broadcast free arp when pod is setup

[changluyi]

• Make sure you have followed Kube-OVN Code Style.

What type of this PR

Examples of user facing changes:

• Features
• Bug fixes
• Docs
• Tests

Which issue(s) this PR fixes:

Fixes #(issue-number)

WHAT

🤖 Generated by Copilot at 4e8d30a

This pull request adds a new feature to enable or disable IP conflict detection in the kube-ovn controller, and improves the ARP handling for pod IP addresses. It introduces a new flag detectIPConflict and a new utility function BroadcastFreeArp in the util package, and modifies the configureNic and announce functions in the ovs_linux.go and ipam.go files respectively.

🤖 Generated by Copilot at 4e8d30a

BroadcastFreeArp
A new function for pods
To avoid conflict

HOW

🤖 Generated by Copilot at 4e8d30a

• Add a new utility function to broadcast free ARP requests (link)
• Use the new utility function to announce pod IP and MAC address after configuring the network interface (link)

[github-actions]

• The commit message is missing, it should provide a brief description of the changes made in this patch.
• There are no potential bugs or format errors in the code patch.
• The performance of the code patch seems fine.
• The code patch can be improved by adding comments to explain the purpose of each function and variable.

[github-actions]

• The commit message is missing, it should be added to provide context and explain the changes made in this patch.
• The code change seems to be correct, but there are some formatting issues that need to be fixed. Specifically, there are inconsistent uses of spaces around operators and commas. It would be better to follow a consistent style throughout the codebase.
• There are no potential bugs or performance issues in this code patch.
• The function BroadcastFreeArp could benefit from more descriptive variable names, especially for the parameters nic, ip, mac, announceNum, and announceInterval.
• In the BroadcastFreeArp function, there is an error message logged when parsing the IP address fails, but the function still returns nil instead of returning the error. It would be better to return the error so that the caller can handle it appropriately.

[oilbeater]

if err = ...; err != nil

[changluyi]

fixed

[oilbeater]

ifi should be replaced by more meaningful name

[changluyi]

replaced

[changluyi]

fixed

[github-actions]

• The commit message is missing, please add a descriptive message explaining the changes made in this patch.
• In the configureNic function, there is no need to check if addr.IP.To4() != nil before calling AnnounceArpAddress, as it is already being checked inside the function. This can be removed to simplify the code.
• In the AnnounceArpAddress function, the return value is always nil, nil. This should be changed to return only an error value, as it is not used anywhere in the code.
• In the AnnounceArpAddress function, the klog.Errorf call should be changed to klog.Warningf, as it is not a critical error and does not need to stop the execution of the program.
• In the AnnounceArpAddress function, the dstMac variable is never used and can be removed to simplify the code.

[github-actions]

• The commit message is missing. It should provide a brief description of the changes made in the patch.
• In the configureNic function, the newly added code block that broadcasts free ARP packets should be commented more clearly to explain its purpose and how it works.
• In the AnnounceArpAddress function, the error messages should be more specific to help with debugging. For example, instead of returning "failed to parse IP address", it could return "failed to parse IP address %s: %v" to include the actual IP address and the error message.
• In the AnnounceArpAddress function, the dstMac variable is hardcoded to broadcast to all MAC addresses. This might cause unnecessary network traffic and could be improved by broadcasting only to the target MAC address.
• In the AnnounceArpAddress function, the client.SetDeadline call might not be necessary since the timer already limits the duration of the write operation.