b14f243a42
Eric noticed, that when there will be devices with equal indices, some hash functions that use them will become less effective as they could. Fix this in advance by mixing the net_device address into the hash value instead of the device index. This is true for arp and ndisc hash fns. The netlabel, can and llc ones are also ifindex-based, but that three are init_net-only, thus will not be affected. Many thanks to David and Eric for the hash32_ptr implementation! Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
/* linux/net/inet/arp.h */
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#ifndef _ARP_H
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#define _ARP_H
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#include <linux/if_arp.h>
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#include <linux/hash.h>
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#include <net/neighbour.h>
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extern struct neigh_table arp_tbl;
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static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd)
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{
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u32 val = key ^ hash32_ptr(dev);
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return val * hash_rnd;
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}
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static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key)
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{
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struct neigh_hash_table *nht = rcu_dereference_bh(arp_tbl.nht);
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struct neighbour *n;
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u32 hash_val;
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hash_val = arp_hashfn(key, dev, nht->hash_rnd[0]) >> (32 - nht->hash_shift);
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for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
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n != NULL;
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n = rcu_dereference_bh(n->next)) {
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if (n->dev == dev && *(u32 *)n->primary_key == key)
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return n;
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}
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return NULL;
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}
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static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key)
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{
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struct neighbour *n;
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rcu_read_lock_bh();
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n = __ipv4_neigh_lookup_noref(dev, key);
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if (n && !atomic_inc_not_zero(&n->refcnt))
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n = NULL;
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rcu_read_unlock_bh();
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return n;
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}
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extern void arp_init(void);
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extern int arp_find(unsigned char *haddr, struct sk_buff *skb);
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extern int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);
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extern void arp_send(int type, int ptype, __be32 dest_ip,
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struct net_device *dev, __be32 src_ip,
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const unsigned char *dest_hw,
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const unsigned char *src_hw, const unsigned char *th);
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extern int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir);
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extern void arp_ifdown(struct net_device *dev);
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extern struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
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struct net_device *dev, __be32 src_ip,
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const unsigned char *dest_hw,
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const unsigned char *src_hw,
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const unsigned char *target_hw);
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extern void arp_xmit(struct sk_buff *skb);
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int arp_invalidate(struct net_device *dev, __be32 ip);
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#endif /* _ARP_H */
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