Merge remote-tracking branch 'origin/main' into benvin/nft-decodable

# Conflicts:
#	internal/nftables/compiler_test.go

internal/config/config_test.go

@@ -473,6 +473,20 @@ func TestValidateHosts(t *testing.T) {
 			},
 			wantErr: "interface \"eth99\" not defined in interfaces",
 		},
+		{
+			name: "host interface matched by wildcard",
+			zones: map[string]Zone{
+				"fw":  {Type: ZoneFirewall},
+				"net": {Type: ZoneIP},
+				"lan": {Type: ZoneIP, Parents: []string{"net"}},
+			},
+			interfaces: []Interface{
+				{Zone: "net", Interface: "enp+"},
+			},
+			hosts: []Host{
+				{Zone: "lan", Interface: "enp2s0", Addresses: []string{"192.0.2.0/24"}},
+			},
+		},
 		{
 			name: "zone not defined",
 			zones: map[string]Zone{
@@ -531,6 +545,13 @@ func TestValidateHosts(t *testing.T) {
 			},
 			wantErr: "interface required",
 		},
+		{
+			name:       "invalid exclusion",
+			zones:      map[string]Zone{"fw": {Type: ZoneFirewall}, "net": {Type: ZoneIP}, "loc": {Type: ZoneIP}},
+			interfaces: []Interface{{Zone: "net", Interface: "eth0"}},
+			hosts:      []Host{{Zone: "loc", Interface: "eth0", Addresses: []string{"192.0.2.0/24"}, Exclusions: []string{"192.0.2.0/24!192.0.2.7"}}},
+			wantErr:    "invalid address",
+		},
 	}
 
 	for _, tt := range tests {

internal/config/hosts.go

@@ -1,6 +1,11 @@
 package config
 
-import "fmt"
+import (
+	"fmt"
+	"net/netip"
+	"slices"
+	"strings"
+)
 
 type Host struct {
 	Zone       string      `yaml:"zone"`
@@ -40,7 +45,8 @@ func (c *Config) validateHosts() error {
 
 		ifaceFound := false
 		for _, iface := range c.Interfaces {
-			if iface.Interface == h.Interface || iface.PhysicalName() == h.Interface {
+			prefix, wild := strings.CutSuffix(iface.PhysicalName(), "+")
+			if iface.Interface == h.Interface || iface.PhysicalName() == h.Interface || (wild && strings.HasPrefix(h.Interface, prefix)) {
 				ifaceFound = true
 				break
 			}
@@ -52,6 +58,13 @@ func (c *Config) validateHosts() error {
 		if !h.Dynamic && len(h.Addresses) == 0 {
 			return fmt.Errorf("host[%d]: at least one address required (or set dynamic: true)", i)
 		}
+		for _, a := range slices.Concat(h.Addresses, h.Exclusions) {
+			if _, err := netip.ParsePrefix(a); err != nil {
+				if _, err := netip.ParseAddr(a); err != nil {
+					return fmt.Errorf("host[%d]: invalid address %q", i, a)
+				}
+			}
+		}
 	}
 	return nil
 }

internal/nftables/compiler.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log/slog"
 	"net"
+	"net/netip"
 	"slices"
 	"sort"
 	"strconv"
@@ -66,10 +67,107 @@ func (c *Compiler) Compile() (*FirewallState, error) {
 	}
 	c.compileMSSClamp(state)
 	limitLogs(state, c.cfg.Settings.LogLimit)
+	if err := familyGuards(state, c.cfg.Settings.AddressFamily); err != nil {
+		return nil, err
+	}
 
 	return state, nil
 }
 
+// familyGuards leaves each rule at most one meta nfproto guard, ahead of its first network-header
+// payload as nft emits it; nft list cannot decode repeated or conflicting guards. Rules are built per
+// family, so a conflict is a compiler bug and fails the compile. An ip/ip6 table is its own guard:
+// guards go and other-family rules are dropped.
+func familyGuards(state *FirewallState, family config.AddressFamily) error {
+	table := tableFamily(family)
+	for chain, rules := range state.Rules {
+		var out []ManagedRule
+		for _, r := range rules {
+			fam, ok := guardFamily(r.Exprs)
+			if !ok {
+				return fmt.Errorf("%s %s: conflicting address families", chain, r.Tag)
+			}
+			if table != 0 && fam != 0 && fam != table {
+				continue
+			}
+			r.Exprs = normalizeGuards(r.Exprs, fam, table != 0)
+			out = append(out, r)
+		}
+		state.Rules[chain] = out
+	}
+	return nil
+}
+
+// tableFamily is the NFPROTO an ip/ip6 table is restricted to, 0 for inet.
+func tableFamily(family config.AddressFamily) byte {
+	return map[config.AddressFamily]byte{config.FamilyIP: unix.NFPROTO_IPV4, config.FamilyIP6: unix.NFPROTO_IPV6}[family]
+}
+
+// guardFamily is the family exprs' nfproto guards require (0: none); ok is false when they conflict.
+func guardFamily(exprs []expr.Any) (fam byte, ok bool) {
+	for i := range exprs {
+		if p := nfprotoGuard(exprs, i); p != 0 {
+			if fam != 0 && p != fam {
+				return 0, false
+			}
+			fam = p
+		}
+	}
+	return fam, true
+}
+
+// famsAgree reports whether families (0: any) can all hold for one packet.
+func famsAgree(fams ...byte) bool {
+	var f byte
+	for _, p := range fams {
+		if p != 0 && f != 0 && p != f {
+			return false
+		}
+		if p != 0 {
+			f = p
+		}
+	}
+	return true
+}
+
+func normalizeGuards(in []expr.Any, fam byte, strip bool) []expr.Any {
+	at := -1
+	out := make([]expr.Any, 0, len(in))
+	for i := 0; i < len(in); i++ {
+		if nfprotoGuard(in, i) != 0 {
+			if at < 0 {
+				at = len(out)
+			}
+			i++
+			continue
+		}
+		out = append(out, in[i])
+	}
+	if fam == 0 || strip {
+		return out
+	}
+	if l3 := slices.IndexFunc(out, func(e expr.Any) bool {
+		p, ok := e.(*expr.Payload)
+		return ok && p.Base == expr.PayloadBaseNetworkHeader
+	}); l3 >= 0 && l3 < at {
+		at = l3
+	}
+	return slices.Insert(out, at, matchNFProto(fam)...)
+}
+
+// nfprotoGuard is the family a meta nfproto == match at in[i] guards for, else 0.
+func nfprotoGuard(in []expr.Any, i int) byte {
+	m, ok := in[i].(*expr.Meta)
+	if !ok || m.Key != expr.MetaKeyNFPROTO || i+1 >= len(in) {
+		return 0
+	}
+	c, ok := in[i+1].(*expr.Cmp)
+	if !ok || c.Op != expr.CmpOpEq || c.Register != m.Register || len(c.Data) != 1 {
+		return 0
+	}
+	return c.Data[0]
+}
+
 // limitLogs puts a limit in front of every log expression. A limit stops the
 // whole rule, so like shorewall's separate LOG rule, a log followed by an action
 // splits into a limited log-only rule and the same rule without the log. A
@@ -342,15 +440,15 @@ func (c *Compiler) compileConntrack(state *FirewallState) error {
 func (c *Compiler) compileConntrackPair(state *FirewallState, tag, chain string, ct config.ConntrackRule,
 	srcZone, srcAddr, dstZone, dstAddr string) error {
 	if _, ok := c.cfg.Zones[dstZone]; ok && chain == "raw_prerouting" &&
-		(dstAddr == "" || strings.HasPrefix(dstAddr, "!")) {
+		!narrows(dstAddr) {
 		return fmt.Errorf("conntrack DEST zone %q needs an address in prerouting", dstZone)
 	}
-	srcIfaces, dstIfaces := c.resolveZoneInterfaces(srcZone, srcAddr), []string{""}
-	if chain == "raw_prerouting" && c.resolveZoneInterfaces(dstZone, dstAddr) == nil {
+	srcIfaces, dstIfaces := c.resolveZone(srcZone, srcAddr), []zoneMatch{{}}
+	if chain == "raw_prerouting" && c.resolveZone(dstZone, dstAddr) == nil {
 		return nil
 	}
 	if chain == "raw_output" {
-		srcIfaces, dstIfaces = []string{""}, c.resolveZoneInterfaces(dstZone, dstAddr)
+		srcIfaces, dstIfaces = []zoneMatch{{}}, c.resolveZone(dstZone, dstAddr)
 	}
 	out := chain
 	if ct.Action == config.ConntrackHelper {
@@ -364,6 +462,9 @@ func (c *Compiler) compileConntrackPair(state *FirewallState, tag, chain string,
 			}
 			for _, m := range matches {
 				exprs := m.exprs
+				if _, ok := guardFamily(exprs); !ok {
+					continue
+				}
 				switch ct.Action {
 				case config.ConntrackNoTrack:
 					exprs = append(exprs, &expr.Notrack{})
@@ -407,7 +508,7 @@ func (c *Compiler) compileRules(state *FirewallState) error {
 				return fmt.Errorf("rule[%d]: %w", i, err)
 			}
 			if len(matches)*c.specCount(rule.Source, rule.Dest, rule.OrigDest, fwZone, rule.Action) > 1 {
-				return fmt.Errorf("rule[%d]: ratelimit/connlimit cannot be combined with proto, port, zone or address lists (each expanded rule would get its own limiter)", i)
+				return fmt.Errorf("rule[%d]: ratelimit/connlimit cannot be combined with proto, port, zone or address lists, or with a negated address in an inet table (it expands to one rule per family); each expanded rule would get its own limiter", i)
 			}
 		}
 
@@ -585,19 +686,39 @@ func (c *Compiler) compileDNATAccept(state *FirewallState, tag, srcZone, srcAddr
 	return nil
 }
 
-// specCount is how many zone/address combinations compileOneRule expands src and dst into.
+// specCount is how many rules compileOneRule emits for src and dst once familyGuards has dropped
+// cross-family address combinations and those outside an ip/ip6 table's family.
 func (c *Compiler) specCount(srcSpec, dstSpec, origDest, fwZone string, action config.RuleAction) int {
+	table := tableFamily(c.cfg.Settings.AddressFamily)
+	count := func(addrs ...string) int {
+		n := 0
+		var walk func(i int, fams []byte)
+		walk = func(i int, fams []byte) {
+			if !famsAgree(fams...) {
+				return
+			}
+			if i == len(addrs) {
+				n++
+				return
+			}
+			for _, a := range splitAddrs(addrs[i]) {
+				walk(i+1, append(fams, addrFamily(a)))
+			}
+		}
+		walk(0, []byte{table})
+		return n
+	}
 	n := 0
 	if action == config.RuleDNAT || action == config.RuleRedirect {
 		for _, src := range c.dnatSourceSpecs(srcSpec, fwZone) {
-			n += len(splitAddrs(src.Addr))
+			n += count(src.Addr, origDest)
 		}
-		return n * len(splitAddrs(origDest))
+		return n
 	}
 	for _, p := range c.zonePairs(srcSpec, dstSpec, fwZone) {
-		n += len(splitAddrs(p[0].Addr)) * len(splitAddrs(p[1].Addr))
+		n += count(p[0].Addr, p[1].Addr, origDest)
 	}
-	return n * len(splitAddrs(origDest))
+	return n
 }
 
 // zonePairs is the src/dst zone expansion of a non-DNAT rule, with fw added beside all/any.
@@ -663,19 +784,40 @@ func isZoneExclusion(spec string) bool {
 	return ok && (base == "all" || base == "any")
 }
 
