Wednesday October 03, 2007

Kicking it Brussels-style

After 7 years of pretending to know something about I/O, I decided to see if I can pull the same trick with networking. The first project I chose to sabotage is Brussels. Project's mission can be described with a thousand words, but, the creative type that I am, I drew you a cool picture:

The first bit of code I've just contributed (here's the webrev) is mainly for the MAC services module. I added per-link property handles, which the network drivers can use like so:

    err = mac_prop_init("driver", instance, &handle);
    val = mac_prop_get_uint64(handle, "property");
    mac_prop_fini(handle);

For each plumbed link, MAC keeps a list of properties that ever entered the kernel. Pointers to these lists are stored in a hash table, using link name as a key. I also added MDB support for these data structures. The mac_proplist walker walks the hash table entries, and the mac_prop walker walks the property list, so you can say stuff like:

> ::walk mac_proplist | ::walk mac_prop | ::print mac_prop_t

Even more convenient is the new ::mac_prop dcmd (which internally uses the above walkers):

> ::help mac_prop

NAME
   mac_prop - display MAC properties of a link or all links

SYNOPSIS
   ::mac_prop [link]

ATTRIBUTES

   Target: kvm
   Module: mac
   Interface Stability: Unstable

 > ::mac_prop
            ADDR LINK             PROPERTY         SIZE VALUE
fffffffec7d80480 bge0             default_mtu      8    1500
fffffffec7d80a80 bge0             adv_autoneg_cap  1    1
 >

There wasn't an existing MDB module for MAC, so I created it too. Here's a good opportunity for other contributors to the MAC layer, hint hint, to add more MAC data structures to MDB.

(2007-10-03 16:40:52.0) Permalink