On Wed, Feb 01, 2017 at 07:10:05PM +0200, Leon Romanovsky wrote:
> From: Erez Shitrit <erezsh@xxxxxxxxxxxx>
>
> When sending packet to destination that was not resolved yet
> via path query, the driver keeps the skb and tries to re-send it
> again when the path is resolved.
>
> But when re-sending via dev_queue_xmit the kernel doesn't call
> to dev_hard_header, so IPoIB needs to keep 20 bytes in the skb
> and to put the destination address inside them.
>
> In that way the dev_start_xmit will have the correct destination,
> and the driver won't take the destination from the skb->data, while
> nothing exists there, which causes to packet be be dropped.
>
> The test flow is:
> 1. Run the SM on remote node,
> 2. Restart the driver.
> 4. Ping some destination,
> 3. Observe that first ICMP request will be dropped.
>
> Fixes: fc791b633515 ("IB/ipoib: move back IB LL address into the hard header")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.8+
> Signed-off-by: Erez Shitrit <erezsh@xxxxxxxxxxxx>
> Signed-off-by: Noa Osherovich <noaos@xxxxxxxxxxxx>
> Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
> ---
> drivers/infiniband/ulp/ipoib/ipoib_main.c | 30 +++++++++++++++++-------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
> index 3ce0765a05ab..205fa1c7ec4d 100644
> --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
> +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
> @@ -716,6 +716,14 @@ int ipoib_check_sm_sendonly_fullmember_support(struct ipoib_dev_priv *priv)
> return ret;
> }
>
> +static void push_pseudo_header(struct sk_buff *skb, const char *daddr)
> +{
> + struct ipoib_pseudo_header *phdr;
> +
> + phdr = (struct ipoib_pseudo_header *)skb_push(skb, sizeof(*phdr));
> + memcpy(phdr->hwaddr, daddr, INFINIBAND_ALEN);
> +}
> +
> void ipoib_flush_paths(struct net_device *dev)
> {
> struct ipoib_dev_priv *priv = netdev_priv(dev);
> @@ -940,8 +948,7 @@ static void neigh_add_path(struct sk_buff *skb, u8 *daddr,
> }
> if (skb_queue_len(&neigh->queue) <
> IPOIB_MAX_PATH_REC_QUEUE) {
> - /* put pseudoheader back on for next time */
> - skb_push(skb, IPOIB_PSEUDO_LEN);
> + push_pseudo_header(skb, neigh->daddr);
> __skb_queue_tail(&neigh->queue, skb);
> } else {
> ipoib_warn(priv, "queue length limit %d. Packet drop.\n",
> @@ -959,10 +966,12 @@ static void neigh_add_path(struct sk_buff *skb, u8 *daddr,
>
> if (!path->query && path_rec_start(dev, path))
> goto err_path;
> - if (skb_queue_len(&neigh->queue) < IPOIB_MAX_PATH_REC_QUEUE)
> + if (skb_queue_len(&neigh->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
> + push_pseudo_header(skb, neigh->daddr);
> __skb_queue_tail(&neigh->queue, skb);
> - else
> + } else {
> goto err_drop;
> + }
> }
>
> spin_unlock_irqrestore(&priv->lock, flags);
> @@ -998,8 +1007,7 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
> }
> if (path) {
> if (skb_queue_len(&path->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
> - /* put pseudoheader back on for next time */
> - skb_push(skb, IPOIB_PSEUDO_LEN);
> + push_pseudo_header(skb, phdr->hwaddr);
> __skb_queue_tail(&path->queue, skb);
> } else {
> ++dev->stats.tx_dropped;
> @@ -1031,8 +1039,7 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
> return;
> } else if ((path->query || !path_rec_start(dev, path)) &&
> skb_queue_len(&path->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
> - /* put pseudoheader back on for next time */
> - skb_push(skb, IPOIB_PSEUDO_LEN);
> + push_pseudo_header(skb, phdr->hwaddr);
> __skb_queue_tail(&path->queue, skb);
> } else {
> ++dev->stats.tx_dropped;
> @@ -1113,8 +1120,7 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
> }
>
> if (skb_queue_len(&neigh->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
> - /* put pseudoheader back on for next time */
> - skb_push(skb, sizeof(*phdr));
> + push_pseudo_header(skb, phdr->hwaddr);
> spin_lock_irqsave(&priv->lock, flags);
> __skb_queue_tail(&neigh->queue, skb);
> spin_unlock_irqrestore(&priv->lock, flags);
> @@ -1146,7 +1152,6 @@ static int ipoib_hard_header(struct sk_buff *skb,
> unsigned short type,
> const void *daddr, const void *saddr, unsigned len)
> {
> - struct ipoib_pseudo_header *phdr;
> struct ipoib_header *header;
>
> header = (struct ipoib_header *) skb_push(skb, sizeof *header);
> @@ -1159,8 +1164,7 @@ static int ipoib_hard_header(struct sk_buff *skb,
> * destination address into skb hard header so we can figure out where
> * to send the packet later.
> */
> - phdr = (struct ipoib_pseudo_header *) skb_push(skb, sizeof(*phdr));
> - memcpy(phdr->hwaddr, daddr, INFINIBAND_ALEN);
> + push_pseudo_header(skb, daddr);
>
> return IPOIB_HARD_LEN;
> }
Tested-by: Yuval Shaia <yuval.shaia@xxxxxxxxxx>
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