fix go linter issues

Signed-off-by: NikitaSkrynnik <nikita.skrynnik@xored.com>

pkg/tools/dualstackippool/ippool.go

@@ -20,22 +20,26 @@ package dualstackippool
 import (
 	"net"
 
-	"github.com/networkservicemesh/sdk/pkg/tools/ippool"
 	"github.com/pkg/errors"
+
+	"github.com/networkservicemesh/sdk/pkg/tools/ippool"
 )
 
+// DualStackIPPool holds available IPv4 and IPv6 addresses in the structure of red-black tree
 type DualStackIPPool struct {
 	IPv4IPPool *ippool.IPPool
 	IPv6IPPool *ippool.IPPool
 }
 
+// New instantiates a dualstack ip pool as red-black tree
 func New() *DualStackIPPool {
 	pool := new(DualStackIPPool)
 	pool.IPv4IPPool = ippool.New(net.IPv4len)
 	pool.IPv6IPPool = ippool.New(net.IPv6len)
 	return pool
 }
 
+// AddNetString - adds ip addresses from network to the pool by string value
 func (p *DualStackIPPool) AddNetString(ipNetString string) {
 	_, ipNet, err := net.ParseCIDR(ipNetString)
 	if err != nil {
@@ -44,6 +48,7 @@ func (p *DualStackIPPool) AddNetString(ipNetString string) {
 	p.AddNet(ipNet)
 }
 
+// AddNet - adds ip addresses from network to the pool
 func (p *DualStackIPPool) AddNet(ipNet *net.IPNet) {
 	if ipNet.IP.To4() != nil {
 		p.IPv4IPPool.AddNet(ipNet)
@@ -52,17 +57,20 @@ func (p *DualStackIPPool) AddNet(ipNet *net.IPNet) {
 	p.IPv6IPPool.AddNet(ipNet)
 }
 
+// ContainsString parses ip string and checks that pool contains ip
 func (p *DualStackIPPool) ContainsString(in string) bool {
 	return p.Contains(net.ParseIP(in))
 }
 
+// Contains checks that pool contains ip
 func (p *DualStackIPPool) Contains(ip net.IP) bool {
 	if ip.To4() != nil {
 		return p.IPv4IPPool.Contains(ip)
 	}
 	return p.IPv6IPPool.Contains(ip)
 }
 
+// PullIPString - returns requested IP address from the pool by string
 func (p *DualStackIPPool) PullIPString(in string) (*net.IPNet, error) {
 	ip, _, err := net.ParseCIDR(in)
 	if err != nil {
@@ -71,6 +79,7 @@ func (p *DualStackIPPool) PullIPString(in string) (*net.IPNet, error) {
 	return p.PullIP(ip)
 }
 
+// PullIP - returns requested IP address from the pool
 func (p *DualStackIPPool) PullIP(ip net.IP) (*net.IPNet, error) {
 	if ip.To4() != nil {
 		return p.IPv4IPPool.PullIP(ip)