Source: net_softnet.go in package github.com/prometheus/procfs

Copyright 2019 The Prometheus Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.


package procfs

import (
	"fmt"
	"io/ioutil"
	"strconv"
	"strings"
)

For the proc file format details, see https://elixir.bootlin.com/linux/v4.17/source/net/core/net-procfs.c#L162 and https://elixir.bootlin.com/linux/v4.17/source/include/linux/netdevice.h#L2810.

SoftnetEntry contains a single row of data from /proc/net/softnet_stat

Number of processed packets

Number of dropped packets

Number of times processing packets ran out of quota

	TimeSqueezed uint
}

GatherSoftnetStats reads /proc/net/softnet_stat, parse the relevant columns, and then return a slice of SoftnetEntry's.

func (fs FS) GatherSoftnetStats() ([]SoftnetEntry, error) {
	data, err := ioutil.ReadFile(fs.proc.Path("net/softnet_stat"))
	if err != nil {
		return nil, fmt.Errorf("error reading softnet %s: %s", fs.proc.Path("net/softnet_stat"), err)
	}

	return parseSoftnetEntries(data)
}

func parseSoftnetEntries(data []byte) ([]SoftnetEntry, error) {
	lines := strings.Split(string(data), "\n")
	entries := make([]SoftnetEntry, 0)
	var err error
	const (
		expectedColumns = 11
	)
	for _, line := range lines {
		columns := strings.Fields(line)
		width := len(columns)
		if width == 0 {
			continue
		}
		if width != expectedColumns {
			return []SoftnetEntry{}, fmt.Errorf("%d columns were detected, but %d were expected", width, expectedColumns)
		}
		var entry SoftnetEntry
		if entry, err = parseSoftnetEntry(columns); err != nil {
			return []SoftnetEntry{}, err
		}
		entries = append(entries, entry)
	}

	return entries, nil
}

func parseSoftnetEntry(columns []string) (SoftnetEntry, error) {
	var err error
	var processed, dropped, timeSqueezed uint64
	if processed, err = strconv.ParseUint(columns[0], 16, 32); err != nil {
		return SoftnetEntry{}, fmt.Errorf("Unable to parse column 0: %s", err)
	}
	if dropped, err = strconv.ParseUint(columns[1], 16, 32); err != nil {
		return SoftnetEntry{}, fmt.Errorf("Unable to parse column 1: %s", err)
	}
	if timeSqueezed, err = strconv.ParseUint(columns[2], 16, 32); err != nil {
		return SoftnetEntry{}, fmt.Errorf("Unable to parse column 2: %s", err)
	}
	return SoftnetEntry{
		Processed:    uint(processed),
		Dropped:      uint(dropped),
		TimeSqueezed: uint(timeSqueezed),
	}, nil