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/gso.h>
25#include <net/sock.h>
26#include <net/snmp.h>
27#include <net/ip.h>
28#include <linux/ipv6.h>
29#include <linux/seq_file.h>
30#include <linux/poll.h>
31#include <linux/indirect_call_wrapper.h>
32
33/**
34 * struct udp_skb_cb - UDP(-Lite) private variables
35 *
36 * @header: private variables used by IPv4/IPv6
37 * @cscov: checksum coverage length (UDP-Lite only)
38 * @partial_cov: if set indicates partial csum coverage
39 */
40struct udp_skb_cb {
41 union {
42 struct inet_skb_parm h4;
43#if IS_ENABLED(CONFIG_IPV6)
44 struct inet6_skb_parm h6;
45#endif
46 } header;
47 __u16 cscov;
48 __u8 partial_cov;
49};
50#define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))
51
52/**
53 * struct udp_hslot - UDP hash slot used by udp_table.hash/hash4
54 *
55 * @head: head of list of sockets
56 * @nulls_head: head of list of sockets, only used by hash4
57 * @count: number of sockets in 'head' list
58 * @lock: spinlock protecting changes to head/count
59 */
60struct udp_hslot {
61 union {
62 struct hlist_head head;
63 /* hash4 uses hlist_nulls to avoid moving wrongly onto another
64 * hlist, because rehash() can happen with lookup().
65 */
66 struct hlist_nulls_head nulls_head;
67 };
68 int count;
69 spinlock_t lock;
70} __aligned(2 * sizeof(long));
71
72/**
73 * struct udp_hslot_main - UDP hash slot used by udp_table.hash2
74 *
75 * @hslot: basic hash slot
76 * @hash4_cnt: number of sockets in hslot4 of the same
77 * (local port, local address)
78 */
79struct udp_hslot_main {
80 struct udp_hslot hslot; /* must be the first member */
81#if !IS_ENABLED(CONFIG_BASE_SMALL)
82 u32 hash4_cnt;
83#endif
84} __aligned(2 * sizeof(long));
85#define UDP_HSLOT_MAIN(__hslot) ((struct udp_hslot_main *)(__hslot))
86
87/**
88 * struct udp_table - UDP table
89 *
90 * @hash: hash table, sockets are hashed on (local port)
91 * @hash2: hash table, sockets are hashed on (local port, local address)
92 * @hash4: hash table, connected sockets are hashed on
93 * (local port, local address, remote port, remote address)
94 * @mask: number of slots in hash tables, minus 1
95 * @log: log2(number of slots in hash table)
96 */
97struct udp_table {
98 struct udp_hslot *hash;
99 struct udp_hslot_main *hash2;
100#if !IS_ENABLED(CONFIG_BASE_SMALL)
101 struct udp_hslot *hash4;
102#endif
103 unsigned int mask;
104 unsigned int log;
105};
106extern struct udp_table udp_table;
107void udp_table_init(struct udp_table *, const char *);
108static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
109 const struct net *net,
110 unsigned int num)
111{
112 return &table->hash[udp_hashfn(net, num, mask: table->mask)];
113}
114
115/*
116 * For secondary hash, net_hash_mix() is performed before calling
117 * udp_hashslot2(), this explains difference with udp_hashslot()
118 */
119static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
120 unsigned int hash)
121{
122 return &table->hash2[hash & table->mask].hslot;
123}
124
125#if IS_ENABLED(CONFIG_BASE_SMALL)
126static inline void udp_table_hash4_init(struct udp_table *table)
127{
128}
129
130static inline struct udp_hslot *udp_hashslot4(struct udp_table *table,
131 unsigned int hash)
132{
133 BUILD_BUG();
134 return NULL;
135}
136
137static inline bool udp_hashed4(const struct sock *sk)
138{
139 return false;
140}
141
