bond procfs hw addr prints

bond procfs hw addr prints

[Jarod Wilson]

I've got a bug report for someone using a Intel OPA devices in a bond, 
and it appears these devices have a hardware address length of 20, 
opposed to the typical 6 on ethernet. When they dump 
/proc/net/bonding/bondX, it only prints the first 6 of the address, per 
%pM and mac_address_string(), while sysfs for the interface does print 
the right thing, since it uses sysfs_print_mac(), which takes a length 
argument.

So the question is... What's the best route to take here? Expand %pM to 
support variable length hardware addresses? Use sysfs_* in procfs? 
Reinvent the wheel? Nothing I've tinkered with just yet feels very 
clean, on top of not actually working yet. :)

-- 
Jarod Wilson
jarod@redhat.com

Re: bond procfs hw addr prints

[Jay Vosburgh]

Jarod Wilson <jarod@redhat.com> wrote:

>I've got a bug report for someone using a Intel OPA devices in a bond, and
>it appears these devices have a hardware address length of 20, opposed to
>the typical 6 on ethernet. When they dump /proc/net/bonding/bondX, it only
>prints the first 6 of the address, per %pM and mac_address_string(), while
>sysfs for the interface does print the right thing, since it uses
>sysfs_print_mac(), which takes a length argument.

	This (20 octet MAC length) is true for any Infiniband device.

>So the question is... What's the best route to take here? Expand %pM to
>support variable length hardware addresses? Use sysfs_* in procfs?
>Reinvent the wheel? Nothing I've tinkered with just yet feels very clean,
>on top of not actually working yet. :)

	sysfs_format_mac (not _print_mac) uses "%*phC", len, addr in its
format string.  Perhaps that format would be a better choice than %pM
for this case?

	-J

---
	-Jay Vosburgh, jay.vosburgh@canonical.com

Re: bond procfs hw addr prints

[Jarod Wilson]

On 2017-03-13 8:28 PM, Jay Vosburgh wrote:
> Jarod Wilson <jarod@redhat.com> wrote:
>
>> I've got a bug report for someone using a Intel OPA devices in a bond, and
>> it appears these devices have a hardware address length of 20, opposed to
>> the typical 6 on ethernet. When they dump /proc/net/bonding/bondX, it only
>> prints the first 6 of the address, per %pM and mac_address_string(), while
>> sysfs for the interface does print the right thing, since it uses
>> sysfs_print_mac(), which takes a length argument.
>
> 	This (20 octet MAC length) is true for any Infiniband device.
>
>> So the question is... What's the best route to take here? Expand %pM to
>> support variable length hardware addresses? Use sysfs_* in procfs?
>> Reinvent the wheel? Nothing I've tinkered with just yet feels very clean,
>> on top of not actually working yet. :)
>
> 	sysfs_format_mac (not _print_mac) uses "%*phC", len, addr in its
> format string.  Perhaps that format would be a better choice than %pM
> for this case?

Ah, I'd failed to fully grasp how %phC worked, had actually tried it w/o 
the * in there, and only the first char of the addr was printing. 
Working on an updated version that uses %*phC properly, which does look 
like the way to go here. (Didn't help that I was also looking at an 
older codebase that didn't have the sysfs_format_mac de-duplication). 
I'll try to have a tested patch in flight tomorrow.

-- 
Jarod Wilson
jarod@redhat.com

Re: bond procfs hw addr prints

[Jarod Wilson]

On 2017-03-13 10:06 PM, Jarod Wilson wrote:
> On 2017-03-13 8:28 PM, Jay Vosburgh wrote:
>> Jarod Wilson <jarod@redhat.com> wrote:
>>
>>> I've got a bug report for someone using a Intel OPA devices in a
>>> bond, and
>>> it appears these devices have a hardware address length of 20,
>>> opposed to
>>> the typical 6 on ethernet. When they dump /proc/net/bonding/bondX, it
>>> only
>>> prints the first 6 of the address, per %pM and mac_address_string(),
>>> while
>>> sysfs for the interface does print the right thing, since it uses
>>> sysfs_print_mac(), which takes a length argument.
>>
>>     This (20 octet MAC length) is true for any Infiniband device.
>>
>>> So the question is... What's the best route to take here? Expand %pM to
>>> support variable length hardware addresses? Use sysfs_* in procfs?
>>> Reinvent the wheel? Nothing I've tinkered with just yet feels very
>>> clean,
>>> on top of not actually working yet. :)
>>
>>     sysfs_format_mac (not _print_mac) uses "%*phC", len, addr in its
>> format string.  Perhaps that format would be a better choice than %pM
>> for this case?
>
> Ah, I'd failed to fully grasp how %phC worked, had actually tried it w/o
> the * in there, and only the first char of the addr was printing.
> Working on an updated version that uses %*phC properly, which does look
> like the way to go here. (Didn't help that I was also looking at an
> older codebase that didn't have the sysfs_format_mac de-duplication).
> I'll try to have a tested patch in flight tomorrow.

