include/net/neighbour.h

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This source file includes following definitions.
neigh_var_set
neigh_parms_data_state_setall
neigh_parms_data_state_cleanall
neigh_parms_family
neighbour_priv
neigh_create
neigh_parms_net
pneigh_net
__neigh_parms_put
neigh_parms_clone
neigh_release
neigh_clone
neigh_event_send
neigh_hh_bridge
neigh_hh_output
__neigh_lookup
__neigh_lookup_errno
neigh_ha_snapshot
#ifndef _NET_NEIGHBOUR_H
#define _NET_NEIGHBOUR_H

#include <linux/neighbour.h>

/*
 *      Generic neighbour manipulation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
 *
 *      Changes:
 *
 *      Harald Welte:           <laforge@gnumonks.org>
 *              - Add neighbour cache statistics like rtstat
 */

#include <linux/atomic.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/rcupdate.h>
#include <linux/seq_file.h>
#include <linux/bitmap.h>

#include <linux/err.h>
#include <linux/sysctl.h>
#include <linux/workqueue.h>
#include <net/rtnetlink.h>

/*
 * NUD stands for "neighbor unreachability detection"
 */

#define NUD_IN_TIMER    (NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
#define NUD_VALID       (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
#define NUD_CONNECTED   (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)

struct neighbour;

enum {
        NEIGH_VAR_MCAST_PROBES,
        NEIGH_VAR_UCAST_PROBES,
        NEIGH_VAR_APP_PROBES,
        NEIGH_VAR_RETRANS_TIME,
        NEIGH_VAR_BASE_REACHABLE_TIME,
        NEIGH_VAR_DELAY_PROBE_TIME,
        NEIGH_VAR_GC_STALETIME,
        NEIGH_VAR_QUEUE_LEN_BYTES,
        NEIGH_VAR_PROXY_QLEN,
        NEIGH_VAR_ANYCAST_DELAY,
        NEIGH_VAR_PROXY_DELAY,
        NEIGH_VAR_LOCKTIME,
#define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
        /* Following are used as a second way to access one of the above */
        NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
        NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
        NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
        /* Following are used by "default" only */
        NEIGH_VAR_GC_INTERVAL,
        NEIGH_VAR_GC_THRESH1,
        NEIGH_VAR_GC_THRESH2,
        NEIGH_VAR_GC_THRESH3,
        NEIGH_VAR_MAX
};

struct neigh_parms {
#ifdef CONFIG_NET_NS
        struct net *net;
#endif
        struct net_device *dev;
        struct neigh_parms *next;
        int     (*neigh_setup)(struct neighbour *);
        void    (*neigh_cleanup)(struct neighbour *);
        struct neigh_table *tbl;

        void    *sysctl_table;

        int dead;
        atomic_t refcnt;
        struct rcu_head rcu_head;

        int     reachable_time;
        int     data[NEIGH_VAR_DATA_MAX];
        DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
};

static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
{
        set_bit(index, p->data_state);
        p->data[index] = val;
}

#define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])

/* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
 * In other cases, NEIGH_VAR_SET should be used.
 */
#define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
#define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)

static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
{
        bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
}

static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
{
        bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
}

struct neigh_statistics {
        unsigned long allocs;           /* number of allocated neighs */
        unsigned long destroys;         /* number of destroyed neighs */
        unsigned long hash_grows;       /* number of hash resizes */

        unsigned long res_failed;       /* number of failed resolutions */

        unsigned long lookups;          /* number of lookups */
        unsigned long hits;             /* number of hits (among lookups) */

        unsigned long rcv_probes_mcast; /* number of received mcast ipv6 */
        unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */

        unsigned long periodic_gc_runs; /* number of periodic GC runs */
        unsigned long forced_gc_runs;   /* number of forced GC runs */

        unsigned long unres_discards;   /* number of unresolved drops */
};

