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- // SPDX-License-Identifier: GPL-2.0-or-later
- /* Client connection-specific management code.
- *
- * Copyright (C) 2016, 2020 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells ([email protected])
- *
- * Client connections need to be cached for a little while after they've made a
- * call so as to handle retransmitted DATA packets in case the server didn't
- * receive the final ACK or terminating ABORT we sent it.
- *
- * There are flags of relevance to the cache:
- *
- * (2) DONT_REUSE - The connection should be discarded as soon as possible and
- * should not be reused. This is set when an exclusive connection is used
- * or a call ID counter overflows.
- *
- * The caching state may only be changed if the cache lock is held.
- *
- * There are two idle client connection expiry durations. If the total number
- * of connections is below the reap threshold, we use the normal duration; if
- * it's above, we use the fast duration.
- */
- #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
- #include <linux/slab.h>
- #include <linux/idr.h>
- #include <linux/timer.h>
- #include <linux/sched/signal.h>
- #include "ar-internal.h"
- __read_mostly unsigned int rxrpc_reap_client_connections = 900;
- __read_mostly unsigned long rxrpc_conn_idle_client_expiry = 2 * 60 * HZ;
- __read_mostly unsigned long rxrpc_conn_idle_client_fast_expiry = 2 * HZ;
- /*
- * We use machine-unique IDs for our client connections.
- */
- DEFINE_IDR(rxrpc_client_conn_ids);
- static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
- static void rxrpc_deactivate_bundle(struct rxrpc_bundle *bundle);
- /*
- * Get a connection ID and epoch for a client connection from the global pool.
- * The connection struct pointer is then recorded in the idr radix tree. The
- * epoch doesn't change until the client is rebooted (or, at least, unless the
- * module is unloaded).
- */
- static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
- gfp_t gfp)
- {
- struct rxrpc_net *rxnet = conn->params.local->rxnet;
- int id;
- _enter("");
- idr_preload(gfp);
- spin_lock(&rxrpc_conn_id_lock);
- id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn,
- 1, 0x40000000, GFP_NOWAIT);
- if (id < 0)
- goto error;
- spin_unlock(&rxrpc_conn_id_lock);
- idr_preload_end();
- conn->proto.epoch = rxnet->epoch;
- conn->proto.cid = id << RXRPC_CIDSHIFT;
- set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
- _leave(" [CID %x]", conn->proto.cid);
- return 0;
- error:
- spin_unlock(&rxrpc_conn_id_lock);
- idr_preload_end();
- _leave(" = %d", id);
- return id;
- }
- /*
- * Release a connection ID for a client connection from the global pool.
- */
- static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn)
- {
- if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) {
- spin_lock(&rxrpc_conn_id_lock);
- idr_remove(&rxrpc_client_conn_ids,
- conn->proto.cid >> RXRPC_CIDSHIFT);
- spin_unlock(&rxrpc_conn_id_lock);
- }
- }
- /*
- * Destroy the client connection ID tree.
- */
- void rxrpc_destroy_client_conn_ids(void)
- {
- struct rxrpc_connection *conn;
- int id;
- if (!idr_is_empty(&rxrpc_client_conn_ids)) {
- idr_for_each_entry(&rxrpc_client_conn_ids, conn, id) {
- pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
- conn, refcount_read(&conn->ref));
- }
- BUG();
- }
- idr_destroy(&rxrpc_client_conn_ids);
- }
- /*
- * Allocate a connection bundle.
- */
- static struct rxrpc_bundle *rxrpc_alloc_bundle(struct rxrpc_conn_parameters *cp,
- gfp_t gfp)
- {
- struct rxrpc_bundle *bundle;
- bundle = kzalloc(sizeof(*bundle), gfp);
- if (bundle) {
- bundle->params = *cp;
- rxrpc_get_peer(bundle->params.peer);
- refcount_set(&bundle->ref, 1);
- atomic_set(&bundle->active, 1);
- spin_lock_init(&bundle->channel_lock);
- INIT_LIST_HEAD(&bundle->waiting_calls);
- }
- return bundle;
- }
- struct rxrpc_bundle *rxrpc_get_bundle(struct rxrpc_bundle *bundle)
- {
- refcount_inc(&bundle->ref);
- return bundle;
- }
- static void rxrpc_free_bundle(struct rxrpc_bundle *bundle)
- {
- rxrpc_put_peer(bundle->params.peer);
- kfree(bundle);
- }
- void rxrpc_put_bundle(struct rxrpc_bundle *bundle)
- {
- unsigned int d = bundle->debug_id;
- bool dead;
- int r;
- dead = __refcount_dec_and_test(&bundle->ref, &r);
- _debug("PUT B=%x %d", d, r - 1);
- if (dead)
- rxrpc_free_bundle(bundle);
- }
- /*
- * Allocate a client connection.
