linux-stable/net/rxrpc/conn_object.c
David Howells 5627cc8b96 rxrpc: Provide more refcount helper functions
Provide refcount helper functions for connections so that the code doesn't
touch local or connection usage counts directly.

Also make it such that local and peer put functions can take a NULL
pointer.

Signed-off-by: David Howells <dhowells@redhat.com>
2016-06-22 09:17:51 +01:00

836 lines
20 KiB
C

/* RxRPC virtual connection handler
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/crypto.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
/*
* Time till a connection expires after last use (in seconds).
*/
unsigned int rxrpc_connection_expiry = 10 * 60;
static void rxrpc_connection_reaper(struct work_struct *work);
LIST_HEAD(rxrpc_connections);
DEFINE_RWLOCK(rxrpc_connection_lock);
static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
/*
* allocate a new client connection bundle
*/
static struct rxrpc_conn_bundle *rxrpc_alloc_bundle(gfp_t gfp)
{
struct rxrpc_conn_bundle *bundle;
_enter("");
bundle = kzalloc(sizeof(struct rxrpc_conn_bundle), gfp);
if (bundle) {
INIT_LIST_HEAD(&bundle->unused_conns);
INIT_LIST_HEAD(&bundle->avail_conns);
INIT_LIST_HEAD(&bundle->busy_conns);
init_waitqueue_head(&bundle->chanwait);
atomic_set(&bundle->usage, 1);
}
_leave(" = %p", bundle);
return bundle;
}
/*
* compare bundle parameters with what we're looking for
* - return -ve, 0 or +ve
*/
static inline
int rxrpc_cmp_bundle(const struct rxrpc_conn_bundle *bundle,
struct key *key, u16 service_id)
{
return (bundle->service_id - service_id) ?:
((unsigned long)bundle->key - (unsigned long)key);
}
/*
* get bundle of client connections that a client socket can make use of
*/
struct rxrpc_conn_bundle *rxrpc_get_bundle(struct rxrpc_sock *rx,
struct rxrpc_transport *trans,
struct key *key,
u16 service_id,
gfp_t gfp)
{
struct rxrpc_conn_bundle *bundle, *candidate;
struct rb_node *p, *parent, **pp;
_enter("%p{%x},%x,%hx,",
rx, key_serial(key), trans->debug_id, service_id);
/* search the extant bundles first for one that matches the specified
* user ID */
spin_lock(&trans->client_lock);
p = trans->bundles.rb_node;
while (p) {
bundle = rb_entry(p, struct rxrpc_conn_bundle, node);
if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
p = p->rb_left;
else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
p = p->rb_right;
else
goto found_extant_bundle;
}
spin_unlock(&trans->client_lock);
/* not yet present - create a candidate for a new record and then
* redo the search */
candidate = rxrpc_alloc_bundle(gfp);
if (!candidate) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
candidate->key = key_get(key);
candidate->service_id = service_id;
spin_lock(&trans->client_lock);
pp = &trans->bundles.rb_node;
parent = NULL;
while (*pp) {
parent = *pp;
bundle = rb_entry(parent, struct rxrpc_conn_bundle, node);
if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
pp = &(*pp)->rb_left;
else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
pp = &(*pp)->rb_right;
else
goto found_extant_second;
}
/* second search also failed; add the new bundle */
bundle = candidate;
candidate = NULL;
rb_link_node(&bundle->node, parent, pp);
rb_insert_color(&bundle->node, &trans->bundles);
spin_unlock(&trans->client_lock);
_net("BUNDLE new on trans %d", trans->debug_id);
_leave(" = %p [new]", bundle);
return bundle;
/* we found the bundle in the list immediately */
found_extant_bundle:
atomic_inc(&bundle->usage);
spin_unlock(&trans->client_lock);
_net("BUNDLE old on trans %d", trans->debug_id);
_leave(" = %p [extant %d]", bundle, atomic_read(&bundle->usage));
return bundle;
/* we found the bundle on the second time through the list */
found_extant_second:
atomic_inc(&bundle->usage);
spin_unlock(&trans->client_lock);
kfree(candidate);
_net("BUNDLE old2 on trans %d", trans->debug_id);
_leave(" = %p [second %d]", bundle, atomic_read(&bundle->usage));
