1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/kernel.h> 3 #include <linux/skbuff.h> 4 #include <linux/export.h> 5 #include <linux/ip.h> 6 #include <linux/ipv6.h> 7 #include <linux/if_vlan.h> 8 #include <net/dsa.h> 9 #include <net/dst_metadata.h> 10 #include <net/ip.h> 11 #include <net/ipv6.h> 12 #include <net/gre.h> 13 #include <net/pptp.h> 14 #include <net/tipc.h> 15 #include <linux/igmp.h> 16 #include <linux/icmp.h> 17 #include <linux/sctp.h> 18 #include <linux/dccp.h> 19 #include <linux/if_tunnel.h> 20 #include <linux/if_pppox.h> 21 #include <linux/ppp_defs.h> 22 #include <linux/stddef.h> 23 #include <linux/if_ether.h> 24 #include <linux/mpls.h> 25 #include <linux/tcp.h> 26 #include <net/flow_dissector.h> 27 #include <scsi/fc/fc_fcoe.h> 28 #include <uapi/linux/batadv_packet.h> 29 #include <linux/bpf.h> 30 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 31 #include <net/netfilter/nf_conntrack_core.h> 32 #include <net/netfilter/nf_conntrack_labels.h> 33 #endif 34 #include <linux/bpf-netns.h> 35 36 static void dissector_set_key(struct flow_dissector *flow_dissector, 37 enum flow_dissector_key_id key_id) 38 { 39 flow_dissector->used_keys |= (1 << key_id); 40 } 41 42 void skb_flow_dissector_init(struct flow_dissector *flow_dissector, 43 const struct flow_dissector_key *key, 44 unsigned int key_count) 45 { 46 unsigned int i; 47 48 memset(flow_dissector, 0, sizeof(*flow_dissector)); 49 50 for (i = 0; i < key_count; i++, key++) { 51 /* User should make sure that every key target offset is withing 52 * boundaries of unsigned short. 53 */ 54 BUG_ON(key->offset > USHRT_MAX); 55 BUG_ON(dissector_uses_key(flow_dissector, 56 key->key_id)); 57 58 dissector_set_key(flow_dissector, key->key_id); 59 flow_dissector->offset[key->key_id] = key->offset; 60 } 61 62 /* Ensure that the dissector always includes control and basic key. 63 * That way we are able to avoid handling lack of these in fast path. 64 */ 65 BUG_ON(!dissector_uses_key(flow_dissector, 66 FLOW_DISSECTOR_KEY_CONTROL)); 67 BUG_ON(!dissector_uses_key(flow_dissector, 68 FLOW_DISSECTOR_KEY_BASIC)); 69 } 70 EXPORT_SYMBOL(skb_flow_dissector_init); 71 72 #ifdef CONFIG_BPF_SYSCALL 73 int flow_dissector_bpf_prog_attach_check(struct net *net, 74 struct bpf_prog *prog) 75 { 76 enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR; 77 78 if (net == &init_net) { 79 /* BPF flow dissector in the root namespace overrides 80 * any per-net-namespace one. When attaching to root, 81 * make sure we don't have any BPF program attached 82 * to the non-root namespaces. 83 */ 84 struct net *ns; 85 86 for_each_net(ns) { 87 if (ns == &init_net) 88 continue; 89 if (rcu_access_pointer(ns->bpf.run_array[type])) 90 return -EEXIST; 91 } 92 } else { 93 /* Make sure root flow dissector is not attached 94 * when attaching to the non-root namespace. 95 */ 96 if (rcu_access_pointer(init_net.bpf.run_array[type])) 97 return -EEXIST; 98 } 99 100 return 0; 101 } 102 #endif /* CONFIG_BPF_SYSCALL */ 103 104 /** 105 * __skb_flow_get_ports - extract the upper layer ports and return them 106 * @skb: sk_buff to extract the ports from 107 * @thoff: transport header offset 108 * @ip_proto: protocol for which to get port offset 109 * @data: raw buffer pointer to the packet, if NULL use skb->data 110 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 111 * 112 * The function will try to retrieve the ports at offset thoff + poff where poff 113 * is the protocol port offset returned from proto_ports_offset 114 */ 115 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, 116 void *data, int hlen) 117 { 118 int poff = proto_ports_offset(ip_proto); 119 120 if (!data) { 121 data = skb->data; 122 hlen = skb_headlen(skb); 123 } 124 125 if (poff >= 0) { 126 __be32 *ports, _ports; 127 128 ports = __skb_header_pointer(skb, thoff + poff, 129 sizeof(_ports), data, hlen, &_ports); 130 if (ports) 131 return *ports; 132 } 133 134 return 0; 135 } 136 EXPORT_SYMBOL(__skb_flow_get_ports); 137 138 static bool icmp_has_id(u8 type) 139 { 140 switch (type) { 141 case ICMP_ECHO: 142 case ICMP_ECHOREPLY: 143 case ICMP_TIMESTAMP: 144 case ICMP_TIMESTAMPREPLY: 145 case ICMPV6_ECHO_REQUEST: 146 case ICMPV6_ECHO_REPLY: 147 return true; 148 } 149 150 return false; 151 } 152 153 /** 154 * skb_flow_get_icmp_tci - extract ICMP(6) Type, Code and Identifier fields 155 * @skb: sk_buff to extract from 156 * @key_icmp: struct flow_dissector_key_icmp to fill 157 * @data: raw buffer pointer to the packet 158 * @thoff: offset to extract at 159 * @hlen: packet header length 160 */ 161 void skb_flow_get_icmp_tci(const struct sk_buff *skb, 162 struct flow_dissector_key_icmp *key_icmp, 163 void *data, int thoff, int hlen) 164 { 165 struct icmphdr *ih, _ih; 166 167 ih = __skb_header_pointer(skb, thoff, sizeof(_ih), data, hlen, &_ih); 168 if (!ih) 169 return; 170 171 key_icmp->type = ih->type; 172 key_icmp->code = ih->code; 173 174 /* As we use 0 to signal that the Id field is not present, 175 * avoid confusion with packets without such field 176 */ 177 if (icmp_has_id(ih->type)) 178 key_icmp->id = ih->un.echo.id ? : 1; 179 else 180 key_icmp->id = 0; 181 } 182 EXPORT_SYMBOL(skb_flow_get_icmp_tci); 183 184 /* If FLOW_DISSECTOR_KEY_ICMP is set, dissect an ICMP packet 185 * using skb_flow_get_icmp_tci(). 186 */ 187 static void __skb_flow_dissect_icmp(const struct sk_buff *skb, 188 struct flow_dissector *flow_dissector, 189 void *target_container, 190 void *data, int thoff, int hlen) 191 { 192 struct flow_dissector_key_icmp *key_icmp; 193 194 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ICMP)) 195 return; 196 197 key_icmp = skb_flow_dissector_target(flow_dissector, 198 FLOW_DISSECTOR_KEY_ICMP, 199 target_container); 200 201 skb_flow_get_icmp_tci(skb, key_icmp, data, thoff, hlen); 202 } 203 204 void skb_flow_dissect_meta(const struct sk_buff *skb, 205 struct flow_dissector *flow_dissector, 206 void *target_container) 207 { 208 struct flow_dissector_key_meta *meta; 209 210 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_META)) 211 return; 212 213 meta = skb_flow_dissector_target(flow_dissector, 214 FLOW_DISSECTOR_KEY_META, 215 target_container); 216 meta->ingress_ifindex = skb->skb_iif; 217 } 218 EXPORT_SYMBOL(skb_flow_dissect_meta); 219 220 static void 221 skb_flow_dissect_set_enc_addr_type(enum flow_dissector_key_id type, 222 struct flow_dissector *flow_dissector, 223 void *target_container) 224 { 225 struct flow_dissector_key_control *ctrl; 226 227 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_CONTROL)) 228 return; 229 230 ctrl = skb_flow_dissector_target(flow_dissector, 231 FLOW_DISSECTOR_KEY_ENC_CONTROL, 232 target_container); 233 ctrl->addr_type = type; 234 } 235 236 void 237 skb_flow_dissect_ct(const struct