Merge 907449bd99 into edf9e25001

* feat: support client verify for derp

* docs: fix doc for integration test

* tests: add integration test for DERP verify endpoint

* tests: use `tailcfg.DERPMap` instead of `[]byte`

* refactor: introduce func `ContainsNodeKey`

* tests(dsic): use string builder for cmd args

* ci: fix tests order

* tests: fix derper failure

* chore: cleanup

* tests(verify-client): perfer to use `CreateHeadscaleEnv`

* refactor(verify-client): simplify error handling

* tests: fix `TestDERPVerifyEndpoint`

* refactor: make `doVerify` a seperated func

---------

Co-authored-by: 117503445 <t117503445@gmail.com>

.github/workflows/test-integration.yaml

@@ -38,6 +38,7 @@ jobs:
           - TestNodeMoveCommand
           - TestPolicyCommand
           - TestPolicyBrokenConfigCommand
+          - TestDERPVerifyEndpoint
           - TestResolveMagicDNS
           - TestValidateResolvConf
           - TestDERPServerScenario

CHANGELOG.md

@@ -23,6 +23,7 @@
 - Added conversion of 'Hostname' to 'givenName' in a node with FQDN rules applied [#2198](https://github.com/juanfont/headscale/pull/2198)
 - Fixed updating of hostname and givenName when it is updated in HostInfo [#2199](https://github.com/juanfont/headscale/pull/2199)
 - Fixed missing `stable-debug` container tag [#2232](https://github.com/juanfont/headscale/pr/2232)
+- Loosened up `server_url` and `base_domain` check. It was overly strict in some cases.
 
 ## 0.23.0 (2024-09-18)
 

Dockerfile.derper

@@ -0,0 +1,19 @@
+# For testing purposes only
+
+FROM golang:alpine AS build-env
+
+WORKDIR /go/src
+
+RUN apk add --no-cache git
+ARG VERSION_BRANCH=main
+RUN git clone https://github.com/tailscale/tailscale.git --branch=$VERSION_BRANCH --depth=1
+WORKDIR /go/src/tailscale
+
+ARG TARGETARCH
+RUN GOARCH=$TARGETARCH go install -v ./cmd/derper
+
+FROM alpine:3.18
+RUN apk add --no-cache ca-certificates iptables iproute2 ip6tables curl
+
+COPY --from=build-env /go/bin/* /usr/local/bin/
+ENTRYPOINT [ "/usr/local/bin/derper" ]

Dockerfile.tailscale-HEAD

@@ -28,7 +28,9 @@ ARG VERSION_GIT_HASH=""
 ENV VERSION_GIT_HASH=$VERSION_GIT_HASH
 ARG TARGETARCH
 
-RUN GOARCH=$TARGETARCH go install -ldflags="\
+ARG BUILD_TAGS=""
+
+RUN GOARCH=$TARGETARCH go install -tags="${BUILD_TAGS}" -ldflags="\
       -X tailscale.com/version.longStamp=$VERSION_LONG \
       -X tailscale.com/version.shortStamp=$VERSION_SHORT \
       -X tailscale.com/version.gitCommitStamp=$VERSION_GIT_HASH" \

hscontrol/app.go

@@ -30,6 +30,7 @@ import (
 	"github.com/juanfont/headscale/hscontrol/mapper"
 	"github.com/juanfont/headscale/hscontrol/notifier"
 	"github.com/juanfont/headscale/hscontrol/policy"
+	"github.com/juanfont/headscale/hscontrol/policyv2"
 	"github.com/juanfont/headscale/hscontrol/types"
 	"github.com/juanfont/headscale/hscontrol/util"
 	zerolog "github.com/philip-bui/grpc-zerolog"
@@ -89,6 +90,7 @@ type Headscale struct {
 	DERPServer *derpServer.DERPServer
 
 	ACLPolicy     *policy.ACLPolicy
+	PolicyManager *policyv2.PolicyManager
 
 	mapper       *mapper.Mapper
 	nodeNotifier *notifier.Notifier
@@ -457,6 +459,8 @@ func (h *Headscale) createRouter(grpcMux *grpcRuntime.ServeMux) *mux.Router {
 	router.HandleFunc("/swagger/v1/openapiv2.json", headscale.SwaggerAPIv1).
 		Methods(http.MethodGet)
 
+	router.HandleFunc("/verify", h.VerifyHandler).Methods(http.MethodPost)
+
 	if h.cfg.DERP.ServerEnabled {
 		router.HandleFunc("/derp", h.DERPServer.DERPHandler)
 		router.HandleFunc("/derp/probe", derpServer.DERPProbeHandler)

hscontrol/handlers.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"net/http"
 	"strconv"
 	"strings"
@@ -56,6 +57,65 @@ func parseCabailityVersion(req *http.Request) (tailcfg.CapabilityVersion, error)
 	return tailcfg.CapabilityVersion(clientCapabilityVersion), nil
 }
 
+func (h *Headscale) handleVerifyRequest(
+	req *http.Request,
+) (bool, error) {
+	body, err := io.ReadAll(req.Body)
+	if err != nil {
+		return false, fmt.Errorf("cannot read request body: %w", err)
+	}
+
+	var derpAdmitClientRequest tailcfg.DERPAdmitClientRequest
+	if err := json.Unmarshal(body, &derpAdmitClientRequest); err != nil {
+		return false, fmt.Errorf("cannot parse derpAdmitClientRequest: %w", err)
+	}
+
+	nodes, err := h.db.ListNodes()
+	if err != nil {
+		return false, fmt.Errorf("cannot list nodes: %w", err)
+	}
+
+	return nodes.ContainsNodeKey(derpAdmitClientRequest.NodePublic), nil
+}
+
+// see https://github.com/tailscale/tailscale/blob/964282d34f06ecc06ce644769c66b0b31d118340/derp/derp_server.go#L1159, Derp use verifyClientsURL to verify whether a client is allowed to connect to the DERP server.
+func (h *Headscale) VerifyHandler(
+	writer http.ResponseWriter,
+	req *http.Request,
+) {
+	if req.Method != http.MethodPost {
+		http.Error(writer, "Wrong method", http.StatusMethodNotAllowed)
+
+		return
+	}
+	log.Debug().
+		Str("handler", "/verify").
+		Msg("verify client")
+
+	allow, err := h.handleVerifyRequest(req)
+	if err != nil {
+		log.Error().
+			Caller().
+			Err(err).
+			Msg("Failed to verify client")
+		http.Error(writer, "Internal error", http.StatusInternalServerError)
+	}
+
+	resp := tailcfg.DERPAdmitClientResponse{
+		Allow: allow,
+	}
+
+	writer.Header().Set("Content-Type", "application/json")
+	writer.WriteHeader(http.StatusOK)
+	err = json.NewEncoder(writer).Encode(resp)
+	if err != nil {
+		log.Error().
+			Caller().
+			Err(err).
+			Msg("Failed to write response")
+	}
+}
+
 // KeyHandler provides the Headscale pub key
 // Listens in /key.
 func (h *Headscale) KeyHandler(

hscontrol/policy/acls_test.go

@@ -1764,9 +1764,9 @@ var tsExitNodeDest = []tailcfg.NetPortRange{
 	},
 }
 
-// hsExitNodeDest is the list of destination IP ranges that are allowed when
+// hsExitNodeDestForTest is the list of destination IP ranges that are allowed when
 // we use headscale "autogroup:internet".
-var hsExitNodeDest = []tailcfg.NetPortRange{
+var hsExitNodeDestForTest = []tailcfg.NetPortRange{
 	{IP: "0.0.0.0/5", Ports: tailcfg.PortRangeAny},
 	{IP: "8.0.0.0/7", Ports: tailcfg.PortRangeAny},
 	{IP: "11.0.0.0/8", Ports: tailcfg.PortRangeAny},
@@ -1823,13 +1823,13 @@ func TestTheInternet(t *testing.T) {
 	internetPrefs := internetSet.Prefixes()
 
 	for i := range internetPrefs {
-		if internetPrefs[i].String() != hsExitNodeDest[i].IP {
-			t.Errorf("prefix from internet set %q != hsExit list %q", internetPrefs[i].String(), hsExitNodeDest[i].IP)
+		if internetPrefs[i].String() != hsExitNodeDestForTest[i].IP {
+			t.Errorf("prefix from internet set %q != hsExit list %q", internetPrefs[i].String(), hsExitNodeDestForTest[i].IP)
 		}
 	}
 
-	if len(internetPrefs) != len(hsExitNodeDest) {
-		t.Fatalf("expected same length of prefixes, internet: %d, hsExit: %d", len(internetPrefs), len(hsExitNodeDest))
+	if len(internetPrefs) != len(hsExitNodeDestForTest) {
+		t.Fatalf("expected same length of prefixes, internet: %d, hsExit: %d", len(internetPrefs), len(hsExitNodeDestForTest))
 	}
 }
 
@@ -1838,20 +1838,27 @@ func TestReduceFilterRules(t *testing.T) {
 		name  string
 		node  *types.Node
 		peers types.Nodes
-		pol   ACLPolicy
+		pol   string
 		want  []tailcfg.FilterRule
 	}{
 		{
 			name: "host1-can-reach-host2-no-rules",
-			pol: ACLPolicy{
-				ACLs: []ACL{
+			pol: `
+{
+  "acls": [
     {
-						Action:       "accept",
-						Sources:      []string{"100.64.0.1"},
-						Destinations: []string{"100.64.0.2:*"},
-					},
-				},
-			},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "100.64.0.1"
+      ],
+      "dst": [
+        "100.64.0.2:*"
+      ]
+    }
+  ],
+}
+`,
 			node: &types.Node{
 				IPv4: iap("100.64.0.1"),
 				IPv6: iap("fd7a:115c:a1e0:ab12:4843:2222:6273:2221"),
@@ -1868,23 +1875,37 @@ func TestReduceFilterRules(t *testing.T) {
 		},
 		{
 			name: "1604-subnet-routers-are-preserved",
-			pol: ACLPolicy{
-				Groups: Groups{
-					"group:admins": {"user1"},
+			pol: `
+{
+  "groups": {
+    "group:admins": [
+      "user1"
+    ]
   },
-				ACLs: []ACL{
+  "acls": [
     {
-						Action:       "accept",
-						Sources:      []string{"group:admins"},
-						Destinations: []string{"group:admins:*"},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:admins"
+      ],
+      "dst": [
+        "group:admins:*"
+      ]
     },
     {
-						Action:       "accept",
-						Sources:      []string{"group:admins"},
-						Destinations: []string{"10.33.0.0/16:*"},
-					},
-				},
-			},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:admins"
+      ],
+      "dst": [
+        "10.33.0.0/16:*"
+      ]
+    }
+  ],
+}
+`,
 			node: &types.Node{
 				IPv4: iap("100.64.0.1"),
 				IPv6: iap("fd7a:115c:a1e0::1"),
@@ -1939,31 +1960,42 @@ func TestReduceFilterRules(t *testing.T) {
 		},
 		{
 			name: "1786-reducing-breaks-exit-nodes-the-client",
-			pol: ACLPolicy{
-				Hosts: Hosts{
-					// Exit node
-					"internal": netip.MustParsePrefix("100.64.0.100/32"),
+			pol: `
+{
+  "groups": {
+    "group:team": [
+      "user3",
+      "user2",
+      "user1"
+    ]
   },
-				Groups: Groups{
-					"group:team": {"user3", "user2", "user1"},
+  "hosts": {
+    "internal": "100.64.0.100/32"
   },
-				ACLs: []ACL{
+  "acls": [
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
-							"internal:*",
-						},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
+        "internal:*"
+      ]
     },
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
-							"autogroup:internet:*",
-						},
-					},
-				},
-			},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
+        "autogroup:internet:*"
+      ]
+    }
+  ],
+}
+`,
 			node: &types.Node{
 				IPv4: iap("100.64.0.1"),
 				IPv6: iap("fd7a:115c:a1e0::1"),
@@ -1989,31 +2021,42 @@ func TestReduceFilterRules(t *testing.T) {
 		},
 		{
 			name: "1786-reducing-breaks-exit-nodes-the-exit",
-			pol: ACLPolicy{
-				Hosts: Hosts{
-					// Exit node
-					"internal": netip.MustParsePrefix("100.64.0.100/32"),
+			pol: `
+{
+  "groups": {
+    "group:team": [
+      "user3",
+      "user2",
+      "user1"
+    ]
   },
-				Groups: Groups{
-					"group:team": {"user3", "user2", "user1"},
+  "hosts": {
+    "internal": "100.64.0.100/32"
   },
-				ACLs: []ACL{
+  "acls": [
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
-							"internal:*",
-						},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
+        "internal:*"
+      ]
     },
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
-							"autogroup:internet:*",
-						},
-					},
-				},
-			},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
+        "autogroup:internet:*"
+      ]
+    }
+  ],
+}
+`,
 			node: &types.Node{
 				IPv4: iap("100.64.0.100"),
 				IPv6: iap("fd7a:115c:a1e0::100"),
@@ -2050,32 +2093,42 @@ func TestReduceFilterRules(t *testing.T) {
 				},
 				{
 					SrcIPs:   []string{"100.64.0.1/32", "100.64.0.2/32", "fd7a:115c:a1e0::1/128", "fd7a:115c:a1e0::2/128"},
-					DstPorts: hsExitNodeDest,
+					DstPorts: hsExitNodeDestForTest,
 				},
 			},
 		},
 		{
 			name: "1786-reducing-breaks-exit-nodes-the-example-from-issue",
-			pol: ACLPolicy{
-				Hosts: Hosts{
-					// Exit node
-					"internal": netip.MustParsePrefix("100.64.0.100/32"),
+			pol: `
+{
+  "groups": {
+    "group:team": [
+      "user3",
+      "user2",
+      "user1"
+    ]
   },
-				Groups: Groups{
-					"group:team": {"user3", "user2", "user1"},
+  "hosts": {
+    "internal": "100.64.0.100/32"
   },
-				ACLs: []ACL{
+  "acls": [
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
-							"internal:*",
-						},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
+        "internal:*"
+      ]
     },
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
         "0.0.0.0/5:*",
         "8.0.0.0/7:*",
         "11.0.0.0/8:*",
@@ -2105,11 +2158,12 @@ func TestReduceFilterRules(t *testing.T) {
         "194.0.0.0/7:*",
         "196.0.0.0/6:*",
         "200.0.0.0/5:*",
-							"208.0.0.0/4:*",
-						},
-					},
-				},
-			},
+        "208.0.0.0/4:*"
+      ]
+    }
+  ],
+}
+`,
 			node: &types.Node{
 				IPv4: iap("100.64.0.100"),
 				IPv6: iap("fd7a:115c:a1e0::100"),
@@ -2186,32 +2240,43 @@ func TestReduceFilterRules(t *testing.T) {
 		},
 		{
 			name: "1786-reducing-breaks-exit-nodes-app-connector-like",
-			pol: ACLPolicy{
-				Hosts: Hosts{
-					// Exit node
-					"internal": netip.MustParsePrefix("100.64.0.100/32"),
+			pol: `
+{
+  "groups": {
+    "group:team": [
+      "user3",
+      "user2",
+      "user1"
+    ]
   },
-				Groups: Groups{
-					"group:team": {"user3", "user2", "user1"},
+  "hosts": {
+    "internal": "100.64.0.100/32"
   },
-				ACLs: []ACL{
+  "acls": [
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
-							"internal:*",
-						},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
+        "internal:*"
+      ]
     },
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
         "8.0.0.0/8:*",
-							"16.0.0.0/8:*",
-						},
-					},
-				},
-			},
+        "16.0.0.0/8:*"
+      ]
+    }
+  ],
+}
+`,
 			node: &types.Node{
 				IPv4: iap("100.64.0.100"),
 				IPv6: iap("fd7a:115c:a1e0::100"),
@@ -2263,32 +2328,43 @@ func TestReduceFilterRules(t *testing.T) {
 		},
 		{
 			name: "1786-reducing-breaks-exit-nodes-app-connector-like2",
-			pol: ACLPolicy{
-				Hosts: Hosts{
-					// Exit node
-					"internal": netip.MustParsePrefix("100.64.0.100/32"),
+			pol: `
+{
+  "groups": {
+    "group:team": [
+      "user3",
+      "user2",
+      "user1"
+    ]
   },
-				Groups: Groups{
-					"group:team": {"user3", "user2", "user1"},
+  "hosts": {
+    "internal": "100.64.0.100/32"
   },
-				ACLs: []ACL{
+  "acls": [
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
-							"internal:*",
-						},
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
+        "internal:*"
+      ]
     },
     {
-						Action:  "accept",
-						Sources: []string{"group:team"},
-						Destinations: []string{
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:team"
+      ],
+      "dst": [
         "8.0.0.0/16:*",
-							"16.0.0.0/16:*",
-						},
-					},
-				},
-			},
+        "16.0.0.0/16:*"
+      ]
+    }
+  ],
+}
+`,
 			node: &types.Node{
 				IPv4: iap("100.64.0.100"),
 				IPv6: iap("fd7a:115c:a1e0::100"),
@@ -2340,25 +2416,32 @@ func TestReduceFilterRules(t *testing.T) {
 		},
 		{
 			name: "1817-reduce-breaks-32-mask",
-			pol: ACLPolicy{
-				Hosts: Hosts{
-					"vlan1": netip.MustParsePrefix("172.16.0.0/24"),
-					"dns1":  netip.MustParsePrefix("172.16.0.21/32"),
+			pol: `
+{
+  "groups": {
+    "group:access": [
+      "user1"
+    ]
   },
-				Groups: Groups{
-					"group:access": {"user1"},
+  "hosts": {
+    "dns1": "172.16.0.21/32",
+    "vlan1": "172.16.0.0/24"
   },
-				ACLs: []ACL{
+  "acls": [
     {
-						Action:  "accept",
-						Sources: []string{"group:access"},
-						Destinations: []string{
+      "action": "accept",
+      "proto": "",
+      "src": [
+        "group:access"
+      ],
+      "dst": [
         "tag:access-servers:*",
-							"dns1:*",
-						},
-					},
-				},
-			},
+        "dns1:*"
+      ]
+    }
+  ],
+}
+`,
 			node: &types.Node{
 				IPv4: iap("100.64.0.100"),
 				IPv6: iap("fd7a:115c:a1e0::100"),
@@ -2399,7 +2482,11 @@ func TestReduceFilterRules(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got, _ := tt.pol.CompileFilterRules(
+			pol, err := LoadACLPolicyFromBytes([]byte(tt.pol))
+			if err != nil {
+				t.Fatalf("parsing policy: %s", err)
+			}
+			got, _ := pol.CompileFilterRules(
 				append(tt.peers, tt.node),
 			)
 

