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Commit 63502b8d authored by Stefan Sørensen's avatar Stefan Sørensen Committed by David S. Miller
Browse files

dp83640: Fix receive timestamp race condition 



When timestamping received packets, rx_timestamp_work may be scheduled
before the timestamps is received from the hardware resulting in the
packet beeing delivered without the timestamp.

This is fixed by changing the receive timestamp path:

On receiving a packet that need timestamping, the rxts list is
traversed.  If a match is found, packet+timestamp are delivered,
otherwise the packet is added to a rx_queue.

When a timestamp arrives rx_queue is traversed and if a matching
packet is found, it is delivered with the timestamp. Otherwise the
timestamp is added to the rxts list for matching with packets arriving
later.

In case the hardware drops a timestamp, a workqueue regularly checks
the queue for old packets and delivers them without a timestamp.

Signed-off-by: default avatarStefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 36763266

drivers/net/phy/dp83640.c

+102 −71
Original line number Diff line number Diff line
@@ -74,7 +74,10 @@ 
#define ENDIAN_FLAG	PSF_ENDIAN

#endif



#define SKB_PTP_TYPE(__skb) (*(unsigned int *)((__skb)->cb))

struct dp83640_skb_info {

	int ptp_type;

	unsigned long tmo;

};



struct phy_rxts {

	u16 ns_lo;   /* ns[15:0] */
@@ -768,10 +771,51 @@ static int decode_evnt(struct dp83640_private *dp83640, 
	return parsed * sizeof(u16);

}



static int match(struct sk_buff *skb, unsigned int type, struct rxts *rxts)

{

	u16 *seqid;

	unsigned int offset = 0;

	u8 *msgtype, *data = skb_mac_header(skb);



	/* check sequenceID, messageType, 12 bit hash of offset 20-29 */



	if (type & PTP_CLASS_VLAN)

		offset += VLAN_HLEN;



	switch (type & PTP_CLASS_PMASK) {

	case PTP_CLASS_IPV4:

		offset += ETH_HLEN + IPV4_HLEN(data) + UDP_HLEN;

		break;

	case PTP_CLASS_IPV6:

		offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;

		break;

	case PTP_CLASS_L2:

		offset += ETH_HLEN;

		break;

	default:

		return 0;

	}



	if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))

		return 0;



	if (unlikely(type & PTP_CLASS_V1))

		msgtype = data + offset + OFF_PTP_CONTROL;

	else

		msgtype = data + offset;



	seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);



	return rxts->msgtype == (*msgtype & 0xf) &&

		rxts->seqid   == ntohs(*seqid);

}



static void decode_rxts(struct dp83640_private *dp83640,

			struct phy_rxts *phy_rxts)

{

	struct rxts *rxts;

	struct skb_shared_hwtstamps *shhwtstamps = NULL;

	struct sk_buff *skb;

	unsigned long flags;



	spin_lock_irqsave(&dp83640->rx_lock, flags);
@@ -785,6 +829,25 @@ static void decode_rxts(struct dp83640_private *dp83640, 
	rxts = list_first_entry(&dp83640->rxpool, struct rxts, list);

	list_del_init(&rxts->list);

	phy2rxts(phy_rxts, rxts);



	spin_lock_irqsave(&dp83640->rx_queue.lock, flags);

	skb_queue_walk(&dp83640->rx_queue, skb) {

		struct dp83640_skb_info *skb_info;



		skb_info = (struct dp83640_skb_info *)skb->cb;

		if (match(skb, skb_info->ptp_type, rxts)) {

			__skb_unlink(skb, &dp83640->rx_queue);

			shhwtstamps = skb_hwtstamps(skb);

			memset(shhwtstamps, 0, sizeof(*shhwtstamps));

			shhwtstamps->hwtstamp = ns_to_ktime(rxts->ns);

			netif_rx_ni(skb);

			list_add(&rxts->list, &dp83640->rxpool);

			break;

		}

	}

	spin_unlock_irqrestore(&dp83640->rx_queue.lock, flags);



	if (!shhwtstamps)

		list_add_tail(&rxts->list, &dp83640->rxts);

out:

	spin_unlock_irqrestore(&dp83640->rx_lock, flags);
@@ -887,45 +950,6 @@ static int is_sync(struct sk_buff *skb, int type) 
	return (*msgtype & 0xf) == 0;

}



static int match(struct sk_buff *skb, unsigned int type, struct rxts *rxts)

{

	u16 *seqid;

	unsigned int offset = 0;

	u8 *msgtype, *data = skb_mac_header(skb);



