IBV_QUERY_GID_EX(3)

💅 IBV_QUERY_GID_EX(3) — like, the Libibverbs Programmer's Manual one 🎀

okay bestie, so this is a page straight out of the Libibverbs Programmer's Manual and it's about peeking at a GID table entry. it's giving "small function, big energy" and honestly? we're obsessed. let's get into it ✨

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🌸 NAME 🌸

ibv_query_gid_ex — go query a GID table entry on an InfiniBand port, bestie. that's the whole vibe 🦋

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⭐ SYNOPSIS ⭐

#include <infiniband/verbs.h>

int ibv_query_gid_ex(struct ibv_context *context,
                     uint32_t port_num,
                     uint32_t gid_index,
                     struct ibv_gid_entry *entry,
                     uint32_t flags);

look at that signature. so clean. so iconic. 💅

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💖 DESCRIPTION 💖

so ibv_query_gid_ex() literally just returns the GID entry at entry for gid_index of port port_num for device context context. that's it. that's the function. no cap. 🫶

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🌈 ARGUMENTS 🌈

• context — the context of the device you're querying. your device's whole identity, basically main character energy 👑
• port_num — the number of the port whose GID table you wanna dig through 🔍
• gid_index — the index of the GID table entry you're asking about. like a little locker number, but for GIDs 🎀

🍓 the entry Argument 🍓

this one's an ibv_gid_entry struct, and it's defined right there in <infiniband/verbs.h> for you:

struct ibv_gid_entry {
    union ibv_gid gid;
    uint32_t gid_index;
    uint32_t port_num;
    uint32_t gid_type;
    uint32_t ndev_ifindex;
};

and here's what each field is serving ✨:

• gid — the GID entry itself. the moment. the star of the show ⭐
• gid_index — the GID table index of this entry 📇
• port_num — the port number that this GID belongs to 🚪
• gid_type — an enum ibv_gid_type, and it can be one of IBV_GID_TYPE_IB, IBV_GID_TYPE_ROCE_V1 or IBV_GID_TYPE_ROCE_V2. pick your fighter 💀
• ndev_ifindex — the interface index of the net device associated with this GID. it's 0 if there's no net device associated with it 🧚
• flags — extra fields to query post ndev_ifindex, and for now it must be 0. periodt. don't try to be cute with it 🙈

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🦋 RETURN VALUE 🦋

ibv_query_gid_ex() returns 0 on success, or an errno value on error. that's the whole deal, lowkey simple 💜

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💀 ERRORS 💀

• ENODATA — gid_index is within the GID table size of port port_num but there's literally no data in this index. the locker exists, it's just empty 😭

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🔥 SEE ALSO 🔥

ibv_open_device(3), ibv_query_device(3), ibv_query_pkey(3), ibv_query_port(3), ibv_query_gid_table(3)

go read those next, iykyk 📚✨

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👑 AUTHOR 👑

Parav Pandit <parav@nvidia.com> — thank you for this one, fr fr 🫶

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and that's the page!! this beauty is from libibverbs, dated 2020-04-24, and it ate, no crumbs. mwah 💋 🌸