summaryrefslogtreecommitdiff
path: root/pkg/specgen/generate/ports.go
blob: 6cf83ed819d6c62861ce89a6ea949c030ae9f563 (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
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
package generate

import (
	"context"
	"net"
	"strconv"
	"strings"

	"github.com/containers/podman/v3/libpod/image"
	"github.com/containers/podman/v3/pkg/specgen"
	"github.com/cri-o/ocicni/pkg/ocicni"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
)

const (
	protoTCP  = "tcp"
	protoUDP  = "udp"
	protoSCTP = "sctp"
)

// Parse port maps to OCICNI port mappings.
// Returns a set of OCICNI port mappings, and maps of utilized container and
// host ports.
func parsePortMapping(portMappings []specgen.PortMapping) ([]ocicni.PortMapping, map[string]map[string]map[uint16]uint16, map[string]map[string]map[uint16]uint16, error) {
	// First, we need to validate the ports passed in the specgen, and then
	// convert them into CNI port mappings.
	type tempMapping struct {
		mapping      ocicni.PortMapping
		startOfRange bool
		isInRange    bool
	}
	tempMappings := []tempMapping{}

	// To validate, we need two maps: one for host ports, one for container
	// ports.
	// Each is a map of protocol to map of IP address to map of port to
	// port (for hostPortValidate, it's host port to container port;
	// for containerPortValidate, container port to host port.
	// These will ensure no collisions.
	hostPortValidate := make(map[string]map[string]map[uint16]uint16)
	containerPortValidate := make(map[string]map[string]map[uint16]uint16)

	// Initialize the first level of maps (we can't really guess keys for
	// the rest).
	for _, proto := range []string{protoTCP, protoUDP, protoSCTP} {
		hostPortValidate[proto] = make(map[string]map[uint16]uint16)
		containerPortValidate[proto] = make(map[string]map[uint16]uint16)
	}

	postAssignHostPort := false

	// Iterate through all port mappings, generating OCICNI PortMapping
	// structs and validating there is no overlap.
	for _, port := range portMappings {
		// First, check proto
		protocols, err := checkProtocol(port.Protocol, true)
		if err != nil {
			return nil, nil, nil, err
		}

		// Validate host IP
		hostIP := port.HostIP
		if hostIP == "" {
			hostIP = "0.0.0.0"
		}
		if ip := net.ParseIP(hostIP); ip == nil {
			return nil, nil, nil, errors.Errorf("invalid IP address %s in port mapping", port.HostIP)
		}

		// Validate port numbers and range.
		len := port.Range
		if len == 0 {
			len = 1
		}
		containerPort := port.ContainerPort
		if containerPort == 0 {
			return nil, nil, nil, errors.Errorf("container port number must be non-0")
		}
		hostPort := port.HostPort
		if uint32(len-1)+uint32(containerPort) > 65535 {
			return nil, nil, nil, errors.Errorf("container port range exceeds maximum allowable port number")
		}
		if uint32(len-1)+uint32(hostPort) > 65536 {
			return nil, nil, nil, errors.Errorf("host port range exceeds maximum allowable port number")
		}

		// Iterate through ports, populating maps to check for conflicts
		// and generating CNI port mappings.
		for _, p := range protocols {
			hostIPMap := hostPortValidate[p]
			ctrIPMap := containerPortValidate[p]

			hostPortMap, ok := hostIPMap[hostIP]
			if !ok {
				hostPortMap = make(map[uint16]uint16)
				hostIPMap[hostIP] = hostPortMap
			}
			ctrPortMap, ok := ctrIPMap[hostIP]
			if !ok {
				ctrPortMap = make(map[uint16]uint16)
				ctrIPMap[hostIP] = ctrPortMap
			}

			// Iterate through all port numbers in the requested
			// range.
			var index uint16
			for index = 0; index < len; index++ {
				cPort := containerPort + index
				hPort := hostPort
				// Only increment host port if it's not 0.
				if hostPort != 0 {
					hPort += index
				}

				if cPort == 0 {
					return nil, nil, nil, errors.Errorf("container port cannot be 0")
				}

				// Host port is allowed to be 0. If it is, we
				// select a random port on the host.
				// This will happen *after* all other ports are
				// placed, to ensure we don't accidentally
				// select a port that a later mapping wanted.
				if hPort == 0 {
					// If we already have a host port
					// assigned to their container port -
					// just use that.
					if ctrPortMap[cPort] != 0 {
						hPort = ctrPortMap[cPort]
					} else {
						postAssignHostPort = true
					}
				} else {
					testHPort := hostPortMap[hPort]
					if testHPort != 0 && testHPort != cPort {
						return nil, nil, nil, errors.Errorf("conflicting port mappings for host port %d (protocol %s)", hPort, p)
					}
					hostPortMap[hPort] = cPort

