syncthing/vendor/github.com/prometheus/procfs/ipvs.go
Jakob Borg 916ec63af6 cmd/stdiscosrv: New discovery server (fixes #4618)
This is a new revision of the discovery server. Relevant changes and
non-changes:

- Protocol towards clients is unchanged.

- Recommended large scale design is still to be deployed nehind nginx (I
  tested, and it's still a lot faster at terminating TLS).

- Database backend is leveldb again, only. It scales enough, is easy to
  setup, and we don't need any backend to take care of.

- Server supports replication. This is a simple TCP channel - protect it
  with a firewall when deploying over the internet. (We deploy this within
  the same datacenter, and with firewall.) Any incoming client announces
  are sent over the replication channel(s) to other peer discosrvs.
  Incoming replication changes are applied to the database as if they came
  from clients, but without the TLS/certificate overhead.

- Metrics are exposed using the prometheus library, when enabled.

- The database values and replication protocol is protobuf, because JSON
  was quite CPU intensive when I tried that and benchmarked it.

- The "Retry-After" value for failed lookups gets slowly increased from
  a default of 120 seconds, by 5 seconds for each failed lookup,
  independently by each discosrv. This lowers the query load over time for
  clients that are never seen. The Retry-After maxes out at 3600 after a
  couple of weeks of this increase. The number of failed lookups is
  stored in the database, now and then (avoiding making each lookup a
  database put).

All in all this means clients can be pointed towards a cluster using
just multiple A / AAAA records to gain both load sharing and redundancy
(if one is down, clients will talk to the remaining ones).

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4648
2018-01-14 08:52:31 +00:00

