/*
 *      Linux INET6 implementation 
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>     
 *
 *      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 _IP6_FIB_H
#define _IP6_FIB_H

#include <linux/ipv6_route.h>
#include <linux/rtnetlink.h>
#include <linux/spinlock.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/netlink.h>
#include <net/inetpeer.h>

#ifdef CONFIG_IPV6_MULTIPLE_TABLES
#define FIB6_TABLE_HASHSZ 256
#else
#define FIB6_TABLE_HASHSZ 1
#endif

struct rt6_info;

struct fib6_config {
        u32             fc_table;
        u32             fc_metric;
        int             fc_dst_len;
        int             fc_src_len;
        int             fc_ifindex;
        u32             fc_flags;
        u32             fc_protocol;
        u32             fc_type;        /* only 8 bits are used */

        struct in6_addr fc_dst;
        struct in6_addr fc_src;
        struct in6_addr fc_prefsrc;
        struct in6_addr fc_gateway;

        unsigned long   fc_expires;
        struct nlattr   *fc_mx;
        int             fc_mx_len;
        int             fc_mp_len;
        struct nlattr   *fc_mp;

        struct nl_info  fc_nlinfo;
        struct nlattr   *fc_encap;
        u16             fc_encap_type;
};

struct fib6_node {
        struct fib6_node        *parent;
        struct fib6_node        *left;
        struct fib6_node        *right;
#ifdef CONFIG_IPV6_SUBTREES
        struct fib6_node        *subtree;
#endif
        struct rt6_info         *leaf;

        __u16                   fn_bit;         /* bit key */
        __u16                   fn_flags;
        int                     fn_sernum;
        struct rt6_info         *rr_ptr;
};

#ifndef CONFIG_IPV6_SUBTREES
#define FIB6_SUBTREE(fn)        NULL
#else
#define FIB6_SUBTREE(fn)        ((fn)->subtree)
#endif

struct mx6_config {
        const u32 *mx;
        DECLARE_BITMAP(mx_valid, RTAX_MAX);
};

/*
 *      routing information
 *
 */

struct rt6key {
        struct in6_addr addr;
        int             plen;
};

struct fib6_table;

struct rt6_info {
        struct dst_entry                dst;

        /*
         * Tail elements of dst_entry (__refcnt etc.)
         * and these elements (rarely used in hot path) are in
         * the same cache line.
         */
        struct fib6_table               *rt6i_table;
        struct fib6_node                *rt6i_node;

        struct in6_addr                 rt6i_gateway;

        /* Multipath routes:
         * siblings is a list of rt6_info that have the the same metric/weight,
         * destination, but not the same gateway. nsiblings is just a cache
         * to speed up lookup.
         */
        struct list_head                rt6i_siblings;
        unsigned int                    rt6i_nsiblings;

        atomic_t                        rt6i_ref;

        /* These are in a separate cache line. */
        struct rt6key                   rt6i_dst ____cacheline_aligned_in_smp;
        u32                             rt6i_flags;
        struct rt6key                   rt6i_src;
        struct rt6key                   rt6i_prefsrc;

        struct list_head                rt6i_uncached;
        struct uncached_list            *rt6i_uncached_list;

        struct inet6_dev                *rt6i_idev;
        struct rt6_info * __percpu      *rt6i_pcpu;

        u32                             rt6i_metric;
        u32                             rt6i_pmtu;
        /* more non-fragment space at head required */
        unsigned short                  rt6i_nfheader_len;
        u8                              rt6i_protocol;
};

static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
{
        return ((struct rt6_info *)dst)->rt6i_idev;
}

static inline void rt6_clean_expires(struct rt6_info *rt)
{
        rt->rt6i_flags &= ~RTF_EXPIRES;
        rt->dst.expires = 0;
}

static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)
{
        rt->dst.expires = expires;
        rt->rt6i_flags |= RTF_EXPIRES;
}

static inline void rt6_update_expires(struct rt6_info *rt0, int timeout)
{
        struct rt6_info *rt;

        for (rt = rt0; rt && !(rt->rt6i_flags & RTF_EXPIRES);
             rt = (struct rt6_info *)rt->dst.from);
        if (rt && rt != rt0)
                rt0->dst.expires = rt->dst.expires;

