STRUCT MR_TABLE(9)

🌸 NAME 🌸

struct mr_table — a multicast routing table, bestie 💖 (and yes, it's a 9 — kernel API manual, section 9, we're in the big leagues now)

✨ SYNOPSIS ✨

struct mr_table {
    struct rcu_work         work;
    struct list_head        list;
    possible_net_t net;
    struct mr_table_ops     ops;
    u32 id;
    struct sock *mroute_sk;
    struct timer_list       ipmr_expire_timer;
    struct list_head        mfc_unres_queue;
    struct vif_device       vif_table[MAXVIFS];
    struct rhltable         mfc_hash;
    struct list_head        mfc_cache_list;
    int maxvif;
    u32 cache_resolve_queue_len;
    bool mroute_do_assert;
    bool mroute_do_pim;
    bool mroute_do_wrvifwhole;
    int mroute_reg_vif_num;
 };

(that last brace is indented in the source and honestly? it's got main character energy, we don't touch it 🤭)

🎀 Members 🎀

okay so here's the whole roster, one by one, no skips, we don't do that here 🫶

• work — used for table destruction 💀 (yes it literally does the goodbye shift)
• list — entry within a list of multicast routing tables — it's on the list, literally
• net — the net where this table belongs 🌐
• ops — protocol specific operations
• id — identifier of the table
• mroute_sk — socket associated with the table
• ipmr_expire_timer — timer for handling unresolved routes ⏰
• mfc_unres_queue — list of unresolved MFC entries
• vif_table — array containing all possible vifs (yes, all of them, MAXVIFS of them 👑)
• mfc_hash — Hash table of all resolved routes for easy lookup 🔍
• mfc_cache_list — list of resolved routes for possible traversal (the source page spells it "resovled" and honestly same, spelling is hard, the routes are resolved though fr fr)
• maxvif — Identifier of highest value vif currently in use
• cache_resolve_queue_len — current size of unresolved queue
• mroute_do_assert — Whether to inform userspace on wrong ingress 👀
• mroute_do_pim — Whether to receive IGMP PIMv1
• mroute_reg_vif_num — PIM-device vif index

heads up bestie: the struct up there also declares mroute_do_wrvifwhole, and the Members list just... doesn't explain it. it's in the struct, it's iconically undocumented, that's the vibe check. 🙈

🦋 SEE ALSO 🦋

go read these next, i'm obsessed with them for you:

• Kernel file ./include/linux/mroute_base.h
• struct vif_device(9)
• struct mr_mfc(9)
• struct mr_table_ops(9)

and that's the whole page, no cap ✨ this one comes straight out of ./include/linux and it's dated October 2026 — so like, future-dated, time-traveling kernel lore, slay 💅🎀