-// splitAddrs yields one alternative per listed address; a negated list stays one AND-ed match.
+// splitAddrs yields one alternative per listed address. A negated list ("everything except") becomes
+// one AND-ed match per family: the family's negations, or the bare family (a /0) when it has none.
 func splitAddrs(addr string) []string {
-	if addr == "" || strings.HasPrefix(addr, "!") {
-		return []string{addr}
+	if addr == "" {
+		return []string{""}
 	}
-	return strings.Split(addr, ",")
+	if !strings.HasPrefix(addr, "!") {
+		return strings.Split(addr, ",")
+	}
+	v4, v6 := splitFamily(strings.Split(addr[1:], ","))
+	out := []string{"0.0.0.0/0", "::/0"}
+	if len(v4) > 0 {
+		out[0] = "!" + strings.Join(v4, ",")
+	}
+	if len(v6) > 0 {
+		out[1] = "!" + strings.Join(v6, ",")
+	}
+	return out
+}
+
+// narrows reports whether a splitAddrs alternative restricts addresses within its family.
+func narrows(addr string) bool {
+	if addr == "" || strings.HasPrefix(addr, "!") {
+		return false
+	}
+	p, err := parsePrefix(addr)
+	return err != nil || p.Bits() > 0
 }
 
 func (c *Compiler) compileZonePair(state *FirewallState, tag, srcZone, srcAddr, dstZone, dstAddr, origDest, proto string,
 	dports, sports config.PortSpec, action config.RuleAction, logLevel string,
 	fwZone string, section config.RuleSection) error {
-	srcIfaces := c.resolveZoneInterfaces(srcZone, srcAddr)
-	dstIfaces := c.resolveZoneInterfaces(dstZone, dstAddr)
+	srcIfaces := c.resolveZone(srcZone, srcAddr)
+	dstIfaces := c.resolveZone(dstZone, dstAddr)
 	chain := c.selectChain(srcZone, dstZone, fwZone)
 	// ponytail: forward daddr is post-DNAT; lift with `ct original daddr` (expr.Ct Direction, google/nftables v0.3.0).
 	if origDest != "" && chain == "forward" {
@@ -689,7 +831,7 @@ func (c *Compiler) compileZonePair(state *FirewallState, tag, srcZone, srcAddr,
 				return err
 			}
 			if origDest != "" {
-				od, err := matchOrigDest(origDest)
+				od, err := matchDestCIDR(origDest)
 				if err != nil {
 					return fmt.Errorf("origdest: %w", err)
 				}
@@ -700,6 +842,9 @@ func (c *Compiler) compileZonePair(state *FirewallState, tag, srcZone, srcAddr,
 
 			for _, m := range matches {
 				exprs := m.exprs
+				if _, ok := guardFamily(exprs); !ok {
+					continue
+				}
 
 				if section != "" && section != config.SectionAll {
 					exprs = append(exprs, matchSection(section)...)
@@ -744,12 +889,12 @@ func (c *Compiler) compileDNATRule(state *FirewallState, tag, srcZone, srcAddr,
 		dnatPort = uint16(p)
 	}
 
-	srcIfaces := c.resolveZoneInterfaces(srcZone, srcAddr)
+	srcIfaces := c.resolveZone(srcZone, srcAddr)
 
 	var odExprs []expr.Any
 	if origDest != "" {
 		var err error
-		if odExprs, err = matchOrigDest(origDest); err != nil {
+		if odExprs, err = matchDestCIDR(origDest); err != nil {
 			return fmt.Errorf("origdest: %w", err)
 		}
 	}
@@ -763,14 +908,18 @@ func (c *Compiler) compileDNATRule(state *FirewallState, tag, srcZone, srcAddr,
 	if ip == nil {
 		return fmt.Errorf("invalid DNAT address %q", dnatAddr)
 	}
+	natFam := byte(0)
+	if action != config.RuleRedirect {
+		natFam = addrFamily(dnatAddr)
+	}
 
 	for _, srcIface := range srcIfaces {
+		zm, err := zoneMatchExprs(srcIface, true)
+		if err != nil {
+			return err
+		}
 		for _, m := range matches {
-			var exprs []expr.Any
-
-			if srcIface != "" {
-				exprs = append(exprs, matchIfaceName(true, srcIface)...)
-			}
+			exprs := slices.Clone(zm)
 
 			if srcAddr != "" {
 				src, err := matchSourceCIDR(srcAddr)
@@ -780,6 +929,9 @@ func (c *Compiler) compileDNATRule(state *FirewallState, tag, srcZone, srcAddr,
 				exprs = append(exprs, src...)
 			}
 			exprs = append(exprs, odExprs...)
+			if f, ok := guardFamily(exprs); !ok || !famsAgree(f, natFam) {
+				continue
+			}
 
 			exprs = append(exprs, m.exprs...)
 
@@ -857,31 +1009,35 @@ func (c *Compiler) compileDNATRule(state *FirewallState, tag, srcZone, srcAddr,
 func (c *Compiler) compilePolicies(state *FirewallState) error {
 	fwZone := c.cfg.FirewallZone()
 
+	overridden := map[string]bool{}
 	for i, pol := range c.cfg.Policy {
 		tag := fmt.Sprintf("policy:%d", i)
+		explicitIntra := pol.Source == pol.Dest && !isGlobalZone(pol.Source)
 
 		srcZones := c.expandZoneRef(pol.Source)
 		dstZones := c.expandZoneRef(pol.Dest)
 
 		for _, sz := range srcZones {
 			for _, dz := range dstZones {
-				if sz == dz && !strings.HasSuffix(pol.Source, "+") {
-					continue
+				if sz == dz {
+					if sz == fwZone || (!explicitIntra && !strings.HasSuffix(pol.Source, "+") && !strings.HasSuffix(pol.Dest, "+")) {
+						continue
+					}
+					overridden[sz] = true
 				}
 
 				chain := c.selectChain(sz, dz, fwZone)
-				srcIfaces := c.resolveZoneInterfaces(sz, "")
-				dstIfaces := c.resolveZoneInterfaces(dz, "")
+				srcIfaces := c.resolveZone(sz, "")
+				dstIfaces := c.resolveZone(dz, "")
 
 				for _, si := range srcIfaces {
 					for _, di := range dstIfaces {
-						var exprs []expr.Any
-
-						if si != "" {
-							exprs = append(exprs, matchIfaceName(true, si)...)
+						if sz == dz && intraZoneSkip(si, di) || chain != "input" && !famsAgree(matchFamily(si), matchFamily(di)) {
+							continue
 						}
-						if di != "" && chain != "input" {
-							exprs = append(exprs, matchIfaceName(false, di)...)
+						exprs, err := zonePairExprs(si, di, chain)
+						if err != nil {
+							return fmt.Errorf("policy[%d]: %w", i, err)
 						}
 
 						if pol.RateLimit != "" {
@@ -909,32 +1065,91 @@ func (c *Compiler) compilePolicies(state *FirewallState) error {
 		}
 	}
 
+	return c.compileImplicitIntraZone(state, overridden)
+}
+
+// compileImplicitIntraZone accepts traffic between different interfaces of one zone, shorewall's implicit intra-zone ACCEPT policy.
+func (c *Compiler) compileImplicitIntraZone(state *FirewallState, overridden map[string]bool) error {
+	fwZone := c.cfg.FirewallZone()
+	zones := make([]string, 0, len(c.cfg.Zones))
+	for z := range c.cfg.Zones {
+		zones = append(zones, z)
+	}
+	sort.Strings(zones)
+	for _, z := range zones {
+		if z == fwZone || overridden[z] {
+			continue
+		}
+		if len(c.cfg.ZoneInterfaces(z)) == 0 && !slices.ContainsFunc(c.cfg.Hosts, func(h config.Host) bool { return h.Zone == z }) {
+			continue
+		}
+		matches := c.resolveZone(z, "")
+		for _, si := range matches {
+			for _, di := range matches {
+				if intraZoneSkip(si, di) {
+					continue
+				}
+				exprs, err := zonePairExprs(si, di, "forward")
+				if err != nil {
+					return fmt.Errorf("zone %s: %w", z, err)
+				}
+				state.Rules["forward"] = append(state.Rules["forward"], ManagedRule{
+					Chain: "forward",
+					Exprs: append(exprs, &expr.Verdict{Kind: expr.VerdictAccept}),
+					Tag:   "intra:" + z,
+				})
+			}
+		}
+	}
 	return nil
 }
 
+// intraZoneSkip drops intra-zone pairs on one interface unless both are routeback hosts entries
+// (interface routeback is compileIntraZone's job), and pairs whose address families can never both match.
+func intraZoneSkip(si, di zoneMatch) bool {
+	if si.iface != "" && si.iface == di.iface && !(si.routeback && di.routeback) {
+		return true
+	}
+	a, b := matchFamily(si), matchFamily(di)
+	return a != 0 && b != 0 && a != b
+}
+
+// matchFamily is the NFPROTO a zoneMatch is guarded by: its host address's family, else fam.
+func matchFamily(m zoneMatch) byte {
+	if p, err := parsePrefix(m.addr); err == nil {
+		if p.Addr().Is4() {
+			return unix.NFPROTO_IPV4
+		}
+		return unix.NFPROTO_IPV6
+	}
+	return m.fam
+}
+
 func (c *Compiler) compileSNAT(state *FirewallState) error {
 	for i, snat := range c.cfg.SNAT {
 		tag := fmt.Sprintf("snat:%d", i)
 
-		var exprs []expr.Any
-
 		destIface, _ := splitZoneSpec(snat.Dest)
-		exprs = append(exprs, matchIfaceName(false, destIface)...)
-
-		if snat.Source != "" {
-			srcExprs, err := matchSourceCIDR(snat.Source)
-			if err != nil {
-				return fmt.Errorf("snat[%d]: %w", i, err)
+		var heads [][]expr.Any
+		for _, src := range splitAddrs(snat.Source) {
+			head := matchIfaceName(false, destIface)
+			if src != "" {
+				srcExprs, err := matchSourceCIDR(src)
+				if err != nil {
+					return fmt.Errorf("snat[%d]: %w", i, err)
+				}
+				head = append(head, srcExprs...)
+			}
+			if snat.Action != config.SNATAddress || famsAgree(addrFamily(src), addrFamily(snat.Address)) {
+				heads = append(heads, head)
 			}
-			exprs = append(exprs, srcExprs...)
 		}
 
 		matches, err := l4Matches(snat.Proto, snat.DPort, snat.SPort)
 		if err != nil {
 			return fmt.Errorf("snat[%d]: %w", i, err)
 		}
-		head := exprs
-		exprs = nil
+		var exprs []expr.Any
 
 		if snat.Mark != "" {
 			exprs = append(exprs, matchMark(snat.Mark)...)
@@ -980,12 +1195,14 @@ func (c *Compiler) compileSNAT(state *FirewallState) error {
 			}
 		}
 
-		for _, m := range matches {
-			state.Rules["postrouting"] = append(state.Rules["postrouting"], ManagedRule{
-				Chain: "postrouting",
-				Exprs: append(append(append([]expr.Any{}, head...), m.exprs...), exprs...),
-				Tag:   tag,
-			})
+		for _, head := range heads {
+			for _, m := range matches {
+				state.Rules["postrouting"] = append(state.Rules["postrouting"], ManagedRule{
+					Chain: "postrouting",
+					Exprs: slices.Concat(head, m.exprs, exprs),
+					Tag:   tag,
+				})
+			}
 		}
 	}
 
@@ -1213,11 +1430,25 @@ func (c *Compiler) selectChain(srcZone, dstZone, fwZone string) string {
 	return "forward"
 }
 
-// resolveZoneInterfaces returns nil (fail closed) for an unknown zone, or one with no interfaces unless a non-negated address match narrows the rule.
-func (c *Compiler) resolveZoneInterfaces(zone, addr string) []string {
+// zoneMatch classifies a packet into a zone: an interface (empty: any) and, for a hosts entry, one host
+// address; excl carves out hosts exclusions and the hosts of sub-zones, which shorewall matches first.
+// fam (an NFPROTO; addr's family when set, else 0: any) guards addr and excl so IPv4 offsets are
+// never compared against IPv6 bytes. routeback marks a hosts entry with the routeback option. notIface
+// carves narrower sub-zone host interfaces out of a wildcard iface; they get entries of their own.
+type zoneMatch struct {
+	iface, addr string
+	notIface    []string
+	excl        []string
+	fam         byte
+	routeback   bool
+}
+
+// resolveZone returns nil (fail closed) for an unknown zone, or one with neither interfaces nor hosts
+// unless a non-negated address match narrows the rule.
+func (c *Compiler) resolveZone(zone, addr string) []zoneMatch {
 	switch zone {
 	case "", "all", "all+", "any", "any+":
-		return []string{""}
+		return []zoneMatch{{}}
 	}
 	z, ok := c.cfg.Zones[zone]
 	if !ok {
@@ -1225,24 +1456,188 @@ func (c *Compiler) resolveZoneInterfaces(zone, addr string) []string {
 		return nil
 	}
 	if z.Type == config.ZoneFirewall {
-		return []string{""}
+		return []zoneMatch{{}}
 	}
-	if ifaces := c.cfg.ZoneInterfaces(zone); len(ifaces) > 0 {
-		return ifaces
+	var out []zoneMatch
+	hasHosts := false
+	for _, iface := range c.cfg.ZoneInterfaces(zone) {
+		for _, sp := range c.subZoneSplit(zone, iface) {
+			if len(sp.sub) == 0 {
+				out = append(out, zoneMatch{iface: sp.iface, notIface: sp.not})
+			} else {
+				v4, v6 := splitFamily(sp.sub)
+				out = append(out, zoneMatch{iface: sp.iface, notIface: sp.not, excl: v4, fam: unix.NFPROTO_IPV4},
+					zoneMatch{iface: sp.iface, notIface: sp.not, excl: v6, fam: unix.NFPROTO_IPV6})
+			}
+			for _, b := range sp.back {
+				if addrsOverlap(b, addr) {
+					out = append(out, zoneMatch{iface: sp.iface, notIface: sp.not, addr: b})
+				}
+			}
+		}
 	}
-	if addr != "" && !strings.HasPrefix(addr, "!") {
-		return []string{""}
+	for _, h := range c.cfg.Hosts {
+		if h.Zone != zone {
+			continue
+		}
+		hasHosts = true
+		for _, sp := range c.subZoneSplit(zone, h.Interface) {
+			v4, v6 := splitFamily(slices.Concat(h.Exclusions, sp.sub))
+			for _, a := range h.Addresses {
+				if addrsOverlap(a, addr) {
+					m := zoneMatch{iface: sp.iface, notIface: sp.not, addr: a, excl: v6, routeback: h.Options.RouteBack}
+					if p, err := parsePrefix(a); err == nil && p.Addr().Is4() {
+						m.excl = v4
+					}
+					out = append(out, m)
+				}
+			}
+		}
+	}
+	if len(out) > 0 || hasHosts {
+		return out
+	}
+	if narrows(addr) {
+		return []zoneMatch{{}}
 	}
 	if !c.warned[zone] {
 		if c.warned == nil {
 			c.warned = map[string]bool{}
 		}
 		c.warned[zone] = true
-		slog.Warn("compiler: zone has no interfaces, skipping its rules", "zone", zone)
+		slog.Warn("compiler: zone has no interfaces or hosts, skipping its rules", "zone", zone)
 	}
 	return nil
 }
 
