Merge remote-tracking branch 'origin/stable' into v2

Refactor TLS fragmenting

.github/workflows/ci.yaml

@@ -119,6 +119,39 @@ jobs:
       - name: Run linter
         run: mise tasks run lint
 
+  artifacts:
+    name: Build release artifacts
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - uses: jdx/mise-action@v3
+        name: Install mise
+
+      - name: Cache Go modules
+        uses: actions/cache@v5
+        with:
+          path: ~/go/pkg/mod
+          key: ${{ runner.os }}-gomod-${{ hashFiles('go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-gomod-
+
+      - name: Cache cross-compilation build
+        uses: actions/cache@v5
+        with:
+          path: ~/.cache/go-build
+          key: ${{ runner.os }}-goreleaser-${{ hashFiles('go.sum') }}-${{ hashFiles('**/*.go') }}
+          restore-keys: |
+            ${{ runner.os }}-goreleaser-${{ hashFiles('go.sum') }}-
+            ${{ runner.os }}-goreleaser-
+
+      - name: Run release
+        run: mise tasks run release
+
   docker:
     name: Docker
     runs-on: ubuntu-latest

.github/workflows/codeql-analysis.yml

@@ -45,11 +45,13 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@v6
+      with:
+        submodules: recursive
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v1
+      uses: github/codeql-action/init@v4
       with:
         languages: ${{ matrix.language }}
         # If you wish to specify custom queries, you can do so here or in a config file.
@@ -60,7 +62,7 @@ jobs:
     # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
     # If this step fails, then you should remove it and run the build manually (see below)
     - name: Autobuild
-      uses: github/codeql-action/autobuild@v1
+      uses: github/codeql-action/autobuild@v4
 
     # ℹ️ Command-line programs to run using the OS shell.
     # 📚 https://git.io/JvXDl
@@ -74,4 +76,4 @@ jobs:
     #   make release
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v1
+      uses: github/codeql-action/analyze@v4

.mise.toml

@@ -16,6 +16,12 @@ sources = ["**/*.go", "go.mod", "go.sum"]
 outputs = ["mtg"]
 run = "go build"
 
+[tasks."build:prof"]
+description = "Build binary with profiling enabled"
+sources = ["**/*.go", "go.mod", "go.sum"]
+outputs = ["mtg"]
+run = "go build -tags prof"
+
 [tasks.update]
 description = "Update dependencies"
 run = [

Dockerfile

@@ -33,7 +33,7 @@ RUN go mod download
 COPY . /app
 
 RUN set -x \
-  && version="$(git describe --exact-match HEAD 2>/dev/null || git describe --tags --always)" \
+  && version="$(git describe --exact-match HEAD 2>/dev/null || git describe --tags --always 2>/dev/null || echo dev)" \
   && go build \
       -trimpath \
       -mod=readonly \

README.md

@@ -29,6 +29,8 @@ are the most notable:
 * [Official](https://github.com/TelegramMessenger/MTProxy)
 * [Python](https://github.com/alexbers/mtprotoproxy)
 * [Erlang](https://github.com/seriyps/mtproto_proxy)
+* [Teleproxy (C)](https://github.com/teleproxy/teleproxy)
+* [mtproto.zig (Zig)](https://github.com/sleep3r/mtproto.zig)
 * [Telemt (Rust)](https://github.com/telemt/telemt)
 
 You can use any of these. They work great and all implementations have
@@ -91,6 +93,9 @@ that probably matter.
   software. I also believe that in the case of throwout proxies, this
   the feature is a useless luxury.
 
+  This is very controversial topic. Please read [rationale (in russian)](https://github.com/9seconds/mtg/issues/376#issuecomment-4118726699)
+  and use [mtg-multi](https://github.com/dolonet/mtg-multi) fork if you are disagree with.
+
 * **No adtag support**
 
   Please read [Version 2](#version-2) chapter.

antireplay/stable_bloom_filter_test.go

@@ -12,7 +12,7 @@ type StableBloomFilterTestSuite struct {
 }
 
 func (suite *StableBloomFilterTestSuite) TestOp() {
-	filter := antireplay.NewStableBloomFilter(500, 0.001)
+	filter := antireplay.NewStableBloomFilter(100000, 0.001)
 
 	suite.False(filter.SeenBefore([]byte{1, 2, 3}))
 	suite.False(filter.SeenBefore([]byte{4, 5, 6}))

events/event_stream.go

@@ -38,7 +38,7 @@ func (e EventStream) Send(ctx context.Context, evt mtglib.Event) {
 	select {
 	case <-ctx.Done():
 	case <-e.ctx.Done():
-	case e.chans[int(chanNo)%len(e.chans)] <- evt:
+	case e.chans[chanNo%uint32(len(e.chans))] <- evt:
 	}
 }
 

example.config.toml

@@ -48,6 +48,13 @@ concurrency = 8192
 #     Only ipv4 connectivity is used
 prefer-ip = "prefer-ipv6"
 
+# Public IP addresses of this server. Used by 'mtg access' to generate
+# proxy links and by 'mtg doctor' to validate SNI-DNS match.
+# If not set, mtg tries to detect them automatically via ifconfig.co.
+# Set these if ifconfig.co is unreachable from your server.
+# public-ipv4 = "1.2.3.4"
+# public-ipv6 = "2001:db8::1"
+
 # If this setting is set, then mtg will try to get proxy updates from Telegram
 # Usually this is completely fine to have it disabled, because mtg has a list
 # of some core proxies hardcoded.

go.mod

@@ -15,7 +15,7 @@ require (
 	github.com/prometheus/client_golang v1.23.2
 	github.com/prometheus/common v0.67.5 // indirect
 	github.com/prometheus/procfs v0.20.1 // indirect
-	github.com/rs/zerolog v1.34.0
+	github.com/rs/zerolog v1.35.0
 	github.com/smira/go-statsd v1.3.4
 	github.com/stretchr/objx v0.5.2 // indirect
 	github.com/stretchr/testify v1.11.1
@@ -29,7 +29,7 @@ require (
 require (
 	github.com/beevik/ntp v1.5.0
 	github.com/ncruces/go-dns v1.3.2
-	github.com/pelletier/go-toml/v2 v2.2.4
+	github.com/pelletier/go-toml/v2 v2.3.0
 	github.com/pires/go-proxyproto v0.11.0
 	github.com/things-go/go-socks5 v0.1.0
 	github.com/txthinking/socks5 v0.0.0-20251011041537-5c31f201a10e

go.sum

@@ -18,14 +18,12 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
-github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/d4l3k/messagediff v1.2.1 h1:ZcAIMYsUg0EAp9X+tt8/enBE/Q8Yd5kzPynLyKptt9U=
 github.com/d4l3k/messagediff v1.2.1/go.mod h1:Oozbb1TVXFac9FtSIxHBMnBCq2qeH/2KkEQxENCrlLo=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
@@ -40,11 +38,8 @@ github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
-github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
 github.com/mattn/go-colorable v0.1.14 h1:9A9LHSqF/7dyVVX6g0U9cwm9pG3kP9gSzcuIPHPsaIE=
 github.com/mattn/go-colorable v0.1.14/go.mod h1:6LmQG8QLFO4G5z1gPvYEzlUgJ2wF+stgPZH1UqBm1s8=
-github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
-github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mccutchen/go-httpbin v1.1.1 h1:aEws49HEJEyXHLDnshQVswfUlCVoS8g6h9YaDyaW7RE=
@@ -59,11 +54,10 @@ github.com/panjf2000/ants/v2 v2.12.0 h1:u9JhESo83i/GkZnhfTNuFMMWcNt7mnV1bGJ6FT4w
 github.com/panjf2000/ants/v2 v2.12.0/go.mod h1:tSQuaNQ6r6NRhPt+IZVUevvDyFMTs+eS4ztZc52uJTY=
 github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
 github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
-github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
-github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
+github.com/pelletier/go-toml/v2 v2.3.0 h1:k59bC/lIZREW0/iVaQR8nDHxVq8OVlIzYCOJf421CaM=
+github.com/pelletier/go-toml/v2 v2.3.0/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
 github.com/pires/go-proxyproto v0.11.0 h1:gUQpS85X/VJMdUsYyEgyn59uLJvGqPhJV5YvG68wXH4=
 github.com/pires/go-proxyproto v0.11.0/go.mod h1:ZKAAyp3cgy5Y5Mo4n9AlScrkCZwUy0g3Jf+slqQVcuU=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v1.23.2 h1:Je96obch5RDVy3FDMndoUsjAhG5Edi49h0RJWRi/o0o=
@@ -76,9 +70,8 @@ github.com/prometheus/procfs v0.20.1 h1:XwbrGOIplXW/AU3YhIhLODXMJYyC1isLFfYCsTEy
 github.com/prometheus/procfs v0.20.1/go.mod h1:o9EMBZGRyvDrSPH1RqdxhojkuXstoe4UlK79eF5TGGo=
 github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
 github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
-github.com/rs/xid v1.6.0/go.mod h1:7XoLgs4eV+QndskICGsho+ADou8ySMSjJKDIan90Nz0=
-github.com/rs/zerolog v1.34.0 h1:k43nTLIwcTVQAncfCw4KZ2VY6ukYoZaBPNOE8txlOeY=
-github.com/rs/zerolog v1.34.0/go.mod h1:bJsvje4Z08ROH4Nhs5iH600c3IkWhwp44iRc54W6wYQ=
+github.com/rs/zerolog v1.35.0 h1:VD0ykx7HMiMJytqINBsKcbLS+BJ4WYjz+05us+LRTdI=
+github.com/rs/zerolog v1.35.0/go.mod h1:EjML9kdfa/RMA7h/6z6pYmq1ykOuA8/mjWaEvGI+jcw=
 github.com/smira/go-statsd v1.3.4 h1:kBYWcLSGT+qC6JVbvfz48kX7mQys32fjDOPrfmsSx2c=
 github.com/smira/go-statsd v1.3.4/go.mod h1:RjdsESPgDODtg1VpVVf9MJrEW2Hw0wtRNbmB1CAhu6A=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -133,10 +126,8 @@ golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
 golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=

internal/cli/access.go

@@ -58,6 +58,9 @@ func (a *Access) Run(cli *CLI, version string) error {
 
 	wg.Go(func() {
 		ip := a.PublicIPv4
+		if ip == nil {
+			ip = conf.PublicIPv4.Get(nil)
+		}
 		if ip == nil {
 			ip = getIP(ntw, "tcp4")
 		}
@@ -70,6 +73,9 @@ func (a *Access) Run(cli *CLI, version string) error {
 	})
 	wg.Go(func() {
 		ip := a.PublicIPv6
+		if ip == nil {
+			ip = conf.PublicIPv6.Get(nil)
+		}
 		if ip == nil {
 			ip = getIP(ntw, "tcp6")
 		}

internal/cli/doctor.go

@@ -332,13 +332,20 @@ func (d *Doctor) checkSecretHost(resolver *net.Resolver, ntw mtglib.Network) boo
 		return false
 	}
 
