dbbea6713d
Quite a while ago I started this book. The required kernel-doc patches have since gone into the tree so it is now possible to build the book in mainline. The actual documentation is still rather incomplete and not all things are linked into the book, but this enables us to edit the documentation collaboratively, hopefully driver authors can add documentation based on their experience with mac80211. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
369 lines
8.6 KiB
C
369 lines
8.6 KiB
C
/*
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* Copyright 2002-2005, Instant802 Networks, Inc.
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* Copyright 2005-2006, Devicescape Software, Inc.
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* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
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* Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/if_ether.h>
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#include <linux/etherdevice.h>
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#include <linux/list.h>
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#include <linux/rcupdate.h>
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#include <linux/rtnetlink.h>
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#include <net/mac80211.h>
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#include "ieee80211_i.h"
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#include "debugfs_key.h"
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#include "aes_ccm.h"
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/**
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* DOC: Key handling basics
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*
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* Key handling in mac80211 is done based on per-interface (sub_if_data)
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* keys and per-station keys. Since each station belongs to an interface,
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* each station key also belongs to that interface.
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*
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* Hardware acceleration is done on a best-effort basis, for each key
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* that is eligible the hardware is asked to enable that key but if
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* it cannot do that they key is simply kept for software encryption.
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* There is currently no way of knowing this except by looking into
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* debugfs.
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*
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* All operations here are called under RTNL so no extra locking is
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* required.
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*
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* NOTE: This code requires that sta info *destruction* is done under
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* RTNL, otherwise it can try to access already freed STA structs
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* when a STA key is being freed.
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*/
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static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
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static const u8 zero_addr[ETH_ALEN];
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static const u8 *get_mac_for_key(struct ieee80211_key *key)
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{
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const u8 *addr = bcast_addr;
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/*
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* If we're an AP we won't ever receive frames with a non-WEP
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* group key so we tell the driver that by using the zero MAC
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* address to indicate a transmit-only key.
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*/
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if (key->conf.alg != ALG_WEP &&
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(key->sdata->vif.type == IEEE80211_IF_TYPE_AP ||
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key->sdata->vif.type == IEEE80211_IF_TYPE_VLAN))
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addr = zero_addr;
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if (key->sta)
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addr = key->sta->addr;
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return addr;
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}
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static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
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{
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const u8 *addr;
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int ret;
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DECLARE_MAC_BUF(mac);
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if (!key->local->ops->set_key)
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return;
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addr = get_mac_for_key(key);
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ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
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key->sdata->dev->dev_addr, addr,
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&key->conf);
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if (!ret)
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key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
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if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
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printk(KERN_ERR "mac80211-%s: failed to set key "
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"(%d, %s) to hardware (%d)\n",
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wiphy_name(key->local->hw.wiphy),
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key->conf.keyidx, print_mac(mac, addr), ret);
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}
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static void ieee80211_key_mark_hw_accel_off(struct ieee80211_key *key)
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{
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if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
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key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
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key->flags |= KEY_FLAG_REMOVE_FROM_HARDWARE;
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}
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}
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static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
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{
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const u8 *addr;
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int ret;
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DECLARE_MAC_BUF(mac);
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if (!key || !key->local->ops->set_key)
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return;
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if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
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!(key->flags & KEY_FLAG_REMOVE_FROM_HARDWARE))
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return;
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addr = get_mac_for_key(key);
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ret = key->local->ops->set_key(local_to_hw(key->local), DISABLE_KEY,
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key->sdata->dev->dev_addr, addr,
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&key->conf);
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if (ret)
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printk(KERN_ERR "mac80211-%s: failed to remove key "
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"(%d, %s) from hardware (%d)\n",
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wiphy_name(key->local->hw.wiphy),
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key->conf.keyidx, print_mac(mac, addr), ret);
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key->flags &= ~(KEY_FLAG_UPLOADED_TO_HARDWARE |
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KEY_FLAG_REMOVE_FROM_HARDWARE);
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}
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struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
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int idx,
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size_t key_len,
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const u8 *key_data)
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{
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struct ieee80211_key *key;
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BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS);
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key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
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if (!key)
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return NULL;
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/*
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* Default to software encryption; we'll later upload the
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* key to the hardware if possible.
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*/
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key->conf.flags = 0;
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key->flags = 0;
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key->conf.alg = alg;
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key->conf.keyidx = idx;
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key->conf.keylen = key_len;
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memcpy(key->conf.key, key_data, key_len);
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INIT_LIST_HEAD(&key->list);
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if (alg == ALG_CCMP) {
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/*
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* Initialize AES key state here as an optimization so that
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* it does not need to be initialized for every packet.
