path: root/net/ipv4/inet_hashtables.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Generic INET transport hashtables
 *
 * Authors:	Lotsa people, from code originally in tcp
 */

#include <linux/module.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/vmalloc.h>
#include <linux/memblock.h>

#include <net/addrconf.h>
#include <net/inet_connection_sock.h>
#include <net/inet_hashtables.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/inet6_hashtables.h>
#endif
#include <net/secure_seq.h>
#include <net/ip.h>
#include <net/tcp.h>
#include <net/sock_reuseport.h>

static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
			const __u16 lport, const __be32 faddr,
			const __be16 fport)
{
	static u32 inet_ehash_secret __read_mostly;

	net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));

	return __inet_ehashfn(laddr, lport, faddr, fport,
			      inet_ehash_secret + net_hash_mix(net));
}

/* This function handles inet_sock, but also timewait and request sockets
 * for IPv4/IPv6.
 */
static u32 sk_ehashfn(const struct sock *sk)
{
#if IS_ENABLED(CONFIG_IPV6)
	if (sk->sk_family == AF_INET6 &&
	    !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
		return inet6_ehashfn(sock_net(sk),
				     &sk->sk_v6_rcv_saddr, sk->sk_num,
				     &sk->sk_v6_daddr, sk->sk_dport);
#endif
	return inet_ehashfn(sock_net(sk),
			    sk->sk_rcv_saddr, sk->sk_num,
			    sk->sk_daddr, sk->sk_dport);
}

/*
 * Allocate and initialize a new local port bind bucket.
 * The bindhash mutex for snum's hash chain must be held here.
 */
struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
						 struct net *net,
						 struct inet_bind_hashbucket *head,
						 const unsigned short snum,
						 int l3mdev)
{
	struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);

	if (tb) {
		write_pnet(&tb->ib_net, net);
		tb->l3mdev    = l3mdev;
		tb->port      = snum;
		tb->fastreuse = 0;
		tb->fastreuseport = 0;
		INIT_HLIST_HEAD(&tb->owners);
		hlist_add_head(&tb->node, &head->chain);
	}
	return tb;
}

struct inet_bind2_bucket *inet_bind2_bucket_create(struct kmem_cache *cachep,
						   struct net *net,
						   struct inet_bind2_hashbucket *head,
						   const unsigned short port,
						   int l3mdev,
						   const struct sock *sk)
{
	struct inet_bind2_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);

	if (tb) {
		write_pnet(&tb->ib_net, net);
		tb->l3mdev    = l3mdev;
		tb->port      = port;
#if IS_ENABLED(CONFIG_IPV6)
		if (sk->sk_family == AF_INET6)
			tb->v6_rcv_saddr = sk->sk_v6_rcv_saddr;
		else
#endif
			tb->rcv_saddr = sk->sk_rcv_saddr;
		INIT_HLIST_HEAD(&tb->owners);
		hlist_add_head(&tb->node, &head->chain);
	}
	return tb;
}

static bool bind2_bucket_addr_match(struct inet_bind2_bucket *tb2, struct sock *sk)
{
#if IS_ENABLED(CONFIG_IPV6)
	if (sk->sk_family == AF_INET6)
		return ipv6_addr_equal(&tb2->v6_rcv_saddr,
				       &sk->sk_v6_rcv_saddr);
#endif
	return tb2->rcv_saddr == sk->sk_rcv_saddr;
}

/*
 * Caller must hold hashbucket lock for this tb with local BH disabled
 */
void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
{
	if (hlist_empty(&tb->owners)) {
		__hlist_del(&tb->node);
		kmem_cache_free(cachep, tb);
	}
}

/* Caller must hold the lock for the corresponding hashbucket in the bhash table
 * with local BH disabled
 */
void inet_bind2_bucket_destroy(struct kmem_cache *cachep, struct inet_bind2_bucket *tb)
{
	if (hlist_empty(&tb->owners)) {
		__hlist_del(&tb->node);
		kmem_cache_free(cachep, tb);
	}
}

void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
		    struct inet_bind2_bucket *tb2, const unsigned short snum)
{
	inet_sk(sk)->inet_num = snum;
	sk_add_bind_node(sk, &tb->owners);
	inet_csk(sk)->icsk_bind_hash = tb;
	sk_add_bind2_node(sk, &tb2->owners);
	inet_csk(sk)->icsk_bind2_hash = tb2;
}

/*
 * Get rid of any references to a local port held by the given sock.
 */
static void __inet_put_port(struct sock *sk)
{
	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
	const int bhash =