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 * Definitions for the UDP module. 8 * 9 * Version: @(#)udp.h 1.0.2 05/07/93 10 * 11 * Authors: Ross Biro 12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 13 * 14 * Fixes: 15 * Alan Cox : Turned on udp checksums. I don't want to 16 * chase 'memory corruption' bugs that aren't! 17 */ 18 #ifndef _UDP_H 19 #define _UDP_H 20 21 #include <linux/list.h> 22 #include <linux/bug.h> 23 #include <net/inet_sock.h> 24 #include <net/sock.h> 25 #include <net/snmp.h> 26 #include <net/ip.h> 27 #include <linux/ipv6.h> 28 #include <linux/seq_file.h> 29 #include <linux/poll.h> 30 #include <linux/indirect_call_wrapper.h> 31 32 /** 33 * struct udp_skb_cb - UDP(-Lite) private variables 34 * 35 * @header: private variables used by IPv4/IPv6 36 * @cscov: checksum coverage length (UDP-Lite only) 37 * @partial_cov: if set indicates partial csum coverage 38 */ 39 struct udp_skb_cb { 40 union { 41 struct inet_skb_parm h4; 42 #if IS_ENABLED(CONFIG_IPV6) 43 struct inet6_skb_parm h6; 44 #endif 45 } header; 46 __u16 cscov; 47 __u8 partial_cov; 48 }; 49 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb)) 50 51 /** 52 * struct udp_hslot - UDP hash slot 53 * 54 * @head: head of list of sockets 55 * @count: number of sockets in 'head' list 56 * @lock: spinlock protecting changes to head/count 57 */ 58 struct udp_hslot { 59 struct hlist_head head; 60 int count; 61 spinlock_t lock; 62 } __attribute__((aligned(2 * sizeof(long)))); 63 64 /** 65 * struct udp_table - UDP table 66 * 67 * @hash: hash table, sockets are hashed on (local port) 68 * @hash2: hash table, sockets are hashed on (local port, local address) 69 * @mask: number of slots in hash tables, minus 1 70 * @log: log2(number of slots in hash table) 71 */ 72 struct udp_table { 73 struct udp_hslot *hash; 74 struct udp_hslot *hash2; 75 unsigned int mask; 76 unsigned int log; 77 }; 78 extern struct udp_table udp_table; 79 void udp_table_init(struct udp_table *, const char *); 80 static inline struct udp_hslot *udp_hashslot(struct udp_table *table, 81 struct net *net, unsigned int num) 82 { 83 return &table->hash[udp_hashfn(net, num, table->mask)]; 84 } 85 /* 86 * For secondary hash, net_hash_mix() is performed before calling 87 * udp_hashslot2(), this explains difference with udp_hashslot() 88 */ 89 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table, 90 unsigned int hash) 91 { 92 return &table->hash2[hash & table->mask]; 93 } 94 95 extern struct proto udp_prot; 96 97 extern atomic_long_t udp_memory_allocated; 98 99 /* sysctl variables for udp */ 100 extern long sysctl_udp_mem[3]; 101 extern int sysctl_udp_rmem_min; 102 extern int sysctl_udp_wmem_min; 103 104 struct sk_buff; 105 106 /* 107 * Generic checksumming routines for UDP(-Lite) v4 and v6 108 */ 109 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb) 110 { 111 return (UDP_SKB_CB(skb)->cscov == skb->len ? 112 __skb_checksum_complete(skb) : 113 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov)); 114 } 115 116 static inline int udp_lib_checksum_complete(struct sk_buff *skb) 117 { 118 return !skb_csum_unnecessary(skb) && 119 __udp_lib_checksum_complete(skb); 120 } 121 122 /** 123 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments 124 * @sk: socket we are writing to 125 * @skb: sk_buff containing the filled-in UDP header 126 * (checksum field must be zeroed out) 127 */ 128 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb) 129 { 130 __wsum csum = csum_partial(skb_transport_header(skb), 131 sizeof(struct udphdr), 0); 132 skb_queue_walk(&sk->sk_write_queue, skb) { 133 csum = csum_add(csum, skb->csum); 134 } 135 return csum; 136 } 137 138 static inline __wsum udp_csum(struct sk_buff *skb) 139 { 140 __wsum csum = csum_partial(skb_transport_header(skb), 141 sizeof(struct udphdr), skb->csum); 142 143 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) { 144 csum = csum_add(csum, skb->csum); 145 } 146 return csum; 147 } 148 149 static inline __sum16 udp_v4_check(int len, __be32 saddr, 150 __be32 daddr, __wsum base) 151 { 152 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base); 153 } 154 155 void udp_set_csum(bool nocheck, struct sk_buff *skb, 156 __be32 saddr, __be32 daddr, int len); 157 158 static inline void udp_csum_pull_header(struct