Merge branch 'main' into Xe/osiris

Signed-off-by: Jason Cameron <git@jasoncameron.dev>

.devcontainer/devcontainer.json

@@ -21,7 +21,9 @@
         "golang.go",
         "unifiedjs.vscode-mdx",
         "a-h.templ",
-        "redhat.vscode-yaml"
+        "redhat.vscode-yaml",
+        "hashicorp.hcl",
+        "fredwangwang.vscode-hcl-format"
       ]
     }
   }

.dockerignore

@@ -0,0 +1,25 @@
+.env
+*.deb
+*.rpm
+
+# Additional package locks
+pnpm-lock.yaml
+yarn.lock
+
+# Go binaries and test artifacts
+main
+*.test
+
+node_modules
+
+# MacOS
+.DS_store
+
+# Intellij
+.idea
+
+# how does this get here
+doc/VERSION
+
+web/static/js/*
+!web/static/js/.gitignore

.github/workflows/docker-pr.yml

@@ -2,7 +2,7 @@ name: Docker image builds (pull requests)
 
 on:
   pull_request:
-    branches: [ "main" ]
+    branches: ["main"]
 
 env:
   DOCKER_METADATA_SET_OUTPUT_ENV: "true"
@@ -11,7 +11,32 @@ permissions:
   contents: read
 
 jobs:
-  build:
+  buildx-bake:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          fetch-tags: true
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@b5ca514318bd6ebac0fb2aedd5d36ec1b5c232a2 # v3.10.0
+
+      - name: Build and push
+        id: build
+        uses: docker/bake-action@76f9fa3a758507623da19f6092dc4089a7e61592 # v6.6.0
+        with:
+          source: .
+          push: true
+          sbom: true
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          set: |
+            osiris.tags=ttl.sh/techaro/pr-${{ github.event.number }}/osiris:24h
+
+  containerbuild:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout code

.github/workflows/docker.yml

@@ -17,7 +17,38 @@ permissions:
   pull-requests: write
 
 jobs:
-  build:
+  buildx-bake:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          fetch-tags: true
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@b5ca514318bd6ebac0fb2aedd5d36ec1b5c232a2 # v3.10.0
+
+      - name: Log into registry
+        uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push
+        id: build
+        uses: docker/bake-action@76f9fa3a758507623da19f6092dc4089a7e61592 # v6.6.0
+        with:
+          source: .
+          push: true
+          sbom: true
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          set: ""
+
+  containerbuild:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout code

.vscode/extensions.json

@@ -5,6 +5,8 @@
     "golang.go",
     "unifiedjs.vscode-mdx",
     "a-h.templ",
-    "redhat.vscode-yaml"
+    "redhat.vscode-yaml",
+    "hashicorp.hcl",
+    "fredwangwang.vscode-hcl-format"
   ]
 }

cmd/osiris/internal/config/bind.go

@@ -0,0 +1,39 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"net"
+)
+
+var (
+	ErrInvalidHostpost = errors.New("bind: invalid host:port")
+)
+
+type Bind struct {
+	HTTP    string `hcl:"http"`
+	HTTPS   string `hcl:"https"`
+	Metrics string `hcl:"metrics"`
+}
+
+func (b *Bind) Valid() error {
+	var errs []error
+
+	if _, _, err := net.SplitHostPort(b.HTTP); err != nil {
+		errs = append(errs, fmt.Errorf("%w %q: %w", ErrInvalidHostpost, b.HTTP, err))
+	}
+
+	if _, _, err := net.SplitHostPort(b.HTTPS); err != nil {
+		errs = append(errs, fmt.Errorf("%w %q: %w", ErrInvalidHostpost, b.HTTPS, err))
+	}
+
+	if _, _, err := net.SplitHostPort(b.Metrics); err != nil {
+		errs = append(errs, fmt.Errorf("%w %q: %w", ErrInvalidHostpost, b.Metrics, err))
+	}
+
+	if len(errs) != 0 {
+		return errors.Join(errs...)
+	}
+
+	return nil
+}

cmd/osiris/internal/config/bind_test.go

@@ -0,0 +1,55 @@
+package config
+
+import (
+	"errors"
+	"net"
+	"testing"
+)
+
+func TestBindValid(t *testing.T) {
+	for _, tt := range []struct {
+		name         string
+		precondition func(t *testing.T)
+		bind         Bind
+		err          error
+	}{
+		{
+			name:         "basic",
+			precondition: nil,
+			bind: Bind{
+				HTTP:    ":8081",
+				HTTPS:   ":8082",
+				Metrics: ":8083",
+			},
+			err: nil,
+		},
+		{
+			name: "invalid ports",
+			precondition: func(t *testing.T) {
+				ln, err := net.Listen("tcp", ":8081")
+				if err != nil {
+					t.Fatal(err)
+				}
+				t.Cleanup(func() { ln.Close() })
+			},
+			bind: Bind{
+				HTTP:    "",
+				HTTPS:   "",
+				Metrics: "",
+			},
+			err: ErrInvalidHostpost,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.precondition != nil {
+				tt.precondition(t)
+			}
+
+			if err := tt.bind.Valid(); !errors.Is(err, tt.err) {
+				t.Logf("want: %v", tt.err)
+				t.Logf("got:  %v", err)
+				t.Error("got wrong error from validation function")
+			}
+		})
+	}
+}

cmd/osiris/internal/config/config.go

@@ -0,0 +1,31 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+)
+
+type Toplevel struct {
+	Bind    Bind     `hcl:"bind,block"`
+	Domains []Domain `hcl:"domain,block"`
+}
+
+func (t *Toplevel) Valid() error {
+	var errs []error
+
+	if err := t.Bind.Valid(); err != nil {
+		errs = append(errs, fmt.Errorf("invalid bind block:\n%w", err))
+	}
+
+	for _, d := range t.Domains {
+		if err := d.Valid(); err != nil {
+			errs = append(errs, fmt.Errorf("when parsing domain %s: %w", d.Name, err))
+		}
+	}
+
+	if len(errs) != 0 {
+		return fmt.Errorf("invalid configuration file:\n%w", errors.Join(errs...))
+	}
+
+	return nil
+}

cmd/osiris/internal/config/domain.go

@@ -0,0 +1,66 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+
+	"golang.org/x/net/idna"
+)
+
+var (
+	ErrInvalidDomainName      = errors.New("domain: name is invalid")
+	ErrInvalidDomainTLSConfig = errors.New("domain: TLS config is invalid")
+	ErrInvalidURL             = errors.New("invalid URL")
+	ErrInvalidURLScheme       = errors.New("URL has invalid scheme")
+)
+
+type Domain struct {
+	Name               string `hcl:"name,label"`
+	TLS                TLS    `hcl:"tls,block"`
+	Target             string `hcl:"target"`
+	InsecureSkipVerify bool   `hcl:"insecure_skip_verify,optional"`
+	HealthTarget       string `hcl:"health_target"`
+}
+
+func (d Domain) Valid() error {
+	var errs []error
+
+	if _, err := idna.Lookup.ToASCII(d.Name); err != nil {
+		errs = append(errs, fmt.Errorf("%w %q: %w", ErrInvalidDomainName, d.Name, err))
+	}
+
+	if err := d.TLS.Valid(); err != nil {
+		errs = append(errs, fmt.Errorf("%w: %w", ErrInvalidDomainTLSConfig, err))
+	}
+
+	if err := isURLValid(d.Target); err != nil {
+		errs = append(errs, fmt.Errorf("target has %w %q: %w", ErrInvalidURL, d.Target, err))
+	}
+
+	if err := isURLValid(d.HealthTarget); err != nil {
+		errs = append(errs, fmt.Errorf("health_target has %w %q: %w", ErrInvalidURL, d.HealthTarget, err))
+	}
+
+	if len(errs) != 0 {
+		return errors.Join(errs...)
+	}
+
+	return nil
+}
+
+func isURLValid(input string) error {
+	u, err := url.Parse(input)
+	if err != nil {
+		return err
+	}
+
+	switch u.Scheme {
+	case "http", "https", "h2c", "unix":
+		// do nothing
+	default:
+		return fmt.Errorf("%w %s has scheme %s (want http, https, h2c, unix)", ErrInvalidURLScheme, input, u.Scheme)
+	}
+
+	return nil
+}

cmd/osiris/internal/config/domain_test.go

@@ -0,0 +1,89 @@
+package config
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestDomainValid(t *testing.T) {
+	for _, tt := range []struct {
+		name  string
+		input Domain
+		err   error
+	}{
+		{
+			name: "simple happy path",
+			input: Domain{
+				Name: "anubis.techaro.lol",
+				TLS: TLS{
+					Cert: "./testdata/tls/selfsigned.crt",
+					Key:  "./testdata/tls/selfsigned.key",
+				},
+				Target:       "http://localhost:3000",
+				HealthTarget: "http://localhost:9091/healthz",
+			},
+		},
+		{
+			name: "invalid domain name",
+			input: Domain{
+				Name: "\uFFFD.techaro.lol",
+				TLS: TLS{
+					Cert: "./testdata/tls/selfsigned.crt",
+					Key:  "./testdata/tls/selfsigned.key",
+				},
+				Target:       "http://localhost:3000",
+				HealthTarget: "http://localhost:9091/healthz",
+			},
+			err: ErrInvalidDomainName,
+		},
+		{
+			name: "invalid tls config",
+			input: Domain{
+				Name: "anubis.techaro.lol",
+				TLS: TLS{
+					Cert: "./testdata/tls/invalid.crt",
+					Key:  "./testdata/tls/invalid.key",
+				},
+				Target:       "http://localhost:3000",
+				HealthTarget: "http://localhost:9091/healthz",
+			},
+			err: ErrInvalidDomainTLSConfig,
+		},
+		{
+			name: "invalid URL",
+			input: Domain{
+				Name: "anubis.techaro.lol",
+				TLS: TLS{
+					Cert: "./testdata/tls/selfsigned.crt",
+					Key:  "./testdata/tls/selfsigned.key",
+				},
+				Target:       "file://[::1:3000",
+				HealthTarget: "file://[::1:9091/healthz",
+			},
+			err: ErrInvalidURL,
+		},
+		{
+			name: "wrong URL scheme",
+			input: Domain{
+				Name: "anubis.techaro.lol",
+				TLS: TLS{
+					Cert: "./testdata/tls/selfsigned.crt",
+					Key:  "./testdata/tls/selfsigned.key",
+				},
+				Target:       "file://localhost:3000",
+				HealthTarget: "file://localhost:9091/healthz",
+			},
+			err: ErrInvalidURLScheme,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := tt.input.Valid(); !errors.Is(err, tt.err) {
+				t.Logf("want: %v", tt.err)
+				t.Logf("got:  %v", err)
+				t.Error("got wrong error from validation function")
+			} else {
+				t.Log(err)
+			}
+		})
+	}
+}

