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 bool __skb_flow_bpf_dissect(struct bpf_prog *prog, 687 const struct sk_buff *skb, 688 struct flow_dissector *flow_dissector, 689 struct bpf_flow_keys *flow_keys) 690 { 691 struct bpf_skb_data_end cb_saved; 692 struct bpf_skb_data_end *cb; 693 u32 result; 694 695 /* Note that even though the const qualifier is discarded 696 * throughout the execution of the BPF program, all changes(the 697 * control block) are reverted after the BPF program returns. 698 * Therefore, __skb_flow_dissect does not alter the skb. 699 */ 700 701 cb = (struct bpf_skb_data_end *)skb->cb; 702 703 /* Save Control Block */ 704 memcpy(&cb_saved, cb, sizeof(cb_saved)); 705 memset(cb, 0, sizeof(*cb)); 706 707 /* Pass parameters to the BPF program */ 708 memset(flow_keys, 0, sizeof(*flow_keys)); 709 cb->qdisc_cb.flow_keys = flow_keys; 710 flow_keys->n_proto = skb->protocol; 711 flow_keys->nhoff = skb_network_offset(skb); 712 flow_keys->thoff = flow_keys->nhoff; 713 714 bpf_compute_data_pointers((struct sk_buff *)skb); 715 result = BPF_PROG_RUN(prog, skb); 716 717 /* Restore state */ 718 memcpy(cb, &cb_saved, sizeof(cb_saved)); 719 720 flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, 721 skb_network_offset(skb), skb->len); 722 flow_keys->thoff = clamp_t(u16, flow_keys->thoff, 723 flow_keys->nhoff, skb->len); 724 725 return result == BPF_OK; 726 } 727 728 /** 729 * __skb_flow_dissect - extract the flow_keys struct and return it 730 * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified 731 * @flow_dissector: list of keys to dissect 732 * @target_container: target structure to put dissected values into 733 * @data: raw buffer pointer to the packet, if NULL use skb->data 734 * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol 735 * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb) 736 * @hlen: packet header length, if @data is NULL use skb_headlen(skb) 737 * 738 * The function will try to retrieve individual keys into target specified 739 * by flow_dissector from either the skbuff or a raw buffer specified by the 740 * rest parameters. 741 * 742 * Caller must take care of zeroing target container memory. 743 */ 744 bool __skb_flow_dissect(const struct sk_buff *skb, 745 struct flow_dissector *flow_dissector, 746 void *target_container, 747 void *data, __be16 proto, int nhoff, int hlen, 748 unsigned int flags) 749 { 750 struct flow_dissector_key_control *key_control; 751 struct flow_dissector_key_basic *key_basic; 752 struct flow_dissector_key_addrs *key_addrs; 753 struct flow_dissector_key_ports *key_ports; 754 struct flow_dissector_key_icmp *key_icmp; 755 struct flow_dissector_key_tags *key_tags; 756 struct flow_dissector_key_vlan *key_vlan; 757 enum flow_dissect_ret fdret; 758 enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX; 759 int num_hdrs = 0; 760 u8 ip_proto = 0; 761 bool ret; 762 763 if (!data) { 764 data = skb->data; 765 proto = skb_vlan_tag_present(skb) ? 766 skb->vlan_proto : skb->protocol; 767 nhoff = skb_network_offset(skb); 768 hlen = skb_headlen(skb); 769 #if IS_ENABLED(CONFIG_NET_DSA) 770 if (unlikely(skb->dev && netdev_uses_dsa(skb->dev))) { 771 const struct dsa_device_ops *ops; 772 int offset; 773 774 ops = skb->dev->dsa_ptr->tag_ops; 775 if (ops->flow_dissect && 776 !ops->flow_dissect(skb, &proto, &offset)) { 777 hlen -= offset; 778 nhoff += offset; 779 } 780 } 781 #endif 782 } 783 784 /* It is ensured by skb_flow_dissector_init() that control key will 785 * be always present. 