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 #include <linux/indirect_call_wrapper.h>
31
32 /**
33 * struct udp_skb_cb - UDP(-Lite) private variables
34 *
35 * @header: private variables used by IPv4/IPv6
36 * @cscov: checksum coverage length (UDP-Lite only)
37 * @partial_cov: if set indicates partial csum coverage
38 */
39 struct udp_skb_cb {
40 union {
41 struct inet_skb_parm h4;
42 #if IS_ENABLED(CONFIG_IPV6)
43 struct inet6_skb_parm h6;
44 #endif
45 } header;
46 __u16 cscov;
47 __u8 partial_cov;
48 };
49 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))
50
51 /**
52 * struct udp_hslot - UDP hash slot
53 *
54 * @head: head of list of sockets
55 * @count: number of sockets in 'head' list
56 * @lock: spinlock protecting changes to head/count
57 */
58 struct udp_hslot {
59 struct hlist_head head;
60 int count;
61 spinlock_t lock;
62 } __attribute__((aligned(2 * sizeof(long))));
63
64 /**
65 * struct udp_table - UDP table
66 *
67 * @hash: hash table, sockets are hashed on (local port)
68 * @hash2: hash table, sockets are hashed on (local port, local address)
69 * @mask: number of slots in hash tables, minus 1
70 * @log: log2(number of slots in hash table)
71 */
72 struct udp_table {
73 struct udp_hslot *hash;
74 struct udp_hslot *hash2;
75 unsigned int mask;
76 unsigned int log;
77 };
78 extern struct udp_table udp_table;
79 void udp_table_init(struct udp_table *, const char *);
udp_hashslot(struct udp_table * table,struct net * net,unsigned int num)80 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
81 struct net *net, unsigned int num)
82 {
83 return &table->hash[udp_hashfn(net, num, table->mask)];
84 }
85 /*
86 * For secondary hash, net_hash_mix() is performed before calling
87 * udp_hashslot2(), this explains difference with udp_hashslot()
88 */
udp_hashslot2(struct udp_table * table,unsigned int hash)89 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
90 unsigned int hash)
91 {
92 return &table->hash2[hash & table->mask];
93 }
94
95 extern struct proto udp_prot;
96
97 extern atomic_long_t udp_memory_allocated;
98
99 /* sysctl variables for udp */
100 extern long sysctl_udp_mem[3];
101 extern int sysctl_udp_rmem_min;
102 extern int sysctl_udp_wmem_min;
103
104 struct sk_buff;
105
106 /*
107 * Generic checksumming routines for UDP(-Lite) v4 and v6
108 */
__udp_lib_checksum_complete(struct sk_buff * skb)109 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
110 {
111 return (UDP_SKB_CB(skb)->cscov == skb->len ?
112 __skb_checksum_complete(skb) :
113 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
114 }
115
udp_lib_checksum_complete(struct sk_buff * skb)116 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
117 {
118 return !skb_csum_unnecessary(skb) &&
119 __udp_lib_checksum_complete(skb);
120 }
121
122 /**
123 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
124 * @sk: socket we are writing to
125 * @skb: sk_buff containing the filled-in UDP header
126 * (checksum field must be zeroed out)
127 */
udp_csum_outgoing(struct sock * sk,struct sk_buff * skb)128 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
129 {
130 __wsum csum = csum_partial(skb_transport_header(skb),
131 sizeof(struct udphdr), 0);
132 skb_queue_walk(&sk->sk_write_queue, skb) {
133 csum = csum_add(csum, skb->csum);
134 }
135 return csum;
136 }
137
udp_csum(struct sk_buff * skb)138 static inline __wsum udp_csum(struct sk_buff *skb)
139 {
140 __wsum csum = csum_partial(skb_transport_header(skb),
141 sizeof(struct udphdr), skb->csum);
