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Message-Id: <1465516649-44725-1-git-send-email-u9012063@gmail.com>
Date: Thu, 9 Jun 2016 16:57:29 -0700
From: William Tu <u9012063@...il.com>
To: netdev@...r.kernel.org
Cc: pshelar@....org
Subject: [net-next,v2] openvswitch: Add packet truncation support.
The patch adds a new OVS action, OVS_ACTION_ATTR_TRUNC, in order to
truncate packets. A 'max_len' is added for setting up the maximum
packet size, and a 'cutlen' field is to record the number of bytes
to trim the packet when the packet is outputting to a port, or when
the packet is sent to userspace.
Signed-off-by: William Tu <u9012063@...il.com>
---
v1 -> v2:
- Use 32 bits cutlen and fix unnecessary cutlen initilization.
- Fix cutlen leaks to remaining actions under sample action.
- In queue_userspace_packet, don't extract hlen when using skb_zerocopy.
---
include/uapi/linux/openvswitch.h | 7 +++++++
net/openvswitch/actions.c | 34 ++++++++++++++++++++++++++++++----
net/openvswitch/datapath.c | 27 ++++++++++++++++-----------
net/openvswitch/datapath.h | 5 ++++-
net/openvswitch/flow_netlink.c | 9 +++++++++
net/openvswitch/vport.c | 1 +
6 files changed, 67 insertions(+), 16 deletions(-)
diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index bb0d515..80f8c7c 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -580,6 +580,11 @@ enum ovs_userspace_attr {
#define OVS_USERSPACE_ATTR_MAX (__OVS_USERSPACE_ATTR_MAX - 1)
+struct ovs_action_trunc {
+ uint32_t max_len; /* Max packet size in bytes. */
+};
+#define ETH_MIN_FRAME_LEN ETH_ZLEN
+
/**
* struct ovs_action_push_mpls - %OVS_ACTION_ATTR_PUSH_MPLS action argument.
* @mpls_lse: MPLS label stack entry to push.
@@ -703,6 +708,7 @@ enum ovs_nat_attr {
* enum ovs_action_attr - Action types.
*
* @OVS_ACTION_ATTR_OUTPUT: Output packet to port.
+ * @OVS_ACTION_ATTR_TRUNC: Output packet to port with truncated packet size.
* @OVS_ACTION_ATTR_USERSPACE: Send packet to userspace according to nested
* %OVS_USERSPACE_ATTR_* attributes.
* @OVS_ACTION_ATTR_SET: Replaces the contents of an existing header. The
@@ -756,6 +762,7 @@ enum ovs_action_attr {
* The data must be zero for the unmasked
* bits. */
OVS_ACTION_ATTR_CT, /* Nested OVS_CT_ATTR_* . */
+ OVS_ACTION_ATTR_TRUNC, /* u32 struct ovs_action_trunc. */
__OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted
* from userspace. */
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 9a3eb7a..64dbc80 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -750,6 +750,10 @@ static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port,
if (likely(vport)) {
u16 mru = OVS_CB(skb)->mru;
+ u32 cutlen = OVS_CB(skb)->cutlen;
+
+ if (cutlen > 0)
+ pskb_trim(skb, skb->len - cutlen);
if (likely(!mru || (skb->len <= mru + ETH_HLEN))) {
ovs_vport_send(vport, skb);
@@ -775,7 +779,8 @@ static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port,
static int output_userspace(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key, const struct nlattr *attr,
- const struct nlattr *actions, int actions_len)
+ const struct nlattr *actions, int actions_len,
+ uint32_t cutlen)
{
struct dp_upcall_info upcall;
const struct nlattr *a;
@@ -822,7 +827,7 @@ static int output_userspace(struct datapath *dp, struct sk_buff *skb,
} /* End of switch. */
}
- return ovs_dp_upcall(dp, skb, key, &upcall);
+ return ovs_dp_upcall(dp, skb, key, &upcall, cutlen);
}
static int sample(struct datapath *dp, struct sk_buff *skb,
@@ -832,6 +837,7 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
const struct nlattr *acts_list = NULL;
const struct nlattr *a;
int rem;
+ uint32_t cutlen = 0;
for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
a = nla_next(a, &rem)) {
@@ -858,13 +864,24 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
return 0;
/* The only known usage of sample action is having a single user-space
+ * action, or having a truncate action followed by a single user-space
* action. Treat this usage as a special case.