786 */ 787 key_control = skb_flow_dissector_target(flow_dissector, 788 FLOW_DISSECTOR_KEY_CONTROL, 789 target_container); 790 791 /* It is ensured by skb_flow_dissector_init() that basic key will 792 * be always present. 793 */ 794 key_basic = skb_flow_dissector_target(flow_dissector, 795 FLOW_DISSECTOR_KEY_BASIC, 796 target_container); 797 798 if (skb) { 799 struct bpf_flow_keys flow_keys; 800 struct bpf_prog *attached = NULL; 801 802 rcu_read_lock(); 803 804 if (skb->dev) 805 attached = rcu_dereference(dev_net(skb->dev)->flow_dissector_prog); 806 else if (skb->sk) 807 attached = rcu_dereference(sock_net(skb->sk)->flow_dissector_prog); 808 else 809 WARN_ON_ONCE(1); 810 811 if (attached) { 812 ret = __skb_flow_bpf_dissect(attached, skb, 813 flow_dissector, 814 &flow_keys); 815 __skb_flow_bpf_to_target(&flow_keys, flow_dissector, 816 target_container); 817 rcu_read_unlock(); 818 return ret; 819 } 820 rcu_read_unlock(); 821 } 822 823 if (dissector_uses_key(flow_dissector, 824 FLOW_DISSECTOR_KEY_ETH_ADDRS)) { 825 struct ethhdr *eth = eth_hdr(skb); 826 struct flow_dissector_key_eth_addrs *key_eth_addrs; 827 828 key_eth_addrs = skb_flow_dissector_target(flow_dissector, 829 FLOW_DISSECTOR_KEY_ETH_ADDRS, 830 target_container); 831 memcpy(key_eth_addrs, ð->h_dest, sizeof(*key_eth_addrs)); 832 } 833 834 proto_again: 835 fdret = FLOW_DISSECT_RET_CONTINUE; 836 837 switch (proto) { 838 case htons(ETH_P_IP): { 839 const struct iphdr *iph; 840 struct iphdr _iph; 841 842 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 843 if (!iph || iph->ihl < 5) { 844 fdret = FLOW_DISSECT_RET_OUT_BAD; 845 break; 846 } 847 848 nhoff += iph->ihl * 4; 849 850 ip_proto = iph->protocol; 851 852 if (dissector_uses_key(flow_dissector, 853 FLOW_DISSECTOR_KEY_IPV4_ADDRS)) { 854 key_addrs = skb_flow_dissector_target(flow_dissector, 855 FLOW_DISSECTOR_KEY_IPV4_ADDRS, 856 target_container); 857 858 memcpy(&key_addrs->v4addrs, &iph->saddr, 859 sizeof(key_addrs->v4addrs)); 860 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; 861 } 862 863 if (ip_is_fragment(iph)) { 864 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 865 866 if (iph->frag_off & htons(IP_OFFSET)) { 867 fdret = FLOW_DISSECT_RET_OUT_GOOD; 868 break; 869 } else { 870 key_control->flags |= FLOW_DIS_FIRST_FRAG; 871 if (!(flags & 872 FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) { 873 fdret = FLOW_DISSECT_RET_OUT_GOOD; 874 break; 875 } 876 } 877 } 878 879 __skb_flow_dissect_ipv4(skb, flow_dissector, 880 target_container, data, iph); 881 882 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) { 883 fdret = FLOW_DISSECT_RET_OUT_GOOD; 884 break; 885 } 886 887 break; 888 } 889 case htons(ETH_P_IPV6): { 890 const struct ipv6hdr *iph; 891 struct ipv6hdr _iph; 892 893 iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); 894 if (!iph) { 895 fdret = FLOW_DISSECT_RET_OUT_BAD; 896 break; 897 } 898 899 ip_proto = iph->nexthdr; 900 nhoff += sizeof(struct ipv6hdr); 901 902 if (dissector_uses_key(flow_dissector, 903 FLOW_DISSECTOR_KEY_IPV6_ADDRS)) { 904 key_addrs = skb_flow_dissector_target(flow_dissector, 905 FLOW_DISSECTOR_KEY_IPV6_ADDRS, 906 target_container); 907 908 memcpy(&key_addrs->v6addrs, &iph->saddr, 909 sizeof(key_addrs->v6addrs)); 910 key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 911 } 912 913 if ((dissector_uses_key(flow_dissector, 914 