u32 __flow_hash_words(const u32 *words, u32 length, 712 u32 keyval) 713 { 714 return jhash2(words, length, keyval); 715 } 716 717 static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow) 718 { 719 const void *p = flow; 720 721 BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32)); 722 return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET); 723 } 724 725 static inline size_t flow_keys_hash_length(const struct flow_keys *flow) 726 { 727 size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs); 728 BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32)); 729 BUILD_BUG_ON(offsetof(typeof(*flow), addrs) != 730 sizeof(*flow) - sizeof(flow->addrs)); 731 732 switch (flow->control.addr_type) { 733 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 734 diff -= sizeof(flow->addrs.v4addrs); 735 break; 736 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 737 diff -= sizeof(flow->addrs.v6addrs); 738 break; 739 case FLOW_DISSECTOR_KEY_TIPC_ADDRS: 740 diff -= sizeof(flow->addrs.tipcaddrs); 741 break; 742 } 743 return (sizeof(*flow) - diff) / sizeof(u32); 744 } 745 746 __be32 flow_get_u32_src(const struct flow_keys *flow) 747 { 748 switch (flow->control.addr_type) { 749 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 750 return flow->addrs.v4addrs.src; 751 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 752 return (__force __be32)ipv6_addr_hash( 753 &flow->addrs.v6addrs.src); 754 case FLOW_DISSECTOR_KEY_TIPC_ADDRS: 755 return flow->addrs.tipcaddrs.srcnode; 756 default: 757 return 0; 758 } 759 } 760 EXPORT_SYMBOL(flow_get_u32_src); 761 762 __be32 flow_get_u32_dst(const struct flow_keys *flow) 763 { 764 switch (flow->control.addr_type) { 765 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 766 return flow->addrs.v4addrs.dst; 767 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 768 return (__force __be32)ipv6_addr_hash( 769 &flow->addrs.v6addrs.dst); 770 default: 771 return 0; 772 } 773 } 774 EXPORT_SYMBOL(flow_get_u32_dst); 775 776 static inline void __flow_hash_consistentify(struct flow_keys *keys) 777 { 778 int addr_diff, i; 779 780 switch (keys->control.addr_type) { 781 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 782 addr_diff = (__force u32)keys->addrs.v4addrs.dst - 783 (__force u32)keys->addrs.v4addrs.src; 784 if ((addr_diff < 0) || 785 (addr_diff == 0 && 786 ((__force u16)keys->ports.dst < 787 (__force u16)keys->ports.src))) { 788 swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst); 789 swap(keys->ports.src, keys->ports.dst); 790 } 791 break; 792 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 793 addr_diff = memcmp(&keys->addrs.v6addrs.dst, 794 &keys->addrs.v6addrs.src, 795 sizeof(keys->addrs.v6addrs.dst)); 796 if ((addr_diff < 0) || 797 (addr_diff == 0 && 798 ((__force u16)keys->ports.dst < 799 (__force u16)keys->ports.src))) { 800 for (i = 0; i < 4; i++) 801 swap(keys->addrs.v6addrs.src.s6_addr32[i], 802 keys->addrs.v6addrs.dst.s6_addr32[i]); 803 swap(keys->ports.src, keys->ports.dst); 804 } 805 break; 806 } 807 } 808 809 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval) 810 { 811 u32 hash; 812 813 __flow_hash_consistentify(keys); 814 815 hash = __flow_hash_words(flow_keys_hash_start(keys), 816 flow_keys_hash_length(keys), keyval); 817 if (!hash) 818 hash = 1; 819 820 return hash; 821 } 822 823 u32 flow_hash_from_keys(struct flow_keys *keys) 824 { 825 __flow_hash_secret_init(); 826 return __flow_hash_from_keys(keys, hashrnd); 827 } 828 EXPORT_SYMBOL(flow_hash_from_keys); 829 830 static inline u32 ___skb_get_hash(const struct sk_buff *skb, 831 struct flow_keys *keys, u32 keyval) 832 { 833 skb_flow_dissect_flow_keys(skb, keys, 834 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 835 836 return __flow_hash_from_keys(keys, keyval); 837 } 838 839 struct _flow_keys_digest_data { 840 __be16 n_proto; 841 u8 ip_proto; 842 u8 padding; 843 __be32 ports; 844 __be32 src; 845 __be32 dst; 846 }; 847 848 void make_flow_keys_digest(struct flow_keys_digest *digest, 849 const struct flow_keys *flow) 850 { 851 struct _flow_keys_digest_data *data = 852 (struct _flow_keys_digest_data *)digest; 853 854 BUILD_BUG_ON(sizeof(*data) > sizeof(*digest)); 855 856 memset(digest, 0, sizeof(*digest)); 857 858 data->n_proto = flow->basic.n_proto; 859 data->ip_proto = flow->basic.ip_proto; 860 data->ports = flow->ports.ports; 861 data->src = flow->addrs.v4addrs.src; 862 data->dst = flow->addrs.v4addrs.dst; 863 } 864 