124 lines
2.9 KiB
Go
124 lines
2.9 KiB
Go
/*
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* Copyright (C) 2020-2022, IrineSistiana
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*
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* This file is part of mosdns.
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*
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* mosdns is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* mosdns is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package black_hole
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import (
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"context"
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"fmt"
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"github.com/IrineSistiana/mosdns/v5/pkg/query_context"
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"github.com/IrineSistiana/mosdns/v5/plugin/executable/sequence"
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"github.com/miekg/dns"
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"net/netip"
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"strings"
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)
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const PluginType = "black_hole"
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func init() {
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sequence.MustRegExecQuickSetup(PluginType, QuickSetup)
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}
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var _ sequence.Executable = (*BlackHole)(nil)
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type BlackHole struct {
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ipv4 []netip.Addr
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ipv6 []netip.Addr
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}
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// QuickSetup format: [ipv4|ipv6] ...
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// Support both ipv4/a and ipv6/aaaa families.
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func QuickSetup(_ sequence.BQ, s string) (any, error) {
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return NewBlackHole(strings.Fields(s))
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}
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// NewBlackHole creates a new BlackHole with given ips.
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func NewBlackHole(ips []string) (*BlackHole, error) {
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b := &BlackHole{}
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for _, s := range ips {
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addr, err := netip.ParseAddr(s)
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if err != nil {
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return nil, fmt.Errorf("invalid ipv4 addr %s, %w", s, err)
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}
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if addr.Is4() {
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b.ipv4 = append(b.ipv4, addr)
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} else {
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b.ipv6 = append(b.ipv6, addr)
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}
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}
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return b, nil
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}
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// Exec implements sequence.Executable. It set a response with given ips if
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// query has corresponding qtypes.
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func (b *BlackHole) Exec(_ context.Context, qCtx *query_context.Context) error {
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if r := b.Response(qCtx.Q()); r != nil {
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qCtx.SetResponse(r)
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}
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return nil
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}
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// Response returns a response with given ips if query has corresponding qtypes.
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// Otherwise, it returns nil.
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func (b *BlackHole) Response(q *dns.Msg) *dns.Msg {
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if len(q.Question) != 1 {
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return nil
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}
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qName := q.Question[0].Name
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qtype := q.Question[0].Qtype
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switch {
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case qtype == dns.TypeA && len(b.ipv4) > 0:
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r := new(dns.Msg)
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r.SetReply(q)
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for _, addr := range b.ipv4 {
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rr := &dns.A{
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Hdr: dns.RR_Header{
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Name: qName,
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Rrtype: dns.TypeA,
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Class: dns.ClassINET,
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Ttl: 300,
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},
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A: addr.AsSlice(),
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}
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r.Answer = append(r.Answer, rr)
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}
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return r
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case qtype == dns.TypeAAAA && len(b.ipv6) > 0:
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r := new(dns.Msg)
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r.SetReply(q)
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for _, addr := range b.ipv6 {
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rr := &dns.AAAA{
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Hdr: dns.RR_Header{
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Name: qName,
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Rrtype: dns.TypeAAAA,
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Class: dns.ClassINET,
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Ttl: 300,
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},
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AAAA: addr.AsSlice(),
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}
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r.Answer = append(r.Answer, rr)
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}
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return r
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}
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return nil
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}
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