Hm... One problem I'm seeing: perm_hwaddr[ETH_ALEN], 
partner_system[ETH_ALEN], mac_addr_value[ETH_ALEN]. Looks like just 
about all places where storage for only ETH_ALEN is available needs to 
be adjusted to maybe MAX_ADDR_LEN?

So I have something tested that uses %*phC, but only on ethernet 
hardware so far, and I forsee bad juju for infiniband, because of that 
ETH_ALEN issue...

-- 
Jarod Wilson
jarod@redhat.com

Re: bond procfs hw addr prints

[Jarod Wilson]

On 2017-03-13 11:26 PM, Jarod Wilson wrote:
> On 2017-03-13 10:06 PM, Jarod Wilson wrote:
>> On 2017-03-13 8:28 PM, Jay Vosburgh wrote:
>>> Jarod Wilson <jarod@redhat.com> wrote:
>>>
>>>> I've got a bug report for someone using a Intel OPA devices in a
>>>> bond, and
>>>> it appears these devices have a hardware address length of 20,
>>>> opposed to
>>>> the typical 6 on ethernet. When they dump /proc/net/bonding/bondX, it
>>>> only
>>>> prints the first 6 of the address, per %pM and mac_address_string(),
>>>> while
>>>> sysfs for the interface does print the right thing, since it uses
>>>> sysfs_print_mac(), which takes a length argument.
>>>
>>>     This (20 octet MAC length) is true for any Infiniband device.
>>>
>>>> So the question is... What's the best route to take here? Expand %pM to
>>>> support variable length hardware addresses? Use sysfs_* in procfs?
>>>> Reinvent the wheel? Nothing I've tinkered with just yet feels very
>>>> clean,
>>>> on top of not actually working yet. :)
>>>
>>>     sysfs_format_mac (not _print_mac) uses "%*phC", len, addr in its
>>> format string.  Perhaps that format would be a better choice than %pM
>>> for this case?
>>
>> Ah, I'd failed to fully grasp how %phC worked, had actually tried it w/o
>> the * in there, and only the first char of the addr was printing.
>> Working on an updated version that uses %*phC properly, which does look
>> like the way to go here. (Didn't help that I was also looking at an
>> older codebase that didn't have the sysfs_format_mac de-duplication).
>> I'll try to have a tested patch in flight tomorrow.
>
> Hm... One problem I'm seeing: perm_hwaddr[ETH_ALEN],
> partner_system[ETH_ALEN], mac_addr_value[ETH_ALEN]. Looks like just
> about all places where storage for only ETH_ALEN is available needs to
> be adjusted to maybe MAX_ADDR_LEN?
>
> So I have something tested that uses %*phC, but only on ethernet
> hardware so far, and I forsee bad juju for infiniband, because of that
> ETH_ALEN issue...

After some possibly incomplete hacking, I've got an Infiniband bond now 
spewing:

$ cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: mlx4_ib0 (primary_reselect always)
Currently Active Slave: mlx4_ib0
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 100
Down Delay (ms): 100

Slave Interface: mlx4_ib0
MII Status: up
Speed: Unknown
Duplex: Unknown
Link Failure Count: 0
Permanent HW addr: 
80:00:02:08:fe:80:00:00:00:00:00:00:e4:1d:2d:03:00:1d:67:01
Slave queue ID: 0

I need to do a lot more testing with this set, but basically, I've 
replaced ETH_ALEN with MAX_ADDR_LEN anywhere I can, and added a function 
that takes addr_len as a param for address copies and put that in place 
of ether_addr_copy(), the used %*phC in bond_procfs.c to get the above.

-- 
Jarod Wilson
jarod@redhat.com