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 /* net/ipv4/udp.c */ 256 void udp_destruct_sock(struct sock *sk); 257 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); 258 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb); 259 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb); 260 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 261 int noblock, int *peeked, int *off, int *err); 262 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, 263 int noblock, int *err) 264 { 265 int peeked, off = 0; 266 267 return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err); 268 } 269 270 int udp_v4_early_demux(struct sk_buff *skb); 271 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); 272 int udp_get_port(struct sock *sk, unsigned short snum, 273 int (*saddr_cmp)(const struct sock *, 274 const struct sock *)); 275 void udp_err(struct sk_buff *, u32); 276 int udp_abort(struct sock *sk, int err); 277 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 278 int udp_push_pending_frames(struct sock *sk); 279 void udp_flush_pending_frames(struct sock *sk); 280 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size); 281 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 282 int udp_rcv(struct sk_buff *skb); 283 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); 284 int udp_init_sock(struct sock *sk); 285 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 286 int __udp_disconnect(struct sock *sk, int flags); 287 int udp_disconnect(struct sock *sk, int flags); 288 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait); 289 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 290 netdev_features_t features, 291 bool is_ipv6); 292 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 293 char __user *optval, int __user *optlen); 294 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 295 char __user *optval, unsigned int optlen, 296 int (*push_pending_frames)(struct sock *)); 297 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 298 __be32 daddr, __be16 dport, int dif); 299 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 300 __be32 daddr, __be16 dport, int dif, int sdif, 301 struct udp_table *tbl, struct sk_buff *skb); 302 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, 303 __be16 sport, __be16 dport); 304 struct sock *udp6_lib_lookup(struct net *net, 305 const struct in6_addr *saddr, __be16 sport, 306 const struct in6_addr *daddr, __be16 dport, 307 int dif); 308 struct sock *__udp6_lib_lookup(struct net *net, 309 const struct in6_addr *saddr, __be16 sport, 310 const struct in6_addr *daddr, __be16 dport, 311 int dif, int sdif, struct udp_table *tbl, 312 struct sk_buff *skb); 313 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, 314 __be16 sport, __be16 dport); 315 316 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid 317 * possibly multiple cache miss on dequeue() 318 */ 319 struct udp_dev_scratch { 320 /* skb->truesize and the stateless bit are embedded in a single field; 321 * do not use a bitfield since the compiler emits better/smaller code 322 * this way 323 */ 324 u32 _tsize_state; 325 326 #if BITS_PER_LONG == 64 327 /* len and the bit needed to compute skb_csum_unnecessary 328 * will be on cold cache lines at recvmsg time. 329 * skb->len can be stored on 16 bits since the udp header has been 330 * already validated and pulled. 331 */ 332 u16 len; 333 bool is_linear; 334 bool csum_unnecessary; 335 #endif 336 }; 337 338 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb) 339 { 340 return (struct udp_dev_scratch *)&skb->dev_scratch; 341 } 342 343 #if BITS_PER_LONG == 64 344 static inline unsigned int udp_skb_len(struct sk_buff *skb) 345 { 346 return udp_skb_scratch(skb)->len; 347 } 348 349 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 350 { 351 return udp_skb_scratch(skb)->csum_unnecessary; 352 } 353 354 static inline bool udp_skb_is_linear(struct sk_buff *skb) 355 { 356 return udp_skb_scratch(skb)->is_linear; 357 } 358 359 #else 360 static inline unsigned int udp_skb_len(struct sk_buff *skb) 361 { 362 return skb->len; 363 } 364 365 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 366 { 367 return skb_csum_unnecessary(skb); 368 } 369 370 static inline bool udp_skb_is_linear(struct sk_buff *skb) 371 { 372 return !skb_is_nonlinear(skb); 373 } 374 #endif 375 376 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, 377 struct iov_iter *to) 378 { 379 int n; 380 381 n = copy_to_iter(skb->data + off, len, to); 382 if (n == len) 383 return 0; 384 385 iov_iter_revert(to, n); 386 return -EFAULT; 387 } 388 389 /* 390 * SNMP statistics for UDP and UDP-Lite 391 */ 392 #define UDP_INC_STATS(net, field, is_udplite) do { \ 393 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 394 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 395 #define __UDP_INC_STATS(net, field, is_udplite) do { \ 396 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 397 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 398 399 #define __UDP6_INC_STATS(net, field, is_udplite) do { \ 400 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\ 401 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 402 } while(0) 403 #define UDP6_INC_STATS(net, field, __lite) do { \ 404 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \ 405 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 406 } while(0) 407 408 #if IS_ENABLED(CONFIG_IPV6) 409 #define __UDPX_INC_STATS(sk, field) \ 410 do { \ 411 if ((sk)->sk_family == AF_INET) \ 412 __UDP_INC_STATS(sock_net(sk), field, 0); \ 413 else \ 414 __UDP6_INC_STATS(sock_net(sk), field, 0); \ 415 } while (0) 416 #else 417 #define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0) 418 #endif 419 420 #ifdef CONFIG_PROC_FS 421 struct udp_seq_afinfo { 422 sa_family_t family; 423 struct udp_table *udp_table; 424 }; 425 426 struct udp_iter_state { 427 struct seq_net_private p; 428 int bucket; 429 }; 430 431 void *udp_seq_start(struct seq_file *seq, loff_t *pos); 432 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos); 433 void udp_seq_stop(struct seq_file *seq, void *v); 434 435 extern const struct seq_operations udp_seq_ops; 436 extern const struct seq_operations udp6_seq_ops; 437 438 int udp4_proc_init(void); 439 void udp4_proc_exit(void); 440 #endif /* CONFIG_PROC_FS */ 441 442 int udpv4_offload_init(void); 443 444 void udp_init(void); 445 446 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key); 447 void udp_encap_enable(void); 448 #if IS_ENABLED(CONFIG_IPV6) 449 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key); 450 void udpv6_encap_enable(void); 451 #endif 452 453 #endif /* _UDP_H */ 454