FLOW_DISSECTOR_KEY_FLOW_LABEL) || 915 (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) && 916 ip6_flowlabel(iph)) { 917 __be32 flow_label = ip6_flowlabel(iph); 918 919 if (dissector_uses_key(flow_dissector, 920 FLOW_DISSECTOR_KEY_FLOW_LABEL)) { 921 key_tags = skb_flow_dissector_target(flow_dissector, 922 FLOW_DISSECTOR_KEY_FLOW_LABEL, 923 target_container); 924 key_tags->flow_label = ntohl(flow_label); 925 } 926 if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) { 927 fdret = FLOW_DISSECT_RET_OUT_GOOD; 928 break; 929 } 930 } 931 932 __skb_flow_dissect_ipv6(skb, flow_dissector, 933 target_container, data, iph); 934 935 if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) 936 fdret = FLOW_DISSECT_RET_OUT_GOOD; 937 938 break; 939 } 940 case htons(ETH_P_8021AD): 941 case htons(ETH_P_8021Q): { 942 const struct vlan_hdr *vlan = NULL; 943 struct vlan_hdr _vlan; 944 __be16 saved_vlan_tpid = proto; 945 946 if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX && 947 skb && skb_vlan_tag_present(skb)) { 948 proto = skb->protocol; 949 } else { 950 vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), 951 data, hlen, &_vlan); 952 if (!vlan) { 953 fdret = FLOW_DISSECT_RET_OUT_BAD; 954 break; 955 } 956 957 proto = vlan->h_vlan_encapsulated_proto; 958 nhoff += sizeof(*vlan); 959 } 960 961 if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX) { 962 dissector_vlan = FLOW_DISSECTOR_KEY_VLAN; 963 } else if (dissector_vlan == FLOW_DISSECTOR_KEY_VLAN) { 964 dissector_vlan = FLOW_DISSECTOR_KEY_CVLAN; 965 } else { 966 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 967 break; 968 } 969 970 if (dissector_uses_key(flow_dissector, dissector_vlan)) { 971 key_vlan = skb_flow_dissector_target(flow_dissector, 972 dissector_vlan, 973 target_container); 974 975 if (!vlan) { 976 key_vlan->vlan_id = skb_vlan_tag_get_id(skb); 977 key_vlan->vlan_priority = skb_vlan_tag_get_prio(skb); 978 } else { 979 key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) & 980 VLAN_VID_MASK; 981 key_vlan->vlan_priority = 982 (ntohs(vlan->h_vlan_TCI) & 983 VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; 984 } 985 key_vlan->vlan_tpid = saved_vlan_tpid; 986 } 987 988 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 989 break; 990 } 991 case htons(ETH_P_PPP_SES): { 992 struct { 993 struct pppoe_hdr hdr; 994 __be16 proto; 995 } *hdr, _hdr; 996 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr); 997 if (!hdr) { 998 fdret = FLOW_DISSECT_RET_OUT_BAD; 999 break; 1000 } 1001 1002 proto = hdr->proto; 1003 nhoff += PPPOE_SES_HLEN; 1004 switch (proto) { 1005 case htons(PPP_IP): 1006 proto = htons(ETH_P_IP); 1007 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1008 break; 1009 case htons(PPP_IPV6): 1010 proto = htons(ETH_P_IPV6); 1011 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1012 break; 1013 default: 1014 fdret = FLOW_DISSECT_RET_OUT_BAD; 1015 break; 1016 } 1017 break; 1018 } 1019 case htons(ETH_P_TIPC): { 1020 struct tipc_basic_hdr *hdr, _hdr; 1021 1022 hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), 1023 data, hlen, &_hdr); 1024 if (!hdr) { 1025 fdret = FLOW_DISSECT_RET_OUT_BAD; 1026 break; 1027 } 1028 1029 if (dissector_uses_key(flow_dissector, 1030 FLOW_DISSECTOR_KEY_TIPC)) { 1031 key_addrs = skb_flow_dissector_target(flow_dissector, 1032 FLOW_DISSECTOR_KEY_TIPC, 1033 target_container); 1034 key_addrs->tipckey.key = tipc_hdr_rps_key(hdr); 1035 