Re: [ovs-dev] [PATCH net-next v3] net: openvswitch: add hash info to upcall

2019-11-12 Thread Tonghao Zhang 
On Wed, Nov 13, 2019 at 12:54 PM Pravin Shelar  wrote:
>
> On Tue, Nov 12, 2019 at 7:09 AM  wrote:
> >
> > From: Tonghao Zhang 
> >
> > When using the kernel datapath, the upcall don't
> > include skb hash info relatived. That will introduce
> > some problem, because the hash of skb is important
> > in kernel stack. For example, VXLAN module uses
> > it to select UDP src port. The tx queue selection
> > may also use the hash in stack.
> >
> > Hash is computed in different ways. Hash is random
> > for a TCP socket, and hash may be computed in hardware,
> > or software stack. Recalculation hash is not easy.
> >
> > Hash of TCP socket is computed:
> >   tcp_v4_connect
> > -> sk_set_txhash (is random)
> >
> >   __tcp_transmit_skb
> > -> skb_set_hash_from_sk
> >
> > There will be one upcall, without information of skb
> > hash, to ovs-vswitchd, for the first packet of a TCP
> > session. The rest packets will be processed in Open vSwitch
> > modules, hash kept. If this tcp session is forward to
> > VXLAN module, then the UDP src port of first tcp packet
> > is different from rest packets.
> >
> > TCP packets may come from the host or dockers, to Open vSwitch.
> > To fix it, we store the hash info to upcall, and restore hash
> > when packets sent back.
> >
> > +---+  +-+
> > |   Docker/VMs  |  | ovs-vswitchd|
> > ++--+  +-++--+
> >  |   ^|
> >  |   ||
> >  |   |  upcallv restore packet hash 
> > (not recalculate)
> >  | +-++--+
> >  |  tap netdev | |   vxlan module
> >  +---> +-->  Open vSwitch ko +-->
> >or internal type| |
> >+-+
> >
> > Reported-at: 
> > https://mail.openvswitch.org/pipermail/ovs-dev/2019-October/364062.html
> > Signed-off-by: Tonghao Zhang 
> > ---
> > v3:
> > * add enum ovs_pkt_hash_types
> > * avoid duplicate call the skb_get_hash_raw.
> > * explain why we should fix this problem.
> > ---
> >  include/uapi/linux/openvswitch.h |  2 ++
> >  net/openvswitch/datapath.c   | 30 +-
> >  net/openvswitch/datapath.h   | 12 
> >  3 files changed, 43 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/openvswitch.h 
> > b/include/uapi/linux/openvswitch.h
> > index 1887a451c388..e65407c1f366 100644
> > --- a/include/uapi/linux/openvswitch.h
> > +++ b/include/uapi/linux/openvswitch.h
> > @@ -170,6 +170,7 @@ enum ovs_packet_cmd {
> >   * output port is actually a tunnel port. Contains the output tunnel key
> >   * extracted from the packet as nested %OVS_TUNNEL_KEY_ATTR_* attributes.
> >   * @OVS_PACKET_ATTR_MRU: Present for an %OVS_PACKET_CMD_ACTION and
> > + * @OVS_PACKET_ATTR_HASH: Packet hash info (e.g. hash, sw_hash and l4_hash 
> > in skb).
> >   * @OVS_PACKET_ATTR_LEN: Packet size before truncation.
> >   * %OVS_PACKET_ATTR_USERSPACE action specify the Maximum received fragment
> >   * size.
> > @@ -190,6 +191,7 @@ enum ovs_packet_attr {
> > OVS_PACKET_ATTR_PROBE,  /* Packet operation is a feature probe,
> >error logging should be suppressed. 
> > */
> > OVS_PACKET_ATTR_MRU,/* Maximum received IP fragment size. */
> > +   OVS_PACKET_ATTR_HASH,   /* Packet hash. */
> > OVS_PACKET_ATTR_LEN,/* Packet size before truncation. */
> > __OVS_PACKET_ATTR_MAX
> >  };
> I agree with Greg, value of existing enums can not be changed in UAPI.
>
> > diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
> > index 2088619c03f0..b556cf62b77c 100644
> > --- a/net/openvswitch/datapath.c
> > +++ b/net/openvswitch/datapath.c
> > @@ -350,7 +350,8 @@ static size_t upcall_msg_size(const struct 
> > dp_upcall_info *upcall_info,
> > size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
> > + nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */
> > + nla_total_size(ovs_key_attr_size()) /* 
> > OVS_PACKET_ATTR_KEY */
> > -   + nla_total_size(sizeof(unsigned int)); /* 
> > OVS_PACKET_ATTR_LEN */
> > +   + nla_total_size(sizeof(unsigned int)) /* 
> > OVS_PACKET_ATTR_LEN */
> > +   + nla_total_size(sizeof(u64)); /* OVS_PACKET_ATTR_HASH */
> >
> > /* OVS_PACKET_ATTR_USERDATA */
> > if (upcall_info->userdata)
> > @@ -393,6 +394,7 @@ static int queue_userspace_packet(struct datapath *dp, 
> > struct sk_buff *skb,
> > size_t len;
> > unsigned int hlen;
> > int err, dp_ifindex;
> > +   u64 hash;
> >
> > dp_ifindex = get_dpifindex(dp);
> > if (!dp_ifindex)
> > @@ -504,6 +506,23 @@ static int

