1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * The User Datagram Protocol (UDP). 8 * 9 * Authors: Ross Biro 10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 11 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 12 * Alan Cox, <alan@lxorguk.ukuu.org.uk> 13 * Hirokazu Takahashi, <taka@valinux.co.jp> 14 * 15 * Fixes: 16 * Alan Cox : verify_area() calls 17 * Alan Cox : stopped close while in use off icmp 18 * messages. Not a fix but a botch that 19 * for udp at least is 'valid'. 20 * Alan Cox : Fixed icmp handling properly 21 * Alan Cox : Correct error for oversized datagrams 22 * Alan Cox : Tidied select() semantics. 23 * Alan Cox : udp_err() fixed properly, also now 24 * select and read wake correctly on errors 25 * Alan Cox : udp_send verify_area moved to avoid mem leak 26 * Alan Cox : UDP can count its memory 27 * Alan Cox : send to an unknown connection causes 28 * an ECONNREFUSED off the icmp, but 29 * does NOT close. 30 * Alan Cox : Switched to new sk_buff handlers. No more backlog! 31 * Alan Cox : Using generic datagram code. Even smaller and the PEEK 32 * bug no longer crashes it. 33 * Fred Van Kempen : Net2e support for sk->broadcast. 34 * Alan Cox : Uses skb_free_datagram 35 * Alan Cox : Added get/set sockopt support. 36 * Alan Cox : Broadcasting without option set returns EACCES. 37 * Alan Cox : No wakeup calls. Instead we now use the callbacks. 38 * Alan Cox : Use ip_tos and ip_ttl 39 * Alan Cox : SNMP Mibs 40 * Alan Cox : MSG_DONTROUTE, and 0.0.0.0 support. 41 * Matt Dillon : UDP length checks. 42 * Alan Cox : Smarter af_inet used properly. 43 * Alan Cox : Use new kernel side addressing. 44 * Alan Cox : Incorrect return on truncated datagram receive. 45 * Arnt Gulbrandsen : New udp_send and stuff 46 * Alan Cox : Cache last socket 47 * Alan Cox : Route cache 48 * Jon Peatfield : Minor efficiency fix to sendto(). 49 * Mike Shaver : RFC1122 checks. 50 * Alan Cox : Nonblocking error fix. 51 * Willy Konynenberg : Transparent proxying support. 52 * Mike McLagan : Routing by source 53 * David S. Miller : New socket lookup architecture. 54 * Last socket cache retained as it 55 * does have a high hit rate. 56 * Olaf Kirch : Don't linearise iovec on sendmsg. 57 * Andi Kleen : Some cleanups, cache destination entry 58 * for connect. 59 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 60 * Melvin Smith : Check msg_name not msg_namelen in sendto(), 61 * return ENOTCONN for unconnected sockets (POSIX) 62 * Janos Farkas : don't deliver multi/broadcasts to a different 63 * bound-to-device socket 64 * Hirokazu Takahashi : HW checksumming for outgoing UDP 65 * datagrams. 66 * Hirokazu Takahashi : sendfile() on UDP works now. 67 * Arnaldo C. Melo : convert /proc/net/udp to seq_file 68 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which 69 * Alexey Kuznetsov: allow both IPv4 and IPv6 sockets to bind 70 * a single port at the same time. 71 * Derek Atkins <derek@ihtfp.com>: Add Encapulation Support 72 * James Chapman : Add L2TP encapsulation type. 73 */ 74 75 #define pr_fmt(fmt) "UDP: " fmt 76 77 #include <linux/bpf-cgroup.h> 78 #include <linux/uaccess.h> 79 #include <asm/ioctls.h> 80 #include <linux/memblock.h> 81 #include <linux/highmem.h> 82 #include <linux/types.h> 83 #include <linux/fcntl.h> 84 #include <linux/module.h> 85 #include <linux/socket.h> 86 #include <linux/sockios.h> 87 #include <linux/igmp.h> 88 #include <linux/inetdevice.h> 89 #include <linux/in.h> 90 #include <linux/errno.h> 91 #include <linux/timer.h> 92 #include <linux/mm.h> 93 #include <linux/inet.h> 94 #include <linux/netdevice.h> 95 #include <linux/slab.h> 96 #include <net/tcp_states.h> 97 #include <linux/skbuff.h> 98 #include <linux/proc_fs.h> 99 #include <linux/seq_file.h> 100 #include <net/net_namespace.h> 101 #include <net/icmp.h> 102 #include <net/inet_hashtables.h> 103 #include <net/ip_tunnels.h> 104 #include <net/route.h> 105 #include <net/checksum.h> 106 #include <net/gso.h> 107 #include <net/xfrm.h> 108 #include <trace/events/udp.h> 109 #include <linux/static_key.h> 110 #include <linux/btf_ids.h> 111 #include <trace/events/skb.h> 112 #include <net/busy_poll.h> 113 #include "udp_impl.h" 114 #include <net/sock_reuseport.h> 115 #include <net/addrconf.h> 116 #include <net/udp_tunnel.h> 117 #include <net/gro.h> 118 #if IS_ENABLED(CONFIG_IPV6) 119 #include <net/ipv6_stubs.h> 120 #endif 121 122 struct udp_table udp_table __read_mostly; 123 EXPORT_SYMBOL(udp_table); 124 125 long sysctl_udp_mem[3] __read_mostly; 126 EXPORT_SYMBOL(sysctl_udp_mem); 127 128 atomic_long_t udp_memory_allocated ____cacheline_aligned_in_smp; 129 EXPORT_SYMBOL(udp_memory_allocated); 130 DEFINE_PER_CPU(int, udp_memory_per_cpu_fw_alloc); 131 EXPORT_PER_CPU_SYMBOL_GPL(udp_memory_per_cpu_fw_alloc); 132 133 #define MAX_UDP_PORTS 65536 134 #define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN_PERNET) 135 136 static struct udp_table *udp_get_table_prot(struct sock *sk) 137 { 138 return sk->sk_prot->h.udp_table ? : sock_net(sk)->ipv4.udp_table; 139 } 140 141 static int udp_lib_lport_inuse(struct net *net, __u16 num, 142 const struct udp_hslot *hslot, 143 unsigned long *bitmap, 144 struct sock *sk, unsigned int log) 145 { 146 struct sock *sk2; 147 kuid_t uid = sock_i_uid(sk); 148 149 sk_for_each(sk2, &hslot->head) { 150 if (net_eq(sock_net(sk2), net) && 151 sk2 != sk && 152 (bitmap || udp_sk(sk2)->udp_port_hash == num) && 153 (!sk2->sk_reuse || !sk->sk_reuse) && 154 (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if || 155 sk2->sk_bound_dev_if == sk->sk_bound_dev_if) && 156 inet_rcv_saddr_equal(sk, sk2, true)) { 157 if (sk2->sk_reuseport && sk->sk_reuseport && 158 !rcu_access_pointer(sk->sk_reuseport_cb) && 159 uid_eq(uid, sock_i_uid(sk2))) { 160 if (!bitmap) 161 return 0; 162 } else { 163 if (!bitmap) 164 return 1; 165 __set_bit(udp_sk(sk2)->udp_port_hash >> log, 166 bitmap); 167 } 168 } 169 } 170 return 0; 171 } 172 173 /* 174 * Note: we still hold spinlock of primary hash chain, so no other writer 175 * can insert/delete a socket with local_port == num 176 */ 177 static int udp_lib_lport_inuse2(struct net *net, __u16 num, 178 struct udp_hslot *hslot2, 179 struct sock *sk) 180 { 181 struct sock *sk2; 182 kuid_t uid = sock_i_uid(sk); 183 int res = 0; 184 185 spin_lock(&hslot2->lock); 186 udp_portaddr_for_each_entry(sk2, &hslot2->head) { 187 if (net_eq(sock_net(sk2), net) && 188 sk2 != sk && 189 (udp_sk(sk2)->udp_port_hash == num) && 190 (!sk2->sk_reuse || !sk->sk_reuse) && 191 (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if || 192 sk2->sk_bound_dev_if == sk->sk_bound_dev_if) && 193 inet_rcv_saddr_equal(sk, sk2, true)) { 194 if (sk2->sk_reuseport && sk->sk_reuseport && 195 !rcu_access_pointer(sk->sk_reuseport_cb) && 196 uid_eq(uid, sock_i_uid(sk2))) { 197 res = 0; 198 } else { 199 res = 1; 200 } 201 break; 202 } 203 } 204 spin_unlock(&hslot2->lock); 205 return res; 206 } 207 208 static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot) 209 { 210 struct net *net = sock_net(sk); 211 kuid_t uid = sock_i_uid(sk); 212 struct sock *sk2; 213 214 sk_for_each(sk2, &hslot->head) { 215 if (net_eq(sock_net(sk2), net) && 216 sk2 != sk && 217 sk2->sk_family == sk->sk_family && 218 ipv6_only_sock(sk2) == ipv6_only_sock(sk) && 219 (udp_sk(sk2)->udp_port_hash == udp_sk(sk)->udp_port_hash) && 220 (sk2->sk_bound_dev_if == sk->sk_bound_dev_if) && 221 sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) && 222 inet_rcv_saddr_equal(sk, sk2, false)) { 223 return reuseport_add_sock(sk, sk2, 224 inet_rcv_saddr_any(sk)); 225 } 226 } 227 228 return reuseport_alloc(sk, inet_rcv_saddr_any(sk)); 229 } 230 231 /** 232 * udp_lib_get_port - UDP/-Lite port lookup for IPv4 and IPv6 233 * 234 * @sk: socket struct in question 235 * @snum: port number to look up 236 * @hash2_nulladdr: AF-dependent hash value in secondary hash chains, 237 * with NULL address 238 */ 239 int udp_lib_get_port(struct sock *sk, unsigned short snum, 240 unsigned int hash2_nulladdr) 241 { 242 struct udp_table *udptable = udp_get_table_prot(sk); 243 struct udp_hslot *hslot, *hslot2; 244 struct net *net = sock_net(sk); 245 int error = -EADDRINUSE; 246 247 if (!snum) { 248 DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN); 249 unsigned short first, last; 250 int low, high, remaining; 251 unsigned int rand; 252 253 inet_sk_get_local_port_range(sk, &low, &high); 254 remaining = (high - low) + 1; 255 256 rand = get_random_u32(); 257 first = reciprocal_scale(rand, remaining) + low; 258 /* 259 * force rand to be an odd multiple of UDP_HTABLE_SIZE 260 */ 261 rand = (rand | 1) * (udptable->mask + 1); 262 last = first + udptable->mask + 1; 263 do { 264 hslot = udp_hashslot(udptable, net, first); 265 bitmap_zero(bitmap, PORTS_PER_CHAIN); 266 spin_lock_bh(&hslot->lock); 267 udp_lib_lport_inuse(net, snum, hslot, bitmap, sk, 268 udptable->log); 269 270 snum = first; 271 /* 272 * Iterate on all possible values of snum for this hash. 273 * Using steps of an odd multiple of UDP_HTABLE_SIZE 274 * give us randomization and full range coverage. 275 */ 276 do { 277 if (low <= snum && snum <= high && 278 !test_bit(snum >> udptable->log, bitmap) && 279 !inet_is_local_reserved_port(net, snum)) 280 goto found; 281 snum += rand; 282 } while (snum != first); 283 spin_unlock_bh(&hslot->lock); 284 cond_resched(); 285 } while (++first != last); 286 goto fail; 287 } else { 288 hslot = udp_hashslot(udptable, net, snum); 289 spin_lock_bh(&hslot->lock); 290 if (hslot->count > 10) { 291 int exist; 292 unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum; 293 294 slot2 &= udptable->mask; 295 hash2_nulladdr &= udptable->mask; 296 297 hslot2 = udp_hashslot2(udptable, slot2); 298 if (hslot->count < hslot2->count) 299 goto scan_primary_hash; 300 301 exist = udp_lib_lport_inuse2(net, snum, hslot2, sk); 302 if (!exist && (hash2_nulladdr != slot2)) { 303 hslot2 = udp_hashslot2(udptable, hash2_nulladdr); 304 exist = udp_lib_lport_inuse2(net, snum, hslot2, 305 sk); 306 } 307 if (exist) 308 goto fail_unlock; 309 else 310 goto found; 311 } 312 scan_primary_hash: 313 if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk, 0)) 314 goto fail_unlock; 315 } 316 found: 317 inet_sk(sk)->inet_num = snum; 318 udp_sk(sk)->udp_port_hash = snum; 319 udp_sk(sk)->udp_portaddr_hash ^= snum; 320 if (sk_unhashed(sk)) { 321 if (sk->sk_reuseport && 322 udp_reuseport_add_sock(sk, hslot)) { 323 inet_sk(sk)->inet_num = 0; 324 udp_sk(sk)->udp_port_hash = 0; 325 udp_sk(sk)->udp_portaddr_hash ^= snum; 326 goto fail_unlock; 327 } 328 329 sock_set_flag(sk, SOCK_RCU_FREE); 330 331 sk_add_node_rcu(sk, &hslot->head); 332 hslot->count++; 333 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 334 335 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash); 336 spin_lock(&hslot2->lock); 337 if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport && 338 sk->sk_family == AF_INET6) 339 hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node, 340 &hslot2->head); 341 else 342 hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node, 343 &hslot2->head); 344 hslot2->count++; 345 spin_unlock(&hslot2->lock); 346 } 347 348 error = 0; 349 fail_unlock: 350 spin_unlock_bh(&hslot->lock); 351 fail: 352 return error; 353 } 354 EXPORT_SYMBOL(udp_lib_get_port); 355 356 int udp_v4_get_port(struct sock *sk, unsigned short snum) 357 { 358 unsigned int hash2_nulladdr = 359 ipv4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum); 360 unsigned int hash2_partial = 361 ipv4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0); 362 363 /* precompute partial secondary hash */ 364 udp_sk(sk)->udp_portaddr_hash = hash2_partial; 365 return udp_lib_get_port(sk, snum, hash2_nulladdr); 366 } 367 368 static int compute_score(struct sock *sk, struct net *net, 369 __be32 saddr, __be16 sport, 370 __be32 daddr, unsigned short hnum, 371 int dif, int sdif) 372 { 373 int score; 374 struct inet_sock *inet; 375 bool dev_match; 376 377 if (!net_eq(sock_net(sk), net) || 378 udp_sk(sk)->udp_port_hash != hnum || 379 ipv6_only_sock(sk)) 380 return -1; 381 382 if (sk->sk_rcv_saddr != daddr) 383 return -1; 384 385 score = (sk->sk_family == PF_INET) ? 