cmd/osiris/internal/config/testdata/tls/invalid.crt

@@ -0,0 +1 @@
+aorsentaeiorsntoiearnstoieanrsoietnaioresntoeiar

cmd/osiris/internal/config/testdata/tls/invalid.key

@@ -0,0 +1 @@
+aorsentaeiorsntoiearnstoieanrsoietnaioresntoeiar

cmd/osiris/internal/config/testdata/tls/selfsigned.crt

@@ -0,0 +1,11 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

cmd/osiris/internal/config/testdata/tls/selfsigned.key

@@ -0,0 +1,3 @@
+-----BEGIN PRIVATE KEY-----
+MC4CAQAwBQYDK2VwBCIEIOHKoX22Mha6SnnpLm34fSSfTUDbRiDCi6N1nOgTOlds
+-----END PRIVATE KEY-----

cmd/osiris/internal/config/tls.go

@@ -0,0 +1,40 @@
+package config
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"os"
+)
+
+var (
+	ErrCantReadTLS       = errors.New("tls: can't read TLS")
+	ErrInvalidTLSKeypair = errors.New("tls: can't parse TLS keypair")
+)
+
+type TLS struct {
+	Cert string `hcl:"cert"`
+	Key  string `hcl:"key"`
+}
+
+func (t TLS) Valid() error {
+	var errs []error
+
+	if _, err := os.Stat(t.Cert); err != nil {
+		errs = append(errs, fmt.Errorf("%w certificate %s: %w", ErrCantReadTLS, t.Cert, err))
+	}
+
+	if _, err := os.Stat(t.Key); err != nil {
+		errs = append(errs, fmt.Errorf("%w key %s: %w", ErrCantReadTLS, t.Key, err))
+	}
+
+	if _, err := tls.LoadX509KeyPair(t.Cert, t.Key); err != nil {
+		errs = append(errs, fmt.Errorf("%w (%s, %s): %w", ErrInvalidTLSKeypair, t.Cert, t.Key, err))
+	}
+
+	if len(errs) != 0 {
+		return errors.Join(errs...)
+	}
+
+	return nil
+}

cmd/osiris/internal/config/tls_test.go

@@ -0,0 +1,48 @@
+package config
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestTLSValid(t *testing.T) {
+	for _, tt := range []struct {
+		name  string
+		input TLS
+		err   error
+	}{
+		{
+			name: "simple selfsigned",
+			input: TLS{
+				Cert: "./testdata/tls/selfsigned.crt",
+				Key:  "./testdata/tls/selfsigned.key",
+			},
+		},
+		{
+			name: "files don't exist",
+			input: TLS{
+				Cert: "./testdata/tls/nonexistent.crt",
+				Key:  "./testdata/tls/nonexistent.key",
+			},
+			err: ErrCantReadTLS,
+		},
+		{
+			name: "invalid keypair",
+			input: TLS{
+				Cert: "./testdata/tls/invalid.crt",
+				Key:  "./testdata/tls/invalid.key",
+			},
+			err: ErrInvalidTLSKeypair,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := tt.input.Valid(); !errors.Is(err, tt.err) {
+				t.Logf("want: %v", tt.err)
+				t.Logf("got:  %v", err)
+				t.Error("got wrong error from validation function")
+			} else {
+				t.Log(err)
+			}
+		})
+	}
+}

cmd/osiris/internal/entrypoint/entrypoint.go

@@ -0,0 +1,85 @@
+package entrypoint
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"net"
+
+	"github.com/TecharoHQ/anubis/cmd/osiris/internal/config"
+	"github.com/TecharoHQ/anubis/internal"
+	"github.com/hashicorp/hcl/v2/hclsimple"
+	"golang.org/x/sync/errgroup"
+	healthv1 "google.golang.org/grpc/health/grpc_health_v1"
+)
+
+type Options struct {
+	ConfigFname string
+}
+
+func Main(ctx context.Context, opts Options) error {
+	internal.SetHealth("osiris", healthv1.HealthCheckResponse_NOT_SERVING)
+
+	var cfg config.Toplevel
+	if err := hclsimple.DecodeFile(opts.ConfigFname, nil, &cfg); err != nil {
+		return fmt.Errorf("can't read configuration file %s:\n\n%w", opts.ConfigFname, err)
+	}
+
+	if err := cfg.Valid(); err != nil {
+		return fmt.Errorf("configuration file %s is invalid:\n\n%w", opts.ConfigFname, err)
+	}
+
+	rtr, err := NewRouter(cfg)
+	if err != nil {
+		return err
+	}
+	rtr.opts = opts
+	go rtr.backgroundReloadConfig(ctx)
+
+	g, gCtx := errgroup.WithContext(ctx)
+
+	// HTTP
+	g.Go(func() error {
+		ln, err := net.Listen("tcp", cfg.Bind.HTTP)
+		if err != nil {
+			return fmt.Errorf("(HTTP) can't bind to tcp %s: %w", cfg.Bind.HTTP, err)
+		}
+		defer ln.Close()
+
+		go func(ctx context.Context) {
+			<-ctx.Done()
+			ln.Close()
+		}(ctx)
+
+		slog.Info("listening", "for", "http", "bind", cfg.Bind.HTTP)
+
+		return rtr.HandleHTTP(gCtx, ln)
+	})
+
+	// HTTPS
+	g.Go(func() error {
+		ln, err := net.Listen("tcp", cfg.Bind.HTTPS)
+		if err != nil {
+			return fmt.Errorf("(https) can't bind to tcp %s: %w", cfg.Bind.HTTPS, err)
+		}
+		defer ln.Close()
+
+		go func(ctx context.Context) {
+			<-ctx.Done()
+			ln.Close()
+		}(ctx)
+
+		slog.Info("listening", "for", "https", "bind", cfg.Bind.HTTPS)
+
+		return rtr.HandleHTTPS(gCtx, ln)
+	})
+
+	// Metrics
+	g.Go(func() error {
+		return rtr.ListenAndServeMetrics(gCtx, cfg.Bind.Metrics)
+	})
+
+	internal.SetHealth("osiris", healthv1.HealthCheckResponse_SERVING)
+
+	return g.Wait()
+}

cmd/osiris/internal/entrypoint/entrypoint_test.go

@@ -0,0 +1,93 @@
+package entrypoint
+
+import (
+	"context"
+	"errors"
+	"net"
+	"net/http"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestMainGoodConfig(t *testing.T) {
+	files, err := os.ReadDir("./testdata/good")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, st := range files {
+		t.Run(st.Name(), func(t *testing.T) {
+			ctx, cancel := context.WithCancel(t.Context())
+			cfg := loadConfig(t, filepath.Join("testdata", "good", st.Name()))
+
+			go func(ctx context.Context) {
+				if err := Main(ctx, Options{
+					ConfigFname: filepath.Join("testdata", "good", st.Name()),
+				}); err != nil {
+					var netOpErr *net.OpError
+					switch {
+					case errors.Is(err, context.Canceled):
+						// Context was canceled, this is expected
+						return
+					case errors.As(err, &netOpErr):
+						// Network operation error occurred
+						t.Logf("Network operation error: %v", netOpErr)
+						return
+					case errors.Is(err, http.ErrServerClosed):
+						// Server was closed, this is expected
+						return
+					default:
+						// Other unexpected error
+						panic(err)
+					}
+				}
+			}(ctx)
+
+			wait := 5 * time.Millisecond
+
+			for i := range make([]struct{}, 10) {
+				if i != 0 {
+					time.Sleep(wait)
+					wait = wait * 2
+				}
+
+				t.Logf("try %d (wait=%s)", i+1, wait)
+
+				resp, err := http.Get("http://localhost" + cfg.Bind.Metrics + "/readyz")
+				if err != nil {
+					continue
+				}
+
+				if resp.StatusCode != http.StatusOK {
+					continue
+				}
+
+				cancel()
+				return
+			}
+
+			t.Fatal("router initialization did not work")
+		})
+	}
+}
+
+func TestMainBadConfig(t *testing.T) {
+	files, err := os.ReadDir("./testdata/bad")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, st := range files {
+		t.Run(st.Name(), func(t *testing.T) {
+			if err := Main(t.Context(), Options{
+				ConfigFname: filepath.Join("testdata", "bad", st.Name()),
+			}); err == nil {
+				t.Error("wanted an error but got none")
+			} else {
+				t.Log(err)
+			}
+		})
+	}
+}

cmd/osiris/internal/entrypoint/h2c.go

@@ -0,0 +1,35 @@
+package entrypoint
+
+import (
+	"crypto/tls"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+
+	"golang.org/x/net/http2"
+)
+
+func newH2CReverseProxy(target *url.URL) *httputil.ReverseProxy {
+	target.Scheme = "http"
+
+	director := func(req *http.Request) {
+		req.URL.Scheme = target.Scheme
+		req.URL.Host = target.Host
+		req.Host = target.Host
+	}
+
+	// Use h2c transport
+	transport := &http2.Transport{
+		AllowHTTP: true,
+		DialTLS: func(network, addr string, cfg *tls.Config) (net.Conn, error) {
+			// Just do plain TCP (h2c)
+			return net.Dial(network, addr)
+		},
+	}
+
+	return &httputil.ReverseProxy{
+		Director:  director,
+		Transport: transport,
+	}
+}

