91 lines
2.1 KiB
Go
91 lines
2.1 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 transport
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import (
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"encoding/binary"
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"io"
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"github.com/IrineSistiana/mosdns/v5/pkg/pool"
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"github.com/miekg/dns"
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"go.uber.org/zap"
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"golang.org/x/exp/constraints"
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)
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const (
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dnsHeaderLen = 12 // minimum dns msg size
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)
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func copyMsgWithLenHdr(m []byte) (*[]byte, error) {
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l := len(m)
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if l > dns.MaxMsgSize {
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return nil, ErrPayloadOverFlow
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}
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bp := pool.GetBuf(l + 2)
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binary.BigEndian.PutUint16(*bp, uint16(l))
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copy((*bp)[2:], m)
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return bp, nil
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}
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func copyMsg(m []byte) *[]byte {
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bp := pool.GetBuf(len(m))
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copy((*bp), m)
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return bp
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}
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// readMsgUdp reads dns frame from r. r typically should be a udp connection.
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// It uses a 4kb rx buffer and ignores any payload that is too small for a dns msg.
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// If no error, the length of payload always >= 12 bytes.
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func readMsgUdp(r io.Reader) (*[]byte, error) {
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// TODO: Make this configurable?
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// 4kb should be enough.
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payload := pool.GetBuf(4095)
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readAgain:
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n, err := r.Read(*payload)
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if err != nil {
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pool.ReleaseBuf(payload)
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return nil, err
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}
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if n < dnsHeaderLen {
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goto readAgain
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}
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*payload = (*payload)[:n]
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return payload, err
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}
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func setDefaultGZ[T constraints.Float | constraints.Integer](i *T, s, d T) {
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if s > 0 {
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*i = s
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} else {
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*i = d
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}
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}
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var nopLogger = zap.NewNop()
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func setNonNilLogger(i **zap.Logger, s *zap.Logger) {
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if s != nil {
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*i = s
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} else {
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*i = nopLogger
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}
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}
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