Re: [PATCH net-next v2 3/5] bpf: BPF for lightweight tunnel encapsulation
From: Roopa Prabhu <hidden>
Date: 2016-11-02 13:39:16
On 10/31/16, 5:37 PM, Thomas Graf wrote:
Register two new BPF prog types BPF_PROG_TYPE_LWT_IN and
BPF_PROG_TYPE_LWT_OUT which are invoked if a route contains a
LWT redirection of type LWTUNNEL_ENCAP_BPF.
The separate program types are required because manipulation of
packet data is only allowed on the output and transmit path as
the subsequent dst_input() call path assumes an IP header
validated by ip_rcv(). The BPF programs will be handed an skb
with the L3 header attached and may return one of the following
return codes:
BPF_OK - Continue routing as per nexthop
BPF_DROP - Drop skb and return EPERM
BPF_REDIRECT - Redirect skb to device as per redirect() helper.
(Only valid on lwtunnel_xmit() hook)
The return codes are binary compatible with their TC_ACT_
relatives to ease compatibility.
A new helper bpf_skb_push() is added which allows to preprend an
L2 header in front of the skb, extend the existing L3 header, or
both. This allows to address a wide range of issues:
- Optimize L2 header construction when L2 information is always
static to avoid ARP/NDisc lookup.
- Extend IP header to add additional IP options.
- Perform simple encapsulation where offload is of no concern.
(The existing funtionality to attach a tunnel key to the skb
and redirect to a tunnel net_device to allow for offload
continues to work obviously).
Signed-off-by: Thomas Graf <tgraf@suug.ch>
---
[snip]
quoted hunk ↗ jump to hunk
diff --git a/net/Kconfig b/net/Kconfig index 7b6cd34..7554f12 100644 --- a/net/Kconfig +++ b/net/Kconfig@@ -396,6 +396,7 @@ source "net/nfc/Kconfig" config LWTUNNEL bool "Network light weight tunnels" + depends on IPV6 || IPV6=n ---help--- This feature provides an infrastructure to support light weight tunnels like mpls. There is no netdevice associated with a lightdiff --git a/net/core/Makefile b/net/core/Makefile index d6508c2..a675fd3 100644 --- a/net/core/Makefile +++ b/net/core/Makefile@@ -23,7 +23,7 @@ obj-$(CONFIG_NETWORK_PHY_TIMESTAMPING) += timestamping.o obj-$(CONFIG_NET_PTP_CLASSIFY) += ptp_classifier.o obj-$(CONFIG_CGROUP_NET_PRIO) += netprio_cgroup.o obj-$(CONFIG_CGROUP_NET_CLASSID) += netclassid_cgroup.o -obj-$(CONFIG_LWTUNNEL) += lwtunnel.o +obj-$(CONFIG_LWTUNNEL) += lwtunnel.o lwt_bpf.o
Any reason you want to keep lwt bpf under the main CONFIG_LWTUNNEL infra config ?. since it is defined as yet another plug-gable encap function, seems like it will be better under a separate CONFIG_LWTUNNEL_BPF or CONFIG_LWT_BPF that depends on CONFIG_LWTUNNEL