mirror of
https://github.com/Control-D-Inc/ctrld.git
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b267572b38
This commit introduces split upstreams feature, allowing to configure what ip stack that ctrld will use to connect to upstream.
43 lines
1.1 KiB
Go
43 lines
1.1 KiB
Go
package ctrld
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import (
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"context"
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"crypto/tls"
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"net"
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"github.com/miekg/dns"
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)
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type dotResolver struct {
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uc *UpstreamConfig
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}
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func (r *dotResolver) Resolve(ctx context.Context, msg *dns.Msg) (*dns.Msg, error) {
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// The dialer is used to prevent bootstrapping cycle.
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// If r.endpoint is set to dns.controld.dev, we need to resolve
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// dns.controld.dev first. By using a dialer with custom resolver,
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// we ensure that we can always resolve the bootstrap domain
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// regardless of the machine DNS status.
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dialer := newDialer(net.JoinHostPort(bootstrapDNS, "53"))
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dnsTyp := uint16(0)
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if len(msg.Question) > 0 {
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dnsTyp = msg.Question[0].Qtype
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}
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tcpNet, _ := r.uc.netForDNSType(dnsTyp)
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dnsClient := &dns.Client{
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Net: tcpNet,
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Dialer: dialer,
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TLSConfig: &tls.Config{RootCAs: r.uc.certPool},
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}
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endpoint := r.uc.Endpoint
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if r.uc.BootstrapIP != "" {
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dnsClient.TLSConfig.ServerName = r.uc.Domain
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_, port, _ := net.SplitHostPort(endpoint)
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endpoint = net.JoinHostPort(r.uc.BootstrapIP, port)
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}
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answer, _, err := dnsClient.ExchangeContext(ctx, msg, endpoint)
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return answer, err
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}
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