- */
- static struct rxrpc_connection *
- rxrpc_alloc_client_connection(struct rxrpc_bundle *bundle, gfp_t gfp)
- {
- struct rxrpc_connection *conn;
- struct rxrpc_net *rxnet = bundle->params.local->rxnet;
- int ret;
- _enter("");
- conn = rxrpc_alloc_connection(gfp);
- if (!conn) {
- _leave(" = -ENOMEM");
- return ERR_PTR(-ENOMEM);
- }
- refcount_set(&conn->ref, 1);
- conn->bundle = bundle;
- conn->params = bundle->params;
- conn->out_clientflag = RXRPC_CLIENT_INITIATED;
- conn->state = RXRPC_CONN_CLIENT;
- conn->service_id = conn->params.service_id;
- ret = rxrpc_get_client_connection_id(conn, gfp);
- if (ret < 0)
- goto error_0;
- ret = rxrpc_init_client_conn_security(conn);
- if (ret < 0)
- goto error_1;
- atomic_inc(&rxnet->nr_conns);
- write_lock(&rxnet->conn_lock);
- list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
- write_unlock(&rxnet->conn_lock);
- rxrpc_get_bundle(bundle);
- rxrpc_get_peer(conn->params.peer);
- rxrpc_get_local(conn->params.local);
- key_get(conn->params.key);
- trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_client,
- refcount_read(&conn->ref),
- __builtin_return_address(0));
- atomic_inc(&rxnet->nr_client_conns);
- trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
- _leave(" = %p", conn);
- return conn;
- error_1:
- rxrpc_put_client_connection_id(conn);
- error_0:
- kfree(conn);
- _leave(" = %d", ret);
- return ERR_PTR(ret);
- }
- /*
- * Determine if a connection may be reused.
- */
- static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
- {
- struct rxrpc_net *rxnet;
- int id_cursor, id, distance, limit;
- if (!conn)
- goto dont_reuse;
- rxnet = conn->params.local->rxnet;
- if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
- goto dont_reuse;
- if (conn->state != RXRPC_CONN_CLIENT ||
- conn->proto.epoch != rxnet->epoch)
- goto mark_dont_reuse;
- /* The IDR tree gets very expensive on memory if the connection IDs are
- * widely scattered throughout the number space, so we shall want to
- * kill off connections that, say, have an ID more than about four
- * times the maximum number of client conns away from the current
- * allocation point to try and keep the IDs concentrated.
- */
- id_cursor = idr_get_cursor(&rxrpc_client_conn_ids);
- id = conn->proto.cid >> RXRPC_CIDSHIFT;
- distance = id - id_cursor;
- if (distance < 0)
- distance = -distance;
- limit = max_t(unsigned long, atomic_read(&rxnet->nr_conns) * 4, 1024);
- if (distance > limit)
- goto mark_dont_reuse;
- return true;
- mark_dont_reuse:
- set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
- dont_reuse:
- return false;
- }
- /*
- * Look up the conn bundle that matches the connection parameters, adding it if
- * it doesn't yet exist.
