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 DECLARE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
99
100 /* sysctl variables for udp */
101 extern long sysctl_udp_mem[3];
102 extern int sysctl_udp_rmem_min;
103 extern int sysctl_udp_wmem_min;
104
105 struct sk_buff;
106
107 /*
108 * Generic checksumming routines for UDP(-Lite) v4 and v6
109 */
__udp_lib_checksum_complete(struct sk_buff * skb)110 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
111 {
112 return (UDP_SKB_CB(skb)->cscov == skb->len ?
113 __skb_checksum_complete(skb) :
114 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
115 }
116
udp_lib_checksum_complete(struct sk_buff * skb)117 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
118 {
119 return !skb_csum_unnecessary(skb) &&
120 __udp_lib_checksum_complete(skb);
121 }
122
123 /**
124 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
125 * @sk: socket we are writing to
126 * @skb: sk_buff containing the filled-in UDP header
127 * (checksum field must be zeroed out)
128 */
udp_csum_outgoing(struct sock * sk,struct sk_buff * skb)129 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
130 {
131 __wsum csum = csum_partial(skb_transport_header(skb),
132 sizeof(struct udphdr), 0);
133 skb_queue_walk(&sk->sk_write_queue, skb) {
134 csum = csum_add(csum, skb->csum);
135 }
136 return csum;
137 }
138
udp_csum(struct sk_buff * skb)139 static inline __wsum udp_csum(struct sk_buff *skb)
140 {
141 __wsum csum = csum_partial(skb_transport_header(skb),
142 sizeof(struct udphdr), skb->csum);
143
144 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
145 csum = csum_add(csum, skb->csum);
146 }
147 return csum;
148 }
149
udp_v4_check(int len,__be32 saddr,__be32 daddr,__wsum base)150 static inline __sum16 udp_v4_check(int len, __be32 saddr,
151 __be32 daddr, __wsum base)
152 {
153 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
154 }
155
156 void udp_set_csum(bool nocheck, struct sk_buff *skb,
157 __be32 saddr, __be32 daddr, int len);
158
udp_csum_pull_header(struct sk_buff * skb)159 static inline void udp_csum_pull_header(struct sk_buff *skb)
160 {
161 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
162 skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
163 skb->csum);
164 skb_pull_rcsum(skb, sizeof(struct udphdr));
165 UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
166 }
167
168 typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
169 __be16 dport);
170
171 void udp_v6_early_demux(struct sk_buff *skb);
172 INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
173
174 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
175 netdev_features_t features, bool is_ipv6);
176
177 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
udp_lib_hash(struct sock * sk)178 static inline int udp_lib_hash(struct sock *sk)
179 {
180 BUG();
181 return 0;
182 }
183
184 void udp_lib_unhash(struct sock *sk);
185 void udp_lib_rehash(struct sock *sk, u16 new_hash);
186
udp_lib_close(struct sock * sk,long timeout)187 static inline void udp_lib_close(struct sock *sk, long timeout)
188 {
189 sk_common_release(sk);
190 }
191
192 int udp_lib_get_port(struct sock *sk, unsigned short snum,
193 unsigned int hash2_nulladdr);
194
195 u32 udp_flow_hashrnd(void);
196
udp_flow_src_port(struct net * net,struct sk_buff * skb,int min,int max,bool use_eth)197 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
198 int min, int max, bool use_eth)
199 {
200 u32 hash;
201
202 if (min >= max) {
203 /* Use default range */
204 inet_get_local_port_range(net, &min, &max);
205 }
206
207 hash = skb_get_hash(skb);
208 if (unlikely(!hash)) {
209 if (use_eth) {
210 /* Can't find a normal hash, caller has indicated an
211 * Ethernet packet so use that to compute a hash.
212 */
213 hash = jhash(skb->data, 2 * ETH_ALEN,
214 (__force u32) skb->protocol);
215 } else {
216 /* Can't derive any sort of hash for the packet, set
217 * to some consistent random value.
218 */
219 hash = udp_flow_hashrnd();
220 }
221 }
222
223 /* Since this is being sent on the wire obfuscate hash a bit
224 * to minimize possbility that any useful information to an
225 * attacker is leaked. Only upper 16 bits are relevant in the
226 * computation for 16 bit port value.
