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openvswitch: kernel datapath clone action
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Add 'clone' action to kernel datapath by using existing functions.
When actions within clone don't modify the current flow, the flow
key is not cloned before executing clone actions.

This is a follow up patch for this incomplete work:
https://patchwork.ozlabs.org/patch/722096/

v1 -> v2:
Refactor as advised by reviewer.

Signed-off-by: Yifeng Sun <pkusunyifeng@gmail.com>
Signed-off-by: Andy Zhou <azhou@ovn.org>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Yifeng Sun authored and David S. Miller committed Jul 8, 2018
1 parent 20fbdc3 commit b233504
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5 changes: 5 additions & 0 deletions include/linux/openvswitch.h
Original file line number Diff line number Diff line change
Expand Up @@ -21,4 +21,9 @@

#include <uapi/linux/openvswitch.h>

#define OVS_CLONE_ATTR_EXEC 0 /* Specify an u32 value. When nonzero,
* actions in clone will not change flow
* keys. False otherwise.
*/

#endif /* _LINUX_OPENVSWITCH_H */
3 changes: 3 additions & 0 deletions include/uapi/linux/openvswitch.h
Original file line number Diff line number Diff line change
Expand Up @@ -840,6 +840,8 @@ struct ovs_action_push_eth {
* @OVS_ACTION_ATTR_POP_NSH: pop the outermost NSH header off the packet.
* @OVS_ACTION_ATTR_METER: Run packet through a meter, which may drop the
* packet, or modify the packet (e.g., change the DSCP field).
* @OVS_ACTION_ATTR_CLONE: make a copy of the packet and execute a list of
* actions without affecting the original packet and key.
*
* Only a single header can be set with a single %OVS_ACTION_ATTR_SET. Not all
* fields within a header are modifiable, e.g. the IPv4 protocol and fragment
Expand Down Expand Up @@ -873,6 +875,7 @@ enum ovs_action_attr {
OVS_ACTION_ATTR_PUSH_NSH, /* Nested OVS_NSH_KEY_ATTR_*. */
OVS_ACTION_ATTR_POP_NSH, /* No argument. */
OVS_ACTION_ATTR_METER, /* u32 meter ID. */
OVS_ACTION_ATTR_CLONE, /* Nested OVS_CLONE_ATTR_*. */

__OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted
* from userspace. */
Expand Down
33 changes: 33 additions & 0 deletions net/openvswitch/actions.c
Original file line number Diff line number Diff line change
Expand Up @@ -1057,6 +1057,28 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
clone_flow_key);
}

/* When 'last' is true, clone() should always consume the 'skb'.
* Otherwise, clone() should keep 'skb' intact regardless what
* actions are executed within clone().
*/
static int clone(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key, const struct nlattr *attr,
bool last)
{
struct nlattr *actions;
struct nlattr *clone_arg;
int rem = nla_len(attr);
bool dont_clone_flow_key;

/* The first action is always 'OVS_CLONE_ATTR_ARG'. */
clone_arg = nla_data(attr);
dont_clone_flow_key = nla_get_u32(clone_arg);
actions = nla_next(clone_arg, &rem);

return clone_execute(dp, skb, key, 0, actions, rem, last,
!dont_clone_flow_key);
}

static void execute_hash(struct sk_buff *skb, struct sw_flow_key *key,
const struct nlattr *attr)
{
Expand Down Expand Up @@ -1336,6 +1358,17 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
consume_skb(skb);
return 0;
}
break;

case OVS_ACTION_ATTR_CLONE: {
bool last = nla_is_last(a, rem);

err = clone(dp, skb, key, a, last);
if (last)
return err;

break;
}
}

if (unlikely(err)) {
Expand Down
73 changes: 73 additions & 0 deletions net/openvswitch/flow_netlink.c
Original file line number Diff line number Diff line change
Expand Up @@ -2460,6 +2460,40 @@ static int validate_and_copy_sample(struct net *net, const struct nlattr *attr,
return 0;
}

static int validate_and_copy_clone(struct net *net,
const struct nlattr *attr,
const struct sw_flow_key *key,
struct sw_flow_actions **sfa,
__be16 eth_type, __be16 vlan_tci,
bool log, bool last)
{
int start, err;
u32 exec;

if (nla_len(attr) && nla_len(attr) < NLA_HDRLEN)
return -EINVAL;

start = add_nested_action_start(sfa, OVS_ACTION_ATTR_CLONE, log);
if (start < 0)
return start;

exec = last || !actions_may_change_flow(attr);

err = ovs_nla_add_action(sfa, OVS_CLONE_ATTR_EXEC, &exec,
sizeof(exec), log);
if (err)
return err;

err = __ovs_nla_copy_actions(net, attr, key, sfa,
eth_type, vlan_tci, log);
if (err)
return err;

add_nested_action_end(*sfa, start);

return 0;
}

void ovs_match_init(struct sw_flow_match *match,
struct sw_flow_key *key,
bool reset_key,
Expand Down Expand Up @@ -2849,6 +2883,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
[OVS_ACTION_ATTR_PUSH_NSH] = (u32)-1,
[OVS_ACTION_ATTR_POP_NSH] = 0,
[OVS_ACTION_ATTR_METER] = sizeof(u32),
[OVS_ACTION_ATTR_CLONE] = (u32)-1,
};
const struct ovs_action_push_vlan *vlan;
int type = nla_type(a);
Expand Down Expand Up @@ -3038,6 +3073,18 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
/* Non-existent meters are simply ignored. */
break;

case OVS_ACTION_ATTR_CLONE: {
bool last = nla_is_last(a, rem);

err = validate_and_copy_clone(net, a, key, sfa,
eth_type, vlan_tci,
log, last);
if (err)
return err;
skip_copy = true;
break;
}

default:
OVS_NLERR(log, "Unknown Action type %d", type);
return -EINVAL;
Expand Down Expand Up @@ -3116,6 +3163,26 @@ static int sample_action_to_attr(const struct nlattr *attr,
return err;
}

static int clone_action_to_attr(const struct nlattr *attr,
struct sk_buff *skb)
{
struct nlattr *start;
int err = 0, rem = nla_len(attr);

start = nla_nest_start(skb, OVS_ACTION_ATTR_CLONE);
if (!start)
return -EMSGSIZE;

err = ovs_nla_put_actions(nla_data(attr), rem, skb);

if (err)
nla_nest_cancel(skb, start);
else
nla_nest_end(skb, start);

return err;
}

static int set_action_to_attr(const struct nlattr *a, struct sk_buff *skb)
{
const struct nlattr *ovs_key = nla_data(a);
Expand Down Expand Up @@ -3204,6 +3271,12 @@ int ovs_nla_put_actions(const struct nlattr *attr, int len, struct sk_buff *skb)
return err;
break;

case OVS_ACTION_ATTR_CLONE:
err = clone_action_to_attr(a, skb);
if (err)
return err;
break;

default:
if (nla_put(skb, type, nla_len(a), nla_data(a)))
return -EMSGSIZE;
Expand Down

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