udp.h

  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 = 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(&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(&udp_sk(sk)->drop_counters, 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, &min, &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(skb->data, 2 * ETH_ALEN,
364				     (__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(!!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, 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(skb->data + off, len, 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, false);
635	if (IS_ERR_OR_NULL(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, 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 */