linux/net/mac80211/wme.c
Johannes Berg d0709a6518 mac80211: RCU-ify STA info structure access
This makes access to the STA hash table/list use RCU to protect
against freeing of items. However, it's not a true RCU, the
copy step is missing: whenever somebody changes a STA item it
is simply updated. This is an existing race condition that is
now somewhat understandable.

This patch also fixes the race key freeing vs. STA destruction
by making sure that sta_info_destroy() is always called under
RTNL and frees the key.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-03-06 15:30:46 -05:00

727 lines
18 KiB
C

/*
* Copyright 2004, Instant802 Networks, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/types.h>
#include <net/ip.h>
#include <net/pkt_sched.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "wme.h"
/* maximum number of hardware queues we support. */
#define TC_80211_MAX_QUEUES 16
const int ieee802_1d_to_ac[8] = { 2, 3, 3, 2, 1, 1, 0, 0 };
struct ieee80211_sched_data
{
unsigned long qdisc_pool[BITS_TO_LONGS(TC_80211_MAX_QUEUES)];
struct tcf_proto *filter_list;
struct Qdisc *queues[TC_80211_MAX_QUEUES];
struct sk_buff_head requeued[TC_80211_MAX_QUEUES];
};
static const char llc_ip_hdr[8] = {0xAA, 0xAA, 0x3, 0, 0, 0, 0x08, 0};
/* given a data frame determine the 802.1p/1d tag to use */
static inline unsigned classify_1d(struct sk_buff *skb, struct Qdisc *qd)
{
struct iphdr *ip;
int dscp;
int offset;
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct tcf_result res = { -1, 0 };
/* if there is a user set filter list, call out to that */
if (q->filter_list) {
tc_classify(skb, q->filter_list, &res);
if (res.class != -1)
return res.class;
}
/* skb->priority values from 256->263 are magic values to
* directly indicate a specific 802.1d priority.
* This is used to allow 802.1d priority to be passed directly in
* from VLAN tags, etc. */
if (skb->priority >= 256 && skb->priority <= 263)
return skb->priority - 256;
/* check there is a valid IP header present */
offset = ieee80211_get_hdrlen_from_skb(skb);
if (skb->len < offset + sizeof(llc_ip_hdr) + sizeof(*ip) ||
memcmp(skb->data + offset, llc_ip_hdr, sizeof(llc_ip_hdr)))
return 0;
ip = (struct iphdr *) (skb->data + offset + sizeof(llc_ip_hdr));
dscp = ip->tos & 0xfc;
if (dscp & 0x1c)
return 0;
return dscp >> 5;
}
static inline int wme_downgrade_ac(struct sk_buff *skb)
{
switch (skb->priority) {
case 6:
case 7:
skb->priority = 5; /* VO -> VI */
return 0;
case 4:
case 5:
skb->priority = 3; /* VI -> BE */
return 0;
case 0:
case 3:
skb->priority = 2; /* BE -> BK */
return 0;
default:
return -1;
}
}
/* positive return value indicates which queue to use
* negative return value indicates to drop the frame */
static inline int classify80211(struct sk_buff *skb, struct Qdisc *qd)
{
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
unsigned short fc = le16_to_cpu(hdr->frame_control);
int qos;
/* see if frame is data or non data frame */
if (unlikely((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)) {
/* management frames go on AC_VO queue, but are sent
* without QoS control fields */
return IEEE80211_TX_QUEUE_DATA0;
}
if (0 /* injected */) {
/* use AC from radiotap */
}
/* is this a QoS frame? */
qos = fc & IEEE80211_STYPE_QOS_DATA;
if (!qos) {
skb->priority = 0; /* required for correct WPA/11i MIC */
return ieee802_1d_to_ac[skb->priority];
}
