| Message ID | 1466193177-7656-1-git-send-email-u9012063@gmail.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, Jun 17, 2016 at 12:52 PM, William Tu <u9012063@gmail.com> wrote: > 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 <u9012063@gmail.com> > Cc: Pravin Shelar <pshelar@nicira.com> > --- > v2->v3: > - remove platform specific name. > - fix issue when receiving GSO packet > - remove skblen in struct dp_upcall_info > v1->v2: > - pass skb->len to userspace instead of cutlen > --- > include/uapi/linux/openvswitch.h | 2 ++ > net/openvswitch/datapath.c | 11 ++++++++++- > 2 files changed, 12 insertions(+), 1 deletion(-) > Patch looks good, I just have one minor comment. > diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c > index 6739342..623fc04 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 +515,14 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, > pad_packet(dp, user_skb); > } > > + /* Add OVS_PACKET_ATTR_LEN */ > + if (nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN, > + skb->len)) { > + err = -ENOBUFS; > + goto out; > + } > + pad_packet(dp, user_skb); > + We should only send packet length in case of truncated packet. This would avoid sending this extra attribute in miss flow handling case.
diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h index 8274675..d95a301 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 6739342..623fc04 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 +515,14 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, pad_packet(dp, user_skb); } + /* Add OVS_PACKET_ATTR_LEN */ + 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))) {
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 <u9012063@gmail.com> Cc: Pravin Shelar <pshelar@nicira.com> --- v2->v3: - remove platform specific name. - fix issue when receiving GSO packet - remove skblen in struct dp_upcall_info v1->v2: - pass skb->len to userspace instead of cutlen --- include/uapi/linux/openvswitch.h | 2 ++ net/openvswitch/datapath.c | 11 ++++++++++- 2 files changed, 12 insertions(+), 1 deletion(-)