- */
- static struct rxrpc_bundle *rxrpc_look_up_bundle(struct rxrpc_conn_parameters *cp,
- gfp_t gfp)
- {
- static atomic_t rxrpc_bundle_id;
- struct rxrpc_bundle *bundle, *candidate;
- struct rxrpc_local *local = cp->local;
- struct rb_node *p, **pp, *parent;
- long diff;
- _enter("{%px,%x,%u,%u}",
- cp->peer, key_serial(cp->key), cp->security_level, cp->upgrade);
- if (cp->exclusive)
- return rxrpc_alloc_bundle(cp, gfp);
- /* First, see if the bundle is already there. */
- _debug("search 1");
- spin_lock(&local->client_bundles_lock);
- p = local->client_bundles.rb_node;
- while (p) {
- bundle = rb_entry(p, struct rxrpc_bundle, local_node);
- #define cmp(X) ((long)bundle->params.X - (long)cp->X)
- diff = (cmp(peer) ?:
- cmp(key) ?:
- cmp(security_level) ?:
- cmp(upgrade));
- #undef cmp
- if (diff < 0)
- p = p->rb_left;
- else if (diff > 0)
- p = p->rb_right;
- else
- goto found_bundle;
- }
- spin_unlock(&local->client_bundles_lock);
- _debug("not found");
- /* It wasn't. We need to add one. */
- candidate = rxrpc_alloc_bundle(cp, gfp);
- if (!candidate)
- return NULL;
- _debug("search 2");
- spin_lock(&local->client_bundles_lock);
- pp = &local->client_bundles.rb_node;
- parent = NULL;
- while (*pp) {
- parent = *pp;
- bundle = rb_entry(parent, struct rxrpc_bundle, local_node);
- #define cmp(X) ((long)bundle->params.X - (long)cp->X)
- diff = (cmp(peer) ?:
- cmp(key) ?:
- cmp(security_level) ?:
- cmp(upgrade));
- #undef cmp
- if (diff < 0)
- pp = &(*pp)->rb_left;
- else if (diff > 0)
- pp = &(*pp)->rb_right;
- else
- goto found_bundle_free;
- }
- _debug("new bundle");
- candidate->debug_id = atomic_inc_return(&rxrpc_bundle_id);
- rb_link_node(&candidate->local_node, parent, pp);
- rb_insert_color(&candidate->local_node, &local->client_bundles);
- rxrpc_get_bundle(candidate);
- spin_unlock(&local->client_bundles_lock);
- _leave(" = %u [new]", candidate->debug_id);
- return candidate;
- found_bundle_free:
- rxrpc_free_bundle(candidate);
- found_bundle:
- rxrpc_get_bundle(bundle);
- atomic_inc(&bundle->active);
- spin_unlock(&local->client_bundles_lock);
- _leave(" = %u [found]", bundle->debug_id);
- return bundle;
- }
- /*
- * Create or find a client bundle to use for a call.
- *
- * If we return with a connection, the call will be on its waiting list. It's
- * left to the caller to assign a channel and wake up the call.
- */
- static struct rxrpc_bundle *rxrpc_prep_call(struct rxrpc_sock *rx,
- struct rxrpc_call *call,
- struct rxrpc_conn_parameters *cp,
- struct sockaddr_rxrpc *srx,
- gfp_t gfp)
- {
- struct rxrpc_bundle *bundle;
- _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
- cp->peer = rxrpc_lookup_peer(rx, cp->local, srx, gfp);
- if (!cp->peer)
- goto error;
- call->cong_cwnd = cp->peer->cong_cwnd;
- if (call->cong_cwnd >= call->cong_ssthresh)
- call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
- else
- call->cong_mode = RXRPC_CALL_SLOW_START;
- if (cp->upgrade)
- __set_bit(RXRPC_CALL_UPGRADE, &call->flags);
- /* Find the client connection bundle. */
- bundle = rxrpc_look_up_bundle(cp, gfp);
- if (!bundle)
- goto error;
- /* Get this call queued. Someone else may activate it whilst we're
- * lining up a new connection, but that's fine.
- */
- spin_lock(&bundle->channel_lock);
- list_add_tail(&call->chan_wait_link, &bundle->waiting_calls);
- spin_unlock(&bundle->channel_lock);
- _leave(" = [B=%x]", bundle->debug_id);
- return bundle;
- error:
- _leave(" = -ENOMEM");
- return ERR_PTR(-ENOMEM);
- }
- /*
- * Allocate a new connection and add it into a bundle.
