SUSE Labs Taipei Technology Sharing Day 2016

1. Use bonding driver with
ethernet
SUSE Labs Taipei technology sharing day
AL Cho
SUSE Labs Taipei
acho@suse.com

2. 2
Agenda
• 介紹 Bonding
• 基礎設置
‒ 使用 Yast
‒ 手動
• 講解範圍
‒ active-backup mode
• Code review
• 實際操作

3. Bonding

4. 4
介紹 Bonding / Introduce Bonding
• Bonding 是什麼？

5. 5
Networking Introduction
PC
/
Server
ip address
WWWroutereth0

6. 6
Networking Introduction
• Question:
‒ How to speed up ?
‒ How to do backup ?

7. 7
PC
Networking Introduction
How to speed up? How to do backup?
ip address 1
ip address 2
WWWrouter
eth0
eth1

8. 8
PC / Server
bond0
介紹 Bonding
bond0
eth1
eth0
router WWW
ip address

9. 9
介紹 Bonding
• Bonding 是什麼？
‒ Reference:
‒ NIC bonding (sometimes called NIC teaming) combines
multiple discreet physical NICs into a single logical
interface with all of the NICs sharing IP address, MAC
address, etc. This allows for redundant failover and can
sometimes provide improved transfer times for larger files
over a LAN.
‒ https://en.opensuse.org/SDB:Bonding

10. 10
Networking Introduction
• Question:
‒ How to speed up ?
‒ How to backup ?

11. 11
Networking Introduction
How to speed up?
ip address
WWWswitch
PC
/
Server
bond0
eth1
eth0

12. 12
Networking Introduction
How to do backup?
ip address
WWWswitch
PC
/
Server
bond0
eth0
eth1
X
(broken)
(enable for backup)

13. 13
介紹 Bonding
• Bonding 是什麼？
‒ Introduction

14. 14
介紹 Bonding
• Bonding 模式
‒ MODULE_PARM_DESC(mode,
"Mode of operation; 0 for balance-rr, "
"1 for active-backup, 2 for balance-xor, "
"3 for broadcast, 4 for 802.3ad, 5 for balance-tlb, "
"6 for balance-alb");

15. 15
介紹 Bonding
• Bonding 模式
‒ 0 for balance-rr (Round-robin)
‒ 1 for active-backup
‒ 2 for balance-xor
‒ 3 for broadcast
‒ 4 for 802.3ad (Dynamic link aggregation)
‒ 5 for balance-tlb (Adaptive transmit load balancing )
‒ 6 for balance-alb (Adaptive load balancing)

16. 16
基礎設置
How to configure it
• 設定 / Configuration
‒ 使用 Yast
‒ 手動 ( Documentation/networking/bonding.txt )

17. 實際操作 / Live Demo

18. Linux Kernel 重要機制

19. 19
重要機制
• *_ops
• register_netdevice_notifier / call_netdevice_notifier
• netlink
• rtnetlink_*

20. Code

21. 21
Code - module_init(bonding_init)
Drivers/net/bonding/bond_main.c
static int __init bonding_init(void)
{
int i;
int res;
pr_info("%s", bond_version);
res = bond_check_params(&bonding_defaults);
if (res)
goto out;
res = register_pernet_subsys(&bond_net_ops);
if (res)
goto out;

22. 22
Code - module_init(bonding_init)
res = bond_netlink_init();
if (res)
goto err_link;
bond_create_debugfs();
for (i = 0; i < max_bonds; i++) {
res = bond_create(&init_net, NULL);
if (res)
goto err;
}
register_netdevice_notifier(&bond_netdev_notifier);

23. 23
Code - module_init(bonding_init)
out:
return res;
err:
bond_destroy_debugfs();
bond_netlink_fini();
err_link:
unregister_pernet_subsys(&bond_net_ops);
goto out;
}

24. 24
Bonding.ko
module_init(bonding_init)
(bond_main.c)
(net/core/net_namespace.c)
int register_pernet_subsys(struct pernet_operations *ops)
register_pernet_subsys(&bond_net_ops)
Kernel

25. 25
Init module – point 1
• Use “register_pernet_subsys” - register a network
namespace subsystem
• What is network namespace?

26. 26
Bonding.ko
module_init(bonding_init)
(bond_main.c)
bond_netlink_init( )
(net/core/rtnetlink.c)
int rtnl_link_register(struct rtnl_link_ops *ops)
rtnl_link_register(&bond_link_ops)
Kernel

27. 27
Init module – point 2
• Use “ rtnl_link_register” - Register rtnl_link_ops with
rtnetlink
• What is rtnetlink ?

28. 28
Init module – point 3
• Use “bond_create”
• Create a new bond based on the specified name and bonding
parameters.
• If name is NULL, obtain a suitable "bond%d" name for us. Caller
must NOT hold rtnl_lock; we need to release it here before we
set up our sysfs entries.

29. 29
Bonding.ko
module_init(bonding_init)
(bond_main.c)
(net/core/dev.c)
int register_netdevice_notifier(struct notifier_block *nb)
register_netdevice_notifier(&bond_netdev_notifier)
Kernel

30. 30
Init module – point 4
• Use “register_netdevice_notifier” - register a network
notifier block
• Register a notifier to be called when network device
events occur.
• The notifier passed is linked into the kernel structures
and must not be reused until it has been unregistered.
A negative errno code is returned on a failure.
When registered all registration and up events are
replayed to the new notifier to allow device to have a
race free view of the network device list.

31. 31
Init module – point 4
• Use “register_netdevice_notifier” - register a network
notifier block
• What is network notifier block ?

32. 32
Init module – point 4
• Use “register_netdevice_notifier” - register a network
notifier block
• Why use raw_notifier_call_chain ?

33. 33
Init module – point 4
• Use “register_netdevice_notifier” - register a network
notifier block
• Why use raw_notifier_call_chain ?
commit f07d5b946510a54937a75a3654941e855ffdc4c2
Author: Alan Stern <stern@rowland.harvard.edu>
Date: Tue May 9 15:23:03 2006 -0700
[NET]: Make netdev_chain a raw notifier.
From: Alan Stern <stern@rowland.harvard.edu>
This chain does it's own locking via the RTNL semaphore, and
can also run recursively so adding a new mutex here was causing
deadlocks.

34. Thank you.
34
Question ?

35. 35
Reference
• http://nano-chicken.blogspot.com/2010/01/linux-modules8-no
• http://nano-chicken.blogspot.com/2011/02/linux-kernel81-noti
• https://www.kernel.org/doc/Documentation/networking/bondin
• http://linux.vbird.org/linux_enterprise/0110network.php#serve
• http://www.xuebuyuan.com/1788250.html

36. 36

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