return bundle;
}
/*
* release a bundle
*/
void rxrpc_put_bundle(struct rxrpc_transport *trans,
struct rxrpc_conn_bundle *bundle)
{
_enter("%p,%p{%d}",trans, bundle, atomic_read(&bundle->usage));
if (atomic_dec_and_lock(&bundle->usage, &trans->client_lock)) {
_debug("Destroy bundle");
rb_erase(&bundle->node, &trans->bundles);
spin_unlock(&trans->client_lock);
ASSERT(list_empty(&bundle->unused_conns));
ASSERT(list_empty(&bundle->avail_conns));
ASSERT(list_empty(&bundle->busy_conns));
ASSERTCMP(bundle->num_conns, ==, 0);
key_put(bundle->key);
kfree(bundle);
}
_leave("");
}
/*
* allocate a new connection
*/
static struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
{
struct rxrpc_connection *conn;
_enter("");
conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
if (conn) {
INIT_WORK(&conn->processor, &rxrpc_process_connection);
INIT_LIST_HEAD(&conn->bundle_link);
conn->calls = RB_ROOT;
skb_queue_head_init(&conn->rx_queue);
conn->security = &rxrpc_no_security;
rwlock_init(&conn->lock);
spin_lock_init(&conn->state_lock);
atomic_set(&conn->usage, 1);
conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
conn->avail_calls = RXRPC_MAXCALLS;
conn->size_align = 4;
conn->header_size = sizeof(struct rxrpc_wire_header);
}
_leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
return conn;
}
/*
* add a call to a connection's call-by-ID tree
*/
static void rxrpc_add_call_ID_to_conn(struct rxrpc_connection *conn,
struct rxrpc_call *call)
{
struct rxrpc_call *xcall;
struct rb_node *parent, **p;
__be32 call_id;
write_lock_bh(&conn->lock);
call_id = call->call_id;
p = &conn->calls.rb_node;
parent = NULL;
while (*p) {
parent = *p;
xcall = rb_entry(parent, struct rxrpc_call, conn_node);
if (call_id < xcall->call_id)
p = &(*p)->rb_left;
else if (call_id > xcall->call_id)
p = &(*p)->rb_right;
else
BUG();
}
rb_link_node(&call->conn_node, parent, p);
rb_insert_color(&call->conn_node, &conn->calls);
write_unlock_bh(&conn->lock);
}
/*
* Allocate a client connection.
*/
static struct rxrpc_connection *
rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp,
struct rxrpc_transport *trans,
gfp_t gfp)
{
struct rxrpc_connection *conn;
int ret;
_enter("");
conn = rxrpc_alloc_connection(gfp);
if (!conn) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
conn->params = *cp;
conn->proto.local = cp->local;
conn->proto.epoch = rxrpc_epoch;
conn->proto.cid = 0;
conn->proto.in_clientflag = 0;
conn->proto.family = cp->peer->srx.transport.family;
conn->out_clientflag = RXRPC_CLIENT_INITIATED;
conn->state = RXRPC_CONN_CLIENT;
switch (conn->proto.family) {
case AF_INET:
conn->proto.addr_size = sizeof(conn->proto.ipv4_addr);
conn->proto.ipv4_addr = cp->peer->srx.transport.sin.sin_addr;
conn->proto.port = cp->peer->srx.transport.sin.sin_port;
break;
}
ret = rxrpc_get_client_connection_id(conn, trans, gfp);
if (ret < 0)
goto error_0;
ret = rxrpc_init_client_conn_security(conn);
if (ret < 0)
goto error_1;
conn->security->prime_packet_security(conn);
write_lock(&rxrpc_connection_lock);
list_add_tail(&conn->link, &rxrpc_connections);
write_unlock(&rxrpc_connection_lock);
key_get(conn->params.key);
_leave(" = %p", conn);
return conn;
error_1:
rxrpc_put_client_connection_id(conn);
error_0:
kfree(conn);
_leave(" = %d", ret);
return ERR_PTR(ret);
}
/*
* connect a call on an exclusive connection
*/
static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
struct rxrpc_conn_parameters *cp,
struct rxrpc_transport *trans,
struct rxrpc_call *call,
gfp_t gfp)
{
struct rxrpc_connection *conn;
int chan;
_enter("");
conn = rxrpc_alloc_client_connection(cp, trans, gfp);
if (IS_ERR(conn)) {
_leave(" = %ld", PTR_ERR(conn));
return PTR_ERR(conn);
}
atomic_inc(&trans->usage);
conn->trans = trans;
conn->bundle = NULL;
_net("CONNECT EXCL new %d on TRANS %d",
conn->debug_id, conn->trans->debug_id);
/* Since no one else can use the connection, we just use the first
* channel.