-	ourIP4 := getIP(ntw, "tcp4")
-	ourIP6 := getIP(ntw, "tcp6")
+	ourIP4 := d.conf.PublicIPv4.Get(nil)
+	if ourIP4 == nil {
+		ourIP4 = getIP(ntw, "tcp4")
+	}
+
+	ourIP6 := d.conf.PublicIPv6.Get(nil)
+	if ourIP6 == nil {
+		ourIP6 = getIP(ntw, "tcp6")
+	}
 
 	if ourIP4 == nil && ourIP6 == nil {
 		tplError.Execute(os.Stdout, map[string]any{ //nolint: errcheck
 			"description": "cannot detect public IP address",
-			"error":       errors.New("ifconfig.co is unreachable for both IPv4 and IPv6"),
+			"error":       errors.New("cannot detect automatically and public-ipv4/public-ipv6 are not set in config"),
 		})
 		return false
 	}

internal/cli/run_proxy.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"time"
 
 	"github.com/9seconds/mtg/v2/antireplay"
 	"github.com/9seconds/mtg/v2/events"
@@ -262,6 +263,7 @@ func runProxy(conf *config.Config, version string) error { //nolint: funlen
 
 		AllowFallbackOnUnknownDC: conf.AllowFallbackOnUnknownDC.Get(false),
 		TolerateTimeSkewness:     conf.TolerateTimeSkewness.Value,
+		IdleTimeout:              conf.Network.Timeout.Idle.Get(time.Minute),
 
 		DoppelGangerURLs:    doppelGangerURLs,
 		DoppelGangerPerRaid: conf.Defense.Doppelganger.Repeats.Get(mtglib.DoppelGangerPerRaid),

internal/config/config.go

@@ -35,6 +35,8 @@ type Config struct {
 	DomainFrontingProxyProtocol TypeBool        `json:"domainFrontingProxyProtocol"`
 	TolerateTimeSkewness        TypeDuration    `json:"tolerateTimeSkewness"`
 	Concurrency                 TypeConcurrency `json:"concurrency"`
+	PublicIPv4                  TypeIP          `json:"publicIpv4"`
+	PublicIPv6                  TypeIP          `json:"publicIpv6"`
 	DomainFronting              struct {
 		IP            TypeIP   `json:"ip"`
 		Port          TypePort `json:"port"`

internal/config/config_test.go

@@ -42,6 +42,32 @@ func (suite *ConfigTestSuite) TestParseMinimalConfig() {
 	suite.Equal("0.0.0.0:3128", conf.BindTo.String())
 }
 
+func (suite *ConfigTestSuite) TestParsePublicIP() {
+	conf, err := config.Parse(suite.ReadConfig("public_ip.toml"))
+	suite.NoError(err)
+	suite.Equal("203.0.113.1", conf.PublicIPv4.Get(nil).String())
+	suite.Equal("2001:db8::1", conf.PublicIPv6.Get(nil).String())
+}
+
+func (suite *ConfigTestSuite) TestParsePublicIPv4Only() {
+	conf, err := config.Parse(suite.ReadConfig("public_ip_v4_only.toml"))
+	suite.NoError(err)
+	suite.Equal("203.0.113.1", conf.PublicIPv4.Get(nil).String())
+	suite.Nil(conf.PublicIPv6.Get(nil))
+}
+
+func (suite *ConfigTestSuite) TestParsePublicIPInvalid() {
+	_, err := config.Parse(suite.ReadConfig("public_ip_invalid.toml"))
+	suite.Error(err)
+}
+
+func (suite *ConfigTestSuite) TestParsePublicIPNotSet() {
+	conf, err := config.Parse(suite.ReadConfig("minimal.toml"))
+	suite.NoError(err)
+	suite.Nil(conf.PublicIPv4.Get(nil))
+	suite.Nil(conf.PublicIPv6.Get(nil))
+}
+
 func (suite *ConfigTestSuite) TestString() {
 	conf, err := config.Parse(suite.ReadConfig("minimal.toml"))
 	suite.NoError(err)

internal/config/parse.go

@@ -21,6 +21,8 @@ type tomlConfig struct {
 	DomainFrontingProxyProtocol bool   `toml:"domain-fronting-proxy-protocol" json:"domainFrontingProxyProtocol,omitempty"`
 	TolerateTimeSkewness        string `toml:"tolerate-time-skewness" json:"tolerateTimeSkewness,omitempty"`
 	Concurrency                 uint   `toml:"concurrency" json:"concurrency,omitempty"`
+	PublicIPv4                  string `toml:"public-ipv4" json:"publicIpv4,omitempty"`
+	PublicIPv6                  string `toml:"public-ipv6" json:"publicIpv6,omitempty"`
 	DomainFronting              struct {
 		IP            string `toml:"ip" json:"ip,omitempty"`
 		Port          uint   `toml:"port" json:"port,omitempty"`

internal/config/testdata/public_ip.toml

@@ -0,0 +1,4 @@
+secret = "7oe1GqLy6TBc38CV3jx7q09nb29nbGUuY29t"
+bind-to = "0.0.0.0:3128"
+public-ipv4 = "203.0.113.1"
+public-ipv6 = "2001:db8::1"

internal/config/testdata/public_ip_invalid.toml

@@ -0,0 +1,3 @@
+secret = "7oe1GqLy6TBc38CV3jx7q09nb29nbGUuY29t"
+bind-to = "0.0.0.0:3128"
+public-ipv4 = "not-an-ip"

internal/config/testdata/public_ip_v4_only.toml

@@ -0,0 +1,3 @@
+secret = "7oe1GqLy6TBc38CV3jx7q09nb29nbGUuY29t"
+bind-to = "0.0.0.0:3128"
+public-ipv4 = "203.0.113.1"

mise.lock

@@ -82,40 +82,40 @@ checksum = "sha256:4932cfca5e75bf60fe1c576edf459e5e809e6644664a068185d64b84af3fa
 url = "https://github.com/golangci/golangci-lint/releases/download/v2.11.4/golangci-lint-2.11.4-windows-amd64.zip"
 
 [[tools.goreleaser]]
-version = "2.14.3"
+version = "2.15.2"
 backend = "aqua:goreleaser/goreleaser"
 
 [tools.goreleaser."platforms.linux-arm64"]
-checksum = "sha256:581a10e53c1176b3e81ee45cf531e02dbf899db0bc7b795669347df4276ce948"
-url = "https://github.com/goreleaser/goreleaser/releases/download/v2.14.3/goreleaser_Linux_arm64.tar.gz"
+checksum = "sha256:5db66761a98f6693161e49e1a95d28d2673a892ba60cb4a5e16736cafd41c4c9"
+url = "https://github.com/goreleaser/goreleaser/releases/download/v2.15.2/goreleaser_Linux_arm64.tar.gz"
 provenance = "cosign"
 
 [tools.goreleaser."platforms.linux-arm64-musl"]
-checksum = "sha256:581a10e53c1176b3e81ee45cf531e02dbf899db0bc7b795669347df4276ce948"
-url = "https://github.com/goreleaser/goreleaser/releases/download/v2.14.3/goreleaser_Linux_arm64.tar.gz"
+checksum = "sha256:5db66761a98f6693161e49e1a95d28d2673a892ba60cb4a5e16736cafd41c4c9"
+url = "https://github.com/goreleaser/goreleaser/releases/download/v2.15.2/goreleaser_Linux_arm64.tar.gz"
 provenance = "cosign"
 
 [tools.goreleaser."platforms.linux-x64"]
-checksum = "sha256:dc7faeeeb6da8bdfda788626263a4ae725892a8c7504b975c3234127d4a44579"
-url = "https://github.com/goreleaser/goreleaser/releases/download/v2.14.3/goreleaser_Linux_x86_64.tar.gz"
+checksum = "sha256:0ebdbf0353aba566b969dde746cc4e4806f96c27aa2f3971b229a9df7611fedc"
+url = "https://github.com/goreleaser/goreleaser/releases/download/v2.15.2/goreleaser_Linux_x86_64.tar.gz"
 provenance = "cosign"
 
 [tools.goreleaser."platforms.linux-x64-musl"]
-checksum = "sha256:dc7faeeeb6da8bdfda788626263a4ae725892a8c7504b975c3234127d4a44579"
-url = "https://github.com/goreleaser/goreleaser/releases/download/v2.14.3/goreleaser_Linux_x86_64.tar.gz"
+checksum = "sha256:0ebdbf0353aba566b969dde746cc4e4806f96c27aa2f3971b229a9df7611fedc"
+url = "https://github.com/goreleaser/goreleaser/releases/download/v2.15.2/goreleaser_Linux_x86_64.tar.gz"
 provenance = "cosign"
 
 [tools.goreleaser."platforms.macos-arm64"]
-checksum = "sha256:3507798489e107a78aff36b169de48148a335ac26eb3161608d905f3f3a957bd"
-url = "https://github.com/goreleaser/goreleaser/releases/download/v2.14.3/goreleaser_Darwin_all.tar.gz"
-provenance = "cosign"
+checksum = "sha256:0e6bd67688ac949780bf1166813a91f89856898ef4c40d7d46c2c74ebaa4b9ee"
+url = "https://github.com/goreleaser/goreleaser/releases/download/v2.15.2/goreleaser_Darwin_all.tar.gz"
+provenance = "github-attestations"
 
 [tools.goreleaser."platforms.macos-x64"]
-checksum = "sha256:3507798489e107a78aff36b169de48148a335ac26eb3161608d905f3f3a957bd"
-url = "https://github.com/goreleaser/goreleaser/releases/download/v2.14.3/goreleaser_Darwin_all.tar.gz"
+checksum = "sha256:0e6bd67688ac949780bf1166813a91f89856898ef4c40d7d46c2c74ebaa4b9ee"
+url = "https://github.com/goreleaser/goreleaser/releases/download/v2.15.2/goreleaser_Darwin_all.tar.gz"
 provenance = "cosign"
 
 [tools.goreleaser."platforms.windows-x64"]
-checksum = "sha256:3deea8ff471aa258a2d99f3e5302971d7028647ae8ddaf103257a8113e485a31"
-url = "https://github.com/goreleaser/goreleaser/releases/download/v2.14.3/goreleaser_Windows_x86_64.zip"
+checksum = "sha256:7459832946dbe122c144f8d7f87484d8572ca005b779310aa6bb03346e8de17a"
+url = "https://github.com/goreleaser/goreleaser/releases/download/v2.15.2/goreleaser_Windows_x86_64.zip"
 provenance = "cosign"

mtglib/conns.go

@@ -3,9 +3,12 @@ package mtglib
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"net"
+	"sync/atomic"
+	"time"
 
