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Rewrite SRV targets and additional names in response (#4287)

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* Rewrite plugin - rewrite SRV targets and names in response answer and additional records

Signed-off-by: Nic Colledge <nic@njcolledge.net>

* Added README content to describe new behaviour

Signed-off-by: Nic Colledge <nic@njcolledge.net>

* Added more record types to rewrite handling based on PR/Issue feedback

Signed-off-by: Nic Colledge <nic@njcolledge.net>

* Updated README.md for plugin

Signed-off-by: Nic Colledge <nic@njcolledge.net>

* Updated unit tests.
Small refactor of getTarget... function.

Signed-off-by: Nic Colledge <nic@njcolledge.net>

* Refactor to add response value rewrite as answer value option

Signed-off-by: Nic Colledge <nic@njcolledge.net>

* Removed TODO comment, added test for NAPTR record.

Signed-off-by: Nic Colledge <nic@njcolledge.net>
This commit is contained in:
slick-nic
2021-02-23 09:12:40 +00:00
committed by GitHub
parent fe2b5f630d
commit 0103931263
10 changed files with 322 additions and 130 deletions
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104
plugin/rewrite/name.go
View File

@@ -37,10 +37,10 @@ type substringNameRule struct {
}
type regexNameRule struct {
NextAction string
Pattern *regexp.Regexp
Replacement string
ResponseRule
NextAction string
Pattern *regexp.Regexp
Replacement string
ResponseRules []ResponseRule
}
const (
@@ -113,7 +113,6 @@ func (rule *regexNameRule) Rewrite(ctx context.Context, state request.Request) R
// newNameRule creates a name matching rule based on exact, partial, or regex match
func newNameRule(nextAction string, args ...string) (Rule, error) {
var matchType, rewriteQuestionFrom, rewriteQuestionTo string
var rewriteAnswerField, rewriteAnswerFrom, rewriteAnswerTo string
if len(args) < 2 {
return nil, fmt.Errorf("too few arguments for a name rule")
}
@@ -140,8 +139,9 @@ func newNameRule(nextAction string, args ...string) (Rule, error) {
}
}
if len(args) > 3 && len(args) != 7 {
return nil, fmt.Errorf("response rewrites must consist only of a name rule with 3 arguments and an answer rule with 3 arguments")
//if len(args) > 3 && len(args) != 7 {
if len(args) > 3 && (len(args) - 3) % 4 != 0 {
return nil, fmt.Errorf("response rewrites must consist only of a name rule with 3 arguments and one or more answer rules with 3 arguments each")
}
if len(args) < 7 {
@@ -190,47 +190,39 @@ func newNameRule(nextAction string, args ...string) (Rule, error) {
nextAction,
rewriteQuestionFromPattern,
rewriteQuestionTo,
ResponseRule{
[]ResponseRule{{
Type: "name",
},
}},
}, nil
default:
return nil, fmt.Errorf("name rule supports only exact, prefix, suffix, substring, and regex name matching, received: %s", matchType)
}
}
if len(args) == 7 {
//if len(args) == 7 {
if (len(args) - 3) % 4 == 0 {
if matchType == RegexMatch {
if args[3] != "answer" {
return nil, fmt.Errorf("exceeded the number of arguments for a regex name rule")
}
rewriteQuestionFromPattern, err := isValidRegexPattern(rewriteQuestionFrom, rewriteQuestionTo)
if err != nil {
return nil, err
}
rewriteAnswerField = strings.ToLower(args[4])
switch rewriteAnswerField {
case "name":
default:
return nil, fmt.Errorf("exceeded the number of arguments for a regex name rule")
}
rewriteAnswerFrom = args[5]
rewriteAnswerTo = args[6]
rewriteAnswerFromPattern, err := isValidRegexPattern(rewriteAnswerFrom, rewriteAnswerTo)
if err != nil {
return nil, err
}
rewriteQuestionTo = plugin.Name(args[2]).Normalize()
rewriteAnswerTo = plugin.Name(args[6]).Normalize()
responseRuleCount := (len(args) - 3) / 4
responseRules := make([]ResponseRule, responseRuleCount)
for i := 0; i < responseRuleCount; i ++ {
startIdx := 3 + (i * 4)
responseRule, err := newResponseRule(args[startIdx:startIdx + 4])
if err != nil {
return nil, err
}
responseRules[i] = *responseRule
}
return &regexNameRule{
nextAction,
rewriteQuestionFromPattern,
rewriteQuestionTo,
ResponseRule{
Active: true,
Type: "name",
Pattern: rewriteAnswerFromPattern,
Replacement: rewriteAnswerTo,
},
responseRules,
}, nil
}
return nil, fmt.Errorf("the rewrite of response is supported only for name regex rule")
@@ -238,6 +230,34 @@ func newNameRule(nextAction string, args ...string) (Rule, error) {
return nil, fmt.Errorf("the rewrite rule is invalid: %s", args)
}
// newResponseRule creates a new "answer name" or "answer value" response rule.
func newResponseRule(args []string) (responseRule *ResponseRule, err error){
if args[0] != "answer" {
return nil, fmt.Errorf("exceeded the number of arguments for a regex name rule")
}
rewriteAnswerField := strings.ToLower(args[1])
switch rewriteAnswerField {
case "name":
case "value":
default:
return nil, fmt.Errorf("exceeded the number of arguments for a regex name rule")
}
rewriteAnswerFrom := args[2]
rewriteAnswerTo := args[3]
rewriteAnswerFromPattern, err := isValidRegexPattern(rewriteAnswerFrom, rewriteAnswerTo)
if err != nil {
return nil, err
}
rewriteAnswerTo = plugin.Name(args[3]).Normalize()
return &ResponseRule{
Active: true,
Type: rewriteAnswerField,
Pattern: rewriteAnswerFromPattern,
Replacement: rewriteAnswerTo,
}, nil
}
// Mode returns the processing nextAction
func (rule *exactNameRule) Mode() string { return rule.NextAction }
func (rule *prefixNameRule) Mode() string { return rule.NextAction }
@@ -245,20 +265,20 @@ func (rule *suffixNameRule) Mode() string { return rule.NextAction }
func (rule *substringNameRule) Mode() string { return rule.NextAction }
func (rule *regexNameRule) Mode() string { return rule.NextAction }
// GetResponseRule returns a rule to rewrite the response with. Currently not implemented.
func (rule *exactNameRule) GetResponseRule() ResponseRule { return rule.ResponseRule }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *exactNameRule) GetResponseRules() []ResponseRule { return []ResponseRule{rule.ResponseRule} }
// GetResponseRule returns a rule to rewrite the response with. Currently not implemented.
func (rule *prefixNameRule) GetResponseRule() ResponseRule { return ResponseRule{} }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *prefixNameRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
// GetResponseRule returns a rule to rewrite the response with. Currently not implemented.
func (rule *suffixNameRule) GetResponseRule() ResponseRule { return ResponseRule{} }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *suffixNameRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
// GetResponseRule returns a rule to rewrite the response with. Currently not implemented.
func (rule *substringNameRule) GetResponseRule() ResponseRule { return ResponseRule{} }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *substringNameRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
// GetResponseRule returns a rule to rewrite the response with.
func (rule *regexNameRule) GetResponseRule() ResponseRule { return rule.ResponseRule }
// GetResponseRules returns rules to rewrite the response with.
func (rule *regexNameRule) GetResponseRules() []ResponseRule { return rule.ResponseRules }
// hasClosingDot returns true if s has a closing dot at the end.
func hasClosingDot(s string) bool {