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*/
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key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
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if (!key->u.ccmp.tfm) {
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ieee80211_key_free(key);
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return NULL;
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}
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}
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return key;
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}
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static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
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struct sta_info *sta,
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struct ieee80211_key *key,
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struct ieee80211_key *new)
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{
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int idx, defkey;
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if (sta) {
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rcu_assign_pointer(sta->key, new);
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} else {
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WARN_ON(new && key && new->conf.keyidx != key->conf.keyidx);
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if (key)
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idx = key->conf.keyidx;
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else
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idx = new->conf.keyidx;
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defkey = key && sdata->default_key == key;
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if (defkey && !new)
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ieee80211_set_default_key(sdata, -1);
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rcu_assign_pointer(sdata->keys[idx], new);
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if (new)
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list_add(&new->list, &sdata->key_list);
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if (defkey && new)
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ieee80211_set_default_key(sdata, new->conf.keyidx);
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}
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if (key) {
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ieee80211_key_mark_hw_accel_off(key);
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/*
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* We'll use an empty list to indicate that the key
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* has already been removed.
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*/
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list_del_init(&key->list);
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}
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}
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void ieee80211_key_link(struct ieee80211_key *key,
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struct ieee80211_sub_if_data *sdata,
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struct sta_info *sta)
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{
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struct ieee80211_key *old_key;
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int idx;
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ASSERT_RTNL();
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might_sleep();
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BUG_ON(!sdata);
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BUG_ON(!key);
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idx = key->conf.keyidx;
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key->local = sdata->local;
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key->sdata = sdata;
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key->sta = sta;
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ieee80211_debugfs_key_add(key->local, key);
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if (sta) {
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ieee80211_debugfs_key_sta_link(key, sta);
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/*
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* some hardware cannot handle TKIP with QoS, so
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* we indicate whether QoS could be in use.
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*/
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if (sta->flags & WLAN_STA_WME)
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key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
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} else {
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if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
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struct sta_info *ap;
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rcu_read_lock();
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/* same here, the AP could be using QoS */
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ap = sta_info_get(key->local, key->sdata->u.sta.bssid);
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if (ap) {
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if (ap->flags & WLAN_STA_WME)
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key->conf.flags |=
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IEEE80211_KEY_FLAG_WMM_STA;
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}
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rcu_read_unlock();
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}
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}
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if (sta)
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old_key = sta->key;
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else
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old_key = sdata->keys[idx];
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__ieee80211_key_replace(sdata, sta, old_key, key);
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if (old_key) {
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synchronize_rcu();
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ieee80211_key_free(old_key);
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}
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if (netif_running(sdata->dev))
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ieee80211_key_enable_hw_accel(key);
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}
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void ieee80211_key_free(struct ieee80211_key *key)
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{
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ASSERT_RTNL();
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might_sleep();
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if (!key)
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return;
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if (key->sdata) {
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/*
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* Replace key with nothingness.
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*
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* Because other code may have key reference (RCU protected)
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* right now, we then wait for a grace period before freeing
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* it.
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* An empty list indicates it was never added to the key list
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* or has been removed already. It may, however, still be in
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* hardware for acceleration.
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*/
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if (!list_empty(&key->list))
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__ieee80211_key_replace(key->sdata, key->sta,
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key, NULL);
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/*
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* Do NOT remove this without looking at sta_info_destroy()
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*/
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synchronize_rcu();
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/*
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* Remove from hwaccel if appropriate, this will
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* only happen when the key is actually unlinked,
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* it will already be done when the key was replaced.
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*/
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ieee80211_key_disable_hw_accel(key);
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}
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if (key->conf.alg == ALG_CCMP)
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ieee80211_aes_key_free(key->u.ccmp.tfm);
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ieee80211_debugfs_key_remove(key);
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kfree(key);
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}
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void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
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{
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struct ieee80211_key *key = NULL;
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if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
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key = sdata->keys[idx];
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if (sdata->default_key != key) {
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ieee80211_debugfs_key_remove_default(sdata);
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rcu_assign_pointer(sdata->default_key, key);
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if (sdata->default_key)
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ieee80211_debugfs_key_add_default(sdata);
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}
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}
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void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_key *key, *tmp;
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LIST_HEAD(tmp_list);
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ASSERT_RTNL();
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might_sleep();
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list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
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ieee80211_key_free(key);
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}
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void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_key *key;
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ASSERT_RTNL();
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might_sleep();
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if (WARN_ON(!netif_running(sdata->dev)))
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return;
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list_for_each_entry(key, &sdata->key_list, list)
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ieee80211_key_enable_hw_accel(key);
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}
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void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_key *key;
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ASSERT_RTNL();
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might_sleep();
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list_for_each_entry(key, &sdata->key_list, list)
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ieee80211_key_disable_hw_accel(key);
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}
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