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/preload-link/preload-link.go

@@ -0,0 +1,128 @@
+package preload_link
+
+import (
+	"context"
+	"fmt"
+	"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/http"
+	"time"
+)
+
+func init() {
+	challenge.Runtimes[Key] = FillRegistration
+}
+
+const Key = "preload-link"
+
+type Parameters struct {
+	Deadline time.Duration `yaml:"preload-early-hint-deadline"`
+}
+
+var DefaultParameters = Parameters{
+	Deadline: time.Second * 3,
+}
+
+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
+		}
+	}
+
+	verifier, issuer := challenge.NewKeyVerifier()
+	reg.Verify = verifier
+
+	reg.Class = challenge.ClassTransparent
+
+	ob := challenge.NewAwaiter[string]()
+
+	reg.Object = ob
+
+	reg.IssueChallenge = func(w http.ResponseWriter, r *http.Request, key challenge.Key, expiry time.Time) challenge.VerifyResult {
+		// this only works on HTTP/2 and HTTP/3
+
+		if r.ProtoMajor < 2 {
+			// this can happen if we are an upgraded request from HTTP/1.1 to HTTP/2 in H2C
+			if _, ok := w.(http.Pusher); !ok {
+				return challenge.VerifyResultSkip
+			}
+		}
+
+		issuerKey := issuer(key)
+
+		uri, err := challenge.VerifyUrl(r, reg, issuerKey)
+		if err != nil {
+			return challenge.VerifyResultFail
+		}
+
+		// remove redirect args
+		values := uri.Query()
+		values.Del(challenge.QueryArgRedirect)
+		uri.RawQuery = values.Encode()
+
+		// Redirect URI must be absolute to work
+		uri.Scheme = utils.GetRequestScheme(r)
+		uri.Host = r.Host
+
+		w.Header().Set("Link", fmt.Sprintf("<%s>; rel=\"preload\"; as=\"style\"; fetchpriority=high", uri.String()))
+		defer func() {
+			// remove old header so it won't show on response!
+			w.Header().Del("Link")
+		}()
+		w.WriteHeader(http.StatusEarlyHints)
+
+		ctx, cancel := context.WithTimeout(r.Context(), params.Deadline)
+		defer cancel()
+		if result := ob.Await(issuerKey, ctx); result.Ok() {
+			// this should serve!
+			return challenge.VerifyResultOK
+		} else if result == challenge.VerifyResultNone {
+			// we hit timeout
+			return challenge.VerifyResultFail
+		} else {
+			return result
+		}
+	}
+
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("GET "+reg.Path+challenge.VerifyChallengeUrlSuffix, func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/css; charset=utf-8")
+		w.Header().Set("Content-Length", "0")
+
+		data := challenge.RequestDataFromContext(r.Context())
+		key := challenge.GetChallengeKeyForRequest(state, reg, data.Expiration(reg.Duration), r)
+		issuerKey := issuer(key)
+
+		_, _, token, err := challenge.GetVerifyInformation(r, reg)
+		if err != nil {
+			w.WriteHeader(http.StatusBadRequest)
+		}
+
+		verifyResult, _ := verifier(key, []byte(token), r)
+		if !verifyResult.Ok() {
+			w.WriteHeader(http.StatusUnauthorized)
+		} else {
+			w.WriteHeader(http.StatusOK)
+		}
+
+		ob.Solve(issuerKey, verifyResult)
+		if !verifyResult.Ok() {
+			// also give data on other failure when mismatched
+			ob.Solve(token, verifyResult)
+		}
+	})
+	reg.Handler = mux
+
+	return nil
+}