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|
package bonafide
import (
"errors"
"log"
"math/rand"
"sort"
"strconv"
"time"
)
const (
maxGateways = 3
)
// Load reflects the fullness metric that menshen returns, if available.
type Load struct {
gateway *Gateway
Fullness float64
Overload bool
}
// A Gateway is a representation of gateways that is independent of the api version.
// If a given physical location offers different transports, they will appear
// as separate gateways, so make sure to filter them.
type Gateway struct {
Host string
IPAddress string
Location string
LocationName string
CountryCode string
Ports []string
Protocols []string
Options map[string]string
Transport string
}
/* gatewayDistance is used in the timezone distance fallback */
type gatewayDistance struct {
gateway Gateway
distance int
}
type gatewayPool struct {
/* available is the unordered list of gateways from eip-service, we use if as source-of-truth for now. */
available []Gateway
userChoice string
/* byLocation is a map from location to an array of hostnames */
byLocation map[string][]*Gateway
/* recommended is an array of hostnames, fetched from the old geoip service. */
recommended []Load
/* TODO locations are just used to get the timezone for each gateway. I
* think it's easier to just merge that info into the version-agnostic
* Gateway, that is passed from the eipService, and do not worry with
* the location here */
locations map[string]Location
}
func (gw Gateway) isTransport(transport string) bool {
return transport == "any" || gw.Transport == transport
}
func (p *gatewayPool) populateLocationList() {
for i, gw := range p.available {
p.byLocation[gw.Location] = append(p.byLocation[gw.Location], &p.available[i])
}
}
func (p *gatewayPool) getLocations() []string {
c := make([]string, 0)
if p == nil || p.byLocation == nil || len(p.byLocation) == 0 {
return c
}
if len(p.byLocation) != 0 {
for city := range p.byLocation {
c = append(c, city)
}
}
return c
}
func (p *gatewayPool) isValidLocation(location string) bool {
locations := p.getLocations()
valid := stringInSlice(location, locations)
return valid
}
/* returns a map of location: fullness for the ui to use */
func (p *gatewayPool) listLocationFullness(transport string) map[string]float64 {
locations := p.getLocations()
cm := make(map[string]float64)
if len(p.recommended) != 0 {
for _, gw := range p.recommended {
if _, ok := cm[gw.gateway.Location]; ok {
continue
}
cm[gw.gateway.Location] = gw.Fullness
}
} else {
for _, location := range locations {
cm[location] = -1
}
}
return cm
}
/* this method should only be used if we have no usable menshen list. */
func (p *gatewayPool) getRandomGatewaysByLocation(location, transport string) ([]Gateway, error) {
if !p.isValidLocation(location) {
return []Gateway{}, errors.New("bonafide: BUG not a valid location: " + location)
}
gws := p.byLocation[location]
if len(gws) == 0 {
return []Gateway{}, errors.New("bonafide: BUG no gw for location: " + location)
}
r := rand.New(rand.NewSource(time.Now().Unix()))
r.Shuffle(len(gws), func(i, j int) { gws[i], gws[j] = gws[j], gws[i] })
var gateways []Gateway
for _, gw := range gws {
if gw.isTransport(transport) {
gateways = append(gateways, *gw)
}
if len(gateways) == maxGateways {
break
}
}
if len(gateways) == 0 {
return []Gateway{}, errors.New("bonafide: BUG could not find any gateway for that location")
}
return gateways, nil
}
func (p *gatewayPool) getGatewaysFromMenshenByLocation(location, transport string) ([]Gateway, error) {
if !p.isValidLocation(location) {
return []Gateway{}, errors.New("bonafide: BUG not a valid location: " + location)
}
gws := p.byLocation[location]
if len(gws) == 0 {
return []Gateway{}, errors.New("bonafide: BUG no gw for location: " + location)
}
var gateways []Gateway
for _, gw := range p.recommended {
if !gw.gateway.isTransport(transport) {
continue
}
for _, locatedGw := range gws {
if locatedGw.Host == gw.gateway.Host {
gateways = append(gateways, *locatedGw)
break
}
}
if len(gateways) == maxGateways {
break
}
}
if len(gateways) == 0 {
return []Gateway{}, errors.New("bonafide: BUG could not find any gateway for that location")
}
return gateways, nil
}
/* used when we select a hostname in the ui and we want to know the gateway details */
func (p *gatewayPool) getGatewayByHost(host string) (Gateway, error) {
for _, gw := range p.available {
if gw.Host == host {
return gw, nil
}
}
return Gateway{}, errors.New("bonafide: not a valid host name")