+// subZoneSplit partitions iface for zone's sub-zone hosts, as shorewall matches them: the hosts on an
+// interface covering iface exclude their addresses (sub) on all of it, while a host interface strictly
+// inside a wildcard iface is carved out (not) into its own entry, so its addresses stay in zone on every
+// other interface the wildcard matches. back lists the sub-zone hosts' exclusions, which fall back to zone.
+type subZoneSplit struct {
+	iface     string
+	not       []string
+	sub, back []string
+}
+
+func (c *Compiler) subZoneSplit(zone, iface string) []subZoneSplit {
+	top := subZoneSplit{iface: iface}
+	var inner []string
+	for _, h := range c.cfg.Hosts {
+		switch {
+		case !c.cfg.IsSubZone(h.Zone, zone):
+		case ifaceCovers(h.Interface, iface):
+			top.sub = append(top.sub, h.Addresses...)
+			top.back = append(top.back, h.Exclusions...)
+		case ifaceCovers(iface, h.Interface) && !slices.Contains(inner, h.Interface):
+			inner = append(inner, h.Interface)
+		}
+	}
+	var rest []subZoneSplit
+	for _, h := range inner {
+		if slices.ContainsFunc(inner, func(o string) bool { return o != h && ifaceCovers(o, h) }) {
+			continue
+		}
+		top.not = append(top.not, h)
+		rest = append(rest, c.subZoneSplit(zone, h)...)
+	}
+	return append([]subZoneSplit{top}, rest...)
+}
+
+// ifaceCovers reports whether every interface name b matches is also matched by a ("+" suffix: prefix wildcard).
+func ifaceCovers(a, b string) bool {
+	if pa, ok := strings.CutSuffix(a, "+"); ok {
+		return strings.HasPrefix(strings.TrimSuffix(b, "+"), pa)
+	}
+	return a == b
+}
+
+// addrsOverlap reports whether a host address can match a rule address; unparsable or negated rule addresses keep the host.
+func addrsOverlap(host, rule string) bool {
+	if rule == "" || strings.HasPrefix(rule, "!") {
+		return true
+	}
+	h, err := parsePrefix(host)
+	if err != nil {
+		return true
+	}
+	for _, r := range strings.Split(rule, ",") {
+		if p, err := parsePrefix(r); err != nil || p.Overlaps(h) {
+			return true
+		}
+	}
+	return false
+}
+
+// splitFamily partitions addresses by family; unparsable ones go to v6 so zoneMatchExprs still rejects them.
+func splitFamily(addrs []string) (v4, v6 []string) {
+	for _, a := range addrs {
+		if p, err := parsePrefix(a); err == nil && p.Addr().Is4() {
+			v4 = append(v4, a)
+		} else {
+			v6 = append(v6, a)
+		}
+	}
+	return v4, v6
+}
+
+func parsePrefix(s string) (netip.Prefix, error) {
+	if a, err := netip.ParseAddr(s); err == nil {
+		return netip.PrefixFrom(a, a.BitLen()), nil
+	}
+	return netip.ParsePrefix(s)
+}
+
+// zoneMatchExprs matches a zone on the in (src) or out interface plus its host address and exclusions,
+// all guarded by m.fam so an IPv4 address never matches IPv6 bytes in an inet table.
+func zoneMatchExprs(m zoneMatch, src bool) ([]expr.Any, error) {
+	var out []expr.Any
+	if m.iface != "" {
+		out = matchIfaceName(src, m.iface)
+	}
+	for _, n := range m.notIface {
+		e := matchIfaceName(src, n)
+		e[1].(*expr.Cmp).Op = expr.CmpOpNeq
+		out = append(out, e...)
+	}
+	var addr []expr.Any
+	if m.addr != "" {
+		p, err := parsePrefix(m.addr)
+		if err != nil {
+			return nil, fmt.Errorf("invalid host address %q", m.addr)
+		}
+		if addr, err = matchAddrCIDR(m.addr, src); err != nil {
+			return nil, err
+		}
+		m.fam = unix.NFPROTO_IPV6
+		if p.Addr().Is4() {
+			m.fam = unix.NFPROTO_IPV4
+		}
+	}
+	if m.fam != 0 {
+		out = append(out, matchNFProto(m.fam)...)
+	}
+	out = append(out, addr...)
+	if len(m.excl) > 0 {
+		e, err := matchAddrCIDR("!"+strings.Join(m.excl, ","), src)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, e...)
+	}
+	return out, nil
+}
+
+// zonePairExprs matches the source zone inbound and, outside input, the dest zone outbound.
+func zonePairExprs(src, dst zoneMatch, chain string) ([]expr.Any, error) {
+	out, err := zoneMatchExprs(src, true)
+	if err != nil || chain == "input" {
+		return out, err
+	}
+	d, err := zoneMatchExprs(dst, false)
+	return append(out, d...), err
+}
+
 func (c *Compiler) expandZoneRef(ref string) []string {
 	base := ref
 	var excluded map[string]bool
@@ -1272,14 +1667,10 @@ func (c *Compiler) expandZoneRef(ref string) []string {
 	return []string{base}
 }
 
-func (c *Compiler) buildMatchExprs(srcIface, dstIface, chain, proto string, dports, sports config.PortSpec, srcAddr, dstAddr string) ([]l4Match, error) {
-	var exprs []expr.Any
-
-	if srcIface != "" {
-		exprs = append(exprs, matchIfaceName(true, srcIface)...)
-	}
-	if dstIface != "" && chain != "input" {
-		exprs = append(exprs, matchIfaceName(false, dstIface)...)
+func (c *Compiler) buildMatchExprs(srcIface, dstIface zoneMatch, chain, proto string, dports, sports config.PortSpec, srcAddr, dstAddr string) ([]l4Match, error) {
+	exprs, err := zonePairExprs(srcIface, dstIface, chain)
+	if err != nil {
+		return nil, err
 	}
 
 	if srcAddr != "" {
@@ -1500,6 +1891,7 @@ func matchTCPFlags(flags, mask byte) []expr.Any {
 func matchSmurfDrop(iface string) []expr.Any {
 	var exprs []expr.Any
 	exprs = append(exprs, matchIfaceName(true, iface)...)
+	exprs = append(exprs, matchNFProto(unix.NFPROTO_IPV4)...)
 	exprs = append(exprs,
 		&expr.Payload{DestRegister: 1, Base: expr.PayloadBaseNetworkHeader, Offset: 12, Len: 4},
 		&expr.Bitwise{
@@ -1660,32 +2052,35 @@ func parseSPortOrRange(s string) ([]expr.Any, error) {
 }
 
 func matchSourceCIDR(cidr string) ([]expr.Any, error) {
-	return matchAddrCIDR(cidr, true)
+	return matchGuardedCIDR(cidr, true)
 }
 
 func matchDestCIDR(cidr string) ([]expr.Any, error) {
-	return matchAddrCIDR(cidr, false)
+	return matchGuardedCIDR(cidr, false)
 }
 
-// matchOrigDest guards the daddr match with the address's nfproto so it is family-correct in the inet table.
-func matchOrigDest(addr string) ([]expr.Any, error) {
-	var proto byte
-	for i, a := range strings.Split(strings.TrimPrefix(addr, "!"), ",") {
-		a, _, _ = strings.Cut(a, "/")
-		p := byte(unix.NFPROTO_IPV6)
-		if ip := net.ParseIP(a); ip != nil && ip.To4() != nil {
-			p = unix.NFPROTO_IPV4
-		}
-		if i > 0 && p != proto {
-			return nil, fmt.Errorf("%q mixes IPv4 and IPv6 addresses", addr)
-		}
-		proto = p
+// matchGuardedCIDR guards a single-family splitAddrs alternative with its nfproto; a /0 is the guard alone.
+func matchGuardedCIDR(cidr string, isSrc bool) ([]expr.Any, error) {
+	if !narrows(cidr) && !strings.HasPrefix(cidr, "!") {
+		return matchNFProto(addrFamily(cidr)), nil
 	}
-	dst, err := matchDestCIDR(addr)
+	e, err := matchAddrCIDR(cidr, isSrc)
 	if err != nil {
 		return nil, err
 	}
-	return append(matchNFProto(proto), dst...), nil
+	return append(matchNFProto(addrFamily(cidr)), e...), nil
+}
+
+// addrFamily is the NFPROTO of a single-family splitAddrs alternative, 0 for none; unparsable is IPv6.
+func addrFamily(list string) byte {
+	if list == "" {
+		return 0
+	}
+	a, _, _ := strings.Cut(strings.TrimPrefix(list, "!"), ",")
+	if p, err := parsePrefix(a); err == nil && p.Addr().Is4() {
+		return unix.NFPROTO_IPV4
+	}
+	return unix.NFPROTO_IPV6
 }
 
 func matchNFProto(proto byte) []expr.Any {

internal/nftables/compiler_test.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"net"
 	"reflect"
+	"slices"
 	"strings"
 	"testing"
 
@@ -144,19 +145,17 @@ func TestCompiler_ResolveZoneInterfaces(t *testing.T) {
 	}
 	c := NewCompiler(cfg)
 
-	ifaces := c.resolveZoneInterfaces("net", "")
-	if len(ifaces) != 1 || ifaces[0] != "eth0" {
-		t.Errorf("resolveZoneInterfaces(net) = %v, want [eth0]", ifaces)
-	}
-
-	ifaces = c.resolveZoneInterfaces("all", "")
-	if len(ifaces) != 1 || ifaces[0] != "" {
-		t.Errorf("resolveZoneInterfaces(all) = %v, want [\"\"]", ifaces)
-	}
-
-	ifaces = c.resolveZoneInterfaces("fw", "")
-	if len(ifaces) != 1 || ifaces[0] != "" {
-		t.Errorf("resolveZoneInterfaces(fw) = %v, want [\"\"]", ifaces)
+	for _, tt := range []struct {
+		zone string
+		want []zoneMatch
+	}{
+		{"net", []zoneMatch{{iface: "eth0"}}},
+		{"all", []zoneMatch{{}}},
+		{"fw", []zoneMatch{{}}},
+	} {
+		if got := c.resolveZone(tt.zone, ""); !reflect.DeepEqual(got, tt.want) {
+			t.Errorf("resolveZone(%s) = %v, want %v", tt.zone, got, tt.want)
+		}
 	}
 }
 
@@ -211,7 +210,7 @@ func TestMatchSourceCIDR_IPv6(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		exprs, err := matchSourceCIDR(tt.input)
+		exprs, err := matchAddrCIDR(tt.input, true)
 		if tt.wantErr {
 			if err == nil {
 				t.Errorf("matchSourceCIDR(%q) should fail", tt.input)
@@ -242,7 +241,7 @@ func TestMatchDestCIDR_IPv6(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		exprs, err := matchDestCIDR(tt.input)
+		exprs, err := matchAddrCIDR(tt.input, false)
 		if tt.wantErr {
 			if err == nil {
 				t.Errorf("matchDestCIDR(%q) should fail", tt.input)
@@ -962,7 +961,7 @@ func TestCompile_RateLimit(t *testing.T) {
 }
 
 func TestNegatedAddress(t *testing.T) {
-	exprs, err := matchSourceCIDR("!192.168.1.0/24")
+	exprs, err := matchAddrCIDR("!192.168.1.0/24", true)
 	if err != nil {
 		t.Fatalf("matchSourceCIDR(!192.168.1.0/24) error: %v", err)
 	}
@@ -974,7 +973,7 @@ func TestNegatedAddress(t *testing.T) {
 		t.Errorf("negated address should use CmpOpNeq, got %v", cmp.Op)
 	}
 
