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 sk_buff **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 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb) 178 { 179 struct udphdr *uh; 180 unsigned int hlen, off; 181 182 off = skb_gro_offset(skb); 183 hlen = off + sizeof(*uh); 184 uh = skb_gro_header_fast(skb, off); 185 if (skb_gro_header_hard(skb, hlen)) 186 uh = skb_gro_header_slow(skb, hlen, off); 187 188 return uh; 189 } 190 191 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */ 192 static inline int udp_lib_hash(struct sock *sk) 193 { 194 BUG(); 195 return 0; 196 } 197 198 void udp_lib_unhash(struct sock *sk); 199 void udp_lib_rehash(struct sock *sk, u16 new_hash); 200 201 static inline void udp_lib_close(struct sock *sk, long timeout) 202 { 203 sk_common_release(sk); 204 } 205 206 int udp_lib_get_port(struct sock *sk, unsigned short snum, 207 unsigned int hash2_nulladdr); 208 209 u32 udp_flow_hashrnd(void); 210 211 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb, 212 int min, int max, bool use_eth) 213 { 214 u32 hash; 215 216 if (min >= max) { 217 /* Use default range */ 218 inet_get_local_port_range(net, &min, &max); 219 } 220 221 hash = skb_get_hash(skb); 222 if (unlikely(!hash)) { 223 if (use_eth) { 224 /* Can't find a normal hash, caller has indicated an 225 * Ethernet packet so use that to compute a hash. 226 */ 227 hash = jhash(skb->data, 2 * ETH_ALEN, 228 (__force u32) skb->protocol); 229 } else { 230 /* Can't derive any sort of hash for the packet, set 231 * to some consistent random value. 232 */ 233 hash = udp_flow_hashrnd(); 234 } 235 } 236 237 /* Since this is being sent on the wire obfuscate hash a bit 238 * to minimize possbility that any useful information to an 239 * attacker is leaked. Only upper 16 bits are relevant in the 240 * computation for 16 bit port value. 241 */ 242 hash ^= hash << 16; 243 244 return htons((((u64) hash * (max - min)) >> 32) + min); 245 } 246 247 /* net/ipv4/udp.c */ 248 void udp_destruct_sock(struct sock *sk); 249 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); 250 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb); 251 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb); 252 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 253 int noblock, int *peeked, int *off, int *err); 254 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags, 255 int noblock, int *err) 256 { 257 int peeked, off = 0; 258 259 return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err); 260 } 261 262 void udp_v4_early_demux(struct sk_buff *skb); 263 void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst); 264 int udp_get_port(struct sock *sk, unsigned short snum, 265 int (*saddr_cmp)(const struct sock *, 266 const struct sock *)); 267 void udp_err(struct sk_buff *, u32); 268 int udp_abort(struct sock *sk, int err); 269 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); 270 int udp_push_pending_frames(struct sock *sk); 271 void udp_flush_pending_frames(struct sock *sk); 272 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); 273 int udp_rcv(struct sk_buff *skb); 274 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); 275 int udp_init_sock(struct sock *sk); 276 int __udp_disconnect(struct sock *sk, int flags); 277 int udp_disconnect(struct sock *sk, int flags); 278 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait); 279 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 280 netdev_features_t features, 281 bool is_ipv6); 282 int udp_lib_getsockopt(struct sock *sk, int level, int optname, 283 char __user *optval, int __user *optlen); 284 int udp_lib_setsockopt(struct sock *sk, int level, int optname, 285 char __user *optval, unsigned int optlen, 286 int (*push_pending_frames)(struct sock *)); 287 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 288 __be32 daddr, __be16 dport, int dif); 289 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, 290 __be32 daddr, __be16 dport, int dif, 291 struct udp_table *tbl, struct sk_buff *skb); 292 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, 293 __be16 sport, __be16 dport); 294 struct sock *udp6_lib_lookup(struct net *net, 295 const struct