- */
- static void rxrpc_add_conn_to_bundle(struct rxrpc_bundle *bundle, gfp_t gfp)
- __releases(bundle->channel_lock)
- {
- struct rxrpc_connection *candidate = NULL, *old = NULL;
- bool conflict;
- int i;
- _enter("");
- conflict = bundle->alloc_conn;
- if (!conflict)
- bundle->alloc_conn = true;
- spin_unlock(&bundle->channel_lock);
- if (conflict) {
- _leave(" [conf]");
- return;
- }
- candidate = rxrpc_alloc_client_connection(bundle, gfp);
- spin_lock(&bundle->channel_lock);
- bundle->alloc_conn = false;
- if (IS_ERR(candidate)) {
- bundle->alloc_error = PTR_ERR(candidate);
- spin_unlock(&bundle->channel_lock);
- _leave(" [err %ld]", PTR_ERR(candidate));
- return;
- }
- bundle->alloc_error = 0;
- for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) {
- unsigned int shift = i * RXRPC_MAXCALLS;
- int j;
- old = bundle->conns[i];
- if (!rxrpc_may_reuse_conn(old)) {
- if (old)
- trace_rxrpc_client(old, -1, rxrpc_client_replace);
- candidate->bundle_shift = shift;
- atomic_inc(&bundle->active);
- bundle->conns[i] = candidate;
- for (j = 0; j < RXRPC_MAXCALLS; j++)
- set_bit(shift + j, &bundle->avail_chans);
- candidate = NULL;
- break;
- }
- old = NULL;
- }
- spin_unlock(&bundle->channel_lock);
- if (candidate) {
- _debug("discard C=%x", candidate->debug_id);
- trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate);
- rxrpc_put_connection(candidate);
- }
- rxrpc_put_connection(old);
- _leave("");
- }
- /*
- * Add a connection to a bundle if there are no usable connections or we have
- * connections waiting for extra capacity.
- */
- static void rxrpc_maybe_add_conn(struct rxrpc_bundle *bundle, gfp_t gfp)
- {
- struct rxrpc_call *call;
- int i, usable;
- _enter("");
- spin_lock(&bundle->channel_lock);
- /* See if there are any usable connections. */
- usable = 0;
- for (i = 0; i < ARRAY_SIZE(bundle->conns); i++)
- if (rxrpc_may_reuse_conn(bundle->conns[i]))
- usable++;
- if (!usable && !list_empty(&bundle->waiting_calls)) {
- call = list_first_entry(&bundle->waiting_calls,
- struct rxrpc_call, chan_wait_link);
- if (test_bit(RXRPC_CALL_UPGRADE, &call->flags))
- bundle->try_upgrade = true;
- }
- if (!usable)
- goto alloc_conn;
- if (!bundle->avail_chans &&
- !bundle->try_upgrade &&
- !list_empty(&bundle->waiting_calls) &&
- usable < ARRAY_SIZE(bundle->conns))
- goto alloc_conn;
- spin_unlock(&bundle->channel_lock);
- _leave("");
- return;
- alloc_conn:
- return rxrpc_add_conn_to_bundle(bundle, gfp);
- }
- /*
- * Assign a channel to the call at the front of the queue and wake the call up.
- * We don't increment the callNumber counter until this number has been exposed
- * to the world.
- */
- static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
- unsigned int channel)
- {
- struct rxrpc_channel *chan = &conn->channels[channel];
- struct rxrpc_bundle *bundle = conn->bundle;
- struct rxrpc_call *call = list_entry(bundle->waiting_calls.next,
- struct rxrpc_call, chan_wait_link);
- u32 call_id = chan->call_counter + 1;
- _enter("C=%x,%u", conn->debug_id, channel);
- trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
- /* Cancel the final ACK on the previous call if it hasn't been sent yet
- * as the DATA packet will implicitly ACK it.
- */
- clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
- clear_bit(conn->bundle_shift + channel, &bundle->avail_chans);
- rxrpc_see_call(call);
- list_del_init(&call->chan_wait_link);
- call->peer = rxrpc_get_peer(conn->params.peer);
- call->conn = rxrpc_get_connection(conn);
- call->cid = conn->proto.cid | channel;
- call->call_id = call_id;
- call->security = conn->security;
- call->security_ix = conn->security_ix;
- call->service_id = conn->service_id;
- trace_rxrpc_connect_call(call);
- _net("CONNECT call %08x:%08x as call %d on conn %d",
- call->cid, call->call_id, call->debug_id, conn->debug_id);
- write_lock_bh(&call->state_lock);
- call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
- write_unlock_bh(&call->state_lock);
- /* Paired with the read barrier in rxrpc_connect_call(). This orders
- * cid and epoch in the connection wrt to call_id without the need to
- * take the channel_lock.
- *
- * We provisionally assign a callNumber at this point, but we don't
- * confirm it until the call is about to be exposed.
- *
- * TODO: Pair with a barrier in the data_ready handler when that looks
- * at the call ID through a connection channel.
- */
- smp_wmb();
- chan->call_id = call_id;
- chan->call_debug_id = call->debug_id;
- rcu_assign_pointer(chan->call, call);
- wake_up(&call->waitq);
- }
- /*
- * Remove a connection from the idle list if it's on it.
