net_conntrackstat.go

Documentation: github.com/prometheus/procfs

     1  // Copyright 2020 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  
    14  package procfs
    15  
    16  import (
    17  	"bufio"
    18  	"bytes"
    19  	"fmt"
    20  	"io"
    21  	"strings"
    22  
    23  	"github.com/prometheus/procfs/internal/util"
    24  )
    25  
    26  // A ConntrackStatEntry represents one line from net/stat/nf_conntrack
    27  // and contains netfilter conntrack statistics at one CPU core.
    28  type ConntrackStatEntry struct {
    29  	Entries       uint64
    30  	Searched      uint64
    31  	Found         uint64
    32  	New           uint64
    33  	Invalid       uint64
    34  	Ignore        uint64
    35  	Delete        uint64
    36  	DeleteList    uint64
    37  	Insert        uint64
    38  	InsertFailed  uint64
    39  	Drop          uint64
    40  	EarlyDrop     uint64
    41  	SearchRestart uint64
    42  }
    43  
    44  // ConntrackStat retrieves netfilter's conntrack statistics, split by CPU cores.
    45  func (fs FS) ConntrackStat() ([]ConntrackStatEntry, error) {
    46  	return readConntrackStat(fs.proc.Path("net", "stat", "nf_conntrack"))
    47  }
    48  
    49  // Parses a slice of ConntrackStatEntries from the given filepath.
    50  func readConntrackStat(path string) ([]ConntrackStatEntry, error) {
    51  	// This file is small and can be read with one syscall.
    52  	b, err := util.ReadFileNoStat(path)
    53  	if err != nil {
    54  		// Do not wrap this error so the caller can detect os.IsNotExist and
    55  		// similar conditions.
    56  		return nil, err
    57  	}
    58  
    59  	stat, err := parseConntrackStat(bytes.NewReader(b))
    60  	if err != nil {
    61  		return nil, fmt.Errorf("%s: Cannot read file: %v: %w", ErrFileRead, path, err)
    62  	}
    63  
    64  	return stat, nil
    65  }
    66  
    67  // Reads the contents of a conntrack statistics file and parses a slice of ConntrackStatEntries.
    68  func parseConntrackStat(r io.Reader) ([]ConntrackStatEntry, error) {
    69  	var entries []ConntrackStatEntry
    70  
    71  	scanner := bufio.NewScanner(r)
    72  	scanner.Scan()
    73  	for scanner.Scan() {
    74  		fields := strings.Fields(scanner.Text())
    75  		conntrackEntry, err := parseConntrackStatEntry(fields)
    76  		if err != nil {
    77  			return nil, err
    78  		}
    79  		entries = append(entries, *conntrackEntry)
    80  	}
    81  
    82  	return entries, nil
    83  }
    84  
    85  // Parses a ConntrackStatEntry from given array of fields.
    86  func parseConntrackStatEntry(fields []string) (*ConntrackStatEntry, error) {
    87  	entries, err := util.ParseHexUint64s(fields)
    88  	if err != nil {
    89  		return nil, fmt.Errorf("%s: Cannot parse entry: %d: %w", ErrFileParse, entries, err)
    90  	}
    91  	numEntries := len(entries)
    92  	if numEntries < 16 || numEntries > 17 {
    93  		return nil,
    94  			fmt.Errorf("%w: invalid conntrackstat entry, invalid number of fields: %d", ErrFileParse, numEntries)
    95  	}
    96  
    97  	stats := &ConntrackStatEntry{
    98  		Entries:      *entries[0],
    99  		Searched:     *entries[1],
   100  		Found:        *entries[2],
   101  		New:          *entries[3],
   102  		Invalid:      *entries[4],
   103  		Ignore:       *entries[5],
   104  		Delete:       *entries[6],
   105  		DeleteList:   *entries[7],
   106  		Insert:       *entries[8],
   107  		InsertFailed: *entries[9],
   108  		Drop:         *entries[10],
   109  		EarlyDrop:    *entries[11],
   110  	}
   111  
   112  	// Ignore missing search_restart on Linux < 2.6.35.
   113  	if numEntries == 17 {
   114  		stats.SearchRestart = *entries[16]
   115  	}
   116  
   117  	return stats, nil
   118  }
   119
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