82 lines
2.2 KiB
Go
82 lines
2.2 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: MPL-2.0
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package fingerprint
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import (
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"fmt"
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"os"
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"os/exec"
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"regexp"
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"strconv"
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"strings"
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)
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// linkSpeedSys parses link speed in Mb/s from /sys.
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func (f *NetworkFingerprint) linkSpeedSys(device string) int {
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path := fmt.Sprintf("/sys/class/net/%s/speed", device)
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// Read contents of the device/speed file
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content, err := os.ReadFile(path)
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if err != nil {
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f.logger.Debug("unable to read link speed", "path", path, "device", device)
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return 0
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}
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lines := strings.Split(string(content), "\n")
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mbs, err := strconv.Atoi(lines[0])
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if err != nil || mbs <= 0 {
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f.logger.Debug("unable to parse link speed", "path", path, "device", device)
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return 0
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}
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return mbs
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}
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// linkSpeed returns link speed in Mb/s, or 0 when unable to determine it.
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func (f *NetworkFingerprint) linkSpeed(device string) int {
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// Use LookPath to find the ethtool in the systems $PATH
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// If it's not found or otherwise errors, LookPath returns and empty string
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// and an error we can ignore for our purposes
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ethtoolPath, _ := exec.LookPath("ethtool")
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if ethtoolPath != "" {
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if speed := f.linkSpeedEthtool(ethtoolPath, device); speed > 0 {
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return speed
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}
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}
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// Fall back on checking a system file for link speed.
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return f.linkSpeedSys(device)
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}
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// linkSpeedEthtool determines link speed in Mb/s with 'ethtool'.
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func (f *NetworkFingerprint) linkSpeedEthtool(path, device string) int {
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outBytes, err := exec.Command(path, device).Output()
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if err != nil {
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f.logger.Warn("error calling ethtool", "error", err, "path", path, "device", device)
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return 0
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}
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output := strings.TrimSpace(string(outBytes))
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re := regexp.MustCompile("Speed: [0-9]+[a-zA-Z]+/s")
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m := re.FindString(output)
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if m == "" {
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// no matches found, output may be in a different format
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f.logger.Warn("unable to parse speed", "path", path, "device", device)
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return 0
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}
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// Split and trim the Mb/s unit from the string output
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args := strings.Split(m, ": ")
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raw := strings.TrimSuffix(args[1], "Mb/s")
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// convert to Mb/s
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mbs, err := strconv.Atoi(raw)
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if err != nil || mbs <= 0 {
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f.logger.Warn("unable to parse Mb/s", "path", path, "device", device)
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return 0
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}
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return mbs
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}
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