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/dsa.h> 8 #include <net/dst_metadata.h> 9 #include <net/ip.h> 10 #include <net/ipv6.h> 11 #include <net/gre.h> 12 #include <net/pptp.h> 13 #include <net/tipc.h> 14 #include <linux/igmp.h> 15 #include <linux/icmp.h> 16 #include <linux/sctp.h> 17 #include <linux/dccp.h> 18 #include <linux/if_tunnel.h> 19 #include <linux/if_pppox.h> 20 #include <linux/ppp_defs.h> 21 #include <linux/stddef.h> 22 #include <linux/if_ether.h> 23 #include <linux/mpls.h> 24 #include <linux/tcp.h> 25 #include <net/flow_dissector.h> 26 #include <scsi/fc/fc_fcoe.h> 27 #include <uapi/linux/batadv_packet.h> 28 #include <linux/bpf.h> 29 30 static DEFINE_MUTEX(flow_dissector_mutex); 31 32 static void dissector_set_key(struct flow_dissector *flow_dissector, 33 enum flow_dissector_key_id key_id) 34 { 35 flow_dissector->used_keys |= (1 << key_id); 36 } 37 38 void skb_flow_dissector_init(struct flow_dissector *flow_dissector, 39 const struct flow_dissector_key *key, 40 unsigned int key_count) 41 { 42 unsigned int i; 43 44 memset(flow_dissector, 0, sizeof(*flow_dissector)); 45 46 for (i = 0; i < key_count; i++, key++) { 47 /* User should make sure that every key target offset is withing 48 * boundaries of unsigned short. 49 */ 50 BUG_ON(key->offset > USHRT_MAX); 51 BUG_ON(dissector_uses_key(flow_dissector, 52 key->key_id)); 53 54 dissector_set_key(flow_dissector, key->key_id); 55 flow_dissector->offset[key->key_id] = key->offset; 56 } 57 58 /* Ensure that the dissector always includes control and basic key. 59 * That way we are able to avoid handling lack of these in fast path. 60 */ 61 BUG_ON(!dissector_uses_key(flow_dissector, 62 FLOW_DISSECTOR_KEY_CONTROL)); 63 BUG_ON(!dissector_uses_key(flow_dissector, 64 FLOW_DISSECTOR_KEY_BASIC)); 65 } 66 EXPORT_SYMBOL(skb_flow_dissector_init); 67 68 int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, 69 struct bpf_prog *prog) 70 { 71 struct bpf_prog *attached; 72 struct net *net; 73 74 net = current->nsproxy->net_ns; 75 mutex_lock(&flow_dissector_mutex); 76 attached = rcu_dereference_protected(net->flow_dissector_prog, 77 lockdep_is_held(&flow_dissector_mutex)); 78 if (attached) { 79 /* Only one BPF program can be attached at a time */ 80 mutex_unlock(&flow_dissector_mutex); 81 return -EEXIST; 82 } 83 rcu_assign_pointer(net->flow_dissector_prog, prog); 84 mutex_unlock(&flow_dissector_mutex); 85 return 0; 86 } 87 88 int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr) 89 { 90 struct bpf_prog *attached; 91 struct net *net; 92 93 net = current->nsproxy->net_ns; 94 mutex_lock(&flow_dissector_mutex); 95 attached = rcu_dereference_protected(net->flow_dissector_prog, 96 lockdep_is_held(&flow_dissector_mutex)); 97 if (!attached) { 98 mutex_unlock(&flow_dissector_mutex); 99 return -ENOENT; 100 } 101 bpf_prog_put(attached); 102 RCU_INIT_POINTER(net->flow_dissector_prog, NULL); 103 mutex_unlock(&flow_dissector_mutex); 104 return 0; 105 } 106 /** 107 * skb_flow_get_be16 - extract be16 entity 108 * @skb: sk_buff to extract from 109 * @poff: offset to extract at 110 * @data: raw buffer pointer to the packet 111 * @hlen: packet header length 112 * 113 * The function will try to retrieve a be32 entity at 114 * offset poff 115 */ 116 static __be16 skb_flow_get_be16(const struct sk_buff *skb, int poff, 117 void *data, int hlen) 118 { 119 __be16 *u, _u; 120 121 u = __skb_header_pointer(skb, poff, sizeof(_u), data, hlen, &_u); 122 if (u) 123 return *u; 124 125 return 0; 126 } 127 128 /** 129 * __skb_flow_get_ports - extract the upper layer ports and return them 130 * @skb: sk_buff to extract the ports from 131 * @thoff: transport header offset 132 * @ip_proto: protocol for which to get port offset 133 * @data: raw buffer pointer to the packet, if NULL use skb->data 134 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 135 * 136 * The function will try to retrieve the ports at offset thoff + poff where poff 137 * is the protocol port offset returned from proto_ports_offset 138 */ 139 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, 140 void *data, int hlen) 141 { 142 int poff = proto_ports_offset(ip_proto); 143 144 if (!data) { 145 data = skb->data; 146 hlen = skb_headlen(skb); 147 } 148 149 if (poff >= 0) { 150 __be32 *ports, _ports; 151 152 ports = __skb_header_pointer(skb, thoff + poff, 153 sizeof(_ports), data, hlen, &_ports); 154 if (ports) 155 return *ports; 156 } 157 158 return 0; 159 } 160 EXPORT_SYMBOL(__skb_flow_get_ports); 161 162 static void 163 skb_flow_dissect_set_enc_addr_type(enum flow_dissector_key_id type, 164 struct flow_dissector *flow_dissector, 165 void *target_container) 166 { 167 struct flow_dissector_key_control *ctrl; 168 169 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_CONTROL)) 170 return; 171 172 ctrl = skb_flow_dissector_target(flow_dissector, 173 FLOW_DISSECTOR_KEY_ENC_CONTROL, 174 target_container); 175 ctrl->addr_type = type; 176 } 177 178 void 179 skb_flow_dissect_tunnel_info(const struct sk_buff *skb, 180 struct flow_dissector *flow_dissector, 181 void *target_container) 182 { 183 struct ip_tunnel_info *info; 184 struct ip_tunnel_key *key; 185 186 /* A quick check to see if there might be something to do. */ 187 if (!dissector_uses_key(flow_dissector, 188 FLOW_DISSECTOR_KEY_ENC_KEYID) && 189 !dissector_uses_key(flow_dissector, 190 FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS) && 191 !dissector_uses_key(flow_dissector, 192 FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS) && 193 !dissector_uses_key(flow_dissector, 194 FLOW_DISSECTOR_KEY_ENC_CONTROL) && 195 !dissector_uses_key(flow_dissector, 196 FLOW_DISSECTOR_KEY_ENC_PORTS) && 197 !dissector_uses_key(flow_dissector, 198 FLOW_DISSECTOR_KEY_ENC_IP) && 199 !dissector_uses_key(flow_dissector, 200 FLOW_DISSECTOR_KEY_ENC_OPTS)) 201 return; 202 203 info = skb_tunnel_info(skb); 204 if (!info) 205 return; 206 207 key = &info->key; 208 209 switch (ip_tunnel_info_af(info)) { 210 case AF_INET: 