*/
chan = 0;
rxrpc_get_connection(conn);
conn->avail_calls = RXRPC_MAXCALLS - 1;
conn->channels[chan] = call;
conn->call_counter = 1;
call->conn = conn;
call->channel = chan;
call->cid = conn->proto.cid | chan;
call->call_id = 1;
_net("CONNECT client on conn %d chan %d as call %x",
conn->debug_id, chan, call->call_id);
rxrpc_add_call_ID_to_conn(conn, call);
_leave(" = 0");
return 0;
}
/*
* find a connection for a call
* - called in process context with IRQs enabled
*/
int rxrpc_connect_call(struct rxrpc_sock *rx,
struct rxrpc_conn_parameters *cp,
struct rxrpc_transport *trans,
struct rxrpc_conn_bundle *bundle,
struct rxrpc_call *call,
gfp_t gfp)
{
struct rxrpc_connection *conn, *candidate;
int chan;
DECLARE_WAITQUEUE(myself, current);
_enter("%p,%lx,", rx, call->user_call_ID);
if (cp->exclusive)
return rxrpc_connect_exclusive(rx, cp, trans, call, gfp);
spin_lock(&trans->client_lock);
for (;;) {
/* see if the bundle has a call slot available */
if (!list_empty(&bundle->avail_conns)) {
_debug("avail");
conn = list_entry(bundle->avail_conns.next,
struct rxrpc_connection,
bundle_link);
if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
list_del_init(&conn->bundle_link);
bundle->num_conns--;
continue;
}
if (--conn->avail_calls == 0)
list_move(&conn->bundle_link,
&bundle->busy_conns);
ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
ASSERT(conn->channels[0] == NULL ||
conn->channels[1] == NULL ||
conn->channels[2] == NULL ||
conn->channels[3] == NULL);
rxrpc_get_connection(conn);
break;
}
if (!list_empty(&bundle->unused_conns)) {
_debug("unused");
conn = list_entry(bundle->unused_conns.next,
struct rxrpc_connection,
bundle_link);
if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
list_del_init(&conn->bundle_link);
bundle->num_conns--;
continue;
}
ASSERTCMP(conn->avail_calls, ==, RXRPC_MAXCALLS);
conn->avail_calls = RXRPC_MAXCALLS - 1;
ASSERT(conn->channels[0] == NULL &&
conn->channels[1] == NULL &&
conn->channels[2] == NULL &&
conn->channels[3] == NULL);
rxrpc_get_connection(conn);
list_move(&conn->bundle_link, &bundle->avail_conns);
break;
}
/* need to allocate a new connection */
_debug("get new conn [%d]", bundle->num_conns);
spin_unlock(&trans->client_lock);
if (signal_pending(current))
goto interrupted;
if (bundle->num_conns >= 20) {
_debug("too many conns");
if (!gfpflags_allow_blocking(gfp)) {
_leave(" = -EAGAIN");
return -EAGAIN;
}
add_wait_queue(&bundle->chanwait, &myself);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (bundle->num_conns < 20 ||
!list_empty(&bundle->unused_conns) ||
!list_empty(&bundle->avail_conns))
break;
if (signal_pending(current))
goto interrupted_dequeue;
schedule();
}
remove_wait_queue(&bundle->chanwait, &myself);
__set_current_state(TASK_RUNNING);
spin_lock(&trans->client_lock);
continue;
}
/* not yet present - create a candidate for a new connection and then
* redo the check */
candidate = rxrpc_alloc_client_connection(cp, trans, gfp);
if (!candidate) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
atomic_inc(&bundle->usage);
atomic_inc(&trans->usage);
candidate->trans = trans;
candidate->bundle = bundle;
spin_lock(&trans->client_lock);
list_add(&candidate->bundle_link, &bundle->unused_conns);
bundle->num_conns++;
_net("CONNECT new %d on TRANS %d",
candidate->debug_id, candidate->trans->debug_id);
/* leave the candidate lurking in zombie mode attached to the
* bundle until we're ready for it */
rxrpc_put_connection(candidate);
candidate = NULL;
}
/* we've got a connection with a free channel and we can now attach the
* call to it
* - we're holding the transport's client lock
* - we're holding a reference on the connection
* - we're holding a reference on the bundle
*/
for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
if (!conn->channels[chan])
goto found_channel;
ASSERT(conn->channels[0] == NULL ||
conn->channels[1] == NULL ||
conn->channels[2] == NULL ||
