Line data Source code
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 *);
80 82 : static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
81 : struct net *net, unsigned int num)
82 : {
83 82 : 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 : */
89 80 : static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
90 : unsigned int hash)
91 : {
92 80 : 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 : */
109 0 : static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
110 : {
111 0 : return (UDP_SKB_CB(skb)->cscov == skb->len ?
112 0 : __skb_checksum_complete(skb) :
113 0 : __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
114 : }
115 :
116 2 : static inline int udp_lib_checksum_complete(struct sk_buff *skb)
117 : {
118 2 : return !skb_csum_unnecessary(skb) &&
119 0 : __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 : */
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 :
138 14 : static inline __wsum udp_csum(struct sk_buff *skb)
139 : {
140 14 : __wsum csum = csum_partial(skb_transport_header(skb),
141 : sizeof(struct udphdr), skb->csum);
142 :
143 14 : for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
144 0 : csum = csum_add(csum, skb->csum);
145 : }
146 14 : return csum;
147 : }
148 :
149 0 : static inline __sum16 udp_v4_check(int len, __be32 saddr,
150 : __be32 daddr, __wsum base)
151 : {
152 0 : 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 :
158 2 : static inline void udp_csum_pull_header(struct sk_buff *skb)
159 : {
160 2 : if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
161 0 : skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
162 : skb->csum);
163 2 : skb_pull_rcsum(skb, sizeof(struct udphdr));
164 2 : UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
165 2 : }
166 :
167 : typedef struct sock *(*udp_lookup_t)(const 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 : INDIRECT_CALLABLE_DECLARE(void udp_v6_early_demux(struct sk_buff *));
177 : INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
178 :
179 : struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
180 : struct udphdr *uh, struct sock *sk);
181 : int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
182 :
183 : struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
184 : netdev_features_t features, bool is_ipv6);
185 :
186 2 : static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
187 : {
188 2 : struct udphdr *uh;
189 2 : unsigned int hlen, off;
190 :
191 2 : off = skb_gro_offset(skb);
192 2 : hlen = off + sizeof(*uh);
193 2 : uh = skb_gro_header_fast(skb, off);
194 2 : if (skb_gro_header_hard(skb, hlen))
195 2 : uh = skb_gro_header_slow(skb, hlen, off);
196 :
197 2 : return uh;
198 : }
199 :
200 : /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
201 0 : static inline int udp_lib_hash(struct sock *sk)
202 : {
203 0 : BUG();
204 : return 0;
205 : }
206 :
207 : void udp_lib_unhash(struct sock *sk);
208 : void udp_lib_rehash(struct sock *sk, u16 new_hash);
209 :
210 39 : static inline void udp_lib_close(struct sock *sk, long timeout)
211 : {
212 39 : sk_common_release(sk);
213 39 : }
214 :
215 : int udp_lib_get_port(struct sock *sk, unsigned short snum,
216 : unsigned int hash2_nulladdr);
217 :
218 : u32 udp_flow_hashrnd(void);
219 :
220 : static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
221 : int min, int max, bool use_eth)
222 : {
223 : u32 hash;
224 :
225 : if (min >= max) {
226 : /* Use default range */
227 : inet_get_local_port_range(net, &min, &max);
228 : }
229 :
230 : hash = skb_get_hash(skb);
231 : if (unlikely(!hash)) {
232 : if (use_eth) {
233 : /* Can't find a normal hash, caller has indicated an
234 : * Ethernet packet so use that to compute a hash.
235 : */
236 : hash = jhash(skb->data, 2 * ETH_ALEN,
237 : (__force u32) skb->protocol);
238 : } else {
239 : /* Can't derive any sort of hash for the packet, set
240 : * to some consistent random value.
241 : */
242 : hash = udp_flow_hashrnd();
243 : }
244 : }
245 :
246 : /* Since this is being sent on the wire obfuscate hash a bit
247 : * to minimize possbility that any useful information to an
248 : * attacker is leaked. Only upper 16 bits are relevant in the
249 : * computation for 16 bit port value.