        dst_set_expires(&rt0->dst, timeout);
        rt0->rt6i_flags |= RTF_EXPIRES;
}

static inline u32 rt6_get_cookie(const struct rt6_info *rt)
{
        if (rt->rt6i_flags & RTF_PCPU ||
            (unlikely(rt->dst.flags & DST_NOCACHE) && rt->dst.from))
                rt = (struct rt6_info *)(rt->dst.from);

        return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
}

static inline void ip6_rt_put(struct rt6_info *rt)
{
        /* dst_release() accepts a NULL parameter.
         * We rely on dst being first structure in struct rt6_info
         */
        BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
        dst_release(&rt->dst);
}

enum fib6_walk_state {
#ifdef CONFIG_IPV6_SUBTREES
        FWS_S,
#endif
        FWS_L,
        FWS_R,
        FWS_C,
        FWS_U
};

struct fib6_walker {
        struct list_head lh;
        struct fib6_node *root, *node;
        struct rt6_info *leaf;
        enum fib6_walk_state state;
        bool prune;
        unsigned int skip;
        unsigned int count;
        int (*func)(struct fib6_walker *);
        void *args;
};

struct rt6_statistics {
        __u32           fib_nodes;
        __u32           fib_route_nodes;
        __u32           fib_rt_alloc;           /* permanent routes     */
        __u32           fib_rt_entries;         /* rt entries in table  */
        __u32           fib_rt_cache;           /* cache routes         */
        __u32           fib_discarded_routes;
};

#define RTN_TL_ROOT     0x0001
#define RTN_ROOT        0x0002          /* tree root node               */
#define RTN_RTINFO      0x0004          /* node with valid routing info */

/*
 *      priority levels (or metrics)
 *
 */


struct fib6_table {
        struct hlist_node       tb6_hlist;
        u32                     tb6_id;
        rwlock_t                tb6_lock;
        struct fib6_node        tb6_root;
        struct inet_peer_base   tb6_peers;
        unsigned int            flags;
#define RT6_TABLE_HAS_DFLT_ROUTER       BIT(0)
};

#define RT6_TABLE_UNSPEC        RT_TABLE_UNSPEC
#define RT6_TABLE_MAIN          RT_TABLE_MAIN
#define RT6_TABLE_DFLT          RT6_TABLE_MAIN
#define RT6_TABLE_INFO          RT6_TABLE_MAIN
#define RT6_TABLE_PREFIX        RT6_TABLE_MAIN

#ifdef CONFIG_IPV6_MULTIPLE_TABLES
#define FIB6_TABLE_MIN          1
#define FIB6_TABLE_MAX          RT_TABLE_MAX
#define RT6_TABLE_LOCAL         RT_TABLE_LOCAL
#else
#define FIB6_TABLE_MIN          RT_TABLE_MAIN
#define FIB6_TABLE_MAX          FIB6_TABLE_MIN
#define RT6_TABLE_LOCAL         RT6_TABLE_MAIN
#endif

typedef struct rt6_info *(*pol_lookup_t)(struct net *,
                                         struct fib6_table *,
                                         struct flowi6 *, int);

/*
 *      exported functions
 */

struct fib6_table *fib6_get_table(struct net *net, u32 id);
struct fib6_table *fib6_new_table(struct net *net, u32 id);
struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
                                   int flags, pol_lookup_t lookup);

struct fib6_node *fib6_lookup(struct fib6_node *root,
                              const struct in6_addr *daddr,
                              const struct in6_addr *saddr);

struct fib6_node *fib6_locate(struct fib6_node *root,
                              const struct in6_addr *daddr, int dst_len,
                              const struct in6_addr *saddr, int src_len);

void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
                    void *arg);

int fib6_add(struct fib6_node *root, struct rt6_info *rt,
             struct nl_info *info, struct mx6_config *mxc);
int fib6_del(struct rt6_info *rt, struct nl_info *info);

void inet6_rt_notify(int event, struct rt6_info *rt, struct nl_info *info,
                     unsigned int flags);

void fib6_run_gc(unsigned long expires, struct net *net, bool force);

void fib6_gc_cleanup(void);

int fib6_init(void);

int ipv6_route_open(struct inode *inode, struct file *file);

#ifdef CONFIG_IPV6_MULTIPLE_TABLES
int fib6_rules_init(void);
void fib6_rules_cleanup(void);
#else
static inline int               fib6_rules_init(void)
{
        return 0;
}
static inline void              fib6_rules_cleanup(void)
{
        return ;
}
#endif
#endif