key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC; 1036 } 1037 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1038 break; 1039 } 1040 1041 case htons(ETH_P_MPLS_UC): 1042 case htons(ETH_P_MPLS_MC): 1043 fdret = __skb_flow_dissect_mpls(skb, flow_dissector, 1044 target_container, data, 1045 nhoff, hlen); 1046 break; 1047 case htons(ETH_P_FCOE): 1048 if ((hlen - nhoff) < FCOE_HEADER_LEN) { 1049 fdret = FLOW_DISSECT_RET_OUT_BAD; 1050 break; 1051 } 1052 1053 nhoff += FCOE_HEADER_LEN; 1054 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1055 break; 1056 1057 case htons(ETH_P_ARP): 1058 case htons(ETH_P_RARP): 1059 fdret = __skb_flow_dissect_arp(skb, flow_dissector, 1060 target_container, data, 1061 nhoff, hlen); 1062 break; 1063 1064 case htons(ETH_P_BATMAN): 1065 fdret = __skb_flow_dissect_batadv(skb, key_control, data, 1066 &proto, &nhoff, hlen, flags); 1067 break; 1068 1069 default: 1070 fdret = FLOW_DISSECT_RET_OUT_BAD; 1071 break; 1072 } 1073 1074 /* Process result of proto processing */ 1075 switch (fdret) { 1076 case FLOW_DISSECT_RET_OUT_GOOD: 1077 goto out_good; 1078 case FLOW_DISSECT_RET_PROTO_AGAIN: 1079 if (skb_flow_dissect_allowed(&num_hdrs)) 1080 goto proto_again; 1081 goto out_good; 1082 case FLOW_DISSECT_RET_CONTINUE: 1083 case FLOW_DISSECT_RET_IPPROTO_AGAIN: 1084 break; 1085 case FLOW_DISSECT_RET_OUT_BAD: 1086 default: 1087 goto out_bad; 1088 } 1089 1090 ip_proto_again: 1091 fdret = FLOW_DISSECT_RET_CONTINUE; 1092 1093 switch (ip_proto) { 1094 case IPPROTO_GRE: 1095 fdret = __skb_flow_dissect_gre(skb, key_control, flow_dissector, 1096 target_container, data, 1097 &proto, &nhoff, &hlen, flags); 1098 break; 1099 1100 case NEXTHDR_HOP: 1101 case NEXTHDR_ROUTING: 1102 case NEXTHDR_DEST: { 1103 u8 _opthdr[2], *opthdr; 1104 1105 if (proto != htons(ETH_P_IPV6)) 1106 break; 1107 1108 opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr), 1109 data, hlen, &_opthdr); 1110 if (!opthdr) { 1111 fdret = FLOW_DISSECT_RET_OUT_BAD; 1112 break; 1113 } 1114 1115 ip_proto = opthdr[0]; 1116 nhoff += (opthdr[1] + 1) << 3; 1117 1118 fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN; 1119 break; 1120 } 1121 case NEXTHDR_FRAGMENT: { 1122 struct frag_hdr _fh, *fh; 1123 1124 if (proto != htons(ETH_P_IPV6)) 1125 break; 1126 1127 fh = __skb_header_pointer(skb, nhoff, sizeof(_fh), 1128 data, hlen, &_fh); 1129 1130 if (!fh) { 1131 fdret = FLOW_DISSECT_RET_OUT_BAD; 1132 break; 1133 } 1134 1135 key_control->flags |= FLOW_DIS_IS_FRAGMENT; 1136 1137 nhoff += sizeof(_fh); 1138 ip_proto = fh->nexthdr; 1139 1140 if (!(fh->frag_off & htons(IP6_OFFSET))) { 1141 key_control->flags |= FLOW_DIS_FIRST_FRAG; 1142 if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) { 1143 fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN; 1144 break; 1145 } 1146 } 1147 1148 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1149 break; 1150 } 1151 case IPPROTO_IPIP: 1152 proto = htons(ETH_P_IP); 1153 1154 key_control->flags |= FLOW_DIS_ENCAPSULATION; 1155 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) { 1156 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1157 break; 1158 } 1159 1160 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1161 break; 1162 1163 case IPPROTO_IPV6: 1164 proto = htons(ETH_P_IPV6); 1165 1166 key_control->flags |= FLOW_DIS_ENCAPSULATION; 1167 if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) { 1168 fdret = FLOW_DISSECT_RET_OUT_GOOD; 1169 break; 1170 } 1171 1172 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1173 break; 1174 1175 1176 case IPPROTO_MPLS: 1177 proto = htons(ETH_P_MPLS_UC); 1178 fdret = FLOW_DISSECT_RET_PROTO_AGAIN; 1179 break; 1180 1181 case IPPROTO_TCP: 1182 __skb_flow_dissect_tcp(skb, flow_dissector, target_container, 1183 data, nhoff, hlen); 1184 break; 1185 1186 default: 1187 break; 1188 } 1189 1190 if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS) && 1191 !