STRUCT NET_BRIDGE_VLAN(9)

💖 NAME 💖

struct net_bridge_vlan — the per-vlan entry, bestie. one struct, doing double duty ✨

(also hiii, this is from the Kernel API Manual, section 9, and it's giving kernel-internals realness 🫶)

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🌸 SYNOPSIS 🌸

struct net_bridge_vlan {
    struct rhash_head               vnode;
    struct rhash_head               tnode;
    u16 vid;
    u16 flags;
    u16 priv_flags;
    u8 state;
    struct pcpu_sw_netstats __percpu *stats;
    union {
      struct net_bridge       *br;
      struct net_bridge_port  *port;
    };
    union {
      refcount_t refcnt;
      struct net_bridge_vlan  *brvlan;
    };
    struct br_tunnel_info           tinfo;
    union {
      struct net_bridge_mcast         br_mcast_ctx;
      struct net_bridge_mcast_port    port_mcast_ctx;
    };
    u16 msti;
    struct list_head                vlist;
    struct rcu_head                 rcu;
 };

okay look at all those anonymous unions — she's got range 💅

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🎀 Members 🎀

so here's the cast of characters, one by one, no skips, fr fr:

• vnode — rhashtable member. iconic little hash-table citizen 🔥
• tnode — rhashtable member. yes there are two of them, she contains multitudes 😭
• vid — the VLAN id. the whole point, honestly 👑
• flags — bridge vlan flags 🌈
• priv_flags — private (in-kernel) bridge vlan flags 🙈 these are the ones that stay behind the curtain
• state — STP state (e.g. blocking, learning, forwarding). yes she has moods 🦋
• stats — per-cpu VLAN statistics. numbers go brrr per-cpu 🍓
• {unnamed_union} — anonymous. no name, all vibes ✨
  • br — if the MASTER flag is set, this points to a bridge struct
  • port — if the MASTER flag is unset, this points to a port struct
• {unnamed_union} — anonymous again 💀
  • refcnt — if the MASTER flag is set, this is bumped for each port referencing it. every port said "mine" and she keeps count 🫶
  • brvlan — if the MASTER flag is unset, this points to the global per-VLAN context for this VLAN entry
• tinfo — bridge tunnel info. tunnel girlie 🌸
• {unnamed_union} — third anonymous union, she's committed to the bit 💜
  • br_mcast_ctx — if the MASTER flag is set, this is the global vlan multicast context
  • port_mcast_ctx — if the MASTER flag is unset, this is the per-port/vlan multicast context
• msti — if the MASTER flag is set, this holds the VLANs MST instance ⭐
• vlist — sorted list of VLAN entries. she's organized, unlike my sleep schedule 😭
• rcu — used for entry destruction. the goodbye field 💀

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🦋 Description 🦋

okay so the lore: this structure is shared between two whole situations — the global per-VLAN entries living in the bridge rhashtable, and the local per-port per-VLAN entries living in the port's rhashtable. one struct, two households, very main character energy 👑

and here's the crucial part, do not miss it: those union entries should be interpreted depending on the entry flags that are set. like, the flags are the vibe check — they decide which half of the union you're even looking at. read the flags first, bestie, always 🔥

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💅 SEE ALSO 💅

• Kernel file ./net/bridge/br_private.h
• struct net_bridge_vlan_group(9)

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ngl the whole thing hinges on the MASTER flag. respect the flag and you'll be fine 🎀

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and that's the page!! this one came from the kernel tree at ./net/bridge, dated October 2026, and it's struct net_bridge_vlan(9) — go read br_private.h if you wanna see her in the wild 💖✨🫶