2 : 1; 386 387 inet = inet_sk(sk); 388 if (inet->inet_daddr) { 389 if (inet->inet_daddr != saddr) 390 return -1; 391 score += 4; 392 } 393 394 if (inet->inet_dport) { 395 if (inet->inet_dport != sport) 396 return -1; 397 score += 4; 398 } 399 400 dev_match = udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, 401 dif, sdif); 402 if (!dev_match) 403 return -1; 404 if (sk->sk_bound_dev_if) 405 score += 4; 406 407 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id()) 408 score++; 409 return score; 410 } 411 412 INDIRECT_CALLABLE_SCOPE 413 u32 udp_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport, 414 const __be32 faddr, const __be16 fport) 415 { 416 net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret)); 417 418 return __inet_ehashfn(laddr, lport, faddr, fport, 419 udp_ehash_secret + net_hash_mix(net)); 420 } 421 422 /* called with rcu_read_lock() */ 423 static struct sock *udp4_lib_lookup2(struct net *net, 424 __be32 saddr, __be16 sport, 425 __be32 daddr, unsigned int hnum, 426 int dif, int sdif, 427 struct udp_hslot *hslot2, 428 struct sk_buff *skb) 429 { 430 struct sock *sk, *result; 431 int score, badness; 432 bool need_rescore; 433 434 result = NULL; 435 badness = 0; 436 udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) { 437 need_rescore = false; 438 rescore: 439 score = compute_score(need_rescore ? result : sk, net, saddr, 440 sport, daddr, hnum, dif, sdif); 441 if (score > badness) { 442 badness = score; 443 444 if (need_rescore) 445 continue; 446 447 if (sk->sk_state == TCP_ESTABLISHED) { 448 result = sk; 449 continue; 450 } 451 452 result = inet_lookup_reuseport(net, sk, skb, sizeof(struct udphdr), 453 saddr, sport, daddr, hnum, udp_ehashfn); 454 if (!result) { 455 result = sk; 456 continue; 457 } 458 459 /* Fall back to scoring if group has connections */ 460 if (!reuseport_has_conns(sk)) 461 return result; 462 463 /* Reuseport logic returned an error, keep original score. */ 464 if (IS_ERR(result)) 465 continue; 466 467 /* compute_score is too long of a function to be 468 * inlined, and calling it again here yields 469 * measureable overhead for some 470 * workloads. Work around it by jumping 471 * backwards to rescore 'result'. 472 */ 473 need_rescore = true; 474 goto rescore; 475 } 476 } 477 return result; 478 } 479 480 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try 481 * harder than this. -DaveM 482 */ 483 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, 484 __be16 sport, __be32 daddr, __be16 dport, int dif, 485 int sdif, struct udp_table *udptable, struct sk_buff *skb) 486 { 487 unsigned short hnum = ntohs(dport); 488 unsigned int hash2, slot2; 489 struct udp_hslot *hslot2; 490 struct sock *result, *sk; 491 492 hash2 = ipv4_portaddr_hash(net, daddr, hnum); 493 slot2 = hash2 & udptable->mask; 494 hslot2 = &udptable->hash2[slot2]; 495 496 /* Lookup connected or non-wildcard socket */ 497 result = udp4_lib_lookup2(net, saddr, sport, 498 daddr, hnum, dif, sdif, 499 hslot2, skb); 500 if (!IS_ERR_OR_NULL(result) && result->sk_state == TCP_ESTABLISHED) 501 goto done; 502 503 /* Lookup redirect from BPF */ 504 if (static_branch_unlikely(&bpf_sk_lookup_enabled) && 505 udptable == net->ipv4.udp_table) { 506 sk = inet_lookup_run_sk_lookup(net, IPPROTO_UDP, skb, sizeof(struct udphdr), 507 saddr, sport, daddr, hnum, dif, 508 udp_ehashfn); 509 if (sk) { 510 result = sk; 511 goto done; 512 } 513 } 514 515 /* Got non-wildcard socket or error on first lookup */ 516 if (result) 517 goto done; 518 519 /* Lookup wildcard sockets */ 520 hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum); 521 slot2 = hash2 & udptable->mask; 522 hslot2 = &udptable->hash2[slot2]; 523 524 result = udp4_lib_lookup2(net, saddr, sport, 525 htonl(INADDR_ANY), hnum, dif, sdif, 526 hslot2, skb); 527 done: 528 if (IS_ERR(result)) 529 return NULL; 530 return result; 531 } 532 EXPORT_SYMBOL_GPL(__udp4_lib_lookup); 533 534 static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb, 535 __be16 sport, __be16 dport, 536 struct udp_table *udptable) 537 { 538 const struct iphdr *iph = ip_hdr(skb); 539 540 return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport, 541 iph->daddr, dport, inet_iif(skb), 542 inet_sdif(skb), udptable, skb); 543 } 544 545 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb, 546 __be16 sport, __be16 dport) 547 { 548 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation]; 549 const struct iphdr *iph = (struct iphdr *)(skb->data + offset); 550 struct net *net = dev_net(skb->dev); 551 int iif, sdif; 552 553 inet_get_iif_sdif(skb, &iif, &sdif); 554 555 return __udp4_lib_lookup(net, iph->saddr, sport, 556 iph->daddr, dport, iif, 557 sdif, net->ipv4.udp_table, NULL); 558 } 559 560 /* Must be called under rcu_read_lock(). 561 * Does increment socket refcount. 562 */ 563 #if IS_ENABLED(CONFIG_NF_TPROXY_IPV4) || IS_ENABLED(CONFIG_NF_SOCKET_IPV4) 564 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 565 __be32 daddr, __be16 dport, int dif) 566 { 567 struct sock *sk; 568 569 sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport, 570 dif, 0, net->ipv4.udp_table, NULL); 571 if (sk && !refcount_inc_not_zero(&sk->sk_refcnt)) 572 sk = NULL; 573 return sk; 574 } 575 EXPORT_SYMBOL_GPL(udp4_lib_lookup); 576 #endif 577 578 static inline bool __udp_is_mcast_sock(struct net *net, const struct sock *sk, 579 __be16 loc_port, __be32 loc_addr, 580 __be16 rmt_port, __be32 rmt_addr, 581 int dif, int sdif, unsigned short hnum) 582 { 583 const struct inet_sock *inet = inet_sk(sk); 584 585 if (!net_eq(sock_net(sk), net) || 586 udp_sk(sk)->udp_port_hash != hnum || 587 (inet->inet_daddr && inet->inet_daddr != rmt_addr) || 588 (inet->inet_dport != rmt_port && inet->inet_dport) || 589 (inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) || 590 ipv6_only_sock(sk) || 591 !udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif)) 592 return false; 593 if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif, sdif)) 594 return false; 595 return true; 596 } 597 598 DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key); 599 EXPORT_SYMBOL(udp_encap_needed_key); 600 601 #if IS_ENABLED(CONFIG_IPV6) 602 DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key); 603 EXPORT_SYMBOL(udpv6_encap_needed_key); 604 #endif 605 606 void udp_encap_enable(void) 607 { 608 static_branch_inc(&udp_encap_needed_key); 609 } 610 EXPORT_SYMBOL(udp_encap_enable); 611 612 void udp_encap_disable(void) 613 { 614 static_branch_dec(&udp_encap_needed_key); 615 } 616 EXPORT_SYMBOL(udp_encap_disable); 617 618 /* Handler for tunnels with arbitrary destination ports: no socket lookup, go 619 * through error handlers in encapsulations looking for a match. 620 */ 621 static int __udp4_lib_err_encap_no_sk(struct sk_buff *skb, u32 info) 622 { 623 int i; 624 625 for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) { 626 int (*handler)(struct sk_buff *skb, u32 info); 627 const struct ip_tunnel_encap_ops *encap; 628 629 encap = rcu_dereference(iptun_encaps[i]); 630 if (!encap) 631 continue; 632 handler = encap->err_handler; 633 if (handler && !handler(skb, info)) 634 return 0; 635 } 636 637 return -ENOENT; 638 } 639 640 /* Try to match ICMP errors to UDP tunnels by looking up a socket without 641 * reversing source and destination port: this will match tunnels that force the 642 * same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that 643 * lwtunnels might actually break this assumption by being configured with 644 * different destination ports on endpoints, in this case we won't be able to 645 * trace ICMP messages back to them. 646 * 647 * If this doesn't match any socket, probe tunnels with arbitrary destination 648 * ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port 649 * we've sent packets to won't necessarily match the local destination port. 650 * 651 * Then ask the tunnel implementation to match the error against a valid 652 * association. 653 * 654 * Return an error if we can't find a match, the socket if we need further 655 * processing, zero otherwise. 656 */ 657 static struct sock *__udp4_lib_err_encap(struct net *net, 658 const struct iphdr *iph, 659 struct udphdr *uh, 660 struct udp_table *udptable, 661 struct sock *sk, 662 struct sk_buff *skb, u32 info) 663 { 664 int (*lookup)(struct sock *sk, struct sk_buff *skb); 665 int network_offset, transport_offset; 666 struct udp_sock *up; 667 668 network_offset = skb_network_offset(skb); 669 transport_offset = skb_transport_offset(skb); 670 671 /* Network header needs to point to the outer IPv4 header inside ICMP */ 672 skb_reset_network_header(skb); 673 674 /* Transport header needs to point to the UDP header */ 675 skb_set_transport_header(skb, iph->ihl << 2); 676 677 if (sk) { 678 up = udp_sk(sk); 679 680 lookup = READ_ONCE(up->encap_err_lookup); 681 if (lookup && lookup(sk, skb)) 682 sk = NULL; 683 684 goto out; 685 } 686 687 sk = __udp4_lib_lookup(net, iph->daddr, uh->source, 688 iph->saddr, uh->dest, skb->dev->ifindex, 0, 689 udptable, NULL); 690 if (sk) { 691 up = udp_sk(sk); 692 693 lookup = READ_ONCE(up->encap_err_lookup); 694 if (!lookup || lookup(sk, skb)) 695 sk = NULL; 696 } 697 698 out: 699 if (!sk) 700 sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info)); 701 702 skb_set_transport_header(skb, transport_offset); 703 skb_set_network_header(skb, network_offset); 704 705 return sk; 706 } 707 708 /* 709 * This routine is called by the ICMP module when it gets some 710 * sort of error condition. If err < 0 then the socket should 711 * be closed and the error returned to the user. If err > 0 712 * it's just the icmp type << 8 | icmp code. 713 * Header points to the ip header of the error packet. We move 714 * on past this. Then (as it used to claim before adjustment) 715 * header points to the first 8 bytes of the udp header. We need 716 * to find the appropriate port. 717 */ 718 719 int __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable) 720 { 721 struct inet_sock *inet; 722 const struct iphdr *iph = (const struct iphdr *)skb->data; 723 struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2)); 724 const int type = icmp_hdr(skb)->type; 725 const int code = icmp_hdr(skb)->code; 726 bool tunnel = false; 727 struct sock *sk; 728 int harderr; 729 int err; 730 struct net *net = dev_net(skb->dev); 731 732 sk = __udp4_lib_lookup(net, iph->daddr, uh->dest, 733 iph->saddr, uh->source, skb->dev->ifindex, 734 inet_sdif(skb), udptable, NULL); 735 736 if (!sk || READ_ONCE(udp_sk(sk)->encap_type)) { 737 /* No socket for error: try tunnels before discarding */ 738 if (static_branch_unlikely(&udp_encap_needed_key)) { 739 sk = __udp4_lib_err_encap(net, iph, uh, udptable, sk, skb, 740 info); 741 if (!sk) 742 return 0; 743 } else 744 sk = ERR_PTR(-ENOENT); 745 746 if (IS_ERR(sk)) { 747 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); 748 return PTR_ERR(sk); 749 } 750 751 tunnel = true; 752 } 753 754 err = 0; 755 harderr = 0; 756 inet = inet_sk(sk); 757 758 switch (type) { 759 default: 760 case ICMP_TIME_EXCEEDED: 761 err = EHOSTUNREACH; 762 break; 763 case ICMP_SOURCE_QUENCH: 764 goto out; 765 case ICMP_PARAMETERPROB: 766 err = EPROTO; 767 harderr = 1; 768 break; 769 case ICMP_DEST_UNREACH: 770 if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */ 771 ipv4_sk_update_pmtu(skb, sk, info); 772 if (READ_ONCE(inet->pmtudisc) != IP_PMTUDISC_DONT) { 773 err = EMSGSIZE; 774 harderr = 1; 775 break; 776 } 777 goto out; 778 } 779 err = EHOSTUNREACH; 780 if (code <= NR_ICMP_UNREACH) { 781 harderr = icmp_err_convert[code].fatal; 782 err = icmp_err_convert[code].errno; 783 } 784 break; 785 case ICMP_REDIRECT: 786 ipv4_sk_redirect(skb, sk); 787 goto out; 788 } 789 790 /* 791 * RFC1122: OK. Passes ICMP errors back to application, as per 792 * 4.1.3.3. 793 */ 794 if (tunnel) { 795 /* ...not for tunnels though: we don't have a sending socket */ 796 if (udp_sk(sk)->encap_err_rcv) 797 udp_sk(sk)->encap_err_rcv(sk, skb, err, uh->dest, info, 798 (u8 *)(uh+1)); 799 goto out; 800 } 801 if (!inet_test_bit(RECVERR, sk)) { 802 if (!harderr || sk->sk_state != TCP_ESTABLISHED) 803 goto out; 804 } else 805 ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1)); 806 807 sk->sk_err = err; 808 sk_error_report(sk); 809 out: 810 return 0; 811 } 812 813 int udp_err(struct sk_buff *skb, u32 info) 814 { 815 return __udp4_lib_err(skb, info, dev_net(skb->dev)->ipv4.udp_table); 816 } 817 818 /* 819 * Throw away all pending data and cancel the corking. Socket is locked. 820 */ 821 void udp_flush_pending_frames(struct sock *sk) 822 { 823 struct udp_sock *up = udp_sk(sk); 824 825 if (up->pending) { 826 up->len = 0; 827 WRITE_ONCE(up->pending, 0); 828 ip_flush_pending_frames(sk); 829 } 830 } 831 EXPORT_SYMBOL(udp_flush_pending_frames); 832 833 /** 834 * udp4_hwcsum - handle outgoing HW checksumming 835 * @skb: sk_buff containing the filled-in UDP header 836 * (checksum field must be zeroed out) 837 * @src: source IP address 838 * @dst: destination IP address 839 */ 840 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst) 841 { 842 struct udphdr *uh = udp_hdr(skb); 843 int offset = skb_transport_offset(skb); 844 int len = skb->len - offset; 845 int hlen = len; 846 __wsum csum = 0; 847 848 if (!skb_has_frag_list(skb)) { 849 /* 850 * Only one fragment on the socket. 851 */ 852 skb->csum_start = skb_transport_header(skb) - skb->head; 853 skb->csum_offset = offsetof(struct udphdr, check); 854 uh->check = ~csum_tcpudp_magic(src, dst, len, 855 IPPROTO_UDP, 0); 856 } else { 857 struct sk_buff *frags; 858 859 /* 860 * HW-checksum won't work as there are two or more 861 * fragments on the socket so that all csums of sk_buffs 862 * should be together 863 */ 864 skb_walk_frags(skb, frags) { 865 csum = csum_add(csum, frags->csum); 866 hlen -= frags->len; 867 } 868 869 csum = skb_checksum(skb, offset, hlen, csum); 870 skb->ip_summed = CHECKSUM_NONE; 871 872 uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum); 873 if (uh->check == 0) 874 uh->check = CSUM_MANGLED_0; 875 } 876 } 877 EXPORT_SYMBOL_GPL(udp4_hwcsum); 878 879 /* Function to set UDP checksum for an IPv4 UDP packet. This is intended 880 * for the simple case like when setting the checksum for a UDP tunnel. 