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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, 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(skb_transport_header(skb),
242 sizeof(struct udphdr), 0);
243 skb_queue_walk(&sk->sk_write_queue, skb) {
244 csum = csum_add(csum, skb->csum);
245 }
246 return csum;
247}
248
249static inline __wsum udp_csum(struct sk_buff *skb)
250{
251 __wsum csum = csum_partial(skb_transport_header(skb),
252 sizeof(struct udphdr), skb->csum);
253
254 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
255 csum = csum_add(csum, 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, 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(skb->data, sizeof(struct udphdr),
273 skb->csum);
274 skb_pull_rcsum(skb, 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(&up->reader_queue);
293 INIT_HLIST_NODE(&up->tunnel_list);
294 up->forward_threshold = sk->sk_rcvbuf >> 2;
295 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
296
297 up->udp_prod_queue = kzalloc_objs(*up->udp_prod_queue, nr_node_ids);
298 if (!up->udp_prod_queue)
299 return -ENOMEM;
300 for (int i = 0; i < nr_node_ids; i++)
301 init_llist_head(&up->udp_prod_queue[i].ll_root);
302 return 0;
303}
304
305static inline void udp_drops_inc(struct sock *sk)
306{
307 numa_drop_add(&udp_sk(sk)->drop_counters, 1);
308}
309
310/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
311static inline int udp_lib_hash(struct sock *sk)
312{
313 BUG();
314 return 0;
315}
316
317void udp_lib_unhash(struct sock *sk);
318void udp_lib_rehash(struct sock *sk, u16 new_hash, u16 new_hash4);
319u32 udp_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport,
320 const __be32 faddr, const __be16 fport);
321
322static inline void udp_lib_close(struct sock *sk, long timeout)
323{
324 sk_common_release(sk);
325}
326
327/* hash4 routines shared between UDPv4/6 */
328#if IS_ENABLED(CONFIG_BASE_SMALL)
329static inline void udp_lib_hash4(struct sock *sk, u16 hash)
330{
331}
332
333static inline void udp4_hash4(struct sock *sk)
334{
335}
336#else /* !CONFIG_BASE_SMALL */
337void udp_lib_hash4(struct sock *sk, u16 hash);
338void udp4_hash4(struct sock *sk);
339#endif /* CONFIG_BASE_SMALL */
340
341int udp_lib_get_port(struct sock *sk, unsigned short snum,
342 unsigned int hash2_nulladdr);
343
344u32 udp_flow_hashrnd(void);
345
346static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
347 int min, int max, bool use_eth)
348{
349 u32 hash;
350
351 if (min >= max) {
352 /* Use default range */
353 inet_get_local_port_range(net, &min, &max);
354 }
355
356 hash = skb_get_hash(skb);
357 if (unlikely(!hash)) {
358 if (use_eth) {
359 /* Can't find a normal hash, caller has indicated an
360 * Ethernet packet so use that to compute a hash.
361 */
362 hash = jhash(skb->data, 2 * ETH_ALEN,
363 (__force u32) skb->protocol);
364 } else {
365 /* Can't derive any sort of hash for the packet, set
366 * to some consistent random value.
367 */
368 hash = udp_flow_hashrnd();
369 }
370 }
371
372 /* Since this is being sent on the wire obfuscate hash a bit
373 * to minimize possibility that any useful information to an
374 * attacker is leaked. Only upper 16 bits are relevant in the
375 * computation for 16 bit port value.