250 : */
251 : hash ^= hash << 16;
252 :
253 : return htons((((u64) hash * (max - min)) >> 32) + min);
254 : }
255 :
256 0 : static inline int udp_rqueue_get(struct sock *sk)
257 : {
258 0 : return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
259 : }
260 :
261 16 : static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
262 : int dif, int sdif)
263 : {
264 : #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
265 : return inet_bound_dev_eq(!!net->ipv4.sysctl_udp_l3mdev_accept,
266 : bound_dev_if, dif, sdif);
267 : #else
268 16 : return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
269 : #endif
270 : }
271 :
272 : /* net/ipv4/udp.c */
273 : void udp_destruct_sock(struct sock *sk);
274 : void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
275 : int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
276 : void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
277 : struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
278 : int noblock, int *off, int *err);
279 : static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
280 : int noblock, int *err)
281 : {
282 : int off = 0;
283 :
284 : return __skb_recv_udp(sk, flags, noblock, &off, err);
285 : }
286 :
287 : int udp_v4_early_demux(struct sk_buff *skb);
288 : bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
289 : int udp_get_port(struct sock *sk, unsigned short snum,
290 : int (*saddr_cmp)(const struct sock *,
291 : const struct sock *));
292 : int udp_err(struct sk_buff *, u32);
293 : int udp_abort(struct sock *sk, int err);
294 : int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
295 : int udp_push_pending_frames(struct sock *sk);
296 : void udp_flush_pending_frames(struct sock *sk);
297 : int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
298 : void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
299 : int udp_rcv(struct sk_buff *skb);
300 : int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
301 : int udp_init_sock(struct sock *sk);
302 : int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
303 : int __udp_disconnect(struct sock *sk, int flags);
304 : int udp_disconnect(struct sock *sk, int flags);
305 : __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
306 : struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
307 : netdev_features_t features,
308 : bool is_ipv6);
309 : int udp_lib_getsockopt(struct sock *sk, int level, int optname,
310 : char __user *optval, int __user *optlen);
311 : int udp_lib_setsockopt(struct sock *sk, int level, int optname,
312 : sockptr_t optval, unsigned int optlen,
313 : int (*push_pending_frames)(struct sock *));
314 : struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
315 : __be32 daddr, __be16 dport, int dif);
316 : struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
317 : __be32 daddr, __be16 dport, int dif, int sdif,
318 : struct udp_table *tbl, struct sk_buff *skb);
319 : struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
320 : __be16 sport, __be16 dport);
321 : struct sock *udp6_lib_lookup(struct net *net,
322 : const struct in6_addr *saddr, __be16 sport,
323 : const struct in6_addr *daddr, __be16 dport,
324 : int dif);
325 : struct sock *__udp6_lib_lookup(struct net *net,
326 : const struct in6_addr *saddr, __be16 sport,
327 : const struct in6_addr *daddr, __be16 dport,
328 : int dif, int sdif, struct udp_table *tbl,
329 : struct sk_buff *skb);
330 : struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
331 : __be16 sport, __be16 dport);
332 :
333 : /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
334 : * possibly multiple cache miss on dequeue()
335 : */
336 : struct udp_dev_scratch {
337 : /* skb->truesize and the stateless bit are embedded in a single field;
338 : * do not use a bitfield since the compiler emits better/smaller code
339 : * this way
340 : */
341 : u32 _tsize_state;
342 :
343 : #if BITS_PER_LONG == 64
344 : /* len and the bit needed to compute skb_csum_unnecessary
345 : * will be on cold cache lines at recvmsg time.
346 : * skb->len can be stored on 16 bits since the udp header has been
347 : * already validated and pulled.
