118 lines
3.2 KiB
Go
118 lines
3.2 KiB
Go
package tcpmiddleware
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import (
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"context"
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"fmt"
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"strings"
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"github.com/traefik/traefik/v3/pkg/config/runtime"
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"github.com/traefik/traefik/v3/pkg/middlewares/tcp/inflightconn"
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"github.com/traefik/traefik/v3/pkg/middlewares/tcp/ipallowlist"
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"github.com/traefik/traefik/v3/pkg/server/provider"
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"github.com/traefik/traefik/v3/pkg/tcp"
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)
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type middlewareStackType int
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const (
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middlewareStackKey middlewareStackType = iota
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)
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// Builder the middleware builder.
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type Builder struct {
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configs map[string]*runtime.TCPMiddlewareInfo
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}
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// NewBuilder creates a new Builder.
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func NewBuilder(configs map[string]*runtime.TCPMiddlewareInfo) *Builder {
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return &Builder{configs: configs}
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}
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// BuildChain creates a middleware chain.
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func (b *Builder) BuildChain(ctx context.Context, middlewares []string) *tcp.Chain {
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chain := tcp.NewChain()
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for _, name := range middlewares {
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middlewareName := provider.GetQualifiedName(ctx, name)
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chain = chain.Append(func(next tcp.Handler) (tcp.Handler, error) {
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constructorContext := provider.AddInContext(ctx, middlewareName)
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if midInf, ok := b.configs[middlewareName]; !ok || midInf.TCPMiddleware == nil {
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return nil, fmt.Errorf("middleware %q does not exist", middlewareName)
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}
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var err error
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if constructorContext, err = checkRecursion(constructorContext, middlewareName); err != nil {
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b.configs[middlewareName].AddError(err, true)
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return nil, err
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}
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constructor, err := b.buildConstructor(constructorContext, middlewareName)
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if err != nil {
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b.configs[middlewareName].AddError(err, true)
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return nil, err
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}
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handler, err := constructor(next)
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if err != nil {
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b.configs[middlewareName].AddError(err, true)
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return nil, err
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}
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return handler, nil
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})
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}
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return &chain
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}
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func checkRecursion(ctx context.Context, middlewareName string) (context.Context, error) {
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currentStack, ok := ctx.Value(middlewareStackKey).([]string)
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if !ok {
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currentStack = []string{}
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}
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if inSlice(middlewareName, currentStack) {
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return ctx, fmt.Errorf("could not instantiate middleware %s: recursion detected in %s", middlewareName, strings.Join(append(currentStack, middlewareName), "->"))
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}
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return context.WithValue(ctx, middlewareStackKey, append(currentStack, middlewareName)), nil
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}
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func (b *Builder) buildConstructor(ctx context.Context, middlewareName string) (tcp.Constructor, error) {
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config := b.configs[middlewareName]
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if config == nil || config.TCPMiddleware == nil {
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return nil, fmt.Errorf("invalid middleware %q configuration", middlewareName)
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}
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var middleware tcp.Constructor
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// InFlightConn
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if config.InFlightConn != nil {
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middleware = func(next tcp.Handler) (tcp.Handler, error) {
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return inflightconn.New(ctx, next, *config.InFlightConn, middlewareName)
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}
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}
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// IPAllowList
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if config.IPAllowList != nil {
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middleware = func(next tcp.Handler) (tcp.Handler, error) {
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return ipallowlist.New(ctx, next, *config.IPAllowList, middlewareName)
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}
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}
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if middleware == nil {
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return nil, fmt.Errorf("invalid middleware %q configuration: invalid middleware type or middleware does not exist", middlewareName)
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}
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return middleware, nil
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}
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func inSlice(element string, stack []string) bool {
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for _, value := range stack {
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if value == element {
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return true
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}
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}
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return false
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}
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