include/net/udp.h - kernel/msm-4.19 - Gitiles

 /*
  * INET		An implementation of the TCP/IP protocol suite for the LINUX
  *		operating system.  INET is implemented using the  BSD Socket
  *		interface as the means of communication with the user level.
  *
  *		Definitions for the UDP module.
  *
  * Version:	@(#)udp.h	1.0.2	05/07/93
  *
  * Authors:	Ross Biro
  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  *
  * Fixes:
  *		Alan Cox	: Turned on udp checksums. I don't want to
  *				  chase 'memory corruption' bugs that aren't!
  *
  *		This program is free software; you can redistribute it and/or
  *		modify it under the terms of the GNU General Public License
  *		as published by the Free Software Foundation; either version
  *		2 of the License, or (at your option) any later version.
  */
 #ifndef _UDP_H
 #define _UDP_H

 #include <linux/list.h>
 #include <linux/bug.h>
 #include <net/inet_sock.h>
 #include <net/sock.h>
 #include <net/snmp.h>
 #include <net/ip.h>
 #include <linux/ipv6.h>
 #include <linux/seq_file.h>
 #include <linux/poll.h>

 /**
  *	struct udp_skb_cb  -  UDP(-Lite) private variables
  *
  *	@header:      private variables used by IPv4/IPv6
  *	@cscov:       checksum coverage length (UDP-Lite only)
  *	@partial_cov: if set indicates partial csum coverage
  */
 struct udp_skb_cb {
 	union {
 		struct inet_skb_parm	h4;
 #if IS_ENABLED(CONFIG_IPV6)
 		struct inet6_skb_parm	h6;
 #endif
 	} header;
 	__u16		cscov;
 	__u8		partial_cov;
 };
 #define UDP_SKB_CB(__skb)	((struct udp_skb_cb *)((__skb)->cb))

 /**
  *	struct udp_hslot - UDP hash slot
  *
  *	@head:	head of list of sockets
  *	@count:	number of sockets in 'head' list
  *	@lock:	spinlock protecting changes to head/count
  */
 struct udp_hslot {
 	struct hlist_head	head;
 	int			count;
 	spinlock_t		lock;
 } __attribute__((aligned(2 * sizeof(long))));

 /**
  *	struct udp_table - UDP table
  *
  *	@hash:	hash table, sockets are hashed on (local port)
  *	@hash2:	hash table, sockets are hashed on (local port, local address)
  *	@mask:	number of slots in hash tables, minus 1
  *	@log:	log2(number of slots in hash table)
  */
 struct udp_table {
 	struct udp_hslot	*hash;
 	struct udp_hslot	*hash2;
 	unsigned int		mask;
 	unsigned int		log;
 };
 extern struct udp_table udp_table;
 void udp_table_init(struct udp_table *, const char *);
 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
 					     struct net *net, unsigned int num)
 {
 	return &table->hash[udp_hashfn(net, num, table->mask)];
 }
 /*
  * For secondary hash, net_hash_mix() is performed before calling
  * udp_hashslot2(), this explains difference with udp_hashslot()
  */
 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
 					      unsigned int hash)
 {
 	return &table->hash2[hash & table->mask];
 }

 extern struct proto udp_prot;

 extern atomic_long_t udp_memory_allocated;

 /* sysctl variables for udp */
 extern long sysctl_udp_mem[3];
 extern int sysctl_udp_rmem_min;
 extern int sysctl_udp_wmem_min;

 struct sk_buff;

 /*
  *	Generic checksumming routines for UDP(-Lite) v4 and v6
  */
 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
 {
 	return (UDP_SKB_CB(skb)->cscov == skb->len ?
 		__skb_checksum_complete(skb) :
 		__skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
 }

 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
 {
 	return !skb_csum_unnecessary(skb) &&
 		__udp_lib_checksum_complete(skb);
 }

 /**
  * 	udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
  * 	@sk: 	socket we are writing to
  * 	@skb: 	sk_buff containing the filled-in UDP header
  * 	        (checksum field must be zeroed out)
  */
 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
 {
 	__wsum csum = csum_partial(skb_transport_header(skb),
 				   sizeof(struct udphdr), 0);
 	skb_queue_walk(&sk->sk_write_queue, skb) {
 		csum = csum_add(csum, skb->csum);
 	}
 	return csum;
 }

 static inline __wsum udp_csum(struct sk_buff *skb)
 {
 	__wsum csum = csum_partial(skb_transport_header(skb),
 				   sizeof(struct udphdr), skb->csum);

 	for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
 		csum = csum_add(csum, skb->csum);
 	}
 	return csum;
 }

 static inline __sum16 udp_v4_check(int len, __be32 saddr,
 				   __be32 daddr, __wsum base)
 {
 	return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
 }

 void udp_set_csum(bool nocheck, struct sk_buff *skb,
 		  __be32 saddr, __be32 daddr, int len);

 static inline void udp_csum_pull_header(struct sk_buff *skb)
 {
 	if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
 		skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
 					 skb->csum);
 	skb_pull_rcsum(skb, sizeof(struct udphdr));
 	UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
 }

 typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
 				     __be16 dport);