/* use the data classifier to determine what 802.1d tag the
* data frame has */
skb->priority = classify_1d(skb, qd);
/* in case we are a client verify acm is not set for this ac */
while (unlikely(local->wmm_acm & BIT(skb->priority))) {
if (wme_downgrade_ac(skb)) {
/* No AC with lower priority has acm=0, drop packet. */
return -1;
}
}
/* look up which queue to use for frames with this 1d tag */
return ieee802_1d_to_ac[skb->priority];
}
static int wme_qdiscop_enqueue(struct sk_buff *skb, struct Qdisc* qd)
{
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct ieee80211_tx_packet_data *pkt_data =
(struct ieee80211_tx_packet_data *) skb->cb;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
unsigned short fc = le16_to_cpu(hdr->frame_control);
struct Qdisc *qdisc;
int err, queue;
struct sta_info *sta;
u8 tid;
if (pkt_data->flags & IEEE80211_TXPD_REQUEUE) {
queue = pkt_data->queue;
rcu_read_lock();
sta = sta_info_get(local, hdr->addr1);
tid = skb->priority & QOS_CONTROL_TAG1D_MASK;
if (sta) {
int ampdu_queue = sta->tid_to_tx_q[tid];
if ((ampdu_queue < local->hw.queues) &&
test_bit(ampdu_queue, q->qdisc_pool)) {
queue = ampdu_queue;
pkt_data->flags |= IEEE80211_TXPD_AMPDU;
} else {
pkt_data->flags &= ~IEEE80211_TXPD_AMPDU;
}
}
rcu_read_unlock();
skb_queue_tail(&q->requeued[queue], skb);
qd->q.qlen++;
return 0;
}
queue = classify80211(skb, qd);
/* now we know the 1d priority, fill in the QoS header if there is one
*/
if (WLAN_FC_IS_QOS_DATA(fc)) {
u8 *p = skb->data + ieee80211_get_hdrlen(fc) - 2;
u8 ack_policy = 0;
tid = skb->priority & QOS_CONTROL_TAG1D_MASK;
if (local->wifi_wme_noack_test)
ack_policy |= QOS_CONTROL_ACK_POLICY_NOACK <<
QOS_CONTROL_ACK_POLICY_SHIFT;
/* qos header is 2 bytes, second reserved */
*p = ack_policy | tid;
p++;
*p = 0;
rcu_read_lock();
sta = sta_info_get(local, hdr->addr1);
if (sta) {
int ampdu_queue = sta->tid_to_tx_q[tid];
if ((ampdu_queue < local->hw.queues) &&
test_bit(ampdu_queue, q->qdisc_pool)) {
queue = ampdu_queue;
pkt_data->flags |= IEEE80211_TXPD_AMPDU;
} else {
pkt_data->flags &= ~IEEE80211_TXPD_AMPDU;
}
}
rcu_read_unlock();
}
if (unlikely(queue >= local->hw.queues)) {
#if 0
if (net_ratelimit()) {
printk(KERN_DEBUG "%s - queue=%d (hw does not "
"support) -> %d\n",
__func__, queue, local->hw.queues - 1);
}
#endif
queue = local->hw.queues - 1;
}
if (unlikely(queue < 0)) {
kfree_skb(skb);
err = NET_XMIT_DROP;
} else {
tid = skb->priority & QOS_CONTROL_TAG1D_MASK;
pkt_data->queue = (unsigned int) queue;
qdisc = q->queues[queue];
err = qdisc->enqueue(skb, qdisc);
if (err == NET_XMIT_SUCCESS) {
qd->q.qlen++;
qd->bstats.bytes += skb->len;
qd->bstats.packets++;
return NET_XMIT_SUCCESS;
}
}
qd->qstats.drops++;
return err;
}
/* TODO: clean up the cases where master_hard_start_xmit
* returns non 0 - it shouldn't ever do that. Once done we
* can remove this function */
static int wme_qdiscop_requeue(struct sk_buff *skb, struct Qdisc* qd)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct ieee80211_tx_packet_data *pkt_data =
(struct ieee80211_tx_packet_data *) skb->cb;
struct Qdisc *qdisc;
int err;
/* we recorded which queue to use earlier! */
qdisc = q->queues[pkt_data->queue];
if ((err = qdisc->ops->requeue(skb, qdisc)) == 0) {
qd->q.qlen++;
return 0;
}
qd->qstats.drops++;
return err;
}
static struct sk_buff *wme_qdiscop_dequeue(struct Qdisc* qd)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct net_device *dev = qd->dev;