					// Mapping a container port to multiple
					// host ports is allowed.
					// We only store the latest of these in
					// the container port map - we don't
					// need to know all of them, just one.
					testCPort := ctrPortMap[cPort]
					ctrPortMap[cPort] = hPort

					// If we have an exact duplicate, just continue
					if testCPort == hPort && testHPort == cPort {
						continue
					}
				}

				// We appear to be clear. Make an OCICNI port
				// struct.
				// Don't use hostIP - we want to preserve the
				// empty string hostIP by default for compat.
				cniPort := ocicni.PortMapping{
					HostPort:      int32(hPort),
					ContainerPort: int32(cPort),
					Protocol:      p,
					HostIP:        port.HostIP,
				}
				tempMappings = append(
					tempMappings,
					tempMapping{
						mapping:      cniPort,
						startOfRange: port.Range > 1 && index == 0,
						isInRange:    port.Range > 1,
					},
				)
			}
		}
	}

	// Handle any 0 host ports now by setting random container ports.
	if postAssignHostPort {
		remadeMappings := make([]ocicni.PortMapping, 0, len(tempMappings))

		var (
			candidate int
			err       error
		)

		// Iterate over all
		for _, tmp := range tempMappings {
			p := tmp.mapping

			if p.HostPort != 0 {
				remadeMappings = append(remadeMappings, p)
				continue
			}

			hostIPMap := hostPortValidate[p.Protocol]
			ctrIPMap := containerPortValidate[p.Protocol]

			hostPortMap, ok := hostIPMap[p.HostIP]
			if !ok {
				hostPortMap = make(map[uint16]uint16)
				hostIPMap[p.HostIP] = hostPortMap
			}
			ctrPortMap, ok := ctrIPMap[p.HostIP]
			if !ok {
				ctrPortMap = make(map[uint16]uint16)
				ctrIPMap[p.HostIP] = ctrPortMap
			}

			// See if container port has been used elsewhere
			if ctrPortMap[uint16(p.ContainerPort)] != 0 {
				// Duplicate definition. Let's not bother
				// including it.
				continue
			}

			// Max retries to ensure we don't loop forever.
			for i := 0; i < 15; i++ {
				// Only get a random candidate for single entries or the start
				// of a range. Otherwise we just increment the candidate.
				if !tmp.isInRange || tmp.startOfRange {
					candidate, err = getRandomPort()
					if err != nil {
						return nil, nil, nil, errors.Wrapf(err, "error getting candidate host port for container port %d", p.ContainerPort)
					}
				} else {
					candidate++
				}

				if hostPortMap[uint16(candidate)] == 0 {
					logrus.Debugf("Successfully assigned container port %d to host port %d (IP %s Protocol %s)", p.ContainerPort, candidate, p.HostIP, p.Protocol)
					hostPortMap[uint16(candidate)] = uint16(p.ContainerPort)
					ctrPortMap[uint16(p.ContainerPort)] = uint16(candidate)
					p.HostPort = int32(candidate)
					break
				}
			}
			if p.HostPort == 0 {
				return nil, nil, nil, errors.Errorf("could not find open host port to map container port %d to", p.ContainerPort)
			}
			remadeMappings = append(remadeMappings, p)
		}
		return remadeMappings, containerPortValidate, hostPortValidate, nil
	}

	finalMappings := []ocicni.PortMapping{}
	for _, m := range tempMappings {
		finalMappings = append(finalMappings, m.mapping)
	}

	return finalMappings, containerPortValidate, hostPortValidate, nil
}

// Make final port mappings for the container
func createPortMappings(ctx context.Context, s *specgen.SpecGenerator, img *image.Image) ([]ocicni.PortMapping, error) {
	finalMappings, containerPortValidate, hostPortValidate, err := parsePortMapping(s.PortMappings)
	if err != nil {
		return nil, err
	}

	// If not publishing exposed ports, or if we are publishing and there is
	// nothing to publish - then just return the port mappings we've made so
	// far.
	if !s.PublishExposedPorts || (len(s.Expose) == 0 && img == nil) {
		return finalMappings, nil
	}

	logrus.Debugf("Adding exposed ports")

	// We need to merge s.Expose into image exposed ports
	expose := make(map[uint16]string)
	for k, v := range s.Expose {
		expose[k] = v
	}
	if img != nil {
		inspect, err := img.InspectNoSize(ctx)
		if err != nil {
			return nil, errors.Wrapf(err, "error inspecting image to get exposed ports")
		}
		for imgExpose := range inspect.Config.ExposedPorts {
			// Expose format is portNumber[/protocol]
			splitExpose := strings.SplitN(imgExpose, "/", 2)
			num, err := strconv.Atoi(splitExpose[0])
			if err != nil {
				return nil, errors.Wrapf(err, "unable to convert image EXPOSE statement %q to port number", imgExpose)
			}
			if num > 65535 || num < 1 {
				return nil, errors.Errorf("%d from image EXPOSE statement %q is not a valid port number", num, imgExpose)
			}
			// No need to validate protocol, we'll do it below.
			if len(splitExpose) == 1 {
				expose[uint16(num)] = "tcp"
			} else {
				expose[uint16(num)] = splitExpose[1]
			}
		}
	}

