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plugin/rewrite: streamline the ResponseRule handling. (#4473)

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* plugin/rewrite: streamline the ResponseRule handling.

The functionality of a response rule is now completely encapsulated behind
a `ResponseRule` interface. This significantly simplifies the complete
processing flow, it enables more flexible response handling and it is possible
to eliminate lots of state flags, ifs and switches.

Based on the new flexibility the pull request also enables to support a
response name rewrite for all name rewrite types.
To be compatible, an explicit `answer auto` option is added to support
a best effort response rewrite (name and value).
Additionally now all name rewrite rules support additional name and value
reponse rewrite options.

Using this feature it is also possible now to rewrite a complete sub domain
hierarchy to a single domain name combined with a correct rewrite (#2389).

Signed-off-by: Uwe Krueger <uwe.krueger@sap.com>

* revert policy

Signed-off-by: Uwe Krueger <uwe.krueger@sap.com>

Co-authored-by: Miek Gieben <miek@miek.nl>
This commit is contained in:
Uwe Krueger
2021-05-04 10:05:45 +02:00
committed by GitHub
parent 696c8731d6
commit 40edf1e566
13 changed files with 889 additions and 521 deletions
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99
plugin/rewrite/README.md
View File

@@ -13,23 +13,36 @@ Rewrites are invisible to the client. There are simple rewrites (fast) and compl
A simplified/easy-to-digest syntax for *rewrite* is...
~~~
rewrite [continue|stop] FIELD [FROM TO|FROM TTL]
rewrite [continue|stop] FIELD [TYPE] [(FROM TO)|TTL] [OPTIONS]
~~~
* **FIELD** indicates what part of the request/response is being re-written.
* `type` - the type field of the request will be rewritten. FROM/TO must be a DNS record type (`A`, `MX`, etc.);
e.g., to rewrite ANY queries to HINFO, use `rewrite type ANY HINFO`.
* `class` - the class of the message will be rewritten. FROM/TO must be a DNS class type (`IN`, `CH`, or `HS`); e.g., to rewrite CH queries to IN use `rewrite class CH IN`.
* `name` - the query name in the _request_ is rewritten; by default this is a full match of the
name, e.g., `rewrite name example.net example.org`. Other match types are supported, see the **Name Field Rewrites** section below.
* `answer name` - the query name in the _response_ is rewritten. This option has special restrictions and requirements, in particular it must always combined with a `name` rewrite. See below in the **Response Rewrites** section.
* `edns0` - an EDNS0 option can be appended to the request as described below in the **EDNS0 Options** section.
* `class` - the class of the message will be rewritten. FROM/TO must be a DNS class type (`IN`, `CH`, or `HS`); e.g., to rewrite CH queries to IN use `rewrite class CH IN`.
* `edns0` - an EDNS0 option can be appended to the request as described below in the **EDNS0 Options** section.
* `ttl` - the TTL value in the _response_ is rewritten.
* **TYPE** this optional element can be specified for a `name` or `ttl` field.
If not given type `exact` will be assumed. If options should be specified the
type must be given.
* **FROM** is the name (exact, suffix, prefix, substring, or regex) or type to match
* **TO** is the destination name or type to rewrite to
* **TTL** is the number of seconds to set the TTL value to
* **TTL** is the number of seconds to set the TTL value to (only for field `ttl`)
* **OPTIONS**
for field `name` further options are possible controlling the response rewrites.
All name matching types support the following options
* `answer auto` - the names in the _response_ is rewritten in a best effort manner.
* `answer name FROM TO` - the query name in the _response_ is rewritten matching the from regex pattern.
* `answer value FROM TO` - the names in the _response_ is rewritten matching the from regex pattern.
See below in the **Response Rewrites** section for further details.
If you specify multiple rules and an incoming query matches multiple rules, the rewrite
will behave as follows:
@@ -49,7 +62,7 @@ client.
The syntax for name rewriting is as follows:
```
rewrite [continue|stop] name [exact|prefix|suffix|substring|regex] STRING STRING
rewrite [continue|stop] name [exact|prefix|suffix|substring|regex] STRING STRING [OPTIONS]
```
The match type, e.g., `exact`, `substring`, etc., triggers rewrite:
@@ -60,7 +73,8 @@ The match type, e.g., `exact`, `substring`, etc., triggers rewrite:
* **suffix**: when the name ends with the matching string
* **regex**: when the name in the question section of a request matches a regular expression
If the match type is omitted, the `exact` match type is assumed.
If the match type is omitted, the `exact` match type is assumed. If OPTIONS are
given, the type must be specified.
The following instruction allows rewriting names in the query that
contain the substring `service.us-west-1.example.org`:
@@ -95,7 +109,8 @@ rewrite name suffix .schmoogle.com. .google.com.
### Response Rewrites
When rewriting incoming DNS requests' names, CoreDNS re-writes the `QUESTION SECTION`
When rewriting incoming DNS requests' names (field `name`), CoreDNS re-writes
the `QUESTION SECTION`
section of the requests. It may be necessary to rewrite the `ANSWER SECTION` of the
requests, because some DNS resolvers treat mismatches between the `QUESTION SECTION`
and `ANSWER SECTION` as a man-in-the-middle attack (MITM).
@@ -127,6 +142,35 @@ ftp.service.us-west-1.consul. 0 IN A 10.30.30.30
The above is a mismatch between the question asked and the answer provided.
There are three possibilities to specify an answer rewrite:
- A rewrite can request a best effort answer rewrite by adding the option `answer auto`.
- A rewrite may specify a dedicated regex based response name rewrite with the
`answer name FROM TO` option.
- A regex based rewrite of record values like `CNAME`, `SRV`, etc, can be requested by
an `answer value FROM TO` option.
Hereby FROM/TO follow the rules for the `regex` name rewrite syntax.
#### Auto Response Name Rewrite
The following configuration snippet allows for rewriting of the
`ANSWER SECTION` according to the rewrite of the `QUESTION SECTION`:
```
rewrite stop {
name suffix .coredns.rocks .service.consul answer auto
}
```
Any occurrence of the rewritten question in the answer is mapped
back to the original value before the rewrite.
Please note that answers for rewrites of type `exact` are always rewritten.
For a `suffix` name rule `auto` leads to a reverse suffix response rewrite,
exchanging FROM and TO from the rewrite request.
#### Explicit Response Name Rewrite
The following configuration snippet allows for rewriting of the
`ANSWER SECTION`, provided that the `QUESTION SECTION` was rewritten:
@@ -151,9 +195,11 @@ ftp-us-west-1.coredns.rocks. 0 IN A 10.20.20.20
ftp-us-west-1.coredns.rocks. 0 IN A 10.30.30.30
```
#### Rewriting other Response Values
It is also possible to rewrite other values returned in the DNS response records
(e.g. the server names returned in `SRV` and `MX` records). This can be enabled by adding
the `answer value` to a name regex rule as specified below. `answer value` takes a
the `answer value FROM TO` option to a name rule as specified below. `answer value` takes a
regular expression and a rewrite name as parameters and works in the same way as the
`answer name` rule.
@@ -173,20 +219,29 @@ rewrite [continue|stop] {
```
Note that the above syntax is strict. For response rewrites, only `name`
rules are allowed to match the question section, and only by match type
`regex`. The answer rewrite must be after the name, as in the
syntax example.
rules are allowed to match the question section. The answer rewrite must be
after the name, as in the syntax example.
An alternate syntax for rewriting a DNS request and response is as
follows:
#### Multiple Response Rewrites
`name` and `value` rewrites can be chained by appending multiple answer rewrite
options. For all occurrences but the first one the keyword `answer` might be
omitted.
```options
answer (auto | (name|value FROM TO)) { [answer] (auto | (name|value FROM TO)) }
```
rewrite [continue|stop] name regex STRING STRING answer name STRING STRING [answer value STRING STRING]
For example:
```
rewrite [continue|stop] name regex FROM TO answer name FROM TO [answer] value FROM TO
```
When using `exact` name rewrite rules, the answer gets rewritten automatically,
and there is no need to define `answer name`. The rule below
rewrites the name in a request from `RED` to `BLUE`, and subsequently
and there is no need to define `answer name auto`. But it is still possible to define
additional `answer value` and `answer value` options.
The rule below rewrites the name in a request from `RED` to `BLUE`, and subsequently
rewrites the name in a corresponding response from `BLUE` to `RED`. The
client in the request would see only `RED` and no `BLUE`.
@@ -215,6 +270,7 @@ setting the TTL value really low.
The syntax for the TTL rewrite rule is as follows. The meaning of
`exact|prefix|suffix|substring|regex` is the same as with the name rewrite rules.
An omitted type is defaulted to `exact`.
```
rewrite [continue|stop] ttl [exact|prefix|suffix|substring|regex] STRING SECONDS
@@ -290,12 +346,3 @@ rewrite edns0 subnet set 24 56
* If the query's source IP address is an IPv4 address, the first 24 bits in the IP will be the network subnet.
* If the query's source IP address is an IPv6 address, the first 56 bits in the IP will be the network subnet.
## Full Syntax
The full plugin usage syntax is harder to digest...
~~~
rewrite [continue|stop] {type|class|edns0|name [exact|prefix|suffix|substring|regex [FROM TO answer name]]} FROM TO
~~~
The syntax above doesn't cover the multi-line block option for specifying a name request+response rewrite rule described in the **Response Rewrite** section.