881 */ 882 void udp_set_csum(bool nocheck, struct sk_buff *skb, 883 __be32 saddr, __be32 daddr, int len) 884 { 885 struct udphdr *uh = udp_hdr(skb); 886 887 if (nocheck) { 888 uh->check = 0; 889 } else if (skb_is_gso(skb)) { 890 uh->check = ~udp_v4_check(len, saddr, daddr, 0); 891 } else if (skb->ip_summed == CHECKSUM_PARTIAL) { 892 uh->check = 0; 893 uh->check = udp_v4_check(len, saddr, daddr, lco_csum(skb)); 894 if (uh->check == 0) 895 uh->check = CSUM_MANGLED_0; 896 } else { 897 skb->ip_summed = CHECKSUM_PARTIAL; 898 skb->csum_start = skb_transport_header(skb) - skb->head; 899 skb->csum_offset = offsetof(struct udphdr, check); 900 uh->check = ~udp_v4_check(len, saddr, daddr, 0); 901 } 902 } 903 EXPORT_SYMBOL(udp_set_csum); 904 905 static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4, 906 struct inet_cork *cork) 907 { 908 struct sock *sk = skb->sk; 909 struct inet_sock *inet = inet_sk(sk); 910 struct udphdr *uh; 911 int err; 912 int is_udplite = IS_UDPLITE(sk); 913 int offset = skb_transport_offset(skb); 914 int len = skb->len - offset; 915 int datalen = len - sizeof(*uh); 916 __wsum csum = 0; 917 918 /* 919 * Create a UDP header 920 */ 921 uh = udp_hdr(skb); 922 uh->source = inet->inet_sport; 923 uh->dest = fl4->fl4_dport; 924 uh->len = htons(len); 925 uh->check = 0; 926 927 if (cork->gso_size) { 928 const int hlen = skb_network_header_len(skb) + 929 sizeof(struct udphdr); 930 931 if (hlen + cork->gso_size > cork->fragsize) { 932 kfree_skb(skb); 933 return -EINVAL; 934 } 935 if (datalen > cork->gso_size * UDP_MAX_SEGMENTS) { 936 kfree_skb(skb); 937 return -EINVAL; 938 } 939 if (sk->sk_no_check_tx) { 940 kfree_skb(skb); 941 return -EINVAL; 942 } 943 if (is_udplite || dst_xfrm(skb_dst(skb))) { 944 kfree_skb(skb); 945 return -EIO; 946 } 947 948 if (datalen > cork->gso_size) { 949 skb_shinfo(skb)->gso_size = cork->gso_size; 950 skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4; 951 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(datalen, 952 cork->gso_size); 953 } 954 goto csum_partial; 955 } 956 957 if (is_udplite) /* UDP-Lite */ 958 csum = udplite_csum(skb); 959 960 else if (sk->sk_no_check_tx) { /* UDP csum off */ 961 962 skb->ip_summed = CHECKSUM_NONE; 963 goto send; 964 965 } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */ 966 csum_partial: 967 968 udp4_hwcsum(skb, fl4->saddr, fl4->daddr); 969 goto send; 970 971 } else 972 csum = udp_csum(skb); 973 974 /* add protocol-dependent pseudo-header */ 975 uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len, 976 sk->sk_protocol, csum); 977 if (uh->check == 0) 978 uh->check = CSUM_MANGLED_0; 979 980 send: 981 err = ip_send_skb(sock_net(sk), skb); 982 if (err) { 983 if (err == -ENOBUFS && 984 !inet_test_bit(RECVERR, sk)) { 985 UDP_INC_STATS(sock_net(sk), 986 UDP_MIB_SNDBUFERRORS, is_udplite); 987 err = 0; 988 } 989 } else 990 UDP_INC_STATS(sock_net(sk), 991 UDP_MIB_OUTDATAGRAMS, is_udplite); 992 return err; 993 } 994 995 /* 996 * Push out all pending data as one UDP datagram. Socket is locked. 997 */ 998 int udp_push_pending_frames(struct sock *sk) 999 { 1000 struct udp_sock *up = udp_sk(sk); 1001 struct inet_sock *inet = inet_sk(sk); 1002 struct flowi4 *fl4 = &inet->cork.fl.u.ip4; 1003 struct sk_buff *skb; 1004 int err = 0; 1005 1006 skb = ip_finish_skb(sk, fl4); 1007 if (!skb) 1008 goto out; 1009 1010 err = udp_send_skb(skb, fl4, &inet->cork.base); 1011 1012 out: 1013 up->len = 0; 1014 WRITE_ONCE(up->pending, 0); 1015 return err; 1016 } 1017 EXPORT_SYMBOL(udp_push_pending_frames); 1018 1019 static int __udp_cmsg_send(struct cmsghdr *cmsg, u16 *gso_size) 1020 { 1021 switch (cmsg->cmsg_type) { 1022 case UDP_SEGMENT: 1023 if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u16))) 1024 return -EINVAL; 1025 *gso_size = *(__u16 *)CMSG_DATA(cmsg); 1026 return 0; 1027 default: 1028 return -EINVAL; 1029 } 1030 } 1031 1032 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size) 1033 { 1034 struct cmsghdr *cmsg; 1035 bool need_ip = false; 1036 int err; 1037 1038 for_each_cmsghdr(cmsg, msg) { 1039 if (!CMSG_OK(msg, cmsg)) 1040 return -EINVAL; 1041 1042 if (cmsg->cmsg_level != SOL_UDP) { 1043 need_ip = true; 1044 continue; 1045 } 1046 1047 err = __udp_cmsg_send(cmsg, gso_size); 1048 if (err) 1049 return err; 1050 } 1051 1052 return need_ip; 1053 } 1054 EXPORT_SYMBOL_GPL(udp_cmsg_send); 1055 1056 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 1057 { 1058 struct inet_sock *inet = inet_sk(sk); 1059 struct udp_sock *up = udp_sk(sk); 1060 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name); 1061 struct flowi4 fl4_stack; 1062 struct flowi4 *fl4; 1063 int ulen = len; 1064 struct ipcm_cookie ipc; 1065 struct rtable *rt = NULL; 1066 int free = 0; 1067 int connected = 0; 1068 __be32 daddr, faddr, saddr; 1069 u8 tos, scope; 1070 __be16 dport; 1071 int err, is_udplite = IS_UDPLITE(sk); 1072 int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE; 1073 int (*getfrag)(void *, char *, int, int, int, struct sk_buff *); 1074 struct sk_buff *skb; 1075 struct ip_options_data opt_copy; 1076 int uc_index; 1077 1078 if (len > 0xFFFF) 1079 return -EMSGSIZE; 1080 1081 /* 1082 * Check the flags. 1083 */ 1084 1085 if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */ 1086 return -EOPNOTSUPP; 1087 1088 getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag; 1089 1090 fl4 = &inet->cork.fl.u.ip4; 1091 if (READ_ONCE(up->pending)) { 1092 /* 1093 * There are pending frames. 1094 * The socket lock must be held while it's corked. 1095 */ 1096 lock_sock(sk); 1097 if (likely(up->pending)) { 1098 if (unlikely(up->pending != AF_INET)) { 1099 release_sock(sk); 1100 return -EINVAL; 1101 } 1102 goto do_append_data; 1103 } 1104 release_sock(sk); 1105 } 1106 ulen += sizeof(struct udphdr); 1107 1108 /* 1109 * Get and verify the address. 1110 */ 1111 if (usin) { 1112 if (msg->msg_namelen < sizeof(*usin)) 1113 return -EINVAL; 1114 if (usin->sin_family != AF_INET) { 1115 if (usin->sin_family != AF_UNSPEC) 1116 return -EAFNOSUPPORT; 1117 } 1118 1119 daddr = usin->sin_addr.s_addr; 1120 dport = usin->sin_port; 1121 if (dport == 0) 1122 return -EINVAL; 1123 } else { 1124 if (sk->sk_state != TCP_ESTABLISHED) 1125 return -EDESTADDRREQ; 1126 daddr = inet->inet_daddr; 1127 dport = inet->inet_dport; 1128 /* Open fast path for connected socket. 1129 Route will not be used, if at least one option is set. 1130 */ 1131 connected = 1; 1132 } 1133 1134 ipcm_init_sk(&ipc, inet); 1135 ipc.gso_size = READ_ONCE(up->gso_size); 1136 1137 if (msg->msg_controllen) { 1138 err = udp_cmsg_send(sk, msg, &ipc.gso_size); 1139 if (err > 0) { 1140 err = ip_cmsg_send(sk, msg, &ipc, 1141 sk->sk_family == AF_INET6); 1142 connected = 0; 1143 } 1144 if (unlikely(err < 0)) { 1145 kfree(ipc.opt); 1146 return err; 1147 } 1148 if (ipc.opt) 1149 free = 1; 1150 } 1151 if (!ipc.opt) { 1152 struct ip_options_rcu *inet_opt; 1153 1154 rcu_read_lock(); 1155 inet_opt = rcu_dereference(inet->inet_opt); 1156 if (inet_opt) { 1157 memcpy(&opt_copy, inet_opt, 1158 sizeof(*inet_opt) + inet_opt->opt.optlen); 1159 ipc.opt = &opt_copy.opt; 1160 } 1161 rcu_read_unlock(); 1162 } 1163 1164 if (cgroup_bpf_enabled(CGROUP_UDP4_SENDMSG) && !connected) { 1165 err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk, 1166 (struct sockaddr *)usin, 1167 &msg->msg_namelen, 1168 &ipc.addr); 1169 if (err) 1170 goto out_free; 1171 if (usin) { 1172 if (usin->sin_port == 0) { 1173 /* BPF program set invalid port. Reject it. */ 1174 err = -EINVAL; 1175 goto out_free; 1176 } 1177 daddr = usin->sin_addr.s_addr; 1178 dport = usin->sin_port; 1179 } 1180 } 1181 1182 saddr = ipc.addr; 1183 ipc.addr = faddr = daddr; 1184 1185 if (ipc.opt && ipc.opt->opt.srr) { 1186 if (!daddr) { 1187 err = -EINVAL; 1188 goto out_free; 1189 } 1190 faddr = ipc.opt->opt.faddr; 1191 connected = 0; 1192 } 1193 tos = get_rttos(&ipc, inet); 1194 scope = ip_sendmsg_scope(inet, &ipc, msg); 1195 if (scope == RT_SCOPE_LINK) 1196 connected = 0; 1197 1198 uc_index = READ_ONCE(inet->uc_index); 1199 if (ipv4_is_multicast(daddr)) { 1200 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif)) 1201 ipc.oif = READ_ONCE(inet->mc_index); 1202 if (!saddr) 1203 saddr = READ_ONCE(inet->mc_addr); 1204 connected = 0; 1205 } else if (!ipc.oif) { 1206 ipc.oif = uc_index; 1207 } else if (ipv4_is_lbcast(daddr) && uc_index) { 1208 /* oif is set, packet is to local broadcast and 1209 * uc_index is set. oif is most likely set 1210 * by sk_bound_dev_if. If uc_index != oif check if the 1211 * oif is an L3 master and uc_index is an L3 slave. 1212 * If so, we want to allow the send using the uc_index. 1213 */ 1214 if (ipc.oif != uc_index && 1215 ipc.oif == l3mdev_master_ifindex_by_index(sock_net(sk), 1216 uc_index)) { 1217 ipc.oif = uc_index; 1218 } 1219 } 1220 1221 if (connected) 1222 rt = dst_rtable(sk_dst_check(sk, 0)); 1223 1224 if (!rt) { 1225 struct net *net = sock_net(sk); 1226 __u8 flow_flags = inet_sk_flowi_flags(sk); 1227 1228 fl4 = &fl4_stack; 1229 1230 flowi4_init_output(fl4, ipc.oif, ipc.sockc.mark, tos, scope, 1231 sk->sk_protocol, flow_flags, faddr, saddr, 1232 dport, inet->inet_sport, sk->sk_uid); 1233 1234 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4)); 1235 rt = ip_route_output_flow(net, fl4, sk); 1236 if (IS_ERR(rt)) { 1237 err = PTR_ERR(rt); 1238 rt = NULL; 1239 if (err == -ENETUNREACH) 1240 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES); 1241 goto out; 1242 } 1243 1244 err = -EACCES; 1245 if ((rt->rt_flags & RTCF_BROADCAST) && 1246 !sock_flag(sk, SOCK_BROADCAST)) 1247 goto out; 1248 if (connected) 1249 sk_dst_set(sk, dst_clone(&rt->dst)); 1250 } 1251 1252 if (msg->msg_flags&MSG_CONFIRM) 1253 goto do_confirm; 1254 back_from_confirm: 1255 1256 saddr = fl4->saddr; 1257 if (!ipc.addr) 1258 daddr = ipc.addr = fl4->daddr; 1259 1260 /* Lockless fast path for the non-corking case. */ 1261 if (!corkreq) { 1262 struct inet_cork cork; 1263 1264 skb = ip_make_skb(sk, fl4, getfrag, msg, ulen, 1265 sizeof(struct udphdr), &ipc, &rt, 1266 &cork, msg->msg_flags); 1267 err = PTR_ERR(skb); 1268 if (!IS_ERR_OR_NULL(skb)) 1269 err = udp_send_skb(skb, fl4, &cork); 1270 goto out; 1271 } 1272 1273 lock_sock(sk); 1274 if (unlikely(up->pending)) { 1275 /* The socket is already corked while preparing it. */ 1276 /* ... which is an evident application bug. --ANK */ 1277 release_sock(sk); 1278 1279 net_dbg_ratelimited("socket already corked\n"); 1280 err = -EINVAL; 1281 goto out; 1282 } 1283 /* 1284 * Now cork the socket to pend data. 1285 */ 1286 fl4 = &inet->cork.fl.u.ip4; 1287 fl4->daddr = daddr; 1288 fl4->saddr = saddr; 1289 fl4->fl4_dport = dport; 1290 fl4->fl4_sport = inet->inet_sport; 1291 WRITE_ONCE(up->pending, AF_INET); 1292 1293 do_append_data: 1294 up->len += ulen; 1295 err = ip_append_data(sk, fl4, getfrag, msg, ulen, 1296 sizeof(struct udphdr), &ipc, &rt, 1297 corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags); 1298 if (err) 1299 udp_flush_pending_frames(sk); 1300 else if (!corkreq) 1301 err = udp_push_pending_frames(sk); 1302 else if (unlikely(skb_queue_empty(&sk->sk_write_queue))) 1303 WRITE_ONCE(up->pending, 0); 1304 release_sock(sk); 1305 1306 out: 1307 ip_rt_put(rt); 1308 out_free: 1309 if (free) 1310 kfree(ipc.opt); 1311 if (!err) 1312 return len; 1313 /* 1314 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space. Reporting 1315 * ENOBUFS might not be good (it's not tunable per se), but otherwise 1316 * we don't have a good statistic (IpOutDiscards but it can be too many 1317 * things). We could add another new stat but at least for now that 1318 * seems like overkill. 1319 */ 1320 if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) { 1321 UDP_INC_STATS(sock_net(sk), 1322 UDP_MIB_SNDBUFERRORS, is_udplite); 1323 } 1324 return err; 1325 1326 do_confirm: 1327 if (msg->msg_flags & MSG_PROBE) 1328 dst_confirm_neigh(&rt->dst, &fl4->daddr); 1329 if (!(msg->msg_flags&MSG_PROBE) || len) 1330 goto back_from_confirm; 1331 err = 0; 1332 goto out; 1333 } 1334 EXPORT_SYMBOL(udp_sendmsg); 1335 1336 void udp_splice_eof(struct socket *sock) 1337 { 1338 struct sock *sk = sock->sk; 1339 struct udp_sock *up = udp_sk(sk); 1340 1341 if (!READ_ONCE(up->pending) || udp_test_bit(CORK, sk)) 1342 return; 1343 1344 lock_sock(sk); 1345 if (up->pending && !udp_test_bit(CORK, sk)) 1346 udp_push_pending_frames(sk); 1347 release_sock(sk); 1348 } 1349 EXPORT_SYMBOL_GPL(udp_splice_eof); 1350 1351 #define UDP_SKB_IS_STATELESS 0x80000000 1352 1353 /* all head states (dst, sk, nf conntrack) except skb extensions are 1354 * cleared by udp_rcv(). 1355 * 1356 * We need to preserve secpath, if present, to eventually process 1357 * IP_CMSG_PASSSEC at recvmsg() time. 1358 * 1359 * Other extensions can be cleared. 