f16: CIDR-only bidirectional ACL — proves SaaS makes subnet routers
peers with CIDR-only rules and generates correct filter rules.
f18: CIDR + tag-based ACL — adds tag:ha ↔ tag:router rules.
Fix TestRoutesCompatReduceRoutes to pair src↔dst per-rule instead
of cross-product across all rules. Tag-based rules resolve to node
IPs in filter dests, not subnet CIDRs — a source in the tag rule
should only be tested against that rule's destinations.
Updates #3157
SaaS golden data (routes-ea* captures) proves that approved exit
routes appear in every peer's AllowedIPs. The previous commit
incorrectly dropped them based on a via-grant scenario where
exit routes were not approved.
TestRoutesCompatPeerAllowedIPs validates this against all captured
netmaps: peer AllowedIPs = node IPs + HA primary routes + exit
routes, filtered through ReduceRoutes.
Updates #3157
15 scenarios (ea1-ea15) covering exitNode field, routes map, both,
wrong tags, dual nodes, and baselines.
SaaS only approves exit routes via exitNode field. Exit routes in
the routes map are ignored for exit approval but still wildcard
subnet approval. Headscale already matches this behavior.
Remove IsExitRoute skip from TestRoutesCompatAutoApproval.
Updates #3157
Updates #3178
Rename all 594 test data files from .json to .hujson and add
descriptive header comments to each file documenting what policy
rules are under test and what outcome is expected.
Update test loaders in all 5 _test.go files to parse HuJSON via
hujson.Parse/Standardize/Pack before json.Unmarshal.
Add cross-dependency warning to via_compat_test.go documenting
that GRANT-V29/V30/V31/V36 are shared with TestGrantsCompat.
Add .gitignore exemption for testdata HuJSON files.
Remove unused error variables (ErrGrantViaNotSupported, ErrGrantEmptySources, ErrGrantEmptyDestinations, ErrGrantViaOnlyTag) and the stale TODO for via implementation. Update compat test skip reasons to reflect that user:*@passkey wildcard is a known unsupported feature, not a pending implementation.
Updates #2180
Remove TestGrantViaExitNodeSteering and TestGrantViaMixedSteering.
Exit node traffic forwarding through via grants cannot be validated
with curl/traceroute in Docker containers because Tailscale exit nodes
strip locally-connected subnets from their forwarding filter.
The correctness of via exit steering is validated by:
- Golden MapResponse comparison (TestViaGrantMapCompat with GRANT-V31
and GRANT-V36) comparing full netmap output against Tailscale SaaS
- Filter rule compatibility (TestGrantsCompat with GRANT-V14 through
GRANT-V36) comparing per-node PacketFilter rules against Tailscale SaaS
- TestGrantViaSubnetSteering (kept) validates via subnet steering with
actual curl/traceroute through Docker, which works for subnet routes
Updates #2180
Use per-node compilation path for via grants in BuildPeerMap and MatchersForNode to ensure via-granted nodes appear in peer maps. Fix ViaRoutesForPeer golden test route inference to correctly resolve via grant effects.
Updates #2180
Add golden test data for via exit route steering and fix via exit grant compilation to match Tailscale SaaS behavior. Includes MapResponse golden tests for via grant route steering verification.
Updates #2180
Via grants compile filter rules that depend on the node's route state
(SubnetRoutes, ExitRoutes). Without per-node compilation, these rules
were only included in the global filter path which explicitly skips via
grants (compileFilterRules skips grants with non-empty Via fields).
Add a needsPerNodeFilter flag that is true when the policy uses either
autogroup:self or via grants. filterForNodeLocked now uses this flag
instead of usesAutogroupSelf alone, ensuring via grant rules are
compiled per-node through compileFilterRulesForNode/compileViaGrant.
The filter cache also needs to account for route-dependent compilation:
- nodesHavePolicyAffectingChanges now treats route changes as
policy-affecting when needsPerNodeFilter is true, so SetNodes
triggers updateLocked and clears caches through the normal flow.
- invalidateGlobalPolicyCache now clears compiledFilterRulesMap
(the unreduced per-node cache) alongside filterRulesMap when
needsPerNodeFilter is true and routes changed.
Updates #2180
Add servertest grant policy control plane tests covering basic grants, via grants, and cap grants. Fix ReduceRoutes in State to apply route reduction to non-via routes first, then append via-included routes, preventing via grant routes from being incorrectly filtered.
Updates #2180
Test via route computation for viewer-peer pairs: self-steering returns
empty, viewer not in source returns empty, peer without advertised
destination returns empty, peer with/without via tag populates
Include/Exclude respectively, mixed prefix and autogroup:internet
destinations, and exit route steering.
7 subtests covering all code paths in ViaRoutesForPeer.
Updates #2180
Test companionCapGrantRules, sourcesHaveWildcard, sourcesHaveDangerAll,
srcIPsWithRoutes, the FilterAllowAll fix for grant-only policies,
compileViaGrant, compileGrantWithAutogroupSelf grant paths, and
destinationsToNetPortRange autogroup:internet skipping.