hscontrol/policyv2/filter.go

@@ -0,0 +1,180 @@
+package policyv2
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/juanfont/headscale/hscontrol/types"
+	"go4.org/netipx"
+	"tailscale.com/tailcfg"
+)
+
+var (
+	ErrInvalidAction = errors.New("invalid action")
+)
+
+// CompileFilterRules takes a set of nodes and an ACLPolicy and generates a
+// set of Tailscale compatible FilterRules used to allow traffic on clients.
+func (pol *Policy) CompileFilterRules(
+	users types.Users,
+	nodes types.Nodes,
+) ([]tailcfg.FilterRule, error) {
+	if pol == nil {
+		return tailcfg.FilterAllowAll, nil
+	}
+
+	var rules []tailcfg.FilterRule
+
+	for _, acl := range pol.ACLs {
+		if acl.Action != "accept" {
+			return nil, ErrInvalidAction
+		}
+
+		srcIPs, err := acl.Sources.Resolve(pol, users, nodes)
+		if err != nil {
+			return nil, fmt.Errorf("resolving source ips: %w", err)
+		}
+
+		// TODO(kradalby): integrate type into schema
+		// TODO(kradalby): figure out the _ is wildcard stuff
+		protocols, _, err := parseProtocol(acl.Protocol)
+		if err != nil {
+			return nil, fmt.Errorf("parsing policy, protocol err: %w ", err)
+		}
+
+		var destPorts []tailcfg.NetPortRange
+		for _, dest := range acl.Destinations {
+			ips, err := dest.Alias.Resolve(pol, users, nodes)
+			if err != nil {
+				return nil, err
+			}
+
+			for _, pref := range ips.Prefixes() {
+				for _, port := range dest.Ports {
+					pr := tailcfg.NetPortRange{
+						IP:    pref.String(),
+						Ports: port,
+					}
+					destPorts = append(destPorts, pr)
+				}
+			}
+		}
+
+		rules = append(rules, tailcfg.FilterRule{
+			SrcIPs:   ipSetToPrefixStringList(srcIPs),
+			DstPorts: destPorts,
+			IPProto:  protocols,
+		})
+	}
+
+	return rules, nil
+}
+
+func sshAction(accept bool, duration time.Duration) tailcfg.SSHAction {
+	return tailcfg.SSHAction{
+		Reject:                   !accept,
+		Accept:                   accept,
+		SessionDuration:          duration,
+		AllowAgentForwarding:     true,
+		AllowLocalPortForwarding: true,
+	}
+}
+
+func (pol *Policy) CompileSSHPolicy(
+	users types.Users,
+	node types.Node,
+	nodes types.Nodes,
+) (*tailcfg.SSHPolicy, error) {
+	if pol == nil {
+		return nil, nil
+	}
+
+	var rules []*tailcfg.SSHRule
+
+	for index, rule := range pol.SSHs {
+		var dest netipx.IPSetBuilder
+		for _, src := range rule.Destinations {
+			ips, err := src.Resolve(pol, users, nodes)
+			if err != nil {
+				return nil, err
+			}
+			dest.AddSet(ips)
+		}
+
+		destSet, err := dest.IPSet()
+		if err != nil {
+			return nil, err
+		}
+
+		if !node.InIPSet(destSet) {
+			continue
+		}
+
+		var action tailcfg.SSHAction
+		switch rule.Action {
+		case "accept":
+			action = sshAction(true, 0)
+		case "check":
+			action = sshAction(true, rule.CheckPeriod)
+		default:
+			return nil, fmt.Errorf("parsing SSH policy, unknown action %q, index: %d: %w", rule.Action, index, err)
+		}
+
+		var principals []*tailcfg.SSHPrincipal
+		for _, src := range rule.Sources {
+			if isWildcard(rawSrc) {
+				principals = append(principals, &tailcfg.SSHPrincipal{
+					Any: true,
+				})
+			} else if isGroup(rawSrc) {
+				users, err := pol.expandUsersFromGroup(rawSrc)
+				if err != nil {
+					return nil, fmt.Errorf("parsing SSH policy, expanding user from group, index: %d->%d: %w", index, innerIndex, err)
+				}
+
+				for _, user := range users {
+					principals = append(principals, &tailcfg.SSHPrincipal{
+						UserLogin: user,
+					})
+				}
+			} else {
+				expandedSrcs, err := pol.ExpandAlias(
+					peers,
+					rawSrc,
+				)
+				if err != nil {
+					return nil, fmt.Errorf("parsing SSH policy, expanding alias, index: %d->%d: %w", index, innerIndex, err)
+				}
+				for _, expandedSrc := range expandedSrcs.Prefixes() {
+					principals = append(principals, &tailcfg.SSHPrincipal{
+						NodeIP: expandedSrc.Addr().String(),
+					})
+				}
+			}
+		}
+
+		userMap := make(map[string]string, len(rule.Users))
+		for _, user := range rule.Users {
+			userMap[user] = "="
+		}
+		rules = append(rules, &tailcfg.SSHRule{
+			Principals: principals,
+			SSHUsers:   userMap,
+			Action:     &action,
+		})
+	}
+
+	return &tailcfg.SSHPolicy{
+		Rules: rules,
+	}, nil
+}
+
+func ipSetToPrefixStringList(ips *netipx.IPSet) []string {
+	var out []string
+
+	for _, pref := range ips.Prefixes() {
+		out = append(out, pref.String())
+	}
+	return out
+}

hscontrol/policyv2/policy.go

@@ -0,0 +1,80 @@
+package policyv2
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/juanfont/headscale/hscontrol/types"
+	"tailscale.com/tailcfg"
+)
+
+type PolicyManager struct {
+	mu    sync.Mutex
+	pol   *Policy
+	users []types.User
+	nodes types.Nodes
+
+	filter []tailcfg.FilterRule
+
+	// TODO(kradalby): Implement SSH policy
+	sshPolicy *tailcfg.SSHPolicy
+}
+
+// NewPolicyManager creates a new PolicyManager from a policy file and a list of users and nodes.
+// It returns an error if the policy file is invalid.
+// The policy manager will update the filter rules based on the users and nodes.
+func NewPolicyManager(b []byte, users []types.User, nodes types.Nodes) (*PolicyManager, error) {
+	policy, err := policyFromBytes(b)
+	if err != nil {
+		return nil, fmt.Errorf("parsing policy: %w", err)
+	}
+
+	pm := PolicyManager{
+		pol:   policy,
+		users: users,
+		nodes: nodes,
+	}
+
+	err = pm.updateLocked()
+	if err != nil {
+		return nil, err
+	}
+
+	return &pm, nil
+}
+
+// Filter returns the current filter rules for the entire tailnet.
+func (pm *PolicyManager) Filter() []tailcfg.FilterRule {
+	pm.mu.Lock()
+	defer pm.mu.Unlock()
+	return pm.filter
+}
+
+// updateLocked updates the filter rules based on the current policy and nodes.
+// It must be called with the lock held.
+func (pm *PolicyManager) updateLocked() error {
+	filter, err := pm.pol.CompileFilterRules(pm.users, pm.nodes)
+	if err != nil {
+		return fmt.Errorf("compiling filter rules: %w", err)
+	}
+
+	pm.filter = filter
+
+	return nil
+}
+
+// SetUsers updates the users in the policy manager and updates the filter rules.
+func (pm *PolicyManager) SetUsers(users []types.User) error {
+	pm.mu.Lock()
+	defer pm.mu.Unlock()
+	pm.users = users
+	return pm.updateLocked()
+}
+
+// SetNodes updates the nodes in the policy manager and updates the filter rules.
+func (pm *PolicyManager) SetNodes(nodes types.Nodes) error {
+	pm.mu.Lock()
+	defer pm.mu.Unlock()
+	pm.nodes = nodes
+	return pm.updateLocked()
+}

hscontrol/policyv2/policy_test.go

@@ -0,0 +1,58 @@
+package policyv2
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/juanfont/headscale/hscontrol/types"
+	"github.com/stretchr/testify/require"
+	"gorm.io/gorm"
+	"tailscale.com/tailcfg"
+)
+
+func node(name, ipv4, ipv6 string, user types.User, hostinfo *tailcfg.Hostinfo) *types.Node {
+	return &types.Node{
+		ID:       0,
+		Hostname: name,
+		IPv4:     ap(ipv4),
+		IPv6:     ap(ipv6),
+		User:     user,
+		UserID:   user.ID,
+		Hostinfo: hostinfo,
+	}
+}
+
+func TestPolicyManager(t *testing.T) {
+	users := types.Users{
+		{Model: gorm.Model{ID: 1}, Name: "testuser", Email: "testuser@headscale.net"},
+		{Model: gorm.Model{ID: 2}, Name: "otheruser", Email: "otheruser@headscale.net"},
+	}
+
+	tests := []struct {
+		name       string
+		pol        string
+		nodes      types.Nodes
+		wantFilter []tailcfg.FilterRule
+	}{
+		{
+			name:       "empty-policy",
+			pol:        "{}",
+			nodes:      types.Nodes{},
+			wantFilter: nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pm, err := NewPolicyManager([]byte(tt.pol), users, tt.nodes)
+			require.NoError(t, err)
+
+			filter := pm.Filter()
+			if diff := cmp.Diff(filter, tt.wantFilter); diff != "" {
+				t.Errorf("Filter() mismatch (-want +got):\n%s", diff)
+			}
+
+			// TODO(kradalby): Test SSH Policy
+		})
+	}
+}

