linux/net/rxrpc/local_object.c
David Howells d12040b693 rxrpc: Fix lack of conn cleanup when local endpoint is cleaned up [ver #2]
When a local endpoint is ceases to be in use, such as when the kafs module
is unloaded, the kernel will emit an assertion failure if there are any
outstanding client connections:

	rxrpc: Assertion failed
	------------[ cut here ]------------
	kernel BUG at net/rxrpc/local_object.c:433!

and even beyond that, will evince other oopses if there are service
connections still present.

Fix this by:

 (1) Removing the triggering of connection reaping when an rxrpc socket is
     released.  These don't actually clean up the connections anyway - and
     further, the local endpoint may still be in use through another
     socket.

 (2) Mark the local endpoint as dead when we start the process of tearing
     it down.

 (3) When destroying a local endpoint, strip all of its client connections
     from the idle list and discard the ref on each that the list was
     holding.

 (4) When destroying a local endpoint, call the service connection reaper
     directly (rather than through a workqueue) to immediately kill off all
     outstanding service connections.

 (5) Make the service connection reaper reap connections for which the
     local endpoint is marked dead.

Only after destroying the connections can we close the socket lest we get
an oops in a workqueue that's looking at a connection or a peer.

Fixes: 3d18cbb7fd ("rxrpc: Fix conn expiry timers")
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-30 15:06:52 -07:00

