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linux/include/net/udp.h
Eric Dumazet 30fff9231f udp: bind() optimisation 
UDP bind() can be O(N^2) in some pathological cases.

Thanks to secondary hash tables, we can make it O(N)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-10 20:54:38 -08:00

248 lines
7.3 KiB
C
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/*
* 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 <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 defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
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_nulls_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;
extern void udp_table_init(struct udp_table *, const char *);
static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
struct net *net, unsigned 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];
}
/* Note: this must match 'valbool' in sock_setsockopt */
#define UDP_CSUM_NOXMIT 1
/* Used by SunRPC/xprt layer. */
#define UDP_CSUM_NORCV 2
/* Default, as per the RFC, is to always do csums. */
#define UDP_CSUM_DEFAULT 0
extern struct proto udp_prot;
extern atomic_t udp_memory_allocated;
/* sysctl variables for udp */
extern int 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 __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;
}
/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
static inline void udp_lib_hash(struct sock *sk)
{
BUG();
}
extern void udp_lib_unhash(struct sock *sk);
static inline void udp_lib_close(struct sock *sk, long timeout)
{
sk_common_release(sk);
}
extern int udp_lib_get_port(struct sock *sk, unsigned short snum,
int (*)(const struct sock *,const struct sock *),
unsigned int hash2_nulladdr);
/* net/ipv4/udp.c */
extern int udp_get_port(struct sock *sk, unsigned short snum,
int (*saddr_cmp)(const struct sock *, const struct sock *));
extern void udp_err(struct sk_buff *, u32);
extern int udp_sendmsg(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg, size_t len);
extern void udp_flush_pending_frames(struct sock *sk);
extern int udp_rcv(struct sk_buff *skb);
extern int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
extern int udp_disconnect(struct sock *sk, int flags);
extern unsigned int udp_poll(struct file *file, struct socket *sock,
poll_table *wait);
extern int udp_lib_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen);
extern int udp_lib_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen,
int (*push_pending_frames)(struct sock *));
extern struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
__be32 daddr, __be16 dport,
int dif);
/*
* SNMP statistics for UDP and UDP-Lite
*/
#define UDP_INC_STATS_USER(net, field, is_udplite) do { \
if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field); \
else SNMP_INC_STATS_USER((net)->mib.udp_statistics, field); } while(0)
#define UDP_INC_STATS_BH(net, field, is_udplite) do { \
if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field); \
else SNMP_INC_STATS_BH((net)->mib.udp_statistics, field); } while(0)
#define UDP6_INC_STATS_BH(net, field, is_udplite) do { \
if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\
else SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field); \
} while(0)
#define UDP6_INC_STATS_USER(net, field, __lite) do { \
if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field); \
else SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field); \
} while(0)
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
#define UDPX_INC_STATS_BH(sk, field) \
do { \
if ((sk)->sk_family == AF_INET) \
UDP_INC_STATS_BH(sock_net(sk), field, 0); \
else \
UDP6_INC_STATS_BH(sock_net(sk), field, 0); \
} while (0);
#else
#define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(sock_net(sk), field, 0)
#endif
/* /proc */
struct udp_seq_afinfo {
char *name;
sa_family_t family;
struct udp_table *udp_table;
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
extern int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo);
extern void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo);
extern int udp4_proc_init(void);
extern void udp4_proc_exit(void);
#endif
extern void udp_init(void);
extern int udp4_ufo_send_check(struct sk_buff *skb);
extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features);
#endif /* _UDP_H */
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