 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
 				 struct udphdr *uh, udp_lookup_t lookup);
 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);

 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
 {
 	struct udphdr *uh;
 	unsigned int hlen, off;

 	off  = skb_gro_offset(skb);
 	hlen = off + sizeof(*uh);
 	uh   = skb_gro_header_fast(skb, off);
 	if (skb_gro_header_hard(skb, hlen))
 		uh = skb_gro_header_slow(skb, hlen, off);

 	return uh;
 }

 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
 static inline int udp_lib_hash(struct sock *sk)
 {
 	BUG();
 	return 0;
 }

 void udp_lib_unhash(struct sock *sk);
 void udp_lib_rehash(struct sock *sk, u16 new_hash);

 static inline void udp_lib_close(struct sock *sk, long timeout)
 {
 	sk_common_release(sk);
 }

 int udp_lib_get_port(struct sock *sk, unsigned short snum,
 		     unsigned int hash2_nulladdr);

 u32 udp_flow_hashrnd(void);

 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
 				       int min, int max, bool use_eth)
 {
 	u32 hash;

 	if (min >= max) {
 		/* Use default range */
 		inet_get_local_port_range(net, &min, &max);
 	}

 	hash = skb_get_hash(skb);
 	if (unlikely(!hash)) {
 		if (use_eth) {
 			/* Can't find a normal hash, caller has indicated an
 			 * Ethernet packet so use that to compute a hash.
 			 */
 			hash = jhash(skb->data, 2 * ETH_ALEN,
 				     (__force u32) skb->protocol);
 		} else {
 			/* Can't derive any sort of hash for the packet, set
 			 * to some consistent random value.
 			 */
 			hash = udp_flow_hashrnd();
 		}
 	}

 	/* Since this is being sent on the wire obfuscate hash a bit
 	 * to minimize possbility that any useful information to an
 	 * attacker is leaked. Only upper 16 bits are relevant in the
 	 * computation for 16 bit port value.
 	 */
 	hash ^= hash << 16;

 	return htons((((u64) hash * (max - min)) >> 32) + min);
 }

 /* net/ipv4/udp.c */
 void udp_destruct_sock(struct sock *sk);
 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
 			       int noblock, int *peeked, int *off, int *err);
 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
 					   int noblock, int *err)
 {
 	int peeked, off = 0;

 	return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err);
 }

 void udp_v4_early_demux(struct sk_buff *skb);
 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
 int udp_get_port(struct sock *sk, unsigned short snum,
 		 int (*saddr_cmp)(const struct sock *,
 				  const struct sock *));
 void udp_err(struct sk_buff *, u32);
 int udp_abort(struct sock *sk, int err);
 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
 int udp_push_pending_frames(struct sock *sk);
 void udp_flush_pending_frames(struct sock *sk);
 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
 int udp_rcv(struct sk_buff *skb);
 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 int udp_init_sock(struct sock *sk);
 int __udp_disconnect(struct sock *sk, int flags);
 int udp_disconnect(struct sock *sk, int flags);
 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait);
 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 				       netdev_features_t features,
 				       bool is_ipv6);
 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 		       char __user *optval, int __user *optlen);
 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 		       char __user *optval, unsigned int optlen,
 		       int (*push_pending_frames)(struct sock *));
 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 			     __be32 daddr, __be16 dport, int dif);
 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 			       __be32 daddr, __be16 dport, int dif, int sdif,
 			       struct udp_table *tbl, struct sk_buff *skb);
 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
 				 __be16 sport, __be16 dport);
 struct sock *udp6_lib_lookup(struct net *net,
 			     const struct in6_addr *saddr, __be16 sport,
 			     const struct in6_addr *daddr, __be16 dport,
 			     int dif);
 struct sock *__udp6_lib_lookup(struct net *net,
 			       const struct in6_addr *saddr, __be16 sport,
 			       const struct in6_addr *daddr, __be16 dport,
 			       int dif, int sdif, struct udp_table *tbl,
 			       struct sk_buff *skb);
 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
 				 __be16 sport, __be16 dport);