524 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* Local endpoint object management
*
* Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/udp.h>
#include <linux/ip.h>
#include <linux/hashtable.h>
#include <net/sock.h>
#include <net/udp.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
static void rxrpc_local_processor(struct work_struct *);
static void rxrpc_local_rcu(struct rcu_head *);
/*
* Compare a local to an address. Return -ve, 0 or +ve to indicate less than,
* same or greater than.
*
* We explicitly don't compare the RxRPC service ID as we want to reject
* conflicting uses by differing services. Further, we don't want to share
* addresses with different options (IPv6), so we don't compare those bits
* either.
*/
static long rxrpc_local_cmp_key(const struct rxrpc_local *local,
const struct sockaddr_rxrpc *srx)
{
long diff;
diff = ((local->srx.transport_type - srx->transport_type) ?:
(local->srx.transport_len - srx->transport_len) ?:
(local->srx.transport.family - srx->transport.family));
if (diff != 0)
return diff;
switch (srx->transport.family) {
case AF_INET:
/* If the choice of UDP port is left up to the transport, then
* the endpoint record doesn't match.
*/
return ((u16 __force)local->srx.transport.sin.sin_port -
(u16 __force)srx->transport.sin.sin_port) ?:
memcmp(&local->srx.transport.sin.sin_addr,
&srx->transport.sin.sin_addr,
sizeof(struct in_addr));
#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
/* If the choice of UDP6 port is left up to the transport, then
* the endpoint record doesn't match.
*/
return ((u16 __force)local->srx.transport.sin6.sin6_port -
(u16 __force)srx->transport.sin6.sin6_port) ?:
memcmp(&local->srx.transport.sin6.sin6_addr,
&srx->transport.sin6.sin6_addr,
sizeof(struct in6_addr));
#endif
default:
BUG();
}
}
/*
* Allocate a new local endpoint.
*/
static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet,
const struct sockaddr_rxrpc *srx)
{
struct rxrpc_local *local;
local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
if (local) {
atomic_set(&local->usage, 1);
atomic_set(&local->active_users, 1);
local->rxnet = rxnet;
INIT_LIST_HEAD(&local->link);
INIT_WORK(&local->processor, rxrpc_local_processor);
init_rwsem(&local->defrag_sem);
skb_queue_head_init(&local->reject_queue);
skb_queue_head_init(&local->event_queue);
local->client_conns = RB_ROOT;
spin_lock_init(&local->client_conns_lock);
spin_lock_init(&local->lock);
rwlock_init(&local->services_lock);
local->debug_id = atomic_inc_return(&rxrpc_debug_id);
memcpy(&local->srx, srx, sizeof(*srx));
local->srx.srx_service = 0;
trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, NULL);
}
_leave(" = %p", local);
return local;
}
/*
* create the local socket
* - must be called with rxrpc_local_mutex locked
*/
static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
{
struct sock *usk;
int ret, opt;
_enter("%p{%d,%d}",
local, local->srx.transport_type, local->srx.transport.family);
/* create a socket to represent the local endpoint */
ret = sock_create_kern(net, local->srx.transport.family,
local->srx.transport_type, 0, &local->socket);
if (ret < 0) {
_leave(" = %d [socket]", ret);
return ret;
}
/* set the socket up */
usk = local->socket->sk;
inet_sk(usk)->mc_loop = 0;
/* Enable CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE conversion */
inet_inc_convert_csum(usk);
rcu_assign_sk_user_data(usk, local);
udp_sk(usk)->encap_type = UDP_ENCAP_RXRPC;
udp_sk(usk)->encap_rcv = rxrpc_input_packet;
udp_sk(usk)->encap_destroy = NULL;
udp_sk(usk)->gro_receive = NULL;
udp_sk(usk)->gro_complete = NULL;
udp_encap_enable();
#if IS_ENABLED(CONFIG_AF_RXRPC_IPV6)
if (local->srx.transport.family == AF_INET6)
udpv6_encap_enable();
#endif
usk->sk_error_report = rxrpc_error_report;
/* if a local address was supplied then bind it */
if (local->srx.transport_len > sizeof(sa_family_t)) {
_debug("bind");
ret = kernel_bind(local->socket,
(struct sockaddr *)&local->srx.transport,
local->srx.transport_len);
if (ret < 0) {
_debug("bind failed %d", ret);
goto error;
}
}
switch (local->srx.transport.family) {
case AF_INET6:
/* we want to receive ICMPv6 errors */
opt = 1;
ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_RECVERR,
(char *) &opt, sizeof(opt));
if (ret < 0) {
_debug("setsockopt failed");
goto error;
}
/* we want to set the don't fragment bit */
opt = IPV6_PMTUDISC_DO;
ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_MTU_DISCOVER,
(char *) &opt, sizeof(opt));
if (ret < 0) {
_debug("setsockopt failed");
goto error;
}
/* Fall through and set IPv4 options too otherwise we don't get
* errors from IPv4 packets sent through the IPv6 socket.
*/
/* Fall through */
case AF_INET:
/* we want to receive ICMP errors */
opt = 1;
ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
(char *) &opt, sizeof(opt));
if (ret < 0) {
_debug("setsockopt failed");
goto error;
}
/* we want to set the don't fragment bit */
opt = IP_PMTUDISC_DO;
ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
(char *) &opt, sizeof(opt));
if (ret < 0) {
_debug("setsockopt failed");
goto error;
}
/* We want receive timestamps. */
opt = 1;
ret = kernel_setsockopt(local->socket, SOL_SOCKET, SO_TIMESTAMPNS_OLD,
(char *)&opt, sizeof(opt));
if (ret < 0) {
_debug("setsockopt failed");
goto error;
}
break;
default:
BUG();
}
_leave(" = 0");
return 0;
error:
kernel_sock_shutdown(local->socket, SHUT_RDWR);
local->socket->sk->sk_user_data = NULL;
sock_release(local->socket);
local->socket = NULL;
_leave(" = %d", ret);
return ret;
}
/*
* Look up or create a new local endpoint using the specified local address.
*/
struct rxrpc_local *rxrpc_lookup_local(struct net *net,
const struct sockaddr_rxrpc *srx)
{
struct rxrpc_local *local;
struct rxrpc_net *rxnet = rxrpc_net(net);
struct list_head *cursor;
const char *age;
long diff;
int ret;
_enter("{%d,%d,%pISp}",
srx->transport_type, srx->transport.family, &srx->transport);