-	exprs, err = matchDestCIDR("!10.0.0.1")
+	exprs, err = matchAddrCIDR("!10.0.0.1", false)
 	if err != nil {
 		t.Fatalf("matchDestCIDR(!10.0.0.1) error: %v", err)
 	}
@@ -1849,13 +1848,13 @@ func TestCompile_InterfacelessZonesFailClosed(t *testing.T) {
 			c.Zones["hst"] = config.Zone{Type: config.ZoneIP}
 			c.Hosts = []config.Host{{Zone: "hst", Interface: "eth0", Addresses: []string{"192.0.2.0/24"}}}
 			c.Policy = []config.Policy{{Source: "fw", Dest: "hst", Action: config.PolicyAccept}}
-		}, "policy:0", 0, []string{"hst"}},
+		}, "policy:0", 1, nil},
 		{"fw all expansion keeps zones with interfaces", func(c *config.Config) {
 			ipsec(c)
 			c.Zones["hst"] = config.Zone{Type: config.ZoneIP}
 			c.Hosts = []config.Host{{Zone: "hst", Interface: "eth0", Addresses: []string{"192.0.2.0/24"}}}
 			c.Policy = []config.Policy{{Source: "fw", Dest: "all", Action: config.PolicyDrop}}
-		}, "policy:0", 1, []string{"hst", "ips"}},
+		}, "policy:0", 2, []string{"ips"}},
 		{"negated address does not scope", rule("ips:!192.0.2.1"), "rule:0", 0, []string{"ips"}},
 		{"address scopes", rule("ips:192.0.2.1"), "rule:0", 1, []string{"ips"}},
 	}
@@ -1895,6 +1894,19 @@ func TestCompile_InterfacelessZonesFailClosed(t *testing.T) {
 func describeRule(r ManagedRule) string {
 	var parts []string
 	for i, e := range r.Exprs {
+		if p, ok := e.(*expr.Payload); ok && p.Base == expr.PayloadBaseNetworkHeader && i+2 < len(r.Exprs) {
+			bw, okb := r.Exprs[i+1].(*expr.Bitwise)
+			cmp, okc := r.Exprs[i+2].(*expr.Cmp)
+			if okb && okc {
+				name := map[uint32]string{12: "saddr", 16: "daddr", 8: "saddr", 24: "daddr"}[p.Offset]
+				if cmp.Op == expr.CmpOpNeq {
+					name = "!" + name
+				}
+				ones, _ := net.IPMask(bw.Mask).Size()
+				parts = append(parts, fmt.Sprintf("%s=%s/%d", name, net.IP(cmp.Data), ones))
+				continue
+			}
+		}
 		cmp, ok := func() (*expr.Cmp, bool) {
 			if i+1 >= len(r.Exprs) {
 				return nil, false
@@ -1909,9 +1921,19 @@ func describeRule(r ManagedRule) string {
 		case *expr.Meta:
 			switch m.Key {
 			case expr.MetaKeyIIFNAME:
-				parts = append(parts, "iif="+strings.TrimRight(string(cmp.Data), "\x00"))
+				op := "="
+				if cmp.Op == expr.CmpOpNeq {
+					op = "!="
+				}
+				parts = append(parts, "iif"+op+strings.TrimRight(string(cmp.Data), "\x00"))
 			case expr.MetaKeyOIFNAME:
-				parts = append(parts, "oif="+strings.TrimRight(string(cmp.Data), "\x00"))
+				op := "="
+				if cmp.Op == expr.CmpOpNeq {
+					op = "!="
+				}
+				parts = append(parts, "oif"+op+strings.TrimRight(string(cmp.Data), "\x00"))
+			case expr.MetaKeyNFPROTO:
+				parts = append(parts, map[byte]string{unix.NFPROTO_IPV4: "ip4", unix.NFPROTO_IPV6: "ip6"}[cmp.Data[0]])
 			}
 		case *expr.Payload:
 			if m.Base == expr.PayloadBaseNetworkHeader && (m.Len == 4 || m.Len == 16) {
@@ -1954,57 +1976,57 @@ func TestCompile_CommaZoneLists(t *testing.T) {
 		{
 			name: "address list after colon belongs to one zone",
 			rule: config.Rule{Action: config.RuleAccept, Source: "lan", Dest: "net:192.0.2.1,198.51.100.1"},
-			want: map[string][]string{"forward": {"iif=eth1 oif=eth0 daddr=192.0.2.1", "iif=eth1 oif=eth0 daddr=198.51.100.1"}},
+			want: map[string][]string{"forward": {"iif=eth1 oif=eth0 ip4 daddr=192.0.2.1", "iif=eth1 oif=eth0 ip4 daddr=198.51.100.1"}},
 		},
 		{
 			name: "zone:address inside a list",
 			rule: config.Rule{Action: config.RuleAccept, Source: "lan,svr:203.0.113.7", Dest: "fw"},
-			want: map[string][]string{"input": {"iif=eth1", "iif=eth2 saddr=203.0.113.7"}},
+			want: map[string][]string{"input": {"iif=eth1", "iif=eth2 ip4 saddr=203.0.113.7"}},
 		},
 		{
 			name: "dnat source list",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "net,lan", Dest: "svr:192.0.2.10", Proto: "tcp", DPort: config.PortSpec{"80"}},
 			want: map[string][]string{"prerouting": {"iif=eth0", "iif=eth1"},
-				"forward": {"iif=eth0 oif=eth2 daddr=192.0.2.10", "iif=eth1 oif=eth2 daddr=192.0.2.10"}},
+				"forward": {"iif=eth0 oif=eth2 ip4 daddr=192.0.2.10", "iif=eth1 oif=eth2 ip4 daddr=192.0.2.10"}},
 		},
 		{
 			name: "dnat source list skips the target zone",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "net,svr", Dest: "svr:192.0.2.10", Proto: "tcp", DPort: config.PortSpec{"80"}},
-			want: map[string][]string{"prerouting": {"iif=eth0"}, "forward": {"iif=eth0 oif=eth2 daddr=192.0.2.10"}},
+			want: map[string][]string{"prerouting": {"iif=eth0"}, "forward": {"iif=eth0 oif=eth2 ip4 daddr=192.0.2.10"}},
 		},
 		{
 			name: "dnat lone source zone may equal the target zone",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "svr", Dest: "svr:192.0.2.10", Proto: "tcp", DPort: config.PortSpec{"80"}},
-			want: map[string][]string{"prerouting": {"iif=eth2"}, "forward": {"iif=eth2 oif=eth2 daddr=192.0.2.10"}},
+			want: map[string][]string{"prerouting": {"iif=eth2"}, "forward": {"iif=eth2 oif=eth2 ip4 daddr=192.0.2.10"}},
 		},
 		{
 			name: "dnat exclusion source skips the target zone",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "all!fw,anycast", Dest: "svr:192.0.2.10", Proto: "tcp", DPort: config.PortSpec{"80"}},
 			want: map[string][]string{"prerouting": {"iif=eth1", "iif=eth0"},
-				"forward": {"iif=eth1 oif=eth2 daddr=192.0.2.10", "iif=eth0 oif=eth2 daddr=192.0.2.10"}},
+				"forward": {"iif=eth1 oif=eth2 ip4 daddr=192.0.2.10", "iif=eth0 oif=eth2 ip4 daddr=192.0.2.10"}},
 		},
 		{
 			name: "dnat intrazone exclusion source keeps the target zone",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "all+!fw,anycast,lan", Dest: "svr:192.0.2.10", Proto: "tcp", DPort: config.PortSpec{"80"}},
 			want: map[string][]string{"prerouting": {"iif=eth0", "iif=eth2"},
-				"forward": {"iif=eth0 oif=eth2 daddr=192.0.2.10", "iif=eth2 oif=eth2 daddr=192.0.2.10"}},
+				"forward": {"iif=eth0 oif=eth2 ip4 daddr=192.0.2.10", "iif=eth2 oif=eth2 ip4 daddr=192.0.2.10"}},
 		},
 		{
 			name: "dnat all source expands per zone and skips fw and the target zone",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "all", Dest: "svr:192.0.2.10", Proto: "tcp", DPort: config.PortSpec{"80"}},
 			want: map[string][]string{"prerouting": {"iif=eth3", "iif=eth1", "iif=eth0"},
-				"forward": {"iif=eth3 oif=eth2 daddr=192.0.2.10", "iif=eth1 oif=eth2 daddr=192.0.2.10", "iif=eth0 oif=eth2 daddr=192.0.2.10"}},
+				"forward": {"iif=eth3 oif=eth2 ip4 daddr=192.0.2.10", "iif=eth1 oif=eth2 ip4 daddr=192.0.2.10", "iif=eth0 oif=eth2 ip4 daddr=192.0.2.10"}},
 		},
 		{
 			name: "dnat any+ source keeps the target zone",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "any+", Dest: "svr:192.0.2.10", Proto: "tcp", DPort: config.PortSpec{"80"}},
 			want: map[string][]string{"prerouting": {"iif=eth3", "iif=eth1", "iif=eth0", "iif=eth2"},
-				"forward": {"iif=eth3 oif=eth2 daddr=192.0.2.10", "iif=eth1 oif=eth2 daddr=192.0.2.10", "iif=eth0 oif=eth2 daddr=192.0.2.10", "iif=eth2 oif=eth2 daddr=192.0.2.10"}},
+				"forward": {"iif=eth3 oif=eth2 ip4 daddr=192.0.2.10", "iif=eth1 oif=eth2 ip4 daddr=192.0.2.10", "iif=eth0 oif=eth2 ip4 daddr=192.0.2.10", "iif=eth2 oif=eth2 ip4 daddr=192.0.2.10"}},
 		},
 		{
 			name: "dnat to fw accepts in input",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "net", Dest: "fw:192.0.2.1", Proto: "tcp", DPort: config.PortSpec{"80"}},
-			want: map[string][]string{"prerouting": {"iif=eth0"}, "input": {"iif=eth0 daddr=192.0.2.1"}},
+			want: map[string][]string{"prerouting": {"iif=eth0"}, "input": {"iif=eth0 ip4 daddr=192.0.2.1"}},
 		},
 		{
 			name: "redirect accepts in input without daddr",
@@ -2014,13 +2036,13 @@ func TestCompile_CommaZoneLists(t *testing.T) {
 		{
 			name: "dnat source address list",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "net:192.0.2.5,198.51.100.5", Dest: "svr:192.0.2.10", Proto: "tcp", DPort: config.PortSpec{"80"}},
-			want: map[string][]string{"prerouting": {"iif=eth0 saddr=192.0.2.5", "iif=eth0 saddr=198.51.100.5"},
-				"forward": {"iif=eth0 oif=eth2 saddr=192.0.2.5 daddr=192.0.2.10", "iif=eth0 oif=eth2 saddr=198.51.100.5 daddr=192.0.2.10"}},
+			want: map[string][]string{"prerouting": {"iif=eth0 ip4 saddr=192.0.2.5", "iif=eth0 ip4 saddr=198.51.100.5"},
+				"forward": {"iif=eth0 oif=eth2 ip4 saddr=192.0.2.5 daddr=192.0.2.10", "iif=eth0 oif=eth2 ip4 saddr=198.51.100.5 daddr=192.0.2.10"}},
 		},
 		{
-			name: "negated address list stays one AND-ed rule",
+			name: "negated address list is one AND-ed rule per family",
 			rule: config.Rule{Action: config.RuleAccept, Source: "net:!192.0.2.5,198.51.100.5", Dest: "fw"},
-			want: map[string][]string{"input": {"iif=eth0 !saddr=192.0.2.5 !saddr=198.51.100.5"}},
+			want: map[string][]string{"input": {"iif=eth0 ip4 !saddr=192.0.2.5 !saddr=198.51.100.5", "iif=eth0 ip6"}},
 		},
 		{
 			name: "zone named like all/any keyword is a plain zone",
@@ -2035,7 +2057,7 @@ func TestCompile_CommaZoneLists(t *testing.T) {
 		{
 			name: "interface-less zone kept when address narrows it",
 			rule: config.Rule{Action: config.RuleAccept, Source: "lan", Dest: "vpn:192.0.2.1"},
-			want: map[string][]string{"forward": {"iif=eth1 daddr=192.0.2.1"}},
+			want: map[string][]string{"forward": {"iif=eth1 ip4 daddr=192.0.2.1"}},
 		},
 		{
 			name: "fw source matches dest zone oif",
@@ -2045,30 +2067,30 @@ func TestCompile_CommaZoneLists(t *testing.T) {
 		{
 			name: "fw to all has no oif",
 			rule: config.Rule{Action: config.RuleAccept, Source: "fw", Dest: "all:192.0.2.1"},
-			want: map[string][]string{"output": {"daddr=192.0.2.1"}},
+			want: map[string][]string{"output": {"ip4 daddr=192.0.2.1"}},
 		},
 		{
 			name: "dnat origdest",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "net", Dest: "svr:192.0.2.17", Proto: "tcp", DPort: config.PortSpec{"80"}, OrigDest: "203.0.113.5"},
-			want: map[string][]string{"prerouting": {"iif=eth0 daddr=203.0.113.5"},
-				"forward": {"iif=eth0 oif=eth2 daddr=192.0.2.17"}},
+			want: map[string][]string{"prerouting": {"iif=eth0 ip4 daddr=203.0.113.5"},
+				"forward": {"iif=eth0 oif=eth2 ip4 daddr=192.0.2.17"}},
 		},
 		{
 			name: "dnat origdest list",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "net", Dest: "svr:192.0.2.17", Proto: "tcp", DPort: config.PortSpec{"80"}, OrigDest: "203.0.113.5,203.0.113.6"},
-			want: map[string][]string{"prerouting": {"iif=eth0 daddr=203.0.113.5", "iif=eth0 daddr=203.0.113.6"},
-				"forward": {"iif=eth0 oif=eth2 daddr=192.0.2.17"}},
+			want: map[string][]string{"prerouting": {"iif=eth0 ip4 daddr=203.0.113.5", "iif=eth0 ip4 daddr=203.0.113.6"},
+				"forward": {"iif=eth0 oif=eth2 ip4 daddr=192.0.2.17"}},
 		},
 		{
 			name: "dnat negated origdest list",
 			rule: config.Rule{Action: config.RuleDNAT, Source: "net", Dest: "svr:192.0.2.17", Proto: "tcp", DPort: config.PortSpec{"80"}, OrigDest: "!203.0.113.5,203.0.113.6"},
-			want: map[string][]string{"prerouting": {"iif=eth0 !daddr=203.0.113.5 !daddr=203.0.113.6"},
-				"forward": {"iif=eth0 oif=eth2 daddr=192.0.2.17"}},
+			want: map[string][]string{"prerouting": {"iif=eth0 ip4 !daddr=203.0.113.5 !daddr=203.0.113.6"},
+				"forward": {"iif=eth0 oif=eth2 ip4 daddr=192.0.2.17"}},
 		},
 		{
 			name: "accept origdest",
 			rule: config.Rule{Action: config.RuleAccept, Source: "net", Dest: "fw", Proto: "tcp", DPort: config.PortSpec{"22"}, OrigDest: "203.0.113.5"},
-			want: map[string][]string{"input": {"iif=eth0 daddr=203.0.113.5"}},
+			want: map[string][]string{"input": {"iif=eth0 ip4 daddr=203.0.113.5"}},
 		},
 		{
 			name: "origdest does not scope interface-less zone",
@@ -2078,7 +2100,7 @@ func TestCompile_CommaZoneLists(t *testing.T) {
 		{
 			name: "accept ipv6 origdest",
 			rule: config.Rule{Action: config.RuleAccept, Source: "net", Dest: "fw", Proto: "tcp", DPort: config.PortSpec{"22"}, OrigDest: "2001:db8::5"},
-			want: map[string][]string{"input": {"iif=eth0 daddr=2001:db8::5"}},
+			want: map[string][]string{"input": {"iif=eth0 ip6 daddr=2001:db8::5"}},
 		},
 		{
 			name:   "blrule zone list",
@@ -2473,7 +2495,7 @@ func TestCompile_RejectPerProto(t *testing.T) {
 }
 