211 skb_flow_dissect_set_enc_addr_type(FLOW_DISSECTOR_KEY_IPV4_ADDRS, 212 flow_dissector, 213 target_container); 214 if (dissector_uses_key(flow_dissector, 215 FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS)) { 216 struct flow_dissector_key_ipv4_addrs *ipv4; 217 218 ipv4 = skb_flow_dissector_target(flow_dissector, 219 FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS, 220 target_container); 221 ipv4->src = key->u.ipv4.src; 222 ipv4->dst = key->u.ipv4.dst; 223 } 224 break; 225 case AF_INET6: 226 skb_flow_dissect_set_enc_addr_type(FLOW_DISSECTOR_KEY_IPV6_ADDRS, 227 flow_dissector, 228 target_container); 229 if (dissector_uses_key(flow_dissector, 230 FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS)) { 231 struct flow_dissector_key_ipv6_addrs *ipv6; 232 233 ipv6 = skb_flow_dissector_target(flow_dissector, 234 FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS, 235 target_container); 236 ipv6->src = key->u.ipv6.src; 237 ipv6->dst = key->u.ipv6.dst; 238 } 239 break; 240 } 241 242 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_KEYID)) { 243 struct flow_dissector_key_keyid *keyid; 244 245 keyid = skb_flow_dissector_target(flow_dissector, 246 FLOW_DISSECTOR_KEY_ENC_KEYID, 247 target_container); 248 keyid->keyid = tunnel_id_to_key32(key->tun_id); 249 } 250 251 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_PORTS)) { 252 struct flow_dissector_key_ports *tp; 253 254 tp = skb_flow_dissector_target(flow_dissector, 255 FLOW_DISSECTOR_KEY_ENC_PORTS, 256 target_container); 257 tp->src = key->tp_src; 258 tp->dst = key->tp_dst; 259 } 260 261 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_IP)) { 262 struct flow_dissector_key_ip *ip; 263 264 ip = skb_flow_dissector_target(flow_dissector, 265 FLOW_DISSECTOR_KEY_ENC_IP, 266 target_container); 267 ip->tos = key->tos; 268 ip->ttl = key->ttl; 269 } 270 271 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_OPTS)) { 272 struct flow_dissector_key_enc_opts *enc_opt; 273 274 enc_opt = skb_flow_dissector_target(flow_dissector, 275 FLOW_DISSECTOR_KEY_ENC_OPTS, 276 target_container); 277 278 if (info->options_len) { 279 enc_opt->len = info->options_len; 280 ip_tunnel_info_opts_get(enc_opt->data, info); 281 enc_opt->dst_opt_type = info->key.tun_flags & 282 TUNNEL_OPTIONS_PRESENT; 283 } 284 } 285 } 286 EXPORT_SYMBOL(skb_flow_dissect_tunnel_info); 287 288 static enum flow_dissect_ret 289 __skb_flow_dissect_mpls(const struct sk_buff *skb, 290 struct flow_dissector *flow_dissector, 291 void *target_container, void *data, int nhoff, int hlen) 292 { 293 struct flow_dissector_key_keyid *key_keyid; 294 struct mpls_label *hdr, _hdr[2]; 295 u32 entry, label; 296 297 if (!dissector_uses_key(flow_dissector, 298 FLOW_DISSECTOR_KEY_MPLS_ENTROPY) && 299 !dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS)) 300 return FLOW_DISSECT_RET_OUT_GOOD; 301 302 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, 303 hlen, &_hdr); 304 if (!hdr) 305 return FLOW_DISSECT_RET_OUT_BAD; 306 307 entry = ntohl(hdr[0].entry); 308 label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT; 309 310 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS)) { 311 struct flow_dissector_key_mpls *key_mpls; 312 313 key_mpls = skb_flow_dissector_target(flow_dissector, 314 FLOW_DISSECTOR_KEY_MPLS, 315 target_container); 316 key_mpls->mpls_label = label; 317 key_mpls->mpls_ttl = (entry & MPLS_LS_TTL_MASK) 318 >> MPLS_LS_TTL_SHIFT; 319 key_mpls->mpls_tc = (entry & MPLS_LS_TC_MASK) 320 >> MPLS_LS_TC_SHIFT; 321 key_mpls->mpls_bos = (entry & MPLS_LS_S_MASK) 322 >> MPLS_LS_S_SHIFT; 323 } 324 325 if (label == MPLS_LABEL_ENTROPY) { 326 key_keyid = skb_flow_dissector_target(flow_dissector, 327 FLOW_DISSECTOR_KEY_MPLS_ENTROPY, 328 target_container); 329 key_keyid->keyid = hdr[1].entry & htonl(MPLS_LS_LABEL_MASK); 330 } 331 return FLOW_DISSECT_RET_OUT_GOOD; 332 } 333 334 static enum flow_dissect_ret 335 __skb_flow_dissect_arp(const struct sk_buff *skb, 336 struct flow_dissector *flow_dissector, 337 void *target_container, void *data, int nhoff, int hlen) 338 { 339 struct flow_dissector_key_arp *key_arp; 340 struct { 341 unsigned char ar_sha[ETH_ALEN]; 342 unsigned char ar_sip[4]; 343 unsigned char ar_tha[ETH_ALEN]; 344 unsigned char ar_tip[4]; 345 } *arp_eth, _arp_eth; 346 const struct arphdr *arp; 347 struct arphdr _arp; 348 349 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ARP)) 350 return FLOW_DISSECT_RET_OUT_GOOD; 351 352 arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data, 353 hlen, &_arp); 354 if (!arp) 355 return FLOW_DISSECT_RET_OUT_BAD; 356 357 if (arp->ar_hrd != htons(ARPHRD_ETHER) || 358 arp->ar_pro != htons(ETH_P_IP) || 359 arp->ar_hln != ETH_ALEN || 360 arp->ar_pln != 4 || 361 (arp->ar_op != htons(ARPOP_REPLY) && 362 arp->ar_op != htons(ARPOP_REQUEST))) 363 return FLOW_DISSECT_RET_OUT_BAD; 364 365 arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp), 366 sizeof(_arp_eth), data, 367 hlen, &_arp_eth); 368 if (!arp_eth) 369 return FLOW_DISSECT_RET_OUT_BAD; 370 371 key_arp = skb_flow_dissector_target(flow_dissector, 372 FLOW_DISSECTOR_KEY_ARP, 373 target_container); 374 375 memcpy(&key_arp->sip, arp_eth->ar_sip, sizeof(key_arp->sip)); 376 memcpy(&key_arp->tip, arp_eth->ar_tip, sizeof(key_arp->tip)); 377 378 /* Only store the lower byte of the opcode; 379 * this covers ARPOP_REPLY and ARPOP_REQUEST. 380 */ 381 key_arp->op = ntohs(arp->ar_op) & 0xff; 382 383 ether_addr_copy(key_arp->sha, arp_eth->ar_sha); 384 ether_addr_copy(key_arp->tha, arp_eth->ar_tha); 385 386 return FLOW_DISSECT_RET_OUT_GOOD; 387 } 388 389 static enum flow_dissect_ret 390 __skb_flow_dissect_gre(const struct sk_buff *skb, 391 struct flow_dissector_key_control *key_control, 392 struct flow_dissector *flow_dissector, 393 void *target_container, void *data, 394 __be16 *p_proto, int *p_nhoff, int *p_hlen, 395 unsigned int flags) 396 { 397 struct flow_dissector_key_keyid *key_keyid; 398 struct gre_base_hdr *hdr, _hdr; 399 int offset = 0; 400 u16 gre_ver; 401 402 hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), 403 data, *p_hlen, &_hdr); 404 if (!hdr) 405 return FLOW_DISSECT_RET_OUT_BAD; 406 407 /* Only look inside GRE without routing */ 408 if (hdr->flags & GRE_ROUTING) 409 return FLOW_DISSECT_RET_OUT_GOOD; 410 411 /* Only look inside GRE for version 0 and 1 */ 412 gre_ver = ntohs(hdr->flags & GRE_VERSION); 413 if (gre_ver > 1) 414 return FLOW_DISSECT_RET_OUT_GOOD; 415 416 *p_proto = hdr->protocol; 417 if (gre_ver) { 418 /* Version1 must be PPTP, and check the flags */ 419 if (!