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tailscale/wgengine/filter/match.go

118 lines
2.2 KiB
Go

// 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 filter
import (
"fmt"
"strings"
"inet.af/netaddr"
"tailscale.com/net/packet"
)
// PortRange is a range of TCP and UDP ports.
type PortRange struct {
First, Last uint16 // inclusive
}
func (pr PortRange) String() string {
if pr.First == 0 && pr.Last == 65535 {
return "*"
} else if pr.First == pr.Last {
return fmt.Sprintf("%d", pr.First)
} else {
return fmt.Sprintf("%d-%d", pr.First, pr.Last)
}
}
// contains returns whether port is in pr.
func (pr PortRange) contains(port uint16) bool {
return port >= pr.First && port <= pr.Last
}
// NetPortRange combines an IP address prefix and PortRange.
type NetPortRange struct {
Net netaddr.IPPrefix
Ports PortRange
}
func (npr NetPortRange) String() string {
return fmt.Sprintf("%v:%v", npr.Net, npr.Ports)
}
// Match matches packets from any IP address in Srcs to any ip:port in
// Dsts.
type Match struct {
Dsts []NetPortRange
Srcs []netaddr.IPPrefix
}
func (m Match) String() string {
srcs := []string{}
for _, src := range m.Srcs {
srcs = append(srcs, src.String())
}
dsts := []string{}
for _, dst := range m.Dsts {
dsts = append(dsts, dst.String())
}
var ss, ds string
if len(srcs) == 1 {
ss = srcs[0]
} else {
ss = "[" + strings.Join(srcs, ",") + "]"
}
if len(dsts) == 1 {
ds = dsts[0]
} else {
ds = "[" + strings.Join(dsts, ",") + "]"
}
return fmt.Sprintf("%v=>%v", ss, ds)
}
type matches []Match
func (ms matches) match(q *packet.Parsed) bool {
for _, m := range ms {
if !ipInList(q.Src.IP, m.Srcs) {
continue
}
for _, dst := range m.Dsts {
if !dst.Net.Contains(q.Dst.IP) {
continue
}
if !dst.Ports.contains(q.Dst.Port) {
continue
}
return true
}
}
return false
}
func (ms matches) matchIPsOnly(q *packet.Parsed) bool {
for _, m := range ms {
if !ipInList(q.Src.IP, m.Srcs) {
continue
}
for _, dst := range m.Dsts {
if dst.Net.Contains(q.Dst.IP) {
return true
}
}
}
return false
}
func ipInList(ip netaddr.IP, netlist []netaddr.IPPrefix) bool {
for _, net := range netlist {
if net.Contains(ip) {
return true
}
}
return false
}