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