376 */
377 hash ^= hash << 16;
378
379 return htons((((u64) hash * (max - min)) >> 32) + min);
380}
381
382static inline int udp_rqueue_get(struct sock *sk)
383{
384 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
385}
386
387static inline bool udp_sk_bound_dev_eq(const struct net *net, int bound_dev_if,
388 int dif, int sdif)
389{
390#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
391 return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
392 bound_dev_if, dif, sdif);
393#else
394 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
395#endif
396}
397
398/* net/ipv4/udp.c */
399void udp_destruct_common(struct sock *sk);
400void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
401int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
402void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
403struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off,
404 int *err);
405static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
406 int *err)
407{
408 int off = 0;
409
410 return __skb_recv_udp(sk, flags, &off, err);
411}
412
413enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb);
414bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
415int udp_err(struct sk_buff *, u32);
416int udp_abort(struct sock *sk, int err);
417int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
418void udp_splice_eof(struct socket *sock);
419int udp_push_pending_frames(struct sock *sk);
420void udp_flush_pending_frames(struct sock *sk);
421int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
422void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
423int udp_rcv(struct sk_buff *skb);
424int udp_ioctl(struct sock *sk, int cmd, int *karg);
425int udp_init_sock(struct sock *sk);
426int udp_pre_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len);
427int __udp_disconnect(struct sock *sk, int flags);
428int udp_disconnect(struct sock *sk, int flags);
429__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
430struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
431 netdev_features_t features,
432 bool is_ipv6);
433int udp_lib_getsockopt(struct sock *sk, int level, int optname,
434 char __user *optval, int __user *optlen);
435int udp_lib_setsockopt(struct sock *sk, int level, int optname,
436 sockptr_t optval, unsigned int optlen,
437 int (*push_pending_frames)(struct sock *));
438struct sock *udp4_lib_lookup(const struct net *net, __be32 saddr, __be16 sport,
439 __be32 daddr, __be16 dport, int dif);
440struct sock *__udp4_lib_lookup(const struct net *net, __be32 saddr,
441 __be16 sport,
442 __be32 daddr, __be16 dport, int dif, int sdif,
443 struct udp_table *tbl, struct sk_buff *skb);
444struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
445 __be16 sport, __be16 dport);
446struct sock *udp6_lib_lookup(const struct net *net,
447 const struct in6_addr *saddr, __be16 sport,
448 const struct in6_addr *daddr, __be16 dport,
449 int dif);
450struct sock *__udp6_lib_lookup(const struct net *net,
451 const struct in6_addr *saddr, __be16 sport,
452 const struct in6_addr *daddr, __be16 dport,
453 int dif, int sdif, struct udp_table *tbl,
454 struct sk_buff *skb);
455struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
456 __be16 sport, __be16 dport);
457int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
458
459/* UDP uses skb->dev_scratch to cache as much information as possible and avoid
460 * possibly multiple cache miss on dequeue()
461 */
462struct udp_dev_scratch {
463 /* skb->truesize and the stateless bit are embedded in a single field;
464 * do not use a bitfield since the compiler emits better/smaller code
465 * this way
466 */
467 u32 _tsize_state;
468
469#if BITS_PER_LONG == 64
470 /* len and the bit needed to compute skb_csum_unnecessary
471 * will be on cold cache lines at recvmsg time.
472 * skb->len can be stored on 16 bits since the udp header has been
473 * already validated and pulled.
474 */
475 u16 len;
476 bool is_linear;
477 bool csum_unnecessary;
478#endif
479};
480
481static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
482{
483 return (struct udp_dev_scratch *)&skb->dev_scratch;
484}
485
486#if BITS_PER_LONG == 64
487static inline unsigned int udp_skb_len(struct sk_buff *skb)
488{
489 return udp_skb_scratch(skb)->len;
490}
491
492static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
493{
494 return udp_skb_scratch(skb)->csum_unnecessary;
495}
496
497static inline bool udp_skb_is_linear(struct sk_buff *skb)
498{
499 return udp_skb_scratch(skb)->is_linear;
500}
501
502#else
503static inline unsigned int udp_skb_len(struct sk_buff *skb)
504{
505 return skb->len;
506}
507
508static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
509{
510 return skb_csum_unnecessary(skb);
511}
512
513static inline bool udp_skb_is_linear(struct sk_buff *skb)
514{
515 return !skb_is_nonlinear(skb);
516}
517#endif
518
519static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
520 struct iov_iter *to)
521{
522 return copy_to_iter_full(skb->data + off, len, to) ? 0 : -EFAULT;