142
143 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
144 csum = csum_add(csum, skb->csum);
145 }
146 return csum;
147 }
148
udp_v4_check(int len,__be32 saddr,__be32 daddr,__wsum base)149 static inline __sum16 udp_v4_check(int len, __be32 saddr,
150 __be32 daddr, __wsum base)
151 {
152 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
153 }
154
155 void udp_set_csum(bool nocheck, struct sk_buff *skb,
156 __be32 saddr, __be32 daddr, int len);
157
udp_csum_pull_header(struct sk_buff * skb)158 static inline void udp_csum_pull_header(struct sk_buff *skb)
159 {
160 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
161 skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
162 skb->csum);
163 skb_pull_rcsum(skb, sizeof(struct udphdr));
164 UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
165 }
166
167 typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
168 __be16 dport);
169
170 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_head *,
171 struct sk_buff *));
172 INDIRECT_CALLABLE_DECLARE(int udp4_gro_complete(struct sk_buff *, int));
173 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *,
174 struct sk_buff *));
175 INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int));
176 struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
177 struct udphdr *uh, struct sock *sk);
178 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
179 void udp_v6_early_demux(struct sk_buff *skb);
180
181 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
182 netdev_features_t features, bool is_ipv6);
183
udp_gro_udphdr(struct sk_buff * skb)184 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
185 {
186 struct udphdr *uh;
187 unsigned int hlen, off;
188
189 off = skb_gro_offset(skb);
190 hlen = off + sizeof(*uh);
191 uh = skb_gro_header_fast(skb, off);
192 if (skb_gro_header_hard(skb, hlen))
193 uh = skb_gro_header_slow(skb, hlen, off);
194
195 return uh;
196 }
197
198 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
udp_lib_hash(struct sock * sk)199 static inline int udp_lib_hash(struct sock *sk)
200 {
201 BUG();
202 return 0;
203 }
204
205 void udp_lib_unhash(struct sock *sk);
206 void udp_lib_rehash(struct sock *sk, u16 new_hash);
207
udp_lib_close(struct sock * sk,long timeout)208 static inline void udp_lib_close(struct sock *sk, long timeout)
209 {
210 sk_common_release(sk);
211 }
212
213 int udp_lib_get_port(struct sock *sk, unsigned short snum,
214 unsigned int hash2_nulladdr);
215
216 u32 udp_flow_hashrnd(void);
217
udp_flow_src_port(struct net * net,struct sk_buff * skb,int min,int max,bool use_eth)218 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
219 int min, int max, bool use_eth)
220 {
221 u32 hash;
222
223 if (min >= max) {
224 /* Use default range */
225 inet_get_local_port_range(net, &min, &max);
226 }
227
228 hash = skb_get_hash(skb);
229 if (unlikely(!hash)) {
230 if (use_eth) {
231 /* Can't find a normal hash, caller has indicated an
232 * Ethernet packet so use that to compute a hash.
233 */
234 hash = jhash(skb->data, 2 * ETH_ALEN,
235 (__force u32) skb->protocol);
236 } else {
237 /* Can't derive any sort of hash for the packet, set
238 * to some consistent random value.
239 */
240 hash = udp_flow_hashrnd();
241 }
242 }
243
244 /* Since this is being sent on the wire obfuscate hash a bit
245 * to minimize possbility that any useful information to an
246 * attacker is leaked. Only upper 16 bits are relevant in the
247 * computation for 16 bit port value.