51 subtests across 8 test functions covering all grant-specific code
paths in filter.go that previously had no test coverage.
Updates #2180
compileFilterRules checked only pol.ACLs == nil to decide whether
to return FilterAllowAll (permit-any). Policies that use only Grants
(no ACLs) had nil ACLs, so the function short-circuited before
compiling any CapGrant rules. This meant cap/relay, cap/drive, and
any other App-based grant capabilities were silently ignored.
Check both ACLs and Grants are empty before returning FilterAllowAll.
Updates #2180
Via grants steer routes to specific nodes per viewer. Until now,
all clients saw the same routes for each peer because route
assembly was viewer-independent. This implements per-viewer route
visibility so that via-designated peers serve routes only to
matching viewers, while non-designated peers have those routes
withdrawn.
Add ViaRouteResult type (Include/Exclude prefix lists) and
ViaRoutesForPeer to the PolicyManager interface. The v2
implementation iterates via grants, resolves sources against the
viewer, matches destinations against the peer's advertised routes
(both subnet and exit), and categorizes prefixes by whether the
peer has the via tag.
Add RoutesForPeer to State which composes global primary election,
via Include/Exclude filtering, exit routes, and ACL reduction.
When no via grants exist, it falls back to existing behavior.
Update the mapper to call RoutesForPeer per-peer instead of using
a single route function for all peers. The route function now
returns all routes (subnet + exit), and TailNode filters exit
routes out of the PrimaryRoutes field for HA tracking.
Updates #2180
compileViaGrant only handled *Prefix destinations, skipping
*AutoGroup entirely. This meant via grants with
dst=[autogroup:internet] produced no filter rules even when the
node was an exit node with approved exit routes.
Switch the destination loop from a type assertion to a type switch
that handles both *Prefix (subnet routes) and *AutoGroup (exit
routes via autogroup:internet). Also check ExitRoutes() in
addition to SubnetRoutes() so the function doesn't bail early
when a node only has exit routes.
Updates #2180
Add autogroup:danger-all as a valid source alias that matches ALL IP
addresses including non-Tailscale addresses. When used as a source,
it resolves to 0.0.0.0/0 + ::/0 internally but produces SrcIPs: ["*"]
in filter rules. When used as a destination, it is rejected with an
error matching Tailscale SaaS behavior.
Key changes:
- Add AutoGroupDangerAll constant and validation
- Add sourcesHaveDangerAll() helper and hasDangerAll parameter to
srcIPsWithRoutes() across all compilation paths
- Add ErrAutogroupDangerAllDst for destination rejection
- Remove 3 AUTOGROUP_DANGER_ALL skip entries (K6, K7, K8)
Updates #2180
Implement comprehensive grant validation including: accept empty sources/destinations (they produce no rules), validate grant ip/app field requirements, capability name format, autogroup constraints, via tag existence, and default route CIDR restrictions.
Updates #2180
Compile grants with "via" field into FilterRules that are placed only
on nodes matching the via tag and actually advertising the destination
subnets. Key behavior:
- Filter rules go exclusively to via-nodes with matching approved routes
- Destination subnets not advertised by the via node are silently dropped
- App-only via grants (no ip field) produce no packet filter rules
- Via grants are skipped in the global compileFilterRules since they
are node-specific
Reduces grant compat test skips from 41 to 30 (11 newly passing).
Updates #2180
Compile grant app fields into CapGrant FilterRules matching Tailscale
SaaS behavior. Key changes:
- Generate CapGrant rules in compileFilterRules and
compileGrantWithAutogroupSelf, with node-specific /32 and /128
Dsts for autogroup:self grants
- Add reversed companion rules for drive→drive-sharer and
relay→relay-target capabilities, ordered by original cap name
- Narrow broad CapGrant Dsts to node-specific prefixes in
ReduceFilterRules via new reduceCapGrantRule helper
- Skip merging CapGrant rules in mergeFilterRules to preserve
per-capability structure
- Remove ip+app mutual exclusivity validation (Tailscale accepts both)
- Add semantic JSON comparison for RawMessage types and netip.Prefix
comparators in test infrastructure
Reduces grant compat test skips from 99 to 41 (58 newly passing).
Updates #2180
When an ACL source list contains a wildcard (*) alongside explicit
sources (tags, groups, hosts, etc.), Tailscale preserves the individual
IPs from non-wildcard sources in SrcIPs alongside the merged wildcard
CGNAT ranges. Previously, headscale's IPSetBuilder would merge all
sources into a single set, absorbing the explicit IPs into the wildcard
range.
Track non-wildcard resolved addresses separately during source
resolution, then append their individual IP strings to the output
when a wildcard is also present. This fixes the remaining 5 ACL
compat test failures (K01 and M06 subtests).
