1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Definitions for the UDP module.
8 *
9 * Version: @(#)udp.h 1.0.2 05/07/93
10 *
11 * Authors: Ross Biro
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 *
14 * Fixes:
15 * Alan Cox : Turned on udp checksums. I don't want to
16 * chase 'memory corruption' bugs that aren't!
17 */
18 #ifndef _UDP_H
19 #define _UDP_H
20
21 #include <linux/list.h>
22 #include <linux/bug.h>
23 #include <net/inet_sock.h>
24 #include <net/sock.h>
25 #include <net/snmp.h>
26 #include <net/ip.h>
27 #include <linux/ipv6.h>
28 #include <linux/seq_file.h>
29 #include <linux/poll.h>
30
31 /**
32 * struct udp_skb_cb - UDP(-Lite) private variables
33 *
34 * @header: private variables used by IPv4/IPv6
35 * @cscov: checksum coverage length (UDP-Lite only)
36 * @partial_cov: if set indicates partial csum coverage
37 */
38 struct udp_skb_cb {
39 union {
40 struct inet_skb_parm h4;
41 #if IS_ENABLED(CONFIG_IPV6)
42 struct inet6_skb_parm h6;
43 #endif
44 } header;
45 __u16 cscov;
46 __u8 partial_cov;
47 };
48 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))
49
50 /**
51 * struct udp_hslot - UDP hash slot
52 *
53 * @head: head of list of sockets
54 * @count: number of sockets in 'head' list
55 * @lock: spinlock protecting changes to head/count
56 */
57 struct udp_hslot {
58 struct hlist_head head;
59 int count;
60 spinlock_t lock;
61 } __attribute__((aligned(2 * sizeof(long))));
62
63 /**
64 * struct udp_table - UDP table
65 *
66 * @hash: hash table, sockets are hashed on (local port)
67 * @hash2: hash table, sockets are hashed on (local port, local address)
68 * @mask: number of slots in hash tables, minus 1
69 * @log: log2(number of slots in hash table)
70 */
71 struct udp_table {
72 struct udp_hslot *hash;
73 struct udp_hslot *hash2;
74 unsigned int mask;
75 unsigned int log;
76 };
77 extern struct udp_table udp_table;
78 void udp_table_init(struct udp_table *, const char *);
udp_hashslot(struct udp_table * table,struct net * net,unsigned int num)79 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
80 struct net *net, unsigned int num)
81 {
82 return &table->hash[udp_hashfn(net, num, table->mask)];
83 }
84 /*
85 * For secondary hash, net_hash_mix() is performed before calling
86 * udp_hashslot2(), this explains difference with udp_hashslot()
87 */
udp_hashslot2(struct udp_table * table,unsigned int hash)88 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
89 unsigned int hash)
90 {
91 return &table->hash2[hash & table->mask];
92 }
93
94 extern struct proto udp_prot;
95
96 extern atomic_long_t udp_memory_allocated;
97
98 /* sysctl variables for udp */
99 extern long sysctl_udp_mem[3];
100 extern int sysctl_udp_rmem_min;
101 extern int sysctl_udp_wmem_min;
102
103 struct sk_buff;
104
105 /*
106 * Generic checksumming routines for UDP(-Lite) v4 and v6
107 */
__udp_lib_checksum_complete(struct sk_buff * skb)108 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
109 {
110 return (UDP_SKB_CB(skb)->cscov == skb->len ?
111 __skb_checksum_complete(skb) :
112 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
113 }
114
udp_lib_checksum_complete(struct sk_buff * skb)115 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
116 {
117 return !skb_csum_unnecessary(skb) &&
118 __udp_lib_checksum_complete(skb);
119 }
120
121 /**
122 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
123 * @sk: socket we are writing to
124 * @skb: sk_buff containing the filled-in UDP header
125 * (checksum field must be zeroed out)
126 */
udp_csum_outgoing(struct sock * sk,struct sk_buff * skb)127 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
128 {
129 __wsum csum = csum_partial(skb_transport_header(skb),
130 sizeof(struct udphdr), 0);
131 skb_queue_walk(&sk->sk_write_queue, skb) {
132 csum = csum_add(csum, skb->csum);
133 }
134 return csum;
135 }
136
udp_csum(struct sk_buff * skb)137 static inline __wsum udp_csum(struct sk_buff *skb)
138 {
139 __wsum csum = csum_partial(skb_transport_header(skb),
140 sizeof(struct udphdr), skb->csum);
141
142 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
143 csum = csum_add(csum, skb->csum);
144 }
145 return csum;
146 }
147
udp_v4_check(int len,__be32 saddr,__be32 daddr,__wsum base)148 static inline __sum16 udp_v4_check(int len, __be32 saddr,
149 __be32 daddr, __wsum base)
150 {
151 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
152 }
153
154 void udp_set_csum(bool nocheck, struct sk_buff *skb,
155 __be32 saddr, __be32 daddr, int len);
156
udp_csum_pull_header(struct sk_buff * skb)157 static inline void udp_csum_pull_header(struct sk_buff *skb)
158 {
159 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
160 skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
161 skb->csum);
162 skb_pull_rcsum(skb, sizeof(struct udphdr));
163 UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
164 }
165
166 typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
167 __be16 dport);
168
169 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
170 struct udphdr *uh, udp_lookup_t lookup);
171 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
172
173 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
174 netdev_features_t features);
175
udp_gro_udphdr(struct sk_buff * skb)176 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
177 {
178 struct udphdr *uh;
179 unsigned int hlen, off;
180
181 off = skb_gro_offset(skb);
182 hlen = off + sizeof(*uh);
183 uh = skb_gro_header_fast(skb, off);