 func TestNegatedAddressList(t *testing.T) {
-	exprs, err := matchDestCIDR("!192.0.2.1,198.51.100.1")
+	exprs, err := matchAddrCIDR("!192.0.2.1,198.51.100.1", false)
 	if err != nil {
 		t.Fatalf("matchDestCIDR error: %v", err)
 	}
@@ -2591,25 +2613,6 @@ func TestCompile_ColonRanges(t *testing.T) {
 	}
 }
 
-func TestMatchOrigDest_FamilyGuard(t *testing.T) {
-	for addr, want := range map[string]byte{
-		"203.0.113.5":               unix.NFPROTO_IPV4,
-		"!203.0.113.0/24,192.0.2.1": unix.NFPROTO_IPV4,
-		"2001:db8::5":               unix.NFPROTO_IPV6,
-	} {
-		e, err := matchOrigDest(addr)
-		if err != nil {
-			t.Fatalf("%s: %v", addr, err)
-		}
-		if m, ok := e[0].(*expr.Meta); !ok || m.Key != expr.MetaKeyNFPROTO || e[1].(*expr.Cmp).Data[0] != want {
-			t.Errorf("%s: missing nfproto %d guard: %v", addr, want, e[:2])
-		}
-	}
-	if _, err := matchOrigDest("!203.0.113.5,2001:db8::5"); err == nil {
-		t.Error("mixed IPv4/IPv6 origdest: want error")
-	}
-}
-
 func TestCompile_OrigDestForwardRejected(t *testing.T) {
 	cfg := &config.Config{
 		Settings:   config.Settings{TableName: "test", AddressFamily: config.FamilyINET},
@@ -2699,7 +2702,7 @@ func TestCompile_ConntrackZones(t *testing.T) {
 		{
 			name: "source and dest addresses",
 			ct:   config.ConntrackRule{Action: config.ConntrackDrop, Source: "net:192.0.2.1,198.51.100.1", Dest: "fw:203.0.113.1"},
-			want: map[string][]string{"raw_prerouting": {"iif=eth0 saddr=192.0.2.1 daddr=203.0.113.1", "iif=eth0 saddr=198.51.100.1 daddr=203.0.113.1"}},
+			want: map[string][]string{"raw_prerouting": {"iif=eth0 ip4 saddr=192.0.2.1 daddr=203.0.113.1", "iif=eth0 ip4 saddr=198.51.100.1 daddr=203.0.113.1"}},
 		},
 		{
 			name: "fw source goes to raw_output with dest oif",
@@ -2709,7 +2712,7 @@ func TestCompile_ConntrackZones(t *testing.T) {
 		{
 			name: "all matches no interface",
 			ct:   config.ConntrackRule{Action: config.ConntrackNoTrack, Source: "all", Dest: "fw:192.0.2.53"},
-			want: map[string][]string{"raw_prerouting": {"daddr=192.0.2.53"}},
+			want: map[string][]string{"raw_prerouting": {"ip4 daddr=192.0.2.53"}},
 		},
 		{
 			name: "interface-less zone fails closed",
@@ -2767,9 +2770,9 @@ func TestCompile_ConntrackZones(t *testing.T) {
 			want: map[string][]string{"raw_output": {"oif=eth1"}},
 		},
 		{
-			name: "negated addresses stay one AND-ed match",
+			name: "negated addresses are one AND-ed match per family",
 			ct:   config.ConntrackRule{Action: config.ConntrackDrop, Source: "net:!192.0.2.1,198.51.100.1"},
-			want: map[string][]string{"raw_prerouting": {"iif=eth0 !saddr=192.0.2.1 !saddr=198.51.100.1"}},
+			want: map[string][]string{"raw_prerouting": {"iif=eth0 ip4 !saddr=192.0.2.1 !saddr=198.51.100.1", "iif=eth0 ip6"}},
 		},
 		{
 			name: "sport",
@@ -2789,7 +2792,7 @@ func TestCompile_ConntrackZones(t *testing.T) {
 		{
 			name: "fw dest zone with address matches daddr",
 			ct:   config.ConntrackRule{Action: config.ConntrackNoTrack, Source: "net", Dest: "fw:192.0.2.1"},
-			want: map[string][]string{"raw_prerouting": {"iif=eth0 daddr=192.0.2.1"}},
+			want: map[string][]string{"raw_prerouting": {"iif=eth0 ip4 daddr=192.0.2.1"}},
 		},
 		{
 			name: "unknown zone fails closed",
@@ -2844,7 +2847,7 @@ func TestCompile_ConntrackZones(t *testing.T) {
 		{
 			name: "dest zone with address matches daddr",
 			ct:   config.ConntrackRule{Action: config.ConntrackNoTrack, Source: "net", Dest: "lan:203.0.113.10"},
-			want: map[string][]string{"raw_prerouting": {"iif=eth0 daddr=203.0.113.10"}},
+			want: map[string][]string{"raw_prerouting": {"iif=eth0 ip4 daddr=203.0.113.10"}},
 		},
 	}
 	for _, tt := range tests {
@@ -2943,7 +2946,7 @@ func TestCompile_ConntrackHelperZones(t *testing.T) {
 		{
 			name: "dest zone with address in prerouting",
 			ct:   config.ConntrackRule{Source: "net", Dest: "lan:203.0.113.10", Proto: "tcp", DPort: config.PortSpec{"21"}},
-			want: map[string][]string{"helper_prerouting": {"iif=eth0 daddr=203.0.113.10"}},
+			want: map[string][]string{"helper_prerouting": {"iif=eth0 ip4 daddr=203.0.113.10"}},
 		},
 		{
 			name:    "dest zone without address is rejected in prerouting",
@@ -3009,7 +3012,7 @@ func TestCompile_AllIncludesFirewallMatches(t *testing.T) {
 		{
 			name: "all address kept on added fw rules",
 			rule: config.Rule{Action: config.RuleAccept, Source: "all:192.0.2.5", Dest: "all"},
-			want: map[string][]string{"input": {"saddr=192.0.2.5"}, "output": {"saddr=192.0.2.5"}, "forward": {"saddr=192.0.2.5"}},
+			want: map[string][]string{"input": {"ip4 saddr=192.0.2.5"}, "output": {"ip4 saddr=192.0.2.5"}, "forward": {"ip4 saddr=192.0.2.5"}},
 		},
 		{
 			name: "dnat with all source skips fw",
@@ -3320,3 +3323,444 @@ func TestCompile_LogLimitSplitsAroundExtrasAndNAT(t *testing.T) {
 		}
 	}
 }
+
+// hostsCfg models a shorewall setup where lan:net is defined by hosts on net's interfaces.
+func hostsCfg(mod func(*config.Config)) *config.Config {
+	cfg := &config.Config{
+		Settings: config.Settings{TableName: "test", AddressFamily: config.FamilyINET},
+		Zones: map[string]config.Zone{
+			"fw": {Type: config.ZoneFirewall}, "net": {Type: config.ZoneIP},
+			"lan": {Type: config.ZoneIP, Parents: []string{"net"}}, "vpn": {Type: config.ZoneIP},
+		},
+		Interfaces: []config.Interface{
+			{Zone: "net", Interface: "wlo1"}, {Zone: "net", Interface: "enp2s0"}, {Zone: "vpn", Interface: "tun0"},
+		},
+		Hosts: []config.Host{
+			{Zone: "lan", Interface: "wlo1", Addresses: []string{"192.0.2.0/24"}},
+			{Zone: "lan", Interface: "enp2s0", Addresses: []string{"198.51.100.0/24"}},
+		},
+		Policy: []config.Policy{
+			{Source: "net", Dest: "all", Action: config.PolicyDrop},
+			{Source: "lan", Dest: "fw", Action: config.PolicyReject},
+			{Source: "all", Dest: "all", Action: config.PolicyReject},
+		},
+		Rules: []config.Rule{
+			{Action: config.RuleAccept, Source: "lan,vpn", Dest: "fw", Proto: "tcp", DPort: config.PortSpec{"6768"}},
+		},
+		PortGroups: make(map[string]config.PortGroup),
+	}
+	if mod != nil {
+		mod(cfg)
+	}
+	return cfg
+}
+
+func describeTagged(state *FirewallState, chain, tag string) []string {
+	var out []string
+	for _, r := range taggedRules(state, chain, tag) {
+		out = append(out, describeRule(r))
+	}
+	return out
+}
+
+func TestCompile_HostsZoneRules(t *testing.T) {
+	var logs bytes.Buffer
+	prev := slog.Default()
+	slog.SetDefault(slog.New(slog.NewTextHandler(&logs, nil)))
+	defer slog.SetDefault(prev)
+
+	state := mustCompile(t, hostsCfg(nil))
+	want := []string{"iif=wlo1 ip4 saddr=192.0.2.0/24", "iif=enp2s0 ip4 saddr=198.51.100.0/24", "iif=tun0"}
+	if got := describeTagged(state, "input", "rule:0"); !reflect.DeepEqual(got, want) {
+		t.Errorf("input rule:0 = %q, want %q", got, want)
+	}
+	if strings.Contains(logs.String(), "skipping") {
+		t.Errorf("unexpected warning:\n%s", logs.String())
+	}
+}
+
+func TestCompile_HostsSubZoneBeforeParent(t *testing.T) {
+	state := mustCompile(t, hostsCfg(nil))
+	want := []string{
+		"iif=wlo1 ip4 !saddr=192.0.2.0/24", "iif=wlo1 ip6",
+		"iif=enp2s0 ip4 !saddr=198.51.100.0/24", "iif=enp2s0 ip6",
+	}
+	if got := describeTagged(state, "input", "policy:0"); !reflect.DeepEqual(got, want) {
+		t.Errorf("net->fw policy = %q, want %q", got, want)
+	}
+	want = []string{"iif=wlo1 ip4 saddr=192.0.2.0/24", "iif=enp2s0 ip4 saddr=198.51.100.0/24"}
+	if got := describeTagged(state, "input", "policy:1"); !reflect.DeepEqual(got, want) {
+		t.Errorf("lan->fw policy = %q, want %q", got, want)
+	}
+	for _, r := range taggedRules(state, "input", "policy:1") {
+		if !slices.ContainsFunc(r.Exprs, func(e expr.Any) bool {
+			m, ok := e.(*expr.Meta)
+			return ok && m.Key == expr.MetaKeyNFPROTO
+		}) {
+			t.Errorf("host match lacks an nfproto guard: %v", describeRule(r))
+		}
+	}
+}
+
+func TestCompile_HostsZoneMatches(t *testing.T) {
+	tests := []struct {
+		name  string
+		mod   func(*config.Config)
+		chain string
+		tag   string
+		want  []string
+	}{
+		{"forward to hosts zone", func(c *config.Config) {
+			c.Rules = []config.Rule{{Action: config.RuleAccept, Source: "vpn", Dest: "lan", Proto: "tcp"}}
+		}, "forward", "rule:0", []string{"iif=tun0 oif=wlo1 ip4 daddr=192.0.2.0/24", "iif=tun0 oif=enp2s0 ip4 daddr=198.51.100.0/24"}},
+		{"rule address prunes non-overlapping hosts", func(c *config.Config) {
+			c.Rules = []config.Rule{{Action: config.RuleAccept, Source: "lan:192.0.2.5", Dest: "fw", Proto: "tcp"}}
+		}, "input", "rule:0", []string{"iif=wlo1 ip4 saddr=192.0.2.0/24 saddr=192.0.2.5"}},
+		{"host exclusions and sub-zone exclusions fall back to the parent", func(c *config.Config) {
+			c.Hosts[1].Exclusions = []string{"198.51.100.7"}
+			c.Rules = []config.Rule{{Action: config.RuleAccept, Source: "net", Dest: "fw", Proto: "tcp"}}
+		}, "input", "rule:0", []string{
+			"iif=wlo1 ip4 !saddr=192.0.2.0/24", "iif=wlo1 ip6",
+			"iif=enp2s0 ip4 !saddr=198.51.100.0/24", "iif=enp2s0 ip6",
+			"iif=enp2s0 ip4 saddr=198.51.100.7",
+		}},
+		{"host exclusion", func(c *config.Config) {
+			c.Hosts[1].Exclusions = []string{"198.51.100.7"}
+		}, "input", "policy:1", []string{"iif=wlo1 ip4 saddr=192.0.2.0/24", "iif=enp2s0 ip4 saddr=198.51.100.0/24 !saddr=198.51.100.7"}},
+		{"DNAT from hosts zone", func(c *config.Config) {
+			c.Rules = []config.Rule{{Action: config.RuleDNAT, Source: "lan", Dest: "vpn:203.0.113.10", Proto: "tcp", DPort: config.PortSpec{"80"}}}
+		}, "prerouting", "rule:0", []string{"iif=wlo1 ip4 saddr=192.0.2.0/24", "iif=enp2s0 ip4 saddr=198.51.100.0/24"}},
+		{"conntrack from hosts zone", func(c *config.Config) {
+			c.Conntrack = []config.ConntrackRule{{Action: config.ConntrackNoTrack, Source: "lan", Proto: "udp"}}
+		}, "raw_prerouting", "conntrack:0:raw_prerouting", []string{"iif=wlo1 ip4 saddr=192.0.2.0/24", "iif=enp2s0 ip4 saddr=198.51.100.0/24"}},
+		{"blrule from hosts zone", func(c *config.Config) {
+			c.Blrules = []config.BlruleRule{{Action: config.BlruleDrop, Source: "lan", Dest: "all"}}
+		}, "input", "blrule:0", []string{"iif=wlo1 ip4 saddr=192.0.2.0/24", "iif=enp2s0 ip4 saddr=198.51.100.0/24"}},
+		{"all expansion includes hosts zone", func(c *config.Config) {
+			c.Rules = []config.Rule{{Action: config.RuleAccept, Source: "all!net,vpn", Dest: "fw", Proto: "tcp"}}
+		}, "input", "rule:0", []string{"iif=wlo1 ip4 saddr=192.0.2.0/24", "iif=enp2s0 ip4 saddr=198.51.100.0/24"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			state := mustCompile(t, hostsCfg(tt.mod))
+			if got := describeTagged(state, tt.chain, tt.tag); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("%s %s = %q, want %q", tt.chain, tt.tag, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestCompile_IntraZoneMultiInterface(t *testing.T) {
+	tests := []struct {
+		name   string
+		policy []config.Policy
+		tag    string
+		want   []string
+	}{
+		{
+			name:   "implicit accept between distinct interfaces",
+			policy: []config.Policy{{Source: "all", Dest: "all", Action: config.PolicyDrop}},
+			tag:    "intra:lxd",
+			want:   []string{"iif=lxdbr0 oif=docker0", "iif=lxdbr0 oif=br-", "iif=docker0 oif=lxdbr0", "iif=docker0 oif=br-", "iif=br- oif=lxdbr0", "iif=br- oif=docker0"},
+		},
+		{
+			name:   "explicit zone policy overrides",
+			policy: []config.Policy{{Source: "lxd", Dest: "lxd", Action: config.PolicyDrop, Log: "info"}, {Source: "all", Dest: "all", Action: config.PolicyDrop}},
+			tag:    "policy:0",
+			want:   []string{"iif=lxdbr0 oif=docker0", "iif=lxdbr0 oif=br-", "iif=docker0 oif=lxdbr0", "iif=docker0 oif=br-", "iif=br- oif=lxdbr0", "iif=br- oif=docker0"},
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			cfg := &config.Config{
