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Commit f2a4d086 authored by William Tu's avatar William Tu Committed by David S. Miller
Browse files

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: default avatarWilliam Tu <u9012063@gmail.com>
Cc: Pravin Shelar <pshelar@nicira.com>
Acked-by: default avatarPravin B Shelar <pshelar@ovn.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1578b0a5

include/uapi/linux/openvswitch.h

+6 −0
Original line number Diff line number Diff line
@@ -580,6 +580,10 @@ 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. */

};



/**

 * struct ovs_action_push_mpls - %OVS_ACTION_ATTR_PUSH_MPLS action argument.

 * @mpls_lse: MPLS label stack entry to push.
@@ -703,6 +707,7 @@ 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 +761,7 @@ 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. */

net/openvswitch/actions.c

+36 −4
Original line number Diff line number Diff line
@@ -750,6 +750,14 @@ 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 (unlikely(cutlen > 0)) {

			if (skb->len - cutlen > ETH_HLEN)

				pskb_trim(skb, skb->len - cutlen);

			else

				pskb_trim(skb, ETH_HLEN);

		}



		if (likely(!mru || (skb->len <= mru + ETH_HLEN))) {

			ovs_vport_send(vport, skb);
@@ -775,7 +783,8 @@ 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 +831,7 @@ 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 +841,7 @@ static int sample(struct datapath *dp, struct sk_buff *skb, 
	const struct nlattr *acts_list = NULL;

	const struct nlattr *a;

	int rem;

	u32 cutlen = 0;



	for (a = nla_data(attr), rem = nla_len(attr); rem > 0;

		 a = nla_next(a, &rem)) {
@@ -858,13 +868,24 @@ 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 +1072,7 @@ 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 +1081,18 @@ 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, OVS_CB(skb)->cutlen);

			OVS_CB(skb)->cutlen = 0;

			break;



		case OVS_ACTION_ATTR_HASH:

net/openvswitch/datapath.c

+17 −12
Original line number Diff line number Diff line
@@ -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 @@ void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key) 


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 @@ int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb, 


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;
@@ -461,7 +466,7 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, 
	else

		hlen = skb->len;



	len = upcall_msg_size(upcall_info, hlen);

	len = upcall_msg_size(upcall_info, hlen - cutlen);

	user_skb = genlmsg_new(len, GFP_ATOMIC);

	if (!user_skb) {

		err = -ENOMEM;
@@ -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;

net/openvswitch/datapath.h

+4 −1
Original line number Diff line number Diff line
@@ -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,

net/openvswitch/flow_netlink.c

+9 −0
Original line number Diff line number Diff line
@@ -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_HLEN)

				return -EINVAL;

			break;

		}



		case OVS_ACTION_ATTR_HASH: {

			const struct ovs_action_hash *act_hash = nla_data(a);