56 lines
1.2 KiB
Go
56 lines
1.2 KiB
Go
package dns
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import (
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"fmt"
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"net"
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)
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// EnsureIPv4 ensures that an ipv4 address is set for a domain name
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func EnsureIPv4(domainName string) (string, error) {
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ipv4, err := net.ResolveIPAddr("ip4", domainName)
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if err != nil {
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return "", err
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}
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// NOTE(d1): e.g. when there is only an ipv6 record available
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if ipv4 == nil {
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return "", fmt.Errorf("unable to resolve ipv4 address for %s", domainName)
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}
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return ipv4.String(), nil
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}
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// EnsureDomainsResolveSameIPv4 ensures that domains resolve to the same ipv4 address
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func EnsureDomainsResolveSameIPv4(domainName, server string) (string, error) {
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if server == "default" || server == "local" {
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return "", nil
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}
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var ipv4 string
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domainIPv4, err := EnsureIPv4(domainName)
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if err != nil {
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return ipv4, err
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}
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if domainIPv4 == "" {
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return ipv4, fmt.Errorf("cannot resolve ipv4 for %s?", domainName)
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}
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serverIPv4, err := EnsureIPv4(server)
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if err != nil {
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return ipv4, err
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}
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if serverIPv4 == "" {
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return ipv4, fmt.Errorf("cannot resolve ipv4 for %s?", server)
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}
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if domainIPv4 != serverIPv4 {
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err := "app domain %s (%s) does not appear to resolve to app server %s (%s)?"
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return ipv4, fmt.Errorf(err, domainName, domainIPv4, server, serverIPv4)
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}
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return ipv4, nil
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}
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