+				Settings: config.Settings{TableName: "test", AddressFamily: config.FamilyINET},
+				Zones: map[string]config.Zone{
+					"fw":  {Type: config.ZoneFirewall},
+					"net": {Type: config.ZoneIP},
+					"lxd": {Type: config.ZoneIP},
+				},
+				Interfaces: []config.Interface{
+					{Zone: "net", Interface: "eth0"},
+					{Zone: "lxd", Interface: "lxdbr0"},
+					{Zone: "lxd", Interface: "docker0"},
+					{Zone: "lxd", Interface: "br-+"},
+				},
+				Policy:     tc.policy,
+				PortGroups: map[string]config.PortGroup{},
+			}
+			state, err := NewCompiler(cfg).Compile()
+			if err != nil {
+				t.Fatalf("Compile() error: %v", err)
+			}
+			var got, all []string
+			for _, r := range state.Rules["forward"] {
+				if r.Tag == tc.tag {
+					got = append(got, describeRule(r))
+				}
+				if strings.HasPrefix(r.Tag, "intra:") {
+					all = append(all, r.Tag)
+				}
+			}
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("%s rules = %q, want %q", tc.tag, got, tc.want)
+			}
+			if tc.tag != "intra:lxd" && len(all) != 0 {
+				t.Errorf("explicit policy must replace implicit accept, got %q", all)
+			}
+			last := taggedRules(state, "forward", tc.tag)
+			if len(last) == 0 {
+				return
+			}
+			if v, ok := last[0].Exprs[len(last[0].Exprs)-1].(*expr.Verdict); !ok || (tc.tag == "intra:lxd") != (v.Kind == expr.VerdictAccept) {
+				t.Errorf("%s verdict = %#v", tc.tag, last[0].Exprs[len(last[0].Exprs)-1])
+			}
+		})
+	}
+}
+
+func TestCompile_HostsAddressMatchesFamilyGuarded(t *testing.T) {
+	state := mustCompile(t, hostsCfg(func(c *config.Config) {
+		c.Hosts[0].Addresses = append(c.Hosts[0].Addresses, "2001:db8::/64")
+		c.Hosts[0].Exclusions = []string{"192.0.2.9"}
+	}))
+	want := []string{
+		"iif=wlo1 ip4 !saddr=192.0.2.0/24", "iif=wlo1 ip6 !saddr=2001:db8::/64",
+		"iif=wlo1 ip4 saddr=192.0.2.9",
+		"iif=enp2s0 ip4 !saddr=198.51.100.0/24", "iif=enp2s0 ip6",
+	}
+	if got := describeTagged(state, "input", "policy:0"); !reflect.DeepEqual(got, want) {
+		t.Errorf("net->fw DROP policy = %q, want %q", got, want)
+	}
+	want = []string{
+		"iif=wlo1 ip4 saddr=192.0.2.0/24 !saddr=192.0.2.9", "iif=wlo1 ip6 saddr=2001:db8::/64",
+		"iif=enp2s0 ip4 saddr=198.51.100.0/24",
+	}
+	if got := describeTagged(state, "input", "policy:1"); !reflect.DeepEqual(got, want) {
+		t.Errorf("lan->fw policy = %q, want %q", got, want)
+	}
+	for chain, rules := range state.Rules {
+		for _, r := range rules {
+			var fam byte
+			for i, e := range r.Exprs {
+				if m, ok := e.(*expr.Meta); ok && m.Key == expr.MetaKeyNFPROTO {
+					fam = r.Exprs[i+1].(*expr.Cmp).Data[0]
+				}
+				p, ok := e.(*expr.Payload)
+				if !ok || p.Base != expr.PayloadBaseNetworkHeader {
+					continue
+				}
+				if p.Len == 4 && fam != unix.NFPROTO_IPV4 || p.Len == 16 && fam != unix.NFPROTO_IPV6 {
+					t.Errorf("%s %s: %d-byte address compare without its family guard: %s", chain, r.Tag, p.Len, describeRule(r))
+				}
+			}
+		}
+	}
+}
+
+func TestCompile_FirewallSelfPolicySkipped(t *testing.T) {
+	for _, action := range []config.PolicyAction{config.PolicyAccept, config.PolicyDrop} {
+		t.Run(string(action), func(t *testing.T) {
+			state := mustCompile(t, listCfg(func(c *config.Config) {
+				c.Policy = []config.Policy{
+					{Source: "fw", Dest: "fw", Action: action},
+					{Source: "net", Dest: "fw", Action: config.PolicyDrop, Log: "info"},
+				}
+			}))
+			for _, chain := range []string{"input", "output", "forward"} {
+				if got := taggedRules(state, chain, "policy:0"); len(got) != 0 {
+					t.Errorf("fw->fw emitted %d rules in %s", len(got), chain)
+				}
+			}
+			got := taggedRules(state, "input", "policy:1")
+			if len(got) != 1 || describeRule(got[0]) != "iif=eth0" {
+				t.Errorf("net->fw input rules = %d, want one scoped to eth0", len(got))
+			}
+		})
+	}
+}
+
+func TestCompile_DestPlusOverridesIntraZone(t *testing.T) {
+	state := mustCompile(t, listCfg(func(c *config.Config) {
+		c.Zones["lxd"] = config.Zone{Type: config.ZoneIP}
+		c.Interfaces = append(c.Interfaces, config.Interface{Zone: "lxd", Interface: "lxdbr0"}, config.Interface{Zone: "lxd", Interface: "docker0"})
+		c.Policy = []config.Policy{{Source: "lxd", Dest: "all+", Action: config.PolicyDrop}}
+	}))
+	if got := taggedRules(state, "forward", "intra:lxd"); len(got) != 0 {
+		t.Errorf("lxd all+ must override implicit intra-zone accept, got %d rules", len(got))
+	}
+	if got := taggedRules(state, "forward", "policy:0"); len(got) == 0 {
+		t.Error("lxd all+ emitted no forward rules")
+	}
+}
+
+func TestCompile_HostsIntraZone(t *testing.T) {
+	state := mustCompile(t, hostsCfg(nil))
+	want := []string{
+		"iif=wlo1 ip4 saddr=192.0.2.0/24 oif=enp2s0 daddr=198.51.100.0/24",
+		"iif=enp2s0 ip4 saddr=198.51.100.0/24 oif=wlo1 daddr=192.0.2.0/24",
+	}
+	if got := describeTagged(state, "forward", "intra:lan"); !reflect.DeepEqual(got, want) {
+		t.Errorf("lan intra = %q, want %q", got, want)
+	}
+	want = []string{
+		"iif=wlo1 ip4 !saddr=192.0.2.0/24 oif=enp2s0 !daddr=198.51.100.0/24",
+		"iif=wlo1 ip6 oif=enp2s0",
+		"iif=enp2s0 ip4 !saddr=198.51.100.0/24 oif=wlo1 !daddr=192.0.2.0/24",
+		"iif=enp2s0 ip6 oif=wlo1",
+	}
+	if got := describeTagged(state, "forward", "intra:net"); !reflect.DeepEqual(got, want) {
+		t.Errorf("net intra = %q, want %q", got, want)
+	}
+
+	state = mustCompile(t, hostsCfg(func(c *config.Config) {
+		c.Policy = append([]config.Policy{{Source: "lan", Dest: "lan", Action: config.PolicyDrop}}, c.Policy...)
+	}))
+	if got := describeTagged(state, "forward", "intra:lan"); len(got) != 0 {
+		t.Errorf("explicit lan lan policy must replace implicit accept, got %q", got)
+	}
+	want = []string{
+		"iif=wlo1 ip4 saddr=192.0.2.0/24 oif=enp2s0 daddr=198.51.100.0/24",
+		"iif=enp2s0 ip4 saddr=198.51.100.0/24 oif=wlo1 daddr=192.0.2.0/24",
+	}
+	if got := describeTagged(state, "forward", "policy:0"); !reflect.DeepEqual(got, want) {
+		t.Errorf("lan lan policy = %q, want %q", got, want)
+	}
+}
+
+func TestCompile_HostsRouteBack(t *testing.T) {
+	sameIface := func(routeback bool) func(*config.Config) {
+		return func(c *config.Config) {
+			c.Hosts = []config.Host{
+				{Zone: "lan", Interface: "wlo1", Addresses: []string{"192.0.2.0/24"}, Options: config.HostOptions{RouteBack: routeback}},
+				{Zone: "lan", Interface: "wlo1", Addresses: []string{"198.51.100.0/24"}},
+			}
+		}
+	}
+	if got := describeTagged(mustCompile(t, hostsCfg(sameIface(false))), "forward", "intra:lan"); len(got) != 0 {
+		t.Errorf("same-interface hosts without routeback = %q, want none", got)
+	}
+	want := []string{"iif=wlo1 ip4 saddr=192.0.2.0/24 oif=wlo1 daddr=192.0.2.0/24"}
+	if got := describeTagged(mustCompile(t, hostsCfg(sameIface(true))), "forward", "intra:lan"); !reflect.DeepEqual(got, want) {
+		t.Errorf("routeback hosts intra = %q, want %q", got, want)
+	}
+
+	state := mustCompile(t, hostsCfg(func(c *config.Config) {
+		sameIface(true)(c)
+		c.Policy = append([]config.Policy{{Source: "lan", Dest: "lan", Action: config.PolicyDrop}}, c.Policy...)
+	}))
+	if got := describeTagged(state, "forward", "policy:0"); !reflect.DeepEqual(got, want) {
+		t.Errorf("routeback hosts lan lan policy = %q, want %q", got, want)
+	}
+}
+
+func TestCompile_LimitNegatedAddrPerTableFamily(t *testing.T) {
+	for _, tt := range []struct {
+		name    string
+		family  config.AddressFamily
+		source  string
+		wantErr bool
+	}{
+		{"ip v4 negation", config.FamilyIP, "net:!192.0.2.1", false},
+		{"ip v6 negation", config.FamilyIP, "net:!2001:db8::1", false},
+		{"ip mixed negation", config.FamilyIP, "net:!192.0.2.1,2001:db8::1", false},
+		{"ip6 v6 negation", config.FamilyIP6, "net:!2001:db8::1", false},
+		{"ip6 v4 negation", config.FamilyIP6, "net:!192.0.2.1", false},
+		{"inet v4 negation", config.FamilyINET, "net:!192.0.2.1", true},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := &config.Config{
+				Settings:   config.Settings{TableName: "test", AddressFamily: tt.family},
+				Zones:      map[string]config.Zone{"fw": {Type: config.ZoneFirewall}, "net": {Type: config.ZoneIP}},
+				Interfaces: []config.Interface{{Zone: "net", Interface: "eth0"}},
+				Rules:      []config.Rule{{Action: config.RuleAccept, Source: tt.source, Dest: "fw", Proto: "tcp", DPort: config.PortSpec{"22"}, RateLimit: "10/sec"}},
+				PortGroups: make(map[string]config.PortGroup),
+			}
+			state, err := NewCompiler(cfg).Compile()
+			if tt.wantErr {
+				if err == nil || !strings.Contains(err.Error(), "negated address in an inet table") {
+					t.Fatalf("Compile() error = %v, want negated-address inet error", err)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Compile() error: %v", err)
+			}
+			n := 0
+			for _, r := range state.Rules["input"] {
+				if r.Tag == "rule:0" {
+					n++
+				}
+			}
+			if n != 1 {
+				t.Errorf("got %d rule:0 rules, want 1", n)
+			}
+		})
+	}
+}
+
+func TestCompile_WildcardParentExcludesSubZoneHosts(t *testing.T) {
+	cfg := &config.Config{
+		Settings: config.Settings{TableName: "test", AddressFamily: config.FamilyINET},
+		Zones: map[string]config.Zone{
+			"fw": {Type: config.ZoneFirewall}, "net": {Type: config.ZoneIP},
+			"lan": {Type: config.ZoneIP, Parents: []string{"net"}}, "lxd": {Type: config.ZoneIP},
+		},
+		Interfaces: []config.Interface{
+			{Zone: "net", Interface: "enp+"}, {Zone: "net", Interface: "wlo1"}, {Zone: "lxd", Interface: "lxdbr0"},
+		},
+		Hosts: []config.Host{
+			{Zone: "lan", Interface: "enp2s0", Addresses: []string{"192.0.2.0/24"}},
+			{Zone: "lan", Interface: "enp4+", Addresses: []string{"203.0.113.0/24"}},
+			{Zone: "lan", Interface: "wlo1", Addresses: []string{"198.51.100.0/24"}},
+		},
+		Policy: []config.Policy{
+			{Source: "lxd", Dest: "net", Action: config.PolicyAccept},
+			{Source: "fw", Dest: "net", Action: config.PolicyDrop},
+			{Source: "net", Dest: "all", Action: config.PolicyDrop},
+			{Source: "all", Dest: "all", Action: config.PolicyReject},
+		},
+		PortGroups: make(map[string]config.PortGroup),
+	}
+	state := mustCompile(t, cfg)
+	for _, tt := range []struct{ chain, tag, dir string }{
+		{"forward", "policy:0", "iif=lxdbr0 oif"}, {"output", "policy:1", "oif"}, {"input", "policy:2", "iif"},
+	} {
+		d, a := tt.dir, "daddr"
+		if tt.chain == "input" {
+			a = "saddr"
+		}
+		want := []string{
+			d + "=enp " + d[len(d)-3:] + "!=enp2s0 " + d[len(d)-3:] + "!=enp4",
+			d + "=enp2s0 ip4 !" + a + "=192.0.2.0/24", d + "=enp2s0 ip6",
+			d + "=enp4 ip4 !" + a + "=203.0.113.0/24", d + "=enp4 ip6",
+			d + "=wlo1 ip4 !" + a + "=198.51.100.0/24", d + "=wlo1 ip6",
+		}
+		if got := describeTagged(state, tt.chain, tt.tag); !reflect.DeepEqual(got, want) {
+			t.Errorf("%s %s = %q, want %q", tt.chain, tt.tag, got, want)
+		}
+	}
+	for chain, want := range map[string]string{
+		"forward": "iif=lxdbr0 oif=enp2s0 ip4 daddr=192.0.2.0/24",
+		"output":  "oif=enp2s0 ip4 daddr=192.0.2.0/24",
+		"input":   "iif=enp2s0 ip4 saddr=192.0.2.0/24",
+	} {
+		if got := describeTagged(state, chain, "policy:3"); !slices.Contains(got, want) {
+			t.Errorf("%s policy:3 (lan reject) = %q, want it to contain %q", chain, got, want)
+		}
+	}
+}
+
+func TestIfaceCovers(t *testing.T) {
+	for _, tt := range []struct {
+		a, b string
+		want bool
+	}{
+		{"enp2s0", "enp2s0", true}, {"enp2s0", "enp3s0", false},
+		{"enp+", "enp2s0", true}, {"enp2s0", "enp+", false}, {"enp+", "wlo1", false},
+		{"en+", "enp+", true}, {"enp+", "en+", false}, {"enp+", "eno+", false}, {"enp+", "enp", true},
+	} {
+		if got := ifaceCovers(tt.a, tt.b); got != tt.want {
+			t.Errorf("ifaceCovers(%q, %q) = %v, want %v", tt.a, tt.b, got, tt.want)
+		}
+	}
+}

