summaryrefslogtreecommitdiff
path: root/pkg/vpn/bonafide/gateways.go
blob: 460d80f6a02b8e4c1c49fc7d7fe7b68be5b16e13 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
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 (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.Transport == 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.Transport != 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.Transport != 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.Transport != 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
}