cfg80211_ve..._alloc_ucast(9)

okay so we're in the Kernel API Manual, and today's main character is cfg80211_ve..._alloc_ucast(9) — yes, the whole unhinged-looking name, we love her 💅

✨ NAME ✨

cfg80211_vendor_event_alloc_ucast — alloc unicast vendor-specific event skb 🦋

🌸 SYNOPSIS 🌸

struct sk_buff * cfg80211_vendor_event_alloc_ucast (struct wiphy *wiphy
, struct wireless_dev *wdev , unsigned int portid , int approxlen , int
event_idx , gfp_t gfp );

🎀 ARGUMENTS 🎀

• wiphy — the wiphy 🫶
• wdev — the wireless device 🌸
• portid — port ID of the receiver 📬
• approxlen — an upper bound of the length of the data that will be put into the skb 🎀
• event_idx — index of the vendor event in the wiphy's vendor_events 🔥
• gfp — allocation flags 🧚

💅 DESCRIPTION 💅

This function allocates and pre-fills an skb for an event to send to a specific (userland) socket. That socket would previously have been obtained by cfg80211_vendor_cmd_get_sender, and — listen, bestie — the caller MUST take care to register a netlink notifier to see when the socket closes. No cap, that part is serious.

If wdev != NULL, both the ifindex and identifier of the specified wireless device are added to the event message before the vendor data attribute. cute little bonus metadata, slay ✨

When you're done filling the skb, call cfg80211_vendor_event with the skb to send the event. that's the flow, periodt 🦋

🦋 RETURN 🦋

An allocated and pre-filled skb. NULL if any errors happen. 😭

💖 SEE ALSO 💖

okay so before you close this tab, the cross-reference list here is long — like, 350-plus entries long, no exaggeration — and it's basically the whole cfg80211 extended universe. it's giving required reading for the wireless syllabus. i grouped them so your eyes don't glaze over, but every single one is still here, character for character, so you can look up literally any of them with man 9 and get your life together. 🎀

