| Message ID | 20231130214959.27377-3-donald.hunter@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | tools/net/ynl: Add 'sub-message' support to ynl | expand |
On Thu, 30 Nov 2023 21:49:54 +0000 Donald Hunter wrote: > Add a 'sub-message' attribute type with a selector that supports > polymorphic attribute formats for raw netlink families like tc. > > A sub-message attribute uses the value of another attribute as a > selector key to choose the right sub-message format. For example if the > following attribute has already been decoded: > > { "kind": "gre" } > > and we encounter the following attribute spec: > > - > name: data > type: sub-message > sub-message: linkinfo-data-msg > selector: kind > > Then we look for a sub-message definition called 'linkinfo-data-msg' and > use the value of the 'kind' attribute i.e. 'gre' as the key to choose > the correct format for the sub-message: > > sub-messages: > name: linkinfo-data-msg > formats: > - > value: bridge > attribute-set: linkinfo-bridge-attrs > - > value: gre > attribute-set: linkinfo-gre-attrs > - > value: geneve > attribute-set: linkinfo-geneve-attrs > > This would decode the attribute value as a sub-message with the > attribute-set called 'linkinfo-gre-attrs' as the attribute space. > > A sub-message can have an optional 'fixed-header' followed by zero or > more attributes from an attribute-set. For example the following > 'tc-options-msg' sub-message defines message formats that use a mixture > of fixed-header, attribute-set or both together: > > sub-messages: > - > name: tc-options-msg > formats: > - > value: bfifo > fixed-header: tc-fifo-qopt > - > value: cake > attribute-set: tc-cake-attrs > - > value: netem > fixed-header: tc-netem-qopt > attribute-set: tc-netem-attrs SGTM, could you add all the info from the commit message somewhere in the documentation? Perhaps a new section at the end of Documentation/userspace-api/netlink/specs.rst > @@ -261,6 +262,17 @@ properties: > description: Name of the struct type used for the attribute. > type: string > # End genetlink-legacy > + # Start netlink-raw > + sub-message: > + description: > + Name of the sub-message definition to use for the attribute. > + type: string > + selector: > + description: > + Name of the attribute to use for dynamic selection of sub-message > + format specifier. > + type: string We can leave it for later either way, but have you seen any selectors which would key on an integer, rather than a string?
Jakub Kicinski <kuba@kernel.org> writes: > > SGTM, could you add all the info from the commit message somewhere > in the documentation? Perhaps a new section at the end of > Documentation/userspace-api/netlink/specs.rst Ack, will do. >> @@ -261,6 +262,17 @@ properties: >> description: Name of the struct type used for the attribute. >> type: string >> # End genetlink-legacy >> + # Start netlink-raw >> + sub-message: >> + description: >> + Name of the sub-message definition to use for the attribute. >> + type: string >> + selector: >> + description: >> + Name of the attribute to use for dynamic selection of sub-message >> + format specifier. >> + type: string > > We can leave it for later either way, but have you seen any selectors > which would key on an integer, rather than a string? From what I have seen, I am fairly sure it's always going to be a string. (famous last words)
diff --git a/Documentation/netlink/netlink-raw.yaml b/Documentation/netlink/netlink-raw.yaml index ad5395040765..26203282422f 100644 --- a/Documentation/netlink/netlink-raw.yaml +++ b/Documentation/netlink/netlink-raw.yaml @@ -202,7 +202,8 @@ properties: description: The netlink attribute type enum: [ unused, pad, flag, binary, bitfield32, u8, u16, u32, u64, s8, s16, s32, s64, - string, nest, array-nest, nest-type-value ] + string, nest, array-nest, nest-type-value, + sub-message ] doc: description: Documentation of the attribute. type: string @@ -261,6 +262,17 @@ properties: description: Name of the struct type used for the attribute. type: string # End genetlink-legacy + # Start netlink-raw + sub-message: + description: + Name of the sub-message definition to use for the attribute. + type: string + selector: + description: + Name of the attribute to use for dynamic selection of sub-message + format specifier. + type: string + # End netlink-raw # Make sure name-prefix does not appear in subsets (subsets inherit naming) dependencies: @@ -283,6 +295,43 @@ properties: items: required: [ type ] + # Start netlink-raw + sub-messages: + description: Definition of sub message attributes + type: array + items: + type: object + additionalProperties: False + required: [ name, formats ] + properties: + name: + description: Name of the sub-message definition + type: string + formats: + description: Dynamically selected format specifiers + type: array + items: + type: object + additionalProperties: False + required: [ value ] + properties: + value: + description: + Value to match for dynamic selection of sub-message format + specifier. + type: string + fixed-header: + description: + Name of the struct definition to use as the fixed header + for the sub message. + type: string + attribute-set: + description: + Name of the attribute space from which to resolve attributes + in the sub message. + type: string + # End netlink-raw + operations: description: Operations supported by the protocol. type: object
Add a 'sub-message' attribute type with a selector that supports polymorphic attribute formats for raw netlink families like tc. A sub-message attribute uses the value of another attribute as a selector key to choose the right sub-message format. For example if the following attribute has already been decoded: { "kind": "gre" } and we encounter the following attribute spec: - name: data type: sub-message sub-message: linkinfo-data-msg selector: kind Then we look for a sub-message definition called 'linkinfo-data-msg' and use the value of the 'kind' attribute i.e. 'gre' as the key to choose the correct format for the sub-message: sub-messages: name: linkinfo-data-msg formats: - value: bridge attribute-set: linkinfo-bridge-attrs - value: gre attribute-set: linkinfo-gre-attrs - value: geneve attribute-set: linkinfo-geneve-attrs This would decode the attribute value as a sub-message with the attribute-set called 'linkinfo-gre-attrs' as the attribute space. A sub-message can have an optional 'fixed-header' followed by zero or more attributes from an attribute-set. For example the following 'tc-options-msg' sub-message defines message formats that use a mixture of fixed-header, attribute-set or both together: sub-messages: - name: tc-options-msg formats: - value: bfifo fixed-header: tc-fifo-qopt - value: cake attribute-set: tc-cake-attrs - value: netem fixed-header: tc-netem-qopt attribute-set: tc-netem-attrs Signed-off-by: Donald Hunter <donald.hunter@gmail.com> --- Documentation/netlink/netlink-raw.yaml | 51 +++++++++++++++++++++++++- 1 file changed, 50 insertions(+), 1 deletion(-)