netdev - [PATCH net-next] gro: introduce gro_mac_header

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 06 Feb 2012 17:27:07 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Or Gerlitz <ogerlitz@...lanox.com>
Cc:	"Hefty, Sean" <sean.hefty@...el.com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	linux-rdma <linux-rdma@...r.kernel.org>,
	Shlomo Pongratz <shlomop@...lanox.com>,
	Roland Dreier <roland@...nel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net-next] gro: introduce gro_mac_header_len

Shlomo Pongratz reported GRO L2 header check was suited for Ethernet
only, and failed on IB/ipoib traffic.

He provided a patch faking a zeroed header to let GRO aggregates frames.

Roland Dreier, Herbert Xu, and others suggested we change GRO L2 header
check to be more generic.

This patch introduces a new netdevice field, gro_mac_header_len, giving
L2 header length, default to ETH_HLEN (14 bytes)

A device setup function can override this default value.

__napi_gro_receive() has special handling for the common case (Ethernet)
to avoid a memcmp() call and use an inline optimized function instead.

Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
Reported-by: Shlomo Pongratz <shlomop@...lanox.com>
Cc: Roland Dreier <roland@...nel.org>
Cc: Or Gerlitz <ogerlitz@...lanox.com>
Cc: Herbert Xu <herbert@...dor.apana.org.au>
---
 include/linux/netdevice.h |    1 +
 net/core/dev.c            |   11 +++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0eac07c..d17192b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1095,6 +1095,7 @@ struct net_device {
 	unsigned int		mtu;	/* interface MTU value		*/
 	unsigned short		type;	/* interface hardware type	*/
 	unsigned short		hard_header_len;	/* hardware hdr length	*/
+	unsigned int		gro_mac_header_len;
 
 	/* extra head- and tailroom the hardware may need, but not in all cases
 	 * can this be guaranteed, especially tailroom. Some cases also use
diff --git a/net/core/dev.c b/net/core/dev.c
index f124947..0b43939 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3491,14 +3491,20 @@ static inline gro_result_t
 __napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
 {
 	struct sk_buff *p;
+	unsigned int maclen = skb->dev->gro_mac_header_len;
 
 	for (p = napi->gro_list; p; p = p->next) {
 		unsigned long diffs;
 
 		diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
 		diffs |= p->vlan_tci ^ skb->vlan_tci;
-		diffs |= compare_ether_header(skb_mac_header(p),
-					      skb_gro_mac_header(skb));
+		if (maclen == ETH_HLEN)
+			diffs |= compare_ether_header(skb_mac_header(p),
+						      skb_gro_mac_header(skb));
+		else if (!diffs)
+			diffs = memcmp(skb_mac_header(p),
+				       skb_gro_mac_header(skb),
+				       maclen);
 		NAPI_GRO_CB(p)->same_flow = !diffs;
 		NAPI_GRO_CB(p)->flush = 0;
 	}
@@ -5962,6 +5968,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	INIT_LIST_HEAD(&dev->unreg_list);
 	INIT_LIST_HEAD(&dev->link_watch_list);
 	dev->priv_flags = IFF_XMIT_DST_RELEASE;
+	dev->gro_mac_header_len = ETH_HLEN;
 	setup(dev);
 
 	dev->num_tx_queues = txqs;


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html