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From: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>
Cc: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>,
	netdev@vger.kernel.org,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Jakub Kicinski <jakub.kicinski@netronome.com>,
	John Fastabend <john.fastabend@gmail.com>
Subject: [PATCH v6 bpf-next 3/9] veth: Avoid drops by oversized packets when XDP is enabled
Date: Mon, 30 Jul 2018 19:43:45 +0900	[thread overview]
Message-ID: <1532947431-2737-4-git-send-email-makita.toshiaki@lab.ntt.co.jp> (raw)
In-Reply-To: <1532947431-2737-1-git-send-email-makita.toshiaki@lab.ntt.co.jp>

Oversized packets including GSO packets can be dropped if XDP is
enabled on receiver side, so don't send such packets from peer.

Drop TSO and SCTP fragmentation features so that veth devices themselves
segment packets with XDP enabled. Also cap MTU accordingly.

v4:
- Don't auto-adjust MTU but cap max MTU.

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
---
 drivers/net/veth.c | 47 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index d3b9f10..9edf104 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -543,6 +543,23 @@ static int veth_get_iflink(const struct net_device *dev)
 	return iflink;
 }
 
+static netdev_features_t veth_fix_features(struct net_device *dev,
+					   netdev_features_t features)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer;
+
+	peer = rtnl_dereference(priv->peer);
+	if (peer) {
+		struct veth_priv *peer_priv = netdev_priv(peer);
+
+		if (peer_priv->_xdp_prog)
+			features &= ~NETIF_F_GSO_SOFTWARE;
+	}
+
+	return features;
+}
+
 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
 {
 	struct veth_priv *peer_priv, *priv = netdev_priv(dev);
@@ -572,6 +589,7 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
 	struct veth_priv *priv = netdev_priv(dev);
 	struct bpf_prog *old_prog;
 	struct net_device *peer;
+	unsigned int max_mtu;
 	int err;
 
 	old_prog = priv->_xdp_prog;
@@ -585,6 +603,15 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
 			goto err;
 		}
 
+		max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
+			  peer->hard_header_len -
+			  SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+		if (peer->mtu > max_mtu) {
+			NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
+			err = -ERANGE;
+			goto err;
+		}
+
 		if (dev->flags & IFF_UP) {
 			err = veth_enable_xdp(dev);
 			if (err) {
@@ -592,14 +619,29 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
 				goto err;
 			}
 		}
+
+		if (!old_prog) {
+			peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
+			peer->max_mtu = max_mtu;
+		}
 	}
 
 	if (old_prog) {
-		if (!prog && dev->flags & IFF_UP)
-			veth_disable_xdp(dev);
+		if (!prog) {
+			if (dev->flags & IFF_UP)
+				veth_disable_xdp(dev);
+
+			if (peer) {
+				peer->hw_features |= NETIF_F_GSO_SOFTWARE;
+				peer->max_mtu = ETH_MAX_MTU;
+			}
+		}
 		bpf_prog_put(old_prog);
 	}
 
+	if ((!!old_prog ^ !!prog) && peer)
+		netdev_update_features(peer);
+
 	return 0;
 err:
 	priv->_xdp_prog = old_prog;
@@ -644,6 +686,7 @@ static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
 	.ndo_poll_controller	= veth_poll_controller,
 #endif
 	.ndo_get_iflink		= veth_get_iflink,
+	.ndo_fix_features	= veth_fix_features,
 	.ndo_features_check	= passthru_features_check,
 	.ndo_set_rx_headroom	= veth_set_rx_headroom,
 	.ndo_bpf		= veth_xdp,
-- 
1.8.3.1

  parent reply	other threads:[~2018-07-30 12:19 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-30 10:43 [PATCH v6 bpf-next 0/9] veth: Driver XDP Toshiaki Makita
2018-07-30 10:43 ` [PATCH v6 bpf-next 1/9] net: Export skb_headers_offset_update Toshiaki Makita
2018-07-30 10:43 ` [PATCH v6 bpf-next 2/9] veth: Add driver XDP Toshiaki Makita
2018-07-30 10:43 ` Toshiaki Makita [this message]
2018-07-30 10:43 ` [PATCH v6 bpf-next 4/9] veth: Handle xdp_frames in xdp napi ring Toshiaki Makita
2018-07-31 10:26   ` Jesper Dangaard Brouer
2018-07-31 10:40     ` Toshiaki Makita
2018-07-31 12:46       ` Jesper Dangaard Brouer
2018-08-01  5:41         ` Toshiaki Makita
2018-08-01 15:09           ` Jesper Dangaard Brouer
2018-07-30 10:43 ` [PATCH v6 bpf-next 5/9] veth: Add ndo_xdp_xmit Toshiaki Makita
2018-07-30 10:43 ` [PATCH v6 bpf-next 6/9] bpf: Make redirect_info accessible from modules Toshiaki Makita
2018-07-30 10:43 ` [PATCH v6 bpf-next 7/9] xdp: Helpers for disabling napi_direct of xdp_return_frame Toshiaki Makita
2018-07-30 10:43 ` [PATCH v6 bpf-next 8/9] veth: Add XDP TX and REDIRECT Toshiaki Makita
2018-07-30 10:43 ` [PATCH v6 bpf-next 9/9] veth: Support per queue XDP ring Toshiaki Makita

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