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