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MINOR: config: add option forwarded support
Add support for the RFC 7239 "option forwarded" directive, which HAProxy uses to insert a Forwarded header field. The config-parser gains an OptionForwarded parser implementing the documented grammar: option forwarded [ proto ] [ host | host-expr <expr> ] [ by | by-expr <expr> ] [ by_port | by_port-expr <expr> ] [ for | for-expr <expr> ] [ for_port | for_port-expr <expr> ] along with "no option forwarded". Each parameter family is mutually exclusive between its boolean and its expression form, and may only appear once; violations are rejected at parse time. The parser is registered for the defaults, frontend, backend and listen sections. The generator learns a //set:validate:<func> directive so a parser can run a validation function before Set() stores data. This keeps the grammar constraints enforced when the type is populated programmatically and not only when a config line is parsed. Only OptionForwarded uses it, so no other generated parser changes. A typed Forwarded model is added to the specification and wired into defaults, frontend and backend, and mapped through the structured configuration in both directions, with the same mutual-exclusion checks applied to the model before it is serialized.
1 parent a33f598 commit df1681f

40 files changed

Lines changed: 2115 additions & 6 deletions

‎config-parser/generate/config-file.go‎

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@@ -76,6 +76,7 @@ type Data struct {
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HasAlias bool
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HasDefault bool
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HasTable bool
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SetValidator string // function used to validate data before Set stores it
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}
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type ConfigFile struct {

‎config-parser/generate/normal.tmpl‎

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@@ -184,8 +184,18 @@ func (p *{{ .StructName }}) Set(data common.ParserData, index int) error {
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{{- else }}
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switch newValue := data.(type) {
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case *types.{{ .ParserType }}:
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{{- if not (eq .SetValidator "") }}
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if err := {{ .SetValidator }}(newValue); err != nil {
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return err
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}
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{{- end }}
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p.data = newValue
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case types.{{ .ParserType }}:
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{{- if not (eq .SetValidator "") }}
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if err := {{ .SetValidator }}(&newValue); err != nil {
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return err
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}
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{{- end }}
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p.data = &newValue
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default:
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return errors.ErrInvalidData

‎config-parser/generate/types-normal.go‎

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@@ -68,6 +68,9 @@ func generateTypes(dir string, dataDir string) { //nolint:gocognit
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if strings.HasPrefix(line, "//no:parse") {
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parserData.NoParse = true
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}
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if after, ok := strings.CutPrefix(line, "//set:validate:"); ok {
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parserData.SetValidator = strings.TrimSpace(after)
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}
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if strings.HasPrefix(line, `//test:quote_ok`) && !parserData.Deprecated {
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data := strings.SplitN(line, ":", 3)
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parserData.TestOKEscaped = append(parserData.TestOKEscaped, data[2])

