ip_fib.h

Go to the documentation of this file.

/*
 * 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, <[email protected]>
 *
 *      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 <linux/rcupdate.h>
#include <net/fib_rules.h>
#include <net/inetpeer.h>
#include <linux/percpu.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 rtable;

struct fib_nh_exception {
    struct fib_nh_exception __rcu   *fnhe_next;
    __be32              fnhe_daddr;
    u32             fnhe_pmtu;
    __be32              fnhe_gw;
    unsigned long           fnhe_expires;
    struct rtable __rcu     *fnhe_rth;
    unsigned long           fnhe_stamp;
};

struct fnhe_hash_bucket {
    struct fib_nh_exception __rcu   *chain;
};

#define FNHE_HASH_SIZE      2048
#define FNHE_RECLAIM_DEPTH  5

struct fib_nh {
    struct net_device   *nh_dev;
    struct hlist_node   nh_hash;
    struct fib_info     *nh_parent;
    unsigned int        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;
    struct rtable __rcu * __percpu *nh_pcpu_rth_output;
    struct rtable __rcu *nh_rth_input;
    struct fnhe_hash_bucket *nh_exceptions;
};

/*
 * 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 int        fib_flags;
    unsigned char       fib_dead;
    unsigned char       fib_protocol;
    unsigned char       fib_scope;
    unsigned char       fib_type;
    __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;
    u32     tclassid;
    struct fib_info *fi;
    struct fib_table *table;
    struct list_head *fa_head;
};

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);

extern struct fib_table *fib_new_table(struct net *net, u32 id);
extern struct fib_table *fib_get_table(struct net *net, u32 id);

extern int __fib_lookup(struct net *net, struct flowi4 *flp,
            struct fib_result *res);

static inline int fib_lookup(struct net *net, struct flowi4 *flp,
                 struct fib_result *res)
{
    if (!net->ipv4.fib_has_custom_rules) {
        res->tclassid = 0;
        if (net->ipv4.fib_local &&
            !fib_table_lookup(net->ipv4.fib_local, flp, res,
                      FIB_LOOKUP_NOREF))
            return 0;
        if (net->ipv4.fib_main &&
            !fib_table_lookup(net->ipv4.fib_main, flp, res,
                      FIB_LOOKUP_NOREF))
            return 0;
        if (net->ipv4.fib_default &&
            !fib_table_lookup(net->ipv4.fib_default, flp, res,
                      FIB_LOOKUP_NOREF))
            return 0;
        return -ENETUNREACH;
    }
    return __fib_lookup(net, flp, res);
}

#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 __be32 fib_compute_spec_dst(struct sk_buff *skb);
extern int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
                   u8 tos, int oif, struct net_device *dev,
                   struct in_device *idev, u32 *itag);
extern void fib_select_default(struct fib_result *res);
#ifdef CONFIG_IP_ROUTE_CLASSID
static inline int fib_num_tclassid_users(struct net *net)
{
    return net->ipv4.fib_num_tclassid_users;
}
#else
static inline int fib_num_tclassid_users(struct net *net)
{
    return 0;
}
#endif

/* 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 = res->tclassid;
    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 */