linux_dsm_epyc7002/net/ipv4/tcp_diag.c
Eric Dumazet 49d0900787 tcp: diag: Dont report negative values for rx queue
Both netlink and /proc/net/tcp interfaces can report transient
negative values for rx queue.

ss ->
State   Recv-Q Send-Q  Local Address:Port  Peer Address:Port
ESTAB   -6     6       127.0.0.1:45956     127.0.0.1:3333 

netstat ->
tcp   4294967290      6 127.0.0.1:37784  127.0.0.1:3333 ESTABLISHED

This is because we dont lock socket while computing 
tp->rcv_nxt - tp->copied_seq,
and another CPU can update copied_seq before rcv_next in RX path.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-03 16:06:13 -08:00

58 lines
1.5 KiB
C

/*
* tcp_diag.c Module for monitoring TCP transport protocols sockets.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/inet_diag.h>
#include <linux/tcp.h>
#include <net/tcp.h>
static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
void *_info)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct tcp_info *info = _info;
if (sk->sk_state == TCP_LISTEN) {
r->idiag_rqueue = sk->sk_ack_backlog;
r->idiag_wqueue = sk->sk_max_ack_backlog;
} else {
r->idiag_rqueue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
r->idiag_wqueue = tp->write_seq - tp->snd_una;
}
if (info != NULL)
tcp_get_info(sk, info);
}
static const struct inet_diag_handler tcp_diag_handler = {
.idiag_hashinfo = &tcp_hashinfo,
.idiag_get_info = tcp_diag_get_info,
.idiag_type = TCPDIAG_GETSOCK,
.idiag_info_size = sizeof(struct tcp_info),
};
static int __init tcp_diag_init(void)
{
return inet_diag_register(&tcp_diag_handler);
}
static void __exit tcp_diag_exit(void)
{
inet_diag_unregister(&tcp_diag_handler);
}
module_init(tcp_diag_init);
module_exit(tcp_diag_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_INET_DIAG, TCPDIAG_GETSOCK);