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 void udp_v6_early_demux(struct sk_buff *skb);
177
178 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
179 netdev_features_t features);
180
udp_gro_udphdr(struct sk_buff * skb)181 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
182 {
183 struct udphdr *uh;
184 unsigned int hlen, off;
185
186 off = skb_gro_offset(skb);
187 hlen = off + sizeof(*uh);
188 uh = skb_gro_header_fast(skb, off);
189 if (skb_gro_header_hard(skb, hlen))
190 uh = skb_gro_header_slow(skb, hlen, off);
191
192 return uh;
193 }
194
195 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
udp_lib_hash(struct sock * sk)196 static inline int udp_lib_hash(struct sock *sk)
197 {
198 BUG();
199 return 0;
200 }
201
202 void udp_lib_unhash(struct sock *sk);
203 void udp_lib_rehash(struct sock *sk, u16 new_hash);
204
udp_lib_close(struct sock * sk,long timeout)205 static inline void udp_lib_close(struct sock *sk, long timeout)
206 {
207 sk_common_release(sk);
208 }
209
210 int udp_lib_get_port(struct sock *sk, unsigned short snum,
211 unsigned int hash2_nulladdr);
212
213 u32 udp_flow_hashrnd(void);
214
udp_flow_src_port(struct net * net,struct sk_buff * skb,int min,int max,bool use_eth)215 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
216 int min, int max, bool use_eth)
217 {
218 u32 hash;
219
220 if (min >= max) {
221 /* Use default range */
222 inet_get_local_port_range(net, &min, &max);
223 }
224
225 hash = skb_get_hash(skb);
226 if (unlikely(!hash)) {
227 if (use_eth) {
228 /* Can't find a normal hash, caller has indicated an
229 * Ethernet packet so use that to compute a hash.
230 */
231 hash = jhash(skb->data, 2 * ETH_ALEN,
232 (__force u32) skb->protocol);
233 } else {
234 /* Can't derive any sort of hash for the packet, set
235 * to some consistent random value.
236 */
237 hash = udp_flow_hashrnd();
238 }
239 }
240
241 /* Since this is being sent on the wire obfuscate hash a bit
242 * to minimize possbility that any useful information to an
243 * attacker is leaked. Only upper 16 bits are relevant in the
244 * computation for 16 bit port value.
245 */
246 hash ^= hash << 16;
247
248 return htons((((u64) hash * (max - min)) >> 32) + min);
249 }
250
udp_rqueue_get(struct sock * sk)251 static inline int udp_rqueue_get(struct sock *sk)
252 {
253 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
254 }
255
256 /* net/ipv4/udp.c */
257 void udp_destruct_common(struct sock *sk);
258 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
259 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
260 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
261 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
262 int noblock, int *peeked, int *off, int *err);
skb_recv_udp(struct sock * sk,unsigned int flags,int noblock,int * err)263 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
264 int noblock, int *err)
265 {
266 int peeked, off = 0;
267
268 return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err);
269 }
270
271 int udp_v4_early_demux(struct sk_buff *skb);
272 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
273 int udp_get_port(struct sock *sk, unsigned short snum,
274 int (*saddr_cmp)(const struct sock *,
275 const struct sock *));
276 void udp_err(struct sk_buff *, u32);
277 int udp_abort(struct sock *sk, int err);
278 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
279 int udp_push_pending_frames(struct sock *sk);
280 void udp_flush_pending_frames(struct sock *sk);
281 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
282 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
283 int udp_rcv(struct sk_buff *skb);
284 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
285 int udp_init_sock(struct sock *sk);
286 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
287 int __udp_disconnect(struct sock *sk, int flags);
288 int udp_disconnect(struct sock *sk, int flags);
289 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
290 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
291 netdev_features_t features,
292 bool is_ipv6);
293 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
294 char __user *optval, int __user *optlen);
295 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
296 char __user *optval, unsigned int optlen,
297 int (*push_pending_frames)(struct sock *));
298 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
299 __be32 daddr, __be16 dport, int dif);
300 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
301 __be32 daddr, __be16 dport, int dif, int sdif,
302 struct udp_table *tbl, struct sk_buff *skb);
303 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
304 __be16 sport, __be16 dport);
305 struct sock *udp6_lib_lookup(struct net *net,
306 const struct in6_addr *saddr, __be16 sport,
307 const struct in6_addr *daddr, __be16 dport,
308 int dif);
309 struct sock *__udp6_lib_lookup(struct net *net,
310 const struct in6_addr *saddr, __be16 sport,
311 const struct in6_addr *daddr, __be16 dport,
312 int dif, int sdif, struct udp_table *tbl,
313 struct sk_buff *skb);
314 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
315 __be16 sport, __be16 dport);
316
317 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
318 * possibly multiple cache miss on dequeue()
319 */
320 struct udp_dev_scratch {
321 /* skb->truesize and the stateless bit are embedded in a single field;
322 * do not use a bitfield since the compiler emits better/smaller code
323 * this way
324 */
325 u32 _tsize_state;
326
327 #if BITS_PER_LONG == 64
328 /* len and the bit needed to compute skb_csum_unnecessary
329 * will be on cold cache lines at recvmsg time.
