1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Definitions for the UDP module. 7 * 8 * Version: @(#)udp.h 1.0.2 05/07/93 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * 13 * Fixes: 14 * Alan Cox : Turned on udp checksums. I don't want to 15 * chase 'memory corruption' bugs that aren't! 16 * 17 * This program is free software; you can redistribute it and/or 18 * modify it under the terms of the GNU General Public License 19 * as published by the Free Software Foundation; either version 20 * 2 of the License, or (at your option) any later version. 21 */ 22 #ifndef _UDP_H 23 #define _UDP_H 24 25 #include <linux/list.h> 26 #include <linux/bug.h> 27 #include <net/inet_sock.h> 28 #include <net/sock.h> 29 #include <net/snmp.h> 30 #include <net/ip.h> 31 #include <linux/ipv6.h> 32 #include <linux/seq_file.h> 33 #include <linux/poll.h> 34 35 /** 36 * struct udp_skb_cb - UDP(-Lite) private variables 37 * 38 * @header: private variables used by IPv4/IPv6 39 * @cscov: checksum coverage length (UDP-Lite only) 40 * @partial_cov: if set indicates partial csum coverage 41 */ 42 struct udp_skb_cb { 43 union { 44 struct inet_skb_parm h4; 45 #if IS_ENABLED(CONFIG_IPV6) 46 struct inet6_skb_parm h6; 47 #endif 48 } header; 49 __u16 cscov; 50 __u8 partial_cov; 51 }; 52 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb)) 53 54 /** 55 * struct udp_hslot - UDP hash slot 56 * 57 * @head: head of list of sockets 58 * @count: number of sockets in 'head' list 59 * @lock: spinlock protecting changes to head/count 60 */ 61 struct udp_hslot { 62 struct hlist_head head; 63 int count; 64 spinlock_t lock; 65 } __attribute__((aligned(2 * sizeof(long)))); 66 67 /** 68 * struct udp_table - UDP table 69 * 70 * @hash: hash table, sockets are hashed on (local port) 71 * @hash2: hash table, sockets are hashed on (local port, local address) 72 * @mask: number of slots in hash tables, minus 1 73 * @log: log2(number of slots in hash table) 74 */ 75 struct udp_table { 76 struct udp_hslot *hash; 77 struct udp_hslot *hash2; 78 unsigned int mask; 79 unsigned int log; 80 }; 81 extern struct udp_table udp_table; 82 void udp_table_init(struct udp_table *, const char *); 83 static inline struct udp_hslot *udp_hashslot(struct udp_table *table, 84 struct net *net, unsigned int num) 85 { 86 return &table->hash[udp_hashfn(net, num, table->mask)]; 87 } 88 /* 89 * For secondary hash, net_hash_mix() is performed before calling 90 * udp_hashslot2(), this explains difference with udp_hashslot() 91 */ 92 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table, 93 unsigned int hash) 94 { 95 return &table->hash2[hash & table->mask]; 96 } 97 98 extern struct proto udp_prot; 99 100 extern atomic_long_t udp_memory_allocated; 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 */ 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 } 118 119 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 */ 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 } 140 141 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 } 151 152 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); 160 161 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)(struct sk_buff *skb, __be16 sport, 171 __be16 dport); 172 173 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb, 174 struct udphdr *uh, udp_lookup_t lookup); 175 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup); 176 177 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, 178 netdev_features_t features); 179 180 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb) 181 { 182 struct udphdr *uh; 183 unsigned int hlen, off; 184 185 off = skb_gro_offset(skb); 186 hlen = off + sizeof(*uh); 187 uh = skb_gro_header_fast(skb, off); 188 if (skb_gro_header_hard(skb, hlen)) 189 uh = skb_gro_header_slow(skb, hlen, off); 190 191 return uh; 192 } 193 194 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */ 195 static inline int udp_lib_hash(struct sock *sk) 196 { 197 BUG(); 198 return 0; 199 } 200 201 void udp_lib_unhash(struct sock *sk); 202 void udp_lib_rehash(struct sock *sk, u16 new_hash); 203 204 static inline void udp_lib_close(struct sock *sk, long timeout) 205 { 206 sk_common_release(sk); 207 } 208 209 int udp_lib_get_port(struct sock *sk, unsigned short snum, 210 unsigned int hash2_nulladdr); 211 212 u32 udp_flow_hashrnd(void); 213 214 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb, 215 int min, int max, bool use_eth) 216 { 217 u32 hash; 218 219 if (min >= max) { 220 /* Use default range */ 221 inet_get_local_port_range(net, &min, &max); 222 } 223 224 hash = skb_get_hash(skb); 225 if (unlikely(!hash)) { 226 if (use_eth) { 227 /* Can't find a normal hash, caller has indicated an 228 * Ethernet packet so use that to compute a hash. 229 */ 230 hash = jhash(skb->data, 2 * ETH_ALEN, 231 (__force u32) skb->protocol); 232 } else { 233 /* Can't derive any sort of hash for the packet, set 234 * to some consistent random value. 