* The output_userspace() should clone the skb to be sent to the
* user space. This skb will be consumed by its caller.
*/
+ if (unlikely(nla_type(a) == OVS_ACTION_ATTR_TRUNC)) {
+ struct ovs_action_trunc *trunc = nla_data(a);
+
+ if (skb->len > trunc->max_len)
+ cutlen = skb->len - trunc->max_len;
+
+ a = nla_next(a, &rem);
+ }
+
if (likely(nla_type(a) == OVS_ACTION_ATTR_USERSPACE &&
nla_is_last(a, rem)))
- return output_userspace(dp, skb, key, a, actions, actions_len);
+ return output_userspace(dp, skb, key, a, actions,
+ actions_len, cutlen);
skb = skb_clone(skb, GFP_ATOMIC);
if (!skb)
@@ -1051,6 +1068,7 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
if (out_skb)
do_output(dp, out_skb, prev_port, key);
+ OVS_CB(skb)->cutlen = 0;
prev_port = -1;
}
@@ -1059,8 +1077,16 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
prev_port = nla_get_u32(a);
break;
+ case OVS_ACTION_ATTR_TRUNC: {
+ struct ovs_action_trunc *trunc = nla_data(a);
+
+ if (skb->len > trunc->max_len)
+ OVS_CB(skb)->cutlen = skb->len - trunc->max_len;
+ break;
+ }
+
case OVS_ACTION_ATTR_USERSPACE:
- output_userspace(dp, skb, key, a, attr, len);
+ output_userspace(dp, skb, key, a, attr, len, 0);
break;
case OVS_ACTION_ATTR_HASH:
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 856bd8d..26f947e 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -137,10 +137,12 @@ EXPORT_SYMBOL_GPL(lockdep_ovsl_is_held);
static struct vport *new_vport(const struct vport_parms *);
static int queue_gso_packets(struct datapath *dp, struct sk_buff *,
const struct sw_flow_key *,
- const struct dp_upcall_info *);
+ const struct dp_upcall_info *,
+ uint32_t cutlen);
static int queue_userspace_packet(struct datapath *dp, struct sk_buff *,
const struct sw_flow_key *,
- const struct dp_upcall_info *);
+ const struct dp_upcall_info *,
+ uint32_t cutlen);
/* Must be called with rcu_read_lock. */
static struct datapath *get_dp_rcu(struct net *net, int dp_ifindex)
@@ -275,7 +277,7 @@ void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key)
upcall.cmd = OVS_PACKET_CMD_MISS;
upcall.portid = ovs_vport_find_upcall_portid(p, skb);
upcall.mru = OVS_CB(skb)->mru;
- error = ovs_dp_upcall(dp, skb, key, &upcall);
+ error = ovs_dp_upcall(dp, skb, key, &upcall, 0);
if (unlikely(error))
kfree_skb(skb);
else
@@ -300,7 +302,8 @@ out:
int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
const struct sw_flow_key *key,
- const struct dp_upcall_info *upcall_info)
+ const struct dp_upcall_info *upcall_info,
+ uint32_t cutlen)
{
struct dp_stats_percpu *stats;
int err;
@@ -311,9 +314,9 @@ int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
}
if (!skb_is_gso(skb))
- err = queue_userspace_packet(dp, skb, key, upcall_info);
+ err = queue_userspace_packet(dp, skb, key, upcall_info, cutlen);
else
- err = queue_gso_packets(dp, skb, key, upcall_info);
+ err = queue_gso_packets(dp, skb, key, upcall_info, cutlen);
if (err)
goto err;
@@ -331,7 +334,8 @@ err:
static int queue_gso_packets(struct datapath *dp, struct sk_buff *skb,
const struct sw_flow_key *key,
- const struct dp_upcall_info *upcall_info)
+ const struct dp_upcall_info *upcall_info,
+ uint32_t cutlen)
{
unsigned short gso_type = skb_shinfo(skb)->gso_type;
struct sw_flow_key later_key;
