81 lines
1.5 KiB
Go
81 lines
1.5 KiB
Go
package main
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import (
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"math/rand"
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"net"
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"github.com/jedisct1/dlog"
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"github.com/miekg/dns"
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)
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type PluginECS struct {
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nets []*net.IPNet
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}
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func (plugin *PluginECS) Name() string {
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return "ecs"
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}
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func (plugin *PluginECS) Description() string {
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return "Set EDNS-client-subnet information in outgoing queries."
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}
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func (plugin *PluginECS) Init(proxy *Proxy) error {
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plugin.nets = proxy.ednsClientSubnets
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dlog.Notice("ECS plugin enabled")
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return nil
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}
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func (plugin *PluginECS) Drop() error {
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return nil
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}
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func (plugin *PluginECS) Reload() error {
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return nil
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}
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func (plugin *PluginECS) Eval(pluginsState *PluginsState, msg *dns.Msg) error {
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var options *[]dns.EDNS0
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for _, extra := range msg.Extra {
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if extra.Header().Rrtype == dns.TypeOPT {
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options = &extra.(*dns.OPT).Option
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for _, option := range *options {
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if option.Option() == dns.EDNS0SUBNET {
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return nil
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}
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}
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break
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}
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}
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if options == nil {
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msg.SetEdns0(uint16(pluginsState.maxPayloadSize), false)
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for _, extra := range msg.Extra {
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if extra.Header().Rrtype == dns.TypeOPT {
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options = &extra.(*dns.OPT).Option
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break
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}
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}
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}
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if options == nil {
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return nil
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}
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prr := dns.EDNS0_SUBNET{}
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prr.Code = dns.EDNS0SUBNET
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net := plugin.nets[rand.Intn(len(plugin.nets))]
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bits, totalSize := net.Mask.Size()
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if totalSize == 32 {
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prr.Family = 1
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} else if totalSize == 128 {
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prr.Family = 2
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} else {
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return nil
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}
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prr.SourceNetmask = uint8(bits)
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prr.SourceScope = 0
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prr.Address = net.IP
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*options = append(*options, &prr)
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return nil
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}
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