register tailscale+udp network for HTTP3

Updates #33

Signed-off-by: Will Norris <will@tailscale.com>

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/caddyserver/caddy/v2 v2.8.4
 	github.com/google/go-cmp v0.6.0
 	go.uber.org/zap v1.27.0
-	tailscale.com v1.67.0-pre.0.20240510224123-fc1ae97e1037
+	tailscale.com v1.67.0-pre.0.20240602160856-30bd3ffdd3e8
 )
 
 require (
@@ -110,6 +110,7 @@ require (
 	github.com/pierrec/lz4/v4 v4.1.21 // indirect
 	github.com/pires/go-proxyproto v0.7.0 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
+	github.com/prometheus-community/pro-bing v0.4.0 // indirect
 	github.com/prometheus/client_golang v1.19.1 // indirect
 	github.com/prometheus/client_model v0.5.0 // indirect
 	github.com/prometheus/common v0.48.0 // indirect

go.sum

@@ -393,6 +393,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prashantv/gostub v1.1.0 h1:BTyx3RfQjRHnUWaGF9oQos79AlQ5k8WNktv7VGvVH4g=
 github.com/prashantv/gostub v1.1.0/go.mod h1:A5zLQHz7ieHGG7is6LLXLz7I8+3LZzsrV0P1IAHhP5U=
+github.com/prometheus-community/pro-bing v0.4.0 h1:YMbv+i08gQz97OZZBwLyvmmQEEzyfyrrjEaAchdy3R4=
+github.com/prometheus-community/pro-bing v0.4.0/go.mod h1:b7wRYZtCcPmt4Sz319BykUU241rWLe1VFXyiyWK/dH4=
 github.com/prometheus/client_golang v1.19.1 h1:wZWJDwK+NameRJuPGDhlnFgx8e8HN3XHQeLaYJFJBOE=
 github.com/prometheus/client_golang v1.19.1/go.mod h1:mP78NwGzrVks5S2H6ab8+ZZGJLZUq1hoULYBAYBw1Ho=
 github.com/prometheus/client_model v0.5.0 h1:VQw1hfvPvk3Uv6Qf29VrPF32JB6rtbgI6cYPYQjL0Qw=
@@ -748,5 +750,5 @@ nhooyr.io/websocket v1.8.10 h1:mv4p+MnGrLDcPlBoWsvPP7XCzTYMXP9F9eIGoKbgx7Q=
 nhooyr.io/websocket v1.8.10/go.mod h1:rN9OFWIUwuxg4fR5tELlYC04bXYowCP9GX47ivo2l+c=
 software.sslmate.com/src/go-pkcs12 v0.4.0 h1:H2g08FrTvSFKUj+D309j1DPfk5APnIdAQAB8aEykJ5k=
 software.sslmate.com/src/go-pkcs12 v0.4.0/go.mod h1:Qiz0EyvDRJjjxGyUQa2cCNZn/wMyzrRJ/qcDXOQazLI=
-tailscale.com v1.67.0-pre.0.20240510224123-fc1ae97e1037 h1:ZrUO++qvsCa1jRyg5QI2mrEY3/LgEg4UETvYwgFAIYw=
-tailscale.com v1.67.0-pre.0.20240510224123-fc1ae97e1037/go.mod h1:99BIV4U3UPw36Sva04xK2ZsEpVRUkY9jCdEDSAhaNGM=
+tailscale.com v1.67.0-pre.0.20240602160856-30bd3ffdd3e8 h1:XnIXLknCk4pIgFA/3iddz9D9nN7UiC4FTRIOmQ/+nRI=
+tailscale.com v1.67.0-pre.0.20240602160856-30bd3ffdd3e8/go.mod h1:fI1Vx71PB5JSJv93FKNSmdD0X5QnBuGllLk67AmeNRo=

module.go

@@ -9,21 +9,26 @@ import (
 	"crypto/tls"
 	"fmt"
 	"net"
+	"net/netip"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 
 	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
 	"go.uber.org/zap"
 	"tailscale.com/tsnet"
 )
 
 func init() {
-	caddy.RegisterNetwork("tailscale", getPlainListener)
+	caddy.RegisterNetwork("tailscale", getTCPListener)
 	caddy.RegisterNetwork("tailscale+tls", getTLSListener)
+	caddy.RegisterNetwork("tailscale+udp", getUDPListener)
+	caddyhttp.RegisterNetworkHTTP3("tailscale", "tailscale+udp")
 }
 
-func getPlainListener(c context.Context, _ string, addr string, _ net.ListenConfig) (any, error) {
+func getTCPListener(c context.Context, _ string, addr string, _ net.ListenConfig) (any, error) {
 	ctx, ok := c.(caddy.Context)
 	if !ok {
 		return nil, fmt.Errorf("context is not a caddy.Context: %T", c)
@@ -78,6 +83,43 @@ func getTLSListener(c context.Context, _ string, addr string, _ net.ListenConfig
 	return ln, nil
 }
 
+func getUDPListener(c context.Context, _ string, addr string, _ net.ListenConfig) (any, error) {
+	ctx, ok := c.(caddy.Context)
+	if !ok {
+		return nil, fmt.Errorf("context is not a caddy.Context: %T", c)
+	}
+
+	network, host, port, err := caddy.SplitNetworkAddress(addr)
+	if err != nil {
+		return nil, err
+	}
+
+	s, err := getNode(ctx, host)
+	if err != nil {
+		return nil, err
+	}
+
+	st, err := s.Up(context.Background())
+	if err != nil {
+		return nil, err
+	}
+
+	if network == "" {
+		network = "udp4"
+
+	}
+	var ap netip.AddrPort
+	for _, ip := range st.TailscaleIPs {
+		// TODO(will): watch for Tailscale IP changes and update listener
+		if (network == "udp4" && ip.Is4()) || (network == "udp6" && ip.Is6()) {
+			p, _ := strconv.Atoi(port)
+			ap = netip.AddrPortFrom(ip, uint16(p))
+			break
+		}
+	}
+	return s.Server.ListenPacket(network, ap.String())
+}
+
 // nodes are the Tailscale nodes that have been configured and started.
 // Node configuration comes from the global Tailscale Caddy app.
 // When nodes are no longer in used (e.g. all listeners have been closed), they are shutdown.