linux/include/net/ndisc.h
Pavel Emelyanov b14f243a42 net: Dont use ifindices in hash fns
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>
2012-08-09 16:18:06 -07:00

236 lines
5.9 KiB
C

#ifndef _NDISC_H
#define _NDISC_H
/*
* ICMP codes for neighbour discovery messages
*/
#define NDISC_ROUTER_SOLICITATION 133
#define NDISC_ROUTER_ADVERTISEMENT 134
#define NDISC_NEIGHBOUR_SOLICITATION 135
#define NDISC_NEIGHBOUR_ADVERTISEMENT 136
#define NDISC_REDIRECT 137
/*
* Router type: cross-layer information from link-layer to
* IPv6 layer reported by certain link types (e.g., RFC4214).
*/
#define NDISC_NODETYPE_UNSPEC 0 /* unspecified (default) */
#define NDISC_NODETYPE_HOST 1 /* host or unauthorized router */
#define NDISC_NODETYPE_NODEFAULT 2 /* non-default router */
#define NDISC_NODETYPE_DEFAULT 3 /* default router */
/*
* ndisc options
*/
enum {
__ND_OPT_PREFIX_INFO_END = 0,
ND_OPT_SOURCE_LL_ADDR = 1, /* RFC2461 */
ND_OPT_TARGET_LL_ADDR = 2, /* RFC2461 */
ND_OPT_PREFIX_INFO = 3, /* RFC2461 */
ND_OPT_REDIRECT_HDR = 4, /* RFC2461 */
ND_OPT_MTU = 5, /* RFC2461 */
__ND_OPT_ARRAY_MAX,
ND_OPT_ROUTE_INFO = 24, /* RFC4191 */
ND_OPT_RDNSS = 25, /* RFC5006 */
ND_OPT_DNSSL = 31, /* RFC6106 */
__ND_OPT_MAX
};
#define MAX_RTR_SOLICITATION_DELAY HZ
#define ND_REACHABLE_TIME (30*HZ)
#define ND_RETRANS_TIMER HZ
#include <linux/compiler.h>
#include <linux/icmpv6.h>
#include <linux/in6.h>
#include <linux/types.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/hash.h>
#include <net/neighbour.h>
struct ctl_table;
struct inet6_dev;
struct net_device;
struct net_proto_family;
struct sk_buff;
extern struct neigh_table nd_tbl;
struct nd_msg {
struct icmp6hdr icmph;
struct in6_addr target;
__u8 opt[0];
};
struct rs_msg {
struct icmp6hdr icmph;
__u8 opt[0];
};
struct ra_msg {
struct icmp6hdr icmph;
__be32 reachable_time;
__be32 retrans_timer;
};
struct nd_opt_hdr {
__u8 nd_opt_type;
__u8 nd_opt_len;
} __packed;
/* ND options */
struct ndisc_options {
struct nd_opt_hdr *nd_opt_array[__ND_OPT_ARRAY_MAX];
#ifdef CONFIG_IPV6_ROUTE_INFO
struct nd_opt_hdr *nd_opts_ri;
struct nd_opt_hdr *nd_opts_ri_end;
#endif
struct nd_opt_hdr *nd_useropts;
struct nd_opt_hdr *nd_useropts_end;
};
#define nd_opts_src_lladdr nd_opt_array[ND_OPT_SOURCE_LL_ADDR]
#define nd_opts_tgt_lladdr nd_opt_array[ND_OPT_TARGET_LL_ADDR]
#define nd_opts_pi nd_opt_array[ND_OPT_PREFIX_INFO]
#define nd_opts_pi_end nd_opt_array[__ND_OPT_PREFIX_INFO_END]
#define nd_opts_rh nd_opt_array[ND_OPT_REDIRECT_HDR]
#define nd_opts_mtu nd_opt_array[ND_OPT_MTU]
#define NDISC_OPT_SPACE(len) (((len)+2+7)&~7)
extern struct ndisc_options *ndisc_parse_options(u8 *opt, int opt_len,
struct ndisc_options *ndopts);
/*
* Return the padding between the option length and the start of the
* link addr. Currently only IP-over-InfiniBand needs this, although
* if RFC 3831 IPv6-over-Fibre Channel is ever implemented it may
* also need a pad of 2.
*/
static int ndisc_addr_option_pad(unsigned short type)
{
switch (type) {
case ARPHRD_INFINIBAND: return 2;
default: return 0;
}
}
static inline u8 *ndisc_opt_addr_data(struct nd_opt_hdr *p,
struct net_device *dev)
{
u8 *lladdr = (u8 *)(p + 1);
int lladdrlen = p->nd_opt_len << 3;
int prepad = ndisc_addr_option_pad(dev->type);
if (lladdrlen != NDISC_OPT_SPACE(dev->addr_len + prepad))
return NULL;
return lladdr + prepad;
}
static inline u32 ndisc_hashfn(const void *pkey, const struct net_device *dev, __u32 *hash_rnd)
{
const u32 *p32 = pkey;
return (((p32[0] ^ hash32_ptr(dev)) * hash_rnd[0]) +
(p32[1] * hash_rnd[1]) +
(p32[2] * hash_rnd[2]) +
(p32[3] * hash_rnd[3]));
}
static inline struct neighbour *__ipv6_neigh_lookup(struct neigh_table *tbl, struct net_device *dev, const void *pkey)
{
struct neigh_hash_table *nht;
const u32 *p32 = pkey;
struct neighbour *n;
u32 hash_val;
rcu_read_lock_bh();
nht = rcu_dereference_bh(tbl->nht);
hash_val = ndisc_hashfn(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
n != NULL;
n = rcu_dereference_bh(n->next)) {
u32 *n32 = (u32 *) n->primary_key;
if (n->dev == dev &&
((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
(n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0) {
if (!atomic_inc_not_zero(&n->refcnt))
n = NULL;
break;
}
}
rcu_read_unlock_bh();
return n;
}
extern int ndisc_init(void);
extern void ndisc_cleanup(void);
extern int ndisc_rcv(struct sk_buff *skb);
extern void ndisc_send_ns(struct net_device *dev,
struct neighbour *neigh,
const struct in6_addr *solicit,
const struct in6_addr *daddr,
const struct in6_addr *saddr);
extern void ndisc_send_rs(struct net_device *dev,
const struct in6_addr *saddr,
const struct in6_addr *daddr);
extern void ndisc_send_redirect(struct sk_buff *skb,
const struct in6_addr *target);
extern int ndisc_mc_map(const struct in6_addr *addr, char *buf,
struct net_device *dev, int dir);
extern struct sk_buff *ndisc_build_skb(struct net_device *dev,
const struct in6_addr *daddr,
const struct in6_addr *saddr,
struct icmp6hdr *icmp6h,
const struct in6_addr *target,
int llinfo);
extern void ndisc_send_skb(struct sk_buff *skb,
struct net_device *dev,
struct neighbour *neigh,
const struct in6_addr *daddr,
const struct in6_addr *saddr,
struct icmp6hdr *icmp6h);
/*
* IGMP
*/
extern int igmp6_init(void);
extern void igmp6_cleanup(void);
extern int igmp6_event_query(struct sk_buff *skb);
extern int igmp6_event_report(struct sk_buff *skb);
#ifdef CONFIG_SYSCTL
extern int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl,
int write,
void __user *buffer,
size_t *lenp,
loff_t *ppos);
int ndisc_ifinfo_sysctl_strategy(ctl_table *ctl,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen);
#endif
extern void inet6_ifinfo_notify(int event,
struct inet6_dev *idev);
#endif