(*p_proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY))) 420 return FLOW_DISSECT_RET_OUT_GOOD; 421 } 422 423 offset += sizeof(struct gre_base_hdr); 424 425 if (hdr->flags & GRE_CSUM) 426 offset += FIELD_SIZEOF(struct gre_full_hdr, csum) + 427 FIELD_SIZEOF(struct gre_full_hdr, reserved1); 428 429 if (hdr->flags & GRE_KEY) { 430 const __be32 *keyid; 431 __be32 _keyid; 432 433 keyid = __skb_header_pointer(skb, *p_nhoff + offset, 434 sizeof(_keyid), 435 data, *p_hlen, &_keyid); 436 if (!keyid) 437 return FLOW_DISSECT_RET_OUT_BAD; 438 439 if (dissector_uses_key(flow_dissector, 440 FLOW_DISSECTOR_KEY_GRE_KEYID)) { 441 key_keyid = skb_flow_dissector_target(flow_dissector, 442 FLOW_DISSECTOR_KEY_GRE_KEYID, 443 target_container); 444 if (gre_ver == 0) 445 key_keyid->keyid = *keyid; 446 else 447 key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK; 448 } 449 offset += FIELD_SIZEOF(struct gre_full_hdr, key); 450 } 451 452 if (hdr->flags & GRE_SEQ) 453 offset += FIELD_SIZEOF(struct pptp_gre_header, seq); 454 455 if (gre_ver == 0) { 456 if (*p_proto == htons(ETH_P_TEB)) { 457 const struct ethhdr *eth; 458 struct ethhdr _eth; 459 460 eth = __skb_header_pointer(skb, *p_nhoff + offset, 461 sizeof(_eth), 462 data, *p_hlen, &_eth); 463 if (!eth) 464 return FLOW_DISSECT_RET_OUT_BAD; 465 *p_proto = eth->h_proto; 466 offset += sizeof(*eth); 467 468 /* Cap headers that we access via pointers at the 469 * end of the Ethernet header as our maximum alignment 470 * at that point is only 2 bytes. 471 */ 472 if (NET_IP_ALIGN) 473 *p_hlen = *p_nhoff + offset; 474 } 475 } else { /* version 1, must be PPTP */ 476 u8 _ppp_hdr[PPP_HDRLEN]; 477 u8 *ppp_hdr; 478 479 if (hdr->flags & GRE_ACK) 480 offset += FIELD_SIZEOF(struct pptp_gre_header, ack); 481 482 ppp_hdr = __skb_header_pointer(skb, *p_nhoff + offset, 483 sizeof(_ppp_hdr), 484 data, *p_hlen, _ppp_hdr); 485 if (!ppp_hdr) 486 return FLOW_DISSECT_RET_OUT_BAD; 487 488 switch (PPP_PROTOCOL(ppp_hdr)) { 489 case PPP_IP: 490 *p_proto = htons(ETH_P_IP); 491 break; 492 case PPP_IPV6: 493 *p_proto = htons(ETH_P_IPV6); 494 break; 495 default: 496 /* Could probably catch some more like MPLS */ 497 break; 498 } 499 500 offset += PPP_HDRLEN; 501 } 502 503 *p_nhoff += offset; 504 key_control->flags |= FLOW_DIS_ENCAPSULATION; 505 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 506 return FLOW_DISSECT_RET_OUT_GOOD; 507 508 return FLOW_DISSECT_RET_PROTO_AGAIN; 509 } 510 511 /** 512 * __skb_flow_dissect_batadv() - dissect batman-adv header 513 * @skb: sk_buff to with the batman-adv header 514 * @key_control: flow dissectors control key 515 * @data: raw buffer pointer to the packet, if NULL use skb->data 516 * @p_proto: pointer used to update the protocol to process next 517 * @p_nhoff: pointer used to update inner network header offset 518 * @hlen: packet header length 519 * @flags: any combination of FLOW_DISSECTOR_F_* 520 * 521 * ETH_P_BATMAN packets are tried to be dissected. Only 522 * &struct batadv_unicast packets are actually processed because they contain an 523 * inner ethernet header and are usually followed by actual network header. This 524 * allows the flow dissector to continue processing the packet. 525 * 526 * Return: FLOW_DISSECT_RET_PROTO_AGAIN when &struct batadv_unicast was found, 527 * FLOW_DISSECT_RET_OUT_GOOD when dissector should stop after encapsulation, 528 * otherwise FLOW_DISSECT_RET_OUT_BAD 529 */ 530 static enum flow_dissect_ret 531 __skb_flow_dissect_batadv(const struct sk_buff *skb, 532 struct flow_dissector_key_control *key_control, 533 void *data, __be16 *p_proto, int *p_nhoff, int hlen, 534 unsigned int flags) 535 { 536 struct { 537 struct batadv_unicast_packet batadv_unicast; 538 struct ethhdr eth; 539 } *hdr, _hdr; 540 541 hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), data, hlen, 542 &_hdr); 543 if (!hdr) 544 return FLOW_DISSECT_RET_OUT_BAD; 545 546 if (hdr->batadv_unicast.version != BATADV_COMPAT_VERSION) 547 return FLOW_DISSECT_RET_OUT_BAD; 548 549 if (hdr->batadv_unicast.packet_type != BATADV_UNICAST) 550 return FLOW_DISSECT_RET_OUT_BAD; 551 552 *p_proto = hdr->eth.h_proto; 553 *p_nhoff += sizeof(*hdr); 554 555 key_control->flags |= FLOW_DIS_ENCAPSULATION; 556 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) 557 return FLOW_DISSECT_RET_OUT_GOOD; 558 559 return FLOW_DISSECT_RET_PROTO_AGAIN; 560 } 561 562 static void 563 __skb_flow_dissect_tcp(const struct sk_buff *skb, 564 struct flow_dissector *flow_dissector, 565 void *target_container, void *data, int thoff, int hlen) 566 { 567 struct flow_dissector_key_tcp *key_tcp; 568 struct tcphdr *th, _th; 569 570 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_TCP)) 571 return; 572 573 th = __skb_header_pointer(skb, thoff, sizeof(_th), data, hlen, &_th); 574 if (!th) 575 return; 576 577 if (unlikely(__tcp_hdrlen(th) < sizeof(_th))) 578 return; 579 580 key_tcp = skb_flow_dissector_target(flow_dissector, 581 FLOW_DISSECTOR_KEY_TCP, 582 target_container); 583 key_tcp->flags = (*(__be16 *) &tcp_flag_word(th) & htons(0x0FFF)); 584 } 585 586 static void 587 __skb_flow_dissect_ipv4(const struct sk_buff *skb, 588 struct flow_dissector *flow_dissector, 589 void *target_container, void *data, const struct iphdr *iph) 590 { 591 struct flow_dissector_key_ip *key_ip; 592 593 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP)) 594 return; 595 596 key_ip = skb_flow_dissector_target(flow_dissector, 