330 * skb->len can be stored on 16 bits since the udp header has been
331 * already validated and pulled.
332 */
333 u16 len;
334 bool is_linear;
335 bool csum_unnecessary;
336 #endif
337 };
338
udp_skb_scratch(struct sk_buff * skb)339 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
340 {
341 return (struct udp_dev_scratch *)&skb->dev_scratch;
342 }
343
344 #if BITS_PER_LONG == 64
udp_skb_len(struct sk_buff * skb)345 static inline unsigned int udp_skb_len(struct sk_buff *skb)
346 {
347 return udp_skb_scratch(skb)->len;
348 }
349
udp_skb_csum_unnecessary(struct sk_buff * skb)350 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
351 {
352 return udp_skb_scratch(skb)->csum_unnecessary;
353 }
354
udp_skb_is_linear(struct sk_buff * skb)355 static inline bool udp_skb_is_linear(struct sk_buff *skb)
356 {
357 return udp_skb_scratch(skb)->is_linear;
358 }
359
360 #else
udp_skb_len(struct sk_buff * skb)361 static inline unsigned int udp_skb_len(struct sk_buff *skb)
362 {
363 return skb->len;
364 }
365
udp_skb_csum_unnecessary(struct sk_buff * skb)366 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
367 {
368 return skb_csum_unnecessary(skb);
369 }
370
udp_skb_is_linear(struct sk_buff * skb)371 static inline bool udp_skb_is_linear(struct sk_buff *skb)
372 {
373 return !skb_is_nonlinear(skb);
374 }
375 #endif
376
copy_linear_skb(struct sk_buff * skb,int len,int off,struct iov_iter * to)377 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
378 struct iov_iter *to)
379 {
380 int n;
381
382 n = copy_to_iter(skb->data + off, len, to);
383 if (n == len)
384 return 0;
385
386 iov_iter_revert(to, n);
387 return -EFAULT;
388 }
389
390 /*
391 * SNMP statistics for UDP and UDP-Lite
392 */
393 #define UDP_INC_STATS(net, field, is_udplite) do { \
394 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
395 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
396 #define __UDP_INC_STATS(net, field, is_udplite) do { \
397 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
398 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
399
400 #define __UDP6_INC_STATS(net, field, is_udplite) do { \
401 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
402 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
403 } while(0)
404 #define UDP6_INC_STATS(net, field, __lite) do { \
405 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
406 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
407 } while(0)
408
409 #if IS_ENABLED(CONFIG_IPV6)
410 #define __UDPX_INC_STATS(sk, field) \
411 do { \
412 if ((sk)->sk_family == AF_INET) \
413 __UDP_INC_STATS(sock_net(sk), field, 0); \
414 else \
415 __UDP6_INC_STATS(sock_net(sk), field, 0); \
416 } while (0)
417 #else
418 #define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0)
419 #endif
420
421 #ifdef CONFIG_PROC_FS
422 struct udp_seq_afinfo {
423 sa_family_t family;
424 struct udp_table *udp_table;
425 };
426
427 struct udp_iter_state {
428 struct seq_net_private p;
429 int bucket;
430 };
431
432 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
433 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
434 void udp_seq_stop(struct seq_file *seq, void *v);
435
436 extern const struct seq_operations udp_seq_ops;
437 extern const struct seq_operations udp6_seq_ops;
438
439 int udp4_proc_init(void);
440 void udp4_proc_exit(void);
441 #endif /* CONFIG_PROC_FS */
442
443 int udpv4_offload_init(void);
444
445 void udp_init(void);
446
447 void udp_encap_enable(void);
448 #if IS_ENABLED(CONFIG_IPV6)
449 void udpv6_encap_enable(void);
450 #endif
451
452 #endif /* _UDP_H */
453