248 */
249 hash ^= hash << 16;
250
251 return htons((((u64) hash * (max - min)) >> 32) + min);
252 }
253
udp_rqueue_get(struct sock * sk)254 static inline int udp_rqueue_get(struct sock *sk)
255 {
256 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
257 }
258
udp_sk_bound_dev_eq(struct net * net,int bound_dev_if,int dif,int sdif)259 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
260 int dif, int sdif)
261 {
262 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
263 return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
264 bound_dev_if, dif, sdif);
265 #else
266 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
267 #endif
268 }
269
270 /* net/ipv4/udp.c */
271 void udp_destruct_sock(struct sock *sk);
272 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
273 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
274 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
275 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
276 int noblock, int *off, int *err);
skb_recv_udp(struct sock * sk,unsigned int flags,int noblock,int * err)277 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
278 int noblock, int *err)
279 {
280 int off = 0;
281
282 return __skb_recv_udp(sk, flags, noblock, &off, err);
283 }
284
285 int udp_v4_early_demux(struct sk_buff *skb);
286 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
287 int udp_get_port(struct sock *sk, unsigned short snum,
288 int (*saddr_cmp)(const struct sock *,
289 const struct sock *));
290 int udp_err(struct sk_buff *, u32);
291 int udp_abort(struct sock *sk, int err);
292 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
293 int udp_push_pending_frames(struct sock *sk);
294 void udp_flush_pending_frames(struct sock *sk);
295 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
296 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
297 int udp_rcv(struct sk_buff *skb);
298 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
299 int udp_init_sock(struct sock *sk);
300 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
301 int __udp_disconnect(struct sock *sk, int flags);
302 int udp_disconnect(struct sock *sk, int flags);
303 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
304 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
305 netdev_features_t features,
306 bool is_ipv6);
307 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
308 char __user *optval, int __user *optlen);
309 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
310 sockptr_t optval, unsigned int optlen,
311 int (*push_pending_frames)(struct sock *));
312 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
313 __be32 daddr, __be16 dport, int dif);
314 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
315 __be32 daddr, __be16 dport, int dif, int sdif,
316 struct udp_table *tbl, struct sk_buff *skb);
317 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
318 __be16 sport, __be16 dport);
319 struct sock *udp6_lib_lookup(struct net *net,
320 const struct in6_addr *saddr, __be16 sport,
321 const struct in6_addr *daddr, __be16 dport,
322 int dif);
323 struct sock *__udp6_lib_lookup(struct net *net,
324 const struct in6_addr *saddr, __be16 sport,
325 const struct in6_addr *daddr, __be16 dport,
326 int dif, int sdif, struct udp_table *tbl,
327 struct sk_buff *skb);
328 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
329 __be16 sport, __be16 dport);
330
331 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
332 * possibly multiple cache miss on dequeue()
333 */
334 struct udp_dev_scratch {
335 /* skb->truesize and the stateless bit are embedded in a single field;
336 * do not use a bitfield since the compiler emits better/smaller code
337 * this way
338 */
339 u32 _tsize_state;
340
341 #if BITS_PER_LONG == 64
342 /* len and the bit needed to compute skb_csum_unnecessary
343 * will be on cold cache lines at recvmsg time.
344 * skb->len can be stored on 16 bits since the udp header has been
345 * already validated and pulled.
346 */
347 u16 len;
348 bool is_linear;
349 bool csum_unnecessary;
350 #endif
351 };
352
udp_skb_scratch(struct sk_buff * skb)353 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
354 {
355 return (struct udp_dev_scratch *)&skb->dev_scratch;
356 }
357
358 #if BITS_PER_LONG == 64
udp_skb_len(struct sk_buff * skb)359 static inline unsigned int udp_skb_len(struct sk_buff *skb)
360 {
361 return udp_skb_scratch(skb)->len;
362 }
363
udp_skb_csum_unnecessary(struct sk_buff * skb)364 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
365 {
366 return udp_skb_scratch(skb)->csum_unnecessary;
367 }
368
udp_skb_is_linear(struct sk_buff * skb)369 static inline bool udp_skb_is_linear(struct sk_buff *skb)
370 {
