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-09 [1]. IOAM data fields can be encapsulated into a variety of protocols. The IPv6 encapsulation is defined in draft-ietf-ippm-ioam-ipv6-options-01 [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. IOAM options must be 4n-aligned. Here is how a Hop-by-Hop looks like with IOAM: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next header | Hdr Ext Len | Padding | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Opt Data Len | Reserved | IOAM Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Namespace-ID | NodeLen | Flags | RemainingLen| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IOAM-Trace-Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ | | | | node data [0] | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ D | | a | node data [1] | t | | a +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ... ~ S +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ p | | a | node data [n-1] | c | | e +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | node data [n] | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+ Namespace-ID represents an IOAM namespace identifier, not to be confused with Linux namespaces. IOAM namespaces add further context to IOAM options and associated data, and allow devices which are IOAM capable to determine whether IOAM needs to be processed, updated or removed. They can also be used by an operator to distinguish different operational domains or to identify different sets of devices. Other fields are also explained in [1] and [2]. This patchset does not provide support for the control plane part, ie the IOAM encapsulation or inline insertion (ingress node behavior). It will come as another patch since some design choices still need to be discussed (talk @ Netdev 0x14). Globally, this patchset contains: - Patch 1-3: Data plane support for the IOAM Pre-allocated Trace - Patch 4: Generic Netlink to configure IOAM from userspace (iproute2) - Patch 5: IOAM sysctls documentation [1] https://tools.ietf.org/html/draft-ietf-ippm-ioam-data-09 [2] https://tools.ietf.org/html/draft-ietf-ippm-ioam-ipv6-options-01 [3] https://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml#ipv6-parameters-2 [4] https://github.com/iurmanj/cross-layer-telemetry Justin Iurman (5): ipv6: eh: Introduce removable TLVs ipv6: IOAM tunnel decapsulation ipv6: ioam: Data plane support for Pre-allocated Trace ipv6: ioam: Generic Netlink to configure IOAM ipv6: ioam: Documentation for new IOAM sysctls Documentation/networking/ioam6-sysctl.rst | 20 + Documentation/networking/ip-sysctl.rst | 5 + include/linux/ioam6.h | 7 + include/linux/ipv6.h | 3 + include/net/ioam6.h | 98 +++ include/net/netns/ipv6.h | 2 + include/uapi/linux/in6.h | 1 + include/uapi/linux/ioam6.h | 43 ++ include/uapi/linux/ipv6.h | 2 + net/ipv6/Makefile | 2 +- net/ipv6/addrconf.c | 20 + net/ipv6/af_inet6.c | 7 + net/ipv6/exthdrs.c | 201 +++++- net/ipv6/ioam6.c | 839 ++++++++++++++++++++++ net/ipv6/ip6_input.c | 22 + net/ipv6/sysctl_net_ipv6.c | 7 + 16 files changed, 1252 insertions(+), 27 deletions(-) create mode 100644 Documentation/networking/ioam6-sysctl.rst create mode 100644 include/linux/ioam6.h create mode 100644 include/net/ioam6.h create mode 100644 include/uapi/linux/ioam6.h create mode 100644 net/ipv6/ioam6.c -- 2.17.1