1360 */ 1361 static bool udp_try_make_stateless(struct sk_buff *skb) 1362 { 1363 if (!skb_has_extensions(skb)) 1364 return true; 1365 1366 if (!secpath_exists(skb)) { 1367 skb_ext_reset(skb); 1368 return true; 1369 } 1370 1371 return false; 1372 } 1373 1374 static void udp_set_dev_scratch(struct sk_buff *skb) 1375 { 1376 struct udp_dev_scratch *scratch = udp_skb_scratch(skb); 1377 1378 BUILD_BUG_ON(sizeof(struct udp_dev_scratch) > sizeof(long)); 1379 scratch->_tsize_state = skb->truesize; 1380 #if BITS_PER_LONG == 64 1381 scratch->len = skb->len; 1382 scratch->csum_unnecessary = !!skb_csum_unnecessary(skb); 1383 scratch->is_linear = !skb_is_nonlinear(skb); 1384 #endif 1385 if (udp_try_make_stateless(skb)) 1386 scratch->_tsize_state |= UDP_SKB_IS_STATELESS; 1387 } 1388 1389 static void udp_skb_csum_unnecessary_set(struct sk_buff *skb) 1390 { 1391 /* We come here after udp_lib_checksum_complete() returned 0. 1392 * This means that __skb_checksum_complete() might have 1393 * set skb->csum_valid to 1. 1394 * On 64bit platforms, we can set csum_unnecessary 1395 * to true, but only if the skb is not shared. 1396 */ 1397 #if BITS_PER_LONG == 64 1398 if (!skb_shared(skb)) 1399 udp_skb_scratch(skb)->csum_unnecessary = true; 1400 #endif 1401 } 1402 1403 static int udp_skb_truesize(struct sk_buff *skb) 1404 { 1405 return udp_skb_scratch(skb)->_tsize_state & ~UDP_SKB_IS_STATELESS; 1406 } 1407 1408 static bool udp_skb_has_head_state(struct sk_buff *skb) 1409 { 1410 return !(udp_skb_scratch(skb)->_tsize_state & UDP_SKB_IS_STATELESS); 1411 } 1412 1413 /* fully reclaim rmem/fwd memory allocated for skb */ 1414 static void udp_rmem_release(struct sock *sk, int size, int partial, 1415 bool rx_queue_lock_held) 1416 { 1417 struct udp_sock *up = udp_sk(sk); 1418 struct sk_buff_head *sk_queue; 1419 int amt; 1420 1421 if (likely(partial)) { 1422 up->forward_deficit += size; 1423 size = up->forward_deficit; 1424 if (size < READ_ONCE(up->forward_threshold) && 1425 !skb_queue_empty(&up->reader_queue)) 1426 return; 1427 } else { 1428 size += up->forward_deficit; 1429 } 1430 up->forward_deficit = 0; 1431 1432 /* acquire the sk_receive_queue for fwd allocated memory scheduling, 1433 * if the called don't held it already 1434 */ 1435 sk_queue = &sk->sk_receive_queue; 1436 if (!rx_queue_lock_held) 1437 spin_lock(&sk_queue->lock); 1438 1439 1440 sk_forward_alloc_add(sk, size); 1441 amt = (sk->sk_forward_alloc - partial) & ~(PAGE_SIZE - 1); 1442 sk_forward_alloc_add(sk, -amt); 1443 1444 if (amt) 1445 __sk_mem_reduce_allocated(sk, amt >> PAGE_SHIFT); 1446 1447 atomic_sub(size, &sk->sk_rmem_alloc); 1448 1449 /* this can save us from acquiring the rx queue lock on next receive */ 1450 skb_queue_splice_tail_init(sk_queue, &up->reader_queue); 1451 1452 if (!rx_queue_lock_held) 1453 spin_unlock(&sk_queue->lock); 1454 } 1455 1456 /* Note: called with reader_queue.lock held. 1457 * Instead of using skb->truesize here, find a copy of it in skb->dev_scratch 1458 * This avoids a cache line miss while receive_queue lock is held. 1459 * Look at __udp_enqueue_schedule_skb() to find where this copy is done. 1460 */ 1461 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb) 1462 { 1463 prefetch(&skb->data); 1464 udp_rmem_release(sk, udp_skb_truesize(skb), 1, false); 1465 } 1466 EXPORT_SYMBOL(udp_skb_destructor); 1467 1468 /* as above, but the caller held the rx queue lock, too */ 1469 static void udp_skb_dtor_locked(struct sock *sk, struct sk_buff *skb) 1470 { 1471 prefetch(&skb->data); 1472 udp_rmem_release(sk, udp_skb_truesize(skb), 1, true); 1473 } 1474 1475 /* Idea of busylocks is to let producers grab an extra spinlock 1476 * to relieve pressure on the receive_queue spinlock shared by consumer. 1477 * Under flood, this means that only one producer can be in line 1478 * trying to acquire the receive_queue spinlock. 1479 * These busylock can be allocated on a per cpu manner, instead of a 1480 * per socket one (that would consume a cache line per socket) 1481 */ 1482 static int udp_busylocks_log __read_mostly; 1483 static spinlock_t *udp_busylocks __read_mostly; 1484 1485 static spinlock_t *busylock_acquire(void *ptr) 1486 { 1487 spinlock_t *busy; 1488 1489 busy = udp_busylocks + hash_ptr(ptr, udp_busylocks_log); 1490 spin_lock(busy); 1491 return busy; 1492 } 1493 1494 static void busylock_release(spinlock_t *busy) 1495 { 1496 if (busy) 1497 spin_unlock(busy); 1498 } 1499 1500 static int udp_rmem_schedule(struct sock *sk, int size) 1501 { 1502 int delta; 1503 1504 delta = size - sk->sk_forward_alloc; 1505 if (delta > 0 && !__sk_mem_schedule(sk, delta, SK_MEM_RECV)) 1506 return -ENOBUFS; 1507 1508 return 0; 1509 } 1510 1511 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb) 1512 { 1513 struct sk_buff_head *list = &sk->sk_receive_queue; 1514 int rmem, err = -ENOMEM; 1515 spinlock_t *busy = NULL; 1516 bool becomes_readable; 1517 int size, rcvbuf; 1518 1519 /* Immediately drop when the receive queue is full. 1520 * Always allow at least one packet. 1521 */ 1522 rmem = atomic_read(&sk->sk_rmem_alloc); 1523 rcvbuf = READ_ONCE(sk->sk_rcvbuf); 1524 if (rmem > rcvbuf) 1525 goto drop; 1526 1527 /* Under mem pressure, it might be helpful to help udp_recvmsg() 1528 * having linear skbs : 1529 * - Reduce memory overhead and thus increase receive queue capacity 1530 * - Less cache line misses at copyout() time 1531 * - Less work at consume_skb() (less alien page frag freeing) 1532 */ 1533 if (rmem > (rcvbuf >> 1)) { 1534 skb_condense(skb); 1535 1536 busy = busylock_acquire(sk); 1537 } 1538 size = skb->truesize; 1539 udp_set_dev_scratch(skb); 1540 1541 atomic_add(size, &sk->sk_rmem_alloc); 1542 1543 spin_lock(&list->lock); 1544 err = udp_rmem_schedule(sk, size); 1545 if (err) { 1546 spin_unlock(&list->lock); 1547 goto uncharge_drop; 1548 } 1549 1550 sk_forward_alloc_add(sk, -size); 1551 1552 /* no need to setup a destructor, we will explicitly release the 1553 * forward allocated memory on dequeue 1554 */ 1555 sock_skb_set_dropcount(sk, skb); 1556 1557 becomes_readable = skb_queue_empty(list); 1558 __skb_queue_tail(list, skb); 1559 spin_unlock(&list->lock); 1560 1561 if (!sock_flag(sk, SOCK_DEAD)) { 1562 if (becomes_readable || 1563 sk->sk_data_ready != sock_def_readable || 1564 READ_ONCE(sk->sk_peek_off) >= 0) 1565 INDIRECT_CALL_1(sk->sk_data_ready, 1566 sock_def_readable, sk); 1567 else 1568 sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN); 1569 } 1570 busylock_release(busy); 1571 return 0; 1572 1573 uncharge_drop: 1574 atomic_sub(skb->truesize, &sk->sk_rmem_alloc); 1575 1576 drop: 1577 atomic_inc(&sk->sk_drops); 1578 busylock_release(busy); 1579 return err; 1580 } 1581 EXPORT_SYMBOL_GPL(__udp_enqueue_schedule_skb); 1582 1583 void udp_destruct_common(struct sock *sk) 1584 { 1585 /* reclaim completely the forward allocated memory */ 1586 struct udp_sock *up = udp_sk(sk); 1587 unsigned int total = 0; 1588 struct sk_buff *skb; 1589 1590 skb_queue_splice_tail_init(&sk->sk_receive_queue, &up->reader_queue); 1591 while ((skb = __skb_dequeue(&up->reader_queue)) != NULL) { 1592 total += skb->truesize; 1593 kfree_skb(skb); 1594 } 1595 udp_rmem_release(sk, total, 0, true); 1596 } 1597 EXPORT_SYMBOL_GPL(udp_destruct_common); 1598 1599 static void udp_destruct_sock(struct sock *sk) 1600 { 1601 udp_destruct_common(sk); 1602 inet_sock_destruct(sk); 1603 } 1604 1605 int udp_init_sock(struct sock *sk) 1606 { 1607 udp_lib_init_sock(sk); 1608 sk->sk_destruct = udp_destruct_sock; 1609 set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags); 1610 return 0; 1611 } 1612 1613 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len) 1614 { 1615 if (unlikely(READ_ONCE(udp_sk(sk)->peeking_with_offset))) 1616 sk_peek_offset_bwd(sk, len); 1617 1618 if (!skb_unref(skb)) 1619 return; 1620 1621 /* In the more common cases we cleared the head states previously, 1622 * see __udp_queue_rcv_skb(). 1623 */ 1624 if (unlikely(udp_skb_has_head_state(skb))) 1625 skb_release_head_state(skb); 1626 __consume_stateless_skb(skb); 1627 } 1628 EXPORT_SYMBOL_GPL(skb_consume_udp); 1629 1630 static struct sk_buff *__first_packet_length(struct sock *sk, 1631 struct sk_buff_head *rcvq, 1632 int *total) 1633 { 1634 struct sk_buff *skb; 1635 1636 while ((skb = skb_peek(rcvq)) != NULL) { 1637 if (udp_lib_checksum_complete(skb)) { 1638 __UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, 1639 IS_UDPLITE(sk)); 1640 __UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, 1641 IS_UDPLITE(sk)); 1642 atomic_inc(&sk->sk_drops); 1643 __skb_unlink(skb, rcvq); 1644 *total += skb->truesize; 1645 kfree_skb(skb); 1646 } else { 1647 udp_skb_csum_unnecessary_set(skb); 1648 break; 1649 } 1650 } 1651 return skb; 1652 } 1653 1654 /** 1655 * first_packet_length - return length of first packet in receive queue 1656 * @sk: socket 1657 * 1658 * Drops all bad checksum frames, until a valid one is found. 1659 * Returns the length of found skb, or -1 if none is found. 1660 */ 1661 static int first_packet_length(struct sock *sk) 1662 { 1663 struct sk_buff_head *rcvq = &udp_sk(sk)->reader_queue; 1664 struct sk_buff_head *sk_queue = &sk->sk_receive_queue; 1665 struct sk_buff *skb; 1666 int total = 0; 1667 int res; 1668 1669 spin_lock_bh(&rcvq->lock); 1670 skb = __first_packet_length(sk, rcvq, &total); 1671 if (!skb && !skb_queue_empty_lockless(sk_queue)) { 1672 spin_lock(&sk_queue->lock); 1673 skb_queue_splice_tail_init(sk_queue, rcvq); 1674 spin_unlock(&sk_queue->lock); 1675 1676 skb = __first_packet_length(sk, rcvq, &total); 1677 } 1678 res = skb ? skb->len : -1; 1679 if (total) 1680 udp_rmem_release(sk, total, 1, false); 1681 spin_unlock_bh(&rcvq->lock); 1682 return res; 1683 } 1684 1685 /* 1686 * IOCTL requests applicable to the UDP protocol 1687 */ 1688 1689 int udp_ioctl(struct sock *sk, int cmd, int *karg) 1690 { 1691 switch (cmd) { 1692 case SIOCOUTQ: 1693 { 1694 *karg = sk_wmem_alloc_get(sk); 1695 return 0; 1696 } 1697 1698 case SIOCINQ: 1699 { 1700 *karg = max_t(int, 0, first_packet_length(sk)); 1701 return 0; 1702 } 1703 1704 default: 1705 return -ENOIOCTLCMD; 1706 } 1707 1708 return 0; 1709 } 1710 EXPORT_SYMBOL(udp_ioctl); 1711 1712 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 1713 int *off, int *err) 1714 { 1715 struct sk_buff_head *sk_queue = &sk->sk_receive_queue; 1716 struct sk_buff_head *queue; 1717 struct sk_buff *last; 1718 long timeo; 1719 int error; 1720 1721 queue = &udp_sk(sk)->reader_queue; 1722 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 1723 do { 1724 struct sk_buff *skb; 1725 1726 error = sock_error(sk); 1727 if (error) 1728 break; 1729 1730 error = -EAGAIN; 1731 do { 1732 spin_lock_bh(&queue->lock); 1733 skb = __skb_try_recv_from_queue(sk, queue, flags, off, 1734 err, &last); 1735 if (skb) { 1736 if (!(flags & MSG_PEEK)) 1737 udp_skb_destructor(sk, skb); 1738 spin_unlock_bh(&queue->lock); 1739 return skb; 1740 } 1741 1742 if (skb_queue_empty_lockless(sk_queue)) { 1743 spin_unlock_bh(&queue->lock); 1744 goto busy_check; 1745 } 1746 1747 /* refill the reader queue and walk it again 1748 * keep both queues locked to avoid re-acquiring 1749 * the sk_receive_queue lock if fwd memory scheduling 1750 * is needed. 1751 */ 1752 spin_lock(&sk_queue->lock); 1753 skb_queue_splice_tail_init(sk_queue, queue); 1754 1755 skb = __skb_try_recv_from_queue(sk, queue, flags, off, 1756 err, &last); 1757 if (skb && !(flags & MSG_PEEK)) 1758 udp_skb_dtor_locked(sk, skb); 1759 spin_unlock(&sk_queue->lock); 1760 spin_unlock_bh(&queue->lock); 1761 if (skb) 1762 return skb; 1763 1764 busy_check: 1765 if (!sk_can_busy_loop(sk)) 1766 break; 1767 1768 sk_busy_loop(sk, flags & MSG_DONTWAIT); 1769 } while (!skb_queue_empty_lockless(sk_queue)); 1770 1771 /* sk_queue is empty, reader_queue may contain peeked packets */ 1772 } while (timeo && 1773 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue, 1774 &error, &timeo, 1775 (struct sk_buff *)sk_queue)); 1776 1777 *err = error; 1778 return NULL; 1779 } 1780 EXPORT_SYMBOL(__skb_recv_udp); 1781 1782 int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor) 1783 { 1784 struct sk_buff *skb; 1785 int err; 1786 1787 try_again: 1788 skb = skb_recv_udp(sk, MSG_DONTWAIT, &err); 1789 if (!skb) 1790 return err; 1791 1792 if (udp_lib_checksum_complete(skb)) { 1793 int is_udplite = IS_UDPLITE(sk); 1794 struct net *net = sock_net(sk); 1795 1796 __UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, is_udplite); 1797 __UDP_INC_STATS(net, UDP_MIB_INERRORS, is_udplite); 1798 atomic_inc(&sk->sk_drops); 1799 kfree_skb(skb); 1800 goto try_again; 1801 } 1802 1803 WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk)); 1804 return recv_actor(sk, skb); 1805 } 1806 EXPORT_SYMBOL(udp_read_skb); 1807 1808 /* 1809 * This should be easy, if there is something there we 1810 * return it, otherwise we block. 1811 */ 1812 1813 int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags, 1814 int *addr_len) 1815 { 1816 struct inet_sock *inet = inet_sk(sk); 1817 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); 1818 struct sk_buff *skb; 1819 unsigned int ulen, copied; 1820 int off, err, peeking = flags & MSG_PEEK; 1821 int is_udplite = IS_UDPLITE(sk); 1822 bool checksum_valid = false; 1823 1824 if (flags & MSG_ERRQUEUE) 1825 return ip_recv_error(sk, msg, len, addr_len); 1826 1827 try_again: 1828 off = sk_peek_offset(sk, flags); 1829 skb = __skb_recv_udp(sk, flags, &off, &err); 1830 if (!skb) 1831 return err; 1832 1833 ulen = udp_skb_len(skb); 1834 copied = len; 1835 if (copied > ulen - off) 1836 copied = ulen - off; 1837 else if (copied < ulen) 1838 msg->msg_flags |= MSG_TRUNC; 1839 1840 /* 1841 * If checksum is needed at all, try to do it while copying the 1842 * data. If the data is truncated, or if we only want a partial 1843 * coverage checksum (UDP-Lite), do it before the copy. 1844 */ 1845 1846 if (copied < ulen || peeking || 1847 (is_udplite && UDP_SKB_CB(skb)->partial_cov)) { 1848 checksum_valid = udp_skb_csum_unnecessary(skb) || 1849 !