523}
524
525/*
526 * SNMP statistics for UDP and UDP-Lite
527 */
528#define UDP_INC_STATS(net, field, is_udplite) do { \
529 if (unlikely(is_udplite)) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
530 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
531#define __UDP_INC_STATS(net, field, is_udplite) do { \
532 if (unlikely(is_udplite)) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
533 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
534
535#define __UDP6_INC_STATS(net, field, is_udplite) do { \
536 if (unlikely(is_udplite)) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
537 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
538} while(0)
539#define UDP6_INC_STATS(net, field, __lite) do { \
540 if (unlikely(__lite)) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
541 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
542} while(0)
543
544#if IS_ENABLED(CONFIG_IPV6)
545#define __UDPX_MIB(sk, ipv4) \
546({ \
547 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
548 sock_net(sk)->mib.udp_statistics) : \
549 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
550 sock_net(sk)->mib.udp_stats_in6); \
551})
552#else
553#define __UDPX_MIB(sk, ipv4) \
554({ \
555 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
556 sock_net(sk)->mib.udp_statistics; \
557})
558#endif
559
560#define __UDPX_INC_STATS(sk, field) \
561 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
562
563#ifdef CONFIG_PROC_FS
564struct udp_seq_afinfo {
565 sa_family_t family;
566 struct udp_table *udp_table;
567};
568
569struct udp_iter_state {
570 struct seq_net_private p;
571 int bucket;
572};
573
574void *udp_seq_start(struct seq_file *seq, loff_t *pos);
575void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
576void udp_seq_stop(struct seq_file *seq, void *v);
577
578extern const struct seq_operations udp_seq_ops;
579extern const struct seq_operations udp6_seq_ops;
580
581int udp4_proc_init(void);
582void udp4_proc_exit(void);
583#endif /* CONFIG_PROC_FS */
584
585int udpv4_offload_init(void);
586
587void udp_init(void);
588
589DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
590void udp_encap_enable(void);
591void udp_encap_disable(void);
592#if IS_ENABLED(CONFIG_IPV6)
593DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
594void udpv6_encap_enable(void);
595#endif
596
597static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
598 struct sk_buff *skb, bool ipv4)
599{
600 netdev_features_t features = NETIF_F_SG;
601 struct sk_buff *segs;
602 int drop_count;
603
604 /*
605 * Segmentation in UDP receive path is only for UDP GRO, drop udp
606 * fragmentation offload (UFO) packets.
607 */
608 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) {
609 drop_count = 1;
610 goto drop;
611 }
612
613 /* Avoid csum recalculation by skb_segment unless userspace explicitly
614 * asks for the final checksum values
615 */
616 if (!inet_get_convert_csum(sk))
617 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
618
619 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
620 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
621 * packets in udp_gro_complete_segment. As does UDP GSO, verified by
622 * udp_send_skb. But when those packets are looped in dev_loopback_xmit
623 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
624 * Reset in this specific case, where PARTIAL is both correct and
625 * required.
626 */
627 if (skb->pkt_type == PACKET_LOOPBACK)
628 skb->ip_summed = CHECKSUM_PARTIAL;
629
630 /* the GSO CB lays after the UDP one, no need to save and restore any
631 * CB fragment
632 */
633 segs = __skb_gso_segment(skb, features, false);
634 if (IS_ERR_OR_NULL(segs)) {
635 drop_count = skb_shinfo(skb)->gso_segs;
636 goto drop;
637 }
638
639 consume_skb(skb);
640 return segs;
641
642drop:
643 sk_drops_add(sk, drop_count);
644 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, drop_count);
645 kfree_skb(skb);
646 return NULL;
647}
648
649static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
650{
651 /* UDP-lite can't land here - no GRO */
652 WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov);
653
654 /* UDP packets generated with UDP_SEGMENT and traversing:
655 *
656 * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
657 *
658 * can reach an UDP socket with CHECKSUM_NONE, because
659 * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
660 * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
661 * have a valid checksum, as the GRO engine validates the UDP csum
662 * before the aggregation and nobody strips such info in between.
663 * Instead of adding another check in the tunnel fastpath, we can force
664 * a valid csum after the segmentation.
665 * Additionally fixup the UDP CB.
666 */
667 UDP_SKB_CB(skb)->cscov = skb->len;
668 if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
669 skb->csum_valid = 1;
670}
671
672#ifdef CONFIG_BPF_SYSCALL
673struct sk_psock;
674int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
675#endif
676
677#endif /* _UDP_H */