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alistair23-linux/include/net/ip_fib.h
David S. Miller 21d8c49e01 ipv4: Call fib_select_default() only when actually necessary. 
fib_select_default() is a complete NOP, and completely pointless
to invoke, when we have no more than 1 default route installed.

And this is far and away the common case.

So remember how many prefixlen==0 routes we have in the routing
table, and elide the call when we have no more than one of those.

This cuts output route creation time by 157 cycles on Niagara2+.

In order to add the new int to fib_table, we have to correct the type
of ->tb_data[] to unsigned long, otherwise the private area will be
unaligned on 64-bit systems.

Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
2011-04-14 15:05:22 -07:00

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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 Forwarding Information Base.
*
* Authors: A.N.Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* 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 _NET_IP_FIB_H
#define _NET_IP_FIB_H
#include <net/flow.h>
#include <linux/seq_file.h>
#include <net/fib_rules.h>
struct fib_config {
u8 fc_dst_len;
u8 fc_tos;
u8 fc_protocol;
u8 fc_scope;
u8 fc_type;
/* 3 bytes unused */
u32 fc_table;
__be32 fc_dst;
__be32 fc_gw;
int fc_oif;
u32 fc_flags;
u32 fc_priority;
__be32 fc_prefsrc;
struct nlattr *fc_mx;
struct rtnexthop *fc_mp;
int fc_mx_len;
int fc_mp_len;
u32 fc_flow;
u32 fc_nlflags;
struct nl_info fc_nlinfo;
};
struct fib_info;
struct fib_nh {
struct net_device *nh_dev;
struct hlist_node nh_hash;
struct fib_info *nh_parent;
unsigned nh_flags;
unsigned char nh_scope;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int nh_weight;
int nh_power;
#endif
#ifdef CONFIG_IP_ROUTE_CLASSID
__u32 nh_tclassid;
#endif
int nh_oif;
__be32 nh_gw;
__be32 nh_saddr;
int nh_saddr_genid;
};
/*
* This structure contains data shared by many of routes.
*/
struct fib_info {
struct hlist_node fib_hash;
struct hlist_node fib_lhash;
struct net *fib_net;
int fib_treeref;
atomic_t fib_clntref;
unsigned fib_flags;
unsigned char fib_dead;
unsigned char fib_protocol;
unsigned char fib_scope;
__be32 fib_prefsrc;
u32 fib_priority;
u32 *fib_metrics;
#define fib_mtu fib_metrics[RTAX_MTU-1]
#define fib_window fib_metrics[RTAX_WINDOW-1]
#define fib_rtt fib_metrics[RTAX_RTT-1]
#define fib_advmss fib_metrics[RTAX_ADVMSS-1]
int fib_nhs;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int fib_power;
#endif
struct rcu_head rcu;
struct fib_nh fib_nh[0];
#define fib_dev fib_nh[0].nh_dev
};
#ifdef CONFIG_IP_MULTIPLE_TABLES
struct fib_rule;
#endif
struct fib_table;
struct fib_result {
unsigned char prefixlen;
unsigned char nh_sel;
unsigned char type;
unsigned char scope;
struct fib_info *fi;
struct fib_table *table;
struct list_head *fa_head;
#ifdef CONFIG_IP_MULTIPLE_TABLES
struct fib_rule *r;
#endif
};
struct fib_result_nl {
__be32 fl_addr; /* To be looked up*/
u32 fl_mark;
unsigned char fl_tos;
unsigned char fl_scope;
unsigned char tb_id_in;
unsigned char tb_id; /* Results */
unsigned char prefixlen;
unsigned char nh_sel;
unsigned char type;
unsigned char scope;
int err;
};
#ifdef CONFIG_IP_ROUTE_MULTIPATH
#define FIB_RES_NH(res) ((res).fi->fib_nh[(res).nh_sel])
#define FIB_TABLE_HASHSZ 2
#else /* CONFIG_IP_ROUTE_MULTIPATH */
#define FIB_RES_NH(res) ((res).fi->fib_nh[0])
#define FIB_TABLE_HASHSZ 256
#endif /* CONFIG_IP_ROUTE_MULTIPATH */
extern __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh);
#define FIB_RES_SADDR(net, res) \
((FIB_RES_NH(res).nh_saddr_genid == \
atomic_read(&(net)->ipv4.dev_addr_genid)) ? \
FIB_RES_NH(res).nh_saddr : \
fib_info_update_nh_saddr((net), &FIB_RES_NH(res)))
#define FIB_RES_GW(res) (FIB_RES_NH(res).nh_gw)