• the origin story — start here, it's where everything comes from: ./include/net/cfg80211.h Introduction(9), Device registration(9)
• the channel / rate / bss-type basics — enum ieee80211_channel_flags(9), struct ieee80211_channel(9), enum ieee80211_rate_flags(9), enum ieee80211_bss_type(9), enum ieee80211_privacy(9), struct ieee80211_rate(9), struct ieee80211_he_obss_pd(9), struct cfg80211_he_bss_color(9)
• capability structs, aka the wifi alphabet soup — struct ieee80211_sta_ht_cap(9), struct ieee80211_sta_vht_cap(9), struct ieee80211_sta_he_cap(9), struct ieee80211_eht_mcs_nss_supp(9), struct ieee80211_sta_eht_cap(9), struct ieee80211_sta_uhr_cap(9), struct ieee80211_sband_iftype_data(9), enum ieee80211_edmg_bw_config(9), struct ieee80211_edmg(9), struct ieee80211_sta_s1g_cap(9), struct ieee80211_supported_band(9)
• sband iftype helpers, the little getters/setters — _ieee80211_set_sband_iftype_data(9), ieee80211_set_sband_iftype_data(9), for_each_sband_iftype_data(9), ieee80211_get_sband_iftype_data(9), ieee80211_get_he_iftype_cap(9), ieee80211_get_he_6ghz_capa(9), ieee80211_get_eht_iftype_cap(9), ieee80211_get_uhr_iftype_cap(9), wiphy_read_of_freq_limits(9)
• Actions and configuration, the section that runs this whole corner — Actions and configuration(9), struct vif_params(9), struct key_params(9), struct cfg80211_chan_def(9), struct cfg80211_tid_cfg(9), struct cfg80211_tid_config(9), struct cfg80211_fils_aad(9), struct cfg80211_set_hw_timestamp(9)
• chandef girlies, respect the channel definition — cfg80211_get_chandef_type(9), cfg80211_chandef_create(9), cfg80211_chandef_identical(9), cfg80211_chandef_is_edmg(9), cfg80211_chandef_is_s1g(9), cfg80211_chandef_compatible(9), nl80211_chan_width_to_mhz(9), cfg80211_chandef_get_width(9), cfg80211_chandef_valid(9), cfg80211_chandef_usable(9), cfg80211_chandef_dfs_required(9), cfg80211_chandef_dfs_usable(9), cfg80211_chandef_dfs_cac_time(9), cfg80211_chandef_primary(9), cfg80211_chandef_npca_valid(9), cfg80211_chandef_add_npca(9), cfg80211_chandef_add_dbe(9), nl80211_send_chandef(9), ieee80211_chandef_max_power(9), cfg80211_chandef_s1g_pri_width(9), cfg80211_any_usable_channels(9)
• survey + crypto + all the AP-side structs — enum survey_info_flags(9), struct survey_info(9), struct cfg80211_crypto_settings(9), struct cfg80211_mbssid_config(9), struct cfg80211_mbssid_elems(9), struct cfg80211_rnr_elems(9), struct cfg80211_beacon_data(9), struct cfg80211_acl_data(9), struct cfg80211_fils_discovery(9), struct cfg80211_unsol_bcast_probe_resp(9), struct cfg80211_s1g_short_beacon(9), struct cfg80211_ap_settings(9), struct cfg80211_ap_update(9), struct cfg80211_csa_settings(9), struct cfg80211_color_change_settings(9), struct iface_combination_params(9)
• station era — params, rates, stats, SAR, mesh, OCB, txq — enum station_parameters_apply_mask(9), struct sta_txpwr(9), struct link_station_parameters(9), struct link_station_del_parameters(9), struct cfg80211_ttlm_params(9), struct station_parameters(9), struct station_del_parameters(9), enum cfg80211_station_type(9), cfg80211_check_station_change(9), enum rate_info_flags(9), enum rate_info_bw(9), struct rate_info(9), enum bss_param_flags(9), struct sta_bss_parameters(9), struct cfg80211_txq_stats(9), struct cfg80211_tid_stats(9), struct link_station_info(9), struct station_info(9), struct cfg80211_sar_sub_specs(9), struct cfg80211_sar_specs(9), struct cfg80211_sar_freq_ranges(9), struct cfg80211_sar_capa(9), cfg80211_get_station(9), enum monitor_flags(9), enum mpath_info_flags(9), struct mpath_info(9), enum wiphy_bss_param_flags(9), struct bss_parameters(9), struct mesh_config(9), struct mesh_setup(9), struct ocb_setup(9), struct ieee80211_txq_params(9)
• Scanning and BSS list handling, the whole scavenger hunt — Scanning and BSS list handling(9), struct cfg80211_ssid(9), struct cfg80211_scan_info(9), struct cfg80211_scan_6ghz_params(9), struct cfg80211_scan_request(9), struct cfg80211_match_set(9), struct cfg80211_sched_scan_plan(9), struct cfg80211_bss_select_adjust(9), struct cfg80211_sched_scan_request(9), enum cfg80211_signal_type(9), struct cfg80211_inform_bss(9), struct cfg80211_bss_ies(9), struct cfg80211_bss(9), ieee80211_bss_get_elem(9), ieee80211_bss_get_ie(9)