(key_control->flags & FLOW_DIS_IS_FRAGMENT)) { 1192 key_ports = skb_flow_dissector_target(flow_dissector, 1193 FLOW_DISSECTOR_KEY_PORTS, 1194 target_container); 1195 key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto, 1196 data, hlen); 1197 } 1198 1199 if (dissector_uses_key(flow_dissector, 1200 FLOW_DISSECTOR_KEY_ICMP)) { 1201 key_icmp = skb_flow_dissector_target(flow_dissector, 1202 FLOW_DISSECTOR_KEY_ICMP, 1203 target_container); 1204 key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen); 1205 } 1206 1207 /* Process result of IP proto processing */ 1208 switch (fdret) { 1209 case FLOW_DISSECT_RET_PROTO_AGAIN: 1210 if (skb_flow_dissect_allowed(&num_hdrs)) 1211 goto proto_again; 1212 break; 1213 case FLOW_DISSECT_RET_IPPROTO_AGAIN: 1214 if (skb_flow_dissect_allowed(&num_hdrs)) 1215 goto ip_proto_again; 1216 break; 1217 case FLOW_DISSECT_RET_OUT_GOOD: 1218 case FLOW_DISSECT_RET_CONTINUE: 1219 break; 1220 case FLOW_DISSECT_RET_OUT_BAD: 1221 default: 1222 goto out_bad; 1223 } 1224 1225 out_good: 1226 ret = true; 1227 1228 out: 1229 key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen); 1230 key_basic->n_proto = proto; 1231 key_basic->ip_proto = ip_proto; 1232 1233 return ret; 1234 1235 out_bad: 1236 ret = false; 1237 goto out; 1238 } 1239 EXPORT_SYMBOL(__skb_flow_dissect); 1240 1241 static u32 hashrnd __read_mostly; 1242 static __always_inline void __flow_hash_secret_init(void) 1243 { 1244 net_get_random_once(&hashrnd, sizeof(hashrnd)); 1245 } 1246 1247 static __always_inline u32 __flow_hash_words(const u32 *words, u32 length, 1248 u32 keyval) 1249 { 1250 return jhash2(words, length, keyval); 1251 } 1252 1253 static inline const u32 *flow_keys_hash_start(const struct flow_keys *flow) 1254 { 1255 const void *p = flow; 1256 1257 BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % sizeof(u32)); 1258 return (const u32 *)(p + FLOW_KEYS_HASH_OFFSET); 1259 } 1260 1261 static inline size_t flow_keys_hash_length(const struct flow_keys *flow) 1262 { 1263 size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs); 1264 BUILD_BUG_ON((sizeof(*flow) - FLOW_KEYS_HASH_OFFSET) % sizeof(u32)); 1265 BUILD_BUG_ON(offsetof(typeof(*flow), addrs) != 1266 sizeof(*flow) - sizeof(flow->addrs)); 1267 1268 switch (flow->control.addr_type) { 1269 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1270 diff -= sizeof(flow->addrs.v4addrs); 1271 break; 1272 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1273 diff -= sizeof(flow->addrs.v6addrs); 1274 break; 1275 case FLOW_DISSECTOR_KEY_TIPC: 1276 diff -= sizeof(flow->addrs.tipckey); 1277 break; 1278 } 1279 return (sizeof(*flow) - diff) / sizeof(u32); 1280 } 1281 1282 __be32 flow_get_u32_src(const struct flow_keys *flow) 1283 { 1284 switch (flow->control.addr_type) { 1285 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1286 return flow->addrs.v4addrs.src; 1287 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1288 return (__force __be32)ipv6_addr_hash( 1289 &flow->addrs.v6addrs.src); 