Updates #2180
When an ACL has non-autogroup destinations (groups, users, tags, hosts)
alongside autogroup:self, emit non-self grants before self grants to
match Tailscale's filter rule ordering. ACLs with only autogroup
destinations (self + member) preserve the policy-defined order.
This fixes ACL-A17, ACL-SF07, and ACL-SF11 compat test failures.
Updates #2180
Add exit route check in ReduceFilterRules to prevent exit nodes from receiving packet filter rules for destinations that only overlap via exit routes. Remove resolved SUBNET_ROUTE_FILTER_RULES grant skip entries and update error message formatting for grant validation.
Updates #2180
Per Tailscale documentation, the wildcard (*) source includes "any
approved subnets" — the actually-advertised-and-approved routes from
nodes, not the autoApprover policy prefixes.
Change Asterix.resolve() to return just the base CGNAT+ULA set, and
add approved subnet routes as separate SrcIPs entries in the filter
compilation path. This preserves individual route prefixes that would
otherwise be merged by IPSet (e.g., 10.0.0.0/8 absorbing 10.33.0.0/16).
Also swap rule ordering in compileGrantWithAutogroupSelf() to emit
non-self destination rules before autogroup:self rules, matching the
Tailscale FilterRule wire format ordering.
Remove the unused AutoApproverPolicy.prefixes() method.
Updates #2180
Add routable_ips and approved_routes fields to the node topology
definitions in all golden test files. These represent the subnet
routes actually advertised by nodes on the Tailscale SaaS network
during data capture:
Routes topology (92 files, 6 router nodes):
big-router: 10.0.0.0/8
subnet-router: 10.33.0.0/16
ha-router1: 192.168.1.0/24
ha-router2: 192.168.1.0/24
multi-router: 172.16.0.0/24
exit-node: 0.0.0.0/0, ::/0
ACL topology (199 files, 1 router node):
subnet-router: 10.33.0.0/16
Grants topology (203 files, 1 router node):
subnet-router: 10.33.0.0/16
The route assignments were deduced from the golden data by analyzing
which router nodes receive FilterRules for which destination CIDRs
across all test files, and cross-referenced with the MTS setup
script (setup_grant_nodes.sh).
Updates #2180
Use ip.String() instead of netip.PrefixFrom(ip, ip.BitLen()).String()
when building DstPorts for autogroup:self destinations. This produces
bare IPs like "100.90.199.68" instead of CIDR notation like
"100.90.199.68/32", matching the Tailscale FilterRule wire format.
Updates #2180
AppendToIPSet now adds both IPv4 and IPv6 addresses for nodes, matching Tailscale's FilterRule wire format where identity-based aliases (tags, users, groups, autogroups) resolve to both address families. Update ReduceFilterRules test expectations to include IPv6 entries.
Updates #2180
Replace 8,286 lines of inline Go test expectations with 92 JSON golden files captured from Tailscale SaaS. The data-driven test driver validates route filtering, auto-approval, HA routing, and exit node behavior against real Tailscale output.
Updates #2180
Replace 9,937 lines of inline Go test expectations with 215 JSON golden files captured from Tailscale SaaS. The new data-driven test driver compares headscale's filter compilation output against real Tailscale behavior for each node in an 8-node topology.
Updates #2180
Introduce ResolvedAddresses type for structured IP set results. Refactor all Alias.Resolve() methods to return ResolvedAddresses instead of raw IPSets. Restrict identity-based aliases to matching address families, fix nil dereferences in partial resolution paths, and update test expectations for the new IP format (bare IPs, IP ranges instead of CIDR prefixes).
Updates #2180
Rename tailscale_compat_test.go to tailscale_acl_compat_test.go to make room for the grants compat test. Add 237 GRANT-*.json golden test files captured from Tailscale SaaS and a data-driven test driver that compares headscale's grant filter compilation against real Tailscale behavior.
Updates #2180
Add support for the Grant policy format as an alternative to ACL format,
following Tailscale's policy v2 specification. Grants provide a more
structured way to define network access rules with explicit separation
of IP-based and capability-based permissions.
Key changes:
- Add Grant struct with Sources, Destinations, InternetProtocols (ip),
and App (capabilities) fields
- Add ProtocolPort type for unmarshaling protocol:port strings
- Add Grant validation in Policy.validate() to enforce:
- Mutual exclusivity of ip and app fields
- Required ip or app field presence
- Non-empty sources and destinations
- Refactor compileFilterRules to support both ACLs and Grants
- Convert ACLs to Grants internally via aclToGrants() for unified
processing
- Extract destinationsToNetPortRange() helper for cleaner code
- Rename parseProtocol() to toIANAProtocolNumbers() for clarity
- Add ProtocolNumberToName mapping for reverse lookups
The Grant format allows policies to be written using either the legacy
ACL format or the new Grant format. ACLs are converted to Grants
internally, ensuring backward compatibility while enabling the new
format's benefits.
Updates #2180
Kristoffer Dalby
Ubuntu
Kristoffer Dalby