STRUCT BATADV_FRAG_PACKET(9)

💅 struct batadv_frag_packet(9) 💅

okay so bestie, welcome to the Kernel API Manual entry for struct batadv_frag_packet — literally the little packet wrapper that carries a fragmented packet around. it's giving "I got chopped into pieces and I need to be put back together" energy. let's get into it ✨

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🌸 NAME 🌸

struct batadv_frag_packet — fragmented packet 🧩

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✨ SYNOPSIS ✨

struct batadv_frag_packet {
    __u8 packet_type;
    __u8 version;
    __u8 ttl;
  #if defined(__BIG_ENDIAN_BITFIELD);
    __u8 no:4;
    __u8 priority:3;
    __u8 reserved:1;
  #elif defined(__LITTLE_ENDIAN_BITFIELD);
    __u8 reserved:1;
    __u8 priority:3;
    __u8 no:4;
  #else;
  #error unknownbitfieldendianness";"
  #endif;
    __u8 dest[ETH_ALEN];
    __u8 orig[ETH_ALEN];
    __be16 seqno;
    __be16 total_size;
 };

no cap, those bitfield orderings flip depending on endianness — and if the compiler can't tell which one you're on, you get that #error right in your face 😭

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🎀 Members 🎀

okay so here's the whole cast of characters, main character energy only 👑

• packet_type — the batman-adv packet type, and it's part of the general header (so it's basically the intro card of the packet 🪪)
• version — the batman-adv protocol version, also part of the general header
• ttl — time to live for this packet, again part of the general header. it's literally the packet's little lifespan hourglass ⏳
• no — the fragment number within this sequence. like "which slice of the pizza is this" 🍕
• priority — priority of frame, pulled from ToS IP precedence or 802.1p. highkey the VIP pass 💅
• reserved — a reserved byte for alignment
• reserved — ya, another reserved byte for alignment (it shows up in both bitfield branches, iykyk)
• priority — priority of frame, from ToS IP precedence or 802.1p — yes, again, because of the two endian branches 🌀
• no — fragment number within this sequence — same deal, second branch ✌️
• dest — final destination used when routing fragments. where the pieces are headed 🗺️
• orig — originator of the fragment used when merging the packet. who sent this little piece in the first place 📬
• seqno — sequence identification. the group-chat thread ID fr fr 🧵
• total_size — size of the merged packet, i.e. what you get once all the fragments are stitched back together 🧵✨

quick heads up: reserved, priority, and no each show up twice in the members list because the struct has a big-endian branch and a little-endian branch. not a typo, it's just the vibe check across both worlds 💜

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🦋 SEE ALSO 🦋

the whole friend group, all linked together 🫶 — from the kernel file ./include/uapi/linux/batadv_packet.h:

• batadv_tp_is_error(9)
• enum batadv_packettype(9)
• enum batadv_subtype(9)
• enum batadv_iv_flags(9)
• enum batadv_icmp_packettype(9)
• enum batadv_mcast_flags(9)
• enum batadv_tt_data_flags(9)
• enum batadv_vlan_flags(9)
• enum batadv_bla_claimframe(9)
• enum batadv_tvlv_type(9)
• struct batadv_bla_claim_dst(9)
• struct batadv_ogm_packet(9)
• struct batadv_ogm2_packet(9)
• struct batadv_elp_packet(9)
• struct batadv_icmp_header(9)
• struct batadv_icmp_packet(9)
• struct batadv_icmp_tp_packet(9)
• enum batadv_icmp_tp_subtype(9)
• struct batadv_icmp_packet_rr(9)
• struct batadv_unicast_packet(9)
• struct batadv_unicast_4addr_packet(9)
• struct batadv_bcast_packet(9)
• struct batadv_mcast_packet(9)
• struct batadv_coded_packet(9)
• struct batadv_unicast_tvlv_packet(9)
• struct batadv_tvlv_hdr(9)
• struct batadv_tvlv_gateway_data(9)
• struct batadv_tvlv_tt_vlan_data(9)
• struct batadv_tvlv_tt_data(9)
• struct batadv_tvlv_tt_change(9)
• struct batadv_tvlv_roam_adv(9)
• struct batadv_tvlv_mcast_data(9)
• struct batadv_tvlv_mcast_tracker(9)

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and that's the whole page bestie, you ate that 🍓

signing off from ./include/uapi/linux, dated October 2026 — this was struct batadv_frag_packet(9), slay 💖🎀🦋