[PATCH net-next v2] bareudp: Reverted support to enable & disable rx metadata collection

[PATCH net-next v2] bareudp: Reverted support to enable & disable rx metadata collection

[Martin Varghese]

From: Martin Varghese <martin.varghese@nokia.com>

The commit fe80536acf83 ("bareudp: Added attribute to enable & disable
rx metadata collection") breaks the the original(5.7) default behavior of
bareudp module to collect RX metadadata at the receive. It was added to
avoid the crash at the kernel neighbour subsytem when packet with metadata
from bareudp is processed. But it is no more needed as the
commit 394de110a733 ("net: Added pointer check for
dst->ops->neigh_lookup in dst_neigh_lookup_skb") solves this crash.

Fixes: fe80536acf83 ("bareudp: Added attribute to enable & disable rx metadata collection")
Signed-off-by: Martin Varghese <martin.varghese@nokia.com>
---
Changes in v2
    - Fixed Documentation.

 Documentation/networking/bareudp.rst |  5 ++---
 drivers/net/bareudp.c                | 21 +++++----------------
 include/uapi/linux/if_link.h         |  1 -
 3 files changed, 7 insertions(+), 20 deletions(-)

diff --git a/Documentation/networking/bareudp.rst b/Documentation/networking/bareudp.rst
index 0e00636d8d74..f2cab0ba116b 100644
--- a/Documentation/networking/bareudp.rst
+++ b/Documentation/networking/bareudp.rst
@@ -49,6 +49,5 @@ The bareudp device could be used along with OVS or flower filter in TC.
 The OVS or TC flower layer must set the tunnel information in SKB dst field before
 sending packet buffer to the bareudp device for transmission. On reception the
 bareudp device decapsulates the udp header and passes the inner packet to the
-network stack. If RX_COLLECT_METADATA flag is enabled in the device the tunnel
-information will be stored in the SKB dst field before the packet buffer is
-passed to the network stack.
+network stack. The tunnel information will be stored in the SKB dst field before
+the packet buffer is passed to the network stack.
diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
index 108a8cafc4f8..44eb2b1d0416 100644
--- a/drivers/net/bareudp.c
+++ b/drivers/net/bareudp.c
@@ -46,7 +46,6 @@ struct bareudp_dev {
 	__be16             port;
 	u16	           sport_min;
 	bool               multi_proto_mode;
-	bool               rx_collect_metadata;
 	struct socket      __rcu *sock;
 	struct list_head   next;        /* bareudp node  on namespace list */
 	struct gro_cells   gro_cells;
@@ -126,14 +125,12 @@ static int bareudp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 		bareudp->dev->stats.rx_dropped++;
 		goto drop;
 	}
-	if (bareudp->rx_collect_metadata) {
-		tun_dst = udp_tun_rx_dst(skb, family, TUNNEL_KEY, 0, 0);
-		if (!tun_dst) {
-			bareudp->dev->stats.rx_dropped++;
-			goto drop;
-		}
-		skb_dst_set(skb, &tun_dst->dst);
+	tun_dst = udp_tun_rx_dst(skb, family, TUNNEL_KEY, 0, 0);
+	if (!tun_dst) {
+		bareudp->dev->stats.rx_dropped++;
+		goto drop;
 	}
+	skb_dst_set(skb, &tun_dst->dst);
 	skb->dev = bareudp->dev;
 	oiph = skb_network_header(skb);
 	skb_reset_network_header(skb);
@@ -577,9 +574,6 @@ static int bareudp2info(struct nlattr *data[], struct bareudp_conf *conf,
 	if (data[IFLA_BAREUDP_MULTIPROTO_MODE])
 		conf->multi_proto_mode = true;
 
-	if (data[IFLA_BAREUDP_RX_COLLECT_METADATA])
-		conf->rx_collect_metadata = true;
-
 	return 0;
 }
 
@@ -617,7 +611,6 @@ static int bareudp_configure(struct net *net, struct net_device *dev,
 	bareudp->ethertype = conf->ethertype;
 	bareudp->sport_min = conf->sport_min;
 	bareudp->multi_proto_mode = conf->multi_proto_mode;
-	bareudp->rx_collect_metadata = conf->rx_collect_metadata;
 
 	err = register_netdevice(dev);
 	if (err)
@@ -676,7 +669,6 @@ static size_t bareudp_get_size(const struct net_device *dev)
 		nla_total_size(sizeof(__be16)) +  /* IFLA_BAREUDP_ETHERTYPE */
 		nla_total_size(sizeof(__u16))  +  /* IFLA_BAREUDP_SRCPORT_MIN */
 		nla_total_size(0)              +  /* IFLA_BAREUDP_MULTIPROTO_MODE */
-		nla_total_size(0)              +  /* IFLA_BAREUDP_RX_COLLECT_METADATA */
 		0;
 }
 
@@ -693,9 +685,6 @@ static int bareudp_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	if (bareudp->multi_proto_mode &&
 	    nla_put_flag(skb, IFLA_BAREUDP_MULTIPROTO_MODE))
 		goto nla_put_failure;
-	if (bareudp->rx_collect_metadata &&
-	    nla_put_flag(skb, IFLA_BAREUDP_RX_COLLECT_METADATA))
-		goto nla_put_failure;
 
 	return 0;
 
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index cc185a007ade..a009365ad67b 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -600,7 +600,6 @@ enum {
 	IFLA_BAREUDP_ETHERTYPE,
 	IFLA_BAREUDP_SRCPORT_MIN,
 	IFLA_BAREUDP_MULTIPROTO_MODE,
-	IFLA_BAREUDP_RX_COLLECT_METADATA,
 	__IFLA_BAREUDP_MAX
 };
 
-- 
2.18.4

Re: [PATCH net-next v2] bareudp: Reverted support to enable & disable rx metadata collection

[Guillaume Nault]

On Thu, Jul 16, 2020 at 09:28:54PM +0530, Martin Varghese wrote:
> From: Martin Varghese <martin.varghese@nokia.com>
> 
> The commit fe80536acf83 ("bareudp: Added attribute to enable & disable
> rx metadata collection") breaks the the original(5.7) default behavior of
> bareudp module to collect RX metadadata at the receive. It was added to
> avoid the crash at the kernel neighbour subsytem when packet with metadata
> from bareudp is processed. But it is no more needed as the
> commit 394de110a733 ("net: Added pointer check for
> dst->ops->neigh_lookup in dst_neigh_lookup_skb") solves this crash.

This patch looks like a complete revert of fe80536acf83, but with a
missing chunk (the rx_collect_metadata field in include/net/bareudp.h).

Why not generating this patch with "git revert fe80536acf83", instead
of doing it manually?. That'd make sure that no chunk is forgotten.

> Fixes: fe80536acf83 ("bareudp: Added attribute to enable & disable rx metadata collection")
> Signed-off-by: Martin Varghese <martin.varghese@nokia.com>