597 FLOW_DISSECTOR_KEY_IP, 598 target_container); 599 key_ip->tos = iph->tos; 600 key_ip->ttl = iph->ttl; 601 } 602 603 static void 604 __skb_flow_dissect_ipv6(const struct sk_buff *skb, 605 struct flow_dissector *flow_dissector, 606 void *target_container, void *data, const struct ipv6hdr *iph) 607 { 608 struct flow_dissector_key_ip *key_ip; 609 610 if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP)) 611 return; 612 613 key_ip = skb_flow_dissector_target(flow_dissector, 614 FLOW_DISSECTOR_KEY_IP, 615 target_container); 616 key_ip->tos = ipv6_get_dsfield(iph); 617 key_ip->ttl = iph->hop_limit; 618 } 619 620 /* Maximum number of protocol headers that can be parsed in 621 * __skb_flow_dissect 622 */ 623 #define MAX_FLOW_DISSECT_HDRS 15 624 625 static bool skb_flow_dissect_allowed(int *num_hdrs) 626 { 627 ++*num_hdrs; 628 629 return (*num_hdrs <= MAX_FLOW_DISSECT_HDRS); 630 } 631 632 static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys, 633 struct flow_dissector *flow_dissector, 634 void *target_container) 635 { 636 struct flow_dissector_key_control *key_control; 637 struct flow_dissector_key_basic *key_basic; 638 struct flow_dissector_key_addrs *key_addrs; 639 struct flow_dissector_key_ports *key_ports; 640 641 key_control = skb_flow_dissector_target(flow_dissector, 642 FLOW_DISSECTOR_KEY_CONTROL, 643 target_container); 644 key_control->thoff = flow_keys->thoff; 645 if (flow_keys->is_frag) 646 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 647 if (flow_keys->is_first_frag) 648 key_control->flags |= FLOW_DIS_FIRST_FRAG; 649 if (flow_keys->is_encap) 650 key_control->flags |= FLOW_DIS_ENCAPSULATION; 651 652 key_basic = skb_flow_dissector_target(flow_dissector, 653 FLOW_DISSECTOR_KEY_BASIC, 654 target_container); 655 key_basic->n_proto = flow_keys->n_proto; 656 key_basic->ip_proto = flow_keys->ip_proto; 657 658 if (flow_keys->addr_proto == ETH_P_IP && 659 dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IPV4_ADDRS)) { 660 key_addrs = skb_flow_dissector_target(flow_dissector, 661 FLOW_DISSECTOR_KEY_IPV4_ADDRS, 662 target_container); 663 key_addrs->v4addrs.src = flow_keys->ipv4_src; 664 key_addrs->v4addrs.dst = flow_keys->ipv4_dst; 665 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 666 } else if (flow_keys->addr_proto == ETH_P_IPV6 && 667 dissector_uses_key(flow_dissector, 668 FLOW_DISSECTOR_KEY_IPV6_ADDRS)) { 669 key_addrs = skb_flow_dissector_target(flow_dissector, 670 FLOW_DISSECTOR_KEY_IPV6_ADDRS, 671 target_container); 672 memcpy(&key_addrs->v6addrs, &flow_keys->ipv6_src, 673 sizeof(key_addrs->v6addrs)); 674 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 675 } 676 677 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS)) { 678 key_ports = skb_flow_dissector_target(flow_dissector, 679 FLOW_DISSECTOR_KEY_PORTS, 680 target_container); 681 key_ports->src = flow_keys->sport; 682 key_ports->dst = flow_keys->dport; 683 } 684 } 685 686 /** 687 * __skb_flow_dissect - extract the flow_keys struct and return it 688 * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified 689 * @flow_dissector: list of keys to dissect 690 * @target_container: target structure to put dissected values into 691 * @data: raw buffer pointer to the packet, if NULL use skb->data 692 * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol 693 * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb) 694 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 695 * 696 * The function will try to retrieve individual keys into target specified 697 * by flow_dissector from either the skbuff or a raw buffer specified by the 698 * rest parameters. 699 * 700 * Caller must take care of zeroing target container memory. 701 */ 702 bool __skb_flow_dissect(const struct sk_buff *skb, 703 struct flow_dissector *flow_dissector, 704 void *target_container, 705 void *data, __be16 proto, int nhoff, int hlen, 706 unsigned int flags) 707 { 708 struct flow_dissector_key_control *key_control; 709 struct flow_dissector_key_basic *key_basic; 710 struct flow_dissector_key_addrs *key_addrs; 711 struct flow_dissector_key_ports *key_ports; 712 struct flow_dissector_key_icmp *key_icmp; 713 struct flow_dissector_key_tags *key_tags; 714 struct flow_dissector_key_vlan *key_vlan; 715 enum flow_dissect_ret fdret; 716 enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX; 717 struct bpf_prog *attached = NULL; 718 int num_hdrs = 0; 719 u8 ip_proto = 0; 720 bool ret; 721 722 if (!data) { 723 data = skb->data; 724 proto = skb_vlan_tag_present(skb) ? 725 skb->vlan_proto : skb->protocol; 726 nhoff = skb_network_offset(skb); 727 hlen = skb_headlen(skb); 728 #if IS_ENABLED(CONFIG_NET_DSA) 729 if (unlikely(skb->dev && netdev_uses_dsa(skb->dev))) { 730 const struct dsa_device_ops *ops; 731 int offset; 732 733 ops = skb->dev->dsa_ptr->tag_ops; 734 if (ops->flow_dissect && 735 !ops->flow_dissect(skb, &proto, &offset)) { 736 hlen -= offset; 737 nhoff += offset; 738 } 739 } 740 #endif 741 } 742 743 /* It is ensured by skb_flow_dissector_init() that control key will 744 * be always present. 745 */ 746 key_control = skb_flow_dissector_target(flow_dissector, 747 FLOW_DISSECTOR_KEY_CONTROL, 748 target_container); 749 750 /* It is ensured by skb_flow_dissector_init() that basic key will 751 * be always present. 752 */ 753 key_basic = skb_flow_dissector_target(flow_dissector, 754 FLOW_DISSECTOR_KEY_BASIC, 755 target_container); 756 757 rcu_read_lock(); 758 if (skb) { 759 if (skb->dev) 760 attached = rcu_dereference(dev_net(skb->dev)->flow_dissector_prog); 761 else if (skb->sk) 762 attached = rcu_dereference(sock_net(skb->sk)->flow_dissector_prog); 763 else 764 WARN_ON_ONCE(1); 765 } 766 if (attached) { 767 /* Note that even though the const qualifier is discarded 768 * throughout the execution of the BPF program, all changes(the 769 * control block) are reverted after the BPF program returns. 