Re: [ovs-dev] [PATCH net-next v3] net: openvswitch: add hash info to upcall

2019-11-12 Thread Pravin Shelar 
On Tue, Nov 12, 2019 at 7:09 AM  wrote:
>
> From: Tonghao Zhang 
>
> When using the kernel datapath, the upcall don't
> include skb hash info relatived. That will introduce
> some problem, because the hash of skb is important
> in kernel stack. For example, VXLAN module uses
> it to select UDP src port. The tx queue selection
> may also use the hash in stack.
>
> Hash is computed in different ways. Hash is random
> for a TCP socket, and hash may be computed in hardware,
> or software stack. Recalculation hash is not easy.
>
> Hash of TCP socket is computed:
>   tcp_v4_connect
> -> sk_set_txhash (is random)
>
>   __tcp_transmit_skb
> -> skb_set_hash_from_sk
>
> There will be one upcall, without information of skb
> hash, to ovs-vswitchd, for the first packet of a TCP
> session. The rest packets will be processed in Open vSwitch
> modules, hash kept. If this tcp session is forward to
> VXLAN module, then the UDP src port of first tcp packet
> is different from rest packets.
>
> TCP packets may come from the host or dockers, to Open vSwitch.
> To fix it, we store the hash info to upcall, and restore hash
> when packets sent back.
>
> +---+  +-+
> |   Docker/VMs  |  | ovs-vswitchd|
> ++--+  +-++--+
>  |   ^|
>  |   ||
>  |   |  upcallv restore packet hash (not 
> recalculate)
>  | +-++--+
>  |  tap netdev | |   vxlan module
>  +---> +-->  Open vSwitch ko +-->
>or internal type| |
>+-+
>
> Reported-at: 
> https://mail.openvswitch.org/pipermail/ovs-dev/2019-October/364062.html
> Signed-off-by: Tonghao Zhang 
> ---
> v3:
> * add enum ovs_pkt_hash_types
> * avoid duplicate call the skb_get_hash_raw.
> * explain why we should fix this problem.
> ---
>  include/uapi/linux/openvswitch.h |  2 ++
>  net/openvswitch/datapath.c   | 30 +-
>  net/openvswitch/datapath.h   | 12 
>  3 files changed, 43 insertions(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/openvswitch.h 
> b/include/uapi/linux/openvswitch.h
> index 1887a451c388..e65407c1f366 100644
> --- a/include/uapi/linux/openvswitch.h
> +++ b/include/uapi/linux/openvswitch.h
> @@ -170,6 +170,7 @@ enum ovs_packet_cmd {
>   * output port is actually a tunnel port. Contains the output tunnel key
>   * extracted from the packet as nested %OVS_TUNNEL_KEY_ATTR_* attributes.
>   * @OVS_PACKET_ATTR_MRU: Present for an %OVS_PACKET_CMD_ACTION and
> + * @OVS_PACKET_ATTR_HASH: Packet hash info (e.g. hash, sw_hash and l4_hash 
> in skb).
>   * @OVS_PACKET_ATTR_LEN: Packet size before truncation.
>   * %OVS_PACKET_ATTR_USERSPACE action specify the Maximum received fragment
>   * size.
> @@ -190,6 +191,7 @@ enum ovs_packet_attr {
> OVS_PACKET_ATTR_PROBE,  /* Packet operation is a feature probe,
>error logging should be suppressed. */
> OVS_PACKET_ATTR_MRU,/* Maximum received IP fragment size. */
> +   OVS_PACKET_ATTR_HASH,   /* Packet hash. */
> OVS_PACKET_ATTR_LEN,/* Packet size before truncation. */
> __OVS_PACKET_ATTR_MAX
>  };
I agree with Greg, value of existing enums can not be changed in UAPI.

> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
> index 2088619c03f0..b556cf62b77c 100644
> --- a/net/openvswitch/datapath.c
> +++ b/net/openvswitch/datapath.c
> @@ -350,7 +350,8 @@ static size_t upcall_msg_size(const struct dp_upcall_info 
> *upcall_info,
> size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
> + nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */
> + nla_total_size(ovs_key_attr_size()) /* OVS_PACKET_ATTR_KEY 
> */
> -   + nla_total_size(sizeof(unsigned int)); /* 
> OVS_PACKET_ATTR_LEN */
> +   + nla_total_size(sizeof(unsigned int)) /* OVS_PACKET_ATTR_LEN 
> */
> +   + nla_total_size(sizeof(u64)); /* OVS_PACKET_ATTR_HASH */
>
> /* OVS_PACKET_ATTR_USERDATA */
> if (upcall_info->userdata)
> @@ -393,6 +394,7 @@ static int queue_userspace_packet(struct datapath *dp, 
> struct sk_buff *skb,
> size_t len;
> unsigned int hlen;
> int err, dp_ifindex;
> +   u64 hash;
>
> dp_ifindex = get_dpifindex(dp);
> if (!dp_ifindex)
> @@ -504,6 +506,23 @@ static int queue_userspace_packet(struct datapath *dp, 
> struct sk_buff *skb,
> pad_packet(dp, user_skb);
> }
>
> +   hash = skb_get_hash_raw(skb);
> +   if (hash) {
Zero hash is valid hash of skb. due to this check packets with zero
hash would not get same vxlan source