cmd/osiris/internal/entrypoint/h2c_test.go

@@ -0,0 +1,51 @@
+package entrypoint
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
+)
+
+func newH2cServer(t *testing.T, h http.Handler) *httptest.Server {
+	t.Helper()
+
+	h2s := &http2.Server{}
+
+	srv := httptest.NewServer(h2c.NewHandler(h, h2s))
+	t.Cleanup(func() {
+		srv.Close()
+	})
+
+	return srv
+}
+
+func TestH2CReverseProxy(t *testing.T) {
+	h := &ackHandler{}
+
+	srv := newH2cServer(t, h)
+
+	u, err := url.Parse(srv.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rp := httptest.NewServer(newH2CReverseProxy(u))
+	defer rp.Close()
+
+	resp, err := rp.Client().Get(rp.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		t.Errorf("wrong status code from reverse proxy: %d", resp.StatusCode)
+	}
+
+	if !h.ack {
+		t.Error("h2c handler was not executed")
+	}
+}

cmd/osiris/internal/entrypoint/metrics.go

@@ -0,0 +1,72 @@
+package entrypoint
+
+import (
+	"bytes"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"sort"
+
+	"github.com/TecharoHQ/anubis/internal"
+	healthv1 "google.golang.org/grpc/health/grpc_health_v1"
+)
+
+func healthz(w http.ResponseWriter, r *http.Request) {
+	services, err := internal.HealthSrv.List(r.Context(), nil)
+	if err != nil {
+		slog.Error("can't get list of services", "err", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	var keys []string
+	for k := range services.Statuses {
+		if k == "" {
+			continue
+		}
+		keys = append(keys, k)
+	}
+
+	sort.Strings(keys)
+
+	var msg bytes.Buffer
+
+	var healthy bool = true
+
+	for _, k := range keys {
+		st := services.Statuses[k].GetStatus()
+		fmt.Fprintf(&msg, "%s: %s\n", k, st)
+		switch st {
+		case healthv1.HealthCheckResponse_SERVING:
+			// do nothing
+		default:
+			healthy = false
+		}
+	}
+
+	if !healthy {
+		w.WriteHeader(http.StatusInternalServerError)
+	}
+
+	w.Write(msg.Bytes())
+}
+
+func readyz(w http.ResponseWriter, r *http.Request) {
+	st, ok := internal.GetHealth("osiris")
+	if !ok {
+		slog.Error("health service osiris does not exist, file a bug")
+		http.Error(w, "health service osiris does not exist", http.StatusExpectationFailed)
+	}
+
+	switch st {
+	case healthv1.HealthCheckResponse_NOT_SERVING:
+		http.Error(w, "NOT OK", http.StatusInternalServerError)
+		return
+	case healthv1.HealthCheckResponse_SERVING:
+		fmt.Fprintln(w, "OK")
+		return
+	default:
+		http.Error(w, "UNKNOWN", http.StatusFailedDependency)
+		return
+	}
+}

cmd/osiris/internal/entrypoint/metrics_test.go

@@ -0,0 +1,66 @@
+package entrypoint
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/TecharoHQ/anubis/internal"
+	healthv1 "google.golang.org/grpc/health/grpc_health_v1"
+)
+
+func TestHealthz(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(healthz))
+
+	internal.SetHealth("osiris", healthv1.HealthCheckResponse_NOT_SERVING)
+
+	resp, err := srv.Client().Get(srv.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode == http.StatusOK {
+		t.Errorf("wanted not ready but got %d", resp.StatusCode)
+	}
+
+	internal.SetHealth("osiris", healthv1.HealthCheckResponse_SERVING)
+
+	resp, err = srv.Client().Get(srv.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Errorf("wanted ready but got %d", resp.StatusCode)
+	}
+}
+
+func TestReadyz(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(readyz))
+
+	internal.SetHealth("osiris", healthv1.HealthCheckResponse_NOT_SERVING)
+
+	resp, err := srv.Client().Get(srv.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode == http.StatusOK {
+		t.Errorf("wanted not ready but got %d", resp.StatusCode)
+	}
+
+	internal.SetHealth("osiris", healthv1.HealthCheckResponse_SERVING)
+
+	resp, err = srv.Client().Get(srv.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Errorf("wanted ready but got %d", resp.StatusCode)
+	}
+}

cmd/osiris/internal/entrypoint/router.go

@@ -0,0 +1,320 @@
+package entrypoint
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"os"
+	"os/signal"
+	"strings"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/TecharoHQ/anubis/cmd/osiris/internal/config"
+	"github.com/TecharoHQ/anubis/internal"
+	"github.com/TecharoHQ/anubis/internal/fingerprint"
+	"github.com/felixge/httpsnoop"
+	"github.com/hashicorp/hcl/v2/hclsimple"
+	"github.com/lum8rjack/go-ja4h"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+var (
+	ErrTargetInvalid     = errors.New("[unexpected] target invalid")
+	ErrNoHandler         = errors.New("[unexpected] no handler for domain")
+	ErrInvalidTLSKeypair = errors.New("[unexpected] invalid TLS keypair")
+	ErrNoCert            = errors.New("this server does not have a certificate for that domain")
+
+	requestsPerDomain = promauto.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: "techaro",
+		Subsystem: "osiris",
+		Name:      "request_count",
+	}, []string{"domain", "method", "response_code"})
+
+	responseTime = promauto.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "techaro",
+		Subsystem: "osiris",
+		Name:      "response_time",
+	}, []string{"domain"})
+
+	unresolvedRequests = promauto.NewGauge(prometheus.GaugeOpts{
+		Namespace: "techaro",
+		Subsystem: "osiris",
+		Name:      "unresolved_requests",
+	})
+)
+
+type Router struct {
+	lock     sync.RWMutex
+	routes   map[string]http.Handler
+	tlsCerts map[string]*tls.Certificate
+	opts     Options
+}
+
+func (rtr *Router) setConfig(c config.Toplevel) error {
+	var errs []error
+	newMap := map[string]http.Handler{}
+	newCerts := map[string]*tls.Certificate{}
+
+	for _, d := range c.Domains {
+		var domainErrs []error
+
+		u, err := url.Parse(d.Target)
+		if err != nil {
+			domainErrs = append(domainErrs, fmt.Errorf("%w %q: %v", ErrTargetInvalid, d.Target, err))
+		}
+
+		var h http.Handler
+
+		if u != nil {
+			switch u.Scheme {
+			case "http", "https":
+				rp := httputil.NewSingleHostReverseProxy(u)
+
+				if d.InsecureSkipVerify {
+					rp.Transport = &http.Transport{
+						TLSClientConfig: &tls.Config{
+							InsecureSkipVerify: true,
+						},
+					}
+				}
+
+				h = rp
+			case "h2c":
+				h = newH2CReverseProxy(u)
+			case "unix":
+				h = &httputil.ReverseProxy{
+					Director: func(r *http.Request) {
+						r.URL.Scheme = "http"
+						r.URL.Host = d.Name
+						r.Host = d.Name
+					},
+					Transport: &http.Transport{
+						DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
+							return net.Dial("unix", strings.TrimPrefix(d.Target, "unix://"))
+						},
+					},
+				}
+			}
+		}
+
+		if h == nil {
+			domainErrs = append(domainErrs, ErrNoHandler)
+		}
+
+		newMap[d.Name] = h
+
+		cert, err := tls.LoadX509KeyPair(d.TLS.Cert, d.TLS.Key)
+		if err != nil {
+			domainErrs = append(domainErrs, fmt.Errorf("%w: %w", ErrInvalidTLSKeypair, err))
+		}
+
+		newCerts[d.Name] = &cert
+
+		if len(domainErrs) != 0 {
+			errs = append(errs, fmt.Errorf("invalid domain %s: %w", d.Name, errors.Join(domainErrs...)))
+		}
+	}
+
+	if len(errs) != 0 {
+		return fmt.Errorf("can't compile config to routing map: %w", errors.Join(errs...))
+	}
+
+	rtr.lock.Lock()
+	rtr.routes = newMap
+	rtr.tlsCerts = newCerts
+	rtr.lock.Unlock()
+
+	return nil
+}
+
+func (rtr *Router) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate, error) {
+	rtr.lock.RLock()
+	cert, ok := rtr.tlsCerts[hello.ServerName]
+	rtr.lock.RUnlock()
+
+	if !ok {
+		return nil, ErrNoCert
+	}
+
+	return cert, nil
+}
+
+func (rtr *Router) loadConfig() error {
+	slog.Info("reloading config", "fname", rtr.opts.ConfigFname)
+	var cfg config.Toplevel
+	if err := hclsimple.DecodeFile(rtr.opts.ConfigFname, nil, &cfg); err != nil {
+		return err
+	}
+
+	if err := cfg.Valid(); err != nil {
+		return err
+	}
+
+	if err := rtr.setConfig(cfg); err != nil {
+		return err
+	}
+
+	slog.Info("done!")
+
+	return nil
+}
+
+func (rtr *Router) backgroundReloadConfig(ctx context.Context) {
+	t := time.NewTicker(time.Hour)
+	defer t.Stop()
+	ch := make(chan os.Signal, 1)
+	signal.Notify(ch, syscall.SIGHUP)
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-t.C:
+			if err := rtr.loadConfig(); err != nil {
+				slog.Error("can't reload config", "fname", rtr.opts.ConfigFname, "err", err)
+			}
+		case <-ch:
+			if err := rtr.loadConfig(); err != nil {
+				slog.Error("can't reload config", "fname", rtr.opts.ConfigFname, "err", err)
+			}
+		}
+	}
+}
+
+func NewRouter(c config.Toplevel) (*Router, error) {
+	result := &Router{
+		routes: map[string]http.Handler{},
+	}
+
+	if err := result.setConfig(c); err != nil {
+		return nil, err
+	}
+
+	return result, nil
+}
+
+func (rtr *Router) HandleHTTP(ctx context.Context, ln net.Listener) error {
+	srv := http.Server{
+		Handler:  rtr,
+		ErrorLog: internal.GetFilteredHTTPLogger(),
+	}
+
+	go func(ctx context.Context) {
+		<-ctx.Done()
+		srv.Close()
+	}(ctx)
+
+	return srv.Serve(ln)
+}
+
+func (rtr *Router) HandleHTTPS(ctx context.Context, ln net.Listener) error {
+	tc := &tls.Config{
+		GetCertificate: rtr.GetCertificate,
+	}
+
+	srv := &http.Server{
+		Handler:   rtr,
+		ErrorLog:  internal.GetFilteredHTTPLogger(),
+		TLSConfig: tc,
+	}
+
+	go func(ctx context.Context) {
+		<-ctx.Done()
+		srv.Close()
+	}(ctx)
+
+	fingerprint.ApplyTLSFingerprinter(srv)
+
+	return srv.ServeTLS(ln, "", "")
+}
+
+func (rtr *Router) ListenAndServeMetrics(ctx context.Context, addr string) error {
+	ln, err := net.Listen("tcp", addr)
+	if err != nil {
+		return fmt.Errorf("(metrics) can't bind to tcp %s: %w", addr, err)
+	}
+	defer ln.Close()
+
+	go func(ctx context.Context) {
+		<-ctx.Done()
+		ln.Close()
+	}(ctx)
+
+	mux := http.NewServeMux()
+
+	mux.Handle("/metrics", promhttp.Handler())
+	mux.HandleFunc("/readyz", readyz)
+	mux.HandleFunc("/healthz", healthz)
+
+	slog.Info("listening", "for", "metrics", "bind", addr)
+
+	srv := http.Server{
+		Addr:     addr,
+		Handler:  mux,
+		ErrorLog: internal.GetFilteredHTTPLogger(),
+	}
+
+	go func(ctx context.Context) {
+		<-ctx.Done()
+		srv.Close()
+	}(ctx)
+
+	return srv.Serve(ln)
+}
+
+func (rtr *Router) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var host = r.Host
+
+	if strings.Contains(host, ":") {
+		host, _, _ = net.SplitHostPort(host)
+	}
+
+	var h http.Handler
+	var ok bool
+
+	ja4hFP := ja4h.JA4H(r)
+
+	slog.Info("got request", "method", r.Method, "host", host, "path", r.URL.Path)
+
+	rtr.lock.RLock()
+	h, ok = rtr.routes[host]
+	rtr.lock.RUnlock()
+
+	if !ok {
+		unresolvedRequests.Inc()
+		http.NotFound(w, r) // TODO(Xe): brand this
+		return
+	}
+
+	r.Header.Set("X-Http-Ja4h-Fingerprint", ja4hFP)
+
+	if fp := fingerprint.GetTLSFingerprint(r); fp != nil {
+		if ja3n := fp.JA3N(); ja3n != nil {
+			r.Header.Set("X-Tls-Ja3n-Fingerprint", ja3n.String())
+		}
+		if ja4 := fp.JA4(); ja4 != nil {
+			r.Header.Set("X-Tls-Ja4-Fingerprint", ja4.String())
+		}
+	}
+
+	if tcpFP := fingerprint.GetTCPFingerprint(r); tcpFP != nil {
+		r.Header.Set("X-Tcp-Ja4t-Fingerprint", tcpFP.String())
+	}
+
+	m := httpsnoop.CaptureMetrics(h, w, r)
+
+	requestsPerDomain.WithLabelValues(host, r.Method, fmt.Sprint(m.Code)).Inc()
+	responseTime.WithLabelValues(host).Observe(float64(m.Duration.Milliseconds()))
+
+	slog.Info("request completed", "host", host, "method", r.Method, "response_code", m.Code, "duration_ms", m.Duration.Milliseconds())
+}