142static inline unsigned int udp_hash4_slot_size(void)
143{
144 return 0;
145}
146
147static inline bool udp_has_hash4(const struct udp_hslot *hslot2)
148{
149 return false;
150}
151
152static inline void udp_hash4_inc(struct udp_hslot *hslot2)
153{
154}
155
156static inline void udp_hash4_dec(struct udp_hslot *hslot2)
157{
158}
159#else /* !CONFIG_BASE_SMALL */
160
161/* Must be called with table->hash2 initialized */
162static inline void udp_table_hash4_init(struct udp_table *table)
163{
164 table->hash4 = (void *)(table->hash2 + (table->mask + 1));
165 for (int i = 0; i <= table->mask; i++) {
166 table->hash2[i].hash4_cnt = 0;
167
168 INIT_HLIST_NULLS_HEAD(&table->hash4[i].nulls_head, i);
169 table->hash4[i].count = 0;
170 spin_lock_init(&table->hash4[i].lock);
171 }
172}
173
174static inline struct udp_hslot *udp_hashslot4(struct udp_table *table,
175 unsigned int hash)
176{
177 return &table->hash4[hash & table->mask];
178}
179
180static inline bool udp_hashed4(const struct sock *sk)
181{
182 return !hlist_nulls_unhashed(&udp_sk(sk)->udp_lrpa_node);
183}
184
185static inline unsigned int udp_hash4_slot_size(void)
186{
187 return sizeof(struct udp_hslot);
188}
189
190static inline bool udp_has_hash4(const struct udp_hslot *hslot2)
191{
192 return UDP_HSLOT_MAIN(hslot2)->hash4_cnt;
193}
194
195static inline void udp_hash4_inc(struct udp_hslot *hslot2)
196{
197 UDP_HSLOT_MAIN(hslot2)->hash4_cnt++;
198}
199
200static inline void udp_hash4_dec(struct udp_hslot *hslot2)
201{
202 UDP_HSLOT_MAIN(hslot2)->hash4_cnt--;
203}
204#endif /* CONFIG_BASE_SMALL */
205
206extern struct proto udp_prot;
207
208DECLARE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
209
210/* sysctl variables for udp */
211extern long sysctl_udp_mem[3];
212extern int sysctl_udp_rmem_min;
213extern int sysctl_udp_wmem_min;
214
215struct sk_buff;
216
217/*
218 * Generic checksumming routines for UDP(-Lite) v4 and v6
219 */
220static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
221{
222 return (UDP_SKB_CB(skb)->cscov == skb->len ?
223 __skb_checksum_complete(skb) :
224 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
225}
226
227static inline int udp_lib_checksum_complete(struct sk_buff *skb)
228{
229 return !skb_csum_unnecessary(skb) &&
230 __udp_lib_checksum_complete(skb);
231}
232
233/**
234 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
235 * @sk: socket we are writing to
236 * @skb: sk_buff containing the filled-in UDP header
237 * (checksum field must be zeroed out)
238 */
239static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
240{
241 __wsum csum = csum_partial(buff: skb_transport_header(skb),
242 len: sizeof(struct udphdr), sum: 0);
243 skb_queue_walk(&sk->sk_write_queue, skb) {
244 csum = csum_add(csum, addend: skb->csum);
245 }
246 return csum;
247}
248
249static inline __wsum udp_csum(struct sk_buff *skb)
250{
251 __wsum csum = csum_partial(buff: skb_transport_header(skb),
252 len: sizeof(struct udphdr), sum: skb->csum);
253
254 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
255 csum = csum_add(csum, addend: skb->csum);
256 }
257 return csum;
258}
259
260static inline __sum16 udp_v4_check(int len, __be32 saddr,
261 __be32 daddr, __wsum base)
262{
263 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, sum: base);
264}
265
266void udp_set_csum(bool nocheck, struct sk_buff *skb,