sk_buff *skb, 238 struct flow_dissector *flow_dissector, 239 void *target_container, 240 u16 *ctinfo_map, 241 size_t mapsize) 242 { 243 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 244 struct flow_dissector_key_ct *key; 245 enum ip_conntrack_info ctinfo; 246 struct nf_conn_labels *cl; 247 struct nf_conn *ct; 248 249 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_CT)) 250 return; 251 252 ct = nf_ct_get(skb, &ctinfo); 253 if (!ct) 254 return; 255 256 key = skb_flow_dissector_target(flow_dissector, 257 FLOW_DISSECTOR_KEY_CT, 258 target_container); 259 260 if (ctinfo < mapsize) 261 key->ct_state = ctinfo_map[ctinfo]; 262 #if IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) 263 key->ct_zone = ct->zone.id; 264 #endif 265 #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) 266 key->ct_mark = ct->mark; 267 #endif 268 269 cl = nf_ct_labels_find(ct); 270 if (cl) 271 memcpy(key->ct_labels, cl->bits, sizeof(key->ct_labels)); 272 #endif /* CONFIG_NF_CONNTRACK */ 273 } 274 EXPORT_SYMBOL(skb_flow_dissect_ct); 275 276 void 277 skb_flow_dissect_tunnel_info(const struct sk_buff *skb, 278 struct flow_dissector *flow_dissector, 279 void *target_container) 280 { 281 struct ip_tunnel_info *info; 282 struct ip_tunnel_key *key; 283 284 /* A quick check to see if there might be something to do. */ 285 if (!dissector_uses_key(flow_dissector, 286 FLOW_DISSECTOR_KEY_ENC_KEYID) && 287 !dissector_uses_key(flow_dissector, 288 FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS) && 289 !dissector_uses_key(flow_dissector, 290 FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS) && 291 !dissector_uses_key(flow_dissector, 292 FLOW_DISSECTOR_KEY_ENC_CONTROL) && 293 !dissector_uses_key(flow_dissector, 294 FLOW_DISSECTOR_KEY_ENC_PORTS) && 295 !dissector_uses_key(flow_dissector, 296 FLOW_DISSECTOR_KEY_ENC_IP) && 297 !dissector_uses_key(flow_dissector, 298 FLOW_DISSECTOR_KEY_ENC_OPTS)) 299 return; 300 301 info = skb_tunnel_info(skb); 302 if (!info) 303 return; 304 305 key = &info->key; 306 307 switch (ip_tunnel_info_af(info)) { 308 case AF_INET: 309 skb_flow_dissect_set_enc_addr_type(FLOW_DISSECTOR_KEY_IPV4_ADDRS, 310 flow_dissector, 311 target_container); 312 if (dissector_uses_key(flow_dissector, 313 FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS)) { 314 struct flow_dissector_key_ipv4_addrs *ipv4; 315 316 ipv4 = skb_flow_dissector_target(flow_dissector, 317 FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS, 318 target_container); 319 ipv4->src = key->u.ipv4.src; 320 ipv4->dst = key->u.ipv4.dst; 321 } 322 break; 323 case AF_INET6: 324 skb_flow_dissect_set_enc_addr_type(FLOW_DISSECTOR_KEY_IPV6_ADDRS, 325 flow_dissector, 326 target_container); 327 if (dissector_uses_key(flow_dissector, 328 FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS)) { 329 struct flow_dissector_key_ipv6_addrs *ipv6; 330 331 ipv6 = skb_flow_dissector_target(flow_dissector, 332 FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS, 333 target_container); 334 ipv6->src = key->u.ipv6.src; 335 ipv6->dst = key->u.ipv6.dst; 336 } 337 break; 338 } 339 340 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_KEYID)) { 341 struct flow_dissector_key_keyid *keyid; 342 343 keyid = skb_flow_dissector_target(flow_dissector, 344 FLOW_DISSECTOR_KEY_ENC_KEYID, 345 target_container); 346 keyid->keyid = tunnel_id_to_key32(key->tun_id); 347 } 348 349 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_PORTS)) { 350 struct flow_dissector_key_ports *tp; 351 352 tp = skb_flow_dissector_target(flow_dissector, 353 FLOW_DISSECTOR_KEY_ENC_PORTS, 354 target_container); 355 tp->src = key->tp_src; 356 tp->dst = key->tp_dst; 357 } 358 359 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_IP)) { 360 struct flow_dissector_key_ip *ip; 361 362 ip = skb_flow_dissector_target(flow_dissector, 363 FLOW_DISSECTOR_KEY_ENC_IP, 364 target_container); 365 ip->tos = key->tos; 366 ip->ttl = key->ttl; 367 } 368 369 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_OPTS)) { 370 struct flow_dissector_key_enc_opts *enc_opt; 371 372 enc_opt = skb_flow_dissector_target(flow_dissector, 373 FLOW_DISSECTOR_KEY_ENC_OPTS, 374 target_container); 375 376 if (info->options_len) { 377 enc_opt->len = info->options_len; 378 ip_tunnel_info_opts_get(enc_opt->data, info); 379 enc_opt->dst_opt_type = info->key.tun_flags & 380 TUNNEL_OPTIONS_PRESENT; 381 } 382 } 383 } 384 EXPORT_SYMBOL(skb_flow_dissect_tunnel_info); 385 386 void skb_flow_dissect_hash(const struct sk_buff *skb, 387 struct flow_dissector *flow_dissector, 388 void *target_container) 389 { 390 struct flow_dissector_key_hash *key; 391 392 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_HASH)) 393 return; 394 395 key = skb_flow_dissector_target(flow_dissector, 396 FLOW_DISSECTOR_KEY_HASH, 397 target_container); 398 399 key->hash = skb_get_hash_raw(skb); 400 } 401 EXPORT_SYMBOL(skb_flow_dissect_hash); 402 403 static enum flow_dissect_ret 404 __skb_flow_dissect_mpls(const struct sk_buff *skb, 405 struct flow_dissector *flow_dissector, 406 void *target_container, void *data, int nhoff, int hlen, 407 int lse_index, bool *entropy_label) 408 { 409 struct mpls_label *hdr, _hdr; 410 u32 entry, label, bos; 411 412 if (!dissector_uses_key(flow_dissector, 413 FLOW_DISSECTOR_KEY_MPLS_ENTROPY) && 414 !dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS)) 415 return FLOW_DISSECT_RET_OUT_GOOD; 416 417 if (lse_index >= FLOW_DIS_MPLS_MAX) 418 return FLOW_DISSECT_RET_OUT_GOOD; 419 420 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, 421 hlen, &_hdr); 422 if (!hdr) 423 return FLOW_DISSECT_RET_OUT_BAD; 424 425 entry = ntohl(hdr->entry); 426 label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT; 427 bos = (entry & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT; 428 429 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS)) { 430 struct flow_dissector_key_mpls *key_mpls; 431 struct flow_dissector_mpls_lse *lse; 432 433 key_mpls = skb_flow_dissector_target(flow_dissector, 434 FLOW_DISSECTOR_KEY_MPLS, 435 target_container); 436 lse = &key_mpls->ls[lse_index]; 437 438 lse->mpls_ttl = (entry & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT; 439 lse->mpls_bos = bos; 440 lse->mpls_tc = (entry & MPLS_LS_TC_MASK) >> MPLS_LS_TC_SHIFT; 441 lse->mpls_label = label; 442 dissector_set_mpls_lse(key_mpls, lse_index); 443 } 444 445 if (*entropy_label && 446 dissector_uses_key(flow_dissector, 447 FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) { 448 struct flow_dissector_key_keyid *key_keyid; 449 450 key_keyid = skb_flow_dissector_target(flow_dissector, 451 FLOW_DISSECTOR_KEY_MPLS_ENTROPY, 452 target_container); 453 key_keyid->keyid = cpu_to_be32(label); 454 } 455 456 *entropy_label = label == MPLS_LABEL_ENTROPY; 