43 lines
812 B
Go
43 lines
812 B
Go
//go:build linux
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// +build linux
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package freeport
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import (
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"fmt"
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"os/exec"
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"regexp"
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"strconv"
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)
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/*
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$ sysctl -n net.ipv4.ip_local_port_range
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32768 60999
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*/
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const ephemeralPortRangeSysctlKey = "net.ipv4.ip_local_port_range"
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var ephemeralPortRangePatt = regexp.MustCompile(`^\s*(\d+)\s+(\d+)\s*$`)
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func getEphemeralPortRange() (int, int, error) {
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cmd := exec.Command("sysctl", "-n", ephemeralPortRangeSysctlKey)
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out, err := cmd.Output()
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if err != nil {
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return 0, 0, err
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}
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val := string(out)
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m := ephemeralPortRangePatt.FindStringSubmatch(val)
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if m != nil {
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min, err1 := strconv.Atoi(m[1])
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max, err2 := strconv.Atoi(m[2])
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if err1 == nil && err2 == nil {
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return min, max, nil
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}
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}
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return 0, 0, fmt.Errorf("unexpected sysctl value %q for key %q", val, ephemeralPortRangeSysctlKey)
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}
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