diff options
Diffstat (limited to 'vendor/github.com/apparentlymart/go-cidr/cidr/wrangling.go')
-rw-r--r-- | vendor/github.com/apparentlymart/go-cidr/cidr/wrangling.go | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/vendor/github.com/apparentlymart/go-cidr/cidr/wrangling.go b/vendor/github.com/apparentlymart/go-cidr/cidr/wrangling.go new file mode 100644 index 00000000..861a5f62 --- /dev/null +++ b/vendor/github.com/apparentlymart/go-cidr/cidr/wrangling.go @@ -0,0 +1,38 @@ +package cidr + +import ( + "fmt" + "math/big" + "net" +) + +func ipToInt(ip net.IP) (*big.Int, int) { + val := &big.Int{} + val.SetBytes([]byte(ip)) + if len(ip) == net.IPv4len { + return val, 32 + } else if len(ip) == net.IPv6len { + return val, 128 + } else { + panic(fmt.Errorf("Unsupported address length %d", len(ip))) + } +} + +func intToIP(ipInt *big.Int, bits int) net.IP { + ipBytes := ipInt.Bytes() + ret := make([]byte, bits/8) + // Pack our IP bytes into the end of the return array, + // since big.Int.Bytes() removes front zero padding. + for i := 1; i <= len(ipBytes); i++ { + ret[len(ret)-i] = ipBytes[len(ipBytes)-i] + } + return net.IP(ret) +} + +func insertNumIntoIP(ip net.IP, num int, prefixLen int) net.IP { + ipInt, totalBits := ipToInt(ip) + bigNum := big.NewInt(int64(num)) + bigNum.Lsh(bigNum, uint(totalBits-prefixLen)) + ipInt.Or(ipInt, bigNum) + return intToIP(ipInt, totalBits) +} |