 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
  * possibly multiple cache miss on dequeue()
  */
 struct udp_dev_scratch {
 	/* skb->truesize and the stateless bit are embedded in a single field;
 	 * do not use a bitfield since the compiler emits better/smaller code
 	 * this way
 	 */
 	u32 _tsize_state;

 #if BITS_PER_LONG == 64
 	/* len and the bit needed to compute skb_csum_unnecessary
 	 * will be on cold cache lines at recvmsg time.
 	 * skb->len can be stored on 16 bits since the udp header has been
 	 * already validated and pulled.
 	 */
 	u16 len;
 	bool is_linear;
 	bool csum_unnecessary;
 #endif
 };

 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
 {
 	return (struct udp_dev_scratch *)&skb->dev_scratch;
 }

 #if BITS_PER_LONG == 64
 static inline unsigned int udp_skb_len(struct sk_buff *skb)
 {
 	return udp_skb_scratch(skb)->len;
 }

 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
 {
 	return udp_skb_scratch(skb)->csum_unnecessary;
 }

 static inline bool udp_skb_is_linear(struct sk_buff *skb)
 {
 	return udp_skb_scratch(skb)->is_linear;
 }

 #else
 static inline unsigned int udp_skb_len(struct sk_buff *skb)
 {
 	return skb->len;
 }

 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
 {
 	return skb_csum_unnecessary(skb);
 }

 static inline bool udp_skb_is_linear(struct sk_buff *skb)
 {
 	return !skb_is_nonlinear(skb);
 }
 #endif

 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
 				  struct iov_iter *to)
 {
 	int n;

 	n = copy_to_iter(skb->data + off, len, to);
 	if (n == len)
 		return 0;

 	iov_iter_revert(to, n);
 	return -EFAULT;
 }

 /*
  * 	SNMP statistics for UDP and UDP-Lite
  */
 #define UDP_INC_STATS(net, field, is_udplite)		      do { \
 	if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field);       \
 	else		SNMP_INC_STATS((net)->mib.udp_statistics, field);  }  while(0)
 #define __UDP_INC_STATS(net, field, is_udplite) 	      do { \
 	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field);         \
 	else		__SNMP_INC_STATS((net)->mib.udp_statistics, field);    }  while(0)

 #define __UDP6_INC_STATS(net, field, is_udplite)	    do { \
 	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
 	else		__SNMP_INC_STATS((net)->mib.udp_stats_in6, field);  \
 } while(0)
 #define UDP6_INC_STATS(net, field, __lite)		    do { \
 	if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);  \
 	else	    SNMP_INC_STATS((net)->mib.udp_stats_in6, field);      \
 } while(0)

 #if IS_ENABLED(CONFIG_IPV6)
 #define __UDPX_INC_STATS(sk, field)					\
 do {									\
 	if ((sk)->sk_family == AF_INET)					\
 		__UDP_INC_STATS(sock_net(sk), field, 0);		\
 	else								\
 		__UDP6_INC_STATS(sock_net(sk), field, 0);		\
 } while (0)
 #else
 #define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0)
 #endif

 /* /proc */
 int udp_seq_open(struct inode *inode, struct file *file);

 struct udp_seq_afinfo {
 	char				*name;
 	sa_family_t			family;
 	struct udp_table		*udp_table;
 	const struct file_operations	*seq_fops;
 	struct seq_operations		seq_ops;
 };

 struct udp_iter_state {
 	struct seq_net_private  p;
 	sa_family_t		family;
 	int			bucket;
 	struct udp_table	*udp_table;
 };

 #ifdef CONFIG_PROC_FS
 int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
 void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);

 int udp4_proc_init(void);
 void udp4_proc_exit(void);
 #endif

 int udpv4_offload_init(void);

 void udp_init(void);

 void udp_encap_enable(void);
 #if IS_ENABLED(CONFIG_IPV6)
 void udpv6_encap_enable(void);
 #endif

 #endif	/* _UDP_H */
	/*
	* INET An implementation of the TCP/IP protocol suite for the LINUX
	* operating system. INET is implemented using the BSD Socket
	* interface as the means of communication with the user level.
	*
	* Definitions for the UDP module.
	*
	* Version: @(#)udp.h 1.0.2 05/07/93
	*
	* Authors: Ross Biro
	* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
	*
	* Fixes:
	* Alan Cox : Turned on udp checksums. I don't want to
	* chase 'memory corruption' bugs that aren't!
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/
	#ifndef _UDP_H
	#define _UDP_H