457 458 return bos ? FLOW_DISSECT_RET_OUT_GOOD : FLOW_DISSECT_RET_PROTO_AGAIN; 459 } 460 461 static enum flow_dissect_ret 462 __skb_flow_dissect_arp(const struct sk_buff *skb, 463 struct flow_dissector *flow_dissector, 464 void *target_container, void *data, int nhoff, int hlen) 465 { 466 struct flow_dissector_key_arp *key_arp; 467 struct { 468 unsigned char ar_sha[ETH_ALEN]; 469 unsigned char ar_sip[4]; 470 unsigned char ar_tha[ETH_ALEN]; 471 unsigned char ar_tip[4]; 472 } *arp_eth, _arp_eth; 473 const struct arphdr *arp; 474 struct arphdr _arp; 475 476 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ARP)) 477 return FLOW_DISSECT_RET_OUT_GOOD; 478 479 arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data, 480 hlen, &_arp); 481 if (!arp) 482 return FLOW_DISSECT_RET_OUT_BAD; 483 484 if (arp->ar_hrd != htons(ARPHRD_ETHER) || 485 arp->ar_pro != htons(ETH_P_IP) || 486 arp->ar_hln != ETH_ALEN || 487 arp->ar_pln != 4 || 488 (arp->ar_op != htons(ARPOP_REPLY) && 489 arp->ar_op != htons(ARPOP_REQUEST))) 490 return FLOW_DISSECT_RET_OUT_BAD; 491 492 arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp), 493 sizeof(_arp_eth), data, 494 hlen, &_arp_eth); 495 if (!arp_eth) 496 return FLOW_DISSECT_RET_OUT_BAD; 497 498 key_arp = skb_flow_dissector_target(flow_dissector, 499 FLOW_DISSECTOR_KEY_ARP, 500 target_container); 501 502 memcpy(&key_arp->sip, arp_eth->ar_sip, sizeof(key_arp->sip)); 503 memcpy(&key_arp->tip, arp_eth->ar_tip, sizeof(key_arp->tip)); 504 505 /* Only store the lower byte of the opcode; 506 * this covers ARPOP_REPLY and ARPOP_REQUEST. 507 */ 508 key_arp->op = ntohs(arp->ar_op) & 0xff; 509 510 ether_addr_copy(key_arp->sha, arp_eth->ar_sha); 511 ether_addr_copy(key_arp->tha, arp_eth->ar_tha); 512 513 return FLOW_DISSECT_RET_OUT_GOOD; 514 } 515 516 static enum flow_dissect_ret 517 __skb_flow_dissect_gre(const struct sk_buff *skb, 518 struct flow_dissector_key_control *key_control, 519 struct flow_dissector *flow_dissector, 520 void *target_container, void *data, 521 __be16 *p_proto, int *p_nhoff, int *p_hlen, 522 unsigned int flags) 523 { 524 struct flow_dissector_key_keyid *key_keyid; 525 struct gre_base_hdr *hdr, _hdr; 526 int offset = 0; 527 u16 gre_ver; 528 529 hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), 530 data, *p_hlen, &_hdr); 531 if (!hdr) 532 return FLOW_DISSECT_RET_OUT_BAD; 533 534 /* Only look inside GRE without routing */ 535 if (hdr->flags & GRE_ROUTING) 536 return FLOW_DISSECT_RET_OUT_GOOD; 537 538 /* Only look inside GRE for version 0 and 1 */ 539 gre_ver = ntohs(hdr->flags & GRE_VERSION); 540 if (gre_ver > 1) 541 return FLOW_DISSECT_RET_OUT_GOOD; 542 543 *p_proto = hdr->protocol; 544 if (gre_ver) { 545 /* Version1 must be PPTP, and check the flags */ 546 if (!(*p_proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY))) 547 return FLOW_DISSECT_RET_OUT_GOOD; 548 } 549 550 offset += sizeof(struct gre_base_hdr); 551 552 if (hdr->flags & GRE_CSUM) 553 offset += sizeof_field(struct gre_full_hdr, csum) + 554 sizeof_field(struct gre_full_hdr, reserved1); 555 556 if (hdr->flags & GRE_KEY) { 557 const __be32 *keyid; 558 __be32 _keyid; 559 560 keyid = __skb_header_pointer(skb, *p_nhoff + offset, 561 sizeof(_keyid), 562 data, *p_hlen, &_keyid); 563 if (!keyid) 564 return FLOW_DISSECT_RET_OUT_BAD; 565 566 if (dissector_uses_key(flow_dissector, 567 FLOW_DISSECTOR_KEY_GRE_KEYID)) { 568 key_keyid = skb_flow_dissector_target(flow_dissector, 569 FLOW_DISSECTOR_KEY_GRE_KEYID, 570 target_container); 571 if (gre_ver == 0) 572 key_keyid->keyid = *keyid; 573 else 574 key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK; 575 } 576 offset += sizeof_field(struct gre_full_hdr, key); 577 } 578 579 if (hdr->flags & GRE_SEQ) 580 offset += sizeof_field(struct pptp_gre_header, seq); 581 582 if (gre_ver == 0) { 583 if (*p_proto == htons(ETH_P_TEB)) { 584 const struct ethhdr *eth; 585 struct ethhdr _eth; 586 587 eth = __skb_header_pointer(skb, *p_nhoff + offset, 588 sizeof(_eth), 589 data, *p_hlen, &_eth); 590 if (!eth) 591 return FLOW_DISSECT_RET_OUT_BAD; 592 *p_proto = eth->h_proto; 593 offset += sizeof(*eth); 594 595 /* Cap headers that we access via pointers at the 596 * end of the Ethernet header as our maximum alignment 597 * at that point is only 2 bytes. 598 */ 599 if (NET_IP_ALIGN) 600 *p_hlen = *p_nhoff + offset; 601 } 602 } else { /* version 1, must be PPTP */ 603 u8 _ppp_hdr[PPP_HDRLEN]; 604 u8 *ppp_hdr; 605 606 if (hdr->flags & GRE_ACK) 607 offset += sizeof_field(struct pptp_gre_header, ack); 608 609 ppp_hdr = __skb_header_pointer(skb, *p_nhoff + offset, 610 sizeof(_ppp_hdr), 611 data, *p_hlen, _ppp_hdr); 612 if (!ppp_hdr) 613 return FLOW_DISSECT_RET_OUT_BAD; 614 615 switch (PPP_PROTOCOL(ppp_hdr)) { 616 case PPP_IP: 617 *p_proto = htons(ETH_P_IP); 618 break; 619 case PPP_IPV6: 620 *p_proto = htons(ETH_P_IPV6); 621 break; 622 default: 623 /* Could probably catch some more like MPLS */ 624 break; 625 } 626 627 offset += PPP_HDRLEN; 628 } 629 630 *p_nhoff += offset; 631 key_control->flags |= FLOW_DIS_ENCAPSULATION; 632 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 633 return FLOW_DISSECT_RET_OUT_GOOD; 634 635 return FLOW_DISSECT_RET_PROTO_AGAIN; 636 } 637 638 /** 639 * __skb_flow_dissect_batadv() - dissect batman-adv header 640 * @skb: sk_buff to with the batman-adv header 641 * @key_control: flow dissectors control key 642 * @data: raw buffer pointer to the packet, if NULL use skb->data 643 * @p_proto: pointer used to update the protocol to process next 644 * @p_nhoff: pointer used to update inner network header offset 645 * @hlen: packet header length 646 * @flags: any combination of FLOW_DISSECTOR_F_* 647 * 648 * ETH_P_BATMAN packets are tried to be dissected. Only 649 * &struct batadv_unicast packets are actually processed because they contain an 650 * inner ethernet header and are usually followed by actual network header. This 651 * allows the flow dissector to continue processing the packet. 