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15530dfd IPG |
1 | /* |
2 | * Linux WiMAX | |
3 | * Mappping of generic netlink family IDs to net devices | |
4 | * | |
5 | * | |
6 | * Copyright (C) 2005-2006 Intel Corporation <linux-wimax@intel.com> | |
7 | * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License version | |
11 | * 2 as published by the Free Software Foundation. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
21 | * 02110-1301, USA. | |
22 | * | |
23 | * | |
24 | * We assign a single generic netlink family ID to each device (to | |
25 | * simplify lookup). | |
26 | * | |
27 | * We need a way to map family ID to a wimax_dev pointer. | |
28 | * | |
29 | * The idea is to use a very simple lookup. Using a netlink attribute | |
30 | * with (for example) the interface name implies a heavier search over | |
31 | * all the network devices; seemed kind of a waste given that we know | |
32 | * we are looking for a WiMAX device and that most systems will have | |
33 | * just a single WiMAX adapter. | |
34 | * | |
35 | * We put all the WiMAX devices in the system in a linked list and | |
36 | * match the generic link family ID against the list. | |
37 | * | |
38 | * By using a linked list, the case of a single adapter in the system | |
39 | * becomes (almost) no overhead, while still working for many more. If | |
40 | * it ever goes beyond two, I'll be surprised. | |
41 | */ | |
42 | #include <linux/device.h> | |
43 | #include <net/genetlink.h> | |
44 | #include <linux/netdevice.h> | |
45 | #include <linux/list.h> | |
46 | #include <linux/wimax.h> | |
47 | #include "wimax-internal.h" | |
48 | ||
49 | ||
50 | #define D_SUBMODULE id_table | |
51 | #include "debug-levels.h" | |
52 | ||
53 | ||
54 | static DEFINE_SPINLOCK(wimax_id_table_lock); | |
55 | static struct list_head wimax_id_table = LIST_HEAD_INIT(wimax_id_table); | |
56 | ||
57 | ||
58 | /* | |
59 | * wimax_id_table_add - add a gennetlink familiy ID / wimax_dev mapping | |
60 | * | |
61 | * @wimax_dev: WiMAX device descriptor to associate to the Generic | |
62 | * Netlink family ID. | |
63 | * | |
64 | * Look for an empty spot in the ID table; if none found, double the | |
65 | * table's size and get the first spot. | |
66 | */ | |
67 | void wimax_id_table_add(struct wimax_dev *wimax_dev) | |
68 | { | |
69 | d_fnstart(3, NULL, "(wimax_dev %p)\n", wimax_dev); | |
70 | spin_lock(&wimax_id_table_lock); | |
71 | list_add(&wimax_dev->id_table_node, &wimax_id_table); | |
72 | spin_unlock(&wimax_id_table_lock); | |
73 | d_fnend(3, NULL, "(wimax_dev %p)\n", wimax_dev); | |
74 | } | |
75 | ||
76 | ||
77 | /* | |
78 | * wimax_get_netdev_by_info - lookup a wimax_dev from the gennetlink info | |
79 | * | |
80 | * The generic netlink family ID has been filled out in the | |
81 | * nlmsghdr->nlmsg_type field, so we pull it from there, look it up in | |
82 | * the mapping table and reference the wimax_dev. | |
83 | * | |
84 | * When done, the reference should be dropped with | |
85 | * 'dev_put(wimax_dev->net_dev)'. | |
86 | */ | |
87 | struct wimax_dev *wimax_dev_get_by_genl_info( | |
88 | struct genl_info *info, int ifindex) | |
89 | { | |
90 | struct wimax_dev *wimax_dev = NULL; | |
91 | ||
92 | d_fnstart(3, NULL, "(info %p ifindex %d)\n", info, ifindex); | |
93 | spin_lock(&wimax_id_table_lock); | |
94 | list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) { | |
95 | if (wimax_dev->net_dev->ifindex == ifindex) { | |
96 | dev_hold(wimax_dev->net_dev); | |
97 | break; | |
98 | } | |
99 | } | |
100 | if (wimax_dev == NULL) | |
101 | d_printf(1, NULL, "wimax: no devices found with ifindex %d\n", | |
102 | ifindex); | |
103 | spin_unlock(&wimax_id_table_lock); | |
104 | d_fnend(3, NULL, "(info %p ifindex %d) = %p\n", | |
105 | info, ifindex, wimax_dev); | |
106 | return wimax_dev; | |
107 | } | |
108 | ||
109 | ||
110 | /* | |
111 | * wimax_id_table_rm - Remove a gennetlink familiy ID / wimax_dev mapping | |
112 | * | |
113 | * @id: family ID to remove from the table | |
114 | */ | |
115 | void wimax_id_table_rm(struct wimax_dev *wimax_dev) | |
116 | { | |
117 | spin_lock(&wimax_id_table_lock); | |
118 | list_del_init(&wimax_dev->id_table_node); | |
119 | spin_unlock(&wimax_id_table_lock); | |
120 | } | |
121 | ||
122 | ||
123 | /* | |
124 | * Release the gennetlink family id / mapping table | |
125 | * | |
d48e470f IPG |
126 | * On debug, verify that the table is empty upon removal. We want the |
127 | * code always compiled, to ensure it doesn't bit rot. It will be | |
128 | * compiled out if CONFIG_BUG is disabled. | |
15530dfd IPG |
129 | */ |
130 | void wimax_id_table_release(void) | |
131 | { | |
d48e470f IPG |
132 | struct wimax_dev *wimax_dev; |
133 | ||
15530dfd IPG |
134 | #ifndef CONFIG_BUG |
135 | return; | |
136 | #endif | |
15530dfd IPG |
137 | spin_lock(&wimax_id_table_lock); |
138 | list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) { | |
139 | printk(KERN_ERR "BUG: %s wimax_dev %p ifindex %d not cleared\n", | |
140 | __func__, wimax_dev, wimax_dev->net_dev->ifindex); | |
141 | WARN_ON(1); | |
142 | } | |
143 | spin_unlock(&wimax_id_table_lock); | |
144 | } |