hscontrol/policyv2/types.go

@@ -0,0 +1,821 @@
+package policyv2
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/netip"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/juanfont/headscale/hscontrol/types"
+	"github.com/juanfont/headscale/hscontrol/util"
+	"github.com/tailscale/hujson"
+	"go4.org/netipx"
+	"tailscale.com/net/tsaddr"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/ptr"
+)
+
+var theInternetSet *netipx.IPSet
+
+// theInternet returns the IPSet for the Internet.
+// https://www.youtube.com/watch?v=iDbyYGrswtg
+func theInternet() *netipx.IPSet {
+	if theInternetSet != nil {
+		return theInternetSet
+	}
+
+	var internetBuilder netipx.IPSetBuilder
+	internetBuilder.AddPrefix(netip.MustParsePrefix("2000::/3"))
+	internetBuilder.AddPrefix(tsaddr.AllIPv4())
+
+	// Delete Private network addresses
+	// https://datatracker.ietf.org/doc/html/rfc1918
+	internetBuilder.RemovePrefix(netip.MustParsePrefix("fc00::/7"))
+	internetBuilder.RemovePrefix(netip.MustParsePrefix("10.0.0.0/8"))
+	internetBuilder.RemovePrefix(netip.MustParsePrefix("172.16.0.0/12"))
+	internetBuilder.RemovePrefix(netip.MustParsePrefix("192.168.0.0/16"))
+
+	// Delete Tailscale networks
+	internetBuilder.RemovePrefix(tsaddr.TailscaleULARange())
+	internetBuilder.RemovePrefix(tsaddr.CGNATRange())
+
+	// Delete "cant find DHCP networks"
+	internetBuilder.RemovePrefix(netip.MustParsePrefix("fe80::/10")) // link-loca
+	internetBuilder.RemovePrefix(netip.MustParsePrefix("169.254.0.0/16"))
+
+	theInternetSet, _ := internetBuilder.IPSet()
+	return theInternetSet
+}
+
+type Asterix int
+
+func (a Asterix) Validate() error {
+	return nil
+}
+
+func (a Asterix) String() string {
+	return "*"
+}
+
+func (a Asterix) UnmarshalJSON(b []byte) error {
+	return nil
+}
+
+func (a Asterix) Resolve(_ *Policy, _ types.Users, nodes types.Nodes) (*netipx.IPSet, error) {
+	var ips netipx.IPSetBuilder
+
+	ips.AddPrefix(tsaddr.AllIPv4())
+	ips.AddPrefix(tsaddr.AllIPv6())
+
+	return ips.IPSet()
+}
+
+// Username is a string that represents a username, it must contain an @.
+type Username string
+
+func (u Username) Validate() error {
+	if strings.Contains(string(u), "@") {
+		return nil
+	}
+	return fmt.Errorf("Username has to contain @, got: %q", u)
+}
+
+func (u *Username) String() string {
+	return string(*u)
+}
+
+func (u *Username) UnmarshalJSON(b []byte) error {
+	*u = Username(strings.Trim(string(b), `"`))
+	if err := u.Validate(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (u Username) CanBeTagOwner() bool {
+	return true
+}
+
+func (u Username) resolveUser(users types.Users) (*types.User, error) {
+	var potentialUsers types.Users
+	for _, user := range users {
+		if user.ProviderIdentifier == string(u) {
+			potentialUsers = append(potentialUsers, user)
+
+			break
+		}
+		if user.Email == string(u) {
+			potentialUsers = append(potentialUsers, user)
+		}
+		if user.Name == string(u) {
+			potentialUsers = append(potentialUsers, user)
+		}
+	}
+
+	if len(potentialUsers) > 1 {
+		return nil, fmt.Errorf("unable to resolve user identifier to distinct: %s matched multiple %s", u, potentialUsers)
+	} else if len(potentialUsers) == 0 {
+		return nil, fmt.Errorf("unable to resolve user identifier, no user found: %s not in %s", u, users)
+	}
+
+	user := potentialUsers[0]
+
+	return &user, nil
+}
+
+func (u Username) Resolve(_ *Policy, users types.Users, nodes types.Nodes) (*netipx.IPSet, error) {
+	var ips netipx.IPSetBuilder
+
+	user, err := u.resolveUser(users)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, node := range nodes {
+		if node.IsTagged() {
+			continue
+		}
+
+		if node.User.ID == user.ID {
+			node.AppendToIPSet(&ips)
+		}
+	}
+
+	return ips.IPSet()
+}
+
+// Group is a special string which is always prefixed with `group:`
+type Group string
+
+func (g Group) Validate() error {
+	if strings.HasPrefix(string(g), "group:") {
+		return nil
+	}
+	return fmt.Errorf(`Group has to start with "group:", got: %q`, g)
+}
+
+func (g *Group) UnmarshalJSON(b []byte) error {
+	*g = Group(strings.Trim(string(b), `"`))
+	if err := g.Validate(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (g Group) CanBeTagOwner() bool {
+	return true
+}
+
+func (g Group) Resolve(p *Policy, users types.Users, nodes types.Nodes) (*netipx.IPSet, error) {
+	var ips netipx.IPSetBuilder
+
+	for _, user := range p.Groups[g] {
+		uips, err := user.Resolve(nil, users, nodes)
+		if err != nil {
+			return nil, err
+		}
+
+		ips.AddSet(uips)
+	}
+
+	return ips.IPSet()
+}
+
+// Tag is a special string which is always prefixed with `tag:`
+type Tag string
+
+func (t Tag) Validate() error {
+	if strings.HasPrefix(string(t), "tag:") {
+		return nil
+	}
+	return fmt.Errorf(`tag has to start with "tag:", got: %q`, t)
+}
+
+func (t *Tag) UnmarshalJSON(b []byte) error {
+	*t = Tag(strings.Trim(string(b), `"`))
+	if err := t.Validate(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (t Tag) Resolve(p *Policy, _ types.Users, nodes types.Nodes) (*netipx.IPSet, error) {
+	var ips netipx.IPSetBuilder
+
+	for _, node := range nodes {
+		if node.HasTag(string(t)) {
+			node.AppendToIPSet(&ips)
+		}
+	}
+
+	return ips.IPSet()
+}
+
+// Host is a string that represents a hostname.
+type Host string
+
+func (h Host) Validate() error {
+	return nil
+}
+
+func (h *Host) UnmarshalJSON(b []byte) error {
+	*h = Host(strings.Trim(string(b), `"`))
+	if err := h.Validate(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (h Host) Resolve(p *Policy, _ types.Users, nodes types.Nodes) (*netipx.IPSet, error) {
+	var ips netipx.IPSetBuilder
+
+	pref, ok := p.Hosts[h]
+	if !ok {
+		return nil, fmt.Errorf("unable to resolve host: %q", h)
+	}
+	err := pref.Validate()
+	if err != nil {
+		return nil, err
+	}
+
+	// If the IP is a single host, look for a node to ensure we add all the IPs of
+	// the node to the IPSet.
+	appendIfNodeHasIP(nodes, &ips, pref)
+	ips.AddPrefix(netip.Prefix(pref))
+
+	return ips.IPSet()
+}
+
+func appendIfNodeHasIP(nodes types.Nodes, ips *netipx.IPSetBuilder, pref Prefix) {
+	if netip.Prefix(pref).IsSingleIP() {
+		addr := netip.Prefix(pref).Addr()
+		for _, node := range nodes {
+			if node.HasIP(addr) {
+				node.AppendToIPSet(ips)
+			}
+		}
+	}
+}
+
+type Prefix netip.Prefix
+
+func (p Prefix) Validate() error {
+	if !netip.Prefix(p).IsValid() {
+		return fmt.Errorf("Prefix %q is invalid", p)
+	}
+
+	return nil
+}
+
+func (p Prefix) String() string {
+	return netip.Prefix(p).String()
+}
+
+func (p *Prefix) parseString(addr string) error {
+	if !strings.Contains(addr, "/") {
+		addr, err := netip.ParseAddr(addr)
+		if err != nil {
+			return err
+		}
+		addrPref, err := addr.Prefix(addr.BitLen())
+		if err != nil {
+			return err
+		}
+
+		*p = Prefix(addrPref)
+		return nil
+	}
+
+	pref, err := netip.ParsePrefix(addr)
+	if err != nil {
+		return err
+	}
+	*p = Prefix(pref)
+	return nil
+}
+
+func (p *Prefix) UnmarshalJSON(b []byte) error {
+	err := p.parseString(strings.Trim(string(b), `"`))
+	if err != nil {
+		return err
+	}
+	if err := p.Validate(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (p Prefix) Resolve(_ *Policy, _ types.Users, nodes types.Nodes) (*netipx.IPSet, error) {
+	var ips netipx.IPSetBuilder
+
+	appendIfNodeHasIP(nodes, &ips, p)
+	ips.AddPrefix(netip.Prefix(p))
+
+	return ips.IPSet()
+}
+
+// AutoGroup is a special string which is always prefixed with `autogroup:`
+type AutoGroup string
+
+const (
+	AutoGroupInternet = "autogroup:internet"
+)
+
+var autogroups = []string{AutoGroupInternet}
+
+func (ag AutoGroup) Validate() error {
+	for _, valid := range autogroups {
+		if valid == string(ag) {
+			return nil
+		}
+	}
+
+	return fmt.Errorf("AutoGroup is invalid, got: %q, must be one of %v", ag, autogroups)
+}
+
+func (ag *AutoGroup) UnmarshalJSON(b []byte) error {
+	*ag = AutoGroup(strings.Trim(string(b), `"`))
+	if err := ag.Validate(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (ag AutoGroup) Resolve(_ *Policy, _ types.Users, _ types.Nodes) (*netipx.IPSet, error) {
+	switch ag {
+	case AutoGroupInternet:
+		return theInternet(), nil
+	}
+
+	return nil, nil
+}
+
+type Alias interface {
+	Validate() error
+	UnmarshalJSON([]byte) error
+	Resolve(*Policy, types.Users, types.Nodes) (*netipx.IPSet, error)
+}
+
+type AliasWithPorts struct {
+	Alias
+	Ports []tailcfg.PortRange
+}
+
+func (ve *AliasWithPorts) UnmarshalJSON(b []byte) error {
+	// TODO(kradalby): use encoding/json/v2 (go-json-experiment)
+	dec := json.NewDecoder(bytes.NewReader(b))
+	var v any
+	if err := dec.Decode(&v); err != nil {
+		return err
+	}
+
+	switch vs := v.(type) {
+	case string:
+		var portsPart string
+		var err error
+
+		if strings.Contains(vs, ":") {
+			vs, portsPart, err = splitDestination(vs)
+			if err != nil {
+				return err
+			}
+
+			ports, err := parsePorts(portsPart)
+			if err != nil {
+				return err
+			}
+			ve.Ports = ports
+		}
+
+		ve.Alias = parseAlias(vs)
+		if ve.Alias == nil {
+			return fmt.Errorf("could not determine the type of %q", vs)
+		}
+		if err := ve.Alias.Validate(); err != nil {
+			return err
+		}
+
+	default:
+		return fmt.Errorf("type %T not supported", vs)
+	}
+	return nil
+}
+
+func parseAlias(vs string) Alias {
+	// case netip.Addr:
+	// 	ve.Alias = Addr(val)
+	// case netip.Prefix:
+	// 	ve.Alias = Prefix(val)
+	var pref Prefix
+	err := pref.parseString(vs)
+	if err == nil {
+		return &pref
+	}
+
+	switch {
+	case vs == "*":
+		return Asterix(0)
+	case strings.Contains(vs, "@"):
+		return ptr.To(Username(vs))
+	case strings.HasPrefix(vs, "group:"):
+		return ptr.To(Group(vs))
+	case strings.HasPrefix(vs, "tag:"):
+		return ptr.To(Tag(vs))
+	case strings.HasPrefix(vs, "autogroup:"):
+		return ptr.To(AutoGroup(vs))
+	}
+
+	if !strings.Contains(vs, "@") && !strings.Contains(vs, ":") {
+		return ptr.To(Host(vs))
+	}
+
+	return nil
+}
+
+// AliasEnc is used to deserialize a Alias.
+type AliasEnc struct{ Alias }
+
+func (ve *AliasEnc) UnmarshalJSON(b []byte) error {
+	// TODO(kradalby): use encoding/json/v2 (go-json-experiment)
+	dec := json.NewDecoder(bytes.NewReader(b))
