[3.11.y.z extended stable] Patch "ipv4: fix tunneled VM traffic over hw VXLAN/GRE GSO NIC" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Tue Jan 21 11:02:21 UTC 2014


This is a note to let you know that I have just added a patch titled

    ipv4: fix tunneled VM traffic over hw VXLAN/GRE GSO NIC

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 4733d6393c2f14ff6e01cb6274dab41e7f578a19 Mon Sep 17 00:00:00 2001
From: Wei-Chun Chao <weichunc at plumgrid.com>
Date: Thu, 26 Dec 2013 13:10:22 -0800
Subject: ipv4: fix tunneled VM traffic over hw VXLAN/GRE GSO NIC

commit 7a7ffbabf99445704be01bff5d7e360da908cf8e upstream.

VM to VM GSO traffic is broken if it goes through VXLAN or GRE
tunnel and the physical NIC on the host supports hardware VXLAN/GRE
GSO offload (e.g. bnx2x and next-gen mlx4).

Two issues -
(VXLAN) VM traffic has SKB_GSO_DODGY and SKB_GSO_UDP_TUNNEL with
SKB_GSO_TCP/UDP set depending on the inner protocol. GSO header
integrity check fails in udp4_ufo_fragment if inner protocol is
TCP. Also gso_segs is calculated incorrectly using skb->len that
includes tunnel header. Fix: robust check should only be applied
to the inner packet.

(VXLAN & GRE) Once GSO header integrity check passes, NULL segs
is returned and the original skb is sent to hardware. However the
tunnel header is already pulled. Fix: tunnel header needs to be
restored so that hardware can perform GSO properly on the original
packet.

Signed-off-by: Wei-Chun Chao <weichunc at plumgrid.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: backported to 3.11: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 include/linux/netdevice.h | 13 +++++++++++++
 net/ipv4/gre_offload.c    | 11 +++++++----
 net/ipv4/udp.c            |  6 +++++-
 net/ipv4/udp_offload.c    | 37 +++++++++++++++++++------------------
 4 files changed, 44 insertions(+), 23 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1ffe7d7..324521b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2879,6 +2879,19 @@ static inline void netif_set_gso_max_size(struct net_device *dev,
 	dev->gso_max_size = size;
 }

+static inline void skb_gso_error_unwind(struct sk_buff *skb, __be16 protocol,
+					int pulled_hlen, u16 mac_offset,
+					int mac_len)
+{
+	skb->protocol = protocol;
+	skb->encapsulation = 1;
+	skb_push(skb, pulled_hlen);
+	skb_reset_transport_header(skb);
+	skb->mac_header = mac_offset;
+	skb->network_header = skb->mac_header + mac_len;
+	skb->mac_len = mac_len;
+}
+
 static inline bool netif_is_bond_master(struct net_device *dev)
 {
 	return dev->flags & IFF_MASTER && dev->priv_flags & IFF_BONDING;
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 55e6bfb..db98705 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -28,6 +28,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 	netdev_features_t enc_features;
 	int ghl = GRE_HEADER_SECTION;
 	struct gre_base_hdr *greh;
+	u16 mac_offset = skb->mac_header;
 	int mac_len = skb->mac_len;
 	__be16 protocol = skb->protocol;
 	int tnl_hlen;
@@ -57,13 +58,13 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 	} else
 		csum = false;

+	if (unlikely(!pskb_may_pull(skb, ghl)))
+		goto out;
+
 	/* setup inner skb. */
 	skb->protocol = greh->protocol;
 	skb->encapsulation = 0;

-	if (unlikely(!pskb_may_pull(skb, ghl)))
-		goto out;
-
 	__skb_pull(skb, ghl);
 	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, skb_inner_network_offset(skb));
@@ -72,8 +73,10 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 	/* segment inner packet. */
 	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
 	segs = skb_mac_gso_segment(skb, enc_features);
-	if (!segs || IS_ERR(segs))
+	if (!segs || IS_ERR(segs)) {
+		skb_gso_error_unwind(skb, protocol, ghl, mac_offset, mac_len);
 		goto out;
+	}

 	skb = segs;
 	tnl_hlen = skb_tnl_header_len(skb);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index b30deb9..e85a25c 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2293,6 +2293,7 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 				       netdev_features_t features)
 {
 	struct sk_buff *segs = ERR_PTR(-EINVAL);
+	u16 mac_offset = skb->mac_header;
 	int mac_len = skb->mac_len;
 	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
 	__be16 protocol = skb->protocol;
@@ -2312,8 +2313,11 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 	/* segment inner packet. */
 	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
 	segs = skb_mac_gso_segment(skb, enc_features);
-	if (!segs || IS_ERR(segs))
+	if (!segs || IS_ERR(segs)) {
+		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
+				     mac_len);
 		goto out;
+	}

 	outer_hlen = skb_tnl_header_len(skb);
 	skb = segs;
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index f35ecca..6b809e4 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -41,6 +41,14 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 {
 	struct sk_buff *segs = ERR_PTR(-EINVAL);
 	unsigned int mss;
+	int offset;
+	__wsum csum;
+
+	if (skb->encapsulation &&
+	    skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) {
+		segs = skb_udp_tunnel_segment(skb, features);
+		goto out;
+	}

 	mss = skb_shinfo(skb)->gso_size;
 	if (unlikely(skb->len <= mss))
@@ -62,27 +70,20 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 		goto out;
 	}

+	/* Do software UFO. Complete and fill in the UDP checksum as
+	 * HW cannot do checksum of UDP packets sent as multiple
+	 * IP fragments.
+	 */
+	offset = skb_checksum_start_offset(skb);
+	csum = skb_checksum(skb, offset, skb->len - offset, 0);
+	offset += skb->csum_offset;
+	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
+	skb->ip_summed = CHECKSUM_NONE;
+
 	/* Fragment the skb. IP headers of the fragments are updated in
 	 * inet_gso_segment()
 	 */
-	if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
-		segs = skb_udp_tunnel_segment(skb, features);
-	else {
-		int offset;
-		__wsum csum;
-
-		/* Do software UFO. Complete and fill in the UDP checksum as
-		 * HW cannot do checksum of UDP packets sent as multiple
-		 * IP fragments.
-		 */
-		offset = skb_checksum_start_offset(skb);
-		csum = skb_checksum(skb, offset, skb->len - offset, 0);
-		offset += skb->csum_offset;
-		*(__sum16 *)(skb->data + offset) = csum_fold(csum);
-		skb->ip_summed = CHECKSUM_NONE;
-
-		segs = skb_segment(skb, features);
-	}
+	segs = skb_segment(skb, features);
 out:
 	return segs;
 }
--
1.8.3.2





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