1// Copyright 2019 The Prometheus Authors
2// Licensed under the Apache License, Version 2.0 (the "License");
3// you may not use this file except in compliance with the License.
4// You may obtain a copy of the License at
5//
6// http://www.apache.org/licenses/LICENSE-2.0
7//
8// Unless required by applicable law or agreed to in writing, software
9// distributed under the License is distributed on an "AS IS" BASIS,
10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11// See the License for the specific language governing permissions and
12// limitations under the License.
13
14package procfs
15
16import (
17	"bufio"
18	"bytes"
19	"fmt"
20	"io"
21	"strconv"
22	"strings"
23
24	"github.com/prometheus/procfs/internal/util"
25)
26
27// For the proc file format details,
28// See:
29// * Linux 2.6.23 https://elixir.bootlin.com/linux/v2.6.23/source/net/core/dev.c#L2343
30// * Linux 4.17 https://elixir.bootlin.com/linux/v4.17/source/net/core/net-procfs.c#L162
31// and https://elixir.bootlin.com/linux/v4.17/source/include/linux/netdevice.h#L2810.
32
33// SoftnetStat contains a single row of data from /proc/net/softnet_stat
34type SoftnetStat struct {
35	// Number of processed packets
36	Processed uint32
37	// Number of dropped packets
38	Dropped uint32
39	// Number of times processing packets ran out of quota
40	TimeSqueezed uint32
41}
42
43var softNetProcFile = "net/softnet_stat"
44
45// NetSoftnetStat reads data from /proc/net/softnet_stat.
46func (fs FS) NetSoftnetStat() ([]SoftnetStat, error) {
47	b, err := util.ReadFileNoStat(fs.proc.Path(softNetProcFile))
48	if err != nil {
49		return nil, err
50	}
51
52	entries, err := parseSoftnet(bytes.NewReader(b))
53	if err != nil {
54		return nil, fmt.Errorf("failed to parse /proc/net/softnet_stat: %w", err)
55	}
56
57	return entries, nil
58}
59
60func parseSoftnet(r io.Reader) ([]SoftnetStat, error) {
61	const minColumns = 9
62
63	s := bufio.NewScanner(r)
64
65	var stats []SoftnetStat
66	for s.Scan() {
67		columns := strings.Fields(s.Text())
68		width := len(columns)
69
70		if width < minColumns {
71			return nil, fmt.Errorf("%d columns were detected, but at least %d were expected", width, minColumns)
72		}
73
74		// We only parse the first three columns at the moment.
75		us, err := parseHexUint32s(columns[0:3])
76		if err != nil {
77			return nil, err
78		}
79
80		stats = append(stats, SoftnetStat{
81			Processed:    us[0],
82			Dropped:      us[1],
83			TimeSqueezed: us[2],
84		})
85	}
86
87	return stats, nil
88}
89
90func parseHexUint32s(ss []string) ([]uint32, error) {
91	us := make([]uint32, 0, len(ss))
92	for _, s := range ss {
93		u, err := strconv.ParseUint(s, 16, 32)
94		if err != nil {
95			return nil, err
96		}
97
98		us = append(us, uint32(u))
99	}
100
101	return us, nil
102}
103