kdbus: add code for buses, domains and endpoints

Add the logic to handle the following entities:

Domain:
  A domain is an unamed object containing a number of buses. A
  domain is automatically created when an instance of kdbusfs
  is mounted, and destroyed when it is unmounted.
  Every domain offers its own 'control' device node to create
  buses. Domains are isolated from each other.

Bus:
  A bus is a named object inside a domain. Clients exchange messages
  over a bus. Multiple buses themselves have no connection to each
  other; messages can only be exchanged on the same bus. The default
  entry point to a bus, where clients establish the connection to, is
  the "bus" device node /sys/fs/kdbus/<bus name>/bus.  Common operating
  system setups create one "system bus" per system, and one "user
  bus" for every logged-in user. Applications or services may create
  their own private named buses.

Endpoint:
  An endpoint provides the device node to talk to a bus. Opening an
  endpoint creates a new connection to the bus to which the endpoint
  belongs. Every bus has a default endpoint called "bus". A bus can
  optionally offer additional endpoints with custom names to provide
  a restricted access to the same bus. Custom endpoints carry
  additional policy which can be used to give sandboxed processes
  only a locked-down, limited, filtered access to the same bus.

See kdbus(7), kdbus.bus(7), kdbus.endpoint(7) and kdbus.fs(7)
for more details.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 101 insertions, 0 deletions

diff --git a/ipc/kdbus/bus.h b/ipc/kdbus/bus.h
new file mode 100644
index 00000000000..5bea5ef768f
--- /dev/null
+++ b/ipc/kdbus/bus.h
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2013-2015 Kay Sievers
+ * Copyright (C) 2013-2015 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (C) 2013-2015 Daniel Mack <daniel@zonque.org>
+ * Copyright (C) 2013-2015 David Herrmann <dh.herrmann@gmail.com>
+ * Copyright (C) 2013-2015 Linux Foundation
+ * Copyright (C) 2014-2015 Djalal Harouni <tixxdz@opendz.org>
+ *
+ * kdbus is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ */
+
+#ifndef __KDBUS_BUS_H
+#define __KDBUS_BUS_H
+
+#include <linux/hashtable.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/spinlock.h>
+#include <uapi/linux/kdbus.h>
+
+#include "metadata.h"
+#include "names.h"
+#include "node.h"
+#include "policy.h"
+
+struct kdbus_conn;
+struct kdbus_domain;
+struct kdbus_kmsg;
+struct kdbus_user;
+
+/**
+ * struct kdbus_bus - bus in a domain
+ * @node:		kdbus_node
+ * @id:			ID of this bus in the domain
+ * @bus_flags:		Simple pass-through flags from userspace to userspace
+ * @attach_flags_req:	KDBUS_ATTACH_* flags required by connecting peers
+ * @attach_flags_owner:	KDBUS_ATTACH_* flags of bus creator that other
+ *			connections can see or query
+ * @id128:		Unique random 128 bit ID of this bus
+ * @bloom:		Bloom parameters
+ * @domain:		Domain of this bus
+ * @creator:		Creator of the bus
+ * @creator_meta:	Meta information about the bus creator
+ * @policy_db:		Policy database for this bus
+ * @name_registry:	Name registry of this bus
+ * @conn_rwlock:	Read/Write lock for all lists of child connections
+ * @conn_hash:		Map of connection IDs
+ * @monitors_list:	Connections that monitor this bus
+ * @notify_list:	List of pending kernel-generated messages
+ * @notify_lock:	Notification list lock
+ * @notify_flush_lock:	Notification flushing lock
+ */
+struct kdbus_bus {
+	struct kdbus_node node;
+
+	/* static */
+	u64 id;
+	u64 bus_flags;
+	u64 attach_flags_req;
+	u64 attach_flags_owner;
+	u8 id128[16];
+	struct kdbus_bloom_parameter bloom;
+	struct kdbus_domain *domain;
+	struct kdbus_user *creator;
+	struct kdbus_meta_proc *creator_meta;
+
+	/* protected by own locks */
+	struct kdbus_policy_db policy_db;
+	struct kdbus_name_registry *name_registry;
+
+	/* protected by conn_rwlock */
+	struct rw_semaphore conn_rwlock;
+	DECLARE_HASHTABLE(conn_hash, 8);
+	struct list_head monitors_list;
+
+	/* protected by notify_lock */
+	struct list_head notify_list;
+	spinlock_t notify_lock;
+	struct mutex notify_flush_lock;
+};
+
+struct kdbus_bus *kdbus_bus_ref(struct kdbus_bus *bus);
+struct kdbus_bus *kdbus_bus_unref(struct kdbus_bus *bus);
+
+struct kdbus_conn *kdbus_bus_find_conn_by_id(struct kdbus_bus *bus, u64 id);
+void kdbus_bus_broadcast(struct kdbus_bus *bus,
+			 struct kdbus_conn *conn_src,
+			 struct kdbus_kmsg *kmsg);
+void kdbus_bus_eavesdrop(struct kdbus_bus *bus,
+			 struct kdbus_conn *conn_src,
+			 struct kdbus_kmsg *kmsg);
+
+struct kdbus_bus *kdbus_cmd_bus_make(struct kdbus_domain *domain,
+				     void __user *argp);
+int kdbus_cmd_bus_creator_info(struct kdbus_conn *conn, void __user *argp);
+
+#endif