267 __be32 saddr, __be32 daddr, int len);
268
269static inline void udp_csum_pull_header(struct sk_buff *skb)
270{
271 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
272 skb->csum = csum_partial(buff: skb->data, len: sizeof(struct udphdr),
273 sum: skb->csum);
274 skb_pull_rcsum(skb, len: sizeof(struct udphdr));
275 UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
276}
277
278typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
279 __be16 dport);
280
281void udp_v6_early_demux(struct sk_buff *skb);
282INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
283
284struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
285 netdev_features_t features, bool is_ipv6);
286
287static inline int udp_lib_init_sock(struct sock *sk)
288{
289 struct udp_sock *up = udp_sk(sk);
290
291 sk->sk_drop_counters = &up->drop_counters;
292 skb_queue_head_init(list: &up->reader_queue);
293 INIT_HLIST_NODE(h: &up->tunnel_list);
294 up->forward_threshold = sk->sk_rcvbuf >> 2;
295 set_bit(nr: SOCK_CUSTOM_SOCKOPT, addr: &sk->sk_socket->flags);
296
297 up->udp_prod_queue = kcalloc(nr_node_ids, sizeof(*up->udp_prod_queue),
298 GFP_KERNEL);
299 if (!up->udp_prod_queue)
300 return -ENOMEM;
301 for (int i = 0; i < nr_node_ids; i++)
302 init_llist_head(list: &up->udp_prod_queue[i].ll_root);
303 return 0;
304}
305
306static inline void udp_drops_inc(struct sock *sk)
307{
308 numa_drop_add(ndc: &udp_sk(sk)->drop_counters, val: 1);
309}
310
311/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
312static inline int udp_lib_hash(struct sock *sk)
313{
314 BUG();
315 return 0;
316}
317
318void udp_lib_unhash(struct sock *sk);
319void udp_lib_rehash(struct sock *sk, u16 new_hash, u16 new_hash4);
320u32 udp_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport,
321 const __be32 faddr, const __be16 fport);
322
323static inline void udp_lib_close(struct sock *sk, long timeout)
324{
325 sk_common_release(sk);
326}
327
328/* hash4 routines shared between UDPv4/6 */
329#if IS_ENABLED(CONFIG_BASE_SMALL)
330static inline void udp_lib_hash4(struct sock *sk, u16 hash)
331{
332}
333
334static inline void udp4_hash4(struct sock *sk)
335{
336}
337#else /* !CONFIG_BASE_SMALL */
338void udp_lib_hash4(struct sock *sk, u16 hash);
339void udp4_hash4(struct sock *sk);
340#endif /* CONFIG_BASE_SMALL */
341
342int udp_lib_get_port(struct sock *sk, unsigned short snum,
343 unsigned int hash2_nulladdr);
344
345u32 udp_flow_hashrnd(void);
346
347static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
348 int min, int max, bool use_eth)
349{
350 u32 hash;
351
352 if (min >= max) {
353 /* Use default range */
354 inet_get_local_port_range(net, low: &min, high: &max);
355 }
356
357 hash = skb_get_hash(skb);
358 if (unlikely(!hash)) {
359 if (use_eth) {
360 /* Can't find a normal hash, caller has indicated an
361 * Ethernet packet so use that to compute a hash.
362 */
363 hash = jhash(key: skb->data, length: 2 * ETH_ALEN,
364 initval: (__force u32) skb->protocol);
365 } else {
366 /* Can't derive any sort of hash for the packet, set
367 * to some consistent random value.
368 */
369 hash = udp_flow_hashrnd();
370 }
371 }
372
373 /* Since this is being sent on the wire obfuscate hash a bit
374 * to minimize possibility that any useful information to an
375 * attacker is leaked. Only upper 16 bits are relevant in the
376 * computation for 16 bit port value.
