Commit 6579f5ba authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

raw: use net_hash_mix() in hash function 



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: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 42186e6c

include/net/raw.h

+11 −2
Original line number Diff line number Diff line
@@ -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;

net/ipv4/raw.c

+7 −6
Original line number Diff line number Diff line
@@ -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();

net/ipv6/raw.c

+2 −2
Original line number Diff line number Diff line
@@ -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) {