235 */ 236 hash = udp_flow_hashrnd(); 237 } 238 } 239 240 /* Since this is being sent on the wire obfuscate hash a bit 241 * to minimize possbility that any useful information to an 242 * attacker is leaked. Only upper 16 bits are relevant in the 243 * computation for 16 bit port value. 244 */ 245 hash ^= hash << 16; 246 247 return htons((((u64) hash * (max - min)) >> 32) + min); 248 } 249 250 static inline int udp_rqueue_get(struct sock *sk) 251 { 252 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit); 253 } 254 255 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if, 256 int dif, int sdif) 257 { 258 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 259 return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept, 260 bound_dev_if, dif, sdif); 261 #else 262 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); 263 #endif 264 } 265 266 /* net/ipv4/udp.c */ 267 void udp_destruct_sock(struct sock *sk); 268 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); 269 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb); 270 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb); 271 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 272 int noblock, int *peeked, int *off, int *err); 273 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, 274 int noblock, int *err) 275 { 276 int peeked, off = 0; 277 278 return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err); 279 } 280 281 int udp_v4_early_demux(struct sk_buff *skb); 282 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); 283 int udp_get_port(struct sock *sk, unsigned short snum, 284 int (*saddr_cmp)(const struct sock *, 285 const struct sock *)); 286 int udp_err(struct sk_buff *, u32); 287 int udp_abort(struct sock *sk, int err); 288 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 289 int udp_push_pending_frames(struct sock *sk); 290 void udp_flush_pending_frames(struct sock *sk); 291 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size); 292 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 293 int udp_rcv(struct sk_buff *skb); 294 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); 295 int udp_init_sock(struct sock *sk); 296 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 297 int __udp_disconnect(struct sock *sk, int flags); 298 int udp_disconnect(struct sock *sk, int flags); 299 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait); 300 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 301 netdev_features_t features, 302 bool is_ipv6); 303 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 304 char __user *optval, int __user *optlen); 305 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 306 char __user *optval, unsigned int optlen, 307 int (*push_pending_frames)(struct sock *)); 308 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 309 __be32 daddr, __be16 dport, int dif); 310 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 311 __be32 daddr, __be16 dport, int dif, int sdif, 312 struct udp_table *tbl, struct sk_buff *skb); 313 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, 314 __be16 sport, __be16 dport); 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); 319 struct 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, int sdif, struct udp_table *tbl, 323 struct sk_buff *skb); 324 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, 325 __be16 sport, __be16 dport); 326 327 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid 328 * possibly multiple cache miss on dequeue() 329 */ 330 struct udp_dev_scratch { 331 /* skb->truesize and the stateless bit are embedded in a single field; 332 * do not use a bitfield since the compiler emits better/smaller code 333 * this way 334 */ 335 u32 _tsize_state; 336 337 #if BITS_PER_LONG == 64 338 /* len and the bit needed to compute skb_csum_unnecessary 339 * will be on cold cache lines at recvmsg time. 340 * skb->len can be stored on 16 bits since the udp header has been 341 * already validated and pulled. 