challenge.go

Documentation: github.com/letsencrypt/boulder/test/load-generator/acme

     1  package acme
     2  
     3  import (
     4  	"errors"
     5  	"fmt"
     6  	mrand "math/rand"
     7  	"strings"
     8  
     9  	"github.com/letsencrypt/boulder/core"
    10  )
    11  
    12  // ChallengeStrategy is an interface describing a strategy for picking
    13  // a challenge from a given authorization.
    14  type ChallengeStrategy interface {
    15  	PickChallenge(*core.Authorization) (*core.Challenge, error)
    16  }
    17  
    18  const (
    19  	// RandomChallengeStrategy is the name for a random challenge selection
    20  	// strategy that will choose one of the authorization's challenges at random.
    21  	RandomChallengeStrategy = "RANDOM"
    22  	// The following challenge strategies will always pick the named challenge
    23  	// type or return an error if there isn't a challenge of that type to pick.
    24  	HTTP01ChallengeStrategy    = "HTTP-01"
    25  	DNS01ChallengeStrategy     = "DNS-01"
    26  	TLSALPN01ChallengeStrategy = "TLS-ALPN-01"
    27  )
    28  
    29  // NewChallengeStrategy returns the ChallengeStrategy for the given
    30  // ChallengeStrategyName, or an error if it is unknown.
    31  func NewChallengeStrategy(rawName string) (ChallengeStrategy, error) {
    32  	var preferredType core.AcmeChallenge
    33  	switch name := strings.ToUpper(rawName); name {
    34  	case RandomChallengeStrategy:
    35  		return &randomChallengeStrategy{}, nil
    36  	case HTTP01ChallengeStrategy:
    37  		preferredType = core.ChallengeTypeHTTP01
    38  	case DNS01ChallengeStrategy:
    39  		preferredType = core.ChallengeTypeDNS01
    40  	case TLSALPN01ChallengeStrategy:
    41  		preferredType = core.ChallengeTypeTLSALPN01
    42  	default:
    43  		return nil, fmt.Errorf("ChallengeStrategy %q unknown", name)
    44  	}
    45  
    46  	return &preferredTypeChallengeStrategy{
    47  		preferredType: preferredType,
    48  	}, nil
    49  }
    50  
    51  var (
    52  	ErrPickChallengeNilAuthz               = errors.New("PickChallenge: provided authorization can not be nil")
    53  	ErrPickChallengeAuthzMissingChallenges = errors.New("PickChallenge: provided authorization had no challenges")
    54  )
    55  
    56  // randomChallengeStrategy is a ChallengeStrategy implementation that always
    57  // returns a random challenge from the given authorization.
    58  type randomChallengeStrategy struct {
    59  }
    60  
    61  // PickChallenge for a randomChallengeStrategy returns a random challenge from
    62  // the authorization.
    63  func (strategy randomChallengeStrategy) PickChallenge(authz *core.Authorization) (*core.Challenge, error) {
    64  	if authz == nil {
    65  		return nil, ErrPickChallengeNilAuthz
    66  	}
    67  	if len(authz.Challenges) == 0 {
    68  		return nil, ErrPickChallengeAuthzMissingChallenges
    69  	}
    70  	return &authz.Challenges[mrand.Intn(len(authz.Challenges))], nil
    71  }
    72  
    73  // preferredTypeChallengeStrategy is a ChallengeStrategy implementation that
    74  // always returns the authorization's challenge with type matching the
    75  // preferredType.
    76  type preferredTypeChallengeStrategy struct {
    77  	preferredType core.AcmeChallenge
    78  }
    79  
    80  // PickChallenge for a preferredTypeChallengeStrategy returns the authorization
    81  // challenge that has Type equal the preferredType. An error is returned if the
    82  // challenge doesn't have an authorization matching the preferredType.
    83  func (strategy preferredTypeChallengeStrategy) PickChallenge(authz *core.Authorization) (*core.Challenge, error) {
    84  	if authz == nil {
    85  		return nil, ErrPickChallengeNilAuthz
    86  	}
    87  	if len(authz.Challenges) == 0 {
    88  		return nil, ErrPickChallengeAuthzMissingChallenges
    89  	}
    90  	for _, chall := range authz.Challenges {
    91  		if chall.Type == strategy.preferredType {
    92  			return &chall, nil
    93  		}
    94  	}
    95  	return nil, fmt.Errorf("authorization (ID %q) had no %q type challenge",
    96  		authz.ID,
    97  		strategy.preferredType)
    98  }
    99
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