mutex_lock(&rxnet->local_mutex);
for (cursor = rxnet->local_endpoints.next;
cursor != &rxnet->local_endpoints;
cursor = cursor->next) {
local = list_entry(cursor, struct rxrpc_local, link);
diff = rxrpc_local_cmp_key(local, srx);
if (diff < 0)
continue;
if (diff > 0)
break;
/* Services aren't allowed to share transport sockets, so
* reject that here. It is possible that the object is dying -
* but it may also still have the local transport address that
* we want bound.
*/
if (srx->srx_service) {
local = NULL;
goto addr_in_use;
}
/* Found a match. We replace a dying object. Attempting to
* bind the transport socket may still fail if we're attempting
* to use a local address that the dying object is still using.
*/
if (!rxrpc_use_local(local))
break;
age = "old";
goto found;
}
local = rxrpc_alloc_local(rxnet, srx);
if (!local)
goto nomem;
ret = rxrpc_open_socket(local, net);
if (ret < 0)
goto sock_error;
if (cursor != &rxnet->local_endpoints)
list_replace_init(cursor, &local->link);
else
list_add_tail(&local->link, cursor);
age = "new";
found:
mutex_unlock(&rxnet->local_mutex);
_net("LOCAL %s %d {%pISp}",
age, local->debug_id, &local->srx.transport);
_leave(" = %p", local);
return local;
nomem:
ret = -ENOMEM;
sock_error:
mutex_unlock(&rxnet->local_mutex);
if (local)
call_rcu(&local->rcu, rxrpc_local_rcu);
_leave(" = %d", ret);
return ERR_PTR(ret);
addr_in_use:
mutex_unlock(&rxnet->local_mutex);
_leave(" = -EADDRINUSE");
return ERR_PTR(-EADDRINUSE);
}
/*
* Get a ref on a local endpoint.
*/
struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local)
{
const void *here = __builtin_return_address(0);
int n;
n = atomic_inc_return(&local->usage);
trace_rxrpc_local(local->debug_id, rxrpc_local_got, n, here);
return local;
}
/*
* Get a ref on a local endpoint unless its usage has already reached 0.
*/
struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local)
{
const void *here = __builtin_return_address(0);
if (local) {
int n = atomic_fetch_add_unless(&local->usage, 1, 0);
if (n > 0)
trace_rxrpc_local(local->debug_id, rxrpc_local_got,
n + 1, here);
else
local = NULL;
}
return local;
}
/*
* Queue a local endpoint and pass the caller's reference to the work item.
*/
void rxrpc_queue_local(struct rxrpc_local *local)
{
const void *here = __builtin_return_address(0);
unsigned int debug_id = local->debug_id;
int n = atomic_read(&local->usage);
if (rxrpc_queue_work(&local->processor))
trace_rxrpc_local(debug_id, rxrpc_local_queued, n, here);
else
rxrpc_put_local(local);
}
/*
* Drop a ref on a local endpoint.
*/
void rxrpc_put_local(struct rxrpc_local *local)
{
const void *here = __builtin_return_address(0);
int n;
if (local) {
n = atomic_dec_return(&local->usage);
trace_rxrpc_local(local->debug_id, rxrpc_local_put, n, here);
if (n == 0)
call_rcu(&local->rcu, rxrpc_local_rcu);
}
}
/*
* Start using a local endpoint.
*/
struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local)
{
unsigned int au;
local = rxrpc_get_local_maybe(local);
if (!local)
return NULL;
au = atomic_fetch_add_unless(&local->active_users, 1, 0);
if (au == 0) {
rxrpc_put_local(local);
return NULL;
}
return local;
}
/*
* Cease using a local endpoint. Once the number of active users reaches 0, we
* start the closure of the transport in the work processor.
*/
void rxrpc_unuse_local(struct rxrpc_local *local)
{
unsigned int au;
if (local) {
au = atomic_dec_return(&local->active_users);
if (au == 0)
rxrpc_queue_local(local);
else
rxrpc_put_local(local);
}
}
/*
* Destroy a local endpoint's socket and then hand the record to RCU to dispose
* of.
*
* Closing the socket cannot be done from bottom half context or RCU callback
* context because it might sleep.
*/
static void rxrpc_local_destroyer(struct rxrpc_local *local)
{
struct socket *socket = local->socket;
struct rxrpc_net *rxnet = local->rxnet;
_enter("%d", local->debug_id);
local->dead = true;
mutex_lock(&rxnet->local_mutex);
list_del_init(&local->link);
mutex_unlock(&rxnet->local_mutex);
rxrpc_clean_up_local_conns(local);
rxrpc_service_connection_reaper(&rxnet->service_conn_reaper);
ASSERT(!local->service);
if (socket) {
local->socket = NULL;
kernel_sock_shutdown(socket, SHUT_RDWR);
socket->sk->sk_user_data = NULL;
sock_release(socket);
}
/* At this point, there should be no more packets coming in to the
* local endpoint.
*/
rxrpc_purge_queue(&local->reject_queue);
rxrpc_purge_queue(&local->event_queue);
}
/*
* Process events on an endpoint. The work item carries a ref which
* we must release.
*/
static void rxrpc_local_processor(struct work_struct *work)
{
struct rxrpc_local *local =
container_of(work, struct rxrpc_local, processor);
bool again;
trace_rxrpc_local(local->debug_id, rxrpc_local_processing,
atomic_read(&local->usage), NULL);
do {
again = false;
if (atomic_read(&local->active_users) == 0) {
rxrpc_local_destroyer(local);
break;
}
if (!skb_queue_empty(&local->reject_queue)) {
rxrpc_reject_packets(local);
again = true;
}
if (!skb_queue_empty(&local->event_queue)) {
rxrpc_process_local_events(local);
again = true;
}
} while (again);
rxrpc_put_local(local);
}
/*
* Destroy a local endpoint after the RCU grace period expires.
*/
static void rxrpc_local_rcu(struct rcu_head *rcu)
{
struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu);
_enter("%d", local->debug_id);
ASSERT(!work_pending(&local->processor));
_net("DESTROY LOCAL %d", local->debug_id);
kfree(local);
_leave("");
}
/*
* Verify the local endpoint list is empty by this point.
*/
void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet)
{
struct rxrpc_local *local;
_enter("");
flush_workqueue(rxrpc_workqueue);
if (!list_empty(&rxnet->local_endpoints)) {
mutex_lock(&rxnet->local_mutex);
list_for_each_entry(local, &rxnet->local_endpoints, link) {
pr_err("AF_RXRPC: Leaked local %p {%d}\n",
local, atomic_read(&local->usage));
}
mutex_unlock(&rxnet->local_mutex);
BUG();
}
}