DATA MESSAGES(9)

💌 DATA MESSAGES (9) 💌

okay bestie, buckle up — this is one of the kernel API manual pages, from the Kernel API Manual, no less. it's giving "networking lore" and honestly? we're seated. 🪑

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✨ NAME ✨

Data messages — the whole vibe of how data packets travel between the host and CSME, explained so you actually get it. 💅

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🌸 DESCRIPTION 🌸

okay so here's the tea ☕: data messages are not allowed to just chill on the same queue as everything else. nope. they have to be sent and received on a separate queue in the shared memory. separate. queue. periodt. 💀

highkey the star of the show is SAP_MSG_DATA_PACKET — almost all the data messages use it, and it pulls double duty like a true main character 👑:

• packets sent by CSME to the host, which the host then sends to the AP 🛫
• packets received from the AP that the host sends on over to CSME 🛬

both directions, same message type. efficient! iconic! we love to see it. ✨

now, how does the host even know what to forward? 🧐 CSME sends filters to the host, and those filters are literally CSME being like "hey bestie, these are the inbound packets you gotta send me." the host receives those filters as a SAP_MSG_NOTIF_CSME_FILTERS command. 🎀 super straightforward.

so what's the only outbound traffic that has to go to CSME? 🥁🥁🥁 the DHCP packets. that's it, that's the list. and ngl those specific packets must use the SAP_MSG_CB_DATA_PACKET message — not the other one, don't mix them up, that's the rule. 💯

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🦋 SEE ALSO 🦋

okay this list is long — like, genuinely committed. but every single one is here because i would never do you dirty like that 🫶:

• the kernel file ./drivers/net/wireless/intel/iwlwifi/mei/sap.h 📁
• Introduction(9)
• Initial Handshake(9)
• Host and driver state messages(9)
• Ownership(9)
• Ownership transfer(9)
• enum iwl_sap_me_msg_id(9)
• struct iwl_sap_me_msg_hdr(9)
• struct iwl_sap_me_msg_start(9)
• struct iwl_sap_me_msg_start_ok(9)
• enum iwl_sap_msg(9)
• struct iwl_sap_hdr(9)
• struct iwl_sap_msg_dw(9)
• enum iwl_sap_nic_owner(9)
• enum iwl_sap_wifi_cipher_alg(9)
• struct iwl_sap_notif_connection_info(9)
• enum iwl_sap_scan_request(9)
• struct iwl_sap_notif_conn_status(9)
• enum iwl_sap_radio_state_bitmap(9)
• enum iwl_sap_notif_host_suspends_bitmap(9)
• struct iwl_sap_notif_country_code(9)
• struct iwl_sap_notif_host_link_up(9)
• enum iwl_sap_notif_link_down_type(9)
• struct iwl_sap_notif_host_link_down(9)
• struct iwl_sap_notif_host_nic_info(9)
• struct iwl_sap_notif_dw(9)
• struct iwl_sap_notif_sar_limits(9)
• enum iwl_sap_nvm_caps(9)
• struct iwl_sap_nvm(9)
• enum iwl_sap_eth_filter_flags(9)
• struct iwl_sap_eth_filter(9)
• enum iwl_sap_flex_filter_flags(9)
• struct iwl_sap_flex_filter(9)
• enum iwl_sap_ipv4_filter_flags(9)
• struct iwl_sap_ipv4_filter(9)
• enum iwl_sap_ipv6_filter_flags(9)
• struct iwl_sap_ipv6_filter(9)
• enum iwl_sap_icmpv6_filter_flags(9)
• enum iwl_sap_vlan_filter_flags(9)
• struct iwl_sap_oob_filters(9)
• struct iwl_sap_csme_filters(9)
• struct iwl_sap_cb_data(9)
• struct iwl_sap_pldr_data(9)
• enum iwl_sap_pldr_status(9)

like i said. committed. 💀✨

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lowkey important reminder: that filter business isn't optional flavor text — CSME tells the host what to forward, and the host has to actually respect it. iykyk 🧚

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that's the whole page, bestie — every flag, every struct, every (9) accounted for, no cap. 🌈

this lil gem comes from the source file ./drivers/net/wireless/intel/i... (yes it's truncated in the original, not my fault 😭) and it's dated October 2026. stay hydrated, read your kernel headers, and slay the day. 💖🎀🦋🌸💅