From b95e5928fcc76d156352570858abdea7b2628efd Mon Sep 17 00:00:00 2001 From: William Tu Date: Mon, 20 Jun 2016 07:26:17 -0700 Subject: [PATCH] openvswitch: Add packet len info to upcall. The commit f2a4d086ed4c ("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 Cc: Pravin Shelar Acked-by: Pravin B Shelar Signed-off-by: David S. Miller --- include/uapi/linux/openvswitch.h | 2 ++ net/openvswitch/datapath.c | 13 ++++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h index 8274675ba9a3..d95a3018f6a1 100644 --- a/include/uapi/linux/openvswitch.h +++ b/include/uapi/linux/openvswitch.h @@ -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 }; diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index 673934295333..524c0fd3078e 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -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))) { -- 2.39.2