internal/nftables/guards_test.go

@@ -0,0 +1,239 @@
+package nftables
+
+import (
+	"os"
+	"os/exec"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/google/nftables/expr"
+	"golang.org/x/sys/unix"
+
+	"git.unkin.net/unkin/tomswall/internal/config"
+)
+
+func guardCfg(af config.AddressFamily) *config.Config {
+	return hostsCfg(func(c *config.Config) {
+		c.Settings.AddressFamily = af
+		c.Hosts[0].Addresses = append(c.Hosts[0].Addresses, "2001:db8::/64")
+		c.Hosts[0].Exclusions = []string{"192.0.2.9", "2001:db8::9"}
+		c.Interfaces[0].Options.NoSmurfs = true
+		c.Rules = append(c.Rules,
+			config.Rule{Action: config.RuleDrop, Source: "net:203.0.113.7", Dest: "lan:192.0.2.5"},
+			config.Rule{Action: config.RuleDrop, Source: "net:2001:db8:1::7", Dest: "lan:2001:db8::5"},
+			config.Rule{Action: config.RuleDrop, Source: "vpn", Dest: "net:!192.0.2.1"},
+			config.Rule{Action: config.RuleDrop, Source: "vpn", Dest: "net:!192.0.2.1,2001:db8::1"},
+			config.Rule{Action: config.RuleDrop, Source: "vpn:203.0.113.7", Dest: "net:!2001:db8::5"},
+			config.Rule{Action: config.RuleDNAT, Source: "vpn", Dest: "lan:192.0.2.10", Proto: "tcp",
+				DPort: config.PortSpec{"80"}, OrigDest: "!203.0.113.5,2001:db8::5"},
+			config.Rule{Action: config.RuleDrop, Source: "vpn:192.0.2.77,2001:db8:7::7", Dest: "fw"})
+		c.Blrules = []config.BlruleRule{{Action: config.BlruleDrop, Source: "vpn:!192.0.2.1,2001:db8::1", Dest: "fw"}}
+		c.SNAT = []config.SNATRule{
+			{Action: config.SNATMasquerade, Dest: "wlo1", Source: "!192.0.2.0/24,2001:db8::/48"},
+			{Action: config.SNATAddress, Address: "203.0.113.1", Dest: "wlo1", Source: "!192.0.2.9,2001:db8::9"},
+			{Action: config.SNATAddress, Address: "203.0.113.1", Dest: "wlo1", Source: "2001:db8::/48"},
+		}
+		c.Tunnels = []config.Tunnel{{Type: "gre", Zone: "vpn", Gateways: []string{"203.0.113.50", "2001:db8:5::1"}}}
+		c.StaticNAT = []config.StaticNAT{
+			{External: "203.0.113.60", Interface: "wlo1", Internal: "192.0.2.60"},
+			{External: "2001:db8:6::1", Interface: "wlo1", Internal: "2001:db8::60"},
+		}
+	})
+}
+
+func TestCompile_FamilyGuardsDecodable(t *testing.T) {
+	addrLen := map[config.AddressFamily]uint32{config.FamilyIP: 4, config.FamilyIP6: 16}
+	for _, af := range []config.AddressFamily{config.FamilyINET, config.FamilyIP, config.FamilyIP6} {
+		t.Run(string(af), func(t *testing.T) {
+			for chain, rules := range mustCompile(t, guardCfg(af)).Rules {
+				for _, r := range rules {
+					guards, l3 := 0, false
+					for i, e := range r.Exprs {
+						if nfprotoGuard(r.Exprs, i) != 0 {
+							guards++
+							if l3 {
+								t.Errorf("%s %s: guard after a network payload: %s", chain, r.Tag, describeRule(r))
+							}
+						}
+						if p, ok := e.(*expr.Payload); ok && p.Base == expr.PayloadBaseNetworkHeader {
+							l3 = true
+							if n := addrLen[af]; n != 0 && (p.Len == 4 || p.Len == 16) && p.Len != n {
+								t.Errorf("%s %s: other-family address in %s table: %s", chain, r.Tag, af, describeRule(r))
+							}
+						}
+					}
+					if max := map[bool]int{true: 1, false: 0}[af == config.FamilyINET]; guards > max {
+						t.Errorf("%s %s: %d family guards in %s table: %s", chain, r.Tag, guards, af, describeRule(r))
+					}
+				}
+			}
+		})
+	}
+}
+
+func TestCompile_FamilyGuardsPerFamily(t *testing.T) {
+	state := mustCompile(t, guardCfg(config.FamilyINET))
+	for _, tt := range []struct {
+		chain, tag string
+		want       []string
+	}{
+		{"forward", "rule:3", []string{
+			"iif=tun0 oif=wlo1 ip4 !daddr=192.0.2.0/24 !daddr=192.0.2.1",
+			"iif=tun0 oif=wlo1 ip4 daddr=192.0.2.9 !daddr=192.0.2.1",
+			"iif=tun0 oif=enp2s0 ip4 !daddr=198.51.100.0/24 !daddr=192.0.2.1",
+			"iif=tun0 oif=wlo1 ip6 !daddr=2001:db8::/64",
+			"iif=tun0 oif=wlo1 ip6 daddr=2001:db8::9",
+			"iif=tun0 oif=enp2s0 ip6",
+		}},
+		{"forward", "rule:4", []string{
+			"iif=tun0 oif=wlo1 ip4 !daddr=192.0.2.0/24 !daddr=192.0.2.1",
+			"iif=tun0 oif=wlo1 ip4 daddr=192.0.2.9 !daddr=192.0.2.1",
+			"iif=tun0 oif=enp2s0 ip4 !daddr=198.51.100.0/24 !daddr=192.0.2.1",
+			"iif=tun0 oif=wlo1 ip6 !daddr=2001:db8::/64 !daddr=2001:db8::1",
+			"iif=tun0 oif=wlo1 ip6 daddr=2001:db8::9 !daddr=2001:db8::1",
+			"iif=tun0 oif=enp2s0 ip6 !daddr=2001:db8::1",
+		}},
+		{"forward", "rule:5", []string{
+			"iif=tun0 oif=wlo1 ip4 !daddr=192.0.2.0/24 saddr=203.0.113.7",
+			"iif=tun0 oif=wlo1 ip4 daddr=192.0.2.9 saddr=203.0.113.7",
+			"iif=tun0 oif=enp2s0 ip4 !daddr=198.51.100.0/24 saddr=203.0.113.7",
+		}},
+		{"prerouting", "rule:6", []string{"iif=tun0 ip4 !daddr=203.0.113.5"}},
+		{"forward", "rule:6:accept", []string{"iif=tun0 oif=wlo1 ip4 daddr=192.0.2.0/24 !daddr=192.0.2.9 daddr=192.0.2.10"}},
+		{"input", "rule:7", []string{"iif=tun0 ip4 saddr=192.0.2.77", "iif=tun0 ip6 saddr=2001:db8:7::7"}},
+		{"input", "blrule:0", []string{"iif=tun0 ip4 !saddr=192.0.2.1", "iif=tun0 ip6 !saddr=2001:db8::1"}},
+		{"postrouting", "snat:0", []string{"oif=wlo1 ip4 !saddr=192.0.2.0/24", "oif=wlo1 ip6 !saddr=2001:db8::/48"}},
+		{"postrouting", "snat:1", []string{"oif=wlo1 ip4 !saddr=192.0.2.9"}},
+		{"postrouting", "snat:2", nil},
+		{"input", "tunnel:0", []string{"ip4 saddr=203.0.113.50", "ip6 saddr=2001:db8:5::1"}},
+		{"prerouting", "staticnat:dnat:0", []string{"iif=wlo1 ip4 daddr=203.0.113.60"}},
+		{"postrouting", "staticnat:snat:1", []string{"oif=wlo1 ip6 saddr=2001:db8::60"}},
+	} {
+		if got := describeTagged(state, tt.chain, tt.tag); !reflect.DeepEqual(got, tt.want) {
+			t.Errorf("%s %s = %q, want %q", tt.chain, tt.tag, got, tt.want)
+		}
+	}
+}
+
+// TestCompile_NegatedV4DropKeepsV6 checks a single-family table keeps its family's half of a
+// negated DROP: "everything except 192.0.2.1" still drops all IPv6.
+func TestCompile_NegatedV4DropKeepsV6(t *testing.T) {
+	for af, want := range map[config.AddressFamily][]string{
+		config.FamilyIP:  {"iif=tun0 oif=wlo1 !daddr=192.0.2.0/24 !daddr=192.0.2.1", "iif=tun0 oif=wlo1 daddr=192.0.2.9 !daddr=192.0.2.1", "iif=tun0 oif=enp2s0 !daddr=198.51.100.0/24 !daddr=192.0.2.1"},
+		config.FamilyIP6: {"iif=tun0 oif=wlo1 !daddr=2001:db8::/64", "iif=tun0 oif=wlo1 daddr=2001:db8::9", "iif=tun0 oif=enp2s0"},
+	} {
+		if got := describeTagged(mustCompile(t, guardCfg(af)), "forward", "rule:3"); !reflect.DeepEqual(got, want) {
+			t.Errorf("%s rule:3 = %q, want %q", af, got, want)
+		}
+	}
+}
+
+func TestSplitAddrs(t *testing.T) {
+	for in, want := range map[string][]string{
+		"":                                       {""},
+		"192.0.2.1,2001:db8::1":                  {"192.0.2.1", "2001:db8::1"},
+		"!192.0.2.1":                             {"!192.0.2.1", "::/0"},
+		"!2001:db8::1":                           {"0.0.0.0/0", "!2001:db8::1"},