- */
- static void rxrpc_unidle_conn(struct rxrpc_bundle *bundle, struct rxrpc_connection *conn)
- {
- struct rxrpc_net *rxnet = bundle->params.local->rxnet;
- bool drop_ref;
- if (!list_empty(&conn->cache_link)) {
- drop_ref = false;
- spin_lock(&rxnet->client_conn_cache_lock);
- if (!list_empty(&conn->cache_link)) {
- list_del_init(&conn->cache_link);
- drop_ref = true;
- }
- spin_unlock(&rxnet->client_conn_cache_lock);
- if (drop_ref)
- rxrpc_put_connection(conn);
- }
- }
- /*
- * Assign channels and callNumbers to waiting calls with channel_lock
- * held by caller.
- */
- static void rxrpc_activate_channels_locked(struct rxrpc_bundle *bundle)
- {
- struct rxrpc_connection *conn;
- unsigned long avail, mask;
- unsigned int channel, slot;
- if (bundle->try_upgrade)
- mask = 1;
- else
- mask = ULONG_MAX;
- while (!list_empty(&bundle->waiting_calls)) {
- avail = bundle->avail_chans & mask;
- if (!avail)
- break;
- channel = __ffs(avail);
- clear_bit(channel, &bundle->avail_chans);
- slot = channel / RXRPC_MAXCALLS;
- conn = bundle->conns[slot];
- if (!conn)
- break;
- if (bundle->try_upgrade)
- set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
- rxrpc_unidle_conn(bundle, conn);
- channel &= (RXRPC_MAXCALLS - 1);
- conn->act_chans |= 1 << channel;
- rxrpc_activate_one_channel(conn, channel);
- }
- }
- /*
- * Assign channels and callNumbers to waiting calls.
- */
- static void rxrpc_activate_channels(struct rxrpc_bundle *bundle)
- {
- _enter("B=%x", bundle->debug_id);
- trace_rxrpc_client(NULL, -1, rxrpc_client_activate_chans);
- if (!bundle->avail_chans)
- return;
- spin_lock(&bundle->channel_lock);
- rxrpc_activate_channels_locked(bundle);
- spin_unlock(&bundle->channel_lock);
- _leave("");
- }
- /*
- * Wait for a callNumber and a channel to be granted to a call.
- */
- static int rxrpc_wait_for_channel(struct rxrpc_bundle *bundle,
- struct rxrpc_call *call, gfp_t gfp)
- {
- DECLARE_WAITQUEUE(myself, current);
- int ret = 0;
- _enter("%d", call->debug_id);
- if (!gfpflags_allow_blocking(gfp)) {
- rxrpc_maybe_add_conn(bundle, gfp);
- rxrpc_activate_channels(bundle);
- ret = bundle->alloc_error ?: -EAGAIN;
- goto out;
- }
- add_wait_queue_exclusive(&call->waitq, &myself);
- for (;;) {
- rxrpc_maybe_add_conn(bundle, gfp);
- rxrpc_activate_channels(bundle);
- ret = bundle->alloc_error;
- if (ret < 0)
- break;
- switch (call->interruptibility) {
- case RXRPC_INTERRUPTIBLE:
- case RXRPC_PREINTERRUPTIBLE:
- set_current_state(TASK_INTERRUPTIBLE);
- break;
- case RXRPC_UNINTERRUPTIBLE:
- default:
- set_current_state(TASK_UNINTERRUPTIBLE);
- break;
- }
- if (READ_ONCE(call->state) != RXRPC_CALL_CLIENT_AWAIT_CONN)
- break;
- if ((call->interruptibility == RXRPC_INTERRUPTIBLE ||
- call->interruptibility == RXRPC_PREINTERRUPTIBLE) &&
- signal_pending(current)) {
- ret = -ERESTARTSYS;
- break;
- }
- schedule();
- }
- remove_wait_queue(&call->waitq, &myself);
- __set_current_state(TASK_RUNNING);
- out:
- _leave(" = %d", ret);
- return ret;
- }
- /*
- * find a connection for a call
- * - called in process context with IRQs enabled
- */
- int rxrpc_connect_call(struct rxrpc_sock *rx,
- struct rxrpc_call *call,
- struct rxrpc_conn_parameters *cp,
- struct sockaddr_rxrpc *srx,
- gfp_t gfp)
- {
- struct rxrpc_bundle *bundle;
- struct rxrpc_net *rxnet = cp->local->rxnet;
- int ret = 0;
- _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
- rxrpc_discard_expired_client_conns(&rxnet->client_conn_reaper);
- bundle = rxrpc_prep_call(rx, call, cp, srx, gfp);
- if (IS_ERR(bundle)) {
- ret = PTR_ERR(bundle);
- goto out;
- }
- if (call->state == RXRPC_CALL_CLIENT_AWAIT_CONN) {
- ret = rxrpc_wait_for_channel(bundle, call, gfp);
- if (ret < 0)
- goto wait_failed;
- }
- granted_channel:
- /* Paired with the write barrier in rxrpc_activate_one_channel(). */
- smp_rmb();
- out_put_bundle:
- rxrpc_deactivate_bundle(bundle);
- rxrpc_put_bundle(bundle);
- out:
- _leave(" = %d", ret);
- return ret;
- wait_failed:
- spin_lock(&bundle->channel_lock);
- list_del_init(&call->chan_wait_link);
- spin_unlock(&bundle->channel_lock);
- if (call->state != RXRPC_CALL_CLIENT_AWAIT_CONN) {
- ret = 0;
- goto granted_channel;
- }
- trace_rxrpc_client(call->conn, ret, rxrpc_client_chan_wait_failed);
- rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, 0, ret);
- rxrpc_disconnect_client_call(bundle, call);
- goto out_put_bundle;
- }
- /*
- * Note that a call, and thus a connection, is about to be exposed to the
- * world.
- */
- void rxrpc_expose_client_call(struct rxrpc_call *call)
- {
- unsigned int channel = call->cid & RXRPC_CHANNELMASK;
- struct rxrpc_connection *conn = call->conn;
- struct rxrpc_channel *chan = &conn->channels[channel];
- if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
- /* Mark the call ID as being used. If the callNumber counter
- * exceeds ~2 billion, we kill the connection after its
- * outstanding calls have finished so that the counter doesn't
- * wrap.
- */
- chan->call_counter++;
- if (chan->call_counter >= INT_MAX)
- set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
- trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
- }
- }
- /*
- * Set the reap timer.
- */
- static void rxrpc_set_client_reap_timer(struct rxrpc_net *rxnet)
- {
- if (!rxnet->kill_all_client_conns) {
- unsigned long now = jiffies;
- unsigned long reap_at = now + rxrpc_conn_idle_client_expiry;
- if (rxnet->live)
- timer_reduce(&rxnet->client_conn_reap_timer, reap_at);
- }
- }
- /*
- * Disconnect a client call.
- */
- void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call *call)
- {
- struct rxrpc_connection *conn;
- struct rxrpc_channel *chan = NULL;
- struct rxrpc_net *rxnet = bundle->params.local->rxnet;
- unsigned int channel;
- bool may_reuse;
- u32 cid;
- _enter("c=%x", call->debug_id);
- spin_lock(&bundle->channel_lock);
- set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
- /* Calls that have never actually been assigned a channel can simply be
- * discarded.
- */
- conn = call->conn;
- if (!conn) {
- _debug("call is waiting");
- ASSERTCMP(call->call_id, ==, 0);
- ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
- list_del_init(&call->chan_wait_link);
- goto out;
- }
- cid = call->cid;
- channel = cid & RXRPC_CHANNELMASK;
- chan = &conn->channels[channel];
- trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
- if (rcu_access_pointer(chan->call) != call) {
- spin_unlock(&bundle->channel_lock);
- BUG();
- }
- may_reuse = rxrpc_may_reuse_conn(conn);
- /* If a client call was exposed to the world, we save the result for
- * retransmission.
- *
- * We use a barrier here so that the call number and abort code can be
- * read without needing to take a lock.
- *
- * TODO: Make the incoming packet handler check this and handle
- * terminal retransmission without requiring access to the call.
- */
- if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
- _debug("exposed %u,%u", call->call_id, call->abort_code);
- __rxrpc_disconnect_call(conn, call);
- if (test_and_clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) {
- trace_rxrpc_client(conn, channel, rxrpc_client_to_active);
- bundle->try_upgrade = false;
- if (may_reuse)
- rxrpc_activate_channels_locked(bundle);
- }
- }
- /* See if we can pass the channel directly to another call. */
- if (may_reuse && !list_empty(&bundle->waiting_calls)) {
- trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
- rxrpc_activate_one_channel(conn, channel);
- goto out;
- }
- /* Schedule the final ACK to be transmitted in a short while so that it
- * can be skipped if we find a follow-on call. The first DATA packet
- * of the follow on call will implicitly ACK this call.