342 */ 343 u16 len; 344 bool is_linear; 345 bool csum_unnecessary; 346 #endif 347 }; 348 349 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb) 350 { 351 return (struct udp_dev_scratch *)&skb->dev_scratch; 352 } 353 354 #if BITS_PER_LONG == 64 355 static inline unsigned int udp_skb_len(struct sk_buff *skb) 356 { 357 return udp_skb_scratch(skb)->len; 358 } 359 360 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 361 { 362 return udp_skb_scratch(skb)->csum_unnecessary; 363 } 364 365 static inline bool udp_skb_is_linear(struct sk_buff *skb) 366 { 367 return udp_skb_scratch(skb)->is_linear; 368 } 369 370 #else 371 static inline unsigned int udp_skb_len(struct sk_buff *skb) 372 { 373 return skb->len; 374 } 375 376 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 377 { 378 return skb_csum_unnecessary(skb); 379 } 380 381 static inline bool udp_skb_is_linear(struct sk_buff *skb) 382 { 383 return !skb_is_nonlinear(skb); 384 } 385 #endif 386 387 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, 388 struct iov_iter *to) 389 { 390 int n; 391 392 n = copy_to_iter(skb->data + off, len, to); 393 if (n == len) 394 return 0; 395 396 iov_iter_revert(to, n); 397 return -EFAULT; 398 } 399 400 /* 401 * SNMP statistics for UDP and UDP-Lite 402 */ 403 #define UDP_INC_STATS(net, field, is_udplite) do { \ 404 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 405 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 406 #define __UDP_INC_STATS(net, field, is_udplite) do { \ 407 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 408 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 409 410 #define __UDP6_INC_STATS(net, field, is_udplite) do { \ 411 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\ 412 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 413 } while(0) 414 #define UDP6_INC_STATS(net, field, __lite) do { \ 415 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \ 416 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 417 } while(0) 418 419 #if IS_ENABLED(CONFIG_IPV6) 420 #define __UDPX_MIB(sk, ipv4) \ 421 ({ \ 422 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 423 sock_net(sk)->mib.udp_statistics) : \ 424 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \ 425 sock_net(sk)->mib.udp_stats_in6); \ 426 }) 427 #else 428 #define __UDPX_MIB(sk, ipv4) \ 429 ({ \ 430 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \ 431 sock_net(sk)->mib.udp_statistics; \ 432 }) 433 #endif 434 435 #define __UDPX_INC_STATS(sk, field) \ 436 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field) 437 438 #ifdef CONFIG_PROC_FS 439 struct udp_seq_afinfo { 440 sa_family_t family; 441 struct udp_table *udp_table; 442 }; 443 444 struct udp_iter_state { 445 struct seq_net_private p; 446 int bucket; 447 }; 448 449 void *udp_seq_start(struct seq_file *seq, loff_t *pos); 450 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 451 void udp_seq_stop(struct seq_file *seq, void *v); 452 453 extern const struct seq_operations udp_seq_ops; 454 extern const struct seq_operations udp6_seq_ops; 455 456 int udp4_proc_init(void); 457 void udp4_proc_exit(void); 458 #endif /* CONFIG_PROC_FS */ 459 460 int udpv4_offload_init(void); 461 462 void udp_init(void); 463 464 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key); 465 void udp_encap_enable(void); 466 #if IS_ENABLED(CONFIG_IPV6) 467 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key); 468 void udpv6_encap_enable(void); 469 #endif 470 471 static inline struct sk_buff *udp_rcv_segment(struct sock *sk, 472 struct sk_buff *skb, bool ipv4) 473 { 474 struct sk_buff *segs; 475 476 /* the GSO CB lays after the UDP one, no need to save and restore any 477 * CB fragment 478 */ 479 segs = __skb_gso_segment(skb, NETIF_F_SG, false); 480 if (unlikely(IS_ERR_OR_NULL(segs))) { 481 int segs_nr = skb_shinfo(skb)->gso_segs; 482 483 atomic_add(segs_nr, &sk->sk_drops); 484 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr); 485 kfree_skb(skb); 486 return NULL; 487 } 488 489 consume_skb(skb); 490 return segs; 491 } 492 493 #endif /* _UDP_H */ 494