227 */
228 hash ^= hash << 16;
229
230 return htons((((u64) hash * (max - min)) >> 32) + min);
231 }
232
udp_rqueue_get(struct sock * sk)233 static inline int udp_rqueue_get(struct sock *sk)
234 {
235 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
236 }
237
udp_sk_bound_dev_eq(struct net * net,int bound_dev_if,int dif,int sdif)238 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
239 int dif, int sdif)
240 {
241 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
242 return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
243 bound_dev_if, dif, sdif);
244 #else
245 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
246 #endif
247 }
248
249 /* net/ipv4/udp.c */
250 void udp_destruct_common(struct sock *sk);
251 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
252 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
253 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
254 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off,
255 int *err);
skb_recv_udp(struct sock * sk,unsigned int flags,int * err)256 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
257 int *err)
258 {
259 int off = 0;
260
261 return __skb_recv_udp(sk, flags, &off, err);
262 }
263
264 int udp_v4_early_demux(struct sk_buff *skb);
265 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
266 int udp_get_port(struct sock *sk, unsigned short snum,
267 int (*saddr_cmp)(const struct sock *,
268 const struct sock *));
269 int udp_err(struct sk_buff *, u32);
270 int udp_abort(struct sock *sk, int err);
271 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
272 int udp_push_pending_frames(struct sock *sk);
273 void udp_flush_pending_frames(struct sock *sk);
274 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
275 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
276 int udp_rcv(struct sk_buff *skb);
277 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
278 int udp_init_sock(struct sock *sk);
279 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
280 int __udp_disconnect(struct sock *sk, int flags);
281 int udp_disconnect(struct sock *sk, int flags);
282 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
283 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
284 netdev_features_t features,
285 bool is_ipv6);
286 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
287 char __user *optval, int __user *optlen);
288 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
289 sockptr_t optval, unsigned int optlen,
290 int (*push_pending_frames)(struct sock *));
291 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
292 __be32 daddr, __be16 dport, int dif);
293 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
294 __be32 daddr, __be16 dport, int dif, int sdif,
295 struct udp_table *tbl, struct sk_buff *skb);
296 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
297 __be16 sport, __be16 dport);
298 struct sock *udp6_lib_lookup(struct net *net,
299 const struct in6_addr *saddr, __be16 sport,
300 const struct in6_addr *daddr, __be16 dport,
301 int dif);
302 struct sock *__udp6_lib_lookup(struct net *net,
303 const struct in6_addr *saddr, __be16 sport,
304 const struct in6_addr *daddr, __be16 dport,
305 int dif, int sdif, struct udp_table *tbl,
306 struct sk_buff *skb);
307 struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
308 __be16 sport, __be16 dport);
309 int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
310
311 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
312 * possibly multiple cache miss on dequeue()
313 */
314 struct udp_dev_scratch {
315 /* skb->truesize and the stateless bit are embedded in a single field;
316 * do not use a bitfield since the compiler emits better/smaller code
317 * this way
318 */
319 u32 _tsize_state;
320
321 #if BITS_PER_LONG == 64
322 /* len and the bit needed to compute skb_csum_unnecessary
323 * will be on cold cache lines at recvmsg time.
324 * skb->len can be stored on 16 bits since the udp header has been
325 * already validated and pulled.
326 */
327 u16 len;
328 bool is_linear;
329 bool csum_unnecessary;
330 #endif
331 };
332
udp_skb_scratch(struct sk_buff * skb)333 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
334 {
335 return (struct udp_dev_scratch *)&skb->dev_scratch;
336 }
337
338 #if BITS_PER_LONG == 64
udp_skb_len(struct sk_buff * skb)339 static inline unsigned int udp_skb_len(struct sk_buff *skb)
340 {
341 return udp_skb_scratch(skb)->len;
342 }
343
udp_skb_csum_unnecessary(struct sk_buff * skb)344 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
345 {
346 return udp_skb_scratch(skb)->csum_unnecessary;
347 }
348
udp_skb_is_linear(struct sk_buff * skb)349 static inline bool udp_skb_is_linear(struct sk_buff *skb)
350 {
351 return udp_skb_scratch(skb)->is_linear;
352 }
353
354 #else
udp_skb_len(struct sk_buff * skb)355 static inline unsigned int udp_skb_len(struct sk_buff *skb)
356 {
357 return skb->len;
358 }
359
udp_skb_csum_unnecessary(struct sk_buff * skb)360 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
361 {
362 return skb_csum_unnecessary(skb);
363 }
364
udp_skb_is_linear(struct sk_buff * skb)365 static inline bool udp_skb_is_linear(struct sk_buff *skb)
366 {
367 return !skb_is_nonlinear(skb);
368 }
369 #endif