cmd/osiris/internal/entrypoint/router_test.go

@@ -0,0 +1,319 @@
+package entrypoint
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/TecharoHQ/anubis/cmd/osiris/internal/config"
+	"github.com/hashicorp/hcl/v2/hclsimple"
+)
+
+func loadConfig(t *testing.T, fname string) config.Toplevel {
+	t.Helper()
+
+	var cfg config.Toplevel
+	if err := hclsimple.DecodeFile(fname, nil, &cfg); err != nil {
+		t.Fatalf("can't read configuration file %s: %v", fname, err)
+	}
+
+	if err := cfg.Valid(); err != nil {
+		t.Errorf("configuration file %s is invalid: %v", "./testdata/selfsigned.hcl", err)
+	}
+
+	return cfg
+}
+
+func newRouter(t *testing.T, cfg config.Toplevel) *Router {
+	t.Helper()
+
+	rtr, err := NewRouter(cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return rtr
+}
+
+func TestNewRouter(t *testing.T) {
+	cfg := loadConfig(t, "./testdata/good/selfsigned.hcl")
+	rtr := newRouter(t, cfg)
+
+	srv := httptest.NewServer(rtr)
+	defer srv.Close()
+}
+
+func TestNewRouterFails(t *testing.T) {
+	cfg := loadConfig(t, "./testdata/good/selfsigned.hcl")
+
+	cfg.Domains = append(cfg.Domains, config.Domain{
+		Name: "test1.internal",
+		TLS: config.TLS{
+			Cert: "./testdata/tls/invalid.crt",
+			Key:  "./testdata/tls/invalid.key",
+		},
+		Target:       cfg.Domains[0].Target,
+		HealthTarget: cfg.Domains[0].HealthTarget,
+	})
+
+	rtr, err := NewRouter(cfg)
+	if err == nil {
+		t.Fatal("wanted an error but got none")
+	}
+
+	srv := httptest.NewServer(rtr)
+	defer srv.Close()
+}
+
+func TestRouterSetConfig(t *testing.T) {
+	for _, tt := range []struct {
+		name        string
+		configFname string
+		mutation    func(cfg config.Toplevel) config.Toplevel
+		err         error
+	}{
+		{
+			name:        "basic",
+			configFname: "./testdata/good/selfsigned.hcl",
+			mutation: func(cfg config.Toplevel) config.Toplevel {
+				return cfg
+			},
+		},
+		{
+			name:        "all schemes",
+			configFname: "./testdata/good/selfsigned.hcl",
+			mutation: func(cfg config.Toplevel) config.Toplevel {
+				cfg.Domains = append(cfg.Domains, config.Domain{
+					Name:         "http.internal",
+					TLS:          cfg.Domains[0].TLS,
+					Target:       "http://[::1]:3000",
+					HealthTarget: cfg.Domains[0].HealthTarget,
+				})
+				cfg.Domains = append(cfg.Domains, config.Domain{
+					Name:         "https.internal",
+					TLS:          cfg.Domains[0].TLS,
+					Target:       "https://[::1]:3000",
+					HealthTarget: cfg.Domains[0].HealthTarget,
+				})
+				cfg.Domains = append(cfg.Domains, config.Domain{
+					Name:         "h2c.internal",
+					TLS:          cfg.Domains[0].TLS,
+					Target:       "h2c://[::1]:3000",
+					HealthTarget: cfg.Domains[0].HealthTarget,
+				})
+				cfg.Domains = append(cfg.Domains, config.Domain{
+					Name:         "unix.internal",
+					TLS:          cfg.Domains[0].TLS,
+					Target:       "unix://foo.sock",
+					HealthTarget: cfg.Domains[0].HealthTarget,
+				})
+
+				return cfg
+			},
+		},
+		{
+			name:        "invalid TLS",
+			configFname: "./testdata/good/selfsigned.hcl",
+			mutation: func(cfg config.Toplevel) config.Toplevel {
+				cfg.Domains = append(cfg.Domains, config.Domain{
+					Name: "test1.internal",
+					TLS: config.TLS{
+						Cert: "./testdata/tls/invalid.crt",
+						Key:  "./testdata/tls/invalid.key",
+					},
+					Target:       cfg.Domains[0].Target,
+					HealthTarget: cfg.Domains[0].HealthTarget,
+				})
+
+				return cfg
+			},
+			err: ErrInvalidTLSKeypair,
+		},
+		{
+			name:        "target is not a valid URL",
+			configFname: "./testdata/good/selfsigned.hcl",
+			mutation: func(cfg config.Toplevel) config.Toplevel {
+				cfg.Domains = append(cfg.Domains, config.Domain{
+					Name:         "test1.internal",
+					TLS:          cfg.Domains[0].TLS,
+					Target:       "http://[::1:443",
+					HealthTarget: cfg.Domains[0].HealthTarget,
+				})
+
+				return cfg
+			},
+			err: ErrTargetInvalid,
+		},
+		{
+			name:        "invalid target scheme",
+			configFname: "./testdata/good/selfsigned.hcl",
+			mutation: func(cfg config.Toplevel) config.Toplevel {
+				cfg.Domains = append(cfg.Domains, config.Domain{
+					Name:         "test1.internal",
+					TLS:          cfg.Domains[0].TLS,
+					Target:       "foo://",
+					HealthTarget: cfg.Domains[0].HealthTarget,
+				})
+
+				return cfg
+			},
+			err: ErrNoHandler,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := loadConfig(t, tt.configFname)
+			rtr := newRouter(t, cfg)
+
+			cfg = tt.mutation(cfg)
+
+			if err := rtr.setConfig(cfg); !errors.Is(err, tt.err) {
+				t.Logf("want: %v", tt.err)
+				t.Logf("got:  %v", err)
+				t.Error("got wrong error from rtr.setConfig function")
+			}
+		})
+	}
+}
+
+type ackHandler struct {
+	ack bool
+}
+
+func (ah *ackHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	ah.ack = true
+	fmt.Fprintln(w, "OK")
+}
+
+func (ah *ackHandler) Reset() {
+	ah.ack = false
+}
+
+func newUnixServer(t *testing.T, h http.Handler) string {
+	sockName := filepath.Join(t.TempDir(), "s")
+	ln, err := net.Listen("unix", sockName)
+	if err != nil {
+		t.Fatalf("can't listen on %s: %v", sockName, err)
+	}
+	t.Cleanup(func() {
+		ln.Close()
+		os.Remove(sockName)
+	})
+
+	go func(ctx context.Context) {
+		srv := &http.Server{
+			Handler: h,
+		}
+
+		go func() {
+			<-ctx.Done()
+			srv.Close()
+		}()
+
+		srv.Serve(ln)
+	}(t.Context())
+
+	return "unix://" + sockName
+}
+
+func TestRouterGetCertificate(t *testing.T) {
+	cfg := loadConfig(t, "./testdata/good/selfsigned.hcl")
+	rtr := newRouter(t, cfg)
+
+	for _, tt := range []struct {
+		domainName string
+		err        error
+	}{
+		{
+			domainName: "osiris.local.cetacean.club",
+		},
+		{
+			domainName: "whacky-fun.local",
+			err:        ErrNoCert,
+		},
+	} {
+		t.Run(tt.domainName, func(t *testing.T) {
+			if _, err := rtr.GetCertificate(&tls.ClientHelloInfo{ServerName: tt.domainName}); !errors.Is(err, tt.err) {
+				t.Logf("want: %v", tt.err)
+				t.Logf("got:  %v", err)
+				t.Error("got wrong error from rtr.GetCertificate")
+			}
+		})
+	}
+}
+
+func TestRouterServeAllProtocols(t *testing.T) {
+	cfg := loadConfig(t, "./testdata/good/all_protocols.hcl")
+
+	httpAckHandler := &ackHandler{}
+	httpsAckHandler := &ackHandler{}
+	h2cAckHandler := &ackHandler{}
+	unixAckHandler := &ackHandler{}
+
+	httpSrv := httptest.NewServer(httpAckHandler)
+	httpsSrv := httptest.NewTLSServer(httpsAckHandler)
+	h2cSrv := newH2cServer(t, h2cAckHandler)
+	unixPath := newUnixServer(t, unixAckHandler)
+
+	cfg.Domains[0].Target = httpSrv.URL
+	cfg.Domains[1].Target = httpsSrv.URL
+	cfg.Domains[2].Target = strings.ReplaceAll(h2cSrv.URL, "http:", "h2c:")
+	cfg.Domains[3].Target = unixPath
+
+	// enc := json.NewEncoder(os.Stderr)
+	// enc.SetIndent("", "  ")
+	// enc.Encode(cfg)
+
+	rtr := newRouter(t, cfg)
+
+	cli := &http.Client{
+		Transport: &http.Transport{
+			TLSClientConfig: &tls.Config{
+				InsecureSkipVerify: true,
+			},
+		},
+	}
+
+	t.Run("plain http", func(t *testing.T) {
+		ln, err := net.Listen("tcp", ":0")
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(func() {
+			ln.Close()
+		})
+
+		go rtr.HandleHTTP(t.Context(), ln)
+
+		serverURL := "http://" + ln.Addr().String()
+		t.Log(serverURL)
+
+		for _, d := range cfg.Domains {
+			t.Run(d.Name, func(t *testing.T) {
+				req, err := http.NewRequestWithContext(t.Context(), http.MethodGet, serverURL, nil)
+				if err != nil {
+					t.Fatal(err)
+				}
+
+				req.Host = d.Name
+
+				resp, err := cli.Do(req)
+				if err != nil {
+					t.Fatal(err)
+				}
+				defer resp.Body.Close()
+
+				if resp.StatusCode != http.StatusOK {
+					t.Fatalf("wrong status code %d", resp.StatusCode)
+				}
+			})
+		}
+	})
+}