	#include <linux/list.h>
	#include <linux/bug.h>
	#include <net/inet_sock.h>
	#include <net/sock.h>
	#include <net/snmp.h>
	#include <net/ip.h>
	#include <linux/ipv6.h>
	#include <linux/seq_file.h>
	#include <linux/poll.h>

	/**
	* struct udp_skb_cb - UDP(-Lite) private variables
	*
	* @header: private variables used by IPv4/IPv6
	* @cscov: checksum coverage length (UDP-Lite only)
	* @partial_cov: if set indicates partial csum coverage
	*/
	struct udp_skb_cb {
	union {
	struct inet_skb_parm h4;
	#if IS_ENABLED(CONFIG_IPV6)
	struct inet6_skb_parm h6;
	#endif
	} header;
	__u16 cscov;
	__u8 partial_cov;
	};
	#define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))

	/**
	* struct udp_hslot - UDP hash slot
	*
	* @head: head of list of sockets
	* @count: number of sockets in 'head' list
	* @lock: spinlock protecting changes to head/count
	*/
	struct udp_hslot {
	struct hlist_head head;
	int count;
	spinlock_t lock;
	} __attribute__((aligned(2 * sizeof(long))));

	/**
	* struct udp_table - UDP table
	*
	* @hash: hash table, sockets are hashed on (local port)
	* @hash2: hash table, sockets are hashed on (local port, local address)
	* @mask: number of slots in hash tables, minus 1
	* @log: log2(number of slots in hash table)
	*/
	struct udp_table {
	struct udp_hslot *hash;
	struct udp_hslot *hash2;
	unsigned int mask;
	unsigned int log;
	};
	extern struct udp_table udp_table;
	void udp_table_init(struct udp_table , const char );
	static inline struct udp_hslot udp_hashslot(struct udp_table table,
	struct net *net, unsigned int num)
	{
	return &table->hash[udp_hashfn(net, num, table->mask)];
	}
	/*
	* For secondary hash, net_hash_mix() is performed before calling
	* udp_hashslot2(), this explains difference with udp_hashslot()
	*/
	static inline struct udp_hslot udp_hashslot2(struct udp_table table,
	unsigned int hash)
	{
	return &table->hash2[hash & table->mask];
	}

	extern struct proto udp_prot;

	extern atomic_long_t udp_memory_allocated;

	/* sysctl variables for udp */
	extern long sysctl_udp_mem[3];
	extern int sysctl_udp_rmem_min;
	extern int sysctl_udp_wmem_min;

	struct sk_buff;

	/*
	* Generic checksumming routines for UDP(-Lite) v4 and v6
	*/
	static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
	{
	return (UDP_SKB_CB(skb)->cscov == skb->len ?
	__skb_checksum_complete(skb) :
	__skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
	}

	static inline int udp_lib_checksum_complete(struct sk_buff *skb)
	{
	return !skb_csum_unnecessary(skb) &&
	__udp_lib_checksum_complete(skb);
	}

	/**
	* udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
	* @sk: socket we are writing to
	* @skb: sk_buff containing the filled-in UDP header
	* (checksum field must be zeroed out)
	*/
	static inline __wsum udp_csum_outgoing(struct sock sk, struct sk_buff skb)
	{
	__wsum csum = csum_partial(skb_transport_header(skb),
	sizeof(struct udphdr), 0);
	skb_queue_walk(&sk->sk_write_queue, skb) {
	csum = csum_add(csum, skb->csum);
	}
	return csum;
	}

	static inline __wsum udp_csum(struct sk_buff *skb)
	{
	__wsum csum = csum_partial(skb_transport_header(skb),
	sizeof(struct udphdr), skb->csum);

	for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
	csum = csum_add(csum, skb->csum);
	}
	return csum;
	}

	static inline __sum16 udp_v4_check(int len, __be32 saddr,
	__be32 daddr, __wsum base)
	{
	return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
	}

	void udp_set_csum(bool nocheck, struct sk_buff *skb,
	__be32 saddr, __be32 daddr, int len);

	static inline void udp_csum_pull_header(struct sk_buff *skb)
	{
	if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
	skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
	skb->csum);
	skb_pull_rcsum(skb, sizeof(struct udphdr));
	UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
	}

	typedef struct sock (udp_lookup_t)(struct sk_buff *skb, __be16 sport,
	__be16 dport);