652 * 653 * Return: FLOW_DISSECT_RET_PROTO_AGAIN when &struct batadv_unicast was found, 654 * FLOW_DISSECT_RET_OUT_GOOD when dissector should stop after encapsulation, 655 * otherwise FLOW_DISSECT_RET_OUT_BAD 656 */ 657 static enum flow_dissect_ret 658 __skb_flow_dissect_batadv(const struct sk_buff *skb, 659 struct flow_dissector_key_control *key_control, 660 void *data, __be16 *p_proto, int *p_nhoff, int hlen, 661 unsigned int flags) 662 { 663 struct { 664 struct batadv_unicast_packet batadv_unicast; 665 struct ethhdr eth; 666 } *hdr, _hdr; 667 668 hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), data, hlen, 669 &_hdr); 670 if (!hdr) 671 return FLOW_DISSECT_RET_OUT_BAD; 672 673 if (hdr->batadv_unicast.version != BATADV_COMPAT_VERSION) 674 return FLOW_DISSECT_RET_OUT_BAD; 675 676 if (hdr->batadv_unicast.packet_type != BATADV_UNICAST) 677 return FLOW_DISSECT_RET_OUT_BAD; 678 679 *p_proto = hdr->eth.h_proto; 680 *p_nhoff += sizeof(*hdr); 681 682 key_control->flags |= FLOW_DIS_ENCAPSULATION; 683 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 684 return FLOW_DISSECT_RET_OUT_GOOD; 685 686 return FLOW_DISSECT_RET_PROTO_AGAIN; 687 } 688 689 static void 690 __skb_flow_dissect_tcp(const struct sk_buff *skb, 691 struct flow_dissector *flow_dissector, 692 void *target_container, void *data, int thoff, int hlen) 693 { 694 struct flow_dissector_key_tcp *key_tcp; 695 struct tcphdr *th, _th; 696 697 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_TCP)) 698 return; 699 700 th = __skb_header_pointer(skb, thoff, sizeof(_th), data, hlen, &_th); 701 if (!th) 702 return; 703 704 if (unlikely(__tcp_hdrlen(th) < sizeof(_th))) 705 return; 706 707 key_tcp = skb_flow_dissector_target(flow_dissector, 708 FLOW_DISSECTOR_KEY_TCP, 709 target_container); 710 key_tcp->flags = (*(__be16 *) &tcp_flag_word(th) & htons(0x0FFF)); 711 } 712 713 static void 714 __skb_flow_dissect_ports(const struct sk_buff *skb, 715 struct flow_dissector *flow_dissector, 716 void *target_container, void *data, int nhoff, 717 u8 ip_proto, int hlen) 718 { 719 enum flow_dissector_key_id dissector_ports = FLOW_DISSECTOR_KEY_MAX; 720 struct flow_dissector_key_ports *key_ports; 721 722 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS)) 723 dissector_ports = FLOW_DISSECTOR_KEY_PORTS; 724 else if (dissector_uses_key(flow_dissector, 725 FLOW_DISSECTOR_KEY_PORTS_RANGE)) 726 dissector_ports = FLOW_DISSECTOR_KEY_PORTS_RANGE; 727 728 if (dissector_ports == FLOW_DISSECTOR_KEY_MAX) 729 return; 730 731 key_ports = skb_flow_dissector_target(flow_dissector, 732 dissector_ports, 733 target_container); 734 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto, 735 data, hlen); 736 } 737 738 static void 739 __skb_flow_dissect_ipv4(const struct sk_buff *skb, 740 struct flow_dissector *flow_dissector, 741 void *target_container, void *data, const struct iphdr *iph) 742 { 743 struct flow_dissector_key_ip *key_ip; 744 745 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP)) 746 return; 747 748 key_ip = skb_flow_dissector_target(flow_dissector, 749 FLOW_DISSECTOR_KEY_IP, 750 target_container); 751 key_ip->tos = iph->tos; 752 key_ip->ttl = iph->ttl; 753 } 754 755 static void 756 __skb_flow_dissect_ipv6(const struct sk_buff *skb, 757 struct flow_dissector *flow_dissector, 758 void *target_container, void *data, const struct ipv6hdr *iph) 759 { 760 struct flow_dissector_key_ip *key_ip; 761 762 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP)) 763 return; 764 765 key_ip = skb_flow_dissector_target(flow_dissector, 766 FLOW_DISSECTOR_KEY_IP, 767 target_container); 768 key_ip->tos = ipv6_get_dsfield(iph); 769 key_ip->ttl = iph->hop_limit; 770 } 771 772 /* Maximum number of protocol headers that can be parsed in 773 * __skb_flow_dissect 774 */ 775 #define MAX_FLOW_DISSECT_HDRS 15 776 777 static bool skb_flow_dissect_allowed(int *num_hdrs) 778 { 779 ++*num_hdrs; 780 781 return (*num_hdrs <= MAX_FLOW_DISSECT_HDRS); 782 } 783 784 static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys, 785 struct flow_dissector *flow_dissector, 786 void *target_container) 787 { 788 struct flow_dissector_key_ports *key_ports = NULL; 789 struct flow_dissector_key_control *key_control; 790 struct flow_dissector_key_basic *key_basic; 791 struct flow_dissector_key_addrs *key_addrs; 792 struct flow_dissector_key_tags *key_tags; 793 794 key_control = skb_flow_dissector_target(flow_dissector, 795 FLOW_DISSECTOR_KEY_CONTROL, 796 target_container); 797 key_control->thoff = flow_keys->thoff; 798 if (flow_keys->is_frag) 799 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 800 if (flow_keys->is_first_frag) 801 key_control->flags |= FLOW_DIS_FIRST_FRAG; 802 if (flow_keys->is_encap) 803 key_control->flags |= FLOW_DIS_ENCAPSULATION; 804 805 key_basic = skb_flow_dissector_target(flow_dissector, 806 FLOW_DISSECTOR_KEY_BASIC, 807 target_container); 808 key_basic->n_proto = flow_keys->n_proto; 809 key_basic->ip_proto = flow_keys->ip_proto; 810 811 if (flow_keys->addr_proto == ETH_P_IP && 812 dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IPV4_ADDRS)) { 813 key_addrs = skb_flow_dissector_target(flow_dissector, 814 FLOW_DISSECTOR_KEY_IPV4_ADDRS, 815 target_container); 816 key_addrs->v4addrs.src = flow_keys->ipv4_src; 817 key_addrs->v4addrs.dst = flow_keys->ipv4_dst; 818 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 819 } else if (flow_keys->addr_proto == ETH_P_IPV6 && 820 dissector_uses_key(flow_dissector, 821 FLOW_DISSECTOR_KEY_IPV6_ADDRS)) { 822 key_addrs = skb_flow_dissector_target(flow_dissector, 823 FLOW_DISSECTOR_KEY_IPV6_ADDRS, 824 target_container); 825 memcpy(&key_addrs->v6addrs, &flow_keys->ipv6_src, 826 sizeof(key_addrs->v6addrs)); 827 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 828 } 829 830 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS)) 831 key_ports = skb_flow_dissector_target(flow_dissector, 832 FLOW_DISSECTOR_KEY_PORTS, 833 target_container); 834 else if (dissector_uses_key(flow_dissector, 835 FLOW_DISSECTOR_KEY_PORTS_RANGE)) 836 key_ports = skb_flow_dissector_target(flow_dissector, 837 FLOW_DISSECTOR_KEY_PORTS_RANGE, 838 target_container); 839 840 if (key_ports) { 841 key_ports->src = flow_keys->sport; 842 key_ports->dst = flow_keys->dport; 843 } 844 845 if (dissector_uses_key(flow_dissector, 846 FLOW_DISSECTOR_KEY_FLOW_LABEL)) { 847 key_tags = skb_flow_dissector_target(flow_dissector, 848 FLOW_DISSECTOR_KEY_FLOW_LABEL, 849 target_container); 850 key_tags->flow_label = ntohl(flow_keys->flow_label); 851 } 852 } 853 854 bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx, 855 __be16 proto, int nhoff, int hlen, unsigned int flags) 856 { 857 struct bpf_flow_keys *flow_keys = ctx->flow_keys; 858 u32 result; 859 860 /* Pass parameters to the BPF program */ 861 memset(flow_keys, 0, sizeof(*flow_keys)); 862 flow_keys->n_proto = proto; 863 flow_keys->nhoff = nhoff; 864 flow_keys->thoff = flow_keys->nhoff; 865 866 BUILD_BUG_ON((int)BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG != 867 (int)FLOW_DISSECTOR_F_PARSE_1ST_FRAG); 868 BUILD_BUG_ON((int)BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL != 869 (int)FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 870 BUILD_BUG_ON((int)BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP != 871 (int)FLOW_DISSECTOR_F_STOP_AT_ENCAP); 872 flow_keys->flags = flags; 873 874 result = bpf_prog_run_pin_on_cpu(prog, ctx); 875 876 flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, nhoff, hlen); 877 flow_keys->thoff = clamp_t(u16, flow_keys->thoff, 878 flow_keys->nhoff, hlen); 879 880 return result == BPF_OK; 881 } 882 883 /** 884 * __skb_flow_dissect - extract the flow_keys struct and return it 885 * @net: associated network namespace, derived from @skb if NULL 886 * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified 887 * @flow_dissector: list of keys to dissect 888 * @target_container: target structure to put dissected values into 889 * @data: raw buffer pointer to the packet, if NULL use skb->data 890 * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol 891 * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb) 892 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 893 * @flags: flags that control the dissection process, e.g. 894 * FLOW_DISSECTOR_F_STOP_AT_ENCAP. 