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openvswitch: Add packet len info to upcall.

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The commit f2a4d086ed ("openvswitch: Add packet truncation support.")
introduces packet truncation before sending to userspace upcall receiver.
This patch passes up the skb->len before truncation so that the upcall
receiver knows the original packet size. Potentially this will be used
by sFlow, where OVS translates sFlow config header=N to a sample action,
truncating packet to N byte in kernel datapath. Thus, only N bytes instead
of full-packet size is copied from kernel to userspace, saving the
kernel-to-userspace bandwidth.

Signed-off-by: William Tu <u9012063@gmail.com>
Cc: Pravin Shelar <pshelar@nicira.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
William Tu 2016-06-20 07:26:17 -07:00 committed by David S. Miller
parent 904632a224
commit b95e5928fc
2 changed files with 14 additions and 1 deletions
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2
include/uapi/linux/openvswitch.h
View File

@ -166,6 +166,7 @@ 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_LEN: Packet size before truncation.
* %OVS_PACKET_ATTR_USERSPACE action specify the Maximum received fragment
* size.
*
@ -185,6 +186,7 @@ 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_LEN, /* Packet size before truncation. */
__OVS_PACKET_ATTR_MAX
};

13
net/openvswitch/datapath.c
View File

@ -387,7 +387,8 @@ 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(ovs_key_attr_size()) /* OVS_PACKET_ATTR_KEY */
+ nla_total_size(sizeof(unsigned int)); /* OVS_PACKET_ATTR_LEN */
/* OVS_PACKET_ATTR_USERDATA */
if (upcall_info->userdata)
@ -514,6 +515,16 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
pad_packet(dp, user_skb);
}
/* Add OVS_PACKET_ATTR_LEN when packet is truncated */
if (cutlen > 0) {
if (nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN,
skb->len)) {
err = -ENOBUFS;
goto out;
}
pad_packet(dp, user_skb);
}
/* Only reserve room for attribute header, packet data is added
* in skb_zerocopy() */
if (!(nla = nla_reserve(user_skb, OVS_PACKET_ATTR_PACKET, 0))) {