On 9/12/22 11:16 AM, Andrea Mayer wrote: > The NEXT-C-SID mechanism described in [1] offers the possibility of > encoding several SRv6 segments within a single 128 bit SID address. Such > a SID address is called a Compressed SID (C-SID) container. In this way, > the length of the SID List can be drastically reduced. > > A SID instantiated with the NEXT-C-SID flavor considers an IPv6 address > logically structured in three main blocks: i) Locator-Block; ii) > Locator-Node Function; iii) Argument. > > C-SID container > +------------------------------------------------------------------+ > | Locator-Block |Loc-Node| Argument | > | |Function| | > +------------------------------------------------------------------+ > <--------- B -----------> <- NF -> <------------- A ---------------> > > (i) The Locator-Block can be any IPv6 prefix available to the provider; > > (ii) The Locator-Node Function represents the node and the function to > be triggered when a packet is received on the node; > > (iii) The Argument carries the remaining C-SIDs in the current C-SID > container. > > The NEXT-C-SID mechanism relies on the "flavors" framework defined in > [2]. The flavors represent additional operations that can modify or > extend a subset of the existing behaviors. > > This patch introduces the support for flavors in SRv6 End behavior > implementing the NEXT-C-SID one. An SRv6 End behavior with NEXT-C-SID > flavor works as an End behavior but it is capable of processing the > compressed SID List encoded in C-SID containers. > > An SRv6 End behavior with NEXT-C-SID flavor can be configured to support > user-provided Locator-Block and Locator-Node Function lengths. In this > implementation, such lengths must be evenly divisible by 8 (i.e. must be > byte-aligned), otherwise the kernel informs the user about invalid > values with a meaningful error code and message through netlink_ext_ack. > > If Locator-Block and/or Locator-Node Function lengths are not provided > by the user during configuration of an SRv6 End behavior instance with > NEXT-C-SID flavor, the kernel will choose their default values i.e., > 32-bit Locator-Block and 16-bit Locator-Node Function. > > [1] - https://datatracker.ietf.org/doc/html/draft-ietf-spring-srv6-srh-compression > [2] - https://datatracker.ietf.org/doc/html/rfc8986 > > Signed-off-by: Andrea Mayer <andrea.mayer@xxxxxxxxxxx> > --- > include/uapi/linux/seg6_local.h | 24 +++ > net/ipv6/seg6_local.c | 335 +++++++++++++++++++++++++++++++- > 2 files changed, 356 insertions(+), 3 deletions(-) > Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