cmd/osiris/internal/entrypoint/testdata/bad/invalid.hcl

@@ -0,0 +1,15 @@
+bind {
+  http    = ":65530"
+  https   = ":65531"
+  metrics = ":65532"
+}
+
+domain "osiris.local.cetacean.club" {
+  tls {
+    cert = "./testdata/invalid.crt"
+    key  = "./testdata/invalid.key"
+  }
+
+  target        = "http://localhost:3000"
+  health_target = "http://localhost:9091/healthz"
+}

cmd/osiris/internal/entrypoint/testdata/good/all_protocols.hcl

@@ -0,0 +1,46 @@
+bind {
+  http    = ":65520"
+  https   = ":65521"
+  metrics = ":65522"
+}
+
+domain "http.internal" {
+  tls {
+    cert = "./testdata/selfsigned.crt"
+    key  = "./testdata/selfsigned.key"
+  }
+
+  target        = "http://localhost:65510" # XXX(Xe) this is overwritten
+  health_target = "http://localhost:9091/healthz"
+}
+
+domain "https.internal" {
+  tls {
+    cert = "./testdata/selfsigned.crt"
+    key  = "./testdata/selfsigned.key"
+  }
+
+  target               = "https://localhost:65511" # XXX(Xe) this is overwritten
+  insecure_skip_verify = true
+  health_target        = "http://localhost:9091/healthz"
+}
+
+domain "h2c.internal" {
+  tls {
+    cert = "./testdata/selfsigned.crt"
+    key  = "./testdata/selfsigned.key"
+  }
+
+  target        = "h2c://localhost:65511" # XXX(Xe) this is overwritten
+  health_target = "http://localhost:9091/healthz"
+}
+
+domain "unix.internal" {
+  tls {
+    cert = "./testdata/selfsigned.crt"
+    key  = "./testdata/selfsigned.key"
+  }
+
+  target        = "http://localhost:65511" # XXX(Xe) this is overwritten
+  health_target = "http://localhost:9091/healthz"
+}

cmd/osiris/internal/entrypoint/testdata/good/selfsigned.hcl

@@ -0,0 +1,15 @@
+bind {
+  http    = ":65530"
+  https   = ":65531"
+  metrics = ":65532"
+}
+
+domain "osiris.local.cetacean.club" {
+  tls {
+    cert = "./testdata/selfsigned.crt"
+    key  = "./testdata/selfsigned.key"
+  }
+
+  target        = "http://localhost:3000"
+  health_target = "http://localhost:9091/healthz"
+}

cmd/osiris/internal/entrypoint/testdata/selfsigned.crt

@@ -0,0 +1,11 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

cmd/osiris/internal/entrypoint/testdata/selfsigned.key

@@ -0,0 +1,3 @@
+-----BEGIN PRIVATE KEY-----
+MC4CAQAwBQYDK2VwBCIEIBop42tiZ0yzhaKo9NAc0PlAyBsE8NAE0i9Z7s2lgZuR
+-----END PRIVATE KEY-----

cmd/osiris/main.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/TecharoHQ/anubis"
+	"github.com/TecharoHQ/anubis/cmd/osiris/internal/entrypoint"
+	"github.com/TecharoHQ/anubis/internal"
+	"github.com/facebookgo/flagenv"
+)
+
+var (
+	configFname = flag.String("config", "./osiris.hcl", "Configuration file (HCL), see docs")
+	slogLevel   = flag.String("slog-level", "INFO", "logging level (see https://pkg.go.dev/log/slog#hdr-Levels)")
+	versionFlag = flag.Bool("version", false, "if true, show version information then quit")
+)
+
+func main() {
+	flagenv.Parse()
+	flag.Parse()
+
+	if *versionFlag {
+		fmt.Println("Osiris", anubis.Version)
+		return
+	}
+
+	internal.InitSlog(*slogLevel)
+
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer cancel()
+
+	if err := entrypoint.Main(ctx, entrypoint.Options{
+		ConfigFname: *configFname,
+	}); err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
+	}
+}

cmd/osiris/osiris.hcl

@@ -0,0 +1,15 @@
+bind {
+  http    = ":3004"
+  https   = ":3005"
+  metrics = ":9091"
+}
+
+domain "osiris.local.cetacean.club" {
+  tls {
+    cert = "./internal/config/testdata/tls/selfsigned.crt"
+    key  = "./internal/config/testdata/tls/selfsigned.key"
+  }
+
+  target        = "http://localhost:3000"
+  health_target = "http://localhost:9091/healthz"
+}

docker-bake.hcl

@@ -0,0 +1,32 @@
+variable "ALPINE_VERSION" { default = "3.22" }
+variable "GITHUB_SHA" { default = "devel" }
+variable "VERSION" { default = "devel-docker" }
+
+group "default" {
+  targets = [
+    "osiris",
+  ]
+}
+
+target "osiris" {
+  args = {
+    ALPINE_VERSION = "3.22"
+    VERSION        = "${VERSION}"
+  }
+  context    = "."
+  dockerfile = "./docker/osiris.Dockerfile"
+  platforms = [
+    "linux/amd64",
+    "linux/arm64",
+    "linux/arm/v7",
+    "linux/ppc64le",
+    "linux/riscv64",
+  ]
+  pull       = true
+  sbom       = true
+  provenance = true
+  tags = [
+    "ghcr.io/techarohq/anubis/osiris:${VERSION}",
+    "ghcr.io/techarohq/anubis/osiris:main"
+  ]
+}

docker/osiris.Dockerfile

@@ -0,0 +1,30 @@
+ARG ALPINE_VERSION=edge
+FROM --platform=${BUILDPLATFORM} alpine:${ALPINE_VERSION} AS build
+
+RUN apk -U add go nodejs git build-base git npm bash zstd brotli gzip
+
+WORKDIR /app
+
+COPY go.mod go.sum ./
+RUN --mount=type=cache,target=/root/.cache --mount=type=cache,target=/root/go go mod download
+
+COPY package.json package-lock.json ./
+RUN npm ci
+
+ARG TARGETOS
+ARG TARGETARCH
+ARG VERSION=devel-docker
+
+COPY . .
+RUN --mount=type=cache,target=/root/.cache --mount=type=cache,target=/root/go GOOS=${TARGETOS} GOARCH=${TARGETARCH} CGO_ENABLED=0 GOARM=7 go build -gcflags "all=-N -l" -o /app/bin/osiris -ldflags "-s -w -extldflags -static -X github.com/TecharoHQ/anubis.Version=${VERSION}" ./cmd/osiris
+
+FROM alpine:${ALPINE_VERSION} AS run
+WORKDIR /app
+
+RUN apk -U add ca-certificates mailcap
+
+COPY --from=build /app/bin/osiris /app/bin/osiris
+
+CMD ["/app/bin/osiris"]
+
+LABEL org.opencontainers.image.source="https://github.com/TecharoHQ/anubis"

