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(void udp_v6_early_demux(struct sk_buff *)); 171 INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *)); 172 173 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, 174 netdev_features_t features, bool is_ipv6); 175 176 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */ 177 static inline int udp_lib_hash(struct sock *sk) 178 { 179 BUG(); 180 return 0; 181 } 182 183 void udp_lib_unhash(struct sock *sk); 184 void udp_lib_rehash(struct sock *sk, u16 new_hash); 185 186 static inline void udp_lib_close(struct sock *sk, long timeout) 187 { 188 sk_common_release(sk); 189 } 190 191 int udp_lib_get_port(struct sock *sk, unsigned short snum, 192 unsigned int hash2_nulladdr); 193 194 u32 udp_flow_hashrnd(void); 195 196 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb, 197 int min, int max, bool use_eth) 198 { 199 u32 hash; 200 201 if (min >= max) { 202 /* Use default range */ 203 inet_get_local_port_range(net, &min, &max); 204 } 205 206 hash = skb_get_hash(skb); 207 if (unlikely(!hash)) { 208 if (use_eth) { 209 /* Can't find a normal hash, caller has indicated an 210 * Ethernet packet so use that to compute a hash. 211 */ 212 hash = jhash(skb->data, 2 * ETH_ALEN, 213 (__force u32) skb->protocol); 214 } else { 215 /* Can't derive any sort of hash for the packet, set 216 * to some consistent random value. 217 */ 218 hash = udp_flow_hashrnd(); 219 } 220 } 221 222 /* Since this is being sent on the wire obfuscate hash a bit 223 * to minimize possbility that any useful information to an 224 * attacker is leaked. Only upper 16 bits are relevant in the 225 * computation for 16 bit port value. 226 */ 227 hash ^= hash << 16; 228 229 return htons((((u64) hash * (max - min)) >> 32) + min); 230 } 231 232 static inline int udp_rqueue_get(struct sock *sk) 233 { 234 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit); 235 } 236 237 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if, 238 int dif, int sdif) 239 { 240 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 241 return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept, 242 bound_dev_if, dif, sdif); 243 #else 244 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); 245 #endif 246 } 247 248 /* net/ipv4/udp.c */ 249 void udp_destruct_sock(struct sock *sk); 250 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); 251 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb); 252 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb); 253 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off, 254 int *err); 255 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, 256 int *err) 257 { 258 int off = 0; 259 260 return __skb_recv_udp(sk, flags, &off, err); 261 } 262 263 int udp_v4_early_demux(struct sk_buff *skb); 264 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); 265 int udp_get_port(struct sock *sk, unsigned short snum, 266 int (*saddr_cmp)(const struct sock *, 267 const struct sock *)); 268 int udp_err(struct sk_buff *, u32); 269 int udp_abort(struct sock *sk, int err); 270 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 271 int udp_push_pending_frames(struct sock *sk); 272 void udp_flush_pending_frames(struct sock *sk); 273 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size); 274 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 275 int udp_rcv(struct sk_buff *skb); 276 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); 277 int udp_init_sock(struct sock *sk); 278 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 279 int __udp_disconnect(struct sock *sk, int flags); 280 int udp_disconnect(struct sock *sk, int flags); 281 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait); 282 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 283 netdev_features_t features, 284 bool is_ipv6); 285 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 286 char __user *optval, int __user *optlen); 287 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 288 sockptr_t optval, unsigned int optlen, 289 int (*push_pending_frames)(struct sock *)); 290 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 291 __be32 daddr, __be16 dport, int dif); 292 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 293 __be32 daddr, __be16 