From 22a7b477b34f868d9fb26f29e93f0c19d80405b7 Mon Sep 17 00:00:00 2001
From: Brian Downs <brian.downs@gmail.com>
Date: Wed, 9 Mar 2022 14:25:59 -0700
Subject: [PATCH] add net util funcs (#5245)

---
 pkg/util/net.go | 115 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)

diff --git a/pkg/util/net.go b/pkg/util/net.go
index 62e14cd9b8..804a33b917 100644
--- a/pkg/util/net.go
+++ b/pkg/util/net.go
@@ -80,6 +80,46 @@ func JoinIP4Nets(elems []*net.IPNet) string {
 	return strings.Join(strs, ",")
 }
 
+// GetFirst6 returns the first IPv6 address from the list of IP addresses.
+// If no IPv6 addresses are found, an error is raised.
+func GetFirst6(elems []net.IP) (net.IP, error) {
+	for _, elem := range elems {
+		if elem == nil || elem.To16() == nil {
+			continue
+		}
+		return elem, nil
+	}
+	return nil, errors.New("no IPv6 address found")
+}
+
+// GetFirst6Net returns the first IPv4 network from the list of IP networks.
+// If no IPv6 addresses are found, an error is raised.
+func GetFirst6Net(elems []*net.IPNet) (*net.IPNet, error) {
+	for _, elem := range elems {
+		if elem == nil || elem.IP.To16() == nil {
+			continue
+		}
+		return elem, nil
+	}
+	return nil, errors.New("no IPv6 CIDRs found")
+}
+
+// GetFirst6String returns the first IPv6 address from a list of IP address strings.
+// If no IPv6 addresses are found, an error is raised.
+func GetFirst6String(elems []string) (string, error) {
+	ips := []net.IP{}
+	for _, elem := range elems {
+		for _, v := range strings.Split(elem, ",") {
+			ips = append(ips, net.ParseIP(v))
+		}
+	}
+	ip, err := GetFirst6(ips)
+	if err != nil {
+		return "", err
+	}
+	return ip.String(), nil
+}
+
 // JoinIP6Nets stringifies and joins a list of IPv6 networks with commas.
 func JoinIP6Nets(elems []*net.IPNet) string {
 	var strs []string
@@ -141,3 +181,78 @@ func ParseStringSliceToIPs(s cli.StringSlice) ([]net.IP, error) {
 
 	return ips, nil
 }
+
+// GetFirstIP returns the first IPv4 address from the list of IP addresses.
+// If no IPv4 addresses are found, returns the first IPv6 address
+// if neither of IPv4 or IPv6 are found an error is raised.
+// Additionally matching listen address and IP version is returned.
+func GetFirstIP(nodeIPs []net.IP) (net.IP, string, bool, error) {
+	nodeIP, err := GetFirst4(nodeIPs)
+	ListenAddress := "0.0.0.0"
+	IPv6only := false
+	if err != nil {
+		nodeIP, err = GetFirst6(nodeIPs)
+		if err != nil {
+			return nil, "", false, err
+		}
+		ListenAddress = "::"
+		IPv6only = true
+	}
+	return nodeIP, ListenAddress, IPv6only, nil
+}
+
+// GetFirstNet returns the first IPv4 network from the list of IP networks.
+// If no IPv4 addresses are found, returns the first IPv6 address
+// if neither of IPv4 or IPv6 are found an error is raised.
+func GetFirstNet(elems []*net.IPNet) (*net.IPNet, error) {
+	serviceIPRange, err := GetFirst4Net(elems)
+	if err != nil {
+		serviceIPRange, err = GetFirst6Net(elems)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return serviceIPRange, nil
+}
+
+// GetFirstString returns the first IP4 address from a list of IP address strings.
+// If no IPv4 addresses are found, returns the first IPv6 address
+// if neither of IPv4 or IPv6 are found an error is raised.
+func GetFirstString(elems []string) (string, bool, error) {
+	ip, err := GetFirst4String(elems)
+	IPv6only := false
+	if err != nil {
+		ip, err = GetFirst6String(elems)
+		if err != nil {
+			return "", false, err
+		}
+		IPv6only = true
+	}
+	return ip, IPv6only, nil
+}
+
+// IsIPv6OnlyCIDRs returns if
+// - all are valid cidrs
+// - at least one cidr from v6 family is found
+// - v4 family cidr is not found
+func IsIPv6OnlyCIDRs(cidrs []*net.IPNet) (bool, error) {
+	v4Found := false
+	v6Found := false
+	for _, cidr := range cidrs {
+		if cidr == nil {
+			return false, fmt.Errorf("cidr %v is invalid", cidr)
+		}
+
+		if v4Found && v6Found {
+			continue
+		}
+
+		if cidr.IP != nil && cidr.IP.To4() == nil {
+			v6Found = true
+			continue
+		}
+		v4Found = true
+	}
+
+	return !v4Found && v6Found, nil
+}