1// SPDX-License-Identifier: GPL-2.0
2/*
3 * IEEE 802.15.4 PAN management
4 *
5 * Copyright (C) 2023 Qorvo US, Inc
6 * Authors:
7 *   - David Girault <david.girault@qorvo.com>
8 *   - Miquel Raynal <miquel.raynal@bootlin.com>
9 */
10
11#include <linux/kernel.h>
12#include <net/cfg802154.h>
13#include <net/af_ieee802154.h>
14
15/* Checks whether a device address matches one from the PAN list.
16 * This helper is meant to be used only during PAN management, when we expect
17 * extended addresses to be used.
18 */
19static bool cfg802154_pan_device_is_matching(struct ieee802154_pan_device *pan_dev,
20					     struct ieee802154_addr *ext_dev)
21{
22	if (!pan_dev || !ext_dev)
23		return false;
24
25	if (ext_dev->mode == IEEE802154_ADDR_SHORT)
26		return false;
27
28	return pan_dev->extended_addr == ext_dev->extended_addr;
29}
30
31bool cfg802154_device_is_associated(struct wpan_dev *wpan_dev)
32{
33	bool is_assoc;
34
35	mutex_lock(&wpan_dev->association_lock);
36	is_assoc = !list_empty(&wpan_dev->children) || wpan_dev->parent;
37	mutex_unlock(&wpan_dev->association_lock);
38
39	return is_assoc;
40}
41
42bool cfg802154_device_is_parent(struct wpan_dev *wpan_dev,
43				struct ieee802154_addr *target)
44{
45	lockdep_assert_held(&wpan_dev->association_lock);
46
47	return cfg802154_pan_device_is_matching(wpan_dev->parent, target);
48}
49EXPORT_SYMBOL_GPL(cfg802154_device_is_parent);
50
51struct ieee802154_pan_device *
52cfg802154_device_is_child(struct wpan_dev *wpan_dev,
53			  struct ieee802154_addr *target)
54{
55	struct ieee802154_pan_device *child;
56
57	lockdep_assert_held(&wpan_dev->association_lock);
58
59	list_for_each_entry(child, &wpan_dev->children, node)
60		if (cfg802154_pan_device_is_matching(child, target))
61			return child;
62
63	return NULL;
64}
65EXPORT_SYMBOL_GPL(cfg802154_device_is_child);
66
67__le16 cfg802154_get_free_short_addr(struct wpan_dev *wpan_dev)
68{
69	struct ieee802154_pan_device *child;
70	__le16 addr;
71
72	lockdep_assert_held(&wpan_dev->association_lock);
73
74	do {
75		get_random_bytes(&addr, 2);
76		if (addr == cpu_to_le16(IEEE802154_ADDR_SHORT_BROADCAST) ||
77		    addr == cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC))
78			continue;
79
80		if (wpan_dev->short_addr == addr)
81			continue;
82
83		if (wpan_dev->parent && wpan_dev->parent->short_addr == addr)
84			continue;
85
86		list_for_each_entry(child, &wpan_dev->children, node)
87			if (child->short_addr == addr)
88				continue;
89
90		break;
91	} while (1);
92
93	return addr;
94}
95EXPORT_SYMBOL_GPL(cfg802154_get_free_short_addr);
96
97unsigned int cfg802154_set_max_associations(struct wpan_dev *wpan_dev,
98					    unsigned int max)
99{
100	unsigned int old_max;
101
102	lockdep_assert_held(&wpan_dev->association_lock);
103
104	old_max = wpan_dev->max_associations;
105	wpan_dev->max_associations = max;
106
107	return old_max;
108}
109EXPORT_SYMBOL_GPL(cfg802154_set_max_associations);
110