sk_buff *skb) 159 { 160 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE) 161 skb->csum = csum_partial(skb->data, sizeof(struct udphdr), 162 skb->csum); 163 skb_pull_rcsum(skb, sizeof(struct udphdr)); 164 UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr); 165 } 166 167 typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport, 168 __be16 dport); 169 170 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_head *, 171 struct sk_buff *)); 172 INDIRECT_CALLABLE_DECLARE(int udp4_gro_complete(struct sk_buff *, int)); 173 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *, 174 struct sk_buff *)); 175 INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int)); 176 INDIRECT_CALLABLE_DECLARE(void udp_v6_early_demux(struct sk_buff *)); 177 INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *)); 178 179 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb, 180 struct udphdr *uh, struct sock *sk); 181 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup); 182 183 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, 184 netdev_features_t features, bool is_ipv6); 185 186 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb) 187 { 188 struct udphdr *uh; 189 unsigned int hlen, off; 190 191 off = skb_gro_offset(skb); 192 hlen = off + sizeof(*uh); 193 uh = skb_gro_header_fast(skb, off); 194 if (skb_gro_header_hard(skb, hlen)) 195 uh = skb_gro_header_slow(skb, hlen, off); 196 197 return uh; 198 } 199 200 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */ 201 static inline int udp_lib_hash(struct sock *sk) 202 { 203 BUG(); 204 return 0; 205 } 206 207 void udp_lib_unhash(struct sock *sk); 208 void udp_lib_rehash(struct sock *sk, u16 new_hash); 209 210 static inline void udp_lib_close(struct sock *sk, long timeout) 211 { 212 sk_common_release(sk); 213 } 214 215 int udp_lib_get_port(struct sock *sk, unsigned short snum, 216 unsigned int hash2_nulladdr); 217 218 u32 udp_flow_hashrnd(void); 219 220 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb, 221 int min, int max, bool use_eth) 222 { 223 u32 hash; 224 225 if (min >= max) { 226 /* Use default range */ 227 inet_get_local_port_range(net, &min, &max); 228 } 229 230 hash = skb_get_hash(skb); 231 if (unlikely(!hash)) { 232 if (use_eth) { 233 /* Can't find a normal hash, caller has indicated an 234 * Ethernet packet so use that to compute a hash. 235 */ 236 hash = jhash(skb->data, 2 * ETH_ALEN, 237 (__force u32) skb->protocol); 238 } else { 239 /* Can't derive any sort of hash for the packet, set 240 * to some consistent random value. 241 */ 242 hash = udp_flow_hashrnd(); 243 } 244 } 245 246 /* Since this is being sent on the wire obfuscate hash a bit 247 * to minimize possbility that any useful information to an 248 * attacker is leaked. Only upper 16 bits are relevant in the 249 * computation for 16 bit port value. 250 */ 251 hash ^= hash << 16; 252 253 return htons((((u64) hash * (max - min)) >> 32) + min); 254 } 255 256 static inline int udp_rqueue_get(struct sock *sk) 257 { 258 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit); 259 } 260 261 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if, 262 int dif, int sdif) 263 { 264 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 265 return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept, 266 bound_dev_if, dif, sdif); 267 #else 268 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); 269 #endif 270 } 271 272 /* net/ipv4/udp.c */ 273 void udp_destruct_sock(struct sock *sk); 274 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); 275 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb); 276 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb); 277 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 278 int noblock, int *off, int *err); 279 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, 280 int noblock, int *err) 281 { 282 int off = 0; 283 284 return __skb_recv_udp(sk, flags, noblock, &off, err); 285 } 286 287 int udp_v4_early_demux(struct sk_buff *skb); 288 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); 289 int udp_get_port(struct sock *sk, unsigned short snum, 290 int (*saddr_cmp)(const struct sock *, 291 const struct sock *)); 292 int udp_err(struct sk_buff *, u32); 293 int udp_abort(struct sock *sk, int err); 294 