__udp_lib_checksum_complete(skb); 1850 if (!checksum_valid) 1851 goto csum_copy_err; 1852 } 1853 1854 if (checksum_valid || udp_skb_csum_unnecessary(skb)) { 1855 if (udp_skb_is_linear(skb)) 1856 err = copy_linear_skb(skb, copied, off, &msg->msg_iter); 1857 else 1858 err = skb_copy_datagram_msg(skb, off, msg, copied); 1859 } else { 1860 err = skb_copy_and_csum_datagram_msg(skb, off, msg); 1861 1862 if (err == -EINVAL) 1863 goto csum_copy_err; 1864 } 1865 1866 if (unlikely(err)) { 1867 if (!peeking) { 1868 atomic_inc(&sk->sk_drops); 1869 UDP_INC_STATS(sock_net(sk), 1870 UDP_MIB_INERRORS, is_udplite); 1871 } 1872 kfree_skb(skb); 1873 return err; 1874 } 1875 1876 if (!peeking) 1877 UDP_INC_STATS(sock_net(sk), 1878 UDP_MIB_INDATAGRAMS, is_udplite); 1879 1880 sock_recv_cmsgs(msg, sk, skb); 1881 1882 /* Copy the address. */ 1883 if (sin) { 1884 sin->sin_family = AF_INET; 1885 sin->sin_port = udp_hdr(skb)->source; 1886 sin->sin_addr.s_addr = ip_hdr(skb)->saddr; 1887 memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); 1888 *addr_len = sizeof(*sin); 1889 1890 BPF_CGROUP_RUN_PROG_UDP4_RECVMSG_LOCK(sk, 1891 (struct sockaddr *)sin, 1892 addr_len); 1893 } 1894 1895 if (udp_test_bit(GRO_ENABLED, sk)) 1896 udp_cmsg_recv(msg, sk, skb); 1897 1898 if (inet_cmsg_flags(inet)) 1899 ip_cmsg_recv_offset(msg, sk, skb, sizeof(struct udphdr), off); 1900 1901 err = copied; 1902 if (flags & MSG_TRUNC) 1903 err = ulen; 1904 1905 skb_consume_udp(sk, skb, peeking ? -err : err); 1906 return err; 1907 1908 csum_copy_err: 1909 if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags, 1910 udp_skb_destructor)) { 1911 UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite); 1912 UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite); 1913 } 1914 kfree_skb(skb); 1915 1916 /* starting over for a new packet, but check if we need to yield */ 1917 cond_resched(); 1918 msg->msg_flags &= ~MSG_TRUNC; 1919 goto try_again; 1920 } 1921 1922 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 1923 { 1924 /* This check is replicated from __ip4_datagram_connect() and 1925 * intended to prevent BPF program called below from accessing bytes 1926 * that are out of the bound specified by user in addr_len. 1927 */ 1928 if (addr_len < sizeof(struct sockaddr_in)) 1929 return -EINVAL; 1930 1931 return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr, &addr_len); 1932 } 1933 EXPORT_SYMBOL(udp_pre_connect); 1934 1935 int __udp_disconnect(struct sock *sk, int flags) 1936 { 1937 struct inet_sock *inet = inet_sk(sk); 1938 /* 1939 * 1003.1g - break association. 1940 */ 1941 1942 sk->sk_state = TCP_CLOSE; 1943 inet->inet_daddr = 0; 1944 inet->inet_dport = 0; 1945 sock_rps_reset_rxhash(sk); 1946 sk->sk_bound_dev_if = 0; 1947 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) { 1948 inet_reset_saddr(sk); 1949 if (sk->sk_prot->rehash && 1950 (sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1951 sk->sk_prot->rehash(sk); 1952 } 1953 1954 if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) { 1955 sk->sk_prot->unhash(sk); 1956 inet->inet_sport = 0; 1957 } 1958 sk_dst_reset(sk); 1959 return 0; 1960 } 1961 EXPORT_SYMBOL(__udp_disconnect); 1962 1963 int udp_disconnect(struct sock *sk, int flags) 1964 { 1965 lock_sock(sk); 1966 __udp_disconnect(sk, flags); 1967 release_sock(sk); 1968 return 0; 1969 } 1970 EXPORT_SYMBOL(udp_disconnect); 1971 1972 void udp_lib_unhash(struct sock *sk) 1973 { 1974 if (sk_hashed(sk)) { 1975 struct udp_table *udptable = udp_get_table_prot(sk); 1976 struct udp_hslot *hslot, *hslot2; 1977 1978 hslot = udp_hashslot(udptable, sock_net(sk), 1979 udp_sk(sk)->udp_port_hash); 1980 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash); 1981 1982 spin_lock_bh(&hslot->lock); 1983 if (rcu_access_pointer(sk->sk_reuseport_cb)) 1984 reuseport_detach_sock(sk); 1985 if (sk_del_node_init_rcu(sk)) { 1986 hslot->count--; 1987 inet_sk(sk)->inet_num = 0; 1988 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 1989 1990 spin_lock(&hslot2->lock); 1991 hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node); 1992 hslot2->count--; 1993 spin_unlock(&hslot2->lock); 1994 } 1995 spin_unlock_bh(&hslot->lock); 1996 } 1997 } 1998 EXPORT_SYMBOL(udp_lib_unhash); 1999 2000 /* 2001 * inet_rcv_saddr was changed, we must rehash secondary hash 2002 */ 2003 void udp_lib_rehash(struct sock *sk, u16 newhash) 2004 { 2005 if (sk_hashed(sk)) { 2006 struct udp_table *udptable = udp_get_table_prot(sk); 2007 struct udp_hslot *hslot, *hslot2, *nhslot2; 2008 2009 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash); 2010 nhslot2 = udp_hashslot2(udptable, newhash); 2011 udp_sk(sk)->udp_portaddr_hash = newhash; 2012 2013 if (hslot2 != nhslot2 || 2014 rcu_access_pointer(sk->sk_reuseport_cb)) { 2015 hslot = udp_hashslot(udptable, sock_net(sk), 2016 udp_sk(sk)->udp_port_hash); 2017 /* we must lock primary chain too */ 2018 spin_lock_bh(&hslot->lock); 2019 if (rcu_access_pointer(sk->sk_reuseport_cb)) 2020 reuseport_detach_sock(sk); 2021 2022 if (hslot2 != nhslot2) { 2023 spin_lock(&hslot2->lock); 2024 hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node); 2025 hslot2->count--; 2026 spin_unlock(&hslot2->lock); 2027 2028 spin_lock(&nhslot2->lock); 2029 hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node, 2030 &nhslot2->head); 2031 nhslot2->count++; 2032 spin_unlock(&nhslot2->lock); 2033 } 2034 2035 spin_unlock_bh(&hslot->lock); 2036 } 2037 } 2038 } 2039 EXPORT_SYMBOL(udp_lib_rehash); 2040 2041 void udp_v4_rehash(struct sock *sk) 2042 { 2043 u16 new_hash = ipv4_portaddr_hash(sock_net(sk), 2044 inet_sk(sk)->inet_rcv_saddr, 2045 inet_sk(sk)->inet_num); 2046 udp_lib_rehash(sk, new_hash); 2047 } 2048 2049 static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 2050 { 2051 int rc; 2052 2053 if (inet_sk(sk)->inet_daddr) { 2054 sock_rps_save_rxhash(sk, skb); 2055 sk_mark_napi_id(sk, skb); 2056 sk_incoming_cpu_update(sk); 2057 } else { 2058 sk_mark_napi_id_once(sk, skb); 2059 } 2060 2061 rc = __udp_enqueue_schedule_skb(sk, skb); 2062 if (rc < 0) { 2063 int is_udplite = IS_UDPLITE(sk); 2064 int drop_reason; 2065 2066 /* Note that an ENOMEM error is charged twice */ 2067 if (rc == -ENOMEM) { 2068 UDP_INC_STATS(sock_net(sk), UDP_MIB_RCVBUFERRORS, 2069 is_udplite); 2070 drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF; 2071 } else { 2072 UDP_INC_STATS(sock_net(sk), UDP_MIB_MEMERRORS, 2073 is_udplite); 2074 drop_reason = SKB_DROP_REASON_PROTO_MEM; 2075 } 2076 UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite); 2077 trace_udp_fail_queue_rcv_skb(rc, sk, skb); 2078 sk_skb_reason_drop(sk, skb, drop_reason); 2079 return -1; 2080 } 2081 2082 return 0; 2083 } 2084 2085 /* returns: 2086 * -1: error 2087 * 0: success 2088 * >0: "udp encap" protocol resubmission 2089 * 2090 * Note that in the success and error cases, the skb is assumed to 2091 * have either been requeued or freed. 2092 */ 2093 static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb) 2094 { 2095 int drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 2096 struct udp_sock *up = udp_sk(sk); 2097 int is_udplite = IS_UDPLITE(sk); 2098 2099 /* 2100 * Charge it to the socket, dropping if the queue is full. 2101 */ 2102 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) { 2103 drop_reason = SKB_DROP_REASON_XFRM_POLICY; 2104 goto drop; 2105 } 2106 nf_reset_ct(skb); 2107 2108 if (static_branch_unlikely(&udp_encap_needed_key) && 2109 READ_ONCE(up->encap_type)) { 2110 int (*encap_rcv)(struct sock *sk, struct sk_buff *skb); 2111 2112 /* 2113 * This is an encapsulation socket so pass the skb to 2114 * the socket's udp_encap_rcv() hook. Otherwise, just 2115 * fall through and pass this up the UDP socket. 2116 * up->encap_rcv() returns the following value: 2117 * =0 if skb was successfully passed to the encap 2118 * handler or was discarded by it. 2119 * >0 if skb should be passed on to UDP. 2120 * <0 if skb should be resubmitted as proto -N 2121 */ 2122 2123 /* if we're overly short, let UDP handle it */ 2124 encap_rcv = READ_ONCE(up->encap_rcv); 2125 if (encap_rcv) { 2126 int ret; 2127 2128 /* Verify checksum before giving to encap */ 2129 if (udp_lib_checksum_complete(skb)) 2130 goto csum_error; 2131 2132 ret = encap_rcv(sk, skb); 2133 if (ret <= 0) { 2134 __UDP_INC_STATS(sock_net(sk), 2135 UDP_MIB_INDATAGRAMS, 2136 is_udplite); 2137 return -ret; 2138 } 2139 } 2140 2141 /* FALLTHROUGH -- it's a UDP Packet */ 2142 } 2143 2144 /* 2145 * UDP-Lite specific tests, ignored on UDP sockets 2146 */ 2147 if (udp_test_bit(UDPLITE_RECV_CC, sk) && UDP_SKB_CB(skb)->partial_cov) { 2148 u16 pcrlen = READ_ONCE(up->pcrlen); 2149 2150 /* 2151 * MIB statistics other than incrementing the error count are 2152 * disabled for the following two types of errors: these depend 2153 * on the application settings, not on the functioning of the 2154 * protocol stack as such. 2155 * 2156 * RFC 3828 here recommends (sec 3.3): "There should also be a 2157 * way ... to ... at least let the receiving application block 2158 * delivery of packets with coverage values less than a value 2159 * provided by the application." 2160 */ 2161 if (pcrlen == 0) { /* full coverage was set */ 2162 net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n", 2163 UDP_SKB_CB(skb)->cscov, skb->len); 2164 goto drop; 2165 } 2166 /* The next case involves violating the min. coverage requested 2167 * by the receiver. This is subtle: if receiver wants x and x is 2168 * greater than the buffersize/MTU then receiver will complain 2169 * that it wants x while sender emits packets of smaller size y. 2170 * Therefore the above ...()->partial_cov statement is essential. 2171 */ 2172 if (UDP_SKB_CB(skb)->cscov < pcrlen) { 2173 net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n", 2174 UDP_SKB_CB(skb)->cscov, pcrlen); 2175 goto drop; 2176 } 2177 } 2178 2179 prefetch(&sk->sk_rmem_alloc); 2180 if (rcu_access_pointer(sk->sk_filter) && 2181 udp_lib_checksum_complete(skb)) 2182 goto csum_error; 2183 2184 if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr))) { 2185 drop_reason = SKB_DROP_REASON_SOCKET_FILTER; 2186 goto drop; 2187 } 2188 2189 udp_csum_pull_header(skb); 2190 2191 ipv4_pktinfo_prepare(sk, skb, true); 2192 return __udp_queue_rcv_skb(sk, skb); 2193 2194 csum_error: 2195 drop_reason = SKB_DROP_REASON_UDP_CSUM; 2196 __UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite); 2197 drop: 2198 __UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite); 2199 atomic_inc(&sk->sk_drops); 2200 sk_skb_reason_drop(sk, skb, drop_reason); 2201 return -1; 2202 } 2203 2204 static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 2205 { 2206 struct sk_buff *next, *segs; 2207 int ret; 2208 2209 if (likely(!udp_unexpected_gso(sk, skb))) 2210 return udp_queue_rcv_one_skb(sk, skb); 2211 2212 BUILD_BUG_ON(sizeof(struct udp_skb_cb) > SKB_GSO_CB_OFFSET); 2213 __skb_push(skb, -skb_mac_offset(skb)); 2214 segs = udp_rcv_segment(sk, skb, true); 2215 skb_list_walk_safe(segs, skb, next) { 2216 __skb_pull(skb, skb_transport_offset(skb)); 2217 2218 udp_post_segment_fix_csum(skb); 2219 ret = udp_queue_rcv_one_skb(sk, skb); 2220 if (ret > 0) 2221 ip_protocol_deliver_rcu(dev_net(skb->dev), skb, ret); 2222 } 2223 return 0; 2224 } 2225 2226 /* For TCP sockets, sk_rx_dst is protected by socket lock 2227 * For UDP, we use xchg() to guard against concurrent changes. 2228 */ 2229 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst) 2230 { 2231 struct dst_entry *old; 2232 2233 if (dst_hold_safe(dst)) { 2234 old = unrcu_pointer(xchg(&sk->sk_rx_dst, RCU_INITIALIZER(dst))); 2235 dst_release(old); 2236 return old != dst; 2237 } 2238 return false; 2239 } 2240 EXPORT_SYMBOL(udp_sk_rx_dst_set); 2241 2242 /* 2243 * Multicasts and broadcasts go to each listener. 2244 * 2245 * Note: called only from the BH handler context. 2246 */ 2247 static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb, 2248 struct udphdr *uh, 2249 __be32 saddr, __be32 daddr, 2250 struct udp_table *udptable, 2251 int proto) 2252 { 2253 struct sock *sk, *first = NULL; 2254 unsigned short hnum = ntohs(uh->dest); 2255 struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum); 2256 unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10); 2257 unsigned int offset = offsetof(typeof(*sk), sk_node); 2258 int dif = skb->dev->ifindex; 2259 int sdif = inet_sdif(skb); 2260 struct hlist_node *node; 2261 struct sk_buff *nskb; 2262 2263 if (use_hash2) { 2264 hash2_any = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum) & 2265 udptable->mask; 2266 hash2 = ipv4_portaddr_hash(net, daddr, hnum) & udptable->mask; 2267 start_lookup: 2268 hslot = &udptable->hash2[hash2]; 2269 offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node); 2270 } 2271 2272 sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) { 2273 if (!