9
plugin/rewrite/class.go
View File

@@ -30,18 +30,15 @@ func newClassRule(nextAction string, args ...string) (Rule, error) {
}
// Rewrite rewrites the current request.
func (rule *classRule) Rewrite(ctx context.Context, state request.Request) Result {
func (rule *classRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
if rule.fromClass > 0 && rule.toClass > 0 {
if state.Req.Question[0].Qclass == rule.fromClass {
state.Req.Question[0].Qclass = rule.toClass
return RewriteDone
return nil, RewriteDone
}
}
return RewriteIgnored
return nil, RewriteIgnored
}
// Mode returns the processing mode.
func (rule *classRule) Mode() string { return rule.NextAction }
// GetResponseRules return rules to rewrite the response with. Currently not implemented.
func (rule *classRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }

50
plugin/rewrite/edns0.go
View File

@@ -49,14 +49,14 @@ func setupEdns0Opt(r *dns.Msg) *dns.OPT {
}
// Rewrite will alter the request EDNS0 NSID option
func (rule *edns0NsidRule) Rewrite(ctx context.Context, state request.Request) Result {
func (rule *edns0NsidRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
o := setupEdns0Opt(state.Req)
for _, s := range o.Option {
if e, ok := s.(*dns.EDNS0_NSID); ok {
if rule.action == Replace || rule.action == Set {
e.Nsid = "" // make sure it is empty for request
return RewriteDone
return nil, RewriteDone
}
}
}
@@ -64,20 +64,17 @@ func (rule *edns0NsidRule) Rewrite(ctx context.Context, state request.Request) R
// add option if not found
if rule.action == Append || rule.action == Set {
o.Option = append(o.Option, &dns.EDNS0_NSID{Code: dns.EDNS0NSID, Nsid: ""})
return RewriteDone
return nil, RewriteDone
}
return RewriteIgnored
return nil, RewriteIgnored
}
// Mode returns the processing mode.
func (rule *edns0NsidRule) Mode() string { return rule.mode }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *edns0NsidRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
// Rewrite will alter the request EDNS0 local options.
func (rule *edns0LocalRule) Rewrite(ctx context.Context, state request.Request) Result {
func (rule *edns0LocalRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
o := setupEdns0Opt(state.Req)
for _, s := range o.Option {
@@ -85,7 +82,7 @@ func (rule *edns0LocalRule) Rewrite(ctx context.Context, state request.Request)
if rule.code == e.Code {
if rule.action == Replace || rule.action == Set {
e.Data = rule.data
return RewriteDone
return nil, RewriteDone
}
}
}
@@ -94,18 +91,15 @@ func (rule *edns0LocalRule) Rewrite(ctx context.Context, state request.Request)
// add option if not found
if rule.action == Append || rule.action == Set {
o.Option = append(o.Option, &dns.EDNS0_LOCAL{Code: rule.code, Data: rule.data})
return RewriteDone
return nil, RewriteDone
}
return RewriteIgnored
return nil, RewriteIgnored
}
// Mode returns the processing mode.
func (rule *edns0LocalRule) Mode() string { return rule.mode }
// GetResponseRules returns a rule to rewrite the response with. Currently not implemented.
func (rule *edns0LocalRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
// newEdns0Rule creates an EDNS0 rule of the appropriate type based on the args
func newEdns0Rule(mode string, args ...string) (Rule, error) {
if len(args) < 2 {
@@ -222,10 +216,10 @@ func (rule *edns0VariableRule) ruleData(ctx context.Context, state request.Reque
}
// Rewrite will alter the request EDNS0 local options with specified variables.
func (rule *edns0VariableRule) Rewrite(ctx context.Context, state request.Request) Result {
func (rule *edns0VariableRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
data, err := rule.ruleData(ctx, state)
if err != nil || data == nil {
return RewriteIgnored
return nil, RewriteIgnored
}
o := setupEdns0Opt(state.Req)
@@ -234,9 +228,9 @@ func (rule *edns0VariableRule) Rewrite(ctx context.Context, state request.Reques
if rule.code == e.Code {
if rule.action == Replace || rule.action == Set {
e.Data = data
return RewriteDone
return nil, RewriteDone
}
return RewriteIgnored
return nil, RewriteIgnored
}
}
}
@@ -244,18 +238,15 @@ func (rule *edns0VariableRule) Rewrite(ctx context.Context, state request.Reques
// add option if not found
if rule.action == Append || rule.action == Set {
o.Option = append(o.Option, &dns.EDNS0_LOCAL{Code: rule.code, Data: data})
return RewriteDone
return nil, RewriteDone
}
return RewriteIgnored
return nil, RewriteIgnored
}
// Mode returns the processing mode.
func (rule *edns0VariableRule) Mode() string { return rule.mode }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *edns0VariableRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
func isValidVariable(variable string) bool {
switch variable {
case
@@ -333,17 +324,17 @@ func (rule *edns0SubnetRule) fillEcsData(state request.Request, ecs *dns.EDNS0_S
}
// Rewrite will alter the request EDNS0 subnet option.
func (rule *edns0SubnetRule) Rewrite(ctx context.Context, state request.Request) Result {
func (rule *edns0SubnetRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
o := setupEdns0Opt(state.Req)
for _, s := range o.Option {
if e, ok := s.(*dns.EDNS0_SUBNET); ok {
if rule.action == Replace || rule.action == Set {
if rule.fillEcsData(state, e) == nil {
return RewriteDone
return nil, RewriteDone
}
}
return RewriteIgnored
return nil, RewriteIgnored
}
}
@@ -352,19 +343,16 @@ func (rule *edns0SubnetRule) Rewrite(ctx context.Context, state request.Request)
opt := &dns.EDNS0_SUBNET{Code: dns.EDNS0SUBNET}
if rule.fillEcsData(state, opt) == nil {
o.Option = append(o.Option, opt)
return RewriteDone
return nil, RewriteDone
}
}
return RewriteIgnored
return nil, RewriteIgnored
}
// Mode returns the processing mode
func (rule *edns0SubnetRule) Mode() string { return rule.mode }
// GetResponseRules return rules to rewrite the response with. Currently not implemented.
func (rule *edns0SubnetRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
// These are all defined actions.
const (
Replace = "replace"

514
plugin/rewrite/name.go
View File

@@ -9,38 +9,106 @@ import (
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
)
type exactNameRule struct {
NextAction string
From string
To string
ResponseRule
// stringRewriter rewrites a string
type stringRewriter interface {
rewriteString(src string) string
}
type prefixNameRule struct {
NextAction string
Prefix string
Replacement string
// regexStringRewriter can be used to rewrite strings by regex pattern.
// it contains all the information required to detect and execute a rewrite
// on a string.
type regexStringRewriter struct {
pattern *regexp.Regexp
replacement string
}
type suffixNameRule struct {
NextAction string
Suffix string
Replacement string
var _ stringRewriter = &regexStringRewriter{}
func newStringRewriter(pattern *regexp.Regexp, replacement string) stringRewriter {
return &regexStringRewriter{pattern, replacement}
}
type substringNameRule struct {
NextAction string
Substring string
Replacement string
func (r *regexStringRewriter) rewriteString(src string) string {
regexGroups := r.pattern.FindStringSubmatch(src)
if len(regexGroups) == 0 {
return src
}
s := r.replacement
for groupIndex, groupValue := range regexGroups {
groupIndexStr := "{" + strconv.Itoa(groupIndex) + "}"
s = strings.Replace(s, groupIndexStr, groupValue, -1)
}
return s
}
type regexNameRule struct {
NextAction string
Pattern *regexp.Regexp
Replacement string
ResponseRules []ResponseRule
// remapStringRewriter maps a dedicated string to another string
// it also maps a the domain of a sub domain.
type remapStringRewriter struct {
orig string
replacement string
}
var _ stringRewriter = &remapStringRewriter{}
func newRemapStringRewriter(orig, replacement string) stringRewriter {
return &remapStringRewriter{orig, replacement}
}
func (r *remapStringRewriter) rewriteString(src string) string {
if src == r.orig {
return r.replacement
}
if strings.HasSuffix(src, "."+r.orig) {
return src[0:len(src)-len(r.orig)] + r.replacement
}
return src
}
// suffixStringRewriter maps a dedicated suffix string to another string
type suffixStringRewriter struct {
suffix string
replacement string
}
var _ stringRewriter = &suffixStringRewriter{}
func newSuffixStringRewriter(orig, replacement string) stringRewriter {
return &suffixStringRewriter{orig, replacement}
}
func (r *suffixStringRewriter) rewriteString(src string) string {
if strings.HasSuffix(src, r.suffix) {
return strings.TrimSuffix(src, r.suffix) + r.replacement
}
return src
}
// nameRewriterResponseRule maps a record name according to a stringRewriter.
type nameRewriterResponseRule struct {
stringRewriter
}
func (r *nameRewriterResponseRule) RewriteResponse(rr dns.RR) {
rr.Header().Name = r.rewriteString(rr.Header().Name)
}
// valueRewriterResponseRule maps a record value according to a stringRewriter.
type valueRewriterResponseRule struct {
stringRewriter
}
func (r *valueRewriterResponseRule) RewriteResponse(rr dns.RR) {
value := getRecordValueForRewrite(rr)
if value != "" {
new := r.rewriteString(value)
if new != value {
setRewrittenRecordValue(rr, new)
}
}
}
const (
@@ -54,60 +122,173 @@ const (
SubstringMatch = "substring"
// RegexMatch matches when the name in the question section of a request matches a regular expression
RegexMatch = "regex"
// AnswerMatch matches an answer rewrite
AnswerMatch = "answer"
// AutoMatch matches the auto name answer rewrite
AutoMatch = "auto"
// NameMatch matches the name answer rewrite
NameMatch = "name"
// ValueMatch matches the value answer rewrite
ValueMatch = "value"
)
// Rewrite rewrites the current request based upon exact match of the name
type nameRuleBase struct {
nextAction string
auto bool
replacement string
static ResponseRules
}
func newNameRuleBase(nextAction string, auto bool, replacement string, staticResponses ResponseRules) nameRuleBase {
return nameRuleBase{
nextAction: nextAction,
auto: auto,
replacement: replacement,
static: staticResponses,
}
}
// responseRuleFor create for auto mode dynamically response rewriters for name and value
// reverting the mapping done by the name rewrite rule, which can be found in the state.