+	var v any
+	if err := dec.Decode(&v); err != nil {
+		return err
+	}
+	switch val := v.(type) {
+	case string:
+		ve.Alias = parseAlias(val)
+		if ve.Alias == nil {
+			return fmt.Errorf("could not determine the type of %q", val)
+		}
+		if err := ve.Alias.Validate(); err != nil {
+			return err
+		}
+	default:
+		return fmt.Errorf("type %T not supported", val)
+	}
+	return nil
+}
+
+type Aliases []Alias
+
+func (a *Aliases) UnmarshalJSON(b []byte) error {
+	var aliases []AliasEnc
+	err := json.Unmarshal(b, &aliases)
+	if err != nil {
+		return err
+	}
+
+	*a = make([]Alias, len(aliases))
+	for i, alias := range aliases {
+		(*a)[i] = alias.Alias
+	}
+	return nil
+}
+
+func (a Aliases) Resolve(p *Policy, users types.Users, nodes types.Nodes) (*netipx.IPSet, error) {
+	var ips netipx.IPSetBuilder
+
+	for _, alias := range a {
+		aips, err := alias.Resolve(p, users, nodes)
+		if err != nil {
+			return nil, err
+		}
+
+		ips.AddSet(aips)
+	}
+
+	return ips.IPSet()
+}
+
+type Owner interface {
+	CanBeTagOwner() bool
+	UnmarshalJSON([]byte) error
+}
+
+// OwnerEnc is used to deserialize a Owner.
+type OwnerEnc struct{ Owner }
+
+func (ve *OwnerEnc) UnmarshalJSON(b []byte) error {
+	// TODO(kradalby): use encoding/json/v2 (go-json-experiment)
+	dec := json.NewDecoder(bytes.NewReader(b))
+	var v any
+	if err := dec.Decode(&v); err != nil {
+		return err
+	}
+	switch val := v.(type) {
+	case string:
+
+		switch {
+		case strings.Contains(val, "@"):
+			ve.Owner = ptr.To(Username(val))
+		case strings.HasPrefix(val, "group:"):
+			ve.Owner = ptr.To(Group(val))
+		}
+	default:
+		return fmt.Errorf("type %T not supported", val)
+	}
+	return nil
+}
+
+type Owners []Owner
+
+func (o *Owners) UnmarshalJSON(b []byte) error {
+	var owners []OwnerEnc
+	err := json.Unmarshal(b, &owners)
+	if err != nil {
+		return err
+	}
+
+	*o = make([]Owner, len(owners))
+	for i, owner := range owners {
+		(*o)[i] = owner.Owner
+	}
+	return nil
+}
+
+type Usernames []Username
+
+// Groups are a map of Group to a list of Username.
+type Groups map[Group]Usernames
+
+// Hosts are alias for IP addresses or subnets.
+type Hosts map[Host]Prefix
+
+// TagOwners are a map of Tag to a list of the UserEntities that own the tag.
+type TagOwners map[Tag]Owners
+
+type AutoApprovers struct {
+	Routes   map[string][]string `json:"routes"`
+	ExitNode []string            `json:"exitNode"`
+}
+
+type ACL struct {
+	Action       string           `json:"action"`
+	Protocol     string           `json:"proto"`
+	Sources      Aliases          `json:"src"`
+	Destinations []AliasWithPorts `json:"dst"`
+}
+
+// Policy represents a Tailscale Network Policy.
+// TODO(kradalby):
+// Add validation method checking:
+// All users exists
+// All groups and users are valid tag TagOwners
+// Everything referred to in ACLs exists in other
+// entities.
+type Policy struct {
+	// validated is set if the policy has been validated.
+	// It is not safe to use before it is validated, and
+	// callers using it should panic if not
+	validated bool `json:"-"`
+
+	Groups        Groups        `json:"groups"`
+	Hosts         Hosts         `json:"hosts"`
+	TagOwners     TagOwners     `json:"tagOwners"`
+	ACLs          []ACL         `json:"acls"`
+	AutoApprovers AutoApprovers `json:"autoApprovers"`
+	SSHs          []SSH         `json:"ssh"`
+}
+
+// SSH controls who can ssh into which machines.
+type SSH struct {
+	Action       string        `json:"action"`
+	Sources      SSHSrcAliases `json:"src"`
+	Destinations SSHDstAliases `json:"dst"`
+	Users        []SSHUser     `json:"users"`
+	CheckPeriod  time.Duration `json:"checkPeriod,omitempty"`
+}
+
+// SSHSrcAliases is a list of aliases that can be used as sources in an SSH rule.
+// It can be a list of usernames, groups, tags or autogroups.
+type SSHSrcAliases []Alias
+
+func (a *SSHSrcAliases) UnmarshalJSON(b []byte) error {
+	var aliases []AliasEnc
+	err := json.Unmarshal(b, &aliases)
+	if err != nil {
+		return err
+	}
+
+	*a = make([]Alias, len(aliases))
+	for i, alias := range aliases {
+		switch alias.Alias.(type) {
+		case *Username, *Group, *Tag, *AutoGroup:
+			(*a)[i] = alias.Alias
+		default:
+			return fmt.Errorf("type %T not supported", alias.Alias)
+		}
+	}
+	return nil
+}
+
+// SSHDstAliases is a list of aliases that can be used as destinations in an SSH rule.
+// It can be a list of usernames, tags or autogroups.
+type SSHDstAliases []Alias
+
+func (a *SSHDstAliases) UnmarshalJSON(b []byte) error {
+	var aliases []AliasEnc
+	err := json.Unmarshal(b, &aliases)
+	if err != nil {
+		return err
+	}
+
+	*a = make([]Alias, len(aliases))
+	for i, alias := range aliases {
+		switch alias.Alias.(type) {
+		case *Username, *Tag, *AutoGroup:
+			(*a)[i] = alias.Alias
+		default:
+			return fmt.Errorf("type %T not supported", alias.Alias)
+		}
+	}
+	return nil
+}
+
+type SSHUser string
+
+func policyFromBytes(b []byte) (*Policy, error) {
+	var policy Policy
+	ast, err := hujson.Parse(b)
+	if err != nil {
+		return nil, fmt.Errorf("parsing HuJSON: %w", err)
+	}
+
+	ast.Standardize()
+	acl := ast.Pack()
+
+	err = json.Unmarshal(acl, &policy)
+	if err != nil {
+		return nil, fmt.Errorf("parsing policy from bytes: %w", err)
+	}
+
+	return &policy, nil
+}
+
+const (
+	expectedTokenItems = 2
+)
+
+// TODO(kradalby): copy tests from parseDestination in policy
+func splitDestination(dest string) (string, string, error) {
+	var tokens []string
+
+	// Check if there is a IPv4/6:Port combination, IPv6 has more than
+	// three ":".
+	tokens = strings.Split(dest, ":")
+	if len(tokens) < expectedTokenItems || len(tokens) > 3 {
+		port := tokens[len(tokens)-1]
+
+		maybeIPv6Str := strings.TrimSuffix(dest, ":"+port)
+
+		filteredMaybeIPv6Str := maybeIPv6Str
+		if strings.Contains(maybeIPv6Str, "/") {
+			networkParts := strings.Split(maybeIPv6Str, "/")
+			filteredMaybeIPv6Str = networkParts[0]
+		}
+
+		if maybeIPv6, err := netip.ParseAddr(filteredMaybeIPv6Str); err != nil && !maybeIPv6.Is6() {
+			return "", "", fmt.Errorf(
+				"failed to split destination: %v",
+				tokens,
+			)
+		} else {
+			tokens = []string{maybeIPv6Str, port}
+		}
+	}
+
+	var alias string
+	// We can have here stuff like:
+	// git-server:*
+	// 192.168.1.0/24:22
+	// fd7a:115c:a1e0::2:22
+	// fd7a:115c:a1e0::2/128:22
+	// tag:montreal-webserver:80,443
+	// tag:api-server:443
+	// example-host-1:*
+	if len(tokens) == expectedTokenItems {
+		alias = tokens[0]
+	} else {
+		alias = fmt.Sprintf("%s:%s", tokens[0], tokens[1])
+	}
+
+	return alias, tokens[len(tokens)-1], nil
+}
+
+// TODO(kradalby): write/copy tests from expandPorts in policy
+func parsePorts(portsStr string) ([]tailcfg.PortRange, error) {
+	if portsStr == "*" {
+		return []tailcfg.PortRange{
+			tailcfg.PortRangeAny,
+		}, nil
+	}
+
+	var ports []tailcfg.PortRange
+	for _, portStr := range strings.Split(portsStr, ",") {
+		rang := strings.Split(portStr, "-")
+		switch len(rang) {
+		case 1:
+			port, err := strconv.ParseUint(rang[0], util.Base10, util.BitSize16)
+			if err != nil {
+				return nil, err
+			}
+			ports = append(ports, tailcfg.PortRange{
+				First: uint16(port),
+				Last:  uint16(port),
+			})
+
+		case expectedTokenItems:
+			start, err := strconv.ParseUint(rang[0], util.Base10, util.BitSize16)
+			if err != nil {
+				return nil, err
+			}
+			last, err := strconv.ParseUint(rang[1], util.Base10, util.BitSize16)
+			if err != nil {
+				return nil, err
+			}
+			ports = append(ports, tailcfg.PortRange{
+				First: uint16(start),
+				Last:  uint16(last),
+			})
+
+		default:
+			return nil, errors.New("invalid ports")
+		}
+	}
+
+	return ports, nil
+}
+
+// For some reason golang.org/x/net/internal/iana is an internal package.
+const (
+	protocolICMP     = 1   // Internet Control Message
+	protocolIGMP     = 2   // Internet Group Management
+	protocolIPv4     = 4   // IPv4 encapsulation
+	protocolTCP      = 6   // Transmission Control
+	protocolEGP      = 8   // Exterior Gateway Protocol
+	protocolIGP      = 9   // any private interior gateway (used by Cisco for their IGRP)
+	protocolUDP      = 17  // User Datagram
+	protocolGRE      = 47  // Generic Routing Encapsulation
+	protocolESP      = 50  // Encap Security Payload
+	protocolAH       = 51  // Authentication Header
+	protocolIPv6ICMP = 58  // ICMP for IPv6
+	protocolSCTP     = 132 // Stream Control Transmission Protocol
+	ProtocolFC       = 133 // Fibre Channel
+)
+
+// parseProtocol reads the proto field of the ACL and generates a list of
+// protocols that will be allowed, following the IANA IP protocol number
+// https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml
+//
+// If the ACL proto field is empty, it allows ICMPv4, ICMPv6, TCP, and UDP,
+// as per Tailscale behaviour (see tailcfg.FilterRule).
+//
+// Also returns a boolean indicating if the protocol
+// requires all the destinations to use wildcard as port number (only TCP,
+// UDP and SCTP support specifying ports).
+func parseProtocol(protocol string) ([]int, bool, error) {
+	switch protocol {
+	case "":
+		return nil, false, nil
+	case "igmp":
+		return []int{protocolIGMP}, true, nil
+	case "ipv4", "ip-in-ip":
+		return []int{protocolIPv4}, true, nil
+	case "tcp":
+		return []int{protocolTCP}, false, nil
+	case "egp":
+		return []int{protocolEGP}, true, nil
+	case "igp":
+		return []int{protocolIGP}, true, nil
+	case "udp":
+		return []int{protocolUDP}, false, nil
+	case "gre":
+		return []int{protocolGRE}, true, nil
+	case "esp":
+		return []int{protocolESP}, true, nil
+	case "ah":
+		return []int{protocolAH}, true, nil
+	case "sctp":
+		return []int{protocolSCTP}, false, nil
+	case "icmp":
+		return []int{protocolICMP, protocolIPv6ICMP}, true, nil
+
+	default:
+		protocolNumber, err := strconv.Atoi(protocol)
+		if err != nil {
+			return nil, false, fmt.Errorf("parsing protocol number: %w", err)
+		}
+
+		// TODO(kradalby): What is this?
+		needsWildcard := protocolNumber != protocolTCP &&
+			protocolNumber != protocolUDP &&
+			protocolNumber != protocolSCTP
+
+		return []int{protocolNumber}, needsWildcard, nil
+	}
+}