1290 case FLOW_DISSECTOR_KEY_TIPC: 1291 return flow->addrs.tipckey.key; 1292 default: 1293 return 0; 1294 } 1295 } 1296 EXPORT_SYMBOL(flow_get_u32_src); 1297 1298 __be32 flow_get_u32_dst(const struct flow_keys *flow) 1299 { 1300 switch (flow->control.addr_type) { 1301 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1302 return flow->addrs.v4addrs.dst; 1303 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1304 return (__force __be32)ipv6_addr_hash( 1305 &flow->addrs.v6addrs.dst); 1306 default: 1307 return 0; 1308 } 1309 } 1310 EXPORT_SYMBOL(flow_get_u32_dst); 1311 1312 static inline void __flow_hash_consistentify(struct flow_keys *keys) 1313 { 1314 int addr_diff, i; 1315 1316 switch (keys->control.addr_type) { 1317 case FLOW_DISSECTOR_KEY_IPV4_ADDRS: 1318 addr_diff = (__force u32)keys->addrs.v4addrs.dst - 1319 (__force u32)keys->addrs.v4addrs.src; 1320 if ((addr_diff < 0) || 1321 (addr_diff == 0 && 1322 ((__force u16)keys->ports.dst < 1323 (__force u16)keys->ports.src))) { 1324 swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst); 1325 swap(keys->ports.src, keys->ports.dst); 1326 } 1327 break; 1328 case FLOW_DISSECTOR_KEY_IPV6_ADDRS: 1329 addr_diff = memcmp(&keys->addrs.v6addrs.dst, 1330 &keys->addrs.v6addrs.src, 1331 sizeof(keys->addrs.v6addrs.dst)); 1332 if ((addr_diff < 0) || 1333 (addr_diff == 0 && 1334 ((__force u16)keys->ports.dst < 1335 (__force u16)keys->ports.src))) { 1336 for (i = 0; i < 4; i++) 1337 swap(keys->addrs.v6addrs.src.s6_addr32[i], 1338 keys->addrs.v6addrs.dst.s6_addr32[i]); 1339 swap(keys->ports.src, keys->ports.dst); 1340 } 1341 break; 1342 } 1343 } 1344 1345 static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval) 1346 { 1347 u32 hash; 1348 1349 __flow_hash_consistentify(keys); 1350 1351 hash = __flow_hash_words(flow_keys_hash_start(keys), 1352 flow_keys_hash_length(keys), keyval); 1353 if (!hash) 1354 hash = 1; 1355 1356 return hash; 1357 } 1358 1359 u32 flow_hash_from_keys(struct flow_keys *keys) 1360 { 1361 __flow_hash_secret_init(); 1362 return __flow_hash_from_keys(keys, hashrnd); 1363 } 1364 EXPORT_SYMBOL(flow_hash_from_keys); 1365 1366 static inline u32 ___skb_get_hash(const struct sk_buff *skb, 1367 struct flow_keys *keys, u32 keyval) 1368 { 1369 skb_flow_dissect_flow_keys(skb, keys, 1370 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 1371 1372 return __flow_hash_from_keys(keys, keyval); 1373 } 1374 1375 struct _flow_keys_digest_data { 1376 __be16 n_proto; 1377 u8 ip_proto; 1378 u8 padding; 1379 __be32 ports; 1380 __be32 src; 1381 __be32 dst; 1382 }; 1383 1384 void make_flow_keys_digest(struct flow_keys_digest *digest, 1385 const struct flow_keys *flow) 1386 { 1387 struct _flow_keys_digest_data *data = 1388 (struct _flow_keys_digest_data *)digest; 1389 1390 BUILD_BUG_ON(sizeof(*data) > sizeof(*digest)); 1391 1392 memset(digest, 0, sizeof(*digest)); 1393 1394 data->n_proto = flow->basic.n_proto; 1395 data->ip_proto = flow->basic.ip_proto; 1396 data->ports = flow->ports.ports; 1397 data->src = flow->addrs.v4addrs.src; 1398 data->dst = flow->addrs.v4addrs.dst; 1399 } 1400 EXPORT_SYMBOL(make_flow_keys_digest); 1401 1402 static struct flow_dissector flow_keys_dissector_symmetric __read_mostly; 1403 1404 u32 __skb_get_hash_symmetric(const struct sk_buff *skb) 1405 { 1406 struct flow_keys keys; 1407 1408 __flow_hash_secret_init(); 1409 1410 memset(&keys, 0, sizeof(keys)); 1411 __skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys, 