2019-10-01 12:22:30 -03:00

49 lines
1.3 KiB
Go

package banman
import (
"net"
)
var (
// defaultIPv4Mask is the default IPv4 mask used when parsing IP
// networks from an address. This ensures that the IP network only
// contains *one* IP address -- the one specified.
defaultIPv4Mask = net.CIDRMask(32, 32)
// defaultIPv6Mask is the default IPv6 mask used when parsing IP
// networks from an address. This ensures that the IP network only
// contains *one* IP address -- the one specified.
defaultIPv6Mask = net.CIDRMask(128, 128)
)
// ParseIPNet parses the IP network that contains the given address. An optional
// mask can be provided, to expand the scope of the IP network, otherwise the
// IP's default is used.
//
// NOTE: This assumes that the address has already been resolved.
func ParseIPNet(addr string, mask net.IPMask) (*net.IPNet, error) {
// If the address includes a port, we'll remove it.
host, _, err := net.SplitHostPort(addr)
if err != nil {
// Address doesn't include a port.
host = addr
}
// Parse the IP from the host to ensure it is supported.
ip := net.ParseIP(host)
switch {
case ip.To4() != nil:
if mask == nil {
mask = defaultIPv4Mask
}
case ip.To16() != nil:
if mask == nil {
mask = defaultIPv6Mask
}
default:
return nil, ErrUnsupportedIP
}
return &net.IPNet{IP: ip.Mask(mask), Mask: mask}, nil
}