 	"github.com/9seconds/mtg/v2/essentials"
 	"github.com/pires/go-proxyproto"
@@ -95,3 +98,64 @@ func newConnProxyProtocol(source, target essentials.Conn) *connProxyProtocol {
 		sourceAddr: source.RemoteAddr(),
 	}
 }
+
+// idleTracker is a shared idle tracker for a pair of relay connections.
+// Both directions update the same timestamp so that activity in one direction
+// prevents the other (idle) direction from timing out.
+type idleTracker struct {
+	lastActive atomic.Pointer[time.Time]
+	timeout    time.Duration
+}
+
+func newIdleTracker(timeout time.Duration) *idleTracker {
+	t := &idleTracker{timeout: timeout}
+	t.touch()
+
+	return t
+}
+
+func (t *idleTracker) touch() {
+	stamp := time.Now()
+	t.lastActive.Store(&stamp)
+}
+
+func (t *idleTracker) isIdle() bool {
+	return time.Since(*t.lastActive.Load()) >= t.timeout
+}
+
+type connIdleTimeout struct {
+	essentials.Conn
+
+	tracker *idleTracker
+}
+
+func (c connIdleTimeout) Read(b []byte) (int, error) {
+	var netErr net.Error
+
+	for {
+		c.SetReadDeadline(time.Now().Add(c.tracker.timeout)) //nolint: errcheck
+
+		n, err := c.Conn.Read(b)
+
+		switch {
+		case err == nil:
+			c.tracker.touch()
+			return n, nil
+		case errors.As(err, &netErr) && netErr.Timeout() && !c.tracker.isIdle():
+			continue
+		}
+
+		return n, err
+	}
+}
+
+func (c connIdleTimeout) Write(b []byte) (int, error) {
+	c.SetWriteDeadline(time.Now().Add(c.tracker.timeout)) //nolint: errcheck
+
+	n, err := c.Conn.Write(b)
+	if n > 0 {
+		c.tracker.touch()
+	}
+
+	return n, err //nolint: wrapcheck
+}

mtglib/conns_internal_test.go

@@ -16,6 +16,12 @@ import (
 	"github.com/stretchr/testify/suite"
 )
 
+type netTimeoutError struct{}
+
+func (e netTimeoutError) Error() string   { return "i/o timeout" }
+func (e netTimeoutError) Timeout() bool   { return true }
+func (e netTimeoutError) Temporary() bool { return true }
+
 type ConnRewindBaseConn struct {
 	testlib.EssentialsConnMock
 
@@ -291,6 +297,141 @@ func (suite *ConnProxyProtocolTestSuite) TearDownTest() {
 	suite.targetConnMock.AssertExpectations(suite.T())
 }
 
+type IdleTrackerTestSuite struct {
+	suite.Suite
+}
+
+func (suite *IdleTrackerTestSuite) TestNewNotIdle() {
+	tracker := newIdleTracker(time.Second)
+	suite.False(tracker.isIdle())
+}
+
+func (suite *IdleTrackerTestSuite) TestIdleAfterTimeout() {
+	tracker := newIdleTracker(10 * time.Millisecond)
+	time.Sleep(20 * time.Millisecond)
+
+	suite.True(tracker.isIdle())
+}
+
+func (suite *IdleTrackerTestSuite) TestTouchResetsIdle() {
+	tracker := newIdleTracker(50 * time.Millisecond)
+	time.Sleep(30 * time.Millisecond)
+
+	tracker.touch()
+
+	suite.False(tracker.isIdle())
+}
+
+type ConnIdleTimeoutTestSuite struct {
+	suite.Suite
+
+	connMock *testlib.EssentialsConnMock
+	tracker  *idleTracker
+	conn     connIdleTimeout
+}
+
+func (suite *ConnIdleTimeoutTestSuite) SetupTest() {
+	suite.connMock = &testlib.EssentialsConnMock{}
+	suite.tracker = newIdleTracker(time.Second)
+	suite.conn = connIdleTimeout{
+		Conn:    suite.connMock,
+		tracker: suite.tracker,
+	}
+}
+
+func (suite *ConnIdleTimeoutTestSuite) TearDownTest() {
+	suite.connMock.AssertExpectations(suite.T())
+}
+
+func (suite *ConnIdleTimeoutTestSuite) TestReadOk() {
+	suite.connMock.On("SetReadDeadline", mock.Anything).Return(nil)
+	suite.connMock.On("Read", mock.Anything).Once().Return(5, nil)
+
+	n, err := suite.conn.Read(make([]byte, 10))
+	suite.NoError(err)
+	suite.Equal(5, n)
+}
+
+func (suite *ConnIdleTimeoutTestSuite) TestReadNonTimeoutErr() {
+	suite.connMock.On("SetReadDeadline", mock.Anything).Return(nil)
+	suite.connMock.On("Read", mock.Anything).Once().Return(0, io.EOF)
+
+	n, err := suite.conn.Read(make([]byte, 10))
+	suite.True(errors.Is(err, io.EOF))
+	suite.Equal(0, n)
+}
+
+func (suite *ConnIdleTimeoutTestSuite) TestReadTimeoutRetriesWhenNotIdle() {
+	suite.connMock.On("SetReadDeadline", mock.Anything).Return(nil)
+	suite.connMock.On("Read", mock.Anything).Once().Return(0, netTimeoutError{})
+	suite.connMock.On("Read", mock.Anything).Once().Return(5, nil)
+
+	n, err := suite.conn.Read(make([]byte, 10))
+	suite.NoError(err)
+	suite.Equal(5, n)
+}
+
+func (suite *ConnIdleTimeoutTestSuite) TestReadTimeoutClosesWhenIdle() {
+	suite.tracker = newIdleTracker(time.Millisecond)
+	suite.conn = connIdleTimeout{
+		Conn:    suite.connMock,
+		tracker: suite.tracker,
+	}
+
+	time.Sleep(5 * time.Millisecond)
+
+	suite.connMock.On("SetReadDeadline", mock.Anything).Return(nil)
+	suite.connMock.On("Read", mock.Anything).Once().Return(0, netTimeoutError{})
+
+	n, err := suite.conn.Read(make([]byte, 10))
+	suite.Equal(0, n)
+
+	netErr, ok := err.(net.Error) //nolint: errorlint
+	suite.True(ok)
+	suite.True(netErr.Timeout())
+}
+
+func (suite *ConnIdleTimeoutTestSuite) TestSharedTrackerPreventsFalseTimeout() {
+	connMock2 := &testlib.EssentialsConnMock{}
+	conn2 := connIdleTimeout{
+		Conn:    connMock2,
+		tracker: suite.tracker,
+	}
+
+	connMock2.On("SetWriteDeadline", mock.Anything).Return(nil)
+	connMock2.On("Write", mock.Anything).Once().Return(5, nil)
+
+	_, _ = conn2.Write(make([]byte, 5))
+
+	suite.connMock.On("SetReadDeadline", mock.Anything).Return(nil)
+	suite.connMock.On("Read", mock.Anything).Once().Return(0, netTimeoutError{})
+	suite.connMock.On("Read", mock.Anything).Once().Return(3, nil)
+
+	n, err := suite.conn.Read(make([]byte, 10))
+	suite.NoError(err)
+	suite.Equal(3, n)
+
+	connMock2.AssertExpectations(suite.T())
+}
+
+func (suite *ConnIdleTimeoutTestSuite) TestWriteOk() {
+	suite.connMock.On("SetWriteDeadline", mock.Anything).Return(nil)
+	suite.connMock.On("Write", mock.Anything).Once().Return(5, nil)
+
+	n, err := suite.conn.Write(make([]byte, 5))
+	suite.NoError(err)
+	suite.Equal(5, n)
+}
+
+func (suite *ConnIdleTimeoutTestSuite) TestWriteErr() {
+	suite.connMock.On("SetWriteDeadline", mock.Anything).Return(nil)
+	suite.connMock.On("Write", mock.Anything).Once().Return(0, io.EOF)
+
+	n, err := suite.conn.Write(make([]byte, 5))
+	suite.True(errors.Is(err, io.EOF))
+	suite.Equal(0, n)
+}
+
 func TestConnTraffic(t *testing.T) {
 	t.Parallel()
 	suite.Run(t, &ConnTrafficTestSuite{})
@@ -305,3 +446,13 @@ func TestConnProxyProtocol(t *testing.T) {
 	t.Parallel()
 	suite.Run(t, &ConnProxyProtocolTestSuite{})
 }
+
+func TestIdleTracker(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &IdleTrackerTestSuite{})
+}
+
+func TestConnIdleTimeout(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &ConnIdleTimeoutTestSuite{})
+}

mtglib/internal/dc/view.go

@@ -5,15 +5,19 @@ type dcView struct {
 }
 
 func (d dcView) getV4(dc int) []Addr {
-	addrs := d.publicConfigs.getV4(dc)
+	var addrs []Addr
+
 	addrs = append(addrs, defaultDCAddrSet.getV4(dc)...)
+	addrs = append(addrs, d.publicConfigs.getV4(dc)...)
 
 	return addrs
 }
 
 func (d dcView) getV6(dc int) []Addr {
-	addrs := d.publicConfigs.getV6(dc)
+	var addrs []Addr
+
 	addrs = append(addrs, defaultDCAddrSet.getV6(dc)...)
+	addrs = append(addrs, d.publicConfigs.getV6(dc)...)
 
 	return addrs
 }

mtglib/internal/doppel/clock.go

@@ -1,35 +0,0 @@
-package doppel
-
-import (
-	"context"
-	"time"
-)
-
-type Clock struct {
-	stats *Stats
-	tick  chan struct{}
-}
-
-func (c Clock) Start(ctx context.Context) {
-	tickTock := time.NewTimer(c.stats.Delay())
-	defer func() {
-		tickTock.Stop()
-		select {
-		case <-tickTock.C:
-		default:
-		}
-	}()
-
-	for {
-		select {
-		case <-ctx.Done():
-			return
-		case <-tickTock.C:
-			select {
-			case <-ctx.Done():
-			case c.tick <- struct{}{}:
-			}
-			tickTock.Reset(c.stats.Delay())
-		}
-	}
-}

mtglib/internal/doppel/clock_test.go

@@ -1,80 +0,0 @@
-package doppel
-
-import (
-	"context"
-	"sync"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/suite"
-)
-
-type ClockTestSuite struct {
-	suite.Suite
-
-	clock     Clock
-	wg        sync.WaitGroup
-	ctx       context.Context
-	ctxCancel context.CancelFunc
-}
-
-func (suite *ClockTestSuite) SetupTest() {
-	ctx, cancel := context.WithCancel(context.Background())
-
-	suite.ctx = ctx
-	suite.ctxCancel = cancel
-	suite.clock = Clock{
-		stats: &Stats{
-			k:      StatsDefaultK,
-			lambda: StatsDefaultLambda,
-		},
-		tick: make(chan struct{}),
-	}
-
-	suite.wg.Go(func() {
-		suite.clock.Start(suite.ctx)
-	})
-}
-
-func (suite *ClockTestSuite) TearDownTest() {
-	suite.ctxCancel()
-	suite.wg.Wait()
-}
-
-func (suite *ClockTestSuite) TestTicks() {
-	received := 0
-
-	for range 3 {
-		select {
-		case <-suite.clock.tick:
-			received++
-		case <-time.After(2 * time.Second):
-			suite.Fail("timed out waiting for tick")
-		}
-	}
-
-	suite.Equal(3, received)
-}
-
-func (suite *ClockTestSuite) TestStopsOnCancel() {
-	select {
-	case <-suite.clock.tick:
-	case <-time.After(2 * time.Second):
-		suite.Fail("timed out waiting for first tick")
-	}
-
-	suite.ctxCancel()
-
-	time.Sleep(50 * time.Millisecond)
-
-	select {
-	case <-suite.clock.tick:
-		suite.Fail("received tick after cancel")
-	default:
-	}
-}
-
-func TestClock(t *testing.T) {
-	t.Parallel()
-	suite.Run(t, &ClockTestSuite{})
-}

mtglib/internal/doppel/conn.go

@@ -4,11 +4,19 @@ import (
 	"bytes"
 	"context"
 	"sync"
+	"time"
 