hscontrol/policyv2/types_test.go

@@ -0,0 +1,555 @@
+package policyv2
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+	"github.com/juanfont/headscale/hscontrol/types"
+	"github.com/juanfont/headscale/hscontrol/util"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/ptr"
+)
+
+func TestUnmarshalPolicy(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		want    *Policy
+		wantErr string
+	}{
+		{
+			name:  "empty",
+			input: "{}",
+			want:  &Policy{},
+		},
+		{
+			name: "groups",
+			input: `
+{
+	"groups": {
+		"group:example": [
+			"derp@headscale.net",
+		],
+	},
+}
+`,
+			want: &Policy{
+				Groups: Groups{
+					Group("group:example"): []Username{Username("derp@headscale.net")},
+				},
+			},
+		},
+		{
+			name: "basic-types",
+			input: `
+{
+	"groups": {
+		"group:example": [
+			"testuser@headscale.net",
+		],
+		"group:other": [
+			"otheruser@headscale.net",
+		],
+	},
+
+	"tagOwners": {
+		"tag:user": ["testuser@headscale.net"],
+		"tag:group": ["group:other"],
+		"tag:userandgroup": ["testuser@headscale.net", "group:other"],
+	},
+
+	"hosts": {
+		"host-1": "100.100.100.100",
+		"subnet-1": "100.100.101.100/24",
+		"outside": "192.168.0.0/16",
+	},
+
+	"acls": [
+	    // All
+		{
+			"action": "accept",
+			"proto": "tcp",
+			"src": ["*"],
+			"dst": ["*:*"],
+		},
+		// Users
+		{
+			"action": "accept",
+			"proto": "tcp",
+			"src": ["testuser@headscale.net"],
+			"dst": ["otheruser@headscale.net:80"],
+		},
+		// Groups
+		{
+			"action": "accept",
+			"proto": "tcp",
+			"src": ["group:example"],
+			"dst": ["group:other:80"],
+		},
+		// Tailscale IP
+		{
+			"action": "accept",
+			"proto": "tcp",
+			"src": ["100.101.102.103"],
+			"dst": ["100.101.102.104:80"],
+		},
+		// Subnet
+		{
+			"action": "accept",
+			"proto": "udp",
+			"src": ["10.0.0.0/8"],
+			"dst": ["172.16.0.0/16:80"],
+		},
+		// Hosts
+		{
+			"action": "accept",
+			"proto": "tcp",
+			"src": ["subnet-1"],
+			"dst": ["host-1:80-88"],
+		},
+		// Tags
+		{
+			"action": "accept",
+			"proto": "tcp",
+			"src": ["tag:group"],
+			"dst": ["tag:user:80,443"],
+		},
+		// Autogroup
+		{
+			"action": "accept",
+			"proto": "tcp",
+			"src": ["tag:group"],
+			"dst": ["autogroup:internet:80"],
+		},
+	],
+}
+`,
+			want: &Policy{
+				Groups: Groups{
+					Group("group:example"): []Username{Username("testuser@headscale.net")},
+					Group("group:other"):   []Username{Username("otheruser@headscale.net")},
+				},
+				TagOwners: TagOwners{
+					Tag("tag:user"):         Owners{up("testuser@headscale.net")},
+					Tag("tag:group"):        Owners{gp("group:other")},
+					Tag("tag:userandgroup"): Owners{up("testuser@headscale.net"), gp("group:other")},
+				},
+				Hosts: Hosts{
+					"host-1":   Prefix(netip.MustParsePrefix("100.100.100.100/32")),
+					"subnet-1": Prefix(netip.MustParsePrefix("100.100.101.100/24")),
+					"outside":  Prefix(netip.MustParsePrefix("192.168.0.0/16")),
+				},
+				ACLs: []ACL{
+					{
+						Action:   "accept",
+						Protocol: "tcp",
+						Sources: Aliases{
+							// TODO(kradalby): Should this be host?
+							// It is:
+							// All traffic originating from Tailscale devices in your tailnet,
+							// any approved subnets and autogroup:shared.
+							// It does not allow traffic originating from
+							// non-tailscale devices (unless it is an approved route).
+							hp("*"),
+						},
+						Destinations: []AliasWithPorts{
+							{
+								// TODO(kradalby): Should this be host?
+								// It is:
+								// Includes any destination (no restrictions).
+								Alias: hp("*"),
+								Ports: []tailcfg.PortRange{tailcfg.PortRangeAny},
+							},
+						},
+					},
+					{
+						Action:   "accept",
+						Protocol: "tcp",
+						Sources: Aliases{
+							ptr.To(Username("testuser@headscale.net")),
+						},
+						Destinations: []AliasWithPorts{
+							{
+								Alias: ptr.To(Username("otheruser@headscale.net")),
+								Ports: []tailcfg.PortRange{{First: 80, Last: 80}},
+							},
+						},
+					},
+					{
+						Action:   "accept",
+						Protocol: "tcp",
+						Sources: Aliases{
+							gp("group:example"),
+						},
+						Destinations: []AliasWithPorts{
+							{
+								Alias: gp("group:other"),
+								Ports: []tailcfg.PortRange{{First: 80, Last: 80}},
+							},
+						},
+					},
+					{
+						Action:   "accept",
+						Protocol: "tcp",
+						Sources: Aliases{
+							pp("100.101.102.103/32"),
+						},
+						Destinations: []AliasWithPorts{
+							{
+								Alias: pp("100.101.102.104/32"),
+								Ports: []tailcfg.PortRange{{First: 80, Last: 80}},
+							},
+						},
+					},
+					{
+						Action:   "accept",
+						Protocol: "udp",
+						Sources: Aliases{
+							pp("10.0.0.0/8"),
+						},
+						Destinations: []AliasWithPorts{
+							{
+								Alias: pp("172.16.0.0/16"),
+								Ports: []tailcfg.PortRange{{First: 80, Last: 80}},
+							},
+						},
+					},
+					{
+						Action:   "accept",
+						Protocol: "tcp",
+						Sources: Aliases{
+							hp("subnet-1"),
+						},
+						Destinations: []AliasWithPorts{
+							{
+								Alias: hp("host-1"),
+								Ports: []tailcfg.PortRange{{First: 80, Last: 88}},
+							},
+						},
+					},
+					{
+						Action:   "accept",
+						Protocol: "tcp",
+						Sources: Aliases{
+							tp("tag:group"),
+						},
+						Destinations: []AliasWithPorts{
+							{
+								Alias: tp("tag:user"),
+								Ports: []tailcfg.PortRange{
+									{First: 80, Last: 80},
+									{First: 443, Last: 443},
+								},
+							},
+						},
+					},
+					{
+						Action:   "accept",
+						Protocol: "tcp",
+						Sources: Aliases{
+							tp("tag:group"),
+						},
+						Destinations: []AliasWithPorts{
+							{
+								Alias: agp("autogroup:internet"),
+								Ports: []tailcfg.PortRange{
+									{First: 80, Last: 80},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "invalid-username",
+			input: `
+{
+	"groups": {
+		"group:example": [
+			"valid@",
+			"invalid",
+		],
+	},
+}
+`,
+			wantErr: `Username has to contain @, got: "invalid"`,
+		},
+		{
+			name: "invalid-group",
+			input: `
+{
+	"groups": {
+		"grou:example": [
+			"valid@",
+		],
+	},
+}
+`,
+			wantErr: `Group has to start with "group:", got: "grou:example"`,
+		},
+		{
+			name: "group-in-group",
+			input: `
+{
+	"groups": {
+		"group:inner": [],
+		"group:example": [
+			"group:inner",
+		],
+	},
+}
+`,
+			wantErr: `Username has to contain @, got: "group:inner"`,
+		},
+		{
+			name: "invalid-prefix",
+			input: `
+{
+	"hosts": {
+		"derp": "10.0",
+	},
+}
+`,
+			wantErr: `ParseAddr("10.0"): IPv4 address too short`,
+		},
+		{
+			name: "invalid-auto-group",
+			input: `
+{
+	"acls": [
+		// Autogroup
+		{
+			"action": "accept",
+			"proto": "tcp",
+			"src": ["tag:group"],
+			"dst": ["autogroup:invalid:80"],
+		},
+	],
+}
+`,
+			wantErr: `AutoGroup is invalid, got: "autogroup:invalid", must be one of [autogroup:internet]`,
+		},
+	}
+
+	cmps := append(util.Comparers, cmp.Comparer(func(x, y Prefix) bool {
+		return x == y
+	}))
+	cmps = append(cmps, cmpopts.IgnoreUnexported(Policy{}))
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			policy, err := policyFromBytes([]byte(tt.input))
+			// TODO(kradalby): This error checking is broken,
+			// but so is my brain, #longflight
+			if err == nil {
+				if tt.wantErr == "" {
+					return
+				}
+				t.Fatalf("got success; wanted error %q", tt.wantErr)
+			}
+			if err.Error() != tt.wantErr {
+				t.Fatalf("got error %q; want %q", err, tt.wantErr)
+				// } else if err.Error() == tt.wantErr {
+				// 	return
+			}
+
+			if err != nil {
+				t.Fatalf("unexpected err: %q", err)
+			}
+
+			if diff := cmp.Diff(tt.want, &policy, cmps...); diff != "" {
+				t.Fatalf("unexpected policy (-want +got):\n%s", diff)
+			}
+		})
+	}
+}
+
+func gp(s string) *Group          { return ptr.To(Group(s)) }
+func up(s string) *Username       { return ptr.To(Username(s)) }
+func hp(s string) *Host           { return ptr.To(Host(s)) }
+func tp(s string) *Tag            { return ptr.To(Tag(s)) }
+func agp(s string) *AutoGroup     { return ptr.To(AutoGroup(s)) }
+func mp(pref string) netip.Prefix { return netip.MustParsePrefix(pref) }
+func ap(addr string) *netip.Addr  { return ptr.To(netip.MustParseAddr(addr)) }
+func pp(pref string) *Prefix      { return ptr.To(Prefix(netip.MustParsePrefix(pref))) }
+func p(pref string) Prefix        { return Prefix(netip.MustParsePrefix(pref)) }
+
+func TestResolvePolicy(t *testing.T) {
+	tests := []struct {
+		name      string
+		nodes     types.Nodes
+		pol       *Policy
+		toResolve Alias
+		want      []netip.Prefix
+	}{
+		{
+			name:      "prefix",
+			toResolve: pp("100.100.101.101/32"),
+			want:      []netip.Prefix{mp("100.100.101.101/32")},
+		},
+		{
+			name: "host",
+			pol: &Policy{
+				Hosts: Hosts{
+					"testhost": p("100.100.101.102/32"),
+				},
+			},
+			toResolve: hp("testhost"),
+			want:      []netip.Prefix{mp("100.100.101.102/32")},
+		},
+		{
+			name:      "username",
+			toResolve: ptr.To(Username("testuser")),
+			nodes: types.Nodes{
+				// Not matching other user
+				{
+					User: types.User{
+						Name: "notme",
+					},
+					IPv4: ap("100.100.101.1"),
+				},
+				// Not matching forced tags
+				{
+					User: types.User{
+						Name: "testuser",
+					},
+					ForcedTags: []string{"tag:anything"},
+					IPv4:       ap("100.100.101.2"),
+				},
+				// not matchin pak tag
+				{
+					User: types.User{
+						Name: "testuser",
+					},
+					AuthKey: &types.PreAuthKey{
+						Tags: []string{"alsotagged"},
+					},
+					IPv4: ap("100.100.101.3"),
+				},
+				{
+					User: types.User{
+						Name: "testuser",
+					},
+					IPv4: ap("100.100.101.103"),
+				},
+				{
+					User: types.User{
+						Name: "testuser",
+					},
+					IPv4: ap("100.100.101.104"),
+				},
+			},
+			want: []netip.Prefix{mp("100.100.101.103/32"), mp("100.100.101.104/32")},
+		},
+		{
+			name:      "group",
+			toResolve: ptr.To(Group("group:testgroup")),
+			nodes: types.Nodes{
+				// Not matching other user
+				{
+					User: types.User{
+						Name: "notmetoo",
+					},
+					IPv4: ap("100.100.101.4"),
+				},
+				// Not matching forced tags
+				{
+					User: types.User{
+						Name: "groupuser",
+					},
+					ForcedTags: []string{"tag:anything"},
+					IPv4:       ap("100.100.101.5"),
+				},
+				// not matchin pak tag
+				{
+					User: types.User{
+						Name: "groupuser",
+					},
+					AuthKey: &types.PreAuthKey{
+						Tags: []string{"tag:alsotagged"},
+					},
+					IPv4: ap("100.100.101.6"),
+				},
+				{
+					User: types.User{
+						Name: "groupuser",
+					},
+					IPv4: ap("100.100.101.203"),
+				},
+				{
+					User: types.User{
+						Name: "groupuser",
+					},
+					IPv4: ap("100.100.101.204"),
+				},
+			},
+			pol: &Policy{
+				Groups: Groups{
+					"group:testgroup":  Usernames{"groupuser"},
+					"group:othergroup": Usernames{"notmetoo"},
+				},
+			},
+			want: []netip.Prefix{mp("100.100.101.203/32"), mp("100.100.101.204/32")},
+		},
+		{
+			name:      "tag",
+			toResolve: tp("tag:test"),
+			nodes: types.Nodes{
+				// Not matching other user
+				{
+					User: types.User{
+						Name: "notmetoo",
+					},
+					IPv4: ap("100.100.101.9"),
+				},
+				// Not matching forced tags
+				{
+					ForcedTags: []string{"tag:anything"},
+					IPv4:       ap("100.100.101.10"),
+				},
+				// not matchin pak tag
+				{
+					AuthKey: &types.PreAuthKey{
+						Tags: []string{"tag:alsotagged"},
+					},
+					IPv4: ap("100.100.101.11"),
+				},
+				// Not matching forced tags
+				{
+					ForcedTags: []string{"tag:test"},
+					IPv4:       ap("100.100.101.234"),
+				},
+				// not matchin pak tag
+				{
+					AuthKey: &types.PreAuthKey{
+						Tags: []string{"tag:test"},
+					},
+					IPv4: ap("100.100.101.239"),
+				},
+			},
+			// TODO(kradalby): tests handling TagOwners + hostinfo
+			pol:  &Policy{},
+			want: []netip.Prefix{mp("100.100.101.234/32"), mp("100.100.101.239/32")},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ips, err := tt.toResolve.Resolve(tt.pol,
+				types.Users{},
+				tt.nodes)
+			if err != nil {
+				t.Fatalf("failed to resolve: %s", err)
+			}
+
+			prefs := ips.Prefixes()
+
+			if diff := cmp.Diff(tt.want, prefs, util.Comparers...); diff != "" {
+				t.Fatalf("unexpected prefs (-want +got):\n%s", diff)
+			}
+		})
+	}
+}

hscontrol/types/config.go

@@ -28,8 +28,9 @@ const (
 	maxDuration           time.Duration = 1<<63 - 1
 )
 
-var errOidcMutuallyExclusive = errors.New(
-	"oidc_client_secret and oidc_client_secret_path are mutually exclusive",
+var (
+	errOidcMutuallyExclusive = errors.New("oidc_client_secret and oidc_client_secret_path are mutually exclusive")
+	errServerURLSuffix       = errors.New("server_url cannot be part of base_domain in a way that could make the DERP and headscale server unreachable")
 )
 
 type IPAllocationStrategy string
@@ -827,11 +828,10 @@ func LoadServerConfig() (*Config, error) {
 	// - DERP run on their own domains
 	// - Control plane runs on login.tailscale.com/controlplane.tailscale.com
 	// - MagicDNS (BaseDomain) for users is on a *.ts.net domain per tailnet (e.g. tail-scale.ts.net)
-	if dnsConfig.BaseDomain != "" &&
-		strings.Contains(serverURL, dnsConfig.BaseDomain) {
-		return nil, errors.New(
-			"server_url cannot contain the base_domain, this will cause the headscale server and embedded DERP to become unreachable from the Tailscale node.",
-		)
+	if dnsConfig.BaseDomain != "" {
+		if err := isSafeServerURL(serverURL, dnsConfig.BaseDomain); err != nil {
+			return nil, err
+		}
 	}
 
 	return &Config{
@@ -924,6 +924,37 @@ func LoadServerConfig() (*Config, error) {
 	}, nil
 }
 
+// BaseDomain cannot be a suffix of the server URL.
+// This is because Tailscale takes over the domain in BaseDomain,
+// causing the headscale server and DERP to be unreachable.
+// For Tailscale upstream, the following is true:
+// - DERP run on their own domains.
+// - Control plane runs on login.tailscale.com/controlplane.tailscale.com.
+// - MagicDNS (BaseDomain) for users is on a *.ts.net domain per tailnet (e.g. tail-scale.ts.net).
+func isSafeServerURL(serverURL, baseDomain string) error {
+	server, err := url.Parse(serverURL)
+	if err != nil {
+		return err
+	}
+
+	serverDomainParts := strings.Split(server.Host, ".")
+	baseDomainParts := strings.Split(baseDomain, ".")
+
+	if len(serverDomainParts) <= len(baseDomainParts) {
+		return nil
+	}
+
+	s := len(serverDomainParts)
+	b := len(baseDomainParts)
+	for i := range len(baseDomainParts) {
+		if serverDomainParts[s-i-1] != baseDomainParts[b-i-1] {
+			return nil
+		}
+	}
+
+	return errServerURLSuffix
+}
+
 type deprecator struct {
 	warns  set.Set[string]
 	fatals set.Set[string]

hscontrol/types/config_test.go

@@ -1,6 +1,7 @@
 package types
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
@@ -139,7 +140,7 @@ func TestReadConfig(t *testing.T) {
 				return LoadServerConfig()
 			},
 			want:    nil,
-			wantErr: "server_url cannot contain the base_domain, this will cause the headscale server and embedded DERP to become unreachable from the Tailscale node.",
+			wantErr: errServerURLSuffix.Error(),
 		},
 		{
 			name:       "base-domain-not-in-server-url",
@@ -333,3 +334,64 @@ tls_letsencrypt_challenge_type: TLS-ALPN-01
 	err = LoadConfig(tmpDir, false)
 	assert.NoError(t, err)
 }
+
+// OK
+// server_url: headscale.com, base: clients.headscale.com
+// server_url: headscale.com, base: headscale.net
+//
+// NOT OK
+// server_url: server.headscale.com, base: headscale.com.
+func TestSafeServerURL(t *testing.T) {
+	tests := []struct {
+		serverURL, baseDomain,
+		wantErr string
+	}{
+		{
+			serverURL:  "https://example.com",
+			baseDomain: "example.org",
+		},
+		{
+			serverURL:  "https://headscale.com",
+			baseDomain: "headscale.com",
+		},
+		{
+			serverURL:  "https://headscale.com",
+			baseDomain: "clients.headscale.com",
+		},
+		{
+			serverURL:  "https://headscale.com",
+			baseDomain: "clients.subdomain.headscale.com",
+		},
+		{
+			serverURL:  "https://headscale.kristoffer.com",
+			baseDomain: "mybase",
+		},
+		{
+			serverURL:  "https://server.headscale.com",
+			baseDomain: "headscale.com",
+			wantErr:    errServerURLSuffix.Error(),
+		},
+		{
+			serverURL:  "https://server.subdomain.headscale.com",
+			baseDomain: "headscale.com",
+			wantErr:    errServerURLSuffix.Error(),
+		},
+		{
+			serverURL: "http://foo\x00",
+			wantErr:   `parse "http://foo\x00": net/url: invalid control character in URL`,
+		},
+	}
+
+	for _, tt := range tests {
+		testName := fmt.Sprintf("server=%s domain=%s", tt.serverURL, tt.baseDomain)
+		t.Run(testName, func(t *testing.T) {
+			err := isSafeServerURL(tt.serverURL, tt.baseDomain)
+			if tt.wantErr != "" {
+				assert.EqualError(t, err, tt.wantErr)
+
+				return
+			}
+			assert.NoError(t, err)
+		})
+	}
+}

hscontrol/types/node.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"net/netip"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -134,6 +135,60 @@ func (node *Node) IPs() []netip.Addr {
 	return ret
 }
 
