Move Linux client & common packages into a public repo.

portlist/portlist.go

@@ -0,0 +1,87 @@
+// 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 portlist
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Port struct {
+	Proto   string
+	Port    uint16
+	inode   string
+	Process string
+}
+
+type List []Port
+
+var protos = []string{"tcp", "udp"}
+
+func (a *Port) lessThan(b *Port) bool {
+	if a.Port < b.Port {
+		return true
+	} else if a.Port > b.Port {
+		return false
+	}
+
+	if a.Proto < b.Proto {
+		return true
+	} else if a.Proto > b.Proto {
+		return false
+	}
+
+	if a.inode < b.inode {
+		return true
+	} else if a.inode > b.inode {
+		return false
+	}
+
+	if a.Process < b.Process {
+		return true
+	} else if a.Process > b.Process {
+		return false
+	}
+	return false
+}
+
+func (a List) SameInodes(b List) bool {
+	if a == nil || b == nil || len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i].Proto != b[i].Proto ||
+			a[i].Port != b[i].Port ||
+			a[i].inode != b[i].inode {
+			return false
+		}
+	}
+	return true
+}
+
+func (pl List) String() string {
+	out := []string{}
+	for _, v := range pl {
+		out = append(out, fmt.Sprintf("%-3s %5d %-17s %#v",
+			v.Proto, v.Port, v.inode, v.Process))
+	}
+	return strings.Join(out, "\n")
+}
+
+func GetList(prev List) (List, error) {
+	pl, err := listPorts()
+	if err != nil {
+		return nil, fmt.Errorf("listPorts: %s", err)
+	}
+	if pl.SameInodes(prev) {
+		// Nothing changed, skip inode lookup
+		return prev, nil
+	}
+	pl, err = addProcesses(pl)
+	if err != nil {
+		return nil, fmt.Errorf("addProcesses: %s", err)
+	}
+	return pl, nil
+}