 	"github.com/9seconds/mtg/v2/essentials"
 	"github.com/9seconds/mtg/v2/mtglib/internal/tls"
 )
 
+var doppelBufPool = sync.Pool{
+	New: func() any {
+		b := make([]byte, tls.MaxRecordSize)
+		return &b
+	},
+}
+
 type Conn struct {
 	essentials.Conn
 
@@ -18,7 +26,7 @@ type Conn struct {
 type connPayload struct {
 	ctx         context.Context
 	ctxCancel   context.CancelCauseFunc
-	clock       Clock
+	stats       Stats
 	wg          sync.WaitGroup
 	writeStream bytes.Buffer
 	writtenCond sync.Cond
@@ -39,23 +47,23 @@ func (c Conn) Write(p []byte) (int, error) {
 	return len(p), context.Cause(c.p.ctx)
 }
 
-func (c Conn) Start() {
-	c.p.wg.Go(func() {
-		c.start()
-	})
-}
-
 func (c Conn) start() {
-	buf := [tls.MaxRecordSize]byte{}
+	bp := doppelBufPool.Get().(*[]byte)
+	buf := *bp
+	defer doppelBufPool.Put(bp)
+
+	timer := time.NewTimer(c.p.stats.Delay())
+	defer timer.Stop()
 
 	for {
 		select {
 		case <-c.p.ctx.Done():
 			return
-		case <-c.p.clock.tick:
+		case <-timer.C:
+			timer.Reset(c.p.stats.Delay())
 		}
 
-		size := c.p.clock.stats.Size()
+		size := c.p.stats.Size()
 
 		c.p.writtenCond.L.Lock()
 		for c.p.writeStream.Len() == 0 && !c.p.done {
@@ -68,7 +76,7 @@ func (c Conn) start() {
 			continue
 		}
 
-		if err := tls.WriteRecordInPlace(c.Conn, buf[:], n); err != nil {
+		if err := tls.WriteRecordInPlace(c.Conn, buf, n); err != nil {
 			c.p.ctxCancel(err)
 			return
 		}
@@ -86,28 +94,22 @@ func (c Conn) Stop() {
 	c.p.wg.Wait()
 }
 
-func NewConn(ctx context.Context, conn essentials.Conn, stats *Stats) Conn {
+func NewConn(ctx context.Context, conn essentials.Conn, stats Stats) Conn {
 	ctx, cancel := context.WithCancelCause(ctx)
 	rv := Conn{
 		Conn: conn,
 		p: &connPayload{
 			ctx:       ctx,
 			ctxCancel: cancel,
+			stats:     stats,
 			writtenCond: sync.Cond{
 				L: &sync.Mutex{},
 			},
-			clock: Clock{
-				stats: stats,
-				tick:  make(chan struct{}),
-			},
 		},
 	}
 
 	rv.p.writeStream.Grow(tls.DefaultBufferSize)
 
-	rv.p.wg.Go(func() {
-		rv.p.clock.Start(ctx)
-	})
 	rv.p.wg.Go(func() {
 		rv.start()
 	})

mtglib/internal/doppel/conn_test.go

@@ -63,7 +63,7 @@ func (suite *ConnTestSuite) TearDownTest() {
 }
 
 func (suite *ConnTestSuite) makeConn() Conn {
-	return NewConn(suite.ctx, suite.connMock, &Stats{
+	return NewConn(suite.ctx, suite.connMock, Stats{
 		k:      2.0,
 		lambda: 0.01,
 	})
@@ -152,7 +152,7 @@ func (suite *ConnTestSuite) TestStopDoesNotDeadlockWhenStartIsWaiting() {
 			ctx, cancel := context.WithCancel(suite.ctx)
 			defer cancel()
 
-			c := NewConn(ctx, suite.connMock, &Stats{
+			c := NewConn(ctx, suite.connMock, Stats{
 				k:      2.0,
 				lambda: 0.01,
 			})

mtglib/internal/doppel/ganger.go

@@ -2,7 +2,9 @@ package doppel
 
 import (
 	"context"
+	"fmt"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/9seconds/mtg/v2/essentials"
@@ -12,8 +14,22 @@ const (
 	DoppelGangerMaxDurations  = 4096
 	DoppelGangerScoutRaidEach = 6 * time.Hour
 	DoppelGangerScoutRepeats  = 10
+
+	MinCertSizesToCalculate = 3
 )
 
+// NoiseParams holds the measured cert chain size for FakeTLS noise calibration.
+// If Mean is 0, the caller should use a legacy fallback.
+type NoiseParams struct {
+	Mean   int
+	Jitter int
+}
+
+type scoutRaidResult struct {
+	durations []time.Duration
+	certSizes []int
+}
+
 type gangerConnRequest struct {
 	ret     chan<- Conn
 	payload essentials.Conn
@@ -31,8 +47,11 @@ type Ganger struct {
 
 	drs bool
 
-	stats     *Stats
+	stats     Stats
 	durations []time.Duration
+	certSizes []int
+
+	noiseParams atomic.Pointer[NoiseParams]
 
 	connRequests chan gangerConnRequest
 }
@@ -48,6 +67,16 @@ func (g *Ganger) Run() {
 	})
 }
 
+// NoiseParams returns the current cert-size-based noise parameters.
+// Returns zero-value NoiseParams if not yet measured (caller should use fallback).
+func (g *Ganger) NoiseParams() NoiseParams {
+	if p := g.noiseParams.Load(); p != nil {
+		return *p
+	}
+
+	return NoiseParams{}
+}
+
 func (g *Ganger) NewConn(conn essentials.Conn) (Conn, error) {
 	rvChan := make(chan Conn)
 	req := gangerConnRequest{
@@ -81,10 +110,10 @@ func (g *Ganger) run() {
 		}
 	}()
 
-	scoutCollectedChan := make(chan []time.Duration)
+	scoutCollectedChan := make(chan scoutRaidResult)
 	currentScoutCollectedChan := scoutCollectedChan
 
-	updatedStatsChan := make(chan *Stats)
+	updatedStatsChan := make(chan Stats)
 
 	g.wg.Go(func() {
 		g.runScoutRaid(scoutCollectedChan)
@@ -94,18 +123,29 @@ func (g *Ganger) run() {
 		select {
 		case <-g.ctx.Done():
 			return
-		case durations := <-currentScoutCollectedChan:
-			g.durations = append(g.durations, durations...)
+		case result := <-currentScoutCollectedChan:
+			g.durations = append(g.durations, result.durations...)
 
 			if len(g.durations) > DoppelGangerMaxDurations {
 				copy(g.durations, g.durations[len(g.durations)-DoppelGangerMaxDurations:])
 				g.durations = g.durations[:DoppelGangerMaxDurations]
 			}
 
+			// Update cert sizes and recompute noise params.
+			g.certSizes = append(g.certSizes, result.certSizes...)
+			if len(g.certSizes) > DoppelGangerMaxDurations {
+				g.certSizes = g.certSizes[len(g.certSizes)-DoppelGangerMaxDurations:]
+			}
+
+			if len(g.certSizes) >= MinCertSizesToCalculate {
+				g.updateNoiseParams()
+			}
+
 			if len(g.durations) < MinDurationsToCalculate {
 				continue
 			}
 
+			durations := g.durations
 			currentScoutCollectedChan = nil
 			g.wg.Go(func() {
 				select {
@@ -129,8 +169,45 @@ func (g *Ganger) run() {
 	}
 }
 
-func (g *Ganger) runScoutRaid(rvChan chan<- []time.Duration) {
-	durations := []time.Duration{}
+func (g *Ganger) updateNoiseParams() {
+	if len(g.certSizes) == 0 {
+		return
+	}
+
+	sum := 0
+	for _, s := range g.certSizes {
+		sum += s
+	}
+
+	mean := sum / len(g.certSizes)
+
+	maxDev := 0
+	for _, s := range g.certSizes {
+		d := s - mean
+		if d < 0 {
+			d = -d
+		}
+
+		if d > maxDev {
+			maxDev = d
+		}
+	}
+
+	if maxDev < 100 {
+		maxDev = 100
+	}
+
+	np := &NoiseParams{Mean: mean, Jitter: maxDev}
+	g.noiseParams.Store(np)
+
+	g.logger.Info(fmt.Sprintf(
+		"updated noise params: mean=%d jitter=%d samples=%d",
+		mean, maxDev, len(g.certSizes),
+	))
+}
+
+func (g *Ganger) runScoutRaid(rvChan chan<- scoutRaidResult) {
+	var result scoutRaidResult
 
 	for range g.scoutRaidRepeats {
 		learned, err := g.scout.Learn(g.ctx)
@@ -138,13 +215,18 @@ func (g *Ganger) runScoutRaid(rvChan chan<- []time.Duration) {
 			g.logger.WarningError("cannot learn", err)
 			continue
 		}
-		durations = append(durations, learned...)
+
+		result.durations = append(result.durations, learned.Durations...)
+
+		if learned.CertSize > 0 {
+			result.certSizes = append(result.certSizes, learned.CertSize)
+		}
 	}
 
 	select {
 	case <-g.ctx.Done():
 		return
-	case rvChan <- durations:
+	case rvChan <- result:
 	}
 }
 
@@ -174,7 +256,7 @@ func NewGanger(
 		scoutRaidEach:    scoutEach,
 		scoutRaidRepeats: scoutRepeats,
 		drs:              drs,
-		stats: &Stats{
+		stats: Stats{
 			k:      StatsDefaultK,
 			lambda: StatsDefaultLambda,
 			drs:    drs,

mtglib/internal/doppel/scout.go

@@ -12,36 +12,46 @@ import (
 	"github.com/9seconds/mtg/v2/mtglib/internal/tls"
 )
 
