[ovs-dev] [bug 7759 05/11] dpif-linux: Use get_32aligned_u64() in an appropriate place.
Ben Pfaff
blp at nicira.com
Tue Oct 11 19:26:06 UTC 2011
On Tue, Oct 11, 2011 at 11:08:26AM -0700, Jesse Gross wrote:
> On Wed, Oct 5, 2011 at 11:27 AM, Ben Pfaff <blp at nicira.com> wrote:
> > ---
> > ??lib/dpif-linux.c | ?? 10 +++++-----
> > ??1 files changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/lib/dpif-linux.c b/lib/dpif-linux.c
> > index 4ddd464..79e84d6 100644
> > --- a/lib/dpif-linux.c
> > +++ b/lib/dpif-linux.c
> > @@ -102,9 +102,9 @@ struct dpif_linux_flow {
> >
> > ?? ?? /* Attributes.
> > ?? ?? ??*
> > - ?? ?? * The 'stats' and 'used' members point to 64-bit data that might only be
> > - ?? ?? * aligned on 32-bit boundaries, so get_unaligned_u64() should be used to
> > - ?? ?? * access their values.
> > + ?? ?? * The 'stats' member points to 64-bit data that might only be aligned on
> > + ?? ?? * 32-bit boundaries, so get_unaligned_u64() should be used to access its
> > + ?? ?? * values.
>
> This looks good. However, when reviewing this I noticed that we seem
> to access vport stats in an unsafe manner since they are also 64-bit
> stats aligned on 32-bit boundaries.
Oops. Here's a fix.
--8<--------------------------cut here-------------------------->8--
From: Ben Pfaff <blp at nicira.com>
Date: Tue, 11 Oct 2011 12:24:41 -0700
Subject: [PATCH] dpif-linux: Avoid unaligned accesses to vport stats sent by
the datapath.
Reported-by: Jesse Gross <jesse at nicira.com>
---
lib/dpif-linux.h | 6 +++++-
lib/netdev-vport.c | 33 ++++++++++++++++++++-------------
2 files changed, 25 insertions(+), 14 deletions(-)
diff --git a/lib/dpif-linux.h b/lib/dpif-linux.h
index c72ea88..a9f8bfe 100644
--- a/lib/dpif-linux.h
+++ b/lib/dpif-linux.h
@@ -32,7 +32,11 @@ struct dpif_linux_vport {
uint32_t port_no; /* UINT32_MAX if unknown. */
enum ovs_vport_type type;
- /* Attributes. */
+ /* Attributes.
+ *
+ * The 'stats' member points to 64-bit data that might only be aligned on
+ * 32-bit boundaries, so use get_unaligned_u64() to access its values.
+ */
const char *name; /* OVS_VPORT_ATTR_NAME. */
const uint32_t *upcall_pid; /* OVS_VPORT_ATTR_UPCALL_PID. */
const struct ovs_vport_stats *stats; /* OVS_VPORT_ATTR_STATS. */
diff --git a/lib/netdev-vport.c b/lib/netdev-vport.c
index 06ec8fb..70cdf29 100644
--- a/lib/netdev-vport.c
+++ b/lib/netdev-vport.c
@@ -44,6 +44,7 @@
#include "route-table.h"
#include "shash.h"
#include "socket-util.h"
+#include "unaligned.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(netdev_vport);
@@ -361,22 +362,21 @@ netdev_vport_get_etheraddr(const struct netdev *netdev,
return error;
}
-#define COPY_OVS_STATS \
- dst->rx_packets = src->rx_packets; \
- dst->tx_packets = src->tx_packets; \
- dst->rx_bytes = src->rx_bytes; \
- dst->tx_bytes = src->tx_bytes; \
- dst->rx_errors = src->rx_errors; \
- dst->tx_errors = src->tx_errors; \
- dst->rx_dropped = src->rx_dropped; \
- dst->tx_dropped = src->tx_dropped;
-
-/* Copies 'src' into 'dst', performing format conversion in the process. */
+/* Copies 'src' into 'dst', performing format conversion in the process.
+ *
+ * 'src' is allowed to be misaligned. */
static void
netdev_stats_from_ovs_vport_stats(struct netdev_stats *dst,
const struct ovs_vport_stats *src)
{
- COPY_OVS_STATS
+ dst->rx_packets = get_unaligned_u64(&src->rx_packets);
+ dst->tx_packets = get_unaligned_u64(&src->tx_packets);
+ dst->rx_bytes = get_unaligned_u64(&src->rx_bytes);
+ dst->tx_bytes = get_unaligned_u64(&src->tx_bytes);
+ dst->rx_errors = get_unaligned_u64(&src->rx_errors);
+ dst->tx_errors = get_unaligned_u64(&src->tx_errors);
+ dst->rx_dropped = get_unaligned_u64(&src->rx_dropped);
+ dst->tx_dropped = get_unaligned_u64(&src->tx_dropped);
dst->multicast = 0;
dst->collisions = 0;
dst->rx_length_errors = 0;
@@ -397,7 +397,14 @@ static void
netdev_stats_to_ovs_vport_stats(struct ovs_vport_stats *dst,
const struct netdev_stats *src)
{
- COPY_OVS_STATS
+ dst->rx_packets = src->rx_packets;
+ dst->tx_packets = src->tx_packets;
+ dst->rx_bytes = src->rx_bytes;
+ dst->tx_bytes = src->tx_bytes;
+ dst->rx_errors = src->rx_errors;
+ dst->tx_errors = src->tx_errors;
+ dst->rx_dropped = src->rx_dropped;
+ dst->tx_dropped = src->tx_dropped;
}
int
--
1.7.4.4
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