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 295 int udp_push_pending_frames(struct sock *sk); 296 void udp_flush_pending_frames(struct sock *sk); 297 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size); 298 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 299 int udp_rcv(struct sk_buff *skb); 300 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); 301 int udp_init_sock(struct sock *sk); 302 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 303 int __udp_disconnect(struct sock *sk, int flags); 304 int udp_disconnect(struct sock *sk, int flags); 305 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait); 306 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 307 netdev_features_t features, 308 bool is_ipv6); 309 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 310 char __user *optval, int __user *optlen); 311 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 312 sockptr_t optval, unsigned int optlen, 313 int (*push_pending_frames)(struct sock *)); 314 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 315 __be32 daddr, __be16 dport, int dif); 316 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 317 __be32 daddr, __be16 dport, int dif, int sdif, 318 struct udp_table *tbl, struct sk_buff *skb); 319 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb, 320 __be16 sport, __be16 dport); 321 struct sock *udp6_lib_lookup(struct net *net, 322 const struct in6_addr *saddr, __be16 sport, 323 const struct in6_addr *daddr, __be16 dport, 324 int dif); 325 struct sock *__udp6_lib_lookup(struct net *net, 326 const struct in6_addr *saddr, __be16 sport, 327 const struct in6_addr *daddr, __be16 dport, 328 int dif, int sdif, struct udp_table *tbl, 329 struct sk_buff *skb); 330 struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb, 331 __be16 sport, __be16 dport); 332 int udp_read_sock(struct sock *sk, read_descriptor_t *desc, 333 sk_read_actor_t recv_actor); 334 335 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid 336 * possibly multiple cache miss on dequeue() 337 */ 338 struct udp_dev_scratch { 339 /* skb->truesize and the stateless bit are embedded in a single field; 340 * do not use a bitfield since the compiler emits better/smaller code 341 * this way 342 */ 343 u32 _tsize_state; 344 345 #if BITS_PER_LONG == 64 346 /* len and the bit needed to compute skb_csum_unnecessary 347 * will be on cold cache lines at recvmsg time. 348 * skb->len can be stored on 16 bits since the udp header has been 349 * already validated and pulled. 350 */ 351 u16 len; 352 bool is_linear; 353 bool csum_unnecessary; 354 #endif 355 }; 356 357 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb) 358 { 359 return (struct udp_dev_scratch *)&skb->dev_scratch; 360 } 361 362 #if BITS_PER_LONG == 64 363 static inline unsigned int udp_skb_len(struct sk_buff *skb) 364 { 365 return udp_skb_scratch(skb)->len; 366 } 367 368 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 369 { 370 return udp_skb_scratch(skb)->csum_unnecessary; 371 } 372 373 static inline bool udp_skb_is_linear(struct sk_buff *skb) 374 { 375 return udp_skb_scratch(skb)->is_linear; 376 } 377 378 #else 379 static inline unsigned int udp_skb_len(struct sk_buff *skb) 380 { 381 return skb->len; 382 } 383 384 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 385 { 386 return skb_csum_unnecessary(skb); 387 } 388 389 static inline bool udp_skb_is_linear(struct sk_buff *skb) 390 { 391 return !skb_is_nonlinear(skb); 392 } 393 #endif 394 395 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, 396 struct iov_iter *to) 397 { 398 int n; 399 400 n = copy_to_iter(skb->data + off, len, to); 401 if (n == len) 402 return 0; 403 404 iov_iter_revert(to, n); 405 return -EFAULT; 406 } 407 408 /* 409 * SNMP statistics for UDP and UDP-Lite 410 */ 411 #define UDP_INC_STATS(net, field, is_udplite) do { \ 412 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 413 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 414 #define __UDP_INC_STATS(net, field, is_udplite) do { \ 415 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 416 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 417 418 #define __UDP6_INC_STATS(net, field, is_udplite) do { \ 419 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\ 420 