#define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)

struct neighbour {
        struct neighbour __rcu  *next;
        struct neigh_table      *tbl;
        struct neigh_parms      *parms;
        unsigned long           confirmed;
        unsigned long           updated;
        rwlock_t                lock;
        atomic_t                refcnt;
        struct sk_buff_head     arp_queue;
        unsigned int            arp_queue_len_bytes;
        struct timer_list       timer;
        unsigned long           used;
        atomic_t                probes;
        __u8                    flags;
        __u8                    nud_state;
        __u8                    type;
        __u8                    dead;
        seqlock_t               ha_lock;
        unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
        struct hh_cache         hh;
        int                     (*output)(struct neighbour *, struct sk_buff *);
        const struct neigh_ops  *ops;
        struct rcu_head         rcu;
        struct net_device       *dev;
        u8                      primary_key[0];
};

struct neigh_ops {
        int                     family;
        void                    (*solicit)(struct neighbour *, struct sk_buff *);
        void                    (*error_report)(struct neighbour *, struct sk_buff *);
        int                     (*output)(struct neighbour *, struct sk_buff *);
        int                     (*connected_output)(struct neighbour *, struct sk_buff *);
};

struct pneigh_entry {
        struct pneigh_entry     *next;
#ifdef CONFIG_NET_NS
        struct net              *net;
#endif
        struct net_device       *dev;
        u8                      flags;
        u8                      key[0];
};

/*
 *      neighbour table manipulation
 */

#define NEIGH_NUM_HASH_RND      4

struct neigh_hash_table {
        struct neighbour __rcu  **hash_buckets;
        unsigned int            hash_shift;
        __u32                   hash_rnd[NEIGH_NUM_HASH_RND];
        struct rcu_head         rcu;
};


struct neigh_table {
        struct neigh_table      *next;
        int                     family;
        int                     entry_size;
        int                     key_len;
        __u32                   (*hash)(const void *pkey,
                                        const struct net_device *dev,
                                        __u32 *hash_rnd);
        int                     (*constructor)(struct neighbour *);
        int                     (*pconstructor)(struct pneigh_entry *);
        void                    (*pdestructor)(struct pneigh_entry *);
        void                    (*proxy_redo)(struct sk_buff *skb);
        char                    *id;
        struct neigh_parms      parms;
        int                     gc_interval;
        int                     gc_thresh1;
        int                     gc_thresh2;
        int                     gc_thresh3;
        unsigned long           last_flush;
        struct delayed_work     gc_work;
        struct timer_list       proxy_timer;
        struct sk_buff_head     proxy_queue;
        atomic_t                entries;
        rwlock_t                lock;
        unsigned long           last_rand;
        struct neigh_statistics __percpu *stats;
        struct neigh_hash_table __rcu *nht;
        struct pneigh_entry     **phash_buckets;
};

static inline int neigh_parms_family(struct neigh_parms *p)
{
        return p->tbl->family;
}

#define NEIGH_PRIV_ALIGN        sizeof(long long)
#define NEIGH_ENTRY_SIZE(size)  ALIGN((size), NEIGH_PRIV_ALIGN)

static inline void *neighbour_priv(const struct neighbour *n)
{
        return (char *)n + n->tbl->entry_size;
}

/* flags for neigh_update() */
#define NEIGH_UPDATE_F_OVERRIDE                 0x00000001
#define NEIGH_UPDATE_F_WEAK_OVERRIDE            0x00000002
#define NEIGH_UPDATE_F_OVERRIDE_ISROUTER        0x00000004
#define NEIGH_UPDATE_F_ISROUTER                 0x40000000
#define NEIGH_UPDATE_F_ADMIN                    0x80000000

void neigh_table_init(struct neigh_table *tbl);
int neigh_table_clear(struct neigh_table *tbl);
struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
                               struct net_device *dev);
struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
                                     const void *pkey);
struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
                                 struct net_device *dev, bool want_ref);
static inline struct neighbour *neigh_create(struct neigh_table *tbl,
                                             const void *pkey,
                                             struct net_device *dev)
{
        return __neigh_create(tbl, pkey, dev, true);
}
void neigh_destroy(struct neighbour *neigh);
int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
void __neigh_set_probe_once(struct neighbour *neigh);
void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
int neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
struct neighbour *neigh_event_ns(struct neigh_table *tbl,
                                                u8 *lladdr, void *saddr,
                                                struct net_device *dev);

struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
                                      struct neigh_table *tbl);
void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);

static inline
struct net *neigh_parms_net(const struct neigh_parms *parms)
{
        return read_pnet(&parms->net);
}

unsigned long neigh_rand_reach_time(unsigned long base);

void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
                    struct sk_buff *skb);
struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
                                   const void *key, struct net_device *dev,
                                   int creat);
struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
                                     const void *key, struct net_device *dev);
int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
                  struct net_device *dev);

