added more uniform unique address checks

logic/ips/ips.go

@@ -0,0 +1,56 @@
+package ips
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/seancfoley/ipaddress-go/ipaddr"
+)
+
+// GetFirstAddr - gets the first valid address in a given IPv4 CIDR
+func GetFirstAddr(cidr4 string) (*ipaddr.IPAddress, error) {
+	currentCidr := ipaddr.NewIPAddressString(cidr4).GetAddress()
+	if !currentCidr.IsIPv4() {
+		return nil, fmt.Errorf("invalid IPv4 CIDR provided to GetFirstAddr")
+	}
+	lower := currentCidr.GetLower()
+	ipParts := strings.Split(lower.GetNetIPAddr().IP.String(), ".")
+	if ipParts[len(ipParts)-1] == "0" {
+		lower = lower.Increment(1)
+	}
+	return lower, nil
+}
+
+// GetLastAddr - gets the last valid address in a given IPv4 CIDR
+func GetLastAddr(cidr4 string) (*ipaddr.IPAddress, error) {
+	currentCidr := ipaddr.NewIPAddressString(cidr4).GetAddress()
+	if !currentCidr.IsIPv4() {
+		return nil, fmt.Errorf("invalid IPv4 CIDR provided to GetLastAddr")
+	}
+	upper := currentCidr.GetUpper()
+	ipParts := strings.Split(upper.GetNetIPAddr().IP.String(), ".")
+	if ipParts[len(ipParts)-1] == "255" {
+		upper = upper.Increment(-1)
+	}
+	return upper, nil
+}
+
+// GetFirstAddr6 - gets the first valid IPv6 address in a given IPv6 CIDR
+func GetFirstAddr6(cidr6 string) (*ipaddr.IPAddress, error) {
+	currentCidr := ipaddr.NewIPAddressString(cidr6).GetAddress()
+	if !currentCidr.IsIPv6() {
+		return nil, fmt.Errorf("invalid IPv6 CIDR provided to GetFirstAddr6")
+	}
+	lower := currentCidr.GetLower()
+	return lower, nil
+}
+
+// GetLastAddr6 - gets the last valid IPv6 address in a given IPv6 CIDR
+func GetLastAddr6(cidr6 string) (*ipaddr.IPAddress, error) {
+	currentCidr := ipaddr.NewIPAddressString(cidr6).GetAddress()
+	if !currentCidr.IsIPv6() {
+		return nil, fmt.Errorf("invalid IPv6 CIDR provided to GetLastAddr6")
+	}
+	lower := currentCidr.GetLower()
+	return lower, nil
+}