+// ScoutResult holds measurements from a single scout HTTP request.
+type ScoutResult struct {
+	Durations []time.Duration
+	CertSize  int // total ApplicationData bytes during TLS handshake; 0 if unknown
+}
+
 type Scout struct {
 	network Network
 	urls    []string
 }
 
-func (s Scout) Learn(ctx context.Context) ([]time.Duration, error) {
-	var durations []time.Duration
+func (s Scout) Learn(ctx context.Context) (ScoutResult, error) {
+	var combined ScoutResult
 
 	for _, url := range s.urls {
 		learned, err := s.learn(ctx, url)
 		if err != nil {
-			return nil, err
+			return ScoutResult{}, err
 		}
 
-		durations = append(durations, learned...)
+		combined.Durations = append(combined.Durations, learned.Durations...)
+
+		if learned.CertSize > 0 && combined.CertSize == 0 {
+			combined.CertSize = learned.CertSize
+		}
 	}
 
-	return durations, nil
+	return combined, nil
 }
 
-func (s Scout) learn(ctx context.Context, url string) ([]time.Duration, error) {
+func (s Scout) learn(ctx context.Context, url string) (ScoutResult, error) {
 	client, results := s.makeClient()
 
 	if !strings.HasPrefix(url, "https://") {
-		return nil, fmt.Errorf("url %s must be https", url)
+		return ScoutResult{}, fmt.Errorf("url %s must be https", url)
 	}
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
-		return nil, err
+		return ScoutResult{}, err
 	}
 
 	resp, err := client.Do(req)
@@ -51,31 +61,62 @@ func (s Scout) learn(ctx context.Context, url string) ([]time.Duration, error) {
 		client.CloseIdleConnections()
 	}
 
-	if err != nil || len(results.data) == 0 {
-		return nil, err
+	if err != nil {
+		return ScoutResult{}, err
 	}
 
-	durations := []time.Duration{}
+	data, writeIndex := results.Snapshot()
+
+	if len(data) == 0 {
+		return ScoutResult{}, nil
+	}
+
+	var result ScoutResult
+
+	// Compute inter-record durations (existing logic).
 	lastTimestamp := time.Time{}
 
-	for i, v := range results.data {
+	for i, v := range data {
 		if v.recordType != tls.TypeApplicationData {
 			continue
 		}
 
 		if lastTimestamp.IsZero() {
 			if i > 0 {
-				lastTimestamp = results.data[i-1].timestamp
+				lastTimestamp = data[i-1].timestamp
 			} else {
 				lastTimestamp = v.timestamp
 			}
 		}
 
-		durations = append(durations, v.timestamp.Sub(lastTimestamp))
+		result.Durations = append(result.Durations, v.timestamp.Sub(lastTimestamp))
 		lastTimestamp = v.timestamp
 	}
 
-	return durations, nil
+	// Compute cert size: sum of ApplicationData payload between CCS and
+	// the first client Write (which marks the end of server handshake).
+	seenCCS := false
+	boundary := writeIndex
+	if boundary < 0 {
+		boundary = len(data)
+	}
+
+	for i, v := range data {
+		if i >= boundary {
+			break
+		}
+
+		if v.recordType == tls.TypeChangeCipherSpec {
+			seenCCS = true
+			continue
+		}
+
+		if seenCCS && v.recordType == tls.TypeApplicationData {
+			result.CertSize += v.payloadLen
+		}
+	}
+
+	return result, nil
 }
 
 func (s Scout) makeClient() (*http.Client, *ScoutConnCollected) {

mtglib/internal/doppel/scout_conn.go

@@ -14,9 +14,10 @@ type ScoutConn struct {
 
 	results *ScoutConnCollected
 	rawBuf  *bytes.Buffer
+	seenCCS bool
 }
 
-func (s ScoutConn) Read(p []byte) (int, error) {
+func (s *ScoutConn) Read(p []byte) (int, error) {
 	buf := &bytes.Buffer{}
 
 	for {
@@ -31,7 +32,11 @@ func (s ScoutConn) Read(p []byte) (int, error) {
 			return 0, err
 		}
 
-		s.results.Add(recordType)
+		if recordType == tls.TypeChangeCipherSpec {
+			s.seenCCS = true
+		}
+
+		s.results.Add(recordType, int(length))
 		s.rawBuf.Write([]byte{recordType})
 		s.rawBuf.Write(tls.TLSVersion[:])
 
@@ -45,11 +50,19 @@ func (s ScoutConn) Read(p []byte) (int, error) {
 	}
 }
 
-func NewScoutConn(conn essentials.Conn, results *ScoutConnCollected) ScoutConn {
+func (s *ScoutConn) Write(p []byte) (int, error) {
+	if s.seenCCS {
+		s.results.MarkWrite()
+	}
+
+	return s.Conn.Write(p)
+}
+
+func NewScoutConn(conn essentials.Conn, results *ScoutConnCollected) *ScoutConn {
 	rawBuf := &bytes.Buffer{}
 	rawBuf.Grow(tls.MaxRecordSize)
 
-	return ScoutConn{
+	return &ScoutConn{
 		Conn:    tls.New(conn, false, false),
 		results: results,
 		rawBuf:  rawBuf,

mtglib/internal/doppel/scout_conn_collected.go

@@ -1,6 +1,10 @@
 package doppel
 
-import "time"
+import (
+	"slices"
+	"sync"
+	"time"
+)
 
 const (
 	ScoutConnCollectedPreallocSize = 100
@@ -9,21 +13,47 @@ const (
 type ScoutConnResult struct {
 	timestamp  time.Time
 	recordType byte
+	payloadLen int
 }
 
 type ScoutConnCollected struct {
-	data []ScoutConnResult
+	mu         sync.Mutex
+	data       []ScoutConnResult
+	writeIndex int // index at which client first wrote post-handshake data; -1 if not set
 }
 
-func (s *ScoutConnCollected) Add(record byte) {
+func (s *ScoutConnCollected) Add(record byte, payloadLen int) {
+	s.mu.Lock()
 	s.data = append(s.data, ScoutConnResult{
 		timestamp:  time.Now(),
 		recordType: record,
+		payloadLen: payloadLen,
 	})
+	s.mu.Unlock()
+}
+
+// MarkWrite records the current data length as the handshake boundary.
+func (s *ScoutConnCollected) MarkWrite() {
+	s.mu.Lock()
+	if s.writeIndex < 0 {
+		s.writeIndex = len(s.data)
+	}
+	s.mu.Unlock()
+}
+
+// Snapshot returns a copy of the collected data and the write index.
+func (s *ScoutConnCollected) Snapshot() ([]ScoutConnResult, int) {
+	s.mu.Lock()
+	snapshot := slices.Clone(s.data)
+	writeIndex := s.writeIndex
+	s.mu.Unlock()
+
+	return snapshot, writeIndex
 }
 
 func NewScoutConnCollected() *ScoutConnCollected {
 	return &ScoutConnCollected{
-		data: make([]ScoutConnResult, 0, ScoutConnCollectedPreallocSize),
+		data:       make([]ScoutConnResult, 0, ScoutConnCollectedPreallocSize),
+		writeIndex: -1,
 	}
 }

mtglib/internal/doppel/scout_conn_collected_test.go

@@ -1,6 +1,7 @@
 package doppel
 
 import (
+	"sync"
 	"testing"
 	"time"
 
@@ -14,28 +15,71 @@ type ScoutConnCollectedTestSuite struct {
 
 func (suite *ScoutConnCollectedTestSuite) TestAddSingle() {
 	collected := NewScoutConnCollected()
-	collected.Add(tls.TypeApplicationData)
+	collected.Add(tls.TypeApplicationData, 100)
 
-	suite.Len(collected.data, 1)
-	suite.Equal(byte(tls.TypeApplicationData), collected.data[0].recordType)
+	data, _ := collected.Snapshot()
+
+	suite.Len(data, 1)
+	suite.Equal(byte(tls.TypeApplicationData), data[0].recordType)
 }
 
 func (suite *ScoutConnCollectedTestSuite) TestAddTimestampsAreMonotonic() {
 	collected := NewScoutConnCollected()
 
-	collected.Add(tls.TypeApplicationData)
+	collected.Add(tls.TypeApplicationData, 100)
 
 	time.Sleep(time.Microsecond)
-	collected.Add(tls.TypeApplicationData)
+	collected.Add(tls.TypeApplicationData, 100)
 
 	time.Sleep(time.Microsecond)
-	collected.Add(tls.TypeApplicationData)
+	collected.Add(tls.TypeApplicationData, 100)
 
-	for i := 1; i < len(collected.data); i++ {
-		suite.True(collected.data[i].timestamp.After(collected.data[i-1].timestamp))
+	data, _ := collected.Snapshot()
+
+	for i := 1; i < len(data); i++ {
+		suite.True(data[i].timestamp.After(data[i-1].timestamp))
 	}
 }
 
+func (suite *ScoutConnCollectedTestSuite) TestConcurrentAddSnapshot() {
+	collected := NewScoutConnCollected()
+
+	var wg sync.WaitGroup
+
+	wg.Add(3)
+
+	go func() {
+		defer wg.Done()
+
+		for i := 0; i < 1000; i++ {
+			collected.Add(tls.TypeApplicationData, i)
+		}
+	}()
+
+	go func() {
+		defer wg.Done()
+
+		for i := 0; i < 100; i++ {
+			collected.MarkWrite()
+		}
+	}()
+
+	go func() {
+		defer wg.Done()
+
+		for i := 0; i < 1000; i++ {
+			// call Snapshot concurrently to exercise the lock under -race
+			collected.Snapshot() //nolint:errcheck
+		}
+	}()
+
+	wg.Wait()
+
+	data, writeIndex := collected.Snapshot()
+	suite.Len(data, 1000)
+	suite.GreaterOrEqual(writeIndex, 0)
+}
+
 func TestScoutConnCollected(t *testing.T) {
 	t.Parallel()
 	suite.Run(t, &ScoutConnCollectedTestSuite{})

mtglib/internal/doppel/scout_test.go

@@ -22,9 +22,9 @@ func (suite *ScoutTestSuite) SetupSuite() {
 }
 
 func (suite *ScoutTestSuite) TestCollectResults() {
-	durations, err := suite.scout.Learn(suite.ctx)
+	result, err := suite.scout.Learn(suite.ctx)
 	suite.NoError(err)
-	suite.Less(3, len(durations))
+	suite.Less(3, len(result.Durations))
 }
 
 func (suite *ScoutTestSuite) TestCollectNothing() {

mtglib/internal/doppel/stats.go

@@ -112,7 +112,7 @@ func (d *Stats) Size() int {
 	return TLSRecordSizeMax
 }
 
-func NewStats(durations []time.Duration, drs bool) *Stats {
+func NewStats(durations []time.Duration, drs bool) Stats {
 	n := float64(len(durations))
 
 	// in milliseconds
@@ -162,7 +162,7 @@ func NewStats(durations []time.Duration, drs bool) *Stats {
 	// λ = (Σxᵢᵏ / n)^(1/k)
 	lambda := math.Pow(sumXK/n, 1.0/k)
 