}
/* used when we want to know gateway details after we know what IP openvpn has connected to */
func (p *gatewayPool) getGatewayByIP(ip string) (Gateway, error) {
for _, gw := range p.available {
if gw.IPAddress == ip {
return gw, nil
}
}
return Gateway{}, errors.New("bonafide: not a valid ip address")
}
/* this perhaps could be made more explicit */
func (p *gatewayPool) setAutomaticChoice() {
p.userChoice = ""
}
/* set a user manual override for gateway location */
func (p *gatewayPool) setUserChoice(location string) error {
if !p.isValidLocation(location) {
return errors.New("bonafide: not a valid city for gateway choice")
}
p.userChoice = location
return nil
}
func (p *gatewayPool) isManualLocation() bool {
return len(p.userChoice) != 0
}
/* set the recommended field from an ordered array. needs to be modified if menshen passed an array of Loads */
func (p *gatewayPool) setRecommendedGateways(geo *geoLocation) {
var recommended []Load
if len(geo.SortedGateways) != 0 {
for _, gw := range geo.SortedGateways {
found := false
for i := range p.available {
if p.available[i].Host == gw.Host {
recommendedGw := Load{
Fullness: gw.Fullness,
Overload: gw.Overload,
gateway: &p.available[i],
}
recommended = append(recommended, recommendedGw)
found = true
}
}
if !found {
log.Println("ERROR: invalid host in recommended list of hostnames", gw.Host)
return
}
}
} else {
// If there is not sorted gatways, it means that the old menshen API is being used
// let's use the list of hosts then
for _, host := range geo.Gateways {
found := false
for i := range p.available {
if p.available[i].Host == host {
recommendedGw := Load{
Fullness: -1,
gateway: &p.available[i],
}
recommended = append(recommended, recommendedGw)
found = true
}
}
if !found {
log.Println("ERROR: invalid host in recommended list of hostnames", host)
return
}
}
}
p.recommended = recommended
}
/* get at most max gateways. the method of picking depends on whether we're
* doing manual override, and if we got useful info from menshen */
func (p *gatewayPool) getBest(transport string, tz, max int) ([]Gateway, error) {
if p.isManualLocation() {
if len(p.recommended) != 0 {
return p.getGatewaysFromMenshenByLocation(p.userChoice, transport)
} else {
return p.getRandomGatewaysByLocation(p.userChoice, transport)
}
} else if len(p.recommended) != 0 {
return p.getGatewaysFromMenshen(transport, max)
} else {
return p.getGatewaysByTimezone(transport, tz, max)
}
}
func (p *gatewayPool) getAll(transport string, tz int) ([]Gateway, error) {
if len(p.recommended) != 0 {
return p.getGatewaysFromMenshen(transport, 999)
}
return p.getGatewaysByTimezone(transport, tz, 999)
}
/* picks at most max gateways, filtering by transport, from the ordered list menshen returned */
func (p *gatewayPool) getGatewaysFromMenshen(transport string, max int) ([]Gateway, error) {
gws := make([]Gateway, 0)
for _, gw := range p.recommended {
if !gw.gateway.isTransport(transport) {
continue
}
gws = append(gws, *gw.gateway)
if len(gws) == max {
break
}
}
return gws, nil
}
/* the old timezone based heuristic, when everything goes wrong */
func (p *gatewayPool) getGatewaysByTimezone(transport string, tzOffsetHours, max int) ([]Gateway, error) {
gws := make([]Gateway, 0)
gwVector := []gatewayDistance{}
for _, gw := range p.available {
if !gw.isTransport(transport) {
continue
}
distance := 13
gwOffset, err := strconv.Atoi(p.locations[gw.Location].Timezone)
if err != nil {
log.Printf("Error sorting gateways: %v", err)
return gws, err
}
distance = tzDistance(tzOffsetHours, gwOffset)
gwVector = append(gwVector, gatewayDistance{gw, distance})
}
rand.Seed(time.Now().UnixNano())
cmp := func(i, j int) bool {
if gwVector[i].distance == gwVector[j].distance {
return rand.Intn(2) == 1
}
return gwVector[i].distance < gwVector[j].distance
}
sort.Slice(gwVector, cmp)
for _, gw := range gwVector {
gws = append(gws, gw.gateway)
if len(gws) == max {
break
}
}
return gws, nil
}
func newGatewayPool(eip *eipService) *gatewayPool {
p := gatewayPool{}
p.available = eip.getGateways()
p.locations = eip.Locations
p.byLocation = make(map[string][]*Gateway)
p.populateLocationList()
return &p
}
func tzDistance(offset1, offset2 int) int {
abs := func(x int) int {
if x < 0 {
return -x
}
return x
}
distance := abs(offset1 - offset2)
if distance > 12 {
distance = 24 - distance
}
return distance
}
func stringInSlice(a string, list []string) bool {
for _, b := range list {
if b == a {
return true
}
}
return false
}
|