Re: [ovs-dev] [PATCH net-next v3] net: openvswitch: add hash info to upcall

2019-11-12 Thread Tonghao Zhang 
On Wed, Nov 13, 2019 at 2:06 AM Gregory Rose  wrote:
>
>
> On 11/12/2019 7:08 AM, xiangxia.m@gmail.com wrote:
> > From: Tonghao Zhang 
> >
> > When using the kernel datapath, the upcall don't
> > include skb hash info relatived. That will introduce
> > some problem, because the hash of skb is important
> > in kernel stack. For example, VXLAN module uses
> > it to select UDP src port. The tx queue selection
> > may also use the hash in stack.
> >
> > Hash is computed in different ways. Hash is random
> > for a TCP socket, and hash may be computed in hardware,
> > or software stack. Recalculation hash is not easy.
> >
> > Hash of TCP socket is computed:
> >tcp_v4_connect
> >  -> sk_set_txhash (is random)
> >
> >__tcp_transmit_skb
> >  -> skb_set_hash_from_sk
> >
> > There will be one upcall, without information of skb
> > hash, to ovs-vswitchd, for the first packet of a TCP
> > session. The rest packets will be processed in Open vSwitch
> > modules, hash kept. If this tcp session is forward to
> > VXLAN module, then the UDP src port of first tcp packet
> > is different from rest packets.
> >
> > TCP packets may come from the host or dockers, to Open vSwitch.
> > To fix it, we store the hash info to upcall, and restore hash
> > when packets sent back.
> >
> > +---+  +-+
> > |   Docker/VMs  |  | ovs-vswitchd|
> > ++--+  +-++--+
> >   |   ^|
> >   |   ||
> >   |   |  upcallv restore packet hash 
> > (not recalculate)
> >   | +-++--+
> >   |  tap netdev | |   vxlan module
> >   +---> +-->  Open vSwitch ko +-->
> > or internal type| |
> > +-+
> >
> > Reported-at: 
> > https://mail.openvswitch.org/pipermail/ovs-dev/2019-October/364062.html
> > Signed-off-by: Tonghao Zhang 
> > ---
> > v3:
> > * add enum ovs_pkt_hash_types
> > * avoid duplicate call the skb_get_hash_raw.
> > * explain why we should fix this problem.
> > ---
> >   include/uapi/linux/openvswitch.h |  2 ++
> >   net/openvswitch/datapath.c   | 30 +-
> >   net/openvswitch/datapath.h   | 12 
> >   3 files changed, 43 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/openvswitch.h 
> > b/include/uapi/linux/openvswitch.h
> > index 1887a451c388..e65407c1f366 100644
> > --- a/include/uapi/linux/openvswitch.h
> > +++ b/include/uapi/linux/openvswitch.h
> > @@ -170,6 +170,7 @@ enum ovs_packet_cmd {
> >* output port is actually a tunnel port. Contains the output tunnel key
> >* extracted from the packet as nested %OVS_TUNNEL_KEY_ATTR_* attributes.
> >* @OVS_PACKET_ATTR_MRU: Present for an %OVS_PACKET_CMD_ACTION and
> > + * @OVS_PACKET_ATTR_HASH: Packet hash info (e.g. hash, sw_hash and l4_hash 
> > in skb).
> >* @OVS_PACKET_ATTR_LEN: Packet size before truncation.
> >* %OVS_PACKET_ATTR_USERSPACE action specify the Maximum received fragment
> >* size.
> > @@ -190,6 +191,7 @@ enum ovs_packet_attr {
> >   OVS_PACKET_ATTR_PROBE,  /* Packet operation is a feature probe,
> >  error logging should be suppressed. */
> >   OVS_PACKET_ATTR_MRU,/* Maximum received IP fragment size. */
> > + OVS_PACKET_ATTR_HASH,   /* Packet hash. */
> >   OVS_PACKET_ATTR_LEN,/* Packet size before truncation. */
> >   __OVS_PACKET_ATTR_MAX
> >   };
>
> Why do you add the new enum before the last entry OVS_PACKET_ATTR_LEN
> instead of
> just adding it to the end of the list?
Should be at end of the list, but I run the "make check" without patch
for ovs-vswitchd,
There is not error. There is not a OVS_PACKET_ATTR_LEN test case ?
I will change the order of enum in next version, thanks.
> Just curious.
>
> - Greg
>
> > diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
> > index 2088619c03f0..b556cf62b77c 100644
> > --- a/net/openvswitch/datapath.c
> > +++ b/net/openvswitch/datapath.c
> > @@ -350,7 +350,8 @@ static size_t upcall_msg_size(const struct 
> > dp_upcall_info *upcall_info,
> >   size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
> >   + nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */
> >   + nla_total_size(ovs_key_attr_size()) /* OVS_PACKET_ATTR_KEY 
> > */
> > - + nla_total_size(sizeof(unsigned int)); /* 
> > OVS_PACKET_ATTR_LEN */
> > + + nla_total_size(sizeof(unsigned int)) /* OVS_PACKET_ATTR_LEN 
> > */
> > + + nla_total_size(sizeof(u64)); /* OVS_PACKET_ATTR_HASH */
> >
> >   /* OVS_PACKET_ATTR_USERDATA */
> >   if (upcall_info->userdata)
> > @@ -393,6 +394,7 @@ static int

Re: [ovs-dev] [PATCH net-next v3] net: openvswitch: add hash info to upcall

2019-11-12 Thread Gregory Rose 



On 11/12/2019 7:08 AM, xiangxia.m@gmail.com wrote:

From: Tonghao Zhang 

When using the kernel datapath, the upcall don't
include skb hash info relatived. That will introduce
some problem, because the hash of skb is important
in kernel stack. For example, VXLAN module uses
it to select UDP src port. The tx queue selection
may also use the hash in stack.

Hash is computed in different ways. Hash is random
for a TCP socket, and hash may be computed in hardware,
or software stack. Recalculation hash is not easy.

Hash of TCP socket is computed:
   tcp_v4_connect
 -> sk_set_txhash (is random)

   __tcp_transmit_skb
 -> skb_set_hash_from_sk

There will be one upcall, without information of skb
hash, to ovs-vswitchd, for the first packet of a TCP
session. The rest packets will be processed in Open vSwitch
modules, hash kept. If this tcp session is forward to
VXLAN module, then the UDP src port of first tcp packet
is different from rest packets.

TCP packets may come from the host or dockers, to Open vSwitch.
To fix it, we store the hash info to upcall, and restore hash
when packets sent back.

