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// Copyright 2020 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 (
"bufio"
"encoding/hex"
"fmt"
"io"
"net"
"os"
"strconv"
"strings"
)
const (
// readLimit is used by io.LimitReader while reading the content of the
// /proc/net/udp{,6} files. The number of lines inside such a file is dynamic
// as each line represents a single used socket.
// In theory, the number of available sockets is 65535 (2^16 - 1) per IP.
// With e.g. 150 Byte per line and the maximum number of 65535,
// the reader needs to handle 150 Byte * 65535 =~ 10 MB for a single IP.
readLimit = 4294967296 // Byte -> 4 GiB
)
type (
// NetUDP represents the contents of /proc/net/udp{,6} file without the header.
NetUDP []*netUDPLine
// NetUDPSummary provides already computed values like the total queue lengths or
// the total number of used sockets. In contrast to NetUDP it does not collect
// the parsed lines into a slice.
NetUDPSummary struct {
// TxQueueLength shows the total queue length of all parsed tx_queue lengths.
TxQueueLength uint64
// RxQueueLength shows the total queue length of all parsed rx_queue lengths.
RxQueueLength uint64
// UsedSockets shows the total number of parsed lines representing the
// number of used sockets.
UsedSockets uint64
}
// netUDPLine represents the fields parsed from a single line
// in /proc/net/udp{,6}. Fields which are not used by UDP are skipped.
// For the proc file format details, see https://linux.die.net/man/5/proc.
netUDPLine struct {
Sl uint64
LocalAddr net.IP
LocalPort uint64
RemAddr net.IP
RemPort uint64
St uint64
TxQueue uint64
RxQueue uint64
UID uint64
}
)
// NetUDP returns the IPv4 kernel/networking statistics for UDP datagrams
// read from /proc/net/udp.
func (fs FS) NetUDP() (NetUDP, error) {
return newNetUDP(fs.proc.Path("net/udp"))
}
// NetUDP6 returns the IPv6 kernel/networking statistics for UDP datagrams
// read from /proc/net/udp6.
func (fs FS) NetUDP6() (NetUDP, error) {
return newNetUDP(fs.proc.Path("net/udp6"))
}
// NetUDPSummary returns already computed statistics like the total queue lengths
// for UDP datagrams read from /proc/net/udp.
func (fs FS) NetUDPSummary() (*NetUDPSummary, error) {
return newNetUDPSummary(fs.proc.Path("net/udp"))
}
// NetUDP6Summary returns already computed statistics like the total queue lengths
// for UDP datagrams read from /proc/net/udp6.
func (fs FS) NetUDP6Summary() (*NetUDPSummary, error) {
return newNetUDPSummary(fs.proc.Path("net/udp6"))
}
// newNetUDP creates a new NetUDP{,6} from the contents of the given file.
func newNetUDP(file string) (NetUDP, error) {
f, err := os.Open(file)
if err != nil {
return nil, err
}
defer f.Close()
netUDP := NetUDP{}
lr := io.LimitReader(f, readLimit)
s := bufio.NewScanner(lr)
s.Scan() // skip first line with headers
for s.Scan() {
fields := strings.Fields(s.Text())
line, err := parseNetUDPLine(fields)
if err != nil {
return nil, err
}
netUDP = append(netUDP, line)
}
if err := s.Err(); err != nil {
return nil, err
}
return netUDP, nil
}
// newNetUDPSummary creates a new NetUDP{,6} from the contents of the given file.
func newNetUDPSummary(file string) (*NetUDPSummary, error) {
f, err := os.Open(file)
if err != nil {
return nil, err
}
defer f.Close()
netUDPSummary := &NetUDPSummary{}
lr := io.LimitReader(f, readLimit)
s := bufio.NewScanner(lr)
s.Scan() // skip first line with headers
for s.Scan() {
fields := strings.Fields(s.Text())
line, err := parseNetUDPLine(fields)
if err != nil {
return nil, err
}
netUDPSummary.TxQueueLength += line.TxQueue
netUDPSummary.RxQueueLength += line.RxQueue
netUDPSummary.UsedSockets++
}
if err := s.Err(); err != nil {
return nil, err
}
return netUDPSummary, nil
}
// parseNetUDPLine parses a single line, represented by a list of fields.
func parseNetUDPLine(fields []string) (*netUDPLine, error) {
line := &netUDPLine{}
if len(fields) < 8 {
return nil, fmt.Errorf(
"cannot parse net udp socket line as it has less then 8 columns: %s",
strings.Join(fields, " "),
)
}
var err error // parse error
// sl
s := strings.Split(fields[0], ":")
if len(s) != 2 {
return nil, fmt.Errorf(
"cannot parse sl field in udp socket line: %s", fields[0])
}
if line.Sl, err = strconv.ParseUint(s[0], 0, 64); err != nil {
return nil, fmt.Errorf("cannot parse sl value in udp socket line: %s", err)
}
// local_address
l := strings.Split(fields[1], ":")
if len(l) != 2 {
return nil, fmt.Errorf(
"cannot parse local_address field in udp socket line: %s", fields[1])
}
if line.LocalAddr, err = hex.DecodeString(l[0]); err != nil {
return nil, fmt.Errorf(
"cannot parse local_address value in udp socket line: %s", err)
}
if line.LocalPort, err = strconv.ParseUint(l[1], 16, 64); err != nil {
return nil, fmt.Errorf(
"cannot parse local_address port value in udp socket line: %s", err)
}
// remote_address
r := strings.Split(fields[2], ":")
if len(r) != 2 {
return nil, fmt.Errorf(
"cannot parse rem_address field in udp socket line: %s", fields[1])
}
if line.RemAddr, err = hex.DecodeString(r[0]); err != nil {
return nil, fmt.Errorf(
"cannot parse rem_address value in udp socket line: %s", err)
}
if line.RemPort, err = strconv.ParseUint(r[1], 16, 64); err != nil {
return nil, fmt.Errorf(
"cannot parse rem_address port value in udp socket line: %s", err)
}
// st
if line.St, err = strconv.ParseUint(fields[3], 16, 64); err != nil {
return nil, fmt.Errorf(
"cannot parse st value in udp socket line: %s", err)
}
// tx_queue and rx_queue
q := strings.Split(fields[4], ":")
if len(q) != 2 {
return nil, fmt.Errorf(
"cannot parse tx/rx queues in udp socket line as it has a missing colon: %s",
fields[4],
)
}
if line.TxQueue, err = strconv.ParseUint(q[0], 16, 64); err != nil {
return nil, fmt.Errorf("cannot parse tx_queue value in udp socket line: %s", err)
}
if line.RxQueue, err = strconv.ParseUint(q[1], 16, 64); err != nil {
return nil, fmt.Errorf("cannot parse rx_queue value in udp socket line: %s", err)
}
// uid
if line.UID, err = strconv.ParseUint(fields[7], 0, 64); err != nil {
return nil, fmt.Errorf(
"cannot parse uid value in udp socket line: %s", err)
}
return line, nil
}
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