-	return &Stats{
+	return Stats{
 		k:      k,
 		lambda: lambda,
 		drs:    drs,

mtglib/internal/relay/pool_settings_constrained.go

@@ -0,0 +1,13 @@
+//go:build mips || mipsle
+
+package relay
+
+import "github.com/9seconds/mtg/v2/mtglib/internal/tls"
+
+const (
+	// MIPS is quite short in resources, and usually it means that it will run
+	// on Microtiks, OpenWRT-based routers or similar hardware. I think it worth
+	// to sacrifice a number of read syscalls (read, CPU load) to shrink
+	// limited RAM resources.
+	bufPoolSize = tls.MaxRecordPayloadSize / 2
+)

mtglib/internal/relay/pool_settings_other.go

@@ -0,0 +1,9 @@
+//go:build !mips && !mipsle
+
+package relay
+
+import "github.com/9seconds/mtg/v2/mtglib/internal/tls"
+
+const (
+	bufPoolSize = tls.MaxRecordPayloadSize
+)

mtglib/internal/relay/pools.go

@@ -0,0 +1,18 @@
+package relay
+
+import "sync"
+
+var bufPool = sync.Pool{
+	New: func() any {
+		b := make([]byte, bufPoolSize)
+		return &b
+	},
+}
+
+func acquireBuffer() *[]byte {
+	return bufPool.Get().(*[]byte)
+}
+
+func releaseBuffer(p *[]byte) {
+	bufPool.Put(p)
+}

mtglib/internal/relay/relay.go

@@ -6,7 +6,6 @@ import (
 	"io"
 
 	"github.com/9seconds/mtg/v2/essentials"
-	"github.com/9seconds/mtg/v2/mtglib/internal/tls"
 )
 
 func Relay(ctx context.Context, log Logger, telegramConn, clientConn essentials.Conn) {
@@ -16,11 +15,11 @@ func Relay(ctx context.Context, log Logger, telegramConn, clientConn essentials.
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
-	go func() {
-		<-ctx.Done()
+	stop := context.AfterFunc(ctx, func() {
 		telegramConn.Close() //nolint: errcheck
 		clientConn.Close()   //nolint: errcheck
-	}()
+	})
+	defer stop()
 
 	closeChan := make(chan struct{})
 
@@ -36,12 +35,13 @@ func Relay(ctx context.Context, log Logger, telegramConn, clientConn essentials.
 }
 
 func pump(log Logger, src, dst essentials.Conn, direction string) {
-	var buf [tls.MaxRecordPayloadSize]byte
+	buf := acquireBuffer()
+	defer releaseBuffer(buf)
 
 	defer src.CloseRead()  //nolint: errcheck
 	defer dst.CloseWrite() //nolint: errcheck
 
-	n, err := io.CopyBuffer(src, dst, buf[:])
+	n, err := io.CopyBuffer(src, dst, *buf)
 
 	switch {
 	case err == nil:

mtglib/internal/tls/fake/client_side.go

@@ -11,8 +11,6 @@ import (
 	"net"
 	"slices"
 	"time"
-
-	"github.com/9seconds/mtg/v2/mtglib/internal/tls"
 )
 
 const (
@@ -56,25 +54,17 @@ func ReadClientHello(
 	//  4. New digest should be all 0 except of last 4 bytes
 	//  5. Last 4 bytes are little endian uint32 of UNIX timestamp when
 	//     this message was created.
-	handshakeCopyBuf := &bytes.Buffer{}
-	reader := io.TeeReader(conn, handshakeCopyBuf)
-
-	reader, err := parseTLSHeader(reader)
+	clientHelloCopy, handshakeReader, err := parseClientHello(conn)
 	if err != nil {
-		return nil, fmt.Errorf("cannot parse tls header: %w", err)
+		return nil, fmt.Errorf("cannot read client hello: %w", err)
 	}
 
-	reader, err = parseHandshakeHeader(reader)
-	if err != nil {
-		return nil, fmt.Errorf("cannot parse handshake header: %w", err)
-	}
-
-	hello, err := parseHandshake(reader)
+	hello, err := parseHandshake(handshakeReader)
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse handshake: %w", err)
 	}
 
-	sniHostnames, err := parseSNI(reader)
+	sniHostnames, err := parseSNI(handshakeReader)
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse SNI: %w", err)
 	}
@@ -85,10 +75,10 @@ func ReadClientHello(
 
 	digest := hmac.New(sha256.New, secret)
 	// we write a copy of the handshake with client random all nullified.
-	digest.Write(handshakeCopyBuf.Next(RandomOffset))
-	handshakeCopyBuf.Next(RandomLen)
+	digest.Write(clientHelloCopy.Next(RandomOffset))
+	clientHelloCopy.Next(RandomLen)
 	digest.Write(emptyRandom[:])
-	digest.Write(handshakeCopyBuf.Bytes())
+	digest.Write(clientHelloCopy.Bytes())
 
 	computed := digest.Sum(nil)
 
@@ -110,58 +100,6 @@ func ReadClientHello(
 	return hello, nil
 }
 
-func parseTLSHeader(r io.Reader) (io.Reader, error) {
-	// record_type(1) + version(2) + size(2)
-	//   16 - type is 0x16 (handshake record)
-	//   03 01 - protocol version is "3,1" (also known as TLS 1.0)
-	//   00 f8 - 0xF8 (248) bytes of handshake message follows
-	header := [1 + 2 + 2]byte{}
-
-	if _, err := io.ReadFull(r, header[:]); err != nil {
-		return nil, fmt.Errorf("cannot read record header: %w", err)
-	}
-
-	if header[0] != tls.TypeHandshake {
-		return nil, fmt.Errorf("unexpected record type %#x", header[0])
-	}
-
-	if header[1] != 3 || header[2] != 1 {
-		return nil, fmt.Errorf("unexpected protocol version %#x %#x", header[1], header[2])
-	}
-
-	length := int64(binary.BigEndian.Uint16(header[3:]))
-	buf := &bytes.Buffer{}
-
-	_, err := io.CopyN(buf, r, length)
-
-	return buf, err
-}
-
-func parseHandshakeHeader(r io.Reader) (io.Reader, error) {
-	// type(1) + size(3 / uint24)
-	// 01 - handshake message type 0x01 (client hello)
-	// 00 00 f4 - 0xF4 (244) bytes of client hello data follows
-	header := [1 + 3]byte{}
-
-	if _, err := io.ReadFull(r, header[:]); err != nil {
-		return nil, fmt.Errorf("cannot read handshake header: %w", err)
-	}
-
-	if header[0] != TypeHandshakeClient {
-		return nil, fmt.Errorf("incorrect handshake type: %#x", header[0])
-	}
-
-	// unfortunately there is not uint24 in golang, so we just reust header
-	header[0] = 0
-
-	length := int64(binary.BigEndian.Uint32(header[:]))
-	buf := &bytes.Buffer{}
-
-	_, err := io.CopyN(buf, r, length)
-
-	return buf, err
-}
-
 func parseHandshake(r io.Reader) (*ClientHello, error) {
 	//  A protocol version of "3,3" (meaning TLS 1.2) is given.
 	header := [2]byte{}

mtglib/internal/tls/fake/client_side_test.go

@@ -3,8 +3,10 @@ package fake_test
 import (
 	"bytes"
 	"encoding/binary"
+	"encoding/json"
 	"errors"
 	"io"
+	"os"
 	"testing"
 	"time"
 