1412 NULL, 0, 0, 0, 1413 FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); 1414 1415 return __flow_hash_from_keys(&keys, hashrnd); 1416 } 1417 EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric); 1418 1419 /** 1420 * __skb_get_hash: calculate a flow hash 1421 * @skb: sk_buff to calculate flow hash from 1422 * 1423 * This function calculates a flow hash based on src/dst addresses 1424 * and src/dst port numbers. Sets hash in skb to non-zero hash value 1425 * on success, zero indicates no valid hash. Also, sets l4_hash in skb 1426 * if hash is a canonical 4-tuple hash over transport ports. 1427 */ 1428 void __skb_get_hash(struct sk_buff *skb) 1429 { 1430 struct flow_keys keys; 1431 u32 hash; 1432 1433 __flow_hash_secret_init(); 1434 1435 hash = ___skb_get_hash(skb, &keys, hashrnd); 1436 1437 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys)); 1438 } 1439 EXPORT_SYMBOL(__skb_get_hash); 1440 1441 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb) 1442 { 1443 struct flow_keys keys; 1444 1445 return ___skb_get_hash(skb, &keys, perturb); 1446 } 1447 EXPORT_SYMBOL(skb_get_hash_perturb); 1448 1449 u32 __skb_get_poff(const struct sk_buff *skb, void *data, 1450 const struct flow_keys_basic *keys, int hlen) 1451 { 1452 u32 poff = keys->control.thoff; 1453 1454 /* skip L4 headers for fragments after the first */ 1455 if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) && 1456 !(keys->control.flags & FLOW_DIS_FIRST_FRAG)) 1457 return poff; 1458 1459 switch (keys->basic.ip_proto) { 1460 case IPPROTO_TCP: { 1461 /* access doff as u8 to avoid unaligned access */ 1462 const u8 *doff; 1463 u8 _doff; 1464 1465 doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff), 1466 data, hlen, &_doff); 1467 if (!doff) 1468 return poff; 1469 1470 poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2); 1471 break; 1472 } 1473 case IPPROTO_UDP: 1474 case IPPROTO_UDPLITE: 1475 poff += sizeof(struct udphdr); 1476 break; 1477 /* For the rest, we do not really care about header 1478 * extensions at this point for now. 1479 */ 1480 case IPPROTO_ICMP: 1481 poff += sizeof(struct icmphdr); 1482 break; 1483 case IPPROTO_ICMPV6: 1484 poff += sizeof(struct icmp6hdr); 1485 break; 1486 case IPPROTO_IGMP: 1487 poff += sizeof(struct igmphdr); 1488 break; 1489 case IPPROTO_DCCP: 1490 poff += sizeof(struct dccp_hdr); 1491 break; 1492 case IPPROTO_SCTP: 1493 poff += sizeof(struct sctphdr); 1494 break; 1495 } 1496 1497 return poff; 1498 } 1499 1500 /** 1501 * skb_get_poff - get the offset to the payload 1502 * @skb: sk_buff to get the payload offset from 1503 * 1504 * The function will get the offset to the payload as far as it could 1505 * be dissected. The main user is currently BPF, so that we can dynamically 1506 * truncate packets without needing to push actual payload to the user 1507 * space and can analyze headers only, instead. 1508 */ 1509 u32 skb_get_poff(const struct sk_buff *skb) 1510 { 1511 struct flow_keys_basic keys; 1512 1513 if (!skb_flow_dissect_flow_keys_basic(skb, &keys, NULL, 0, 0, 0, 0)) 1514 return 0; 1515 1516 return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb)); 1517 } 1518 1519 __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys) 1520 { 1521 memset(keys, 0, sizeof(*keys)); 1522 1523 memcpy(&keys->addrs.v6addrs.src, &fl6->saddr, 1524 sizeof(keys->addrs.v6addrs.src)); 1525 memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr, 