summaryrefslogtreecommitdiff
path: root/net/rxrpc/conn_client.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/rxrpc/conn_client.c')
-rw-r--r--net/rxrpc/conn_client.c372
1 files changed, 372 insertions, 0 deletions
diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
new file mode 100644
index 000000000..9e91f27b0
--- /dev/null
+++ b/net/rxrpc/conn_client.c
@@ -0,0 +1,372 @@
+/* Client connection-specific management code.
+ *
+ * Copyright (C) 2016 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 Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <linux/timer.h>
+#include "ar-internal.h"
+
+/*
+ * We use machine-unique IDs for our client connections.
+ */
+DEFINE_IDR(rxrpc_client_conn_ids);
+static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
+
+/*
+ * 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 is changed if this wraps.
+ *
+ * TODO: The IDR tree gets very expensive on memory if the connection IDs are
+ * widely scattered throughout the number space, so we shall need to retire
+ * connections that have, say, an ID more than four times the maximum number of
+ * client conns away from the current allocation point to try and keep the IDs
+ * concentrated. We will also need to retire connections from an old epoch.
+ */
+static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
+ gfp_t gfp)
+{
+ u32 epoch;
+ int id;
+
+ _enter("");
+
+ idr_preload(gfp);
+ spin_lock(&rxrpc_conn_id_lock);
+
+ epoch = rxrpc_epoch;
+
+ /* We could use idr_alloc_cyclic() here, but we really need to know
+ * when the thing wraps so that we can advance the epoch.
+ */
+ if (rxrpc_client_conn_ids.cur == 0)
+ rxrpc_client_conn_ids.cur = 1;
+ id = idr_alloc(&rxrpc_client_conn_ids, conn,
+ rxrpc_client_conn_ids.cur, 0x40000000, GFP_NOWAIT);
+ if (id < 0) {
+ if (id != -ENOSPC)
+ goto error;
+ id = idr_alloc(&rxrpc_client_conn_ids, conn,
+ 1, 0x40000000, GFP_NOWAIT);
+ if (id < 0)
+ goto error;
+ epoch++;
+ rxrpc_epoch = epoch;
+ }
+ rxrpc_client_conn_ids.cur = id + 1;
+
+ spin_unlock(&rxrpc_conn_id_lock);
+ idr_preload_end();
+
+ conn->proto.epoch = epoch;
+ conn->proto.cid = id << RXRPC_CIDSHIFT;
+ set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
+ _leave(" [CID %x:%x]", epoch, 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, atomic_read(&conn->usage));
+ }
+ BUG();
+ }
+
+ idr_destroy(&rxrpc_client_conn_ids);
+}
+
+/*
+ * Allocate a client connection. The caller must take care to clear any
+ * padding bytes in *cp.
+ */
+static struct rxrpc_connection *
+rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, 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->out_clientflag = RXRPC_CLIENT_INITIATED;
+ conn->state = RXRPC_CONN_CLIENT;
+
+ 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;
+
+ ret = conn->security->prime_packet_security(conn);
+ if (ret < 0)
+ goto error_2;
+
+ write_lock(&rxrpc_connection_lock);
+ list_add_tail(&conn->link, &rxrpc_connections);
+ write_unlock(&rxrpc_connection_lock);
+
+ /* We steal the caller's peer ref. */
+ cp->peer = NULL;
+ rxrpc_get_local(conn->params.local);
+ key_get(conn->params.key);
+
+ _leave(" = %p", conn);
+ return conn;
+
+error_2:
+ conn->security->clear(conn);
+error_1:
+ rxrpc_put_client_connection_id(conn);
+error_0:
+ kfree(conn);
+ _leave(" = %d", ret);
+ return ERR_PTR(ret);
+}
+
+/*
+ * find a connection for a call
+ * - called in process context with IRQs enabled
+ */
+int rxrpc_connect_call(struct rxrpc_call *call,
+ struct rxrpc_conn_parameters *cp,
+ struct sockaddr_rxrpc *srx,
+ gfp_t gfp)
+{
+ struct rxrpc_connection *conn, *candidate = NULL;
+ struct rxrpc_local *local = cp->local;
+ struct rb_node *p, **pp, *parent;
+ long diff;
+ int chan;
+
+ DECLARE_WAITQUEUE(myself, current);
+
+ _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
+
+ cp->peer = rxrpc_lookup_peer(cp->local, srx, gfp);
+ if (!cp->peer)
+ return -ENOMEM;
+
+ if (!cp->exclusive) {
+ /* Search for a existing client connection unless this is going
+ * to be a connection that's used exclusively for a single call.
+ */
+ _debug("search 1");
+ spin_lock(&local->client_conns_lock);
+ p = local->client_conns.rb_node;
+ while (p) {
+ conn = rb_entry(p, struct rxrpc_connection, client_node);
+
+#define cmp(X) ((long)conn->params.X - (long)cp->X)
+ diff = (cmp(peer) ?:
+ cmp(key) ?:
+ cmp(security_level));
+ if (diff < 0)
+ p = p->rb_left;
+ else if (diff > 0)
+ p = p->rb_right;
+ else
+ goto found_extant_conn;
+ }
+ spin_unlock(&local->client_conns_lock);
+ }
+
+ /* We didn't find a connection or we want an exclusive one. */
+ _debug("get new conn");
+ candidate = rxrpc_alloc_client_connection(cp, gfp);
+ if (!candidate) {
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+ }
+
+ if (cp->exclusive) {
+ /* Assign the call on an exclusive connection to channel 0 and
+ * don't add the connection to the endpoint's shareable conn
+ * lookup tree.
