58 lines
1.5 KiB
Go
58 lines
1.5 KiB
Go
package bdns
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import (
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"context"
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"fmt"
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"net"
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"github.com/miekg/dns"
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)
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// DNSError wraps a DNS error with various relevant information
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type DNSError struct {
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recordType uint16
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hostname string
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// Exactly one of rCode or underlying should be set.
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underlying error
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rCode int
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}
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func (d DNSError) Error() string {
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var detail string
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if d.underlying != nil {
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if netErr, ok := d.underlying.(*net.OpError); ok {
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if netErr.Timeout() {
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detail = detailDNSTimeout
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} else {
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detail = detailDNSNetFailure
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}
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// Note: we check d.underlying here even though `Timeout()` does this because the call to `netErr.Timeout()` above only
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// happens for `*net.OpError` underlying types!
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} else if d.underlying == context.Canceled || d.underlying == context.DeadlineExceeded {
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detail = detailDNSTimeout
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} else {
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detail = detailServerFailure
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}
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} else if d.rCode != dns.RcodeSuccess {
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detail = dns.RcodeToString[d.rCode]
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} else {
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detail = detailServerFailure
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}
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return fmt.Sprintf("DNS problem: %s looking up %s for %s", detail,
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dns.TypeToString[d.recordType], d.hostname)
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}
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// Timeout returns true if the underlying error was a timeout
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func (d DNSError) Timeout() bool {
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if netErr, ok := d.underlying.(*net.OpError); ok {
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return netErr.Timeout()
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} else if d.underlying == context.Canceled || d.underlying == context.DeadlineExceeded {
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return true
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}
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return false
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}
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const detailDNSTimeout = "query timed out"
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const detailDNSNetFailure = "networking error"
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const detailServerFailure = "server failure at resolver"
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