func (rule *nameRuleBase) responseRuleFor(state request.Request) (ResponseRules, Result) {
if !rule.auto {
return rule.static, RewriteDone
}
rewriter := newRemapStringRewriter(state.Req.Question[0].Name, state.Name())
rules := ResponseRules{
&nameRewriterResponseRule{rewriter},
&valueRewriterResponseRule{rewriter},
}
return append(rules, rule.static...), RewriteDone
}
// Mode returns the processing nextAction
func (rule *nameRuleBase) Mode() string { return rule.nextAction }
// exactNameRule rewrites the current request based upon exact match of the name
// in the question section of the request.
func (rule *exactNameRule) Rewrite(ctx context.Context, state request.Request) Result {
if rule.From == state.Name() {
state.Req.Question[0].Name = rule.To
return RewriteDone
}
return RewriteIgnored
type exactNameRule struct {
nameRuleBase
from string
}
// Rewrite rewrites the current request when the name begins with the matching string.
func (rule *prefixNameRule) Rewrite(ctx context.Context, state request.Request) Result {
if strings.HasPrefix(state.Name(), rule.Prefix) {
state.Req.Question[0].Name = rule.Replacement + strings.TrimPrefix(state.Name(), rule.Prefix)
return RewriteDone
func newExactNameRule(nextAction string, orig, replacement string, answers ResponseRules) Rule {
return &exactNameRule{
newNameRuleBase(nextAction, true, replacement, answers),
orig,
}
return RewriteIgnored
}
// Rewrite rewrites the current request when the name ends with the matching string.
func (rule *suffixNameRule) Rewrite(ctx context.Context, state request.Request) Result {
if strings.HasSuffix(state.Name(), rule.Suffix) {
state.Req.Question[0].Name = strings.TrimSuffix(state.Name(), rule.Suffix) + rule.Replacement
return RewriteDone
func (rule *exactNameRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
if rule.from == state.Name() {
state.Req.Question[0].Name = rule.replacement
return rule.responseRuleFor(state)
}
return RewriteIgnored
return nil, RewriteIgnored
}
// Rewrite rewrites the current request based upon partial match of the
// prefixNameRule rewrites the current request when the name begins with the matching string.
type prefixNameRule struct {
nameRuleBase
prefix string
}
func newPrefixNameRule(nextAction string, auto bool, prefix, replacement string, answers ResponseRules) Rule {
return &prefixNameRule{
newNameRuleBase(nextAction, auto, replacement, answers),
prefix,
}
}
func (rule *prefixNameRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
if strings.HasPrefix(state.Name(), rule.prefix) {
state.Req.Question[0].Name = rule.replacement + strings.TrimPrefix(state.Name(), rule.prefix)
return rule.responseRuleFor(state)
}
return nil, RewriteIgnored
}
// suffixNameRule rewrites the current request when the name ends with the matching string.
type suffixNameRule struct {
nameRuleBase
suffix string
}
func newSuffixNameRule(nextAction string, auto bool, suffix, replacement string, answers ResponseRules) Rule {
var rules ResponseRules
if auto {
// for a suffix rewriter better standard response rewrites can be done
// just by using the original suffix/replacement in the opposite order
rewriter := newSuffixStringRewriter(replacement, suffix)
rules = ResponseRules{
&nameRewriterResponseRule{rewriter},
&valueRewriterResponseRule{rewriter},
}
}
return &suffixNameRule{
newNameRuleBase(nextAction, false, replacement, append(rules, answers...)),
suffix,
}
}
func (rule *suffixNameRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
if strings.HasSuffix(state.Name(), rule.suffix) {
state.Req.Question[0].Name = strings.TrimSuffix(state.Name(), rule.suffix) + rule.replacement
return rule.responseRuleFor(state)
}
return nil, RewriteIgnored
}
// substringNameRule rewrites the current request based upon partial match of the
// name in the question section of the request.
func (rule *substringNameRule) Rewrite(ctx context.Context, state request.Request) Result {
if strings.Contains(state.Name(), rule.Substring) {
state.Req.Question[0].Name = strings.Replace(state.Name(), rule.Substring, rule.Replacement, -1)
return RewriteDone
}
return RewriteIgnored
type substringNameRule struct {
nameRuleBase
substring string
}
// Rewrite rewrites the current request when the name in the question
// section of the request matches a regular expression.
func (rule *regexNameRule) Rewrite(ctx context.Context, state request.Request) Result {
regexGroups := rule.Pattern.FindStringSubmatch(state.Name())
if len(regexGroups) == 0 {
return RewriteIgnored
func newSubstringNameRule(nextAction string, auto bool, substring, replacement string, answers ResponseRules) Rule {
return &substringNameRule{
newNameRuleBase(nextAction, auto, replacement, answers),
substring,
}
s := rule.Replacement
}
func (rule *substringNameRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
if strings.Contains(state.Name(), rule.substring) {
state.Req.Question[0].Name = strings.Replace(state.Name(), rule.substring, rule.replacement, -1)
return rule.responseRuleFor(state)
}
return nil, RewriteIgnored
}
// regexNameRule rewrites the current request when the name in the question
// section of the request matches a regular expression.
type regexNameRule struct {
nameRuleBase
pattern *regexp.Regexp
}
func newRegexNameRule(nextAction string, auto bool, pattern *regexp.Regexp, replacement string, answers ResponseRules) Rule {
return &regexNameRule{
newNameRuleBase(nextAction, auto, replacement, answers),
pattern,
}
}
func (rule *regexNameRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
regexGroups := rule.pattern.FindStringSubmatch(state.Name())
if len(regexGroups) == 0 {
return nil, RewriteIgnored
}
s := rule.replacement
for groupIndex, groupValue := range regexGroups {
groupIndexStr := "{" + strconv.Itoa(groupIndex) + "}"
s = strings.Replace(s, groupIndexStr, groupValue, -1)
}
state.Req.Question[0].Name = s
return RewriteDone
return rule.responseRuleFor(state)
}
// newNameRule creates a name matching rule based on exact, partial, or regex match
@@ -139,149 +320,106 @@ func newNameRule(nextAction string, args ...string) (Rule, error) {
}
}
//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 {
switch matchType {
case ExactMatch:
rewriteAnswerFromPattern, err := isValidRegexPattern(rewriteQuestionTo, rewriteQuestionFrom)
if err != nil {
return nil, err
}
return &exactNameRule{
nextAction,
rewriteQuestionFrom,
rewriteQuestionTo,
ResponseRule{
Active: true,
Type: "name",
Pattern: rewriteAnswerFromPattern,
Replacement: rewriteQuestionFrom,
},
}, nil
case PrefixMatch:
return &prefixNameRule{
nextAction,
rewriteQuestionFrom,
rewriteQuestionTo,
}, nil
case SuffixMatch:
return &suffixNameRule{
nextAction,
rewriteQuestionFrom,
rewriteQuestionTo,
}, nil
case SubstringMatch:
return &substringNameRule{
nextAction,
rewriteQuestionFrom,
rewriteQuestionTo,
}, nil
case RegexMatch:
rewriteQuestionFromPattern, err := isValidRegexPattern(rewriteQuestionFrom, rewriteQuestionTo)
if err != nil {
return nil, err
}
rewriteQuestionTo := plugin.Name(args[2]).Normalize()
return &regexNameRule{
nextAction,
rewriteQuestionFromPattern,
rewriteQuestionTo,
[]ResponseRule{{
Type: "name",
}},
}, nil
default:
return nil, fmt.Errorf("name rule supports only exact, prefix, suffix, substring, and regex name matching, received: %s", matchType)
var err error
var answers ResponseRules
auto := false
if len(args) > 3 {
auto, answers, err = parseAnswerRules(matchType, args[3:])
if err != nil {
return nil, err
}
}
//if len(args) == 7 {
if (len(args)-3)%4 == 0 {
if matchType == RegexMatch {
rewriteQuestionFromPattern, err := isValidRegexPattern(rewriteQuestionFrom, rewriteQuestionTo)
if err != nil {
return nil, err
}
rewriteQuestionTo = plugin.Name(args[2]).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,
responseRules,
}, nil
switch matchType {
case ExactMatch:
if _, err := isValidRegexPattern(rewriteQuestionTo, rewriteQuestionFrom); err != nil {
return nil, err
}
return nil, fmt.Errorf("the rewrite of response is supported only for name regex rule")
}
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":
return newExactNameRule(nextAction, rewriteQuestionFrom, rewriteQuestionTo, answers), nil
case PrefixMatch:
return newPrefixNameRule(nextAction, auto, rewriteQuestionFrom, rewriteQuestionTo, answers), nil
case SuffixMatch:
return newSuffixNameRule(nextAction, auto, rewriteQuestionFrom, rewriteQuestionTo, answers), nil
case SubstringMatch:
return newSubstringNameRule(nextAction, auto, rewriteQuestionFrom, rewriteQuestionTo, answers), nil
case RegexMatch:
rewriteQuestionFromPattern, err := isValidRegexPattern(rewriteQuestionFrom, rewriteQuestionTo)
if err != nil {
return nil, err
}
rewriteQuestionTo := plugin.Name(args[2]).Normalize()
return newRegexNameRule(nextAction, auto, rewriteQuestionFromPattern, rewriteQuestionTo, answers), nil
default:
