[pve-devel] [RFC PATCH pve-installer v2 6/6] common: add checks for valid subnet mask and IPv4 address within subnet

[Christoph Heiss]

Apart from the one inline comment, looks good to me.

IMO it's not too restrictive, since IPv4 network/broadcast addresses
shouldn't really be used (and probably introduce subtle breakages)
outside of /31 prefixes anyway.

On Tue Apr 29, 2025 at 4:09 PM CEST, Michael Köppl wrote:
> Add checks for valid subnet mask (greater than /0 and at most /32 for
> IPv4). In addition, check if the address entered by the user is valid
> within the given subnet, i.e. not a network address or broadcast
> address. /31 is considered an exception in accordance with RFC3021 [0],
> considering any of the 2 available addresses to be valid host addresses.
>
> [0] https://datatracker.ietf.org/doc/html/rfc3021
>
> Signed-off-by: Michael Köppl <m.koeppl at proxmox.com>
> ---
> [..]
> diff --git a/proxmox-installer-common/src/utils.rs b/proxmox-installer-common/src/utils.rs
> index 1fe6a74..fea98db 100644
> --- a/proxmox-installer-common/src/utils.rs
> +++ b/proxmox-installer-common/src/utils.rs
> [..]
> @@ -133,6 +137,43 @@ fn mask_limit(addr: &IpAddr) -> usize {
>      if addr.is_ipv4() { 32 } else { 128 }
>  }
>
> +fn check_mask_limit(addr: &IpAddr, mask: usize) -> Result<(), CidrAddressParseError> {
> +    return if mask > mask_limit(&addr) {
> +        Err(CidrAddressParseError::InvalidMask(
> +            "mask cannot be greater than 32".into(),

s/32/mask_limit(&addr)/g

> +        ))
> +    } else {
> +        Ok(())
> +    };
> +}