770 * Therefore, __skb_flow_dissect does not alter the skb. 771 */ 772 struct bpf_flow_keys flow_keys = {}; 773 struct bpf_skb_data_end cb_saved; 774 struct bpf_skb_data_end *cb; 775 u32 result; 776 777 cb = (struct bpf_skb_data_end *)skb->cb; 778 779 /* Save Control Block */ 780 memcpy(&cb_saved, cb, sizeof(cb_saved)); 781 memset(cb, 0, sizeof(cb_saved)); 782 783 /* Pass parameters to the BPF program */ 784 cb->qdisc_cb.flow_keys = &flow_keys; 785 flow_keys.nhoff = nhoff; 786 787 bpf_compute_data_pointers((struct sk_buff *)skb); 788 result = BPF_PROG_RUN(attached, skb); 789 790 /* Restore state */ 791 memcpy(cb, &cb_saved, sizeof(cb_saved)); 792 793 __skb_flow_bpf_to_target(&flow_keys, flow_dissector, 794 target_container); 795 key_control->thoff = min_t(u16, key_control->thoff, skb->len); 796 rcu_read_unlock(); 797 return result == BPF_OK; 798 } 799 rcu_read_unlock(); 800 801 if (dissector_uses_key(flow_dissector, 802 FLOW_DISSECTOR_KEY_ETH_ADDRS)) { 803 struct ethhdr *eth = eth_hdr(skb); 804 struct flow_dissector_key_eth_addrs *key_eth_addrs; 805 806 key_eth_addrs = skb_flow_dissector_target(flow_dissector, 807 FLOW_DISSECTOR_KEY_ETH_ADDRS, 808 target_container); 809 memcpy(key_eth_addrs, ð->h_dest, sizeof(*key_eth_addrs)); 810 } 811 812 proto_again: 813 fdret = FLOW_DISSECT_RET_CONTINUE; 814 815 switch (proto) { 816 case htons(ETH_P_IP): { 817 const struct iphdr *iph; 818 struct iphdr _iph; 819 820 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 821 if (!iph || iph->ihl < 5) { 822 fdret = FLOW_DISSECT_RET_OUT_BAD; 823 break; 824 } 825 826 nhoff += iph->ihl * 4; 827 828 ip_proto = iph->protocol; 829 830 if (dissector_uses_key(flow_dissector, 831 FLOW_DISSECTOR_KEY_IPV4_ADDRS)) { 832 key_addrs = skb_flow_dissector_target(flow_dissector, 833 FLOW_DISSECTOR_KEY_IPV4_ADDRS, 834 target_container); 835 836 memcpy(&key_addrs->v4addrs, &iph->saddr, 837 sizeof(key_addrs->v4addrs)); 838 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 839 } 840 841 if (ip_is_fragment(iph)) { 842 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 843 844 if (iph->frag_off & htons(IP_OFFSET)) { 845 fdret = FLOW_DISSECT_RET_OUT_GOOD; 846 break; 847 } else { 848 key_control->flags |= FLOW_DIS_FIRST_FRAG; 849 if (!(flags & 850 FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) { 851 fdret = FLOW_DISSECT_RET_OUT_GOOD; 852 break; 853 } 854 } 855 } 856 857 __skb_flow_dissect_ipv4(skb, flow_dissector, 858 target_container, data, iph); 859 860 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) { 861 fdret = FLOW_DISSECT_RET_OUT_GOOD; 862 break; 863 } 864 865 break; 866 } 867 case htons(ETH_P_IPV6): { 868 const struct ipv6hdr *iph; 869 struct ipv6hdr _iph; 870 871 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 872 if (!iph) { 873 fdret = FLOW_DISSECT_RET_OUT_BAD; 874 break; 875 } 876 877 ip_proto = iph->nexthdr; 878 nhoff += sizeof(struct ipv6hdr); 879 880 if (dissector_uses_key(flow_dissector, 881 FLOW_DISSECTOR_KEY_IPV6_ADDRS)) { 882 key_addrs = skb_flow_dissector_target(flow_dissector, 883 FLOW_DISSECTOR_KEY_IPV6_ADDRS, 884 target_container); 885 886 memcpy(&key_addrs->v6addrs, &iph->saddr, 887 sizeof(key_addrs->v6addrs)); 888 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 889 } 890 891 if ((dissector_uses_key(flow_dissector, 892 FLOW_DISSECTOR_KEY_FLOW_LABEL) || 893 (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) && 894 ip6_flowlabel(iph)) { 895 __be32 flow_label = ip6_flowlabel(iph); 896 897 if (dissector_uses_key(flow_dissector, 898 FLOW_DISSECTOR_KEY_FLOW_LABEL)) { 899 key_tags = skb_flow_dissector_target(flow_dissector, 900 FLOW_DISSECTOR_KEY_FLOW_LABEL, 901 target_container); 902 key_tags->flow_label = ntohl(flow_label); 903 } 904 if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) { 905 fdret = FLOW_DISSECT_RET_OUT_GOOD; 906 break; 907 } 908 } 909 910 __skb_flow_dissect_ipv6(skb, flow_dissector, 911 target_container, data, iph); 912 913 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) 914 fdret = FLOW_DISSECT_RET_OUT_GOOD; 915 916 break; 917 } 918 case htons(ETH_P_8021AD): 919 case htons(ETH_P_8021Q): { 920 const struct vlan_hdr *vlan = NULL; 921 struct vlan_hdr _vlan; 922 __be16 saved_vlan_tpid = proto; 923 924 if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX && 925 skb && skb_vlan_tag_present(skb)) { 926 proto = skb->protocol; 927 } else { 928 vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), 929 data, hlen, &_vlan); 930 if (!vlan) { 931 fdret = FLOW_DISSECT_RET_OUT_BAD; 932 break; 933 } 934 935 proto = vlan->h_vlan_encapsulated_proto; 936 nhoff += sizeof(*vlan); 937 } 938 939 if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX) { 940 dissector_vlan = FLOW_DISSECTOR_KEY_VLAN; 941 } else if (dissector_vlan == FLOW_DISSECTOR_KEY_VLAN) { 942 dissector_vlan = FLOW_DISSECTOR_KEY_CVLAN; 943 } else { 944 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 945 break; 946 } 947 948 if (dissector_uses_key(flow_dissector, dissector_vlan)) { 949 key_vlan = skb_flow_dissector_target(flow_dissector, 950 dissector_vlan, 951 target_container); 952 953 if (!vlan) { 954 key_vlan->vlan_id = skb_vlan_tag_get_id(skb); 955 key_vlan->vlan_priority = 956 (skb_vlan_tag_get_prio(skb) >> VLAN_PRIO_SHIFT); 957 } else { 958 key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) & 959 VLAN_VID_MASK; 960 key_vlan->vlan_priority = 961 (ntohs(vlan->h_vlan_TCI) & 962 VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; 963 } 964 key_vlan->vlan_tpid = saved_vlan_tpid; 965 } 966 967 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 968 break; 969 } 970 case htons(ETH_P_PPP_SES): { 971 struct { 972 struct pppoe_hdr hdr; 973 __be16 proto; 974 } *hdr, _hdr; 975 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 976 if (!hdr) { 977 fdret = FLOW_DISSECT_RET_OUT_BAD; 978 break; 979 } 980 981 proto = hdr->proto; 982 nhoff += PPPOE_SES_HLEN; 983 switch (proto) { 984 case htons(PPP_IP): 985 proto = htons(ETH_P_IP); 986 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 987 break; 988 case htons(PPP_IPV6): 