conn->channels[3] == NULL);
BUG();
found_channel:
conn->channels[chan] = call;
call->conn = conn;
call->channel = chan;
call->cid = conn->proto.cid | chan;
call->call_id = ++conn->call_counter;
_net("CONNECT client on conn %d chan %d as call %x",
conn->debug_id, chan, call->call_id);
ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
spin_unlock(&trans->client_lock);
rxrpc_add_call_ID_to_conn(conn, call);
_leave(" = 0");
return 0;
interrupted_dequeue:
remove_wait_queue(&bundle->chanwait, &myself);
__set_current_state(TASK_RUNNING);
interrupted:
_leave(" = -ERESTARTSYS");
return -ERESTARTSYS;
}
/*
* get a record of an incoming connection
*/
struct rxrpc_connection *
rxrpc_incoming_connection(struct rxrpc_transport *trans, struct sk_buff *skb)
{
struct rxrpc_connection *conn, *candidate = NULL;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct rb_node *p, **pp;
const char *new = "old";
__be32 epoch;
u32 cid;
_enter("");
ASSERT(sp->hdr.flags & RXRPC_CLIENT_INITIATED);
epoch = sp->hdr.epoch;
cid = sp->hdr.cid & RXRPC_CIDMASK;
/* search the connection list first */
read_lock_bh(&trans->conn_lock);
p = trans->server_conns.rb_node;
while (p) {
conn = rb_entry(p, struct rxrpc_connection, node);
_debug("maybe %x", conn->proto.cid);
if (epoch < conn->proto.epoch)
p = p->rb_left;
else if (epoch > conn->proto.epoch)
p = p->rb_right;
else if (cid < conn->proto.cid)
p = p->rb_left;
else if (cid > conn->proto.cid)
p = p->rb_right;
else
goto found_extant_connection;
}
read_unlock_bh(&trans->conn_lock);
/* not yet present - create a candidate for a new record and then
* redo the search */
candidate = rxrpc_alloc_connection(GFP_NOIO);
if (!candidate) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
candidate->trans = trans;
candidate->proto.local = trans->local;
candidate->proto.epoch = sp->hdr.epoch;
candidate->proto.cid = sp->hdr.cid & RXRPC_CIDMASK;
candidate->proto.in_clientflag = RXRPC_CLIENT_INITIATED;
candidate->params.local = trans->local;
candidate->params.peer = trans->peer;
candidate->params.service_id = sp->hdr.serviceId;
candidate->security_ix = sp->hdr.securityIndex;
candidate->out_clientflag = 0;
candidate->state = RXRPC_CONN_SERVER;
if (candidate->params.service_id)
candidate->state = RXRPC_CONN_SERVER_UNSECURED;
write_lock_bh(&trans->conn_lock);
pp = &trans->server_conns.rb_node;
p = NULL;
while (*pp) {
p = *pp;
conn = rb_entry(p, struct rxrpc_connection, node);
if (epoch < conn->proto.epoch)
pp = &(*pp)->rb_left;
else if (epoch > conn->proto.epoch)
pp = &(*pp)->rb_right;
else if (cid < conn->proto.cid)
pp = &(*pp)->rb_left;
else if (cid > conn->proto.cid)
pp = &(*pp)->rb_right;
else
goto found_extant_second;
}
/* we can now add the new candidate to the list */
conn = candidate;
candidate = NULL;
rb_link_node(&conn->node, p, pp);
rb_insert_color(&conn->node, &trans->server_conns);
atomic_inc(&conn->trans->usage);
write_unlock_bh(&trans->conn_lock);
write_lock(&rxrpc_connection_lock);
list_add_tail(&conn->link, &rxrpc_connections);
write_unlock(&rxrpc_connection_lock);
new = "new";
success:
_net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->proto.cid);
_leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
return conn;
/* we found the connection in the list immediately */
found_extant_connection:
if (sp->hdr.securityIndex != conn->security_ix) {
read_unlock_bh(&trans->conn_lock);
goto security_mismatch;
}
rxrpc_get_connection(conn);
read_unlock_bh(&trans->conn_lock);
goto success;
/* we found the connection on the second time through the list */
found_extant_second:
if (sp->hdr.securityIndex != conn->security_ix) {
write_unlock_bh(&trans->conn_lock);
goto security_mismatch;
}
rxrpc_get_connection(conn);
write_unlock_bh(&trans->conn_lock);
kfree(candidate);
goto success;
security_mismatch:
kfree(candidate);
_leave(" = -EKEYREJECTED");
return ERR_PTR(-EKEYREJECTED);
}
/*
* find a connection based on transport and RxRPC connection ID for an incoming