+ */
+ _debug("exclusive chan 0");
+ conn = candidate;
+ atomic_set(&conn->avail_chans, RXRPC_MAXCALLS - 1);
+ spin_lock(&conn->channel_lock);
+ chan = 0;
+ goto found_channel;
+ }
+
+ /* We need to redo the search before attempting to add a new connection
+ * lest we race with someone else adding a conflicting instance.
+ */
+ _debug("search 2");
+ spin_lock(&local->client_conns_lock);
+
+ pp = &local->client_conns.rb_node;
+ parent = NULL;
+ while (*pp) {
+ parent = *pp;
+ conn = rb_entry(parent, struct rxrpc_connection, client_node);
+
+ diff = (cmp(peer) ?:
+ cmp(key) ?:
+ cmp(security_level));
+ if (diff < 0)
+ pp = &(*pp)->rb_left;
+ else if (diff > 0)
+ pp = &(*pp)->rb_right;
+ else
+ goto found_extant_conn;
+ }
+
+ /* The second search also failed; simply add the new connection with
+ * the new call in channel 0. Note that we need to take the channel
+ * lock before dropping the client conn lock.
+ */
+ _debug("new conn");
+ set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
+ rb_link_node(&candidate->client_node, parent, pp);
+ rb_insert_color(&candidate->client_node, &local->client_conns);
+attached:
+ conn = candidate;
+ candidate = NULL;
+
+ atomic_set(&conn->avail_chans, RXRPC_MAXCALLS - 1);
+ spin_lock(&conn->channel_lock);
+ spin_unlock(&local->client_conns_lock);
+ chan = 0;
+
+found_channel:
+ _debug("found chan");
+ call->conn = conn;
+ call->channel = chan;
+ call->epoch = conn->proto.epoch;
+ call->cid = conn->proto.cid | chan;
+ call->call_id = ++conn->channels[chan].call_counter;
+ conn->channels[chan].call_id = call->call_id;
+ rcu_assign_pointer(conn->channels[chan].call, call);
+
+ _net("CONNECT call %d on conn %d", call->debug_id, conn->debug_id);
+
+ spin_unlock(&conn->channel_lock);
+ rxrpc_put_peer(cp->peer);
+ cp->peer = NULL;
+ _leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
+ return 0;
+
+ /* We found a potentially suitable connection already in existence. If
+ * we can reuse it (ie. its usage count hasn't been reduced to 0 by the
+ * reaper), discard any candidate we may have allocated, and try to get
+ * a channel on this one, otherwise we have to replace it.
+ */
+found_extant_conn:
+ _debug("found conn");
+ if (!rxrpc_get_connection_maybe(conn)) {
+ set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
+ rb_replace_node(&conn->client_node,
+ &candidate->client_node,
+ &local->client_conns);
+ clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags);
+ goto attached;
+ }
+
+ spin_unlock(&local->client_conns_lock);
+
+ rxrpc_put_connection(candidate);
+
+ if (!atomic_add_unless(&conn->avail_chans, -1, 0)) {
+ if (!gfpflags_allow_blocking(gfp)) {
+ rxrpc_put_connection(conn);
+ _leave(" = -EAGAIN");
+ return -EAGAIN;
+ }
+
+ add_wait_queue(&conn->channel_wq, &myself);
+ for (;;) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (atomic_add_unless(&conn->avail_chans, -1, 0))
+ break;
+ if (signal_pending(current))
+ goto interrupted;
+ schedule();
+ }
+ remove_wait_queue(&conn->channel_wq, &myself);
+ __set_current_state(TASK_RUNNING);
+ }
+
+ /* The connection allegedly now has a free channel and we can now
+ * attach the call to it.
+ */
+ spin_lock(&conn->channel_lock);
+
+ for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
+ if (!conn->channels[chan].call)
+ goto found_channel;
+ BUG();
+
+interrupted:
+ remove_wait_queue(&conn->channel_wq, &myself);
+ __set_current_state(TASK_RUNNING);
+ rxrpc_put_connection(conn);
+ rxrpc_put_peer(cp->peer);
+ cp->peer = NULL;
+ _leave(" = -ERESTARTSYS");
+ return -ERESTARTSYS;
+}
+
+/*
+ * Remove a client connection from the local endpoint's tree, thereby removing
+ * it as a target for reuse for new client calls.
+ */
+void rxrpc_unpublish_client_conn(struct rxrpc_connection *conn)
+{
+ struct rxrpc_local *local = conn->params.local;
+
+ spin_lock(&local->client_conns_lock);
+ if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags))
+ rb_erase(&conn->client_node, &local->client_conns);
+ spin_unlock(&local->client_conns_lock);
+
+ rxrpc_put_client_connection_id(conn);
+}