__udp_is_mcast_sock(net, sk, uh->dest, daddr, 2274 uh->source, saddr, dif, sdif, hnum)) 2275 continue; 2276 2277 if (!first) { 2278 first = sk; 2279 continue; 2280 } 2281 nskb = skb_clone(skb, GFP_ATOMIC); 2282 2283 if (unlikely(!nskb)) { 2284 atomic_inc(&sk->sk_drops); 2285 __UDP_INC_STATS(net, UDP_MIB_RCVBUFERRORS, 2286 IS_UDPLITE(sk)); 2287 __UDP_INC_STATS(net, UDP_MIB_INERRORS, 2288 IS_UDPLITE(sk)); 2289 continue; 2290 } 2291 if (udp_queue_rcv_skb(sk, nskb) > 0) 2292 consume_skb(nskb); 2293 } 2294 2295 /* Also lookup *:port if we are using hash2 and haven't done so yet. */ 2296 if (use_hash2 && hash2 != hash2_any) { 2297 hash2 = hash2_any; 2298 goto start_lookup; 2299 } 2300 2301 if (first) { 2302 if (udp_queue_rcv_skb(first, skb) > 0) 2303 consume_skb(skb); 2304 } else { 2305 kfree_skb(skb); 2306 __UDP_INC_STATS(net, UDP_MIB_IGNOREDMULTI, 2307 proto == IPPROTO_UDPLITE); 2308 } 2309 return 0; 2310 } 2311 2312 /* Initialize UDP checksum. If exited with zero value (success), 2313 * CHECKSUM_UNNECESSARY means, that no more checks are required. 2314 * Otherwise, csum completion requires checksumming packet body, 2315 * including udp header and folding it to skb->csum. 2316 */ 2317 static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh, 2318 int proto) 2319 { 2320 int err; 2321 2322 UDP_SKB_CB(skb)->partial_cov = 0; 2323 UDP_SKB_CB(skb)->cscov = skb->len; 2324 2325 if (proto == IPPROTO_UDPLITE) { 2326 err = udplite_checksum_init(skb, uh); 2327 if (err) 2328 return err; 2329 2330 if (UDP_SKB_CB(skb)->partial_cov) { 2331 skb->csum = inet_compute_pseudo(skb, proto); 2332 return 0; 2333 } 2334 } 2335 2336 /* Note, we are only interested in != 0 or == 0, thus the 2337 * force to int. 2338 */ 2339 err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check, 2340 inet_compute_pseudo); 2341 if (err) 2342 return err; 2343 2344 if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) { 2345 /* If SW calculated the value, we know it's bad */ 2346 if (skb->csum_complete_sw) 2347 return 1; 2348 2349 /* HW says the value is bad. Let's validate that. 2350 * skb->csum is no longer the full packet checksum, 2351 * so don't treat it as such. 2352 */ 2353 skb_checksum_complete_unset(skb); 2354 } 2355 2356 return 0; 2357 } 2358 2359 /* wrapper for udp_queue_rcv_skb tacking care of csum conversion and 2360 * return code conversion for ip layer consumption 2361 */ 2362 static int udp_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb, 2363 struct udphdr *uh) 2364 { 2365 int ret; 2366 2367 if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk)) 2368 skb_checksum_try_convert(skb, IPPROTO_UDP, inet_compute_pseudo); 2369 2370 ret = udp_queue_rcv_skb(sk, skb); 2371 2372 /* a return value > 0 means to resubmit the input, but 2373 * it wants the return to be -protocol, or 0 2374 */ 2375 if (ret > 0) 2376 return -ret; 2377 return 0; 2378 } 2379 2380 /* 2381 * All we need to do is get the socket, and then do a checksum. 2382 */ 2383 2384 int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, 2385 int proto) 2386 { 2387 struct sock *sk = NULL; 2388 struct udphdr *uh; 2389 unsigned short ulen; 2390 struct rtable *rt = skb_rtable(skb); 2391 __be32 saddr, daddr; 2392 struct net *net = dev_net(skb->dev); 2393 bool refcounted; 2394 int drop_reason; 2395 2396 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 2397 2398 /* 2399 * Validate the packet. 2400 */ 2401 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 2402 goto drop; /* No space for header. */ 2403 2404 uh = udp_hdr(skb); 2405 ulen = ntohs(uh->len); 2406 saddr = ip_hdr(skb)->saddr; 2407 daddr = ip_hdr(skb)->daddr; 2408 2409 if (ulen > skb->len) 2410 goto short_packet; 2411 2412 if (proto == IPPROTO_UDP) { 2413 /* UDP validates ulen. */ 2414 if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen)) 2415 goto short_packet; 2416 uh = udp_hdr(skb); 2417 } 2418 2419 if (udp4_csum_init(skb, uh, proto)) 2420 goto csum_error; 2421 2422 sk = inet_steal_sock(net, skb, sizeof(struct udphdr), saddr, uh->source, daddr, uh->dest, 2423 &refcounted, udp_ehashfn); 2424 if (IS_ERR(sk)) 2425 goto no_sk; 2426 2427 if (sk) { 2428 struct dst_entry *dst = skb_dst(skb); 2429 int ret; 2430 2431 if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst)) 2432 udp_sk_rx_dst_set(sk, dst); 2433 2434 ret = udp_unicast_rcv_skb(sk, skb, uh); 2435 if (refcounted) 2436 sock_put(sk); 2437 return ret; 2438 } 2439 2440 if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST)) 2441 return __udp4_lib_mcast_deliver(net, skb, uh, 2442 saddr, daddr, udptable, proto); 2443 2444 sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable); 2445 if (sk) 2446 return udp_unicast_rcv_skb(sk, skb, uh); 2447 no_sk: 2448 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 2449 goto drop; 2450 nf_reset_ct(skb); 2451 2452 /* No socket. Drop packet silently, if checksum is wrong */ 2453 if (udp_lib_checksum_complete(skb)) 2454 goto csum_error; 2455 2456 drop_reason = SKB_DROP_REASON_NO_SOCKET; 2457 __UDP_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE); 2458 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); 2459 2460 /* 2461 * Hmm. We got an UDP packet to a port to which we 2462 * don't wanna listen. Ignore it. 2463 */ 2464 sk_skb_reason_drop(sk, skb, drop_reason); 2465 return 0; 2466 2467 short_packet: 2468 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; 2469 net_dbg_ratelimited("UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n", 2470 proto == IPPROTO_UDPLITE ? "Lite" : "", 2471 &saddr, ntohs(uh->source), 2472 ulen, skb->len, 2473 &daddr, ntohs(uh->dest)); 2474 goto drop; 2475 2476 csum_error: 2477 /* 2478 * RFC1122: OK. Discards the bad packet silently (as far as 2479 * the network is concerned, anyway) as per 4.1.3.4 (MUST). 2480 */ 2481 drop_reason = SKB_DROP_REASON_UDP_CSUM; 2482 net_dbg_ratelimited("UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n", 2483 proto == IPPROTO_UDPLITE ? "Lite" : "", 2484 &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest), 2485 ulen); 2486 __UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE); 2487 drop: 2488 __UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE); 2489 sk_skb_reason_drop(sk, skb, drop_reason); 2490 return 0; 2491 } 2492 2493 /* We can only early demux multicast if there is a single matching socket. 2494 * If more than one socket found returns NULL 2495 */ 2496 static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net, 2497 __be16 loc_port, __be32 loc_addr, 2498 __be16 rmt_port, __be32 rmt_addr, 2499 int dif, int sdif) 2500 { 2501 struct udp_table *udptable = net->ipv4.udp_table; 2502 unsigned short hnum = ntohs(loc_port); 2503 struct sock *sk, *result; 2504 struct udp_hslot *hslot; 2505 unsigned int slot; 2506 2507 slot = udp_hashfn(net, hnum, udptable->mask); 2508 hslot = &udptable->hash[slot]; 2509 2510 /* Do not bother scanning a too big list */ 2511 if (hslot->count > 10) 2512 return NULL; 2513 2514 result = NULL; 2515 sk_for_each_rcu(sk, &hslot->head) { 2516 if (__udp_is_mcast_sock(net, sk, loc_port, loc_addr, 2517 rmt_port, rmt_addr, dif, sdif, hnum)) { 2518 if (result) 2519 return NULL; 2520 result = sk; 2521 } 2522 } 2523 2524 return result; 2525 } 2526 2527 /* For unicast we should only early demux connected sockets or we can 2528 * break forwarding setups. The chains here can be long so only check 2529 * if the first socket is an exact match and if not move on. 2530 */ 2531 static struct sock *__udp4_lib_demux_lookup(struct net *net, 2532 __be16 loc_port, __be32 loc_addr, 2533 __be16 rmt_port, __be32 rmt_addr, 2534 int dif, int sdif) 2535 { 2536 struct udp_table *udptable = net->ipv4.udp_table; 2537 INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr); 2538 unsigned short hnum = ntohs(loc_port); 2539 unsigned int hash2, slot2; 2540 struct udp_hslot *hslot2; 2541 __portpair ports; 2542 struct sock *sk; 2543 2544 hash2 = ipv4_portaddr_hash(net, loc_addr, hnum); 2545 slot2 = hash2 & udptable->mask; 2546 hslot2 = &udptable->hash2[slot2]; 2547 ports = INET_COMBINED_PORTS(rmt_port, hnum); 2548 2549 udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) { 2550 if (inet_match(net, sk, acookie, ports, dif, sdif)) 2551 return sk; 2552 /* Only check first socket in chain */ 2553 break; 2554 } 2555 return NULL; 2556 } 2557 2558 int udp_v4_early_demux(struct sk_buff *skb) 2559 { 2560 struct net *net = dev_net(skb->dev); 2561 struct in_device *in_dev = NULL; 2562 const struct iphdr *iph; 2563 const struct udphdr *uh; 2564 struct sock *sk = NULL; 2565 struct dst_entry *dst; 2566 int dif = skb->dev->ifindex; 2567 int sdif = inet_sdif(skb); 2568 int ours; 2569 2570 /* validate the packet */ 2571 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr))) 2572 return 0; 2573 2574 iph = ip_hdr(skb); 2575 uh = udp_hdr(skb); 2576 2577 if (skb->pkt_type == PACKET_MULTICAST) { 2578 in_dev = __in_dev_get_rcu(skb->dev); 2579 2580 if (!in_dev) 2581 return 0; 2582 2583 ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr, 2584 iph->protocol); 2585 if (!ours) 2586 return 0; 2587 2588 sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr, 2589 uh->source, iph->saddr, 2590 dif, sdif); 2591 } else if (skb->pkt_type == PACKET_HOST) { 2592 sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr, 2593 uh->source, iph->saddr, dif, sdif); 2594 } 2595 2596 if (!sk) 2597 return 0; 2598 2599 skb->sk = sk; 2600 DEBUG_NET_WARN_ON_ONCE(sk_is_refcounted(sk)); 2601 skb->destructor = sock_pfree; 2602 dst = rcu_dereference(sk->sk_rx_dst); 2603 2604 if (dst) 2605 dst = dst_check(dst, 0); 2606 if (dst) { 2607 u32 itag = 0; 2608 2609 /* set noref for now. 2610 * any place which wants to hold dst has to call 2611 * dst_hold_safe() 2612 */ 2613 skb_dst_set_noref(skb, dst); 2614 2615 /* for unconnected multicast sockets we need to validate 2616 * the source on each packet 2617 */ 2618 if (!inet_sk(sk)->inet_daddr && in_dev) 2619 return ip_mc_validate_source(skb, iph->daddr, 2620 iph->saddr, 2621 iph->tos & IPTOS_RT_MASK, 2622 skb->dev, in_dev, &itag); 2623 } 2624 return 0; 2625 } 2626 2627 int udp_rcv(struct sk_buff *skb) 2628 { 2629 return __udp4_lib_rcv(skb, dev_net(skb->dev)->ipv4.udp_table, IPPROTO_UDP); 2630 } 2631 2632 void udp_destroy_sock(struct sock *sk) 2633 { 2634 struct udp_sock *up = udp_sk(sk); 2635 bool slow = lock_sock_fast(sk); 2636 2637 /* protects from races with udp_abort() */ 2638 sock_set_flag(sk, SOCK_DEAD); 2639 udp_flush_pending_frames(sk); 2640 unlock_sock_fast(sk, slow); 2641 if (static_branch_unlikely(&udp_encap_needed_key)) { 2642 if (up->encap_type) { 2643 void (*encap_destroy)(struct sock *sk); 2644 encap_destroy = READ_ONCE(up->encap_destroy); 2645 if (encap_destroy) 2646 encap_destroy(sk); 2647 } 2648 if (udp_test_bit(ENCAP_ENABLED, sk)) 2649 static_branch_dec(&udp_encap_needed_key); 2650 } 2651 } 2652 2653 static void set_xfrm_gro_udp_encap_rcv(__u16 encap_type, unsigned short family, 2654 struct sock *sk) 2655 { 2656 #ifdef CONFIG_XFRM 2657 if (udp_test_bit(GRO_ENABLED, sk) && encap_type == UDP_ENCAP_ESPINUDP) { 2658 if (family == AF_INET) 2659 WRITE_ONCE(udp_sk(sk)->gro_receive, xfrm4_gro_udp_encap_rcv); 2660 else if (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) 2661 WRITE_ONCE(udp_sk(sk)->gro_receive, ipv6_stub->xfrm6_gro_udp_encap_rcv); 2662 } 2663 #endif 2664 } 2665 2666 /* 2667 * Socket option code for UDP 2668 */ 2669 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 2670 sockptr_t optval, unsigned int optlen, 2671 int (*push_pending_frames)(struct sock *)) 2672 { 2673 struct udp_sock *up = udp_sk(sk); 2674 int val, valbool; 2675 int err = 0; 2676 int is_udplite = IS_UDPLITE(sk); 2677 2678 if (level == SOL_SOCKET) { 2679 err = sk_setsockopt(sk, level, optname, optval, optlen); 2680 2681 if (optname == SO_RCVBUF || optname == SO_RCVBUFFORCE) { 2682 sockopt_lock_sock(sk); 2683 /* paired with READ_ONCE in udp_rmem_release() */ 2684 WRITE_ONCE(up->forward_threshold, sk->sk_rcvbuf >> 2); 2685 sockopt_release_sock(sk); 2686 } 2687 return err; 2688 } 2689 2690 if (optlen < sizeof(int)) 2691 return -EINVAL; 2692 2693 if (copy_from_sockptr(&val, optval, sizeof(val))) 2694 return -EFAULT; 2695 2696 valbool = val ? 