return nil, fmt.Errorf("exceeded the number of arguments for a regex name rule")
return nil, fmt.Errorf("name rule supports only exact, prefix, suffix, substring, and regex name matching, received: %s", matchType)
}
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 }
func (rule *suffixNameRule) Mode() string { return rule.NextAction }
func (rule *substringNameRule) Mode() string { return rule.NextAction }
func (rule *regexNameRule) Mode() string { return rule.NextAction }
func parseAnswerRules(name string, args []string) (auto bool, rules ResponseRules, err error) {
auto = false
arg := 0
nameRules := 0
last := ""
if len(args) < 2 {
return false, nil, fmt.Errorf("invalid arguments for %s rule", name)
}
for arg < len(args) {
if last == "" && args[arg] != AnswerMatch {
if last == "" {
return false, nil, fmt.Errorf("exceeded the number of arguments for a non-answer rule argument for %s rule", name)
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *exactNameRule) GetResponseRules() []ResponseRule {
return []ResponseRule{rule.ResponseRule}
}
return false, nil, fmt.Errorf("exceeded the number of arguments for %s answer rule for %s rule", last, name)
}
if args[arg] == AnswerMatch {
arg++
}
if len(args)-arg == 0 {
return false, nil, fmt.Errorf("type missing for answer rule for %s rule", name)
}
last = args[arg]
arg++
switch last {
case AutoMatch:
auto = true
continue
case NameMatch:
if len(args)-arg < 2 {
return false, nil, fmt.Errorf("%s answer rule for %s rule: 2 arguments required", last, name)
}
rewriteAnswerFrom := args[arg]
rewriteAnswerTo := args[arg+1]
rewriteAnswerFromPattern, err := isValidRegexPattern(rewriteAnswerFrom, rewriteAnswerTo)
rewriteAnswerTo = plugin.Name(rewriteAnswerTo).Normalize()
if err != nil {
return false, nil, fmt.Errorf("%s answer rule for %s rule: %s", last, name, err)
}
rules = append(rules, &nameRewriterResponseRule{newStringRewriter(rewriteAnswerFromPattern, rewriteAnswerTo)})
arg += 2
nameRules++
case ValueMatch:
if len(args)-arg < 2 {
return false, nil, fmt.Errorf("%s answer rule for %s rule: 2 arguments required", last, name)
}
rewriteAnswerFrom := args[arg]
rewriteAnswerTo := args[arg+1]
rewriteAnswerFromPattern, err := isValidRegexPattern(rewriteAnswerFrom, rewriteAnswerTo)
rewriteAnswerTo = plugin.Name(rewriteAnswerTo).Normalize()
if err != nil {
return false, nil, fmt.Errorf("%s answer rule for %s rule: %s", last, name, err)
}
rules = append(rules, &valueRewriterResponseRule{newStringRewriter(rewriteAnswerFromPattern, rewriteAnswerTo)})
arg += 2
default:
return false, nil, fmt.Errorf("invalid type %q for answer rule for %s rule", last, name)
}
}
if auto && nameRules > 0 {
return false, nil, fmt.Errorf("auto name answer rule cannot be combined with explicit name anwer rules")
}
return
}
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *prefixNameRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *suffixNameRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *substringNameRule) GetResponseRules() []ResponseRule { return []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 {
return strings.HasSuffix(s, ".")

263
plugin/rewrite/name_test.go
View File

@@ -16,9 +16,9 @@ func TestRewriteIllegalName(t *testing.T) {
r, _ := newNameRule("stop", "example.org.", "example..org.")
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
noRevert: true,
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
RevertPolicy: NoRevertPolicy(),
}
ctx := context.TODO()
@@ -55,9 +55,9 @@ func TestRewriteNamePrefixSuffix(t *testing.T) {
}
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
noRevert: true,
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
RevertPolicy: NoRevertPolicy(),
}
m := new(dns.Msg)
@@ -75,6 +75,237 @@ func TestRewriteNamePrefixSuffix(t *testing.T) {
}
}
func TestRewriteNameNoRewrite(t *testing.T) {
ctx, close := context.WithCancel(context.TODO())
defer close()
tests := []struct {
next string
args []string
question string
expected string
}{
{"stop", []string{"prefix", "foo", "bar"}, "coredns.foo.", "coredns.foo."},
{"stop", []string{"prefix", "foo", "bar."}, "coredns.foo.", "coredns.foo."},
{"stop", []string{"suffix", "com", "org"}, "com.coredns.", "com.coredns."},
{"stop", []string{"suffix", "com", "org."}, "com.coredns.", "com.coredns."},
{"stop", []string{"substring", "service", "svc"}, "com.coredns.", "com.coredns."},
}
for i, tc := range tests {
r, err := newNameRule(tc.next, tc.args...)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
}
m := new(dns.Msg)
m.SetQuestion(tc.question, dns.TypeA)
rec := dnstest.NewRecorder(&test.ResponseWriter{})
_, err = rw.ServeDNS(ctx, rec, m)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
actual := rec.Msg.Answer[0].Header().Name
if actual != tc.expected {
t.Fatalf("Test %d: Expected answer rewrite to %v, got %v", i, tc.expected, actual)
}
}
}
func TestRewriteNamePrefixSuffixNoAutoAnswer(t *testing.T) {
ctx, close := context.WithCancel(context.TODO())
defer close()
tests := []struct {
next string
args []string
question string
expected string
}{
{"stop", []string{"prefix", "foo", "bar"}, "foo.example.com.", "bar.example.com."},
{"stop", []string{"prefix", "foo.", "bar."}, "foo.example.com.", "bar.example.com."},
{"stop", []string{"suffix", "com", "org"}, "foo.example.com.", "foo.example.org."},
{"stop", []string{"suffix", ".com", ".org"}, "foo.example.com.", "foo.example.org."},
{"stop", []string{"suffix", ".ingress.coredns.rocks", "nginx.coredns.rocks"}, "coredns.ingress.coredns.rocks.", "corednsnginx.coredns.rocks."},
}
for i, tc := range tests {
r, err := newNameRule(tc.next, tc.args...)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
}
m := new(dns.Msg)
m.SetQuestion(tc.question, dns.TypeA)
rec := dnstest.NewRecorder(&test.ResponseWriter{})
_, err = rw.ServeDNS(ctx, rec, m)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
actual := rec.Msg.Answer[0].Header().Name
if actual != tc.expected {
t.Fatalf("Test %d: Expected answer rewrite to %v, got %v", i, tc.expected, actual)
}
}
}
func TestRewriteNamePrefixSuffixAutoAnswer(t *testing.T) {
ctx, close := context.WithCancel(context.TODO())
defer close()
tests := []struct {
next string
args []string
question string
rewrite string
expected string
}{
{"stop", []string{"prefix", "foo", "bar", "answer", "auto"}, "foo.example.com.", "bar.example.com.", "foo.example.com."},
{"stop", []string{"prefix", "foo.", "bar.", "answer", "auto"}, "foo.example.com.", "bar.example.com.", "foo.example.com."},
{"stop", []string{"suffix", "com", "org", "answer", "auto"}, "foo.example.com.", "foo.example.org.", "foo.example.com."},
{"stop", []string{"suffix", ".com", ".org", "answer", "auto"}, "foo.example.com.", "foo.example.org.", "foo.example.com."},
{"stop", []string{"suffix", ".ingress.coredns.rocks", "nginx.coredns.rocks", "answer", "auto"}, "coredns.ingress.coredns.rocks.", "corednsnginx.coredns.rocks.", "coredns.ingress.coredns.rocks."},
}
for i, tc := range tests {
r, err := newNameRule(tc.next, tc.args...)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
RevertPolicy: NoRestorePolicy(),
}
m := new(dns.Msg)
m.SetQuestion(tc.question, dns.TypeA)
rec := dnstest.NewRecorder(&test.ResponseWriter{})
_, err = rw.ServeDNS(ctx, rec, m)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
rewrite := rec.Msg.Question[0].Name
if rewrite != tc.rewrite {
t.Fatalf("Test %d: Expected question rewrite to %v, got %v", i, tc.rewrite, rewrite)
}
actual := rec.Msg.Answer[0].Header().Name
if actual != tc.expected {
t.Fatalf("Test %d: Expected answer rewrite to %v, got %v", i, tc.expected, actual)
}
}
}
func TestRewriteNameExactAnswer(t *testing.T) {
ctx, close := context.WithCancel(context.TODO())
defer close()
tests := []struct {
next string
args []string
question string
rewrite string
expected string
}{
{"stop", []string{"exact", "coredns.rocks", "service.consul", "answer", "auto"}, "coredns.rocks.", "service.consul.", "coredns.rocks."},
{"stop", []string{"exact", "coredns.rocks.", "service.consul.", "answer", "auto"}, "coredns.rocks.", "service.consul.", "coredns.rocks."},
{"stop", []string{"exact", "coredns.rocks", "service.consul"}, "coredns.rocks.", "service.consul.", "coredns.rocks."},
{"stop", []string{"exact", "coredns.rocks.", "service.consul."}, "coredns.rocks.", "service.consul.", "coredns.rocks."},
{"stop", []string{"exact", "coredns.org.", "service.consul."}, "coredns.rocks.", "coredns.rocks.", "coredns.rocks."},
}
for i, tc := range tests {
r, err := newNameRule(tc.next, tc.args...)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
RevertPolicy: NoRestorePolicy(),
}
m := new(dns.Msg)
m.SetQuestion(tc.question, dns.TypeA)
rec := dnstest.NewRecorder(&test.ResponseWriter{})
_, err = rw.ServeDNS(ctx, rec, m)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
rewrite := rec.Msg.Question[0].Name