@@ -360,7 +364,7 @@ static int queue_gso_packets(struct datapath *dp, struct sk_buff *skb,
if (gso_type & SKB_GSO_UDP && skb != segs)
key = &later_key;
- err = queue_userspace_packet(dp, skb, key, upcall_info);
+ err = queue_userspace_packet(dp, skb, key, upcall_info, cutlen);
if (err)
break;
@@ -416,7 +420,8 @@ static void pad_packet(struct datapath *dp, struct sk_buff *skb)
static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
const struct sw_flow_key *key,
- const struct dp_upcall_info *upcall_info)
+ const struct dp_upcall_info *upcall_info,
+ uint32_t cutlen)
{
struct ovs_header *upcall;
struct sk_buff *nskb = NULL;
@@ -515,9 +520,9 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
err = -ENOBUFS;
goto out;
}
- nla->nla_len = nla_attr_size(skb->len);
+ nla->nla_len = nla_attr_size(skb->len - cutlen);
- err = skb_zerocopy(user_skb, skb, skb->len, hlen);
+ err = skb_zerocopy(user_skb, skb, skb->len - cutlen, hlen);
if (err)
goto out;
diff --git a/net/openvswitch/datapath.h b/net/openvswitch/datapath.h
index 427e39a..ab85c1c 100644
--- a/net/openvswitch/datapath.h
+++ b/net/openvswitch/datapath.h
@@ -100,11 +100,13 @@ struct datapath {
* @input_vport: The original vport packet came in on. This value is cached
* when a packet is received by OVS.
* @mru: The maximum received fragement size; 0 if the packet is not
+ * @cutlen: The number of bytes from the packet end to be removed.
* fragmented.
*/
struct ovs_skb_cb {
struct vport *input_vport;
u16 mru;
+ u32 cutlen;
};
#define OVS_CB(skb) ((struct ovs_skb_cb *)(skb)->cb)
@@ -194,7 +196,8 @@ extern struct genl_family dp_vport_genl_family;
void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key);
void ovs_dp_detach_port(struct vport *);
int ovs_dp_upcall(struct datapath *, struct sk_buff *,
- const struct sw_flow_key *, const struct dp_upcall_info *);
+ const struct sw_flow_key *, const struct dp_upcall_info *,
+ uint32_t cutlen);
const char *ovs_dp_name(const struct datapath *dp);
struct sk_buff *ovs_vport_cmd_build_info(struct vport *, u32 pid, u32 seq,
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index 0bb650f..7bc5405 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -2229,6 +2229,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
[OVS_ACTION_ATTR_SAMPLE] = (u32)-1,
[OVS_ACTION_ATTR_HASH] = sizeof(struct ovs_action_hash),
[OVS_ACTION_ATTR_CT] = (u32)-1,
+ [OVS_ACTION_ATTR_TRUNC] = sizeof(struct ovs_action_trunc),
};
const struct ovs_action_push_vlan *vlan;
int type = nla_type(a);
@@ -2255,6 +2256,14 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
return -EINVAL;
break;
+ case OVS_ACTION_ATTR_TRUNC: {
+ const struct ovs_action_trunc *trunc = nla_data(a);
+
+ if (trunc->max_len < ETH_MIN_FRAME_LEN)
+ return -EINVAL;
+ break;
+ }
+
case OVS_ACTION_ATTR_HASH: {
const struct ovs_action_hash *act_hash = nla_data(a);
diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
index 31cbc8c..6b21fd0 100644
--- a/net/openvswitch/vport.c
+++ b/net/openvswitch/vport.c
@@ -444,6 +444,7 @@ int ovs_vport_receive(struct vport *vport, struct sk_buff *skb,
OVS_CB(skb)->input_vport = vport;
OVS_CB(skb)->mru = 0;
+ OVS_CB(skb)->cutlen = 0;
if (unlikely(dev_net(skb->dev) != ovs_dp_get_net(vport->dp))) {
u32 mark;
--
2.5.0
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