ovs_nla_get_flow_metadata(9)

💅 ovs_nla_get_flow_metadata 💅

okay so bestie, this is a page from the Kernel API Manual — section 9, kernel devs only, no cap — and it's literally about turning Netlink attributes into a flow key. yes THAT flow key. buckle up 🎀

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✨ NAME ✨

ovs_nla_get_flow_metadata — parses Netlink attributes into a flow key. that's the whole job. iconic honestly 🫶

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🦋 SYNOPSIS 🦋

int ovs_nla_get_flow_metadata (struct net *net , const struct nlattr
*a[OVS_KEY_ATTR_MAX + 1] , u64 attrs , struct sw_flow_key *key , bool
log );

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🌸 ARGUMENTS 🌸

• net — Network namespace. the whole vibe-check context for the network you're in 💫
• a — Array of netlink attributes holding parsed OVS_KEY_ATTR_* Netlink attributes. that's literally the array, bestie, the OVS_KEY_ATTR_* ones, already parsed ✨
• attrs — Bit mask for the netlink attributes included in a. so it's the little checklist of which entries in a are actually in play 🎯
• key — Receives extracted in_port, priority, tun_key, skb_mark and conntrack metadata. she's getting filled in with all the good stuff 💖
• log — Boolean to allow kernel error logging. Normally true, but when probing for feature compatibility this should be passed in as false to suppress unnecessary error logging. so like, false when you're just snooping around asking "u up, do you support this?" and don't want the kernel screaming into the logs 🙈

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👑 DESCRIPTION 👑

so what this does is parse a series of Netlink attributes that form a flow key — and that flow key must take the same form accepted by flow_from_nlattrs, periodt. but it only wants enough of it to get the metadata, i.e. the parts of the flow key that literally cannot be extracted from the packet itself. the packet can't tell you everything, she needs a little help 🫶

⭐ IMPORTANT: this must be called before the packet key fields are filled in key. order matters bestie, do not skip the line 💀

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🌈 SEE ALSO 🌈

• Kernel file ./net/openvswitch/flow_netlink.c
• ovs_nla_get_match(9)

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and that's the whole page, mwah 💋 — brought to you by ./net/openvswitch, dated October 2026, signed ovs_nla_get_flow_metadata(9) 🎀✨🦋