1 : 0; 2697 2698 switch (optname) { 2699 case UDP_CORK: 2700 if (val != 0) { 2701 udp_set_bit(CORK, sk); 2702 } else { 2703 udp_clear_bit(CORK, sk); 2704 lock_sock(sk); 2705 push_pending_frames(sk); 2706 release_sock(sk); 2707 } 2708 break; 2709 2710 case UDP_ENCAP: 2711 switch (val) { 2712 case 0: 2713 #ifdef CONFIG_XFRM 2714 case UDP_ENCAP_ESPINUDP: 2715 set_xfrm_gro_udp_encap_rcv(val, sk->sk_family, sk); 2716 #if IS_ENABLED(CONFIG_IPV6) 2717 if (sk->sk_family == AF_INET6) 2718 WRITE_ONCE(up->encap_rcv, 2719 ipv6_stub->xfrm6_udp_encap_rcv); 2720 else 2721 #endif 2722 WRITE_ONCE(up->encap_rcv, 2723 xfrm4_udp_encap_rcv); 2724 #endif 2725 fallthrough; 2726 case UDP_ENCAP_L2TPINUDP: 2727 WRITE_ONCE(up->encap_type, val); 2728 udp_tunnel_encap_enable(sk); 2729 break; 2730 default: 2731 err = -ENOPROTOOPT; 2732 break; 2733 } 2734 break; 2735 2736 case UDP_NO_CHECK6_TX: 2737 udp_set_no_check6_tx(sk, valbool); 2738 break; 2739 2740 case UDP_NO_CHECK6_RX: 2741 udp_set_no_check6_rx(sk, valbool); 2742 break; 2743 2744 case UDP_SEGMENT: 2745 if (val < 0 || val > USHRT_MAX) 2746 return -EINVAL; 2747 WRITE_ONCE(up->gso_size, val); 2748 break; 2749 2750 case UDP_GRO: 2751 2752 /* when enabling GRO, accept the related GSO packet type */ 2753 if (valbool) 2754 udp_tunnel_encap_enable(sk); 2755 udp_assign_bit(GRO_ENABLED, sk, valbool); 2756 udp_assign_bit(ACCEPT_L4, sk, valbool); 2757 set_xfrm_gro_udp_encap_rcv(up->encap_type, sk->sk_family, sk); 2758 break; 2759 2760 /* 2761 * UDP-Lite's partial checksum coverage (RFC 3828). 2762 */ 2763 /* The sender sets actual checksum coverage length via this option. 2764 * The case coverage > packet length is handled by send module. */ 2765 case UDPLITE_SEND_CSCOV: 2766 if (!is_udplite) /* Disable the option on UDP sockets */ 2767 return -ENOPROTOOPT; 2768 if (val != 0 && val < 8) /* Illegal coverage: use default (8) */ 2769 val = 8; 2770 else if (val > USHRT_MAX) 2771 val = USHRT_MAX; 2772 WRITE_ONCE(up->pcslen, val); 2773 udp_set_bit(UDPLITE_SEND_CC, sk); 2774 break; 2775 2776 /* The receiver specifies a minimum checksum coverage value. To make 2777 * sense, this should be set to at least 8 (as done below). If zero is 2778 * used, this again means full checksum coverage. */ 2779 case UDPLITE_RECV_CSCOV: 2780 if (!is_udplite) /* Disable the option on UDP sockets */ 2781 return -ENOPROTOOPT; 2782 if (val != 0 && val < 8) /* Avoid silly minimal values. */ 2783 val = 8; 2784 else if (val > USHRT_MAX) 2785 val = USHRT_MAX; 2786 WRITE_ONCE(up->pcrlen, val); 2787 udp_set_bit(UDPLITE_RECV_CC, sk); 2788 break; 2789 2790 default: 2791 err = -ENOPROTOOPT; 2792 break; 2793 } 2794 2795 return err; 2796 } 2797 EXPORT_SYMBOL(udp_lib_setsockopt); 2798 2799 int udp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, 2800 unsigned int optlen) 2801 { 2802 if (level == SOL_UDP || level == SOL_UDPLITE || level == SOL_SOCKET) 2803 return udp_lib_setsockopt(sk, level, optname, 2804 optval, optlen, 2805 udp_push_pending_frames); 2806 return ip_setsockopt(sk, level, optname, optval, optlen); 2807 } 2808 2809 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 2810 char __user *optval, int __user *optlen) 2811 { 2812 struct udp_sock *up = udp_sk(sk); 2813 int val, len; 2814 2815 if (get_user(len, optlen)) 2816 return -EFAULT; 2817 2818 if (len < 0) 2819 return -EINVAL; 2820 2821 len = min_t(unsigned int, len, sizeof(int)); 2822 2823 switch (optname) { 2824 case UDP_CORK: 2825 val = udp_test_bit(CORK, sk); 2826 break; 2827 2828 case UDP_ENCAP: 2829 val = READ_ONCE(up->encap_type); 2830 break; 2831 2832 case UDP_NO_CHECK6_TX: 2833 val = udp_get_no_check6_tx(sk); 2834 break; 2835 2836 case UDP_NO_CHECK6_RX: 2837 val = udp_get_no_check6_rx(sk); 2838 break; 2839 2840 case UDP_SEGMENT: 2841 val = READ_ONCE(up->gso_size); 2842 break; 2843 2844 case UDP_GRO: 2845 val = udp_test_bit(GRO_ENABLED, sk); 2846 break; 2847 2848 /* The following two cannot be changed on UDP sockets, the return is 2849 * always 0 (which corresponds to the full checksum coverage of UDP). */ 2850 case UDPLITE_SEND_CSCOV: 2851 val = READ_ONCE(up->pcslen); 2852 break; 2853 2854 case UDPLITE_RECV_CSCOV: 2855 val = READ_ONCE(up->pcrlen); 2856 break; 2857 2858 default: 2859 return -ENOPROTOOPT; 2860 } 2861 2862 if (put_user(len, optlen)) 2863 return -EFAULT; 2864 if (copy_to_user(optval, &val, len)) 2865 return -EFAULT; 2866 return 0; 2867 } 2868 EXPORT_SYMBOL(udp_lib_getsockopt); 2869 2870 int udp_getsockopt(struct sock *sk, int level, int optname, 2871 char __user *optval, int __user *optlen) 2872 { 2873 if (level == SOL_UDP || level == SOL_UDPLITE) 2874 return udp_lib_getsockopt(sk, level, optname, optval, optlen); 2875 return ip_getsockopt(sk, level, optname, optval, optlen); 2876 } 2877 2878 /** 2879 * udp_poll - wait for a UDP event. 2880 * @file: - file struct 2881 * @sock: - socket 2882 * @wait: - poll table 2883 * 2884 * This is same as datagram poll, except for the special case of 2885 * blocking sockets. If application is using a blocking fd 2886 * and a packet with checksum error is in the queue; 2887 * then it could get return from select indicating data available 2888 * but then block when reading it. Add special case code 2889 * to work around these arguably broken applications. 2890 */ 2891 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait) 2892 { 2893 __poll_t mask = datagram_poll(file, sock, wait); 2894 struct sock *sk = sock->sk; 2895 2896 if (!skb_queue_empty_lockless(&udp_sk(sk)->reader_queue)) 2897 mask |= EPOLLIN | EPOLLRDNORM; 2898 2899 /* Check for false positives due to checksum errors */ 2900 if ((mask & EPOLLRDNORM) && !(file->f_flags & O_NONBLOCK) && 2901 !(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -1) 2902 mask &= ~(EPOLLIN | EPOLLRDNORM); 2903 2904 /* psock ingress_msg queue should not contain any bad checksum frames */ 2905 if (sk_is_readable(sk)) 2906 mask |= EPOLLIN | EPOLLRDNORM; 2907 return mask; 2908 2909 } 2910 EXPORT_SYMBOL(udp_poll); 2911 2912 int udp_abort(struct sock *sk, int err) 2913 { 2914 if (!has_current_bpf_ctx()) 2915 lock_sock(sk); 2916 2917 /* udp{v6}_destroy_sock() sets it under the sk lock, avoid racing 2918 * with close() 2919 */ 2920 if (sock_flag(sk, SOCK_DEAD)) 2921 goto out; 2922 2923 sk->sk_err = err; 2924 sk_error_report(sk); 2925 __udp_disconnect(sk, 0); 2926 2927 out: 2928 if (!has_current_bpf_ctx()) 2929 release_sock(sk); 2930 2931 return 0; 2932 } 2933 EXPORT_SYMBOL_GPL(udp_abort); 2934 2935 struct proto udp_prot = { 2936 .name = "UDP", 2937 .owner = THIS_MODULE, 2938 .close = udp_lib_close, 2939 .pre_connect = udp_pre_connect, 2940 .connect = ip4_datagram_connect, 2941 .disconnect = udp_disconnect, 2942 .ioctl = udp_ioctl, 2943 .init = udp_init_sock, 2944 .destroy = udp_destroy_sock, 2945 .setsockopt = udp_setsockopt, 2946 .getsockopt = udp_getsockopt, 2947 .sendmsg = udp_sendmsg, 2948 .recvmsg = udp_recvmsg, 2949 .splice_eof = udp_splice_eof, 2950 .release_cb = ip4_datagram_release_cb, 2951 .hash = udp_lib_hash, 2952 .unhash = udp_lib_unhash, 2953 .rehash = udp_v4_rehash, 2954 .get_port = udp_v4_get_port, 2955 .put_port = udp_lib_unhash, 2956 #ifdef CONFIG_BPF_SYSCALL 2957 .psock_update_sk_prot = udp_bpf_update_proto, 2958 #endif 2959 .memory_allocated = &udp_memory_allocated, 2960 .per_cpu_fw_alloc = &udp_memory_per_cpu_fw_alloc, 2961 2962 .sysctl_mem = sysctl_udp_mem, 2963 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min), 2964 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_udp_rmem_min), 2965 .obj_size = sizeof(struct udp_sock), 2966 .h.udp_table = NULL, 2967 .diag_destroy = udp_abort, 2968 }; 2969 EXPORT_SYMBOL(udp_prot); 2970 2971 /* ------------------------------------------------------------------------ */ 2972 #ifdef CONFIG_PROC_FS 2973 2974 static unsigned short seq_file_family(const struct seq_file *seq); 2975 static bool seq_sk_match(struct seq_file *seq, const struct sock *sk) 2976 { 2977 unsigned short family = seq_file_family(seq); 2978 2979 /* AF_UNSPEC is used as a match all */ 2980 return ((family == AF_UNSPEC || family == sk->sk_family) && 2981 net_eq(sock_net(sk), seq_file_net(seq))); 2982 } 2983 2984 #ifdef CONFIG_BPF_SYSCALL 2985 static const struct seq_operations bpf_iter_udp_seq_ops; 2986 #endif 2987 static struct udp_table *udp_get_table_seq(struct seq_file *seq, 2988 struct net *net) 2989 { 2990 const struct udp_seq_afinfo *afinfo; 2991 2992 #ifdef CONFIG_BPF_SYSCALL 2993 if (seq->op == &bpf_iter_udp_seq_ops) 2994 return net->ipv4.udp_table; 2995 #endif 2996 2997 afinfo = pde_data(file_inode(seq->file)); 2998 return afinfo->udp_table ? : net->ipv4.udp_table; 2999 } 3000 3001 static struct sock *udp_get_first(struct seq_file *seq, int start) 3002 { 3003 struct udp_iter_state *state = seq->private; 3004 struct net *net = seq_file_net(seq); 3005 struct udp_table *udptable; 3006 struct sock *sk; 3007 3008 udptable = udp_get_table_seq(seq, net); 3009 3010 for (state->bucket = start; state->bucket <= udptable->mask; 3011 ++state->bucket) { 3012 struct udp_hslot *hslot = &udptable->hash[state->bucket]; 3013 3014 if (hlist_empty(&hslot->head)) 3015 continue; 3016 3017 spin_lock_bh(&hslot->lock); 3018 sk_for_each(sk, &hslot->head) { 3019 if (seq_sk_match(seq, sk)) 3020 goto found; 3021 } 3022 spin_unlock_bh(&hslot->lock); 3023 } 3024 sk = NULL; 3025 found: 3026 return sk; 3027 } 3028 3029 static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk) 3030 { 3031 struct udp_iter_state *state = seq->private; 3032 struct net *net = seq_file_net(seq); 3033 struct udp_table *udptable; 3034 3035 do { 3036 sk = sk_next(sk); 3037 } while (sk && !seq_sk_match(seq, sk)); 3038 3039 if (!sk) { 3040 udptable = udp_get_table_seq(seq, net); 3041 3042 if (state->bucket <= udptable->mask) 3043 spin_unlock_bh(&udptable->hash[state->bucket].lock); 3044 3045 return udp_get_first(seq, state->bucket + 1); 3046 } 3047 return sk; 3048 } 3049 3050 static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos) 3051 { 3052 struct sock *sk = udp_get_first(seq, 0); 3053 3054 if (sk) 3055 while (pos && (sk = udp_get_next(seq, sk)) != NULL) 3056 --pos; 3057 return pos ? NULL : sk; 3058 } 3059 3060 void *udp_seq_start(struct seq_file *seq, loff_t *pos) 3061 { 3062 struct udp_iter_state *state = seq->private; 3063 state->bucket = MAX_UDP_PORTS; 3064 3065 return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN; 3066 } 3067 EXPORT_SYMBOL(udp_seq_start); 3068 3069 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 3070 { 3071 struct sock *sk; 3072 3073 if (v == SEQ_START_TOKEN) 3074 sk = udp_get_idx(seq, 0); 3075 else 3076 sk = udp_get_next(seq, v); 3077 3078 ++*pos; 3079 return sk; 3080 } 3081 EXPORT_SYMBOL(udp_seq_next); 3082 3083 void udp_seq_stop(struct seq_file *seq, void *v) 3084 { 3085 struct udp_iter_state *state = seq->private; 3086 struct udp_table *udptable; 3087 3088 udptable = udp_get_table_seq(seq, seq_file_net(seq)); 3089 3090 if (state->bucket <= udptable->mask) 3091 spin_unlock_bh(&udptable->hash[state->bucket].lock); 3092 } 3093 EXPORT_SYMBOL(udp_seq_stop); 3094 3095 /* ------------------------------------------------------------------------ */ 3096 static void udp4_format_sock(struct sock *sp, struct seq_file *f, 3097 int bucket) 3098 { 3099 struct inet_sock *inet = inet_sk(sp); 3100 __be32 dest = inet->inet_daddr; 3101 __be32 src = inet->inet_rcv_saddr; 3102 __u16 destp = ntohs(inet->inet_dport); 3103 __u16 srcp = ntohs(inet->inet_sport); 3104 3105 seq_printf(f, "%5d: %08X:%04X %08X:%04X" 3106 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u", 3107 bucket, src, srcp, dest, destp, sp->sk_state, 3108 sk_wmem_alloc_get(sp), 3109 udp_rqueue_get(sp), 3110 0, 0L, 0, 3111 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)), 3112 0, sock_i_ino(sp), 3113 refcount_read(&sp->sk_refcnt), sp, 3114 atomic_read(&sp->sk_drops)); 3115 } 3116 3117 int udp4_seq_show(struct seq_file *seq, void *v) 3118 { 3119 seq_setwidth(seq, 127); 3120 if (v == SEQ_START_TOKEN) 3121 seq_puts(seq, " sl local_address rem_address st tx_queue " 3122 "rx_queue tr tm->when retrnsmt uid timeout " 3123 "inode ref pointer drops"); 3124 else { 3125 struct udp_iter_state *state = seq->private; 3126 3127 udp4_format_sock(v, seq, state->bucket); 3128 } 3129 seq_pad(seq, '\n'); 3130 return 0; 3131 } 3132 3133 #ifdef CONFIG_BPF_SYSCALL 3134 struct bpf_iter__udp { 3135 __bpf_md_ptr(struct bpf_iter_meta *, meta); 3136 __bpf_md_ptr(struct udp_sock *, udp_sk); 3137 uid_t uid __aligned(8); 3138 int bucket __aligned(8); 3139 }; 3140 3141 struct bpf_udp_iter_state { 3142 struct udp_iter_state state; 3143 unsigned int cur_sk; 3144 unsigned int end_sk; 3145 unsigned int max_sk; 3146 int offset; 3147 struct sock **batch; 3148 bool st_bucket_done; 3149 }; 3150 3151 static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter, 3152 unsigned int new_batch_sz); 3153 static struct sock *bpf_iter_udp_batch(struct seq_file *seq) 3154 { 3155 struct bpf_udp_iter_state *iter = seq->private; 3156 struct udp_iter_state *state = &iter->state; 3157 struct net *net = seq_file_net(seq); 3158 int resume_bucket, resume_offset; 3159 struct udp_table *udptable; 3160 unsigned int batch_sks = 0; 3161 bool resized = false; 3162 struct sock *sk; 3163 3164 resume_bucket = state->bucket; 3165 resume_offset = iter->offset; 3166 3167 /* The current batch is done, so advance the bucket. */ 3168 if (iter->st_bucket_done) 3169 state->bucket++; 3170 3171 udptable = udp_get_table_seq(seq, net); 3172 3173 again: 3174 /* New batch for the next bucket. 3175 * Iterate over the hash table to find a bucket with sockets matching 3176 * the iterator attributes, and return the first matching socket from 3177 * the bucket. The remaining matched sockets from the bucket are batched 3178 * before releasing the bucket lock. This allows BPF programs that are 3179 * called in seq_show to acquire the bucket lock if needed. 