* packet
*/
struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_transport *trans,
struct sk_buff *skb)
{
struct rxrpc_connection *conn;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct rb_node *p;
u32 epoch, cid;
_enter(",{%x,%x}", sp->hdr.cid, sp->hdr.flags);
read_lock_bh(&trans->conn_lock);
cid = sp->hdr.cid & RXRPC_CIDMASK;
epoch = sp->hdr.epoch;
if (sp->hdr.flags & RXRPC_CLIENT_INITIATED) {
p = trans->server_conns.rb_node;
while (p) {
conn = rb_entry(p, struct rxrpc_connection, node);
_debug("maybe %x", conn->proto.cid);
if (epoch < conn->proto.epoch)
p = p->rb_left;
else if (epoch > conn->proto.epoch)
p = p->rb_right;
else if (cid < conn->proto.cid)
p = p->rb_left;
else if (cid > conn->proto.cid)
p = p->rb_right;
else
goto found;
}
} else {
conn = idr_find(&rxrpc_client_conn_ids, cid >> RXRPC_CIDSHIFT);
if (conn && conn->proto.epoch == epoch)
goto found;
}
read_unlock_bh(&trans->conn_lock);
_leave(" = NULL");
return NULL;
found:
rxrpc_get_connection(conn);
read_unlock_bh(&trans->conn_lock);
_leave(" = %p", conn);
return conn;
}
/*
* release a virtual connection
*/
void rxrpc_put_connection(struct rxrpc_connection *conn)
{
_enter("%p{u=%d,d=%d}",
conn, atomic_read(&conn->usage), conn->debug_id);
ASSERTCMP(atomic_read(&conn->usage), >, 0);
conn->put_time = ktime_get_seconds();
if (atomic_dec_and_test(&conn->usage)) {
_debug("zombie");
rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
}
_leave("");
}
/*
* destroy a virtual connection
*/
static void rxrpc_destroy_connection(struct rxrpc_connection *conn)
{
_enter("%p{%d}", conn, atomic_read(&conn->usage));
ASSERTCMP(atomic_read(&conn->usage), ==, 0);
_net("DESTROY CONN %d", conn->debug_id);
if (conn->bundle)
rxrpc_put_bundle(conn->trans, conn->bundle);
ASSERT(RB_EMPTY_ROOT(&conn->calls));
rxrpc_purge_queue(&conn->rx_queue);
conn->security->clear(conn);
key_put(conn->params.key);
key_put(conn->server_key);
rxrpc_put_transport(conn->trans);
kfree(conn);
_leave("");
}
/*
* reap dead connections
*/
static void rxrpc_connection_reaper(struct work_struct *work)
{
struct rxrpc_connection *conn, *_p;
unsigned long now, earliest, reap_time;
LIST_HEAD(graveyard);
_enter("");
now = ktime_get_seconds();
earliest = ULONG_MAX;
write_lock(&rxrpc_connection_lock);
list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
_debug("reap CONN %d { u=%d,t=%ld }",
conn->debug_id, atomic_read(&conn->usage),
(long) now - (long) conn->put_time);
if (likely(atomic_read(&conn->usage) > 0))
continue;
spin_lock(&conn->trans->client_lock);
write_lock_bh(&conn->trans->conn_lock);
reap_time = conn->put_time + rxrpc_connection_expiry;
if (atomic_read(&conn->usage) > 0) {
;
} else if (reap_time <= now) {
list_move_tail(&conn->link, &graveyard);
if (conn->out_clientflag)
rxrpc_put_client_connection_id(conn);
else
rb_erase(&conn->node,
&conn->trans->server_conns);
if (conn->bundle) {
list_del_init(&conn->bundle_link);
conn->bundle->num_conns--;
}
} else if (reap_time < earliest) {
earliest = reap_time;
}
write_unlock_bh(&conn->trans->conn_lock);
spin_unlock(&conn->trans->client_lock);
}
write_unlock(&rxrpc_connection_lock);
if (earliest != ULONG_MAX) {
_debug("reschedule reaper %ld", (long) earliest - now);
ASSERTCMP(earliest, >, now);
rxrpc_queue_delayed_work(&rxrpc_connection_reap,
(earliest - now) * HZ);
}
/* then destroy all those pulled out */
while (!list_empty(&graveyard)) {
conn = list_entry(graveyard.next, struct rxrpc_connection,
link);
list_del_init(&conn->link);
ASSERTCMP(atomic_read(&conn->usage), ==, 0);
rxrpc_destroy_connection(conn);
}
_leave("");
}
/*
* preemptively destroy all the connection records rather than waiting for them
* to time out
*/
void __exit rxrpc_destroy_all_connections(void)
{
_enter("");
rxrpc_connection_expiry = 0;
cancel_delayed_work(&rxrpc_connection_reap);
rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
_leave("");
}