EXPORT_SYMBOL(make_flow_keys_digest); 865 866 static struct flow_dissector flow_keys_dissector_symmetric __read_mostly; 867 868 u32 __skb_get_hash_symmetric(const struct sk_buff *skb) 869 { 870 struct flow_keys keys; 871 872 __flow_hash_secret_init(); 873 874 memset(&keys, 0, sizeof(keys)); 875 __skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys, 876 NULL, 0, 0, 0, 877 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 878 879 return __flow_hash_from_keys(&keys, hashrnd); 880 } 881 EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric); 882 883 /** 884 * __skb_get_hash: calculate a flow hash 885 * @skb: sk_buff to calculate flow hash from 886 * 887 * This function calculates a flow hash based on src/dst addresses 888 * and src/dst port numbers. Sets hash in skb to non-zero hash value 889 * on success, zero indicates no valid hash. Also, sets l4_hash in skb 890 * if hash is a canonical 4-tuple hash over transport ports. 891 */ 892 void __skb_get_hash(struct sk_buff *skb) 893 { 894 struct flow_keys keys; 895 u32 hash; 896 897 __flow_hash_secret_init(); 898 899 hash = ___skb_get_hash(skb, &keys, hashrnd); 900 901 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys)); 902 } 903 EXPORT_SYMBOL(__skb_get_hash); 904 905 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb) 906 { 907 struct flow_keys keys; 908 909 return ___skb_get_hash(skb, &keys, perturb); 910 } 911 EXPORT_SYMBOL(skb_get_hash_perturb); 912 913 __u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6) 914 { 915 struct flow_keys keys; 916 917 memset(&keys, 0, sizeof(keys)); 918 919 memcpy(&keys.addrs.v6addrs.src, &fl6->saddr, 920 sizeof(keys.addrs.v6addrs.src)); 921 memcpy(&keys.addrs.v6addrs.dst, &fl6->daddr, 922 sizeof(keys.addrs.v6addrs.dst)); 923 keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 924 keys.ports.src = fl6->fl6_sport; 925 keys.ports.dst = fl6->fl6_dport; 926 keys.keyid.keyid = fl6->fl6_gre_key; 927 keys.tags.flow_label = (__force u32)fl6->flowlabel; 928 keys.basic.ip_proto = fl6->flowi6_proto; 929 930 __skb_set_sw_hash(skb, flow_hash_from_keys(&keys), 931 flow_keys_have_l4(&keys)); 932 933 return skb->hash; 934 } 935 EXPORT_SYMBOL(__skb_get_hash_flowi6); 936 937 __u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4) 938 { 939 struct flow_keys keys; 940 941 memset(&keys, 0, sizeof(keys)); 942 943 keys.addrs.v4addrs.src = fl4->saddr; 944 keys.addrs.v4addrs.dst = fl4->daddr; 945 keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 946 keys.ports.src = fl4->fl4_sport; 947 keys.ports.dst = fl4->fl4_dport; 948 keys.keyid.keyid = fl4->fl4_gre_key; 949 keys.basic.ip_proto = fl4->flowi4_proto; 950 951 __skb_set_sw_hash(skb, flow_hash_from_keys(&keys), 952 flow_keys_have_l4(&keys)); 953 954 return skb->hash; 955 } 956 EXPORT_SYMBOL(__skb_get_hash_flowi4); 957 958 u32 __skb_get_poff(const struct sk_buff *skb, void *data, 959 const struct flow_keys *keys, int hlen) 960 { 961 u32 poff = keys->control.thoff; 962 963 /* skip L4 headers for fragments after the first */ 964 if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) && 965 !(keys->control.flags & FLOW_DIS_FIRST_FRAG)) 966 return poff; 967 968 switch (keys->basic.ip_proto) { 969 case IPPROTO_TCP: { 970 /* access doff as u8 to avoid unaligned access */ 971 const u8 *doff; 972 u8 _doff; 973 974 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff), 975 data, hlen, &_doff); 976 if (!doff) 977 return poff; 978 979 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2); 980 break; 981 } 982 case IPPROTO_UDP: 983 case IPPROTO_UDPLITE: 984 poff += sizeof(struct udphdr); 985 break; 986 /* For the rest, we do not really care about header 987 * extensions at this point for now. 988 */ 989 case IPPROTO_ICMP: 990 poff += sizeof(struct icmphdr); 991 break; 992 case IPPROTO_ICMPV6: 993 poff += sizeof(struct icmp6hdr); 994 break; 995 case IPPROTO_IGMP: 996 poff += sizeof(struct igmphdr); 997 break; 998 case IPPROTO_DCCP: 999 poff += sizeof(struct dccp_hdr); 1000 break; 1001 case IPPROTO_SCTP: 1002 poff += sizeof(struct sctphdr); 1003 break; 1004 } 1005 1006 return poff; 1007 } 1008 1009 /** 1010 * skb_get_poff - get the offset to the payload 1011 * @skb: sk_buff to get the payload offset from 1012 * 1013 * The function will get the offset to the payload as far as it could 1014 * be dissected. The main user is currently BPF, so that we can dynamically 1015 * truncate packets without needing to push actual payload to the user 1016 * space and can analyze headers only, instead. 