	struct sk_buff udp_gro_receive(struct sk_buff head, struct sk_buff *skb,
	struct udphdr *uh, udp_lookup_t lookup);
	int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);

	static inline struct udphdr udp_gro_udphdr(struct sk_buff skb)
	{
	struct udphdr *uh;
	unsigned int hlen, off;

	off = skb_gro_offset(skb);
	hlen = off + sizeof(*uh);
	uh = skb_gro_header_fast(skb, off);
	if (skb_gro_header_hard(skb, hlen))
	uh = skb_gro_header_slow(skb, hlen, off);

	return uh;
	}

	/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
	static inline int udp_lib_hash(struct sock *sk)
	{
	BUG();
	return 0;
	}

	void udp_lib_unhash(struct sock *sk);
	void udp_lib_rehash(struct sock *sk, u16 new_hash);

	static inline void udp_lib_close(struct sock *sk, long timeout)
	{
	sk_common_release(sk);
	}

	int udp_lib_get_port(struct sock *sk, unsigned short snum,
	unsigned int hash2_nulladdr);

	u32 udp_flow_hashrnd(void);

	static inline __be16 udp_flow_src_port(struct net net, struct sk_buff skb,
	int min, int max, bool use_eth)
	{
	u32 hash;

	if (min >= max) {
	/* Use default range */
	inet_get_local_port_range(net, &min, &max);
	}

	hash = skb_get_hash(skb);
	if (unlikely(!hash)) {
	if (use_eth) {
	/* Can't find a normal hash, caller has indicated an
	* Ethernet packet so use that to compute a hash.
	*/
	hash = jhash(skb->data, 2 * ETH_ALEN,
	(__force u32) skb->protocol);
	} else {
	/* Can't derive any sort of hash for the packet, set
	* to some consistent random value.
	*/
	hash = udp_flow_hashrnd();
	}
	}

	/* Since this is being sent on the wire obfuscate hash a bit
	* to minimize possbility that any useful information to an
	* attacker is leaked. Only upper 16 bits are relevant in the
	* computation for 16 bit port value.
	*/
	hash ^= hash << 16;

	return htons((((u64) hash * (max - min)) >> 32) + min);
	}

	/* net/ipv4/udp.c */
	void udp_destruct_sock(struct sock *sk);
	void skb_consume_udp(struct sock sk, struct sk_buff skb, int len);
	int __udp_enqueue_schedule_skb(struct sock sk, struct sk_buff skb);
	void udp_skb_destructor(struct sock sk, struct sk_buff skb);
	struct sk_buff __skb_recv_udp(struct sock sk, unsigned int flags,
	int noblock, int peeked, int off, int *err);
	static inline struct sk_buff skb_recv_udp(struct sock sk, unsigned int flags,
	int noblock, int *err)
	{
	int peeked, off = 0;

	return __skb_recv_udp(sk, flags, noblock, &peeked, &off, err);
	}

	void udp_v4_early_demux(struct sk_buff *skb);
	bool udp_sk_rx_dst_set(struct sock sk, struct dst_entry dst);
	int udp_get_port(struct sock *sk, unsigned short snum,
	int (saddr_cmp)(const struct sock ,
	const struct sock *));
	void udp_err(struct sk_buff *, u32);
	int udp_abort(struct sock *sk, int err);
	int udp_sendmsg(struct sock sk, struct msghdr msg, size_t len);
	int udp_push_pending_frames(struct sock *sk);
	void udp_flush_pending_frames(struct sock *sk);
	void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
	int udp_rcv(struct sk_buff *skb);
	int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
	int udp_init_sock(struct sock *sk);
	int __udp_disconnect(struct sock *sk, int flags);
	int udp_disconnect(struct sock *sk, int flags);
	unsigned int udp_poll(struct file file, struct socket sock, poll_table *wait);
	struct sk_buff skb_udp_tunnel_segment(struct sk_buff skb,
	netdev_features_t features,
	bool is_ipv6);
	int udp_lib_getsockopt(struct sock *sk, int level, int optname,
	char __user optval, int __user optlen);
	int udp_lib_setsockopt(struct sock *sk, int level, int optname,
	char __user *optval, unsigned int optlen,
	int (push_pending_frames)(struct sock ));
	struct sock udp4_lib_lookup(struct net net, __be32 saddr, __be16 sport,
	__be32 daddr, __be16 dport, int dif);
	struct sock __udp4_lib_lookup(struct net net, __be32 saddr, __be16 sport,
	__be32 daddr, __be16 dport, int dif, int sdif,
	struct udp_table tbl, struct sk_buff skb);
	struct sock udp4_lib_lookup_skb(struct sk_buff skb,
	__be16 sport, __be16 dport);
	struct sock udp6_lib_lookup(struct net net,
	const struct in6_addr *saddr, __be16 sport,
	const struct in6_addr *daddr, __be16 dport,
	int dif);
	struct sock __udp6_lib_lookup(struct net net,
	const struct in6_addr *saddr, __be16 sport,
	const struct in6_addr *daddr, __be16 dport,
	int dif, int sdif, struct udp_table *tbl,
	struct sk_buff *skb);
	struct sock udp6_lib_lookup_skb(struct sk_buff skb,
	__be16 sport, __be16 dport);

