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Donald Hunter authored
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 Reviewed-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Donald Hunter <donald.hunter@gmail.com> Link: https://lore.kernel.org/r/20231215093720.18774-3-donald.hunter@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>
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