if rewrite != tc.rewrite {
t.Fatalf("Test %d: Expected question rewrite to %v, got %v", i, tc.rewrite, rewrite)
}
actual := rec.Msg.Answer[0].Header().Name
if actual != tc.expected {
t.Fatalf("Test %d: Expected answer rewrite to %v, got %v", i, tc.expected, actual)
}
}
}
func TestRewriteNameRegexAnswer(t *testing.T) {
ctx, close := context.WithCancel(context.TODO())
defer close()
tests := []struct {
next string
args []string
question string
rewrite string
expected string
}{
{"stop", []string{"regex", "(.*).coredns.rocks", "{1}.coredns.maps", "answer", "auto"}, "foo.coredns.rocks.", "foo.coredns.maps.", "foo.coredns.rocks."},
{"stop", []string{"regex", "(.*).coredns.rocks", "{1}.coredns.maps", "answer", "name", "(.*).coredns.maps", "{1}.coredns.works"}, "foo.coredns.rocks.", "foo.coredns.maps.", "foo.coredns.works."},
{"stop", []string{"regex", "(.*).coredns.rocks", "{1}.coredns.maps"}, "foo.coredns.rocks.", "foo.coredns.maps.", "foo.coredns.maps."},
}
for i, tc := range tests {
r, err := newNameRule(tc.next, tc.args...)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: []Rule{r},
RevertPolicy: NoRestorePolicy(),
}
m := new(dns.Msg)
m.SetQuestion(tc.question, dns.TypeA)
rec := dnstest.NewRecorder(&test.ResponseWriter{})
_, err = rw.ServeDNS(ctx, rec, m)
if err != nil {
t.Fatalf("Test %d: Expected no error, got %s", i, err)
}
rewrite := rec.Msg.Question[0].Name
if rewrite != tc.rewrite {
t.Fatalf("Test %d: Expected question rewrite to %v, got %v", i, tc.rewrite, rewrite)
}
actual := rec.Msg.Answer[0].Header().Name
if actual != tc.expected {
t.Fatalf("Test %d: Expected answer rewrite to %v, got %v", i, tc.expected, actual)
}
}
}
func TestNewNameRule(t *testing.T) {
tests := []struct {
next string
@@ -91,6 +322,26 @@ func TestNewNameRule(t *testing.T) {
{"stop", []string{"regex", "(.*).coredns.rocks", "{1}.coredns.rocks"}, false},
{"stop", []string{"regex", "(.*).coredns.rocks", "{1}.{2}.coredns.rocks"}, true},
{"stop", []string{"regex", "staging.mydomain.com", "aws-loadbalancer-id.us-east-1.elb.amazonaws.com"}, false},
{"stop", []string{"suffix", "staging.mydomain.com", "coredns.rock", "answer"}, true},
{"stop", []string{"suffix", "staging.mydomain.com", "coredns.rock", "answer", "name"}, true},
{"stop", []string{"suffix", "staging.mydomain.com", "coredns.rock", "answer", "other"}, true},
{"stop", []string{"suffix", "staging.mydomain.com", "coredns.rock", "answer", "auto"}, false},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "auto"}, false},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name"}, true},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name", "coredns.rock", "staging.mydomain.com"}, false},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name", "(.*).coredns.rock", "{1}.{2}.staging.mydomain.com"}, true},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com"}, false},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com", "answer", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com"}, false},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com", "name", "(.*).coredns.rock"}, true},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com", "value", "(.*).coredns.rock", "{1}.staging.mydomain.com"}, false},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com", "answer", "value", "(.*).coredns.rock", "{1}.staging.mydomain.com"}, false},
{"stop", []string{"regex", "staging.mydomain.com", "coredns.rock", "answer", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com", "value", "(.*).coredns.rock"}, true},
{"stop", []string{"suffix", "staging.mydomain.com.", "coredns.rock.", "answer", "value", "(.*).coredns.rock", "{1}.staging.mydomain.com", "value", "(.*).coredns.rock", "{1}.staging.mydomain.com"}, false},
{"stop", []string{"suffix", "staging.mydomain.com.", "coredns.rock.", "answer", "value", "(.*).coredns.rock", "{1}.staging.mydomain.com", "answer", "value", "(.*).coredns.rock", "{1}.staging.mydomain.com"}, false},
{"stop", []string{"suffix", "staging.mydomain.com.", "coredns.rock.", "answer", "value", "(.*).coredns.rock", "{1}.staging.mydomain.com", "name", "(.*).coredns.rock", "{1}.staging.mydomain.com"}, false},
{"stop", []string{"suffix", "staging.mydomain.com.", "coredns.rock.", "answer", "value", "(.*).coredns.rock", "{1}.staging.mydomain.com", "value", "(.*).coredns.rock"}, true},
}
for i, tc := range tests {
failed := false

137
plugin/rewrite/reverter.go
View File

@@ -1,37 +1,69 @@
package rewrite
import (
"regexp"
"strconv"
"strings"
"github.com/miekg/dns"
)
// ResponseRule contains a rule to rewrite a response with.
type ResponseRule struct {
Active bool
Type string
Pattern *regexp.Regexp
Replacement string
TTL uint32
// RevertPolicy controls the overall reverting process
type RevertPolicy interface {
DoRevert() bool
DoQuestionRestore() bool
}
type revertPolicy struct {
noRevert bool
noRestore bool
}
func (p revertPolicy) DoRevert() bool {
return !p.noRevert
}
func (p revertPolicy) DoQuestionRestore() bool {
return !p.noRestore
}
// NoRevertPolicy disables all response rewrite rules
func NoRevertPolicy() RevertPolicy {
return revertPolicy{true, false}
}
// NoRestorePolicy disables the question restoration during the response rewrite
func NoRestorePolicy() RevertPolicy {
return revertPolicy{false, true}
}
// NewRevertPolicy creates a new reverter policy by dynamically specifying all
// options.
func NewRevertPolicy(noRevert, noRestore bool) RevertPolicy {
return revertPolicy{noRestore: noRestore, noRevert: noRevert}
}
// ResponseRule contains a rule to rewrite a response with.
type ResponseRule interface {
RewriteResponse(rr dns.RR)
}
// ResponseRules describes an ordered list of response rules to apply
// after a name rewrite
type ResponseRules = []ResponseRule
// ResponseReverter reverses the operations done on the question section of a packet.
// This is need because the client will otherwise disregards the response, i.e.
// dig will complain with ';; Question section mismatch: got example.org/HINFO/IN'
type ResponseReverter struct {
dns.ResponseWriter
originalQuestion dns.Question
ResponseRewrite bool
ResponseRules []ResponseRule
ResponseRules ResponseRules
revertPolicy RevertPolicy
}
// NewResponseReverter returns a pointer to a new ResponseReverter.
func NewResponseReverter(w dns.ResponseWriter, r *dns.Msg) *ResponseReverter {
func NewResponseReverter(w dns.ResponseWriter, r *dns.Msg, policy RevertPolicy) *ResponseReverter {
return &ResponseReverter{
ResponseWriter: w,
originalQuestion: r.Question[0],
revertPolicy: policy,
}
}
@@ -40,61 +72,33 @@ func (r *ResponseReverter) WriteMsg(res1 *dns.Msg) error {
// Deep copy 'res' as to not (e.g). rewrite a message that's also stored in the cache.
res := res1.Copy()
res.Question[0] = r.originalQuestion
if r.ResponseRewrite {
if r.revertPolicy.DoQuestionRestore() {
res.Question[0] = r.originalQuestion
}
if len(r.ResponseRules) > 0 {
for _, rr := range res.Ns {
rewriteResourceRecord(res, rr, r)
r.rewriteResourceRecord(res, rr)
}
for _, rr := range res.Answer {
rewriteResourceRecord(res, rr, r)
r.rewriteResourceRecord(res, rr)
}
for _, rr := range res.Extra {
rewriteResourceRecord(res, rr, r)
r.rewriteResourceRecord(res, rr)
}
}
return r.ResponseWriter.WriteMsg(res)
}
func rewriteResourceRecord(res *dns.Msg, rr dns.RR, r *ResponseReverter) {
var (
isNameRewritten bool
isTTLRewritten bool
isValueRewritten bool
name = rr.Header().Name
ttl = rr.Header().Ttl
value string
)
func (r *ResponseReverter) rewriteResourceRecord(res *dns.Msg, rr dns.RR) {
for _, rule := range r.ResponseRules {
if rule.Type == "" {
rule.Type = "name"
}
switch rule.Type {
case "name":
rewriteString(rule, &name, &isNameRewritten)
case "value":
value = getRecordValueForRewrite(rr)
if value != "" {
rewriteString(rule, &value, &isValueRewritten)
}
case "ttl":
ttl = rule.TTL
isTTLRewritten = true
}
rule.RewriteResponse(rr)
}
}
if isNameRewritten {
rr.Header().Name = name
}
if isTTLRewritten {
rr.Header().Ttl = ttl
}
if isValueRewritten {
setRewrittenRecordValue(rr, value)
}
// Write is a wrapper that records the size of the message that gets written.
func (r *ResponseReverter) Write(buf []byte) (int, error) {
n, err := r.ResponseWriter.Write(buf)
return n, err
}
func getRecordValueForRewrite(rr dns.RR) (name string) {
@@ -136,24 +140,3 @@ func setRewrittenRecordValue(rr dns.RR, value string) {
rr.(*dns.SOA).Ns = value
}
}
func rewriteString(rule ResponseRule, str *string, isStringRewritten *bool) {
regexGroups := rule.Pattern.FindStringSubmatch(*str)
if len(regexGroups) == 0 {
return
}
s := rule.Replacement
for groupIndex, groupValue := range regexGroups {
groupIndexStr := "{" + strconv.Itoa(groupIndex) + "}"
s = strings.Replace(s, groupIndexStr, groupValue, -1)
}
*isStringRewritten = true
*str = s
}
// Write is a wrapper that records the size of the message that gets written.