+// HasIP reports if a node has a given IP address.
+func (node *Node) HasIP(i netip.Addr) bool {
+	for _, ip := range node.IPs() {
+		if ip.Compare(i) == 0 {
+			return true
+		}
+	}
+	return false
+}
+
+// IsTagged reports if a device is tagged
+// and therefore should not be treated as a
+// user owned device.
+// Currently, this function only handles tags set
+// via CLI ("forced tags" and preauthkeys)
+func (node *Node) IsTagged() bool {
+	if len(node.ForcedTags) > 0 {
+		return true
+	}
+
+	if node.AuthKey != nil && len(node.AuthKey.Tags) > 0 {
+		return true
+	}
+
+	if node.Hostinfo == nil {
+		return false
+	}
+
+	// TODO(kradalby): Figure out how tagging should work
+	// and hostinfo.requestedtags.
+	// Do this in other work.
+
+	return false
+}
+
+// HasTag reports if a node has a given tag.
+// Currently, this function only handles tags set
+// via CLI ("forced tags" and preauthkeys)
+func (node *Node) HasTag(tag string) bool {
+	if slices.Contains(node.ForcedTags, tag) {
+		return true
+	}
+
+	if node.AuthKey != nil && slices.Contains(node.AuthKey.Tags, tag) {
+		return true
+	}
+
+	// TODO(kradalby): Figure out how tagging should work
+	// and hostinfo.requestedtags.
+	// Do this in other work.
+
+	return false
+}
+
 func (node *Node) Prefixes() []netip.Prefix {
 	addrs := []netip.Prefix{}
 	for _, nodeAddress := range node.IPs() {
@@ -223,6 +278,16 @@ func (nodes Nodes) FilterByIP(ip netip.Addr) Nodes {
 	return found
 }
 
+func (nodes Nodes) ContainsNodeKey(nodeKey key.NodePublic) bool {
+	for _, node := range nodes {
+		if node.NodeKey == nodeKey {
+			return true
+		}
+	}
+
+	return false
+}
+
 func (node *Node) Proto() *v1.Node {
 	nodeProto := &v1.Node{
 		Id:         uint64(node.ID),

hscontrol/types/testdata/base-domain-in-server-url.yaml

@@ -8,7 +8,7 @@ prefixes:
 database:
   type: sqlite3
 
-server_url: "https://derp.no"
+server_url: "https://server.derp.no"
 
 dns:
   magic_dns: true

hscontrol/types/users.go

@@ -2,7 +2,9 @@ package types
 
 import (
 	"cmp"
+	"fmt"
 	"strconv"
+	"strings"
 
 	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
 	"github.com/juanfont/headscale/hscontrol/util"
@@ -13,6 +15,19 @@ import (
 
 type UserID uint64
 
+type Users []User
+
+func (u Users) String() string {
+	var sb strings.Builder
+	sb.WriteString("[ ")
+	for _, user := range u {
+		fmt.Fprintf(&sb, "%d: %s, ", user.ID, user.Name)
+	}
+	sb.WriteString(" ]")
+
+	return sb.String()
+}
+
 // User is the way Headscale implements the concept of users in Tailscale
 //
 // At the end of the day, users in Tailscale are some kind of 'bubbles' or users

integration/README.md

@@ -11,10 +11,10 @@ Tests are located in files ending with `_test.go` and the framework are located
 
 ## Running integration tests locally
 
-The easiest way to run tests locally is to use `[act](INSERT LINK)`, a local GitHub Actions runner:
+The easiest way to run tests locally is to use [act](https://github.com/nektos/act), a local GitHub Actions runner:
 
 ```
-act pull_request -W .github/workflows/test-integration-v2-TestPingAllByIP.yaml
+act pull_request -W .github/workflows/test-integration.yaml
 ```
 
 Alternatively, the `docker run` command in each GitHub workflow file can be used.

integration/derp_verify_endpoint_test.go

@@ -0,0 +1,96 @@
+package integration
+
+import (
+	"encoding/json"
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/juanfont/headscale/hscontrol/util"
+	"github.com/juanfont/headscale/integration/dsic"
+	"github.com/juanfont/headscale/integration/hsic"
+	"github.com/juanfont/headscale/integration/integrationutil"
+	"github.com/juanfont/headscale/integration/tsic"
+	"tailscale.com/tailcfg"
+)
+
+func TestDERPVerifyEndpoint(t *testing.T) {
+	IntegrationSkip(t)
+
+	// Generate random hostname for the headscale instance
+	hash, err := util.GenerateRandomStringDNSSafe(6)
+	assertNoErr(t, err)
+	testName := "derpverify"
+	hostname := fmt.Sprintf("hs-%s-%s", testName, hash)
+
+	headscalePort := 8080
+
+	// Create cert for headscale
+	certHeadscale, keyHeadscale, err := integrationutil.CreateCertificate(hostname)
+	assertNoErr(t, err)
+
+	scenario, err := NewScenario(dockertestMaxWait())
+	assertNoErr(t, err)
+	defer scenario.ShutdownAssertNoPanics(t)
+
+	spec := map[string]int{
+		"user1": len(MustTestVersions),
+	}
+
+	derper, err := scenario.CreateDERPServer("head",
+		dsic.WithCACert(certHeadscale),
+		dsic.WithVerifyClientURL(fmt.Sprintf("https://%s/verify", net.JoinHostPort(hostname, strconv.Itoa(headscalePort)))),
+	)
+	assertNoErr(t, err)
+
+	derpMap := tailcfg.DERPMap{
+		Regions: map[int]*tailcfg.DERPRegion{
+			900: {
+				RegionID:   900,
+				RegionCode: "test-derpverify",
+				RegionName: "TestDerpVerify",
+				Nodes: []*tailcfg.DERPNode{
+					{
+						Name:     "TestDerpVerify",
+						RegionID: 900,
+						HostName: derper.GetHostname(),
+						STUNPort: derper.GetSTUNPort(),
+						STUNOnly: false,
+						DERPPort: derper.GetDERPPort(),
+					},
+				},
+			},
+		},
+	}
+
+	err = scenario.CreateHeadscaleEnv(spec, []tsic.Option{tsic.WithCACert(derper.GetCert())},
+		hsic.WithHostname(hostname),
+		hsic.WithPort(headscalePort),
+		hsic.WithCustomTLS(certHeadscale, keyHeadscale),
+		hsic.WithHostnameAsServerURL(),
+		hsic.WithDERPConfig(derpMap))
+	assertNoErrHeadscaleEnv(t, err)
+
+	allClients, err := scenario.ListTailscaleClients()
+	assertNoErrListClients(t, err)
+
+	for _, client := range allClients {
+		report, err := client.DebugDERPRegion("test-derpverify")
+		assertNoErr(t, err)
+		successful := false
+		for _, line := range report.Info {
+			if strings.Contains(line, "Successfully established a DERP connection with node") {
+				successful = true
+
+				break
+			}
+		}
+		if !successful {
+			stJSON, err := json.Marshal(report)
+			assertNoErr(t, err)
+			t.Errorf("Client %s could not establish a DERP connection: %s", client.Hostname(), string(stJSON))
+		}
+	}
+}

integration/dsic/dsic.go

@@ -0,0 +1,321 @@
+package dsic
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/juanfont/headscale/hscontrol/util"
+	"github.com/juanfont/headscale/integration/dockertestutil"
+	"github.com/juanfont/headscale/integration/integrationutil"
+	"github.com/ory/dockertest/v3"
+	"github.com/ory/dockertest/v3/docker"
+)
+
+const (
+	dsicHashLength       = 6
+	dockerContextPath    = "../."
+	caCertRoot           = "/usr/local/share/ca-certificates"
+	DERPerCertRoot       = "/usr/local/share/derper-certs"
+	dockerExecuteTimeout = 60 * time.Second
+)
+
+var errDERPerStatusCodeNotOk = errors.New("DERPer status code not OK")
+
+// DERPServerInContainer represents DERP Server in Container (DSIC).
+type DERPServerInContainer struct {
+	version  string
+	hostname string
+
+	pool      *dockertest.Pool
+	container *dockertest.Resource
+	network   *dockertest.Network
+
+	stunPort            int
+	derpPort            int
+	caCerts             [][]byte
+	tlsCert             []byte
+	tlsKey              []byte
+	withExtraHosts      []string
+	withVerifyClientURL string
+	workdir             string
+}
+
+// Option represent optional settings that can be given to a
+// DERPer instance.
+type Option = func(c *DERPServerInContainer)
+
+// WithCACert adds it to the trusted surtificate of the Tailscale container.
+func WithCACert(cert []byte) Option {
+	return func(dsic *DERPServerInContainer) {
+		dsic.caCerts = append(dsic.caCerts, cert)
+	}
+}
+
+// WithOrCreateNetwork sets the Docker container network to use with
+// the DERPer instance, if the parameter is nil, a new network,
+// isolating the DERPer, will be created. If a network is
+// passed, the DERPer instance will join the given network.
+func WithOrCreateNetwork(network *dockertest.Network) Option {
+	return func(tsic *DERPServerInContainer) {
+		if network != nil {
+			tsic.network = network
+
+			return
+		}
+
+		network, err := dockertestutil.GetFirstOrCreateNetwork(
+			tsic.pool,
+			tsic.hostname+"-network",
+		)
+		if err != nil {
+			log.Fatalf("failed to create network: %s", err)
+		}
+
+		tsic.network = network
+	}
+}
+
+// WithDockerWorkdir allows the docker working directory to be set.
+func WithDockerWorkdir(dir string) Option {
+	return func(tsic *DERPServerInContainer) {
+		tsic.workdir = dir
+	}
+}
+
+// WithVerifyClientURL sets the URL to verify the client.
+func WithVerifyClientURL(url string) Option {
+	return func(tsic *DERPServerInContainer) {
+		tsic.withVerifyClientURL = url
+	}
+}
+
+// WithExtraHosts adds extra hosts to the container.
+func WithExtraHosts(hosts []string) Option {
+	return func(tsic *DERPServerInContainer) {
+		tsic.withExtraHosts = hosts
+	}
+}
+
+// New returns a new TailscaleInContainer instance.
+func New(
+	pool *dockertest.Pool,
+	version string,
+	network *dockertest.Network,
+	opts ...Option,
+) (*DERPServerInContainer, error) {
+	hash, err := util.GenerateRandomStringDNSSafe(dsicHashLength)
+	if err != nil {
+		return nil, err
+	}
+
+	hostname := fmt.Sprintf("derp-%s-%s", strings.ReplaceAll(version, ".", "-"), hash)
+	tlsCert, tlsKey, err := integrationutil.CreateCertificate(hostname)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create certificates for headscale test: %w", err)
+	}
+	dsic := &DERPServerInContainer{
+		version:  version,
+		hostname: hostname,
+		pool:     pool,
+		network:  network,
+		tlsCert:  tlsCert,
+		tlsKey:   tlsKey,
+		stunPort: 3478, //nolint
+		derpPort: 443,  //nolint
+	}
+
+	for _, opt := range opts {
+		opt(dsic)
+	}
+
+	var cmdArgs strings.Builder
+	fmt.Fprintf(&cmdArgs, "--hostname=%s", hostname)
+	fmt.Fprintf(&cmdArgs, " --certmode=manual")
+	fmt.Fprintf(&cmdArgs, " --certdir=%s", DERPerCertRoot)
+	fmt.Fprintf(&cmdArgs, " --a=:%d", dsic.derpPort)
+	fmt.Fprintf(&cmdArgs, " --stun=true")
+	fmt.Fprintf(&cmdArgs, " --stun-port=%d", dsic.stunPort)
+	if dsic.withVerifyClientURL != "" {
+		fmt.Fprintf(&cmdArgs, " --verify-client-url=%s", dsic.withVerifyClientURL)
+	}
+
+	runOptions := &dockertest.RunOptions{
+		Name:       hostname,
+		Networks:   []*dockertest.Network{dsic.network},
+		ExtraHosts: dsic.withExtraHosts,
+		// we currently need to give us some time to inject the certificate further down.
+		Entrypoint: []string{"/bin/sh", "-c", "/bin/sleep 3 ; update-ca-certificates ; derper " + cmdArgs.String()},
+		ExposedPorts: []string{
+			"80/tcp",
+			fmt.Sprintf("%d/tcp", dsic.derpPort),
+			fmt.Sprintf("%d/udp", dsic.stunPort),
+		},
+	}
+
+	if dsic.workdir != "" {
+		runOptions.WorkingDir = dsic.workdir
+	}
+
+	// dockertest isnt very good at handling containers that has already
+	// been created, this is an attempt to make sure this container isnt
+	// present.
+	err = pool.RemoveContainerByName(hostname)
+	if err != nil {
+		return nil, err
+	}
+
+	var container *dockertest.Resource
+	buildOptions := &dockertest.BuildOptions{
+		Dockerfile: "Dockerfile.derper",
+		ContextDir: dockerContextPath,
+		BuildArgs:  []docker.BuildArg{},
+	}
+	switch version {
+	case "head":
+		buildOptions.BuildArgs = append(buildOptions.BuildArgs, docker.BuildArg{
+			Name:  "VERSION_BRANCH",
+			Value: "main",
+		})
+	default:
+		buildOptions.BuildArgs = append(buildOptions.BuildArgs, docker.BuildArg{
+			Name:  "VERSION_BRANCH",
+			Value: "v" + version,
+		})
+	}
+	container, err = pool.BuildAndRunWithBuildOptions(
+		buildOptions,
+		runOptions,
+		dockertestutil.DockerRestartPolicy,
+		dockertestutil.DockerAllowLocalIPv6,
+		dockertestutil.DockerAllowNetworkAdministration,
+	)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"%s could not start tailscale DERPer container (version: %s): %w",
+			hostname,
+			version,
+			err,
+		)
+	}
+	log.Printf("Created %s container\n", hostname)
+
+	dsic.container = container
+
+	for i, cert := range dsic.caCerts {
+		err = dsic.WriteFile(fmt.Sprintf("%s/user-%d.crt", caCertRoot, i), cert)
+		if err != nil {
+			return nil, fmt.Errorf("failed to write TLS certificate to container: %w", err)
+		}
+	}
+	if len(dsic.tlsCert) != 0 {
+		err = dsic.WriteFile(fmt.Sprintf("%s/%s.crt", DERPerCertRoot, dsic.hostname), dsic.tlsCert)
+		if err != nil {
+			return nil, fmt.Errorf("failed to write TLS certificate to container: %w", err)
+		}
+	}
+	if len(dsic.tlsKey) != 0 {
+		err = dsic.WriteFile(fmt.Sprintf("%s/%s.key", DERPerCertRoot, dsic.hostname), dsic.tlsKey)
+		if err != nil {
+			return nil, fmt.Errorf("failed to write TLS key to container: %w", err)
+		}
+	}
+
+	return dsic, nil
+}
+
+// Shutdown stops and cleans up the DERPer container.
+func (t *DERPServerInContainer) Shutdown() error {
+	err := t.SaveLog("/tmp/control")
+	if err != nil {
+		log.Printf(
+			"Failed to save log from %s: %s",
+			t.hostname,
+			fmt.Errorf("failed to save log: %w", err),
+		)
+	}
+
+	return t.pool.Purge(t.container)
+}
+
+// GetCert returns the TLS certificate of the DERPer instance.
+func (t *DERPServerInContainer) GetCert() []byte {
+	return t.tlsCert
+}
+
+// Hostname returns the hostname of the DERPer instance.
+func (t *DERPServerInContainer) Hostname() string {
+	return t.hostname
+}
+
+// Version returns the running DERPer version of the instance.
+func (t *DERPServerInContainer) Version() string {
+	return t.version
+}
+
+// ID returns the Docker container ID of the DERPServerInContainer
+// instance.
+func (t *DERPServerInContainer) ID() string {
+	return t.container.Container.ID
+}
+
+func (t *DERPServerInContainer) GetHostname() string {
+	return t.hostname
+}
+
+// GetSTUNPort returns the STUN port of the DERPer instance.
+func (t *DERPServerInContainer) GetSTUNPort() int {
+	return t.stunPort
+}
+
+// GetDERPPort returns the DERP port of the DERPer instance.
+func (t *DERPServerInContainer) GetDERPPort() int {
+	return t.derpPort
+}
+
+// WaitForRunning blocks until the DERPer instance is ready to be used.
+func (t *DERPServerInContainer) WaitForRunning() error {
+	url := "https://" + net.JoinHostPort(t.GetHostname(), strconv.Itoa(t.GetDERPPort())) + "/"
+	log.Printf("waiting for DERPer to be ready at %s", url)
+
+	insecureTransport := http.DefaultTransport.(*http.Transport).Clone()      //nolint
+	insecureTransport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true} //nolint
+	client := &http.Client{Transport: insecureTransport}
+
+	return t.pool.Retry(func() error {
+		resp, err := client.Get(url) //nolint
+		if err != nil {
+			return fmt.Errorf("headscale is not ready: %w", err)
+		}
+
+		if resp.StatusCode != http.StatusOK {
+			return errDERPerStatusCodeNotOk
+		}
+
+		return nil
+	})
+}
+
+// ConnectToNetwork connects the DERPer instance to a network.
+func (t *DERPServerInContainer) ConnectToNetwork(network *dockertest.Network) error {
+	return t.container.ConnectToNetwork(network)
+}
+
+// WriteFile save file inside the container.
+func (t *DERPServerInContainer) WriteFile(path string, data []byte) error {
+	return integrationutil.WriteFileToContainer(t.pool, t.container, path, data)
+}
+
+// SaveLog saves the current stdout log of the container to a path
+// on the host system.
+func (t *DERPServerInContainer) SaveLog(path string) error {
+	_, _, err := dockertestutil.SaveLog(t.pool, t.container, path)
+
+	return err
+}