‎config-parser/parsers/option-forwarded.go‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,292 @@
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/*
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Copyright 2026 HAProxy Technologies
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package parsers
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import (
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"strings"
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"github.com/haproxytech/client-native/v6/config-parser/common"
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"github.com/haproxytech/client-native/v6/config-parser/errors"
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"github.com/haproxytech/client-native/v6/config-parser/types"
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)
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type OptionForwardedAttributeName string
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const (
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optionForwardedHost OptionForwardedAttributeName = "host"
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optionForwardedHostExpr OptionForwardedAttributeName = "host-expr"
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optionForwardedBy OptionForwardedAttributeName = "by"
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optionForwardedByExpr OptionForwardedAttributeName = "by-expr"
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optionForwardedByPort OptionForwardedAttributeName = "by_port"
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optionForwardedByPortExp OptionForwardedAttributeName = "by_port-expr"
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optionForwardedFor OptionForwardedAttributeName = "for"
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optionForwardedForExpr OptionForwardedAttributeName = "for-expr"
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optionForwardedForPort OptionForwardedAttributeName = "for_port"
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optionForwardedForPortEx OptionForwardedAttributeName = "for_port-expr"
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optionForwardedProto OptionForwardedAttributeName = "proto"
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)
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type OptionForwarded struct {
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data *types.OptionForwarded
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preComments []string // comments that appear before the actual line
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}
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type optionForwardedAttribute struct {
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family OptionForwardedAttributeName
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needsValue bool
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set func(*types.OptionForwarded, string)
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}
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func optionForwardedAttributeByName(name OptionForwardedAttributeName) (optionForwardedAttribute, bool) {
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switch name {
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case optionForwardedProto:
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return optionForwardedAttribute{
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family: optionForwardedProto,
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set: func(data *types.OptionForwarded, _ string) {
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data.Proto = true
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},
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}, true
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case optionForwardedHost:
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return optionForwardedAttribute{
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family: optionForwardedHost,
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set: func(data *types.OptionForwarded, _ string) {
67+
data.Host = true
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},
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}, true
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case optionForwardedHostExpr:
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return optionForwardedAttribute{
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family: optionForwardedHost,
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needsValue: true,
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set: func(data *types.OptionForwarded, value string) { data.HostExpr = value },
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}, true
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case optionForwardedBy:
77+
return optionForwardedAttribute{
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family: optionForwardedBy,
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set: func(data *types.OptionForwarded, _ string) {
80+
data.By = true
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},
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}, true
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case optionForwardedByExpr:
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return optionForwardedAttribute{
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family: optionForwardedBy,
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needsValue: true,
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set: func(data *types.OptionForwarded, value string) { data.ByExpr = value },
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}, true
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case optionForwardedByPort:
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return optionForwardedAttribute{
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family: optionForwardedByPort,
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set: func(data *types.OptionForwarded, _ string) {
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data.ByPort = true
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},
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}, true
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case optionForwardedByPortExp:
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return optionForwardedAttribute{
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family: optionForwardedByPort,
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needsValue: true,
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set: func(data *types.OptionForwarded, value string) { data.ByPortExpr = value },
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}, true
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case optionForwardedFor:
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return optionForwardedAttribute{
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family: optionForwardedFor,
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set: func(data *types.OptionForwarded, _ string) {
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data.For = true
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},
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}, true
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case optionForwardedForExpr:
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return optionForwardedAttribute{
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family: optionForwardedFor,
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needsValue: true,
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set: func(data *types.OptionForwarded, value string) { data.ForExpr = value },
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}, true
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case optionForwardedForPort:
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return optionForwardedAttribute{
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family: optionForwardedForPort,
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set: func(data *types.OptionForwarded, _ string) {
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data.ForPort = true
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},
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}, true
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case optionForwardedForPortEx:
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return optionForwardedAttribute{
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family: optionForwardedForPort,
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needsValue: true,
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set: func(data *types.OptionForwarded, value string) { data.ForPortExpr = value },
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}, true
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default:
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return optionForwardedAttribute{}, false
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}
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}
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/*
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option forwarded [ proto ] [ host | host-expr <host_expr> ] [ by | by-expr <by_expr> ] [ by_port | by_port-expr <by_port_expr>] [ for | for-expr <for_expr> ] [ for_port | for_port-expr <for_port_expr>]
135+
*/
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func (s *OptionForwarded) Parse(line string, parts []string, comment string) (string, error) {
137+
if len(parts) > 2 && parts[0] == "no" && parts[1] == "option" && parts[2] == "forwarded" {
138+
if len(parts) != 3 {
139+
return "", errors.ErrInvalidData
140+
}
141+
s.data = &types.OptionForwarded{
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NoOption: true,
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Comment: comment,
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}
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return "", nil
146+
}
147+
if len(parts) > 1 && parts[0] == "option" && parts[1] == "forwarded" {
148+
data := &types.OptionForwarded{
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Comment: comment,
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}
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if err := parseOptionForwardedAttributes(data, parts[2:]); err != nil {
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return "", err
153+
}
154+
if err := validateOptionForwarded(data); err != nil {
155+
return "", err
156+
}
157+
s.data = data
158+
return "", nil
159+
}
160+
return "", &errors.ParseError{Parser: "option forwarded", Line: line}
161+
}
162+
163+
func parseOptionForwardedAttributes(data *types.OptionForwarded, parts []string) error {
164+
families := map[OptionForwardedAttributeName]bool{}
165+
for index := 0; index < len(parts); index++ {
166+
attribute, ok := optionForwardedAttributeByName(OptionForwardedAttributeName(parts[index]))
167+
if !ok {
168+
return errors.ErrInvalidData
169+
}
170+
if alreadyParsedOptionForwardedFamily(families, attribute.family) {
171+
return errors.ErrInvalidData
172+
}
173+
value := ""
174+
if attribute.needsValue {
175+
index++
176+
if index == len(parts) {
177+
return errors.ErrInvalidData
178+
}
179+
value = parts[index]
180+
}
181+
attribute.set(data, value)
182+
}
183+
return nil
184+
}
185+
186+
func alreadyParsedOptionForwardedFamily(families map[OptionForwardedAttributeName]bool, family OptionForwardedAttributeName) bool {
187+
if families[family] {
188+
return true
189+
}
190+
families[family] = true
191+
return false
192+
}
193+
194+
func validateOptionForwarded(data *types.OptionForwarded) error {
195+
if data == nil {
196+
return errors.ErrInvalidData
197+
}
198+
if data.NoOption {
199+
if data.Proto || data.Host || data.HostExpr != "" || data.By || data.ByExpr != "" ||
200+
data.ByPort || data.ByPortExpr != "" || data.For || data.ForExpr != "" ||
201+
data.ForPort || data.ForPortExpr != "" {
202+
return errors.ErrInvalidData
203+
}
204+
return nil
205+
}
206+
if data.Host && data.HostExpr != "" {
207+
return errors.ErrInvalidData
208+
}
209+
if data.By && data.ByExpr != "" {
210+
return errors.ErrInvalidData
211+
}
212+
if data.ByPort && data.ByPortExpr != "" {
213+
return errors.ErrInvalidData
214+
}
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if data.For && data.ForExpr != "" {
216+
return errors.ErrInvalidData
217+
}
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if data.ForPort && data.ForPortExpr != "" {
219+
return errors.ErrInvalidData
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}
221+
return nil
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}
223+
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func (s *OptionForwarded) Result() ([]common.ReturnResultLine, error) {
225+
if s.data == nil {
226+
return nil, errors.ErrFetch
227+
}
228+
if err := validateOptionForwarded(s.data); err != nil {
229+
return nil, err
230+
}
231+
var sb strings.Builder
232+
if s.data.NoOption {
233+
sb.WriteString("no ")
234+
}
235+
sb.WriteString("option forwarded")
236+
if !s.data.NoOption {
237+
writeOptionForwardedAttributes(&sb, s.data)
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}
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return []common.ReturnResultLine{
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{
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Data: sb.String(),
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Comment: s.data.Comment,
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},
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}, nil
245+
}
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func writeOptionForwardedAttributes(sb *strings.Builder, data *types.OptionForwarded) {
248+
if data.Proto {
249+
writeOptionForwardedAttribute(sb, optionForwardedProto)
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}
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if data.Host {
252+
writeOptionForwardedAttribute(sb, optionForwardedHost)
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}
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if data.HostExpr != "" {
255+
writeOptionForwardedAttributeValue(sb, optionForwardedHostExpr, data.HostExpr)
256+
}
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if data.By {
258+
writeOptionForwardedAttribute(sb, optionForwardedBy)
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}
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if data.ByExpr != "" {
261+
writeOptionForwardedAttributeValue(sb, optionForwardedByExpr, data.ByExpr)
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}
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if data.ByPort {
264+
writeOptionForwardedAttribute(sb, optionForwardedByPort)
265+
}
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if data.ByPortExpr != "" {
267+
writeOptionForwardedAttributeValue(sb, optionForwardedByPortExp, data.ByPortExpr)
268+
}
269+
if data.For {
270+
writeOptionForwardedAttribute(sb, optionForwardedFor)
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}
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if data.ForExpr != "" {
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writeOptionForwardedAttributeValue(sb, optionForwardedForExpr, data.ForExpr)
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}
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if data.ForPort {
276+
writeOptionForwardedAttribute(sb, optionForwardedForPort)
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}
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if data.ForPortExpr != "" {
279+
writeOptionForwardedAttributeValue(sb, optionForwardedForPortEx, data.ForPortExpr)
280+
}
281+
}
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func writeOptionForwardedAttribute(sb *strings.Builder, name OptionForwardedAttributeName) {
284+
sb.WriteString(" ")
285+
sb.WriteString(string(name))
286+
}
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288+
func writeOptionForwardedAttributeValue(sb *strings.Builder, name OptionForwardedAttributeName, value string) {
289+
writeOptionForwardedAttribute(sb, name)
290+
sb.WriteString(" ")
291+
sb.WriteString(value)
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}

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