In order to be able to function as a Label Edge Router in an MPLS network, it is necessary to be able to take IP packets and impose an MPLS encap and forward them out. The traditional approach of setting up an interface for each "tunnel" endpoint doesn't scale for the common MPLS use-cases where each IP route tends to be assigned a different label as encap.
The solution suggested here for further discussion is to provide the facility to define encap data on a per-nexthop basis using a new netlink attribue, RTA_ENCAP, which would be opaque to the IPv4/IPv6 forwarding code, but interpreted by the virtual interface assigned to the nexthop. A new ipmpls interface type is defined to show the use of this facility to allow IP packets to be imposed with an MPLS encap. However, the facility is designed to be general enough to be used by any encapsulation/tunneling mechanism that has similar requirements of high-scale, high-variation-of-encap. RFC because: - IPv6 side not implemented - struct rtable shouldn't be bloated by pointer+uint - Hasn't been thoroughly tested yet Robert Shearman (3): net: infra for per-nexthop encap data ipv4: storing and retrieval of per-nexthop encap mpls: new ipmpls device for encapsulating IP packets as mpls include/linux/rtnetlink.h | 7 + include/net/dst.h | 11 ++ include/net/dst_ops.h | 2 + include/net/ip_fib.h | 2 + include/net/route.h | 3 + include/net/rtnetlink.h | 11 ++ include/uapi/linux/if_arp.h | 1 + include/uapi/linux/rtnetlink.h | 1 + net/core/rtnetlink.c | 36 ++++++ net/ipv4/fib_frontend.c | 3 + net/ipv4/fib_lookup.h | 2 + net/ipv4/fib_semantics.c | 179 +++++++++++++++++++++++++- net/ipv4/route.c | 24 ++++ net/mpls/Kconfig | 5 + net/mpls/Makefile | 1 + net/mpls/af_mpls.c | 2 + net/mpls/ipmpls.c | 284 +++++++++++++++++++++++++++++++++++++++++ 17 files changed, 572 insertions(+), 2 deletions(-) create mode 100644 net/mpls/ipmpls.c -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