989 proto = htons(ETH_P_IPV6); 990 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 991 break; 992 default: 993 fdret = FLOW_DISSECT_RET_OUT_BAD; 994 break; 995 } 996 break; 997 } 998 case htons(ETH_P_TIPC): { 999 struct tipc_basic_hdr *hdr, _hdr; 1000 1001 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), 1002 data, hlen, &_hdr); 1003 if (!hdr) { 1004 fdret = FLOW_DISSECT_RET_OUT_BAD; 1005 break; 1006 } 1007 1008 if (dissector_uses_key(flow_dissector, 1009 FLOW_DISSECTOR_KEY_TIPC)) { 1010 key_addrs = skb_flow_dissector_target(flow_dissector, 1011 FLOW_DISSECTOR_KEY_TIPC, 1012 target_container); 1013 key_addrs->tipckey.key = tipc_hdr_rps_key(hdr); 1014 key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC; 1015 } 1016 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1017 break; 1018 } 1019 1020 case htons(ETH_P_MPLS_UC): 1021 case htons(ETH_P_MPLS_MC): 1022 fdret = __skb_flow_dissect_mpls(skb, flow_dissector, 1023 target_container, data, 1024 nhoff, hlen); 1025 break; 1026 case htons(ETH_P_FCOE): 1027 if ((hlen - nhoff) < FCOE_HEADER_LEN) { 1028 fdret = FLOW_DISSECT_RET_OUT_BAD; 1029 break; 1030 } 1031 1032 nhoff += FCOE_HEADER_LEN; 1033 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1034 break; 1035 1036 case htons(ETH_P_ARP): 1037 case htons(ETH_P_RARP): 1038 fdret = __skb_flow_dissect_arp(skb, flow_dissector, 1039 target_container, data, 1040 nhoff, hlen); 1041 break; 1042 1043 case htons(ETH_P_BATMAN): 1044 fdret = __skb_flow_dissect_batadv(skb, key_control, data, 1045 &proto, &nhoff, hlen, flags); 1046 break; 1047 1048 default: 1049 fdret = FLOW_DISSECT_RET_OUT_BAD; 1050 break; 1051 } 1052 1053 /* Process result of proto processing */ 1054 switch (fdret) { 1055 case FLOW_DISSECT_RET_OUT_GOOD: 1056 goto out_good; 1057 case FLOW_DISSECT_RET_PROTO_AGAIN: 1058 if (skb_flow_dissect_allowed(&num_hdrs)) 1059 goto proto_again; 1060 goto out_good; 1061 case FLOW_DISSECT_RET_CONTINUE: 1062 case FLOW_DISSECT_RET_IPPROTO_AGAIN: 1063 break; 1064 case FLOW_DISSECT_RET_OUT_BAD: 1065 default: 1066 goto out_bad; 1067 } 1068 1069 ip_proto_again: 1070 fdret = FLOW_DISSECT_RET_CONTINUE; 1071 1072 switch (ip_proto) { 1073 case IPPROTO_GRE: 1074 fdret = __skb_flow_dissect_gre(skb, key_control, flow_dissector, 1075 target_container, data, 1076 &proto, &nhoff, &hlen, flags); 1077 break; 1078 1079 case NEXTHDR_HOP: 1080 case NEXTHDR_ROUTING: 1081 case NEXTHDR_DEST: { 1082 u8 _opthdr[2], *opthdr; 1083 1084 if (proto != htons(ETH_P_IPV6)) 1085 break; 1086 1087 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr), 1088 data, hlen, &_opthdr); 1089 if (!opthdr) { 1090 fdret = FLOW_DISSECT_RET_OUT_BAD; 1091 break; 1092 } 1093 1094 ip_proto = opthdr[0]; 1095 nhoff += (opthdr[1] + 1) << 3; 1096 1097 fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN; 1098 break; 1099 } 1100 case NEXTHDR_FRAGMENT: { 1101 struct frag_hdr _fh, *fh; 1102 1103 if (proto != htons(ETH_P_IPV6)) 1104 break; 1105 1106 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh), 1107 data, hlen, &_fh); 1108 1109 if (!fh) { 1110 fdret = FLOW_DISSECT_RET_OUT_BAD; 1111 break; 1112 } 1113 1114 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 1115 1116 nhoff += sizeof(_fh); 1117 ip_proto = fh->nexthdr; 1118 1119 if (!(fh->frag_off & htons(IP6_OFFSET))) { 1120 key_control->flags |= FLOW_DIS_FIRST_FRAG; 1121 if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) { 1122 fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN; 1123 break; 1124 } 1125 } 1126 1127 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1128 break; 1129 } 1130 case IPPROTO_IPIP: 1131 proto = htons(ETH_P_IP); 1132 1133 key_control->flags |= FLOW_DIS_ENCAPSULATION; 1134 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) { 1135 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1136 break; 1137 } 1138 1139 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1140 break; 1141 1142 case IPPROTO_IPV6: 1143 proto = htons(ETH_P_IPV6); 1144 1145 key_control->flags |= FLOW_DIS_ENCAPSULATION; 1146 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) { 1147 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1148 break; 1149 } 1150 1151 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1152 break; 1153 1154 1155 case IPPROTO_MPLS: 1156 proto = htons(ETH_P_MPLS_UC); 1157 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1158 break; 1159 1160 case IPPROTO_TCP: 1161 __skb_flow_dissect_tcp(skb, flow_dissector, target_container, 1162 data, nhoff, hlen); 1163 break; 1164 1165 default: 1166 break; 1167 } 1168 1169 if (dissector_uses_key(flow_dissector, 1170 FLOW_DISSECTOR_KEY_PORTS)) { 1171 key_ports = skb_flow_dissector_target(flow_dissector, 1172 FLOW_DISSECTOR_KEY_PORTS, 1173 target_container); 1174 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto, 1175 data, hlen); 1176 } 1177 1178 if (dissector_uses_key(flow_dissector, 1179 FLOW_DISSECTOR_KEY_ICMP)) { 1180 key_icmp = skb_flow_dissector_target(flow_dissector, 1181 FLOW_DISSECTOR_KEY_ICMP, 1182 target_container); 1183 key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen); 1184 } 1185 1186 /* Process result of IP proto processing */ 1187 switch (fdret) { 1188 case FLOW_DISSECT_RET_PROTO_AGAIN: 1189 if (skb_flow_dissect_allowed(&num_hdrs)) 1190 goto proto_again; 1191 break; 1192 case FLOW_DISSECT_RET_IPPROTO_AGAIN: 1193 if (skb_flow_dissect_allowed(&num_hdrs)) 1194 goto ip_proto_again; 1195 break; 1196 case FLOW_DISSECT_RET_OUT_GOOD: 1197 case FLOW_DISSECT_RET_CONTINUE: 1198 break; 1199 case FLOW_DISSECT_RET_OUT_BAD: 1200 default: 1201 goto out_bad; 1202 } 1203 1204 out_good: 1205 ret = true; 1206 1207 out: 1208 key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen); 1209 key_basic->n_proto = proto; 1210 key_basic->ip_proto = ip_proto; 1211 1212 return ret; 1213 1214 out_bad: 1215 ret = false; 1216 goto out; 1217 } 1218 EXPORT_SYMBOL(__skb_flow_dissect); 1219 1220 static u32 hashrnd __read_mostly; 1221 static __always_inline void __flow_hash_secret_init(void) 1222 { 1223 net_get_random_once(&hashrnd, sizeof(hashrnd)); 1224 } 1225 1226 static __always_inline u32 __flow_hash_words(const u32 *words, u32 length, 1227 u32 keyval) 1228 { 1229 return jhash2(words, length, keyval); 1230 } 1231 1232 static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow) 1233 { 1234 const void *p = flow; 1235 1236 BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32)); 1237 return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET); 1238 } 1239 1240 static inline size_t flow_keys_hash_length(const struct flow_keys *flow) 1241 { 1242 size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs); 1243 BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32)); 1244 BUILD_BUG_ON(offsetof(typeof(*flow), addrs) != 1245 sizeof(*flow) - sizeof(flow->addrs)); 1246 1247 switch (flow->control.addr_type) { 1248 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1249 diff -= sizeof(flow->addrs.v4addrs); 1250 break; 1251 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1252 diff -= sizeof(flow->addrs.v6addrs); 1253 break; 1254 case FLOW_DISSECTOR_KEY_TIPC: 1255 diff -= sizeof(flow->addrs.tipckey); 1256 break; 1257 } 1258 return (sizeof(*flow) - diff) / sizeof(u32); 1259 } 1260 1261 __be32 flow_get_u32_src(const struct flow_keys *flow) 1262 { 1263 switch (flow->control.addr_type) { 1264 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1265 return flow->addrs.v4addrs.src; 1266 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1267 return (__force __be32)ipv6_addr_hash( 1268 &flow->addrs.v6addrs.src); 1269 case FLOW_DISSECTOR_KEY_TIPC: 1270 return flow->addrs.tipckey.key; 1271 default: 1272 return 0; 1273 } 1274 } 1275 EXPORT_SYMBOL(flow_get_u32_src); 1276 1277 __be32 flow_get_u32_dst(const struct flow_keys *flow) 1278 { 1279 switch (flow->control.addr_type) { 1280 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1281 return flow->addrs.v4addrs.dst; 1282 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1283 return (__force __be32)ipv6_addr_hash( 1284 &flow->addrs.v6addrs.dst); 1285 default: 1286 return 0; 1287 } 1288 } 1289 EXPORT_SYMBOL(flow_get_u32_dst); 1290 1291 static inline void __flow_hash_consistentify(struct flow_keys *keys) 1292 { 1293 int addr_diff, i; 1294 1295 switch (keys->control.addr_type) { 1296 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1297 addr_diff = (__force u32)keys->addrs.v4addrs.dst - 1298 (__force u32)keys->addrs.v4addrs.src; 1299 if ((addr_diff < 0) || 1300 (addr_diff == 0 && 1301 ((__force u16)keys->ports.dst < 1302 (__force u16)keys->ports.src))) { 1303 swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst); 1304 swap(keys->ports.src, keys->ports.dst); 1305 } 1306 break; 1307 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1308 addr_diff = memcmp(&keys->addrs.v6addrs.dst, 1309 &keys->addrs.v6addrs.src, 1310 sizeof(keys->addrs.v6addrs.dst)); 1311 if ((addr_diff < 0) || 1312 (addr_diff == 0 && 1313 ((__force u16)keys->ports.dst < 1314 (__force u16)keys->ports.src))) { 1315 for (i = 0; i < 4; i++) 1316 swap(keys->addrs.v6addrs.src.s6_addr32[i], 1317 keys->addrs.v6addrs.dst.s6_addr32[i]); 1318 swap(keys->ports.src, keys->ports.dst); 1319 } 1320 break; 1321 } 1322 } 1323 1324 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval) 1325 { 1326 u32 hash; 1327 1328 __flow_hash_consistentify(keys); 1329 1330 hash = __flow_hash_words(flow_keys_hash_start(keys), 1331 flow_keys_hash_length(keys), keyval); 1332 if (!hash) 1333 hash = 1; 1334 1335 return hash; 1336 } 1337 1338 u32 flow_hash_from_keys(struct flow_keys *keys) 1339 { 1340 __flow_hash_secret_init(); 1341 return __flow_hash_from_keys(keys, hashrnd); 1342 } 1343 EXPORT_SYMBOL(flow_hash_from_keys); 1344 1345 static inline u32 ___skb_get_hash(const struct sk_buff *skb, 1346 struct flow_keys *keys, u32 keyval) 1347 { 1348 skb_flow_dissect_flow_keys(skb, keys, 1349 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 1350 1351 return __flow_hash_from_keys(keys, keyval); 1352 } 1353 1354 struct _flow_keys_digest_data { 1355 __be16 n_proto; 1356 u8 ip_proto; 1357 u8 padding; 1358 __be32 ports; 1359 __be32 src; 1360 __be32 dst; 1361 }; 1362 1363 void make_flow_keys_digest(struct flow_keys_digest *digest, 1364 const struct flow_keys *flow) 1365 { 1366 struct _flow_keys_digest_data *data = 1367 (struct _flow_keys_digest_data *)digest; 1368 1369 BUILD_BUG_ON(sizeof(*data) > sizeof(*digest)); 1370 1371 memset(digest, 0, sizeof(*digest)); 1372 1373 data->n_proto = flow->basic.n_proto; 1374 data->ip_proto = flow->basic.ip_proto; 1375 data->ports = flow->ports.ports; 1376 data->src = flow->addrs.v4addrs.src; 1377 data->dst = flow->addrs.v4addrs.dst; 1378 } 1379 EXPORT_SYMBOL(make_flow_keys_digest); 1380 1381 static struct flow_dissector flow_keys_dissector_symmetric __read_mostly; 1382 1383 u32 __skb_get_hash_symmetric(const struct sk_buff *skb) 1384 { 1385 struct flow_keys keys; 1386 1387 __flow_hash_secret_init(); 1388 1389 memset(&keys, 0, sizeof(keys)); 1390 __skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys, 1391 NULL, 0, 0, 0, 1392 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 1393 1394 return __flow_hash_from_keys(&keys, hashrnd); 1395 } 1396 EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric); 1397 1398 /** 1399 * __skb_get_hash: calculate a flow hash 1400 * @skb: sk_buff to calculate flow hash from 1401 * 1402 * This function calculates a flow hash based on src/dst addresses 1403 * and src/dst port numbers. Sets hash in skb to non-zero hash value 1404 * on success, zero indicates no valid hash. Also, sets l4_hash in skb 1405 * if hash is a canonical 4-tuple hash over transport ports. 