@@ -393,3 +395,273 @@ func TestParseClientHelloSNI(t *testing.T) {
 	t.Parallel()
 	suite.Run(t, &ParseClientHelloSNITestSuite{})
 }
+
+// fragmentTLSRecord splits a single TLS record into n TLS records by
+// dividing the payload into roughly equal parts. Each part gets its own
+// TLS record header with the same record type and version.
+func fragmentTLSRecord(t testing.TB, full []byte, n int) []byte {
+	t.Helper()
+
+	recordType := full[0]
+	version := full[1:3]
+	payload := full[tls.SizeHeader:]
+
+	chunkSize := len(payload) / n
+	result := &bytes.Buffer{}
+
+	for i := 0; i < n; i++ {
+		start := i * chunkSize
+		end := start + chunkSize
+
+		if i == n-1 {
+			end = len(payload)
+		}
+
+		chunk := payload[start:end]
+		result.WriteByte(recordType)
+		result.Write(version)
+		require.NoError(t, binary.Write(result, binary.BigEndian, uint16(len(chunk))))
+		result.Write(chunk)
+	}
+
+	return result.Bytes()
+}
+
+// splitPayloadAt creates two TLS records from a single record by splitting
+// the payload at the given byte position.
+func splitPayloadAt(t testing.TB, full []byte, pos int) []byte {
+	t.Helper()
+
+	payload := full[tls.SizeHeader:]
+	buf := &bytes.Buffer{}
+
+	buf.WriteByte(tls.TypeHandshake)
+	buf.Write(full[1:3])
+	require.NoError(t, binary.Write(buf, binary.BigEndian, uint16(pos)))
+	buf.Write(payload[:pos])
+
+	buf.WriteByte(tls.TypeHandshake)
+	buf.Write(full[1:3])
+	require.NoError(t, binary.Write(buf, binary.BigEndian, uint16(len(payload)-pos)))
+	buf.Write(payload[pos:])
+
+	return buf.Bytes()
+}
+
+type ParseClientHelloFragmentedTestSuite struct {
+	suite.Suite
+
+	secret   mtglib.Secret
+	snapshot *clientHelloSnapshot
+}
+
+func (s *ParseClientHelloFragmentedTestSuite) SetupSuite() {
+	parsed, err := mtglib.ParseSecret(
+		"ee367a189aee18fa31c190054efd4a8e9573746f726167652e676f6f676c65617069732e636f6d",
+	)
+	require.NoError(s.T(), err)
+
+	s.secret = parsed
+
+	fileData, err := os.ReadFile("testdata/client-hello-ok-19dfe38384b9884b.json")
+	require.NoError(s.T(), err)
+
+	s.snapshot = &clientHelloSnapshot{}
+	require.NoError(s.T(), json.Unmarshal(fileData, s.snapshot))
+}
+
+func (s *ParseClientHelloFragmentedTestSuite) makeConn(data []byte) *parseClientHelloConnMock {
+	readBuf := &bytes.Buffer{}
+	readBuf.Write(data)
+
+	connMock := &parseClientHelloConnMock{
+		readBuf: readBuf,
+	}
+
+	connMock.
+		On("SetReadDeadline", mock.AnythingOfType("time.Time")).
+		Twice().
+		Return(nil)
+
+	return connMock
+}
+
+func (s *ParseClientHelloFragmentedTestSuite) TestReassemblySuccess() {
+	full := s.snapshot.GetFull()
+
+	tests := []struct {
+		name string
+		data []byte
+	}{
+		{"two equal fragments", fragmentTLSRecord(s.T(), full, 2)},
+		{"three equal fragments", fragmentTLSRecord(s.T(), full, 3)},
+		{"single byte first fragment", splitPayloadAt(s.T(), full, 1)},
+		{"three byte first fragment", splitPayloadAt(s.T(), full, 3)},
+	}
+
+	for _, tt := range tests {
+		s.Run(tt.name, func() {
+			connMock := s.makeConn(tt.data)
+			defer connMock.AssertExpectations(s.T())
+
+			hello, err := fake.ReadClientHello(
+				connMock,
+				s.secret.Key[:],
+				s.secret.Host,
+				TolerateTime,
+			)
+			s.Require().NoError(err)
+
+			s.Equal(s.snapshot.GetRandom(), hello.Random[:])
+			s.Equal(s.snapshot.GetSessionID(), hello.SessionID)
+			s.Equal(uint16(s.snapshot.CipherSuite), hello.CipherSuite)
+		})
+	}
+}
+
+func (s *ParseClientHelloFragmentedTestSuite) TestReassemblyErrors() {
+	full := s.snapshot.GetFull()
+	payload := full[tls.SizeHeader:]
+
+	tests := []struct {
+		name      string
+		buildData func() []byte
+		errMsg    string
+	}{
+		{
+			name: "wrong continuation record type",
+			buildData: func() []byte {
+				buf := &bytes.Buffer{}
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write(full[1:3])
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
+				buf.Write(payload[:10])
+				// Wrong type: application data instead of handshake
+				buf.WriteByte(tls.TypeApplicationData)
+				buf.Write(full[1:3])
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(len(payload)-10)))
+				buf.Write(payload[10:])
+				return buf.Bytes()
+			},
+			errMsg: "unexpected record type",
+		},
+		{
+			name: "too many continuation records",
+			buildData: func() []byte {
+				// Handshake header claiming 256 bytes, but we only send 1 byte per continuation
+				handshakePayload := []byte{0x01, 0x00, 0x01, 0x00}
+				buf := &bytes.Buffer{}
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write([]byte{3, 1})
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(len(handshakePayload))))
+				buf.Write(handshakePayload)
+				for range 11 {
+					buf.WriteByte(tls.TypeHandshake)
+					buf.Write([]byte{3, 1})
+					require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(1)))
+					buf.WriteByte(0xAB)
+				}
+				return buf.Bytes()
+			},
+			errMsg: "too many fragments",
+		},
+		{
+			name: "zero-length continuation record",
+			buildData: func() []byte {
+				buf := &bytes.Buffer{}
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write(full[1:3])
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
+				buf.Write(payload[:10])
+				// Valid header but zero-length payload
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write(full[1:3])
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(0)))
+				return buf.Bytes()
+			},
+			errMsg: "cannot read record header",
+		},
+		{
+			name: "wrong continuation record version",
+			buildData: func() []byte {
+				buf := &bytes.Buffer{}
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write(full[1:3])
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
+				buf.Write(payload[:10])
+				// Wrong version: 3.3 instead of 3.1
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write([]byte{3, 3})
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(len(payload)-10)))
+				buf.Write(payload[10:])
+				return buf.Bytes()
+			},
+			errMsg: "unexpected protocol version",
+		},
+		{
+			name: "handshake message too large",
+			buildData: func() []byte {
+				// Handshake header claiming 0x010000 (65536) bytes — exceeds 0xFFFF limit
+				handshakePayload := []byte{0x01, 0x01, 0x00, 0x00}
+				buf := &bytes.Buffer{}
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write([]byte{3, 1})
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(len(handshakePayload))))
+				buf.Write(handshakePayload)
+				return buf.Bytes()
+			},
+			errMsg: "cannot read record header",
+		},
+		{
+			name: "truncated continuation record header",
+			buildData: func() []byte {
+				buf := &bytes.Buffer{}
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write(full[1:3])
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
+				buf.Write(payload[:10])
+				// Connection ends mid-header (only 2 bytes)
+				buf.WriteByte(tls.TypeHandshake)
+				buf.WriteByte(3)
+				return buf.Bytes()
+			},
+			errMsg: "cannot read record header",
+		},
+		{
+			name: "truncated continuation record payload",
+			buildData: func() []byte {
+				buf := &bytes.Buffer{}
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write(full[1:3])
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(10)))
+				buf.Write(payload[:10])
+				// Claims 100 bytes but no payload follows
+				buf.WriteByte(tls.TypeHandshake)
+				buf.Write(full[1:3])
+				require.NoError(s.T(), binary.Write(buf, binary.BigEndian, uint16(100)))
+				return buf.Bytes()
+			},
+			errMsg: "EOF",
+		},
+	}
+
+	for _, tt := range tests {
+		s.Run(tt.name, func() {
+			connMock := s.makeConn(tt.buildData())
+			defer connMock.AssertExpectations(s.T())
+
+			_, err := fake.ReadClientHello(
+				connMock,
+				s.secret.Key[:],
+				s.secret.Host,
+				TolerateTime,
+			)
+			s.ErrorContains(err, tt.errMsg)
+		})
+	}
+}
+
+func TestParseClientHelloFragmented(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &ParseClientHelloFragmentedTestSuite{})
+}

mtglib/internal/tls/fake/server_side.go

@@ -9,11 +9,18 @@ import (
 	"io"
 	rnd "math/rand/v2"
 
-	"github.com/9seconds/mtg/v2/mtglib/internal/doppel"
 	"github.com/9seconds/mtg/v2/mtglib/internal/tls"
 	"golang.org/x/crypto/curve25519"
 )
 
+// NoiseParams controls the size of the fake ApplicationData record
+// in ServerHello. If Mean is 0, the legacy random range (2500-4700)
+// is used.
+type NoiseParams struct {
+	Mean   int
+	Jitter int
+}
+
 const (
 	TypeHandshakeServer = 0x02
 	ChangeCipherValue   = 0x01
@@ -33,13 +40,13 @@ var serverHelloSuffix = []byte{
 	0x00, 0x20, // 32 bytes of key
 }
 
-func SendServerHello(w io.Writer, secret []byte, clientHello *ClientHello) error {
+func SendServerHello(w io.Writer, secret []byte, clientHello *ClientHello, noise NoiseParams) error {
 	buf := &bytes.Buffer{}
 	buf.Grow(tls.MaxRecordSize)
 
 	generateServerHello(buf, clientHello)
 	generateChangeCipherValue(buf)
-	generateNoise(buf)
+	generateNoise(buf, noise)
 
 	packet := buf.Bytes()
 	digest := hmac.New(sha256.New, secret)
@@ -125,19 +132,31 @@ func generateChangeCipherValue(buf *bytes.Buffer) {
 	buf.WriteByte(ChangeCipherValue)
 }
 
-func generateNoise(buf *bytes.Buffer) {
-	data := make(
-		[]byte,
-		int64(
-			doppel.TLSRecordSizeStart+rnd.IntN(
-				doppel.TLSRecordSizeAccel-doppel.TLSRecordSizeStart,
-			),
-		),
-	)
+// generateNoise writes a single ApplicationData record mimicking the combined
+// size of a real TLS 1.3 encrypted server handshake (EncryptedExtensions +
+// Certificate chain + CertificateVerify + Finished).
+//
+// NOTE: Must be exactly ONE ApplicationData record — the Telegram client reads
+// ServerHello + CCS + 1 ApplicationData and computes HMAC over all three.
+// Multiple records would cause HMAC mismatch and connection failure.
+func generateNoise(buf *bytes.Buffer, noise NoiseParams) {
+	var size int
 
-	if _, err := rand.Read(data[:]); err != nil {
+	if noise.Mean > 0 && noise.Jitter > 0 {
+		// Calibrated: use measured cert chain size ± jitter.
+		size = noise.Mean - noise.Jitter + rnd.IntN(2*noise.Jitter)
+		if size < 1000 {
+			size = 1000
+		}
+	} else {
+		// Legacy fallback: random in 2500-4700 range.
+		size = 2500 + rnd.IntN(2200)
+	}
+
+	data := make([]byte, size)
+	if _, err := rand.Read(data); err != nil {
 		panic(err)
 	}
 
-	tls.WriteRecord(buf, data[:]) //nolint: errcheck
+	tls.WriteRecord(buf, data) //nolint: errcheck
 }

mtglib/internal/tls/fake/server_side_test.go

@@ -8,7 +8,6 @@ import (
 	"testing"
 
 	"github.com/9seconds/mtg/v2/mtglib"
-	"github.com/9seconds/mtg/v2/mtglib/internal/doppel"
 	"github.com/9seconds/mtg/v2/mtglib/internal/tls"
 	"github.com/9seconds/mtg/v2/mtglib/internal/tls/fake"
 	"github.com/stretchr/testify/suite"
@@ -39,7 +38,7 @@ func (suite *SendServerHelloTestSuite) SetupTest() {
 }
 
 func (suite *SendServerHelloTestSuite) TestRecordStructure() {
-	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello)
+	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello, fake.NoiseParams{})
 	suite.NoError(err)
 
 	var rec bytes.Buffer
@@ -59,13 +58,13 @@ func (suite *SendServerHelloTestSuite) TestRecordStructure() {
 	recordType, length, err := tls.ReadRecord(suite.buf, &rec)
 	suite.NoError(err)
 	suite.Equal(byte(tls.TypeApplicationData), recordType)
-	suite.Greater(length, int64(doppel.TLSRecordSizeStart))
+	suite.Greater(length, int64(2500))
 
 	suite.Empty(suite.buf.Bytes())
 }
 
 func (suite *SendServerHelloTestSuite) TestHMAC() {
-	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello)
+	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello, fake.NoiseParams{})
 	suite.NoError(err)
 
 	packet := make([]byte, suite.buf.Len())
@@ -83,7 +82,7 @@ func (suite *SendServerHelloTestSuite) TestHMAC() {
 }
 
 func (suite *SendServerHelloTestSuite) TestHandshakePayload() {
-	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello)
+	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello, fake.NoiseParams{})
 	suite.NoError(err)
 
 	packet := suite.buf.Bytes()
@@ -105,7 +104,7 @@ func (suite *SendServerHelloTestSuite) TestHandshakePayload() {
 }
 
 func (suite *SendServerHelloTestSuite) TestChangeCipherSpec() {
-	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello)
+	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello, fake.NoiseParams{})
 	suite.NoError(err)
 
 	// Skip first record
@@ -124,6 +123,33 @@ func (suite *SendServerHelloTestSuite) TestChangeCipherSpec() {
 	suite.Equal([]byte{fake.ChangeCipherValue}, rec.Bytes())
 }
 
