bdns

Documentation

Index

• func MockTimeoutError() *net.OpError
• func ProblemDetailsFromDNSError(err error) *probs.ProblemDetails
• type DNSResolver
• type DNSResolverImpl
  • func NewDNSResolverImpl(readTimeout time.Duration, servers []string, stats metrics.Scope, ...) *DNSResolverImpl
  • func NewTestDNSResolverImpl(readTimeout time.Duration, servers []string, stats metrics.Scope, ...) *DNSResolverImpl
  • func (dnsResolver *DNSResolverImpl) LookupCAA(ctx context.Context, hostname string) ([]*dns.CAA, error)
  • func (dnsResolver *DNSResolverImpl) LookupHost(ctx context.Context, hostname string) ([]net.IP, error)
  • func (dnsResolver *DNSResolverImpl) LookupMX(ctx context.Context, hostname string) ([]string, error)
  • func (dnsResolver *DNSResolverImpl) LookupTXT(ctx context.Context, hostname string) ([]string, []string, error)
• type MockDNSResolver
  • func (mock *MockDNSResolver) LookupCAA(_ context.Context, domain string) ([]*dns.CAA, error)
  • func (mock *MockDNSResolver) LookupHost(_ context.Context, hostname string) ([]net.IP, error)
  • func (mock *MockDNSResolver) LookupMX(_ context.Context, domain string) ([]string, error)
  • func (mock *MockDNSResolver) LookupTXT(_ context.Context, hostname string) ([]string, []string, error)

Functions

func MockTimeoutError

func MockTimeoutError() *net.OpError

MockTimeoutError returns a a net.OpError for which Timeout() returns true.

func ProblemDetailsFromDNSError

func ProblemDetailsFromDNSError(err error) *probs.ProblemDetails

ProblemDetailsFromDNSError checks the error returned from Lookup... methods and tests if the error was an underlying net.OpError or an error caused by resolver returning SERVFAIL or other invalid Rcodes and returns the relevant core.ProblemDetails. The detail string will contain a mention of the DNS record type and domain given.

Types

type DNSResolver

type DNSResolver interface {
	LookupTXT(context.Context, string) (txts []string, authorities []string, err error)
	LookupHost(context.Context, string) ([]net.IP, error)
	LookupCAA(context.Context, string) ([]*dns.CAA, error)
	LookupMX(context.Context, string) ([]string, error)
}

DNSResolver queries for DNS records

type DNSResolverImpl

type DNSResolverImpl struct {
	// contains filtered or unexported fields
}

DNSResolverImpl represents a client that talks to an external resolver

func NewDNSResolverImpl

func NewDNSResolverImpl(readTimeout time.Duration, servers []string, stats metrics.Scope, clk clock.Clock, maxTries int) *DNSResolverImpl

NewDNSResolverImpl constructs a new DNS resolver object that utilizes the provided list of DNS servers for resolution.

func NewTestDNSResolverImpl

func NewTestDNSResolverImpl(readTimeout time.Duration, servers []string, stats metrics.Scope, clk clock.Clock, maxTries int) *DNSResolverImpl

NewTestDNSResolverImpl constructs a new DNS resolver object that utilizes the provided list of DNS servers for resolution and will allow loopback addresses. This constructor should *only* be called from tests (unit or integration).

func (*DNSResolverImpl) LookupCAA

func (dnsResolver *DNSResolverImpl) LookupCAA(ctx context.Context, hostname string) ([]*dns.CAA, error)

LookupCAA sends a DNS query to find all CAA records associated with the provided hostname. If the response code from the resolver is SERVFAIL an empty slice of CAA records is returned.

func (*DNSResolverImpl) LookupHost

func (dnsResolver *DNSResolverImpl) LookupHost(ctx context.Context, hostname string) ([]net.IP, error)

LookupHost sends a DNS query to find all A records associated with the provided hostname. This method assumes that the external resolver will chase CNAME/DNAME aliases and return relevant A records. It will retry requests in the case of temporary network errors. It can return net package, context.Canceled, and context.DeadlineExceeded errors.

func (*DNSResolverImpl) LookupMX

func (dnsResolver *DNSResolverImpl) LookupMX(ctx context.Context, hostname string) ([]string, error)

LookupMX sends a DNS query to find a MX record associated hostname and returns the record target.

func (*DNSResolverImpl) LookupTXT

func (dnsResolver *DNSResolverImpl) LookupTXT(ctx context.Context, hostname string) ([]string, []string, error)

LookupTXT sends a DNS query to find all TXT records associated with the provided hostname which it returns along with the returned DNS authority section.

type MockDNSResolver

type MockDNSResolver struct {
}

MockDNSResolver is a mock

func (*MockDNSResolver) LookupCAA

func (mock *MockDNSResolver) LookupCAA(_ context.Context, domain string) ([]*dns.CAA, error)

LookupCAA returns mock records for use in tests.

func (*MockDNSResolver) LookupHost

func (mock *MockDNSResolver) LookupHost(_ context.Context, hostname string) ([]net.IP, error)

LookupHost is a mock

Note: see comments on LookupMX regarding email.only

func (*MockDNSResolver) LookupMX

func (mock *MockDNSResolver) LookupMX(_ context.Context, domain string) ([]string, error)

LookupMX is a mock

Note: the email.only domain must have an MX but no A or AAAA records. The mock LookupHost returns an address of 127.0.0.1 for all domains except for special cases, so MX-only domains must be handled in both LookupHost and LookupMX.

func (*MockDNSResolver) LookupTXT

func (mock *MockDNSResolver) LookupTXT(_ context.Context, hostname string) ([]string, []string, error)

LookupTXT is a mock