125 lines
3.0 KiB
Go
125 lines
3.0 KiB
Go
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"math/rand"
|
|
"net"
|
|
"strings"
|
|
|
|
"github.com/jedisct1/dlog"
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
type PluginForwardEntry struct {
|
|
domain string
|
|
servers []string
|
|
}
|
|
|
|
type PluginForward struct {
|
|
forwardMap []PluginForwardEntry
|
|
}
|
|
|
|
func (plugin *PluginForward) Name() string {
|
|
return "forward"
|
|
}
|
|
|
|
func (plugin *PluginForward) Description() string {
|
|
return "Route queries matching specific domains to a dedicated set of servers"
|
|
}
|
|
|
|
func (plugin *PluginForward) Init(proxy *Proxy) error {
|
|
dlog.Noticef("Loading the set of forwarding rules from [%s]", proxy.forwardFile)
|
|
lines, err := ReadTextFile(proxy.forwardFile)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
for lineNo, line := range strings.Split(lines, "\n") {
|
|
line = TrimAndStripInlineComments(line)
|
|
if len(line) == 0 {
|
|
continue
|
|
}
|
|
domain, serversStr, ok := StringTwoFields(line)
|
|
if !ok {
|
|
return fmt.Errorf(
|
|
"Syntax error for a forwarding rule at line %d. Expected syntax: example.com 9.9.9.9,8.8.8.8",
|
|
1+lineNo,
|
|
)
|
|
}
|
|
domain = strings.ToLower(domain)
|
|
var servers []string
|
|
for _, server := range strings.Split(serversStr, ",") {
|
|
server = strings.TrimSpace(server)
|
|
server = strings.TrimPrefix(server, "[")
|
|
server = strings.TrimSuffix(server, "]")
|
|
if ip := net.ParseIP(server); ip != nil {
|
|
if ip.To4() != nil {
|
|
server = fmt.Sprintf("%s:%d", server, 53)
|
|
} else {
|
|
server = fmt.Sprintf("[%s]:%d", server, 53)
|
|
}
|
|
}
|
|
dlog.Infof("Forwarding [%s] to %s", domain, server)
|
|
servers = append(servers, server)
|
|
}
|
|
if len(servers) == 0 {
|
|
continue
|
|
}
|
|
plugin.forwardMap = append(plugin.forwardMap, PluginForwardEntry{
|
|
domain: domain,
|
|
servers: servers,
|
|
})
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginForward) Drop() error {
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginForward) Reload() error {
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginForward) Eval(pluginsState *PluginsState, msg *dns.Msg) error {
|
|
qName := pluginsState.qName
|
|
qNameLen := len(qName)
|
|
var servers []string
|
|
for _, candidate := range plugin.forwardMap {
|
|
candidateLen := len(candidate.domain)
|
|
if candidateLen > qNameLen {
|
|
continue
|
|
}
|
|
if (qName[qNameLen-candidateLen:] == candidate.domain &&
|
|
(candidateLen == qNameLen || (qName[qNameLen-candidateLen-1] == '.'))) ||
|
|
(candidate.domain == ".") {
|
|
servers = candidate.servers
|
|
break
|
|
}
|
|
}
|
|
if len(servers) == 0 {
|
|
return nil
|
|
}
|
|
server := servers[rand.Intn(len(servers))]
|
|
pluginsState.serverName = server
|
|
client := dns.Client{Net: pluginsState.serverProto, Timeout: pluginsState.timeout}
|
|
respMsg, _, err := client.Exchange(msg, server)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if respMsg.Truncated {
|
|
client.Net = "tcp"
|
|
respMsg, _, err = client.Exchange(msg, server)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
if edns0 := respMsg.IsEdns0(); edns0 == nil || !edns0.Do() {
|
|
respMsg.AuthenticatedData = false
|
|
}
|
|
respMsg.Id = msg.Id
|
|
pluginsState.synthResponse = respMsg
|
|
pluginsState.action = PluginsActionSynth
|
|
pluginsState.returnCode = PluginsReturnCodeForward
|
|
return nil
|
|
}
|