+		"!192.0.2.1,2001:db8::1,198.51.100.0/24": {"!192.0.2.1,198.51.100.0/24", "!2001:db8::1"},
+	} {
+		if got := splitAddrs(in); !reflect.DeepEqual(got, want) {
+			t.Errorf("splitAddrs(%q) = %q, want %q", in, got, want)
+		}
+	}
+}
+
+func TestMatchGuardedCIDR(t *testing.T) {
+	for in, want := range map[string]string{
+		"192.0.2.1":                  "ip4 saddr=192.0.2.1",
+		"2001:db8::/48":              "ip6 saddr=2001:db8::/48",
+		"!192.0.2.1,198.51.100.0/24": "ip4 !saddr=192.0.2.1 !saddr=198.51.100.0/24",
+		"!2001:db8::1":               "ip6 !saddr=2001:db8::1",
+		"0.0.0.0/0":                  "ip4",
+		"::/0":                       "ip6",
+	} {
+		e, err := matchSourceCIDR(in)
+		if err != nil {
+			t.Fatalf("%s: %v", in, err)
+		}
+		if got := describeRule(ManagedRule{Exprs: e}); got != want {
+			t.Errorf("matchSourceCIDR(%q) = %q, want %q", in, got, want)
+		}
+	}
+	if e, _ := matchDestCIDR("!2001:db8::5"); describeRule(ManagedRule{Exprs: e}) != "ip6 !daddr=2001:db8::5" {
+		t.Errorf("matchDestCIDR(!2001:db8::5) = %q", describeRule(ManagedRule{Exprs: e}))
+	}
+	if _, err := matchSourceCIDR("!nonsense"); err == nil {
+		t.Error("invalid negated address: want error")
+	}
+}
+
+func TestFamilyGuards(t *testing.T) {
+	v4, _ := matchSourceCIDR("192.0.2.1")
+	v6, _ := matchDestCIDR("2001:db8::1")
+	both, _ := matchDestCIDR("198.51.100.1")
+	state := func(e ...[]expr.Any) *FirewallState {
+		var r []expr.Any
+		for _, x := range e {
+			r = append(r, x...)
+		}
+		return &FirewallState{Rules: map[string][]ManagedRule{"input": {{Exprs: r, Tag: "t"}}}}
+	}
+	s := state(v4, both)
+	if err := familyGuards(s, config.FamilyINET); err != nil || describeRule(s.Rules["input"][0]) != "ip4 saddr=192.0.2.1 daddr=198.51.100.1" {
+		t.Errorf("same-family guards not merged: %v %q", err, describeRule(s.Rules["input"][0]))
+	}
+	if err := familyGuards(state(v4, v6), config.FamilyINET); err == nil || !strings.Contains(err.Error(), "conflicting") {
+		t.Errorf("conflicting guards: want error, got %v", err)
+	}
+	s = state(v6)
+	if err := familyGuards(s, config.FamilyIP); err != nil || len(s.Rules["input"]) != 0 {
+		t.Errorf("ip table must drop IPv6 rules: %v %v", err, s.Rules["input"])
+	}
+	s = state(v6)
+	if err := familyGuards(s, config.FamilyIP6); err != nil || describeRule(s.Rules["input"][0]) != "daddr=2001:db8::1" {
+		t.Errorf("ip6 table must strip the guard: %v %q", err, describeRule(s.Rules["input"][0]))
+	}
+	if !famsAgree(0, unix.NFPROTO_IPV4, 0, unix.NFPROTO_IPV4) || famsAgree(unix.NFPROTO_IPV4, 0, unix.NFPROTO_IPV6) {
+		t.Error("famsAgree")
+	}
+}
+
+// TestNetnsNftListDecodes applies each family in a fresh user+net namespace and requires
+// nft(8) to list the ruleset and a second plan to be empty. Needs unshare and nft.
+func TestNetnsNftListDecodes(t *testing.T) {
+	if af := os.Getenv("TOMSWALL_NETNS_CHILD"); af != "" {
+		netnsChild(t, config.AddressFamily(af))
+		return
+	}
+	if os.Getenv("TOMSWALL_NETNS_TEST") == "" {
+		t.Skip("set TOMSWALL_NETNS_TEST=1 to run (needs unshare and nft)")
+	}
+	for _, af := range []config.AddressFamily{config.FamilyINET, config.FamilyIP, config.FamilyIP6} {
+		cmd := exec.Command("unshare", "-rn", os.Args[0], "-test.run=^TestNetnsNftListDecodes$", "-test.v")
+		cmd.Env = append(os.Environ(), "TOMSWALL_NETNS_CHILD="+string(af))
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Errorf("%s: %v\n%s", af, err, out)
+		}
+	}
+}
+
+func netnsChild(t *testing.T, af config.AddressFamily) {
+	e, err := NewEngine(guardCfg(af))
+	if err != nil {
+		t.Fatal(err)
+	}
+	cs, err := e.Plan()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := e.Apply(cs); err != nil {
+		t.Fatal(err)
+	}
+	if out, err := exec.Command("nft", "list", "ruleset").CombinedOutput(); err != nil {
+		t.Fatalf("nft list ruleset: %v\n%s", err, out)
+	}
+	if cs, err = e.Plan(); err != nil || len(cs.Add)+len(cs.Remove) != 0 {
+		t.Fatalf("second plan not empty: %d add, %d remove, err %v", len(cs.Add), len(cs.Remove), err)
+	}
+}

internal/shorewall/convert.go

@@ -248,6 +248,9 @@ func convertInterfaces(dir string, cfg *config.Config, params map[string]string)
 	for _, row := range rows {
 		zone := subst(field(row, 0), params)
 		iface := subst(field(row, 1), params)
+		if isDash(zone) {
+			zone = ""
+		}
 
 		intf := config.Interface{
 			Zone:      zone,
@@ -392,12 +395,14 @@ func convertHosts(dir string, cfg *config.Config, params map[string]string) erro
 		zone := subst(field(row, 0), params)
 		hostDef := subst(field(row, 1), params)
 
+		hostDef, excl, _ := strings.Cut(hostDef, "!")
 		iface, addrs := splitHostDef(hostDef)
 
 		host := config.Host{
-			Zone:      zone,
-			Interface: iface,
-			Addresses: addrs,
+			Zone:       zone,
+			Interface:  iface,
+			Addresses:  addrs,
+			Exclusions: splitAddrList(excl),
 		}
 
 		optsStr := subst(field(row, 2), params)
@@ -415,16 +420,19 @@ func splitHostDef(s string) (string, []string) {
 	if idx < 0 {
 		return s, nil
 	}
-	iface := s[:idx]
-	addrPart := s[idx+1:]
+	return s[:idx], splitAddrList(s[idx+1:])
+}
+
+// splitAddrList splits a comma address list, unwrapping shorewall6 [addr]/len brackets.
+func splitAddrList(s string) []string {
 	var addrs []string
-	for _, a := range strings.Split(addrPart, ",") {
-		a = strings.TrimSpace(a)
+	for _, a := range strings.Split(s, ",") {
+		a = strings.NewReplacer("[", "", "]", "").Replace(strings.TrimSpace(a))
 		if a != "" {
 			addrs = append(addrs, a)
 		}
 	}
-	return iface, addrs
+	return addrs
 }
 
 func parseHostOptions(s string) config.HostOptions {

internal/shorewall/convert_test.go

@@ -3,6 +3,7 @@ package shorewall
 import (
 	"os"
 	"path/filepath"
+	"reflect"
 	"testing"
 
 	"git.unkin.net/unkin/tomswall/internal/config"
@@ -776,3 +777,30 @@ func TestConvert_LogLimit(t *testing.T) {
 		}
 	}
 }
+
+func TestConvert_HostsExclusions(t *testing.T) {
+	dir := minimalShorewallDir(t)
+	writeFile(t, dir, "interfaces", `
+net eth0
+- eth1
+`)
+	writeFile(t, dir, "hosts", `
+loc eth0:192.0.2.0/24,198.51.100.0/24!192.0.2.7,192.0.2.8 routeback
+loc eth1:[2001:db8::]/64
+`)
+	cfg, err := Convert(dir)
+	if err != nil {
+		t.Fatalf("Convert: %v", err)
+	}
+	want := []config.Host{
+		{Zone: "loc", Interface: "eth0", Addresses: []string{"192.0.2.0/24", "198.51.100.0/24"},
+			Exclusions: []string{"192.0.2.7", "192.0.2.8"}, Options: config.HostOptions{RouteBack: true}},
+		{Zone: "loc", Interface: "eth1", Addresses: []string{"2001:db8::/64"}},
+	}
+	if !reflect.DeepEqual(cfg.Hosts, want) {
+		t.Errorf("hosts = %+v, want %+v", cfg.Hosts, want)
+	}
+	if err := cfg.Validate(); err != nil {
+		t.Errorf("Validate: %v", err)
+	}
+}