Add IPv6 support to getifaddrs() on Windows

[izissise]

We now ask both IPv4 and IPv6 addresses to GetAdaptersAddresses

Ipv6 address flags fill up is left as a todo because I'm not sure how to get the same information as of Linux

I've tested on a x86_64 Windows machine and I get the same informations as of ipconfig.exe

[jart]

I'm asking copilot to take a deeper look. With IPv6 and IPv4 addresses, I would assume what you'd probably want to do is get the family of the socket, and filter results so that interfaces consistent with the socket's family are returned. This way you won't have an issue where code that only expects to iterate over ipv4 interfaces will get surprised. Is that how the BSDs do this?

Also review the brace movement at line 234-241. Name clash detection must work for IPv6.

[Copilot]

Pull request overview

This pull request adds IPv6 support to the getifaddrs() implementation on Windows by modifying the Windows-specific ioctl handling code. The implementation now queries both IPv4 and IPv6 addresses from GetAdaptersAddresses and stores IPv6-specific information in the host adapter information structure.

Changes:

• Modified GetAdaptersAddresses calls to use AF_UNSPEC instead of AF_INET to retrieve both IPv4 and IPv6 addresses
• Extended HostAdapterInfoNode structure with IPv6-specific fields (interface index, scope, prefix length, flags, and IPv6 address)
• Updated appendHostInfo to handle IPv6 addresses separately with scope detection logic
• Modified ioctl_siocgifconf_nt to populate IPv6 fields in the ifreq structure

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[izissise]

I'm asking copilot to take a deeper look. With IPv6 and IPv4 addresses, I would assume what you'd probably want to do is get the family of the socket, and filter results so that interfaces consistent with the socket's family are returned. This way you won't have an issue where code that only expects to iterate over ipv4 interfaces will get surprised. Is that how the BSDs do this?

The filtering would be done on the linked-list returned by getifaddrs, one should check that struct sockaddr *ifa_addr; is AF_INET if they want only ipv4 addresses

linux getifaddrs man says this

getifaddrs() first appeared in glibc 2.3, but before glibc 2.3.3, the implementation supported only IPv4 addresses; IPv6 support was added in glibc 2.3.3. Support of address
families other than IPv4 is available only on kernels that support netlink.

BSDs getifaddrs probably always returned ipv6

Also review the brace movement at line 234-241. Name clash detection must work for IPv6.

I think this is the intended behavior, contrary to ipv4, ipv6 ifaces can have multiples addresses on the same iface