895 * 896 * The function will try to retrieve individual keys into target specified 897 * by flow_dissector from either the skbuff or a raw buffer specified by the 898 * rest parameters. 899 * 900 * Caller must take care of zeroing target container memory. 901 */ 902 bool __skb_flow_dissect(const struct net *net, 903 const struct sk_buff *skb, 904 struct flow_dissector *flow_dissector, 905 void *target_container, 906 void *data, __be16 proto, int nhoff, int hlen, 907 unsigned int flags) 908 { 909 struct flow_dissector_key_control *key_control; 910 struct flow_dissector_key_basic *key_basic; 911 struct flow_dissector_key_addrs *key_addrs; 912 struct flow_dissector_key_tags *key_tags; 913 struct flow_dissector_key_vlan *key_vlan; 914 enum flow_dissect_ret fdret; 915 enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX; 916 bool mpls_el = false; 917 int mpls_lse = 0; 918 int num_hdrs = 0; 919 u8 ip_proto = 0; 920 bool ret; 921 922 if (!data) { 923 data = skb->data; 924 proto = skb_vlan_tag_present(skb) ? 925 skb->vlan_proto : skb->protocol; 926 nhoff = skb_network_offset(skb); 927 hlen = skb_headlen(skb); 928 #if IS_ENABLED(CONFIG_NET_DSA) 929 if (unlikely(skb->dev && netdev_uses_dsa(skb->dev) && 930 proto == htons(ETH_P_XDSA))) { 931 const struct dsa_device_ops *ops; 932 int offset = 0; 933 934 ops = skb->dev->dsa_ptr->tag_ops; 935 /* Tail taggers don't break flow dissection */ 936 if (!ops->tail_tag) { 937 if (ops->flow_dissect) 938 ops->flow_dissect(skb, &proto, &offset); 939 else 940 dsa_tag_generic_flow_dissect(skb, 941 &proto, 942 &offset); 943 hlen -= offset; 944 nhoff += offset; 945 } 946 } 947 #endif 948 } 949 950 /* It is ensured by skb_flow_dissector_init() that control key will 951 * be always present. 952 */ 953 key_control = skb_flow_dissector_target(flow_dissector, 954 FLOW_DISSECTOR_KEY_CONTROL, 955 target_container); 956 957 /* It is ensured by skb_flow_dissector_init() that basic key will 958 * be always present. 959 */ 960 key_basic = skb_flow_dissector_target(flow_dissector, 961 FLOW_DISSECTOR_KEY_BASIC, 962 target_container); 963 964 if (skb) { 965 if (!net) { 966 if (skb->dev) 967 net = dev_net(skb->dev); 968 else if (skb->sk) 969 net = sock_net(skb->sk); 970 } 971 } 972 973 WARN_ON_ONCE(!net); 974 if (net) { 975 enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR; 976 struct bpf_prog_array *run_array; 977 978 rcu_read_lock(); 979 run_array = rcu_dereference(init_net.bpf.run_array[type]); 980 if (!run_array) 981 run_array = rcu_dereference(net->bpf.run_array[type]); 982 983 if (run_array) { 984 struct bpf_flow_keys flow_keys; 985 struct bpf_flow_dissector ctx = { 986 .flow_keys = &flow_keys, 987 .data = data, 988 .data_end = data + hlen, 989 }; 990 __be16 n_proto = proto; 991 struct bpf_prog *prog; 992 993 if (skb) { 994 ctx.skb = skb; 995 /* we can't use 'proto' in the skb case 996 * because it might be set to skb->vlan_proto 997 * which has been pulled from the data 998 */ 999 n_proto = skb->protocol; 1000 } 1001 1002 prog = READ_ONCE(run_array->items[0].prog); 1003 ret = bpf_flow_dissect(prog, &ctx, n_proto, nhoff, 1004 hlen, flags); 1005 __skb_flow_bpf_to_target(&flow_keys, flow_dissector, 1006 target_container); 1007 rcu_read_unlock(); 1008 return ret; 1009 } 1010 rcu_read_unlock(); 1011 } 1012 1013 if (dissector_uses_key(flow_dissector, 1014 FLOW_DISSECTOR_KEY_ETH_ADDRS)) { 1015 struct ethhdr *eth = eth_hdr(skb); 1016 struct flow_dissector_key_eth_addrs *key_eth_addrs; 1017 1018 key_eth_addrs = skb_flow_dissector_target(flow_dissector, 1019 FLOW_DISSECTOR_KEY_ETH_ADDRS, 1020 target_container); 1021 memcpy(key_eth_addrs, ð->h_dest, sizeof(*key_eth_addrs)); 1022 } 1023 1024 proto_again: 1025 fdret = FLOW_DISSECT_RET_CONTINUE; 1026 1027 switch (proto) { 1028 case htons(ETH_P_IP): { 1029 const struct iphdr *iph; 1030 struct iphdr _iph; 1031 1032 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 1033 if (!iph || iph->ihl < 5) { 1034 fdret = FLOW_DISSECT_RET_OUT_BAD; 1035 break; 1036 } 1037 1038 nhoff += iph->ihl * 4; 1039 1040 ip_proto = iph->protocol; 1041 1042 if (dissector_uses_key(flow_dissector, 1043 FLOW_DISSECTOR_KEY_IPV4_ADDRS)) { 1044 key_addrs = skb_flow_dissector_target(flow_dissector, 1045 FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1046 target_container); 1047 1048 memcpy(&key_addrs->v4addrs, &iph->saddr, 1049 sizeof(key_addrs->v4addrs)); 1050 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 1051 } 1052 1053 if (ip_is_fragment(iph)) { 1054 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 1055 1056 if (iph->frag_off & htons(IP_OFFSET)) { 1057 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1058 break; 1059 } else { 1060 key_control->flags |= FLOW_DIS_FIRST_FRAG; 1061 if (!(flags & 1062 FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) { 1063 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1064 break; 1065 } 1066 } 1067 } 1068 1069 __skb_flow_dissect_ipv4(skb, flow_dissector, 1070 target_container, data, iph); 1071 1072 break; 1073 } 1074 case htons(ETH_P_IPV6): { 1075 const struct ipv6hdr *iph; 1076 struct ipv6hdr _iph; 1077 1078 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 1079 if (!iph) { 1080 fdret = FLOW_DISSECT_RET_OUT_BAD; 1081 break; 1082 } 1083 1084 ip_proto = iph->nexthdr; 1085 nhoff += sizeof(struct ipv6hdr); 1086 1087 if (dissector_uses_key(flow_dissector, 1088 FLOW_DISSECTOR_KEY_IPV6_ADDRS)) { 1089 key_addrs = skb_flow_dissector_target(flow_dissector, 1090 FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1091 target_container); 1092 1093 memcpy(&key_addrs->v6addrs, &iph->saddr, 1094 sizeof(key_addrs->v6addrs)); 1095 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1096 } 1097 1098 if ((dissector_uses_key(flow_dissector, 1099 FLOW_DISSECTOR_KEY_FLOW_LABEL) || 1100 (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) && 1101 ip6_flowlabel(iph)) { 1102 __be32 flow_label = ip6_flowlabel(iph); 1103 1104 if (dissector_uses_key(flow_dissector, 1105 