// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package router import ( "errors" "fmt" "math/rand" "sort" "strings" "testing" "github.com/google/go-cmp/cmp" "inet.af/netaddr" ) func mustCIDR(s string) netaddr.IPPrefix { pfx, err := netaddr.ParseIPPrefix(s) if err != nil { panic(err) } return pfx } func mustCIDRs(ss ...string) []netaddr.IPPrefix { var ret []netaddr.IPPrefix for _, s := range ss { ret = append(ret, mustCIDR(s)) } return ret } func TestRouterStates(t *testing.T) { basic := ` ip rule add -4 pref 5210 fwmark 0x80000 table main ip rule add -4 pref 5230 fwmark 0x80000 table default ip rule add -4 pref 5250 fwmark 0x80000 type unreachable ip rule add -4 pref 5270 table 52 ip rule add -6 pref 5210 fwmark 0x80000 table main ip rule add -6 pref 5230 fwmark 0x80000 table default ip rule add -6 pref 5250 fwmark 0x80000 type unreachable ip rule add -6 pref 5270 table 52 ` states := []struct { name string in *Config want string }{ { name: "no config", in: nil, want: ` up` + basic, }, { name: "local addr only", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.103/10"), NetfilterMode: NetfilterOff, }, want: ` up ip addr add 100.101.102.103/10 dev tailscale0` + basic, }, { name: "addr and routes", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.103/10"), Routes: mustCIDRs("100.100.100.100/32", "192.168.16.0/24"), NetfilterMode: NetfilterOff, }, want: ` up ip addr add 100.101.102.103/10 dev tailscale0 ip route add 100.100.100.100/32 dev tailscale0 table 52 ip route add 192.168.16.0/24 dev tailscale0 table 52` + basic, }, { name: "addr and routes and subnet routes", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.103/10"), Routes: mustCIDRs("100.100.100.100/32", "192.168.16.0/24"), SubnetRoutes: mustCIDRs("200.0.0.0/8"), NetfilterMode: NetfilterOff, }, want: ` up ip addr add 100.101.102.103/10 dev tailscale0 ip route add 100.100.100.100/32 dev tailscale0 table 52 ip route add 192.168.16.0/24 dev tailscale0 table 52` + basic, }, { name: "addr and routes and subnet routes with netfilter", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.104/10"), Routes: mustCIDRs("100.100.100.100/32", "10.0.0.0/8"), SubnetRoutes: mustCIDRs("200.0.0.0/8"), SNATSubnetRoutes: true, NetfilterMode: NetfilterOn, }, want: ` up ip addr add 100.101.102.104/10 dev tailscale0 ip route add 10.0.0.0/8 dev tailscale0 table 52 ip route add 100.100.100.100/32 dev tailscale0 table 52` + basic + `v4/filter/FORWARD -j ts-forward v4/filter/INPUT -j ts-input v4/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v4/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v4/filter/ts-forward -o tailscale0 -s 100.64.0.0/10 -j DROP v4/filter/ts-forward -o tailscale0 -j ACCEPT v4/filter/ts-input -i lo -s 100.101.102.104 -j ACCEPT v4/filter/ts-input ! -i tailscale0 -s 100.115.92.0/23 -j RETURN v4/filter/ts-input ! -i tailscale0 -s 100.64.0.0/10 -j DROP v4/nat/POSTROUTING -j ts-postrouting v4/nat/ts-postrouting -m mark --mark 0x40000 -j MASQUERADE v6/filter/FORWARD -j ts-forward v6/filter/INPUT -j ts-input v6/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v6/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v6/filter/ts-forward -o tailscale0 -j ACCEPT v6/nat/POSTROUTING -j ts-postrouting v6/nat/ts-postrouting -m mark --mark 0x40000 -j MASQUERADE `, }, { name: "addr and routes with netfilter", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.104/10"), Routes: mustCIDRs("100.100.100.100/32", "10.0.0.0/8"), NetfilterMode: NetfilterOn, }, want: ` up ip addr add 100.101.102.104/10 dev tailscale0 ip route add 10.0.0.0/8 dev tailscale0 table 52 ip route add 100.100.100.100/32 dev tailscale0 table 52` + basic + `v4/filter/FORWARD -j ts-forward v4/filter/INPUT -j ts-input v4/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v4/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v4/filter/ts-forward -o tailscale0 -s 100.64.0.0/10 -j DROP