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 */ 39struct 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 */ 58struct 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 */ 72struct udp_table { 73 struct udp_hslot *hash; 74 struct udp_hslot *hash2; 75 unsigned int mask; 76 unsigned int log; 77}; 78extern struct udp_table udp_table; 79void udp_table_init(struct udp_table *, const char *); 80static 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 */ 89static inline struct udp_hslot *udp_hashslot2(struct udp_table *table, 90 unsigned int hash) 91{ 92 return &table->hash2[hash & table->mask]; 93} 94 95extern struct proto udp_prot; 96 97extern atomic_long_t udp_memory_allocated; 98 99/* sysctl variables for udp */ 100extern long sysctl_udp_mem[3]; 101extern int sysctl_udp_rmem_min; 102extern int sysctl_udp_wmem_min; 103 104struct sk_buff; 105 106/* 107 * Generic checksumming routines for UDP(-Lite) v4 and v6 108 */ 109static 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 116static 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 */ 128static 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 138static 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 149static 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 155void udp_set_csum(bool nocheck, struct sk_buff *skb, 156 __be32 saddr, __be32 daddr, int len); 157 158static 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 167typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport, 168 __be16 dport); 169 170INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_head *, 171 struct sk_buff *)); 172INDIRECT_CALLABLE_DECLARE(int udp4_gro_complete(struct sk_buff *, int)); 173INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *, 174 struct sk_buff *)); 175INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int)); 176struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb, 177 struct udphdr *uh, struct sock *sk); 178int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup); 179void udp_v6_early_demux(struct sk_buff *skb); 180 181struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, 182 netdev_features_t features, bool is_ipv6); 183 184static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb) 185{ 186 struct udphdr *uh; 187 unsigned int hlen, off; 188 189 off = skb_gro_offset(skb); 190 hlen = off + sizeof(*uh); 191 uh = skb_gro_header_fast(skb, off); 192 if (skb_gro_header_hard(skb, hlen)) 193 uh = skb_gro_header_slow(skb, hlen, off); 194 195 return uh; 196} 197 198/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */ 199static inline int udp_lib_hash(struct sock *sk) 200{ 201 BUG(); 202 return 0; 203} 204 205void udp_lib_unhash(struct sock *sk); 206void udp_lib_rehash(struct sock *sk, u16 new_hash); 207 208static inline void udp_lib_close(struct sock *sk, long timeout) 209{ 210 sk_common_release(sk); 211} 212 213int udp_lib_get_port(struct sock *sk, unsigned short snum, 214 unsigned int hash2_nulladdr); 215 216u32 udp_flow_hashrnd(void); 217 218static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb, 219 int min, int max, bool use_eth) 220{ 221 u32 hash; 222 223 if (min >= max) { 224 /* Use default range */ 225 inet_get_local_port_range(net, &min, &max); 226 } 227 228 hash = skb_get_hash(skb); 229 if (unlikely(!hash)) { 230 if (use_eth) { 231 /* Can't find a normal hash, caller has indicated an 232 * Ethernet packet so use that to compute a hash. 233 */ 234 hash = jhash(skb->data, 2 * ETH_ALEN, 235 (__force u32) skb->protocol); 236 } else { 237 /* Can't derive any sort of hash for the packet, set 238 * to some consistent random value. 239 */ 240 hash = udp_flow_hashrnd(); 241 } 242 } 243 244 /* Since this is being sent on the wire obfuscate hash a bit 245 * to minimize possbility that any useful information to an 246 * attacker is leaked. Only upper 16 bits are relevant in the 247 * computation for 16 bit port value. 