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