func (r *ResponseReverter) Write(buf []byte) (int, error) {
n, err := r.ResponseWriter.Write(buf)
return n, err
}

86
plugin/rewrite/reverter_test.go
View File

@@ -53,9 +53,9 @@ func doReverterTests(rules []Rule, t *testing.T) {
m.Question[0].Qclass = dns.ClassINET
m.Answer = tc.answer
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
noRevert: tc.noRevert,
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
RevertPolicy: NewRevertPolicy(tc.noRevert, false),
}
rec := dnstest.NewRecorder(&test.ResponseWriter{})
rw.ServeDNS(ctx, rec, m)
@@ -81,38 +81,56 @@ var valueTests = []struct {
expectAnswerType uint16
expectAddlName string
}{
{"my.domain.uk", dns.TypeSRV, []dns.RR{test.SRV("my.cluster.local. 5 IN SRV 0 100 100 srv1.my.cluster.local.")}, []dns.RR{test.A("srv1.my.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk", dns.TypeSRV, false, "srv1.my.domain.uk.", dns.TypeSRV, "srv1.my.domain.uk."},
{"my.domain.uk", dns.TypeSRV, []dns.RR{test.SRV("my.cluster.local. 5 IN SRV 0 100 100 srv1.my.cluster.local.")}, []dns.RR{test.A("srv1.my.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeSRV, true, "srv1.my.cluster.local.", dns.TypeSRV, "srv1.my.cluster.local."},
{"my.domain.uk", dns.TypeANY, []dns.RR{test.CNAME("my.cluster.local. 3600 IN CNAME cname.cluster.local.")}, []dns.RR{test.A("cname.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk", dns.TypeANY, false, "cname.domain.uk.", dns.TypeCNAME, "cname.domain.uk."},
{"my.domain.uk", dns.TypeANY, []dns.RR{test.CNAME("my.cluster.local. 3600 IN CNAME cname.cluster.local.")}, []dns.RR{test.A("cname.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeANY, true, "cname.cluster.local.", dns.TypeCNAME, "cname.cluster.local."},
{"my.domain.uk", dns.TypeANY, []dns.RR{test.DNAME("my.cluster.local. 3600 IN DNAME dname.cluster.local.")}, []dns.RR{test.A("dname.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk", dns.TypeANY, false, "dname.domain.uk.", dns.TypeDNAME, "dname.domain.uk."},
{"my.domain.uk", dns.TypeANY, []dns.RR{test.DNAME("my.cluster.local. 3600 IN DNAME dname.cluster.local.")}, []dns.RR{test.A("dname.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeANY, true, "dname.cluster.local.", dns.TypeDNAME, "dname.cluster.local."},
{"my.domain.uk", dns.TypeMX, []dns.RR{test.MX("my.cluster.local. 3600 IN MX 1 mx1.cluster.local.")}, []dns.RR{test.A("mx1.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk", dns.TypeMX, false, "mx1.domain.uk.", dns.TypeMX, "mx1.domain.uk."},
{"my.domain.uk", dns.TypeMX, []dns.RR{test.MX("my.cluster.local. 3600 IN MX 1 mx1.cluster.local.")}, []dns.RR{test.A("mx1.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeMX, true, "mx1.cluster.local.", dns.TypeMX, "mx1.cluster.local."},
{"my.domain.uk", dns.TypeANY, []dns.RR{test.NS("my.cluster.local. 3600 IN NS ns1.cluster.local.")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk", dns.TypeANY, false, "ns1.domain.uk.", dns.TypeNS, "ns1.domain.uk."},
{"my.domain.uk", dns.TypeANY, []dns.RR{test.NS("my.cluster.local. 3600 IN NS ns1.cluster.local.")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeANY, true, "ns1.cluster.local.", dns.TypeNS, "ns1.cluster.local."},
{"my.domain.uk", dns.TypeSOA, []dns.RR{test.SOA("my.cluster.local. 1800 IN SOA ns1.cluster.local. admin.cluster.local. 1502165581 14400 3600 604800 14400")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk", dns.TypeSOA, false, "ns1.domain.uk.", dns.TypeSOA, "ns1.domain.uk."},
{"my.domain.uk", dns.TypeSOA, []dns.RR{test.SOA("my.cluster.local. 1800 IN SOA ns1.cluster.local. admin.cluster.local. 1502165581 14400 3600 604800 14400")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeSOA, true, "ns1.cluster.local.", dns.TypeSOA, "ns1.cluster.local."},
{"my.domain.uk", dns.TypeNAPTR, []dns.RR{test.NAPTR("my.cluster.local. 100 IN NAPTR 100 10 \"S\" \"SIP+D2U\" \"!^.*$!sip:customer-service@example.com!\" _sip._udp.cluster.local.")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk", dns.TypeNAPTR, false, "_sip._udp.domain.uk.", dns.TypeNAPTR, "ns1.domain.uk."},
{"my.domain.uk", dns.TypeNAPTR, []dns.RR{test.NAPTR("my.cluster.local. 100 IN NAPTR 100 10 \"S\" \"SIP+D2U\" \"!^.*$!sip:customer-service@example.com!\" _sip._udp.cluster.local.")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeNAPTR, true, "_sip._udp.cluster.local.", dns.TypeNAPTR, "ns1.cluster.local."},
{"my.domain.uk.", dns.TypeSRV, []dns.RR{test.SRV("my.cluster.local. 5 IN SRV 0 100 100 srv1.my.cluster.local.")}, []dns.RR{test.A("srv1.my.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk.", dns.TypeSRV, false, "srv1.my.domain.uk.", dns.TypeSRV, "srv1.my.domain.uk."},
{"my.domain.uk.", dns.TypeSRV, []dns.RR{test.SRV("my.cluster.local. 5 IN SRV 0 100 100 srv1.my.cluster.local.")}, []dns.RR{test.A("srv1.my.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeSRV, true, "srv1.my.cluster.local.", dns.TypeSRV, "srv1.my.cluster.local."},
{"my.domain.uk.", dns.TypeANY, []dns.RR{test.CNAME("my.cluster.local. 3600 IN CNAME cname.cluster.local.")}, []dns.RR{test.A("cname.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk.", dns.TypeANY, false, "cname.domain.uk.", dns.TypeCNAME, "cname.domain.uk."},
{"my.domain.uk.", dns.TypeANY, []dns.RR{test.CNAME("my.cluster.local. 3600 IN CNAME cname.cluster.local.")}, []dns.RR{test.A("cname.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeANY, true, "cname.cluster.local.", dns.TypeCNAME, "cname.cluster.local."},
{"my.domain.uk.", dns.TypeANY, []dns.RR{test.DNAME("my.cluster.local. 3600 IN DNAME dname.cluster.local.")}, []dns.RR{test.A("dname.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk.", dns.TypeANY, false, "dname.domain.uk.", dns.TypeDNAME, "dname.domain.uk."},
{"my.domain.uk.", dns.TypeANY, []dns.RR{test.DNAME("my.cluster.local. 3600 IN DNAME dname.cluster.local.")}, []dns.RR{test.A("dname.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeANY, true, "dname.cluster.local.", dns.TypeDNAME, "dname.cluster.local."},
{"my.domain.uk.", dns.TypeMX, []dns.RR{test.MX("my.cluster.local. 3600 IN MX 1 mx1.cluster.local.")}, []dns.RR{test.A("mx1.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk.", dns.TypeMX, false, "mx1.domain.uk.", dns.TypeMX, "mx1.domain.uk."},
{"my.domain.uk.", dns.TypeMX, []dns.RR{test.MX("my.cluster.local. 3600 IN MX 1 mx1.cluster.local.")}, []dns.RR{test.A("mx1.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeMX, true, "mx1.cluster.local.", dns.TypeMX, "mx1.cluster.local."},
{"my.domain.uk.", dns.TypeANY, []dns.RR{test.NS("my.cluster.local. 3600 IN NS ns1.cluster.local.")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk.", dns.TypeANY, false, "ns1.domain.uk.", dns.TypeNS, "ns1.domain.uk."},
{"my.domain.uk.", dns.TypeANY, []dns.RR{test.NS("my.cluster.local. 3600 IN NS ns1.cluster.local.")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeANY, true, "ns1.cluster.local.", dns.TypeNS, "ns1.cluster.local."},
