Condition, rules, state and action refactor / rewrite

Add nested rules
Add backend action, allow wildcard in backends
Remove poison from tree, update README with action table

Allow defining pass/fail actions on challenge,

Remove redirect/referer parameters on backend pass

Set challenge cookie tied to host

Rewrite DNSBL condition into a challenge

Allow passing an arbitrary path for assets to js challenges

Optimize programs exhaustively on compilation

Activation instead of map for CEL context, faster map access, new network override

Return valid host on cookie setting in case Host is an IP address.
bug: does not work with IPv6, see https://github.com/golang/go/issues/65521

Apply TLS fingerprinter on GetConfigForClient instead of GetCertificate

Cleanup go-away cookies before passing to backend

Code action for specifically replying with an HTTP code

lib/challenge/dnsbl/dnsbl.go

@@ -0,0 +1,149 @@
+package http
+
+import (
+	"context"
+	"errors"
+	"git.gammaspectra.live/git/go-away/lib/challenge"
+	"git.gammaspectra.live/git/go-away/utils"
+	"github.com/goccy/go-yaml"
+	"github.com/goccy/go-yaml/ast"
+	"net"
+	"net/http"
+	"time"
+)
+
+func init() {
+	challenge.Runtimes[Key] = FillRegistration
+}
+
+const Key = "dnsbl"
+
+type Parameters struct {
+	VerifyProbability float64       `yaml:"verify-probability"`
+	Host              string        `yaml:"dnsbl-host"`
+	Timeout           time.Duration `yaml:"dnsbl-timeout"`
+	Decay             time.Duration `yaml:"dnsbl-decay"`
+}
+
+var DefaultParameters = Parameters{
+	VerifyProbability: 0.10,
+	Timeout:           time.Second * 1,
+	Decay:             time.Hour * 1,
+	Host:              "dnsbl.dronebl.org",
+}
+
+func lookup(ctx context.Context, decay, timeout time.Duration, dnsbl *utils.DNSBL, decayMap *utils.DecayMap[[net.IPv6len]byte, utils.DNSBLResponse], ip net.IP) (utils.DNSBLResponse, error) {
+	var key [net.IPv6len]byte
+	copy(key[:], ip.To16())
+
+	result, ok := decayMap.Get(key)
+	if ok {
+		return result, nil
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	result, err := dnsbl.Lookup(ctx, ip)
+	if err != nil {
+
+	}
+	decayMap.Set(key, result, decay)
+
+	return result, err
+}
+
+type closer chan struct{}
+
+func (c closer) Close() error {
+	select {
+	case <-c:
+	default:
+		close(c)
+	}
+	return nil
+}
+
+func FillRegistration(state challenge.StateInterface, reg *challenge.Registration, parameters ast.Node) error {
+	params := DefaultParameters
+
+	if parameters != nil {
+		ymlData, err := parameters.MarshalYAML()
+		if err != nil {
+			return err
+		}
+		err = yaml.Unmarshal(ymlData, &params)
+		if err != nil {
+			return err
+		}
+	}
+
+	if params.Host == "" {
+		return errors.New("empty host")
+	}
+
+	reg.Class = challenge.ClassTransparent
+
+	if params.VerifyProbability <= 0 {
+		//20% default
+		params.VerifyProbability = 0.20
+	} else if params.VerifyProbability > 1.0 {
+		params.VerifyProbability = 1.0
+	}
+	reg.VerifyProbability = params.VerifyProbability
+
+	decayMap := utils.NewDecayMap[[net.IPv6len]byte, utils.DNSBLResponse]()
+
+	dnsbl := utils.NewDNSBL(params.Host, &net.Resolver{
+		PreferGo: true,
+	})
+
+	ob := make(closer)
+
+	go func() {
+		ticker := time.NewTicker(params.Timeout / 3)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-ticker.C:
+				decayMap.Decay()
+			case <-ob:
+				return
+			}
+		}
+	}()
+
+	// allow freeing the ticker/decay map
+	reg.Object = ob
+
+	reg.IssueChallenge = func(w http.ResponseWriter, r *http.Request, key challenge.Key, expiry time.Time) challenge.VerifyResult {
+
+		data := challenge.RequestDataFromContext(r.Context())
+
+		result, err := lookup(r.Context(), params.Decay, params.Timeout, dnsbl, decayMap, data.RemoteAddress)
+		if err != nil {
+			data.State.Logger(r).Debug("dnsbl lookup failed", "address", data.RemoteAddress.String(), "result", result, "err", err)
+		}
+
+		if err != nil {
+			return challenge.VerifyResultFail
+		}
+
+		if result.Bad() {
+			token, err := reg.IssueChallengeToken(state.PrivateKey(), key, nil, expiry, false)
+			if err != nil {
+				return challenge.VerifyResultFail
+			}
+			utils.SetCookie(utils.CookiePrefix+reg.Name, token, expiry, w, r)
+			return challenge.VerifyResultNotOK
+		} else {
+			token, err := reg.IssueChallengeToken(state.PrivateKey(), key, nil, expiry, true)
+			if err != nil {
+				return challenge.VerifyResultFail
+			}
+			utils.SetCookie(utils.CookiePrefix+reg.Name, token, expiry, w, r)
+			return challenge.VerifyResultOK
+		}
+	}
+
+	return nil
+}