FLOW_DISSECTOR_KEY_FLOW_LABEL)) { 1106 key_tags = skb_flow_dissector_target(flow_dissector, 1107 FLOW_DISSECTOR_KEY_FLOW_LABEL, 1108 target_container); 1109 key_tags->flow_label = ntohl(flow_label); 1110 } 1111 if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) { 1112 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1113 break; 1114 } 1115 } 1116 1117 __skb_flow_dissect_ipv6(skb, flow_dissector, 1118 target_container, data, iph); 1119 1120 break; 1121 } 1122 case htons(ETH_P_8021AD): 1123 case htons(ETH_P_8021Q): { 1124 const struct vlan_hdr *vlan = NULL; 1125 struct vlan_hdr _vlan; 1126 __be16 saved_vlan_tpid = proto; 1127 1128 if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX && 1129 skb && skb_vlan_tag_present(skb)) { 1130 proto = skb->protocol; 1131 } else { 1132 vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), 1133 data, hlen, &_vlan); 1134 if (!vlan) { 1135 fdret = FLOW_DISSECT_RET_OUT_BAD; 1136 break; 1137 } 1138 1139 proto = vlan->h_vlan_encapsulated_proto; 1140 nhoff += sizeof(*vlan); 1141 } 1142 1143 if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX) { 1144 dissector_vlan = FLOW_DISSECTOR_KEY_VLAN; 1145 } else if (dissector_vlan == FLOW_DISSECTOR_KEY_VLAN) { 1146 dissector_vlan = FLOW_DISSECTOR_KEY_CVLAN; 1147 } else { 1148 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1149 break; 1150 } 1151 1152 if (dissector_uses_key(flow_dissector, dissector_vlan)) { 1153 key_vlan = skb_flow_dissector_target(flow_dissector, 1154 dissector_vlan, 1155 target_container); 1156 1157 if (!vlan) { 1158 key_vlan->vlan_id = skb_vlan_tag_get_id(skb); 1159 key_vlan->vlan_priority = skb_vlan_tag_get_prio(skb); 1160 } else { 1161 key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) & 1162 VLAN_VID_MASK; 1163 key_vlan->vlan_priority = 1164 (ntohs(vlan->h_vlan_TCI) & 1165 VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; 1166 } 1167 key_vlan->vlan_tpid = saved_vlan_tpid; 1168 } 1169 1170 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1171 break; 1172 } 1173 case htons(ETH_P_PPP_SES): { 1174 struct { 1175 struct pppoe_hdr hdr; 1176 __be16 proto; 1177 } *hdr, _hdr; 1178 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 1179 if (!hdr) { 1180 fdret = FLOW_DISSECT_RET_OUT_BAD; 1181 break; 1182 } 1183 1184 proto = hdr->proto; 1185 nhoff += PPPOE_SES_HLEN; 1186 switch (proto) { 1187 case htons(PPP_IP): 1188 proto = htons(ETH_P_IP); 1189 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1190 break; 1191 case htons(PPP_IPV6): 1192 proto = htons(ETH_P_IPV6); 1193 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1194 break; 1195 default: 1196 fdret = FLOW_DISSECT_RET_OUT_BAD; 1197 break; 1198 } 1199 break; 1200 } 1201 case htons(ETH_P_TIPC): { 1202 struct tipc_basic_hdr *hdr, _hdr; 1203 1204 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), 1205 data, hlen, &_hdr); 1206 if (!hdr) { 1207 fdret = FLOW_DISSECT_RET_OUT_BAD; 1208 break; 1209 } 1210 1211 if (dissector_uses_key(flow_dissector, 1212 FLOW_DISSECTOR_KEY_TIPC)) { 1213 key_addrs = skb_flow_dissector_target(flow_dissector, 1214 FLOW_DISSECTOR_KEY_TIPC, 1215 target_container); 1216 key_addrs->tipckey.key = tipc_hdr_rps_key(hdr); 1217 key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC; 1218 } 1219 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1220 break; 1221 } 1222 1223 case htons(ETH_P_MPLS_UC): 1224 case htons(ETH_P_MPLS_MC): 1225 fdret = __skb_flow_dissect_mpls(skb, flow_dissector, 1226 target_container, data, 1227 nhoff, hlen, mpls_lse, 1228 &mpls_el); 1229 nhoff += sizeof(struct mpls_label); 1230 mpls_lse++; 1231 break; 1232 case htons(ETH_P_FCOE): 1233 if ((hlen - nhoff) < FCOE_HEADER_LEN) { 1234 fdret = FLOW_DISSECT_RET_OUT_BAD; 1235 break; 1236 } 1237 1238 nhoff += FCOE_HEADER_LEN; 1239 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1240 break; 1241 1242 case htons(ETH_P_ARP): 1243 case htons(ETH_P_RARP): 1244 fdret = __skb_flow_dissect_arp(skb, flow_dissector, 1245 target_container, data, 1246 nhoff, hlen); 1247 break; 1248 1249 case htons(ETH_P_BATMAN): 1250 fdret = __skb_flow_dissect_batadv(skb, key_control, data, 1251 &proto, &nhoff, hlen, flags); 1252 break; 1253 1254 default: 1255 fdret = FLOW_DISSECT_RET_OUT_BAD; 1256 break; 1257 } 1258 1259 /* Process result of proto processing */ 1260 switch (fdret) { 1261 case FLOW_DISSECT_RET_OUT_GOOD: 1262 goto out_good; 1263 case FLOW_DISSECT_RET_PROTO_AGAIN: 1264 if (skb_flow_dissect_allowed(&num_hdrs)) 1265 goto proto_again; 1266 goto out_good; 1267 case FLOW_DISSECT_RET_CONTINUE: 1268 case FLOW_DISSECT_RET_IPPROTO_AGAIN: 1269 break; 1270 case FLOW_DISSECT_RET_OUT_BAD: 1271 default: 1272 goto out_bad; 1273 } 1274 1275 ip_proto_again: 1276 fdret = FLOW_DISSECT_RET_CONTINUE; 1277 1278 switch (ip_proto) { 1279 case IPPROTO_GRE: 1280 fdret = __skb_flow_dissect_gre(skb, key_control, flow_dissector, 1281 target_container, data, 1282 &proto, &nhoff, &hlen, flags); 1283 break; 1284 1285 case NEXTHDR_HOP: 1286 case NEXTHDR_ROUTING: 1287 case NEXTHDR_DEST: { 1288 u8 _opthdr[2], *opthdr; 1289 1290 if (proto != htons(ETH_P_IPV6)) 1291 break; 1292 1293 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr), 1294 data, hlen, &_opthdr); 1295 if (!opthdr) { 1296 fdret = FLOW_DISSECT_RET_OUT_BAD; 1297 break; 1298 } 1299 1300 ip_proto = opthdr[0]; 1301 nhoff += (opthdr[1] + 1) << 3; 1302 1303 fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN; 1304 break; 1305 } 1306 case NEXTHDR_FRAGMENT: { 1307 struct frag_hdr _fh, *fh; 1308 1309 if (proto != htons(ETH_P_IPV6)) 1310 break; 1311 1312 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh), 1313 data, hlen, &_fh); 1314 1315 if (!fh) { 1316 fdret = FLOW_DISSECT_RET_OUT_BAD; 1317 break; 1318 } 1319 1320 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 1321 1322 nhoff += sizeof(_fh); 1323 ip_proto = fh->nexthdr; 1324 1325 if (!(fh->frag_off & htons(IP6_OFFSET))) { 1326 key_control->flags |= FLOW_DIS_FIRST_FRAG; 1327 if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) { 1328 fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN; 1329 break; 1330 } 1331 } 1332 1333 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1334 break; 1335 } 1336 case IPPROTO_IPIP: 1337 proto = htons(ETH_P_IP); 1338 1339 key_control->flags |= FLOW_DIS_ENCAPSULATION; 1340 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) { 1341 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1342 break; 1343 } 1344 1345 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1346 break; 1347 1348 case IPPROTO_IPV6: 1349 proto = htons(ETH_P_IPV6); 1350 1351 key_control->flags |= FLOW_DIS_ENCAPSULATION; 1352 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) { 1353 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1354 break; 1355 } 1356 1357 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1358 break; 1359 1360 1361 case IPPROTO_MPLS: 1362 proto = htons(ETH_P_MPLS_UC); 1363 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1364 break; 1365 1366 case IPPROTO_TCP: 1367 __skb_flow_dissect_tcp(skb, flow_dissector, target_container, 1368 data, nhoff, hlen); 1369 break; 1370 1371 case IPPROTO_ICMP: 1372 case IPPROTO_ICMPV6: 1373 __skb_flow_dissect_icmp(skb, flow_dissector, target_container, 1374 data, nhoff, hlen); 1375 break; 1376 1377 default: 1378 break; 1379 } 1380 1381 if (!