- */
- if (call->completion == RXRPC_CALL_SUCCEEDED &&
- test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
- unsigned long final_ack_at = jiffies + 2;
- WRITE_ONCE(chan->final_ack_at, final_ack_at);
- smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */
- set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
- rxrpc_reduce_conn_timer(conn, final_ack_at);
- }
- /* Deactivate the channel. */
- rcu_assign_pointer(chan->call, NULL);
- set_bit(conn->bundle_shift + channel, &conn->bundle->avail_chans);
- conn->act_chans &= ~(1 << channel);
- /* If no channels remain active, then put the connection on the idle
- * list for a short while. Give it a ref to stop it going away if it
- * becomes unbundled.
- */
- if (!conn->act_chans) {
- trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
- conn->idle_timestamp = jiffies;
- rxrpc_get_connection(conn);
- spin_lock(&rxnet->client_conn_cache_lock);
- list_move_tail(&conn->cache_link, &rxnet->idle_client_conns);
- spin_unlock(&rxnet->client_conn_cache_lock);
- rxrpc_set_client_reap_timer(rxnet);
- }
- out:
- spin_unlock(&bundle->channel_lock);
- _leave("");
- return;
- }
- /*
- * Remove a connection from a bundle.
- */
- static void rxrpc_unbundle_conn(struct rxrpc_connection *conn)
- {
- struct rxrpc_bundle *bundle = conn->bundle;
- unsigned int bindex;
- bool need_drop = false;
- int i;
- _enter("C=%x", conn->debug_id);
- if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
- rxrpc_process_delayed_final_acks(conn, true);
- spin_lock(&bundle->channel_lock);
- bindex = conn->bundle_shift / RXRPC_MAXCALLS;
- if (bundle->conns[bindex] == conn) {
- _debug("clear slot %u", bindex);
- bundle->conns[bindex] = NULL;
- for (i = 0; i < RXRPC_MAXCALLS; i++)
- clear_bit(conn->bundle_shift + i, &bundle->avail_chans);
- need_drop = true;
- }
- spin_unlock(&bundle->channel_lock);
- if (need_drop) {
- rxrpc_deactivate_bundle(bundle);
- rxrpc_put_connection(conn);
- }
- }
- /*
- * Drop the active count on a bundle.
- */
- static void rxrpc_deactivate_bundle(struct rxrpc_bundle *bundle)
- {
- struct rxrpc_local *local = bundle->params.local;
- bool need_put = false;
- if (atomic_dec_and_lock(&bundle->active, &local->client_bundles_lock)) {
- if (!bundle->params.exclusive) {
- _debug("erase bundle");
- rb_erase(&bundle->local_node, &local->client_bundles);
- need_put = true;
- }
- spin_unlock(&local->client_bundles_lock);
- if (need_put)
- rxrpc_put_bundle(bundle);
- }
- }
- /*
- * Clean up a dead client connection.
- */
- static void rxrpc_kill_client_conn(struct rxrpc_connection *conn)
- {
- struct rxrpc_local *local = conn->params.local;
- struct rxrpc_net *rxnet = local->rxnet;
- _enter("C=%x", conn->debug_id);
- trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
- atomic_dec(&rxnet->nr_client_conns);
- rxrpc_put_client_connection_id(conn);
- rxrpc_kill_connection(conn);
- }
- /*
- * Clean up a dead client connections.
- */
- void rxrpc_put_client_conn(struct rxrpc_connection *conn)
- {
- const void *here = __builtin_return_address(0);
- unsigned int debug_id = conn->debug_id;
- bool dead;
- int r;
- dead = __refcount_dec_and_test(&conn->ref, &r);
- trace_rxrpc_conn(debug_id, rxrpc_conn_put_client, r - 1, here);
- if (dead)
- rxrpc_kill_client_conn(conn);
- }
- /*
- * Discard expired client connections from the idle list. Each conn in the
- * idle list has been exposed and holds an extra ref because of that.
- *
- * This may be called from conn setup or from a work item so cannot be
- * considered non-reentrant.
