Re: [iproute2-next v2] seg6: add support for flavors in SRv6 End* behaviors

[David Ahern <dsahern@kernel.org>]

On 9/12/22 11:39 AM, Paolo Lungaroni wrote:
> As described in RFC 8986 [1], processing operations carried out by SRv6
> End, End.X and End.T (End* for short) behaviors can be modified or
> extended using the "flavors" mechanism. This patch adds the support for
> PSP,USP,USD flavors (defined in [1]) and for NEXT-C-SID flavor (defined
> in [2]) in SRv6 End* behaviors. Specifically, we add a new optional
> attribute named "flavors" that can be leveraged by the user to enable
> specific flavors while creating an SRv6 End* behavior instance.
> Multiple flavors can be specified together by separating them using
> commas.
> 
> If a specific flavor (or a combination of flavors) is not supported by the
> underlying Linux kernel, an error message is reported to the user and the
> creation of the specific behavior instance is aborted.
> 
> When the flavors attribute is omitted, the regular SRv6 End* behavior is
> performed.
> 
> Flavors such as PSP, USP and USD do not accept additional configuration
> attributes. Conversely, the NEXT-C-SID flavor can be configured to support
> user-provided Locator-Block and Locator-Node Function lengths using,
> respectively, the lblen and the nflen attributes.
> 
> Both lblen and nflen values must be evenly divisible by 8 and their sum
> must not exceed 128 bit (i.e. the C-SID container size).
> 
> If the lblen attribute is omitted, the default value chosen by the Linux
> kernel is 32-bit. If the nflen attribute is omitted, the default value
> chosen by the Linux kernel is 16-bit.
> 
> Some examples:
> ip -6 route add 2001:db8::1 encap seg6local action End flavors next-csid dev eth0
> ip -6 route add 2001:db8::2 encap seg6local action End flavors next-csid lblen 48 nflen 16 dev eth0
> 
> Standard Output:
> ip -6 route show 2001:db8::2
> 2001:db8::2  encap seg6local action End flavors next-csid lblen 48 nflen 16 dev eth0 metric 1024 pref medium
> 
> JSON Output:
> ip -6 -j -p route show 2001:db8::2
> [ {
>         "dst": "2001:db8::2",
>         "encap": "seg6local",
>         "action": "End",
>         "flavors": [ "next-csid" ],
>         "lblen": 48,
>         "nflen": 16,
>         "dev": "eth0",
>         "metric": 1024,
>         "flags": [ ],
>         "pref": "medium"
> } ]
> 
> [1] - https://datatracker.ietf.org/doc/html/rfc8986
> [2] - https://datatracker.ietf.org/doc/html/draft-ietf-spring-srv6-srh-compression
> 
> Signed-off-by: Paolo Lungaroni <paolo.lungaroni@uniroma2.it>
> ---
>  include/uapi/linux/seg6_local.h |  24 +++++
>  ip/iproute.c                    |   4 +-
>  ip/iproute_lwtunnel.c           | 186 +++++++++++++++++++++++++++++++-
>  man/man8/ip-route.8.in          |  71 +++++++++++-
>  4 files changed, 281 insertions(+), 4 deletions(-)
> 

applied to iproute2-next. Thanks