248 */ 249 hash ^= hash << 16; 250 251 return htons((((u64) hash * (max - min)) >> 32) + min); 252} 253 254static inline int udp_rqueue_get(struct sock *sk) 255{ 256 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit); 257} 258 259static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if, 260 int dif, int sdif) 261{ 262#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 263 return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept), 264 bound_dev_if, dif, sdif); 265#else 266 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); 267#endif 268} 269 270/* net/ipv4/udp.c */ 271void udp_destruct_common(struct sock *sk); 272void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); 273int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb); 274void udp_skb_destructor(struct sock *sk, struct sk_buff *skb); 275struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 276 int noblock, int *off, int *err); 277static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, 278 int noblock, int *err) 279{ 280 int off = 0; 281 282 return __skb_recv_udp(sk, flags, noblock, &off, err); 283} 284 285int udp_v4_early_demux(struct sk_buff *skb); 286bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); 287int udp_get_port(struct sock *sk, unsigned short snum, 288 int (*saddr_cmp)(const struct sock *, 289 const struct sock *)); 290int udp_err(struct sk_buff *, u32); 291int udp_abort(struct sock *sk, int err); 292int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 293int udp_push_pending_frames(struct sock *sk); 294void udp_flush_pending_frames(struct sock *sk); 295int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size); 296void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 297int udp_rcv(struct sk_buff *skb); 298int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); 299int udp_init_sock(struct sock *sk); 300int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 301int __udp_disconnect(struct sock *sk, int flags); 302int udp_disconnect(struct sock *sk, int flags); 303__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait); 304struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 305 netdev_features_t features, 306 bool is_ipv6); 307int udp_lib_getsockopt(struct sock *sk, int level, int optname, 308 char __user *optval, int __user *optlen); 309int udp_lib_setsockopt(struct sock *sk, int level, int optname, 310 sockptr_t optval, unsigned int optlen, 311 int (*push_pending_frames)(struct sock *)); 312struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 313 __be32 daddr, __be16 dport, int dif); 314struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 315 __be32 daddr, __be16 dport, int dif, int sdif, 316 struct udp_table *tbl, struct sk_buff *skb); 317struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, 318 __be16 sport, __be16 dport); 319struct sock *udp6_lib_lookup(struct net *net, 320 const struct in6_addr *saddr, __be16 sport, 321 const struct in6_addr *daddr, __be16 dport, 322 int dif); 323struct sock *__udp6_lib_lookup(struct net *net, 324 const struct in6_addr *saddr, __be16 sport, 325 const struct in6_addr *daddr, __be16 dport, 326 int dif, int sdif, struct udp_table *tbl, 327 struct sk_buff *skb); 328struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, 329 __be16 sport, __be16 dport); 330 331/* UDP uses skb->dev_scratch to cache as much information as possible and avoid 332 * possibly multiple cache miss on dequeue() 333 */ 334struct udp_dev_scratch { 335 /* skb->truesize and the stateless bit are embedded in a single field; 336 * do not use a bitfield since the compiler emits better/smaller code 337 * this way 338 */ 339 u32 _tsize_state; 340 341#if BITS_PER_LONG == 64 342 /* len and the bit needed to compute skb_csum_unnecessary 343 * will be on cold cache lines at recvmsg time. 344 * skb->len can be stored on 16 bits since the udp header has been 345 * already validated and pulled. 346 */ 347 u16 len; 348 bool is_linear; 349 bool csum_unnecessary; 350#endif 351}; 352 353static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb) 354{ 355 return (struct udp_dev_scratch *)&skb->dev_scratch; 356} 357 358#if BITS_PER_LONG == 64 359static inline unsigned int udp_skb_len(struct sk_buff *skb) 360{ 361 return udp_skb_scratch(skb)->len; 362} 363 364static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 365{ 366 return udp_skb_scratch(skb)->csum_unnecessary; 367} 368 369static inline bool udp_skb_is_linear(struct sk_buff *skb) 370{ 371 return udp_skb_scratch(skb)->is_linear; 372} 373 374#else 375static inline unsigned int udp_skb_len(struct sk_buff *skb) 376{ 377 return skb->len; 378} 379 