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Justin Iurman says: ==================== Support for the IOAM Pre-allocated Trace with IPv6 v5: - Refine types, min/max and default values for new sysctls - Introduce a "_wide" sysctl for each "ioam6_id" sysctl - Add more validation on headers before processing data - RCU for sc <> ns pointers + appropriate accessors - Generic Netlink policies are now per op, not per family anymore - Address other comments/remarks from Jakub (thanks again) - Revert "__packed" to "__attribute__((packed))" for uapi headers - Add tests to cover the functionality added, as requested by David Ahern v4: - Address warnings from checkpatch (ignore errors related to unnamed bitfields in the first patch) - Use of hweight32 (thanks Jakub) - Remove inline keyword from static functions in C files and let the compiler decide what to do (thanks Jakub) v3: - Fix warning "unused label 'out_unregister_genl'" by adding conditional macro - Fix lwtunnel output redirect bug: dst cache useless in this case, use orig_output instead v2: - Fix warning with static for __ioam6_fill_trace_data - Fix sparse warning with __force when casting __be64 to __be32 - Fix unchecked dereference when removing IOAM namespaces or schemas - exthdrs.c: Don't drop by default (now: ignore) to match the act bits "00" - Add control plane support for the inline insertion (lwtunnel) - Provide uapi structures - Use __net_timestamp if skb->tstamp is empty - Add note about the temporary IANA allocation - Remove support for "removable" TLVs - Remove support for virtual/anonymous tunnel decapsulation In-situ Operations, Administration, and Maintenance (IOAM) records operational and telemetry information in a packet while it traverses a path between two points in an IOAM domain. It is defined in draft-ietf-ippm-ioam-data [1]. IOAM data fields can be encapsulated into a variety of protocols. The IPv6 encapsulation is defined in draft-ietf-ippm-ioam-ipv6-options [2], via extension headers. IOAM can be used to complement OAM mechanisms based on e.g. ICMP or other types of probe packets. This patchset implements support for the Pre-allocated Trace, carried by a Hop-by-Hop. Therefore, a new IPv6 Hop-by-Hop TLV option is introduced, see IANA [3]. The three other IOAM options are not included in this patchset (Incremental Trace, Proof-of-Transit and Edge-to-Edge). The main idea behind the IOAM Pre-allocated Trace is that a node pre-allocates some room in packets for IOAM data. Then, each IOAM node on the path will insert its data. There exist several interesting use- cases, e.g. Fast failure detection/isolation or Smart service selection. Another killer use-case is what we have called Cross-Layer Telemetry, see the demo video on its repository [4], that aims to make the entire stack (L2/L3 -> L7) visible for distributed tracing tools (e.g. Jaeger), instead of the current L5 -> L7 limited view. So, basically, this is a nice feature for the Linux Kernel. This patchset also provides support for the control plane part, but only for the inline insertion (host-to-host use case), through lightweight tunnels. Indeed, for in-transit traffic, the solution is to have an IPv6-in-IPv6 encapsulation, which brings some difficulties and still requires a little bit of work and discussion (ie anonymous tunnel decapsulation and multi egress resolution). - Patch 1: IPv6 IOAM headers definition - Patch 2: Data plane support for Pre-allocated Trace - Patch 3: IOAM Generic Netlink API - Patch 4: Support for IOAM injection with lwtunnels - Patch 5: Documentation for new IOAM sysctls - Patch 6: Test for the IOAM insertion with IPv6 [1] https://tools.ietf.org/html/draft-ietf-ippm-ioam-data [2] https://tools.ietf.org/html/draft-ietf-ippm-ioam-ipv6-options [3] https://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml#ipv6-parameters-2 [4] https://github.com/iurmanj/cross-layer-telemetry ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
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