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
struct sk_buff *skb;
struct Qdisc *qdisc;
int queue;
/* check all the h/w queues in numeric/priority order */
for (queue = 0; queue < hw->queues; queue++) {
/* see if there is room in this hardware queue */
if ((test_bit(IEEE80211_LINK_STATE_XOFF,
&local->state[queue])) ||
(test_bit(IEEE80211_LINK_STATE_PENDING,
&local->state[queue])) ||
(!test_bit(queue, q->qdisc_pool)))
continue;
/* there is space - try and get a frame */
skb = skb_dequeue(&q->requeued[queue]);
if (skb) {
qd->q.qlen--;
return skb;
}
qdisc = q->queues[queue];
skb = qdisc->dequeue(qdisc);
if (skb) {
qd->q.qlen--;
return skb;
}
}
/* returning a NULL here when all the h/w queues are full means we
* never need to call netif_stop_queue in the driver */
return NULL;
}
static void wme_qdiscop_reset(struct Qdisc* qd)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
int queue;
/* QUESTION: should we have some hardware flush functionality here? */
for (queue = 0; queue < hw->queues; queue++) {
skb_queue_purge(&q->requeued[queue]);
qdisc_reset(q->queues[queue]);
}
qd->q.qlen = 0;
}
static void wme_qdiscop_destroy(struct Qdisc* qd)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
int queue;
tcf_destroy_chain(q->filter_list);
q->filter_list = NULL;
for (queue=0; queue < hw->queues; queue++) {
skb_queue_purge(&q->requeued[queue]);
qdisc_destroy(q->queues[queue]);
q->queues[queue] = &noop_qdisc;
}
}
/* called whenever parameters are updated on existing qdisc */
static int wme_qdiscop_tune(struct Qdisc *qd, struct nlattr *opt)
{
/* struct ieee80211_sched_data *q = qdisc_priv(qd);
*/
/* check our options block is the right size */
/* copy any options to our local structure */
/* Ignore options block for now - always use static mapping
struct tc_ieee80211_qopt *qopt = nla_data(opt);
if (opt->nla_len < nla_attr_size(sizeof(*qopt)))
return -EINVAL;
memcpy(q->tag2queue, qopt->tag2queue, sizeof(qopt->tag2queue));
*/
return 0;
}
/* called during initial creation of qdisc on device */
static int wme_qdiscop_init(struct Qdisc *qd, struct nlattr *opt)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct net_device *dev = qd->dev;
struct ieee80211_local *local;
int queues;
int err = 0, i;
/* check that device is a mac80211 device */
if (!dev->ieee80211_ptr ||
dev->ieee80211_ptr->wiphy->privid != mac80211_wiphy_privid)
return -EINVAL;
/* check this device is an ieee80211 master type device */
if (dev->type != ARPHRD_IEEE80211)
return -EINVAL;
/* check that there is no qdisc currently attached to device
* this ensures that we will be the root qdisc. (I can't find a better
* way to test this explicitly) */
if (dev->qdisc_sleeping != &noop_qdisc)
return -EINVAL;
if (qd->flags & TCQ_F_INGRESS)
return -EINVAL;
local = wdev_priv(dev->ieee80211_ptr);
queues = local->hw.queues;
/* if options were passed in, set them */
if (opt) {
err = wme_qdiscop_tune(qd, opt);
}
/* create child queues */
for (i = 0; i < queues; i++) {
skb_queue_head_init(&q->requeued[i]);
q->queues[i] = qdisc_create_dflt(qd->dev, &pfifo_qdisc_ops,
qd->handle);
if (!q->queues[i]) {
q->queues[i] = &noop_qdisc;
printk(KERN_ERR "%s child qdisc %i creation failed", dev->name, i);
}
}
/* reserve all legacy QoS queues */
for (i = 0; i < min(IEEE80211_TX_QUEUE_DATA4, queues); i++)
set_bit(i, q->qdisc_pool);
return err;
}