{"my.domain.uk.", dns.TypeSOA, []dns.RR{test.SOA("my.cluster.local. 1800 IN SOA ns1.cluster.local. admin.cluster.local. 1502165581 14400 3600 604800 14400")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk.", dns.TypeSOA, false, "ns1.domain.uk.", dns.TypeSOA, "ns1.domain.uk."},
{"my.domain.uk.", dns.TypeSOA, []dns.RR{test.SOA("my.cluster.local. 1800 IN SOA ns1.cluster.local. admin.cluster.local. 1502165581 14400 3600 604800 14400")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeSOA, true, "ns1.cluster.local.", dns.TypeSOA, "ns1.cluster.local."},
{"my.domain.uk.", dns.TypeNAPTR, []dns.RR{test.NAPTR("my.cluster.local. 100 IN NAPTR 100 10 \"S\" \"SIP+D2U\" \"!^.*$!sip:customer-service@example.com!\" _sip._udp.cluster.local.")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.domain.uk.", dns.TypeNAPTR, false, "_sip._udp.domain.uk.", dns.TypeNAPTR, "ns1.domain.uk."},
{"my.domain.uk.", dns.TypeNAPTR, []dns.RR{test.NAPTR("my.cluster.local. 100 IN NAPTR 100 10 \"S\" \"SIP+D2U\" \"!^.*$!sip:customer-service@example.com!\" _sip._udp.cluster.local.")}, []dns.RR{test.A("ns1.cluster.local. 5 IN A 10.0.0.1")}, "my.cluster.local.", dns.TypeNAPTR, true, "_sip._udp.cluster.local.", dns.TypeNAPTR, "ns1.cluster.local."},
}
func TestValueResponseReverter(t *testing.T) {
rules := []Rule{}
r, _ := newNameRule("stop", "regex", `(.*)\.domain\.uk`, "{1}.cluster.local", "answer", "name", `(.*)\.cluster\.local`, "{1}.domain.uk", "answer", "value", `(.*)\.cluster\.local`, "{1}.domain.uk")
r, err := newNameRule("stop", "regex", `(.*)\.domain\.uk`, "{1}.cluster.local", "answer", "name", `(.*)\.cluster\.local`, "{1}.domain.uk", "answer", "value", `(.*)\.cluster\.local`, "{1}.domain.uk")
if err != nil {
t.Errorf("cannot parse rule: %s", err)
return
}
rules = append(rules, r)
doValueReverterTests(rules, t)
doValueReverterTests("stop", rules, t)
rules = []Rule{}
r, _ = newNameRule("continue", "regex", `(.*)\.domain\.uk`, "{1}.cluster.local", "answer", "name", `(.*)\.cluster\.local`, "{1}.domain.uk", "answer", "value", `(.*)\.cluster\.local`, "{1}.domain.uk")
r, err = newNameRule("continue", "regex", `(.*)\.domain\.uk`, "{1}.cluster.local", "answer", "name", `(.*)\.cluster\.local`, "{1}.domain.uk", "answer", "value", `(.*)\.cluster\.local`, "{1}.domain.uk")
if err != nil {
t.Errorf("cannot parse rule: %s", err)
return
}
rules = append(rules, r)
doValueReverterTests(rules, t)
doValueReverterTests("continue", rules, t)
rules = []Rule{}
r, err = newNameRule("stop", "suffix", `.domain.uk`, ".cluster.local", "answer", "auto", "answer", "value", `(.*)\.cluster\.local`, "{1}.domain.uk")
if err != nil {
t.Errorf("cannot parse rule: %s", err)
return
}
rules = append(rules, r)
doValueReverterTests("suffix", rules, t)
}
func doValueReverterTests(rules []Rule, t *testing.T) {
func doValueReverterTests(name string, rules []Rule, t *testing.T) {
ctx := context.TODO()
for i, tc := range valueTests {
m := new(dns.Msg)
@@ -121,37 +139,41 @@ func doValueReverterTests(rules []Rule, t *testing.T) {
m.Answer = tc.answer
m.Extra = tc.extra
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
noRevert: tc.noRevert,
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
RevertPolicy: NewRevertPolicy(tc.noRevert, false),
}
rec := dnstest.NewRecorder(&test.ResponseWriter{})
rw.ServeDNS(ctx, rec, m)
resp := rec.Msg
if resp.Question[0].Name != tc.to {
t.Errorf("Test %d: Expected Name to be %q but was %q", i, tc.to, resp.Question[0].Name)
t.Errorf("Test %s.%d: Expected Name to be %q but was %q", name, i, tc.to, resp.Question[0].Name)
}
if resp.Question[0].Qtype != tc.toType {
t.Errorf("Test %d: Expected Type to be '%d' but was '%d'", i, tc.toType, resp.Question[0].Qtype)
t.Errorf("Test %s.%d: Expected Type to be '%d' but was '%d'", name, i, tc.toType, resp.Question[0].Qtype)
}
if len(resp.Answer) <= 0 || resp.Answer[0].Header().Rrtype != tc.expectAnswerType {
t.Error("Unexpected Answer Record Type / No Answers")
if len(resp.Answer) <= 0 {
t.Errorf("Test %s.%d: No Answers", name, i)
return
}
if len(resp.Answer) > 0 && resp.Answer[0].Header().Rrtype != tc.expectAnswerType {
t.Errorf("Test %s.%d: Unexpected Answer Record Type %d", name, i, resp.Answer[0].Header().Rrtype)
return
}
value := getRecordValueForRewrite(resp.Answer[0])
if value != tc.expectValue {
t.Errorf("Test %d: Expected Target to be '%s' but was '%s'", i, tc.expectValue, value)
t.Errorf("Test %s.%d: Expected Target to be '%s' but was '%s'", name, i, tc.expectValue, value)
}
if len(resp.Extra) <= 0 || resp.Extra[0].Header().Rrtype != dns.TypeA {
t.Error("Unexpected Additional Record Type / No Additional Records")
t.Errorf("Test %s.%d: Unexpected Additional Record Type / No Additional Records", name, i)
return
}
if resp.Extra[0].Header().Name != tc.expectAddlName {
t.Errorf("Test %d: Expected Extra Name to be %q but was %q", i, tc.expectAddlName, resp.Extra[0].Header().Name)
t.Errorf("Test %s.%d: Expected Extra Name to be %q but was %q", name, i, tc.expectAddlName, resp.Extra[0].Header().Name)
}
}
}

34
plugin/rewrite/rewrite.go
View File

@@ -31,40 +31,34 @@ const (
// Rewrite is a plugin to rewrite requests internally before being handled.
type Rewrite struct {
Next plugin.Handler
Rules []Rule
noRevert bool
Next plugin.Handler
Rules []Rule
RevertPolicy
}
// ServeDNS implements the plugin.Handler interface.
func (rw Rewrite) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
wr := NewResponseReverter(w, r)
if rw.RevertPolicy == nil {
rw.RevertPolicy = NewRevertPolicy(false, false)
}
wr := NewResponseReverter(w, r, rw.RevertPolicy)
state := request.Request{W: w, Req: r}
for _, rule := range rw.Rules {
switch result := rule.Rewrite(ctx, state); result {
case RewriteDone:
respRules, result := rule.Rewrite(ctx, state)
if result == RewriteDone {
if _, ok := dns.IsDomainName(state.Req.Question[0].Name); !ok {
err := fmt.Errorf("invalid name after rewrite: %s", state.Req.Question[0].Name)
state.Req.Question[0] = wr.originalQuestion
return dns.RcodeServerFailure, err
}
for _, respRule := range rule.GetResponseRules() {
if respRule.Active {
wr.ResponseRewrite = true
wr.ResponseRules = append(wr.ResponseRules, respRule)
}
}
wr.ResponseRules = append(wr.ResponseRules, respRules...)
if rule.Mode() == Stop {
if rw.noRevert {
return plugin.NextOrFailure(rw.Name(), rw.Next, ctx, w, r)
}
return plugin.NextOrFailure(rw.Name(), rw.Next, ctx, wr, r)
break
}
case RewriteIgnored:
}
}
if rw.noRevert || len(wr.ResponseRules) == 0 {
if !rw.RevertPolicy.DoRevert() || len(wr.ResponseRules) == 0 {
return plugin.NextOrFailure(rw.Name(), rw.Next, ctx, w, r)
}
return plugin.NextOrFailure(rw.Name(), rw.Next, ctx, wr, r)
@@ -76,11 +70,9 @@ func (rw Rewrite) Name() string { return "rewrite" }
// Rule describes a rewrite rule.
type Rule interface {
// Rewrite rewrites the current request.
Rewrite(ctx context.Context, state request.Request) Result
Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result)
// Mode returns the processing mode stop or continue.
Mode() string
// GetResponseRules returns rules to rewrite response with, if any.