v4/filter/ts-forward -o tailscale0 -j ACCEPT v4/filter/ts-input -i lo -s 100.101.102.104 -j ACCEPT v4/filter/ts-input ! -i tailscale0 -s 100.115.92.0/23 -j RETURN v4/filter/ts-input ! -i tailscale0 -s 100.64.0.0/10 -j DROP v4/nat/POSTROUTING -j ts-postrouting v6/filter/FORWARD -j ts-forward v6/filter/INPUT -j ts-input v6/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v6/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v6/filter/ts-forward -o tailscale0 -j ACCEPT v6/nat/POSTROUTING -j ts-postrouting `, }, { name: "addr and routes and subnet routes with netfilter but no SNAT", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.104/10"), Routes: mustCIDRs("100.100.100.100/32", "10.0.0.0/8"), SubnetRoutes: mustCIDRs("200.0.0.0/8"), SNATSubnetRoutes: false, NetfilterMode: NetfilterOn, }, want: ` up ip addr add 100.101.102.104/10 dev tailscale0 ip route add 10.0.0.0/8 dev tailscale0 table 52 ip route add 100.100.100.100/32 dev tailscale0 table 52` + basic + `v4/filter/FORWARD -j ts-forward v4/filter/INPUT -j ts-input v4/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v4/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v4/filter/ts-forward -o tailscale0 -s 100.64.0.0/10 -j DROP v4/filter/ts-forward -o tailscale0 -j ACCEPT v4/filter/ts-input -i lo -s 100.101.102.104 -j ACCEPT v4/filter/ts-input ! -i tailscale0 -s 100.115.92.0/23 -j RETURN v4/filter/ts-input ! -i tailscale0 -s 100.64.0.0/10 -j DROP v4/nat/POSTROUTING -j ts-postrouting v6/filter/FORWARD -j ts-forward v6/filter/INPUT -j ts-input v6/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v6/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v6/filter/ts-forward -o tailscale0 -j ACCEPT v6/nat/POSTROUTING -j ts-postrouting `, }, { name: "addr and routes with netfilter", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.104/10"), Routes: mustCIDRs("100.100.100.100/32", "10.0.0.0/8"), NetfilterMode: NetfilterOn, }, want: ` up ip addr add 100.101.102.104/10 dev tailscale0 ip route add 10.0.0.0/8 dev tailscale0 table 52 ip route add 100.100.100.100/32 dev tailscale0 table 52` + basic + `v4/filter/FORWARD -j ts-forward v4/filter/INPUT -j ts-input v4/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v4/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v4/filter/ts-forward -o tailscale0 -s 100.64.0.0/10 -j DROP v4/filter/ts-forward -o tailscale0 -j ACCEPT v4/filter/ts-input -i lo -s 100.101.102.104 -j ACCEPT v4/filter/ts-input ! -i tailscale0 -s 100.115.92.0/23 -j RETURN v4/filter/ts-input ! -i tailscale0 -s 100.64.0.0/10 -j DROP v4/nat/POSTROUTING -j ts-postrouting v6/filter/FORWARD -j ts-forward v6/filter/INPUT -j ts-input v6/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v6/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v6/filter/ts-forward -o tailscale0 -j ACCEPT v6/nat/POSTROUTING -j ts-postrouting `, }, { name: "addr and routes with half netfilter", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.104/10"), Routes: mustCIDRs("100.100.100.100/32", "10.0.0.0/8"), NetfilterMode: NetfilterNoDivert, }, want: ` up ip addr add 100.101.102.104/10 dev tailscale0 ip route add 10.0.0.0/8 dev tailscale0 table 52 ip route add 100.100.100.100/32 dev tailscale0 table 52` + basic + `v4/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v4/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v4/filter/ts-forward -o tailscale0 -s 100.64.0.0/10 -j DROP v4/filter/ts-forward -o tailscale0 -j ACCEPT v4/filter/ts-input -i lo -s 100.101.102.104 -j ACCEPT v4/filter/ts-input ! -i tailscale0 -s 100.115.92.0/23 -j RETURN v4/filter/ts-input ! -i tailscale0 -s 100.64.0.0/10 -j DROP v6/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v6/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v6/filter/ts-forward -o tailscale0 -j ACCEPT `, }, { name: "addr and routes with netfilter2", in: &Config{ LocalAddrs: mustCIDRs("100.101.102.104/10"), Routes: mustCIDRs("100.100.100.100/32", "10.0.0.0/8"), NetfilterMode: NetfilterOn, }, want: ` up ip addr add 100.101.102.104/10 dev tailscale0 ip route add 10.0.0.0/8 dev tailscale0 table 52 ip route add 100.100.100.100/32 dev tailscale0 table 52` + basic + `v4/filter/FORWARD -j ts-forward v4/filter/INPUT -j ts-input v4/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v4/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v4/filter/ts-forward -o tailscale0 -s 100.64.0.0/10 -j DROP v4/filter/ts-forward -o tailscale0 -j ACCEPT v4/filter/ts-input -i lo -s 100.101.102.104 -j ACCEPT v4/filter/ts-input ! -i tailscale0 -s 100.115.92.0/23 -j RETURN v4/filter/ts-input ! -i tailscale0 -s 100.64.0.0/10 -j DROP v4/nat/POSTROUTING -j ts-postrouting v6/filter/FORWARD -j ts-forward v6/filter/INPUT -j ts-input v6/filter/ts-forward -i tailscale0 -j MARK --set-mark 0x40000 v6/filter/ts-forward -m mark --mark 0x40000 -j ACCEPT v6/filter/ts-forward -o tailscale0 -j ACCEPT v6/nat/POSTROUTING -j ts-postrouting `, }, } fake := NewFakeOS(t) router, err := newUserspaceRouterAdvanced(t.Logf, "tailscale0", fake.netfilter4, fake.netfilter6, fake) if err != nil { t.Fatalf("failed to create router: %v", err) } if err := router.Up(); err != nil { t.Fatalf("failed to up router: %v", err) } testState := func(t *testing.T, i int) { t.Helper() if err := router.Set(states[i].in); err != nil { t.Fatalf("failed to set router config: %v", err) } got := fake.String() want := strings.TrimSpace(states[i].want) if diff := cmp.Diff(got, want); diff != "" { t.Fatalf("unexpected OS state (-got+want):\n%s", diff) } } for i, state := range states { t.Run(state.name, func(t *testing.T) { testState(t, i) }) } // Cycle through a bunch of states in pseudorandom order, to // verify that we transition cleanly from state to state no matter // the order. for randRun := 0; randRun < 5*len(states); randRun++ { i := rand.Intn(len(states)) state := states[i] t.Run(state.name, func(t *testing.T) { testState(t, i) }) } } type fakeNetfilter struct { t *testing.T n map[string][]string } func newNetfilter(t *testing.T) *fakeNetfilter { return &fakeNetfilter{ t: t, n: map[string][]string{ "filter/INPUT": nil, "filter/OUTPUT": nil, "filter/FORWARD": nil, "nat/PREROUTING": nil, "nat/OUTPUT": nil, "nat/POSTROUTING": nil, }, } } func (n *fakeNetfilter) Insert(table, chain string, pos int, args ...string) error { k := table + "/" + chain if rules, ok := n.n[k]; ok { if pos > len(rules)+1 { n.t.Errorf("bad position %d in %s", pos, k) return errExec } rules = append(rules, "") copy(rules[pos:], rules[pos-1:]) rules[pos-1] = strings.Join(args, " ") n.n[k] = rules } else { n.t.Errorf("unknown table/chain %s", k) return errExec } return nil } func (n *fakeNetfilter) Append(table, chain string, args ...string) error { k := table + "/" + chain return n.Insert(table, chain, len(n.n[k])+1, args...) } func (n *fakeNetfilter) Exists(table, chain string, args ...string) (bool, error) { k := table + "/" + chain if rules, ok := n.n[k]; ok { for _, rule := range rules { if rule == strings.Join(args, " ") { return true, nil } } return false, nil } else { n.t.Errorf("unknown table/chain %s", k) return false, errExec } } func (n *fakeNetfilter) Delete(table, chain string, args ...string) error { k := table + "/" + chain if rules, ok := n.n[k]; ok { for i, rule := range rules { if rule == strings.Join(args, " ") { rules = append(rules[:i], rules[i+1:]...) n.n[k] = rules return nil } } n.t.Errorf("delete of unknown rule %q from %s", strings.Join(args, " "), k) return errExec } else { n.t.Errorf("unknown table/chain %s", k) return errExec } } func (n *fakeNetfilter) ClearChain(table, chain string) error { k := table + "/" + chain if _, ok := n.n[k]; ok { n.n[k] = nil return nil } else { n.t.Logf("note: ClearChain: unknown table/chain %s", k) return errors.New("exitcode:1") } } func (n *fakeNetfilter) NewChain(table, chain string) error { k := table + "/" + chain if _, ok := n.n[k]; ok { n.t.Errorf("table/chain %s already exists", k) return errExec } n.n[k] = nil return nil } func (n *fakeNetfilter) DeleteChain(table, chain string) error { k := table + "/" + chain if rules, ok := n.n[k]; ok { if len(rules) != 0 { n.t.Errorf("%s is not empty", k) return errExec } delete(n.n, k) return nil } else { n.t.Errorf("%s does not exist", k) return errExec } } // fakeOS implements commandRunner and provides v4 and v6 // netfilterRunners, but captures changes without touching the OS. type fakeOS struct { t *testing.T up bool ips []string routes []string rules []string netfilter4 *fakeNetfilter netfilter6 *fakeNetfilter } func NewFakeOS(t *testing.T) *fakeOS { return &fakeOS{ t: t, netfilter4: newNetfilter(t), netfilter6: newNetfilter(t), } } var errExec = errors.New("execution failed") func (o *fakeOS) String() string { var b strings.Builder if o.up { b.WriteString("up\n") } else { b.WriteString("down\n") } for _, ip := range o.ips { fmt.Fprintf(&b, "ip addr add %s\n", ip) } for _, route := range o.routes { fmt.Fprintf(&b, "ip route add %s\n", route) } for _, rule := range o.rules { fmt.Fprintf(&b, "ip rule add %s\n", rule) } var chains []string for chain := range o.netfilter4.n { chains = append(chains, chain) } sort.Strings(chains) for _, chain := range chains { for _, rule := range o.netfilter4.n[chain] { fmt.Fprintf(&b, "v4/%s %s\n", chain, rule) } } chains = nil for chain := range o.netfilter6.n { chains = append(chains, chain) } sort.Strings(chains) for _, chain := range chains { for _, rule := range o.netfilter6.n[chain] { fmt.Fprintf(&b, "v6/%s %s\n", chain, rule) } } return b.String()[:len(b.String())-1] } func (o *fakeOS) run(args ...string) error { unexpected := func() error { o.t.Errorf("unexpected invocation %q", strings.Join(args, " ")) return errors.New("unrecognized invocation") } if args[0] != "ip" { return unexpected() } if len(args) == 2 && args[1] == "rule" { // naked invocation of `ip rule` is a feature test. Return // successfully. return nil } family := "" rest := strings.Join(args[3:], " ") if args[1] == "-4" || args[1] == "-6" { family = args[1] copy(args[1:], args[2:]) args = args[:len(args)-1] rest = family + " " + strings.Join(args[3:], " ") } var l *[]string switch args[1] { case "link": got := strings.Join(args[2:], " ") switch got { case "set dev tailscale0 up": o.up = true case "set dev tailscale0 down": o.up = false default: return unexpected() } return nil case "addr": l = &o.ips case "route": l = &o.routes case "rule": l = &o.rules default: return unexpected() } switch args[2] { case "add": for _, el := range *l { if el == rest { o.t.Errorf("can't add %q, already present", rest) return errors.New("already exists") } } *l = append(*l, rest) sort.Strings(*l) case "del": found := false for i, el := range *l { if el == rest { found = true *l = append((*l)[:i], (*l)[i+1:]...) break } } if !found { o.t.Logf("note: can't delete %q, not present", rest) // 'ip rule del' exits with code 2 when a row is // missing. We don't want to consider that an error, // for cleanup purposes. // TODO(apenwarr): this is a hack. // I'd like to return an exec.ExitError(2) here, but // I can't, because the ExitCode is implemented in // os.ProcessState, which is an opaque object I can't // instantiate or modify. Go's 75 levels of abstraction // between me and an 8-bit int are really paying off // here, as you can see. return errors.New("exitcode:2") } default: return unexpected() } return nil } func (o *fakeOS) output(args ...string) ([]byte, error) { want := "ip rule list priority 10000" got := strings.Join(args, " ") if got != want { o.t.Errorf("unexpected command that wants output: %v", got) return nil, errExec } var ret []string for _, rule := range o.rules { if strings.Contains(rule, "10000") { ret = append(ret, rule) } } return []byte(strings.Join(ret, "\n")), nil }