+func (suite *SendServerHelloTestSuite) TestCalibratedNoiseSize() {
+	noise := fake.NoiseParams{Mean: 6480, Jitter: 100}
+	err := fake.SendServerHello(suite.buf, suite.secret.Key[:], suite.hello, noise)
+	suite.NoError(err)
+
+	var rec bytes.Buffer
+
+	// Skip ServerHello
+	_, _, err = tls.ReadRecord(suite.buf, &rec)
+	suite.NoError(err)
+
+	// Skip ChangeCipherSpec
+	rec.Reset()
+	_, _, err = tls.ReadRecord(suite.buf, &rec)
+	suite.NoError(err)
+
+	// Read noise ApplicationData
+	rec.Reset()
+	recordType, length, err := tls.ReadRecord(suite.buf, &rec)
+	suite.NoError(err)
+	suite.Equal(byte(tls.TypeApplicationData), recordType)
+
+	// Should be within mean ± jitter range.
+	suite.GreaterOrEqual(length, int64(noise.Mean-noise.Jitter))
+	suite.LessOrEqual(length, int64(noise.Mean+noise.Jitter))
+}
+
 func TestSendServerHello(t *testing.T) {
 	t.Parallel()
 	suite.Run(t, &SendServerHelloTestSuite{})

mtglib/internal/tls/fake/utils.go

@@ -0,0 +1,158 @@
+package fake
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+
+	"github.com/9seconds/mtg/v2/mtglib/internal/tls"
+)
+
+const (
+	maxFragmentsCount = 10
+)
+
+var ErrTooManyFragments = errors.New("too many fragments")
+
+// https://datatracker.ietf.org/doc/html/rfc5246#section-6.2.1
+// client hello can be fragmented in a series of packets:
+//
+//	Bytes on the wire:
+//
+// 16 03 01 00 F8 01 00 00 F4 03 03 [32 bytes random] [session_id] [ciphers] [SNI...]
+// ├─────────────┤├──────────────────────────────────────────────────────────────────┤
+//
+//	TLS record       Payload (248 bytes)
+//	header (5B)
+//
+//	16    = Handshake
+//	03 01 = TLS 1.0 (record layer version)
+//	00 F8 = 248 bytes follow
+//
+//	01       = ClientHello (handshake type)
+//	00 00 F4 = 244 bytes of handshake body
+//	03 03    = TLS 1.2 (actual protocol version)
+//	...rest of ClientHello...
+//
+// Fragmented record look like:
+//
+//	Record 1:
+//
+// 16 03 01 00 03 01 00 00
+// ├─────────────┤├──────┤
+//
+//	TLS header    3 bytes of payload
+//
+//	16    = Handshake
+//	03 01 = TLS 1.0
+//	00 03 = only 3 bytes follow
+//
+//	01       = ClientHello type
+//	00 00    = first 2 bytes of the uint24 length (INCOMPLETE!)
+//
+// Record 2:
+// 16 03 01 00 F5 F4 03 03 [32 bytes random] [session_id] [ciphers] [SNI...]
+// ├─────────────┤├────────────────────────────────────────────────────────────┤
+//
+//	TLS header    remaining 245 bytes of payload
+//
+//	16    = Handshake
+//	03 01 = TLS 1.0
+//	00 F5 = 245 bytes follow
+//
+//	F4    = last byte of uint24 length (now complete: 00 00 F4 = 244)
+//	03 03 = TLS 1.2
+//	...rest of ClientHello continues...
+//
+// So it means that there could be a series of handshake packets of different
+// lengths. The goal of this function is to concatenate these fragments.
+type fragmentedHandshakeReader struct {
+	r             io.Reader
+	buf           bytes.Buffer
+	readFragments int
+}
+
+func (f *fragmentedHandshakeReader) Read(p []byte) (int, error) {
+	if n, err := f.buf.Read(p); err == nil {
+		return n, nil
+	}
+
+	f.buf.Reset()
+
+	for f.buf.Len() == 0 {
+		if f.readFragments > maxFragmentsCount {
+			return 0, ErrTooManyFragments
+		}
+
+		if err := f.parseNextFragment(); err != nil {
+			return 0, err
+		}
+
+		f.readFragments++
+	}
+
+	return f.buf.Read(p)
+}
+
+func (f *fragmentedHandshakeReader) parseNextFragment() error {
+	// record_type(1) + version(2) + size(2)
+	//   16 - type is 0x16 (handshake record)
+	//   03 01 - protocol version is "3,1" (also known as TLS 1.0)
+	//   00 f8 - 0xF8 (248) bytes of handshake message follows
+	header := [1 + 2 + 2]byte{}
+
+	if _, err := io.ReadFull(f.r, header[:]); err != nil {
+		return fmt.Errorf("cannot read record header: %w", err)
+	}
+
+	if header[0] != tls.TypeHandshake {
+		return fmt.Errorf("unexpected record type %#x", header[0])
+	}
+
+	if header[1] != 3 || header[2] != 1 {
+		return fmt.Errorf("unexpected protocol version %#x %#x", header[1], header[2])
+	}
+
+	length := int64(binary.BigEndian.Uint16(header[3:]))
+	_, err := io.CopyN(&f.buf, f.r, length)
+
+	return err
+}
+
+func parseClientHello(r io.Reader) (*bytes.Buffer, *bytes.Buffer, error) {
+	r = &fragmentedHandshakeReader{r: r}
+	header := [1 + 3]byte{}
+
+	if _, err := io.ReadFull(r, header[:]); err != nil {
+		return nil, nil, fmt.Errorf("cannot read handshake header: %w", err)
+	}
+
+	if header[0] != TypeHandshakeClient {
+		return nil, nil, fmt.Errorf("incorrect handshake type: %#x", header[0])
+	}
+
+	// unfortunately there is not uint24 in golang, so we just reuse header
+	header[0] = 0
+	length := int64(binary.BigEndian.Uint32(header[:]))
+
+	clientHelloCopy := &bytes.Buffer{}
+	clientHelloCopy.Write([]byte{tls.TypeHandshake, 3, 1})
+	binary.Write( //nolint: errcheck
+		clientHelloCopy,
+		binary.BigEndian,
+		// 1 for handshake type
+		// 3 for handshake length
+		uint16(1+3+length),
+	)
+	clientHelloCopy.WriteByte(TypeHandshakeClient)
+	clientHelloCopy.Write(header[1:])
+
+	handshakeCopy := &bytes.Buffer{}
+	writer := io.MultiWriter(clientHelloCopy, handshakeCopy)
+
+	_, err := io.CopyN(writer, r, length)
+
+	return clientHelloCopy, handshakeCopy, err
+}

mtglib/proxy.go

@@ -27,6 +27,7 @@ type Proxy struct {
 
 	allowFallbackOnUnknownDC    bool
 	tolerateTimeSkewness        time.Duration
+	idleTimeout                 time.Duration
 	domainFrontingPort          int
 	domainFrontingIP            string
 	domainFrontingProxyProtocol bool
@@ -65,10 +66,10 @@ func (p *Proxy) ServeConn(conn essentials.Conn) {
 	ctx := newStreamContext(p.ctx, p.logger, conn)
 	defer ctx.Close()
 
-	go func() {
-		<-ctx.Done()
+	stop := context.AfterFunc(ctx, func() {
 		ctx.Close()
-	}()
+	})
+	defer stop()
 
 	p.eventStream.Send(ctx, NewEventStart(ctx.streamID, ctx.ClientIP()))
 	ctx.logger.Info("Stream has been started")
@@ -101,11 +102,13 @@ func (p *Proxy) ServeConn(conn essentials.Conn) {
 		return
 	}
 
+	tracker := newIdleTracker(p.idleTimeout)
+
 	relay.Relay(
 		ctx,
 		ctx.logger.Named("relay"),
-		ctx.telegramConn,
-		ctx.clientConn,
+		connIdleTimeout{Conn: ctx.telegramConn, tracker: tracker},
+		connIdleTimeout{Conn: ctx.clientConn, tracker: tracker},
 	)
 }
 
@@ -151,6 +154,7 @@ func (p *Proxy) Serve(listener net.Listener) error {
 		case errors.Is(err, ants.ErrPoolClosed):
 			return nil
 		case errors.Is(err, ants.ErrPoolOverload):
+			conn.Close() //nolint: errcheck
 			logger.Info("connection was concurrency limited")
 			p.eventStream.Send(p.ctx, NewEventConcurrencyLimited())
 		}
@@ -192,7 +196,10 @@ func (p *Proxy) doFakeTLSHandshake(ctx *streamContext) bool {
 		return false
 	}
 
-	if err := fake.SendServerHello(ctx.clientConn, p.secret.Key[:], clientHello); err != nil {
+	gangerNoise := p.doppelGanger.NoiseParams()
+	noiseParams := fake.NoiseParams{Mean: gangerNoise.Mean, Jitter: gangerNoise.Jitter}
+
+	if err := fake.SendServerHello(ctx.clientConn, p.secret.Key[:], clientHello, noiseParams); err != nil {
 		p.logger.InfoError("cannot send welcome packet", err)
 		return false
 	}
@@ -300,11 +307,13 @@ func (p *Proxy) doDomainFronting(ctx *streamContext, conn *connRewind) {
 		stream:   p.eventStream,
 	}
 
+	tracker := newIdleTracker(p.idleTimeout)
+
 	relay.Relay(
 		ctx,
 		ctx.logger.Named("domain-fronting"),
-		frontConn,
-		conn,
+		connIdleTimeout{Conn: frontConn, tracker: tracker},
+		connIdleTimeout{Conn: conn, tracker: tracker},
 	)
 }
 
@@ -336,6 +345,7 @@ func NewProxy(opts ProxyOpts) (*Proxy, error) {
 		domainFrontingPort:       opts.getDomainFrontingPort(),
 		domainFrontingIP:         opts.DomainFrontingIP,
 		tolerateTimeSkewness:     opts.getTolerateTimeSkewness(),
+		idleTimeout:              opts.getIdleTimeout(),
 		allowFallbackOnUnknownDC: opts.AllowFallbackOnUnknownDC,
 		telegram:                 tg,
 		doppelGanger: doppel.NewGanger(

mtglib/proxy_opts.go

@@ -215,6 +215,14 @@ func (p ProxyOpts) getPreferIP() string {
 	return p.PreferIP
 }
 
+func (p ProxyOpts) getIdleTimeout() time.Duration {
+	if p.IdleTimeout == 0 {
+		return time.Minute
+	}
+
+	return p.IdleTimeout
+}
+
 func (p ProxyOpts) getLogger(name string) Logger {
 	return p.Logger.Named(name)
 }

mtglib/proxy_test.go

@@ -175,7 +175,7 @@ func (suite *ProxyTestSuite) TestHTTPSRequest() {
 	addr := fmt.Sprintf("https://%s/headers", suite.ProxyAddress())
 
 	resp, err := client.Get(addr) //nolint: noctx
-	suite.NoError(err)
+	suite.Require().NoError(err)
 
 	defer resp.Body.Close() //nolint: errcheck
 

run_profile_tag_prof.go

@@ -3,7 +3,6 @@
 package main
 
 import (
-	"fmt"
 	"net"
 	"net/http"
 	_ "net/http/pprof" //nolint: gosec