integration/embedded_derp_test.go

@@ -55,7 +55,7 @@ func TestDERPServerWebsocketScenario(t *testing.T) {
 	spec := map[string]ClientsSpec{
 		"user1": {
 			Plain:         0,
-			WebsocketDERP: len(MustTestVersions),
+			WebsocketDERP: 2,
 		},
 	}
 
@@ -239,10 +239,13 @@ func (s *EmbeddedDERPServerScenario) CreateHeadscaleEnv(
 
 		if clientCount.WebsocketDERP > 0 {
 			// Containers that use DERP-over-WebSocket
+			// Note that these clients *must* be built
+			// from source, which is currently
+			// only done for HEAD.
 			err = s.CreateTailscaleIsolatedNodesInUser(
 				hash,
 				userName,
-				"all",
+				tsic.VersionHead,
 				clientCount.WebsocketDERP,
 				tsic.WithWebsocketDERP(true),
 			)
@@ -307,7 +310,7 @@ func (s *EmbeddedDERPServerScenario) CreateTailscaleIsolatedNodesInUser(
 			cert := hsServer.GetCert()
 
 			opts = append(opts,
-				tsic.WithHeadscaleTLS(cert),
+				tsic.WithCACert(cert),
 			)
 
 			user.createWaitGroup.Go(func() error {

integration/hsic/hsic.go

@@ -1,19 +1,12 @@
 package hsic
 
 import (
-	"bytes"
-	"crypto/rand"
-	"crypto/rsa"
 	"crypto/tls"
-	"crypto/x509"
-	"crypto/x509/pkix"
 	"encoding/json"
-	"encoding/pem"
 	"errors"
 	"fmt"
 	"io"
 	"log"
-	"math/big"
 	"net"
 	"net/http"
 	"net/url"
@@ -32,11 +25,14 @@ import (
 	"github.com/juanfont/headscale/integration/integrationutil"
 	"github.com/ory/dockertest/v3"
 	"github.com/ory/dockertest/v3/docker"
+	"gopkg.in/yaml.v3"
+	"tailscale.com/tailcfg"
 )
 
 const (
 	hsicHashLength       = 6
 	dockerContextPath    = "../."
+	caCertRoot           = "/usr/local/share/ca-certificates"
 	aclPolicyPath        = "/etc/headscale/acl.hujson"
 	tlsCertPath          = "/etc/headscale/tls.cert"
 	tlsKeyPath           = "/etc/headscale/tls.key"
@@ -64,6 +60,7 @@ type HeadscaleInContainer struct {
 	// optional config
 	port             int
 	extraPorts       []string
+	caCerts          [][]byte
 	hostPortBindings map[string][]string
 	aclPolicy        *policy.ACLPolicy
 	env              map[string]string
@@ -88,18 +85,29 @@ func WithACLPolicy(acl *policy.ACLPolicy) Option {
 	}
 }
 
+// WithCACert adds it to the trusted surtificate of the container.
+func WithCACert(cert []byte) Option {
+	return func(hsic *HeadscaleInContainer) {
+		hsic.caCerts = append(hsic.caCerts, cert)
+	}
+}
+
 // WithTLS creates certificates and enables HTTPS.
 func WithTLS() Option {
 	return func(hsic *HeadscaleInContainer) {
-		cert, key, err := createCertificate(hsic.hostname)
+		cert, key, err := integrationutil.CreateCertificate(hsic.hostname)
 		if err != nil {
 			log.Fatalf("failed to create certificates for headscale test: %s", err)
 		}
 
-		// TODO(kradalby): Move somewhere appropriate
-		hsic.env["HEADSCALE_TLS_CERT_PATH"] = tlsCertPath
-		hsic.env["HEADSCALE_TLS_KEY_PATH"] = tlsKeyPath
+		hsic.tlsCert = cert
+		hsic.tlsKey = key
+	}
+}
 
+// WithCustomTLS uses the given certificates for the Headscale instance.
+func WithCustomTLS(cert, key []byte) Option {
+	return func(hsic *HeadscaleInContainer) {
 		hsic.tlsCert = cert
 		hsic.tlsKey = key
 	}
@@ -146,6 +154,13 @@ func WithTestName(testName string) Option {
 	}
 }
 
+// WithHostname sets the hostname of the Headscale instance.
+func WithHostname(hostname string) Option {
+	return func(hsic *HeadscaleInContainer) {
+		hsic.hostname = hostname
+	}
+}
+
 // WithHostnameAsServerURL sets the Headscale ServerURL based on
 // the Hostname.
 func WithHostnameAsServerURL() Option {
@@ -203,6 +218,34 @@ func WithEmbeddedDERPServerOnly() Option {
 	}
 }
 
+// WithDERPConfig configures Headscale use a custom
+// DERP server only.
+func WithDERPConfig(derpMap tailcfg.DERPMap) Option {
+	return func(hsic *HeadscaleInContainer) {
+		contents, err := yaml.Marshal(derpMap)
+		if err != nil {
+			log.Fatalf("failed to marshal DERP map: %s", err)
+
+			return
+		}
+
+		hsic.env["HEADSCALE_DERP_PATHS"] = "/etc/headscale/derp.yml"
+		hsic.filesInContainer = append(hsic.filesInContainer,
+			fileInContainer{
+				path:     "/etc/headscale/derp.yml",
+				contents: contents,
+			})
+
+		// Disable global DERP server and embedded DERP server
+		hsic.env["HEADSCALE_DERP_URLS"] = ""
+		hsic.env["HEADSCALE_DERP_SERVER_ENABLED"] = "false"
+
+		// Envknob for enabling DERP debug logs
+		hsic.env["DERP_DEBUG_LOGS"] = "true"
+		hsic.env["DERP_PROBER_DEBUG_LOGS"] = "true"
+	}
+}
+
 // WithTuning allows changing the tuning settings easily.
 func WithTuning(batchTimeout time.Duration, mapSessionChanSize int) Option {
 	return func(hsic *HeadscaleInContainer) {
@@ -300,6 +343,10 @@ func New(
 		"HEADSCALE_DEBUG_HIGH_CARDINALITY_METRICS=1",
 		"HEADSCALE_DEBUG_DUMP_CONFIG=1",
 	}
+	if hsic.hasTLS() {
+		hsic.env["HEADSCALE_TLS_CERT_PATH"] = tlsCertPath
+		hsic.env["HEADSCALE_TLS_KEY_PATH"] = tlsKeyPath
+	}
 	for key, value := range hsic.env {
 		env = append(env, fmt.Sprintf("%s=%s", key, value))
 	}
@@ -313,7 +360,7 @@ func New(
 		// Cmd:          []string{"headscale", "serve"},
 		// TODO(kradalby): Get rid of this hack, we currently need to give us some
 		// to inject the headscale configuration further down.
-		Entrypoint: []string{"/bin/bash", "-c", "/bin/sleep 3 ; headscale serve ; /bin/sleep 30"},
+		Entrypoint: []string{"/bin/bash", "-c", "/bin/sleep 3 ; update-ca-certificates ; headscale serve ; /bin/sleep 30"},
 		Env:        env,
 	}
 
@@ -351,6 +398,14 @@ func New(
 
 	hsic.container = container
 
+	// Write the CA certificates to the container
+	for i, cert := range hsic.caCerts {
+		err = hsic.WriteFile(fmt.Sprintf("%s/user-%d.crt", caCertRoot, i), cert)
+		if err != nil {
+			return nil, fmt.Errorf("failed to write TLS certificate to container: %w", err)
+		}
+	}
+
 	err = hsic.WriteFile("/etc/headscale/config.yaml", []byte(MinimumConfigYAML()))
 	if err != nil {
 		return nil, fmt.Errorf("failed to write headscale config to container: %w", err)
@@ -749,86 +804,3 @@ func (t *HeadscaleInContainer) SendInterrupt() error {
 
 	return nil
 }
-
-// nolint
-func createCertificate(hostname string) ([]byte, []byte, error) {
-	// From:
-	// https://shaneutt.com/blog/golang-ca-and-signed-cert-go/
-
-	ca := &x509.Certificate{
-		SerialNumber: big.NewInt(2019),
-		Subject: pkix.Name{
-			Organization: []string{"Headscale testing INC"},
-			Country:      []string{"NL"},
-			Locality:     []string{"Leiden"},
-		},
-		NotBefore: time.Now(),
-		NotAfter:  time.Now().Add(60 * time.Hour),
-		IsCA:      true,
-		ExtKeyUsage: []x509.ExtKeyUsage{
-			x509.ExtKeyUsageClientAuth,
-			x509.ExtKeyUsageServerAuth,
-		},
-		KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
-		BasicConstraintsValid: true,
-	}
-
-	caPrivKey, err := rsa.GenerateKey(rand.Reader, 4096)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	cert := &x509.Certificate{
-		SerialNumber: big.NewInt(1658),
-		Subject: pkix.Name{
-			CommonName:   hostname,
-			Organization: []string{"Headscale testing INC"},
-			Country:      []string{"NL"},
-			Locality:     []string{"Leiden"},
-		},
-		NotBefore:    time.Now(),
-		NotAfter:     time.Now().Add(60 * time.Minute),
-		SubjectKeyId: []byte{1, 2, 3, 4, 6},
-		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth},
-		KeyUsage:     x509.KeyUsageDigitalSignature,
-		DNSNames:     []string{hostname},
-	}
-
-	certPrivKey, err := rsa.GenerateKey(rand.Reader, 4096)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	certBytes, err := x509.CreateCertificate(
-		rand.Reader,
-		cert,
-		ca,
-		&certPrivKey.PublicKey,
-		caPrivKey,
-	)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	certPEM := new(bytes.Buffer)
-
-	err = pem.Encode(certPEM, &pem.Block{
-		Type:  "CERTIFICATE",
-		Bytes: certBytes,
-	})
-	if err != nil {
-		return nil, nil, err
-	}
-
-	certPrivKeyPEM := new(bytes.Buffer)
-
-	err = pem.Encode(certPrivKeyPEM, &pem.Block{
-		Type:  "RSA PRIVATE KEY",
-		Bytes: x509.MarshalPKCS1PrivateKey(certPrivKey),
-	})
-	if err != nil {
-		return nil, nil, err
-	}
-
-	return certPEM.Bytes(), certPrivKeyPEM.Bytes(), nil
-}

integration/integrationutil/util.go

@@ -3,9 +3,16 @@ package integrationutil
 import (
 	"archive/tar"
 	"bytes"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
 	"fmt"
 	"io"
+	"math/big"
 	"path/filepath"
+	"time"
 