• auth, assoc, deauth, disassoc, ibss, connect params — struct cfg80211_auth_request(9), struct cfg80211_assoc_link(9), struct cfg80211_ml_reconf_req(9), enum cfg80211_assoc_req_flags(9), struct cfg80211_assoc_request(9), struct cfg80211_deauth_request(9), struct cfg80211_disassoc_request(9), struct cfg80211_ibss_params(9), struct cfg80211_bss_selection(9), struct cfg80211_connect_params(9), enum cfg80211_connect_params_changed(9)
• wiphy params, pmksa, patterns, wowlan, coalesce, qos — enum wiphy_params_flags(9), struct cfg80211_pmksa(9), struct cfg80211_pkt_pattern(9), struct cfg80211_wowlan_tcp(9), struct cfg80211_wowlan(9), struct cfg80211_coalesce_rules(9), struct cfg80211_coalesce(9), struct cfg80211_wowlan_nd_match(9), struct cfg80211_wowlan_nd_info(9), struct cfg80211_wowlan_wakeup(9), struct cfg80211_gtk_rekey_data(9), struct cfg80211_update_ft_ies_params(9), struct cfg80211_mgmt_tx_params(9), struct cfg80211_dscp_exception(9), struct cfg80211_dscp_range(9), struct cfg80211_qos_map(9)
• NAN time, Neighbor Awareness Networking is such a vibe — Neighbor Awareness Networking (NAN)(9), struct cfg80211_nan_band_config(9), struct cfg80211_nan_conf(9), struct cfg80211_nan_channel(9), struct cfg80211_nan_local_sched(9), struct cfg80211_nan_peer_map(9), struct cfg80211_nan_peer_sched(9), enum cfg80211_nan_conf_changes(9), struct cfg80211_nan_func_filter(9), struct cfg80211_nan_func(9)
• pmk, external auth, FTM/PMSR results and requests, OWE, mgmt frame regs — struct cfg80211_pmk_conf(9), struct cfg80211_external_auth_params(9), struct cfg80211_ftm_responder_stats(9), struct cfg80211_pmsr_ftm_result(9), struct cfg80211_pmsr_result(9), struct cfg80211_pmsr_ftm_request_peer(9), struct cfg80211_pmsr_request_peer(9), struct cfg80211_pmsr_request(9), struct cfg80211_update_owe_info(9), struct mgmt_frame_regs(9)
• the ops table and everything it points at — struct cfg80211_ops(9), enum wiphy_flags(9), struct ieee80211_iface_limit(9), struct ieee80211_iface_combination(9), enum wiphy_wowlan_support_flags(9), struct wiphy_wowlan_support(9), struct wiphy_coalesce_support(9), enum wiphy_vendor_command_flags(9), enum wiphy_opmode_flag(9), struct sta_opmode_info(9), struct wiphy_vendor_command(9), struct wiphy_iftype_ext_capab(9), cfg80211_get_iftype_ext_capa(9), struct cfg80211_pmsr_capabilities(9), struct wiphy_iftype_akm_suites(9), struct wiphy_radio_cfg(9), struct wiphy_radio_freq_range(9), struct wiphy_radio(9), enum wiphy_nan_flags(9), struct wiphy_nan_capa(9)
• the wiphy lifecycle, birth to free (and all the work queues in between) — struct wiphy(9), wiphy_priv(9), priv_to_wiphy(9), set_wiphy_dev(9), wiphy_dev(9), wiphy_name(9), wiphy_new_nm(9), wiphy_new(9), wiphy_register(9), rcu_dereference_wiphy(9), wiphy_dereference(9), get_wiphy_regdom(9), wiphy_unregister(9), wiphy_free(9), wiphy_lock(9), wiphy_unlock(9), wiphy_work_queue(9), wiphy_work_cancel(9), wiphy_work_flush(9), wiphy_delayed_work_queue(9), wiphy_delayed_work_cancel(9), wiphy_delayed_work_flush(9), wiphy_delayed_work_pending(9), wiphy_hrtimer_work_queue(9), wiphy_hrtimer_work_cancel(9), wiphy_hrtimer_work_flush(9), wiphy_hrtimer_work_pending(9)
• wireless_dev and friends — enum ieee80211_ap_reg_power(9), struct wireless_dev(9), wdev_priv(9), wdev_chandef(9)
• Utility functions, the helpful girlies — Utility functions(9), ieee80211_channel_equal(9), ieee80211_channel_to_khz(9), ieee80211_channel_to_freq_khz(9), ieee80211_channel_to_frequency(9), ieee80211_freq_khz_to_channel(9), ieee80211_frequency_to_channel(9), ieee80211_get_channel_khz(9), ieee80211_get_channel(9), cfg80211_channel_is_psc(9), ieee80211_radio_freq_range_valid(9), cfg80211_radio_chandef_valid(9), cfg80211_wdev_channel_allowed(9), ieee80211_get_response_rate(9), ieee80211_mandatory_rates(9), struct ieee80211_radiotap_iterator(9), ieee80211_get_hdrlen_from_skb(9), ieee80211_hdrlen(9), ieee80211_get_mesh_hdrlen(9)
