__dev_get_by_index(9)

💖 __dev_get_by_index(9) 💖

okay bestie, welcome to this Kernel API Manual page — it's giving “find a network device by its ifindex” energy, and we're gonna read it together. 💅✨

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🌸 NAME 🌸

__dev_get_by_index — find a device by its ifindex. that's the whole assignment, no cap. 🎀

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✨ SYNOPSIS ✨

struct net_device * __dev_get_by_index (struct net *net , int ifindex );

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🎀 ARGUMENTS 🎀

• net — the applicable net namespace. like, which net world we're in, bestie. 🌐
• ifindex — index of device. the little number that IDs it. 🔢

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🦋 DESCRIPTION 🦋

Search for an interface by index. If it finds it, you get a pointer to the device; if not, you get NULL. It's giving “lookup, but make it careful.” 😭💖

The device has not had its reference counter increased, so the caller must be careful about locking. read that again, bestie — no free refcount hug here. 🫶

🔥 Important lock check: the caller must hold the RTNL semaphore. not optional, not a suggestion, periodt. 💀

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🌈 SEE ALSO 🌈

okay bestie, the SEE ALSO section is a whole friend group. The kernel file is ./net/core/dev.c, and here is every reference, no skips:

• dev_add_pack(9), __dev_remove_pack(9)
• dev_remove_pack(9), dev_get_iflink(9), dev_fill_metadata_dst(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_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)

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xoxo, your kernel bestie 🫶 — source/version is ./net/core, dated October 2026. 💖✨