linux/net/rds/tcp_connect.c
Tetsuo Handa 6997fbd7a3 net: rds: use maybe_get_net() when acquiring refcount on TCP sockets
Eric Dumazet is reporting addition on 0 problem at rds_tcp_tune(), for
delayed works queued in rds_wq might be invoked after a net namespace's
refcount already reached 0.

Since rds_tcp_exit_net() from cleanup_net() calls flush_workqueue(rds_wq),
it is guaranteed that we can instead use maybe_get_net() from delayed work
functions until rds_tcp_exit_net() returns.

Note that I'm not convinced that all works which might access a net
namespace are already queued in rds_wq by the moment rds_tcp_exit_net()
calls flush_workqueue(rds_wq). If some race is there, rds_tcp_exit_net()
will fail to wait for work functions, and kmem_cache_free() could be
called from net_free() before maybe_get_net() is called from
rds_tcp_tune().

Reported-by: Eric Dumazet <edumazet@google.com>
Fixes: 3a58f13a88 ("net: rds: acquire refcount on TCP sockets")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/41d09faf-bc78-1a87-dfd1-c6d1b5984b61@I-love.SAKURA.ne.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-05 16:44:49 -07:00

230 lines
6.2 KiB
C

/*
* Copyright (c) 2006, 2017 Oracle and/or its affiliates. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/kernel.h>
#include <linux/in.h>
#include <net/tcp.h>
#include "rds.h"
#include "tcp.h"
void rds_tcp_state_change(struct sock *sk)
{
void (*state_change)(struct sock *sk);
struct rds_conn_path *cp;
struct rds_tcp_connection *tc;
read_lock_bh(&sk->sk_callback_lock);
cp = sk->sk_user_data;
if (!cp) {
state_change = sk->sk_state_change;
goto out;
}
tc = cp->cp_transport_data;
state_change = tc->t_orig_state_change;
rdsdebug("sock %p state_change to %d\n", tc->t_sock, sk->sk_state);
switch (sk->sk_state) {
/* ignore connecting sockets as they make progress */
case TCP_SYN_SENT:
case TCP_SYN_RECV:
break;
case TCP_ESTABLISHED:
/* Force the peer to reconnect so that we have the
* TCP ports going from <smaller-ip>.<transient> to
* <larger-ip>.<RDS_TCP_PORT>. We avoid marking the
* RDS connection as RDS_CONN_UP until the reconnect,
* to avoid RDS datagram loss.
*/
if (rds_addr_cmp(&cp->cp_conn->c_laddr,
&cp->cp_conn->c_faddr) >= 0 &&
rds_conn_path_transition(cp, RDS_CONN_CONNECTING,
RDS_CONN_ERROR)) {
rds_conn_path_drop(cp, false);
} else {
rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
}
break;
case TCP_CLOSE_WAIT:
case TCP_CLOSE:
rds_conn_path_drop(cp, false);
break;
default:
break;
}
out:
read_unlock_bh(&sk->sk_callback_lock);
state_change(sk);
}
int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
{
struct socket *sock = NULL;
struct sockaddr_in6 sin6;
struct sockaddr_in sin;
struct sockaddr *addr;
int addrlen;
bool isv6;
int ret;
struct rds_connection *conn = cp->cp_conn;
struct rds_tcp_connection *tc = cp->cp_transport_data;
/* for multipath rds,we only trigger the connection after
* the handshake probe has determined the number of paths.
*/
if (cp->cp_index > 0 && cp->cp_conn->c_npaths < 2)
return -EAGAIN;
mutex_lock(&tc->t_conn_path_lock);
if (rds_conn_path_up(cp)) {
mutex_unlock(&tc->t_conn_path_lock);
return 0;
}
if (ipv6_addr_v4mapped(&conn->c_laddr)) {
ret = sock_create_kern(rds_conn_net(conn), PF_INET,
SOCK_STREAM, IPPROTO_TCP, &sock);
isv6 = false;
} else {
ret = sock_create_kern(rds_conn_net(conn), PF_INET6,
SOCK_STREAM, IPPROTO_TCP, &sock);
isv6 = true;
}
if (ret < 0)
goto out;
if (!rds_tcp_tune(sock)) {
ret = -EINVAL;
goto out;
}
if (isv6) {
sin6.sin6_family = AF_INET6;
sin6.sin6_addr = conn->c_laddr;
sin6.sin6_port = 0;
sin6.sin6_flowinfo = 0;
sin6.sin6_scope_id = conn->c_dev_if;
addr = (struct sockaddr *)&sin6;
addrlen = sizeof(sin6);
} else {
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = conn->c_laddr.s6_addr32[3];
sin.sin_port = 0;
addr = (struct sockaddr *)&sin;
addrlen = sizeof(sin);
}
ret = sock->ops->bind(sock, addr, addrlen);
if (ret) {
rdsdebug("bind failed with %d at address %pI6c\n",
ret, &conn->c_laddr);
goto out;
}
if (isv6) {
sin6.sin6_family = AF_INET6;
sin6.sin6_addr = conn->c_faddr;
sin6.sin6_port = htons(RDS_TCP_PORT);
sin6.sin6_flowinfo = 0;
sin6.sin6_scope_id = conn->c_dev_if;
addr = (struct sockaddr *)&sin6;
addrlen = sizeof(sin6);
} else {
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = conn->c_faddr.s6_addr32[3];
sin.sin_port = htons(RDS_TCP_PORT);
addr = (struct sockaddr *)&sin;
addrlen = sizeof(sin);
}
/*
* once we call connect() we can start getting callbacks and they
* own the socket
*/
rds_tcp_set_callbacks(sock, cp);
ret = sock->ops->connect(sock, addr, addrlen, O_NONBLOCK);
rdsdebug("connect to address %pI6c returned %d\n", &conn->c_faddr, ret);
if (ret == -EINPROGRESS)
ret = 0;
if (ret == 0) {
rds_tcp_keepalive(sock);
sock = NULL;
} else {
rds_tcp_restore_callbacks(sock, cp->cp_transport_data);
}
out:
mutex_unlock(&tc->t_conn_path_lock);
if (sock)
sock_release(sock);
return ret;
}
/*
* Before killing the tcp socket this needs to serialize with callbacks. The
* caller has already grabbed the sending sem so we're serialized with other
* senders.
*
* TCP calls the callbacks with the sock lock so we hold it while we reset the
* callbacks to those set by TCP. Our callbacks won't execute again once we
* hold the sock lock.
*/
void rds_tcp_conn_path_shutdown(struct rds_conn_path *cp)
{
struct rds_tcp_connection *tc = cp->cp_transport_data;
struct socket *sock = tc->t_sock;
rdsdebug("shutting down conn %p tc %p sock %p\n",
cp->cp_conn, tc, sock);
if (sock) {
if (rds_destroy_pending(cp->cp_conn))
sock_no_linger(sock->sk);
sock->ops->shutdown(sock, RCV_SHUTDOWN | SEND_SHUTDOWN);
lock_sock(sock->sk);
rds_tcp_restore_callbacks(sock, tc); /* tc->tc_sock = NULL */
release_sock(sock->sk);
sock_release(sock);
}
if (tc->t_tinc) {
rds_inc_put(&tc->t_tinc->ti_inc);
tc->t_tinc = NULL;
}
tc->t_tinc_hdr_rem = sizeof(struct rds_header);
tc->t_tinc_data_rem = 0;
}