247 lines
5.7 KiB
Go

package procfs
import (
"bufio"
"encoding/hex"
"errors"
"fmt"
"io"
"io/ioutil"
"net"
"os"
"strconv"
"strings"
)
// IPVSStats holds IPVS statistics, as exposed by the kernel in `/proc/net/ip_vs_stats`.
type IPVSStats struct {
// Total count of connections.
Connections uint64
// Total incoming packages processed.
IncomingPackets uint64
// Total outgoing packages processed.
OutgoingPackets uint64
// Total incoming traffic.
IncomingBytes uint64
// Total outgoing traffic.
OutgoingBytes uint64
}
// IPVSBackendStatus holds current metrics of one virtual / real address pair.
type IPVSBackendStatus struct {
// The local (virtual) IP address.
LocalAddress net.IP
// The remote (real) IP address.
RemoteAddress net.IP
// The local (virtual) port.
LocalPort uint16
// The remote (real) port.
RemotePort uint16
// The local firewall mark
LocalMark string
// The transport protocol (TCP, UDP).
Proto string
// The current number of active connections for this virtual/real address pair.
ActiveConn uint64
// The current number of inactive connections for this virtual/real address pair.
InactConn uint64
// The current weight of this virtual/real address pair.
Weight uint64
}
// NewIPVSStats reads the IPVS statistics.
func NewIPVSStats() (IPVSStats, error) {
fs, err := NewFS(DefaultMountPoint)
if err != nil {
return IPVSStats{}, err
}
return fs.NewIPVSStats()
}
// NewIPVSStats reads the IPVS statistics from the specified `proc` filesystem.
func (fs FS) NewIPVSStats() (IPVSStats, error) {
file, err := os.Open(fs.Path("net/ip_vs_stats"))
if err != nil {
return IPVSStats{}, err
}
defer file.Close()
return parseIPVSStats(file)
}
// parseIPVSStats performs the actual parsing of `ip_vs_stats`.
func parseIPVSStats(file io.Reader) (IPVSStats, error) {
var (
statContent []byte
statLines []string
statFields []string
stats IPVSStats
)
statContent, err := ioutil.ReadAll(file)
if err != nil {
return IPVSStats{}, err
}
statLines = strings.SplitN(string(statContent), "\n", 4)
if len(statLines) != 4 {
return IPVSStats{}, errors.New("ip_vs_stats corrupt: too short")
}
statFields = strings.Fields(statLines[2])
if len(statFields) != 5 {
return IPVSStats{}, errors.New("ip_vs_stats corrupt: unexpected number of fields")
}
stats.Connections, err = strconv.ParseUint(statFields[0], 16, 64)
if err != nil {
return IPVSStats{}, err
}
stats.IncomingPackets, err = strconv.ParseUint(statFields[1], 16, 64)
if err != nil {
return IPVSStats{}, err
}
stats.OutgoingPackets, err = strconv.ParseUint(statFields[2], 16, 64)
if err != nil {
return IPVSStats{}, err
}
stats.IncomingBytes, err = strconv.ParseUint(statFields[3], 16, 64)
if err != nil {
return IPVSStats{}, err
}
stats.OutgoingBytes, err = strconv.ParseUint(statFields[4], 16, 64)
if err != nil {
return IPVSStats{}, err
}
return stats, nil
}
// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs.
func NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
fs, err := NewFS(DefaultMountPoint)
if err != nil {
return []IPVSBackendStatus{}, err
}
return fs.NewIPVSBackendStatus()
}
// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
func (fs FS) NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
file, err := os.Open(fs.Path("net/ip_vs"))
if err != nil {
return nil, err
}
defer file.Close()
return parseIPVSBackendStatus(file)
}
func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
var (
status []IPVSBackendStatus
scanner = bufio.NewScanner(file)
proto string
localMark string
localAddress net.IP
localPort uint16
err error
)
for scanner.Scan() {
fields := strings.Fields(scanner.Text())
if len(fields) == 0 {
continue
}
switch {
case fields[0] == "IP" || fields[0] == "Prot" || fields[1] == "RemoteAddress:Port":
continue
case fields[0] == "TCP" || fields[0] == "UDP":
if len(fields) < 2 {
continue
}
proto = fields[0]
localMark = ""
localAddress, localPort, err = parseIPPort(fields[1])
if err != nil {
return nil, err
}
case fields[0] == "FWM":
if len(fields) < 2 {
continue
}
proto = fields[0]
localMark = fields[1]
localAddress = nil
localPort = 0
case fields[0] == "->":
if len(fields) < 6 {
continue
}
remoteAddress, remotePort, err := parseIPPort(fields[1])
if err != nil {
return nil, err
}
weight, err := strconv.ParseUint(fields[3], 10, 64)
if err != nil {
return nil, err
}
activeConn, err := strconv.ParseUint(fields[4], 10, 64)
if err != nil {
return nil, err
}
inactConn, err := strconv.ParseUint(fields[5], 10, 64)
if err != nil {
return nil, err
}
status = append(status, IPVSBackendStatus{
LocalAddress: localAddress,
LocalPort: localPort,
LocalMark: localMark,
RemoteAddress: remoteAddress,
RemotePort: remotePort,
Proto: proto,
Weight: weight,
ActiveConn: activeConn,
InactConn: inactConn,
})
}
}
return status, nil
}
func parseIPPort(s string) (net.IP, uint16, error) {
var (
ip net.IP
err error
)
switch len(s) {
case 13:
ip, err = hex.DecodeString(s[0:8])
if err != nil {
return nil, 0, err
}
case 46:
ip = net.ParseIP(s[1:40])
if ip == nil {
return nil, 0, fmt.Errorf("invalid IPv6 address: %s", s[1:40])
}
default:
return nil, 0, fmt.Errorf("unexpected IP:Port: %s", s)
}
portString := s[len(s)-4:]
if len(portString) != 4 {
return nil, 0, fmt.Errorf("unexpected port string format: %s", portString)
}
port, err := strconv.ParseUint(portString, 16, 16)
if err != nil {
return nil, 0, err
}
return ip, uint16(port), nil
}