+---+  +-+
|   Docker/VMs  |  | ovs-vswitchd|
++--+  +-++--+
  |   ^|
  |   ||
  |   |  upcallv restore packet hash (not 
recalculate)
  | +-++--+
  |  tap netdev | |   vxlan module
  +---> +-->  Open vSwitch ko +-->
or internal type| |
+-+

Reported-at: 
https://mail.openvswitch.org/pipermail/ovs-dev/2019-October/364062.html
Signed-off-by: Tonghao Zhang 
---
v3:
* add enum ovs_pkt_hash_types
* avoid duplicate call the skb_get_hash_raw.
* explain why we should fix this problem.
---
  include/uapi/linux/openvswitch.h |  2 ++
  net/openvswitch/datapath.c   | 30 +-
  net/openvswitch/datapath.h   | 12 
  3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index 1887a451c388..e65407c1f366 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -170,6 +170,7 @@ enum ovs_packet_cmd {
   * output port is actually a tunnel port. Contains the output tunnel key
   * extracted from the packet as nested %OVS_TUNNEL_KEY_ATTR_* attributes.
   * @OVS_PACKET_ATTR_MRU: Present for an %OVS_PACKET_CMD_ACTION and
+ * @OVS_PACKET_ATTR_HASH: Packet hash info (e.g. hash, sw_hash and l4_hash in 
skb).
   * @OVS_PACKET_ATTR_LEN: Packet size before truncation.
   * %OVS_PACKET_ATTR_USERSPACE action specify the Maximum received fragment
   * size.
@@ -190,6 +191,7 @@ enum ovs_packet_attr {
OVS_PACKET_ATTR_PROBE,  /* Packet operation is a feature probe,
   error logging should be suppressed. */
OVS_PACKET_ATTR_MRU,/* Maximum received IP fragment size. */
+   OVS_PACKET_ATTR_HASH,   /* Packet hash. */
OVS_PACKET_ATTR_LEN,/* Packet size before truncation. */
__OVS_PACKET_ATTR_MAX
  };


Why do you add the new enum before the last entry OVS_PACKET_ATTR_LEN 
instead of

just adding it to the end of the list?

Just curious.

- Greg


diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 2088619c03f0..b556cf62b77c 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -350,7 +350,8 @@ static size_t upcall_msg_size(const struct dp_upcall_info 
*upcall_info,
size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
+ nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */
+ nla_total_size(ovs_key_attr_size()) /* OVS_PACKET_ATTR_KEY */
-   + nla_total_size(sizeof(unsigned int)); /* OVS_PACKET_ATTR_LEN 
*/
+   + nla_total_size(sizeof(unsigned int)) /* OVS_PACKET_ATTR_LEN */
+   + nla_total_size(sizeof(u64)); /* OVS_PACKET_ATTR_HASH */
  
  	/* OVS_PACKET_ATTR_USERDATA */

if (upcall_info->userdata)
@@ -393,6 +394,7 @@ static int queue_userspace_packet(struct datapath *dp, 
struct sk_buff *skb,
size_t len;
unsigned int hlen;
int err, dp_ifindex;
+   u64 hash;
  
  	dp_ifindex = get_dpifindex(dp);

if (!dp_ifindex)
@@ -504,6 +506,23 @@ static int queue_userspace_packet(struct datapath *dp, 
struct sk_buff *skb,
pad_packet(dp, user_skb);
}
  
+	hash = skb_get_hash_raw(skb);

+   if (hash) {
+   if (skb->sw_hash)
+   hash |= OVS_PACKET_HASH_SW_BIT;
+
+   if (skb->l4_hash)
+   hash |= OVS_PACKET_HASH_L4_BIT;
+
+   if

[ovs-dev] [PATCH net-next v3] net: openvswitch: add hash info to upcall

2019-11-12 Thread xiangxia . m . yue 
From: Tonghao Zhang 

When using the kernel datapath, the upcall don't
include skb hash info relatived. That will introduce
some problem, because the hash of skb is important
in kernel stack. For example, VXLAN module uses
it to select UDP src port. The tx queue selection
may also use the hash in stack.

Hash is computed in different ways. Hash is random
for a TCP socket, and hash may be computed in hardware,
or software stack. Recalculation hash is not easy.