 	"github.com/juanfont/headscale/integration/dockertestutil"
 	"github.com/ory/dockertest/v3"
@@ -93,3 +100,86 @@ func FetchPathFromContainer(
 
 	return buf.Bytes(), nil
 }
+
+// nolint
+func CreateCertificate(hostname string) ([]byte, []byte, error) {
+	// From:
+	// https://shaneutt.com/blog/golang-ca-and-signed-cert-go/
+
+	ca := &x509.Certificate{
+		SerialNumber: big.NewInt(2019),
+		Subject: pkix.Name{
+			Organization: []string{"Headscale testing INC"},
+			Country:      []string{"NL"},
+			Locality:     []string{"Leiden"},
+		},
+		NotBefore: time.Now(),
+		NotAfter:  time.Now().Add(60 * time.Hour),
+		IsCA:      true,
+		ExtKeyUsage: []x509.ExtKeyUsage{
+			x509.ExtKeyUsageClientAuth,
+			x509.ExtKeyUsageServerAuth,
+		},
+		KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
+		BasicConstraintsValid: true,
+	}
+
+	caPrivKey, err := rsa.GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	cert := &x509.Certificate{
+		SerialNumber: big.NewInt(1658),
+		Subject: pkix.Name{
+			CommonName:   hostname,
+			Organization: []string{"Headscale testing INC"},
+			Country:      []string{"NL"},
+			Locality:     []string{"Leiden"},
+		},
+		NotBefore:    time.Now(),
+		NotAfter:     time.Now().Add(60 * time.Minute),
+		SubjectKeyId: []byte{1, 2, 3, 4, 6},
+		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth},
+		KeyUsage:     x509.KeyUsageDigitalSignature,
+		DNSNames:     []string{hostname},
+	}
+
+	certPrivKey, err := rsa.GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	certBytes, err := x509.CreateCertificate(
+		rand.Reader,
+		cert,
+		ca,
+		&certPrivKey.PublicKey,
+		caPrivKey,
+	)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	certPEM := new(bytes.Buffer)
+
+	err = pem.Encode(certPEM, &pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: certBytes,
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	certPrivKeyPEM := new(bytes.Buffer)
+
+	err = pem.Encode(certPrivKeyPEM, &pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: x509.MarshalPKCS1PrivateKey(certPrivKey),
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return certPEM.Bytes(), certPrivKeyPEM.Bytes(), nil
+}

integration/scenario.go

@@ -14,6 +14,7 @@ import (
 	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
 	"github.com/juanfont/headscale/hscontrol/util"
 	"github.com/juanfont/headscale/integration/dockertestutil"
+	"github.com/juanfont/headscale/integration/dsic"
 	"github.com/juanfont/headscale/integration/hsic"
 	"github.com/juanfont/headscale/integration/tsic"
 	"github.com/ory/dockertest/v3"
@@ -140,6 +141,7 @@ type Scenario struct {
 	// TODO(kradalby): support multiple headcales for later, currently only
 	// use one.
 	controlServers *xsync.MapOf[string, ControlServer]
+	derpServers    []*dsic.DERPServerInContainer
 
 	users map[string]*User
 
@@ -224,6 +226,13 @@ func (s *Scenario) ShutdownAssertNoPanics(t *testing.T) {
 		}
 	}
 
+	for _, derp := range s.derpServers {
+		err := derp.Shutdown()
+		if err != nil {
+			log.Printf("failed to tear down derp server: %s", err)
+		}
+	}
+
 	if err := s.pool.RemoveNetwork(s.network); err != nil {
 		log.Printf("failed to remove network: %s", err)
 	}
@@ -352,7 +361,7 @@ func (s *Scenario) CreateTailscaleNodesInUser(
 			hostname := headscale.GetHostname()
 
 			opts = append(opts,
-				tsic.WithHeadscaleTLS(cert),
+				tsic.WithCACert(cert),
 				tsic.WithHeadscaleName(hostname),
 			)
 
@@ -651,3 +660,20 @@ func (s *Scenario) WaitForTailscaleLogout() error {
 
 	return nil
 }
+
+// CreateDERPServer creates a new DERP server in a container.
+func (s *Scenario) CreateDERPServer(version string, opts ...dsic.Option) (*dsic.DERPServerInContainer, error) {
+	derp, err := dsic.New(s.pool, version, s.network, opts...)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create DERP server: %w", err)
+	}
+
+	err = derp.WaitForRunning()
+	if err != nil {
+		return nil, fmt.Errorf("failed to reach DERP server: %w", err)
+	}
+
+	s.derpServers = append(s.derpServers, derp)
+
+	return derp, nil
+}

integration/tailscale.go

@@ -30,6 +30,7 @@ type TailscaleClient interface {
 	FQDN() (string, error)
 	Status(...bool) (*ipnstate.Status, error)
 	Netmap() (*netmap.NetworkMap, error)
+	DebugDERPRegion(region string) (*ipnstate.DebugDERPRegionReport, error)
 	Netcheck() (*netcheck.Report, error)
 	WaitForNeedsLogin() error
 	WaitForRunning() error

integration/tsic/tsic.go

@@ -12,6 +12,7 @@ import (
 	"net/netip"
 	"net/url"
 	"os"
+	"reflect"
 	"strconv"
 	"strings"
 	"time"
@@ -32,7 +33,7 @@ const (
 	defaultPingTimeout   = 300 * time.Millisecond
 	defaultPingCount     = 10
 	dockerContextPath    = "../."
-	headscaleCertPath    = "/usr/local/share/ca-certificates/headscale.crt"
+	caCertRoot           = "/usr/local/share/ca-certificates"
 	dockerExecuteTimeout = 60 * time.Second
 )
 
@@ -44,6 +45,11 @@ var (
 	errTailscaleCannotUpWithoutAuthkey = errors.New("cannot up without authkey")
 	errTailscaleNotConnected           = errors.New("tailscale not connected")
 	errTailscaledNotReadyForLogin      = errors.New("tailscaled not ready for login")
+	errInvalidClientConfig             = errors.New("verifiably invalid client config requested")
+)
+
+const (
+	VersionHead = "head"
 )
 
 func errTailscaleStatus(hostname string, err error) error {
@@ -65,7 +71,7 @@ type TailscaleInContainer struct {
 	fqdn string
 
 	// optional config
-	headscaleCert     []byte
+	caCerts           [][]byte
 	headscaleHostname string
 	withWebsocketDERP bool
 	withSSH           bool
@@ -74,17 +80,23 @@ type TailscaleInContainer struct {
 	withExtraHosts    []string
 	workdir           string
 	netfilter         string
+
+	// build options, solely for HEAD
+	buildConfig TailscaleInContainerBuildConfig
+}
+
+type TailscaleInContainerBuildConfig struct {
+	tags []string
 }
 
 // Option represent optional settings that can be given to a
 // Tailscale instance.
 type Option = func(c *TailscaleInContainer)
 
-// WithHeadscaleTLS takes the certificate of the Headscale instance
-// and adds it to the trusted surtificate of the Tailscale container.
-func WithHeadscaleTLS(cert []byte) Option {
+// WithCACert adds it to the trusted surtificate of the Tailscale container.
+func WithCACert(cert []byte) Option {
 	return func(tsic *TailscaleInContainer) {
-		tsic.headscaleCert = cert
+		tsic.caCerts = append(tsic.caCerts, cert)
 	}
 }
 
@@ -113,7 +125,7 @@ func WithOrCreateNetwork(network *dockertest.Network) Option {
 }
 
 // WithHeadscaleName set the name of the headscale instance,
-// mostly useful in combination with TLS and WithHeadscaleTLS.
+// mostly useful in combination with TLS and WithCACert.
 func WithHeadscaleName(hsName string) Option {
 	return func(tsic *TailscaleInContainer) {
 		tsic.headscaleHostname = hsName
@@ -175,6 +187,22 @@ func WithNetfilter(state string) Option {
 	}
 }
 
+// WithBuildTag adds an additional value to the `-tags=` parameter
+// of the Go compiler, allowing callers to customize the Tailscale client build.
+// This option is only meaningful when invoked on **HEAD** versions of the client.
+// Attempts to use it with any other version is a bug in the calling code.
+func WithBuildTag(tag string) Option {
+	return func(tsic *TailscaleInContainer) {
+		if tsic.version != VersionHead {
+			panic(errInvalidClientConfig)
+		}
+
+		tsic.buildConfig.tags = append(
+			tsic.buildConfig.tags, tag,
+		)
+	}
+}
+
 // New returns a new TailscaleInContainer instance.
 func New(
 	pool *dockertest.Pool,
@@ -219,18 +247,20 @@ func New(
 	}
 
 	if tsic.withWebsocketDERP {
+		if version != VersionHead {
+			return tsic, errInvalidClientConfig
+		}
+
+		WithBuildTag("ts_debug_websockets")(tsic)
+
 		tailscaleOptions.Env = append(
 			tailscaleOptions.Env,
 			fmt.Sprintf("TS_DEBUG_DERP_WS_CLIENT=%t", tsic.withWebsocketDERP),
 		)
 	}
 
-	if tsic.headscaleHostname != "" {
-		tailscaleOptions.ExtraHosts = []string{
-			"host.docker.internal:host-gateway",
-			fmt.Sprintf("%s:host-gateway", tsic.headscaleHostname),
-		}
-	}
+	tailscaleOptions.ExtraHosts = append(tailscaleOptions.ExtraHosts,
+		"host.docker.internal:host-gateway")
 
 	if tsic.workdir != "" {
 		tailscaleOptions.WorkingDir = tsic.workdir
@@ -245,14 +275,36 @@ func New(
 	}
 
 	var container *dockertest.Resource
+
+	if version != VersionHead {
+		// build options are not meaningful with pre-existing images,
+		// let's not lead anyone astray by pretending otherwise.
+		defaultBuildConfig := TailscaleInContainerBuildConfig{}
+		hasBuildConfig := !reflect.DeepEqual(defaultBuildConfig, tsic.buildConfig)
+		if hasBuildConfig {
+			return tsic, errInvalidClientConfig
+		}
+	}
+
 	switch version {
-	case "head":
+	case VersionHead:
 		buildOptions := &dockertest.BuildOptions{
 			Dockerfile: "Dockerfile.tailscale-HEAD",
 			ContextDir: dockerContextPath,
 			BuildArgs:  []docker.BuildArg{},
 		}
 
+		buildTags := strings.Join(tsic.buildConfig.tags, ",")
+		if len(buildTags) > 0 {
+			buildOptions.BuildArgs = append(
+				buildOptions.BuildArgs,
+				docker.BuildArg{
+					Name:  "BUILD_TAGS",
+					Value: buildTags,
+				},
+			)
+		}
+
 		container, err = pool.BuildAndRunWithBuildOptions(
 			buildOptions,
 			tailscaleOptions,
@@ -294,8 +346,8 @@ func New(
 
 	tsic.container = container
 
-	if tsic.hasTLS() {
-		err = tsic.WriteFile(headscaleCertPath, tsic.headscaleCert)
+	for i, cert := range tsic.caCerts {
+		err = tsic.WriteFile(fmt.Sprintf("%s/user-%d.crt", caCertRoot, i), cert)
 		if err != nil {
 			return nil, fmt.Errorf("failed to write TLS certificate to container: %w", err)
 		}
@@ -304,10 +356,6 @@ func New(
 	return tsic, nil
 }
 
-func (t *TailscaleInContainer) hasTLS() bool {
-	return len(t.headscaleCert) != 0
-}
-
 // Shutdown stops and cleans up the Tailscale container.
 func (t *TailscaleInContainer) Shutdown() error {
 	err := t.SaveLog("/tmp/control")
@@ -682,6 +730,34 @@ func (t *TailscaleInContainer) watchIPN(ctx context.Context) (*ipn.Notify, error
 	}
 }
 
+func (t *TailscaleInContainer) DebugDERPRegion(region string) (*ipnstate.DebugDERPRegionReport, error) {
+	if !util.TailscaleVersionNewerOrEqual("1.34", t.version) {
+		panic("tsic.DebugDERPRegion() called with unsupported version: " + t.version)
+	}
+
+	command := []string{
+		"tailscale",
+		"debug",
+		"derp",
+		region,
+	}
+
+	result, stderr, err := t.Execute(command)
+	if err != nil {
+		fmt.Printf("stderr: %s\n", stderr) // nolint
+
+		return nil, fmt.Errorf("failed to execute tailscale debug derp command: %w", err)
+	}
+
+	var report ipnstate.DebugDERPRegionReport
+	err = json.Unmarshal([]byte(result), &report)
+	if err != nil {
+		return nil, fmt.Errorf("failed to unmarshal tailscale derp region report: %w", err)
+	}
+
+	return &report, err
+}
+
 // Netcheck returns the current Netcheck Report (netcheck.Report) of the Tailscale instance.
 func (t *TailscaleInContainer) Netcheck() (*netcheck.Report, error) {
 	command := []string{