110 lines
2.9 KiB
Go
110 lines
2.9 KiB
Go
/*
|
|
* 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 server
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"net"
|
|
|
|
"github.com/IrineSistiana/mosdns/v5/pkg/pool"
|
|
"github.com/miekg/dns"
|
|
"go.uber.org/zap"
|
|
)
|
|
|
|
type UDPServerOpts struct {
|
|
Logger *zap.Logger
|
|
}
|
|
|
|
// ServeUDP starts a server at c. It returns if c had a read error.
|
|
// It always returns a non-nil error.
|
|
// h is required. logger is optional.
|
|
func ServeUDP(c *net.UDPConn, h Handler, opts UDPServerOpts) error {
|
|
logger := opts.Logger
|
|
if logger == nil {
|
|
logger = nopLogger
|
|
}
|
|
|
|
listenerCtx, cancel := context.WithCancelCause(context.Background())
|
|
defer cancel(errListenerCtxCanceled)
|
|
|
|
rb := pool.GetBuf(dns.MaxMsgSize)
|
|
defer pool.ReleaseBuf(rb)
|
|
|
|
oobReader, oobWriter, err := initOobHandler(c)
|
|
if err != nil {
|
|
return fmt.Errorf("failed to init oob handler, %w", err)
|
|
}
|
|
var ob []byte
|
|
if oobReader != nil {
|
|
obp := pool.GetBuf(1024)
|
|
defer pool.ReleaseBuf(obp)
|
|
ob = *obp
|
|
}
|
|
|
|
for {
|
|
n, oobn, _, remoteAddr, err := c.ReadMsgUDPAddrPort(*rb, ob)
|
|
if err != nil {
|
|
if n == 0 {
|
|
// Err with zero read. Most likely because c was closed.
|
|
return fmt.Errorf("unexpected read err: %w", err)
|
|
}
|
|
// Temporary err.
|
|
logger.Warn("read err", zap.Error(err))
|
|
continue
|
|
}
|
|
|
|
q := new(dns.Msg)
|
|
if err := q.Unpack((*rb)[:n]); err != nil {
|
|
logger.Warn("invalid msg", zap.Error(err), zap.Binary("msg", (*rb)[:n]), zap.Stringer("from", remoteAddr))
|
|
continue
|
|
}
|
|
|
|
var dstIpFromCm net.IP
|
|
if oobReader != nil {
|
|
var err error
|
|
dstIpFromCm, err = oobReader(ob[:oobn])
|
|
if err != nil {
|
|
logger.Error("failed to get dst address from oob", zap.Error(err))
|
|
}
|
|
}
|
|
|
|
// handle query
|
|
go func() {
|
|
payload := h.Handle(listenerCtx, q, QueryMeta{ClientAddr: remoteAddr.Addr(), FromUDP: true}, pool.PackBuffer)
|
|
if payload == nil {
|
|
return
|
|
}
|
|
defer pool.ReleaseBuf(payload)
|
|
|
|
var oob []byte
|
|
if oobWriter != nil && dstIpFromCm != nil {
|
|
oob = oobWriter(dstIpFromCm)
|
|
}
|
|
if _, _, err := c.WriteMsgUDPAddrPort(*payload, oob, remoteAddr); err != nil {
|
|
logger.Warn("failed to write response", zap.Stringer("client", remoteAddr), zap.Error(err))
|
|
}
|
|
}()
|
|
}
|
|
}
|
|
|
|
type getSrcAddrFromOOB func(oob []byte) (net.IP, error)
|
|
type writeSrcAddrToOOB func(a net.IP) []byte
|