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raw: use net_hash_mix() in hash function

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Some applications seem to rely on RAW sockets.

If they use private netns, we can avoid piling all RAW
sockets bound to a given protocol into a single bucket.

Also place (struct raw_hashinfo).lock into its own
cache line to limit false sharing.

Alternative would be to have per-netns hashtables,
but this seems too expensive for most netns
where RAW sockets are not used.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2023-02-02 09:41:00 +00:00 committed by Jakub Kicinski
parent 42186e6c00
commit 6579f5bacc
3 changed files with 20 additions and 10 deletions
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13
include/net/raw.h
View file

@ -15,6 +15,8 @@
#include <net/inet_sock.h>
#include <net/protocol.h>
#include <net/netns/hash.h>
#include <linux/hash.h>
#include <linux/icmp.h>
extern struct proto raw_prot;
@ -29,13 +31,20 @@ int raw_local_deliver(struct sk_buff *, int);
int raw_rcv(struct sock *, struct sk_buff *);
#define RAW_HTABLE_SIZE MAX_INET_PROTOS
#define RAW_HTABLE_LOG 8
#define RAW_HTABLE_SIZE (1U << RAW_HTABLE_LOG)
struct raw_hashinfo {
spinlock_t lock;
struct hlist_nulls_head ht[RAW_HTABLE_SIZE];
struct hlist_nulls_head ht[RAW_HTABLE_SIZE] ____cacheline_aligned;
};
static inline u32 raw_hashfunc(const struct net *net, u32 proto)
{
return hash_32(net_hash_mix(net) ^ proto, RAW_HTABLE_LOG);
}
static inline void raw_hashinfo_init(struct raw_hashinfo *hashinfo)
{
int i;

13
net/ipv4/raw.c
View file

@ -93,7 +93,7 @@ int raw_hash_sk(struct sock *sk)
struct raw_hashinfo *h = sk->sk_prot->h.raw_hash;
struct hlist_nulls_head *hlist;
hlist = &h->ht[inet_sk(sk)->inet_num & (RAW_HTABLE_SIZE - 1)];
hlist = &h->ht[raw_hashfunc(sock_net(sk), inet_sk(sk)->inet_num)];
spin_lock(&h->lock);
__sk_nulls_add_node_rcu(sk, hlist);
@ -160,9 +160,9 @@ static int icmp_filter(const struct sock *sk, const struct sk_buff *skb)
* RFC 1122: SHOULD pass TOS value up to the transport layer.
* -> It does. And not only TOS, but all IP header.
*/
static int raw_v4_input(struct sk_buff *skb, const struct iphdr *iph, int hash)
static int raw_v4_input(struct net *net, struct sk_buff *skb,
const struct iphdr *iph, int hash)
{
struct net *net = dev_net(skb->dev);
struct hlist_nulls_head *hlist;
struct hlist_nulls_node *hnode;
int sdif = inet_sdif(skb);
@ -193,9 +193,10 @@ static int raw_v4_input(struct sk_buff *skb, const struct iphdr *iph, int hash)
int raw_local_deliver(struct sk_buff *skb, int protocol)
{
int hash = protocol & (RAW_HTABLE_SIZE - 1);
struct net *net = dev_net(skb->dev);
return raw_v4_input(skb, ip_hdr(skb), hash);
return raw_v4_input(net, skb, ip_hdr(skb),
raw_hashfunc(net, protocol));
}
static void raw_err(struct sock *sk, struct sk_buff *skb, u32 info)
@ -271,7 +272,7 @@ void raw_icmp_error(struct sk_buff *skb, int protocol, u32 info)
struct sock *sk;
int hash;
hash = protocol & (RAW_HTABLE_SIZE - 1);
hash = raw_hashfunc(net, protocol);
hlist = &raw_v4_hashinfo.ht[hash];
rcu_read_lock();

4
net/ipv6/raw.c
View file

@ -152,7 +152,7 @@ static bool ipv6_raw_deliver(struct sk_buff *skb, int nexthdr)
saddr = &ipv6_hdr(skb)->saddr;
daddr = saddr + 1;
hash = nexthdr & (RAW_HTABLE_SIZE - 1);
hash = raw_hashfunc(net, nexthdr);
hlist = &raw_v6_hashinfo.ht[hash];
rcu_read_lock();
sk_nulls_for_each(sk, hnode, hlist) {
@ -338,7 +338,7 @@ void raw6_icmp_error(struct sk_buff *skb, int nexthdr,
struct sock *sk;
int hash;
hash = nexthdr & (RAW_HTABLE_SIZE - 1);
hash = raw_hashfunc(net, nexthdr);
hlist = &raw_v6_hashinfo.ht[hash];
rcu_read_lock();
sk_nulls_for_each(sk, hnode, hlist) {