146 lines
4.4 KiB
C
146 lines
4.4 KiB
C
/*
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* Linux WiMAX
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* Mappping of generic netlink family IDs to net devices
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*
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*
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* Copyright (C) 2005-2006 Intel Corporation <linux-wimax@intel.com>
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* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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*
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* We assign a single generic netlink family ID to each device (to
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* simplify lookup).
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*
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* We need a way to map family ID to a wimax_dev pointer.
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*
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* The idea is to use a very simple lookup. Using a netlink attribute
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* with (for example) the interface name implies a heavier search over
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* all the network devices; seemed kind of a waste given that we know
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* we are looking for a WiMAX device and that most systems will have
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* just a single WiMAX adapter.
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*
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* We put all the WiMAX devices in the system in a linked list and
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* match the generic link family ID against the list.
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*
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* By using a linked list, the case of a single adapter in the system
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* becomes (almost) no overhead, while still working for many more. If
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* it ever goes beyond two, I'll be surprised.
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*/
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#include <linux/device.h>
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#include <net/genetlink.h>
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#include <linux/netdevice.h>
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#include <linux/list.h>
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#include <linux/wimax.h>
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#include "wimax-internal.h"
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#define D_SUBMODULE id_table
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#include "debug-levels.h"
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static DEFINE_SPINLOCK(wimax_id_table_lock);
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static struct list_head wimax_id_table = LIST_HEAD_INIT(wimax_id_table);
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/*
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* wimax_id_table_add - add a gennetlink familiy ID / wimax_dev mapping
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*
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* @wimax_dev: WiMAX device descriptor to associate to the Generic
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* Netlink family ID.
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*
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* Look for an empty spot in the ID table; if none found, double the
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* table's size and get the first spot.
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*/
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void wimax_id_table_add(struct wimax_dev *wimax_dev)
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{
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d_fnstart(3, NULL, "(wimax_dev %p)\n", wimax_dev);
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spin_lock(&wimax_id_table_lock);
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list_add(&wimax_dev->id_table_node, &wimax_id_table);
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spin_unlock(&wimax_id_table_lock);
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d_fnend(3, NULL, "(wimax_dev %p)\n", wimax_dev);
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}
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/*
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* wimax_get_netdev_by_info - lookup a wimax_dev from the gennetlink info
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*
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* The generic netlink family ID has been filled out in the
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* nlmsghdr->nlmsg_type field, so we pull it from there, look it up in
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* the mapping table and reference the wimax_dev.
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*
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* When done, the reference should be dropped with
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* 'dev_put(wimax_dev->net_dev)'.
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*/
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struct wimax_dev *wimax_dev_get_by_genl_info(
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struct genl_info *info, int ifindex)
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{
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struct wimax_dev *wimax_dev = NULL;
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d_fnstart(3, NULL, "(info %p ifindex %d)\n", info, ifindex);
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spin_lock(&wimax_id_table_lock);
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list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) {
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if (wimax_dev->net_dev->ifindex == ifindex) {
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dev_hold(wimax_dev->net_dev);
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goto found;
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}
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}
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wimax_dev = NULL;
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d_printf(1, NULL, "wimax: no devices found with ifindex %d\n",
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ifindex);
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found:
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spin_unlock(&wimax_id_table_lock);
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d_fnend(3, NULL, "(info %p ifindex %d) = %p\n",
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info, ifindex, wimax_dev);
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return wimax_dev;
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}
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/*
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* wimax_id_table_rm - Remove a gennetlink familiy ID / wimax_dev mapping
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*
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* @id: family ID to remove from the table
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*/
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void wimax_id_table_rm(struct wimax_dev *wimax_dev)
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{
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spin_lock(&wimax_id_table_lock);
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list_del_init(&wimax_dev->id_table_node);
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spin_unlock(&wimax_id_table_lock);
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}
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/*
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* Release the gennetlink family id / mapping table
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*
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* On debug, verify that the table is empty upon removal. We want the
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* code always compiled, to ensure it doesn't bit rot. It will be
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* compiled out if CONFIG_BUG is disabled.
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*/
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void wimax_id_table_release(void)
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{
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struct wimax_dev *wimax_dev;
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#ifndef CONFIG_BUG
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return;
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#endif
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spin_lock(&wimax_id_table_lock);
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list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) {
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printk(KERN_ERR "BUG: %s wimax_dev %p ifindex %d not cleared\n",
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__func__, wimax_dev, wimax_dev->net_dev->ifindex);
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WARN_ON(1);
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}
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spin_unlock(&wimax_id_table_lock);
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}
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