	// There's been a request to expose some ports. Let's do that.
	// Start by figuring out what needs to be exposed.
	// This is a map of container port number to protocols to expose.
	toExpose := make(map[uint16][]string)
	for port, proto := range expose {
		// Validate protocol first
		protocols, err := checkProtocol(proto, false)
		if err != nil {
			return nil, errors.Wrapf(err, "error validating protocols for exposed port %d", port)
		}

		if port == 0 {
			return nil, errors.Errorf("cannot expose 0 as it is not a valid port number")
		}

		// Check to see if the port is already present in existing
		// mappings.
		for _, p := range protocols {
			ctrPortMap, ok := containerPortValidate[p]["0.0.0.0"]
			if !ok {
				ctrPortMap = make(map[uint16]uint16)
				containerPortValidate[p]["0.0.0.0"] = ctrPortMap
			}

			if portNum := ctrPortMap[port]; portNum == 0 {
				// We want to expose this port for this protocol
				exposeProto, ok := toExpose[port]
				if !ok {
					exposeProto = []string{}
				}
				exposeProto = append(exposeProto, p)
				toExpose[port] = exposeProto
			}
		}
	}

	// We now have a final list of ports that we want exposed.
	// Let's find empty, unallocated host ports for them.
	for port, protocols := range toExpose {
		for _, p := range protocols {
			// Find an open port on the host.
			// I see a faint possibility that this will infinite
			// loop trying to find a valid open port, so I've
			// included a max-tries counter.
			hostPort := 0
			tries := 15
			for hostPort == 0 && tries > 0 {
				// We can't select a specific protocol, which is
				// unfortunate for the UDP case.
				candidate, err := getRandomPort()
				if err != nil {
					return nil, err
				}

				// Check if the host port is already bound
				hostPortMap, ok := hostPortValidate[p]["0.0.0.0"]
				if !ok {
					hostPortMap = make(map[uint16]uint16)
					hostPortValidate[p]["0.0.0.0"] = hostPortMap
				}

				if checkPort := hostPortMap[uint16(candidate)]; checkPort != 0 {
					// Host port is already allocated, try again
					tries--
					continue
				}

				hostPortMap[uint16(candidate)] = port
				hostPort = candidate
				logrus.Debugf("Mapping exposed port %d/%s to host port %d", port, p, hostPort)

				// Make a CNI port mapping
				cniPort := ocicni.PortMapping{
					HostPort:      int32(candidate),
					ContainerPort: int32(port),
					Protocol:      p,
					HostIP:        "",
				}
				finalMappings = append(finalMappings, cniPort)
			}
			if tries == 0 && hostPort == 0 {
				// We failed to find an open port.
				return nil, errors.Errorf("failed to find an open port to expose container port %d on the host", port)
			}
		}
	}

	return finalMappings, nil
}

// Check a string to ensure it is a comma-separated set of valid protocols
func checkProtocol(protocol string, allowSCTP bool) ([]string, error) {
	protocols := make(map[string]struct{})
	splitProto := strings.Split(protocol, ",")
	// Don't error on duplicates - just deduplicate
	for _, p := range splitProto {
		p = strings.ToLower(p)
		switch p {
		case protoTCP, "":
			protocols[protoTCP] = struct{}{}
		case protoUDP:
			protocols[protoUDP] = struct{}{}
		case protoSCTP:
			if !allowSCTP {
				return nil, errors.Errorf("protocol SCTP is not allowed for exposed ports")
			}
			protocols[protoSCTP] = struct{}{}
		default:
			return nil, errors.Errorf("unrecognized protocol %q in port mapping", p)
		}
	}

	finalProto := []string{}
	for p := range protocols {
		finalProto = append(finalProto, p)
	}

	// This shouldn't be possible, but check anyways
	if len(finalProto) == 0 {
		return nil, errors.Errorf("no valid protocols specified for port mapping")
	}

	return finalProto, nil
}

// Find a random, open port on the host
func getRandomPort() (int, error) {
	l, err := net.Listen("tcp", ":0")
	if err != nil {
		return 0, errors.Wrapf(err, "unable to get free TCP port")
	}
	defer l.Close()
	_, randomPort, err := net.SplitHostPort(l.Addr().String())
	if err != nil {
		return 0, errors.Wrapf(err, "unable to determine free port")
	}
	rp, err := strconv.Atoi(randomPort)
	if err != nil {
		return 0, errors.Wrapf(err, "unable to convert random port to int")
	}
	return rp, nil
}