rxrpc: Split client connection code out into its own file

Split the client-specific connection code out into its own file.  It will
behave somewhat differently from the service-specific connection code, so
it makes sense to separate them.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 247 insertions, 1 deletions

diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index be437d5e90ce..9180164a51aa 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -33,7 +33,8 @@ static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
  * 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.
  */
-int rxrpc_get_client_connection_id(struct rxrpc_connection *conn, gfp_t gfp)
+static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
+					  gfp_t gfp)
 {
 	u32 epoch;
 	int id;
@@ -111,3 +112,248 @@ void rxrpc_destroy_client_conn_ids(void)
 
 	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->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, 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");
+	conn = candidate;
+	candidate = NULL;
+
+	rb_link_node(&conn->client_node, parent, pp);
+	rb_insert_color(&conn->client_node, &local->client_conns);
+
+	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 suitable connection already in existence.  Discard any
+	 * candidate we may have allocated, and try to get a channel on this
+	 * one.
+	 */
+found_extant_conn:
+	_debug("found conn");
+	rxrpc_get_connection(conn);
+	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;
+}