* [PATCH v4 1/3] packet: make aligned size of struct tpacket{2,3}_hdr clear
@ 2013-12-17 13:53 Atzm Watanabe
2013-12-17 14:02 ` Daniel Borkmann
0 siblings, 1 reply; 2+ messages in thread
From: Atzm Watanabe @ 2013-12-17 13:53 UTC (permalink / raw)
To: netdev
Cc: Stephen Hemminger, Ben Hutchings, David Miller, Daniel Borkmann,
David Laight
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
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH v4 1/3] packet: make aligned size of struct tpacket{2,3}_hdr clear
2013-12-17 13:53 [PATCH v4 1/3] packet: make aligned size of struct tpacket{2,3}_hdr clear Atzm Watanabe
@ 2013-12-17 14:02 ` Daniel Borkmann
0 siblings, 0 replies; 2+ messages in thread
From: Daniel Borkmann @ 2013-12-17 14:02 UTC (permalink / raw)
To: Atzm Watanabe
Cc: netdev, Stephen Hemminger, Ben Hutchings, David Miller,
David Laight
On 12/17/2013 02:53 PM, Atzm Watanabe wrote:
> 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>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2013-12-17 13:53 [PATCH v4 1/3] packet: make aligned size of struct tpacket{2,3}_hdr clear Atzm Watanabe
2013-12-17 14:02 ` Daniel Borkmann
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