348 : */
349 : u16 len;
350 : bool is_linear;
351 : bool csum_unnecessary;
352 : #endif
353 : };
354 :
355 14 : static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
356 : {
357 6 : return (struct udp_dev_scratch *)&skb->dev_scratch;
358 : }
359 :
360 : #if BITS_PER_LONG == 64
361 2 : static inline unsigned int udp_skb_len(struct sk_buff *skb)
362 : {
363 2 : return udp_skb_scratch(skb)->len;
364 : }
365 :
366 2 : static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
367 : {
368 2 : return udp_skb_scratch(skb)->csum_unnecessary;
369 : }
370 :
371 2 : static inline bool udp_skb_is_linear(struct sk_buff *skb)
372 : {
373 2 : return udp_skb_scratch(skb)->is_linear;
374 : }
375 :
376 : #else
377 : static inline unsigned int udp_skb_len(struct sk_buff *skb)
378 : {
379 : return skb->len;
380 : }
381 :
382 : static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
383 : {
384 : return skb_csum_unnecessary(skb);
385 : }
386 :
387 : static inline bool udp_skb_is_linear(struct sk_buff *skb)
388 : {
389 : return !skb_is_nonlinear(skb);
390 : }
391 : #endif
392 :
393 0 : static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
394 : struct iov_iter *to)
395 : {
396 0 : int n;
397 :
398 0 : n = copy_to_iter(skb->data + off, len, to);
399 0 : if (n == len)
400 : return 0;
401 :
402 0 : iov_iter_revert(to, n);
403 0 : return -EFAULT;
404 : }
405 :
406 : /*
407 : * SNMP statistics for UDP and UDP-Lite
408 : */
409 : #define UDP_INC_STATS(net, field, is_udplite) do { \
410 : if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
411 : else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
412 : #define __UDP_INC_STATS(net, field, is_udplite) do { \
413 : if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
414 : else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
415 :
416 : #define __UDP6_INC_STATS(net, field, is_udplite) do { \
417 : if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
418 : else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
419 : } while(0)
420 : #define UDP6_INC_STATS(net, field, __lite) do { \
421 : if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
422 : else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
423 : } while(0)
424 :
425 : #if IS_ENABLED(CONFIG_IPV6)
426 : #define __UDPX_MIB(sk, ipv4) \
427 : ({ \
428 : ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
429 : sock_net(sk)->mib.udp_statistics) : \
430 : (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
431 : sock_net(sk)->mib.udp_stats_in6); \
432 : })
433 : #else
434 : #define __UDPX_MIB(sk, ipv4) \
435 : ({ \
436 : IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
437 : sock_net(sk)->mib.udp_statistics; \
438 : })
439 : #endif
440 :
441 : #define __UDPX_INC_STATS(sk, field) \
442 : __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
443 :
444 : #ifdef CONFIG_PROC_FS
445 : struct udp_seq_afinfo {
446 : sa_family_t family;
447 : struct udp_table *udp_table;
448 : };
449 :
450 : struct udp_iter_state {
451 : struct seq_net_private p;
452 : int bucket;
453 : struct udp_seq_afinfo *bpf_seq_afinfo;
454 : };
455 :
456 : void *udp_seq_start(struct seq_file *seq, loff_t *pos);
457 : void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
458 : void udp_seq_stop(struct seq_file *seq, void *v);
459 :
460 : extern const struct seq_operations udp_seq_ops;
461 : extern const struct seq_operations udp6_seq_ops;
462 :
463 : int udp4_proc_init(void);
464 : void udp4_proc_exit(void);
465 : #endif /* CONFIG_PROC_FS */
466 :
467 : int udpv4_offload_init(void);
468 :
469 : void udp_init(void);
470 :
471 : DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
472 : void udp_encap_enable(void);
473 : void udp_encap_disable(void);
474 : #if IS_ENABLED(CONFIG_IPV6)
475 : DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
476 : void udpv6_encap_enable(void);
477 : #endif
478 :
479 0 : static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
480 : struct sk_buff *skb, bool ipv4)
481 : {
482 0 : netdev_features_t features = NETIF_F_SG;
483 0 : struct sk_buff *segs;
484 :
485 : /* Avoid csum recalculation by skb_segment unless userspace explicitly
486 : * asks for the final checksum values
487 : */
488 0 : if (!inet_get_convert_csum(sk))
489 0 : features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
490 :
491 : /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
492 : * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
493 : * packets in udp_gro_complete_segment. As does UDP GSO, verified by
494 : * udp_send_skb. But when those packets are looped in dev_loopback_xmit
495 : * their ip_summed is set to CHECKSUM_UNNECESSARY. Reset in this
496 : * specific case, where PARTIAL is both correct and required.
497 : */
498 0 : if (skb->pkt_type == PACKET_LOOPBACK)
499 0 : skb->ip_summed = CHECKSUM_PARTIAL;
500 :
501 : /* the GSO CB lays after the UDP one, no need to save and restore any
502 : * CB fragment
503 : */
504 0 : segs = __skb_gso_segment(skb, features, false);
505 0 : if (IS_ERR_OR_NULL(segs)) {
506 0 : int segs_nr = skb_shinfo(skb)->gso_segs;
507 :
508 0 : atomic_add(segs_nr, &sk->sk_drops);
509 0 : SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
510 0 : kfree_skb(skb);
511 0 : return NULL;
512 : }
513 :
514 0 : consume_skb(skb);
515 0 : return segs;
516 : }
517 :
518 : #ifdef CONFIG_BPF_STREAM_PARSER
519 : struct sk_psock;
520 : struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
521 : #endif /* BPF_STREAM_PARSER */
522 :
523 : #endif /* _UDP_H */
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