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 421 } while(0) 422 #define UDP6_INC_STATS(net, field, __lite) do { \ 423 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \ 424 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 425 } while(0) 426 427 #if IS_ENABLED(CONFIG_IPV6) 428 #define __UDPX_MIB(sk, ipv4) \ 429 ({ \ 430 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 431 sock_net(sk)->mib.udp_statistics) : \ 432 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \ 433 sock_net(sk)->mib.udp_stats_in6); \ 434 }) 435 #else 436 #define __UDPX_MIB(sk, ipv4) \ 437 ({ \ 438 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 439 sock_net(sk)->mib.udp_statistics; \ 440 }) 441 #endif 442 443 #define __UDPX_INC_STATS(sk, field) \ 444 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field) 445 446 #ifdef CONFIG_PROC_FS 447 struct udp_seq_afinfo { 448 sa_family_t family; 449 struct udp_table *udp_table; 450 }; 451 452 struct udp_iter_state { 453 struct seq_net_private p; 454 int bucket; 455 struct udp_seq_afinfo *bpf_seq_afinfo; 456 }; 457 458 void *udp_seq_start(struct seq_file *seq, loff_t *pos); 459 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 460 void udp_seq_stop(struct seq_file *seq, void *v); 461 462 extern const struct seq_operations udp_seq_ops; 463 extern const struct seq_operations udp6_seq_ops; 464 465 int udp4_proc_init(void); 466 void udp4_proc_exit(void); 467 #endif /* CONFIG_PROC_FS */ 468 469 int udpv4_offload_init(void); 470 471 void udp_init(void); 472 473 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key); 474 void udp_encap_enable(void); 475 void udp_encap_disable(void); 476 #if IS_ENABLED(CONFIG_IPV6) 477 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key); 478 void udpv6_encap_enable(void); 479 #endif 480 481 static inline struct sk_buff *udp_rcv_segment(struct sock *sk, 482 struct sk_buff *skb, bool ipv4) 483 { 484 netdev_features_t features = NETIF_F_SG; 485 struct sk_buff *segs; 486 487 /* Avoid csum recalculation by skb_segment unless userspace explicitly 488 * asks for the final checksum values 489 */ 490 if (!inet_get_convert_csum(sk)) 491 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM; 492 493 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or 494 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial 495 * packets in udp_gro_complete_segment. As does UDP GSO, verified by 496 * udp_send_skb. But when those packets are looped in dev_loopback_xmit 497 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY. 498 * Reset in this specific case, where PARTIAL is both correct and 499 * required. 500 */ 501 if (skb->pkt_type == PACKET_LOOPBACK) 502 skb->ip_summed = CHECKSUM_PARTIAL; 503 504 /* the GSO CB lays after the UDP one, no need to save and restore any 505 * CB fragment 506 */ 507 segs = __skb_gso_segment(skb, features, false); 508 if (IS_ERR_OR_NULL(segs)) { 509 int segs_nr = skb_shinfo(skb)->gso_segs; 510 511 atomic_add(segs_nr, &sk->sk_drops); 512 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr); 513 kfree_skb(skb); 514 return NULL; 515 } 516 517 consume_skb(skb); 518 return segs; 519 } 520 521 static inline void udp_post_segment_fix_csum(struct sk_buff *skb) 522 { 523 /* UDP-lite can't land here - no GRO */ 524 WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov); 525 526 /* UDP packets generated with UDP_SEGMENT and traversing: 527 * 528 * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx) 529 * 530 * can reach an UDP socket with CHECKSUM_NONE, because 531 * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE. 532 * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will 533 * have a valid checksum, as the GRO engine validates the UDP csum 534 * before the aggregation and nobody strips such info in between. 535 * Instead of adding another check in the tunnel fastpath, we can force 536 * a valid csum after the segmentation. 537 * Additionally fixup the UDP CB. 538 */ 539 UDP_SKB_CB(skb)->cscov = skb->len; 540 if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid) 541 skb->csum_valid = 1; 542 } 543 544 #ifdef CONFIG_BPF_SYSCALL 545 struct sk_psock; 546 struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 547 int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 548 #endif 549 550 #endif /* _UDP_H */ 551