static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
{
        return read_pnet(&pneigh->net);
}

void neigh_app_ns(struct neighbour *n);
void neigh_for_each(struct neigh_table *tbl,
                    void (*cb)(struct neighbour *, void *), void *cookie);
void __neigh_for_each_release(struct neigh_table *tbl,
                              int (*cb)(struct neighbour *));
void pneigh_for_each(struct neigh_table *tbl,
                     void (*cb)(struct pneigh_entry *));

struct neigh_seq_state {
        struct seq_net_private p;
        struct neigh_table *tbl;
        struct neigh_hash_table *nht;
        void *(*neigh_sub_iter)(struct neigh_seq_state *state,
                                struct neighbour *n, loff_t *pos);
        unsigned int bucket;
        unsigned int flags;
#define NEIGH_SEQ_NEIGH_ONLY    0x00000001
#define NEIGH_SEQ_IS_PNEIGH     0x00000002
#define NEIGH_SEQ_SKIP_NOARP    0x00000004
};
void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
                      unsigned int);
void *neigh_seq_next(struct seq_file *, void *, loff_t *);
void neigh_seq_stop(struct seq_file *, void *);

int neigh_proc_dointvec(struct ctl_table *ctl, int write,
                        void __user *buffer, size_t *lenp, loff_t *ppos);
int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
                                void __user *buffer,
                                size_t *lenp, loff_t *ppos);
int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
                                   void __user *buffer,
                                   size_t *lenp, loff_t *ppos);

int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
                          proc_handler *proc_handler);
void neigh_sysctl_unregister(struct neigh_parms *p);

static inline void __neigh_parms_put(struct neigh_parms *parms)
{
        atomic_dec(&parms->refcnt);
}

static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
{
        atomic_inc(&parms->refcnt);
        return parms;
}

/*
 *      Neighbour references
 */

static inline void neigh_release(struct neighbour *neigh)
{
        if (atomic_dec_and_test(&neigh->refcnt))
                neigh_destroy(neigh);
}

static inline struct neighbour * neigh_clone(struct neighbour *neigh)
{
        if (neigh)
                atomic_inc(&neigh->refcnt);
        return neigh;
}

#define neigh_hold(n)   atomic_inc(&(n)->refcnt)

static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
{
        unsigned long now = jiffies;
        
        if (neigh->used != now)
                neigh->used = now;
        if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
                return __neigh_event_send(neigh, skb);
        return 0;
}

#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
{
        unsigned int seq, hh_alen;

        do {
                seq = read_seqbegin(&hh->hh_lock);
                hh_alen = HH_DATA_ALIGN(ETH_HLEN);
                memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
        } while (read_seqretry(&hh->hh_lock, seq));
        return 0;
}
#endif

static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
{
        unsigned int seq;
        int hh_len;

        do {
                seq = read_seqbegin(&hh->hh_lock);
                hh_len = hh->hh_len;
                if (likely(hh_len <= HH_DATA_MOD)) {
                        /* this is inlined by gcc */
                        memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
                } else {
                        int hh_alen = HH_DATA_ALIGN(hh_len);

                        memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
                }
        } while (read_seqretry(&hh->hh_lock, seq));

        skb_push(skb, hh_len);
        return dev_queue_xmit(skb);
}

static inline struct neighbour *
__neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
{
        struct neighbour *n = neigh_lookup(tbl, pkey, dev);

        if (n || !creat)
                return n;

        n = neigh_create(tbl, pkey, dev);
        return IS_ERR(n) ? NULL : n;
}

static inline struct neighbour *
__neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
  struct net_device *dev)
{
        struct neighbour *n = neigh_lookup(tbl, pkey, dev);

        if (n)
                return n;

        return neigh_create(tbl, pkey, dev);
}

struct neighbour_cb {
        unsigned long sched_next;
        unsigned int flags;
};

#define LOCALLY_ENQUEUED 0x1

#define NEIGH_CB(skb)   ((struct neighbour_cb *)(skb)->cb)

static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
                                     const struct net_device *dev)
{
        unsigned int seq;

        do {
                seq = read_seqbegin(&n->ha_lock);
                memcpy(dst, n->ha, dev->addr_len);
        } while (read_seqretry(&n->ha_lock, seq));
}
#endif
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root/include/net/neighbour.h

INCLUDED FROM

DEFINITIONS