GetResponseRules() []ResponseRule
}
func newRule(args ...string) (Rule, error) {

32
plugin/rewrite/rewrite_test.go
View File

@@ -3,6 +3,7 @@ package rewrite
import (
"bytes"
"context"
"fmt"
"reflect"
"testing"
@@ -16,6 +17,11 @@ import (
)
func msgPrinter(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
if len(r.Answer) == 0 {
r.Answer = []dns.RR{
test.A(fmt.Sprintf("%s 5 IN A 10.0.0.1", r.Question[0].Name)),
}
}
w.WriteMsg(r)
return 0, nil
}
@@ -44,7 +50,7 @@ func TestNewRule(t *testing.T) {
{[]string{"name", "regex", "(cdns)\\.(core)\\.(rocks)", "{2}.{1}.{3}", "answer", "ttl", "(core)\\.(cdns)\\.(rocks)", "{2}.{1}.{3}"}, true, nil},
{[]string{"name", "regex", "(ddns)\\.(core)\\.(rocks)", "{2}.{1}.{3}", "answer", "name", "\xecore\\.(ddns)\\.(rocks)", "{2}.{1}.{3}"}, true, nil},
{[]string{"name", "regex", "\xedns\\.(core)\\.(rocks)", "{2}.{1}.{3}", "answer", "name", "(core)\\.(edns)\\.(rocks)", "{2}.{1}.{3}"}, true, nil},
{[]string{"name", "substring", "fcore.dns.rocks", "dns.fcore.rocks", "answer", "name", "(fcore)\\.(dns)\\.(rocks)", "{2}.{1}.{3}"}, true, nil},
{[]string{"name", "substring", "fcore.dns.rocks", "dns.fcore.rocks", "answer", "name", "(fcore)\\.(dns)\\.(rocks)", "{2}.{1}.{3}"}, false, reflect.TypeOf(&substringNameRule{})},
{[]string{"name", "substring", "a.com", "b.com", "c.com"}, true, nil},
{[]string{"type"}, true, nil},
{[]string{"type", "a"}, true, nil},
@@ -185,9 +191,9 @@ func TestRewrite(t *testing.T) {
rules = append(rules, r)
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
noRevert: true,
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
RevertPolicy: NoRevertPolicy(),
}
tests := []struct {
@@ -248,8 +254,8 @@ func TestRewrite(t *testing.T) {
func TestRewriteEDNS0Local(t *testing.T) {
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
noRevert: true,
Next: plugin.HandlerFunc(msgPrinter),
RevertPolicy: NoRevertPolicy(),
}
tests := []struct {
@@ -336,9 +342,9 @@ func TestEdns0LocalMultiRule(t *testing.T) {
rules = append(rules, r)
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
noRevert: true,
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
RevertPolicy: NoRevertPolicy(),
}
tests := []struct {
@@ -447,8 +453,8 @@ func (tp testProvider) Metadata(ctx context.Context, state request.Request) cont
func TestRewriteEDNS0LocalVariable(t *testing.T) {
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
noRevert: true,
Next: plugin.HandlerFunc(msgPrinter),
RevertPolicy: NoRevertPolicy(),
}
expectedMetadata := []metadata.Provider{
@@ -569,8 +575,8 @@ func TestRewriteEDNS0LocalVariable(t *testing.T) {
func TestRewriteEDNS0Subnet(t *testing.T) {
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
noRevert: true,
Next: plugin.HandlerFunc(msgPrinter),
RevertPolicy: NoRevertPolicy(),
}
tests := []struct {

4
plugin/rewrite/setup_test.go
View File

@@ -44,12 +44,12 @@ func TestParse(t *testing.T) {
`rewrite stop {
name regex foo bar
answer name bar foo
name baz qux
name baz
}`)
_, err = rewriteParse(c)
if err == nil {
t.Errorf("Expected error but got success for invalid response rewrite")
} else if !strings.Contains(err.Error(), "must consist only of") {
} else if !strings.Contains(err.Error(), "2 arguments required") {
t.Errorf("Got wrong error for invalid response rewrite: %v", err.Error())
}

168
plugin/rewrite/ttl.go
View File

@@ -9,81 +9,91 @@ import (
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/request"
//"github.com/miekg/dns"
"github.com/miekg/dns"
)
type ttlResponseRule struct {
TTL uint32
}
func (r *ttlResponseRule) RewriteResponse(rr dns.RR) {
rr.Header().Ttl = r.TTL
}
type ttlRuleBase struct {
nextAction string
response ttlResponseRule
}
func newTTLRuleBase(nextAction string, ttl uint32) ttlRuleBase {
return ttlRuleBase{
nextAction: nextAction,
response: ttlResponseRule{TTL: ttl},
}
}
func (rule *ttlRuleBase) responseRule(match bool) (ResponseRules, Result) {
if match {
return ResponseRules{&rule.response}, RewriteDone
}
return nil, RewriteIgnored
}
// Mode returns the processing nextAction
func (rule *ttlRuleBase) Mode() string { return rule.nextAction }
type exactTTLRule struct {
NextAction string
From string
ResponseRules []ResponseRule
ttlRuleBase
From string
}
type prefixTTLRule struct {
NextAction string
Prefix string
ResponseRules []ResponseRule
ttlRuleBase
Prefix string
}
type suffixTTLRule struct {
NextAction string
Suffix string
ResponseRules []ResponseRule
ttlRuleBase
Suffix string
}
type substringTTLRule struct {
NextAction string
Substring string
ResponseRules []ResponseRule
ttlRuleBase
Substring string
}
type regexTTLRule struct {
NextAction string
Pattern *regexp.Regexp
ResponseRules []ResponseRule
ttlRuleBase
Pattern *regexp.Regexp
}
// Rewrite rewrites the current request based upon exact match of the name
// in the question section of the request.
func (rule *exactTTLRule) Rewrite(ctx context.Context, state request.Request) Result {
if rule.From == state.Name() {
return RewriteDone
}
return RewriteIgnored
func (rule *exactTTLRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
return rule.responseRule(rule.From == state.Name())
}
// Rewrite rewrites the current request when the name begins with the matching string.
func (rule *prefixTTLRule) Rewrite(ctx context.Context, state request.Request) Result {
if strings.HasPrefix(state.Name(), rule.Prefix) {
return RewriteDone
}
return RewriteIgnored
func (rule *prefixTTLRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
return rule.responseRule(strings.HasPrefix(state.Name(), rule.Prefix))
}
// Rewrite rewrites the current request when the name ends with the matching string.
func (rule *suffixTTLRule) Rewrite(ctx context.Context, state request.Request) Result {
if strings.HasSuffix(state.Name(), rule.Suffix) {
return RewriteDone
}
return RewriteIgnored
func (rule *suffixTTLRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
return rule.responseRule(strings.HasSuffix(state.Name(), rule.Suffix))
}
// Rewrite rewrites the current request based upon partial match of the
// name in the question section of the request.
func (rule *substringTTLRule) Rewrite(ctx context.Context, state request.Request) Result {
if strings.Contains(state.Name(), rule.Substring) {
return RewriteDone
}
return RewriteIgnored
func (rule *substringTTLRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
return rule.responseRule(strings.Contains(state.Name(), rule.Substring))
}
// Rewrite rewrites the current request when the name in the question
// section of the request matches a regular expression.
func (rule *regexTTLRule) Rewrite(ctx context.Context, state request.Request) Result {
regexGroups := rule.Pattern.FindStringSubmatch(state.Name())
if len(regexGroups) == 0 {
return RewriteIgnored
}
return RewriteDone
func (rule *regexTTLRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
return rule.responseRule(len(rule.Pattern.FindStringSubmatch(state.Name())) != 0)
}
// newTTLRule creates a name matching rule based on exact, partial, or regex match
@@ -106,43 +116,23 @@ func newTTLRule(nextAction string, args ...string) (Rule, error) {
switch strings.ToLower(args[0]) {
case ExactMatch:
return &exactTTLRule{
nextAction,
newTTLRuleBase(nextAction, ttl),
plugin.Name(args[1]).Normalize(),
[]ResponseRule{{
Active: true,
Type: "ttl",
TTL: ttl,
}},
}, nil
case PrefixMatch:
return &prefixTTLRule{
nextAction,
newTTLRuleBase(nextAction, ttl),
plugin.Name(args[1]).Normalize(),
[]ResponseRule{{
Active: true,
Type: "ttl",
TTL: ttl,
}},
}, nil
case SuffixMatch:
return &suffixTTLRule{
nextAction,
newTTLRuleBase(nextAction, ttl),
plugin.Name(args[1]).Normalize(),
[]ResponseRule{{
Active: true,
Type: "ttl",
TTL: ttl,
}},
}, nil
case SubstringMatch:
return &substringTTLRule{
nextAction,
newTTLRuleBase(nextAction, ttl),
plugin.Name(args[1]).Normalize(),
[]ResponseRule{{
Active: true,
Type: "ttl",
TTL: ttl,
}},
}, nil
case RegexMatch:
regexPattern, err := regexp.Compile(args[1])
@@ -150,13 +140,8 @@ func newTTLRule(nextAction string, args ...string) (Rule, error) {
return nil, fmt.Errorf("invalid regex pattern in a ttl rule: %s", args[1])
}
return &regexTTLRule{
nextAction,
newTTLRuleBase(nextAction, ttl),
regexPattern,
[]ResponseRule{{
Active: true,
Type: "ttl",
TTL: ttl,
}},
}, nil
default:
return nil, fmt.Errorf("ttl rule supports only exact, prefix, suffix, substring, and regex name matching")
@@ -166,48 +151,11 @@ func newTTLRule(nextAction string, args ...string) (Rule, error) {
return nil, fmt.Errorf("many few arguments for a ttl rule")
}
return &exactTTLRule{
nextAction,
newTTLRuleBase(nextAction, ttl),
plugin.Name(args[0]).Normalize(),
[]ResponseRule{{
Active: true,
Type: "ttl",
TTL: ttl,
}},
}, nil
}
// Mode returns the processing nextAction
func (rule *exactTTLRule) Mode() string { return rule.NextAction }
func (rule *prefixTTLRule) Mode() string { return rule.NextAction }
func (rule *suffixTTLRule) Mode() string { return rule.NextAction }
func (rule *substringTTLRule) Mode() string { return rule.NextAction }
func (rule *regexTTLRule) Mode() string { return rule.NextAction }
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *exactTTLRule) GetResponseRules() []ResponseRule {
return rule.ResponseRules
}
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *prefixTTLRule) GetResponseRules() []ResponseRule {
return rule.ResponseRules
}
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *suffixTTLRule) GetResponseRules() []ResponseRule {
return rule.ResponseRules
}
// GetResponseRules returns rules to rewrite the response with. Currently not implemented.
func (rule *substringTTLRule) GetResponseRules() []ResponseRule {
return rule.ResponseRules
}
// GetResponseRules returns rules to rewrite the response with.
func (rule *regexTTLRule) GetResponseRules() []ResponseRule {
return rule.ResponseRules
}
// validTTL returns true if v is valid TTL value.
func isValidTTL(v string) (uint32, bool) {
i, err := strconv.Atoi(v)

5
plugin/rewrite/ttl_test.go
View File

@@ -121,9 +121,8 @@ func doTTLTests(rules []Rule, t *testing.T) {
m.Question[0].Qclass = dns.ClassINET
m.Answer = tc.answer
rw := Rewrite{
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
noRevert: false,
Next: plugin.HandlerFunc(msgPrinter),
Rules: rules,
}
rec := dnstest.NewRecorder(&test.ResponseWriter{})
rw.ServeDNS(ctx, rec, m)

9
plugin/rewrite/type.go
View File

@@ -31,18 +31,15 @@ func newTypeRule(nextAction string, args ...string) (Rule, error) {
}
// Rewrite rewrites the current request.
func (rule *typeRule) Rewrite(ctx context.Context, state request.Request) Result {
func (rule *typeRule) Rewrite(ctx context.Context, state request.Request) (ResponseRules, Result) {
if rule.fromType > 0 && rule.toType > 0 {
if state.QType() == rule.fromType {
state.Req.Question[0].Qtype = rule.toType
return RewriteDone
return nil, RewriteDone
}
}
return RewriteIgnored
return nil, RewriteIgnored
}
// Mode returns the processing mode.
func (rule *typeRule) Mode() string { return rule.nextAction }
// GetResponseRules return rules to rewrite the response with. Currently not implemented.
func (rule *typeRule) GetResponseRules() []ResponseRule { return []ResponseRule{} }