377 */
378 hash ^= hash << 16;
379
380 return htons((((u64) hash * (max - min)) >> 32) + min);
381}
382
383static inline int udp_rqueue_get(struct sock *sk)
384{
385 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
386}
387
388static inline bool udp_sk_bound_dev_eq(const struct net *net, int bound_dev_if,
389 int dif, int sdif)
390{
391#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
392 return inet_bound_dev_eq(l3mdev_accept: !!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
393 bound_dev_if, dif, sdif);
394#else
395 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
396#endif
397}
398
399/* net/ipv4/udp.c */
400void udp_destruct_common(struct sock *sk);
401void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
402int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
403void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
404struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off,
405 int *err);
406static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
407 int *err)
408{
409 int off = 0;
410
411 return __skb_recv_udp(sk, flags, off: &off, err);
412}
413
414enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb);
415bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
416int udp_err(struct sk_buff *, u32);
417int udp_abort(struct sock *sk, int err);
418int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
419void udp_splice_eof(struct socket *sock);
420int udp_push_pending_frames(struct sock *sk);
421void udp_flush_pending_frames(struct sock *sk);
422int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
423void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
424int udp_rcv(struct sk_buff *skb);
425int udp_ioctl(struct sock *sk, int cmd, int *karg);
426int udp_init_sock(struct sock *sk);
427int udp_pre_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len);
428int __udp_disconnect(struct sock *sk, int flags);
429int udp_disconnect(struct sock *sk, int flags);
430__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
431struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
432 netdev_features_t features,
433 bool is_ipv6);
434int udp_lib_getsockopt(struct sock *sk, int level, int optname,
435 char __user *optval, int __user *optlen);
436int udp_lib_setsockopt(struct sock *sk, int level, int optname,
437 sockptr_t optval, unsigned int optlen,
438 int (*push_pending_frames)(struct sock *));
439struct sock *udp4_lib_lookup(const struct net *net, __be32 saddr, __be16 sport,
440 __be32 daddr, __be16 dport, int dif);
441struct sock *__udp4_lib_lookup(const struct net *net, __be32 saddr,
442 __be16 sport,
443 __be32 daddr, __be16 dport, int dif, int sdif,
444 struct udp_table *tbl, struct sk_buff *skb);
445struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
446 __be16 sport, __be16 dport);
447struct sock *udp6_lib_lookup(const struct net *net,
448 const struct in6_addr *saddr, __be16 sport,
449 const struct in6_addr *daddr, __be16 dport,
450 int dif);
451struct sock *__udp6_lib_lookup(const struct net *net,
452 const struct in6_addr *saddr, __be16 sport,
453 const struct in6_addr *daddr, __be16 dport,
454 int dif, int sdif, struct udp_table *tbl,
455 struct sk_buff *skb);
456struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
457 __be16 sport, __be16 dport);
458int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
459
460/* UDP uses skb->dev_scratch to cache as much information as possible and avoid
461 * possibly multiple cache miss on dequeue()
462 */
463struct udp_dev_scratch {
464 /* skb->truesize and the stateless bit are embedded in a single field;
465 * do not use a bitfield since the compiler emits better/smaller code
466 * this way
467 */
468 u32 _tsize_state;
469
470#if BITS_PER_LONG == 64
471 /* len and the bit needed to compute skb_csum_unnecessary
472 * will be on cold cache lines at recvmsg time.
473 * skb->len can be stored on 16 bits since the udp header has been
474 * already validated and pulled.
475 */
476 u16 len;
477 bool is_linear;
478 bool csum_unnecessary;
479#endif
480};
481
482static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
483{
484 return (struct udp_dev_scratch *)&skb->dev_scratch;
485}
486
487#if BITS_PER_LONG == 64
488static inline unsigned int udp_skb_len(struct sk_buff *skb)
489{
490 return udp_skb_scratch(skb)->len;
491}
492
493static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
494{
495 return udp_skb_scratch(skb)->csum_unnecessary;
496}
497
498static inline bool udp_skb_is_linear(struct sk_buff *skb)
499{
500 return udp_skb_scratch(skb)->is_linear;
501}
502
503#else
504static inline unsigned int udp_skb_len(struct sk_buff *skb)
505{
506 return skb->len;
507}
508
509static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
510{
511 return skb_csum_unnecessary(skb);
512}
513
514static inline bool udp_skb_is_linear(struct sk_buff *skb)
515{
516 return !skb_is_nonlinear(skb);
517}
518#endif
519
520static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
521 struct iov_iter *to)
522{