dport, int dif, int sdif, 294 struct udp_table *tbl, struct sk_buff *skb); 295 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb, 296 __be16 sport, __be16 dport); 297 struct sock *udp6_lib_lookup(struct net *net, 298 const struct in6_addr *saddr, __be16 sport, 299 const struct in6_addr *daddr, __be16 dport, 300 int dif); 301 struct sock *__udp6_lib_lookup(struct net *net, 302 const struct in6_addr *saddr, __be16 sport, 303 const struct in6_addr *daddr, __be16 dport, 304 int dif, int sdif, struct udp_table *tbl, 305 struct sk_buff *skb); 306 struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb, 307 __be16 sport, __be16 dport); 308 int udp_read_sock(struct sock *sk, read_descriptor_t *desc, 309 sk_read_actor_t recv_actor); 310 311 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid 312 * possibly multiple cache miss on dequeue() 313 */ 314 struct udp_dev_scratch { 315 /* skb->truesize and the stateless bit are embedded in a single field; 316 * do not use a bitfield since the compiler emits better/smaller code 317 * this way 318 */ 319 u32 _tsize_state; 320 321 #if BITS_PER_LONG == 64 322 /* len and the bit needed to compute skb_csum_unnecessary 323 * will be on cold cache lines at recvmsg time. 324 * skb->len can be stored on 16 bits since the udp header has been 325 * already validated and pulled. 326 */ 327 u16 len; 328 bool is_linear; 329 bool csum_unnecessary; 330 #endif 331 }; 332 333 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb) 334 { 335 return (struct udp_dev_scratch *)&skb->dev_scratch; 336 } 337 338 #if BITS_PER_LONG == 64 339 static inline unsigned int udp_skb_len(struct sk_buff *skb) 340 { 341 return udp_skb_scratch(skb)->len; 342 } 343 344 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 345 { 346 return udp_skb_scratch(skb)->csum_unnecessary; 347 } 348 349 static inline bool udp_skb_is_linear(struct sk_buff *skb) 350 { 351 return udp_skb_scratch(skb)->is_linear; 352 } 353 354 #else 355 static inline unsigned int udp_skb_len(struct sk_buff *skb) 356 { 357 return skb->len; 358 } 359 360 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 361 { 362 return skb_csum_unnecessary(skb); 363 } 364 365 static inline bool udp_skb_is_linear(struct sk_buff *skb) 366 { 367 return !skb_is_nonlinear(skb); 368 } 369 #endif 370 371 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, 372 struct iov_iter *to) 373 { 374 int n; 375 376 n = copy_to_iter(skb->data + off, len, to); 377 if (n == len) 378 return 0; 379 380 iov_iter_revert(to, n); 381 return -EFAULT; 382 } 383 384 /* 385 * SNMP statistics for UDP and UDP-Lite 386 */ 387 #define UDP_INC_STATS(net, field, is_udplite) do { \ 388 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 389 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 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) 393 394 #define __UDP6_INC_STATS(net, field, is_udplite) do { \ 395 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\ 396 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 397 } while(0) 398 #define UDP6_INC_STATS(net, field, __lite) do { \ 399 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \ 400 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 401 } while(0) 402 403 #if IS_ENABLED(CONFIG_IPV6) 404 #define __UDPX_MIB(sk, ipv4) \ 405 ({ \ 406 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 407 sock_net(sk)->mib.udp_statistics) : \ 408 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \ 409 sock_net(sk)->mib.udp_stats_in6); \ 410 }) 411 #else 412 #define __UDPX_MIB(sk, ipv4) \ 413 ({ \ 414 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 415 sock_net(sk)->mib.udp_statistics; \ 416 }) 417 #endif 418 419 #define __UDPX_INC_STATS(sk, field) \ 420 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field) 421 422 #ifdef CONFIG_PROC_FS 423 struct udp_seq_afinfo { 424 sa_family_t family; 425 struct udp_table *udp_table; 426 }; 427 428 struct udp_iter_state { 429 struct seq_net_private p; 430 int bucket; 431 struct udp_seq_afinfo *bpf_seq_afinfo; 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 struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); 523 int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); 524 #endif 525 526 #endif /* _UDP_H */ 527