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/*
** Copyright (C) 2001-2025 Zabbix SIA
**
** Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
** documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
** rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
** permit persons to whom the Software is furnished to do so, subject to the following conditions:
**
** The above copyright notice and this permission notice shall be included in all copies or substantial portions
** of the Software.
**
** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
** WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
** COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
** SOFTWARE.
**/
package zbxnet
import (
"fmt"
"net"
"regexp"
"strings"
)
// AllowedPeers is preparsed content of field Server
type AllowedPeers struct {
ips []net.IP
nets []*net.IPNet
names []string
}
// GetAllowedPeers is parses the Server field
func GetAllowedPeers(servers string) (allowedPeers *AllowedPeers, err error) {
const duplicateErrorMessage = "cannot parse the \"Server\" parameter: address \"%s\" specified more than once"
const regexDNSString = `^([a-zA-Z0-9_]{1}[a-zA-Z0-9_-]{0,62}){1}(\.[a-zA-Z0-9_]{1}[a-zA-Z0-9_-]{0,62})*[\._]?$`
ap := &AllowedPeers{}
if servers != "" {
opts := strings.Split(servers, ",")
for _, o := range opts {
peer := strings.Trim(o, " \t")
if _, peerNet, err := net.ParseCIDR(peer); nil == err {
if ap.isPresent(peerNet) {
return &AllowedPeers{}, fmt.Errorf(duplicateErrorMessage, peer)
}
ap.nets = append(ap.nets, peerNet)
maskLeadSize, maskTotalOnes := peerNet.Mask.Size()
if 0 == maskLeadSize && 128 == maskTotalOnes {
_, peerNet, _ = net.ParseCIDR("0.0.0.0/0")
if !ap.isPresent(peerNet) {
ap.nets = append(ap.nets, peerNet)
}
}
} else if peerip := net.ParseIP(peer); nil != peerip {
if ap.isPresent(peerip) {
return &AllowedPeers{}, fmt.Errorf(duplicateErrorMessage, peer)
}
ap.ips = append(ap.ips, peerip)
} else {
if ap.isPresent(peer) {
return &AllowedPeers{}, fmt.Errorf(duplicateErrorMessage, peer)
}
regexDNS := regexp.MustCompile(regexDNSString)
if !regexDNS.MatchString(peer) {
return &AllowedPeers{}, fmt.Errorf("invalid \"Server\" configuration: incorrect address"+
" parameter: \"%s\"", peer)
}
ap.names = append(ap.names, peer)
}
}
}
return ap, nil
}
// CheckPeer validate incoming connection peer
func (ap *AllowedPeers) CheckPeer(ip net.IP) bool {
if ap.checkNetIP(ip) {
return true
}
for _, nameAllowed := range ap.names {
if ips, err := net.LookupHost(nameAllowed); nil == err {
for _, ipPeer := range ips {
ipAllowed := net.ParseIP(ipPeer)
if ipAllowed.Equal(ip) {
return true
}
}
}
}
return false
}
func (ap *AllowedPeers) isPresent(value interface{}) bool {
switch v := value.(type) {
case *net.IPNet:
for _, va := range ap.nets {
maskLeadSize, _ := va.Mask.Size()
maskLeadSizeNew, _ := v.Mask.Size()
if maskLeadSize <= maskLeadSizeNew && va.Contains(v.IP) {
return true
}
}
case net.IP:
if ap.checkNetIP(v) {
return true
}
case string:
for _, v := range ap.names {
if v == value {
return true
}
}
}
return false
}
func (ap *AllowedPeers) checkNetIP(ip net.IP) bool {
for _, netAllowed := range ap.nets {
if netAllowed.Contains(ip) {
return true
}
}
for _, ipAllowed := range ap.ips {
if ipAllowed.Equal(ip) {
return true
}
}
return false
}
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