dev_fill_metadata_dst(9)

💅 dev_fill_metadata_dst — a Kernel API Manual moment (section 9, bestie)

okay so this vibe is from the kernel API manual, section 9 — like, the section for kernel routines, iykyk. and the whole thing is about ONE tiny little function that does a very specific slay. let's get into it 🩷

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✨ NAME ✨

dev_fill_metadata_dst — literally just "Retrieve tunnel egress information." that's the whole assignment. periodt.

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🌸 SYNOPSIS 🌸

int dev_fill_metadata_dst (struct net_device *dev , struct sk_buff *skb
);

it returns an int, takes a struct net_device * and a struct sk_buff *, and that's the cast. no notes 💅

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🎀 ARGUMENTS 🎀

• dev — the targeted interface. the one we're pointing at 👉🦋
• skb — The packet. the actual lil guy we're doing this to 📦✨

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🧚 DESCRIPTION 🧚

so here's the lore: for better visibility of tunnel traffic, OVS needs to retrieve egress tunnel information for a packet. that's it, that's the reason. the following API allows the user to get this info 🙌

like the whole point of this function is that OVS wants to see what's coming out of the tunnel, and this is the lil doorway that gives it that info. no cap, that's the entire description — it's short but it's iconic 👑

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🔥 SEE ALSO 🔥

kernel file ./net/core/dev.c — and bestie, buckle up, because this list is LONG. like, genuinely long. i'm not skipping a single one, we're doing the full roll call 🌈:

dev_add_pack(9), __dev_remove_pack(9), dev_remove_pack(9), dev_get_iflink(9), netdev_napi_by_id_lock(9), __dev_get_by_name(9), dev_get_by_name_rcu(9), netdev_get_by_name(9), __dev_get_by_index(9), dev_get_by_index_rcu(9), netdev_get_by_index(9), dev_get_by_napi_id(9), netdev_get_by_index_lock(9), netdev_get_name(9), dev_getbyhwaddr_rcu(9), dev_getbyhwaddr(9), netdev_get_by_flags_rcu(9), dev_valid_name(9), __dev_alloc_name(9), dev_alloc_name(9), dev_get_alias(9), netdev_features_change(9), __netdev_notify_peers(9), netdev_notify_peers(9), dev_disable_gro_hw(9), register_netdevice_notifier(9), unregister_netdevice_notifier(9), register_netdevice_notifier_net(9), unregister_netdevice_notifier_net(9), call_netdevice_notifiers_info(9), call_netdevice_notifiers_info_robust(9), call_netdevice_notifiers(9), call_netdevice_notifiers_mtu(9), dev_forward_skb(9), dev_nit_active_rcu(9), netif_setup_tc(9), netif_set_real_num_rx_queues(9), netif_set_real_num_queues(9), netif_set_tso_max_size(9), netif_set_tso_max_segs(9), netif_inherit_tso_max(9), netif_get_num_default_rss_queues(9), netif_device_detach(9), netif_device_attach(9), dev_loopback_xmit(9), __dev_queue_xmit(9), rps_flow_is_active(9), rps_may_expire_flow(9), __netif_rx(9), netif_rx(9), netdev_is_rx_handler_busy(9), netdev_rx_handler_register(9), netdev_rx_handler_unregister(9), netif_receive_skb_core(9), netif_receive_skb(9), netif_receive_skb_list(9), __napi_schedule(9), napi_schedule_prep(9), __napi_schedule_irqoff(9), netif_threaded_enable(9), netif_queue_set_napi(9), napi_disable(9), napi_enable(9), netdev_has_upper_dev(9), netdev_has_upper_dev_all_rcu(9), netdev_has_any_upper_dev(9), netdev_master_upper_dev_get(9), netdev_has_any_lower_dev(9), netdev_upper_get_next_dev_rcu(9), netdev_lower_get_next_private(9), netdev_lower_get_next_private_rcu(9), netdev_lower_get_next(9), netdev_lower_get_first_private_rcu(9), netdev_master_upper_dev_get_rcu(9), netdev_upper_dev_link(9), netdev_master_upper_dev_link(9), netdev_upper_dev_unlink(9), netdev_bonding_info_change(9), netdev_get_xmit_slave(9), netdev_sk_get_lowest_dev(9), netdev_lower_state_changed(9), netif_get_flags(9), netif_set_mtu_ext(9), netif_pre_changeaddr_notify(9), dev_get_phys_port_id(9), dev_get_phys_port_name(9), netif_get_port_parent_id(9), netdev_port_same_parent_id(9), netdev_change_proto_down_reason_locked(9), dev_change_xdp_fd(9), dev_index_reserve(9), netdev_update_features(9), netdev_change_features(9), netif_stacked_transfer_operstate(9), register_netdevice(9), register_netdev(9), netdev_wait_allrefs_any(9), dev_get_stats(9), dev_fetch_sw_netstats(9), dev_get_tstats64(9), netdev_sw_irq_coalesce_default_on(9), alloc_netdev_mqs(9), free_netdev(9), alloc_netdev_dummy(9), synchronize_net(9), unregister_netdevice_queue(9), unregister_netdevice_many(9), unregister_netdev(9), netdev_increment_features(9), netdev_compute_master_upper_features(9), netdev_drivername(9)

like… that's the whole friend group right there. every single one of them showed up to the party 💜🫶

ngl, that SEE ALSO list is giving "read the whole dev.c file while you're at it" energy 😭 but honestly? valid.

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okay that's the page!! and for the lil sign-off: this one lives in the source tree at ./net/core, and it's dated October 2026 — a whole future date, main character energy honestly 🔮⭐ mwah, go read your kernel source bestie, ily, bye 💖🎀🦋