linux/include/net/inet_timewait_sock.h
Kuniyuki Iwashima 936a192f97 tcp: Add TIME_WAIT sockets in bhash2.
Jiri Slaby reported regression of bind() with a simple repro. [0]

The repro creates a TIME_WAIT socket and tries to bind() a new socket
with the same local address and port.  Before commit 28044fc1d4 ("net:
Add a bhash2 table hashed by port and address"), the bind() failed with
-EADDRINUSE, but now it succeeds.

The cited commit should have put TIME_WAIT sockets into bhash2; otherwise,
inet_bhash2_conflict() misses TIME_WAIT sockets when validating bind()
requests if the address is not a wildcard one.

The straight option is to move sk_bind2_node from struct sock to struct
sock_common to add twsk to bhash2 as implemented as RFC. [1]  However, the
binary layout change in the struct sock could affect performances moving
hot fields on different cachelines.

To avoid that, we add another TIME_WAIT list in inet_bind2_bucket and check
it while validating bind().

[0]: https://lore.kernel.org/netdev/6b971a4e-c7d8-411e-1f92-fda29b5b2fb9@kernel.org/
[1]: https://lore.kernel.org/netdev/20221221151258.25748-2-kuniyu@amazon.com/

Fixes: 28044fc1d4 ("net: Add a bhash2 table hashed by port and address")
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-12-30 07:25:52 +00:00

131 lines
3.8 KiB
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.
*
* Definitions for a generic INET TIMEWAIT sock
*
* From code originally in net/tcp.h
*/
#ifndef _INET_TIMEWAIT_SOCK_
#define _INET_TIMEWAIT_SOCK_
#include <linux/list.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <net/inet_sock.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/timewait_sock.h>
#include <linux/atomic.h>
struct inet_bind_bucket;
/*
* This is a TIME_WAIT sock. It works around the memory consumption
* problems of sockets in such a state on heavily loaded servers, but
* without violating the protocol specification.
*/
struct inet_timewait_sock {
/*
* Now struct sock also uses sock_common, so please just
* don't add nothing before this first member (__tw_common) --acme
*/
struct sock_common __tw_common;
#define tw_family __tw_common.skc_family
#define tw_state __tw_common.skc_state
#define tw_reuse __tw_common.skc_reuse
#define tw_reuseport __tw_common.skc_reuseport
#define tw_ipv6only __tw_common.skc_ipv6only
#define tw_bound_dev_if __tw_common.skc_bound_dev_if
#define tw_node __tw_common.skc_nulls_node
#define tw_bind_node __tw_common.skc_bind_node
#define tw_refcnt __tw_common.skc_refcnt
#define tw_hash __tw_common.skc_hash
#define tw_prot __tw_common.skc_prot
#define tw_net __tw_common.skc_net
#define tw_daddr __tw_common.skc_daddr
#define tw_v6_daddr __tw_common.skc_v6_daddr
#define tw_rcv_saddr __tw_common.skc_rcv_saddr
#define tw_v6_rcv_saddr __tw_common.skc_v6_rcv_saddr
#define tw_dport __tw_common.skc_dport
#define tw_num __tw_common.skc_num
#define tw_cookie __tw_common.skc_cookie
#define tw_dr __tw_common.skc_tw_dr
__u32 tw_mark;
volatile unsigned char tw_substate;
unsigned char tw_rcv_wscale;
/* Socket demultiplex comparisons on incoming packets. */
/* these three are in inet_sock */
__be16 tw_sport;
/* And these are ours. */
unsigned int tw_transparent : 1,
tw_flowlabel : 20,
tw_pad : 3, /* 3 bits hole */
tw_tos : 8;
u32 tw_txhash;
u32 tw_priority;
struct timer_list tw_timer;
struct inet_bind_bucket *tw_tb;
struct inet_bind2_bucket *tw_tb2;
struct hlist_node tw_bind2_node;
};
#define tw_tclass tw_tos
#define twsk_for_each_bound_bhash2(__tw, list) \
hlist_for_each_entry(__tw, list, tw_bind2_node)
static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
{
return (struct inet_timewait_sock *)sk;
}
void inet_twsk_free(struct inet_timewait_sock *tw);
void inet_twsk_put(struct inet_timewait_sock *tw);
void inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
struct inet_hashinfo *hashinfo);
struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
struct inet_timewait_death_row *dr,
const int state);
void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
struct inet_hashinfo *hashinfo);
void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo,
bool rearm);
static inline void inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo)
{
__inet_twsk_schedule(tw, timeo, false);
}
static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo)
{
__inet_twsk_schedule(tw, timeo, true);
}
void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
static inline
struct net *twsk_net(const struct inet_timewait_sock *twsk)
{
return read_pnet(&twsk->tw_net);
}
static inline
void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
{
write_pnet(&twsk->tw_net, net);
}
#endif /* _INET_TIMEWAIT_SOCK_ */