rdma_cap_eth_ah(9)

📦 version 7.3.1, in nixpkgs unstable

💅 rdma_cap_eth_ah — like, the Kernel API Manual edition, bestie ✨

okay so picture this: you're deep in the kernel, you're poking at an ib_device, and you need to know ONE thing — is this port giving RoCE energy or not? That's the whole vibe of rdma_cap_eth_ah(9). Buckle up 🎀

🦋 NAME 🦋

rdma_cap_eth_ah — basically a vibe check that asks: does this device's port have the Ethernet Address Handle capability? 💖

✨ SYNOPSIS ✨

bool rdma_cap_eth_ah (const struct ib_device *device , u32 port_num );

like, that's it. that's the whole function. iconic behavior honestly 👑

🌸 ARGUMENTS 🌸

  • device — the device you're checking. the main character of this operation 🫶
  • port_num — the port number you're checking. yes, that one. the specific one 💅

💜 DESCRIPTION 💜

so. RoCE. it stands for InfiniBand over Ethernet, and ngl it's kind of a genius little trick — it uses a well defined technique to fabricate GIDs over Ethernet/IP specific addresses that are native to the port. like it's out here hand-crafting addresses, we love a resourceful queen 🧚

normally? packet headers are generated by the sending host adapter, no stress, automatic, slay. BUT — and this is the plot twist 😭 — when you're sending connectionless datagrams, we must manually inject the proper headers for the fabric we're communicating over. no autopilot, bestie. you're doing it by hand. 🔥

⭐ RETURN ⭐

returns true if we are running as a RoCE port and we must force the addition of a Global Route Header built from our Ethernet Address Handle into our header list for connectionless packets. so like, true = yes babe you're doing the manual header thing 💀

🌈 SEE ALSO 🌈

everything's connected, iykyk 💫 — kernel file ./include/rdma/ib_verbs.h, and:

no cap, that's a lot of friends. go read them too, they're all slaying in ./include/rdma 💀💖

okay that's the whole page bestie!! this little cutie lives in ./include/rdma, it's the October 2026 era, and it goes by rdma_cap_eth_ah(9) 🎀✨ go forth and check your Ethernet Address Handle capability, you absolute icon 👑🦋💜

📦 where this page comes from