3180 */ 3181 iter->cur_sk = 0; 3182 iter->end_sk = 0; 3183 iter->st_bucket_done = false; 3184 batch_sks = 0; 3185 3186 for (; state->bucket <= udptable->mask; state->bucket++) { 3187 struct udp_hslot *hslot2 = &udptable->hash2[state->bucket]; 3188 3189 if (hlist_empty(&hslot2->head)) 3190 continue; 3191 3192 iter->offset = 0; 3193 spin_lock_bh(&hslot2->lock); 3194 udp_portaddr_for_each_entry(sk, &hslot2->head) { 3195 if (seq_sk_match(seq, sk)) { 3196 /* Resume from the last iterated socket at the 3197 * offset in the bucket before iterator was stopped. 3198 */ 3199 if (state->bucket == resume_bucket && 3200 iter->offset < resume_offset) { 3201 ++iter->offset; 3202 continue; 3203 } 3204 if (iter->end_sk < iter->max_sk) { 3205 sock_hold(sk); 3206 iter->batch[iter->end_sk++] = sk; 3207 } 3208 batch_sks++; 3209 } 3210 } 3211 spin_unlock_bh(&hslot2->lock); 3212 3213 if (iter->end_sk) 3214 break; 3215 } 3216 3217 /* All done: no batch made. */ 3218 if (!iter->end_sk) 3219 return NULL; 3220 3221 if (iter->end_sk == batch_sks) { 3222 /* Batching is done for the current bucket; return the first 3223 * socket to be iterated from the batch. 3224 */ 3225 iter->st_bucket_done = true; 3226 goto done; 3227 } 3228 if (!resized && !bpf_iter_udp_realloc_batch(iter, batch_sks * 3 / 2)) { 3229 resized = true; 3230 /* After allocating a larger batch, retry one more time to grab 3231 * the whole bucket. 3232 */ 3233 goto again; 3234 } 3235 done: 3236 return iter->batch[0]; 3237 } 3238 3239 static void *bpf_iter_udp_seq_next(struct seq_file *seq, void *v, loff_t *pos) 3240 { 3241 struct bpf_udp_iter_state *iter = seq->private; 3242 struct sock *sk; 3243 3244 /* Whenever seq_next() is called, the iter->cur_sk is 3245 * done with seq_show(), so unref the iter->cur_sk. 3246 */ 3247 if (iter->cur_sk < iter->end_sk) { 3248 sock_put(iter->batch[iter->cur_sk++]); 3249 ++iter->offset; 3250 } 3251 3252 /* After updating iter->cur_sk, check if there are more sockets 3253 * available in the current bucket batch. 3254 */ 3255 if (iter->cur_sk < iter->end_sk) 3256 sk = iter->batch[iter->cur_sk]; 3257 else 3258 /* Prepare a new batch. */ 3259 sk = bpf_iter_udp_batch(seq); 3260 3261 ++*pos; 3262 return sk; 3263 } 3264 3265 static void *bpf_iter_udp_seq_start(struct seq_file *seq, loff_t *pos) 3266 { 3267 /* bpf iter does not support lseek, so it always 3268 * continue from where it was stop()-ped. 3269 */ 3270 if (*pos) 3271 return bpf_iter_udp_batch(seq); 3272 3273 return SEQ_START_TOKEN; 3274 } 3275 3276 static int udp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta, 3277 struct udp_sock *udp_sk, uid_t uid, int bucket) 3278 { 3279 struct bpf_iter__udp ctx; 3280 3281 meta->seq_num--; /* skip SEQ_START_TOKEN */ 3282 ctx.meta = meta; 3283 ctx.udp_sk = udp_sk; 3284 ctx.uid = uid; 3285 ctx.bucket = bucket; 3286 return bpf_iter_run_prog(prog, &ctx); 3287 } 3288 3289 static int bpf_iter_udp_seq_show(struct seq_file *seq, void *v) 3290 { 3291 struct udp_iter_state *state = seq->private; 3292 struct bpf_iter_meta meta; 3293 struct bpf_prog *prog; 3294 struct sock *sk = v; 3295 uid_t uid; 3296 int ret; 3297 3298 if (v == SEQ_START_TOKEN) 3299 return 0; 3300 3301 lock_sock(sk); 3302 3303 if (unlikely(sk_unhashed(sk))) { 3304 ret = SEQ_SKIP; 3305 goto unlock; 3306 } 3307 3308 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)); 3309 meta.seq = seq; 3310 prog = bpf_iter_get_info(&meta, false); 3311 ret = udp_prog_seq_show(prog, &meta, v, uid, state->bucket); 3312 3313 unlock: 3314 release_sock(sk); 3315 return ret; 3316 } 3317 3318 static void bpf_iter_udp_put_batch(struct bpf_udp_iter_state *iter) 3319 { 3320 while (iter->cur_sk < iter->end_sk) 3321 sock_put(iter->batch[iter->cur_sk++]); 3322 } 3323 3324 static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v) 3325 { 3326 struct bpf_udp_iter_state *iter = seq->private; 3327 struct bpf_iter_meta meta; 3328 struct bpf_prog *prog; 3329 3330 if (!v) { 3331 meta.seq = seq; 3332 prog = bpf_iter_get_info(&meta, true); 3333 if (prog) 3334 (void)udp_prog_seq_show(prog, &meta, v, 0, 0); 3335 } 3336 3337 if (iter->cur_sk < iter->end_sk) { 3338 bpf_iter_udp_put_batch(iter); 3339 iter->st_bucket_done = false; 3340 } 3341 } 3342 3343 static const struct seq_operations bpf_iter_udp_seq_ops = { 3344 .start = bpf_iter_udp_seq_start, 3345 .next = bpf_iter_udp_seq_next, 3346 .stop = bpf_iter_udp_seq_stop, 3347 .show = bpf_iter_udp_seq_show, 3348 }; 3349 #endif 3350 3351 static unsigned short seq_file_family(const struct seq_file *seq) 3352 { 3353 const struct udp_seq_afinfo *afinfo; 3354 3355 #ifdef CONFIG_BPF_SYSCALL 3356 /* BPF iterator: bpf programs to filter sockets. */ 3357 if (seq->op == &bpf_iter_udp_seq_ops) 3358 return AF_UNSPEC; 3359 #endif 3360 3361 /* Proc fs iterator */ 3362 afinfo = pde_data(file_inode(seq->file)); 3363 return afinfo->family; 3364 } 3365 3366 const struct seq_operations udp_seq_ops = { 3367 .start = udp_seq_start, 3368 .next = udp_seq_next, 3369 .stop = udp_seq_stop, 3370 .show = udp4_seq_show, 3371 }; 3372 EXPORT_SYMBOL(udp_seq_ops); 3373 3374 static struct udp_seq_afinfo udp4_seq_afinfo = { 3375 .family = AF_INET, 3376 .udp_table = NULL, 3377 }; 3378 3379 static int __net_init udp4_proc_init_net(struct net *net) 3380 { 3381 if (!proc_create_net_data("udp", 0444, net->proc_net, &udp_seq_ops, 3382 sizeof(struct udp_iter_state), &udp4_seq_afinfo)) 3383 return -ENOMEM; 3384 return 0; 3385 } 3386 3387 static void __net_exit udp4_proc_exit_net(struct net *net) 3388 { 3389 remove_proc_entry("udp", net->proc_net); 3390 } 3391 3392 static struct pernet_operations udp4_net_ops = { 3393 .init = udp4_proc_init_net, 3394 .exit = udp4_proc_exit_net, 3395 }; 3396 3397 int __init udp4_proc_init(void) 3398 { 3399 return register_pernet_subsys(&udp4_net_ops); 3400 } 3401 3402 void udp4_proc_exit(void) 3403 { 3404 unregister_pernet_subsys(&udp4_net_ops); 3405 } 3406 #endif /* CONFIG_PROC_FS */ 3407 3408 static __initdata unsigned long uhash_entries; 3409 static int __init set_uhash_entries(char *str) 3410 { 3411 ssize_t ret; 3412 3413 if (!str) 3414 return 0; 3415 3416 ret = kstrtoul(str, 0, &uhash_entries); 3417 if (ret) 3418 return 0; 3419 3420 if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN) 3421 uhash_entries = UDP_HTABLE_SIZE_MIN; 3422 return 1; 3423 } 3424 __setup("uhash_entries=", set_uhash_entries); 3425 3426 void __init udp_table_init(struct udp_table *table, const char *name) 3427 { 3428 unsigned int i; 3429 3430 table->hash = alloc_large_system_hash(name, 3431 2 * sizeof(struct udp_hslot), 3432 uhash_entries, 3433 21, /* one slot per 2 MB */ 3434 0, 3435 &table->log, 3436 &table->mask, 3437 UDP_HTABLE_SIZE_MIN, 3438 UDP_HTABLE_SIZE_MAX); 3439 3440 table->hash2 = table->hash + (table->mask + 1); 3441 for (i = 0; i <= table->mask; i++) { 3442 INIT_HLIST_HEAD(&table->hash[i].head); 3443 table->hash[i].count = 0; 3444 spin_lock_init(&table->hash[i].lock); 3445 } 3446 for (i = 0; i <= table->mask; i++) { 3447 INIT_HLIST_HEAD(&table->hash2[i].head); 3448 table->hash2[i].count = 0; 3449 spin_lock_init(&table->hash2[i].lock); 3450 } 3451 } 3452 3453 u32 udp_flow_hashrnd(void) 3454 { 3455 static u32 hashrnd __read_mostly; 3456 3457 net_get_random_once(&hashrnd, sizeof(hashrnd)); 3458 3459 return hashrnd; 3460 } 3461 EXPORT_SYMBOL(udp_flow_hashrnd); 3462 3463 static void __net_init udp_sysctl_init(struct net *net) 3464 { 3465 net->ipv4.sysctl_udp_rmem_min = PAGE_SIZE; 3466 net->ipv4.sysctl_udp_wmem_min = PAGE_SIZE; 3467 3468 #ifdef CONFIG_NET_L3_MASTER_DEV 3469 net->ipv4.sysctl_udp_l3mdev_accept = 0; 3470 #endif 3471 } 3472 3473 static struct udp_table __net_init *udp_pernet_table_alloc(unsigned int hash_entries) 3474 { 3475 struct udp_table *udptable; 3476 int i; 3477 3478 udptable = kmalloc(sizeof(*udptable), GFP_KERNEL); 3479 if (!udptable) 3480 goto out; 3481 3482 udptable->hash = vmalloc_huge(hash_entries * 2 * sizeof(struct udp_hslot), 3483 GFP_KERNEL_ACCOUNT); 3484 if (!udptable->hash) 3485 goto free_table; 3486 3487 udptable->hash2 = udptable->hash + hash_entries; 3488 udptable->mask = hash_entries - 1; 3489 udptable->log = ilog2(hash_entries); 3490 3491 for (i = 0; i < hash_entries; i++) { 3492 INIT_HLIST_HEAD(&udptable->hash[i].head); 3493 udptable->hash[i].count = 0; 3494 spin_lock_init(&udptable->hash[i].lock); 3495 3496 INIT_HLIST_HEAD(&udptable->hash2[i].head); 3497 udptable->hash2[i].count = 0; 3498 spin_lock_init(&udptable->hash2[i].lock); 3499 } 3500 3501 return udptable; 3502 3503 free_table: 3504 kfree(udptable); 3505 out: 3506 return NULL; 3507 } 3508 3509 static void __net_exit udp_pernet_table_free(struct net *net) 3510 { 3511 struct udp_table *udptable = net->ipv4.udp_table; 3512 3513 if (udptable == &udp_table) 3514 return; 3515 3516 kvfree(udptable->hash); 3517 kfree(udptable); 3518 } 3519 3520 static void __net_init udp_set_table(struct net *net) 3521 { 3522 struct udp_table *udptable; 3523 unsigned int hash_entries; 3524 struct net *old_net; 3525 3526 if (net_eq(net, &init_net)) 3527 goto fallback; 3528 3529 old_net = current->nsproxy->net_ns; 3530 hash_entries = READ_ONCE(old_net->ipv4.sysctl_udp_child_hash_entries); 3531 if (!hash_entries) 3532 goto fallback; 3533 3534 /* Set min to keep the bitmap on stack in udp_lib_get_port() */ 3535 if (hash_entries < UDP_HTABLE_SIZE_MIN_PERNET) 3536 hash_entries = UDP_HTABLE_SIZE_MIN_PERNET; 3537 else 3538 hash_entries = roundup_pow_of_two(hash_entries); 3539 3540 udptable = udp_pernet_table_alloc(hash_entries); 3541 if (udptable) { 3542 net->ipv4.udp_table = udptable; 3543 } else { 3544 pr_warn("Failed to allocate UDP hash table (entries: %u) " 3545 "for a netns, fallback to the global one\n", 3546 hash_entries); 3547 fallback: 3548 net->ipv4.udp_table = &udp_table; 3549 } 3550 } 3551 3552 static int __net_init udp_pernet_init(struct net *net) 3553 { 3554 udp_sysctl_init(net); 3555 udp_set_table(net); 3556 3557 return 0; 3558 } 3559 3560 static void __net_exit udp_pernet_exit(struct net *net) 3561 { 3562 udp_pernet_table_free(net); 3563 } 3564 3565 static struct pernet_operations __net_initdata udp_sysctl_ops = { 3566 .init = udp_pernet_init, 3567 .exit = udp_pernet_exit, 3568 }; 3569 3570 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 3571 DEFINE_BPF_ITER_FUNC(udp, struct bpf_iter_meta *meta, 3572 struct udp_sock *udp_sk, uid_t uid, int bucket) 3573 3574 static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter, 3575 unsigned int new_batch_sz) 3576 { 3577 struct sock **new_batch; 3578 3579 new_batch = kvmalloc_array(new_batch_sz, sizeof(*new_batch), 3580 GFP_USER | __GFP_NOWARN); 3581 if (!new_batch) 3582 return -ENOMEM; 3583 3584 bpf_iter_udp_put_batch(iter); 3585 kvfree(iter->batch); 3586 iter->batch = new_batch; 3587 iter->max_sk = new_batch_sz; 3588 3589 return 0; 3590 } 3591 3592 #define INIT_BATCH_SZ 16 3593 3594 static int bpf_iter_init_udp(void *priv_data, struct bpf_iter_aux_info *aux) 3595 { 3596 struct bpf_udp_iter_state *iter = priv_data; 3597 int ret; 3598 3599 ret = bpf_iter_init_seq_net(priv_data, aux); 3600 if (ret) 3601 return ret; 3602 3603 ret = bpf_iter_udp_realloc_batch(iter, INIT_BATCH_SZ); 3604 if (ret) 3605 bpf_iter_fini_seq_net(priv_data); 3606 3607 return ret; 3608 } 3609 3610 static void bpf_iter_fini_udp(void *priv_data) 3611 { 3612 struct bpf_udp_iter_state *iter = priv_data; 3613 3614 bpf_iter_fini_seq_net(priv_data); 3615 kvfree(iter->batch); 3616 } 3617 3618 static const struct bpf_iter_seq_info udp_seq_info = { 3619 .seq_ops = &bpf_iter_udp_seq_ops, 3620 .init_seq_private = bpf_iter_init_udp, 3621 .fini_seq_private = bpf_iter_fini_udp, 3622 .seq_priv_size = sizeof(struct bpf_udp_iter_state), 3623 }; 3624 3625 static struct bpf_iter_reg udp_reg_info = { 3626 .target = "udp", 3627 .ctx_arg_info_size = 1, 3628 .ctx_arg_info = { 3629 { offsetof(struct bpf_iter__udp, udp_sk), 3630 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED }, 3631 }, 3632 .seq_info = &udp_seq_info, 3633 }; 3634 3635 static void __init bpf_iter_register(void) 3636 { 3637 udp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UDP]; 3638 if (bpf_iter_reg_target(&udp_reg_info)) 3639 pr_warn("Warning: could not register bpf iterator udp\n"); 3640 } 3641 #endif 3642 3643 void __init udp_init(void) 3644 { 3645 unsigned long limit; 3646 unsigned int i; 3647 3648 udp_table_init(&udp_table, "UDP"); 3649 limit = nr_free_buffer_pages() / 8; 3650 limit = max(limit, 128UL); 3651 sysctl_udp_mem[0] = limit / 4 * 3; 3652 sysctl_udp_mem[1] = limit; 3653 sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2; 3654 3655 /* 16 spinlocks per cpu */ 3656 udp_busylocks_log = ilog2(nr_cpu_ids) + 4; 3657 udp_busylocks = kmalloc(sizeof(spinlock_t) << udp_busylocks_log, 3658 GFP_KERNEL); 3659 if (!udp_busylocks) 3660 panic("UDP: failed to alloc udp_busylocks\n"); 3661 for (i = 0; i < (1U << udp_busylocks_log); i++) 3662 spin_lock_init(udp_busylocks + i); 3663 3664 if (register_pernet_subsys(&udp_sysctl_ops)) 3665 panic("UDP: failed to init sysctl parameters.\n"); 3666 3667 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) 3668 bpf_iter_register(); 3669 #endif 3670 } 3671