1406 */ 1407 void __skb_get_hash(struct sk_buff *skb) 1408 { 1409 struct flow_keys keys; 1410 u32 hash; 1411 1412 __flow_hash_secret_init(); 1413 1414 hash = ___skb_get_hash(skb, &keys, hashrnd); 1415 1416 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys)); 1417 } 1418 EXPORT_SYMBOL(__skb_get_hash); 1419 1420 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb) 1421 { 1422 struct flow_keys keys; 1423 1424 return ___skb_get_hash(skb, &keys, perturb); 1425 } 1426 EXPORT_SYMBOL(skb_get_hash_perturb); 1427 1428 u32 __skb_get_poff(const struct sk_buff *skb, void *data, 1429 const struct flow_keys_basic *keys, int hlen) 1430 { 1431 u32 poff = keys->control.thoff; 1432 1433 /* skip L4 headers for fragments after the first */ 1434 if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) && 1435 !(keys->control.flags & FLOW_DIS_FIRST_FRAG)) 1436 return poff; 1437 1438 switch (keys->basic.ip_proto) { 1439 case IPPROTO_TCP: { 1440 /* access doff as u8 to avoid unaligned access */ 1441 const u8 *doff; 1442 u8 _doff; 1443 1444 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff), 1445 data, hlen, &_doff); 1446 if (!doff) 1447 return poff; 1448 1449 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2); 1450 break; 1451 } 1452 case IPPROTO_UDP: 1453 case IPPROTO_UDPLITE: 1454 poff += sizeof(struct udphdr); 1455 break; 1456 /* For the rest, we do not really care about header 1457 * extensions at this point for now. 1458 */ 1459 case IPPROTO_ICMP: 1460 poff += sizeof(struct icmphdr); 1461 break; 1462 case IPPROTO_ICMPV6: 1463 poff += sizeof(struct icmp6hdr); 1464 break; 1465 case IPPROTO_IGMP: 1466 poff += sizeof(struct igmphdr); 1467 break; 1468 case IPPROTO_DCCP: 1469 poff += sizeof(struct dccp_hdr); 1470 break; 1471 case IPPROTO_SCTP: 1472 poff += sizeof(struct sctphdr); 1473 break; 1474 } 1475 1476 return poff; 1477 } 1478 1479 /** 1480 * skb_get_poff - get the offset to the payload 1481 * @skb: sk_buff to get the payload offset from 1482 * 1483 * The function will get the offset to the payload as far as it could 1484 * be dissected. The main user is currently BPF, so that we can dynamically 1485 * truncate packets without needing to push actual payload to the user 1486 * space and can analyze headers only, instead. 1487 */ 1488 u32 skb_get_poff(const struct sk_buff *skb) 1489 { 1490 struct flow_keys_basic keys; 1491 1492 if (!skb_flow_dissect_flow_keys_basic(skb, &keys, NULL, 0, 0, 0, 0)) 1493 return 0; 1494 1495 return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb)); 1496 } 1497 1498 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys) 1499 { 1500 memset(keys, 0, sizeof(*keys)); 1501 1502 memcpy(&keys->addrs.v6addrs.src, &fl6->saddr, 1503 sizeof(keys->addrs.v6addrs.src)); 1504 memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr, 1505 sizeof(keys->addrs.v6addrs.dst)); 1506 keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1507 keys->ports.src = fl6->fl6_sport; 1508 keys->ports.dst = fl6->fl6_dport; 1509 keys->keyid.keyid = fl6->fl6_gre_key; 1510 keys->tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6); 1511 keys->basic.ip_proto = fl6->flowi6_proto; 1512 1513 return flow_hash_from_keys(keys); 1514 } 1515 EXPORT_SYMBOL(__get_hash_from_flowi6); 1516 1517 static const struct flow_dissector_key flow_keys_dissector_keys[] = { 1518 { 1519 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1520 .offset = offsetof(struct flow_keys, control), 1521 }, 1522 { 1523 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1524 .offset = offsetof(struct flow_keys, basic), 1525 }, 1526 { 1527 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1528 .offset = offsetof(struct flow_keys, addrs.v4addrs), 1529 }, 1530 { 1531 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1532 .offset = offsetof(struct flow_keys, addrs.v6addrs), 1533 }, 1534 { 1535 .key_id = FLOW_DISSECTOR_KEY_TIPC, 1536 .offset = offsetof(struct flow_keys, addrs.tipckey), 1537 }, 1538 { 1539 .key_id = FLOW_DISSECTOR_KEY_PORTS, 1540 .offset = offsetof(struct flow_keys, ports), 1541 }, 1542 { 1543 .key_id = FLOW_DISSECTOR_KEY_VLAN, 1544 .offset = offsetof(struct flow_keys, vlan), 1545 }, 1546 { 1547 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL, 1548 .offset = offsetof(struct flow_keys, tags), 1549 }, 1550 { 1551 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID, 1552 .offset = offsetof(struct flow_keys, keyid), 1553 }, 1554 }; 1555 1556 static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = { 1557 { 1558 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1559 .offset = offsetof(struct flow_keys, control), 1560 }, 1561 { 1562 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1563 .offset = offsetof(struct flow_keys, basic), 1564 }, 1565 { 1566 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1567 .offset = offsetof(struct flow_keys, addrs.v4addrs), 1568 }, 1569 { 1570 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1571 .offset = offsetof(struct flow_keys, addrs.v6addrs), 1572 }, 1573 { 1574 .key_id = FLOW_DISSECTOR_KEY_PORTS, 1575 .offset = offsetof(struct flow_keys, ports), 1576 }, 1577 }; 1578 1579 static const struct flow_dissector_key flow_keys_basic_dissector_keys[] = { 1580 { 1581 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1582 .offset = offsetof(struct flow_keys, control), 1583 }, 1584 { 1585 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1586 .offset = offsetof(struct flow_keys, basic), 1587 }, 1588 }; 1589 1590 struct flow_dissector flow_keys_dissector __read_mostly; 1591 EXPORT_SYMBOL(flow_keys_dissector); 1592 1593 struct flow_dissector flow_keys_basic_dissector __read_mostly; 1594 EXPORT_SYMBOL(flow_keys_basic_dissector); 1595 1596 static int __init init_default_flow_dissectors(void) 1597 { 1598 skb_flow_dissector_init(&flow_keys_dissector, 1599 flow_keys_dissector_keys, 1600 ARRAY_SIZE(flow_keys_dissector_keys)); 1601 skb_flow_dissector_init(&flow_keys_dissector_symmetric, 1602 flow_keys_dissector_symmetric_keys, 1603 ARRAY_SIZE(flow_keys_dissector_symmetric_keys)); 1604 skb_flow_dissector_init(&flow_keys_basic_dissector, 1605 flow_keys_basic_dissector_keys, 1606 ARRAY_SIZE(flow_keys_basic_dissector_keys)); 1607 return 0; 1608 } 1609 1610 core_initcall(init_default_flow_dissectors); 1611