(key_control->flags & FLOW_DIS_IS_FRAGMENT)) 1382 __skb_flow_dissect_ports(skb, flow_dissector, target_container, 1383 data, nhoff, ip_proto, hlen); 1384 1385 /* Process result of IP proto processing */ 1386 switch (fdret) { 1387 case FLOW_DISSECT_RET_PROTO_AGAIN: 1388 if (skb_flow_dissect_allowed(&num_hdrs)) 1389 goto proto_again; 1390 break; 1391 case FLOW_DISSECT_RET_IPPROTO_AGAIN: 1392 if (skb_flow_dissect_allowed(&num_hdrs)) 1393 goto ip_proto_again; 1394 break; 1395 case FLOW_DISSECT_RET_OUT_GOOD: 1396 case FLOW_DISSECT_RET_CONTINUE: 1397 break; 1398 case FLOW_DISSECT_RET_OUT_BAD: 1399 default: 1400 goto out_bad; 1401 } 1402 1403 out_good: 1404 ret = true; 1405 1406 out: 1407 key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen); 1408 key_basic->n_proto = proto; 1409 key_basic->ip_proto = ip_proto; 1410 1411 return ret; 1412 1413 out_bad: 1414 ret = false; 1415 goto out; 1416 } 1417 EXPORT_SYMBOL(__skb_flow_dissect); 1418 1419 static siphash_key_t hashrnd __read_mostly; 1420 static __always_inline void __flow_hash_secret_init(void) 1421 { 1422 net_get_random_once(&hashrnd, sizeof(hashrnd)); 1423 } 1424 1425 static const void *flow_keys_hash_start(const struct flow_keys *flow) 1426 { 1427 BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % SIPHASH_ALIGNMENT); 1428 return &flow->FLOW_KEYS_HASH_START_FIELD; 1429 } 1430 1431 static inline size_t flow_keys_hash_length(const struct flow_keys *flow) 1432 { 1433 size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs); 1434 1435 BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32)); 1436 1437 switch (flow->control.addr_type) { 1438 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1439 diff -= sizeof(flow->addrs.v4addrs); 1440 break; 1441 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1442 diff -= sizeof(flow->addrs.v6addrs); 1443 break; 1444 case FLOW_DISSECTOR_KEY_TIPC: 1445 diff -= sizeof(flow->addrs.tipckey); 1446 break; 1447 } 1448 return sizeof(*flow) - diff; 1449 } 1450 1451 __be32 flow_get_u32_src(const struct flow_keys *flow) 1452 { 1453 switch (flow->control.addr_type) { 1454 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1455 return flow->addrs.v4addrs.src; 1456 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1457 return (__force __be32)ipv6_addr_hash( 1458 &flow->addrs.v6addrs.src); 1459 case FLOW_DISSECTOR_KEY_TIPC: 1460 return flow->addrs.tipckey.key; 1461 default: 1462 return 0; 1463 } 1464 } 1465 EXPORT_SYMBOL(flow_get_u32_src); 1466 1467 __be32 flow_get_u32_dst(const struct flow_keys *flow) 1468 { 1469 switch (flow->control.addr_type) { 1470 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1471 return flow->addrs.v4addrs.dst; 1472 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1473 return (__force __be32)ipv6_addr_hash( 1474 &flow->addrs.v6addrs.dst); 1475 default: 1476 return 0; 1477 } 1478 } 1479 EXPORT_SYMBOL(flow_get_u32_dst); 1480 1481 /* Sort the source and destination IP (and the ports if the IP are the same), 1482 * to have consistent hash within the two directions 1483 */ 1484 static inline void __flow_hash_consistentify(struct flow_keys *keys) 1485 { 1486 int addr_diff, i; 1487 1488 switch (keys->control.addr_type) { 1489 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1490 addr_diff = (__force u32)keys->addrs.v4addrs.dst - 1491 (__force u32)keys->addrs.v4addrs.src; 1492 if ((addr_diff < 0) || 1493 (addr_diff == 0 && 1494 ((__force u16)keys->ports.dst < 1495 (__force u16)keys->ports.src))) { 1496 swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst); 1497 swap(keys->ports.src, keys->ports.dst); 1498 } 1499 break; 1500 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1501 addr_diff = memcmp(&keys->addrs.v6addrs.dst, 1502 &keys->addrs.v6addrs.src, 1503 sizeof(keys->addrs.v6addrs.dst)); 1504 if ((addr_diff < 0) || 1505 (addr_diff == 0 && 1506 ((__force u16)keys->ports.dst < 1507 (__force u16)keys->ports.src))) { 1508 for (i = 0; i < 4; i++) 1509 swap(keys->addrs.v6addrs.src.s6_addr32[i], 1510 keys->addrs.v6addrs.dst.s6_addr32[i]); 1511 swap(keys->ports.src, keys->ports.dst); 1512 } 1513 break; 1514 } 1515 } 1516 1517 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, 1518 const siphash_key_t *keyval) 1519 { 1520 u32 hash; 1521 1522 __flow_hash_consistentify(keys); 1523 1524 hash = siphash(flow_keys_hash_start(keys), 1525 flow_keys_hash_length(keys), keyval); 1526 if (!hash) 1527 hash = 1; 1528 1529 return hash; 1530 } 1531 1532 u32 flow_hash_from_keys(struct flow_keys *keys) 1533 { 1534 __flow_hash_secret_init(); 1535 return __flow_hash_from_keys(keys, &hashrnd); 1536 } 1537 EXPORT_SYMBOL(flow_hash_from_keys); 1538 1539 static inline u32 ___skb_get_hash(const struct sk_buff *skb, 1540 struct flow_keys *keys, 1541 const siphash_key_t *keyval) 1542 { 1543 skb_flow_dissect_flow_keys(skb, keys, 1544 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 1545 1546 return __flow_hash_from_keys(keys, keyval); 1547 } 1548 1549 struct _flow_keys_digest_data { 1550 __be16 n_proto; 1551 u8 ip_proto; 1552 u8 padding; 1553 __be32 ports; 1554 __be32 src; 1555 __be32 dst; 1556 }; 1557 1558 void make_flow_keys_digest(struct flow_keys_digest *digest, 1559 const struct flow_keys *flow) 1560 { 1561 struct _flow_keys_digest_data *data = 1562 (struct _flow_keys_digest_data *)digest; 1563 1564 BUILD_BUG_ON(sizeof(*data) > sizeof(*digest)); 1565 1566 memset(digest, 0, sizeof(*digest)); 1567 1568 data->n_proto = flow->basic.n_proto; 1569 data->ip_proto = flow->basic.ip_proto; 1570 data->ports = flow->ports.ports; 1571 data->src = flow->addrs.v4addrs.src; 1572 data->dst = flow->addrs.v4addrs.dst; 1573 } 1574 EXPORT_SYMBOL(make_flow_keys_digest); 1575 1576 static struct flow_dissector flow_keys_dissector_symmetric __read_mostly; 1577 1578 u32 __skb_get_hash_symmetric(const struct sk_buff *skb) 1579 { 1580 struct flow_keys keys; 1581 1582 __flow_hash_secret_init(); 1583 1584 memset(&keys, 0, sizeof(keys)); 1585 __skb_flow_dissect(NULL, skb, &flow_keys_dissector_symmetric, 1586 &keys, NULL, 0, 0, 0, 1587 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 1588 1589 return __flow_hash_from_keys(&keys, &hashrnd); 1590 } 1591 EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric); 1592 1593 /** 1594 * __skb_get_hash: calculate a flow hash 1595 * @skb: sk_buff to calculate flow hash from 1596 * 1597 * This function calculates a flow hash based on src/dst addresses 1598 * and src/dst port numbers. Sets hash in skb to non-zero hash value 1599 * on success, zero indicates no valid hash. Also, sets l4_hash in skb 1600 * if hash is a canonical 4-tuple hash over transport ports. 