1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Linux WiMAX 4 * Mappping of generic netlink family IDs to net devices 5 * 6 * Copyright (C) 2005-2006 Intel Corporation <linux-wimax@intel.com> 7 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> 8 * 9 * We assign a single generic netlink family ID to each device (to 10 * simplify lookup). 11 * 12 * We need a way to map family ID to a wimax_dev pointer. 13 * 14 * The idea is to use a very simple lookup. Using a netlink attribute 15 * with (for example) the interface name implies a heavier search over 16 * all the network devices; seemed kind of a waste given that we know 17 * we are looking for a WiMAX device and that most systems will have 18 * just a single WiMAX adapter. 19 * 20 * We put all the WiMAX devices in the system in a linked list and 21 * match the generic link family ID against the list. 22 * 23 * By using a linked list, the case of a single adapter in the system 24 * becomes (almost) no overhead, while still working for many more. If 25 * it ever goes beyond two, I'll be surprised. 26 */ 27#include <linux/device.h> 28#include <net/genetlink.h> 29#include <linux/netdevice.h> 30#include <linux/list.h> 31#include <linux/wimax.h> 32#include "wimax-internal.h" 33 34 35#define D_SUBMODULE id_table 36#include "debug-levels.h" 37 38 39static DEFINE_SPINLOCK(wimax_id_table_lock); 40static struct list_head wimax_id_table = LIST_HEAD_INIT(wimax_id_table); 41 42 43/* 44 * wimax_id_table_add - add a gennetlink familiy ID / wimax_dev mapping 45 * 46 * @wimax_dev: WiMAX device descriptor to associate to the Generic 47 * Netlink family ID. 48 * 49 * Look for an empty spot in the ID table; if none found, double the 50 * table's size and get the first spot. 51 */ 52void wimax_id_table_add(struct wimax_dev *wimax_dev) 53{ 54 d_fnstart(3, NULL, "(wimax_dev %p)\n", wimax_dev); 55 spin_lock(&wimax_id_table_lock); 56 list_add(&wimax_dev->id_table_node, &wimax_id_table); 57 spin_unlock(&wimax_id_table_lock); 58 d_fnend(3, NULL, "(wimax_dev %p)\n", wimax_dev); 59} 60 61 62/* 63 * wimax_get_netdev_by_info - lookup a wimax_dev from the gennetlink info 64 * 65 * The generic netlink family ID has been filled out in the 66 * nlmsghdr->nlmsg_type field, so we pull it from there, look it up in 67 * the mapping table and reference the wimax_dev. 68 * 69 * When done, the reference should be dropped with 70 * 'dev_put(wimax_dev->net_dev)'. 71 */ 72struct wimax_dev *wimax_dev_get_by_genl_info( 73 struct genl_info *info, int ifindex) 74{ 75 struct wimax_dev *wimax_dev = NULL; 76 77 d_fnstart(3, NULL, "(info %p ifindex %d)\n", info, ifindex); 78 spin_lock(&wimax_id_table_lock); 79 list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) { 80 if (wimax_dev->net_dev->ifindex == ifindex) { 81 dev_hold(wimax_dev->net_dev); 82 goto found; 83 } 84 } 85 wimax_dev = NULL; 86 d_printf(1, NULL, "wimax: no devices found with ifindex %d\n", 87 ifindex); 88found: 89 spin_unlock(&wimax_id_table_lock); 90 d_fnend(3, NULL, "(info %p ifindex %d) = %p\n", 91 info, ifindex, wimax_dev); 92 return wimax_dev; 93} 94 95 96/* 97 * wimax_id_table_rm - Remove a gennetlink familiy ID / wimax_dev mapping 98 * 99 * @id: family ID to remove from the table 100 */ 101void wimax_id_table_rm(struct wimax_dev *wimax_dev) 102{ 103 spin_lock(&wimax_id_table_lock); 104 list_del_init(&wimax_dev->id_table_node); 105 spin_unlock(&wimax_id_table_lock); 106} 107 108 109/* 110 * Release the gennetlink family id / mapping table 111 * 112 * On debug, verify that the table is empty upon removal. We want the 113 * code always compiled, to ensure it doesn't bit rot. It will be 114 * compiled out if CONFIG_BUG is disabled. 115 */ 116void wimax_id_table_release(void) 117{ 118 struct wimax_dev *wimax_dev; 119 120#ifndef CONFIG_BUG 121 return; 122#endif 123 spin_lock(&wimax_id_table_lock); 124 list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) { 125 pr_err("BUG: %s wimax_dev %p ifindex %d not cleared\n", 126 __func__, wimax_dev, wimax_dev->net_dev->ifindex); 127 WARN_ON(1); 128 } 129 spin_unlock(&wimax_id_table_lock); 130} 131