• Data path helpers — 802.3 conversions, A-MSDU, element finding, RNR, defrag — Data path helpers(9), ieee80211_data_to_8023_exthdr(9), ieee80211_data_to_8023(9), ieee80211_is_valid_amsdu(9), ieee80211_amsdu_to_8023s(9), ieee80211_get_8023_tunnel_proto(9), ieee80211_strip_8023_mesh_hdr(9), cfg80211_classify8021d(9), cfg80211_find_elem_match(9), cfg80211_find_ie_match(9), cfg80211_find_elem(9), cfg80211_find_ie(9), cfg80211_find_ext_elem(9), cfg80211_find_ext_ie(9), cfg80211_find_vendor_elem(9), cfg80211_find_vendor_ie(9), enum cfg80211_rnr_iter_ret(9), cfg80211_iter_rnr(9), cfg80211_defragment_element(9), cfg80211_send_layer2_update(9)
• Regulatory enforcement infrastructure — the law, basically — Regulatory enforcement infrastructure(9), regulatory_hint(9), regulatory_set_wiphy_regd(9), regulatory_set_wiphy_regd_sync(9), wiphy_apply_custom_regulatory(9), freq_reg_info(9), reg_initiator_name(9), regulatory_pre_cac_allowed(9), Internal regulatory db functions(9), reg_query_regdb_wmm(9)
• scan done + BSS reporting + the MLME rx/tx family — cfg80211_scan_done(9), cfg80211_sched_scan_results(9), cfg80211_sched_scan_stopped(9), cfg80211_sched_scan_stopped_locked(9), cfg80211_inform_bss_frame_data(9), cfg80211_gen_new_bssid(9), cfg80211_is_element_inherited(9), cfg80211_merge_profile(9), enum cfg80211_bss_frame_type(9), cfg80211_get_ies_channel_number(9), cfg80211_ssid_eq(9), cfg80211_inform_bss_data(9), __cfg80211_get_bss(9), cfg80211_get_bss(9), cfg80211_ref_bss(9), cfg80211_put_bss(9), cfg80211_unlink_bss(9), cfg80211_bss_iter(9), cfg80211_rx_mlme_mgmt(9), cfg80211_auth_timeout(9), struct cfg80211_rx_assoc_resp_data(9), cfg80211_rx_assoc_resp(9), struct cfg80211_assoc_failure(9), cfg80211_assoc_failure(9), cfg80211_tx_mlme_mgmt(9), cfg80211_rx_unprot_mlme_mgmt(9), cfg80211_michael_mic_failure(9), cfg80211_ibss_joined(9), cfg80211_notify_new_peer_candidate(9)
• RFkill, Vendor commands, Test mode — the side quests — RFkill integration(9), wiphy_rfkill_set_hw_state_reason(9), wiphy_rfkill_start_polling(9), wiphy_rfkill_stop_polling(9), Vendor commands(9), cfg80211_vendor_cmd_alloc_reply_skb(9), cfg80211_vendor_cmd_reply(9), cfg80211_vendor_cmd_get_sender(9), cfg80211_vendor_event_alloc(9), cfg80211_vendor_event(9), Test mode(9), cfg80211_testmode_alloc_reply_skb(9), cfg80211_testmode_reply(9), cfg80211_testmode_alloc_event_skb(9), cfg80211_testmode_event(9)
• connect / roam / disconnect notifications + station add/remove — struct cfg80211_fils_resp_params(9), struct cfg80211_connect_resp_params(9), cfg80211_connect_done(9), cfg80211_connect_bss(9), cfg80211_connect_result(9), cfg80211_connect_timeout(9), struct cfg80211_roam_info(9), cfg80211_roamed(9), cfg80211_port_authorized(9), cfg80211_disconnected(9), cfg80211_ready_on_channel(9), cfg80211_remain_on_channel_expired(9), cfg80211_tx_mgmt_expired(9), cfg80211_sinfo_alloc_tid_stats(9), cfg80211_link_sinfo_alloc_tid_stats(9), cfg80211_sinfo_release_content(9), cfg80211_new_sta(9), cfg80211_del_sta_sinfo(9), cfg80211_del_sta(9), cfg80211_conn_failed(9)
• mgmt rx/tx status + control port — struct cfg80211_rx_info(9), cfg80211_rx_mgmt_ext(9), cfg80211_rx_mgmt_khz(9), cfg80211_rx_mgmt(9), struct cfg80211_tx_status(9), cfg80211_mgmt_tx_status_ext(9), cfg80211_mgmt_tx_status(9), cfg80211_control_port_tx_status(9), cfg80211_rx_control_port(9)
• CQM + radar + CAC + gtk rekey + spurious frames + OBSS beacon reports, the notifier finale — cfg80211_cqm_rssi_notify(9), cfg80211_cqm_pktloss_notify(9), cfg80211_cqm_txe_notify(9), cfg80211_cqm_beacon_loss_notify(9), __cfg80211_radar_event(9), cfg80211_sta_opmode_change_notify(9), cfg80211_cac_event(9), cfg80211_background_cac_abort(9), cfg80211_gtk_rekey_notify(9), cfg80211_pmksa_candidate_notify(9), cfg80211_rx_spurious_frame(9), cfg80211_rx_unexpected_4addr_frame(9), cfg80211_probe_status(9), cfg80211_report_obss_beacon_khz(9), cfg80211_report_obss_beacon(9), struct cfg80211_beaconing_check_config(9)

bestie i'm so serious — that list is not decoration. if you're touching anything in here, go read the actual page for it, don't just vibe-guess the semantics. the kernel does not accept "i thought it worked like that" as a valid argument. 😭💀

Okay so the cross-reference list keeps going and honestly it's giving "the group chat keeps adding people to the call" energy 😭 — here's the rest of the crew, in the same order, no cap:

🌸 Regulatory & beaconing besties

• cfg80211_reg_check_beaconing
• cfg80211_reg_can_beacon
• cfg80211_reg_can_beacon_relax

🦋 Channel switch notify girlies

• cfg80211_ch_switch_notify
• cfg80211_ch_switch_started_notify

✨ Operating class / chandef conversion squad

• ieee80211_operating_class_to_band
• ieee80211_operating_class_to_chandef
• ieee80211_chandef_to_operating_class
• ieee80211_chandef_to_khz

💅 Odds, ends, and device registration

• cfg80211_tdls_oper_request
• cfg80211_calculate_bitrate
• cfg80211_unregister_wdev
• cfg80211_register_netdevice
• cfg80211_unregister_netdevice

🎀 Fast transition corner

• struct cfg80211_ft_event_params
• cfg80211_ft_event

🫶 P2P attrs & IE splitting

• cfg80211_get_p2p_attr
• ieee80211_ie_split_ric
• ieee80211_ie_split
• ieee80211_fragment_element

🌈 Wakeup & crit proto

• cfg80211_report_wowlan_wakeup
• cfg80211_crit_proto_stopped

⭐ Channels & combinations

• ieee80211_get_num_supported_channels
• cfg80211_check_combinations
• cfg80211_iter_combinations
• cfg80211_get_radio_idx_by_chan

💀 Stopping things (politely)

• cfg80211_stop_link
• cfg80211_stop_iface
• cfg80211_shutdown_all_interfaces

🔥 Extended feature flags

• wiphy_ext_feature_set
• wiphy_ext_feature_isset

🧚 NAN girlies, part one

• cfg80211_free_nan_func
• struct cfg80211_nan_match_params
• cfg80211_nan_match
• cfg80211_nan_func_terminated
• cfg80211_nan_sched_update_done
• cfg80211_external_auth_request

🍓 PMSR & assorted interface lore

• cfg80211_pmsr_report
• cfg80211_pmsr_complete
• cfg80211_iftype_allowed
• cfg80211_assoc_comeback
• cfg80211_update_owe_info_event
• cfg80211_bss_flush

👑 Colour change committee

• cfg80211_bss_color_notify
• cfg80211_obss_color_collision_notify
• cfg80211_color_change_started_notify
• cfg80211_color_change_aborted_notify
• cfg80211_color_change_notify
• cfg80211_6ghz_power_type

💜 Links, MLO reconf, and channel checks

• cfg80211_links_removed
• struct cfg80211_mlo_reconf_done_data
• cfg80211_mlo_reconf_add_done
• cfg80211_schedule_channels_check
• cfg80211_epcs_changed

🌸 NAN girlies, part two (the sequel)

• cfg80211_next_nan_dw_notif
• cfg80211_nan_cluster_joined
• cfg80211_nan_ulw_update
• cfg80211_nan_channel_evac

🔒 Locked debugfs duo

• wiphy_locked_debugfs_read
• wiphy_locked_debugfs_write

🦋 S1G helpers

• cfg80211_s1g_get_start_freq_khz
• cfg80211_s1g_get_end_freq_khz
• cfg80211_s1g_get_primary_sibling

⭐ And one last icon

• cfg80211_incumbent_signal_notify

---

And that's the whole list, bestie — every single one, not a single name dropped 💖 Go click through whichever one you actually needed, iykyk.

This lil page lives in ./include/net and it's dated October 2026 — so yeah, it's giving "fresh out the kernel" energy 🎀✨ Ttyl! 🫶