	/* check sequenceID, messageType, 12 bit hash of offset 20-29 */



	if (type & PTP_CLASS_VLAN)

		offset += VLAN_HLEN;



	switch (type & PTP_CLASS_PMASK) {

	case PTP_CLASS_IPV4:

		offset += ETH_HLEN + IPV4_HLEN(data) + UDP_HLEN;

		break;

	case PTP_CLASS_IPV6:

		offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;

		break;

	case PTP_CLASS_L2:

		offset += ETH_HLEN;

		break;

	default:

		return 0;

	}



	if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))

		return 0;



	if (unlikely(type & PTP_CLASS_V1))

		msgtype = data + offset + OFF_PTP_CONTROL;

	else

		msgtype = data + offset;



	seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);



	return rxts->msgtype == (*msgtype & 0xf) &&

		rxts->seqid   == ntohs(*seqid);

}



static void dp83640_free_clocks(void)

{

	struct dp83640_clock *clock;
@@ -1302,44 +1326,34 @@ static void rx_timestamp_work(struct work_struct *work) 
{

	struct dp83640_private *dp83640 =

		container_of(work, struct dp83640_private, ts_work);

	struct list_head *this, *next;

	struct rxts *rxts;

	struct skb_shared_hwtstamps *shhwtstamps;

	struct sk_buff *skb;

	unsigned int type;

	unsigned long flags;



	/* Deliver each deferred packet, with or without a time stamp. */

	/* Deliver expired packets. */

	while ((skb = skb_dequeue(&dp83640->rx_queue))) {

		struct dp83640_skb_info *skb_info;



	while ((skb = skb_dequeue(&dp83640->rx_queue)) != NULL) {

		type = SKB_PTP_TYPE(skb);

		spin_lock_irqsave(&dp83640->rx_lock, flags);

		list_for_each_safe(this, next, &dp83640->rxts) {

			rxts = list_entry(this, struct rxts, list);

			if (match(skb, type, rxts)) {

				shhwtstamps = skb_hwtstamps(skb);

				memset(shhwtstamps, 0, sizeof(*shhwtstamps));

				shhwtstamps->hwtstamp = ns_to_ktime(rxts->ns);

				list_del_init(&rxts->list);

				list_add(&rxts->list, &dp83640->rxpool);

		skb_info = (struct dp83640_skb_info *)skb->cb;

		if (!time_after(jiffies, skb_info->tmo)) {

			skb_queue_head(&dp83640->rx_queue, skb);

			break;

		}

		}

		spin_unlock_irqrestore(&dp83640->rx_lock, flags);



		netif_rx_ni(skb);

	}



	/* Clear out expired time stamps. */



	spin_lock_irqsave(&dp83640->rx_lock, flags);

	prune_rx_ts(dp83640);

	spin_unlock_irqrestore(&dp83640->rx_lock, flags);

	if (!skb_queue_empty(&dp83640->rx_queue))

		schedule_work(&dp83640->ts_work);

}



static bool dp83640_rxtstamp(struct phy_device *phydev,

			     struct sk_buff *skb, int type)

{

	struct dp83640_private *dp83640 = phydev->priv;

	struct dp83640_skb_info *skb_info = (struct dp83640_skb_info *)skb->cb;

	struct list_head *this, *next;

	struct rxts *rxts;

	struct skb_shared_hwtstamps *shhwtstamps = NULL;

	unsigned long flags;



	if (is_status_frame(skb, type)) {

		decode_status_frame(dp83640, skb);
@@ -1350,9 +1364,27 @@ static bool dp83640_rxtstamp(struct phy_device *phydev, 
	if (!dp83640->hwts_rx_en)

		return false;



	SKB_PTP_TYPE(skb) = type;

	spin_lock_irqsave(&dp83640->rx_lock, flags);

	list_for_each_safe(this, next, &dp83640->rxts) {

		rxts = list_entry(this, struct rxts, list);

		if (match(skb, type, rxts)) {

			shhwtstamps = skb_hwtstamps(skb);

			memset(shhwtstamps, 0, sizeof(*shhwtstamps));

			shhwtstamps->hwtstamp = ns_to_ktime(rxts->ns);

			netif_rx_ni(skb);

			list_del_init(&rxts->list);

			list_add(&rxts->list, &dp83640->rxpool);

			break;

		}

	}

	spin_unlock_irqrestore(&dp83640->rx_lock, flags);



	if (!shhwtstamps) {

		skb_info->ptp_type = type;

		skb_info->tmo = jiffies + 2;

		skb_queue_tail(&dp83640->rx_queue, skb);

		schedule_work(&dp83640->ts_work);

	}



	return true;

}
@@ -1373,7 +1405,6 @@ static void dp83640_txtstamp(struct phy_device *phydev, 
	case HWTSTAMP_TX_ON:

		skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;

		skb_queue_tail(&dp83640->tx_queue, skb);

		schedule_work(&dp83640->ts_work);

		break;



	case HWTSTAMP_TX_OFF: