traefik/pkg/middlewares/ipallowlist/ip_allowlist.go
2022-10-26 17:16:05 +02:00

88 lines
2.3 KiB
Go

package ipallowlist
import (
"context"
"errors"
"fmt"
"net/http"
"github.com/opentracing/opentracing-go/ext"
"github.com/traefik/traefik/v2/pkg/config/dynamic"
"github.com/traefik/traefik/v2/pkg/ip"
"github.com/traefik/traefik/v2/pkg/log"
"github.com/traefik/traefik/v2/pkg/middlewares"
"github.com/traefik/traefik/v2/pkg/tracing"
)
const (
typeName = "IPAllowLister"
)
// ipAllowLister is a middleware that provides Checks of the Requesting IP against a set of Allowlists.
type ipAllowLister struct {
next http.Handler
allowLister *ip.Checker
strategy ip.Strategy
name string
}
// New builds a new IPAllowLister given a list of CIDR-Strings to allow.
func New(ctx context.Context, next http.Handler, config dynamic.IPAllowList, name string) (http.Handler, error) {
logger := log.FromContext(middlewares.GetLoggerCtx(ctx, name, typeName))
logger.Debug("Creating middleware")
if len(config.SourceRange) == 0 {
return nil, errors.New("sourceRange is empty, IPAllowLister not created")
}
checker, err := ip.NewChecker(config.SourceRange)
if err != nil {
return nil, fmt.Errorf("cannot parse CIDRs %s: %w", config.SourceRange, err)
}
strategy, err := config.IPStrategy.Get()
if err != nil {
return nil, err
}
logger.Debugf("Setting up IPAllowLister with sourceRange: %s", config.SourceRange)
return &ipAllowLister{
strategy: strategy,
allowLister: checker,
next: next,
name: name,
}, nil
}
func (al *ipAllowLister) GetTracingInformation() (string, ext.SpanKindEnum) {
return al.name, tracing.SpanKindNoneEnum
}
func (al *ipAllowLister) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
ctx := middlewares.GetLoggerCtx(req.Context(), al.name, typeName)
logger := log.FromContext(ctx)
clientIP := al.strategy.GetIP(req)
err := al.allowLister.IsAuthorized(clientIP)
if err != nil {
msg := fmt.Sprintf("Rejecting IP %s: %v", clientIP, err)
logger.Debug(msg)
tracing.SetErrorWithEvent(req, msg)
reject(ctx, rw)
return
}
logger.Debugf("Accepting IP %s", clientIP)
al.next.ServeHTTP(rw, req)
}
func reject(ctx context.Context, rw http.ResponseWriter) {
statusCode := http.StatusForbidden
rw.WriteHeader(statusCode)
_, err := rw.Write([]byte(http.StatusText(statusCode)))
if err != nil {
log.FromContext(ctx).Error(err)
}
}