380static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 381{ 382 return skb_csum_unnecessary(skb); 383} 384 385static inline bool udp_skb_is_linear(struct sk_buff *skb) 386{ 387 return !skb_is_nonlinear(skb); 388} 389#endif 390 391static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, 392 struct iov_iter *to) 393{ 394 int n; 395 396 n = copy_to_iter(skb->data + off, len, to); 397 if (n == len) 398 return 0; 399 400 iov_iter_revert(to, n); 401 return -EFAULT; 402} 403 404/* 405 * SNMP statistics for UDP and UDP-Lite 406 */ 407#define UDP_INC_STATS(net, field, is_udplite) do { \ 408 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 409 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 410#define __UDP_INC_STATS(net, field, is_udplite) do { \ 411 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 412 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 413 414#define __UDP6_INC_STATS(net, field, is_udplite) do { \ 415 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\ 416 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 417} while(0) 418#define UDP6_INC_STATS(net, field, __lite) do { \ 419 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \ 420 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 421} while(0) 422 423#if IS_ENABLED(CONFIG_IPV6) 424#define __UDPX_MIB(sk, ipv4) \ 425({ \ 426 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 427 sock_net(sk)->mib.udp_statistics) : \ 428 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \ 429 sock_net(sk)->mib.udp_stats_in6); \ 430}) 431#else 432#define __UDPX_MIB(sk, ipv4) \ 433({ \ 434 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 435 sock_net(sk)->mib.udp_statistics; \ 436}) 437#endif 438 439#define __UDPX_INC_STATS(sk, field) \ 440 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field) 441 442#ifdef CONFIG_PROC_FS 443struct udp_seq_afinfo { 444 sa_family_t family; 445 struct udp_table *udp_table; 446}; 447 448struct udp_iter_state { 449 struct seq_net_private p; 450 int bucket; 451 struct udp_seq_afinfo *bpf_seq_afinfo; 452}; 453 454void *udp_seq_start(struct seq_file *seq, loff_t *pos); 455void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 456void udp_seq_stop(struct seq_file *seq, void *v); 457 458extern const struct seq_operations udp_seq_ops; 459extern const struct seq_operations udp6_seq_ops; 460 461int udp4_proc_init(void); 462void udp4_proc_exit(void); 463#endif /* CONFIG_PROC_FS */ 464 465int udpv4_offload_init(void); 466 467void udp_init(void); 468 469DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key); 470void udp_encap_enable(void); 471void udp_encap_disable(void); 472#if IS_ENABLED(CONFIG_IPV6) 473DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key); 474void udpv6_encap_enable(void); 475#endif 476 477static inline struct sk_buff *udp_rcv_segment(struct sock *sk, 478 struct sk_buff *skb, bool ipv4) 479{ 480 netdev_features_t features = NETIF_F_SG; 481 struct sk_buff *segs; 482 483 /* Avoid csum recalculation by skb_segment unless userspace explicitly 484 * asks for the final checksum values 485 */ 486 if (!inet_get_convert_csum(sk)) 487 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM; 488 489 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or 490 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial 491 * packets in udp_gro_complete_segment. As does UDP GSO, verified by 492 * udp_send_skb. But when those packets are looped in dev_loopback_xmit 493 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY. 494 * Reset in this specific case, where PARTIAL is both correct and 495 * required. 496 */ 497 if (skb->pkt_type == PACKET_LOOPBACK) 498 skb->ip_summed = CHECKSUM_PARTIAL; 499 500 /* the GSO CB lays after the UDP one, no need to save and restore any 501 * CB fragment 502 */ 503 segs = __skb_gso_segment(skb, features, false); 504 if (IS_ERR_OR_NULL(segs)) { 505 int segs_nr = skb_shinfo(skb)->gso_segs; 506 507 atomic_add(segs_nr, &sk->sk_drops); 508 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr); 509 kfree_skb(skb); 510 return NULL; 511 } 512 513 consume_skb(skb); 514 return segs; 515} 516 517#ifdef CONFIG_BPF_STREAM_PARSER 518struct sk_psock; 519struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 520#endif /* BPF_STREAM_PARSER */ 521 522#endif /* _UDP_H */ 523