in6_addr *saddr, __be16 sport, 296 const struct in6_addr *daddr, __be16 dport, 297 int dif); 298 struct sock *__udp6_lib_lookup(struct net *net, 299 const struct in6_addr *saddr, __be16 sport, 300 const struct in6_addr *daddr, __be16 dport, 301 int dif, struct udp_table *tbl, 302 struct sk_buff *skb); 303 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, 304 __be16 sport, __be16 dport); 305 306 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid 307 * possibly multiple cache miss on dequeue() 308 */ 309 struct udp_dev_scratch { 310 /* skb->truesize and the stateless bit are embedded in a single field; 311 * do not use a bitfield since the compiler emits better/smaller code 312 * this way 313 */ 314 u32 _tsize_state; 315 316 #if BITS_PER_LONG == 64 317 /* len and the bit needed to compute skb_csum_unnecessary 318 * will be on cold cache lines at recvmsg time. 319 * skb->len can be stored on 16 bits since the udp header has been 320 * already validated and pulled. 321 */ 322 u16 len; 323 bool is_linear; 324 bool csum_unnecessary; 325 #endif 326 }; 327 328 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb) 329 { 330 return (struct udp_dev_scratch *)&skb->dev_scratch; 331 } 332 333 #if BITS_PER_LONG == 64 334 static inline unsigned int udp_skb_len(struct sk_buff *skb) 335 { 336 return udp_skb_scratch(skb)->len; 337 } 338 339 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 340 { 341 return udp_skb_scratch(skb)->csum_unnecessary; 342 } 343 344 static inline bool udp_skb_is_linear(struct sk_buff *skb) 345 { 346 return udp_skb_scratch(skb)->is_linear; 347 } 348 349 #else 350 static inline unsigned int udp_skb_len(struct sk_buff *skb) 351 { 352 return skb->len; 353 } 354 355 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) 356 { 357 return skb_csum_unnecessary(skb); 358 } 359 360 static inline bool udp_skb_is_linear(struct sk_buff *skb) 361 { 362 return !skb_is_nonlinear(skb); 363 } 364 #endif 365 366 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, 367 struct iov_iter *to) 368 { 369 int n, copy = len - off; 370 371 n = copy_to_iter(skb->data + off, copy, to); 372 if (n == copy) 373 return 0; 374 375 return -EFAULT; 376 } 377 378 /* 379 * SNMP statistics for UDP and UDP-Lite 380 */ 381 #define UDP_INC_STATS(net, field, is_udplite) do { \ 382 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 383 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 384 #define __UDP_INC_STATS(net, field, is_udplite) do { \ 385 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \ 386 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0) 387 388 #define __UDP6_INC_STATS(net, field, is_udplite) do { \ 389 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\ 390 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 391 } while(0) 392 #define UDP6_INC_STATS(net, field, __lite) do { \ 393 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \ 394 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \ 395 } while(0) 396 397 #if IS_ENABLED(CONFIG_IPV6) 398 #define __UDPX_INC_STATS(sk, field) \ 399 do { \ 400 if ((sk)->sk_family == AF_INET) \ 401 __UDP_INC_STATS(sock_net(sk), field, 0); \ 402 else \ 403 __UDP6_INC_STATS(sock_net(sk), field, 0); \ 404 } while (0) 405 #else 406 #define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0) 407 #endif 408 409 /* /proc */ 410 int udp_seq_open(struct inode *inode, struct file *file); 411 412 struct udp_seq_afinfo { 413 char *name; 414 sa_family_t family; 415 struct udp_table *udp_table; 416 const struct file_operations *seq_fops; 417 struct seq_operations seq_ops; 418 }; 419 420 struct udp_iter_state { 421 struct seq_net_private p; 422 sa_family_t family; 423 int bucket; 424 struct udp_table *udp_table; 425 }; 426 427 #ifdef CONFIG_PROC_FS 428 int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo); 429 void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo); 430 431 int udp4_proc_init(void); 432 void udp4_proc_exit(void); 433 #endif 434 435 int udpv4_offload_init(void); 436 437 void udp_init(void); 438 439 void udp_encap_enable(void); 440 #if IS_ENABLED(CONFIG_IPV6) 441 void udpv6_encap_enable(void); 442 #endif 443 444 #endif /* _UDP_H */ 445