static int wme_qdiscop_dump(struct Qdisc *qd, struct sk_buff *skb)
{
/* struct ieee80211_sched_data *q = qdisc_priv(qd);
unsigned char *p = skb->tail;
struct tc_ieee80211_qopt opt;
memcpy(&opt.tag2queue, q->tag2queue, TC_80211_MAX_TAG + 1);
NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
*/ return skb->len;
/*
nla_put_failure:
skb_trim(skb, p - skb->data);*/
return -1;
}
static int wme_classop_graft(struct Qdisc *qd, unsigned long arg,
struct Qdisc *new, struct Qdisc **old)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
unsigned long queue = arg - 1;
if (queue >= hw->queues)
return -EINVAL;
if (!new)
new = &noop_qdisc;
sch_tree_lock(qd);
*old = q->queues[queue];
q->queues[queue] = new;
qdisc_reset(*old);
sch_tree_unlock(qd);
return 0;
}
static struct Qdisc *
wme_classop_leaf(struct Qdisc *qd, unsigned long arg)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
unsigned long queue = arg - 1;
if (queue >= hw->queues)
return NULL;
return q->queues[queue];
}
static unsigned long wme_classop_get(struct Qdisc *qd, u32 classid)
{
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
unsigned long queue = TC_H_MIN(classid);
if (queue - 1 >= hw->queues)
return 0;
return queue;
}
static unsigned long wme_classop_bind(struct Qdisc *qd, unsigned long parent,
u32 classid)
{
return wme_classop_get(qd, classid);
}
static void wme_classop_put(struct Qdisc *q, unsigned long cl)
{
}
static int wme_classop_change(struct Qdisc *qd, u32 handle, u32 parent,
struct nlattr **tca, unsigned long *arg)
{
unsigned long cl = *arg;
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
if (cl - 1 > hw->queues)
return -ENOENT;
/* TODO: put code to program hardware queue parameters here,
* to allow programming from tc command line */
return 0;
}
/* we don't support deleting hardware queues
* when we add WMM-SA support - TSPECs may be deleted here */
static int wme_classop_delete(struct Qdisc *qd, unsigned long cl)
{
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
if (cl - 1 > hw->queues)
return -ENOENT;
return 0;
}
static int wme_classop_dump_class(struct Qdisc *qd, unsigned long cl,
struct sk_buff *skb, struct tcmsg *tcm)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
if (cl - 1 > hw->queues)
return -ENOENT;
tcm->tcm_handle = TC_H_MIN(cl);
tcm->tcm_parent = qd->handle;
tcm->tcm_info = q->queues[cl-1]->handle; /* do we need this? */
return 0;
}
static void wme_classop_walk(struct Qdisc *qd, struct qdisc_walker *arg)
{
struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
struct ieee80211_hw *hw = &local->hw;
int queue;
if (arg->stop)
return;
for (queue = 0; queue < hw->queues; queue++) {
if (arg->count < arg->skip) {
arg->count++;
continue;
}
/* we should return classids for our internal queues here
* as well as the external ones */
if (arg->fn(qd, queue+1, arg) < 0) {
arg->stop = 1;
break;
}
arg->count++;
}
}
static struct tcf_proto ** wme_classop_find_tcf(struct Qdisc *qd,
unsigned long cl)
{
struct ieee80211_sched_data *q = qdisc_priv(qd);
if (cl)
return NULL;
return &q->filter_list;
}
/* this qdisc is classful (i.e. has classes, some of which may have leaf qdiscs attached)
* - these are the operations on the classes */
static const struct Qdisc_class_ops class_ops =
{
.graft = wme_classop_graft,
.leaf = wme_classop_leaf,
.get = wme_classop_get,
.put = wme_classop_put,
.change = wme_classop_change,
.delete = wme_classop_delete,