184 if (skb_gro_header_hard(skb, hlen))
185 uh = skb_gro_header_slow(skb, hlen, off);
186
187 return uh;
188 }
189
190 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
udp_lib_hash(struct sock * sk)191 static inline int udp_lib_hash(struct sock *sk)
192 {
193 BUG();
194 return 0;
195 }
196
197 void udp_lib_unhash(struct sock *sk);
198 void udp_lib_rehash(struct sock *sk, u16 new_hash);
199
udp_lib_close(struct sock * sk,long timeout)200 static inline void udp_lib_close(struct sock *sk, long timeout)
201 {
202 sk_common_release(sk);
203 }
204
205 int udp_lib_get_port(struct sock *sk, unsigned short snum,
206 unsigned int hash2_nulladdr);
207
208 u32 udp_flow_hashrnd(void);
209
udp_flow_src_port(struct net * net,struct sk_buff * skb,int min,int max,bool use_eth)210 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
211 int min, int max, bool use_eth)
212 {
213 u32 hash;
214
215 if (min >= max) {
216 /* Use default range */
217 inet_get_local_port_range(net, &min, &max);
218 }
219
220 hash = skb_get_hash(skb);
221 if (unlikely(!hash)) {
222 if (use_eth) {
223 /* Can't find a normal hash, caller has indicated an
224 * Ethernet packet so use that to compute a hash.
225 */
226 hash = jhash(skb->data, 2 * ETH_ALEN,
227 (__force u32) skb->protocol);
228 } else {
229 /* Can't derive any sort of hash for the packet, set
230 * to some consistent random value.
231 */
232 hash = udp_flow_hashrnd();
233 }
234 }
235
236 /* Since this is being sent on the wire obfuscate hash a bit
237 * to minimize possbility that any useful information to an
238 * attacker is leaked. Only upper 16 bits are relevant in the
239 * computation for 16 bit port value.
240 */
241 hash ^= hash << 16;
242
243 return htons((((u64) hash * (max - min)) >> 32) + min);
244 }
245
udp_rqueue_get(struct sock * sk)246 static inline int udp_rqueue_get(struct sock *sk)
247 {
248 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
249 }
250
udp_sk_bound_dev_eq(struct net * net,int bound_dev_if,int dif,int sdif)251 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
252 int dif, int sdif)
253 {
254 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
255 return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept,
256 bound_dev_if, dif, sdif);
257 #else
258 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
259 #endif
260 }
261
262 /* net/ipv4/udp.c */
263 void udp_destruct_sock(struct sock *sk);
264 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
265 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
266 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
267 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
268 int noblock, int *off, int *err);
skb_recv_udp(struct sock * sk,unsigned int flags,int noblock,int * err)269 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
270 int noblock, int *err)
271 {
272 int off = 0;
273
274 return __skb_recv_udp(sk, flags, noblock, &off, err);
275 }
276
277 int udp_v4_early_demux(struct sk_buff *skb);
278 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
279 int udp_get_port(struct sock *sk, unsigned short snum,
280 int (*saddr_cmp)(const struct sock *,
281 const struct sock *));
282 int udp_err(struct sk_buff *, u32);
283 int udp_abort(struct sock *sk, int err);
284 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
285 int udp_push_pending_frames(struct sock *sk);
286 void udp_flush_pending_frames(struct sock *sk);
287 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
288 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
289 int udp_rcv(struct sk_buff *skb);
290 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
291 int udp_init_sock(struct sock *sk);
292 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
293 int __udp_disconnect(struct sock *sk, int flags);
294 int udp_disconnect(struct sock *sk, int flags);
295 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
296 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
297 netdev_features_t features,
298 bool is_ipv6);
299 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
300 char __user *optval, int __user *optlen);
301 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
302 char __user *optval, unsigned int optlen,
303 int (*push_pending_frames)(struct sock *));
304 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
305 __be32 daddr, __be16 dport, int dif);
306 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
307 __be32 daddr, __be16 dport, int dif, int sdif,
308 struct udp_table *tbl, struct sk_buff *skb);
309 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
310 __be16 sport, __be16 dport);
311 struct sock *udp6_lib_lookup(struct net *net,
312 const struct in6_addr *saddr, __be16 sport,
313 const struct in6_addr *daddr, __be16 dport,
314 int dif);
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, int sdif, struct udp_table *tbl,
319 struct sk_buff *skb);
320 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
321 __be16 sport, __be16 dport);
322
323 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
324 * possibly multiple cache miss on dequeue()
325 */
326 struct udp_dev_scratch {
327 /* skb->truesize and the stateless bit are embedded in a single field;
328 * do not use a bitfield since the compiler emits better/smaller code
329 * this way
330 */
331 u32 _tsize_state;
332
333 #if BITS_PER_LONG == 64
334 /* len and the bit needed to compute skb_csum_unnecessary
335 * will be on cold cache lines at recvmsg time.
