-
Notifications
You must be signed in to change notification settings - Fork 320
/
misc.go
95 lines (81 loc) · 2.32 KB
/
misc.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
/*
* Copyright (C) 2020-2022, IrineSistiana
*
* This file is part of mosdns.
*
* mosdns is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* mosdns is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package misc_optm
import (
"context"
"github.com/IrineSistiana/mosdns/v4/coremain"
"github.com/IrineSistiana/mosdns/v4/pkg/dnsutils"
"github.com/IrineSistiana/mosdns/v4/pkg/executable_seq"
"github.com/IrineSistiana/mosdns/v4/pkg/query_context"
"github.com/miekg/dns"
"math/rand"
)
const (
PluginType = "misc_optm"
)
func init() {
coremain.RegNewPersetPluginFunc("_misc_optm", func(bp *coremain.BP) (coremain.Plugin, error) {
return &optm{BP: bp}, nil
})
}
var _ coremain.ExecutablePlugin = (*optm)(nil)
type optm struct {
*coremain.BP
}
func (t *optm) Exec(ctx context.Context, qCtx *query_context.Context, next executable_seq.ExecutableChainNode) error {
q := qCtx.Q()
// Block query that is unusual.
if len(q.Question) != 1 || q.Question[0].Qclass != dns.ClassINET {
r := new(dns.Msg)
r.SetRcode(q, dns.RcodeRefused)
qCtx.SetResponse(r, query_context.ContextStatusRejected)
return nil
}
if err := executable_seq.ExecChainNode(ctx, qCtx, next); err != nil {
return err
}
r := qCtx.R()
if r == nil {
return nil
}
// Trim and shuffle answers for A and AAAA.
switch qt := q.Question[0].Qtype; qt {
case dns.TypeA, dns.TypeAAAA:
rr := r.Answer[:0]
for _, ar := range r.Answer {
if ar.Header().Rrtype == qt {
rr = append(rr, ar)
}
ar.Header().Name = q.Question[0].Name
}
rand.Shuffle(len(rr), func(i, j int) {
rr[i], rr[j] = rr[j], rr[i]
})
r.Answer = rr
}
// Remove padding
if rOpt := r.IsEdns0(); rOpt != nil {
dnsutils.RemoveEDNS0Option(rOpt, dns.EDNS0PADDING)
}
// EDNS0 consistency
if qOpt := q.IsEdns0(); qOpt == nil {
dnsutils.RemoveEDNS0(r)
}
return nil
}