371 return udp_skb_scratch(skb)->is_linear;
372 }
373
374 #else
udp_skb_len(struct sk_buff * skb)375 static inline unsigned int udp_skb_len(struct sk_buff *skb)
376 {
377 return skb->len;
378 }
379
udp_skb_csum_unnecessary(struct sk_buff * skb)380 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
381 {
382 return skb_csum_unnecessary(skb);
383 }
384
udp_skb_is_linear(struct sk_buff * skb)385 static inline bool udp_skb_is_linear(struct sk_buff *skb)
386 {
387 return !skb_is_nonlinear(skb);
388 }
389 #endif
390
copy_linear_skb(struct sk_buff * skb,int len,int off,struct iov_iter * to)391 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
392 struct iov_iter *to)
393 {
394 int n;
395
396 n = copy_to_iter(skb->data + off, len, to);
397 if (n == len)
398 return 0;
399
400 iov_iter_revert(to, n);
401 return -EFAULT;
402 }
403
404 /*
405 * SNMP statistics for UDP and UDP-Lite
406 */
407 #define UDP_INC_STATS(net, field, is_udplite) do { \
408 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
409 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
410 #define __UDP_INC_STATS(net, field, is_udplite) do { \
411 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
412 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
413
414 #define __UDP6_INC_STATS(net, field, is_udplite) do { \
415 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
416 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
417 } while(0)
418 #define UDP6_INC_STATS(net, field, __lite) do { \
419 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
420 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
421 } while(0)
422
423 #if IS_ENABLED(CONFIG_IPV6)
424 #define __UDPX_MIB(sk, ipv4) \
425 ({ \
426 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
427 sock_net(sk)->mib.udp_statistics) : \
428 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
429 sock_net(sk)->mib.udp_stats_in6); \
430 })
431 #else
432 #define __UDPX_MIB(sk, ipv4) \
433 ({ \
434 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
435 sock_net(sk)->mib.udp_statistics; \
436 })
437 #endif
438
439 #define __UDPX_INC_STATS(sk, field) \
440 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
441
442 #ifdef CONFIG_PROC_FS
443 struct udp_seq_afinfo {
444 sa_family_t family;
445 struct udp_table *udp_table;
446 };
447
448 struct udp_iter_state {
449 struct seq_net_private p;
450 int bucket;
451 struct udp_seq_afinfo *bpf_seq_afinfo;
452 };
453
454 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
455 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
456 void udp_seq_stop(struct seq_file *seq, void *v);
457
458 extern const struct seq_operations udp_seq_ops;
459 extern const struct seq_operations udp6_seq_ops;
460
461 int udp4_proc_init(void);
462 void udp4_proc_exit(void);
463 #endif /* CONFIG_PROC_FS */
464
465 int udpv4_offload_init(void);
466
467 void udp_init(void);
468
469 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
470 void udp_encap_enable(void);
471 void udp_encap_disable(void);
472 #if IS_ENABLED(CONFIG_IPV6)
473 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
474 void udpv6_encap_enable(void);
475 #endif
476
udp_rcv_segment(struct sock * sk,struct sk_buff * skb,bool ipv4)477 static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
478 struct sk_buff *skb, bool ipv4)
479 {
480 netdev_features_t features = NETIF_F_SG;
481 struct sk_buff *segs;
482
483 /* Avoid csum recalculation by skb_segment unless userspace explicitly
484 * asks for the final checksum values
485 */
486 if (!inet_get_convert_csum(sk))
487 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
488
489 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
490 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
491 * packets in udp_gro_complete_segment. As does UDP GSO, verified by
492 * udp_send_skb. But when those packets are looped in dev_loopback_xmit
493 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
494 * Reset in this specific case, where PARTIAL is both correct and
495 * required.
496 */
497 if (skb->pkt_type == PACKET_LOOPBACK)
498 skb->ip_summed = CHECKSUM_PARTIAL;
499
500 /* the GSO CB lays after the UDP one, no need to save and restore any
501 * CB fragment
502 */
503 segs = __skb_gso_segment(skb, features, false);
504 if (IS_ERR_OR_NULL(segs)) {
505 int segs_nr = skb_shinfo(skb)->gso_segs;
506
507 atomic_add(segs_nr, &sk->sk_drops);
508 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
509 kfree_skb(skb);
510 return NULL;
511 }
512
513 consume_skb(skb);
514 return segs;
515 }
516
517 #ifdef CONFIG_BPF_STREAM_PARSER
518 struct sk_psock;
519 struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
520 #endif /* BPF_STREAM_PARSER */
521
522 #endif /* _UDP_H */
523