370
copy_linear_skb(struct sk_buff * skb,int len,int off,struct iov_iter * to)371 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
372 struct iov_iter *to)
373 {
374 int n;
375
376 n = copy_to_iter(skb->data + off, len, to);
377 if (n == len)
378 return 0;
379
380 iov_iter_revert(to, n);
381 return -EFAULT;
382 }
383
384 /*
385 * SNMP statistics for UDP and UDP-Lite
386 */
387 #define UDP_INC_STATS(net, field, is_udplite) do { \
388 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
389 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
390 #define __UDP_INC_STATS(net, field, is_udplite) do { \
391 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
392 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
393
394 #define __UDP6_INC_STATS(net, field, is_udplite) do { \
395 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
396 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
397 } while(0)
398 #define UDP6_INC_STATS(net, field, __lite) do { \
399 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
400 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
401 } while(0)
402
403 #if IS_ENABLED(CONFIG_IPV6)
404 #define __UDPX_MIB(sk, ipv4) \
405 ({ \
406 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
407 sock_net(sk)->mib.udp_statistics) : \
408 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
409 sock_net(sk)->mib.udp_stats_in6); \
410 })
411 #else
412 #define __UDPX_MIB(sk, ipv4) \
413 ({ \
414 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
415 sock_net(sk)->mib.udp_statistics; \
416 })
417 #endif
418
419 #define __UDPX_INC_STATS(sk, field) \
420 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
421
422 #ifdef CONFIG_PROC_FS
423 struct udp_seq_afinfo {
424 sa_family_t family;
425 struct udp_table *udp_table;
426 };
427
428 struct udp_iter_state {
429 struct seq_net_private p;
430 int bucket;
431 struct udp_seq_afinfo *bpf_seq_afinfo;
432 };
433
434 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
435 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
436 void udp_seq_stop(struct seq_file *seq, void *v);
437
438 extern const struct seq_operations udp_seq_ops;
439 extern const struct seq_operations udp6_seq_ops;
440
441 int udp4_proc_init(void);
442 void udp4_proc_exit(void);
443 #endif /* CONFIG_PROC_FS */
444
445 int udpv4_offload_init(void);
446
447 void udp_init(void);
448
449 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
450 void udp_encap_enable(void);
451 void udp_encap_disable(void);
452 #if IS_ENABLED(CONFIG_IPV6)
453 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
454 void udpv6_encap_enable(void);
455 #endif
456
udp_rcv_segment(struct sock * sk,struct sk_buff * skb,bool ipv4)457 static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
458 struct sk_buff *skb, bool ipv4)
459 {
460 netdev_features_t features = NETIF_F_SG;
461 struct sk_buff *segs;
462
463 /* Avoid csum recalculation by skb_segment unless userspace explicitly
464 * asks for the final checksum values
465 */
466 if (!inet_get_convert_csum(sk))
467 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
468
469 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
470 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
471 * packets in udp_gro_complete_segment. As does UDP GSO, verified by
472 * udp_send_skb. But when those packets are looped in dev_loopback_xmit
473 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
474 * Reset in this specific case, where PARTIAL is both correct and
475 * required.
476 */
477 if (skb->pkt_type == PACKET_LOOPBACK)
478 skb->ip_summed = CHECKSUM_PARTIAL;
479
480 /* the GSO CB lays after the UDP one, no need to save and restore any
481 * CB fragment
482 */
483 segs = __skb_gso_segment(skb, features, false);
484 if (IS_ERR_OR_NULL(segs)) {
485 int segs_nr = skb_shinfo(skb)->gso_segs;
486
487 atomic_add(segs_nr, &sk->sk_drops);
488 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
489 kfree_skb(skb);
490 return NULL;
491 }
492
493 consume_skb(skb);
494 return segs;
495 }
496
udp_post_segment_fix_csum(struct sk_buff * skb)497 static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
498 {
499 /* UDP-lite can't land here - no GRO */
500 WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov);
501
502 /* UDP packets generated with UDP_SEGMENT and traversing:
503 *
504 * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
505 *
506 * can reach an UDP socket with CHECKSUM_NONE, because
507 * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
508 * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
509 * have a valid checksum, as the GRO engine validates the UDP csum
510 * before the aggregation and nobody strips such info in between.
511 * Instead of adding another check in the tunnel fastpath, we can force
512 * a valid csum after the segmentation.
513 * Additionally fixup the UDP CB.
514 */
515 UDP_SKB_CB(skb)->cscov = skb->len;
516 if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
517 skb->csum_valid = 1;
518 }
519
520 #ifdef CONFIG_BPF_SYSCALL
521 struct sk_psock;
522 struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
523 int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
524 #endif
525
526 #endif /* _UDP_H */
527