Add Support for Geneve (RFC8926)

[pouria]

Summary

if_geneve: Add geneve support (RFC8926)
geneve creates a generic network virtualization tunnel
interface for Tentant Systems over an L3 (IP/UDP) underlay network that
provides a Layer 2 (ethernet) or Layer 3 service using the geneve protocol.
This implementation is based on RFC8926.

• IPv4 and IPv6 is fully supported for both unicast and multicast underlay.
• Per-VNET geneve tunnel is implemented.
• RXCSUM/TXCSUM/TSO offloading capabilities are implemented.

Test Plan

see D55183

[zlei]

sys/net/if_geneve.c

1676

I'm recently fighting with ifp->if_drv_flags & IFF_DRV_RUNNING. I think the flag should ( if ever wanted ) be write only by the driver and protected by driver locks, but not by the net stack. For sync issue, the net stack should use atomic_load but not merely a test by ifp->if_drv_flags & IFF_DRV_RUNNING.

[glebius]

sys/net/if_geneve.c

1676

IMHO, the idea of the flag was not correct in the first place. A new properly written driver shall not rely on it as a measure to prevent the stack from talking to the driver.

[pouria]

Rebase and update according to 0bd0c3295ac09f759f2816b73cbd2d950e3bef7e .

• There is no ether_reassign, therefore, geneve_reassign removed for good.

All geneve tests are passed and reassignment is also tested.

[pouria]

Fix ability to modifying generic and link-specific attributes at the same time in geneve_clone_modify_nl

[pouria]

sbin/ifconfig/ifgeneve.c

233 ↗

(On Diff #168865)

D54443: @zlei
This is an example of netlink implementation of ifconfig for geneve.
For the same reason, we need the nl_parsed_geneve here.
That's why I want the nl_parsed_gre to be public KPI.

[pouria]

I'm going to breakdown this revision to be easier to review.
So, sorry for noise in advance.

[pouria]

Rebase geneve to main and limit this revision kernel only.
ifconfig netlink helper: D55174
ifconfig geneve implementation (netlink): D55184
ifconfig geneve implementation (without netlink): D55185
ifconfig(8) manual for geneve: D55181
geneve(4) manual: D55182
geneve tests: D55183
update geneve to follow RFC 6040: D55186

If you want to test all of the Geneve patches together,
you can find them with all patches applied on my github:
https://github.com/spmzt/freebsd-src/tree/geneve_total

[pouria]

@glebius Do you think removing nvlist/non-netlink support will help this revision get reviewed faster?
since it will reduce the code size.

[glebius]

Sorry if I wasn't clear - I have no objections against pushing this in. I'm not able to do a protocol level review, but wrt the interaction with the rest of the network stack all looks good to me.

P.S. My only comment was about use of IFF_DRV_RUNNING, which IMHO is not a real protection from stack calling into the driver. You can improve that later, though.

[pouria]

Rebase to main, apply and close D55186.

[pouria]

In D54172#1277853, @pouria wrote:

Do you think removing nvlist/non-netlink support will help this revision get reviewed faster?
since it will reduce the code size.

FYI, deleting nvlist/non-netlink support, removes ~550 LOC.

[zlei]

I have not looked through the related RFC. So this quick review is not completed.

sys/net/if.h

258–260

I'd like to test this HW offload feature for GENEVE, but I think the ethernet drivers in-tree are not ready for that yet. @pouria Do you have any WIP updates for any drivers ?

sys/net/if_geneve.c

98

The sx lock geneve_sx is only used in this file. Make it static to limit the scope.

613

I guess a memcmp() is sufficient ?

2103

The in-tree drivers are approaching to netlink based config. Shall we still support nvlist ?
@kp How do you think about this ?

3080

No need for parentheses in case labels.

3094

Ditto.

3107

I believe the default branch is unreachable.

3201

Shall the drivers be updated to support the inner csum offload ?

3237

Unreachable code.

The ip_output() shall handle the mbuf, and free it if error occurs. So this is not required.

3385

Ditto.

4534

Shall this move to VNET_SYSUNINIT ?

[pouria]

Address @zlei comments

[pouria]

Thank you for your review.

sys/net/if.h

258–260

You're right. There are drivers that should support GENEVE hw offload, but not implemented yet.
I want to work on it after geneve lands.
I'm currently busy with v6 and routing stack.

sys/net/if_geneve.c

613

It'll be used in line 785 to order entries on the ftable.
It's basically the same mechanism used in if_vxlan.

2103

np from me. I've a branch prepared without nvlist.
I also like to remove the nvlist support too.

3107

In that case, IMHO, we shouldn't panic.

3201

Of course, but I don't want to update them on this revision.
I prepared the CSUM requirements for geneve here and I'll update other drivers in another revision.

4534

It should, but please see the D54175.

[pouria]

kind ping @zlei

sys/net/if_geneve.c

2103

kind ping @kp

[kp]

sys/net/if_geneve.c

2103

I'm entirely on board with the "Netlink only" approach. I don't think it's a good idea to have multiple different sets of configuration code. Just do netlink, it's the best available option right now.

[zlei]

sys/net/if_geneve.c

4534

IMO the cloner is not to be blamed.

( The socket ) Leaking of refcount of prison should be handled properly on prison remove event. I have an idea to fix it, then destroy cloner via VNET_SYSUNINIT should work as intended.

[pouria]

Remove nvlist/ioctl support.

[pouria]

@kp @zlei Done.
Could you please review this again?
I just removed the support without netlink completely and successfully ran my tests.
There should be no nvlist interface/header left.
I also abandoned the support for ifconfig WITHOUT_NETLINK.

[pouria]

Final style check before landing.

[pouria]

Add spdx tag to geneve header and replace its email with my freebsd email.

[adrian]

sys/net/if_geneve.c

2869

why are there semicolons here? :p

[pouria]

@adrian done.

[pouria]

sys/net/if_geneve.c

2869

bad habit of declaring first and copying from it.
Nice catch!
How did you find that? :)))

[adrian]

sys/net/if_geneve.c

2869

eyeballs :p