#define FIB_RES_DEV(res) (FIB_RES_NH(res).nh_dev)
#define FIB_RES_OIF(res) (FIB_RES_NH(res).nh_oif)
#define FIB_RES_PREFSRC(net, res) ((res).fi->fib_prefsrc ? : \
FIB_RES_SADDR(net, res))
struct fib_table {
struct hlist_node tb_hlist;
u32 tb_id;
int tb_default;
int tb_num_default;
unsigned long tb_data[0];
};
extern int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
struct fib_result *res, int fib_flags);
extern int fib_table_insert(struct fib_table *, struct fib_config *);
extern int fib_table_delete(struct fib_table *, struct fib_config *);
extern int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
struct netlink_callback *cb);
extern int fib_table_flush(struct fib_table *table);
extern void fib_free_table(struct fib_table *tb);
#ifndef CONFIG_IP_MULTIPLE_TABLES
#define TABLE_LOCAL_INDEX 0
#define TABLE_MAIN_INDEX 1
static inline struct fib_table *fib_get_table(struct net *net, u32 id)
{
struct hlist_head *ptr;
ptr = id == RT_TABLE_LOCAL ?
&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX] :
&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX];
return hlist_entry(ptr->first, struct fib_table, tb_hlist);
}
static inline struct fib_table *fib_new_table(struct net *net, u32 id)
{
return fib_get_table(net, id);
}
static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
struct fib_result *res)
{
struct fib_table *table;
table = fib_get_table(net, RT_TABLE_LOCAL);
if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))
return 0;
table = fib_get_table(net, RT_TABLE_MAIN);
if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))
return 0;
return -ENETUNREACH;
}
#else /* CONFIG_IP_MULTIPLE_TABLES */
extern int __net_init fib4_rules_init(struct net *net);
extern void __net_exit fib4_rules_exit(struct net *net);
#ifdef CONFIG_IP_ROUTE_CLASSID
extern u32 fib_rules_tclass(const struct fib_result *res);
#endif
extern int fib_lookup(struct net *n, struct flowi4 *flp, struct fib_result *res);
extern struct fib_table *fib_new_table(struct net *net, u32 id);
extern struct fib_table *fib_get_table(struct net *net, u32 id);
#endif /* CONFIG_IP_MULTIPLE_TABLES */
/* Exported by fib_frontend.c */
extern const struct nla_policy rtm_ipv4_policy[];
extern void ip_fib_init(void);
extern int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
u8 tos, int oif, struct net_device *dev,
__be32 *spec_dst, u32 *itag);
extern void fib_select_default(struct fib_result *res);
/* Exported by fib_semantics.c */
extern int ip_fib_check_default(__be32 gw, struct net_device *dev);
extern int fib_sync_down_dev(struct net_device *dev, int force);
extern int fib_sync_down_addr(struct net *net, __be32 local);
extern void fib_update_nh_saddrs(struct net_device *dev);
extern int fib_sync_up(struct net_device *dev);
extern void fib_select_multipath(struct fib_result *res);
/* Exported by fib_trie.c */
extern void fib_trie_init(void);
extern struct fib_table *fib_trie_table(u32 id);
static inline void fib_combine_itag(u32 *itag, const struct fib_result *res)
{
#ifdef CONFIG_IP_ROUTE_CLASSID
#ifdef CONFIG_IP_MULTIPLE_TABLES
u32 rtag;
#endif
*itag = FIB_RES_NH(*res).nh_tclassid<<16;
#ifdef CONFIG_IP_MULTIPLE_TABLES
rtag = fib_rules_tclass(res);
if (*itag == 0)
*itag = (rtag<<16);
*itag |= (rtag>>16);
#endif
#endif
}
extern void free_fib_info(struct fib_info *fi);
static inline void fib_info_put(struct fib_info *fi)
{
if (atomic_dec_and_test(&fi->fib_clntref))
free_fib_info(fi);
}
#ifdef CONFIG_PROC_FS
extern int __net_init fib_proc_init(struct net *net);
extern void __net_exit fib_proc_exit(struct net *net);
#else
static inline int fib_proc_init(struct net *net)
{
return 0;
}
static inline void fib_proc_exit(struct net *net)
{
}
#endif
#endif /* _NET_FIB_H */
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