.walk = wme_classop_walk,
.tcf_chain = wme_classop_find_tcf,
.bind_tcf = wme_classop_bind,
.unbind_tcf = wme_classop_put,
.dump = wme_classop_dump_class,
};
/* queueing discipline operations */
static struct Qdisc_ops wme_qdisc_ops __read_mostly =
{
.next = NULL,
.cl_ops = &class_ops,
.id = "ieee80211",
.priv_size = sizeof(struct ieee80211_sched_data),
.enqueue = wme_qdiscop_enqueue,
.dequeue = wme_qdiscop_dequeue,
.requeue = wme_qdiscop_requeue,
.drop = NULL, /* drop not needed since we are always the root qdisc */
.init = wme_qdiscop_init,
.reset = wme_qdiscop_reset,
.destroy = wme_qdiscop_destroy,
.change = wme_qdiscop_tune,
.dump = wme_qdiscop_dump,
};
void ieee80211_install_qdisc(struct net_device *dev)
{
struct Qdisc *qdisc;
qdisc = qdisc_create_dflt(dev, &wme_qdisc_ops, TC_H_ROOT);
if (!qdisc) {
printk(KERN_ERR "%s: qdisc installation failed\n", dev->name);
return;
}
/* same handle as would be allocated by qdisc_alloc_handle() */
qdisc->handle = 0x80010000;
qdisc_lock_tree(dev);
list_add_tail(&qdisc->list, &dev->qdisc_list);
dev->qdisc_sleeping = qdisc;
qdisc_unlock_tree(dev);
}
int ieee80211_qdisc_installed(struct net_device *dev)
{
return dev->qdisc_sleeping->ops == &wme_qdisc_ops;
}
int ieee80211_wme_register(void)
{
return register_qdisc(&wme_qdisc_ops);
}
void ieee80211_wme_unregister(void)
{
unregister_qdisc(&wme_qdisc_ops);
}
int ieee80211_ht_agg_queue_add(struct ieee80211_local *local,
struct sta_info *sta, u16 tid)
{
int i;
struct ieee80211_sched_data *q =
qdisc_priv(local->mdev->qdisc_sleeping);
DECLARE_MAC_BUF(mac);
/* prepare the filter and save it for the SW queue
* matching the recieved HW queue */
/* try to get a Qdisc from the pool */
for (i = IEEE80211_TX_QUEUE_BEACON; i < local->hw.queues; i++)
if (!test_and_set_bit(i, q->qdisc_pool)) {
ieee80211_stop_queue(local_to_hw(local), i);
sta->tid_to_tx_q[tid] = i;
/* IF there are already pending packets
* on this tid first we need to drain them
* on the previous queue
* since HT is strict in order */
#ifdef CONFIG_MAC80211_HT_DEBUG
if (net_ratelimit())
printk(KERN_DEBUG "allocated aggregation queue"
" %d tid %d addr %s pool=0x%lX",
i, tid, print_mac(mac, sta->addr),
q->qdisc_pool[0]);
#endif /* CONFIG_MAC80211_HT_DEBUG */
return 0;
}
return -EAGAIN;
}
/**
* the caller needs to hold local->mdev->queue_lock
*/
void ieee80211_ht_agg_queue_remove(struct ieee80211_local *local,
struct sta_info *sta, u16 tid,
u8 requeue)
{
struct ieee80211_sched_data *q =
qdisc_priv(local->mdev->qdisc_sleeping);
int agg_queue = sta->tid_to_tx_q[tid];
/* return the qdisc to the pool */
clear_bit(agg_queue, q->qdisc_pool);
sta->tid_to_tx_q[tid] = local->hw.queues;
if (requeue)
ieee80211_requeue(local, agg_queue);
else
q->queues[agg_queue]->ops->reset(q->queues[agg_queue]);
}
void ieee80211_requeue(struct ieee80211_local *local, int queue)
{
struct Qdisc *root_qd = local->mdev->qdisc_sleeping;
struct ieee80211_sched_data *q = qdisc_priv(root_qd);
struct Qdisc *qdisc = q->queues[queue];
struct sk_buff *skb = NULL;
u32 len = qdisc->q.qlen;
if (!qdisc || !qdisc->dequeue)
return;
printk(KERN_DEBUG "requeue: qlen = %d\n", qdisc->q.qlen);
for (len = qdisc->q.qlen; len > 0; len--) {
skb = qdisc->dequeue(qdisc);
root_qd->q.qlen--;
/* packet will be classified again and */
/* skb->packet_data->queue will be overridden if needed */
if (skb)
wme_qdiscop_enqueue(skb, root_qd);
}
}