go.mod

@@ -47,8 +47,10 @@ require (
 	github.com/Songmu/gitconfig v0.2.0 // indirect
 	github.com/TecharoHQ/yeet v0.6.0 // indirect
 	github.com/a-h/parse v0.0.0-20250122154542-74294addb73e // indirect
+	github.com/agext/levenshtein v1.2.1 // indirect
 	github.com/andybalholm/brotli v1.1.0 // indirect
 	github.com/antlr4-go/antlr/v4 v4.13.0 // indirect
+	github.com/apparentlymart/go-textseg/v15 v15.0.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/blakesmith/ar v0.0.0-20190502131153-809d4375e1fb // indirect
 	github.com/cavaliergopher/cpio v1.0.1 // indirect
@@ -93,6 +95,7 @@ require (
 	github.com/goccy/go-yaml v1.12.0 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/groupcache v0.0.0-20241129210726-2c02b8208cf8 // indirect
+	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/google/go-github/v70 v70.0.0 // indirect
 	github.com/google/go-querystring v1.1.0 // indirect
 	github.com/google/pprof v0.0.0-20230207041349-798e818bf904 // indirect
@@ -101,6 +104,7 @@ require (
 	github.com/goreleaser/fileglob v1.3.0 // indirect
 	github.com/goreleaser/nfpm/v2 v2.42.1 // indirect
 	github.com/hashicorp/go-version v1.7.0 // indirect
+	github.com/hashicorp/hcl/v2 v2.24.0 // indirect
 	github.com/huandu/xstrings v1.5.0 // indirect
 	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
 	github.com/kevinburke/ssh_config v1.2.0 // indirect
@@ -111,6 +115,7 @@ require (
 	github.com/mattn/go-colorable v0.1.14 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/go-wordwrap v1.0.1 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	github.com/moby/docker-image-spec v1.3.1 // indirect
 	github.com/moby/go-archive v0.1.0 // indirect
@@ -150,6 +155,7 @@ require (
 	github.com/xanzy/ssh-agent v0.3.3 // indirect
 	github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 // indirect
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
+	github.com/zclconf/go-cty v1.16.3 // indirect
 	gitlab.com/digitalxero/go-conventional-commit v1.0.7 // indirect
 	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect

go.sum

@@ -40,6 +40,8 @@ github.com/TecharoHQ/yeet v0.6.0 h1:RCBAjr7wIlllsgy0tpvWpLX7jsZgu2tiuBY3RrprcR0=
 github.com/TecharoHQ/yeet v0.6.0/go.mod h1:bj2V4Fg8qKQXoiuPZa3HuawrE8g+LsOQv/9q2WyGSsA=
 github.com/a-h/parse v0.0.0-20250122154542-74294addb73e h1:HjVbSQHy+dnlS6C3XajZ69NYAb5jbGNfHanvm1+iYlo=
 github.com/a-h/parse v0.0.0-20250122154542-74294addb73e/go.mod h1:3mnrkvGpurZ4ZrTDbYU84xhwXW2TjTKShSwjRi2ihfQ=
+github.com/agext/levenshtein v1.2.1 h1:QmvMAjj2aEICytGiWzmxoE0x2KZvE0fvmqMOfy2tjT8=
+github.com/agext/levenshtein v1.2.1/go.mod h1:JEDfjyjHDjOF/1e4FlBE/PkbqA9OfWu2ki2W0IB5558=
 github.com/a-h/templ v0.3.920 h1:IQjjTu4KGrYreHo/ewzSeS8uefecisPayIIc9VflLSE=
 github.com/a-h/templ v0.3.920/go.mod h1:FFAu4dI//ESmEN7PQkJ7E7QfnSEMdcnu7QrAY8Dn334=
 github.com/andybalholm/brotli v1.1.0 h1:eLKJA0d02Lf0mVpIDgYnqXcUn0GqVmEFny3VuID1U3M=
@@ -48,6 +50,8 @@ github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be h1:9AeTilPcZAjCFI
 github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be/go.mod h1:ySMOLuWl6zY27l47sB3qLNK6tF2fkHG55UZxx8oIVo4=
 github.com/antlr4-go/antlr/v4 v4.13.0 h1:lxCg3LAv+EUK6t1i0y1V6/SLeUi0eKEKdhQAlS8TVTI=
 github.com/antlr4-go/antlr/v4 v4.13.0/go.mod h1:pfChB/xh/Unjila75QW7+VU4TSnWnnk9UTnmpPaOR2g=
+github.com/apparentlymart/go-textseg/v15 v15.0.0 h1:uYvfpb3DyLSCGWnctWKGj857c6ew1u1fNQOlOtuGxQY=
+github.com/apparentlymart/go-textseg/v15 v15.0.0/go.mod h1:K8XmNZdhEBkdlyDdvbmmsvpAG721bKi0joRfFdHIWJ4=
 github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5 h1:0CwZNZbxp69SHPdPJAN/hZIm0C4OItdklCFmMRWYpio=
 github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
@@ -225,6 +229,8 @@ github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.3/go.mod h1:ndYquD05frm2vACXE1ns
 github.com/h2non/parth v0.0.0-20190131123155-b4df798d6542/go.mod h1:Ow0tF8D4Kplbc8s8sSb3V2oUCygFHVp8gC3Dn6U4MNI=
 github.com/hashicorp/go-version v1.7.0 h1:5tqGy27NaOTB8yJKUZELlFAS/LTKJkrmONwQKeRZfjY=
 github.com/hashicorp/go-version v1.7.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09ZGVZPK5anwXA=
+github.com/hashicorp/hcl/v2 v2.24.0 h1:2QJdZ454DSsYGoaE6QheQZjtKZSUs9Nh2izTWiwQxvE=
+github.com/hashicorp/hcl/v2 v2.24.0/go.mod h1:oGoO1FIQYfn/AgyOhlg9qLC6/nOJPX3qGbkZpYAcqfM=
 github.com/henvic/httpretty v0.0.6/go.mod h1:X38wLjWXHkXT7r2+uK8LjCMne9rsuNaBLJ+5cU2/Pmo=
 github.com/huandu/xstrings v1.5.0 h1:2ag3IFq9ZDANvthTwTiqSSZLjDc+BedvHPAp5tJy2TI=
 github.com/huandu/xstrings v1.5.0/go.mod h1:y5/lhBue+AyNmUVz9RLU9xbLR0o4KIIExikq4ovT0aE=
@@ -278,6 +284,8 @@ github.com/mitchellh/copystructure v1.2.0 h1:vpKXTN4ewci03Vljg/q9QvCGUDttBOGBIa1
 github.com/mitchellh/copystructure v1.2.0/go.mod h1:qLl+cE2AmVv+CoeAwDPye/v+N2HKCj9FbZEVFJRxO9s=
 github.com/mitchellh/go-ps v1.0.0 h1:i6ampVEEF4wQFF+bkYfwYgY+F/uYJDktmvLPf7qIgjc=
 github.com/mitchellh/go-ps v1.0.0/go.mod h1:J4lOc8z8yJs6vUwklHw2XEIiT4z4C40KtWVN3nvg8Pg=
+github.com/mitchellh/go-wordwrap v1.0.1 h1:TLuKupo69TCn6TQSyGxwI1EblZZEsQ0vMlAFQflz0v0=
+github.com/mitchellh/go-wordwrap v1.0.1/go.mod h1:R62XHJLzvMFRBbcrT7m7WgmE1eOyTSsCt+hzestvNj0=
 github.com/mitchellh/reflectwalk v1.0.2 h1:G2LzWKi524PWgd3mLHV8Y5k7s6XUvT0Gef6zxSIeXaQ=
 github.com/mitchellh/reflectwalk v1.0.2/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
 github.com/moby/docker-image-spec v1.3.1 h1:jMKff3w6PgbfSa69GfNg+zN/XLhfXJGnEx3Nl2EsFP0=
@@ -403,6 +411,8 @@ github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9dec
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 github.com/yusufpapurcu/wmi v1.2.4 h1:zFUKzehAFReQwLys1b/iSMl+JQGSCSjtVqQn9bBrPo0=
 github.com/yusufpapurcu/wmi v1.2.4/go.mod h1:SBZ9tNy3G9/m5Oi98Zks0QjeHVDvuK0qfxQmPyzfmi0=
+github.com/zclconf/go-cty v1.16.3 h1:osr++gw2T61A8KVYHoQiFbFd1Lh3JOCXc/jFLJXKTxk=
+github.com/zclconf/go-cty v1.16.3/go.mod h1:VvMs5i0vgZdhYawQNq5kePSpLAoz8u1xvZgrPIxfnZE=
 gitlab.com/digitalxero/go-conventional-commit v1.0.7 h1:8/dO6WWG+98PMhlZowt/YjuiKhqhGlOCwlIV8SqqGh8=
 gitlab.com/digitalxero/go-conventional-commit v1.0.7/go.mod h1:05Xc2BFsSyC5tKhK0y+P3bs0AwUtNuTp+mTpbCU/DZ0=
 go.etcd.io/bbolt v1.4.2 h1:IrUHp260R8c+zYx/Tm8QZr04CX+qWS5PGfPdevhdm1I=

internal/fingerprint/ja3n.go

@@ -0,0 +1,97 @@
+package fingerprint
+
+import (
+	"crypto/md5"
+	"crypto/tls"
+	"encoding/hex"
+	"slices"
+	"strconv"
+)
+
+// TLSFingerprintJA3N represents a JA3N fingerprint
+type TLSFingerprintJA3N [md5.Size]byte
+
+func (f TLSFingerprintJA3N) String() string {
+	return hex.EncodeToString(f[:])
+}
+
+func buildJA3N(hello *tls.ClientHelloInfo, sortExtensions bool) TLSFingerprintJA3N {
+	buf := make([]byte, 0, 256)
+
+	{
+		var sslVersion uint16
+		var hasGrease bool
+		for _, v := range hello.SupportedVersions {
+			if v&greaseMask != greaseValue {
+				if v > sslVersion {
+					sslVersion = v
+				}
+			} else {
+				hasGrease = true
+			}
+		}
+
+		// maximum TLS 1.2 as specified on JA3, as TLS 1.3 is put in SupportedVersions
+		if slices.Contains(hello.Extensions, extensionSupportedVersions) && hasGrease && sslVersion > tls.VersionTLS12 {
+			sslVersion = tls.VersionTLS12
+		}
+
+		buf = strconv.AppendUint(buf, uint64(sslVersion), 10)
+		buf = append(buf, ',')
+	}
+
+	n := 0
+	for _, cipher := range hello.CipherSuites {
+		//if !slices.Contains(greaseValues[:], cipher) {
+		if cipher&greaseMask != greaseValue {
+			buf = strconv.AppendUint(buf, uint64(cipher), 10)
+			buf = append(buf, '-')
+			n = 1
+		}
+	}
+
+	buf = buf[:len(buf)-n]
+	buf = append(buf, ',')
+	n = 0
+
+	extensions := hello.Extensions
+	if sortExtensions {
+		extensions = slices.Clone(extensions)
+		slices.Sort(extensions)
+	}
+
+	for _, extension := range extensions {
+		if extension&greaseMask != greaseValue {
+			buf = strconv.AppendUint(buf, uint64(extension), 10)
+			buf = append(buf, '-')
+			n = 1
+		}
+	}
+
+	buf = buf[:len(buf)-n]
+	buf = append(buf, ',')
+	n = 0
+
+	for _, curve := range hello.SupportedCurves {
+		if curve&greaseMask != greaseValue {
+			buf = strconv.AppendUint(buf, uint64(curve), 10)
+			buf = append(buf, '-')
+			n = 1
+		}
+	}
+
+	buf = buf[:len(buf)-n]
+	buf = append(buf, ',')
+	n = 0
+
+	for _, point := range hello.SupportedPoints {
+		buf = strconv.AppendUint(buf, uint64(point), 10)
+		buf = append(buf, '-')
+		n = 1
+	}
+
+	buf = buf[:len(buf)-n]
+
+	sum := md5.Sum(buf)
+	return TLSFingerprintJA3N(sum[:])
+}

