From: Atzm Watanabe <atzm@stratosphere•co.jp>
To: netdev@vger•kernel.org
Cc: "Stephen Hemminger" <stephen@networkplumber•org>,
"Ben Hutchings" <bhutchings@solarflare•com>,
"David Miller" <davem@davemloft•net>,
"Daniel Borkmann" <dborkman@redhat•com>,
"David Laight" <David.Laight@ACULAB•COM>
Subject: [PATCH v4 1/3] packet: make aligned size of struct tpacket{2,3}_hdr clear
Date: Tue, 17 Dec 2013 22:53:32 +0900 [thread overview]
Message-ID: <87fvpr7fdv.wl%atzm@stratosphere.co.jp> (raw)
struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT.
We may add members to them until current aligned size without forcing
userspace to call getsockopt(..., PACKET_HDRLEN, ...).
Signed-off-by: Atzm Watanabe <atzm@stratosphere•co.jp>
---
net/packet/af_packet.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index cc803c6..c6baa59 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1812,6 +1812,13 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
struct timespec ts;
__u32 ts_status;
+ /* struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT.
+ * We may add members to them until current aligned size without forcing
+ * userspace to call getsockopt(..., PACKET_HDRLEN, ...).
+ */
+ BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h2)) != 32);
+ BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h3)) != 48);
+
if (skb->pkt_type == PACKET_LOOPBACK)
goto drop;
--
1.8.1.5
next reply other threads:[~2013-12-17 13:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-17 13:53 Atzm Watanabe [this message]
2013-12-17 14:02 ` [PATCH v4 1/3] packet: make aligned size of struct tpacket{2,3}_hdr clear Daniel Borkmann
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