1526 sizeof(keys->addrs.v6addrs.dst)); 1527 keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; 1528 keys->ports.src = fl6->fl6_sport; 1529 keys->ports.dst = fl6->fl6_dport; 1530 keys->keyid.keyid = fl6->fl6_gre_key; 1531 keys->tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6); 1532 keys->basic.ip_proto = fl6->flowi6_proto; 1533 1534 return flow_hash_from_keys(keys); 1535 } 1536 EXPORT_SYMBOL(__get_hash_from_flowi6); 1537 1538 static const struct flow_dissector_key flow_keys_dissector_keys[] = { 1539 { 1540 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1541 .offset = offsetof(struct flow_keys, control), 1542 }, 1543 { 1544 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1545 .offset = offsetof(struct flow_keys, basic), 1546 }, 1547 { 1548 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1549 .offset = offsetof(struct flow_keys, addrs.v4addrs), 1550 }, 1551 { 1552 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1553 .offset = offsetof(struct flow_keys, addrs.v6addrs), 1554 }, 1555 { 1556 .key_id = FLOW_DISSECTOR_KEY_TIPC, 1557 .offset = offsetof(struct flow_keys, addrs.tipckey), 1558 }, 1559 { 1560 .key_id = FLOW_DISSECTOR_KEY_PORTS, 1561 .offset = offsetof(struct flow_keys, ports), 1562 }, 1563 { 1564 .key_id = FLOW_DISSECTOR_KEY_VLAN, 1565 .offset = offsetof(struct flow_keys, vlan), 1566 }, 1567 { 1568 .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL, 1569 .offset = offsetof(struct flow_keys, tags), 1570 }, 1571 { 1572 .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID, 1573 .offset = offsetof(struct flow_keys, keyid), 1574 }, 1575 }; 1576 1577 static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = { 1578 { 1579 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1580 .offset = offsetof(struct flow_keys, control), 1581 }, 1582 { 1583 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1584 .offset = offsetof(struct flow_keys, basic), 1585 }, 1586 { 1587 .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, 1588 .offset = offsetof(struct flow_keys, addrs.v4addrs), 1589 }, 1590 { 1591 .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, 1592 .offset = offsetof(struct flow_keys, addrs.v6addrs), 1593 }, 1594 { 1595 .key_id = FLOW_DISSECTOR_KEY_PORTS, 1596 .offset = offsetof(struct flow_keys, ports), 1597 }, 1598 }; 1599 1600 static const struct flow_dissector_key flow_keys_basic_dissector_keys[] = { 1601 { 1602 .key_id = FLOW_DISSECTOR_KEY_CONTROL, 1603 .offset = offsetof(struct flow_keys, control), 1604 }, 1605 { 1606 .key_id = FLOW_DISSECTOR_KEY_BASIC, 1607 .offset = offsetof(struct flow_keys, basic), 1608 }, 1609 }; 1610 1611 struct flow_dissector flow_keys_dissector __read_mostly; 1612 EXPORT_SYMBOL(flow_keys_dissector); 1613 1614 struct flow_dissector flow_keys_basic_dissector __read_mostly; 1615 EXPORT_SYMBOL(flow_keys_basic_dissector); 1616 1617 static int __init init_default_flow_dissectors(void) 1618 { 1619 skb_flow_dissector_init(&flow_keys_dissector, 1620 flow_keys_dissector_keys, 1621 ARRAY_SIZE(flow_keys_dissector_keys)); 1622 skb_flow_dissector_init(&flow_keys_dissector_symmetric, 1623 flow_keys_dissector_symmetric_keys, 1624 ARRAY_SIZE(flow_keys_dissector_symmetric_keys)); 1625 skb_flow_dissector_init(&flow_keys_basic_dissector, 1626 flow_keys_basic_dissector_keys, 1627 ARRAY_SIZE(flow_keys_basic_dissector_keys)); 1628 return 0; 1629 } 1630 1631 core_initcall(init_default_flow_dissectors); 1632