Hash of TCP socket is computed:
  tcp_v4_connect
-> sk_set_txhash (is random)

  __tcp_transmit_skb
-> skb_set_hash_from_sk

There will be one upcall, without information of skb
hash, to ovs-vswitchd, for the first packet of a TCP
session. The rest packets will be processed in Open vSwitch
modules, hash kept. If this tcp session is forward to
VXLAN module, then the UDP src port of first tcp packet
is different from rest packets.

TCP packets may come from the host or dockers, to Open vSwitch.
To fix it, we store the hash info to upcall, and restore hash
when packets sent back.

+---+  +-+
|   Docker/VMs  |  | ovs-vswitchd|
++--+  +-++--+
 |   ^|
 |   ||
 |   |  upcallv restore packet hash (not 
recalculate)
 | +-++--+
 |  tap netdev | |   vxlan module
 +---> +-->  Open vSwitch ko +-->
   or internal type| |
   +-+

Reported-at: 
https://mail.openvswitch.org/pipermail/ovs-dev/2019-October/364062.html
Signed-off-by: Tonghao Zhang 
---
v3:
* add enum ovs_pkt_hash_types
* avoid duplicate call the skb_get_hash_raw.
* explain why we should fix this problem.
---
 include/uapi/linux/openvswitch.h |  2 ++
 net/openvswitch/datapath.c   | 30 +-
 net/openvswitch/datapath.h   | 12 
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index 1887a451c388..e65407c1f366 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -170,6 +170,7 @@ enum ovs_packet_cmd {
  * output port is actually a tunnel port. Contains the output tunnel key
  * extracted from the packet as nested %OVS_TUNNEL_KEY_ATTR_* attributes.
  * @OVS_PACKET_ATTR_MRU: Present for an %OVS_PACKET_CMD_ACTION and
+ * @OVS_PACKET_ATTR_HASH: Packet hash info (e.g. hash, sw_hash and l4_hash in 
skb).
  * @OVS_PACKET_ATTR_LEN: Packet size before truncation.
  * %OVS_PACKET_ATTR_USERSPACE action specify the Maximum received fragment
  * size.
@@ -190,6 +191,7 @@ enum ovs_packet_attr {
OVS_PACKET_ATTR_PROBE,  /* Packet operation is a feature probe,
   error logging should be suppressed. */
OVS_PACKET_ATTR_MRU,/* Maximum received IP fragment size. */
+   OVS_PACKET_ATTR_HASH,   /* Packet hash. */
OVS_PACKET_ATTR_LEN,/* Packet size before truncation. */
__OVS_PACKET_ATTR_MAX
 };
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 2088619c03f0..b556cf62b77c 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -350,7 +350,8 @@ static size_t upcall_msg_size(const struct dp_upcall_info 
*upcall_info,
size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
+ nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */
+ nla_total_size(ovs_key_attr_size()) /* OVS_PACKET_ATTR_KEY */
-   + nla_total_size(sizeof(unsigned int)); /* OVS_PACKET_ATTR_LEN 
*/
+   + nla_total_size(sizeof(unsigned int)) /* OVS_PACKET_ATTR_LEN */
+   + nla_total_size(sizeof(u64)); /* OVS_PACKET_ATTR_HASH */
 
/* OVS_PACKET_ATTR_USERDATA */
if (upcall_info->userdata)
@@ -393,6 +394,7 @@ static int queue_userspace_packet(struct datapath *dp, 
struct sk_buff *skb,
size_t len;
unsigned int hlen;
int err, dp_ifindex;
+   u64 hash;
 
dp_ifindex = get_dpifindex(dp);
if (!dp_ifindex)
@@ -504,6 +506,23 @@ static int queue_userspace_packet(struct datapath *dp, 
struct sk_buff *skb,
pad_packet(dp, user_skb);
}
 
+   hash = skb_get_hash_raw(skb);
+   if (hash) {
+   if (skb->sw_hash)
+   hash |= OVS_PACKET_HASH_SW_BIT;
+
+   if (skb->l4_hash)
+   hash |= OVS_PACKET_HASH_L4_BIT;
+
+   if (nla_put(user_skb, OVS_PACKET_ATTR_HASH,
+   sizeof (u64), )) {
+   err = -ENOBUFS;
+   goto out;
+   }
+
+   pad_packet(dp, user_skb);
+   }
+