	/* UDP uses skb->dev_scratch to cache as much information as possible and avoid
	* possibly multiple cache miss on dequeue()
	*/
	struct udp_dev_scratch {
	/* skb->truesize and the stateless bit are embedded in a single field;
	* do not use a bitfield since the compiler emits better/smaller code
	* this way
	*/
	u32 _tsize_state;

	#if BITS_PER_LONG == 64
	/* len and the bit needed to compute skb_csum_unnecessary
	* will be on cold cache lines at recvmsg time.
	* skb->len can be stored on 16 bits since the udp header has been
	* already validated and pulled.
	*/
	u16 len;
	bool is_linear;
	bool csum_unnecessary;
	#endif
	};

	static inline struct udp_dev_scratch udp_skb_scratch(struct sk_buff skb)
	{
	return (struct udp_dev_scratch *)&skb->dev_scratch;
	}

	#if BITS_PER_LONG == 64
	static inline unsigned int udp_skb_len(struct sk_buff *skb)
	{
	return udp_skb_scratch(skb)->len;
	}

	static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
	{
	return udp_skb_scratch(skb)->csum_unnecessary;
	}

	static inline bool udp_skb_is_linear(struct sk_buff *skb)
	{
	return udp_skb_scratch(skb)->is_linear;
	}

	#else
	static inline unsigned int udp_skb_len(struct sk_buff *skb)
	{
	return skb->len;
	}

	static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
	{
	return skb_csum_unnecessary(skb);
	}

	static inline bool udp_skb_is_linear(struct sk_buff *skb)
	{
	return !skb_is_nonlinear(skb);
	}
	#endif

	static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
	struct iov_iter *to)
	{
	int n;

	n = copy_to_iter(skb->data + off, len, to);
	if (n == len)
	return 0;

	iov_iter_revert(to, n);
	return -EFAULT;
	}

	/*
	* SNMP statistics for UDP and UDP-Lite
	*/
	#define UDP_INC_STATS(net, field, is_udplite) do { \
	if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
	else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
	#define __UDP_INC_STATS(net, field, is_udplite) do { \
	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
	else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)

	#define __UDP6_INC_STATS(net, field, is_udplite) do { \
	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
	else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
	} while(0)
	#define UDP6_INC_STATS(net, field, __lite) do { \
	if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
	else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
	} while(0)

	#if IS_ENABLED(CONFIG_IPV6)
	#define __UDPX_INC_STATS(sk, field) \
	do { \
	if ((sk)->sk_family == AF_INET) \
	__UDP_INC_STATS(sock_net(sk), field, 0); \
	else \
	__UDP6_INC_STATS(sock_net(sk), field, 0); \
	} while (0)
	#else
	#define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0)
	#endif

	/* /proc */
	int udp_seq_open(struct inode inode, struct file file);

	struct udp_seq_afinfo {
	char *name;
	sa_family_t family;
	struct udp_table *udp_table;
	const struct file_operations *seq_fops;
	struct seq_operations seq_ops;
	};

	struct udp_iter_state {
	struct seq_net_private p;
	sa_family_t family;
	int bucket;
	struct udp_table *udp_table;
	};

	#ifdef CONFIG_PROC_FS
	int udp_proc_register(struct net net, struct udp_seq_afinfo afinfo);
	void udp_proc_unregister(struct net net, struct udp_seq_afinfo afinfo);

	int udp4_proc_init(void);
	void udp4_proc_exit(void);
	#endif

	int udpv4_offload_init(void);

	void udp_init(void);

	void udp_encap_enable(void);
	#if IS_ENABLED(CONFIG_IPV6)
	void udpv6_encap_enable(void);
	#endif

	#endif /* _UDP_H */