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 *);
udp_hashslot(struct udp_table * table,struct net * net,unsigned int num)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 */
udp_hashslot2(struct udp_table * table,unsigned int hash)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 */
__udp_lib_checksum_complete(struct sk_buff * skb)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
udp_lib_checksum_complete(struct sk_buff * skb)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 */
udp_csum_outgoing(struct sock * sk,struct sk_buff * skb)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
udp_csum(struct sk_buff * skb)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
udp_v4_check(int len,__be32 saddr,__be32 daddr,__wsum base)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
udp_csum_pull_header(struct sk_buff * skb)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
udp_gro_udphdr(struct sk_buff * skb)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 */
udp_lib_hash(struct sock * sk)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
udp_lib_close(struct sock * sk,long timeout)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
udp_flow_src_port(struct net * net,struct sk_buff * skb,int min,int max,bool use_eth)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
udp_rqueue_get(struct sock * sk)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);
skb_recv_udp(struct sock * sk,unsigned int flags,int noblock,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
udp_skb_scratch(struct sk_buff * skb)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
udp_skb_len(struct sk_buff * skb)344 static inline unsigned int udp_skb_len(struct sk_buff *skb)
345 {
346 return udp_skb_scratch(skb)->len;
347 }
348
udp_skb_csum_unnecessary(struct sk_buff * skb)349 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
350 {
351 return udp_skb_scratch(skb)->csum_unnecessary;
352 }
353
udp_skb_is_linear(struct sk_buff * skb)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
udp_skb_len(struct sk_buff * skb)360 static inline unsigned int udp_skb_len(struct sk_buff *skb)
361 {
362 return skb->len;
363 }
364
udp_skb_csum_unnecessary(struct sk_buff * skb)365 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
366 {
367 return skb_csum_unnecessary(skb);
368 }
369
udp_skb_is_linear(struct sk_buff * skb)370 static inline bool udp_skb_is_linear(struct sk_buff *skb)
371 {
372 return !skb_is_nonlinear(skb);
373 }
374 #endif
375
copy_linear_skb(struct sk_buff * skb,int len,int off,struct iov_iter * to)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 void udp_encap_enable(void);
447 #if IS_ENABLED(CONFIG_IPV6)
448 void udpv6_encap_enable(void);
449 #endif
450
451 #endif /* _UDP_H */
452