1017 */ 1018 u32 skb_get_poff(const struct sk_buff *skb) 1019 { 1020 struct flow_keys keys; 1021 1022 if (!skb_flow_dissect_flow_keys(skb, &keys, 0)) 1023 return 0; 1024 1025 return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb)); 1026 } 1027 1028 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys) 1029 { 1030 memset(keys, 0, sizeof(*keys)); 1031 1032 memcpy(&keys->addrs.v6addrs.src, &fl6->saddr, 1033 sizeof(keys->addrs.v6addrs.src)); 1034 memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr, 1035 sizeof(keys->addrs.v6addrs.dst)); 1036 keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1037 keys->ports.src = fl6->fl6_sport; 1038 keys->ports.dst = fl6->fl6_dport; 1039 keys->keyid.keyid = fl6->fl6_gre_key; 1040 keys->tags.flow_label = (__force u32)fl6->flowlabel; 1041 keys->basic.ip_proto = fl6->flowi6_proto; 1042 1043 return flow_hash_from_keys(keys); 1044 } 1045 EXPORT_SYMBOL(__get_hash_from_flowi6); 1046 1047 __u32 __get_hash_from_flowi4(const struct flowi4 *fl4, struct flow_keys *keys) 1048 { 1049 memset(keys, 0, sizeof(*keys)); 1050 1051 keys->addrs.v4addrs.src = fl4->saddr; 1052 keys->addrs.v4addrs.dst = fl4->daddr; 1053 keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1054 keys->ports.src = fl4->fl4_sport; 1055 keys->ports.dst = fl4->fl4_dport; 1056 keys->keyid.keyid = fl4->fl4_gre_key; 1057 keys->basic.ip_proto = fl4->flowi4_proto; 1058 1059 return flow_hash_from_keys(keys); 1060 } 1061 EXPORT_SYMBOL(__get_hash_from_flowi4); 1062 1063 static const struct flow_dissector_key flow_keys_dissector_keys[] = { 1064 { 1065 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1066 .offset = offsetof(struct flow_keys, control), 1067 }, 1068 { 1069 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1070 .offset = offsetof(struct flow_keys, basic), 1071 }, 1072 { 1073 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1074 .offset = offsetof(struct flow_keys, addrs.v4addrs), 1075 }, 1076 { 1077 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1078 .offset = offsetof(struct flow_keys, addrs.v6addrs), 1079 }, 1080 { 1081 .key_id = FLOW_DISSECTOR_KEY_TIPC_ADDRS, 1082 .offset = offsetof(struct flow_keys, addrs.tipcaddrs), 1083 }, 1084 { 1085 .key_id = FLOW_DISSECTOR_KEY_PORTS, 1086 .offset = offsetof(struct flow_keys, ports), 1087 }, 1088 { 1089 .key_id = FLOW_DISSECTOR_KEY_VLAN, 1090 .offset = offsetof(struct flow_keys, vlan), 1091 }, 1092 { 1093 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL, 1094 .offset = offsetof(struct flow_keys, tags), 1095 }, 1096 { 1097 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID, 1098 .offset = offsetof(struct flow_keys, keyid), 1099 }, 1100 }; 1101 1102 static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = { 1103 { 1104 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1105 .offset = offsetof(struct flow_keys, control), 1106 }, 1107 { 1108 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1109 .offset = offsetof(struct flow_keys, basic), 1110 }, 1111 { 1112 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1113 .offset = offsetof(struct flow_keys, addrs.v4addrs), 1114 }, 1115 { 1116 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1117 .offset = offsetof(struct flow_keys, addrs.v6addrs), 1118 }, 1119 { 1120 .key_id = FLOW_DISSECTOR_KEY_PORTS, 1121 .offset = offsetof(struct flow_keys, ports), 1122 }, 1123 }; 1124 1125 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = { 1126 { 1127 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1128 .offset = offsetof(struct flow_keys, control), 1129 }, 1130 { 1131 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1132 .offset = offsetof(struct flow_keys, basic), 1133 }, 1134 }; 1135 1136 struct flow_dissector flow_keys_dissector __read_mostly; 1137 EXPORT_SYMBOL(flow_keys_dissector); 1138 1139 struct flow_dissector flow_keys_buf_dissector __read_mostly; 1140 1141 static int __init init_default_flow_dissectors(void) 1142 { 1143 skb_flow_dissector_init(&flow_keys_dissector, 1144 flow_keys_dissector_keys, 1145 ARRAY_SIZE(flow_keys_dissector_keys)); 1146 skb_flow_dissector_init(&flow_keys_dissector_symmetric, 1147 flow_keys_dissector_symmetric_keys, 1148 ARRAY_SIZE(flow_keys_dissector_symmetric_keys)); 1149 skb_flow_dissector_init(&flow_keys_buf_dissector, 1150 flow_keys_buf_dissector_keys, 1151 ARRAY_SIZE(flow_keys_buf_dissector_keys)); 1152 return 0; 1153 } 1154 1155 core_initcall(init_default_flow_dissectors); 1156