- */
- void rxrpc_discard_expired_client_conns(struct work_struct *work)
- {
- struct rxrpc_connection *conn;
- struct rxrpc_net *rxnet =
- container_of(work, struct rxrpc_net, client_conn_reaper);
- unsigned long expiry, conn_expires_at, now;
- unsigned int nr_conns;
- _enter("");
- if (list_empty(&rxnet->idle_client_conns)) {
- _leave(" [empty]");
- return;
- }
- /* Don't double up on the discarding */
- if (!spin_trylock(&rxnet->client_conn_discard_lock)) {
- _leave(" [already]");
- return;
- }
- /* We keep an estimate of what the number of conns ought to be after
- * we've discarded some so that we don't overdo the discarding.
- */
- nr_conns = atomic_read(&rxnet->nr_client_conns);
- next:
- spin_lock(&rxnet->client_conn_cache_lock);
- if (list_empty(&rxnet->idle_client_conns))
- goto out;
- conn = list_entry(rxnet->idle_client_conns.next,
- struct rxrpc_connection, cache_link);
- if (!rxnet->kill_all_client_conns) {
- /* If the number of connections is over the reap limit, we
- * expedite discard by reducing the expiry timeout. We must,
- * however, have at least a short grace period to be able to do
- * final-ACK or ABORT retransmission.
- */
- expiry = rxrpc_conn_idle_client_expiry;
- if (nr_conns > rxrpc_reap_client_connections)
- expiry = rxrpc_conn_idle_client_fast_expiry;
- if (conn->params.local->service_closed)
- expiry = rxrpc_closed_conn_expiry * HZ;
- conn_expires_at = conn->idle_timestamp + expiry;
- now = READ_ONCE(jiffies);
- if (time_after(conn_expires_at, now))
- goto not_yet_expired;
- }
- trace_rxrpc_client(conn, -1, rxrpc_client_discard);
- list_del_init(&conn->cache_link);
- spin_unlock(&rxnet->client_conn_cache_lock);
- rxrpc_unbundle_conn(conn);
- rxrpc_put_connection(conn); /* Drop the ->cache_link ref */
- nr_conns--;
- goto next;
- not_yet_expired:
- /* The connection at the front of the queue hasn't yet expired, so
- * schedule the work item for that point if we discarded something.
- *
- * We don't worry if the work item is already scheduled - it can look
- * after rescheduling itself at a later time. We could cancel it, but
- * then things get messier.
- */
- _debug("not yet");
- if (!rxnet->kill_all_client_conns)
- timer_reduce(&rxnet->client_conn_reap_timer, conn_expires_at);
- out:
- spin_unlock(&rxnet->client_conn_cache_lock);
- spin_unlock(&rxnet->client_conn_discard_lock);
- _leave("");
- }
- /*
- * Preemptively destroy all the client connection records rather than waiting
- * for them to time out
- */
- void rxrpc_destroy_all_client_connections(struct rxrpc_net *rxnet)
- {
- _enter("");
- spin_lock(&rxnet->client_conn_cache_lock);
- rxnet->kill_all_client_conns = true;
- spin_unlock(&rxnet->client_conn_cache_lock);
- del_timer_sync(&rxnet->client_conn_reap_timer);
- if (!rxrpc_queue_work(&rxnet->client_conn_reaper))
- _debug("destroy: queue failed");
- _leave("");
- }
- /*
- * Clean up the client connections on a local endpoint.
- */
- void rxrpc_clean_up_local_conns(struct rxrpc_local *local)
- {
- struct rxrpc_connection *conn, *tmp;
- struct rxrpc_net *rxnet = local->rxnet;
- LIST_HEAD(graveyard);
- _enter("");
- spin_lock(&rxnet->client_conn_cache_lock);
- list_for_each_entry_safe(conn, tmp, &rxnet->idle_client_conns,
- cache_link) {
- if (conn->params.local == local) {
- trace_rxrpc_client(conn, -1, rxrpc_client_discard);
- list_move(&conn->cache_link, &graveyard);
- }
- }
- spin_unlock(&rxnet->client_conn_cache_lock);
- while (!list_empty(&graveyard)) {
- conn = list_entry(graveyard.next,
- struct rxrpc_connection, cache_link);
- list_del_init(&conn->cache_link);
- rxrpc_unbundle_conn(conn);
- rxrpc_put_connection(conn);
- }
- _leave(" [culled]");
- }
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