1601 */ 1602 void __skb_get_hash(struct sk_buff *skb) 1603 { 1604 struct flow_keys keys; 1605 u32 hash; 1606 1607 __flow_hash_secret_init(); 1608 1609 hash = ___skb_get_hash(skb, &keys, &hashrnd); 1610 1611 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys)); 1612 } 1613 EXPORT_SYMBOL(__skb_get_hash); 1614 1615 __u32 skb_get_hash_perturb(const struct sk_buff *skb, 1616 const siphash_key_t *perturb) 1617 { 1618 struct flow_keys keys; 1619 1620 return ___skb_get_hash(skb, &keys, perturb); 1621 } 1622 EXPORT_SYMBOL(skb_get_hash_perturb); 1623 1624 u32 __skb_get_poff(const struct sk_buff *skb, void *data, 1625 const struct flow_keys_basic *keys, int hlen) 1626 { 1627 u32 poff = keys->control.thoff; 1628 1629 /* skip L4 headers for fragments after the first */ 1630 if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) && 1631 !(keys->control.flags & FLOW_DIS_FIRST_FRAG)) 1632 return poff; 1633 1634 switch (keys->basic.ip_proto) { 1635 case IPPROTO_TCP: { 1636 /* access doff as u8 to avoid unaligned access */ 1637 const u8 *doff; 1638 u8 _doff; 1639 1640 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff), 1641 data, hlen, &_doff); 1642 if (!doff) 1643 return poff; 1644 1645 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2); 1646 break; 1647 } 1648 case IPPROTO_UDP: 1649 case IPPROTO_UDPLITE: 1650 poff += sizeof(struct udphdr); 1651 break; 1652 /* For the rest, we do not really care about header 1653 * extensions at this point for now. 1654 */ 1655 case IPPROTO_ICMP: 1656 poff += sizeof(struct icmphdr); 1657 break; 1658 case IPPROTO_ICMPV6: 1659 poff += sizeof(struct icmp6hdr); 1660 break; 1661 case IPPROTO_IGMP: 1662 poff += sizeof(struct igmphdr); 1663 break; 1664 case IPPROTO_DCCP: 1665 poff += sizeof(struct dccp_hdr); 1666 break; 1667 case IPPROTO_SCTP: 1668 poff += sizeof(struct sctphdr); 1669 break; 1670 } 1671 1672 return poff; 1673 } 1674 1675 /** 1676 * skb_get_poff - get the offset to the payload 1677 * @skb: sk_buff to get the payload offset from 1678 * 1679 * The function will get the offset to the payload as far as it could 1680 * be dissected. The main user is currently BPF, so that we can dynamically 1681 * truncate packets without needing to push actual payload to the user 1682 * space and can analyze headers only, instead. 1683 */ 1684 u32 skb_get_poff(const struct sk_buff *skb) 1685 { 1686 struct flow_keys_basic keys; 1687 1688 if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys, 1689 NULL, 0, 0, 0, 0)) 1690 return 0; 1691 1692 return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb)); 1693 } 1694 1695 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys) 1696 { 1697 memset(keys, 0, sizeof(*keys)); 1698 1699 memcpy(&keys->addrs.v6addrs.src, &fl6->saddr, 1700 sizeof(keys->addrs.v6addrs.src)); 1701 memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr, 1702 sizeof(keys->addrs.v6addrs.dst)); 1703 keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1704 keys->ports.src = fl6->fl6_sport; 1705 keys->ports.dst = fl6->fl6_dport; 1706 keys->keyid.keyid = fl6->fl6_gre_key; 1707 keys->tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6); 1708 keys->basic.ip_proto = fl6->flowi6_proto; 1709 1710 return flow_hash_from_keys(keys); 1711 } 1712 EXPORT_SYMBOL(__get_hash_from_flowi6); 1713 1714 static const struct flow_dissector_key flow_keys_dissector_keys[] = { 1715 { 1716 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1717 .offset = offsetof(struct flow_keys, control), 1718 }, 1719 { 1720 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1721 .offset = offsetof(struct flow_keys, basic), 1722 }, 1723 { 1724 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1725 .offset = offsetof(struct flow_keys, addrs.v4addrs), 1726 }, 1727 { 1728 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1729 .offset = offsetof(struct flow_keys, addrs.v6addrs), 1730 }, 1731 { 1732 .key_id = FLOW_DISSECTOR_KEY_TIPC, 1733 .offset = offsetof(struct flow_keys, addrs.tipckey), 1734 }, 1735 { 1736 .key_id = FLOW_DISSECTOR_KEY_PORTS, 1737 .offset = offsetof(struct flow_keys, ports), 1738 }, 1739 { 1740 .key_id = FLOW_DISSECTOR_KEY_VLAN, 1741 .offset = offsetof(struct flow_keys, vlan), 1742 }, 1743 { 1744 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL, 1745 .offset = offsetof(struct flow_keys, tags), 1746 }, 1747 { 1748 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID, 1749 .offset = offsetof(struct flow_keys, keyid), 1750 }, 1751 }; 1752 1753 static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = { 1754 { 1755 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1756 .offset = offsetof(struct flow_keys, control), 1757 }, 1758 { 1759 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1760 .offset = offsetof(struct flow_keys, basic), 1761 }, 1762 { 1763 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1764 .offset = offsetof(struct flow_keys, addrs.v4addrs), 1765 }, 1766 { 1767 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1768 .offset = offsetof(struct flow_keys, addrs.v6addrs), 1769 }, 1770 { 1771 .key_id = FLOW_DISSECTOR_KEY_PORTS, 1772 .offset = offsetof(struct flow_keys, ports), 1773 }, 1774 }; 1775 1776 static const struct flow_dissector_key flow_keys_basic_dissector_keys[] = { 1777 { 1778 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1779 .offset = offsetof(struct flow_keys, control), 1780 }, 1781 { 1782 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1783 .offset = offsetof(struct flow_keys, basic), 1784 }, 1785 }; 1786 1787 struct flow_dissector flow_keys_dissector __read_mostly; 1788 EXPORT_SYMBOL(flow_keys_dissector); 1789 1790 struct flow_dissector flow_keys_basic_dissector __read_mostly; 1791 EXPORT_SYMBOL(flow_keys_basic_dissector); 1792 1793 static int __init init_default_flow_dissectors(void) 1794 { 1795 skb_flow_dissector_init(&flow_keys_dissector, 1796 flow_keys_dissector_keys, 1797 ARRAY_SIZE(flow_keys_dissector_keys)); 1798 skb_flow_dissector_init(&flow_keys_dissector_symmetric, 1799 flow_keys_dissector_symmetric_keys, 1800 ARRAY_SIZE(flow_keys_dissector_symmetric_keys)); 1801 skb_flow_dissector_init(&flow_keys_basic_dissector, 1802 flow_keys_basic_dissector_keys, 1803 ARRAY_SIZE(flow_keys_basic_dissector_keys)); 1804 return 0; 1805 } 1806 core_initcall(init_default_flow_dissectors); 1807