IP-SR(8)

📦
version 7.3.0 · 2 versions
, in alpine 3.23, alpine 3.24, arch rolling, centos-stream 10, centos-stream 9, fedora 44, nixos 26.05, nixpkgs unstable, ubuntu resolute, ubuntu stonking

IP-SR(8) 💖

okay bestie, gather round — this is the ip-sr page from section 8 of the Linux manual, and it's literally all about IPv6 Segment Routing management. No cap. 🦋

✨ NAME ✨

ip-sr — IPv6 Segment Routing management 👑

🌸 SYNOPSIS 🌸

ip sr  { COMMAND | help }

ip sr hmac show

ip sr hmac set KEYID ALGO

ip sr tunsrc show

ip sr tunsrc set ADDRESS

💅 DESCRIPTION 💅

So like, the ip sr command is your girl for configuring IPv6 Segment Routing (SRv6) internal parameters. Periodt. ✨

And which parameters, you ask? Two iconic ones:

  • the mapping between an HMAC key ID and its associated hashing algorithm and secret, and
  • the IPv6 address to use as source for encapsulated packets.

Now the tea on ip sr hmac set: it prompts you for a newline-terminated "passphrase", and that passphrase gets used as the HMAC secret for the corresponding key ID. And here's the thing, bestie — that "passphrase" is not stretched, it's used directly as the HMAC key. So it absolutely needs enough entropy to actually be a key, fr fr. 😭

A correct use would be, like, a passphrase you generated with:

head -c 32 /dev/random | base64 -w 0

A blank "passphrase" removes the mapping. bye bye mapping 🫶

The currently supported algorithms for ALGO are sha1 and sha256. that's it, that's the list 💜

And for the tunnel source: if it's set to the address :: (which is the default, lowkey), then an address of the egress interface will be selected. But — and this is important — since that operation may hinder performances, it is recommended to set a non-default address. slay responsibly. 💅

🎀 EXAMPLES 🎀

Configure an HMAC mapping for key ID 42 and hashing algorithm SHA-256

# ip sr hmac set 42 sha256

Set the tunnel source address to 2001:db8::1

# ip sr tunsrc set 2001:db8::1

🌈 SEE ALSO 🌈

💀 BUGS 💀

ip sr hmac set does not stretch the passphrase.

yes bestie, it's right there in the manual, I'm not making it up 🙈

🧚 AUTHOR 🧚

David Lebrun <david.lebrun@uclouvain.be> — icon, legend, the moment 👑

and that's the whole page, bestie!! this one shipped with iproute2, dated 14 Apr 2017. go configure some segment routing, you absolute main character 🦋💖✨

📦 where this page comes from