internal/fingerprint/ja4.go

@@ -0,0 +1,176 @@
+package fingerprint
+
+import (
+	"crypto/sha256"
+	"crypto/tls"
+	"encoding/hex"
+	"fmt"
+	"slices"
+	"strconv"
+	"strings"
+)
+
+// TLSFingerprintJA4 represents a JA4 fingerprint
+type TLSFingerprintJA4 struct {
+	A [10]byte
+	B [6]byte
+	C [6]byte
+}
+
+func (f *TLSFingerprintJA4) String() string {
+	if f == nil {
+		return ""
+	}
+
+	return strings.Join([]string{
+		string(f.A[:]),
+		hex.EncodeToString(f.B[:]),
+		hex.EncodeToString(f.C[:]),
+	}, "_")
+}
+
+func buildJA4(hello *tls.ClientHelloInfo) (ja4 TLSFingerprintJA4) {
+	buf := make([]byte, 0, 36)
+
+	hasQuic := false
+
+	for _, ext := range hello.Extensions {
+		if ext == extensionQUICTransportParameters {
+			hasQuic = true
+		}
+	}
+
+	switch hasQuic {
+	case true:
+		buf = append(buf, 'q')
+	case false:
+		buf = append(buf, 't')
+	}
+
+	{
+		var sslVersion uint16
+		for _, v := range hello.SupportedVersions {
+			if v&greaseMask != greaseValue {
+				if v > sslVersion {
+					sslVersion = v
+				}
+			}
+		}
+
+		switch sslVersion {
+		case tls.VersionTLS10:
+			buf = append(buf, '1', '0')
+		case tls.VersionTLS11:
+			buf = append(buf, '1', '1')
+		case tls.VersionTLS12:
+			buf = append(buf, '1', '2')
+		case tls.VersionTLS13:
+			buf = append(buf, '1', '3')
+		default:
+			sslVersion -= 0x0201
+			buf = strconv.AppendUint(buf, uint64(sslVersion>>8), 10)
+			buf = strconv.AppendUint(buf, uint64(sslVersion&0xff), 10)
+		}
+
+	}
+
+	if slices.Contains(hello.Extensions, extensionServerName) && hello.ServerName != "" {
+		buf = append(buf, 'd')
+	} else {
+		buf = append(buf, 'i')
+	}
+
+	ciphers := make([]uint16, 0, len(hello.CipherSuites))
+	for _, cipher := range hello.CipherSuites {
+		if cipher&greaseMask != greaseValue {
+			ciphers = append(ciphers, cipher)
+		}
+	}
+
+	extensionCount := 0
+	extensions := make([]uint16, 0, len(hello.Extensions))
+	for _, extension := range hello.Extensions {
+		if extension&greaseMask != greaseValue {
+			extensionCount++
+			if extension != extensionALPN && extension != extensionServerName {
+				extensions = append(extensions, extension)
+			}
+		}
+	}
+
+	schemes := make([]tls.SignatureScheme, 0, len(hello.SignatureSchemes))
+
+	for _, scheme := range hello.SignatureSchemes {
+		if scheme&greaseMask != greaseValue {
+			schemes = append(schemes, scheme)
+		}
+	}
+
+	//TODO: maybe little endian
+	slices.Sort(ciphers)
+	slices.Sort(extensions)
+	//slices.Sort(schemes)
+
+	if len(ciphers) < 10 {
+		buf = append(buf, '0')
+		buf = strconv.AppendUint(buf, uint64(len(ciphers)), 10)
+	} else if len(ciphers) > 99 {
+		buf = append(buf, '9', '9')
+	} else {
+		buf = strconv.AppendUint(buf, uint64(len(ciphers)), 10)
+	}
+
+	if extensionCount < 10 {
+		buf = append(buf, '0')
+		buf = strconv.AppendUint(buf, uint64(extensionCount), 10)
+	} else if extensionCount > 99 {
+		buf = append(buf, '9', '9')
+	} else {
+		buf = strconv.AppendUint(buf, uint64(extensionCount), 10)
+	}
+
+	if len(hello.SupportedProtos) > 0 && len(hello.SupportedProtos[0]) > 1 {
+		buf = append(buf, hello.SupportedProtos[0][0], hello.SupportedProtos[0][len(hello.SupportedProtos[0])-1])
+	} else {
+		buf = append(buf, '0', '0')
+	}
+
+	copy(ja4.A[:], buf)
+
+	ja4.B = ja4SHA256(uint16SliceToHex(ciphers))
+
+	extBuf := uint16SliceToHex(extensions)
+
+	if len(schemes) > 0 {
+		extBuf = append(extBuf, '_')
+		extBuf = append(extBuf, uint16SliceToHex(schemes)...)
+	}
+
+	ja4.C = ja4SHA256(extBuf)
+
+	return ja4
+}
+
+func uint16SliceToHex[T ~uint16](in []T) (out []byte) {
+	if len(in) == 0 {
+		return out
+	}
+	out = slices.Grow(out, hex.EncodedLen(len(in)*2)+len(in))
+
+	for _, n := range in {
+		out = append(out, fmt.Sprintf("%04x", uint16(n))...)
+		out = append(out, ',')
+	}
+	out = out[:len(out)-1]
+
+	return out
+}
+
+func ja4SHA256(buf []byte) [6]byte {
+	if len(buf) == 0 {
+		return [6]byte{0, 0, 0, 0, 0, 0}
+	}
+	sum := sha256.Sum256(buf)
+
+	return [6]byte(sum[:6])
+}

internal/fingerprint/tcp.go

@@ -0,0 +1,46 @@
+package fingerprint
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+// JA4T represents a TCP fingerprint
+type JA4T struct {
+	Window      uint32
+	Options     []uint8
+	MSS         uint16
+	WindowScale uint8
+}
+
+func (j JA4T) String() string {
+	var sb strings.Builder
+
+	// Start with the window size
+	fmt.Fprintf(&sb, "%d", j.Window)
+
+	// Append each option
+	for i, opt := range j.Options {
+		if i == 0 {
+			fmt.Fprint(&sb, "_")
+		} else {
+			fmt.Fprint(&sb, "-")
+		}
+		fmt.Fprintf(&sb, "%d", opt)
+	}
+
+	// Append MSS and WindowScale
+	fmt.Fprintf(&sb, "_%d_%d", j.MSS, j.WindowScale)
+
+	return sb.String()
+}
+
+// GetTCPFingerprint extracts TCP fingerprint from HTTP request context
+func GetTCPFingerprint(r *http.Request) *JA4T {
+	ptr := r.Context().Value(tcpFingerprintKey{})
+	if fpPtr, ok := ptr.(*JA4T); ok && ptr != nil && fpPtr != nil {
+		return fpPtr
+	}
+	return nil
+}

internal/fingerprint/tcp_freebsd.go

@@ -0,0 +1,106 @@
+//go:build freebsd
+
+package fingerprint
+
+import (
+	"fmt"
+	"net"
+	"syscall"
+	"unsafe"
+)
+
+type tcpInfo struct {
+	State          uint8
+	Options        uint8
+	SndScale       uint8
+	RcvScale       uint8
+	__pad          [4]byte
+	Rto            uint32
+	Ato            uint32
+	SndMss         uint32
+	RcvMss         uint32
+	Unacked        uint32
+	Sacked         uint32
+	Lost           uint32
+	Retrans        uint32
+	Fackets        uint32
+	Last_data_sent uint32
+	Last_ack_sent  uint32
+	Last_data_recv uint32
+	Last_ack_recv  uint32
+	Pmtu           uint32
+	Rcv_ssthresh   uint32
+	RTT            uint32
+	RTTvar         uint32
+	Snd_ssthresh   uint32
+	Snd_cwnd       uint32
+	Advmss         uint32
+	Reordering     uint32
+	Rcv_rtt        uint32
+	Rcv_space      uint32
+	Total_retrans  uint32
+	Snd_wnd        uint32
+	// Truncated for brevity — add more fields if needed
+}
+
+// AssignTCPFingerprint extracts TCP fingerprint information from a connection
+func AssignTCPFingerprint(conn net.Conn) (*JA4T, error) {
+	tcpConn, ok := conn.(*net.TCPConn)
+	if !ok {
+		return nil, fmt.Errorf("not a TCPConn")
+	}
+
+	rawConn, err := tcpConn.SyscallConn()
+	if err != nil {
+		return nil, fmt.Errorf("SyscallConn failed: %w", err)
+	}
+
+	var info tcpInfo
+	var sysErr error
+
+	err = rawConn.Control(func(fd uintptr) {
+		size := uint32(unsafe.Sizeof(info))
+		_, _, errno := syscall.Syscall6(
+			syscall.SYS_GETSOCKOPT,
+			fd,
+			uintptr(syscall.IPPROTO_TCP),
+			uintptr(syscall.TCP_INFO),
+			uintptr(unsafe.Pointer(&info)),
+			uintptr(unsafe.Pointer(&size)),
+			0,
+		)
+		if errno != 0 {
+			sysErr = errno
+		}
+	})
+	if err != nil {
+		return nil, fmt.Errorf("SyscallConn.Control: %w", err)
+	}
+	if sysErr != nil {
+		return nil, fmt.Errorf("getsockopt TCP_INFO: %w", sysErr)
+	}
+
+	fp := &JA4T{
+		Window:      info.Snd_wnd,
+		MSS:         uint16(info.SndMss),
+		WindowScale: info.SndScale,
+	}
+
+	const (
+		TCPI_OPT_TIMESTAMPS = 1 << 0
+		TCPI_OPT_SACK       = 1 << 1
+		TCPI_OPT_WSCALE     = 1 << 2
+	)
+
+	if info.Options&TCPI_OPT_SACK != 0 {
+		fp.Options = append(fp.Options, 4, 1)
+	}
+	if info.Options&TCPI_OPT_TIMESTAMPS != 0 {
+		fp.Options = append(fp.Options, 8, 1)
+	}
+	if info.Options&TCPI_OPT_WSCALE != 0 {
+		fp.Options = append(fp.Options, 3)
+	}
+
+	return fp, nil
+}