336 * skb->len can be stored on 16 bits since the udp header has been
337 * already validated and pulled.
338 */
339 u16 len;
340 bool is_linear;
341 bool csum_unnecessary;
342 #endif
343 };
344
udp_skb_scratch(struct sk_buff * skb)345 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
346 {
347 return (struct udp_dev_scratch *)&skb->dev_scratch;
348 }
349
350 #if BITS_PER_LONG == 64
udp_skb_len(struct sk_buff * skb)351 static inline unsigned int udp_skb_len(struct sk_buff *skb)
352 {
353 return udp_skb_scratch(skb)->len;
354 }
355
udp_skb_csum_unnecessary(struct sk_buff * skb)356 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
357 {
358 return udp_skb_scratch(skb)->csum_unnecessary;
359 }
360
udp_skb_is_linear(struct sk_buff * skb)361 static inline bool udp_skb_is_linear(struct sk_buff *skb)
362 {
363 return udp_skb_scratch(skb)->is_linear;
364 }
365
366 #else
udp_skb_len(struct sk_buff * skb)367 static inline unsigned int udp_skb_len(struct sk_buff *skb)
368 {
369 return skb->len;
370 }
371
udp_skb_csum_unnecessary(struct sk_buff * skb)372 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
373 {
374 return skb_csum_unnecessary(skb);
375 }
376
udp_skb_is_linear(struct sk_buff * skb)377 static inline bool udp_skb_is_linear(struct sk_buff *skb)
378 {
379 return !skb_is_nonlinear(skb);
380 }
381 #endif
382
copy_linear_skb(struct sk_buff * skb,int len,int off,struct iov_iter * to)383 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
384 struct iov_iter *to)
385 {
386 int n;
387
388 n = copy_to_iter(skb->data + off, len, to);
389 if (n == len)
390 return 0;
391
392 iov_iter_revert(to, n);
393 return -EFAULT;
394 }
395
396 /*
397 * SNMP statistics for UDP and UDP-Lite
398 */
399 #define UDP_INC_STATS(net, field, is_udplite) do { \
400 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
401 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
402 #define __UDP_INC_STATS(net, field, is_udplite) do { \
403 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
404 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
405
406 #define __UDP6_INC_STATS(net, field, is_udplite) do { \
407 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
408 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
409 } while(0)
410 #define UDP6_INC_STATS(net, field, __lite) do { \
411 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
412 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
413 } while(0)
414
415 #if IS_ENABLED(CONFIG_IPV6)
416 #define __UDPX_MIB(sk, ipv4) \
417 ({ \
418 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
419 sock_net(sk)->mib.udp_statistics) : \
420 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
421 sock_net(sk)->mib.udp_stats_in6); \
422 })
423 #else
424 #define __UDPX_MIB(sk, ipv4) \
425 ({ \
426 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
427 sock_net(sk)->mib.udp_statistics; \
428 })
429 #endif
430
431 #define __UDPX_INC_STATS(sk, field) \
432 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
433
434 #ifdef CONFIG_PROC_FS
435 struct udp_seq_afinfo {
436 sa_family_t family;
437 struct udp_table *udp_table;
438 };
439
440 struct udp_iter_state {
441 struct seq_net_private p;
442 int bucket;
443 };
444
445 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
446 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
447 void udp_seq_stop(struct seq_file *seq, void *v);
448
449 extern const struct seq_operations udp_seq_ops;
450 extern const struct seq_operations udp6_seq_ops;
451
452 int udp4_proc_init(void);
453 void udp4_proc_exit(void);
454 #endif /* CONFIG_PROC_FS */
455
456 int udpv4_offload_init(void);
457
458 void udp_init(void);
459
460 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
461 void udp_encap_enable(void);
462 #if IS_ENABLED(CONFIG_IPV6)
463 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
464 void udpv6_encap_enable(void);
465 #endif
466
udp_rcv_segment(struct sock * sk,struct sk_buff * skb,bool ipv4)467 static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
468 struct sk_buff *skb, bool ipv4)
469 {
470 netdev_features_t features = NETIF_F_SG;
471 struct sk_buff *segs;
472
473 /* Avoid csum recalculation by skb_segment unless userspace explicitly
474 * asks for the final checksum values
475 */
476 if (!inet_get_convert_csum(sk))
477 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
478
479 /* the GSO CB lays after the UDP one, no need to save and restore any
480 * CB fragment
481 */
482 segs = __skb_gso_segment(skb, features, false);
483 if (IS_ERR_OR_NULL(segs)) {
484 int segs_nr = skb_shinfo(skb)->gso_segs;
485
486 atomic_add(segs_nr, &sk->sk_drops);
487 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
488 kfree_skb(skb);
489 return NULL;
490 }
491
492 consume_skb(skb);
493 return segs;
494 }
495
496 #endif /* _UDP_H */
497
