67 lines
1.2 KiB
Go
67 lines
1.2 KiB
Go
package dns
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import (
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"context"
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"fmt"
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"net"
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"strings"
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"github.com/Dreamacro/clash/component/dialer"
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D "github.com/miekg/dns"
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)
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type client struct {
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*D.Client
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r *Resolver
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port string
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host string
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}
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func (c *client) Exchange(m *D.Msg) (msg *D.Msg, err error) {
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return c.ExchangeContext(context.Background(), m)
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}
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func (c *client) ExchangeContext(ctx context.Context, m *D.Msg) (msg *D.Msg, err error) {
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var ip net.IP
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if c.r == nil {
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// a default ip dns
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ip = net.ParseIP(c.host)
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} else {
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var err error
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if ip, err = c.r.ResolveIP(c.host); err != nil {
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println("?")
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return nil, fmt.Errorf("use default dns resolve failed: %w", err)
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}
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}
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d := dialer.Dialer()
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if dialer.DialHook != nil {
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network := "udp"
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if strings.HasPrefix(c.Client.Net, "tcp") {
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network = "tcp"
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}
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dialer.DialHook(d, network, ip)
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}
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c.Client.Dialer = d
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// miekg/dns ExchangeContext doesn't respond to context cancel.
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// this is a workaround
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type result struct {
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msg *D.Msg
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err error
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}
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ch := make(chan result, 1)
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go func() {
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msg, _, err := c.Client.Exchange(m, net.JoinHostPort(ip.String(), c.port))
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ch <- result{msg, err}
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}()
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select {
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case <-ctx.Done():
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return nil, ctx.Err()
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case ret := <-ch:
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return ret.msg, ret.err
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}
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}
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