523 return copy_to_iter_full(addr: skb->data + off, bytes: len, i: to) ? 0 : -EFAULT;
524}
525
526/*
527 * SNMP statistics for UDP and UDP-Lite
528 */
529#define UDP_INC_STATS(net, field, is_udplite) do { \
530 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
531 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
532#define __UDP_INC_STATS(net, field, is_udplite) do { \
533 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
534 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
535
536#define __UDP6_INC_STATS(net, field, is_udplite) do { \
537 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
538 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
539} while(0)
540#define UDP6_INC_STATS(net, field, __lite) do { \
541 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
542 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
543} while(0)
544
545#if IS_ENABLED(CONFIG_IPV6)
546#define __UDPX_MIB(sk, ipv4) \
547({ \
548 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
549 sock_net(sk)->mib.udp_statistics) : \
550 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
551 sock_net(sk)->mib.udp_stats_in6); \
552})
553#else
554#define __UDPX_MIB(sk, ipv4) \
555({ \
556 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
557 sock_net(sk)->mib.udp_statistics; \
558})
559#endif
560
561#define __UDPX_INC_STATS(sk, field) \
562 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
563
564#ifdef CONFIG_PROC_FS
565struct udp_seq_afinfo {
566 sa_family_t family;
567 struct udp_table *udp_table;
568};
569
570struct udp_iter_state {
571 struct seq_net_private p;
572 int bucket;
573};
574
575void *udp_seq_start(struct seq_file *seq, loff_t *pos);
576void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
577void udp_seq_stop(struct seq_file *seq, void *v);
578
579extern const struct seq_operations udp_seq_ops;
580extern const struct seq_operations udp6_seq_ops;
581
582int udp4_proc_init(void);
583void udp4_proc_exit(void);
584#endif /* CONFIG_PROC_FS */
585
586int udpv4_offload_init(void);
587
588void udp_init(void);
589
590DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
591void udp_encap_enable(void);
592void udp_encap_disable(void);
593#if IS_ENABLED(CONFIG_IPV6)
594DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
595void udpv6_encap_enable(void);
596#endif
597
598static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
599 struct sk_buff *skb, bool ipv4)
600{
601 netdev_features_t features = NETIF_F_SG;
602 struct sk_buff *segs;
603 int drop_count;
604
605 /*
606 * Segmentation in UDP receive path is only for UDP GRO, drop udp
607 * fragmentation offload (UFO) packets.
608 */
609 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) {
610 drop_count = 1;
611 goto drop;
612 }
613
614 /* Avoid csum recalculation by skb_segment unless userspace explicitly
615 * asks for the final checksum values
616 */
617 if (!inet_get_convert_csum(sk))
618 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
619
620 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
621 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
622 * packets in udp_gro_complete_segment. As does UDP GSO, verified by
623 * udp_send_skb. But when those packets are looped in dev_loopback_xmit
624 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
625 * Reset in this specific case, where PARTIAL is both correct and
626 * required.
627 */
628 if (skb->pkt_type == PACKET_LOOPBACK)
629 skb->ip_summed = CHECKSUM_PARTIAL;
630
631 /* the GSO CB lays after the UDP one, no need to save and restore any
632 * CB fragment
633 */
634 segs = __skb_gso_segment(skb, features, tx_path: false);
635 if (IS_ERR_OR_NULL(ptr: segs)) {
636 drop_count = skb_shinfo(skb)->gso_segs;
637 goto drop;
638 }
639
640 consume_skb(skb);
641 return segs;
642
643drop:
644 sk_drops_add(sk, segs: drop_count);
645 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, drop_count);
646 kfree_skb(skb);
647 return NULL;
648}
649
650static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
651{
652 /* UDP-lite can't land here - no GRO */
653 WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov);
654
655 /* UDP packets generated with UDP_SEGMENT and traversing:
656 *
657 * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
658 *
659 * can reach an UDP socket with CHECKSUM_NONE, because
660 * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
661 * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
662 * have a valid checksum, as the GRO engine validates the UDP csum
663 * before the aggregation and nobody strips such info in between.
664 * Instead of adding another check in the tunnel fastpath, we can force
665 * a valid csum after the segmentation.
666 * Additionally fixup the UDP CB.
667 */
668 UDP_SKB_CB(skb)->cscov = skb->len;
669 if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
670 skb->csum_valid = 1;
671}
672
673#ifdef CONFIG_BPF_SYSCALL
674struct sk_psock;
675int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
676#endif
677
678#endif /* _UDP_H */
679

source code of linux/include/net/udp.h