internal/fingerprint/tcp_linux.go

@@ -0,0 +1,132 @@
+//go:build linux
+
+package fingerprint
+
+import (
+	"fmt"
+	"net"
+	"syscall"
+	"unsafe"
+)
+
+type tcpInfo struct {
+	State                     uint8
+	Ca_state                  uint8
+	Retransmits               uint8
+	Probes                    uint8
+	Backoff                   uint8
+	Options                   uint8
+	Wnd_scale                 uint8
+	Delivery_rate_app_limited uint8
+
+	Rto    uint32
+	Ato    uint32
+	SndMss uint32
+	RcvMss uint32
+
+	Unacked uint32
+	Sacked  uint32
+	Lost    uint32
+	Retrans uint32
+	Fackets uint32
+
+	Last_data_sent  uint32
+	Last_ack_sent   uint32
+	Last_data_recv  uint32
+	Last_ack_recv   uint32
+	PMTU            uint32
+	Rcv_ssthresh    uint32
+	RTT             uint32
+	RTTvar          uint32
+	Snd_ssthresh    uint32
+	Snd_cwnd        uint32
+	Advmss          uint32
+	Reordering      uint32
+	Rcv_rtt         uint32
+	Rcv_space       uint32
+	Total_retrans   uint32
+	Pacing_rate     uint64
+	Max_pacing_rate uint64
+	Bytes_acked     uint64
+	Bytes_received  uint64
+	Segs_out        uint32
+	Segs_in         uint32
+	Notsent_bytes   uint32
+	Min_rtt         uint32
+	Data_segs_in    uint32
+	Data_segs_out   uint32
+	Delivery_rate   uint64
+	Busy_time       uint64
+	Rwnd_limited    uint64
+	Sndbuf_limited  uint64
+	Delivered       uint32
+	Delivered_ce    uint32
+	Bytes_sent      uint64
+	Bytes_retrans   uint64
+	DSACK_dups      uint32
+	Reord_seen      uint32
+	Rcv_ooopack     uint32
+	Snd_wnd         uint32
+}
+
+// AssignTCPFingerprint extracts TCP fingerprint information from a connection
+func AssignTCPFingerprint(conn net.Conn) (*JA4T, error) {
+	tcpConn, ok := conn.(*net.TCPConn)
+	if !ok {
+		return nil, fmt.Errorf("not a TCPConn")
+	}
+
+	rawConn, err := tcpConn.SyscallConn()
+	if err != nil {
+		return nil, fmt.Errorf("SyscallConn failed: %w", err)
+	}
+
+	var info tcpInfo
+	var sysErr error
+
+	err = rawConn.Control(func(fd uintptr) {
+		size := uint32(unsafe.Sizeof(info))
+		_, _, errno := syscall.Syscall6(
+			syscall.SYS_GETSOCKOPT,
+			fd,
+			uintptr(syscall.IPPROTO_TCP),
+			uintptr(syscall.TCP_INFO),
+			uintptr(unsafe.Pointer(&info)),
+			uintptr(unsafe.Pointer(&size)),
+			0,
+		)
+		if errno != 0 {
+			sysErr = errno
+		}
+	})
+	if err != nil {
+		return nil, fmt.Errorf("SyscallConn.Control: %w", err)
+	}
+	if sysErr != nil {
+		return nil, fmt.Errorf("getsockopt TCP_INFO: %w", sysErr)
+	}
+
+	fp := &JA4T{
+		Window: info.Snd_wnd,
+		MSS:    uint16(info.SndMss),
+	}
+
+	const (
+		TCPI_OPT_TIMESTAMPS = 1 << 0
+		TCPI_OPT_SACK       = 1 << 1
+		TCPI_OPT_WSCALE     = 1 << 2
+	)
+
+	if info.Options&TCPI_OPT_SACK != 0 {
+		fp.Options = append(fp.Options, 4, 1)
+	}
+	if info.Options&TCPI_OPT_TIMESTAMPS != 0 {
+		fp.Options = append(fp.Options, 8, 1)
+	}
+	if info.Options&TCPI_OPT_WSCALE != 0 {
+		fp.Options = append(fp.Options, 3)
+		fp.WindowScale = info.Wnd_scale
+	}
+
+	return fp, nil
+}

internal/fingerprint/tcp_unsupported.go

@@ -0,0 +1,11 @@
+//go:build !linux && !freebsd
+
+package fingerprint
+
+import "net"
+
+// AssignTCPFingerprint is not supported on this platform
+func AssignTCPFingerprint(conn net.Conn) (*JA4T, error) {
+	// Not supported on macOS and other platforms
+	return &JA4T{}, nil
+}

internal/fingerprint/tls.go

@@ -0,0 +1,110 @@
+package fingerprint
+
+import (
+	"context"
+	"crypto/tls"
+	"log/slog"
+	"net"
+	"net/http"
+	"sync/atomic"
+)
+
+// ApplyTLSFingerprinter configures a TLS server to capture TLS fingerprints
+func ApplyTLSFingerprinter(server *http.Server) {
+	if server.TLSConfig == nil {
+		return
+	}
+	server.TLSConfig = server.TLSConfig.Clone()
+
+	getConfigForClient := server.TLSConfig.GetConfigForClient
+
+	if getConfigForClient == nil {
+		getConfigForClient = func(info *tls.ClientHelloInfo) (*tls.Config, error) {
+			return nil, nil
+		}
+	}
+
+	server.TLSConfig.GetConfigForClient = func(clientHello *tls.ClientHelloInfo) (*tls.Config, error) {
+		ja3n, ja4 := buildTLSFingerprint(clientHello)
+		ptr := clientHello.Context().Value(tlsFingerprintKey{})
+		if fpPtr, ok := ptr.(*TLSFingerprint); ok && ptr != nil && fpPtr != nil {
+			fpPtr.ja3n.Store(&ja3n)
+			fpPtr.ja4.Store(&ja4)
+		}
+		return getConfigForClient(clientHello)
+	}
+	server.ConnContext = func(ctx context.Context, c net.Conn) context.Context {
+		ctx = context.WithValue(ctx, tlsFingerprintKey{}, &TLSFingerprint{})
+
+		if tc, ok := c.(*tls.Conn); ok {
+			tcpFP, err := AssignTCPFingerprint(tc.NetConn())
+			if err == nil {
+				ctx = context.WithValue(ctx, tcpFingerprintKey{}, tcpFP)
+			} else {
+				slog.Debug("ja4t error", "err", err)
+			}
+		}
+
+		return ctx
+	}
+}
+
+type tcpFingerprintKey struct{}
+type tlsFingerprintKey struct{}
+
+// TLSFingerprint represents TLS fingerprint data
+type TLSFingerprint struct {
+	ja3n atomic.Pointer[TLSFingerprintJA3N]
+	ja4  atomic.Pointer[TLSFingerprintJA4]
+}
+
+// JA3N returns the JA3N fingerprint
+func (f *TLSFingerprint) JA3N() *TLSFingerprintJA3N {
+	return f.ja3n.Load()
+}
+
+// JA4 returns the JA4 fingerprint
+func (f *TLSFingerprint) JA4() *TLSFingerprintJA4 {
+	return f.ja4.Load()
+}
+
+const greaseMask = 0x0F0F
+const greaseValue = 0x0a0a
+
+// TLS extension numbers
+const (
+	extensionServerName              uint16 = 0
+	extensionStatusRequest           uint16 = 5
+	extensionSupportedCurves         uint16 = 10 // supported_groups in TLS 1.3, see RFC 8446, Section 4.2.7
+	extensionSupportedPoints         uint16 = 11
+	extensionSignatureAlgorithms     uint16 = 13
+	extensionALPN                    uint16 = 16
+	extensionSCT                     uint16 = 18
+	extensionExtendedMasterSecret    uint16 = 23
+	extensionSessionTicket           uint16 = 35
+	extensionPreSharedKey            uint16 = 41
+	extensionEarlyData               uint16 = 42
+	extensionSupportedVersions       uint16 = 43
+	extensionCookie                  uint16 = 44
+	extensionPSKModes                uint16 = 45
+	extensionCertificateAuthorities  uint16 = 47
+	extensionSignatureAlgorithmsCert uint16 = 50
+	extensionKeyShare                uint16 = 51
+	extensionQUICTransportParameters uint16 = 57
+	extensionRenegotiationInfo       uint16 = 0xff01
+	extensionECHOuterExtensions      uint16 = 0xfd00
+	extensionEncryptedClientHello    uint16 = 0xfe0d
+)
+
+func buildTLSFingerprint(hello *tls.ClientHelloInfo) (TLSFingerprintJA3N, TLSFingerprintJA4) {
+	return TLSFingerprintJA3N(buildJA3N(hello, true)), buildJA4(hello)
+}
+
+// GetTLSFingerprint extracts TLS fingerprint from HTTP request context
+func GetTLSFingerprint(r *http.Request) *TLSFingerprint {
+	ptr := r.Context().Value(tlsFingerprintKey{})
+	if fpPtr, ok := ptr.(*TLSFingerprint); ok && ptr != nil && fpPtr != nil {
+		return fpPtr
+	}
+	return nil
+}